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| VOLUME XIX.
LIBRARY | BIVIBIGN OF BOTANY @me : PLANT PATHSLSCY ‘ § Catulegue No...... Sakesess il 3% i -12-4959 SiSLIOTEEK Zr ihe ae ENT ICURBE : 1953.
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THE JOURNAL
OF
SOUTH AFRICAN BOTANY
PUBLISHED UNDER THE AUTHORITY OF THE TRUSTEES OF THE
NATIONAL BOTANIC GARDENS OF SOUTH AFRICA
KIRSTENBOSCH, NEWLANDS CAPE PROVINCE
EDITOR R. H. COMPTON, M.A. (Cantab.), F.R.S.S.Af., Hon. F.R.H.S.
ACTING DIRECTOR OF THE NATIONAL BOTANIC GARDENS, PROFESSOR EMERITUS IN THE UNIVERSITY OF CAPE TOWN.
THE JOURNAL OF SOUTH AFRICAN BOTANY.
VotumME XIX, 1953.
CONTENTS. PAGE Four New ALOEs FRoM Kenya Cotony. By Dr. G. W. Reynolds, Hon. D.Sc. (Cape Town), F.L.S. (With Plates I-VII) .. ee ue Bi : 1 Tue IpeENTITY OF ALOE SECUNDIFLORA ENGLER. By Dr. G. W. Reynolds. (With Plates VITI-X) .. : : 5 : 13 A New ALOE FROM SOMALILAND PRrotecTorRATE. By Dr. G. W. Reynolds (With Plate IX) : 5 he a 21 Tue IpeENnTITY OF ALOE JOHNSTONH Bak.: A New Synonym. By Dr. G. W. Reynolds. (With Plates XII-XIIT) .. an ; 25 A Note on Sex in RoyeNna GuaBra L. (EBENACEAE). By Capt. T. M. Salter, R.N. (Retd.) Be ae a ss 29 KaRYOLOGICAL STUDIES AND CHROMOSOME NUMBERS IN HYPARRHENIA AUCTA anp H. nirta. By Dr. Stefan Krupko, Ph.D. (Warsaw). (With Plates XIV-XV) of #: EF: ay oe ey. te a 31 South AFRicaN SEAWEED VEGETATION AND FuTURE INVESTIGATIONS IN THIs FieLp. By Professor W. Edwyn Isaac, B.Sc.. Ph.D., F.R.S.S.Af. -. 59 Tar MorpHoLocy, GEoGRAPHICAL DIsTRIBUTION AND EcoLtocy oF HyPNEA SPICIFERA (SUHR) Harv. By Professor W. Edwyn Isaac and Miss Florence Hewitt. (With Plates XVI-XVII) a st: as 73 SEAWEED Resources oF SoutH Arrica. By Professor W. Edwyn Isaac and C.J. Molteno .. be a of. isis ae ve ov: te 85 On THE History oF PLanT STUDY UPON THE WITWATERSRAND. By Dr. H. B. Gilliland, D.Se. .. be ae 93 Puantar Novak ArricaNak. SeRtES XXXI. By Professor R. H. Compton, M.A., F.R.S.S.Af. (With Plate XVIII) a a oe ~ ae LOS A New Svuccunent EvuPHORBIA FROM THE WESTERN CAPE Province. By ; Dr. R. A. Dyer, M.Sc., D.Sc., F.R.S.S.Af. (With Plate XIX) .. .. 135 TuREE SmatL Spectus or OrHonna. By Professor R. H. Compton. (With re
Plate XX)
A New Crassuna FROM THE RicuTERSvELD. By H. Herre. (With Plate XXI) 146
SIIcULARIA. A NEW GENUS OF CRUCIFERAE. WITH NOTES ON RELATED GENERA. By Professor R. H. Compton
NoTEs oN NOMENCLATURE IN Licutrootis. By Professor R. 8. Adamson. M.A.. D.Sc., F.B.S.S.Af.
ALTEN PLANTS GROWING WITHOUT CULTIVATION IN THE SOMERSET WEST NEIGHBOURHOOD. By R. N. Parker
ADDENDA ET CORRIGENDA TO THE Woopy PLANTS OF THE BECHUANALAND Protectorate. By O. B. Miller. L.S.0.. F.LS.
REVIEWS:
L. E. W. Codd. Trees and Shrubs of the Krger National Park. lees R. H. Com pton.)
H. N. and A. L. Moldenke, Plants of ‘he Bible. (Pusan Lig tile ¢ om io C. yan Dillwijn, Botany of Sugar Cane. (Professor R. H. Compton) J.J. Finan, Maize in the Great Herbals. (Professor R. H. Compton)
R. Story, A Botanical Survey of the Keiskammahoek District. ee I? 8. Adamson) 42
E. M. van Zinderen Bakker, South African Pollen Gee and Spores, Part J. (Mr. 8. Garside) .
R. Good, The Geoeree Ly of the Flowering Plants: aa I. (Professor Ro:
Compton)
W. Crocker and L. V. Barton. Physiology of seas (Profesor W. Baym Isaac) 2A
L. M. Cranwell. New Zealand Pollen Studies. The Monomegieiode ot r. S. Garside) .. ; ahs
IspEx oF Prant Names, Vou. XIX
PAGE
147
ISSUED
FEB 18 19653
JOURNAL OF SOUTH AFRICAN BOTANY VOL. XIX.
FOUR NEW ALOES FROM KENYA COLONY By G. W. REYNOLDS. (With Plates I—VII.)
With the passing of Mr. H. Basil Christian, who contributed so much to the advancement of knowledge of the Aloes of Tropical Africa, and with the Aloes of South Africa having been monographed, it is now my hopeful ambition to investigate and eventually to monograph, the Aloes of Tropical Africa.
The descriptions of most of the earliest described species of Aloe from East Africa are incomplete, vague, and sometimes misleading, while there are no figures of most of them. Some type material in Berlin was, unfortunately, destroyed during the war, while such type material as does exist today, is mostly incomplete, fragmentary, and more exasperating than helpful. In some cases, leaves and habit of growth were unknown.
It soon became clear, that nothing less than a personal visit to the actual type localities, would ever enable me to solve the problem of the identity of most of these early Aloes—or at least to attempt it.
Consequently, at the invitation of Mr. P. R. O. Bally, Botanist at the Coryndon Museum, Nairobi, I flew to Nairobi in March 1952, and together we travelled 4,300 miles in six weeks, visiting all the Aloe type localities in Northern Tanganyika, i.e. Kilimanjaro, the Northern and Southern Pare Mountains, the Western and Kastern Usambara Moun- tains, and several in Kenya and Uganda.
In Kenya we travelled from Mombasa to Witu beyond the Tana River, returned to Nairobi, then went through the Rift Valley to Nakuru, Thomson’s Falls, Nanyuki and beyond Isiolo, thence westwards via Tororo and Jinja to Entebbe in Uganda, where A. dawei Berger, the last of the early species needed to complete the investigations, was found.
1
bo
The Journal of South African Botany.
These journeys were highly successful, and all but two of the earliest described Aloes in the area covered. can now be identified with reasonable certainty, while several new species of Aloe were found. Many photo- graphs were taken, much herbarium material gathered, and copious field notes written up, almost all of which have been sent to the National Herbarium, Pretoria, and the Royal Botanic Gardens, Kew.
I am grateful to Mr. Bally for his invaluable help, to Dr. L. 8S. Leakey, Curator of the Coryndon Museum, Nairobi, and to Mr. P. Greenway, O.B.E., for much assistance.
Papers establishing the identity of some of the earliest described Aloes are being prepared for publication, while several new species await description, of which four are described hereunder.
B. J.
Aloe ballyi Reynolds. Spec. nov. Nulli alii arcte affinis; forsitan sectionem propriam constituere debet.
Planta succulenta; truncus simplex, glaber, gracilis, aetate 6—8 met. altus, 1O—15 cm. crass. Folia ca. 25, dense rosulata, usque ad 90cm. longa, basi 14cm. lata, longe-attenuata, profunde canaliculata, griseo- viridula, glabra, immaculata, dentibus marginibus albidis 4—5mm. longis, 10—l5mm. distantibus armata. Inflorescentia multi-ramosa, ca. 60cm. longa et lata. Racemi ca. 14cm. longi, subsecundi, sublaxe ca. 20-floribus. Bracteae ovato-acutae, 5mm. longae, 5mm. latae, scariosae, sordide-albidae. ca. 5-nervatae. Pedicelli 10mm. longi. Perigonium carminatum, cylindricum, 33mm. longum, basi 9mm. diam.; segmenta exteriora per 22mm. libera. Antherae 4—5mm. exsertae. Stigma demum 5mm. exsertae. Ovarium 6mm. longum, 4mm. diam. [Plates I, I1.]}
Hab. Kenya Colony: Indense bush 23 miles west of Mwatate, 20 miles West of Voi (approx. 3°30’S 38°23’E), alt. 3,000 ft., fl. 31 March 1952, Reynolds 6378! (type) in Nat. Herb. Pretoria, with type number in Herb. Kew, and Cor. Mus. Herb. Nairobi.
Tanganyika Territory: S. Pare Mtns., Mamba Track, 17 June 1942, Greenway 6470! in E.A. Herb. Nairobi, and Nat. Herb. Pretoria; S. Pare Mtns., Kisiwani, 2 Feb. 1936, P. J. Greenway 4573! in Cor. Mus. Herb. Nairobi, “whole plant smells strongly of mice’.
Our new species is named after Mr. P. R. O. Bally, Botanist, Coryn- don Museum, Nairobi, who first found plants near Makania on the western side of the S. Pare Mtns. in September 1934, and again in December of that year near the top of the Manyara Escarpment beyond Lake Manyara and Mtuwambu on the road westwards from Arusha via Makuyuni to Ngorongoro Crater, in Tanganyika Territory. He has also
Four New Aloes from Kenya Colony. 3
photographed plants on the Nguruman Escarpment near Oldonyo Sambu, north of Mount Meru, in Tanganyika Territory. The writer found it near Kisiwani, at the northern end of the S. Pare Mtns. in dense bush and in almost impenetrable thickets of Sansevieria and Euphorbia, growing socially with A. deserti Berger, Kisiwani being the type locality of the latter. Mr. P. J. Greenway records that A. ballyi is “locally common all down the eastern side of the S. Pare Mtns. on the foot slopes between 4,000—5,000 ft.”
A. ballyi is a very distinctive species with a tall, slender, simple stem reaching 20 feet and more in height. The leaves are deeply channelled and recurved, while old dried leaves fall, giving the stem a clean smooth appearance. The leaves and sap give off a permeating, very decided odour of rats or mice, on which account this species has for some time been known as the “Rat Aloe’’.
The inflorescence is produced sub-obliquely, with the reddish-orange flowers more or less secund, depending on the angle of the raceme; the more horizontal the raceme, the more secund the flowers.
On Mr. H. A. Delap’s Estate “Kayata”’, about 50 miles east of Nairobi, and east of Donyo Sabuk in dense bush near the Athi River, the writer noticed many tall simple-stemmed plants, and also several which branched from the base and formed large shrubs; but this is a form not typical of the species as a whole.
The flowering period appears to be from December to June, depending on the rains, and the locality. ;
Description: Stem slender, simple, 5—8 met. high, 10—l5em. thick, glabrous, the old leaves not persistent.
Leaves about 25, densely rosulate at apex of stem, lanceolate-long attenuate, up to 90cm. long, 14cm. broad at base, the youngest leaves spreading, the oldest much recurved, deeply canaliculate, and “U” shaped in cross-section; both surfaces grey-green, glabrous throughout, without spots or lineation; margins armed with laterally compressed deltoid, pungent, white teeth averaging 4—5mm. long, 10—l5mm. distant, more crowded nearer base of leaf, more distant upwards, the teeth sometimes forward-uncinnate, the interspaces straight.
Inflorescence a much branched panicle, about 60cm. long and broad, produced sub-obliquely.
Peduncle biconvex and 20mm. diam. at base, terete upwards, with about 20 branches from low down, the lowest re-branched, and sub- tended at base by a thin, dry, white bract about 18mm. broad, 14mm. long, about 7-nerved, the branches mostly spreading with the racemes
oblique.
+ The Journal of South African Botany.
Racemes up to 14cm. long, rather laxly about 20-flowered, the buds dull scarlet, tipped bluish-green, with a slight bloom, the open flowers carmine to reddish-orange, the pedicels upturned with the buds and flowers mostly subsecund to secund, depending on the degree of obliquity of the racemes. ;
Bracts clasping the pedicels, ovate-acute, 5mm. long, 5mm. broad at base, thin, scarious, dirty white, about 5-nerved.
Pedicels lowest 10mm. long, mostly up-curved.
Perianth carmine to reddish-orange, greyish-tipped, 33mm. long, cylindric, 9mm. diam. near base, exceedingly slightly constricted on under-side above the ovary, very slightly curved, the mouth wide open; outer segments free for two-thirds their length (tube 1lmm.), distinctly 3-nerved from base to apex, the nerves dull pale reddish, the apices subacute, slightly spreading: inner segments themselves free but dorsally adnate to the outer for one-third their length, broader than the outer, with their brownish-tipped apices more obtuse and more spreading than the outer, and with a prominent median nerve throughout.
Filaments pale lemon, filiform-flattened. the 3 inner narrower and lengthening in advance of the 3 outer. with their anthers in turn exserted 4—_ 5mm.
Style pale yellow, filiform, with the stigma at length exserted 5mm.
Ovary pale green. 6mm. long, 4mm. diam., finely 6-grooved.
Capsule for some time enwrapped with the dried remains of the perianth: mature fruits and seeds not seen.
Aloe kedongensis Reynolds. Spec. nov. in Sect. EvAaLor, subsect. Prolongatae.
Planta succulenta, fruticosa. Caules graciles usque ad 4 met. longi, 4cm. crass. Folia ex vaginis striatulis lineari-lanceolata, sensim attenuata, 30cm. longa et 3.5em. lata, patula vel recurvula, immaculata, canali- culata, dentibus marginibus 2—3mm. longis, 10mm. distantibus armata. Inflorescentia 50cm. alta, 2—4-ramosa. Racemi 10—12cm. longi, ca. 8cem. lati. Bracteae ovato-acutae, 5mm. longae et latae, 3-nervatae. Pedicelli 20—25mm. longi. Perigonium coccineum, 35mm. longum; segmenta exteriora per l4mm. libera. Antherae 2—3mm. exsertae. Stigma demum 4mm. exserta. Ovarium 7mm. longum, 3mm. diam. [Plates IIT, IV.]
Hab. Kenya Colony: Rift Valley, near Lake Naivasha, 2 miles south of Lake Hotel. 6 miles south of Naivasha, approx. 0°48’S 36°25’E, alt. 6,100 ft., fi. 19 April 1952, Reynolds 6546! (type) in Nat. Herb. Pretoria, with type number in Herb. Kew, and Cor. Mus. Herb. Nairobi: Gilgil
Four New Aloes from Kenya Colony. 5
Escarpment, 3 miles north-west of Gilgil, fl. 19 April 1952, Reynolds 6552! in Nat. Herb. Pretoria, Herb. Kew, and Cor. Mus. Herb. Nairobi; near top of Kedong Escarpment, 24 miles north-west of Nairobi, fl. 19 April 1952, Reynolds 6544! in Nat. Herb. Pretoria, and Herb. Kew.
A. kedongensis is named after that part of the Kenya portion of the Great Rift which appears to be the specific centre. It occurs in dense bush from near the top to near the foot of the Kedong Escarpment, 24—28 miles north-west of Nairobi, also on Mt. Longonot nearby, where Mr. P. R. O. Bally has collected it. At the type locality, which is 2 miles south of the Lake Hotel (6 miles south of Naivasha), near the south- eastern shore of Lake Naivasha, A. kedongensis occurs in flatter country in dense masses, sometimes forming untidy impenetrable thickets up to 12 feet high and several yards across. On dry slopes of volcanic rock near the southern extremity of Lake Naivasha, it is also found in large numbers growing socially with masses of A. secundiflora Engler. Although both species were seen in flower (April) no trace of hybrids was found.
A. kedongensis also grows in large numbers on rocky slopes of the Gilgil Escarpment, overlooking Lake Elmenteita, 2—3 miles north-west of Gilgil, and was also observed 10 miles south of Nakuru. During the last war Major A. G. McLoughlin sent plants from the Gilgil Escarpment, with photographs, to the Division of Botany, Pretoria.
Characters which distinguish A. kedongensis from its nearest allies, include slender spindly stems up to 4 met. long, and narrow leaves up to 30cm. long, but not exceeding 3}cm. broad at base, the leaves being unspotted and having small marginal teeth only 2—3mm. long.
Until such time as the Aloes of Africa have been investigated, and sections and groupings revised, A. kedongensis can be placed in the section HKuALOog, subsection Prolongatae.
A. rabaiensis Rendle, which I have seen from near Mombasa to near Nairobi, differs in having thicker stems, much larger greyer leaves, and smaller almost capitate racemes, and could never be confused.
A. nyeriensis Christian, which occurs near Nanyuki and southwards along the Nyeri road, has much larger leaves, and much thicker stems which are slenderer near base becoming thicker upwards.
A. pole-evansii Christian from near Kisumu has thicker stems, larger leaves, and different racemes.
A. dawei Berger, which I have seen near Entebe in Uganda, is a totally different species with thicker stems about | met. or a little more long, and much larger different leaves.
Description. Plants succulent, fruticose, forming shrubs varying from
6 The Journal of South African Botany.
2 met. high to dense thickets 3—4 met. high and sometimes several metres across.
Stems slender, spindly, about 4cem. thick, up to 4 met. tall, mostly branched from the base, sometimes with few to many shoots produced at random, the terminal 30—60cm. of main stems sublaxly foliate, with the internodes 2—3cm. distant, the sheaths obscurely striate; the apical portion of stems usually with old dried leaves persistent for about 1 met., nude downwards.
Leaves dull greyish-green to dull yellowish-green, basally sheathing, 3.5em. broad at base, 30cm. long, gradually narrowing from base to apex, varying from spreading to recurved: upper surface canaliculate, lower surface rounded: both surfaces unspotted except sometimes in young shoots, the spots disappearing with age; margins armed with pale deltoid teeth with reddish-brown apices, the teeth sometimes forward-uncinnate and averaging 2—3mm. long, 10mm. distant.
Inflorescence 50cm. tall, 2—4-branched from about the middle, the branches mostly arcuate-ascending.
Peduncle brown with a slight bloom, basally plano-convex and 12—15mm. diam., terete upwards, the lowest branch subtended at base by an ovate-cuspidate, thin, scarious, 5-nerved bract 6mm. long, 12mm. broad at base.
Racemes broadly cylindric-acuminate, the terminal 10—12cm. long, about 8cm. diam., laterals a little smaller.
Bracts ovate-acute, 5mm. long, 5mm. broad at base, thin, scarious, about 3-nerved.
Pedicels 20—25mm. long, the colour of the perianth.
Perianth scarlet. cylindric, slightly trigonous, averaging 35mm. long, shortly stipitate. obtusely tapering into the pedicel, 7mm. diam. over the ovary, thence slightly curved and very slightly constricted on the under- side only, the mouth wide open: outer segments free for 14mm. paler at their margins, 5-nerved, the apices subacute, spreading; inner segments themselves free but dorsally adnate to the outer for 20mm., broader than the outer and with more obtuse more spreading brownish apices.
Filaments pale-yellow, filiform-flattened, the 3 inner narrower and lengthening in advance of the 3 outer with their anthers in turn exserted
2—3mm. Style lemon, filiform, with stigma at length exserted 4mm.
Ovary green, 7mm. long, 3mm. diam., finely 6-grooved. Capsule 22mm. long, 9mm. diam., broadly 3-angled.
A. ngobitensis Reynolds. Spec. nov., in Sect. EvAaLor, subsect. Prolongatae. Planta succulenta, fruticosa, ca. 2 met. alta et lata.
Four New Aloes from Kenya Colony. a
Folia griseo-viridia, 35cm. longa, 5em. lata, sensim attenuata, patentia vel recurvula, dentibus marginibus-deltoideis 3—4mm. longis, 8—l12mm. distantibus armata. IJnflorescentia 80cm. alta, 3—5-ramosa. Racemi subdensi, 15cm. longi, Tem. diam. Bracteae ovato-acutae, scarlosae, 5mm. longae, 4mm. latae, 5-nervatae. Pedicelli 20mm. longi. Perigonium laete aureo-coccineum 36mm. longum, basi 7mm. diam; segmenta exteriora per 15mm. libera. Antherae per 3—4mm. exsertae. Stigma demum 5mm. exserta. [Plate V.]
Hab. Kenya Colony: Bushy slopes near Ngobit Bridge, 31 miles north-west of Nyeri on direct road to Mutara Police Post and Thomson’s Falls, approx. 0°5’S 36°50’E. Fl. 22 April 1952, Reynolds 6579! (type) in Nat. Herb. Pretoria, with type number in Herb. Kew and Cor. Mus. Herb. Nairobi; 18 miles east of Thomson’s Falls, fl. 22 April 1952, Rey- nolds 6559! in Nat. Herb. Pretoria, and Herb. Kew.
A. ngobitensis is named after the locality which appears to be its specific centre, namely, the valley of the Ngobit River, near Ngobit Bridge, 31 miles north-west of Nyeri, on the direct road from Nyeri to Mutara Police Post and Thomson’s Falls, Kenya Colony. For a mile or more each side of Ngobit Bridge, large numbers of plants were found on bushy slopes in stony ground, forming shrubs about 6 feet high and broad, and mostly branched from the base with the main stems slightly divergent.
The most striking feature of A. ngobitensis, and one which immediately distinguishes it from all other shrubby Aloes known to me in Kenya and elsewhere in Africa, is the remarkable colour of the flowers which are a striking and most attractive bright sheeny orange-scarlet, the peri- anth being usually minutely white-spotted. It is also distinguished by having rather slender peduncles and branches, and subdensely flowered somewhat narrow racemes about 15cm. long. Stems branch at ground level, very slightly increasing in thickness upwards, which is also a character of A. nyeriensis found further east near Nanyuki and for some miles along the road southwards towards Nyeri, but the latter is a larger plant with thicker stems, larger leaves, and different racemes with dull scarlet flowers, and could hardly be confused.
Near Ngobit Bridge, numbers of A. ngobitensis were seen growing socially with large numbers of A. secundiflora. Both were flowering in April, but no crosses were noticed.
At the Suguroi River 14 miles northwest of Ngobit Bridge (which locality is 32 miles west of Nanyuki and 28 miles east of Thomson’s Falls), A. ngobitensis was found among similar Aloe shrubs having slightly shorter denser racemes of dull scarlet flowers. Whether the latter are
8 The Journal of South African Botany.
colour forms of A. ngobitensis, or more probably forms of A. nyeriensis extending westwards from Nanyuki, requires further investigation.
At a point 18 miles east of Thomson’s Falls, an occasional plant of A. ngobitensis with its bright sheeny orange-scarlet flowers stood out vividly among numbers of Aloe shrubs with dull scarlet flowers. On account of its most attractive colour of flowers, A. ngobitensis is a plant well worth cultivating.
Description. Plants succulent, fruticose, forming shrubs about 2 met. high and broad.
Stems 2 met. tall, 4—5cem. diam., mostly branched from base, the terminal portion sublaxly foliate for 30—50cm., the old dried leaves persistent, with the lower half of stems nude.
Leaves 5cem. broad at base, gradually attenuate and 35cm. long, basally sheathing with the internodes 2—3cm. distant, the sheathing portion obscurely lineate: upper surface flat to slightly canaliculate; lower surface rounded; both surfaces grey-green, without lines or spots except sometimes in young shoots, the spots disappearing with age; margins armed with teeth the colour of the leaf at base, paler upwards and pale brown at apex, averaging 3—4mm. long, 8—l2mm. distant, the interspaces rounded.
Inflorescence 80cm. high, rather compactly 3—5-branched from about the middle.
Peduncle flattened at base, terete upwards, with the branches slender.
Racemes cylindric-acuminate, the terminal licm. long. 7cm. diam., subdensely flowered.
Bracts ovate-acute, 5mm. long, 4mm. broad at base, thin, scarious, about 5-nerved.
Pedicels the lowest of terminal racemes 20mm. long.
Perianth bright sheeny orange-scarlet, greenish tipped, 36mm. long, cylindric slightly trigonous, basally obtusely tapering into the pedicel, 7mm. diam. over the ovary, thence slightly constricted on the underside, enlarging slightly to the mouth; outer segments free for 15mm., paler at the edges, with the apices subacute, slightly spreading; inner segments themselves free but dorsally adnate to the outer for two-thirds their length, broader than the outer, and with more obtuse more spreading apices.
Filaments pale lemon, filiform-fiattened, the 3-inner narrower and lengthening in advance of the 3 outer, with their anthers in turn exserted 3—4mm.
Style pale yellow, filiform, with stigma at length exserted 5mm.
Ovary pale olive-green, 5mm. long, 3mm. diam., finely 6-grooved.
Four New Aloes from Kenya Colony. 9
Aloe graminicola Reynolds. Spec. nov. in ser. Saponariae, A. lateritia Engler affinis, sed floribus gracilioribus differt.
Planta succulenta, acaulis, dichotome divisa. Folia ca. 16, dense rosulata, lanceolata, patentia, usque ad 27cm. longa, basi 7em. lata; swpra obscure viridia, planiuscula, maculis oblongis lateraliter saepe confluentibus trans- verse seriatis picta; swhtus convexa, maculis transverse picta, ad margines sinuato-dentata, dentibus deltoideis 4—5mm. longis et 10—l5mm. inter se distantibus. Inflorescentia 1 met. alta, 3—5-ramosa. Racemi dense capitati, 5cm. longi, 8cm. diam. Bracteae anguste deltoideo-acuminatae, scariosae, 12mm. longae, 2mm. latae, 3—5-nervatae. Pedicelli 20mm. longi. Perigonium coccineum (interdum luteum), 33mm. longum; tubus circa ovarium globoso-inflatus et 8mm. diam., deinde constrictus et 5mm. diam., hine decurvatus et paullum ampliatus; segmenta exteriora per 8mm. libera. Antherae 1—2mm. exsertae. Stigma demum 2—3mm. exserta. Ovarium 6mm. longum, 24mm. diam. [Plates VI, VII.]
Hab. Kenya Colony: In open grassland 8 miles south of Nanyuki (116 miles north of Nairobi), approx. 0°5'S 37°4’E, alt. 6,200 ft., fl. 22 April 1952, Reynolds 6576! (type) in Nat. Herb. Pretoria, with type number in Herb. Kew, and Cor. Mus. Herb. Nairobi; } mile north of Nanyuki, alt. 6,300 ft., fl. 22 April 1952, Reynolds 6574! in Nat. Herb. and Herb. Kew; flat grasslands at Gilgil (74 miles north-west of Nairobi), 0°30’S 36°18’E, alt. 6,580 ft., fl. 19 April 1952, Reynolds 6551! in Nat. Herb. and Herb. Kew; flat grasslands near Ol Joro Orok, 33 miles north of Gilgil, 0°4’S 36°22’E, alt. 7,780 ft., fl. 20 April 1952, Reynolds 6554! in Nat. Herb. Pretoria, and Herb. Kew; Naro Moru (14 miles south of Nanyuki), Aug. 1932, E. R. Napier 2187! in E.A. Herb. and Cor. Mus. Herb. Nairobi.
Our new species is allied to A. lateritia Engler—which I have studied at the type locality, Rombo, on south-eastern foothills of Kilimanjaro— but differs from it, inter alia, in having smaller, denser, capitate racemes of much narrower more curved flowers. In A. graminicola the basal swelling of the perianth is also much smaller and the two species could hardly be confused.
Plants were found near Timau (14 miles north of Nanyuki), at Nan- yuki, and in large numbers 8 miles south of Nanyuki (type locality) in open grasslands, while yellow-flowered forms were noticed further south near Naro Moru. Considerable quantities occur for 30 miles north- westwards from Nyeri, near Thomson’s Falls, and from there to Ol Joro Orok. It was also seen in the Rift Valley near Nakuru, Gilgil and Nai- vasha, flowering in April.
10 The Journal of South African Botany.
In all localities visited, A. graminicola was found growing in grasslands, which suggested the specific epithet. I did not see this species on rocks, or in dry, arid thorn country. Altitudes from 6,000 ft. to 7,800 ft. in the Kenya Highlands, seem to suit it.
Between Njoro and Elburgon, some 20 miles west of Nakuru on the road to Mau Summit, it seems that A. graminicola grades through inter- mediates into A. /ateritia. Beyond the Mau Range, especially for 12 miles before reaching Eldoret, only robust forms of A. /ateritia were noticed. Beyond Eldoret, near Hoey’s Bridge, Kitale and to the north, there appear to be at least two more distinctive undescribed species in the Series Saponariae which require further investigation.
Description. Plant succulent, solitary, or forming small groups by division, acaulescent.
Leaves about 16, densely rosulate, erectly spreading, lanceolate- attenuate, up to 27cm. long. 7em. broad at base, the apex dried and twisted: upper surface flat or slightly canaliculate, dull green with numerous dull white “H’-shaped spots, the spots irregularly scattered or sometimes more or less arranged in interrupted undulating transverse bands; lower surface paler green, with fewer spots, the spots irregularly scattered or more or less arranged in interrupted undulating transverse bands: margins sinuate-dentate, with horny edge, armed with pale brown, pungent, deltoid teeth 4—5mm. long, 10—l5mm. distant, the interspaces rounded and the colour of the leaf. (Sap dries yellow.)
Inflorescence a branched panicle up to 1 met. high.
Peduncle brown with a grey powdery bloom, flattened and 2cm. diam. low down, terete upwards, 3—5-branched from the middle or higher, the lowest branch subtended at base by a rather fleshy many-nerved bract up to 3cm. long, 12mm. broad at base.
Racemes capitate, densely flowered, the terminal averaging 5cm.long, 8cm. diam., the lateral a little smaller.
Bracts narrowly deltoid-acuminate, thin, scarious, 12mm. long, 2mm. broad at base, 3—d-nerved.
Pedicels averaging 20mm. long.
Perianth scarlet to orange-scarlet (sometimes yellow), paler to yellowish at mouth, averaging 33mm. long, slender, with basal swelling 8mm. diam., constricted above the ovary to 5mm. diam., thence decurved, laterally compressed and enlarging towards the throat, outer segments free for 8mm., paler at the margins, the apices subacute, slightly spreading; inner segments broader than the outer, with broader thin white borders and more obtuse spreading apices.
Four New Aloes from Kenya Colony. 11
Filaments almost white, filiform-flattened, the 3 inner narrower and lengthening in advance of the 3 outer, with their anthers in turn exserted 1—2mm.
Style pale-yellow, filiform, with the stigma at length exserted 2—3mm.
Ovary pale green, 6mm. long, 24mm. diam., finely 6-grooved.
Capsule 32mm. long, 16mm. diam. at the middle.
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THE IDENTITY OF ALOE SECUN DIFLORA ENGLER
By G. W. REYNOLDs. (With Plates VITI— xX.)
The type of Aloe secundiflora is Volkens 530, in Herb. Berlin, a photograph of which has been sent to me by Prof. G. Werdermann, Dahlem. The type locality is (from the German): “Kilimanjaro District: At the foot of the Rhino Hills (Nashornhugels), in stony ground with Kuphorbia trees; leg. Volkens, 4 July 1893”.
The present place-name is Kifaru, which, in Swahili means Rhinoceros. Kifaru is situated at the northern extremity of the North Pare Mountains at approximately 3°35'S 37°33’E which is 9 miles south of Himo, Himo being 18 miles east of Moshi, Tanganyika Territory.
I visited the Rhino Hills in April 1952 (with Mr. P. R. O. Bally, botanist at the Coryndon Museum, Nairobi) for the purpose of investi- gating A. secundiflora at its type locality. Large numbers of plants were found at Kifaru in arid country, with tree Euphorbias, Acacia xantho- phloea, and Dum Palms (Hyphaene) nearby.
The identity of A. secundiflora can now be established with certainty, but two other species became involved, namely A. engleri Berger, and A. floramaculata Christian.
A. engleri was collected by Engler in 1902 and described by Berger in Engler Bot. Jahrb. 36: 60 (1905), the type locality being (from the German) “Kilimanjaro District: Between Taveta and the Bura Hills”.
Mr. Bally and I journeyed from Taveta (in Kenya Colony, near the Tanganyika border) eastwards to the Bura Hills, which are at the western end of the Teita Hills, to search for A. engleri. Large numbers of plants were found—many flowering—near Maktau, 34 miles east of Taveta, 38 miles west of Voi, and west of the Bura Hills, in Kenya Colony, at approximately 3°26’S 38°9’H.
Prof. G. Werdermann has also kindly sent me a photograph of the type material of A. engleri in Herb. Berlin. From this photograph, and from the description and locality, there can be no doubt whatever that the Maktau plants belong to A. engleri, but an examination revealed that they were, in all characters, identical with A. secundiflora at Kifaru. Consequently, A. engleri, being a later publication, cannot be upheld, and must go into synonymy.
Berger’s Fig. 94 in Engler Pflanzenr. Liliac.-Aloin. 252 (1908) of a whole plant of A. engleri shows the rosette of leaves approximately
13
14 The Journal of South African Botany.
correctly, but the inflorescence far from agrees with the type material, it does not fit the description, and is in all ways entirely misleading; in fact, it could only have been founded on imagination. Berger’s figure of a flower natural size is also wrong, and far from resembles the actual flower.
A difficulty with Berger’s figures is that, with most of the Tropical Aloes, he has obviously founded those of flowers natural size, on dried pressed Herbarium material. and has depicted shapes which he imagined the flowers had when alive, with the result that such figures are mostly inaccurate and misleading.
Aloe species which can readily be separated when alive often look much the same when pressed and dried. With Aloe, no sooner are racemes of flowers scalded, pressed and dried in the field, than some distinguishing characters are irretrievably lost. This applies especially to the small white specks or spots found in the perianth of both A. secundt- flora and “A. engleri’”, a character hitherto unrecorded in these two species.
The spotting of the perianth is one of the main characters noted by the late Mr. H. Basil Christian when describing his A. floramaculata from the Makumba Valley (south of Mwanza and Lake Victoria), Shin- yanga District, Tanganyika Territory. Mr. Christian submitted material to Dr. J. C. Hopkins, Chief Botanist and Plant Pathologist, Dept. of Agriculture, Salisbury, who reported: ““The pale specks on flowers are not due to a pigment. but are pale translucent spots or stripes caused by the presence of bubbles of gas in the sub-epidermal tissue. The gas does not appear to be enclosed in any special structure.”
Since the character “spotted perianth’’ was not mentioned in the description of A. secundiflora, Mr. Christian could hardly have been expected to know of it, while an examination of the actual type material could not have revealed it, since the minute gas-bubble spots disappear when flowers are pressed, and do not re-appear when dried flowers are boiled up.
I studied and photographed the type plant of A. floramaculata at Ewanrigg when flowering there in June 1939, and in the light of further knowledge, it now proves to be conspecific with A. secundiflora.
Subjoined is the synonymy, with a description based on personal observations of large numbers of plants over a wide area in parts of Tanganyika and Kenya.
A. secundiflora Engler in Pflanzenwelt Ostafrikas 140 (1895); Baker in Th. Dyer Fl. Trop. Afr. 7: 459 (1898); Berger in Engler Pflanzenr. Liliac.-Aloin. 267 (1908).
The Identity of Aloe secundiflora Engler. 15
—A. engleri Berger in Engler Bot. Jahrb. 36: 60 (1905), in Engler Pflanzenr. Liliac.-Aloin. 252 (1908). —A. floramaculata Christian in Journ. S.A. Bot. 6: 182 (1940).
Plants acaulescent or very shortly caulescent; mostly solitary, or in small groups, sometimes soboliferous.
Leaves about 20, densely rosulate, erectly spreading, slightly recurved near apex, ovate-lanceolate-attenuate, averaging 45cm. long, 12—14cm. broad at base, dull green, rather glossy, without spots: wpper surface flat low down, slightly canaliculate towards apex; lower surface rather flat low down, more rounded upwards; margins obtuse, sinuate-dentate, armed with laterally compressed deltoid teeth which are pungent, brown with paler tips, straight or hooked forward, averaging 4mm. long, 15mm. distant, the teeth isolated in younger leaves, sometimes joined by a horny brown marginal edge in older leaves. Sap dries yellow.
Inflorescence a divaricately branched panicle 1—1.75 met. high, sometimes 2 simultaneously, branched from below the middle with about 10—12 slender oblique branches, sometimes producing 50 and more racemes per inflorescence, the lowest branch subtended at base by a broadly ovate, thin, scarious, pale-brown, 7-nerved bract about 12mm. long, 20mm. broad at base.
Peduncle brown with a grey powdery bloom, plano-convex and 35mm. diam. at base, terete upwards, the branches slender, oblique.
Racemes more or less oblique, 15—20cm. long, rather laxly about 18-flowered, the flowers more or less secund, the buds rose-pink and greyish tipped, more clearly spotted, the open flowers usually less clearly spotted; the buds suberect and grouped along the top of branch, open flowers cernuous to pendulous, after pollination the drying perianth and fruit becoming erect.
Bracts ovate-acute or deltoid, thin, scarious, about 4—5mm. long, 4—5mm. broad at base, 3—5-nerved.
Pedicels 8—10mm. long.
Perianth rose-pink to dull scarlet-red, paler at mouth, obscurely to clearly minutely white-spotted, averaging 35mm. long, cylindric, basally flat and not at all stipitate, 9mm. diam. over the ovary, slightly constricted above the ovary, thence slightly trigonous and slightly enlarging to the open mouth; outer segments free for half their length, with paler margins and subacute spreading apices, obscurely 3-nerved, the nerves turning brownish at apex; inner segments themselves free but dorsally adnate to the outer and with broad pale border, with 3 congested nerves forming a keel throughout, the apices more obtuse and more spreading than the outer.
16 The Journal of South African Botany.
Filaments palest lemon, filiform-flattened, the 3 inner narrower and lengthening in advance of the 3 outer, with their anthers in turn exserted omm.
Style lemon, filiform, with stigma at length exserted 6mm.
Ovary pale green, 6mm. long, 3mm. diam., finely 6-grooved.
Note.—The soboliferous form occurs in the localities furthest west, i.e. the Shinyanga and Biharamulo Districts. In the Rift Valley (Lake Naivasha area) small groups are found, increasing by division and not from suckers. In localities furthest east, i.e. Kifaru, Maktau, Kinango, Mariakani, plants are mostly solitary and not in groups.
DISTRIBUTION.
A. secundiflora appears to be one of the most frequent and most widely distributed species of Aloe in the northern portion of Tanganyika Territory, and in parts of Kenya Colony. It is found from a few hundred feet above sea level to over 6,000 ft. in the Rift Valley and near Nanyuki, on the Equator.
From a few recorded localities, but mostly from personal observations, the following is the distribution as at present known:
Tanganyika Territory: From Biharamulo in the north-west, east- wards through the Shinyanga, Singida and Kondoa Districts to Arusha, Moshi, Lake Chala, and north of Kilimanjaro; from the northern end of the North Pare Mountains southwards to Kisangiro, and the Mwembe and Vudea valleys on the western side of the Southern Pare Mountains; also 18 miles north of Tanga.
Kenya Colony: Abundent near Kinango (36 miles west-south-west of Mombasa) and for the next 30 miles along the Tanga road; from Maria- kani (20 miles north-west of Mombasa) along the road to Voi, thence westwards to Maktau and Taveta; Sultan Hamud, occasional on the Kapiti Plains; Machakos; at the foot of Lukenya Hill; abundant at the Athi River road bridge, Stony Athi (20 miles south-east of Nairobi); east of Thika, near Donyo Sabuk; in the Kedong Valley (north-west of Nairobi); Mt. Margaret; near Mt. Longonot and at the southern end of Lake Naivasha; near Elmenteita; southwards along the Rift Valley to Olorgesailie Prehistoric Site; Kajiado; near Nanyuki (122 miles north of Nairobi); tremendous quantities 34 miles west of Nanyuki near the Mutara Police Post where, in April, the countryside is pink with flowers for a few miles; in the Ngobit valley 16 miles south-east of Mutara.
Flowering period varies from April to August, depending on the rains, and the locality.
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BOOK REVIEWS.
TREES AND SHRUBS OF THE KruGcER NationaL Park. By L. E. W. Codd. Memoir no. 26, Bot. Survey, Div. of Botany and Plant Patho- logy, Dept. of Agriculture, Pretoria. 1951. 7s. 6d.
This book should receive a very warm welcome, both for its own sake and as, we hope, the forerunner of a series of such books on the other biological groups—mammals, birds, reptiles, etc.—in the Kruger National Park.
It may be regarded as the first serious attempt to educate the ordinary visitor to the Park in the living organisms which are so lavishly displayed around him. It is fitting that the vegetation of the Park should be the first to receive attention, as it is fundamental to all other forms of life: and we trust that corresponding zoological handbooks will soon follow this admirable exemplar.
For the visitor the illustrations in the book are of prime importance: no keys are provided for identification—such would be almost impos- sible—and the amateur’s method of matching with pictures is the only means available of getting to know and discriminate between the host of trees and shrubs. For this purpose the large number of photographs and drawings in the book are very well suited: and having made identi- fications, the descriptions, notes, popular names (African and European), etc., given in the text will increase the interest of the intelligent visitor very greatly. These descriptions are such as to be understood by persons without special botanical knowledge, and at the same time are accurate by botanical standards. Certain groups, e.g. the Acacias and Albizzias, present special difficulties to the amateur (as to the professional botanist) and the book gives greater assistance in such cases.
The text and illustrations are printed in a uniform sepia ink on slightly tinted paper and the general effect is soft and pleasing. Six charming colour-plates by Miss Cythna Letty adorn the book. The photographs of lion and elephant are perhaps added to suggest that botanising should be done with due awareness of other forms of life. The Government Printer has gone unusually gay in the paper cover, and is indeed to be congratulated on the attractiveness of the production.
Dr. Codd deserves cordial thanks for a very noteworthy contribution to knowledge of the Park’s flora and to the pleasure and interest of its visitors whether botanical or otherwise.
R. H. Comerton.
18 The Journal of South African Botany.
PLANTS OF THE BrBte. By Harold N. Moldenke and Alma L. Moldenke. xx + 364 pp. 95 illus. Waltham, Mass., U.S.A.: Chronica Botanica
Co. 1952. $7.50. London, W.C.2. Wm. Dawson & Sons, Ltd.
To find a comprehensive book on Bible plants written by competent botanists from a critical scientific point of view is a quite unusual pleasure. As Dr. and Mrs. Moldenke remark: “Anyone delving even very super- ficially into the literature of Bible plants will be impressed at once by the amazing discrepancies, contradictions, palpable mis-identifications, erroneous statements and general confusion which exist there’. They think however that “it would be more surprising to find accuracy in botanical matters than not to find it” in the Scriptures themselves and in subsequent commentaries thereon. The Authorised Version itself is responsible for the perpetuation and origination of many of the mis- identifications of biblical plants with common English ones.
Now that the flora of the Middle East—though greatly changed since biblical times—is reasonably well known, it is possible to correct many of the popular misconceptions current among biblical students. This the Moldenkes have done in their highly efficient, thorough and at the same time readable treatise. Not only are the plants identified with reasonable certainty, but an enormous amount of relative comment is added, thus casting a most valuable and entrancing light on the whole subject of the vegetational background of the scriptural narratives. The illustrations are a most attractive feature of the book: some are photographs or drawings of the plants themselves, others illustrate biblical incidents or legends. Most charming of all is perhaps a reproduction of the elder Cranach’s Garden of Eden: and there are several other representations of the “‘apple” legend. (For “apple” should probably be read “apricot”’.)
It is unfortunate that the confusion with regard to Aloe succotrina, a South African plant, as the source of Socotra Aloes (A. Perryi or A. vera), is perpetuated. (See Reynolds in Journal S.A. Botany XIV, p- 1, 1948.) The inclusion among “Bible plants” of the organisms causing plague, ringworm, vinegar fermentation, etc., is a little surprising, but adds greatly to the general interest of the book.
“Plants of the Bible’, says the publishers’ note, “has been prepared carefully to be serviceable to interested lay- and churchmen, Bible lovers of Catholic, Jewish and Protestant faiths, scientists as well as nature- and garden-lovers.”’ In this comprehensive aim it should be eminently successful: and it is easy to prophesy a very wide appeal for what must certainly be regarded as the outstanding, because wholesomely scientific, book on the subject.
R. H. Compton.
Book Reviews. 19
Botany oF SuGar Cane. By C. van Dillewijn. Pp. xxiv + 371. 229 line drawings, photographs and diagrams. Waltham, Mass., U.S.A.: Chronica Botanica Co. 1952. $6.00. London, W.C.2. Wm. Dawson & Sons, Ltd.
This fine monograph brings into volume form the copious work that has been done on every aspect of the structure, physiology and chemistry of the Sugar Cane—a plant to which, as the author says, perhaps more research has been devoted than to any other commercial crop, largely on account of the splendid work of governmental and private experiment stations, the latter entirely run by the sugar industry. It deserves much fuller notice, in a country where sugar cultivation is one of the chief agricultural industries, than can be given here, and other journals will undoubtedly commend it to growers and manufacturers. It is written throughout with an eye to the improvement of sugar culture, and emphasis is laid on the discrepancy between efficiency in factory and in field. “Whereas in the factory,” says Dr. van Dillewijn, “every effort is made to recover as much sugar as possible, in the field only a fraction of the economical yield is obtained ...” ““The greatest possibilities of reducing the cost price of sugar are to be found in the field...” “In many cane-growing countries field practice has failed to keep pace with scientific progress, and in fact is lagging far behind.” How far these trenchant remarks apply to South Africa is not stated, and can best be judged by the very able research workers attached to the sugar industry here.
In its dignified style and the quality of its binding, paper, print and illustrations this is perhaps the most noteworthy volume that the Chronica Botanica Co. has yet produced: Dr. van Dillewijn’s deep know- ledge of his subject has been presented in a worthy form.
R. H. Compton.
MaizE IN THE GREAT HERBALS. By John J. Finan. Waltham, Mass., U.S.A.: Chronica Botanica Co. 1950. $3.00. London, W.C.2. Wm. Dawson & Sons, Ltd.
This elegantly-produced volume is mainly a reprint from the Annals of the Missouri Botanical Garden, vol. 35, 1948, handbound as designed by Dr. Frans Verdoorn, Editor of Chronica Botanica, and with a fore- word by Dr. Edgar Anderson.
In South Africa we are so familiar with the maize plant that we forget what an extraordinary grass it is. This book enables us to recapture some of the wonder of the renaissance herbalists as reflected in their woodcuts, engravings and descriptions of this marvellous plant. Mr. Finan has brought together all the early references to it, collated them,
20 The Journal of South African Botany.
reproduced the illustrations and written a very interesting account of the early history of the plant thus revealed. It would appear that at least two distinct types of maize were introduced to Europe. One was the kind brought back from the Caribbean by Columbus and _ his successors. The other presents an unsolved problem: it is probably the plant grown by the eastern North American Indians, but the herbalists believed it to have come to Europe from Asia.
Apart from being occasionally repetitive, Mr. Finan’s study is a very attractive piece of work on a limited problem, and is perhaps specially valuable in America where the Herbals are less familiar than in the European countries. It is interesting to note that it was financed by a commercial company selling hybrid corn, in spite of the fact that, as Dr. Anderson points out, the subject is of no conceivable practical value. —
R. H. Comerton.
JOURNAL OF SOUTH AFRICAN BOTANY VOL. XIX.
A NEW ALOE FROM SOMALILAND PROTECTORATE.
By G. W. REYNOLDs. (With Plate XT.)
Aloe jucunda Reynolds. Species nova. Forsitan in Sect. EUALOE Subsect. Parvae pertinet; nulli alii arcte affinis; sectionem propriam constituere debet.
Planta parva, sobolifera, mox caespitosa.
Folia ca. 12, dense rosulata, ovato-acuminata, 4 cm. longa, 2.5 em. lata, patentia vel apice recurvula, swpra viridula, parce maculata; subtus convexa, maculis numerosis parvis picta; marginibus dentibus 2 mm. longis, 3—4 mm. distantibus armata.
Inflorescentia simplex, 33 cm. alta. Racemus 13 cm. longus, 5 em. diam., sublaxe ca. 20-floribus. Bracteae ovato-acutae, 5 mm. longae, 3 mm. latae, scariosae, 3-nervatae. Pedicelli 7 mm. longi. Perigoniwm roseum, cylindricum, 20 mm. longum; segmenta exteriora per 7 mm. libera. Antherae per 2 mm. exsertae. Stigma demum 2—3 mm. exserta. Ovarium 5 mm. longum, 2.5 mm. diam.
Hab. Somaliland Protectorate: Gaan Libah, ca. 9° 55’N 44° 18’E, coll. P. R. O. Bally, no. 7157, cult. Johannesburg, fl. 31 Jan. 1953, Reynolds 6223 (type) in Nat. Herb. Pretoria.
This charming and very distinctive little Aloe was collected by Mr. P. R. O. Bally, botanist at the Coryndon Museum, Nairobi, on 2nd May 1949, at Gaan Libah, Somaliland Protectorate.
This locality is at the western end of the Golis Range about 5 miles east of Mandera (which is on the Berbera-Hargeisa road), and about 25 miles west of Upper Sheik (on the Berbera-Burau road). Mr. Bally found numbers of plants forming large clumps, 1—2 ft. across, commonly
21
22 The Journal of South African Botany.
hidden in bushes in open places on the upper edge of a dry, windswept escarpment, flowering on 2nd May 1949.
A plant sent to Kew flowered there in May 1951, when the inflorescence was preserved in liquid, but no description was drawn up at the time. When Mr. Bally’s plants flowered in Nairobi on 6th October 1951, he made an excellent life-size painting of a flowering plant and kindly sent the painting to me, together with two plants. These plants are now well established in Johannesburg, and when one of them flowered on 31st January 1953, photographs were taken, a full description drawn up, and the type material prepared for the National Herbarium, Pretoria.
A.jucunda is a most distinctive little species with rather squat, pale rose-pink flowers which, in shape and size, are allied to those of A .mcloughlinii Christian (see Fl. Plants Afr. 28: Pl. 1112 (1951)), but the latter, which comes from Diredawa in Eastern Ethiopia, is a considerably larger plant with a branched inflorescence, and entirely different leaves.
At a quick glance the clustered rosettes and leaves of A.jucunda bear a slight resemblance to those of Haworthia tesselata. The leaves of A.jucunda are flat at base with the marginal teeth more or less in the same plane, while in the upper two-thirds, the margins are somewhat involute with the marginal teeth more or less standing up at right angles to the median plane of the leaf.
When the Aloes of Tropical Africa have been more fully investigated, it is clear that affinities and groupings will have to be drastically revised. In the meantime, A.jucunda could be included under Berger’s subsect. Parvae, merely on account of its size.
Description: Plant succulent, acaulescent or with very short stem, soboliferous, forming dense groups up to 50 cm. and more across, the rosettes averaging 8—9 cm. diam., with cylindric roots.
Leaves about 12, densely rosulate, broadly ovate-acuminate, spreading to recurved, 4 cm. long, 2-5 cm. broad at base, rather fleshy; wpper surface dark green and flat low down, turning brownish and channelled in upper half, with numerous pale-green to dull-white spots throughout, the spots lenticular, sometimes confluent, smaller and more crowded low down, larger and fewer upwards; lower surface rounded, deep green, copiously spotted throughout, the spots smaller and much more numerous than on upper surface; margins armed with horny, reddish-brown, pungent, deltoid teeth up to 2 mm. long, 3—4 mm. distant, the interspaces rounded; the teeth smaller near base of leaf, largest near the middle and smaller towards apex, with a few minute spines dorsally in median line of leaf near apex.
Inflorescence simple, slender, 33 cm. high.
A New Aloe from Somaliland Protectorate. 23
Peduncle plano-convex and 5 mm. broad at base, gradually becoming terete upwards; clothed with about 6 sterile-bracts, the lowest deltoid- acute, 9 mm. long, 4 mm. broad at base, thin, dirty-white, subscarious, 5-nerved, the margins of upper half with a few minute soft teeth.
Raceme 13 cm. long, 5 cm. diam. low down, sublaxly about 20-flowered, the youngest buds suberect, grey-green striped in upper third and more crowded, the older buds spreading, with the open flowers nutant and more laxly disposed (10—15 mm. distant).
Bracts lowest ovate-acute, 5 mm. long, 3 mm. broad at base, thin, scarious, dirty-white, 3-nerved.
Pedicels lowest 7 mm. long, of a deeper pink colour than the base of the perianth.
Perianth 20 mm. long, pale rose-pink (nearest coral-pink R.C.S. 13), cylindric, basally flat or exceedingly shortly stipitate, 7 mm. diam. around the ovary, thence very slightly narrowed and slightly trigonous, the throat paler to whitish, the mouth wide open; outer segments free for 7 mm., white, with 3 pink nerves, the apices subacute, spreading; inner segments free but dorsally adnate to the outer for two-thirds their length, broader than the outer, white, with 3 congested nerves throughout, the nerves deep pink turning greenish at apex, the apices more obtuse and more spreading than the outer.
Filaments lemon-yellow, filiform-flattened, the 3 inner narrower and lengthening before the 3 outer.
Anthers in turn exserted 2 mm.
Style filiform, yellow, with the stigma at length exserted 2—3 mm.
Ovary pale olive-green, 5 mm. long, 24 mm. diam., obtusely tapering into the style.
Fig. 2. Fig. 3. Fig. 4.
Fig. 1. Plant coll. P. R. O. Bally, Gaan Libah, Somaliland Pro- tectorate, cult. Johannesburg, fl. 31 Jan.1953, x 1/3 approx.
Fig. 2. Leaf 1/1, upper surface. Fig. 3. Leaf 1/1, lower surface. Fig. 4. Flower and pedicel, 1/1.
Puate XI. Aloe jucunda Reynolds.
THE IDENTITY OF ALOE JOHNSTONII BAK. —A NEW SYNONYM.
By G. W. REYNOLDs. (With Plates XII and XIII.)
Aloe johnstonii Bak. was described in Trans. Linn. Soc. Ser. II, Bot. ii, 351, ¢. 63 (1887), and is included under “Enumeration of the plants collected by Mr. H. H. Johnston on the Kilima-njaro Expedition 1884, by Prof. D. Oliver, F.R.S., F.L.S., and the Officers of the Kew Herbarium”. The locality cited was “‘Kilima-njaro, 2,000—5,000 ft.’’, without date, or material stated.
H. H. (later Sir Harry) Johnston, in his book The Kilima-njaro Expedition published in 1886, mentions various Aloes in the neighbourhood of Kilimanjaro, and from my knowledge of that region, he had clearly seen the species later described as A. Volkensii Engler, A. lateritia Engler and A. secundiflora Engler. He does not mention a small grasslike Aloe, but he published the “Enumeration of the plants collected by Mr. H. H. Johnston on the Kilima-njaro Expedition 1884’, wherein, on page 347, is included “‘Aloe (Eualoe) Johnstoni, Baker—Kilima-njaro 2,000—5,000 ft.”. No mention of Taveta is made in Baker’s or Johnston’s account.
In his second publication, Baker in Fl. Trop. Afr. 7: 456 (1898) omits Kilimanjaro, and gives “British East Africa: Taveta, 2,000 ft., Johnston !”
Berger saw the Johnston sheet at Kew, and in Engler Pflanzenr. Liliac.-Aloin. 167 (1908) he quotes ‘Kilimanjaro: Without precise locality, 2,000—5,000 ft.’’.
Mr. E. Milne-Redhead informs me that there is no date stated on the sheet, that the locality given is “Taveta, 2,000 ft.”, and that there are no other notes on the sheet.
From his text and maps, it is clear that Johnston had been to Rombo, and was also at or very near the places now known as Marangu, Himo and Moshi (2,700 ft.), as well as Taveta (2,525 ft.) which is in Kenya Colony, 2 miles east of the Tanganyika border, 9 miles east of Himo and 26 miles east of Moshi.
It seems that A. johnstonii could have been collected somewhere between Moshi and Rombo, on lower grassy slopes of foothills lying to the south-east of Kilimanjaro, rather than near Taveta which is in drier country with less grass and more thorn.
I have not seen specimens from that region, but I have examined material collected by Mr. P. R. O. Bally, botanist at the Coryndon
25
26 The Journal of South African Botany.
Museum Nairobi, on the nearby Chyulu Hills to the north-east of Kilimanjaro. This proved to be conspecific with the South African species A. myriacantha (Haw.) R. & S. from the Zuurberg, near Grahamstown, in the Eastern Province of the Cape.
On 6th May 1952, accompanied by Mr. Bally, I examined numbers of flowering plants in wet grasslands near the eastern boundary of the Royal Nairobi Golf Course, and more near Langata, about 5 miles south- west of Nairobi. These plants were unquestionably conspecific with the Chyulu Hills species, and in no characters could they be separated from A. myriacantha of the Cape.
For these reasons A. johnstonii cannot be upheld as being specifically distinct from the earlier described A. myriacantha and consequently should go into synonymy.
In the South African and East African plants the narrowly linear leaves are dorsally obtusely keeled, which is a character unfortunately omitted from the description in Aloes S. Afr. 116 (1950).
It is not necessary to describe the species again, but the synonymy will now read:
A. myriacantha (Haw.) R. & S. in Syst. Veg. 7: 704 (1829); Kunth. Enum. pl. 4: 516 (1843); Baker in Journ. Linn. Soc. 18: 156 (1880), in Th. Dyer FI. capens. 6: 306 (1896): Schonland in Rec. Alb. Mus. 1: 35 (1903); Berger in Engler Pflanzenr. Liliac.-Aloin. 166 (1908); Reynolds in Journ. S.A. Bot. 13: 100 (1947), in Aloes 8. Afr. 116
1950).
ial Bobi myriacantha Haw. in Phil. Mag. 122 (1827).
— Leptaloe myriacantha (Haw.) Stapf in Bot. Mag. t. 9300 (1933); Christian in Fl. Pl. S. Afr. 20: Pl. 799 (1940).
— Aloe johnstoni Bak. in Trans. Linn. Soc. Ser. 2, Bot. 2, 351, t. 63 (1887), in Th. Dyer Fl. Trop. Afr. 7: 456 (1898); Durand et Schinz Consp. Fl. Afr. 5: 308 (1893); Engler Pflanzenw. Ost-Afr. 140 (1895); Berger in Engler Pflanzenr. Liliac.-Aloin. 167 (1908); Reynolds in Journ. S.A. Bot. 13: 100 (1947).
The following is the distribution as at present known:
South Africa: Grahamstown, Port Alfred, East London. Zululand: near Richard’s Bay.
Southern Rhodesia: Inyanga Downs.
Tanganyika Territory: Kilimanjaro; Bukoba Dist., Kiboroga steppe north of Kagera (c. 1° 10’S 31° 20’E).
Kenya Colony: Chyulu Hills, Machakos, Nairobi, Ngong.
Uganda: The following material is in Herb. Kew.: Ankole: Gayaza. 5,000 ft., May 1929, J. D. Snowdon 1912; E. Ankole, Sanga Rest Camp, 4,400 ft., Oct. 1932, W. J. Eggeling 593; Ankole, Mbarara, 5,000 ft.,
The Identity of Aloe johnstonii Bak.—A New Synonym. 27
March 1939, J. W. Purseglove 654. This represents a range of almost 3,000 miles, and is the widest at present known for any species of Aloe in Africa.
In South Africa A. myriacantha flowers once a year, in April. In East Africa and Uganda plants flower after the rains, from March until October according to locality, and it appears sometimes more than once a year.
Two plants collected near Nairobi when flowering there on 6th May 1952, flowered in Johannesburg in November 1952, and again in March 1953.
In am indebted to the Director and to Mr. E. Milne-Redhead of Kew for a duplicate illustration of the drawing of A. johnstonii used for t. 63 in Trans. Linn. Soc., for notes on the type material of A. johnstonii, and for the Uganda citations.
‘ wi deer: nt af!
ip 7 - H lh } eS : Dis “rarie F Huo ohial iS ny
or id. ; rf via
AL ve t as a Vy DM tty 7 Be
ian na rf af ond ail Aut
lal
Trans Lise Sot. Sen 2 Bot You th & 83
DNagre Fak oe
Baker
ALDE JDHMSTON: .
Fig. 1.
Prate XII. Aloe myriacantha (Haw.) R. & S.
).
north-east of Kilimanjaro, Kenya Colony.
7
2, t. 63 (188
Bot.
s. Linn. Soc. Ser. 2,
| Fig. 1. The figure of A. johnstonii Bak. in Tran
April, 1938, on the Chyulu Hills,
aterial collected by Mr. P. R. O. Bally,
Photo P. R. O. Bally.
2. M
Mig.
Fig. 2. Prate XIII. A. myriacantha (Haw.) R. & 8.
Fig. 1. Plant « 1/3, fl. 6th May, 1952, Royal Nairobi Golf Course. Fig. 2. Raceme 1/1, from a plant fl. 6th May, 1952, Langata, near Nairobi. Fig. 3. Flowers 1/1, from bud to fruit stage, Langata, near Nairobi.
Hig. 3.
A NOTE ON SEX IN ROYENA GLABRA L. (EBENACEAB).
By Captain T. M. Satter, R.N. (RET.).
The small shrub Royena glabra L. is widely spread in the Western Province and is particularly common on the slopes in the northern part of the Cape Peninsula. In the description given by Hiern in Vol. IV § 2, p. 457 of the Flora Capensis the flowers of this plant are said to be hermaphrodite or polygamous; the anthers about ;’5 in. (approximately 2 mm.) long, not always fertile; the fruit globose or oblong, 4 to 3 in. (8—17 mm.) long, purple or reddish, and the seed spheroidal, black.
I was recently asked to collect some seeds of this Royena for growing in the famous gardens of Tresco Abbey in the Scilly Isles and was at once struck by the fact that only a small proportion of the bushes bore fertile fruit. These fertile fruits are oblong or oblong-ellipsoid, usually 13—18 mm. long and 6—9 mm. in diam., at first green, then turning to deep reddish plum colour and are finally black and wrinkled before falling. Very rarely a deformed fertile fruit may be found which approaches spherical in shape. The seed, freed from the pulp, is ellipsoid or oblong- ellipsoid, extremely hard and shining chestnut brown, usually solitary, often 1—1-5 cm. long and 4—5 mm. in diam., but occasionally found in adpressed pairs, with the adjacent faces flattened.
Most of the bushes bear no fruits at all, while others produce a few, or more rarely many small abortive, almost spherical fruits, usually 4—7 mm. long, which produce no seeds. These abortive fruits sometimes persist on the plants during the following flowering season. Both abortive and fertile fruits are puberulous.
These observations suggested that the flowers of this species were possibly dioecious for, though a large number of bushes were examined in the neighbourhood of Kirstenbosch and Wynberg Hill, no fertile fruits could be found on the suspected male plants, although they were usually copious on the supposed female plants.
Later, in the flowering season, the flowers of certain marked plants were examined and it was found that the anthers of the supposed ¢ plants, including those bearing abortive fruits, varied from 2—3 mm. in length and bore copious pollen, whereas the anthers of the plants which bore fertile fruits were only 1 mm. long or less, and entirely devoid of pollen. Furthermore, the flowers of many more plants examined in the field showed that the sex could be at once determined by the marked difference in the size of the anthers. The comparatively few, suspected as 2 from the small anthers, have been found later to be producing fertile fruits. The ovary
29
30 The Journal of South African Botany.
of the 3 contains + ovules and appears to be indistinguishable from that of the flowering 2. The styles, too, in both seem to be identical. At this stage, therefore, the flowers might easily be taken for hermaphrodite.
An examination of bushes on the slopes near the northern boundaries of Kirstenbosch in February 1953 revealed that out of 19 adult bushes examined, only 2 bore fertile fruits.
To avoid any suspicion that perhaps a local form or variant of R. glabra may occur in the limited area investigated, the flowers of 16 herbarium specimens from the Provinces of Caledon, Ceres, George, Knysna, Paarl, Piketberg, Tulbagh and Worcester, were dissected, and inspection of the anthers showed that 13 were male and only 3 female.
SUMMARY.
It seems. therefore. beyond question that the flowers of Royena glabra are dioecious and that the bushes are definitely either 3 or 9, the 3 plants predominating. The important discrepancies in the description in the Flora Capensis may be summarised as follows:—
Organ. As described in Flora As observed in many living Capensis. and dried plants. Flowers .. xs .. | Hermaphrodite or poly- | Dioecious. gamous. Anthers .. . | About 2 mm. long, not | g 2—3 mm. long, fertile. always fertile. 2 0-7—1 mm. long. sterile. Fruits 8—17 mm. long 3g 6—7 mm. long, abortive,
rarely developed. 2 13—18 mm. long, fertile. Seed ze So .. | Spheroidal, black .. | Ellipsoid or oblong-ellipsoid, shining, brown.
It is presumed that the descriptions of Royena given by Mr. Hiern in the Flora Capensis were all made from the study of dried specimens only, and the facts here recorded from field study reveal the difficulties with which the purely herbarium systematist has to contend. In the case of R. glabra, he has cited 37 collectings and apparently not been able to arrive at the true facts. It is noteworthy, also. that of the other 16 species described in the Flora Capensis, only one collecting is cited in the case of 6 species and only two or three for 4 others. While it is true that in 4 of these cases the sex of the flowers is not specified definitely and the term subdioecious is used freely in this respect. it seems that full field observa- tion might reveal much that is at present unknown about the sex question in this genus. The casual collecting of individual specimens, whether in flower or in fruit. proves to be of little help in this direction.
ACKNOWLEDGEMENT.
I gratefully acknowledge the help given to me by Dr. M. R. Levyns in the microscopic examination of the anthers.
KARYOLOGICAL STUDIES AND CHROMOSOME NUMBERS IN HYPARRHENIA AUCTA AND H. HIRTA.
By Steran Krupxko, Ph.D. (Warsaw). (With Plates XIV, XV.) INTRODUCTION.
The area of distribution of Hyparrhenia hirta is extremely extended. It covers the whole continent of Africa, especially its eastern side, with only a few breaks. It passes even to Western Asia. In the Union it was recognised quite long ago as an important species for soil conservation. However, the use of this grass in eroded areas has been restricted because of the low germinability of its seeds.
Plant ecologists and grass breeders found that the above species includes two or three forms without sharp and distinct differences amongst them.
The present paper deals mostly with these two problems. Its aim is to find the causes of the partial sterility in Hyparrhenia hirta and reveal the karyological differences, if any are present, among the morphological forms.
TECHNIQUE.
In order to have material for cytological investigations one first must get seeds for germination.
In the beginning of this work soaking of collected seeds in 95 per cent Alc. was often used in order to separate easily empty scales and florets from fertile seeds. To check the influence of this treatment on root mitosis and on the germination of seeds, a small series of experiments was carried out with different times of treatment compared with untreated control samples of the same samples of seeds. It was found that 5’ or even 10’ treatment of florets with 95 per cent Alc. had no influence on the root mitosis, but definitely affected the germination. Thus to be on the safe side when this treatment was used, the material was soaked for 5’ and afterwards the florets were transferred to water for 15’—30’. Subsequently fertile seeds were selected under a dissecting microscope using needles.
To obtain adventitious roots from mature plants dug from the soil the following method was used. The leaves and stems were cut to a height
31
32 The Journal of South African Botany.
of 10—15 em. above soil level and smaller roots were also cut. The plants were then soaked overnight or for 24 hours in a Hortomone solution of the concentration: 14 cc. of Hortomone to | pint of water. Next the plants were placed between sterilised wet blotting paper in sterilised dishes and the dishes then placed in a thermostat at + 40°C. On the tenth day usually the first adventitious roots appeared. It was found that the treatment with Hortomone did not affect the mitosis. Shorter soaking, for example for 4 hours also had no effect on germination, but stronger concentrations of Hortomone gave less satisfactory results.
Often plants were potted out in soil after such treatment and gave a good crop of young roots in 1—2 weeks’ time. Most of the root tips for microtome technique were fixed mainly in two fixatives:
I. Navashin fixative, Stockholm modification (see Maheshwari, 22). Liquid A: Chrom. acid—1l gm., glace. Acet. ac.—l0 cc., water— 65 ce. Liquid B: Commercial formalin—40 cc., water—35 cc. Before use equal volumes of A and B are mixed. Il. Levitsky fixative (Avduloy, 2).
The best results were obtained with a modification of the above fixative. Equal parts of the following solutions were mixed: (a) 4 per cent formol; (6) 2 per cent Chrom. acid. The material was infiltrated for 15’ with this mixture. using a pump.
For staining microtomed material Newton’s Crystal Violet stain was used after Navashin’s fixative. Adventitious root sections were stained for 30’ and differentiated in Lugol for 30”. Primary root sections were stained for 20’ and differentiated in Lugol for 35”. These times of staining were the best to bring out chromosome morphology, but for counting deeper staining was preferred. and the time required for differentiation was shorter—20”. Another modification of value for morphology was: staining 15’, Lugol 30—32”. For the above staining techniques the most satisfactory thickness of sections was 10 mu. After the treatment with Levitsky fixative the material was stained with Iron Hematoxylin. Before staining the mordants used were: (a) three days’ treatment in | per cent Chrom. acid followed by short washing in distilled water and transferring to (6) 6 per cent alum solution for 24 hours. The thickness of sections here was 7—8 mu.
FEULGEN METHOD. MopDIFIED:
After the use of Navashin fixative the Feulgen method of Warmke’s (45) modification for squashing of isolated sections and isolated cells with metaphase was used. Slides with root tip sections (thickness 8 mu.) were hydrolised in N HCl for 45’ at 60°C. Next followed staining in
Karyological Studies and Chromosome Numbers in 33 Hyparrhenia aucta and H. hirta.
leucobasic fuchsin for 3 hours, then—mounting in dilute balsam. Squashing of the sections was advisable only on the second to third day after mounting. With this method it was possible to squash sections and to spread the chromosomes in 3 slides of H. hirta (7.VI1.48—11.X.48). The counting was 2n = 44. This squashing method was a difficult and laborious process. It was noted that: (a) squashing was impossible on the sixth or seventh day after mounting, and (b) that in a few months’ time the chromosomes lost their colour.
SeuasH Merrnops:
There are some difficulties in the staining of pollen grain mother cells which are not easy to explain. The best results were achieved in the following procedure with the anthers:
1. fixation in 1 p. of glacial acetic acid and 5 p. of absolute alcohol.
2. 3 days in aceto-carmine.
3. mounting in 45 per cent acetic acid, with slight heating, followed by squashing and immediate mounting in Euparol.
With direct squashing in aceto-carmine it was difficult to obtain good spreading as well as good staining. It was helpful to use aceto-carmine mixed with 4 per cent Iron Acetate as follows: 1 drop of Iron Acetate added to 10 cc. of aceto-carmine. The mixture must be prepared fresh nearly every day.
Sometimes good results were obtained by using carmine saturated in glacial acetic acid instead of solution 1.
Snamt SromacH Juice (Fabergé, 10):
The sections prepared from fresh root tips were fixed (acetic alcohol) and then passed to 70 per cent ale. Next, the sections were passed through alcohol and water changes and left in snail stomach juice for 5} hours at + 40°C. Afterwards sections were washed in water, mounted in a drop of aceto-orcein, heated and squashed. They had been left in aceto-orcein for 20’. Sometimes it is necessary to use an additional 1—4” of heating during the staining.
The active substance here is probably cytase and the best source of it is the edible snail—Helix pomatia. We used the South African relatives of this genus with very good results. The process of dissection of the snails and of extraction of juice is, however, troublesome and time devouring.
ProtinoL MetHop (MacKey and Clarke, 21):
Pectinol in 1 per cent watery solution may be used at room temperature or at temperatures not exceeding 49°C. Entire roots may be treated or
34 The Journal of South African Botany.
sections of root tips previously fixed, passed through the alcohols and washed carefully in water. Then the above sections were transferred to 1 per cent pectinol for 5—6 hours at 40°C., or for 15—17 hours at room temperature. Finally they were washed in water, mounted in a drop of aceto-orcein (or aceto-carmine), squashed and stained.
The roots preserved for a long time in 70 per cent alcohol require more complicated treatment as follows: 1. prepare hand sections, 2. transfer for 1—14 hours to the Warmke liquid (equal parts of N HCl and 95 per cent alcohol) at 58°—60°C., 3. pass sections quickly through 95 per cent alcohol, and then gradually bring down to water, 4. change water, 5. leave sections in 1 per cent pectinol for 24 hours at room temperature, 6. pass through water, squash and stain with aceto-orcein.
GERSTEL METHOD (12):
The original Gerstel method, when properly modified for difficult grass roots, gave quite good results with regard to counting of the chromosomes. Here again entire root tips or sections can be treated. With Hyparrhenia hirta it was found preferable to prepare sections from the fresh living roots which were immediately fixed. The procedure was as follows: 1. fixation in cold 10 per cent N HCl and infiltration for 15’, 2. transfer sections in the 10 per cent N HCl to the thermostat at 58°C. (or 60°C.), for 1 hour and 30 minutes, 3. 95 per cent alcohol for 4—1 minute and transfer to aceto-orcein mixed with HCl (in the proportion of 1 ee. N HCl + 10 cc. aceto-orcein), 4. aceto-orcein + N HCl for 1 hour, 5. transfer to a drop of pure aceto-orcein, heat and squash. This procedure was found to be necessary for difficult roots like those of H. hirta. Applied to other plants, the procedure may be simplified when, for example, the transfer to 95 per cent alcohol may be omitted, aceto-orcein may be used without HCl, and the times may be shortened.
O'Mara MetuHop (32):
This method gives very distinct staining of resting nuclei (chromo- centers) and prophase stages. Metaphase chromosomes were, however, rather difficult to stain properly. Fresh root tips or sections of them are treated as follows: 1. 3 per cent methanol for 3 hours, which is then replaced by the following fixative: methanol—65 parts; chloroform—5 parts; glacial acetic acid—30 parts; 2. leave in the above fixative for 13 days (other plants require only 3 days, e.g. Kniphofia roots): 3. transfer to a drop of aceto-orcein (which may be used with N HCl as described under Gerstel’s method) or to fresh aceto-lakmoid; 4. squash and heat at least twice; 5. stain 5—10’.
Karyological Studies and Chromosome Numbers in 35 Hyparrhenia aucta and H. hirta.
Leucopasic Fucusin SquasH MeErHop:
Root tips are fixed in acetic alcohol for not less than 2 hours. Two modifications were used:
A. Sections of the fixed material were treated as follows:
1. In 1 per cent pectinol for 4 hours at 40°C.; 2. quick washing in water; 3. hydrolysis in N HCl at 60°C. for 1 hour; 4. long staining in LB-fuchsin (up to 12 hours); 5. squashing in a drop of LB-fuchsin.
B. Sections were treated as follows:
1. In 4 per cent NH,OH at 60°C. for 15’; 2. transferred to N HCl for 14 hours at 58°C. or 60°C.; 3. long staining in LB-fuchsin (from 3—12 hours); 4. squashing in a drop of LB-fuchsin (or a drop of 45 per cent acetic acid).
Many modifications of above squash methods are useful only for counting the chromosomes. One must always remember that aceto-orcein causes much more swelling of the chromosomes than aceto-carmine. With the LB-fuchsin squash method chromosomes are not swollen but they stain rather faintly. For the morphology of chromosomes in Hyparrhenia hirta the squash technique is useless.
The chief aim of this chapter is to save grass cytologists much time and trouble as it is the writer’s hope that his experience will be useful for future grass investigations in South Africa.
MeEIotTic CHROMOSOMES, NUMBERS AND BEHAVIOUR.
The investigation of meiotic chromosomes (bivalents) in both 1-meiotic metaphase and in diakinesis was done mainly in two ways: (a) with varia- tions of the squash method and (6) with material fixed in Navashin liquid and Carnoy and sectioned on the microtome. The details of the techniques and difficulties met with have been described in the previous chapter. The results will now be given. From the commencement of this work with Hyparrhenia hirta (strain 2n = 44) in early 1944, it was clear that the plant is extremely variable in number of chromosomes in pollen grain | mother cells and rich in many irregularities during disjunction. The species always gives difficulties in squashing and staining with aceto- carmine and with other aceto-methods. It was first thought that the variable numbers in the haploid set might have been due perhaps to very hot and dry weather in April, May and June, 1944, but when material was collected in a wet season in the following year the results were the same. It was soon found that observations on the valents association in diakinesis are very uncertain due to the smallness and indistinctness of bivalents.
36 The Journal of South African Botany.
TEXT FIGURE 1.
Fic. 1.—H. aucta. Root tip metaphase with 2n = 20. Fixation—Levitsky (5:5) with 4% formol, 1% chrom. acid 3 days. Stained—iron haematox. Thickness 7 p. B. & L. Fl. oil immers. x 98 and Comp. oc. x 10. Magnification + 1400 x.
Fic. 2 to Fic. 5.—Drawn with B. & L. Fl. oil immers. x 98 and comp. ok. x 15. Magnification + 2800.
Fic. 2.—H. hirta, root tip metaphase with 2n = 44. Fix—Levitsky (5:5) with 10% formol, 1% Ac. Chrom.—3 days. Stained—iron haematox. Thickness 7 p.
Fic. 3.—H. hirta from U.S.A., adv. root tip metaphase with 2n = 30. Fix.— Navashin. Staining—Crystal Violet. “‘S’’-like chromosome present.
Fic. 4.—H. hirta from U.S.A. 2n = 30. All conditions as above. “S’’-like chromo- some absent.
Fic. 5.—Schizochyrium semibarbe from Frankenwald (from the field numbered in 1945—P4). Fix.—Levitsky (5:5) with 10% formol. Stained—iron haematox. Thickness 8 p. Root tip metaphase, 2n = 50.
Fic. 6.—Optics as Fig. 7. Tubes 0. Decreased-magnification + 750 x. Stained as Fig. 7. Enormously big diads. Resting nuclei. Laggers in cytoplasm still persistent.
Fic. 7.—H. hirta, 2n = 44. P.gm.c. Acetocarmine squash. Leitz, big microscope.
B. & L. oil Immers. x 97, comp. ok. x 10. Tubes 160. Magnification + 1700 x. First metaphase; n = 22.
In December, 1945, 22 bivalents (Pl. XIV, fig. 4, Text-Fig. 1: 7) were obtained in about half the number of pollen grain mother cells investigated, both in freshly squashed and in microtomed material. It was, however, impossible to state anything definite on their morphology. The rest of the metaphases showed the following numbers: 20, 18 (Pl. XIV. fig. 5), 16 (very rare), 14 (Pl. XIV, figs. 2 and 3 give the same diakinesis taken in two levels). Even numbers were usually found in these observations and odd numbers, e.g. 21 and 17, were rarely found. From the beginning of these observations many laggers (Pl. XIV, photo. 6) were evident in
Karyological Studies and Chromosome Numbers in 37 Hyparrhenia aucta and H., hirta.
anaphases. They were found in every season, in material collected in moderately warm weather in December (PI. XIV, fig. 8), as well asin a very hot period during February and March. It was thought important to determine exactly whether the laggers were included later in the daughter nuclei or whether they persisted in the cytoplasm during the telophase and what was the final fate of these bodies. In anaphase they were found in various positions in relation to the poles and the equator, as well as in very variable numbers. Numerous small laggers were present on the equator (Pl. XIV, fig. 6) in the beginning of anaphase. They were also present in the middle telophase (Pl. XIV, fig. 7) approaching one of the daughter nuclei, sometimes from two directions. In some cases they were arranged in one line between two daughter nuclei during late telophase (Pl. XIV, fig. 8). In squash aceto-carmine slides they could be found in different stages, for example in diads (Text-Fig. 1; 6). In tetrads they were very distinct, either like separate chromosomes (Pl. XIV, fig. 9), considerably decreased in size, or organised into dwarf nuclei (Pl. XIV, fig. 11). In very young pollen grains with | nucleus, before the formation of the exine, they have been seen either single (Pl. XIV, fig. 10) or even as many as four (Pl. XIV, fig. 16).
This was the last stage in which they were observed and in older pollen grains they are not present.
Probably they are later absorbed completely by the cytoplasm as they are never found subsequent to the 2-nucleated stage in pollen grain development.
Nevertheless, the accumulated evidence shows clearly that abundant lagging can be the cause of variable and small chromosome numbers in first meiotic metaphase. Persistence of the laggers through all the stages of pollen grain development including 1-nucleated pollen grains shows that deficient chromosome numbers can not be readjusted and that they are present in pollen grain nuclei as well.
In the light of the above facts we can consider the lagging of chromo- somes in the first meiotic metaphase as a chief cause of deficient chromo- some numbers in male gametes and as a chief cause of partial sterility of seeds in this strain of Hyparrhenia hirta.
Mature PoLueEN GRAINS AND THEIR GERMINATION.
The first attempt to investigate mature pollen grains of Hyparrhenia hirta (strain 2n = 44) showed that the task would not be easy. From the beginning of this work in 1944 and 1945 a high percentage of degenerated and shrunken pollen grains were found; these had an extremely distorted abnormal shape and in many cases it was clear that they were empty, containing neither cytoplasm nor nuclei. The same has been recently
38 The Journal of South African Botany.
observed in Anthoxanthum by Lima de Faria (20), who considered it to be an indication of a high degree of disturbance in meiosis and a sign of extreme degeneration. It was estimated that in 1944 and 1945 there were approximately 20 per cent of degenerated pollen grains in each anther. An attempt was made to germinate the pollen grains using different con- centrations of saccharose with agar and gelatine according to H. E. Newcomer's prescription (31). Different types of water were used in the preparation of the media: (a) distilled water: (6) Johannesburg Munici- pality tap water and (c) well water from Frankenwald. Keeping in mind Brink’s observation (4) that pH —7 is optimal for the germination of pollen grains, the pH of Johannesburg tap water was determined, and was found to be 8-0. Accordingly some of the media were acidified slightly but no success was obtained.
Swelling of pollen grains was observed, and sometimes they actually exploded, but usually not much development was seen. After application of a 40 per cent concentration of saccharose a few tubes were observed, but they were usually very short and soon died.
Artschwaeger and Maguire (1) have recently used the same concentra- tion with success for pollen grains of Sorghum vulgare. In this species the pollen grains started to germinate 15’ after sowing and the growth of the tubes continued for 3 hours. H. hirta, in spite of being a member of the same tribe Andropogoneae, behaved quite differently.
Nevertheless, from these unsuccessful preparations of the tubes some important observations were made, not on germinated pollen grains but on those swollen enough to give a clear picture of their nuclei after staining by Newton’s crystal violet method.
The mature pollen grain is 3-nucleated, as is usual in the Gramineae (except in the case of degenerated pollen grains). Pollen grains with 4 nuclei (Pl. XIV, fig. 12) were found three times on slides stained with crystal violet and twice in temporary aceto-carmine squashes (5.6.44). Once even a 5-nucleated pollen grain was seen (Pl. XIV, figs. 14 and 15).
This matter has been given a fair amount of attention in recent literature. Thus de Mohl (24) described 4, 5, 6 and even 7-nucleated pollen grains in Hyacinthus plants, the bulbs of which had been accelerated in their growth. Apart from these there were some giant pollen grains which the author considered to be diploid. According to de Mohl pollen grains with supernumerary nuclei obtained their additional nuclei from the division of generative nuclei. In his opinion they are supernumerary male gametes and are fertile and compatible. The writer feels, however, that there is not sufficient evidence for this view. On the other hand, La Cour (18) in Tradescantia bracteata, and K. Sax in Tradescantia virginica (38) found pollen grains with supernumerary nuclei after special
ID1 OGRAM OF HYPARRHENIA CHROMOSOMES. ~ x2800.
H. aucta. JU UU vu ve ow LA ffs eas
Hoh. 2n=44
WY UL uu UU vw vy ow we Sf WU Cee fe a I. 2. Fist h 5. 6. 7. 8. g. ioe > ik 12. 3. \%, IS. 6. (7 18. 19. 20. 1 a © ©
H.h. 2n= Jo.
VV UY VY wu wy UY KA Ll the ge 6 ee ii aé a6 i a. : 7. 8. lo. it. Bo TB. 1% 15. 7. 2o.
—
Karyological Studies and Chromosome Numbers in 39 Hyparrhenia aucta and H. hirta.
treatment with heat. These investigators considered they were derived from the additional mitosis of generative nuclei and supposed them to be fertile. The former author also counted the normal number of chromo- somes in supernumerary nuclei (n = 6). Lima de Faria (20, p. 540—543) found pollen grains with supernumerary nuclei in Anthoxanthum and proved that they were derived from tube nuclei (except in one case in which there were two additional mitoses in both tube and generative nuclei). He considers the possibility that they are the result of degeneration.
Artschwaeger and Maguire (l.c., p. 664) found supernumerary nuclei in pollen grains of Sorghum vulgare, which they claimed were derived from generative nuclei.
K. Sax (39) in Tradescantia and Upcott (43) in Belladonna found some pollen grains with supernumerary nuclei from tube nuclei in triploid strains. They regard this occurrence as a result of unbalance in chromo- some numbers in meiosis of triploids and suppose them to be infertile.
In all the five described cases of supernumerary nuclei in H. hirta there was no distinct evidence as to the source from which the additional nucleus of the pollen grain is derived, as mitosis has not been observed. The only evidence of their nature could be found in their different ability to take up stains as compared with normal pollen grains, as they stain like abnormal nuclei.
Summing up the observations on the mature pollen grains the two following causes of partial sterility in H. hirta should be added to those given:
(a) degeneration of pollen grains; (b) occurrence of pollen grains with supernumerary nuclei.
In a test of the viability of pollen grains with N.R. (neutral red— A. Guilliermond) in general all except degenerated and deformed ones were found to be still alive in spite of their inability to germinate in artificial media.
The normal mature pollen grains of H. hirta are very rich in starch as shown by their reaction with Lugol.
CHROMOSOME MorRPHOLOGY AND CHROMOSOME SET.
The following method was used to investigate the morphology of chromosomes in detail. Five to ten of the best metaphase plates in root tips were selected and drawn as exactly as possible with a Zeiss drawing apparatus and at the same magnification, approximately 2,800 x. Next the chromosome drawings were cut out with scissors and arranged in a row on a sheet of cardboard in such a way that the bases of the chromo- somes were on the same level. Homologous pairs were arranged according
40) The Journal of South African Botany.
to their heights in descending order so that the longest pair in each group was on the left and the shortest on the extreme right of each group. The conventional grouping was followed, namely, on the left the “V”- shaped chromosomes: next to them the “L-shaped ones and lastly the rod-shaped pairs. In this way all homologous pairs of the same height were arranged approximately on the same vertical line. Having drawn all the best metaphase chromosomes and placed them on one sheet of paper the average diagrammatic pair was prepared from them for each vertical row of pairs.
The diploid set of such diagrammatic pairs forms an idiogram of the chromosome set (a term introduced by S. Navashin (27)) and its method of use can be found in older literature (vide L. Delaunay’s paper on Muscari (8) and more recently Taylor’s paper on chromosomes of Aloe, Gasteria. Haworthia (41, 42) and M. Navashin on Crepis (28)). Having prepared idiograms for H. aucta and for two strains of H. hirta the task of comparing them became much easier (see idiograms Text figure 2.) The diploid set of chromosomes in H. aucta was 20 (Pl. XIV, fig. 1, 17: Text-fig. 1; 1). The chromosomes were bigger and a little wider than the chromosomes in both strains of H. hirta. In H. aucta the haploid number was 10 (counted by Mrs. E. Gluckmann, unpublished). In meiosis of H. aucta no abnormalities were observed and there is no difficulty in assuming a basic number of 10 in H. aucta as this is a rather frequent basic number in the Gramineae. We can easily see from the idiogram (see Text-fig. 2) of the diploid set of H. aucta that it consists of the following kinds of chromosomes:
(a) One pair—the largest chromosomes—“V’’-shaped with unequal arms and with two constrictions; one on the larger arm and the second on the tip of the “V” angle;
(6) three “V-shaped pairs with equal arms;
(c) one “V’’-shaped pair with unequal arms, a single median con- striction and a very obtuse angle. This pair might as well be described as “L’’-shaped:
(d) three “L’’-shaped pairs;
(e) one “S’’-shaped pair;
(f) one short rod-shaped pair with median constriction.
A more detailed analysis of this idiogram shows three “V-shaped pairs with equal arms consisting of different morphological pairs, having in common only the shape similar to a “V” and equality of the arms. The second pair from the left on the idiogram has two constrictions; one median (on top of the “V” angle. the kinetochore), and the second constriction on the arm. Also this pair is the largest amongst the “V-shaped with the equal arms mentioned under (8).
Karyological Studies and Chromosome Numbers in 41 Hyparrhenia aucta and H. hirta.
The next pair on the right side is a much smaller one but is dis- tinguished from the preceding pair not only by its size, but also by having only one median constriction. The next pair on the right (the fourth on the idiogram from the left side, text figure 2.) is smaller again, with the single median constriction. It is distinguished from the two pairs mentioned previously under (+) by its very obtuse angle. The three ““L’’- shaped pairs mentioned above under (d) also show variation in their characters. It is possible to distinguish fairly easily (1) one big “L’’- shaped pair with the 2 constrictions, both on the longer arm; (2) two much smaller ““L’’-shaped pairs with the median constrictions.
Summing up the morphological features of the chromosome set in H. aucta we can say that it is easily recognisable not only by the number of 20, but also by the presence of such types of pairs as the “‘S’’-shaped pair, the big “V’’-shaped with unequal arms, and a single short rod-shaped pair with median constriction.
In H. hirta the author found two strains respectively with 2n — 30 and 2n = 44, growing sometimes very near each other.
The diploid set of 2n = 44 may be described first (see the idiogram text fig. 2, Pl. XIV, fig. 18, 19, and Text-fig. 1; 2, 3, 4, in this connection).
Here we can recognise the following groups:
(a) Seven “V”-shaped pairs with equal arms;
(6) one “V’’-shaped pair (N2) with unequal arms and two constric- tions, one on the bigger arm and a median one;
(c) one pair “S’’-shaped (N9);
(d) seven “L’’-shaped pairs;
(e) six rod-shaped pairs.
In describing in detail the morphology of the above set it will be noticed that amongst these ““V’’-shaped pairs with equal arms the following types will be found:
(1) the largest “V-shaped pair which has either two or sometimes even three constrictions. In the majority of metaphasic plates the constrictions were two in number with usually one on the bigger arm and one (probably the kinetochore) in the median position ;
(2) a smaller pair than the previous one (N3) with two constrictions on both arms;
(3) two still smaller pairs (N4 and N5) with median constrictions but differing from each other in size;
(4) three pairs, again smaller (N6, 7, 8) differing from the above described groups under (1) to (3) by their distinctly obtuse angle. For example, pair N8 could be described as a small “L”- shaped pair because the chromosomes have a very obtuse angle.
42 The Journal of South African Botany.
In the group of “L-shaped chromosomes (mentioned under (d)) there are the following types:
(1) four “L’’-shaped pairs (N10, 11, 12, 15) differing markedly in size with two constrictions each. The secondary constriction is usually found on the bigger arm while the kinetochore usually has a median position. The pair N11 sometimes shows 2 con- strictions on one homologous chromosome and one on the other. This is due, possibly, to insufficient differentiation:
(2) three smaller “L”’-shaped pairs (N13, 14, 16) have one median constriction. They differ less in size amongst themselves than those of the former group.
Under heading (e) six rod-shaped pairs have been listed. Amongst them we can distinguish two types: ~
(1) three rod-shaped pairs with one subterminal constriction (N17, 20, 22); and
(2) three rod-shaped pairs with one median constriction (N18, 19. 21).
The morphology of the last group was very difficult to determine due to the smallness of the chromosomes. The pairs number 20, 21 and 22 are the smallest of the set and it was sometimes difficult to decide whether the constriction was really subterminal or median.
The H. hirta strain with 2n = 30 chromosomes has a diploid set consisting of the following groups: (a) five “V-shaped pairs (N1, 4, 6, 7, 8) with equal arms; (6) one “V”’-shaped pair with unequal arms and two constrictions; (c) six “L”-shaped pairs; and (d) three short rod-shaped pairs.
In comparing this set with the former strain (2n = 44) we can note without difficulty a striking similarity between the two sets. The 2n = 30 strain simply has a set of 2n = 44 strain chromosomes less seven definite pairs. These missing pairs are:
(a) N3 and N5 pairs from “V”’-shaped groups with equal arms; (5) the “S’’-shaped pair:
(c) the smallest N16 pair from the “L’’-shaped group;
(d) three pairs N18, 19, 21 are absent from the short rod group.
In other words, all the chromosomes in the above group which have median constrictions are absent, and all the short rod-shaped chromosomes with subterminal constrictions are present.
As a result of this study it was found easy to recognise roots of H. hirta, 2n = 30 strain, without counting the chromosomes.
The metaphase plates were better spread and the chromosomes less crowded; the absence of the “S’’-shaped pair (N9) was easily noted,
Karyological Studies and Chromosome Numbers in 43 Hyparrhenia aucta and H. hirta.
also the “V-shaped pair with unequal arms; and finally the presence of only 3 short rod-shaped pairs—these are the leading distinctive features.
The “‘S’’-shaped pair is such a characteristic feature that it deserves some additional remarks. Many dozens of metaphases of the strain with 2n = 30 from 3 localities were investigated but the “S’-shaped pair was found only once (see Text-fig. 1; 3). In this metaphase it was not very distinctly expressed. The number of chromosomes was the same, 30, so the only explanation of its appearance was to suppose that it had developed from some pair of “L’’-shaped chromosomes. As this occurred only in one single metaphase it could not be decided which pair of “L’’- shaped chromosomes has this tendency of transformation into ‘‘S’’- shaped chromosomes. Probably the “‘S” shape of this chromosome has a mechanical condition such that it lies in the metaphase plate more frequently with one of the short arms perpendicular to the plane of drawing. This would mean that it could be taken for a “L’’-shaped or even for a rod-shaped chromosome. The single occurrence in the slides of the 2n = 30 strain would probably represent a 1 per cent frequency or perhaps even less.
With this reservation the absence of “S’’-shaped chromosomes in 2n = 30 strain can still serve as a useful differential character, but it must be compared with the other two mentioned above, especially when only 3 short rod-shaped pairs are present.
It is rather difficult to define distinct morphological differences between the strains 2n = 30 and 2n = 44. The most distinct ones are perhaps: (1) a bluish colour of the leaves (as opposed to green in the strain 2n = 44), (2) white nerves on the leaves (as opposed to green nerves in the 2n = 44).
On the other hand it must be remembered that the chromosomic races and strains do not necessarily differ in morphological characters. The observation on Bromus inermis recently published by Hill and Meyers (5) in which there are many chromosomic but only two morphological strains is an illustration of such behaviour. An even more striking example is provided by Poa pratensis with numerous strains ranging from 2n = 28 to 2n = + 124. Amongst all these strains conspicuous morphological distinctions do not exist. They differ rather in physiological properties (Kramer, 17). A final illustration is provided by Meyers and Hill (23) whose estimation of the number of ‘intraspecific’? chromosomic races in the Gramineae is as high as 99 (from this estimate Poa pratensis was excluded). :
DISCUSSION. Hyparrhenia aucta was included in cytological investigations of Hyparrhenia hirta mainly for the reason that this species commonly
te The Journal of South African Botany.
grows nearby or mixed with H. hirta. (For the same reason a count of the chromosomes of Schizachyrium semiberbe (Text-fig. 1: 5) is included as well. In this species 2n = 50 was found in adventitious root tips.) There is, however, no close karyological similarity between these two Hyparrhenia species.
Firstly, the chromosome numbers differ widely; secondly, the diploid chromosomes of H. aucta are longer and a little wider than those of Hi. hirta. (Compare Text-fig. 1; 1 with 1; 2. 3). (Note: The magnification of fig. 1 is + 1,400x and fig. 2 and 3 + 2.800x.)
If one ignored these essential differences for a moment, one would find some similarities between the H. hirta strain 2n = 44 and H. aucta in the following pairs of chromosomes:
(1) The “S” chromosome pair N9 of H. hirta is similar to H. aucta N7;
(2) the biggest “L” of H. hirta (N10) is comparable with H. aucta N6, with one important reservation, viz. that the distribution of 2 constrictions is not completely identical:
(3) the single short rod pair with median constriction in H. aucta is similar to the corresponding pair of H. hirta, probably to N18. Moreover, there are some similarities between two pairs of “L”’- shaped chromosomes with median constriction to pairs cor- responding in height (N16 and 14) of H. hirta. Regarding this comparison with critical reserve it would appear that only the similarities between “‘S”’- and the short rod-shaped chromosomes would stand, though they differ very much in size.
A distinct similarity in only two pairs is certainly not enough to establish affinity in morphology in complements of chromosomes.
Gluckmann confirmed the writer’s finding of a haploid number of ten in H. aucta but did not observe any irregularity in meiosis of P.M.C. (unfortunately her drawings were not preserved).
These facts probably are sufficient to establish that H. aucta is a piploid species with the basic number ten. This would be in accord with the general estimation of basic chromosome numbers in Gramineae and especially in the tribe Andropogoneae. Avdulov (2, p. 82—83) expressed as his opinion that the basic numbers in Andropogoneae are 9 and 10. In his diagram of the frequency of basic numbers in the mono- cotyledons the basic number 10 has the highest frequency: it occupies the second place (Avdulov. p. 328) after the basic number of 12. In Darlington and Janaki-Ammal’s Chromosome Atlas (6) this numbe> is given for many Andropogoneae. The acceptance of 10 as a basic number for H. aucta will involve some inconvenience in regard to H. hirta chromo- somic valency.
Karyological Studies and Chromosome Numbers in 4 Hyparrhenia aucta and H. hirta.
1
The existence of 2 forms in H. hirta in the Transvaal and on the Rand was known long ago to Prof. Phillips and his co-workers. It was difficult to define the morphological differences between the two strains as there are overlapping forms. For this reason both forms have been fixed from the inception of this work but unfortunately the fixed material of the 2n = 30 strain, which was collected at the Frankenwald Experiment Station and which was provisionally described as “‘tall blue from Frankenwald”’’, has been spoilt by accident in two consecutive years in an overheated thermostat. For this reason the first count concerned the strain 2n = 44.
On account of this occurrence Garber’s (11) publication achieved priority. The above author mainly described chromosome numbers of different species of Sorghum and only incidentally included H. hirta as a member of the same tribe of Andropogoneae by way of illustration. He investigated meiosis only and found the haploid number to be 15. His publication reached South Africa in 1947 and soon afterwards the count of 2n = 30 in root tip metaphases of the “tall blue” strain was confirmed.
The American author was asked to send seed of his strain and to give any information about its origin. In due course information from Mr. B. P. Robinson was received, who kindly supplied a sample of seeds. From this correspondence it appeared that the strain of H. hirta was introduced to the U.S.A. from two institutions in the Union of South Africa in 1941, namely: (1) from the McGregor Museum, Kimberley; (2) from Frankenwald University Experimental Station. Mr. Robinson wrote that it was impossible to state from which of the two places the strain, which Garber and he himself investigated cytologically, originated. There was no evidence in the U.S.A. of differences registered between them. Thus far it has not been possible to obtain seed or further informa- tion about this strain from the McGregor Museum, Kimberley. Neverthe- less, it has been thought reasonable to assume that the Kimberley strain also has a number 2n = 30. If this is not true, there should be some evidence in American institutes of registered differences, or of the failure of germination of the seeds.
Soon afterwards good root tip material of both strains was obtained from the U.S.A. and from the “‘tall blue” form from Frankenwald. It appeared that both strains are karyologically identical, as the diploid number in both was the same (2n = 30). Morphologically both strains also were identical.
In a quick investigation of meiosis of the “tall blue” form no irregularities were found.
46 The Journal of South African Botany.
Another strain of H. hirta, investigated from two localities (1. Wit- watersrand University: 2. Frankenwald Experiment Station) was, however, karyologically quite different. The root tip metaphases were very crowded: the chromosomes overlapped frequently and counting was extremely difficult. The diploid number consistently was 44 from all investigated localities (see the list of strains given later). There were few rare instances in which the number found was 44 + 1 fragment.
This indistinct fragment was small, without any constriction. No relationship could be found between it and the other chromosomes. Moreover, during the investigations of meiotic metaphases and diakinesis in the anther (see former chapter) no body corresponding to the above fragment was found in spite of the great instability in the number of bivalents.
As to the nature and importance of the fragments we first may briefly consider the general position of this question in the world cytological literature where it has been discussed for about 30 years.
Broadly speaking, there are three types of supernumerary chromosomes and fragments: (1) The supernumerary B-chromosomes, described by Ostergren (33) and Lima de Faria (20), both in Anthoxanthum; (2) “Standard” fragments described in Rye by Miintzing (26). These are fragments of the size of the smallest normal chromosomes, in any case they are no bigger: (3) “iso-fragments” (Miintzing, 26), much smaller than the smallest of the normal chromosomes and usually smaller than the “standard fragments’.
The B-chromosomes are usually heterochromatic and when present in some plants they appear during mitosis in every organ.
The “standard fragments” in rye are smaller than the smallest of normal chromosomes. They have distinct subterminal kinetochores. They are separated in meiosis and later exhibit non-disjunction, which means both daughter fragments go to one cell.
The “‘iso-fragments” are the smallest but they still have a distinct kinetochore and are easily recognised in rye by a delay in the separation of the chromatids, which have four free ends during mitotic metaphase. The iso-fragments have little genetical effect in rye when they are single or double, but in plants in which they accumulate in larger numbers they produce quite distinct negative effects (Miintzing, 25, Popoff, 34). In particular they are able to cause a decrease in fertility, as shown both in a reduced ability of seeds to germinate and in a smaller output of seeds. Miintzing (1.c.) has shown their deleterious effect on pollen grain germina- tion. In view of the above remarks in connection with the rare fragments in H. hirta strain 2n = 44 it is clear that the Hyparrhenia fragments do not fit the above types.
Karyological Studies and Chromosome Numbers in 47 Hyparrhenia aucta and H. hirta.
Firstly, they are never heterochromatic; secondly, they are deprived of a kinetochore; thirdly, they are not constant, and fourthly, their participation in mitosis has not been proved:
As to the origin of the supernumerary chromosomes and fragments there are two prevailing views. The first attempts to explain their appearance by duplication of one of the normal chromosomes or one of its arms, for example, Zea mays (Miintzing, 25).
The second view is based on the fragmentation of the normal chromo- somes as an origin of fragments. This view has its extreme expression perhaps in Chakravartis’ paper (5), where this author explains the origin of many new species, especially those with aneuploid numbers, in the families Cucurbitaceae, Musaceae, Zingiberaceae, Cannaceae, Scitamineae, by transverse fragmentation of normal chromosomes in place of secondary constriction. It is quite possible that the rare fragments in H. hirta have a similar origin. This can, however, be expressed only as pure conjecture as there is no evidence either of shortening of normal chromosomes or of direct observation of fragmentation.
The nature of H. hirta fragments and their origin are quite obscure, but it is not thought that they play any important part in the heredity of Hyparrhenia.
From the above it seems extremely improbable that H. hirta and H. aucta should have the same basic number, namely ten, and still more improbable is Garber’s proposition of a basic number of five.
Thus far no distinct affinity between chromosomes of H. aucta and H. hirta has been found, which may be due to the fact that the plants have different basic numbers. We can reasonably assume a basic number of 10 for H. aucta and of 15 for both H. hirta strains. The basic number 15 is one of least frequent numbers in Monocotyledons (see Avdulov, p. 398, and his discussion of frequency of chromosome numbers). It has a fourth place in rarity, after ““4’’ as the rarest number, and 17, 18. On the other hand, its frequency is about the same as the basic number 5 proposed by Garber (l.c.).. We have already examples in Gramineae of a basic chromosome number of 15 in the tribes Paniceae (Pennisetum 2n = 45), Oryzeae (Darlington and Janaki-Ammal, p. 325) and in Stipeae (L.c. p. 350—351). There are further not less than 7 species with 2n = 44. For the latter the author proposes a basic number of 11. This, however, is not acceptable for H. hirta for the following reasons: Firstly, it would not explain the diploid number 30 in the strain “‘tall, blue” from Franken-
wald of the same species; secondly, it would mean that the 2n = 44 strain of H. hirta is tetraploid. The low fertility in the above strain and the frequent variation in numbers of bivalents in meiosis do not support this
48 The Journal of South African Botany.
presumption. Apparently, there is no agreement on the question of the most frequent basic chromosome number in Gramineae. Wanscher (44) considers the most frequent basic number in this family to be n = 7, which is present in 89 species. Next in order of frequency comes n = 14 with 76 species, n = 10 in 10 species and n = 5 is present only in | species.
The tribe Andropogoneae according to Nielson (30, p. 370—3871) definitely has a prevailing basic number n = 10 with few exceptions, but n — 59 is not even considered at all by this author.
In the writer’s opinion the only reasonable choice is to assume 15 as a basic number, at least temporarily until such time as present in- adequate knowledge of the chromosomes of the genus Hyparrhenia has been enriched by further investigations. On the basis of this assumption we can come to two further conclusions, viz.: (1) In the genus Hyparrhenia there are probably two lines of development; one with a basic number of 10 and the other with a basic number 15: (2) in H. hirta there are two strains; one diploid, with high fertility and 2n = 30 and one triploid monosomic, much less fertile, with 2n — 44.
The weights of mature seeds give some support to the above assumption. It has been generally stated that the seeds of polyploids are heavier than the seeds of diploids. Thus it was noted on the 16th of June, 1944, that the average weight of 100 seeds of the 2n = 30 strain was 60 mgm. and of 100 seeds of the 2n = 44 strain 75 mgm. The mature seeds for this test had been collected 2 months earlier and selected by hand using a magnifier. The increase in weight represents a difference of 20 per cent. In spite of great variations in weight over the seasons a one- year estimation could serve as a useful illustration of the polyploid nature of the 2n = 44 strain.
The figures for germinability of the seed also fit in well with the above assumption. In germination experiments with the H. hirta strain 2n = 44 rather low percentages were obtained. The highest for many years was 54 per cent, though the usual rate lay between 30 per cent to 40 per cent and very often was less than 30 per cent. The germination capacity of the H. hirta strain 2n = 30 in the U.S.A. is much higher. As stated by Robinson and Potts (37) it is as high as 85 per cent and the average is 75 per cent. Germination tests of the pure seeds of 2n = 30 strain from Frankenwald never gave results as high as the foregoing. Following on some observations on the time of opening of florets and shedding of pollen grains the following tentative explanation of this behaviour is put forward: Both strains of H. hirta are growing at Frankenwald in close proximity. The flowers open and shed pollen about the same time and thus the chances of inter-strain pollination equal those of intra-strain pollination.
These two kinds of pollen grains are completely different in their chromosomic content and fertilisation value. Practically all pollen grains
NATIONAL E L NSTITNUTE PRIVA r = AO PRETC 04 EPUBLIC OF SOUTH AFRICA Karyological Studies and Gireniesome Wayilbore Ho 49
Hyparrhenia aucta and H. hirta.
of the strain 2n = 30 have 15 chromosomes and are highly compatible in fertilisation, while of the pollen grains coming from the 2n = 44 strain none has a compatible number of chromosomes. Nearly half of them have n = 22, and then follow the numbers 24, 18, 16 and 14. All these are even numbers with few exceptions. To be compatible for the female gamete in the plant with 2n = 30, the foreign pollen grain should at least have an odd number.
Rich co-pollination with the pollen grains shed by 2n = 44 plants with the 15 chromosome type is probably the main cause of the lower fertility of this strain under local conditions as compared with high per- certage germination of the same strain in the U.S.A.
The strain of H. hirta 2n = 30 introduced from South Africa to the U.S.A. found itself there artificially isolated from “‘contamination” by related pollen, as there are no indigenous Hyparrhenia species in the U.S.A. Both strains introduced were apparently of the same chromosomic value (2n = 30) and were therefore pollinated only with pure pollen grains containing n = 15 chromosomes. This then is the chief cause of a much higher percentage of germination and higher fertility.
In connection with the above assumption it would be of interest to know something more definite about the geographical distribution of both strains in the Union of South Africa. Unfortunately, the writer can make only a very modest contribution to this question.
Strains from the following localities were the only ones investigated :—
1. From the Experimental Station, Rietvlei, near Irene,
Transvaal &,4 ae ae Be emo ot 2. Grootfontein Reperanen Station, Middelburg, Cape... 2n = 30 3. Experiment Station, Dohne .. ss <3 .. mn=44 4. From Jaegerbush, Losberg se ae .. g2n=44 5. From Jaegerbush, Losberg, 1 plant one on ee Tie — eo) 6. From the Frankenwald Experiment Station .. eerie 130) 7. From the Frankenwald Experiment Station .. 2n = 44 8. Witwatersrand University, Milner Park, J ohenmesbure 2n = 44
In addition to the above list of localities there is reasonable evidence to suppose that the Kimberley strain sent in 1941 to the U.S.A had probably 2n = 30 chromosomes. (See above for the reasons for this supposition. )
The above findings are certainly not sufficient for making any assumptions about the geographical distribution. It is not even known which strains are predominant in the various localities, but it could be supposed that the samples were sent to the author on the ground that one type of Hyparrhenia appeared to differ from the common type or because it was dominant in the region.
50 The Journal of South African Botany.
In view of this scarcity of information the author feels it would be wise to limit his statements only to the conditions prevailing in the Trans- yvaal, especially around Johannesburg, where both strains grow practically in the same habitats. The 2n = 44 strain of H. hirta is much more frequent, while the H. hirta 2n = 30 strain prevails rather on old vleis.
In addition to the above some details of the technique of counting should perhaps be added. From each locality not less than 10 roots usually belonging to 10 different plants were investigated. In this way each statement on chromosome numbers from different localities is based on not less than 10 slides, with numerous metaphases. The roots of H. hirta 2n = 44 from the University and Frankenwald and the strain 2n = 30, the “‘tall blue’, from Frankenwald and that from the U.S.A. were exceptions to this rule. as with different methods of squashing, staining and fixation more than 100 roots of the strain 2n = 44 and 30 to 40 roots of the 2n = 30 strain were studied.
In spite of these numbers the amazing uniformity, with one single exception, was striking. Only in the plants from Jaegerbush, Losberg, a metaphase with 2n = 56 was found on one occasion. This root belonged to the plant with 2n = 44 chromosomes. Unfortunately, from one crowded metaphase nothing could be learnt about the morphology of the chromo- somes. That was probably a case of a mutant root.
Mention has already been made of the crowdedness of metaphases in the H. hirta strain 2n = 44 and the difficulty of counting them. In order to spread the chromosomes better and make the counting easier experiments were undertaken with pre-treatment of the roots with cold treatment before fixation (see Darlington and La Cour (7), Delaunay, 9). There was also another reason for trying this method. In the course of previous years there was some evidence in cytological literature that cold pre-treatment would reveal a third kind of constriction in chromo- somes (Resende and Cabral, 35). which would be constant for given species and given chromosomes. One of the investigators—F. Resende—even proposed to give them the special term “Olistherozones”’ (Nature, v. 144, p- 481 and Acta Portugaliae Biologica, Vol. 1, fase. 2, 1945).
For these two reasons methodical pre-treatment at a temperature of 4°C. was given to root tips before fixation. The roots were fixed at intervals of one hour starting with a treatment of one hour and increasing up to 24 hours. The shortening and spreading of metaphasic chromosomes was at a maximum after 4—6 hours pre-treatment. However, the added advantage of better spreading and shortening of chromosomes was con- spicuously reduced in value by the peculiarity that they were now dis- tributed in many planes, sometimes very distant ones. The danger of omission in the counting of some chromosomes occurring in different
Karyological Studies and Chromosome Numbers in 51 Hyparrhenia aucta and H. hirta.
planes is obvious. With longer pre-treatment the chromosomes became crowded, and with still longer treatment sticking occurred, while after 24 hours the metaphases were shrunk, exhibiting indistinct clumps of chromatin with frequent bridges in anaphases.
With regard to the new tertiary constrictions, the so-called ‘‘Olis- therozones’’, the results of our experiments were completely negative. This is in line with previous experiments on Senecio isatideus (Krupko and Goldsmith, 13). In this instance constrictions which were visible without pre-treatment disappeared completely. This was not the case, however, with H. hirta. The kinetochores and secondary constrictions are clearly seen when maximum spreading has been achieved, i.e., after 4—6 hours of treatment, but new constrictions were not revealed.
The temperature of 4°C. was chosen for these experiments because Delaunay claimed that he obtained the best results at that temperature with the majority of plants. It is quite possible that H. hirta would respond differently at different temperatures.
For the same purpose soaking in cold water before fixation was also tried. This gave some improvement in the spreading of chromosomes after 2—3 hours of treatment (see also Goldsmith and Krupko, 13) which was just the reverse of Gluckmann’s results with Themeda (unpublished).
Considering the H. hirta strain 2n = 44 as a monosomic triploid plant we could expect that the majority of chromosomes, in somatic metaphases at least, would be found not in homologous pairs but in homologous triplets. In order to check this aspect of the karyogram an attempt was made many times to arrange the drawings of morpho- logically similar chromosomes, cut out of the paper in triplets, but this invariably failed. Only 6 rod-shaped pairs could sometimes be arranged in triplets, but this was without significance because of the smallness of the rod shaped chromosomes. Also there was great uncertainty in deter- mining the nature of the constrictions in these chromosomes. It has been pointed out that it was often difficult to decide which type of con- striction was present, namely, subterminal or median. It is usually easy to arrange all other chromosomes in pairs.
It is supposed that this aspect of the karyogram has some theoretical significance with regard to the character of triploidy. It probably means that triploidy in this strain was achieved very long ago. The H. hirta strain 2n = 44 is an old triploid species in which triplets have had enough time to adapt themselves to the diploid physiological function, and become pairs. It is possible that in early age this strain was a simple triploid with a full complement of 45 chromosomes. For some reason unknown at present one chromosome of the complement was gradually excluded
52 The Journal of South African Botany.
in disjunction, and the strain finally became a monosomic triploid. If this is so the fragment mentioned previously which occurs sometimes in root metaphases may be the relic of the odd chromosome.
ADDITIONAL OBSERVATIONS.
During this work on Hyparrhenia hirta some additional observations were made not directly connected with the cytology of the plant, but probably being of some interest in the expansion of our knowledge of South African grasses.
First may be mentioned observations on the dichogamy of Hyparrhenia florets, which were carried out on the H. hirta strain from the Grootfontein College of Agriculture which has 2n = 30 as described above. The spike- lets and florets were marked with coloured wool threads. In this way the observation was soon made that there is no protandric behaviour at all, contrary to the prevailing statements of German ecologists in many text- books of Ecology. Nearly all of them state that protandry is the prevailing condition in the Gramineae family (in Europe). Apparently it is not the case in H. hirta, at least in the strain from Grootfontein. In this strain protogyny is the prevailing condition. The stigmas appeared early in the morning, sometimes between 8—10 hours. They first had a white colour which was maintained during the first day, but the next day changed to a light yellow. On the second morning the stigmas were coloured a deep red and this colour was maintained, gradually changing to violet-red and ultimately to black-red. Quite possibly this change of colour is connected with pollination or even with the fertilisation process.
Similar observations of protogyny were made by Artschwaeger and Maguire (1) in Sorghum vulgare, though they did not mention the colour of the stigmas in the plants. A remarkable fact is that the florets remain open for the very short time of 30—60 minutes. In addition to the protogynic behaviour, cases of simultaneous appearance of stigmas and anthers were noted in H. hirta.
The second observation is connected with the number of xylem strands in the primary roots. In H. /irta the vascular bundles are all pentarch, without any exception. It may be of value to compare the statements on the same subject in current anatomical literature. Mostly this item is ignored, or there are only observations on cereals, from which a general idea of the structures of other grasses are drawn. For example, Avery (3) mentioned that the primary roots of Triticum are hepta-octarch and according to this author maize roots have even more “‘Tays”’.
The third observation concerns the structure of growing points of adventitious roots. In H. hirta all four histogens are present (see Pl. XIV, fig. 15, Pl. XV, fig. 21). It exhibits a classical picture of the Monocot
Karyological Studies and Chromosome Numbers in 53 Hyparrhenia aucta and H. harta.
structure: the calyptrogen gives rise to the calyptra, the dermatogen to the epidermis, the periblem to the cortex, and the plerome to the central cylinder. As said before, there is a tendency amongst grass growers to see the structure of cereals as a model for all grass structures. In this case such a generalisation would be completely wrong. According to Percival Nelson (29), Hector (14) and Standford (40) the cereals have only three histogens, cortex and epidermis having one common histogen for both tissues. In this respect again H. hirta differs from the cereals.
Avdulov (2, pp. 324—325) attached special attention to the shape and to the position of the first leaf in the grasses. In his opinion Hackel’s (1889) statement that a lanceolate or elliptic first leaf in the Andropogoneae with a more or less horizontal position is a primitive character as com- pared with linear or awl-shaped leaves, as prevailing amongst other grasses, should be extended to the other tribes. He found (l.c., p. 325) the same shape and character of the first leaf in all 6 tribes of Series A in the Gramineae (according to Hackel’s system), which he calls the subfamily Sacchariferae. Moreover, when this shape occurs in other species of Series B of the family it is invariably connected with primitiveness of characters or with the relic nature of that species. In the light of the above, Avdulov’s interpretation is useful perhaps in giving a picture (PI. XV, fig. 24) of the first leaf of H. hirta. It is distinctly elliptical and it keeps a practically horizontal position, at least in the beginning. Its margin is ciliated. Unfortunately, the photograph included fails completely to reproduce ciliation of the margin, which however can easily be seen with a xX 10 magnifier. In this respect the first leaf of H. hirta agrees with Hackel’s rule for the tribe Andropogoneae and with Avdulov’s extension of that rule to the subfamily Sacchariferae.
The fifth observation is connected with the great difficulty experienced in squashing fresh root tip sections of H. hirta for quick staining and counting of chromosomes. Schlerenchymic tissues in root tips were sought in vain but very soon it was apparent that resistance to the squashing force is due to the thick external wall of the epidermis (see Pl. XV, fig. 22). The thickness of this wall is frequently equal to the diameter of the lumen of the epidermis cells and sometimes it is twice as thick as the diameter. This external wall stains distinctly with 1 per cent Congo Red, revealing its cellulosic nature. The same wall may he stained pink with ruthenium red, the colour appearing evenly on the whole thickness of the wall without striations or layers appearing. The impression was gained that the external layer of the wall is a solid cellulosic membrane. Below this wall there is probably a dense elastic layer of cellulosic and pectic slime, highly resistant to pressure. This extremely thick wall covers only the meri-
54 The Journal of South African Botany.
stematic region and the more differentiated parts of the root have an epidermis with a wall of solid cellulose of usual thickness.
RECOMMENDATIONS.
Having in mind the ecological importance of the genus Hyparrhenia in Africa and the possibility of the use on a wide scale of some of its species in soil conservation measures, the author regards it as very important that the following lines of investigation will be carried out:
(1) Counting of chromosome numbers and analysis of meiosis of all species of Hyparrhenia in Africa; (2) chromosome counting and chromosome morphology of H. hirta strains from different countries (up to the Red Sea); (3) collection of facts on the geographical dis- tribution of chromosomie strains of H. hirta in the Union of South Africa, based on direct counting of chromosomes in plants from different localities, but not based on the external morphological characters; (4) experimental plots of the diploid strain of H. hirta should be arranged in different parts of the country with strict isolation of the plots from pollination by other strains of H. hirta or by other Hyparrhenia species.
It is the writer’s hope that these plots would prove the greater fertility of the diploid strain in isolated conditions.
SUMMARY.
There are probably at least two lines of development in the genus Hyparrhenia: one with a basic chromosome number = 10, and the other with a basic number = 15.
Hyparrhenia aucta has the following chromosome numbers: 2n = 20; n = 10. Its basic number is probably 10.
Hyparrhenia hirta has two strains, diploid with 2n = 30, n = 15, monosomic triploid with 2n = 44. The latter has various numbers of bivalents in pollen grain mother cell meiosis: 22, 20, 18, 16, 14.
Laggers are frequent and persisting up to the 1-nucleated stage of the young pollen grain.
The basic number of chromosomes in H. hirta is probably 15.
Of the mature pollen grains of the above-mentioned strain + 20 per cent is degenerated. Normal looking pollen grains germinate very rarely and with difficulty. The tubes are short, growing slowly and are short lived.
There are some mature pollen grains with supernumerary nuclei.
The above disturbances is pollen grain development and the unbalanced number of chromosomes in male gametes are probably the chief causes of low fertility of the monosomic triploid strain.
Schizochyrium semiberbe has 2n = 50.
Karyological Studies and Chromosome Numbers in 55 Hyparrhenia aucta and H. hirta.
ACKNOWLEDGMENTS.
From the time of my first appearance at the Witwatersrand University I was received with great hospitality. Many marks of cordial sympathy and of friendly help have been shown to me by my scientific colleagues, both in the botany department and in other specialities. It is my pleasant duty to thank them all here, both those whom I still see and remember and those who are now working at other places and whom I perhaps have forgotten.
I am deeply indebted to Professor J. V. F. Phillips, former head of the Botany Department, University of the Witwatersrand, for suggesting this investigation on grass cytology. During the war years there were many difficulties and technical shortages which threatened to handicap con- siderably this kind of work, but Professor Phillips’ energy and constant support overcame all obstacles. His enthusiastic approach to the prob- lems of soil conservation and grass investigations in this country was a constant source of inspiration.
I am greatly indebted also to the Department of Agriculture for research grants, which were received through the Frankenwald Botanical Research Station.
My special thanks are further due to the following persons: Professor N. P. Badenhuizen, the present Head of the Department of Botany, for his support in my research endeavours and his interest in them; Mrs. M. Moss, retired Senior Lecturer of the Botany Department, for cordial help in my first days in this University and for constant encourage- ment in my teaching work at this Department; Dr. D. B. D. Meredith for his keen interest in my work on grasses and for his help in arrangement of experiments at Frankenwald and collection of material, for supplying me with current literature and lastly and perhaps most important, for helping to correct the present paper; Dr. H. B. Gilliland, Senior Lecturer of the Botany Department, for naming of many grasses and for useful advice; Dr. E. R. Roux, Senior Lecturer of the Botany Department, for much useful advice; Dr. R. L. Davidson, Lecturer of the Botany Depart- ment and Deputy-Director of Frankenwald Experimental Station, for help in the arrangement of my experiments, for collection of material and for assistance in preparing photographs; Mrs. Crook (formerly Miss Chippindall) for the naming of many grasses.
Many thanks for preparing microphotographs are due to Mr. Armando Salbany from Mozambique, to Dr. Poultney, formerly at Frankenwald and to Mr. G. Stiven.
I thank also Dr. R. E. Altona of African Explosives and Chemical Industries, Limited, for the care of my experiments at Frankenwald.
The Journal of South African Botany.
The generous contribution made by the University of the
Witwatersrand to the cost of printing this paper is gratefully acknowledged.
Finally, I thank all these Experimental Stations, Government
Institutions, Agricultural Officers, here in the Union and in other countries in Africa, who kindly sent me seeds and samples of grasses.
Botany Department,
University of the Witwatersrand, Johannesburg.
BIBLIOGRAPHY.
ARTSCHWAEGER, E. anp R. C. Macurre. 1949. Cytology of reproduction in Sorghum vulgare. (Jour. of Agricultural Research, vol. 57, No. 12, pp. 659—673).
AvputLov, N. P. 1931. Karyo-taxonomical investigations in Gramineae. (In Russian). Leningrad. (Suppl. 34th to the Bull. of Applied Botany, Genetics and Plant Breeding).
Avery, G. 8. 1930. Comparative anatomy and morphology of embryos and seedlings of maize, oats and wheat. (Bot. Gaz. vol. LXX XIX, No. 1).
Brink, R. A. 1925. The influence of hydrogen ion concentration on the pollen tube of the sweet pea, Lathyrus odoratus. (Amer. J. of Botany, vol. XXX, p. 149).
CHAKRAVORTI, A. K. 1948. Theory of fragmentation of chromosomes and evolution of species. (Science and Culture, vol. 13, No. 8).
DaRLiIncton, C. D. anp JANAKI Ammat, BE. K. 1945. Chromosome Atlas. London. 1945.
Darineton, C. D. anp La Cour, L. 1940. Nucleic starvation of chromosomes in Trillium. (Jour. of Genetics, vol. 40, No. 1—2).
DeLaunay. L. 1926. Zeitschrft. Zellf. Mikr. Anat. v. 4, 338—364.
Denaunay, L. N. 1931. Das verkurzen der chromosomen involge der Abkithlung. (Ber. Inst. Pflanzenzticht Maslovka, 4).
Faperceé, A. C. 1945. Snail stomach cytase, a new reagent for plant cytology. (Stain Technology, vol. 20, No. 1).
GarBER, E. D. 1944. A cytological study of the genus Sorghum: sub-sections Para-Sorghum and Eusorghum. (The Amer. Naturalist, vol. LX XVIII, p- 89).
GeERSTEL, D. U. 1949. Hydrochloric acid as a fixative for root tip chromosomes. (Stain Technology, vol. 24, No. 2, 1949).
GoxtpsmitH, E. P. anp S. KrupKo. 1948. The chromosome number and karyo-type of Senecio isatideus D.C. (Jour. of S.Afr. Bot., July, 1948).
Hector, J. M. 1936. Introduction to the Botany of field crops. Vol. 1. Cereals. (Johannesburg: C.N.A.).
Hi, H. D. anp Myers, W. M. 1948. Chromosome number in Bromus inermis Leys. (Jour. of Am. Soc. of Agr., vol. 40, May).
KATTERMANN, G. 1930. Chromosomenuntersuchungen bei Gramineen. (Planta, vol. 12, h. 1, pp. 19—37).
Kramer, H. H. 1947. Morphology and agronomic variation in Poa pratensis in relation to chromosome numbers. (Jour. Amer. Soc. for Agron., vol. 39, No. 3).
La Cour, L. F. 1949. Nuclear differentiation in the pollen grain. (Heridity, vol. 3, p. 3, 1949).
LesBeperr, G. A. 1940. Failure of cytokinesis during micro-sporogenesis in Zea mays following heat treatment. (Cytologia, vol. 10).
Lima DE Faria, A. 1947. Disturbances in microspore cytology of Anthoxanthun. (Hereditas, vol. XX XIII, p. 539).
Karyological Studies and Chromosome Numbers in 57 Hyparrhenia aucta and H. hirta.
McKery, Hazet K. AnD ALFRED CLARK. 1946. The use of enzymes in the preparation of root tip smears. (Stain Technology, vol. 21, No. 3).
ManeEsHwarl, P. 1939. Recent advances in microtechnique II. The paraffin method in plant cytology. (Cytologia, vol. 10, No. 1—2, pp. 257—281).
Myers, W. M. ano H. D. Hitu. 1947. Distribution and nature of polyploidy in Festuca elatior. (Bull. of Torrey Bot. Club, vol. 74, No. 2).
Mout pez, W. E. 1923. Duplication of generative nuclei by means of physio- logical stimuli and its significance. (Genetica, vol. 5, 225—272. 1928).
MUntzinc, ARNE. 1943. Genetical effects of duplicated fragment chromosomes in rye. (Hereditas, vol. 29).
Munrzine, A. 1946. Cytological studies of extra fragment chromosomes in rye. III. The mechanism of non-disjunction at the pollen mitosis. (Hereditas, vol. XXXII, 97—119. 1946).
Nawasuin, 8. 1915. (Bull. Acad. Imp. Sci. St. Petersburg, v. 9, pp. 1821—1834).
Nawasuin, M. 1925. (Genetics, vol. 10, 583—592.).
Newtson, A. 1946. Principles of agricultural botany. Thos. Nelson & Sons, Ltd., London & Edinburgh.
Nietsen, E. L. 1939. Grass studies III: Additional somatic chromosome complements. (Amer. J. of Bot., vol. 26).
Newcomer, H. EH. 1938. A procedure for growing, staining and making permanent slides of pollen tubes. (Stain Technology, vol. 13, No. 3. July).
O'Mara, I. G. 1948. Acetic acid methods for chromosome studies at pro- phase, metaphase in meristems. (Stain Technology, vol. 23 (4); 201—204. 1948).
OSTERGREN, G. 1947. Heterochromatic B-chromosomes in Anthoxanthun. (Hereditas, vol. XX XIII, p. 261).
Poporr, A. 1939. Untersuchungen uber den formenreichtum und die Schartigkeit des roggens. (Angewandte Botanik, Bd. 21, H.4., pp. 325—356).
RESENDE, F. anp A. Capray. 1944. Sur la structure de chromosomes dans les mitoses des meristemes radiculaires III. L’action de la temperature sur le structure chromosomique. (Acta Portugaliae Biologica, vol. 1, f. 1, 1944).
RESENDE, F. 1945. Heterochromatine. (Acta Portugalae Biol. vol. I, f. 2., 1945).
Rosrtnson, B. P. ano R. C. Ports. 1950. Seed setting and germination in Hyparrhenia hirta (L.) Stapf (South African blue stem) as affected by nitrogen, phosphorus and potassium. (Amer. J. Agron., Feb., 1950).
Sax, K. 1935. The effect of temperature on nuclear differentiation in micro- spore development. (Jour. Arnold Arboretum, vol. 16, 301—310. 1935).
Sax, K. 1937. Chromosome behaviour and nuclear development in Tradescantia. (Genetics, vol. 22: 523—533).
Stanrorp, E. E. 1939. Economic Plants. (New York: London, 1939). Appleton-Century Co.
Taytor, W. R. 1925. Chromosome constructions as distinguishing characteristic in plants. (Amer. J. Bot., vol. 12, p. 238).
Taytor, W. R. 1926. Cytological studies on Gasteria II: A comparison of the chromosomes of Gasteria, Aloe and Haworthia. (Amer. J. Bot., vol. 12).
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OL
The Journal of South African Botany.
PLATE XIV.
Fic. 1 anp Fic. 17.—H. aucta, root tip metaphase—2n = 20. Fix. Levitsky (5:5) with 4% formol. Stained—Iron haematox. Thickness—7 pp. Photo. taken with B. & L. apochr. x 90 oil immers. and Comp. oc. x 10. Yellow filter. Magnification + 1150 x.
Fies. 2 To 7, 6 To 11, 16.—H. hirta, strain 2n = 44. P.g.m.c. Fix.—Carnoy. Stained—Iron haematox. Thickness 8 ». Taken with B. & L. apochromat. < 90 oil immers. and Comp. oc. x 12. Magnification + 1000 x.
Fies. 12 ro 14.—H. hirta. Similar strain. Smears, fixed in Nawashin, stained with Crystal Violet after Newton. Mature p. grain.
Fie. 1.—Metaphase, 2n = 20.
Fie. 2.—P.g.m.c. diakinesis with n = 14. Taken in two levels. For continuation see Fig. No. 3. Seen 5 bivalents and nucleolus. Taken with green filter No. 58 Wratten. Exposure 17”.
Fie. 3.—The same pollen grain m.c. another level. Here is visible continuation of nucleolus and of one bivalent indistinct above it. Beneath the nucleolus two bivalents (not seen in Fig. 2). All together one can see 9 bivalents not seen in Fig. 2.
Fic. 4.—P.g.m.c. Ist meiotic metaphase with 2n = 22. Taken with green filter No. 58 Wratten. Exposure 20”.
Fic. 5.—P.g.m.c. Ist meiosic metaphase withn = 18. Filter the same. Exposure 25”.
Fic. 6.—P.g.m.c. Ist meiotic anaphase with numerous laggers. Green filter. Exposure 15”.
Fic. 7.—P.g.m.c. Ist meiotic middle telophase with 4 laggers. Taken without filter. Exposure 4”.
Fic. 8.—H. hirta, strain 2n = 44. Acetocarmine squash. P.g.m.c. Ist meiotic telophase. Laggers. Taken with green filter No. 58 Wratten. Exposure 23”. Optics and magn. like above.
Fie. 9.—Old tetrads with the laggers. Taken without filter. Exposure 4’.
Fie. 10.—V.y.p.gr. (gones), 1-lagger. Taken without filter. Exposure 10”.
Fic. 11.—The same. Dwarf nucleus—dw. n. nucleus—n. without filter. Exposure 3”.
Fie. 12.—Mature p. gr. with 4 nuclei, taken in 2 levels; for continuation see Fig. 13. Yellow filter. Exposure 22”.
Fic. 13.—Continuation of Fig. 12. Exposure 5”.
Fic. 14.—Mature p.g. with 5 nuclei; two of them indistinct—slide fading. Yellow and green filters. Exposure 35”.
Irie. 15.—H. hirta, strain 2n = 30, from Frankenwald. Fix.—Nawashin. Stained— Haematox. + Fast green. Thickness 8 p. Root tip—longitudinal, showing 4 histogens. Taken with B. & L. obj. « 20 Comp. oc. * 10. Magnification + 250 x.
Fic. 16.—V.y.p.g. (gones). Four laggers. Without filter. Exposure—10’.
Fria. 17.—Like Fig. No. 1. Metaphase in root tips epidermis with numerous ““V’’- shaped chromosomes and “S’’-shaped one.
Fic. 18.—H. hirta, strain 2n = 30. Root tip metaphase. Fixation Nawashin. Staining—Crystal Violet. Thickness 10 ». B. & L. Fl. oil immers. x 98,Comp. oc. < 10. . Taken in two levels. Exposure: upper photo 8”, lower one 16”. Magnification + 1200 »
Fic. 19.—H. hirta, strain 2n = 44. Root tip metaphase. Fix.—Levitsky (5:5) with 10% formol. 1% Chrom. acid—8 days. Staining—iron haematox. Thickness 7 ». Optics as in Fig. 18. Exposure 16”. Magnification + 1200 x.
Fic. 20.—H. hirta, strain 2n = 44, root tip, metaphase. Fix. and staining as in Fig. 18. B. & L. oil immers. x 97. Comp. oc. x 7:5. Final magnification + 3300 x. PLATE XV.
Fie. 21.—H. hirta, strain 2n = 30 from Frankenwald. Root tip longitudinal, showing growing point, 4 histogens. Fix.—Nawashin. Staining—iron haematox +- fast green. Thickness 8 p. Taken with B. & L. obj. x 20. oc. « 20., enlarged
+ 4 times. Total magnification + 1000 x.
Fic. 22.-—H. hirta, adv. roots. Growing point longitudinal sect. showing unusually thick ext. wall of epidermis cells. Stained: Congo red + haematox. Thickness 8 wp. Taken with B. & L. obj. 60, ocul. x 10; exposure 2”. Magnification +- 500. ep. = epidermis cell, w = external wall, ca = calyptra cells.
Fic. 23.—H. hirta, strain 2n = 44. Enlargement of Fig. 19, Pl. XIV + 3300 x, to show more distinctly the shape of chromosomes.
Fra. 24.—H. hirta, strain 2n = 44. Seedlings.
PLATE XIV. Karyology of Hyparrhenia.
PLATE XV. Karyology of Hyparrhenia.
SOUTH AFRICAN SEAWEED VEGETATION AND FUTURE INVESTIGATIONS IN THIS FIELD.
By Wm. Epwyn Isaac. (Botany Department, University of Cape Town.)
Paper read at the First International Seaweed Symposium, Edinburgh, July, 1952.
CONTENTS.
PAGE Introduction Bh Bf “is sa0 Gy) Ocean Currents and Sea Renmpenature condinions si 59
General characteristics of the Seaweed vegetation and Aor of ate South African Coasts .. : ae ie de oc cauctOrl The Marine Algae of the West Gees an ar i a: -. 63 The Marine Algae of the East Coast .. si ‘is bit .. 65 Future jou se op x Sg te i ueeOG Summary - wi = af St aa oo OY) Wein uledvementh me ae hs iis an oe se oY) Literature : a “if Bee 0) Appendix: Raxonornie motes with Pines merorentees 56 wa Ol
INTRODUCTION.
Seaweed investigation presents a more complex and varied field in South Africa than in Britain. In the first place the coastline of South Africa is much more extensive and many parts are not easily accessible. Secondly, and still more important, the range of physical conditions is greater due to the influence of two ocean currents. Two other considerations may be mentioned: the seaweed flora is less well known and only scant information is available concerning sub-littoral seaweeds, especially east of Cape Agulhas. This last consideration is important in relation to the examina- tion of drift material since there must often be uncertainty in sorting out what has been thrown up locally from deeper waters and what may have been carried by currents for a longer or shorter distance.
OcEAN CURRENTS AND SEA TEMPERATURE CONDITIONS.
The west coast is subjected to the influence of water of sub-antarctic origin which is referred to as the Benguela Current while the east and south coasts are influenced by the Agulhas Current, a warm water current originating about latitude 11°S. off the coast of East Africa, The Agulhas
59
60 The Journal of South African Botany.
PORT MOLLOTH
PORT ST. JOHN'S
EAST LONDON Q-LANGEBAAN LAGOON PORT ALFRED
> PORT ELIZABETH
CAPE POINT a) FALSE BAY
CAPE AGULHAS
Fre. 1. Outline of Union coastline indicating the chief localities mentioned in the text.
Current flows southwards and westwards until it reaches the Agulhas Bank, which is the only extensive part of the continental shelf around the coasts of Southern Africa. The Agulhas Bank deflects most of the warm water eastwards again but at a higher latitude. Branches of the Agulhas Current, however, move westwards (von Bonde, 1939). Coastal sea temperatures increase in an easterly and northerly direction from Cape Agulhas but they fall in a northerly direction along the west coast of the Union. On the west coast, north of the Union, coastal sea temperatures rise again but even at Walvis Bay just within the tropic of Capricorn, sea tempera- tures are lower than on the east coast. Thus, the average annual tempera- ture of the sea at Durban (21-8°C) is 5-7°C higher than that of Walvis Bay (16-1°C) although Durban is 7° latitude further south (Isaac, 1937a). Between Cape Agulhas and Cape Point the coastal waters are not directly affected by the ocean currents and temperatures are much affected by local factors such as depth of water and topography especially in relation to the south-east winds of summer. Temperature conditions in False Bay are abnormally high in relation to its geographical position. If we except False Bay, however, the region from Cape Point to Agulhas is best regarded as an extension of the west coast.
South African Seaweed Vegetation and Future 61 Investigations in this Field.
For convenience, in the remarks which follow, the coast west of Cape Agulhas! has been referred to as the west coast and the coast to the east as the east coast, although it would be more correct to distinguish between the south coast from Agulhas to about Port Elizabeth and the east coast, north of Port Elizabeth. By “cold” or ‘“‘colder’”’ waters is meant the waters off the west coast as defined above but excluding False Bay and ‘‘warm’’ or “warmer” waters refer to the seas east of Cape Agulhas. The terms “warm” or “warmer” waters are also applicable to the waters of the northern part of False Bay. Clearly such terms in reference to sea temperatures are relative; this is especially the case with regard to ‘“‘cold’”’ waters (Isaac, 1951).
It is inevitable that the existence of contrasting east and west coast sea temperature gradients will result in at least two groups of seaweed floras and vegetation. The contrasts and changes do not present a simple picture since there is overlapping in distribution of the flora and vegetation characteristics between one part of the coast and the next. This results from the fact that species differ in the temperature ranges under which they flourish and in their tolerance to temperatures under which they may occur. In this connection it is well to remember that there is no direct relationship between the range of temperature tolerance and the extent of coastal distribution expressed in miles. A species occurring in a region of relatively rapid temperature change may show a wider temperature tolerance than a species distributed over a longer length of coastline where temperature changes are more gradual. The temperature data available indicate that in general a stretch of west coast will show less temperature change than a corresponding stretch of east coast.
GENERAL CHARACTERISTICS OF THE SEAWEED VEGETATION AND FLORA oF SoutH AFRICAN COASTS.
In spite of the contrast which exists between the seaweed flora and vegetation of the east and west coasts, the South African seaweed vege- tation and flora have a few general characteristics.
A first general characteristic is the relatively limited vertical extent of the inter-tidal seaweed vegetation. This is due chiefly to the limited tidal range and to the paucity of algal growth at higher inter-tidal levels which is in turn associated, at least to some extent, with the climatic conditions of the land (Isaac, 1938). Along the coasts of South Africa the tidal range from low water to high water spring tides varies from about 5 to 6 feet (Bauer, 1933; Admiralty charts). Except locally little
1 Cape Agulhas is the most southerly point of the African continent.
62 The Journal of South African Botany.
or no emersed algal vegetation occurs above high water level of neap tides. On the west coast the prominent alga at and some distance below high water neaps is Porphyra capensis. This species is found from Port Nolloth (Bright, 1938) to Port St. Johns but east of Agulhas it becomes very sporadic in distribution, smaller in size, paler in colour and forms less dense and much smaller communities than on the west coast. On the west coast it frequently forms a dense, more or less continuous girdle* persisting throughout the year while at Port St. Johns an hour’s search may yield only a few individuals. The dense and extensive Porphyra communities of the west coast are not replaced by other corre- sponding communities on the east coast which thus presents an impression of even more limited inter-tidal seaweed vegetation. Locally, especially where spray is hurled upwards by rough seas, small pale plants of Porphyra occur above high water of neap tides and even above high water level of spring tides. Again, in damp shaded places a dense growth of various other algae especially Bostrychia occurs at high inter-tidal levels. Such occurrences tend, however, to emphasise the general barrenness above high water neap tides on the west coast, and east of Agulhas the general barrenness above about mid-tide level. In rock pools, especially where fresh water runs into the sea, Ulva and particularly Enteromorpha spp. may be prominent above high water neaps.
A second general characteristic of the inter-tidal algal vegetation of South African coasts is the predominance of Rhodophyceae. As: far back as 1893 Murray had drawn attention to the relative richness of species of Rhodophyceae in the seaweed flora of South Africa. Few of the South African inter-tidal Rhodophyceae are a bright red colour although such are not lacking, e.g. Plocamium corallorhiza. The promi- nent warm water species Hypnea spicifera and the much less common H. viridis are usually bright green while the common west coast Aeodes orbitosa is usually brown. Other species (Gigartina radula, G. stiriata, cold water Porphyra capensis) are usually dark, almost blackish-red. The Rhodophyceae, however. over the greater extent of the coast dominate the vegetation at every inter-tidal level. Unlike the coasts of Western Europe. the Fucales are not a prominent feature of the vege- tation. The outstanding exception in this respect is Bifurcaria brassicae- formis which dominates a lower inter-tidal level from Cape Town to Cape Agulhas (Isaac, 1951). Sargassum longifolium is locally common or even, very locally, dominant, in the upper sub-littoral and lowermost littoral levels between Cape Point and Cape Agulhas (Isaac, 1947) and at Dwesa on the Transkei coast. Other species of Sargassum are common in the
> The term “girdle” as recommended by Feldmann (1951. p. 321) is used here instead of “zone”.
South African Seaweed Vegetation and Future 63 Investigations in this Field.
warmer waters east of Agulhas but these plants do not dominate inter- tidal girdles although locally they may form clans of emersed plants as well as sometimes being common in the upper sub-littoral and in rock pools, the vegetation of which they sometimes dominate. Another member of the Fucales, Carpophyllum scalare is abundant or dominant very locally at Port Alfred and at Dwesa. In warm waters, members of the Caulerpaceae may dominate the vegetation or cover areas to the exclusion of other plants in shallow sea or at low inter-tidal levels. This is the case with Caulerpa filiformis in shallow water, usually in sand, in places at Port Alfred (The Kowie) and to a lesser extent in localities from East London to Port St. Johns, as well as in places on the north-west coast of False Bay (part of the St. James coast); and at lower inter-tidal levels Cawlerpa racemosa var. zeyheri occurs in moderately sheltered places where there is swell, for example at Port Alfred, East London and Port St. Johns. Still, such occurrences as we have cited can be regarded as local intrusions into levels which are chiefly dominated by Rhodophyceae along the entire length of the coastline of the Union of South Africa.
Brief attention may here be called to those ubiquitous genera Ulva and Hnteromorpha. The distribution of these plants is largely related to salinity variations and they flourish under conditions of both low and high salinity. Thus along the coastline of the Union Ulva lactuca and species of Enteromorpha occur in rock pools high in the inter-tidal area as well as in places where there is a mingling of fresh and salt water. Plants of these genera also occur in places where they remain emersed by the falling tide although they rarely show signs of drying out since they occur in habitats where there is spray or where water is retained due to the presence of numerous small depressions of the rock surface. Of the emersed Ulva, U. lactuca is more characteristic of cold waters, U. rigida flourishes characteristically east of Cape Agulhas, and U. minuta is characteristic of warm waters. The emersed micro-species of Hnteromorpha are a feature of the warmer waters.
THe Marine ALGAE OF THE WEST COAST.
The contrast between the seaweed vegetation of the west coast north of Cape Town and of the east coast north of Port Elizabeth is obvious and striking but the contrast is less marked for the region between Cape Agulhas and Port Elizabeth (South Coast) and either the west coast or the east coast north of Port Elizabeth. Clearly the region east of Agulhas needs to be subdivided, but before this can be done satisfactorily more data are needed for the stretch of coast between Agulhas and Port Elizabeth. The west coast can be subdivided into two:—
64 The Journal of South African Botany.
I. Port Nolloth to Cape Town. II. Cape Town to Cape Agulhas but excluding False Bay. Locally, conditions may deviate to a considerable extent from the con- ditions prevailing in neighbouring districts. This is pre-eminently the case with False Bay which needs to be considered on its own. It is also the case with the Saldanha Langebaan lagoon.
The most obvious characteristic of the west coast is the presence of an extensive sub-littoral growth of kelps (Isaac, 1937b, 1938, 1942). These beds extend to depths of at least 25 to 30 feet since the stipes of the largest species, Ecklonia maxima attain these lengths. The fronds and sporophylls of Ecklonia toss about at the surface of the water. Laminaria pallida is a second common species of kelp. Laminaria is a smaller plant than Ecklonia and it lacks a float and hollow stipe which are found in the latter but it may well extend into deeper waters. Precise data on this matter are lacking. A third west coast kelp is a species of Macrocystis which in the past has been named M. pyrifera: the specific identity of this plant, however, is somewhat uncertain.* The kelps are typically sub- littoral plants but in places they occur at the lower inter-tidal levels. Macrocystis is much less abundant than the other two species, being con- fined to a limited stretch of the southern part of the west coast north of Cape Point but locally it may be abundant. It occurs in situations sheltered from the full force of the sea, as in quiet bays or within a palisade of Ecklonia (Isaac, 1937b). Laminaria pallida is more typically a cold water species than Ecklonia maxima. The former kelp is at best a rare species east of the Cape Peninsula* and becomes relatively more abundant in a northward direction along the west coast. Ecklonia occurs from Port Nolloth (Bright, 1938) to Cape Agulhas and it is a prominent plant over the greater part of this range. At its eastern limits it is a relatively small plant and not abundant. In many localities large quantities of kelp are thrown up on the shore and accumulate above tide level.
A second outstanding characteristic of the west coast is the presence of a girdle of Porphyra capensis extending downwards from high water neaps. The growth of Porphyra is often dense, P. capensis forming almost pure communities. On the west coast the plants are large, of a dark purplish red colour and the Porphyra capensis community (association) remains without essential change throughout the year (Isaac, 19375: 1942).
Taken as a whole the common and characteristic cold water species are relatively large; such are Champia lumbricalis and Aeodes orbitosa. Other large plants found in cold water are Gigartina radula, G. stiriata
’ A paper on South African Macrocystis is in course of preparation. + Unless it is common in deeper water so as not to be visible at the surface.
South African Seaweed Vegetation and Future 65 Investigations in this Field.
and Codium fragile. Splachnidium rugosum is a larger plant and more abundant on the west coast than in the warmer waters east of Agulhas. Small species are also found, e.g. Caulacanthus ustulatus, which is widely distributed in cold and warm waters.
The outstanding difference between the west coast north of Cape Town and the part from Cape Town to Cape Agulhas is that the “fucoid’’ species Bifurcaria brassicaeformis is a prominent species of the latter where it dominates a girdle in the lower part of the inter-tidal region. It forms dense communities (associations) to the practical exclusion of other plants (Isaac, 1951). Over the greater part of this sub-region Gelidiwm pristoides also occurs.
THe Marine ALGAE OF THE Mast Coast.
The east coast seaweed vegetation presents a marked contrast to that of the west coast in three outstanding respects:—
(1) The absence of large sub-littoral algae reaching the surface of the water.
(2) The absence of a Porphyra girdle although, as indicated earlier, P. capensis extends at least as far north-eastwards as Port St. Johns.
(3) The seaweeds are in general of smaller size than those of the cold waters and dense mat-like or sward-like mixed communities of small algae are a prominent feature.
As a result of these characteristics the coasts of the warmer seas have a much more barren appearance than those of the colder seas at high water of all tides and at low water of neap tides. At low water of spring tides, however, a great and varied wealth of algal growth is seen.
Although the large kelps are absent east of Cape Agulhas, two species of Ecklonia are found in warmer waters: EL. richardiana and EL. biruncinata. These plants are most typical of the central part of the warm water region and H#. biruncinata is seemingly far more abundant than H. richardiana but further study of the warm water Ecklonias is needed. E. biruncinata is dominant in places at Port Alfred and East London and shows a very luxuriant growth at Dwesa where over most of the coast it dominates the uppermost sub-littoral. As compared with the cold water kelps, the warm water Ecklonias are small plants usually not exceeding 4 feet in length inclusive of stipe and frond. Since these plants are relatively short the warm-water Ecklonia girdle is relatively narrow as seen at the surface of the sea and thus is never such a spectacular sight as may be presented by the kelp association of cold waters.
While there is a smaller bulk of algal tissue between tide levels in warmer as compared with colder waters, the flora is richer in species.
66 The Journal of South African Botany.
The increase in the number of species becomes more marked and tropical elements more pronounced in a north eastward direction from Cape Agulhas, these changes being correlated with a gradient of increasing sea temperatures.
Of the warm water species, Hypnea spicifera is a widespread .dominant plant at the lowest inter-tidal levels. The species is dealt with in a separate paper (Isaac and Hewitt, 1953). Gelidium pristoides and G. reptans are also worthy of note. The former is essentially characteristic of moderately warm waters but is distributed from the central west coast (Kommetje) of the Cape Peninsula to about 60 miles north of Port St.-Johns. G. reptans extends further into warmer waters (Stephenson, 1947). These species are found at mid-tidal levels. At the lowest tidal levels we find Gelidium cartilagineum and the smaller, slenderer but somewhat similar G. rigidum.
From the floristic point of view the warmer seas are characterised by a greater wealth of littoral Chlorophyceae and Phaeophyceae than the colder seas. The characteristic Chlorophyceae belong especially to the Siphonales and Siphonocladiales. Among the former are a number of species of Caulerpa, C. filiformis and varieties of C. racemosa being frequently very abundant. Mention may also be made of Halimeda cuneata, Pseudocodium de-vriesei and several species of Codiwm. Among the Siphonocladiales are those strange algae, Valonia acgagropila and V. macrophysa. Prominent among the Phaeophyceae are Sargassum spp. and. Dictyotales. Sargassum longifolium is exceptional in that it flourishes in places between Cape Point and Cape Agulhas in which localities it grows intermingled with Ecklonia maxima (Isaac, 1947). Of the Dictyotales, Dictyopteris, Zonaria tournefortii and Padina spp. including P. com- mersonit may be listed; all plants found exclusively in warmer waters, The following are some of the Rhodophyceae known only well within the warm water region: Hypnea viridis?, Dictymema stephensonir, Corallopsis aculeata, and Mesotrema elegans,
It should be realised that the species named in the foregoing account by no means exhaust even the common algae of the South African coast as no more has been attempted than a general sketch of the most out- standing features of the algal life of South African coasts.
FutTuRE INVESTIGATIONS.
The early history of the study of South African seaweeds will be published elsewhere and it will be sufficient for our present purpose to
5 Range given by Papenfuss (Papenfuss, 1947) is Natal coast. It was found by the writer growing on the Pondoland coast (Port St. Johns, Mpandi) and on the Transkei coast at Dwesa.
South African Seaweed Vegetation and Future 67 Investigations in this Field.
draw attention to the fact that until the early thirties only a little work had been done in this field. From the early thirties onwards there was an increase in the bulk and scope of the work published. This work has included ecological studies, life history investigations and taxonomic work. Much of the taxonomic work has been concerned with corrections of previous errors in nomenclature without any change in the delimitation of the species concerned but a number of new species have also been described. Kylin, Levring, Mantza and especially Papenfuss have been active in this work.
As a result of the ecological work of Stephenson and his co-workers, who dealt with algae as well as with animal species, and of Isaac, a general picture is available of the geographical distribution of at least most of the chief algal species and of the main features of the seaweed ecology of South African coasts. Further information is needed to complete and clarify this general picture. Thus more studies of particular localities are needed as well as of the algal ecology of the coast between Cape Agulhas and Port Elizabeth. Also, even in terms of a general picture, certain published accounts need amplification and correction, as for example the account given of the algae of Port Elizabeth by Stephenson, Stephenson and Bright (1938). Detailed ecological investigations of particular localities, however, would possibly be more profitably postponed until more taxonomic work has been done. The need of critical taxonomic investiga- tion of certain genera and groups of genera is apparent to investigators of South African seaweed ecology. This applies especially to the algae of warm waters. The conduct of seaweed investigations would be greatly facilitated by the publication of a flora. The time is possibly not ripe for the publication of such a work but the publication of a provisional flora would prove a great boon. Meanwhile there is considerable scope for detailed work on the ecology and physiological ecology of common species and groups of species as well as for preliminary investigations of the floras and ecology of rock pools and of the sub-littoral. The need of further work relating to the general algal ecology of South African shores has been indicated above.
In relation to the autecology of common species, it may be pointed out that little or nothing is known on many matters of importance relating to the exploitation of South African seaweeds for industrial and com- mercial purposes. Information is much needed on the following matters:—
(1) Estimation of the absolute growth density of individual species in sample areas; density to be expressed in terms of fresh and dry weights per unit area.
68 The Journal of South African Botany.
(2) The extent to which perennial species can be cut back and regenerate and studies of the rate of regeneration.
(3) The rate of re-colonisation by algal species following the clearing of sample rock surfaces.
One study bearing on this subject has already been published (Bokenham and Stephenson, 1938).
(4) Seasonal reproductive cycles.
Work on item (4) is especially urgent in view of possible commercial exploitation. The investigation of seasonal reproductive cycles involves collection and sorting of adequate samples of a species at regular intervals throughout the year for a few years. It also involves the examination of samples from a number of localities, especially in the case of those species which show a relatively wide tolerance of changes in habitat conditions. Such work will be chiefly directed, in so far as harvesting is concerned, to determining whether there are months of the year during which the plants should not be collected. Provisional advice for a given species might be given after one or two years’ investigation but more certain information will involve work extending over longer periods. With such species as those of the Laminariales and Fucales the problem is relatively simple since what is involved is periodic determination of the proportion of fertile and non-fertile diploid individuals, since the haploid individuals are microscopic and not collected (Laminariales) or absent (Fucales). With the majority of Rhodophyceae, however, sorting of samples into non- fertile, male, female and tetrasporic plants is involved. As these phases of a single species are usually all morphologically similar a much more complex problem is involved.
(5) Seasonal changes of vegetative parts of perennial species.
This includes for a given species assessment of periods of relative dormancy and of active growth or the establishment of the fact that growth is more or less uniform throughout the year. It also includes a determina- tion of the extent to which an increase in tissue in a particular species is due to the formation of new plants by sexual or asexual reproduction and to what extent it is due to vegetative increase of existing plants. For example, to what extent is the dense growth of the Hypnea spicifera and Bifucaria brassicaeformis associations due to the vegetative growth of new fronds from the creeping rhizomes? The answer to this question will clearly have a bearing on action to be taken in relation to seasonal reproductive cycles.
The information obtained in relation to the exploitation of species of economic importance is necessary if exploitation is to be based on a sound conservation basis. In this connection, however, it is fair to point out that in the case of a few species (e.g., Ecklonia maxima and Gracilaria
South African Seaweed Vegetation and Future 69 Investigations in this Field.
confervoides) exploitation can proceed far by making use of cast up weed. This, however, is not the case with such species as Gelidiwm pristoides, Gigartina radula, Aeodes orbitosa, Hypnea spicifera and Porphyra capensis, to name some of the species of actual or potential economic importance.
The information obtained from such studies will be of ecological importance as well as of economic importance. Autecological information, however, is needed for a wider range of species both perennial and annual. For the warmer waters especially, it is necessary to follow out the times of disappearance of certain species as well as of changes in relative abundance and any changes that there might be in inter-tidal level.
(6) Seasonal changes in the amounts of the chief organic compounds present.
This information will be of value to the biochemist and physiologist as well as to the industrialist.
From these remarks it will be clear that while a general picture of seaweed distribution on South African coasts is now available much work remains to be done. While further detailed work in certain directions is held up until further taxonomic investigations are completed, the autecology of the common species and preliminary ecological work on hitherto neglected aspects present fruitful fields for investigation.
SUMMARY.
The study of South African seaweed vegetation is complex due to the extensive coastline, the range of sea temperatures, and the imperfectly studied algal flora.
Along most of the coast the coastal waters are affected by one of two ocean currents; the cold Benguela Current moving northwards along the west coast and the warm Agulhas Current moving southwards and west- wards along the east and south coasts as far as Cape Agulhas, the most southerly point of Africa. Between Agulhas and Cape Point sea tempera- tures are affected by branches of the Agulhas Current, coastal topo- graphy and prevailing winds. False Bay has abnormally high tempera- tures for its geographical position and its algal flora and vegetation must be considered separately. For convenience in a general account, the coasts west and east of Agulhas are called west and east coast respectively. The seaweed flora and vegetation of east and west coasts show marked contrasts although there is overlap, especially at their southern limits. Changes are also evident along each coastline in relation to sea temperature gradients.
Certain features are common to both coasts. (a) Limited vertical extent of inter-tidal vegetation due to narrow tidal range (low water springs to high water springs, 5—6 ft.) and paucity of algal growth at
70 The Journal of South African Botany.
higher inter-tidal levels. Algae are mostly absent above high water neaps on west coast and above mid-tide level on east coast. (6) Over most of the coast Rhodophyceae dominate every inter-tidal level. Outstanding exceptions are the dominance at a lower inter-tidal level of Bifurcaria brassicaeformis from Cape Town to Cape Agulhas and the local dominance of Caulerpaceae in warm waters.
The west coast is characterised by extensive sub-littoral growths of large kelps—EHcklonia maxima, Laminaria pallida and to a much smaller extent, Macrocystis, and by a girdle, frequently dense, of Porphyra capensis extending downwards from high water neaps. East coast species of EHcklonia are small and much less abundant. A Porphyra girdle is absent although small, pale plants of P. capensis occur as far north on the east coast as Port St. Johns. Hast coast seaweeds are mostly smaller and dense mixed communities of small algae are common. The flora is richer and many species are confined to warmer seas.
Future investigations are considered, bearmg in mind information needed for seaweed exploitation on a conservation basis. While detailed investigation is held up in certain directions until further taxonomic work is completed, preliminary ecological work on previously neglected aspects and the autecology of common species present fruitful fields of investigation.
ACKNOWLEDGEMENT.
Some of the observations included in this paper were made while the author was doing field work financed by the South African Council for Scientific and Industrial Research.
REFERENCES.
Bauer, H. A. (1933): A World Map of Tides, Geogr. Rev. vol. 23, p. 259.
BoxenuamM N. A. H. and StepHEenson, T. A. (1938): The Colonization of Denuded Rock Surfaces in the Intertidal Region of the Cape Peninsula, Ann. Natal Mus., vol. 9, p. 113.
Bricut, K, M. F. (1938): The South African Intertidal Zone and its Relation to Ocean Currents, III. An area on the Northern Part of the West Coast, Trans. Roy. Soc. S. Africa, vol. 26, p. 67.
FELDMANN, J. (1951): Ecology of Marine Algae, Chap. 16, of Manual of Phycology (Edited by G. M. Smith) Waltham, Mass., U.S.A.
Tsaac, Wm. Epwyn (1937a): South African Coastal Waters in relation to Ocean Currents, Geogr. Rev. vol. 27, p. 651. (19376): Studies of South African Seaweed Vegetation. I.—West Coast from Lamberts Bay to the Cape of Good Hope, Trans. Roy. Soc. S. Africa, vol. 25, p. 115. (1938): The Geographical Distribution of Seaweed Vegetation in relation to temperature and other factors, with special reference to South Africa, Comptes rendus du Congrés international de Géographie, Amsterdam, 1938, tome ii, Section 7, p. 12, Leiden. (1942): Seaweeds of Possible Economic Importance in the Union of South Africa, Jour. South African Botany, vol. 8, p. 225. (1949): Studies of South African seaweed vegetation. II.—South Coast: Rooi Els to Gansbaai, with special reference to Gansbaai’, Trans. Roy. Soc. S. Africa, vol. 32, p. 125.
South African Seaweed Vegetation and Future ol Investigations in this Field.
(1951): Observations on the Ecology of Bifurcaria brassicaeformis (Kiitz.) Barton, Jour. Ecology, vol. 39, p. 94.
Isaac, Wm. Epwyn & Hewitt, F., The Geographical Distribution and Ecology of Hypnea spicifera, Paper presented to First Seaweed Symposium, Edin- burgh, 1952. (This Journal, to appear, 1953.)
Murray, G. (1893): A Comparison of the Marine Floras of the warm Atlantic, Indian Ocean, and the Cape of Good Hope, Phycological Memoirs, part 2, p. 65.
Papenruss, G. F. (1947): New Marine Algae from South Africa: I, Univ. Calif. Publ. Botany, vol. 23, No. 1.
STEPHENSON, T. A. (1947): The Constitution of the Intertidal Fauna and Flora of South Africa. Part III, Ann. Natal Mus., vol. XI, p. 207. STEPHENSON, A. and Bricut, K. M. F. (1938): The South African Intertidal Zone and its relation to Ocean Currents, IV, The Port Elizabeth District, Ann. Natal Museum, vol. IX, p. 1.
Taxonomic NOTES. Chlorophyceae. Ulva minuta Papenfuss, ined. Papenfuss’ authenticated material (L. 131) in Botany Department, University of Cape Town.
Phaeophyceae.
Ecklonia biruncinata (Bory) Papenfuss. This plant was known earlier as H. radiata (Turn.) J. Ag. Papenfuss (1940) later published the view that the plant should be named £. exasperata (Turn.) J. Ag.; being regarded as a distinct species and not as a variety of H. radiata. Still later (Papenfuss, 1944), this species was renamed E. biruncinata (Bory) Papenfuss since the plant was first described as Laminaria biruncinata by Bory in 1826.
Ecklonia richardiana J. Ag. Stephenson (1947) regards the South African plants named #. richardiana by Papenfuss (1940a) as probably variants of H. biruncinata but he gives no reasons for his view.
Rhodophyceae.
Aeodes orbitosa (Suhr) Schm. In earlier papers the name Iridaca capensis was used to cover both Aeodes orbitosa and Iridophycus capensis.
Gelidium rigidum (Vahl) Grey. There is some doubt as to whether the plant known by this name in South Africa is not G. amansii (Lamour) Lamour.
Gigartina stiriata (Turn.) Aresch. This includes the tetrasporie plant which is morphologically distinct and was formerly known as G. burmanii (Mert.) J. Ag.
CHANGES IN NOMENCLATURE. Chlorophyceae. Caulerpa filiformis (Suhr.) Hering; C. ligulata Harv. ex J. Ag. (Papenfuss, 1940a).
Phaeophyceae.
Ecklonia maxima (Osbeck) Papenf.; 2. bwecinalis (L.) Hornem. (Papenfuss, 1940b).
Stypopodium zonale (Lamour.) Papenf.; S. lobatwm (Ag) Kutz. (Papenfuss, 1940a).
Rhodophyceae. Martensia elegans Hering: Mesotrema elegans (Her.) Papenf. (Papenfuss, 1942).
REFERENCES.
Parenruss, G. F. (1940a): Notes on South African Marine Algae, I., Bot. Notiser, 1940.
———— (1940b): A revision of the South African marine algae in Herbarium Thunberg, Symbolae Botanicae Upsaliensis, vol. 4, No. 3.
a (1942): Notes on algal Nomenclature: I. Pollexfenia, Jeanerettia and Mesotrema, Proc. Nat. Acad. Sci. Washington, vol. 28, p. 446.
(1944): Notes on Algal Nomenclature, III. Miscellaneous species of Chlorophyceae, Phasophyceae and Rhodophyceae, Farlowia, vol. 1, p. 337.
SrepHEeyson, T. A. (1947): The Constitution of the Intertidal Fauna and Flora of South Africa, Part III, Ann. Natal Mus., vol. XI, p. 207.
y, i, 5 , eis i 7 ‘oe ag TRADE Bey
: et! g i
ISSUED
IO) IL,
JOURNAL OF
SOUTH AFRICAN BOTANY VOL. XIX.
THE MORPHOLOGY, GEOGRAPHICAL DISTRIBU- TION AND ECOLOGY OF HYPNEA SPICIFERA (SUHR.) HARV.
By Wm. Epwyn Isaac and FLrorence Hewirr. (Cape Town and Rhodes Universities.)
(With Plates XVI and XVII.)
(Paper presented to the First International Seaweed Symposium, Edinburgh, July, 1952.)
CONTENTS.
PAGE
Introduction... : es Ss si Ps bos Be 73 Morphology and Colour: of es ee % ie sy 74 Geographical Distribution Les Be * Hs be 5 Ud Intertidal Position - ee ed ne ee oe nes 81 Keological Status ae ay be fee se ss 81 Occurrence in relation to iSiesaaaiiys a ate i oie a 82 - Summary : mG Ls she a bs Be Be 83 Acknow. ledgers be a a 23 ie a Ce 83 Literature eae i = sh a ate as et 84
This report is presented because Hypnea spicifera is one of the most important ecological species at intertidal levels over a large part of the South African coast, and because of its possible economic importance. The published information relating to it is scattered and insufficient to give a clear picture. It is one of several species of Hypnea occurring in the intertidal zone, but it is much more common than any of the others.
The account given here of the morphology and ecology of the species is chiefly based on observations carried out on plants growing from Richmond (Boknes) to the Great Fish River Mouth and is thus to be regarded as a preliminary account of the species in South Africa as a whole.
73
24
1958
74 The Journal of South African Botany.
EAST LONDON
GR FISH RIVER MOUTH
PORT ALFRED
| PORT ELIZABETH CP MOP ZOR SOE 4050) Scale in Miles
Fic. 1. The coast from Port Elizabeth to East London.
Morphology and Colour.
There are distinct male, female and tetrasporic plants which are of similar morphology and size. Detailed studies at Port Alfred (The Kowie) over a period of a year showed that in that locality tetrasporic and sexual plants occurred at all seasons, though the sexual plants were always found to constitute a very small proportion of the population. This conclusion was supported by additional observations over a stretch of coast from Diaz Cross (approximately six miles east of Richmond) to Fish River Mouth (Fig. 1). Similar studies are needed over other parts of its dis- tribution range.
The plant (Fig. 2) consists of a tuft of erect, cylindrical fronds arising from a creeping prostrate system in character somewhat resembling a bird’s nest. This is further dealt with in considering the formation of communities dominated by Hypnea spicifera. The erect fronds are densely crowded together and often much branched, giving the plant a bushy appearance. The main axes and branches of the upright fronds have straight tips and more or less pointed apices. ° Mature fronds are often 30 to 40 cms. (about 12 to 16 inches) long or more, and about 1-5 mm. in diameter near the base. A length of nearly 60 cm. (nearly 2 ft.) has been recorded. Branching is irregular and in all directions. Of the mature
76 The Journal of South African Botany.
Itc. 3. Enlarged view of fertile region of tetrasporic plant of Hypnea spicifera. Stippled areas are fertile parts of stichidia.
fronds the fertile are the more conspicuous, since they are usually several ems. longer than the vegetative fronds and often greater in diameter. The upper portions of the fertile fronds are usually densely covered with numbers of short spinulose branchlets which form a stiff bristle-like covering on the main axes and their branches, extending to within a few millimetres of the tips. These specialised branchlets (stichidia) bear the reproductive organs (Fig. 3). Tetraspores occur in zonate groups within the tissues of the stichidia. The antheridia occur in sori in depres- sions on the surface of the thallus. Cystocarpic fronds are readily identifiable to the naked eye by the presence of globular fruits about 1 mm. in diameter and bright pink when ripe.
The Morphology, Geographical Distribution and Ecology WY of Hypnea spicifera (Suhr.) Harv.
The colour is variable and in the main appears to be related to the level at which the plant grows. Plants in the upper part of the Hypnea girdle have short, succulent upright fronds glossy green in colour, with trans- lucent tips. Plants in the lower portion of the girdle have long dark fronds varying in colour from dark olive green to almost black. In the lowest part where wave action is most severe the long blackish fronds are often wiry and sparsely branched. Mature parts of the prostrate system are dark in colour. The young fronds of both the erect and prostrate systems are a pale, semi-translucent pink colour. Fertile fronds, especially cystocarpic fronds, tend to be a more brownish green than the vegetative fronds of the same plant.
Geographical Distribution.
More data are needed before a full and exact picture can be given of the distribution of Hypnea spicifera on the coasts of South Africa. The general outlines of the picture, however, are clear on the basis of the data available.
Hypnea spicifera is not endemic but the only record of its occurrence outside the Union known to the writers is at Karachi on the north-west coast of India (Bérgesen, 1934). On the coast of the Union it has a very wide distribution (Fig. 4), being one of the most widely distributed sea- weeds on South African coasts. It has been recorded from the northern coast of Natal (Umpangazi) to Buffels River within less than 40 miles south of Port Nolloth (Stephenson, 1947).
A bare statement of the geographical range on the Union coasts of such a widely distributed species as Hypnea spicifera gives an erroneous impression since the size of the plant and its prominence in the seaweed vegetation varies much within its distribution range. As an important constituent of the seaweed vegetation it has two centres of distribution (Fig. 4):
(a) From about Boknes (about 50 miles east of Port Elizabeth) to the northern coast of Natal.
(b) False Bay and the southern end of the west coast of the Cape Peninsula.
The first of these is much more extensive geographically than the second. In fact it is or rather, it includes (as will be shown later) the true centre of distribution. The smaller centre is best regarded as derivative or secondary since locally favourable conditions! make it possible for a
1 For comments and references on ocean currents and sea temperature conditions in South African coastal waters see: Isaac, 1937a and Isaac, 1953a.
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The Morphology, Geographical Distribution and Ecology 79 of Hypnea spicifera (Suhr.) Harv.
GANSBAAI DANGER Po!
sTRUYS BAY CAPE AGULHAS
———————————— ce) 10 20 30 40 Sede m Miles
Fic. 5. The Agulhas Peninsula and the coast to the west as far as the eastern end of False Bay.
widely distributed species to become ecologically important in localities distant from the main centre of distribution.
Except at Rheboksdam Bay (Isaac, 1937b), Hypnea spicifera is not a species of ecological importance on the west coast where it is rare or occasional. From False Bay to and including Port Elizabeth it shows an erratic distribution but additional information is needed relating to its occurrence along this considerable stretch of coast (about 500 miles). In some localities such as Struys Bay and Agulhas (Fig. 5) it is absent or rare; in other localities, while it is not uncommon it is not one of the common, let alone dominant or sub-dominant, species. Thus at Gansbaai it is a constituent of the mixed algal vegetation of which it is not one of the commonest species; further, the mixed algal vegetation is rather poorly represented and is one of four possible types of algal vegetation at low water level of spring tides, the most common community being the Bifurcaria association (Isaac, 1949; 1951).
In other localities such as Frikkie’s Baai on the eastern side of Danger Point, Pearly Beach between Quoin and Danger Points, and Hermanus
80 The Journal of South African Botany.
(Fig. 5) it is a common or locally prominent species. In the Still Bay region Hypnea spicifera is listed as one of the algae occurring on an isolated rocky mass and in an annotated list it is marked with an asterisk to indicate that it is a fairly or very common species (Stephenson, Stephenson and du Toit, 1937). As far as our evidence goes, nowhere between False Bay and Port Elizabeth does Hypnea spicifera attain the status of a dominant species but this view may have to be modified when more information is available. In the Port Elizabeth district (Port Elizabeth to Chelsea Point), the small amount of this species is a note- worthy feature. It is the converse as it were to the dominance of Corallinaceae and Laurencia spp. at the lowest intertidal levels. This point was not made by Stephenson, Stephenson and Bright (1938).
On closer examination of the evidence it becomes clear that Hypnea spicifera is not uniform in its ecological status throughout its two centres of distribution. In the secondary centre, the plant flourishes best along the north-western and northern coasts and the northern half of the eastern coast of False Bay. Over this extent of coastline it is dominant in places at the lowest intertidal levels although the Hypnea girdle may be a narrow one. Along most of the east coast of the Cape Peninsula to the southern end of the west coast (Rheboksdam Bay) the species is more erratic in its ecological importance since it may be rare, occasional and _ local, common or very common to locally dominant.
In general, it clearly becomes ecologically more important in a north- ward direction along the east coast of the Cape Peninsula, attaining optimum development in its secondary centre of distribution along the north-western, northern and eastern shores of False Bay. In regard to its major centre of distribution, Hypnea spicifera flourishes best from about Richmond to somewhere between East London and Port St. Johns. At East London this plant is abundant and except in more sheltered situations it is the outstanding dominant species at lower intertidal levels. At Port St. Johns Hypnea spicifera is still frequently a dominant species at lowest intertidal levels but there is evidence that it has already extended beyond its region of optimum development. This is seen in its smaller size which does not usually exceed 43 inches; in a greater degree of inter- mingling with other species; and in its replacement by other species in moderately sheltered as well as in sheltered situations. The account given by Eyre and Stephenson (1938) makes it clear that in the Durban area the plant has shown a further decline from its optimum condition. It is still smaller in size (less than three inches), it is less important in relation to other species growing at the same intertidal level and is less frequently a dominant species.
The Morphology, Geographical Distribution and Ecology 81 of Hypnea spicifera (Suhr.) Harv.
Intertidal Position.
Hypnea spicifera occupies the lower part of the intertidal zone where it is emersed at low water of spring tides, although the greater part of the Hypnea girdle may be regularly washed by the waves. (Plates XVI and XVII.) The Hypnea girdle commonly dominates rocky ridges, the vertical sides of rocky platforms, the walls of gulleys, and the roofs of overhanging ledges. The upper part of the girdle which usually lies above wave action at low water of spring tides may be subjected to constant spray. The lower part of the girdle is almost always subjected to very severe pounding by the waves. Hypnea spicifera grows also at corre- sponding levels on isolated rocks beyond the intertidal belt. It extends into the sublittoral to only a limited extent. It is not typically a rock pool species, but where it occurs it grows just below the surface of the water. It is always attached to a firm substratum, usually to rock, sometimes to mussels. It can withstand being partially buried in sand.
Ecological Status.
In the region of optimum development Hypnea spicifera not only dominates, but forms almost pure communities. This can be accounted for by certain features of the prostrate system. This system consists of an intricate network of creeping axes, from which numerous branches spread out in all directions covering the substratum. These creeping axes are anchored by minute, more or less circular discs (haptera) which arise at irregular intervals from the branches. (Fig. 6.) Numbers of
Fic. 6. Small part of basal region of Hypnea spicifera, A. Bases of erect fronds. B. Sand grains adhering to discs.
82 The Journal of South African Botany.
erect fronds develop from the creeping axes. By this form of vegetative growth the Hypnea community not only spreads extensively but. is built up in an almost pure state. It would thus appear that the plant is only partly dependent on reproduction by tetraspores and sexual cells.
As explained above, under optimum conditions of sea temperature and exposure, Hypnea spicifera forms dense communities which are almost pure, other species being crowded out. In this respect these communities recall those of Bifurcaria brassicaeformis (Isaac, 1951). Even under optimum conditions there may be some admixture of species at the sea- ward limits of the Hypnea girdle. Thus at East London, one or more of the species Gelidium cartilagineum, G. rigidum* and Ecklonia biruncinata grow alongside Hypnea spicifera at its lowest levels. Again at Port Alfred, clans of Chondria sp. occur in and about the Hypnea girdle as well as to some extent growing among plants of Hypnea spicifera.
Where conditions are less favourable, Hypnea spicifera forms a con- stituent of a mixed algal vegetation. It occurs thus at Gansbaai and Hermanus (Isaac, 1949) but in neither locality is it one of the commonest species. At Rooi Els it is sometimes co-dominant with Gelidiwm cartilagineum. In moderately sheltered places at Port St. Johns Hypnea spicifera may occur as one of a number of species.
Occurrence in Relation to Exposure.
Over most of its geographical range, Hypnea spicifera flourishes best in exposed situations where it withstands considerable battering from the sea. This is most obvious in its major centre of distribution. At East London, Dwesa and Port St. Johns it is chiefly replaced by Caulerpa racemosa var. zeyheri in less exposed situations. At Fish River Mouth, Hypnea spicifera is replaced in more sheltered places by Caulerpa fili- formis. At its western limits of distribution as an ecologically significant species there are indications that Hypnea spicifera favours more sheltered situations or is at least more tolerant of them. In this connection it might be noted that in the very exposed places at Hermanus (Kwaaiwater) it is Plocamium cornutum and not Hypnea spicifera that is the most character- istic species, the latter occurring as a member of the mixed algal vegetation in less exposed situations (Isaac, 1949). Further, most of the secondary centre of distribution occurs in False Bay. It is true that the chief reason why Hypnea spicifera flourishes in the more northern parts of False Bay is the higher sea temperatures but it should be noted that False Bay is also a region of relatively calm waters.
* See note, Isaac, 1953a, appendix,
The Morphology, Geographical Distribution and Ecology 83 of Hypnea spicifera (Suhr.) Harv.
SUMMARY.
The male, female and tetrasporic plants of Hypnea spicifera (Suhr) Harv. are morphologically similar. The plant varies from less than three inches to about 16 inches and more in height and from a bright green to dark olive green, almost black colour. Size and colour variations are related to geographical and ecological factors. Fertile plants are somewhat longer than purely vegetative plants and bear numerous small fertile branchlets (stichidia). The plant consists of an extensive, richly branched prostrate part from which numerous upright richly branched fronds arise. The prostrate part bears numerous small discs by means of which the plant adheres to a hard substrate, usually rock.
Hypnea spicifera, which is of possible economic importance, is dis- tributed over almost the entire extent of the Union coastline but is of ecological importance only in warmer waters. Except locally at the very southern end, it is a rare or occasional species on the west coast which is subject to the influence of the cold Benguela Current. It is ecologically important from a little east of Port Elizabeth (about Boknes) northwards along the east coast of the Union. Along the whole of this coastline it is subject to the influence of the warm Agulhas Current, sea temperatures increasing in a northward direction. In the southern part of this stretch of coast it shows a luxuriant growth and dominates a low intertidal level to the practical exclusion of other species except in sheltered situations. To the north, while remaining an ecologically important species it becomes smaller in size and less important in the seaweed vegetation.
Abnormally high sea temperatures in False Bay immediately east of the Cape Peninsula are correlated with a secondary centre of distribution along the northern and eastern shores of the bay, where Hypnea spicifera again becomes a common or dominant species, although the Hypnea girdle is often narrow.
Hypnea spicifera occurs to some extent in pools and in the sublittoral but it is chiefly found at the lowest intertidal levels. Over the greater part of its distribution range it flourishes in exposed situations. Under optimum conditions it forms dense almost pure communities, this being facilitated by the creeping prostrate part of the thallus. Along other parts of the coast it may be locally dominant or it may be a constituent of greater or lesser importance in a mixed algal vegetation.
ACKNOWLEDGEMENTS.
Some of the data included in this paper are taken from a thesis to be presented for the degree of M.Sc. of Rhodes University by one of the
84 The Journal of South African Botany.
authors (Miss F. Hewitt). We wish to thank Rhodes University for permission to use this information.
We also wish to thank the South African Council for Scientific and Industrial Research for financial assistance which made it possible to ascertain some of the information contributed by the other author.
To Mr. R. Simons we are indebted for Figs. 1, 4 and 5.
LITERATURE.
Borcesen, F. (1934): “Some Marine Algae from the northern part of the Arabian Sea with remarks on their Geographical Distribution”, Det. Kgl. Danske Videnskabernes Selskab Biologiske Meddelelser, vol. X1, 6.
Eyre, J. and StepHenson, T. A. (1938): “The South African Intertidal Zone and its relation to Ocean Currents. V. A Sub-tropical Indian Ocean Shore,” Ann. Natal Museum, vol. IX, p. 21.
Isaac, Wu. Epwywn (1937a): “South African Coastal Waters in relation to Ocean Currents,” Geogr. Rev., vol. 27, p. 651.
———— (1937b): “Studies of South African Seaweed Vegetation. I. West Coast
from Lambert’s Bay to the Cape of Good Hope,” Trans. Roy. Soc.S. Africa,
vol. 25, p. 115.
(1949): “Studies of South African Seaweed Vegetation. II. South Coast: Rooi Els to Gansbaai, with special reference to Gansbaai.” Ibid, vol. 32, p. 125.
———— (1951): “Observations on the Ecology of Bifurcaria brassicaeformis (Kutz.) Barton,” Jour. Ecology, vol. 39, p. 94.
——— (1953): “South African Seaweed Vegetation and future investigations in this field.” Journ. S. African Botany, vol. XIX, p. 59.
STEPHENSON, T. A. (1947): “The Constitution of the Intertidal Fauna and Flora of South Africa, Part III.”, Ann. Natal Mus., vol. XI, p. 207.
STEPHENSON, T. A. and A., and Bricut, K. M. F. (1938): ““The South African Inter- tidal Zone and its relation to Ocean Currents. IV. The Port. Elizabeth District,” Ibid, vol. 9, p. 1.
STEPHENSON, T. A. and A., and pu Torr, C. A. (1937): “The South African Intertidal Zone and its relation to Ocean Currents. I. A Temperate Indian Ocean Shore,” Trans. Roy. Soc. S. Africa, vol. XXIV, p. 341.
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SEAWEED RESOURCES OF SOUTH AFRICA. By Wm. Epwyn Isaac and C. J. Moreno.
(Contribution to a discussion on World Seaweed Resources held at First International Seaweed Symposium, Edinburgh, July, 1952.)
CONTENTS.
PAGE Algin yielding weeds .. be a Se a i ss 85 Agarophytes .. i a, op: bit oe oid ‘ee 87 Species yielding Phycocolloids other than Alginic acid and Agar 88 Miscellaneous .. = he si oe GE - ee 90 Concluding remarks... = ae eo 5 a 90 Summary Si we ne ae ai oe a a 91 Literature He eS bis es eh bi ae Me 91
Precise figures of South African seaweed resources cannot be given since no quantitative surveys have been carried out. Indicative data, however, are available from the records of Vitamin Oils, Ltd., Cape Town. These estimates are based on the amounts of certain species collected at particular localities.
Algin yielding weeds.
Alginie acid can be obtained from Hcklonia maxima, South African Macrocystis, Laminaria pallida, Bifurcaria brassicaeformis and Sargassum longifolium (Lighthelm, von Holdt and Schumann, unpublished paper). The last named species has the lowest content and is not present in sufficient amount to be of commercial value. The last remark applies also to Macrocystis.
As an abundant intertidal species, Bifurcaria brassicaeformis has a restricted geographical range, being abundant only between Cape Town and Cape Agulhas (Isaac, 1951). It is not cast up to any extent and thus would have to be cut from the rocks at low water of spring tides.
Laminaria pallida and especially Ecklonia maxima are abundant and are cast up in large quantities along certain parts of the west coast. Ecklonia is cast up throughout the year and being buoyant because of hollow stipe and float it is cast high up on the shore where most of it remains. Laminaria is cast up after heavy storms, mostly in July and
85
FOR
A. Gracilaria confervoides B. “Kelps, Gigertina radula, Aeodes orbifosa C. Gelidium pristoides
MELKBOSCH CAMPSBAY
EXPLOITED
86 The Journal of South African Botany.
AREAS
SEAWEEDS
Scale in M les
fe) 50 100
Fic. 1. Map showing areas exploited for seaweeds.
August. Lacking the large internal cavities of Ecklonia, it is less buoyant and is cast up lower on the beach, and is removed again to a considerable extent by the outgoing tide. Related to the relatively small seasonal variation in temperature of the colder South African waters in which these kelps grow (Isaac, 1937a, 1937b, 1949) there is no difference in the cast up Ecklonia at different times of year corresponding to the May and winter casts of kelp on British coasts (Newton, 1951). Referring to cast up material of Ecklonia maxima and Laminaria pallida, Shuttleworth (1951, ce, p. 115) writes: “A fairly conservative estimate would seem to put the total quantity of these two weeds annually deposited on our coastline after storms, etc.,at many hundreds of thousands if not millions of tons.” He does not indicate how he arrives at his estimate. Again, there are no critical data on which to base Shuttleworth’s assertion that: “‘Our re- sources are almost certainly greater than those of Scotland”! (Ibid, p. 116.) It is clear, however, that there are large quantities of sublittoral kelp westwards from Cape Agulhas. Thus from five localities only (Melkbosch, Kommetje, Plaatboom Point, Onrust and Gansbaai) 6,000 tons dry weight (about 15 per cent. water) of cast up kelp, mostly Hcklonia, can be collected annually. These localities (Fig. 1) represent but a small part of the total coastline along which kelps grow but much of the west coast is very inaccessible for the commercial collection of cast up kelp. Also the distances and lack of transport facilities involved would make it un- economical to convey seaweed from remoter parts of the coast.
1 Although available data will not allow of a clear refutation, there can be no doubt that Shuttleworth exaggerates the quantities of kelp on South African coasts.
KE! RIVER M7
Seaweed Resources of South Africa. 87
Agarophytes.
Agar can be obtained from the following species: Gelidium cartilagineum, G. pristoides, Gracilaria confervoides and Suhria vittata (Isaac, Finlayson and Simon, 1943). Fox and Stephens (1943) reported agar from these species as well as from Caulacanthus ustulatus and Hypnea spicifera but their paper contains no details regarding the products extracted. Isaac et al. (1943) showed that the Hypnea spicifera extractive is not a true agar. It was also reported that the agar extracted from Gelidiwm pristoides was of inferior quaility, but subsequent work at Vitamin Oils, Ltd. has shown that a high quality agar is obtainable from this plant. Agar might be extracted from other South African species, including species of Gelidium, but these plants are either too small or not present in sufficient amounts to make them valuable commercially. Gelidiwm corneum was listed for South African coasts by Delf and Michell (1921) and Fox and Stephens (1943) reported that there is some evidence that it may occur on the coasts of the Eastern Province. Papenfuss (1943) refers to a species of Gelidium from the east coast of South Africa which “has been referred to Gelidiwm corneum by some authors and to G. rigidum (now Gelidiella acerosa) by others, but the writer is still uncertain of its identity” (p. 91, footnote 6). Newton (1951, p. 118) wrongly reports Isaac as indicating that G. corneum occurs on South African coasts. Thus it is still uncertain whether the species occurs on these coasts and in view of investigations carried out over an extensive range of South African coasts it is clear that it is not a common species.
Caulacanthus ustulatus, Gelidium cartilagineum and Suhria vittata do not occur in sufficient amounts to be commercial sources of agar. G. cartilagt- neum is a smaller and less luxuriant plant on South African coasts than on Californian coasts and diving operations have shown that it does not extend into the sublittoral in the way that the Californian plant does. On South African coasts it is also frequently found growing alongside the species which has been known here as G. rigidum? with which it can sometimes be confused by harvesters. @. rigidum yields only a small amount of low grade agar. Thus as the picture is at present known, the two commercially important agarophytes are G. pristoides and Gracilaria confervoides. The latter gives in some respects a relatively inferior agar but has the advantage of being cast up in very large amounts in the Saldanha—Langebaan area. About a thousand tons of dry weed is cast up annually in this region. It occurs also at Hout Bay and at Luderitz but in much smaller amounts. Thus the first area named was, and remains, the source of the commercial
2 The South African plant known as Gelidiwm rigidum (now Gelidiella acerosa; see Papenfuss, 1943) seems to be Gelidium amansii. (Papenfuss, 1951).
88 The Journal of South African Botany.
seaweed. Originally South African agar was obtained exclusively from this species but since 1951 agar has been obtained commercially from this species and from Gelidium pristoides*. The latter species is not cast up and has to be picked from mid-tide levels. It is widely distributed on South African coasts in moderately warm waters. It has been collected commercially from Hamburg to Kei River mouth (about 70 miles of coastline) at the rate of about 80 to possibly 100 tons dry weight per annum. Unfortunately no data are at present available regarding its rate of growth and seasonal reproductive cycle although work in regard to the latter is in hand.
The full story of South African Gracilaria confervoides has not been elucidated but Shuttleworth’s account is not correct. Shuttleworth (195lb) seems to assume that the account given for North Carolina material (Causey et al., 1946) is true for South African Gracilaria but this isnot so. Apart from cast up weed this plant occurs at Saldanha—Lange- baan floating in the water and on sand banks where it is weighted down by sand or entangled with mussels. A fuller account will be published later but the chief results obtained are indicated below:
(a) Only small amounts of attached plants have been found?.
(6) Freshly cast up material, sandbank material and floating material will grow vegetatively in frequently changed sea water in the laboratory.
(c) Fertile as well as sterile material is used for agar manufacture.
It may be noted that only sterile plants of Gracilaria confervoides are used for the manufacture of agar in eastern U.S.A. (Causey et al., 1946).
Species yielding phycocolloids other than Alginic acid and Agar.
The chief South African sources of phycocolloids other than alginic acid and agar at present known are Aeodes orbitosa, Gigartina radula and Hypnea spicifera. The properties of Hypnea spicifera extractive have been discussed by Shuttleworth (195la) and the distribution of this abundant South African seaweed has been outlined by Isaac and Hewitt (1953). More research, however, needs to be carried out on the extractive and the technology of extraction.
Aeodes orbitosa is found in cold and moderately cold water. It occurs in the lower parts of the mid-tidal level. It is often a relatively small plant but it may attain lengths of 2—3 feet. In some localities (Melkbosch, Kommetje, Camps Bay, Gansbaai) it is a common or abundant species.
3 For reasons not connected with the quality of the agar, this species is not being harvested at present.
No attached plant or basal attaching dise had been found when this paper was presented in July, 1952.
Fic. 2 A. Aeodes orbitosa showing holdfast.
Vy, SS \ Ds / =\ sot \ | Ne ae PY \ \ 7 ‘Tg i [ e 20 a L TINCH > Seole
Fig. 2B. Iridophycus capensis showing holdfast and stipe.
90 The Journal of South African Botany.
Its general appearance is similar to that of Iridophycus capensis, which seems to have a similar vertical and geographical distribution. Iridophycus tends to be darker in colour and does not grow to the maximum dimensions attained by Aeodes orbitosa. The two plants can be distinguished by their basal parts. Aeodes orbitosa has a simple, relatively large and strong hold- fast so that the plant is not easily detached from the rock (Fig. 2A). Iridophycus has a smaller holdfast which in general grips the rock less firmly and it also has a more or less distinct short stipe which is more or less distinctly canaliculated (Fig. 2 B). A stipe is completely absent in Aeodes. Except locally, Aeodes is much more abundant than Iridophycus. More information, however, is needed on the ecology of these two plants. Aeodes has been used successfully for copper fining of beer but it is not sufficiently abundant to be of industrial importance.
Dried Gigartina radula is also excellent material for beer fining and has already been exported for this purpose. It occurs at lower intertidal levels in places where the coast is sheltered from the full force of the sea and is found on the west coast and in localities as far east as Danger Point. Although it may be absent on many parts of the coast where the seaweeds are exposed to rough seas, it is common in other places. An indication of its abundance is afforded by the claim that up to 100 tons dry weight (20—30 per cent. water) per annum can be obtained from the Peninsula coasts.
Miscellaneous.
The possible use of South African seaweeds as food and as fertilizer was discussed in a previous paper (Isaac, 1942).
Concluding Remarks.
An attempt has been made to give an indication of seaweed resources available for industry in South Africa. More exact surveys are clearly required to give a fuller picture. Where estimates have been given they have been conservative. Fig. 1 helps to put the matter into perspective since it makes clear that only a small part of the total extent of coastline has been exploited for seaweeds. From the data presented it is obvious that considerably more seaweed would be available by collecting over a greater extent of coastline.
Information is needed, however, not only of the amounts available at any given time but also of the rates of growth since it is possible that growth rates will be higher for example than those of British seaweeds. Further, where attached seaweed is harvested, information relating to the annual reproductive cycle is essential if exploitation is to be on a con- servation basis.
Seaweed Resources of South Africa. 91
SUMMARY.
Precise information cannot be given of the seaweed resources of South Africa as no quantitative surveys have been made. Indicative information, however, is available from commercial records of amounts of certain species collected and from known distribution and ecological status of the seaweeds concerned.
The coastline of South Africa is very extensive and only small stretches of it are at present being exploited. The long distances and lack of adequate transport facilities make the exploitation of more inaccessible parts of the coast uneconomical. A further consideration that must be stressed is that more information regarding growth rates and a knowledge of the seasonal reproductive cycles of the exploited species are necessary if exploitation is to be on a sound conservation basis.
Of the algin yielding species large quantities of Laminaria pallida and Ecklonia maxima are available, especially of the latter which is cast up throughout the year. In five localities only, 6,000 tons dry weight of cast up kelps can be collected annually.
Gracilaria confervoides is a commercially important agarophyte. About 1,000 tons dry weight of the species is cast up annually in the Langebaan —Saldanha area. Gelidiwm pristoides is also possibly a commercially important agarophyte. There is no clear evidence of Gelidiwm corneum on South African coasts.
Aeodes orbitosa and Gigartina radula have been successfully used in the copper fining of beer and the latter species has been exported for this purpose. These species are not present in large amounts.
ACKNOWLEDGEMENTS.
Thanks are due to Mr. R. Simons for drawing Figs. 1 and 2 and to Dr. R. F. Milton for his comments on this paper.
LITERATURE.
Causey, N. B., PryrHercs, J. P., McCasxi11, J., Hum, H. J. and Wo tr, F. A. (1946): “Influence of Environmental factors upon the growth of Gracilaria confervoides,” Duke University Marine Station, Bull. No. 3, p. 19.
Detr, E. M. and MicuHett, M. R. (1921): “The Tyson Collection of Marine Algae,” Ann. Bolus Herbarium, vol. 3, p. 89.
Fox, F. W. and Strepuens, E. (1943): “Agar from South African Seaweeds,” S. Afr. Jour. Sci., vol. 39, p. 147.
Tsaac, Wm. Epwyn (1937a) “South African Coastal Waters in relation to Ocean Currents,” Geogr. Rev., vol. 27, p. 651.
(1937b): “Studies of South African Seaweed Vegetation. I. West Coast from Lambert’s Bay to the Cape of Good Hope.” Trans. Roy. Soc. S. Africa, vol. 25, p. 115.
92 The Journal of South African Botany.
(1942): ““Seaweeds of possible economic importance in the Union of South Africa,” Jour. S. Afr. Bot., vol. 8, p. 225. (1949): “Studies of South African Seaweed Vegetation. II. South Coast: Rooi Els to Gansbaai, with special reference to Gansbaai,”’ Trans. Roy. Soc. S. Africa, vol. 32, p. 125. (1951): “Observations on the Ecology of Bifurcaria brassicaeformis (Kiuitz.) Barton,” Jour. Ecol., vol. 39, p. 94. Isaac, W. E., Frntayson, M. H. and Simon, M. G. (1943): “Agar from South African Seaweeds,” Nature, vol. 151, p. 532. Isaac, W. E. and Hewirt, F.: “The morphology, geographical distribution and ecology of Hypnea spicifera (Suhr), Harv.” This Journal. vol. 19, p. 73. LiGHTHELM, S. P., von Hoxp7, M. M., and Schumann, H. I.: ‘““The Composition of some South African Phaeophyceae,” paper presented to First International Seaweed Conference, Edinburgh, 1952. Newton, L. (1951): Seaweed Utilization, London. Papenruss, G. F. (1943): “Notes on South African Marine Algae, II,” Jour. South African Bot., vol. 9, p. 79. (1951): ““Notes on South African Marine Algae, III,” Ibid, vol. 17, p. 167 SHUTTLEWORTH, R. G. (1951): “The Industrial potentialities of South African Sea- weed,” S. Afr. Industrial Chemist, vol. 5. (a) “Part 2, Carrageenin and related products,” p. 76. (b) “Part 3, Agar,” p. 88. (c) “Part 4, Algin,” p. 115.
ON THE HISTORY OF PLANT STUDY UPON THE WITWATERSRAND.
By H. B. Giniimanp. Department of Botany, Witwatersrand University.
The history of the study of the botany of an area begins with the identification and study of the plants which grow there. Should fate decree that the area should subsequently be industrialised, it is but natural that interest should swing to those plant activities which best serve the needs of the industrial community. The march of events upon the Wit- watersrand has followed this course, and it is time that the early botanical events of this region were recorded.
The Witwatersrand area may be variously defined; most simply as the watershed between the Indian Ocean drainage (the Limpopo River) and the Atlantic Ocean drainage (the Vaal River) of southern Africa; most conveniently as the region of the gold mines of the Rand. It is approximately 2,500 sq. miles. Specifically Pretoria in the north, Vereeniging in the south and Heidelberg in the south-east are excluded.
First settled by a European population in the early 40’s of the nineteenth century, it remained a sparsely peopled farming area until the finding of gold and the founding of Johannesburg in 1886 (Gray, 1937). Thereafter its history botanically falls into four periods; the Republican period terminating in the Anglo- Boer War; the colonial period terminating in the formation of the Union of South Africa; the early period of Union, culminating in the First World War, and the local development period
whose first chapter may be said to have concluded with the Second World War.
The Early Period (pre-1886).
No botanical collector seems to have investigated the Witwatersrand in this period. To the north of the escarpment in the valley of the Jukskei River it seems probable that Capt. Cornwallis Harris hunted in pre- republican days. In 1911 Mr. W. Nelson records the finding of Bowiea volubilis Harv. at Blaauwbank near Krugersdorp “35 years before’, i.e. in 1876 and there is a specimen collected by him in the herbarium of the Transvaal Museum, Pretoria, labelled ‘““Nelson 514. Yukskyt River. Dec. 1877. Limpopo Sources” of Potamogeton nodosus Poir. Since local tradition associates the Witpoortjie stream and falls with the “Limpopo
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Sources” this, in all probability, was in our area. Nelson subsequently became a nurseryman operating the Nelsonia Nursery in Booysens, Johannesburg.
The Republican Period.
The early gold discoveries led on to the find of the conglomerates of the Reef, and it soon became clear that gold mining on the Witwatersrand was an enterprise of considerable importance—slowly it began to be realised of some permanence. The early mining town gradually became transformed into the embryo of the city of today and in the process a variety of services grew up, notably those of banking, law and explosives manufacture. I have singled out these three more especially because it is from their ranks that the persons with the interest to make the first serious botanical collections upon the Rand emerged.
The Galpin-Gilfillan Family.
The first Witwatersrand plant of which I can find mention in the literature is an orchid, Habenaria galpini Bolus (H. fetrapetala var. galpini Bolus) described by Dr. H. Bolus in Part I of his first volume of “TIcones Orchidearum Austro-africanarum t. 17 (1893)”. The published notes read, “Transvaal Republic: rocky places near Johannesburg, alt. about 1850 m.; fl. March. E. E. Galpin, 392”.
Mr. Galpin was a bank manager from Queenstown who was early transferred to the Transvaal. The story is best described in the words of his son, Mr. E. A. Galpin of Mosdene, Transvaal, who writes to me as follows:—
“Dr. Galpin was a banker by profession and had 40 years’ service mostly as manager in various parts of the country, in the Oriental Banking Corporation until it was absorbed by the Bank of Africa, and throughout this Bank’s complete history until it was in turn absorbed by the National Bank, retiring from this bank in 1918. Thus a great deal of his</