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TRANSACTIONS
OF THE
American Microscopical Society
VOLUME XXXII
1913
iP ok
TRANSACTIONS
OF THE
American Microscopical Society
ORGANIZED 1878 INCORPORATED I8gI
PUBLISHED QUARTERLY
BY THE SOCIETY EDITED BY THE SECRETARY
See VOLUME XXXII LG
NuMBER ONE
Entered as Second-class Matter December 12, 1910, at the Postoffice at Decatur, Iill- nois, under act of March 3, 1879.
DecaTur, ILL. Review PRINTING & STATIONERY Co. 1913
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PRR UR ARE? Aine Pui, “0 Sesame Mee He <“ Es LE em
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OFFICERS. President: F. CREIGHTON WELLMAN, M. D................ New Orleans, La. First Vice President: F.C: Wattt, Ph:D...........s.0----- Cleveland, Ohio Second Vice President: H.E. Jorpan, Ph.D............. Charlottesville, Va. I ERELATY 20 | Vat NV GeATICOWIAW IE Mtctarerss 20a, aay etal -a\evs 1s 5: o.01 os Sreemenersieraie sete Decatur, Ill. DFCASUKET Als DELANERANGONP aera 8 5 alt tescye o's's\s s «a's ROMO Ore Charleston, Ill. Custodian: MAGNUS PReAUMee tre tee ch A oiscw cscs 6 25 mene Meadville, Pa.
ELECTIVE MEMBERS OF THE EXECUTIVE COMMITTEE
Rech. SHANG atte coe cote ne hee Bureau Plant Industry, Washington, D. C. LR RS Se oe See ee eee ne SP ee ae oO Tee Manhattan, Kans. GO ABC Trerefil Pe Ie ee Oe eae are eRRI rers Se Granville, Ohio
EX-OFFICIO MEMBERS OF THE EXECUTIVE COMMITTEE Past Presidents still retaining membership in the Society
R. H. Warp, M.D., F.R.M.S., of Troy, N. Y., at Indianapolis, Ind., 1878, and at Buffalo, N. Y., 1879. Apert McCatta, Ph.D., of Chicago, II. at Chicago, Ill., 1883 T. J. Burritt, Ph.D., of Urbana, IIl., at Chautauqua, N. Y., 1886, and at Buffalo, N. Y., 1904. Gro. E. Fett, M.D., F.R.M.S., of Buffalo, N. Y., at Detroit, Mich., 1890. Stmon Henry Gace, B.S., of Ithaca, N. Y., at Ithaca, N. Y., 1805 and 1906. A. Ciirrorp Mercer, M.D., F.R.M.S., of Syracuse, N. Y., at Pittsburg, Pa., 1896. A. M. BueiLe, M.D., of Columbus, Ohio, at New York City, 1900. C. H. EicENMANN, Ph.D., of Bloomington, Ind., at Denver, Colo., 1got. Cuartes E. Bessty, LL.D., of Lincoln, Neb.,
at Pittsburg, Pa., 1902. E. A. Birge, LL.D., of Madison, Wis.,
at Winona Lake, Ind., 1903. Henry B. Warp, A.M., Ph.D., of Urbana, Ill, at Sandusky, Ohio, 1905. Hervert Oszorn, M.S., of Columbus, Ohio,
at Minneapolis, Minn., Igto. A. E. Herrzier, M.D., of Kansas City, Mo., at Washington, D. C., tort. F. D. Heatp, Ph.D., of Philadelphia, Pa., at Cleveland, Ohio, 1912.
The Society does not hold itself responsible for the opinions expressed by members in its published Transactions unless endorsed by special vote.
TABLE OF CONTENTS
FOR VOLUME XXXII, Number 1, January, 1913
Dissemination of Fungi Causing Disease, by F. D. Heald (Presidential PGULeSGL EOD TOUS) Geisheels's.a wie» bra, ules Soak & Pacetneseaaen ele te ec © waa
Periodicity of Algae in Illinois, 8 Text Figures, by Edgar Allen Transeau
Nature and Classification of Plant Rusts, 5 Text Figures, by Frank D. BEOER eRik oh cee sis Cities Seu mide Suehedle susie Bhs LER ee ee eee
Notes and Reviews—Notes on Some Peculiar Sense Organs in Diptera (illustrated) ; Convenient Dropper for Use in Cutting Celloidin Sec- tions (illustrated) ; Critical Illumination for the Microscope; Clean- ing Diatoms; Staining Protozoa; Double-stain Method for Polar Bodies in Diphtheria Bacilli; New Technic. in Staining Diphtheria Specimens with Toluidin Blue; Notes from the Meeting of the Illinois Microscopical Society; Bog Solutions and Plants; Effects of Cropping on Soil Bacteria; Alternation of Generation in the Phaeo- phyceae; Experiments on the Germination of Teleutospores; Direc- tion of Locomotion in Starfish; A Rotifer Parasitic in Egg of Water Snails; Englenids and Their Affinities; An Ameba with Tentacles; Some American Rhizopods and Heliozoa; Size of Chromosomes and Phylogeny; Spermatogenesis in Hybrid Pigeons; Male Germ Cells in Notonecta; Interstitial Cells of Testis and Secondary Sex .Char- acters; Microbiology in Relation to Domestic Animals; Beginners’ Guide to the Microscope; Microscopy and Drug Examination.......
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31
41
TRANSACTIONS
OF
American Microscopical Society
(Published in Quarterly Installments)
Vol. XXXII JANUARY, 1913 No. 1 THE ADDRESS OF THE PRESIDENT FOR 1912
THE DISSEMINATION OF FUNGI CAUSING DISEASE By F. D. HEALD
INTRODUCTION
A great deal has been written concerning the dissemination of seeds and this topic constitutes one of the regular subjects for treat- ment in every text book of elementary botany, but the dissemina- tion of fungi is rarely mentioned. Even the text-books on fungi or plant diseases give but an inadequate account of this phase of mycology. Observations and experiments show that fungi pro- vide for the dissemination of their offspring and the perpetuation of the species in many and varied ways and in many cases with great effectiveness. It is undoubtedly true that the agricultural and commercial practices of our present civilization have very materially assisted nature in spreading broadcast numerous para- sitic forms as well as countless numbers of harmless saprophytes. That fungus pests are more numerous now in this country than in former years is not imaginary, but a stern reality. It is true that with the rapid development of plant pathology during the last decade we have had diseases of plants brought to our attention more than ever before. The history of our agriculture shows that with the intercourse between nations, fungus pests have been fre-
6 F. D. HEALD
quently transported from one country to another. It is my purpose to consider briefly some of the ways by which fungi, and especially those causing disease, have been and are being disseminated.
HOW FUNGI ARE CARRIED
In the first place brief reference may be made to the state in which fungi exist during their transport. They may be carried as spores, as sclerotia, or as mycelium. Most fungi produce from one to several different kinds of spores, or specialized reproductive bodies, which provide for the perpetuation of the species, just as seeds of our Spermatophytes provide for the production of more seed plants. Spores may be active, that is, motile or capable of locomotion, but in most cases they are not endowed with the power of movement; in the former case their own activity may carry them in an aqueous medium to points far away from the parent plant that produced them, but in the latter they must be transported by some outside agency.
Spores are produced by fungi in enormous numbers. It is un- doubtedly true that vast numbers of spores perish without ever finding suitable conditions for the production of new plants. It has been estimated for some species of mushrooms that only one spore out of twenty billion ever produce a new plant capable of spore production.t Many contain a minimum of reserve food and become exhausted in their first attempt to establish themselves ; some are not able to withstand adverse conditions, such as desiccation, low temperatures, etc.; certain types germinate at once without a resting period and thus frequently fail to reach a suitable sub- stratum upon which to develop. Conidiospores may germinate at once and they are generally produced in much greater numbers than the more resistant ascospores which frequently require a resting period. Figures give but a slight conception of the enormous num- bers of spores produced by fungi but they serve to emphasize their prodigality in spore production. It has been determined by careful analytic methods that a small “spore horn” or “tendril” of the chest- nut blight fungus may contain as many as 115,000,000 pycnospores. Cobb states that a single head of smuted oats may contain as many as 500,000,000 spores, or a sufficient number to give 1000 per square
DISSEMINATION OF FUNGI ye
foot if they were scattered evenly over an acre of ground. The marvel is that chestnut blight has not become more widely dis- seminated or oat smut a greater pest. Buller’ estimates that a single wheat “berry” affected with bunt or stinking smut may contain over 12,000,000 spores; also that a single fruit body of Polyporous squamosus produced 11,000,000,000 spores, while the giant puff ball, Lycoperdon bodista L. produced the enormous number of 7,000,000,000,000 spores.
The production of sclerotia, or dense aggregates of fungus tissue by fungi is not uncommon, and these structures vary from minute masses to organs of appreciable size. Some fungi which produce spores but rarely, rely upon sclerotia for carrying the species over unfavorable conditions or for dissemination, while in other cases as in ergot, the sclerotium is only one stage in a rather complex life cycle. The origin of sclerotia is perhaps not uniform; they are probably due, in some cases, to the sterilization of a spore fruit, a pycnidium or perithecium, and certain fungi with scler- opycnidia suggest this origin. Sclerotia appear to be very effective structures in perpetuating the species, if we may judge from the wide dissemination of certain fungi which are propagated almost entirely by this method. Why more fungi have not discarded the wasteful and uncertain process of spore propagation for the more certain method of sclerotia production can only be conjectured.
Fungi may be transported small or even great distances in the vegetative or mycelial stage. This mycelium may be included with some dead organic material which furnishes the substratum for its development or it may be included within the tissue of a plant or a plant structure upon which it is parasitic.
The following brief outline will give some of the principal ways in which the dissemination of fungi is effected:
I. Seed-borne fungi—Seed dissemination. 1. By true seeds or fruits. 2. By vegetative reproductive structures. Il. Air or wind-borne fungi—Wind dissemination. 1. No explosive apparatus. 2. Provided for by an explosive apparatus. (a) Forcible ejection of the fungus spores from the fun-~ gus fruit.
8 F. D. HEALD
IlI. Water-borne spores—Water dissemination. 1. Active or motile spores. 2. Passive or non-motile spores. IV. Insect-borne fungi—Insect. dissemination. 1. Insects as carriers. 2. Insects as hosts. V. Dissemination by other animals. VI. Dissemination by agricultural and commercial practices. 1. Transport of soil or manure. 2. Transport of infected seed, nursery stock, or hast: cultural stock. 3. Transport of various commodities.
SEED-BORNE PLANT DISEASES
Many fungi have certainly solved the problem of dissemina- tion in a most effective way by a relation to the seed of the host plant at some point in their life history. The fungus may be car- ried in either the spore, sclerotium or mycelial stage, upon or with- in true seeds, fruits or vegetative reproductive structures such as tubers, roots, bulbs, etc. Many of these seed-borne fungi are pernicious pests and have attained as wide distribution as the hosts themselves. Since plant diseases have been more intensively studied, more and more illustrations of seed-borne fungi have been brought to our notice. Some seed-borne fungi appear so constantly and generally upon some of our common crop plants that the attendant symptoms are not unfrequently interpreted by the untrained, as a normal accompaniment.
Anthracnose of the bean was one of the first diseases that was demonstrated to be disseminated by true seeds. This was first proved by Frank? in 1883, although later investigations have re- peatedly claimed the honor. The mycelium of the fungus grows through the pod and into the seed during the period of maturing, and is there ready to resume its growth when the seed germinates. Experiments tend to show that this disease is introduced into a field very largely if not entirely by the ruse of infected seed, and that the spores are not generally spread from one field to another by the wind.* The Ascochyta blight of peas is another disease that behaves in a similar way* and Barre has recently shown that the widely disseminated anthracnose of cotton bolls is of a like nature.®
DISSEMINATION OF FUNGI 9
Since infected seeds, in so many cases, show no external evidence of the disease, the fungus is insured a wide dissemination, even with the most careful practice in the selection of apparently clean seed. Seed-borne fungi do not appear to be confined to any definite groups but this method of dissemination may prevail whenever the ripening ovary is infected. The downy mildew of the Lima bean and the white rust of the oyster plant constitute two excellent il- lustrations from the Peronosporales. The seed of the oyster plant may be so badly infested with the white rust as to entirely destroy the crop. The black-leg or Phoma wilt of cabbage,®° a disease known in this country only during the past few years, was un- doubtedly introduced from Europe with imported seed. Chapman‘ has recently called attention to the seed dissemination of three dii- ferent onion diseases: smut due to Urocystis cepulae; brown mold, caused by Macrosporium porri; and downy mildew, referred to Peronospora schleideniana.
Fruits which function as seeds may also act as carriers of the parasite. Perhaps the best known and most familiar illustrations of this class are the seed-borne smuts of cereals, in which case the fungus is either on the surface of the caryopsis in the spore stage or has penetrated the pericarp and persists as a dormant mycelium. The loose smut of oats and the stinking smuts or bunt of wheat are good illustrations of the former, while the loose smut of wheat is one of the most notable illustrations of the latter condition. The
‘bunt or stinking smut of wheat is undoubtedly more prevalent in
our cultivated wheat fields than any similar species upon a wild host, or at least it was until the introduction of fungus “‘steeps” for its prevention. The ordinary process of harvesting is one that has very materially assisted in the dissemination of the fungus. When a wheat plant becomes infected with bunt every head produced by a single stool is smutted and all the “berries” are destroyed or trans- formed into “smut berries.”” Smutted plants may be scattered here and there through the field, and during the threshing process smut- ted berries are mixed with the normal sound grain; but many of the smut grains have the thin outer membrane ruptured, thus setting free the spore mass and the individual spores become scattered over ~ the normal grains, lodging particularly in the “brush” and in the
10 F. D. HEALD
suture.s Wheat may be so badly smutted that the normal grains are discolored by the large numbers of smut spores adhering to the berries. Of course nobody would think of using such grain for seed, but unfortunately smut spores may be present in minute quantity without giving any indication of their presence. It is pos- sible, however, for the scientist to determine whether seed wheat is infected with bunt to even a slight extent. If the seed is washed or scrubbed in sterile water, the washings centrifuged, and the sedi- ment examined with the microscope, the presence or absence of smut spores can be determined. This method was first used in this coun- try by Bolley.®
In the loose smut of wheat wind dissemination of spores is combined with seed transport of the dormant mycelium. The inflor- escence of wheat is completely destroyed and the dry, powdery mass of spores scattered by the wind. This maturity of the smut coin- cides nearly with the blossoming time of the normal head and the scattered spores may be responsible for a blossom infection. The fungus penetrates the developing ovaries and remains as a dormant mycelium hidden within the seed and exhibiting no warning of its presence. It is there, however, ready to resume activity with the awakening of the seed. Two diseases of beets are known to be car- ried by the seed (fruits): the Phoma rot of beets which has been so prevalent in Europe, and our well-known Cercospora leaf spot. The fungus (Phoma betae) which causes a rotting of the maturing beets also causes a serious damping-off of young seedlings.1° A re- cent illustration has come to the writer’s attention of chestnuts bearing the sclerotia of a fungus upon the surface.
Fungi which cause disease may be disseminated by the use of infected vegetative reproductive structures such as tubers, roots, rhizomes, bulbs or corms, for the production of a new crop. All such structures are gorged with reserve food and their tissues in a semi-dormant condition, easily invaded by certain types of fungi. In the majority of these structures the presence of an internal in- fection is revealed by some discoloration or disorganization of the storage tissue, or the fungus may be more superficial and exist in either the mycelial or the sclerotium stage. The Irish potato stands preeminent among the cultivated plants, for its numerous tuber-
DISSEMINATION OF FUNGI Il
borne diseases.. In recent years many of these tuber-borne dis- eases have made such headway as to seriously threaten the potato growing industry in many parts of the country. Mention may be made of the late blight of the potato with its internal mycelium, the dry rots which also produce internal discolored areas pervaded by mycelium, scab with the more superficial corroded areas, potato wart with its external warty excrescences, and Rhizoctonia or po- tato rosette with superficial sclerotia. It has been shown by Massee that wart may also be transported by the use of tubers which show no external evidence of the disease, the spores being lodged in the “eyes.” Some of these tuber-borne fungi may so exist in the soil as to infect perfectly healthy seed, but their original introduction can be traced in numerous instances to the use of infected seed.
The sweet potato affords several illustrations of diseases which are frequently introduced by the use of infected seed roots. Among these may be mentioned the black rot, due to Sphaeronema fimbri- atum.1+ Several onion diseases may be introduced into new fields, by the use of infected sets or the use of imported bulbs for growing seed. Disease of the gladiolus are spread by the planting of corms already infected, and the same may be said concerning the bulbs of various greenhouse plants. As specific examples of bulb-borne diseases mention may be made of the Japanese lily disease, due to Rhizopus necans, and the anther smut of Scilla latifolia which de- velops from mycelium present in the bulb.
AIR OR WIND DISSEMINATION
The spores of many fungi are carried away from the parent plant by means of air currents. In general it may be stated that spores which are adapted to wind dissemination are liberated from the fungous fruit as a dry, powdery mass or are born singly or in loosely connected chains upon the ends of aerial sporophores, from which they are easily detached. The minute size of fungous spores makes unnecessary special devices for rendering them buoyant, and it is always possible to obtain various forms from the dust that settles to the surface of objects in closed rooms or in the garden or fields. The majority of the air-borne spores appear to be those of harmless saprophytic forms, and many of the statements made
I2 F. D. HEALD
concerning the part which wind plays in the dissemination of para- sitic species are based largely on analogy rather than supported by direct experimental evidence.
Observational evidence is of little value in determining the part of air transport of fungus pests which are confined to a single host, but some heteroecious rusts give us undoubted examples of wind dissemination which so far as I know have never been defi- nitely proved experimentally. The cedar rust which alternates be- tween the cedar tree and the apple tree, and must pass from one to the other, is an excellent example. Susceptible varieties of apples standing adjacent to infected cedars will show a high percentage of infection, sometimes as many as 200-300 distinct spots to each leaf and the number of infections per leaf will decrease with the dis- tance until the average is either one or less to each leaf. In addi- tion, the rapidity and universality of the infection following the gelatinous stage of the cedar apple can be explained in no other way than by the wind dissemination of the sporidia, which Coons’? has shown are forcibly discharged from the promycelia. The part which wind plays in the spread of our cereal rusts has probably been greatly overestimated. The old idea that rusts are spread gradually by the wind from the southern plains country to the north as the season progresses, has been largely abandoned as our ideas of their life habits have been modified. The theory of the wind dissemination of the cereal rusts gives a beautiful example of the inefficiency of reasoning alone as applied to the processes of nature.
It is undoubtedly true that many of our present day state- ments in regard to wind dissemination of spores would need re- vision if the rigid test of experimental evidence were applied to them. The application of scientific methods to the determination of the part which wind plays in the dissemination of parasitic fungi opens up an interesting field for investigation. It may not be amiss to mention briefly some of the methods which may be utilized, and it may be stated at the beginning that. these have already yielded valuable results in the few cases where tried.
In the employment of the exposure plate in the field under natural conditions the pathologist is but imitating the bacteriologist.
DISSEMINATION OF FUNGI 13
As far as I have been able to determine this method was first em- ployed in this country in the field for determining the prevalence of parasitic fungi by Wolf** at the writer’s laboratory in 1907. It had, however, previously been used by Saito in Japan. It should be emphasized in this connection that the exposure plates should be made under natural conditions if we are to obtain reliable re- sults. Erroneous conclusions may be drawn from results obtained under artificial conditions even if they are obtained from field ex- periments. It is evident that this method is of value only when the spores of the pathogens under investigation will germinate upon the medium that is available. There are many parasitic forms the spores of which will not germinate upon the ordinary culture media, and in investigating the prevalence of these spores this method is clearly at fault. Exposure plates may be made in the field or in the laboratory with the substitution of an artificial air current. As an illustration of this type, the experiments of Ful- ton** with the spore horns of the chestnut blight fungus may be mentioned, although his negative conclusions would have been ob- tained by a priori reasoning.
It is at once evident that the exposure plate can give no exact quantitative results, but only the relative abundance of the forms obtained. The aspiration of the air through a “spore trap” and the determination of the number of spores per unit quantity of air can be readily performed by the employment of the ordinary bac- teriological method. This method was used by Wolf in 1907 and has recently been employed by Anderson. The poured plates in this method do not reveal the possible presence of spores which will not germinate upon our culture media. In order to determine the presence of these, other methods must be employed. There are two methods suggested which are somewhat comparable to the two just outlined. First, if quantitative results are not desired a glass funnel, the inner surface of which is coated with glycerine, may be exposed for a certain length of time in the open and the spores which fall into it washed down with sterile water and the washings centrifuged, after which the sediment thrown down may be ex- amined with the microscope. If quantitative results are desired the aspirator should be used, the contents of the sugar tube dis-
14 F. D. HEALD
solved in a known volume of sterile water, all or a unit quantity centrifuged and the sediment examined microscopically by the use of the Leitz-Wetzlar counting apparatus. The results of the micro- scopic tests may be substantiated by inoculations made by using a suspension of the spores obtained from the air analyses, and in certain cases this method can be used to good advantage.
Inoculations by wind-borne spores under controlled conditions has been used in some cases for determining the part which this method of transport of spores plays in the life history of the fungus. As an illustration, the inoculations with chestnut blight fungus made by Anderson may be cited. The wounds were protected so as to exclude insects and spores washed down the tree by rains.
A large number of fungi, the spores of which are disseminated by air currents, produce the spores in such a manner that they are easily detached and carried away by the wind or in a dry powdery mass. In such cases there is no explosive apparatus that ejects the spores into the air and it is entirely the force of air currents that sweep them away from some exposed position, or they are borne in such a manner that they rattle out of the fungous fruit, frequently as a result of agitation of the host plant by the wind.
In many fungi, particularly the ascomycetes and basidiomycetes, the spores are forcibly ejected into the air' and can then be swept away from the fruit by the wind. It should not, however, be con- cluded that all fungous spores that are forcibly ejected, are adapted for wind dissemination. There are numerous cases in which the forcibly ejected spores are not adapted for wind dissemination but after they have come to rest are removed to more distant locations by other agencies.
The loose smuts of cereals and other grasses which produce myriads of spores in the deformed or destroyed inflorescences of their hosts are supposed to be disseminated largely by wind-borne spores. The powdery condition of the spores, and their elevated position upon the host certainly suggests this method of transport. The uredospores and aecidiospores of many rusts and particularly the sporidia are wind-borne, while the summer spores of the powdery and downy mildews are produced in such a way as to suggest this method also. The aecial stage of Gymnosporangium
DISSEMINATION OF FUNGI 15
macropus shows an interesting adaptation.‘* During dry weather the segments of the pseudoperidium are curved outward in stellate form but during humid or rainy periods they approach each other and partially or completely close over the spores. The spores are thus set free at a time when they are most likely to be carried away, and this is especially important in heteroecious forms which must reach the alternate host or fail to develop.
Judging from the results of experiments in the field it seems that the most prevalent spores belong to species of the imperfect fungi, and especially to the Hyphomycetes. Perhaps these facts are to be explained by the omnipresence of certain species of this group rather than to the fact that they are better adapted for wind dis- semination. In the work carried out by Wolf only a single pycnidial form, Phyllosticta, was obtained during a long series of orchard tests. The work of Burrill and Barrett'* on the wind dis- semination of Diplodia zeac, the fungus causing dry rot of corn, may be mentioned in this connection. They found by field tests that spores of this fungus were carried by the wind and they at- tribute much oi the infection to wind-borne spores from old stalks. There appears to be little direct experimental evidence to show to what extent ascomycetes which forcibly eject their spores from the asci are disseminated by the wind. In many cases the ejected spores are surrounded by a sticky material and a priori reasoning would suggest that in such cases they are not extensively carried by the wind. It is at least suggestive that the spores of ascomycetes are obtained so rarely in exposure plates in the open. Further in- vestigations may show that ascospores are more generally scat- tered by the wind than present experiments show. It is the idea of the writer that wind-borne ascospores may be responsible for the spread of a fungus in the immediate environment, but that long jumps or wider dissemination are accomplished by other agencies than the wind.
The puffing of spores as in Peziza, Urnula, and other Dis- comycetes in which there is a simultaneous discharge of numerous asci, is undoubtedly an adaptation for wind dissemination. Since most of these fruits are produced close to the ground, the forcible expulsion of the spores must materially assist in their being car-
16 F. D. HEALD
ried away by air currents. In the Hymenomycetes the forcible ex- pulsion of the basidiospores from the sterigmata helps simply in liberating the spores from the sporophores, while the normal posi- tion of the hymenium makes the fall of the spores inevitable, and convection currents assisted by wind carry them away to more distant points.
Spores that are destined for wind transport may be set free in a cloud by the explosion of the fruit of the host plant. A beautiful illustration of this is to be found in the smut infected fruits of Oxalis, which burst and liberate the spores in much the same way that the capsules of touch-me-not expel their seeds.
DISSEMINATION BY WATER
Liquid water plays a very important part in the dissemination of some disease fungi. In certain groups of fungi free water is necessary for the development of some stage in the life cycle, that is, in those that produce active or motile spores, swarm spores, or zoospores. These active spores make their way for a shorter or greater distance from their point of origin as a result of their own power of locomotion. In other cases passive or inactive spores may be washed down from the host plant by rains and carried away by natural water currents or spread along the course of irri- gation ditches.
The aquatic habit has been retained to a greater or less extent by the various species of the pond scum parasites, the water-molds, the white rusts and the downy mildews. The parasites of the pond scums are completely dependent upon free water for their dis- semination and this appears to be equally true of some Chytridiales parasitic on seed plants. The natural habitat of the cranberry is particularly favorable for the development of the cranberry gall due to Synchytrium vaccint. It is also noteworthy that Urophlyctis alfalfae has made its appearances in this country in a number of regions in the Pacific coast country where alfalfa is grown under irrigation.
The Saprolegniales or water-molds include a much larger num- ber of saprophytes than parasites and in the majority of forms are strictly aquatic in habit. Some species are parasitic on the eggs
DISSEMINATION OF FUNGI 17
and young of fish and also frequently gain entrance to the bodies of adults. While countless numbers of young fish and other aquatic forms annually fall a prey to the ravages of these fish molds, it 1s under the artificial conditions of the fish hatcheries, that the water molds are most likely to become epidemic. Not only may the water become filled with myriads of these motile spores of the water molds, but the diseased fish may transport the fungus for long dis- tances and introduce it into entirely new localities.
There are two fungi which belong to the water molds that cause destructive plant diseases. One of these, Pythiwm de Bary- anum, is the cause of a damping-off of seedlings, a great variety of species being attached. This fungus has attained practically a world-wide distribution. At just the periods that young seedlings are establishing themselves in the soil, this damping-off fungus finds conditions favorable for the development and dissemination of its swarm spores. These motile spores are able to swim actively in the soil water and are also spread by the spattering of rain and the meteoric water which flows over or through the surface layers of the soil. It is this production of enormous quantities of motile spores at times when the seedlings are young and susceptible that makes this one of the most destructive of the damping-off fungi. The other water mold referred to has been known to science only since 1906,'* but when it first appeared in California it made such headway as seriously to threaten the citrus industries of that sec- tion of the country. The fungus in question, Pythiacystis citroph- thora, causes the disease of lemons known as the brown rot, and the history of the discovery of the cause of this disease and of its method of dissemination forms one of the most interesting chap- ters in modern plant pathology. The natural habitat of the fungus is the damp soil of the orchard, and irrigation apparently favors its development. The spores of the fungus are not wind-borne and only fruit either in contact with the soil or very low down on the tree becomes infected. The motile spores can easily reach fruits in contact with the soil by swimming through the soil moisture, and the spattering of rain is supposed to carry spores to the lowermost fruits that are free from contact with the soil. If lemons were handled like apples in preparing them for the market, the brown
18 F. D. HEALD
rot would never have become such a serious pest, but lemons must be washed or scrubbed, and it is just this process that makes a more extensive infection possible. Dirt bearing the fungus is transported to the washer on the surface of the fruits and the fungus finds in the water of the washer favorable conditions for its development. The washers thus become infected with the fungus and the water through which the lemons must pass becomes filled with myriads of the motile spores, some of which may gain entrance to the fruit during the washing and scrubbing process. Of course greater care is now taken in cleaning the washers and the use of fungicides in the water prevents the development of the fungus.
The Peronosporales, including the downy mildews and white rusts are not so completely dependent upon moisture for the dis- semination of the spores, since their conidia (sporangia) are borne in such a way as to be Carried away by the wind. They do, how- ever, show a greater dependence upon moisture than many of the fungi that have abandoned entirely the production of motile spores. It is an especially noteworthy fact that the late blight of the potato, caused by Phytophthora infestans, is epidemic during wet seasons and is limited geographically by rainfall. This partial dependence upon free water for its development probably explains the reason the late blight has never been a serious potato disease in the drier portion of the plains country.
It is undoubtedly true that rain and water currents play a very important part in the dissemination of fungus spores. In the first place rain may assist in the further transport of wind-borne spores that have been lodged upon plant surfaces. In case of wound in- fections the spores may be finally carried into the wound by rain washing down over spore laden surfaces, the spores finally coming to rest in a more favorable position for germination. Many fungus spores are rarely carried away from the fruits in which they de- velop except through the agency of rain. This seems to be par- ticularly true of many forms producing pycnidia surrounded by a more or less evident mucilaginous secretion which prevents their release from the fruit or their separation from each other except in the presence of sufficient water to dissolve the cementing sub- stances. Such spores may accumulate as sticky or waxy masses
DISSEMINATION OF FUNGI 19
over the acervulus or they may be pushed out through the ostiole of a pycnidium as the result of growth of others within. In certain forms the extruded spore mass takes on the form of a long, coiled, flattened or cylindrical thread, which is designated as a “spore horn” or tendril. These sticky spores are produced in enormous quantities during warm, humid periods and the spore masses dry down and become hard if they are not washed away by rains. Many spores of this type retain their vitality for a considerable period as long as they are embedded in their mycelaginous secretion, but soon succumb to desiccation and other unfavorable factors as soon as they are separated by the rains.
In this connection several illustrations may be mentioned. Valsa leucostoma, the fungus causing die-back of peaches, plum and apricots produces conspicuous, brown or amber-colored ten- drils which ooze out from the pycnidial stromata embedded in the bark. These are always abundant during the humid period follow- ing a rain, but disappear entirely except from especially protected positions during the first precipitation of any amount. During a warm rain the spores are being produced in enormous numbers but they are washed away as rapidly as they are extruded so the ten- drils do not become visible until the rain has ceased. What has been said concerning the conidiospores of the die-back fungus ap- plies equally well to those of the chestnut blight fungus, Endothia parasitica. It has recently been determined by experiments carried out under the writer’s direction that the so-called summer spores are washed down from the blight lesions in enormous numbers, even during the winter rains when the temperature is but little above the freezing point.
There seems to be little evidence that the spores of bean anthracnose are wind-borne. The facts known concerning this dis- ease indicate that rain and dew are of utmost importance in its spread after it has once been introduced by the use of infected seed. The fact that the spores of the Melanconiales are found so infre- quently in the air lends support to the theory that these fungi are largely dependent upon rain and other agencies besides wind for their transport.
There is not much direct evidence to show the part of running
20 F. D. HEALD
water in the transport of non-motile spores. If these spores fall into streams or irrigation ditches there is every reason to suppose they will be transported for some distance. In some forms germina- tion would take place in a few hours, and so the possibility of trans- port for long distances would be excluded. It is claimed that irri- gation water plays a very important part in the dissemination of the late blight of celery in California.** The spores may be washed away from the pycnidia and carried along the trenches with the irrigation water.
INSECTS AND DISSEMINATION OF FUNGI
The relation of insects to the spread of plant disease is a sub- ject to which sufficient attention has not been directed. The nu- merous insect-borne diseases of man and animals suggests a similar relation between insects and plant diseases. In most insect-borne animal diseases the insect acts as an intermediate host, and is not simply a carrier as is true in the case of the “typhoid fly.” Not a single instance of an insect acting as an intermediate host for a fungus causing a plant disease has yet been brought to light, but the part which insects play in the dissemination of fungi is limited by their work as carriers and as producers of wounds which make infection possible.
It seems probable that insects play a very important part in the dissemination of saprophytic fungi. Fungus fruits are in many cases rich storehouses of food, and insects have become mycopha- gists, either utilizing’ the natural growths or becoming cultivators of fungi as is exemplified by the “ambrosia” beetles, or the ants with their fungus gardens. In visits to fungus fruits insects cannot fail to carry away spores, in much the same way that in- sects carry away pollen (spores) from the flowers which they visit. In some cases there seems to be a definite adaptation to insect trans- port of spores, while in others the transport is apparently only acci- dental.
The carrion fungi, of which Phallus impudicans may be tak- en as an example, attract flies to their spore-producing surfaces by their characteristic odor. The greenish slime in which the spores are embedded also contains three sugars, levulose, dextrose, and
DISSEMINATION OF FUNGI 21
another intermediate between dextrose and gum. These and the spores are greedily eaten by flies. Fulton? has shown that flies transport the spores in millions by the adherence of them to their feet and proboscides, and also that the spores will germinate after they have passed through the digestive canal of these insects.
The sphacelia stage of the ergot of rye and other grasses gives a beautiful example of insect dissemination. The ovaries become infected at flowering time by wind-borne ascospores and the pro- duction of conidia soon begins. This production of conidia is ac- companied by the secretion of a sweet substance, the so-called honey dew, which is eagerly sought by insects. A rapid dissemination of the fungus is accomplished since the visiting insects carry away spores and scatter them as they fly from flower to flower. Although the sooty mold of the orange and other citrous fruits is not a defi- nite parasite, it becomes a troublesome pest. This fungus is asso- ciated with and spread by the white fly, or Aleyrodes and other species of aphid-like insects.2* The secretions of sweetish fluid constitutes the pabulum which makes possible the development of the fungus. Some anther-inhabiting fungi are undoubtedly dis- seminated by insects. This is true of the smut of various species of the pink family. The affected anthers produce smut spores in- stead of pollen and these are carried from plant to plant by the visiting insects, thus assisting in the dispersal of the fungus.
The manner of spread of fire blight of the pear and apple was for many years more or less of a mystery. The bacteria causing the disease are set free upon the surface of the diseased parts in sticky droplets, and are quickly killed by exposure to sunlight and desiccation. Waite*® first showed that the rapid spread of the dis- ease during the spring is due to insects and especially to bees. The bacillus lives over winter in only a small percentage of the affected branches and is spread from these by insects. The blossoms be- come infected, the bacteria multiplying in the nectar, and thus the disease is spread from flower to flower by bees. Insects like leaf hoppers and others which bite the delicate young shoots are also important agents in the spread of fire blight.
An intimate relation between certain mites and the bud rot of carnations was established by the writer.2* The mites are always
22 F. D. HEALD
found in the buds that have been rotted by Sporotrichum poae ; they find in the mass of rotted petals a most favorable substratum for their development. The young mites which migrate from diseased to healthy buds carry spores of the fungus with them and thus in- oculate the healthy buds, their presence serving to accentuate the severity of the trouble.
The literature of plant pathology contains not infrequent refer- ence to the part which insects play in the dissemination of plant diseases, but these are in many cases generalizations not based on direct experimental evidence. Murrill and others** have stated that the spores of the chestnut blight fungus are carried by insects, but up to the present date there are no published experiments which really substantiate this statement. It seems probable, however, that this early claim will be supported by experiments now in pro- gress.
Massee”’ has pointed out the fact that the rapid spread of apple canker due to Nectria ditissima in Engiand coincides with the in- troduction and spread of the “American blight or wooly aphis.’”’ He makes the following statement: “I think it would be scarcely an exaggeration to say that if we had no “wooly blight” we should have no “canker,’’* that is in the sense of an epidemic. It should be pointed out, however, that this opinion which is not based on ex- perimental evidence is not entirely acceptable. The whole problem of the relation of insects to plant diseases is one that merits more attention than has been given to it, and investigations in this line may be expected to yield important results.
DISSEMINATION BY OTHER ANIMALS
The prevalent notion in regard to the part which other ani- mals play in the dissemination of disease-producing fungi is ex- pressed by the following quotations:
“Insects, birds, snails and slugs are known to be unconscious agents in the dispersion of spores, whereas dogs, hares, rabbits, etc., running through a field of corn, potatoes or turnips act after the fashion of the wind by bringing into contact adjoining plants.”°
“Mites, flies, birds, mice, etc., carry spores adhering to their
DISSEMINATION OF FUNGI 23
bodies from one place to another; and probably are frequently the unconscious cause of a new infection or the rapid spread of an epi- demic due to fungi.”
While the above are generalized statements based on but little experimental evidence this possibility has been demonstrated in some cases. Massee reports that snails and slugs are instrumental in spreading powdery mildews. Slugs allowed to crawl over mil- dewed leaves and then over healthy leaves left behind spores which soon caused the appearance of mildew along their pathway.
Birds, especially woodpeckers, have been mentioned by var- ious writers in connection with the dissemination of the chestnut blight fungus. While the few tests reported to date (15) were negative it seems reasonable to believe that bird transport is a possibility. Woodpeckers frequently visit the chestnut blight lesions in search of insect larvae, and it will be remarkable if they do not carry away blight spores upon their feathers, bill or feet. While the writer is not yet ready to make any positive statement in re- gard to the part which birds play in the spread of this pernicious disease of the chestnut, a pertinent fact may be mentioned. By the employment of careful analytic methods a single hairy wood- pecker has been found to be carrying as many as twenty different kinds of fungus spores. Johnson has suggested the possibility that the bud-rot of cocoanut may be carried by turkey buzzards as well as by certain insects and reports some experiments which seem to lend support to his contention.?°
In considering this subject observations on and experiments with saprophytic fungi may be mentioned. Voglino”? has shown that slugs eat the sporophores of fleshy agarics, especially the hymenium, and that the spores begin to germinate in their intes- tines and afterwards continue to grow in the ground in which the slugs burrow. The subterranean ascus-bearing tubers of truffles are sought as food by rodents and the spores of these fungi are sup- posed to be dispersed by this means.
Herbivorous animals play a very important part in the dis- persal of certain dung-inhabiting fungi. A considerable number of these dung inhabiting fungi expel their spores with considerable force from the fruiting body. If it were not for the grazing ani-
24 F. D. HEALD
mals these spores would in most cases, be carried no farther than the force of their projection would take them for they are sticky and adhere to the surface of the objects upon which they light. Foliage with attached spores is eaten by grazing animals and the spores being able to pass through the intestines of the animal un- harmed, find a suitable substratum for their development at some distant point. Among those forms which have developed this habit the following may be mentioned: Pleurage, Ascobolus and other black-knot allies which shoot their spores by the explosion of the ascus; and certain Hymenomycetes like Coprinus and allies.
DISSEMINATION BY AGRICULTURAL AND COMMERCIAL PRACTICES
Numerous instances of the transport of disease producing or- ganisms by man as a result of agricultural and commercial prac- tices are known. With the development of our agriculture and the intercourse between nations the part of man in the dissemina- tion of plant diseases has become more pronounced. The possi- bility of the spread of diseases and insect pests from one region to another has long been known and states have endeavored to safeguard the agricultural and horticultural interests of the people by laws relating to inspection of nursery and other stock. From the standpoint of fungus diseases this inspection has not been as effective as might be desired for in the majority of states the in- spectors have been entomologists, familiar only with the more evident plant diseases such as crown-gall or black-knot, and not skilled in the detection and diagnosis of the more obscure troubles. This statement is not imaginary but is based on facts, for the writer has, in numerous instances, visited nurseries immediately after the official inspection and found various fungus diseases prevalent that were entirely overlooked. The demand for nation- al legislation making restrictions which might govern the intro- duction of pests from foreign countries and the spread of troubles from infected regions to those free from the disease led to the recent passage of the Plant Quarantine Act.?®
Fungi which are primarily soil dwellers may be carried by transport of soil. Spores which have not yet germinated may be
DISSEMINATION OF FUNGI 25
incorporated with the soil but in some of the most serious troubles the fungus is present in the mycelial or in the sclerotial stage. One of the agricultural practices that should be condemned on this account is the use of alfalfa soil for the inoculation of a field with the nitrogen-fixing bacteria. If, for example, the soil selected contained the mycelium of the alfalfa Rhizoctonia or that of the southern fungus of cotton root rot, these troubles might be introduced into new fields. We have reason for believing that the sterile mycelium of such fungi will endure considerable dessica- tion without losing its vitality. The “spawn” of mushroom grow- ers is but mycelium preserved and temporarily dormant in dried bricks of compost. It is particularly in the cultivation of plants under glass that we find the introduction of fungi and other pests with the soil. The drop or Sclerotinia disease of lettuce is one that persists by the development of sclerotia that may remain in the soil.*° It seems to be true that root-knot of roses is frequently introduced into greenhouses by the selection of soil previously in- fected with eel-worms.
Some parasitic fungi are capable of passing one stage in their life history in the soil or in compost. This is especially true in the case of certain smuts, of which corn smut is a most notable example. It is a common practice on farms to feed corn fodder or stover to cattle and return the compost to the soil. The smut spores find in the compost especially favorable conditions for germination and also for the production of secondary sporidia in countless numbers by a process of budding. Compost originating from the use of smut-infected corn may thus contain billions of sporidia of smut that are returned to the soil of the corn field where they are ready to produce new infections. The work of cultivation and the movement of wagons and teams from one field to another may be responsible for the spread of disease producing organisms. It is undoubtedly true that the mycelium of the cotton root rot is extensively spread through the fields during the culti- vation of the crop. It is claimed by Massee that club root, or the finger and toe disease of cruciferous plants, may be spread by soil adhering to cart wheels, tools, shoes, etc. The practice of allow- ing diseased plants, fruits or other products to fall to the ground
26 F. D. HEALD
and remain there unmolested save for the work of nature’s scav- engers is a too common practice that favors the spread of disease.
The part which man has played and is playing today in the dissemination of plant diseases can not be overlooked. This is the inevitable result of our specialized agriculture and modern com- mercial practices, but the distribution of diseases by the importation of infected seed, nursery and horticultural stock, and the transport of various commodities, can and should be reduced to a minimum by the employment of all possible safeguards.
Many of our serious plant diseases have been brought to this country from Europe or other foreign countries, and we can point in turn to pests which have been transported from America to Europe and elsewhere. The influence of climatic and edaphic fac- tors upon the development of disease in epidemic form must be taken into consideration. It is by no means certain that a fungus pest which has proved serious in one country will prove equally serious in another, but the existence of serious diseases in a coun- try or region should be kept in mind, and importations of sus- ceptible stock made with extreme care.
Commercial concerns, state agricultural experiment stations and departments of agriculture, and the United States Department of Agriculture are all importing seeds and plants from foreign countries, in the endeavor to find plants valuable for the trade or better suited to the agriculture of the country. If we reflect upon the nature of seed-borne fungi it must at once be evident that this wholesale importation of seed is bound to be a prolific source of the spread of disease. It is undoubtedly true that the black-leg of cabbage previously referred to was brought to this country by infected seed® and that potato wart recently reported from New- foundland was introduced from England.*® These are illustra- tions of recent importations and it was the discovery of this latter disease in this country that gave one of the strong arguments for the passage of the recent Plant Quarantine Act.
The shipment of nursery stock is frequently responsible for the appearance of diseases in hitherto uninfected territory. In the greater percentage of even well managed nurseries plant diseases of various kinds may be found in profusion, the massing together of
DISSEMINATION OF FUNGI 27
individuals favoring their development, but the neglected nursery is literally a pest house of plant diseases. The Pennsylvania Chest- nut Tree Blight Commission has records of spot infections of blight that were traced to the planting of nursery stock that was diseased at the time of shipment. The diseases of nursery stock that are accompanied by easily recognized symptoms, may easily be guarded against by rigid inspection of all stock offered for shipment, and fumigation is a reasonable safeguard against the spread of many insect pests, but unfortunately some of the most serious diseases can be carried by stock which shows no indication whatever of its presence. One of the most striking examples of this is to be found in the case of the seedlings of white pine affected with the so-called blister rust.4t_ The fungus causing this trouble has a period of in- cubation in the bark of nearly a year before it causes the character- istic hypertrophies, and for this reason inspection at the time of importation is but an imperfect insurance against its introduction. In such extreme cases the quarantine of infected regions and the restrictions of shipment of stock that might carry the disease is entirely justifiable. Diseases like the black-knot, peach leaf curl, orange rust of raspberries and blackberries, and many others that produce a perennial mycelium in the host may easily be transported by infected nursery stock, while there are many opportunities for the transport of resistant spores on the surface of florists’ green- house stock or field-grown plants. Besides this, incipient infec- tions of various fungi may be present in either herbaceous or woody plants, and entirely escape detection at the time of shipment.
The transport of various commodities such as hay, grain, pack- ing material, fruits, vegetables, wood, lumber and any crude plant products must play a part in the spread of plant disease. With our diversified trade relations with foreign countries and the extensive trans-continental shipments of plant products from west to east and from south to north, opportunities for the transport of plant diseases over wide ranges of territory are greater than ever before in entire progress of our agriculture.
Zoology Building, Univ. of Pa.
Philadelphia, Pa.
28
12.
13.
14.
15.
F. D. HEALD
LITERATURE CITED
Butier, A. H. R. Research on fungi. 1-287, 19009. Longmans, Green & Co. FRANK, A. B.
Die Krankheiten der Pflanzen. 2:380-382. 1806. Berichte der
deutsche. Bot. Ges. 1:31. 1883. WHETzZEL, H. H.
Some diseases of beans. Bull. Cornell Agr. Exp. Sta. 239 :198-214. 1906. Bean anthracnose. Bull. Cornell Agr. Exp. Sta. 255 :217- 222. 10908.
Van Hook, J. M.
Blight and powdery mildew of peas. Bull. Ohio Agr. Exp. Sta.
173 :231-249. 1906. Barre, H. W. ;
Report of the botanist. Report S. Carolina Agr. Exp. Sta. 1910:
23-26. Manns, T. F.
Two recent important cabbage diseases of Ohio. Bull. Ohio Agr.
Exp. Sta. 228 :255-207. I09II. CHapMaNn, G. H.
Notes on the occurrence of fungous spores on onion seed. Report
Mass. Agr. Exp. Sta. 1909 :164-167. I9QIO0. HEALp, F. D.
Bunt or stinking smut of wheat. Press. Bull. Nebr. Agr. Exp. Sta.
28 :1-8: 1908. Bottey, H. L. The use of the centrifuge in diagnosing plant diseases. Proc. Soc. Prom. Agr. Sci. 1902 :82-85. StorRMER, K. and ErcH1ncer, A. Frithling’s Landw, Ztg. 50:303-413. I9gI0. Hatstep, B. D. and Farrcuitp, D, G. ~ Sweet potato black-rot. Journ. Myc. 7:1-11. 1801. Coons, G. H.
Some investigations of the cedar rust fungus. Ann. Report Nebr.
Agr. Exp. Sta. 25 :215-245. 1912. Wotr, F. A.
The prevalence of certain parasitic and saprophytic fungi in orch- ards as determined by plate cultures. Plant World 13:164-172% 190-202, IQIO.
Futton, H. R.
Recent notes on the chestnut bark disease. Penn. Chest. Blight Conference Rpt. 48-56. 1912.
Anperson, P. J., Erza, W. H. and Bascock, D. C.
Field studies on the dissemination and growth of the chestnut blight fungus. Bull. Penns. Chestnut Blight Commission. 3:I-, 1913.
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DISSEMINATION OF FUNGI 29
Luioyp, F. E. and Rineway, C. S. Bull. Ala. Agr. Dept. 39:1-I9. IQII. Burritt, J. T. and Barrett, T. J. The ear rots of corn. Bull. Illinois Agr. Exp. Sta. 133 :65-109. 1908. . SmitH, R. E. The brown rot of the lemon. Bull. Cal. Agr. Exp. Sta: 190:1-70. 1907. Rocers, C. S. The late blight of celery. Bull. Cal. Agr. Exp. Sta. 208 :83-115. Furiton, T. W. The dispersal of the spores of fungi by the agency of insects with special reference to the Phalloidei. Ann. Bot, 3 :1899-90. Weseser, H. J. Sooty mold of the orange and its treatment. Bull. Div. Veg. Phys. and Path. U. S. Dept. of Agr. 13:1-34. 1897. Waite, M. B. Cause and prevention of pear blight. Yearbook, U. S. Dept. Agr. 1895 :295-300. HEALp, F. D. The bud rot of carnations. Bull. Nebr. Agr. Exp. Sta. 103 :1-24. 1908. : Mourriti, W. A. A serious chestnut disease. Jour. N. Y. Bot. Garden. 7 :143-153. 1906. MasseEE, GEo. Diseases of cultivated plants and trees. 1-602. 1910. Macmillan & Co. Jounston, J. R. The history and cause of the cocoanut bud rot. Bull. Bur. Pl. Ind. 228 :1-175. I912. VocLino, P. Richerce intorno all’ azione delle lumache e dei rospi nello sviluppo di Agaricini. Nuovo Giornale Botanico 27 :181-185. 1895. Hays, W. M. Rules and regulations for carrying out the plant quarantine act. U. S. Dept. Agr. Cir. Office of Sec. 41:1-12. Ig12. Stevens, F. L. A serious lettuce disease. Bull. N. C. Agr. Exp. Sta. 217 :1-21. I91I. Gussow, H. T. A serious potato disease occurring in Newfoundland. Bull. Can. Cent. Exp. Farm. 63:1-8. 1900. SPAULDING, PERLEY. The blister rust of the white pine. Bull. Bur. of Pl. Ind. 206:1-88. IQII.
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THE PERIODICITY OF ALGAE IN ILLINOIS By Epcar NELson TRANSEAU
The following notes on the periodicity of algal occurrence and reproduction are based on a study of collections made at intervals, at more than a hundred stations in East-central Illinois. They cover the period from January, 1908, to January, 1913. About half of these stations are in the vicinity of Charleston. These have been visited at frequent intervals, while those at a distance have been examined at critical times of the year as suggested by conditions at Charleston.
All collections have been preserved in a solution, a liter of which contains 100 cc. formalin, 300 cc. alcohol, and 600 cc. of water. Each collection is labeled and numbered in the field and as soon as convenient a 4 by 6 inch index card is labeled and num- bered to correspond. On this is kept (1) a record of the weather conditions, water conditions, temperatures, relative abundance of algae in general, and whether floating or attached, etc.; (2) an analysis of the collection made in the laboratory, showing all algae present as far as identifiable. In the case of many only the genus can be given, together with measurements that might aid in de- termining them from later collections containing the same forms in a fruiting condition. In summarizing the work it is possible then to go back to cards or to the collections at any time and correct any errors or get any further data desired.
“The waters of Eastern Illinois are rich in dissolved mineral matters derived from the prairie soils. For example, the water of the Embarras river near Charleston contains on the average .14042g. of soluble matter per liter. It is consequently not surprising that the algal flora should be large and varied. Its extent may be roughly indicated by the fact that the collections contain more than forty- five species of Oedogonium, and the genus Spirogyra is represented by at least thirty-five species and varieties. These numbers are considerably more than have been reported from Massachusetts
32 E. N. TRANSEAU
whose algae are better known probably than those of any state in the Union.
In order to get at the periodicity the card records have been listed by months for the five-year period. An examination of the resulting chart shows that on the basis of their periods of greatest abundance, the duration of their vegetative cycles, and the times of their reproduction, the algae may be divided into seven classes.
I. Winter ANNuAtLS. These are species which begin their vegetative cycle in the autumn, increase up to the time the ponds are frozen, and last over the winter under the ice. During pro- tracted winter thaws—which usually occur in January—they may develop further and even fruit. Their period culminates in March and April. Sexual reproduction may occur at any time from No- vember to April. Zodspores are formed from the beginning through the period of increase. Aplanospores and akinetes develop mostly during the period of decline (Fig. 1). Some local examples of
NLL
Apr | May |June
Fig. 1. Frequency curve of winter annuals: In this and subsequent figures the probable occurrence of sexual reproduction is indicated by F, zoospore reproduction by Z, and the formation of aplanospores or akinetes by A.
algae belonging to this type are Vaucheria geminata, Vaucheria sessilis, Draparnaldia plumosa, Tetraspora lubrica, and Stigeoclo- nium lubricum varians.
II. Spring ANNUALS. These are forms in which the veg- etative period begins in late autumn or early spring, culminates in May and declines in June. Sexual reproduction occurs in April, May, and June. Zodspores are formed mostly in early spring, and
PERIODICITY IN ALGAE 33
aplanospores and akinetes during the period of maximum abundance and decline (Fig. 2). This type includes the largest number of
ie tae Se i eile
Fig. 2. Frequency curve of Spring Annuals
species, among which are Spirogyra varians, Spirogyra Weberi, Zygnema stellinum, Oedogonium rufescens, and Ulothrix variabilis.
Ill. Summer Annuats. The vegetative period of the algae of this class begins in early spring and culminates in July and August. The decline is gradual and extends through the autumn months. Sexual reproduction occurs in July, August and Sep- tember. Zodspores, when formed, are most abundant in Spring and early Summer. Aplanospores develop mostly in August and September (Fig. 3). Among the local examples of this class are
Fig. 3. Frequency curve of Summer Annuals
Spirogyra decimina, Spirogyra maxima, Schizomeris Leibleinii, Calothrix stagnalis, and Oedogonium V aucherit.
34 E. N. TRANSEAU
IV. Autumn Annuats. These species begin their vegetative development in late spring, increase through the summer and have their period of maximum abundance in the autumn. They may dis- appear at the time of freezing up of the ponds, or gradually through the winter. It has been noticed in at least one instance, Spirogyra setiformis, that when the freezing occured at the time of fruiting, a large part of the filaments still in a vegetative condition remained over the winter and completed the fruiting in the early spring. This is indicated in Fig. 4 by the dotted line. The sexual reproduction
Jan [Fes [ar Apr [may [Jane] July [Any [S000 [O08 [Pow [Dee
Fig. 4. Frequency curve of Autumn Annuals
usually occurs during September, October, and November. Among the algae of this class are Spirogyra nitida, Rivularia natans, Oedo- gonium crassum amplum, Spirogyra setiformis, and Oedogonium obtruncatum.
V. PERENNIALS. This group includes forms in which the vegetative cycle goes on from year to year without interruption. The algae may become very scarce during unfavorable periods but they are capable of at least maintaining themselves without the production of reproductive bodies. They commonly attain their greatest development during the summer and early autumn. Sex- ual organs are mostly produced in late spring or early autumn— sometimes in both. Zodspores are most abundant in spring and summer,—not infrequently they are also produced in autumn (Fig. 5). Cladophora glomerata, Rhizoclonium hieroglyphicum, Pitho- phora oedogonia, Pleurococcus vulgaris, and Ocdogontum grande belong to this class.
PERIODICITY IN ALGAE 35
eae 22 TPaaeeaneanata| all
Fig. 5. Frequency curve of Perennials
VI. Epuemerats. These species have very short vegetative cycles, usually best reckoned in days—at most in weeks. Genera- tions succeed one another rapidly through the periods of favorable conditions. Also because of varying capacities to respond to en- vironmental conditions the generations overlap. It is therefore difficult to represent this group by a curve or collection of curves. Figure 6 is an attempt to represent it in general. It must be re-
KN)
/
Rh " BPE aa Tine se Vinay | Jeselealy eg [end oes [oe neal
Fig. 6. Frequency curves of Ephemerals
SSS
membered that the lengths of the curve for a generation will vary in the different species and under different conditions of temper- ature, moisture and illumination. The species are mostly soil- surface and plankton forms. Few of them reproduce sexually. Zodspores, aplanospores and akinetes are the usual means of in- crease, dissemination and passing an unfavorable period. The soil
36 E. N. TRANSEAU
forms are favored by wet weather. All the forms may be found in greater or less abundance in all but the winter months. Among the commoner local Ephemerals are Botrydium Walrothii, Scenedes- mus quadricauda, Pediastrum Boryanum, Vaucheria terrestris, and Ine ffigiata neglecta.
VII. Irrecuvars. In addition to the above six types of per- iodicity there is a group of forms for which the combinations of environmental conditions necessary to induce marked vegetative development or bring about reproduction do not occur with seasonal regularity. The period between maxima may be of more or less than a year’s duration. Because of their uncertainty it is difficult to discover them in a five year collecting period. There is always the danger that they might have been overlooked during the first year or two when my collections were not so thoroughly repre- sentative as during the last three years. I will therefore venture but a single example: Oscillatoria princeps, for which I have a fairly satisfactory five-year record. This alga has been exceedingly abundant at times in one of the ponds from which I have collec- tions at short intervals. These periods of maximum development have occurred without seeming reference to season—aside from absence during the winter.
The diagrams for the several classes of periodicity show their own relative abundance during the different months of the year. The classes, however, do not represent equal parts of the algal vegetation of this region. In Fig. 7 I have attempted to show the relative importance of these several’classes. For reasons already stated the Irregulars are not included. One reason why the group of Spring Annuals is of such great importance is that the variety of habitats at this season is vastly greater than at any other period of the year. Habitat diversity and algal variety both have their minimum during late July and August. Fig. 7 also indicates the approximate composition of the algal flora at any time of the year. Thus in October the Perennials and Autumn Annuals constitute the bulk of the forms, with some remnants of the Summer Annuals, some Ephemerals, and some early stages of the Winter Annuals.
With regard to periodicity in general it must not be forgotten, that the classes observed in one locality do not necessarily occur in
PERIODICITY IN ALGAE 37
Jan €6 |Mar |Apr ay une ares Au ept reset Gens ov |Dec [Yan _| Fe Thay | J Stag Haase fee oe
Fig. 7. Estimated relative importance of the several types of algal periodicity, and the composition of the algal flora at any time of the year. This leaves out of ac- count the irregulars.
all others. Indeed, I have good reason to believe that farther north the number of classes is reduced and that two or more may be- come merged into one. Judging by the publications of Fritsch, in England many of the forms which occur here as winter annuals attain their maximum development there in the summer. Hence we may expect to find considerable local variations in the floristic composition of the periodicity classes.
There is a notion prevalent in the text books and laboratories that algae produce sex organs more abundantly during the low water stages. This is sometimes expressed by saying that we may look for sexually reproductive material when the water begins to con- centrate, or “when the conditions become hard enough,” whatever that may mean. Or it is said that they remain in a vegetative con- dition so long as the waters are high. That the opposite of this statement is true was strongly indicated by an examination of my records at the end of my first two years of collecting. In the three years that have since ensued I have watched this particular point with much care, and there can be no question that in this region at least (1) the greatest number of species fruit sexually, (2) a par- ticular species fruits most abundantly, and (3) when a species pro- duces more than one kind of spore, the greatest variety of spores
38 E. N. TRANSEAU
occur during periods of high water. The spring of 1912 was a period of heavy rainfall. The remnants of old prairie ponds along the railroad rights-of-way contained fruiting algae in quantity and variety beyond anything seen during the preceding four years. The high water-level was maintained until after the spores were mature. On examining the corresponding collections for the spring of 1911 I find what are probably the vegetative filaments of many of these same forms, but only a few produced spores. Again, the autumn of 1911 was one of exceedingly high water,—the rainfall of Sep- tember being more than three times normal. Coincidently a num- ber of species which I had before found fruiting only in the spring, developed and fruited before the pools froze. These algae fruited again in the spring in some of the same pools. Whether the fila- ments developed from the spores of the preceding autumn, or from spring spores which failed to germinate in the autumn it is impos- sible to say. But the fact of importance is that the continued high water of the autumn of 1911 was attended by increased fruiting of algae.
The origin of the prevailing notion that algae fruit during low water stages may be connected with the fact that such a large num- ber of algae fruit in late spring when the rainfall is decreasing and the water levels are lowering. This is a coincidence of the lower- ing water level with the time of fruiting and there is no causal re- lation between the two. If the weather conditions are such that the water level does not fall at this time of year, but remains con- stant or rises the fruiting will not only take place but its amount will be increased.
Fig. 8 shows the number of species known to have fruited ei- ther sexually or asexually during each month for the years 1911 and 1912. The years are also divided into seasons and the total num- ber of monthly records per season is indicated in the second line from the bottom. In the last line is given the water level, as shown by Weather Bureau records of rainfall, and my own notes. It should further be noted that the seasons during these two years are exactly opposite in so far as rainfall and water levels are concerned. Leaving out of account the temperature conditions which at most are of secondary importance, we have here a basis for direct com-
——————
PERIODICITY IN ALGAE 39
fet tS | SPS
olen RES sles ol at
hoa 44 ae ee Pie wae mas eee
Fig. 8. Number of monthly fruiting records (both sexual and asexual) grouped by seasons and compared with the water level. It will be noted that for each of the seasons the conditions were opposite in these two years. Note correlation between high water level and increased fruiting.
parison of wet and dry seasons. The close correlation between high water level and increased fruiting is too obvious to need further comment. The only record which shows a marked temperature in- fluence is the one for the winter of 1912. There was not the usual thaw in January and February, which would bring this number near- er the winter mean.
Another notion prevails that sexual reproduction is confined to the time of maximum vegetative development. While it is prob- ably true of a majority of algae, I wish to call attention to the fact that there are many exceptions. When a more detailed report of these collections can be made, there is reason to believe a list of con- siderable length will show that many algae may reproduce sexually at any or all stages of their vegetative cycle. In other words vege- tative development may follow sexual reproduction or may go along with it, as well as precede it.
The failure of algae to fruit in streams has been mentioned by numerous authors. Klebs and Oltmanns speak of the Vaucherias, and Fritsch speaks of the Spirogyras. For eastern Illinois I can record the fact that all the species of Vaucheria, Spirogyra and Oedogonium known to grow in our streams have been collected at
40 E. N. TRANSEAU
one time or another in fruit. I do not, however, doubt the accuracy of the European observations. Our streams possibly are more slug- gish and perhaps there is a chemical difference of importance. The flowing water is generally supposed to retard fruiting by furnish- ing improved vegetative conditions. Hence we should expect a re- tarding effect on fruiting which would show clearly in the relative time of fruiting in ponds and streams. On going over the records for species which have been collected in fruit in both situations | find that the stream record is likely to be simultaneous with, or pre- cede, or follow the pond record. As far as I have studied the records there is no evidence of a retarding effect of running water. There is abundant evidence to show that the number of possible combinations of external factors that will produce sexual re- production is very much less than the number that will induce zooOspore production. Zodspores may be formed at short intervals throughout the life cycle while the sex organs usually develop at a definite time. The formation of non-motile spores in Pithophora seemingly occurs under any and all conditions. This represents the one extreme. At the other is Zygnema pectinatum which produced aplanospores but once in the five years and then they were common wherever the Zygnema was found.
It seemed best to the writer to await the completion of the ex- amination of the collections before attempting to discuss the litera- ture and the details connected with this problem of periodicity. The names of the green algae used in this paper correspond to those found in Collins’ “Green Algae of North America.”
Eastern Illinois Normal School,
Charleston, II.
>) es
SUMMARIES IN MICRO-BIOLOGY
For some months the Secretary has been planning to secure for this Journal and its Department of Summaries, a series of papers from biologists dealing with the chief groups of microscopic plants and animals. It has not been the purpose to present a complete survey of any of the groups. The wish has been rather to bring together in one article a statement of the following things:—general biology, the method of finding, the methods of capture and of keeping alive and cultivating in the laboratory; how best to study; the general technic; the most accessible literature; and a brief outline of the classification, with keys for the identification of at least the more representative genera and species of the micro-organisms likely to be found by the beginning students in the United States.
It has been felt that the getting together of such data as this, while not a contribution to science, would be a contribution especially to isolated workers and to teachers and stu- dents in the high schools and smaller colleges.
Papers have already appeared treating the aquatic Oligochetes and the Melan- coniales. The following is the third paper of the series. It is proposed to have such synopses from time to time until the more common American species of such groups as the following have been covered: The Blue-green Algae, Conjugating Algae, Diatoms, other Green Algae, Zygomycetes, Downy Mildews, Yeasts, Powdery Mildews, Hypho- mycetes, Smuts, Rhizopods, Infusoria, Turbeliaria, Bryozoa, Water Mites, Entomostraca, etc.—[ Editor. ]
THE NATURE AND CLASSIFICATION OF PLANT RUSTS By Frank D. Kern
1. Introduction.
The rusts are small, mostly microscopic fungi, parasitic in the tissues, especially the leaves, of the higher plants. They belong to the order Uredinales (or Uredineae) which contains without doubt the largest array of forms of any order of parasitic fungi. There is an extensive economic interest in the rusts because of the fact that they do great damage to most of the cultivated crops. Their varied spore-formation makes them at once of unusual interest to the general student with the microscope. Many species have spores of five morphological sorts. In some species these occur in regular succession upon one sort of host-plant but in many there is a strik- ing change of hosts (known as heteroecism), a definite part of the life-cycle being produced quite apart and dissociated from the other part.
The spores are borne in more or less definite groups called sori (rarely singly), covered at least at first by overlying host tissue and set free either by early rupture or by weathering. On account of the fact that the mycelium is always wholly buried within the host
42 F. D. KERN
tissues it is quite natural to fall into the habit of thinking and speak- ing of the spore-structures, which manifest themselves upon the surface, as if they constituted the whole plant instead of representing only the reproductive portions. Although it is true that this treat- ment will confine itself chiefly to the spore-structures yet it is well to get the conception at the start that we must look upon the mycelium with its resulting spore-forms, in its entirety, if we would compare these little organisms with other and higher plants.
On account of the vast array of these forms, many of which have never been investigated by anyone, it is manifestly impossible to present much in the way of description of specific forms. It is hoped, however, that a.statement of the main features of morphology and life-history together with their application to classification may serve to break down some of the apprehensive feelings which many now entertain toward the group as a whole. It is with this object in view that the following discussion is presented. The systematic account is confined to genera and species found in the United States.
2. Habitat and Distribution.
The rusts are strictly parasitic upon ferns and flowering plants and are liable to be found anywhere upon these hosts. Although the spores are microscopic in size, when aggregated into sori they are often conspicuous even to the naked eye and can usually be recog- nized easily under a hand lens. The sori may appear upon any part of the host above ground but the leaves are most commonly affected. Presence of rust may often be indicated by yellow or discolored spots upon the leaf-blades, or by swellings and galls upon the petioles and stems, or by fasciations of the branches known as witches’ brooms.
In consistency the sori may be powdery (pulverulent), from the falling away of the spores, or they may be compact and firm, or in some species gelatinous. In shape and size there is great variation. Often they are roundish or oval, about 0.2-1 mm. across and more or less cushion-shaped (pulvinate); some are cup-shaped (cupu- late), 0.1-0.4 mm. in diameter ; others project as cylindrical, filiform, columnar, or wedge-shaped masses varying in length from 2 or 3 mm. up to 10 or 20 mm. In practically all cases the spore-mass is elevated to some extent above the surface of the host tissue and by
EEE eee
PLANT RUSTS 43
this means alone it is often possible to distinguish in the field be- tween true rusts and many spot-fungi which simulate rusts in gen- eral appearance. This is especially true of grass and sedge rusts. In color the various shades of yellow and brown predominate, but some are so pale as to appear almost white, while many are dark enough to be called black.
Rusts attack plants in all sorts of physical and climatic condi- tions from the seashore to the summits of the highest mountains, and from the tropics to the polar regions. There is scarcely a family? of flowering plants in which some of the members are not affected by these parasites. In most any region where there is vege- tation some rusts can be found. In the fields on wheat, oats, and other cereals; in the orchards on apples, pears, and quinces; in the gardens on asparagus and beans; in the ornamental plantings on roses, hawthorns, and cedars; in greenhouses on carnations and chrysanthemums ; in the forest on pines, spruces, firs, oaks, cotton- woods, and willows; in low places and swamps on sedges and crow- foots ; in semi-arid regions on sage-brush and greasewood; in wild and waste places everywhere on grasses, sunflowers, asters, golden- rods, dandelions, and hundreds of other weeds and flowers.
Because a rust is known to live upon a certain host it does not necessarily follow that the rust can be found wherever the host grows. Wild roses have several species known on them; one of these is found practically everywhere throughout the region of the hosts, while the others seem restricted to certain geographic loca- tions, for example one is in the northeastern states, another in the prairie region of the central west, another in the Rocky Mountains and so on. Some rusts which change hosts, as indicated in a fore- going paragraph, might be expected to be limited to the region which is common to both hosts, but the fact that many of these have the capacity to maintain themselves independently on one host upsets this expectancy. A notable illustration of this is the common stem- rust of wheat which can have one stage on the barberry if any bushes are in proximity but which flourishes equally well in regions where the barberry is unknown.
1. The order Pandanales, of which the cat-tail (Typha) is our representative, and
the Palmales, the palms, are conspicuous examples of large alliances upon which no Tusts are known.
44 F. D, KERN
It becomes evident from the foregoing discussion that in a study of these fungi a study of the hosts is also not only important but necessary. A knowledge of the hosts is essential in classification and identification. A good way to begin is to examine and become familiar with all of the forms of rust on some particular host or closely related groups of hosts. In that way an interesting know- ledge of flowering plants will be built up as the study proceeds from one group to another.
3. Collecting.
In collecting one keeps the eye on practically all of the vege- tation, looking especially for discolored spots and swollen (hyper- trophied) areas but does not fail to take hold of and examine closely many a plant which appears perfectly normal. A leaf or shoot which is more upright than usual is always suspicious. A hand lens is very useful and may assist greatly in forming a judgment as to whether a rust is present. Until one becomes familiar with the gross appearances of the various sori it is well to take home ques- tionable material for microscopic examination.
It is always best to gather a fair amount of material. The im- portance of gathering sufficient to give some clue as to the identity of the host after the specimen has been preserved and packeted can- not be over emphasized. Flowers or some portion of the infloresence should be included whenever available, portions of the stem, un- rusted leaves, basal leaves, etc., are advantageous. Care should al- ways be taken to make sure that the rusted specimens and the por- tions included for host identification are from the same plant, or species, otherwise some very curious results may be obtained. Such a warning may seem unnecessary but such things have happened to experienced collectors. Some make it a point to gather separate phanerogamic specimens for the host determination but such is not necessary as a rule and is less convenient than the inclusion of smaller diagnostic port‘ons of the host to be included with the fun- gous specimens.
4. Care and Cultivation.
If specimens are desired for future study only they do not require any special treatment but are best preserved by pressing
PLANT RUSTS 45
them in the ordinary method between some sort of absorbent driers. If it is desired to keep the spores alive so that they may be germi- nated and studied, or used for inoculating purposes, then certain precautions are necessary.
In general we may divide the spores into two classes, active and resting. The active class includes the cluster-cup spores, the summer or red-rust spores, and certain others such as those of the common cedar-apples. These spores are ready for germination upon maturity and will lose the power to grow unless kept in a reas- onably fresh condition. If it is desired to keep them alive the parts of the host upon which they are growing should be kept as near normal as possible. In the case of small herbaceous plants often the best way is to remove them to pots, taking care to transfer a sufficient ball of earth so that the shock of transplanting will be reduced to a minimum. Oftentimes portions of the host-plant may be kept fresh for a sufficient time by placing the cut ends of stems or branches in water.
The winter or so-called black-rust condition of grass and sedge rusts furnish fine examples of the resting class of spores. These spores are produced in the late summer or fall and normally re- tain their viability through the winter and germinate in the spring. Collections made in the fall and kept in a warm dry room during the winter usually fail to germinate. The freezing temperature of the outdoor atmosphere is not detrimental. It is necessary to pre- vent the specimens from thoroughly drying. If put up in cheese cloth packets and tied to the branches of a shrub close to the ground the spores will usually winter over well. Resting spores collected in the field in the early spring usually show good germination. In the spring the cloth packets should be brought into the laboratory about the time conditions are favorable for growth outside. The packets may be sprayed and after a few days of warmth and mois- ture the spores should show signs of growth.
Germination can be nicely observed in a hanging drop culture. Ordinary tap water is used for the hanging drop. If care is taken to make the drop rather shallow it will be possible to focus with the ordinary high power. The time required for germination de- pends upon the conditions in which the material has been kept. The
46 F. D, KERN
germ-tubes may begin to show up in an hour or two. A drop cul- ture which does not show germination in twenty-four hours may as well be discarded.
If it is desired to make an inoculation indoors some small vig- orous potted plants must be available. In case it is desired to carry out such an experiment indoors for demonstration purposes it is necessary to know the species with which one is dealing in order to attempt the inoculation upon the right species of host or else the re- sults would be very uncertain. For example there are about one hundred species of rusts on grasses in North America. It is certain that they all produce cluster cup stages on various broad-leaved plants, but the life-histories of more than half of them are still un- known. If one is conducting an investigation many trial inocula- tions are attempted and some of them occasionally meet with suc- cess, but for demonstration one must select forms which can be expected to produce success. A few suggestions may not be out of place here.
The black-rust spores from the stems of wheat will infect the leaves of the barberry (Berberis). Young barberries may be grown in pots from seeds. The grayish-black rust from the leaves of oats will inoculate the buckthorn (Rhamnus), which may also be grown easily from seeds. The sunflower rust does not change hosts and the spores from the dark brown sori on wintered over leaves may be transferred to young sunflower plants and will produce there the cluster-cup stage. Spores from the common large cedar-apple on the red cedar will produce abundant infection on the wild crab- apple or the cultivated apple.
For indoor experiments the spores are removed from the grasses with a knife or scapel blade and applied to the moistened leaves of the trial host. In the case of the cedar rust it is not neces- sary to apply the spores but merely to suspend the cedar-apple over the plant. A moist surface and a saturated atmosphere are neces- sary factors for the germination of the spores. In order to insure these conditions the plant is sprayed with an atomizer before the spores are sown, the parts which will not dampen being rubbed with the fingers until water will adhere. After the sowing is made the plant is placed under a bell-jar and set in a shaded position for
PLANT RUSTS 47
two or three days. The bell-jar is temporarily removed each day to permit a change of air and is sprayed on the inside with an ato- mizer before being replaced.
After an inoculation is made an incubation period of about a week or ten days will elapse before infection will be evident by the appearance of sori on the areas where the spores were sown. This period must be taken into account if a teacher desires to have a demonstration ready at some given time.
5. Methods for Study.
The spores of practically all species of rust make excellent ob- jects for microscopic study by simply mounting them in a drop of water on a slide and adding a cover glass, without any treatment whatsoever. It makes little difference whether the spores are fresh or whether they are from dried specimens they will as a rule make a good mount in water. It is even possible to allow a slide to dry out and then to run water under the cover glass and secure very good results. Distilled water is preferable to tap water.
Sometimes when spores are quite old and dry they do not wet up easily or appear somewhat shrunken. A good treatment in such cases is the addition of a little lactic acid to the drop of water. This will cause the spores to round out and take on a normal rotund appearance without producing any appreciable swelling.
On account of the ease and satisfaction in making spore mounts as described in the foregoing paragraphs it is rare that there is any occasion for attempting permanent mounts of spores. For purposes of studying the structure of the sori it is often desirable to have sections and very beautiful results can be obtained by fixing fresh material, embedding in paraffin and proceeding in the ordinary way, no special precautions being necessary. It is possible, however, to secure good preparations without resorting to the cytological methods. With some practice many will find it possible to cut good free-hand sections in pith. If the specimens are dry a small portion containing the sori is soaked in very hot water—if the water comes to a boil it will do no harm. Pith soaked in alcohol is preferable to dry pith. The pith cylinder is partially split to allow the insertion of the material and then, with some water on the razor blade to float the sections, all is in readiness. The sections can be removed
48 F. D. KERN
with a needle or sharp wooden pick to a slide and are ready at once for microscopic examination.
6. Characters that may be used in distinguishing the species.
In the classification and identification of the rusts there are three features which are of importance (1) the microscopic char- acter of the spores and sori, (2) the life-cycle, i. e. the number of stages in development, so far as it can be made out, and (3) the name and systematic position of the host. The first can be learned from the microscope; the second cannot always be. made out, but after a little practice helpful inferences may often be drawn; while the third must depend upon the familiarity with the flowering plants, the ability to work them out, or to secure competent aid.
AAHNOLO
a b NI oe Sat Cc d Fig. 1. A teliospore in process of Fig. 2. Different types of free, stalked
germination. Two of the lower cells have teliospores: (a) 1-celled, the wall smooth
young promycelia, the uppermost cell has (Nigredo Polemonii); (b) 2-celled, the wall
a well advanced promycelium. This one smooth (Dicaeoma Grossulariae); (c) 3-
shows the division into four basidia, three ceed by oblique septa, the wall spinous;
of which are shown forming basidiospores. (d) several-celled by transverse septa, the wall verrucose, the pedicel swollen (Phrag- midium subcorticinum).
The rusts usually have more than one spore stage, the differ-
PLANT RUSTS 49
ent stages or phases appearing in a definite sequence and collective- ly referred to as the life-cycle or life-history. Of the five morpho- logical sorts of spores mentioned in a foregoing paragraph only four are borne in sori on the host, the fifth being of a secondary nature produced upon the germination of one of the other forms (see Fig. 1). This fifth sort, known as a basidiospore because it is produced on a basidium, is important in indicating the relationship of the rusts to other fungi but is of no importance in identfication. The basidia themselves are of importance, especially as regards their formation whether within or without the spore.
Of the four sorts of spores borne in sori only one is common to all species, this one (together with the basidiospores) compris- ing the full life-cycle in some species. This stage which is never lacking in any life-history is known as the teliwm (plural telia) and the spores as teliospores, sometimes called also teleutospores, and represented by the symbol III. The teliospores may be 1-several- celled (see Fig. 2), the wall may be smooth or rough but is not in any known species set with prickles (echinulate). Upon germina- tion the teliospores produce the secondary basidiospores, which upon successful infection usually produce the pycnial stage, the sori being known as pycnia or often as spermogonia. The pycnio- spores are functionless so far as known and do not produce in- fections, but the presence of this stage is often of value in de- termining a life-cycle. Depending upon the life-cycle the rusts
Fig. 3. A vertical section through a portion of telium which shows a single layer of spores compacted laterally. The sorus is subepidermal and the flattened epidermis is shown extending over the spores. The species represented is Melampsora Medusae on Salix. may be divided into two groups, one with a short cycle and the other with a long cycle. In the short-cycle forms the mycelium from a basidiospore produces pycnia which are followed at once by telio- spores or sometimes there is a suppression of the pycnia. The
50 F. D. KERN
pycnia usually appear as honey-yellow specks at first, often becom- ing blackish with age. The stage is often designated by the symbol O.
The long-cycle forms have the pycnia and telia and in addition have between the two either aecia or uredinia or both produced, in the order named. These two additional stages form important parts of the life-cycle.
The aecial stage is the so-called cluster-cup stage, deriving that name from the fact that each aecium, or aecidium, is in many species provided with a covering (peridium) which later opens out into a cup-like receptacle enclosing a mass of spores. The edge of this peridium often becomes toothed or fringed. In some forms the peridium becomes long and cylindrical while in others it is entirely lacking. Sometimes the aecia are encircled by clavate or capitate structures known as paraphyses (see Fig. 4, b). The aeciospores are usually borne in chains, are always 1-celled, the wall is rough- ened with more or less evident roundish warts (verrucose), and is in many species colorless. The symbol for the stage is I.
a b
Fig. 4. (a) Showing the surface sculp- turing on the side wall (longitudinal radial) of a peridial cell of Gymnosporangium globosum. The different species differ in the character of the markings. When in place in the peridial tissue other cells are
a b
joined end to end and side by side. (b) Showing the general nature of a paraphysis. These structures surround the spore groups in some species and in others may be inter- mixed with the spores.
Fig. 5. Two types of urediniospores: (a) an ellipsoid spore with echinulate walls and four equatorial germ-pores (Dicaeoma poculiforme); (b) a globoid spore with ver- rucose walls and six scattered pores.
The uredinial stage is the one often popularly referred to as
the red rust stage.
In most genera the wrediniospores (see Fig 5),
or uredospores, are borne singly on pedicels in naked sori, but in some they are in chains and may be surrounded by peridia or by
paraphyses.
The walls of the spores are usually colored and are
PLANT RUSTS 51
always rough, either echinulate or verrucose. The spores afe single-celled. Functionally these spores are repeating spores, i. e. they may reproduce themselves over and over indefinitely. The symbol for this stage is II.
The microscopic spore-characters most used are shape and size, surface markings, color and thickness of walls. In the case of teliospores the number of cells is important as is also the shape, size, and color of the pedicel which often remains attached. With regard to the urediniospores the number and location of the germ-pores are often of great value. These pores appear as lighter circular areas about I-1.54 in diameter and as they are the places through which the germ-tubes penetrate they are called germ-pores. The lactic acid treatment will usually assist in bringing them out more clearly than water alone. In some groups the characters of the peridial cells must be observed, especially the surface markings (see Fig. 4,a). The fine and varied character of the surface sculp- turing on some of these cells almost makes them rank with diatoms as objects of microscopic interest.
7. Topics for Investigation Suitable to the General Student of the Group.
The rusts form an interesting group in which much remains to be done in the United States. One of the most fascinating and at the same time profitable opportunities for botanical students everywhere is to institute a careful study of heteroecious forms. Heteroecious species are divided into two wholly unlike halves and actual culture (inoculation) experiments are necessary to prove a relationship. In order that the work of connecting the halves may go on expeditiously, with as little unprofitable labor as possible, it is essential that the experimenter be guided by some ideas of probable relationships. These ideas can be gained in the field. The finding of aecial and telial stages in close proximity in the field is, to be sure, not proof of their affinity but is a bit of prima facie evidence. The closeness of the association, the abundance of the infection, and the occurrence of known forms must all be taken into account. Observations can best be begun in the early spring when new growth is starting. To find a tuft of grass or sedge cov- ered with wintered over teliospores in contact with some new shoots
52 F. D, KERN
of a broad leaved plant bearing aecia is a strong suggestion of genetic relationship. Since in North America there are about one hundred aecial forms whose relations to telial forms are unknown it will be recognized that there is abundant opportunity for field observations. The problem may be stated from the other view- point by saying that there are scores of telial forms whose rela- tions to aecia must exist but are unknown.
Some observers without greenhouse facilities may like to verify their clues by means of actual cultures. It is often possible to obtain very satisfactory results by means of outdoor cultures in a garden or other protected place. Much valuable work has been done in this way. For example, plants known to bear aecia can be _ transplanted to the garden and cared for until they establish them- selves. During the winter rust on grass suspected of being related can be placed over the ground so that the young shoots will have to push up through it. In this way results may be obtained early before the danger of stray infections is so great. If more than one such experiment is tried in the same garden much care must be observed to prevent cross infections which might lead to confusion.
8. Systematic (General).
Teliospores compacted laterally into flattened, cushion-like masses (see Fig. 3), or filiform, columnar masses (rarely solitary within the tissues), without stalks.
Walls of teliospores gelatinous, especially at apex, dividing internally into four basidia. Family 1. Coleosporiaceae. Walls of teliospores firm, without internal division of con- tents. Family 2. Uredinaceae.
Teliospores free (see Fig. 2) or united in bundles, stalked, the walls firm, or with an outer hygroscopic layer.
Family 3. Aecidiaceae.
Some authors include the first two families in one under the
name Melampsoraceae, and use the name Pucciniaceae for the third instead of Aecidiaceae as given above.
9. Systematic (Special). FAMILY 1. COLEOSPORIACEAE This family contains only one genus of importance, Coleospor-
PLANT RUSTS 53
ium, with about 24 species. The genus has all four spore-stages. All the species are heteroecious, the aecia being the blister rusts on the leaves (not on the twigs or bark) of pine trees (Pinus). The uredinia are yellowish and powdery; the telia form waxy cushions ; the teliospores germinate upon maturity in the fall and the in- ternal division of the contents into four basidia can generally be observed with the microscope without difficulty. The following common species may be mentioned.
Coleosporium Ipomoae (Schw.) Burr. on Ipomoea, urediniospores with uniformly thin wall 1-1;54; C. Campanulae (Pers.) Lev. on Campanula, urediniospores with uniformly thick wall, 2-3.54; C. Vernoniae B. & C. on Vernonia, urediniospores with wall 1-2 at sides, often 2-5u above; C. Soli- daginis (Schw.) Thiim. on Aster, Euthamia, and Solidago, urediniospores with uniform wall, about 1-2u. The urediniospores of the different species do not vary much in size, averaging 14-22x20-30n.
FAMILY 2. UREDINACEAE
This family is represented in North America by seventeen or eighteen genera and a considerable number of species. In the United States only seven of these genera are common, the others being chiefly from tropical regions.
Key To THE PRINCIPAL GENERA Teliospores in definite and limited sori, usually on the leaf-blades; uredi- niospores rounded.
Telia conspicuous, raising or breaking through the epidermis, telio-
spores I-celled. Telia in the form of cushion-like masses; urediniospore-wall
verrucose. Teliospores in a single layer; urediniospores with inter- mixed .pataphiyses. gosh dk. dias: Genus Melampsora Teliospores in chains; uredinia with a delicate peridium or ‘naked. . 0s wsaverses dees testes Genus Melampsoropsis Telia extruding as long filiform columns; urediniospore-wall echintlate. : 25.2252. :20 heen aeeees as Genus Cronartium
Telia inconspicuous, in a layer in the epidermal cells or just below them, teliospores 2-4-celled.
Teliospore-wall brownish; uredinial peridium opening with a definite orifice surrounded by longer cells, urediniospores eehtuilate 204 5:5 /ssd Je seae taken seme Genus Pucciniastrum
Teliospore-wall colorless; uredinial peridium without definite orifice, the cells longer at the sides and shorter toward apex, urediniospores verrucose................ Genus Hyalopsora
54 F. D. KERN
Teliospores solitary, or in very loose groups, usually buried within the
parenchymal tissues; urediniospores pointed.......... Genus Uredinopsis Teliospores forming continuous layers around elongated and thickened stems, not erumpent; uredinial stage lacking............... Genus Calyptospora
GENUS MELAMPSORA CAST.
A prior name for this genus is Uredo. But as that word has been in general use as the name of a stage, the one called in this paper the uredinial stage, and its restriction to a true generic application might lead to confusion, a later and more commonly used name is here maintained.
The genus contains both heteroecious and autoecious species. The aecia have no peridium.?. A conspicuous feature of the uredinia are the numerous, large paraphyses. Both aeciospores and uredinio- spores have colorless, verrucose walls. There are three common species.
Species
M. Medusae Thiim. Urediniospores smooth on two sides which are thickened, I on Larix, II and III on Populus.
M. Bigelowii Thiim. Urediniospores with walls evenly thick and evenly verrucose, I also on Larix, very similar to the preceding, II and III on Salix (see Fig. 3).
M. Lint (Schum.) Desm. Autoecious, on Linum.
Genus MELAMpsoropsis (SCHROT.) ARTH. (Sometimes included in CHRYSOMYXA).
Found in its uredinial and telial stages only on the order Ericales. The aecia so far as known occur on the leaves or cones of spruces (Picea). Several of the species are rather rare. M. Pyrolea (DC.) Arth. on wintergreen (Pyrola) is common. There are two species on Labrador tea (Ledum) ; M. ledicola (Peck) Arth. with the II and III on the upper side of the leaves, urediniospores moderately large, 18-29 x26-36p, wall 2.5-3n thick; and WM. abietina (A. & S.) Arth. with sori on the under surfaces of the leaves, ure- diniospores moderately small, 14-22 x20-30p, wall 1.5-2.5 thick. A uredinial stage on Cassandra calyculata, which is very rarely ac- companied by telia, is M. Cassandrae (P. & C.) Arth.
GENuS CRONARTIUM FRIES. A very striking genus in the telial stage on account of the long (0.5-3 mm.) filiform spore-columns. Cultures have proven that
2. The term caeoma is often applied to such forms, i. e. to aecia in which the peridium is lacking.
ee
—
. } :
PLANT RUSTS 55
the aecial stages are the blister rusts of the twigs, branches and trunks of pines (Pinus). Species
C. Comptoniae Arth. A common form along the north At- lantic coast on the sweet gale (Myrica Gale) and sweet fern (M. asplenifolia).
C. Quercuus (Brond.) Schrot. is widely distributed on various species of oak (Quercus). The aecial stage (called Peridermium cerebrum Peck) on pines forms globoid swellings of the branches upon which the orange-yellow aecia are arranged in a cerebroid fashion.
C. ribicola Fisch. de Waldh. is a rather recent importation from Europe and is a very serious disease of white pine (Pinus strobus) seedlings. The telial stage on Ribes (currants) is also appearing in this country.
GENUS PUCCINIASTRUM OTTH.
The characteristic feature of this genus is the hemispherical or subconical peridium of the uredinial stages with a pore-like orifice at apex surrounded by elongated cells, which are often echinulate above. Owing to the fact that the telia remain covered (indehiscent) they are somewhat difficult to study, and the parti- tions of the teliospores being vertical are not readily made out. Of the nine or ten species the following are the more common ones, others may be found upon Hydrangea, Rubus, Arctostaphylos, and Vaccimum.
Species
P. Agrimomiae (Schw.) Tranz. Common on Agrimonia from New England to North Dakota southward to Florida and Mexico.
P. pustulatum (Pers.) Diet. Widely distributed, especially northward on various species of Epilobium.
P. Pyrolae (Pers.) Diet. on Pyrola and Chimaphila, can be dis- tinguished from the Melampsoropsis on Pyrola by the nature of the uredinial peridium and the echinulate markings of the uredinio- spores.
GENERA Hyatopsora Maen. and UREDINIopsis Macn.
These genera include all of the rusts which are known on ferns in America. The cycle of development in both genera is not well understood. Both have two spore-forms
56 F. D. KERN
.
known on the fern-hosts aside from the telia. Some authors have looked upon one of these forms as aecia and the other as uredinia but evidence is lacking to prove the correctness of this assumption and recent work® indicating the heteroecious character of certain species of Uredinopsis throws some doubt upon that disposition. For the most part the two genera occur upon different genera of ferns; Hyalopsora on Phegopteris, Cystopteris, Polypodium, and Pellaea; Uredinopsis on Osmunda, Onoclea, Pteridium, Asplenium, and Dryopteris. The two genera can be further separated by the fact that one of the spore-forms of Uredinopsis has fusiform spores which are acute or beaked above, with a wall which is smooth except for two longitudinal ridges bearing single rows of minute projections, while both spore-forms in Hyalopsora have rounded spores with evenly verrucose walls. H. Aspidiotus (Peck) Magn. is the most widely distributed of the four species belonging to that genus; U. Osmundae Magn. on Osmunda, U. mirabilis (Peck) Magn. on Onoclea, and U. Atkinsonii Magn. on Asplenium and Dryop- teris are the best known of the seven described species of Uredinopsis.
GENus CALytTosporA Kuhn.
Only one species is at present recognized in this genus, C. columnaris (A. & S.) Kuhn (C. Goeppertiana Kiithn). Uredinia are lacking; the telia are found on Vaccinium, and the aecia on the balsam fir (Abies balsameum) in this.country. The telia form an even, polished, reddish-brown layer around the elongated and enlarged stems; the teliospores are closely packed in the epidermal cells, the wall of each spore very thin at the sides 0.5-0.8u, some- what thicker above I-I.5y.
FAMILY 3. AECIDIACEAE (Called also PUCCINIACEAE)
In this family belong the largest number of rusts, including for the most part those that cause serious injury to economic plants. The number of genera to be dealt with is dependent upon the scheme of classification which one follows. According to the old method any species of the group having free teliospores would be- long to the genus Puccinia if it possessed a single other character, i. e. two-celled teliospores (see Fig. 2, b). Likewise those forms would belong to Uromyces, which possess one-celled teliospores (see Fig. 2,a). Such a scheme, based on only one character, brought together, as a genus, species of the most diverse forms and varied affinities. A classification which takes into consideration the nature of the spore-wall, germ-pores, the origin of the sorus, i. e. whether under the cuticle or under the epidermis, the life-cycle, whether one or more stages are lacking, and other important characters will, of course, segregate the species usually placed under Puccinia
3. Fraser, W. P. Science, N.S. 36:595. 1912.
PLANT RUSTS 57
and Uromyces and increase the number of genera, but it will have the very great advantage of forming groups which have some affinities. Following such a system we have among the more com- mon forms in the United States about twelve genera to consider in the place of two, but this number might be decreased nearly one-half by not recognizing the purely artificial character of num- ber of cells as a basis for generic separation. The present state of knowledge does not seem sufficient, however, to warrant such a change. Key To THE PrINcIPAL GENERA Teliospores or pedicels, or both, more or less united; uredinia when present naked but often with intermixed paraphyses. Teliospores united into a head, or cushion-like body, on a compound
PECL O I eas SSete Sate ito Pe roe ea eS Ur ate Howto a as Genus Ravenelia Teliospores free but borne in groups of two to eight on a common stalk. Life-cycle with all spore-forms.............. Genus Tranzschelia Life-cycle with pycnia and telia................ Genus Polythelis
Teliospores and pedicels both free; uredinia when present without peridium but sometimes with encircling paraphyses.
Teliospores becoming imbedded in masses of jelly formed by gelatin- ization of the pedicels, teliospore-pores varying in number and arrangement; uredinia lacking........... Genus Gymnosporangium
Teliospores in definite sori, not becoming gelatinous.
Pycnia subcuticular, other sori subepidermal; teliospore-pores when more than one in a cell lateral; uredinia usually with encircling paraphyses.
Teliospore-wall more or less conspicuously laminate. Teliospores 2-celled, the wall finely and sparsely VErrhense Pees tes ess ke. 5 3 Be Genus Uropyzxis Teliospores 2 to several-celled, more or less coarse- ly verrucose or even smooth. Life-cycle with all spore-forms.............. aia hil aia eS OEY cc Sat Genus Phragmidium Life-cycle with pycnia, aecia and telia........ Be Abe. ee Genus Earlea Teliospore-wall not noticeably laminate. Teliospore-wall spinous, teliospores 3-celled by oblique septa................ Genus Nyssopsora Teliospore-wall nearly or quite smooth, the spores 2- or several-celled by transverse septa. Teliospores 2-celled....... Genus Gymnoconia Teliospores 3-13-celled...... Genus Kuehneola
58 F. D, KERN
Pycnia and other sori subepidermal; teliospore-pores one in a cell and apical; uredinia rarely with encircling paraphyses. Life-cycle with all spore-forms.
Teliospores I-celled ............... Genus Nigredo
Teliospores 2-celled .............. Genus Dicaeoma Life-cycle with pycnia, aecia and telia.
Teliospores I-celled ........... Genus Uromycopsis
Dehospores: 2-Celled:: .... « » s:0s\s was avon Genus Allodus Life-cycle with pycnia, uredinia and telia.
Teliospores 1-celled .............. Genus Klebahnia
Deliospores | 2-celled ooo o was ece se Genus Bullaria Life-cycle with pycnia and telia, or only telia.
Delospores. I-celled> 266. sss aesc Genus Telospora
Teliospores 2-celled .............. Genus Dasyspora
GENUS RAVENELIA BERK.
This genus is especially characterized by the manner in which the teliospores are fascicled on compound pedicels. The spores form heads which are bordered by hyaline cysts that swell more or less in water. The urediniospores are often paler below. The genus occurs, with the exception of one species, upon leguminous hosts included in the families, Mimosaceae, Caesalpiniaceae, and Fabaceae. The exception is on Phyllanthus belonging to the Euphorbiaceae. Thirty-eight species have been described in North America, chiefly from Mexico, Central America, and the West Indies. Several occur along the southern border of the United States but only one comes into the central and northern states, R. epiphylla (Schw.) Diet. on Cracca (Tephrosia).
GENUS TRANZSCHELIA ARTH.
A small genus, only two species at present known. The uredin- iospores have the wall thicker and less echinulate above. The tel- iospores are 2-celled and a characteristic feature about them, aside from the manner in which they are borne, is the ease with which the two cells separate. One species, T. cohaesa (Long) Arth., known only from Texas, is autoecious on Anemone decapetala; the other, 7. punctata (Pers.) Arth., is widespread and heteroecious, O and I on Anemone, Hepatica, and Thalictrum, II and III on
peaches, cherries, and plums.
GeNuS PoLyTHELIS ARTH.
A small genus which is confined to hosts of the family Ranun- culaceae. The teliospores are very similar to those of Tranzschelia but the two genera differ very markedly in the life-cycle. A species having both cells of the teliospores globoid is P. fusca (Pers.) Arth. on Anemone quinquefolia common east of the Mississippi; another with the lower cell considerably elongate, on Pulsatilla hirsutissima, is P. Pulsatillae (Rostr.) Arth. common from the Mississippi to
—ey-” ~-
PLANT RUSTS 59
Colorado and Montana; and a third with the lower cell somewhat elongate, on Thalictrum, is P. Thalictri (Chev.) Arth., distributed throughout the northern United States and Canada.
GENUS GYMNOSPORANGIUM HeEbw. F.
Characterized, with a few exceptions, by a dingy-white, mem- branous peridium, which elongates into a tubular form and tends to rupture along the sides; by large peridial cells usually conspicu- ously sculptured on the inner and side walls (see Fig. 4, a); by aeciospores with colored walls and evident germ-pores*; and by teliospores with hyaline pedicels of considerable length, the outer portions of which swell in moisture and become gelatinized to form a jelly-like matrix in which the spores appear imbedded. As regards hosts the genus is restricted in its aecial stage to the family Malaceae (Pomaceae), with three known exceptions, and in its telial stages to the Juniperaceae without any known exceptions. About thirty species have been reported in the United States, of which the fol- lowing are most likely to be collected.
Species
G. Juniperi-virginianae Schw. (G. macropus Link). The com- mon “orchard rust” forming globoid galls on the Virginia red cedar in the telial stage and attacking crabapples and cultivated apples in the aecial stage. The telia on the galls are cylindrical, the galls die after producing a crop of telia.
G. globosum Farl. Also forming telia on the red cedar but chiefly on the genus Crataegus in its aecial stage. The telia are wedge-shaped and the mycelium in the galls is perennial, produc- ing new telia between the scars of the sori of previous seasons.
G. germinale (Schw.) Kern (G. clavipes C. & P.). The hem- ispherical telia in this species do not form galls but long gradual enlargements of the twigs or branches. The aecia attack the fruits and often the twigs of Cydonia (quince), Amelanchier, Aronia, and Crataegus. The peridium is unusually whitish. The telia occur not only on the red cedar (Juniperus virginiana) but also on the junipers (Juniperus communis and J. siberica).
Along the Atlantic coast are two conspicuous species on the branches of
4. In most genera germ-pores are apparently wanting or obscure in the aeciospores but are usually evident in the urediniospores and teliospores.
60 F. D. KERN
the white cedar (Chamaecyparis thyoides); G. Ellisii (Berk.) Farl. with yellowish filiform telia and G. Botryapites (Schw.) Kern with brownish pulvinate sori. G. Betheli Kern is a gall form very destructive to the red cedar (J. scopulorum) in the Rocky Mountains; G. guvenescens Kern in the same region causes witches’ brooms on the cedars.
GeNuS Uropyxis SCHROT.
A genus usually separable from all others here described by the laminate wall of the teliospores, the outer layer of which is gelatin- ous, swelling in water. The species are more common southward into Mexico. U. sanguinea (Peck) Arth. on Mahomia (Berberis) is distributed throughout the western mountain region from Wash- ington and Wyoming south to Guatemala. U. Amorphae (Curt.) Schrot. on Amorpha is widely distributed over the United States and especially abundant in the Mississippi valley. In the former the gelatinous outer layer is relatively inconspicuous, in the latter 1-3u thick at apex and base of spores and 7-15y at the sides.
GeNus PHRAGMIDIUM LINK.
The cycle of development in this genus includes all spore- forms and all species are autoecious. For hosts it is restricted to a single family, the Rosaceae. The aecia and uredinia are both without peridium but usually with encircling paraphyses (see Fig. 4, b). The teliospores are usually more than two-celled by trans- verse septa (Fig. 2, d). Sixteen species have been described in North America, four on the tribe Rubeae, eight on the tribe Roseae, and four on the Potentilleae. P. imitans Arth. on Rubus strigosus is the most widely distributed of the first group. P. disciflorum (Tode) James and P. subcorticinum (Schrank) Winter are com- mon on cultivated roses in many parts of the United States, espe- cially the northern states east of the Rocky Mountains. The tel- iospores of the former are 5-9-celled, with walls blackish-brown, opaque, 5-7p thick, of the latter 5-7-celled, the walls chestnut-brown, not very opaque, 3-5 thick; in both species the teliospore-walls are verrucose and the pedicels swell in water. P. Andersom Shear on Dasiphora fruticosa and P. Potentillae (Pers.) Karst. on various species of Potentilla are representatives of the third group. In P. Andersoni the teliospores are furnished with a hyaline papilla at the apex and the pedicel is much swollen in the lower part, while in the other the apex has no apiculus and the pedicel is not swollen.
PLANT RUSTS 61
Genus EarLEA ARTH.
This genus resembles Phragmidium but the cycle of develop- ment includes only pycnia, aecia, and telia. Several species have been referred here but only one of them is common, that on various roses. This species differs from the species of Phragmidiuwm com- mon on roses by the teliospores having smooth walls and pedicels not swelling in water and also by the fact that the telia are large and appear always upon the stems, while in that genus they are small and only upon the leaves.
Genus NyssopsoraA ARTH.
The teliospores differ from those of all other genera (except Triphragmium) in having the teliospores divided into cells by oblique partitions in such a way as to make them triangularly 3- celled (Fig. 2c). They differ from Triphragmium, which is not discussed in this paper, by the short life-cycle and the spinous char- acter of the teliospore walls. Only one species, N. clavellosa (Berk.) Arth. on Aralia nudicaulis is known east of the Rocky Mountains; another in the western mountainous region is N. echinata (Lev.) Arth. on Ligusticum and Oenanthe.
GENUS GYMNOCONIA LAGERH.
Here belongs the orange rust of blackberries and raspberries (Rubus spp.) which is so well known. It is the only species of im- portance and is best known under the name G. interstitialis (Schlecht.) Lagerh. The pycnia and aecia are the conspicuous stages; no uredinial stage exists.
Genus KuEHNEOLA (LINK) ARTH.
Another genus with several species on the Rosaceae but differ- ing from those already described on that family. The teliospores are smooth and few- to many-celled by transverse partitions. The aecial stage is lacking. K. obtusa (Strauss) Arth. with 3-5-celled teliospores is a common form on Potentilla canadensis; K. uredinis (Link) Arth. with 5-13-celled (usually 5-6) teliospores is another rust of Rubus, but is not at all conspicuous and can not be confused with Gymnoconia. One species, K. Gossypti (Lagerh.) Arth., is a rust of the cotton plant known from southern Florida and the West Indies.
62 F. D. KERN
Genus NicrEDo Rouss.
To this and the following seven genera belong most of the species formerly referred to the old composite genera Uromyces and Puccinia. By the use of the generic names here adopted the important information concerning the life-cycle is conveyed in the name without the necessity of the roundabout method of explaining the status with a phrase.
The aecia are usualy cupulate, aeciospores borne in chains with colorless, verrucose walls; the uredinia are without peridium or encircling paraphyses, urediniospores borne singly on pedicels, the walls colored, echinulate or verrucose, the pores variously ar- ranged; the telia are sometimes long covered by the epidermis, teliospores free, stalked, 1-celled (see Fig. 2a), the wall firm, colored, smooth or verrucose, with one apical pore. The genus Nigredo is represented by a large number of species, many of which are common in the United States. It will be possible to mention only a few of those most likely to be found.
Species
Host belonging to grass family (Poaceae). Urediniospore-pores 3 or 4, equatorial, the spores medium-sized (15-19 x18-23u) ; on species of Panicum, chiefly P. virgatum; I unknown. OER WE eB nin. 235s cared ue Sas kee N. graminicola (Burr.) Arth.
Urediniospore-pores about 8, scattered, the spores large (19-27x25-37p) ; on species of Spartina; I on Steironema, Polemonium, Phlox, and SS TE eI NS ous 0.5' 6, senile ok fe, Foe es N. Polemonii (Peck) Arth.
Host belonging to sedge family (Cyperaceae). Urediniospore-pores 4, equatorial; on Scirpus; I on Cicuta and Sium OR aac A ETE ROS o's co orc biecehij os Biante sauce N. Scirpi (Cast.) Arth.
Urediniospore-pores 2, above the equator; on Carex; I on Aster and
SOUIEGO cee TRIES <=) o.0.ereidte, came tore tine crete N. perigynia (Hals.) Arth.
Host belonging to’family Araceae; urediniospore-wall thicker above, pores 4; on Caladim > atitoectottse. .,.. 22250 blo Seeeene N. Caladii (Schw.) Arth. Host belonging to family Juncaceae; urediniospore-pores 2, equatorial; on Juncus; I on Ambrosia, Arnica, and Cirsium...... N. Junci (Desm.) Arth. Host belonging to family Polygonaceae; urediniospore-pores 4, equatorial; on Polygonum, autoecious.........5.esecceccece N. Polygoni (Pers.) Arth.
Host belonging to family Carophyllaceae; urediniospore-pores 3 or 4, equa- torial; on Dianthus (carnation); I on Euphorbia (not known in United BSEALES ) chs Rie AEE ELAR oe Se ee ey ae N. caryophyllina (Schrank) Arth.
—
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PLANT RUSTS 63
Host belonging to family Fabaceae. Urediniospore-pores 3-6, scattered; on Trifolium pratense (red clover) ;
DE eeakeiowal cgay. bee cee tes a c's s N. fallens (Desm.) Arth. Urediniospore-pores 3 or 4, equatorial; on T. repens (white clover; AULOCCIOUISAS eee Rie ee sate ede lela N. Trifolii (Hedw. f.) Arth. Urediniospore-pores 2, equatorial; on Strophostyles, Vigna, and Phaseolus (including “the garden :beafi); atitoecious...... 0's. i006 oe oc ee ences
FRA ony cone eo Once bene Oc re Ore N. appendiculata (Pers.) Arth.
Host belonging to family Asclepiadaceae; urediniospore-pores 4, equatorial ; on Asclepias; DiGMRROWH +e os ic. wl. ie eae. N. Howei (Peck) Arth.
GENuS DIcAEOMA S. F. GRaAy.
This genus resembles Nigredo in every important character, differing only in having teliospores with two cells. It is without doubt the largest of the rust genera. Here belong the bulk of grass and sedge rusts, including the important cereal rusts. Dicotyledonous plants of eighty or ninety genera representing about twenty-five families serve as hosts for species of this genus, but most of these are not of economic interest or of common occurrence.
Species
Host belonging to grass family (Poaceae).
Telia early naked, blackish, chiefly on the culms and sheaths; uredinio- spore-pores 4, equatorial; on wheat, oats, rye, timothy and several wild grasses (Agrostis, Agropyron, Elymus) ; I on barberry............... PEAS Paige ee ee Sik, SN ee eT SORT Siete el D. poculiforme (Jacq.) Kuntze
(=Puccinia graminis Pers.)
Telia long covered by the epidermis, often grayish-black; chiefly on the leaf-blades.
Urediniospore-wall brown; the pores about 6, scattered.
Urediniospores with intermixed paraphyses; telia rarely formed in our region; on species of Poa, common on blue-grass; I on Uitssulago! Lave: 5. .1srspee eter D. epiphyllum (L.) Kuntze
(=Puccinia poarum Niels.)
Urediniospores without paraphyses; teliospores germinating in the fall; on rye (Secale cereale) ; I on Lycopsis, not yet found #n CAmerGas 26 :2.4)s. siete Sages D. Asperifolii (Pers.) Kuntze
(=Puccinia rubigo-vera DC.) Urediniospore-wall yellow or colorless.
Teliospores with finger-like projections at the apex; on oats and wild grasses (Cinna, Holcus and others); I on buckthorn CRHOINNWS eS cia avaie it's atoeie sop tore stats D. Rhamni (Pers.) Kuntze
(=Puccinia coronata Cda.)
64 F. D. KERN
Teliospores with smooth apex; on wheat; I unknown.......... sminstcme MLR: os 4 viele oa'Sb ad D. triticina (Erikss.) Kern. (=Puccinia triticina Erikss.) Host belonging to sedge family (Cyperaceae). Urediniospore-pores 3 (in occasional spores 4), equatorial. Urediniospores large (18-26x24-39u) ; teliospores large (39-71u long) ; on species of Carex; I on Urtica..... D. Urticae (Schum.) Kuntze Urediniospores medium-sized (15-21x19-25u); teliospores medium- sized) ((37-SSuimlones: on 'CarevsiL ion: (Ribess. «ic: aan eens eee ryote tote cee elect at eRe he SIS pve Apts bolo he D. Grossulariae (Schum.) Kern. (=Puccinia Grossulariae (Schum.) Lagerh. Urediniospore-pores 2, in the upper part of spore. Urediniospores medium-sized (15-19x19-24u); teliospores medium- sized (35-50u long); on Carex; I on Aster, Solidago, and Eri- GEFAG ee eh onG hao c x oe sees D. Erigeronatum (Schw.) Arth. Urediniospores large (17-21x23-32u) ; teliospores large (42-65u long) ; on Carex; I on Sambucus.............. D. Sambuci (Schw.) Arth. Host belonging to composite family, genus Helianthus; autoecious.......... EA RRS Hh TES RSS EAS REPRE PE ae RORY A EAS D. Helianthi (Schw.) Kuntze
GENus Uromycopsis (ScHROT.) ARTH.
The character of the pycnia, aecia, and telia are essentially like the genus Nigredo, but the uredinial stage is wanting. The telia often arise within the aecia or about them from the same mycelium. A good example of the genus is U. Psoraleae (Peck) Arth. on var- ious species of Psoralea from Minnesota, Illinois and Texas west- ward to the Pacific coast. The genus is more common westward.
Genus ALLopus ARTH.
This genus bears the same relation to Dicacoma that Uromy- copsis does to Nigredo. A. Podophylli (Schw.) Arth. is a com- mon and widely distributed species, occurring on Podophyllum pel- tatum. The teliospore-walls of this species are especially interest- ing on account of the straight or curved conspicuous spines with which they are beset.
GENUS KLEBAHNIA ARTH.
No cupulate aecia are present in this genus, the pycnia being followed by a stage of the uredinial-type. Only a few species have been referred here of which the more common one is K. Glycyrr- hizae (Rabh.) Arth. on Glycyrrhiza. This is found from North Dakota and Kansas westward.
PLANT RUSTS 65
Genus Butraria DC.
Resembling Klebahnia except for the possession of teliospores having two cells. A widespread species is on various members of the family Cichoriaceae, Hieracium, Agroseris, Nothocalais, and Crepis, for which the oldest name seems to be B. Hieracit (Schum.) Arth. The teliospore-walls are finely verrucose and uniformly thick, I-1.54. Another species on false boneset (Kuhnia) is B. Kuhniae (Schw.) Kern (Puccinia Kuhniae Schw.) with telio- spore-walls smooth and thicker above, 3-4 at sides, 5-7» above.
GENERA TELOSPORA ARTH. and Dasyspora B. & C.
To these genera belong species with short life-cycles. In some the teliospores germinate only after a resting period (micro-forms), in others they germinate at once (lepto-forms). The telia are usual- ly compact and arranged in circinating or crowded groups. Most specimens showing teliospores germinating upon maturity can be placed here with considerable confidence, as they very rarely be- long to genera with other spore-forms in the life-cycle. The I- celled forms belong to Telospora, and the 2-celled forms to Dasys- pora. Only a few species are known in the former genus. Telo- spora Rudbeckiae (A. & H.) Arth. on Rudbeckia laciniata is the most likely to be met with. Dasyspora is a large genus. D. Ane- mones-Virginianae (Schw.) Arth. on Anemone and D. Xanthu (Schw.) Arth. on Xanthium are of common occurrence.
FORM-GENERA
In addition toethe forms of known life-cycle, which may be re- ferred to true genera, there are many forms whose life-cycle is too imperfectly understood to permit them to be placed with confidence in any of the known genera. Many of these can be recognized merely as a stage and judging from analogy it is safe to assume that they cannot be independent but must be associated with other stages. In order that such forms may have names so that they may be dis- cussed more easily the practice has grown up of using certain terms as if they were really generic names, when in fact they rep- resent only stages. For example aecial forms of the usual cluster- cup type whose connections are unknown are placed under Aeci- dium; aecial forms of the blister-type inhabiting the pine family
66 F. D. KERN
(Pinaceae) are treated by most writers under Peridermium; while aecial forms lacking a peridium are considered under Caeoma. Uredinial and other similar looking stages are referred to Uredo. These names which are accorded generic treatment, but which in- clude only isolated stages, are referred to as form-genera, and as such they serve a useful purpose in disposing of the residue of im- perfectly known forms.
Agricultural Experiment Station. Purdue University.
BIBLIOGRAPHY ArTHUuR, J. C.
North American Flora, Vol. 7, Part 2 (1907), Part 3 (1912) ; pub. by The New York Botanical Garden. In this work are given keys, descriptions, synonomy, hosts and distributions. The genera are treated essentially in the order given in this paper and the parts published extend through the genus Nigredo.
Terminology of the Spore-Structures in the Uredinales. Bot. Gaz. 39: 219-222. 1905.
Clues to Relationship among heteroecious Plant Rusts. Bot. Gaz. 33 :62- 66. 1902.
Problems in the Study of Plant Rusts. Bull. Torrey Bot. Cl. 30 :1-18. 1903.
North American Rose Rusts. Torreya g:21-28. 1909.
CarRLETON, M. A. °
Investigations of Rusts. U.S. Dept. Agric., Bureau Plant Industry, Buil.
No. 63 (1904).
Cereal Rusts of the United States. U.S. Dept. Agric., Div. Veg. Phys. & Path. Bull. No. 16 (1899).
Cuinton, G. P.
Heteroecious Rusts of Connecticut having a Peridermium for their Aecial Stage. Report of the Botanist for 1907, Conn. Agric. Exper. Station (1908), pp. 369-396, with several plates.
FREEMAN, E. M. and Jounson, E. C.
The Rusts of Grains in the United States. U. S. Dept. Agric., Bureau of Plant Industry, Bull. No. 216 (1911).
PLANT RUSTS 67
Jounson, A. G. The Unattached Aecial forms of Plant Rusts in North America. Proc. Indiana Acad. Science for 1911, 375-413 (1912). Enumerates 1o1 forms, with data concerning hosts and localities.
Kern, FRANK D.
Methods Employed in Uredineal Culture Work. Proc. Indiana Acad. Science for 1905, 127-131 (1906).
The Morphology of the Peridial Cells in the Roesteliae. Bot. Gaz. 49: 445-452, with plates XXI & XXII. toro.
The Rusts of White and Red Clover. Phytopathology Vol. 1, pp. 3-6. IQII.
A Biologic and Taxonomic Study of the genus Gymnosporangium. Bull. N. Y. Botanical Garden Vol. 7, No. 26, pp. 391-483 (1011), illustrated.
Orton, C. R. Correlation between certain species of Puccinia and Uromyces. Mycolo- gia Vol. 4, pp. 194-204 (1912), illustrated.
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DEPARTMENT OF NOTES, REVIEWS, ETC.
It is the purpose, in this department, to present from time to time brief original notes, both of methods of work and of results, by members of the Society. All members are invited to submit such items. In the absence of these there will be given a few brief abstracts of recent work of more general interest to students and teachers. There will be no attempt to make these abstracts exhaustive. They will illustrate progress without at- tempting to define it, and will thus give to the teacher current illustrations, and to the isolated student suggestions of suitable fields of investigation [Editor.]
NOTES ON SOME PECULIAR SENSE ORGANS FROM DIPTERA
The Diptera are generally conceded to be descended from four- winged ancestors, the posterior pair of wings having become rudi- mentary. The rudiments of this posterior pair of wings are called halteres, and are found as small club-shaped organs just back of the normal wings.
These organs play an important part in the orientation of the body during flight. If they are removed or otherwise interfered with, the flight is disturbed and in some cases prevented.
At the base of the stalks of the halteres are to be found some highly developed organs, which appear to be sense organs.
In Figs. 1 and 2 which are drawn from an Ortalid, called Stranzia longipenis, will be seen a dorsal and a lateral view of a halter. There are apparently two kinds of sense organs depicted here, one (A) and (C) situated on opposite sides of the stalk, and one (B) situated on the chitinous sheath which covers the base of the organ on the dorsal side. (See Plate I).
Fig. 2 shows a side view of the halter. These sense organs when viewed with a higher power present an appearance something like Fig. 3. There are ten rows of the oval disks, with as many rows of rudimentary hairs or spines between them. Organs (A) and (C) are identical in these particulars. These oval disks have a swelled or crowning surface, which leaves them distinctly raised in rows.
In Fig. 4, is a diagram of the disk arrangement of the basal sheath. Here the disks lie in rows between chitin ridges, those nearest the center being nearly overgrown with small spines.
70 NOTES, REVIEWS, ETC.
An explanation of the nature and function of these organs is not certain nor easy. The following is offered as suggestive.
Let us look for a moment at the more primitive type of fly; we may find here a clue to the course these structures may have followed in their evolutionary degeneration.
In the Brachycera, we find a type of insect which has very simple forms of wings, the venation being mostly absent except for a few parallel ribs which run lengthwise of the wing. The wings are covered with spines which lie in rows alternating with each other as in Fig. 7. The halteres still retain their wing shape and the spines on them preserve the arrangement found on the anterior wings.
In another family still more highly organized, we find the rows of spines more definitely gathered and specialized into rows, which rows of spines are separated by spaces such as are seen in Fig. 5.
Finally, in the elaborate organization of the soaring and pois- ing flies we find, as described above for Stranzia, the rows of hairs or spines alternating with the rows of disks. Microtome sections of these organs show the oval disks as hollow and filled with fluid during life.
The rows of degenerate spines seem to be connected with the central nervous system, and are assumed to be sensory.
From a histological standpoint the halter is composed of an ectodermal layer of cells, which secretes the chitin with its many sensory spines, and an interior mass composed of trachea, nerves, and fluids with corpuscles. See Fig. 9 for a very diagrammatic view of a section of the halter.
Fig. 8 is a much enlarged view of the cells in the sense organ on the stalk of the halter. The disks are formed from large oval cells (A), and the sensory cells are at (B).
The writer is unable to say whether the disc cells are also sensory; altho it is possible that they are. It seems at least prob- able to him that they may be considered as homologous with the ordinary smooth membrane interspinal spaces on the normal wing. It is not clear from the structure of these organs just how they contribute to equilibrium, unless in some way they control the blood supply to the vascular terminal bulb.
Sete
AMERICAN MICROSCOPICAL SOCIETY 71
Some experiments conducted to determine what relation these sense organs on the halteres have to flight and to orientation in flight may prove interesting to those who have not made special study of the subject.
In order to determine the relation of the halteres to flight the writer removed the entire halteres, by cutting, in a number of specimens of Muscidz. Flies so treated were all incapable of con- trolling their flight, usually pitching violently downward when at- tempting to fly.
A similar number of flies was taken, and, without removing the halteres, a small amount of liquid balsam was introduced under the sheath and over the sense organs. Specimens treated in this way could not be induced to undertake flight.
These two experiments show clearly that the halteres play an important role in equilibrium in flight, and that they can be put out of commission, as effective organs, without actual removal. This suggests the existence of certain subordinate parts on which the functioning of the organ depends.
It now remains to localize, if possible, the responsible portion of the halter. In doing this, larger flies, as Sarcophagide, Syrphidz, and Tachinidz, were used. An effort was made in these flies to injure the structures referred to above as sense organs, and to confine the injury to these. Cauterization with a hot needle was attempted; but this was difficult to control, and often resulted in too extensive a wound. The other method used was the appli- cation to the so-called sense organs of a small amount of nitric or sulphuric acid, without allowing it to reach the terminal bulb. The flies were held for a minute or so to allow the acid to act. Insects treated in this way pitch headlong in attempted flight much as those whose halteres were removed. Some forty specimens were so treated. One of two conclusions seems necessary :—either the acid penetrates and essentially destroys the whole organ, or there is a special sensory portion which was destroyed and prevented the ordinary reaction.
The conclusions which the writer thinks reasonable are:
1. The halteres are necessary to successful balancing in flight in Diptera.
N to
NOTES, REVIEWS, ETC.
2. The peculiar and definite organs at the base are sense organs, and are necessary in giving the halteres functional value.
3. These sense organs are in some way aroused by the changes in position, and thru them the central nervous system is enabled to control the process of balancing.
A CONVENIENT DROPPER FOR USE IN CUTTING CELLOIDIN SECTIONS
A very useful aid in cutting celloidin sections is shown in the accompanying figure (Plate Il). This piece of apparatus was in stock when the writer assumed charge of this laboratory, and he is not acquainted with its history. While it is not listed in any of the dealers’ catalogs that the writer has examined, it may be made at a very slight cost in any machine shop.
It consists of a glass oil-cup (1) of about 40 cc. capacity, with a mill-head (2) at the top to regulate the flow of alcohol. The cup is fastened to a bar (3), which is slotted for about 34 its length to receive the bolt that extends through the column (4) that holds the cup a few inches above the knife (5). The head of the bolt men- tioned above is of the proper shape to fit into the slot in the knife- carrier, and the thumb-nut (6) on the other end of the bolt tight- ens at one time both the bar (3) to the column (4) and the column to the knife carrier. This thumb-nut and its bolt, which, except in length, are exactly those (7) that hold the knife in position, make it possible instantly to adjust the cup so that the alcohol will fall on any desired part of the knife; and since the apparatus is attached to the carrier it will always be over the same part of the knife even in microtomes where it is the knife that moves. If all the metal parts are nickel-plated it will obviate trouble in drying off the alco- hol to prevent rusting.
A. M. REESE. Department of Zoology, West Virginia University.
CRITICAL ILLUMINATION FOR THE MICROSCOPE
In a brief paper (J. Queck. Micr. Club. Nov. 1912) Reid gives some important suggestions for critical illumination, which will cer- tainly be of value to beginners in the use of the microscope and to many older users who have not given critical attention to the sub-
474 0,0.00,0 0,0,02° Fig. 3 Res preccemetees - a Np Se TOON — Bese ie = e— cdhh4dd44a4 Fig. 5 ae
PLATE | Sense Organs of Diptera
PLATE I] Dropper for Celloidin Sectioning
AMERICAN MICROSCOPICAL SOCIETY 73
ject. There is little question that most of us, reared in school labor- atories, do not get the nice, exact results in the use of microscopes which are obtained by the thorogoing students of microscopy.
Certain simple precautions leading to good illumination intro- duce the paper :—Cut out all unnecessary light from the room, so that no light gets to the eye except thru the microscope; save the best eye for critical moments by using the other eye for prelim- inary steps; use color screens complementary to the stains used, green for red, yellow for blue, etc. The subject of illumination itself the author discusses under these heads: The most suitable light; collecting lenses; principles of correct illumination both of the field and of the object itself ; condensers; distance of lamp from substage mirror; critical and non-critical illumination; working aperture; general arrangement of light and apparatus in high, medium, and low-power work.
For the detailed discussion of these topics the readers must be referred to the original paper.
CLEANING DIATOMS
Blake (Am. Jour. Sci. Jan. 1913) calls attention to the interest in cleaning, mounting, and study of diatoms. After recounting the difficulties attendant on the usual methods he describes a method originated by himself some twenty years ago.
Instead of the older method of treating with acid, diluting with water, and repeated decanting, the author devises an organic seive made by cementing a thin cross-section of some coniferous wood to a small glass vial whose bottom has been cut off for the purpose. The wood is cut about one-quarter millimeter in thickness, from a suitable piece of wood kept until the operation in boiling water. This is done by means of a sharp, thin-edged chisel.
The operation of cleaning the diatoms consists of placing the digested diatom material, moderately diluted, in the vial, and by means of a suitable rubber compression bulb, alternately pressed and released, of forcing the acids and salts thru the seive, and the clay and fine sand thru or into its pores. These diatoms which are longer than the diameter of the pores will remain behind with larg- er grains of sand which must be removed in some other way.
74 NOTES, REVIEWS, ETC.
It is necessary to see that the strainer does not become choked This may be prevented by shaking. The strainer should, of course, be kept in water between uses. When it finally becomes clogged with sand, a new one must be put on.
By using wood with different sized conducting vessels, a sort- ing of the diatoms may be affected. By using pine, spruce, white wood of the red cedar, a graded series of strainers can be had, the last being much finer than the first.
STAINING PROTOZOA
Darling (Science: Jan. 10, 1913) calls attention to the dearth of knowledge of the acidophilic substances in the nuclei of protozoa, owing to the predominant use of basophilic staining substances, and to the “lack of a satisfactory technic for demonstrating acidophilic substance in wet fixed films.”
The author suggests careful differentiation of such polychrome stains as Romanowsky or Hastings-Giemsa, by ammoniated ethyl alcohol. Under such conditions, studying Entamebae, he found a definite arrangement of an acidophilic substance (oxychromatin) within the nucleus, showing a structure quite different from that shown with the usual basichromatin stains. He believes that care- ful and critical study will reveal that this oxychromatin may have important functional relations to the changes that are so well known in the true chromatin in nuclear activity.
DOUBLE-STAIN METHOD FOR THE POLAR BODIES OF DIPHTHERIA BACILLI
Dr. Marie Raskin (Apoth. Ztg. XX VII, p. 10; Abstr. United St. Naval Med. Bull. Vol. 6, No. 4, p. 611) proposes a technic for these bodies, whose distinctive value lies in the fact that only two operations are necessary, i. e., the application of a stain with both colors present, then water washing.
Formula for stain :—
Glacial (Acefie Acid.) 2% 22608 BGe: Dist: Watert19.425. 428, aR gg) * Ade A G5G6) 2 ivi A a ee 100 “ Old Sat. sol Methylene blue..... 4 “
Ziehl’s phenol fuchsine Sol..... 4
AMERICAN MICROSCOPICAL SOCIETY 75
Drop mixture in a thin layer over the specimens on the cover glass; heat through the flame. The alcohol ignites and is permit- ted to burn off, after which the specimen is washed in water and dried. The entire process takes 20-25 seconds, and the stain re- mains serviceable for any length of time. Polar bodies appear deep blue and the bacilli bright red. Even in smears with a preponder- ance of other bacteria, individual diphtheria bacilli may be readily and unmistakably identified.
A NEW TECHNIC IN STAINING DIPHTHERIA SPECIMENS WITH TOLUIDIN BLUE
Dr. Constant Ponder (Lancet, July 6, 1912; Abstr. U. S. Naval Med. Bull. Oct. 1912, p. 612) recommends the following treatment for diphtheria bacilli :—
The stain: Toluidin blue (Grubler)....0.02 gram. Glacial acetie acide: 20.) 2t EMEC. ADSHAlOR) SNE OIN Heh are Distilled Water to make..... 100 ‘“
The film made on cover glass is fixed as usual. Spread stain on film. The cover glass is then turned over and mounted as a hang-drop preparation. Typical diphtheria bacilli are said to stain blue, with red granules. The author gives this as a new method, and says it is preferable to either Methylene blue or Neisser’s stain.
NOTES FROM MEETING OF THE ILLINOIS MICROSCOPICAL SOCIETY, Chicago, Oct. Io, 1912
Mr. N. S. Amstutz showed a useful contrivance for keeping pond life in place. It consisted of a piece of brass about 7/8 in. square and 5/32 in. thick. A series of seven holes were drilled thru it so as to imprison that many varieties of pond life at one time. The plate was placed in a flat bottomed watch glass and each specimen transferred with a pipette to its proper “cell.” These could be then studied at will very nicely with a 2/3 objective and various combinations of oculars. The specimens were confined laterally so they were unable to move out of the field of view though having abundant room for vertical movement. With the coarse ad-
76 NOTES, REVIEWS, ETC.
justment the up and down variation could easily be followed. It proved a great satisfaction to examine water fleas, mosquito larvae, etc., when fenced in. The holes were arranged 6 in a circle of 1/2 in. diameter and the seventh in the center. Their diameter was de- termined by measuring the diameter of the field with a stage micrometer and then selecting the next smaller size of twist drill by which to do the drilling. To guard against the smallest animalcule creeping between the brass and the watch glass the bottom face could be covered with a thin film of balsam, air dried until quite of proper consistency, and then a cover glass pressed into intimate contact, so that no balsam would run into the spaces. Vipa A. LATHAM, Secy.
BOG SOLUTIONS AND PLANTS
Dachnowski (Bot. Gaz. Dec. 1912) writes on the physiological effects of peat or bog solutions on the plants subjected to them. It has been clearly established that the nature of these organic solu- tions and of the bacterial flora maintaining life therein is a very im- portant factor in limiting the higher life of these regions. The fact that some plants tolerate these conditions and others do not makes clear a difference in the plants themselves. The writer is endeavor- ing to see what it is that makes this difference in plants exposed to the solutions. The responsibility must rest either upon difference in diosmotic qualities of the plasmic membranes, or upon differences in cytoplasmic resistence, or on both. He finds the following facts which help to localize the solution of the problem: (1) Some plants may cause the precipitation of the hurtful materials in the solu- tions in an insoluble form, by enzymic action. This conceivably may take place outside the membrane, inside the cell ; or in the mem- brane itself, affecting its permeability ; (2) other plants may possess the power of assimilating with impunity these organic substances.
It is well known that these solutions have little effect on certain xerophytic plants, while they totally inhibit agricultural plants. The value of the work is evident as bearing on the agricultural use of peat lands, on the nature of xeromorphy itself, as well as on the successions of vegetation in the bogs.
AMERICAN MICROSCOPICAL SOCIETY 77
EFFECT OF CROPPING ON SOIL BACTERIA
Brown (Centralbl. Bakt. Abt. 2, XXXV, 1912, p. 248) has studied the effect of different kinds of cropping on the bacterial content of the soil. He finds that the number of microorganisms in the soil is much increased by rotation of crops as compared with continuous cropping. The same is true of the nitrifying and nitro- gen-fixing powers of the soil. He compares various systems of alternation of crops in this regard. He also discusses the effect of turning under clover, as green manure. He claims that the two year rotation with green manuring is not so effective in increasing the bacteria and bacterial products as the longer term rotations. It is shown that the productivity of the soil is closely related to the bacterial activities within it.
ALTERNATION OF GENERATION IN THE PH/ZO0PHYCEZ
In a beautifully illustrated article (Bot. Gaz. Dec. 1912) Yamanouchi gives, from the study of the nuclear and experimental conditions, the grounds for believing that Cutleria multifida is the gametophytic phase of a species of which Aglaozonia reptans is the sporophytic stage. The nuclei of both male and female Cutleria plants contain 24 chromosomes, which is true also of the gametes themselves. The sporelings resulting from the union of these gametes contain 48 chromosomes and develop into an Aglaozonia form similar to A. reptans in nature. On the other hand the nuclei of Aglaozonia reptans contain 48 chromosomes, which is reduced in zoospore formation to 24. These zoospores germinate without conjugation, and produce plants similar to young Cutleria in nature, and with 24 chromosomes.
EXPERIMENTS ON THE GERMINATION OF TELEUTOSPORES
Dietel (Centralbl. Bakt. IT. 31:95. 1911) reports on the effects of age and temperature and drying, etc., on the germination of teleutospores of Melampsora. In the early spring these spores germinate in about 3 days if brought into favorable conditions of temperature and moisture. As the spores grow older the time necessary to germinate decreases. This might be due either to in- ternal ripening or to the progressive changes in the spring tempera-
78 NOTES, REVIEWS, ETC.
ture. Temporary drying hastened germination; strong light de- layed it; temporary freezing had no effect. Germination takes place at 6°-10° C., but is hastened by higher temperature of 15°-20°.
DIRECTION OF LOCOMOTION IN STARFISH
Cole (Jour. Exp. Zool. Jan. 1913) finds that Asterias forbesi in the absence of directive stimuli, in crawling advances most frequently with that part of the body forward in which the madreporite occurs. He found a tendency in these animals to persist in moving with the same parts foremost in a series of succeeding trials; tho there is also a tendency to shift or “rotate” this anterior point successively to other parts. The author thinks the madreporic body may be what determines anteriorness, and shows that the “physiological an- terior” of the starfish corresponds in this respect to the anterior parts of the more bilateral spatangoids.
A ROTIFER PARASITIC IN EGG OF WATER SNAILS
Stevens (Jour. Queck. Micr. Club., Nov. 1912) describes a rotifer of the genus Proales which is able to bite a small opening in the tough egg membrane of the snail Limnaea auricularia, and by squeezing thru this enters the more fluid portion within. The rotifer feeds on the fluid gelatin of the egg with an occasional attack on the snail embryo itself. As the result of these attacks the snail embryo is finally killed.
In the meantime the rotifer lays its eggs, and later leaves this to enter still other eggs. The larvae hatch and undergo their de- velopment, devouring the dead snail embryo and other available substance of the egg. They too later escape and enter other eggs.
This looks somewhat like a parasite in the making. The author says the rotifers do not seem “at home” in the water while making their way from egg to egg.
EUGLENIDS AND THEIR AFFINITIES
Alexieff (Arch. Zool. Exp. Notes et Rev., No. 4. 1912) in con- nection with the discussion of certain euglenoid forms that are partly or largely parasitic on other animals, makes some interesting sugges- tions as to the relationships of Protozoa. He thinks the Euglenids
AMERICAN MICROSCOPICAL SOCIETY 79
are near the flagellate source of the Sporozoa, and from thence as a main stem arise the Trypanosomes, Coccidians, Gregarines, Haemogregarines. He feels also that the Euglenids may give rise to lines leading to Cystoflagellates and Ciliates.
AN AMEBA WITH TENTACLES
Collin (Arch. Zool. Exp. N. & R., No. 4. 1912) describes a new protozoan combining the characters of Ameba and the Suctoria. The organism has a gelatinous covering whose form is easily changed, and possesses tentacles by which it attaches itself to objects. It has the nuclear and pseudopodial structure of the Ameba. It is a marine form occuring in a culture of seaweed along with other amebz and Foraminifera.
SOME AMERICAN RHIZOPODS AND HELIOZOA
Wailes (Jour. Linn. Soc. Dec. 17, 1913) reports 161 species and varieties of Rhizopods and 4 species of Heliozoa from collections made in 1911 at Augusta, Georgia, in New Jersey, and at various points in New York. Comment is made upon the small amount of work done on the American species of these groups since the time of Leidy.
Of these, 5 species and 10 varieties are new. Forty of them are recorded for the first time from the United States. About 80% of the species are similar to those found in Europe. The remainder are made of species rarely or not at all found in Europe. The author states that considerable local variation exists in some of the species.
SIZE OF CHROMOSOMES AND PHYLOGENY
_ Meek (Jour. Linn. Soc. Sept. 24, 1912), thru a study of the diameters of chromosomes, has reached the conclusion that there are three diameters of chromosomes found in animals,—.2Ip in Protozoa, .42 in low Metazoa, and .83u in high Metazoa. He holds that these measurements are remarkably constant. This arith- metic progression is believed by him to mean a lateral fusion of these chromatic elements in phylogeny.
In respect to length, the author finds, by study of spermatogen-
8o NOTES, REVIEWS, ETC.
esis in several species of Stenobothrus that the chromosomes of the spermatocytes are made up of rods, sometimes 2 and sometimes 4. The length of these rods varies in arithmetic progression. In each of 4 species studied there are 5 short chromosomes, no two of which are the same length; altho the 5 short chromosomes in one species correspond with the 5 short ones of the others. There are also 3 larger chromosomes in each species, but these long chromo- somes do not belong in the different species to the same numerical series. The author believes that the external specific differences between the species are dependent on the differences in the long chromosomes, altho he is unable to establish the correlation between the rod-lengths and the body characteristics.
SPERMATOGENESIS IN HYBRID PIGEONS
Smith (Quart. J. Mic. Sci. 1912, p. 159) reports studies of the sperm formation and structure in the hybrids formed by mating a male pigeon and female domestic dove, and compares these with the condition in pure breeds.
In the first maturation division in the hybrids the chromosomes do not unite to form 8 bivalent chromosomes but occur quite ir- regularly about the spindle and are finally distributed to the poles irregularly.
The second maturation division is practically suppressed. The secondary spermatocytes proceed at once to form spermatids and spermatozoa. Many of these are on the average twice the normal size, altho otherwise apparently normal structurally. In other cases there were structural abnormalities.
It is known experimentally that hybrids of these stocks are in- fertile, and it seems that the sterility may be due to the inability of the specifically different chromosomes to unite in the normal synapse, with the consequent disturbance in the whole maturation process.
MALE GERM CELLS IN NOTONECTA
Browne (Jour. Exp. Zool. Jan. 1913) discusses the differences in form and number of the chromosomes in three species of Noto- necta. She finds that the differences in the chromosome condition may be explained in these species by the relations of two particular
ee
AMERICAN MICROSCOPICAL SOCIETY 81
chromosomes. In N. undulata the two chromosomes in question are always separate; in N. irrorata are always united to form a single body; and in N. insulata they may be separated in the first spermatocyte division, but are united in the second.
The author traces the origin of the chromosomes from the karyosphere in the three species, and their behavior in the growth stages and maturation divisions.
INTERSTITIAL CELLS OF TESTIS AND SECONDARY SEX CHARACTERS
J. des Cilleuls (C. R. Soc. Biol. Paris, 1912, p. 371) finds a strict coincidence in the development of the interstitial cells of the testis and the secondary sexual characteristics of the cock. In chickens the external marks of sex do not begin to appear until about the thirtieth day. By the time the chicks are 45 days old the pullets show a greater development of the tail feathers and the cockerel more color and size of comb. The sex distinctions increase from this point. The author claims that the secondary sex characters in the male bird begin to show with the oncoming of the interstitial cells, and increase as these increase. The author believes that the secretion of the interstitial cells acts as a hormone in stimulating the growth of the characteristic male secondary structures.
MICROBIOLOGY IN RELATION TO DOMESTIC ANIMALS
This book, entitled “Principles of Microbiology,” with a sub- title “A Treatise on Bacteria, Fungi, and Protozoa Pathogenic for Domesticated Animals,” is written primarily for veterinary stu- dents beginning the study of microbiology. It consists, in about equal parts, of matter belonging to general bacteriology and to spe- cial applications of this to veterinary science. In the very nature of the case this makes the treatment of general bacteriology somewhat less satisfactory than may be had from text-books on this subject, and limits the author somewhat in his treatment of the part of the subject which is peculiar to the book.
The first twelve chapters are given to such subjects as the biology, morphology, classification of bacteria; the apparatus, meth- ods of sterilization, cultivation, staining, and examination of bac- teria; the relation of bacteria to disease. In the part relating to
82 NOTES, REVIEWS, ETC.
the work of the veterinarian there are, first, two introductory chapters dealing with the Use of Animals in Bacteriological Exam- inations and Investigations, and the Bacteriology of Water and Milk. These are followed by eight chapters dealing with the various prin- cipal genera and species of microdrganisms that produce diseases in domestic animals, together with their pathogenesis and, where known, the treatment. These chapters present very valuable ma- terial for the general student of biology, as well as for the vet- erinarian.
In the concluding chapters the author discusses some of the broader questions of physiology, theory, diagnosis and therapy of the bacterial diseases under the heads:—Specific Bacterial Pro- ducts, Tissue Reactions and Immunity ; Serum Diagnosis ; Immunity and Vaccine Therapy. This resumé is very readable and valuable to the general student. The mechanical excellence of the book is all that could be desired.
Principles of Microbiology, by VY. A. Moore. Pages 506; illustrated. Carpenter & Co., Ithaca, N. Y. Price $3.50.
BEGINNERS GUIDE TO THE MICROSCOPE
This is an elementary handbook designed to aid the untechnical person to use the microscope for his own pleasure and that of his friends. The need of such a book seems to the author to lie in the great complexity of the modern instrument and the wealth of its accessories, and in the elaborate character of the modern books about the microscope. In a very simple, gossipy way quite suitable to his expressed purpose, the author describes the microscope and its essential parts, the formation of images, illumination; discusses the principles that should guide in the choice of an instrument ; gives rules for the use of the instrument and for its care; tells of interest- ing objects for temporary mounts. There are also sections on the home aquarium, on collecting objects, on mounting for permanent display, and on storing slides.
In many ways it is much to be regretted that there are not more of our modern Americans who turn to such methods of interest and diversion as are suggested here. The use of the microscope as a serious instrument of education and research in schools has in-
AMERICAN MICROSCOPICAL SOCIETY 83
creased greatly in this country; but it is remarkable that so few
people use it as a means of recreation, pleasure, and general culture. The Beginners Guide to the Microscope, by Chas. E. Heath, F. R. M. S. Illustrated; 120 pages. Price 1 shilling. Percival Marshall & Co., London.
MICROSCOPY AND DRUG EXAMINATION
In this little book the author seeks to present in a simple and condensed form the elements of microscopy and histology demanded by pharmaceutical students. In Part I, which is given to Micro- scopy, are discussed briefly,—often too briefly to be satisfactory,— microscopes, microscopic photography, manipulation and care of the microscope, reproduction and measurements of microscopic ob- jects; histology, microchemistry; the preparation and mounting of microscopic objects; cells; plant and animal tissues; microscopy of starches, etc. A series of laboratory exercises illustrating certain part of plant and animal biology follow.
Part II is taken up with suggestions as to the microscopical ex- amination of some 35 “drugs” in their commercial form. In Ap- pendix A is a valuable table defining the various elements consti- tuting and produced by cells, giving their properties and the meth- od of identifying them by staining or otherwise.
The last 50 pages of the book are given to figures illustrating lenses, microscopes, drawing apparatus, tissues, organs, drugs.
Mechanically the book is marred by the unnecessarily large type in which the words desired to be emphasized are printed.
Microscopy and the Microscopical Examination of Drugs, by Charles E. Gabel, Ph.D., Microscopical Food and Drug Analyst Iowa State Dairy and Food Commission. Illustrated; 114 pages. Price $1.00, postpaid. Des Moines, Iowa.
NECROLOGY
Announcement of the death of the following members of the American Microscopical Society has been received since the issue of the last number:
A. E. Aubert, ’12, New York City.
Geo. C. Crandall, M.D., ’04, St. Louis, Mo.
J. D. Hyatt, Past President and Honorary Member, New Ro- chelle, N. Y.
AMERICAN MICROSCOPICAL SOCIETY 85
PROCEEDINGS
of the American Microscopical Society MINUTES OF THE CLEVELAND MEETING
The Society was called to order by President F. D. Heald in the Biologi- cal Laboratory of the Western Reserve University, Cleveland, Ohio, at 3:30 p. m., Jan. I, 1913.
The reports for 1912 of the Custodian and Treasurer were read and ordered referred to an auditing committee. This committee was later named by the President, consisting of Professor Frank Smith and Mr. J. E. Ackert, both of Urbana, Illinois.
Due to the fact that only one business session was provided for, it was unanimously agreed to suspend By-laws V and VI, and to nominate officers from the floor. The following officers were nominated and elected for 1913:
President: Professor F. Creighton Wellman, School of Tropical Medi- cine, Hygiene and Preventive Medicine; Tulane University, New Orleans, La.
First Vice President: Professor F. C. Waite, Medical Dept., Western Reserve University, Cleveland, Ohio.
Second Vice President: Professor H. E. Jordan, University of Virginia, University, Va.
Treasurer (3 years): Professor T. L. Hankinson, Eastern Illinois Nor- mal School, Charleston, IIl.
Elective Members Executive Committee: Dr. H. L. Shantz, Bureau Plant Industry, Washington, D. C.; Professor J. W. Scott, Kansas Agricul- tural College, Manhattan, Kansas; Professor George E. Coghill, Denison University, Granville, Ohio.
Members of the Council of the A. A. A. S.: Professor F. D. Barker, University of Nebraska, Lincoln, Nebraska; Professor A. M. Reese, Uni- versity of West Virginia, Morgantown, W. Va.
An informal discussion, without vote, was had concerning the utilization of the Spencer-Tolles Fund for research, and other items of general policy.
The verification and publication of the Minutes were left in the hands of the President and Secretary.
86 AMERICAN MICROSCOPICAL SOCIETY
CUSTODIAN’S REPORT FOR YEAR 1912
SPENCER-TOLLES FUND
Reported at) Wadshineton Mecting oe hi iosc es vcs yes nash dane sehn ies $3,352.16
Dividends teceived Muring: Veat AO lee et kiiotese\er ois sstere bislela eM aie eeite ne 203.28
SNE EMER) ome ioncis We wines © eke Wate ew aie AER oboe inate: ce pis See atures ewer 4.00
$3,559.44
Less ‘dues paid for Lifte-members.: . 2002 eee ed RE SRY 8.00 Total WvVEsted eres: < kM eee eee aa ate tale Melons le saidee aia abeeles $3,551.44 het unchease ‘dariny years. 2.8. kOe ARUP ea $ 199.28 Grand Totals:
All:contributionsetondater: sic. cc cince cuise tee wtoe s cies Oeisaee $ 700.27
Pill Saleeas TOTOCCERINGS. . ose h sno cc vane ce seb cree cewar's 625.73
PATA EIEIO SHINS CP eS ok sein lpictcas vet ee ccs see bea siemet 250.00
Pill COPE AIA GIVIGENGS 7 cose acc heats ces ese teateak pee 2,115.44 $3,601.44 Less:
AIDS, eek as 5 Sie 64nd smiks cok creole Mee $ 100.00
AG Hite-menberchip 1aues: Sols Ss. cad. cae we eter dese wretts 40.00 $ 140.00 INGENDalanlce tales yc at's site BOTS eee ee el cercheet ete els $3,551.44
Life-members and Contributors of $50 and over: John Aspinwall, Rob- ert Brown, (deceased), J. Stanford Brown, Henry B. Duncanson, A. H. Elliott, John Hately, Iron City Microscopical Society, and Troy Scientific Association. : Macnus Priaum, Custodian.
We the undersigned committee hereby certify that we have carefully examined the foregoing account, compared it with vouchers and found the same correct. ,
FRANK SMITH, J. E. Ackert, Auditing Committee.
a ays.
To To To To To To To To To To To To To
AMERICAN MICROSCOPICAL SOCIETY 87
ANNUAL REPORT OF TREASURER OF AMERICAN MICROSCOPICAL SOCIETY
December 21st, 1911 to December 26th, 1912.
RECEIPTS
palance: onsbandyiromelOUrceysincics «slew selceeieie, oo eos oe) moniveleiee $ 67.49 CME SHOMMOMMG THEM DES las crlon (alae ievciorers: 10 oreo etateroie ciciar ciel ns avoaveneraterarons 340.66 GUESMOR HME WIM INEMIDELS he ctarairs oie icc ere sve ies Kovatlcietciens cb 36 oa arcnrneodions 110.00 PETAL ETN Bate SCOR ACE ODE ISO OCR EOS COREE EEE thane 165.00 SUDSEHIP tions) Lobe VOlINTEm aT e eras Sanaa ere a ace cattle alent eotatele 17.00 SERIO EIGIIS) TOR, VOMNNE! S2 0a eee da cf acarcicw decane as vate aseaiee es 2.00 subscribers for volumes other than 31 and 32................-.. Y4.00 sales of misc. numbers of Transactions to those not subscribers. . 38.00 SoeNOLISCIOMmOranSaActONns.)... areca eae aclo aoe ee sion 70.00 BOMETLISEES) 111: VOLE 20) ATG 30). cronsrera() ca ciavpera od ot aise: etnies eralaids 70.00 PRESSOR Si: 11) VONUIMIG™ AE Ia bo ict pucrereik nie dao hate ons ore, aslo dae ewe 87.40 Enver eaberts 10F GONAVOMs «.c506 20 ceeded << Se iailvateth tu geees eeersts 125.00 PEMA PALO OSE) CHICE Coca. said sn te 3 © os nrcrel alors camateyonare ates 48.31 BRERA Pine Acts Sotares chins Sicebartt tan erree onlin wieln a sia, ank Na. chai owes Calas oe ee $1,234.86
EXPENDITURES
printing of Transactions, volume 31, numbers I, 2, and 3........ $ 550.53 engraving plates for Transactions, volume 31.................-: 143.47 purchasing back numbers of Transactions to complete sets...... 8.00 Bostate and Express, OF) SeCCretab ys inc <a Se veld odds een whee 68.93 SAINELOTtNe: UreASUnens icc ecm see ee tie as aaa ee ee sees 15.61 office expenses of Secretary, stationery, stenography, etc......... 71.99 RAMMELOLeCPECASULEE ssc aes eer there Te Te ee eae ee te ae 17.44 traveling expenses of Secretary and Treasurer, necessitated by committee meetings at Bloomington and Urbana, Ill............. 12.20 Secretary’s expenses at the Washington meeting in IQII......... 25.00 = SELES ope A gn Rae ic hs 28 ont a At te payee 50.66 CMG EMTIOOIGES So ol oa a!e chain des ath wala einige vw \ale die ats sizisihieer ers 3.45 al aticeMonalanlants,< 5 cto) caret stoke era eee eee ee 267.58 PG RAM REA ad, o a's) sical a eis alae ame ee aie wwe & waverseere maemo $1,234.86
Signed, T. L. HANKINsSoN, Treasurer.
Examined and found to correspond with books and vouchers. FRANK SMITH, J. E. Acxert, Auditing Committee.
TRANSACTIONS
OF THE
American Microscopical Society
ORGANIZED 1878 INCORPORATED I89Q1
PUBLISHED QUARTERLY
BY THE SOCIETY
EDITED BY THE SECRETARY
VOLUME XXXII
NuMBER Two
Entered as Second-class Matter December 12, 1910, at the Postoffice at Decatur, Illi- nois, under act of March 3, 1879.
Decatur, ILL. Review PriInTING & STATIONERY Co. 1913
OFFICERS.
President: F. CREIGHTON WELLMAN, M. D................ New Orleans, La. Mist Vice President: F.C. Waite, PHD. boc. i cos eee sien Cleveland, Ohio Second Vice President: H.E. Jorpan, Ph.D............. Charlottesville, Va. pecretarvie Le We GAREOQWAY 2 otic ciejeicnisit nie ciedla de ae etnlalel lee ede Decatur, Ill. EF CRSUrey 1), La 1 EUANIKUN SONI ae ciclo acitnn 4s ee esis els sieteeeier Charleston, Ill. Cectoutan.’ “NIAGNOUS: PREATINE loi. .5'40 o's ies Gasica a bid Ode rece Meadville, Pa.
ELECTIVE MEMBERS OF THE EXECUTIVE COMMITTEE
| WALES 0 6 Ae Bureau Plant Industry, Washington, D. C. MENA SENET 49) rcfa Merah 2 abe cence Mer daieiabinae |” w cea cto etal a Leigh ols Manhattan, Kans. Seta MINI Ea ce ects aia, ois eA eal wa tialne se G.8 sie,s oes omak led Granville, Ohio
EX-OFFICIO MEMBERS OF THE EXECUTIVE COMMITTEE Past Presidents still retaining membership in the Society
R. H. Warp, M.D., F.R.M.S., of Troy, N. Y,, at Indianapolis, Ind., 1878, and at Buffalo, N. Y., 1879 Apert McCa tra, Ph.D., of Chicago, II. at Chicago, Ill. 1883 T. J. Burrmt, Ph.D., of Urbana, III., at Chautauqua, N. Y., 1886, and at Buffalo, N. Y., 1904. Gro. E. Fett, M.D., F.R.M.S., of Buffalo, N. Y., at Detroit, Mich., r89o. Stmon Henry Gace, B.S., of Ithaca, N. Y., at Ithaca, N. Y., 1895 and 1906 A. Ciirrorp Mercer, M.D., F.R.M.S., of Syracuse, N. Y., at Pittsburg, Pa., 1896. A. M. Bree, M.D., of Columbus, Ohio, at New York City, 1900. C. H. E1icENMANN, Ph.D., of Bloomington, Ind., at Denver, Colo., rgor. Cuartes E. Bessey, LL.D., of Lincoln, Neb.,
E. A. Birce, LL.D., of Madison, Wis., Henry B. Warp, A.M., Ph.D., of Urbana, IIL,
at Pittsburg, Pa., 1902. at Winona Lake, Ind., 1903.
at Sandusky, Ohio, 1905. Hersert Oszorn, M.S., of Columbus, Ohio,
at Minneapolis, Minn., 1910. A. E. Herrzzer, M.D., of Kansas City, Mo., at Washington, D. C., 1911. F. D. Heatp, Ph.D., of Philadelphia, Pa., at Cleveland, Ohio, 1912.
The Society does not hold itself responsible for the opinions expressed by members in its published Transactions unless endorsed by special vote.
TABLE OF CONTENTS
FOR VOLUME XXXII, Number 2, April, 1913
Notes on Japanese Protozoa, with Plate III, by C. H. Edmondson and
TER MEU SINRNTST SRT LIMP CY wie’ s nba Sic cise cinta Pemiah ie alee mer eet Aloha. bieasbeatcty elk een 93 Experimental Amitosis in Onion Root Tip, by H. E. Jordan............. 103 Summaries in Micro-biology: The Black Moulds (Mucoracee), with
I JSS Wasa CAN AVR vac Payee santo Grace sducic icky lo vere iaccle ett eee bin stale seta ales Siebel meherntete 113
Notes and Reviews: Summary of the Elements in the Reproductive Process (Plate VI), by T. W. Galloway; The Growth of the Com- pound Eye (Plates VII and VIII), by E. W. Roberts; Fresh-water Hydroids, by Edward Potts; Mutation in Micro-organisms; Differ- entiation in Chromosomes; Bud-formation in Syllids; Cork Oak in Portugal; A Simple Method to Remove Paraffin Sections Which are Stuck to a Sheet of Paper or to the Hand; To Kill Mosquitos or Other Insects; To Keep Slides at Constant Temperature; Section- cutting in Gelatin by Freezing; Household Bacteriology............ 127
PEG OUAEETA [AE TS Ptae ee e ie ron ais wl din Jo nos a a sees stew we Ome Rat ialele ys Ot ie 159
TRANSACTIONS
OF
American Microscopical Society
(Published in Quarterly Installments)
Vol. XXXII : APRIL, 1913 No. 2
NOTES ON JAPANESE PROTOZOA WITH FIGURES AND DESCRIPTIONS OF NEW AND RARE SPECIES
C. H. EpMoNDSON AND R. H. KinGMAN
The fresh-waters of Japan afford a wonderful opportunity for the enthusiastic microscopist. Conditions under which simple or- ganisms thrive are not wanting anywhere in that country. Flooded rice fields of the lowlands, cool mountain streams and innumerable lakes, large and small, are teeming with low plant and animal forms.
To what extent systematic study of the microscopic fauna and flora of the waters of Japan has progressed, under the direction of the eminent biologists of that country, the writers of this article are not able to state.
With a view of determining the species of Protozoa characteris- tic of Japan and comparing them with the American forms, micro- scopic studies were carried on by C. H. Edmondson during July and August, I912, in various parts of the main island. Beginning with Kobe, observations were made through the central and eastern sec- tions of the country and as far north as Lake Chuzenji.
Material was gathered from rice fields, small pools, streams and lakes. Collections were made from the following large lakes: Lake Biwi, altitude above sea level 328 ft.; Lake Hakone, altitude 2,378 ft.; Lake Chuzenji, altitude 4,375 ft. Since the survey covered a wide territory with considerable variation in local conditions as well as in altitude, the list of species embodied in this brief report may well represent the characteristic unicellular fauna of the entire country. The portion of this article concerned with Rhizopoda is largely a result of the work of R. H. Kingman, a student of zoology,
O4 EDMONDSON AND KINGMAN
who identified and studied many forms from preserved material. By comparing the list which follows with numerous local records of observers in America and other parts of the world one sees some added evidence of the wide distribution of many species of Protozoa.
The accompanying figures, prepared by Mr. Kingman from permanent mounts, represent new, or rare species of Rhibopods or forms showing considerable variation.
Phylum PROTOZOA: Subphylum SARCODINA: Class RHIZOPODA Subclass AMOEBEA
Order GyMNOMOEBIDA Family Amoebidae Amoeba Ehrenberg. <A. proteus Leidy; A. guttula Duj.; A. Sphaeronucleus Greef; A. striata Penard; A. radiosa Ehr.; A. saphrina Penard.
The species of this genus were not common in any locality. Material from Myoho-in Temple grounds, Kyoto, furnished the best examples. Large individuals of A. radiosa were taken from Lake Hakone.
Hyalodiscus Hertwig and Lesser. H. rubicundus H. and L.
3ut one individual was observed. A very typical form, red- dish-brown in color. From a rice field, Kyoto.
Arcella Ehrenberg. A. vulgaris Ehr.; A. discoides Ehr.; A. costata Ehr. ; A. arenaria Greef.
Of the above species A. vulgaris is the more widely distributed in Japan. Lake Chuzenji and the region of Kyoto furnished the best material. |
Centropyxis Stein. C. aculeata Stein.
Found in all localities. Very abundant in Lake Hakone. Great variation in size occurs in this species and some very large forms were observed.
Pixidicula Ehrenberg. P. cymbalum Penard.
A species rarely observed. Found in material from Lake Hakone.
Lecquereusia Schlumberger. L. spiralis Ehr.; L. modesta Rhumbler.
These two speices are widely distributed in Japan, the former being much more abundant. In the typical L. spiralis the aperture
JAPANESE PROTOZOA 95
is usualy directed obliquely toward one side with a prominent hump at the outer base of the neck. In the common form in Japan the aperture is directed almost straight forward, in very rare cases there being a slight prominence at the base of the neck. Common in Lake Hakone. Typical examples of L. modesta were found in lakes on Mt. Rokkozan.
L. epistomium Penard, a common species of the high lakes of Colorado, was not observed in Japan.
Difflugia Leclerc. D. pyrifornus Perty; D. lobostoma Leidy; D. constricta Leidy; D. acuminata Ehr.; D. tuberculata Wallich; D. lebes Penard; D. bacillariarum Perty; D. elegans Penard.
Of the species of Difflugia in Japan, D. elegans is apparently the most common. It is widely distributed and shows a great range of variation. D.Jebes, not uncommon in some of the lakes of Colorado, was observed but onee, in material from the bottom of Lake Hakone.
Pontigulasia Rhumbler. P. spectabilis Penard.
But one individual observed: From Lake Hakone. A very typical form.
Quadrulella Cockerell. Q. symmetrica Schultze; Q. symmetrica var. curvata Wailes.
Very typical forms of the species were taken from shallow lakes on Mt. Rokkozan. The variety, observed but once, was found in Lake Hakone.
Nebela Leidy. N. collaris Leidy; N. crenulata Penard; N. hippo- crepis Leidy; N. triangulata Lang.
In the material collected in Japan species of Nebela were very rare.
There can be no reason to believe, however, that the genus is not well represented in that country. One individual of the rare species, N. hippocrepis, was found in material from Mt. Rokko- zan. In the ooze from the rocks along the shore of Lake Hakone and from the border of a shallow lake on Mt. Rokkozan was found a species which is here listed under the name JN. triangulata Lang.
The Japan species resembles, in some particulars, Nebela bipes Carter, as described in Clare Island Survey, Part 65, by Wailes
96 EDMONDSON AND KINGMAN
and Penard, and may represent an intermediate form between N. triangulata and N. bipes.
In the Japan form the shell is very transparent, compressed, irregular in outline with the fundus region inflated in an asymmet- rical manner. The aperture is slightly oval.
Great variation exists in the form of the shell and in the arrangement of the plates. In some the plates are circular or oval, distinctly separated from each other with the ground sub- stance of the shell intervening. In others the plates are closely crowded together and very irregular in outline, while in some the plates are regular in outline but distinctly overlap each other.
The irregular inflation of the fundus is a characteristic feature. Usually the posterior lateral borders are expanded into lobes of variable size. In some these prolongations are pointed as in N. bipes, but more often they are blunt or rounded. Occasionally the fundus is truncated posteriorly, sometimes it is strongly con- cave. The extensions of the fundus are seldom uniform on the two sides of the shell and are never the same in two individuals. Usually the narrow view of the shell presents an irregular outline. The compression of the shell is seldom uniform, but is always stronger at the fundus border.
The size of the Japanese form ranges from 80 to 100m in length, including the prolongations of the fundus; from 60 to 80p in breadth of fundus and from 28 to 60n in the long diameter of the aperture.
No living individuals were observed.
Heleopera Leidy. H. picta Leidy.
Material from Mt. Rokkozan furnished the only species of the genus observed. Under high power the plates are seen to be circular, slightly overlapping. Little foreign material is attached to the shell.
Phryganella Penard. P. hemisphaerica Penard. Frequently observed in many localities. Campascus Leidy. C. dentatus, sp. nov.
In 1877 Leidy discovered Campascus cornutus in China Lake, Wyoming, at an altitude of 10,000 feet. Apparently the species has not been observed since that time.
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JAPANESE PROTOZOA 97
More recently Penard described two species of the genus, Campascus triqueter and Campascus minutus, from the deep lakes of Switzerland. In both species described by Penard the fundus is without the horn-like prolongations of the form ob- served by Leidy. Campascus minutus was reported by Wailes in 1912 from the New York water-supply drawn from Croton Lake Reservoir.
The form under consideration, which is apparently a new species, was found in the ooze taken from the rocks along the shore of Lake Hakone, Japan, in August, 1912.
The description follows: Shell of yellowish, chitinoid material similar in general outline to Campascus cornutus. Under high power the shell has the appearance of being distinctly punctate. In some individuals the punctae are arranged in a regular diagonal manner, in others there is no regularity about the arrangement. In no specimens examined can outlines of plates be detected even with the oil immersion lens.
The neck is short and sharply bent, nearly at right angles to the long axis of the shell. The circular aperture is bordered by a thin delicate membrane of approximately 4» in breadth.
A number of short, blunt, tooth-like prolongations are present on the posterior border of the fundus. From three to seven of these processes are usually present. They vary in size and when numerous give an irregular, crenulated appearance to the posterior edge of the fundus, when the broad side of the shell is viewed.
In Leidy’s species the two horns are directed laterally and pos- teriorly, their tips not projecting beyond the posterior border, giving the fundus a rounded outline when the narrow side of the shell is observed. In this species the teeth-like points are directed backward and project beyond the border, giving the fundus the appearance of terminating in a spine when the narrow side of the shell is seen.
Leidy records the size of Campascus cornutus as ranging from 0.112 mm. to 0.14 mm. long by 0.18 mm. broad.
This species of Japan is much smaller. The length of the shell, including the spines and the collar about the aperture, ranges from 60 to 80n. Breadth of fundus from 50 to G6y.
98 EDMONDSON AND KINGMAN
Greatest thickness, narrow view, 284. Aperture 12 in diameter.
The living organism was not observed. Paulinella Lauterborn. P. chromatophora Lauterborn.
Empty shells of this very minute form were found in material from the bottom of Lake Hakone and also from shallow lakes on Mt. Rokkozan. The shell is composed of five longitudinal rows of plates and possesses a short neck. The Japan form is very typical.
Cyphoderia Schlumberger. C. ampulla Ehr.; C. ampulla var. papil- lata Wailes.
The species is very common in Lake Hakone and was found in other localities. Considerable variation in size and also in the arrangement of plates occurs. The plates are usually placed in diagonal rows, but this regularity is not always maintained.
The variety was observed but once and that in material from Lake Hakone.
Sphenoderia Schlumberger. S. lenta Schiumb.
Very widely distributed and also very common in Japan. The only species of the genus to be determined.
Euglypha Dujardin. £. alveolata Duj.; E. brachiata Leidy; E. filifera Penard; E. laevis Perty; E. ciliata Ehr.; E. armata Wailes.
A few species of this genus are very abundant in Lake Hakone as well as in other localities. Two species, E. filifera and E. ciliata, were rarely observed, the others mentioned are common.
Assulina Ehrenberg. A. seminulum Ehr.
Observed in material from Kyoto. A very typical form, choco- late-brown in color.
Plagiopyxis Penard. P. callida Penard.
Indentified in material from Kyoto. Not common.
Trinema Dujardin. T. enchelys Ehr.; T. lineare Penard; T. cam-
planatum Penard.
The genus represented by T. enchelys is very common in many localities. The other two species were rarely observed.
. ——— ———< =.
JAPANESE PROTOZOA 99
Class ACTINOPODA Subclass HELIOZOA Order APHROTHORACIDA
Actinophrys Ehrenberg. A. sol Ehr.
Observed in great abundance at Kyoto; rarely seen in other localities.
The following list is a record of the species of Mastigophora and Infusoria identified in material taken from the fresh waters of Japan. Flagellates and ciliates are very abundant in that country, as elsewhere, and the small number of species here listed indicates brevity of observation rather than any dearth in pro- tozoan fauna. The remarkable thing to be noticed is the identity of the Japanese forms with our common American species.
Subphylum MASTIGOPHORA: Class ZOOMASTIGOPHORA
Order HETEROMASTIGOPHORA
Notosolenus Stokes. A’. orbicularis Stokes. Anisonema Dujardin. A. acinus Duj. Order Monapipa Anthophysa Bory d. St. Vincent. A. vegetans Mill. Order EUGLENIDA Euglena Ehrenberg. F. viridis Ehr.; E. deses Ehr.; E. acus Ehr. Phacus Dujardin. P. pleuronectes Mill.; P. longicaudus Ehr. Trachelomonas Ehrenberg. T. hispida Stein; T. volvocina Ehr.; T. armata Stein. Astasia Ehrenberg. A. trichophora Ehr. Distigma Ehrenberg. D. proteus Ehr.
Subphylum INFUSORIA: Class CILIATA Order HoLorricHIDA Coleps Ehrenberg. C. hirtus Ehr. Lacrymaria Ehrenberg. L. olor Mill.
Lionotus Wrzesniowski. L. fasciola Ehr. Dileptus Dujardin. D. gigas C. and L.
100 EDMONDSON AND KINGMAN
Chilodon Ehrenberg. C. cucullulus Mill.
Nassula Ehrenberg. N. oronata Ehr.
Loxocephalus Ehrenberg. L. granulosus Kent. Cinetochilum Perty. C. margaritaceum Ehr.
Frontonia Ehrenberg. F. leucas Ehr.
Paramaecium Miiller. P. caudatum Ehr.; P. bursaria Ehr. Cyclidium Ehrenberg. C. glaucoma Ehr.
Pleuronema Dujardin. P. sp. (undetermined).
Order HETEROTRICHIDA
Spirostomum Ehrenberg. S. ambiguum Ehr. Stentor Oken. S. caeruleus Ehr.; S. polymorphus Ehr. Gyrocoris Stein. G. oxyura Stein.
Order HypotricHIDA
Oxytricha Ehrenberg. O. pellionella Mill. Stylonychia Ehrenberg. S. notophora Stokes. Euplotes Ehrenberg. E. charon Mull. Aspidisca Ehrenberg. A. costata Duj.
Order PERITRICHIDA
Vorticella Linnaeus. V. sps. A number of undetermined species were observed. Cothurnia Ehrenberg. C. sp. (undetermined).
Class SUCTORIA
Sphaerophrya Claperéde and Lachmann. S. magna Maupas. Washburn College, Topeka, Kansas.
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102 EDMONDSON AND KINGMAN
EXPLANATION OF FIGURES
Pirate Il
Fig. 1, Lecquereusia spiralis Ehrenberg; X 272. From Lake Hakone. Fig. 2, Lecquereusia spiralis Ehrenberg; X 257. From Lake Hakone. Fig. 3, Lecquereusia spiralis Ehrenberg; 272. From Lake Hakone. Variations of the species common in Japan. The aperature is directed almost straight. Fig. 4, Lequereusia modesta Rhumbler; X 225. From Lake Chuzenji. Fig. 5, Difflugia bacillariarum Perty; X 225. From Lake Hakone. Fig. 6, Difflugia elegans Penard; X 195. Very common. Individuals observed ranged from 60-194” in length. Fig. 7, Quadrulella symmetrica var. curvata Wailes; X 427. Near the aperture the plates become small and irregular. Rarely ob- served. From Mt. Rokkozan. Fig. 8, Nebela hippocrepis Leidy; X 108. Broad view of a shell. From Mt. Rokkozan. Fig. 9, Nebela hippocrepis Leidy; X 198. Narrow view of same. Fig. 10, Nebela triangulata Lang; X 325. Broad view of a shell. From Lake Hakone. Fig. 11, Nebela triangulata Lang; X 378. From Lake Hakone. Fig. 12, Nebela triangulata Lang; X 354. From Lake Hakone. Fig. 13, Nebela triangulata Lang; X 315. From Lake Hakone. Fig. 14, Nebela triangulata Lang; X 325. Narrow view of a shell. From Lake Hakone. Variation in the shape of the fundus and in the arrangement of the plates shown in these figures. Fig. 15, Campascus dentatus, sp. nov.; X 370. Broad view of a shell with the posterior border of the fundus provided with numerous teeth-like prolongations. From Lake Hakone. Fig. 16, Campascus dentatus, sp. nov.; X 390. Broad view of another shell. From Lake Hakone. Fig. 17, Campascus dentatus, sp. nov.; X 390. Broad view of another shell. From Lake Hakone. Fig. 18, Campascus dentatus, sp. nov.; X 390. Narrow view of same. From Lake Hakone.
2 2
Fig. 19, Paulinella chromatophora Lauterborn; X 1050. From Lake Hakone.
apanese Protozoa
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Pirate IIT.
102
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EXPERIMENTAL AMITOSIS IN ONION ROOT TIP H. E. Jorpan
INTRODUCTION
My recent study of amitosis in the lining epithelium of the epididymis of the mouse,’ and in certain other ciliated epithelia, led me to the tentative conclusion that the fundamental causative factor here involved is the partition and consequent destruction of the centrosome in the formation of “basal granules” from which the cilia grow. The suggestion was made that direct cell division is proximally related to factors inducing loss of integrity or im- pairment of function of the centrosome. Such factors are vari- ous, including those originally and recently sugested, namely, in- tense secretory activity, and disturbed metabolic conditions charac- terized as “degenerative” (Flemming,? Ziegler? vom Rath,* et cetera), lack of adequate nutriment (Child,® Patterson®), insufh- cient supply of oxygen (Wieman’).
To test experimentally this hypothesis a series of experiments were made by growing onion roots in water to which ether was added. Two assumptions, apparently legitimate, are involved: 1) the onion cell has an analogue (indiscernible) of the centrosome of animal cells, similarly concerned in the formation of the mitotic spindle; 2) ether, and other anesthetics, may be expected to produce a “stupefying’ effect upon the “dynamic center” of the cell thus enforcing a direct method of actual multiplication.
The sole result claimed for the investigation is the fact that onion roots continue to grow vigorously in water to which small quantities of ether are added, and that many of the cells are in various phases of undoubted direct division. No originality is claimed either for the hypothesis or for the experimental procedure. I believe, however, that the facts adduced from the study of the epididymis of the mouse offer the strongest histologic evidence yet reported in support of the hypothesis. The experiments were under-
104 H. E. JORDAN
taken simply to test this hypothesis. The same idea must have suggested the experiments of Pfeffer and Nathansohm ® with spiro- gyta grown in water with ether, and of Wasielewski® with Vicia faba roots grown in chloral hydrate solution.
Nathansohm (1900) claims to have induced amitosis in spiro- gyra and the desmid closterium by transferring karyokinetically dividing filaments to a 1% solution of ether in water. Roots of Phaseolus, Lupinus, Phalaria and Marsilia were similarly treated, but without success in changing cell-division from the indirect to the direct method. Treatment of growing roots of Vicia faba with a 0.7% chloral hydrate solution for various periods is claimed by Wasielewski (1902-1904) to change the majority of cell divisions from mitotic to amitotic. Némec?® (1904), however, interprets the cell pictures. (in roots of Vicia faba, Allium cepa and Pisum sativum, treated with 0.75% chloral hydrate solution) in terms of nuclear fusions, and disputes their amitotic significance. My ex- periments with onion root tip grown in ether solution, on the con- trary, show unmistakable amitosis. However, in view of the fact that the roots grew vigorously, and that mitoses are always exceedingly rare, and in several instances totally lacking, indisputable healthy amitotic divisions (i. e., apparenty non-degenerative) are unexpectedly relatively rare. 7
DESCRIPTION OF THE EXPERIMENTS
The procedure was simply to place an onion, with stem and roots either absent or just appearing, into the mouth of a small jar so selected for size that the root pole of the bulb was immersed in the solution to a depth of about half an inch. The experiments with controls consisted of three series, with summarized results as follows:
First Series
a) Bulb in 4% alcohol solution—Neither stem nor roots appeared.
b) Bulb in water unchanged for four days.—Both stem and roots appeared. Of 5 roots examined, two were disintegrating; the remainder showed occasional mitoses in the plerome cells and several doubtful instances of degenerative amitoses in the pleriblem cells.
Ae
a)
EXPERIMENTAL AMITOSIS 105
Bulb in water to which a few drops of ether were added thrice daily for two days.—Stem barely developed, many vigorously growing roots appeared. Of 6 roots examined only two showed mitotic figures, limited to the plerome; and all showed occa- sional direct divisions among the periblem cells.
Second Series (three to eight tips each) Bulb with roots just showing; in water from 10 o’clock A. M. to 4.30 P. M.—Normal; many mitoses both in plerome and periblem; also a few in dermatogen. Bulb in water, unchanged for 4 days.—Mitoses still frequent ; a few tips distintegrating. Bulb in water changed twice daily for 4 days——Normal; nu- merous mitoses. Bulb in moist cotton 1 day.—Tips of young development; neither mitoses nor amitoses. Bulb in moist cotton 2 days.—Distintegrated. Bulb in water unchanged for one week.—Normal; many mitotic figures. Bulb in water + ether, changed twice daily for 1 day.—Neither mitoses nor amitoses. Bulb in water + ether, changed twice daily for 3 days—No mitoses; many amitoses. Bulb grown in cotton moistened with water and ether for 4 days.—No growth of either stem or roots.
Third Experiment Bulb in water to which a small amount of ether was added three times daily for 5 days, and allowed to remain in the un- changed water for 2 days longer.—Normal; numerous mitotic figures. The roots were fixed in Flemming’s strong solution. The sections were cut at from 5 to 10 microns, and stained in
iron hematoxylin, with and without eosin counterstain.
Description of Normal Root A brief description of normal conditions seems desirable before
proceeding to an analysis of the experimental results of the several
106 H. E. JORDAN
series. The description is based upon an excellent preparation previously made and used for demonstrating mitotic figures in class- room work.
The root-tip contains characteristic cells in the several regions: dermatogen, periblem, plerome, and root-cap. The dermatogen con- sists of from 2 to 5 layers of very long rectangular cells, with the longest axis parallel to the long axis of the root. The nucleus is pale and finely granular, with one or several nucleoli. The cyto plasm contains large vacuoles and numerous dcep-staining spherical granules of various sizes (mitochondria). Some of the cells are in process of indirect division.
The periblem consists of from 7 to Io rows of small rectangular cells surrounding the central plerome. The longest axis of these cells is generally perpendicular to that of the dermatogen cells. The nuclei are pale staining, finely granular or delicately reticular, mostly with two nucleoli frequently surrounded by a clear halo. The cytoplasm is considerably vacuolated and contains granules similar to those described for the dermatogen. The cells of the layers, more particularly from the third inward and from just above the upper
- :
Fig. 1. Sketch of periblem cell from normal root showing early process in
constriction of nucleolus. Abundant earlier and later phases also ap- pear. The vacuolated cytoplasm contains deeply staining granules (mito-
chondria). The nucleus is pale-staining, finely granular, or delicately reticular.
Fig. 2. Typical rectangular bi-nucleolate cell of periblem of normal root. One of the nucleoli is surrounded by a clear halo, probably a fixation artefact.
Figs. 3 and 4. Periblem cells from root undergoing early degenerative changes. The cytoplasm contains huge vacuoles, and lacks mitochondria. The nuclear wall is irregular and apparently suffering an equatorial con- striction closely simulating, if not actually, a direct division. Excessive number of nucleoli, i. e., more than two is a common condition in the cells of these tips.
EXPERIMENTAL AMITOSIS 107
limit of the root-cap, show large numbers of nucleoli at all phases of constriction and separation in the process of the formation of binucleolate nuclei (Figs. 1 and 2). The appearance is exactly that of Remak’s classic illustration of the initial step in amitosis. How- ever, the further steps, viz., nuclear and cytoplasmic fission, no- where appear; and mitoses at all phases are very abundant.
The plerome consists of a variable number of layers. The cells are long rectangular, relatively huge rectangular, and approxi- mately square, in shape. The nuclei are large oval or spherical, mostly with deep-staining coarse reticulum, and with one or two chromatic nucleoli, sometimes appearing achromatic. The cytoplasm contains smaller vacuoles than in the periblem and dermatogen cells and relatively fewer mitochondria. Mitoses are most abundant in this portion. Two chromatic nucleoli are frequently present even at the segmenting spireme stage, of irregular oval shape but with sharp contour.
The root-cap contains larger and smaller polyhedral cells with enormous vacuoles in the cytoplasm and very sparse mitochondria, and pale granular nuclei with one or generaly two nucleoli. These cells are only rarely seen in mitosis in this preparation.
The points of special significance in normal root tip for this study are: 1) absence of amitoses; 2) great abundance of mitoses, especialy in plerome; 3) nucleolar constriction in, and binucleolate character of, the periblem cells ; 4) presence of mitochondrial gran- ules (an index of virility); and 5) general pale-staining, finely granular, character of the periblem nuclei.
ANALYSIS OF THE First SERIES OF EXPERIMENTS
The non-appearance of roots or stem on the bulb in the 4% solution of alcohol is interpreted to mean that this solution was too strong to permit development. Since the experiment was not repeated with weaker solutions the interpretation must be tentative ; but since this is the only complete failure of development in the several series (save one with bulb in cotton moistened with ether solution) it is very plausible. The reason for not further experi- menting with alcoholic solutions at this time was the fact that posi- tive results were obtained with the ether solutions.
108 H. E, JORDAN
The roots of the bulb grown in water unchanged for four days differed somewhat from normal, and several were in the later stages of disintegration. Mitoses are numerous in the plerome cells, but practically absent in the periblem cells. Mitochondrial granules are relatively sparse and pale-staining. Relatively more cells have two nucleoli; a number have three (Fig. 3) and even four nucleoli. The periblem nuclei are frequently irregular in outline, with numer- ous blunt processes; a few may possibly be in process of amitosis (Figs. 3 and 4). On this bulb the stem grew very vigorously. Cytologic appearances must probably be interpreted in terms of early degeneration, involving possibly slight amitotic division.
Roots of bulbs grown in a 3% aqueous solution of ether grew very vigorously, while the stem developed but little. This result seemed to indicate a stimulating effect to root formation, causing indirectly a retardation of stem growth. The jar with bulb was covered under a larger jar to prevent excessive volatilization of the ether. When uncovered as in the later experiments this differ- ential growth of roots and stem was not so evident. The roots have a perfectly healthy appearance, in section in all respects like the normal except that mitoses are almost, and in some tips entirely, lacking even in the plerome cells. Amitoses are abundant in the periblem cells (Figs. 5 and 6), usually appearing in groups of four or eight. Many of these nuclei have an irregular contour with short pseudopodial processes like in the foregoing set of roots. Only rarely can the final process of the formation of a wall between the
Fig. 5. Periblem cell from root grown in 3% ether solution (first set of ex- periments), showing early stage in amitotic division.
Fig. 6. Similar cell, showing a later phase of direct division, including the formation of a new cell membrane between the separating daughter nuclei. The cytoplasm contains large vacuoles and lacks mitochondria, in which respects it resembles a degenerating cell.
Fig. 7. Diagram of frequent, type of nucleus showing character of initial phase of nuclear direct division.
EXPERIMENTAL AMITOSIS 10g
amitotic moieties be seen (Fig. 6). Many nuclei show a sharp cut at one point on the surface (diagram, Fig. 7), the initial step in the nuclear constriction. This appearance is practically lacking in the previous set.
The number of bi-nucleolate cells does not seem relatively larger than in the normal or degenerating tips. However, multi- nucleolate cells are absent. No significance can be attached to the bi-nucleolate nuclei, from the standpoint of amitosis, since these are almost equaly abundantly present both in normal and degenerat- ing tips. Still, when followed by nuclear fission, as occasionally in tips grown in ether solution, the nucleolar fission represents the initial step in amitosis.
There remains no question, I believe, that true amitosis occurs in these tips, and as the result of ether in the water; but whether this result is direct (i. e., specific, the ether acting anzsthetically upon the astral system) or indirect (1. e., due to abnormal environ- mental conditions produced by the ether), must remain uncertain. However, the fact that undoubted amitoses are relatively much more abundant in the tips grown in water with ether than the doubtful ones in the unchanged water speaks in favor of a direct retarding influence to centrosomal activity. This conclusion is further strengthened by the fact that the roots grew vigorously; and that no cytologic indications of degeneration, beyond a number of irreg- ular nuclei, appear. The result is disappointing, however, in that the amitoses are unexpectedly rare in view of the rapid growth and the absence of mitoses. It cannot be asserted with full surety that growth was entirely by amitosis, since a few mitoses appear in the plerome cells; and, moreover, the possibility remains that the tips were cut at the interval between mitotic waves. But if this were the true explanation of the absence of mitoses, not all of the roots would be expected to show substantially the same condition. It seems then that amitosis plays a considerable part in the growth of root tips in water with ether, and that it does not necessarily signify degeneration since the tips after two days are still vigorous and normal. That the complete amitotic process is consummated, though the final step is difficult to demonstrate, is further indicated by the complete absence of bi-nucleolate cells.
110 H. E. JORDAN
It seemed possible that the degeneration and incidental prob- able amitosis of the roots grown in unchanged water might be due to the presence of the extract of onion held by the water; also, this method of sprouting bulbs is so far from normal that only degeneration phenomena (including amitosis) could perhaps be expected. To check these uncertainties, and to further test the influence of ether on mitotic proliferation, the second set of experi- ments was devised.
SECOND SERIES OF EXPERIMENTS
Growth in moist cotton gave wholly negative results as the above summary shows. This evidently makes a most unfavorable growth medium.
The roots grown in water changed twice daily were normal.
Those grown in unchanged water, even after an entire week, were still vigorous and essentially normal. Thus extract of onion appears to have no inhibitory or deleterious effect, at any rate if allowed to volatilize freely. In the previous experiment the bulb fitted more closely into the mouth of the jar. The cause of the degeneration in several roots in the first series of experiments remains obscure.
,9and 10. Periblem cells from roots grown in ether solution (second set of experiments), showing three stages in the nuclear constriction; in Fig. ro a new cell membrane is forming and has progressed into the depth of the constriction on the right.
Figs. 11 and 12. Periblem cells from the same set showing initial and final stages in direct division.