e-ete ee tess ‘eerie Sate St Gree See) : tec : pS TMS lynecesg Pr oe ey Digitized by the Internet Archive In 2010 with funding from University of Toronto http://www.archive.org/details/fungiascomyceteOOgwyn Cambridge Botanical Handbooks Edited by A. C. Sewarp and A. G. Tans.Ley FUNGI ASCOMYCETES, USTILAGINALES, UREDINALES CAMBRIDGE UNIVERSITY PRESS Cc. F. CLAY, MANAGER LONDON : FETTER LANE, E.C. 4 LONDON: H. K. LEWIS AND CO., Ltp., 136, Gower Street, W.C.1 LONDON : WHELDON & WESLEY, Lrp., 28, Essex Street, Strand, W.C. 2 NEW YORK : THE MACMILLAN CO. BOMBAY | CALCUTTA | MACMILLAN AND CO., Lr. MADRAS J TORONTO : THE MACMILLAN CO. OF CANADA, Ltp. TOKYO : MARUZEN-KABUSHIKI-KAISHA ALL RIGHTS RESERVED PALEOMYCES ASTEROXYLI from the Old Red Sandstone, Muir of Rhynie, Aberdeenshire, x 100; after Kidston and Lang FUNGI ASGOMYCETES, USTILAGINALES, UREDINALES By Dame HELEN GWYNNE-VAUGHAN, (FORMERLY H. C. Ii FRASER) DB Re LL. Dy DsSe.76 LS. PROFESSOR OF BOTANY IN THE UNIVERSITY OF LONDON AND HEAD OF THE DEPARTMENT OF BOTANY, BIRKBECK COLLEGE | 702 (si3 ioe CAMBRIDGE AY THE UNIVERSITY PRESS 1922 : | , wv PREEBACE T is impossible to study the Fungi without being impressed by the undiminished value of much of the older work, and especially of that of de Bary, or without recognizing the soundness of his general and very many of his particular conclusions in the light of subsequent investigation. While I have tried to give something approaching adequate references to recent literature, I have thought it superfluous to name the more general works of those earlier authors who are quoted in de Bary’s Comparative Morphology of the Fungi, Mycetozoa and Bacteria and elsewhere. By such investigations the foundations of modern mycology have been laid and their discoveries have passed into the groundwork of our knowledge. The intention of the following pages is to present the fungus as a living individual: the scope is mainly morphological, but, in dealing with objects so minute, morphology passes insensibly into cytology. The introduction deals with fungi in general ; the special part of this volume is limited to the consideration of the Ascomycetes, Ustilaginales and Uredinales. The manuscript was completed early in 1917, but an endeavour has been made to bring it up to date. The majority of the illustrations are drawn from published researches, and I have to thank those authors who have given me permission to copy their figures. Illustrations, the source of which is not stated, are original. In the case of original figures the magnification and the authority for the species are given; this has also been done in other cases whenever the information was available. I am grateful to many past and present students for specimens and information ; to Miss W. Page for figure 112; to Miss H. Tayler for reading proofs; to Mr Charles Dobb for valuable help in the preparation of figures; to Mr E. S. Salmon for advice on the section dealing with specialization of parasitism ; and especially to my friends Miss E. J. Welsford and Mr J. Ramsbottom for assistance in a number of ways. The earlier written parts of the book, and consequently the whole, owe much to the unfailing interest and wise criticism of my husband. H. C. I. GWYNNE-VAUGHAN. LONDON, September, 1921 CONTENTS PAGE INTRODUCTION I - GENERAL ; : I Vegetative Structure I Sexual Reproduction 2 Spores and Spore Mother -cells 3 Accessory Spores 4 Morphology of the ss 4 Classification ; 5 SAPROPHYTISM, PARASITISM AND SYMBIOSIS 6 SAPROPHYTISM 7 Saprophytes on Wood. id Saprophytes on Soil A Coprophilous Fungi : : ; ; 8 Fungi on Fatty Substrata. : ; : 10 Fungi producing Alcoholic Fermentation. 10 Soot Fungi . : ; ; , i2 PARASITISM : : : : : : 13 Facultative Parasites . : : : : ’ 13 Obligate Parasites : : : ; : ; 14 SYMBIOSIS . : : , 16 Endotrophic My een : 16 Exotrophic My ‘corhiza : 18 SPECIALIZATION OF SAPROPHY TISM AND PARASITISM 20 Heteroecism 22 Biological Species 22 REACTIONS TO STIMULI 27 Chemotropism 27 Hydrotropism 29 Aerotropism and Osmotropism 30 Phototropism 30 Phototaxis 31 Formative Influence of Light air Geotropism . 31 maCOMYCETES 34. GENERAL 34 The Ascospores 34 ihe scus 35 The Ascocarp 38 The Paraphyses 38 The Peridium 39 Alternation of Generations . 39 Early Investigators > (©) CONTENTS Cytology. The Fusion in the gens Fertilization Development of the Ascus Meiosis The Third Dipision in ine Acer Chromosome Association The Theory of a Single Nuclear Fusion The Significance of the Fusion in the Ascus Pseudapogamy Spore-Formation Phylogeny PLECTOMYCETES PLECTASCALES Endomycetaceae . Saccharomycetaceae Gymnoascaceae Aspergillaceae Onygenaceae Elaphomycetaceae and Terfeziaceae ERYSIPHALES Erysiphaceae Perisporiaceae Microthyriaceae EXOASCALES Exoascaceae DISCOMYCETES PEZIZALES: = Pyronemaceae Pezizaceae Ascobolaceae Helotiaceae and Mollisiacenc Celidiaceae, Patellariaceae and Cenangiaceae Cyttariaceae HELVELLALES Rhizinaceae . Helvellaceae Geoglossaceae PHACIDIALES Stictaceae Phacidiaceae HYSTERIALES TUBERALES Tuberaceae . CONTENTS a PAGI MOEROINVOCETES 05 =, | 3: . . e EY RQ HYPOCREALES . : : : eile ’ Nectriaceae . ; ; © aA Hypocreaceae : : ; = 146 DOTHIDEALES . ; : : : 2 P52 SPHAERIALES . 5 ; ; ; SP eES3 Chaetomiaceae . : SS Sordariaceae , : 7 SG Sphaeriaceae ; ; 5 a ae Ceratostomataceae : . 159 Amphisphaeriaceae ; . P59 Lophiostomataceae ; : £4 “ROC Mycosphaerellaceae_. ; : : se CO Pleosporaceae. ; ; a, VOI Gnomoniaceae_. ; : ; : TOs Walsaceae.. . : : ; ; : : ; ; 164 Diatrypaceae ' a OS Xylariaceae . ; 2 OS LABOULBENIALES : : : : ; ee ape I PaerOMYCETES . : : ; 7 Asko COMmRA . . Coed, Se ee eer en eS SEE EIDIOMYCETES . . . =... ... 184 USTILAGINALES . : . ; . 184 Ustilaginaceae . : : , a TSS Milletiaceac . , ; : : thecium, x 3403; after Claussen. divides transversely to form a tri- chogyne and an oogonium. The trichogyne usually contains two nuclei, the oogonium five or six and the antheridium about the same number. The nuclei of the trichogyne soon degenerate, and, as observed by Claussen, the wall between this cell and the antheridium is broken down (fig. 60e), so that open communication is established. The male nuclei pass into the oogonium, where for a time ten or twelve nuclei may be counted, then fusion of these in pairs takes place (fig. 60 7). Subsequently the oogonium enlarges somewhat and undergoes septation; large ascogenous hyphae, usually about three in number, bud out from it (fig. 60), and quickly give rise to asci (fig. 60%). Ascus formation is apparently quite typical, the spores are spherical and: have a characteristically sculptured epispore (fig. 602). At 1 Claussen described the cytology of this species under the name of Bouwdiera hypoborea Karst. ; see Cavara, Ann. Myc. iii, 1905, p. 363, and Dangeard, Gotaniste, x, 1907, p- 247, for nomenclature. 102 DISCOMYCETES (cH. about the time of fertilization vegetative filaments begin to grow up (fig. 602), and at last form a loose investment around and among the developing asci (fig. 59). Fig. 60. Ascodesmis nigricans Van Tiegh.; a. 6. c. d. development of the sexual’apparatus; @. and b. X 1000, ¢. x 1100, d. x 800; e. communication between antheridium and trichogyne, x 1300; / -fusion in oogonium, x 1600; g. septate oogonium and ascogenous hypha; antheridium and trichogyne shrivelled, x 1000; 4. uninucleate ascus, x 1100; 7. sculptured spores in ascus, x 750; after Claussen. Pyronema confluens' occurs on burnt ground or on charred and decayed leaves in woods. Its fruits are pink or salmon-coloured, its mycelium to a great extent superficial, and its sexual apparatus of unusually large size. The latter fact led to an early study of its development. It was described by de Bary in 1863, by the brothers Tulasne in 1865 and 1866, by van Tieghem in 1884, and by Kihlman in 1885, and a very clear understanding of the morphology of the sexual organs was reached. A swollen, elongated antheridium was recognized and a more or less globular 1 Pyronema confluens Tul. = P. omphaloides (Bull.) Fuckel. Iv] BEZIZALES 103 oogonium, from which a trichogyne protruded (fig. 61 4). The union of the trichogyne and antheridium was observed and it was shown that from the oogonium ascogenous hyphae subsequently arose. Van Tieghem recorded that the species is very susceptible to external conditions, the antheridium sometimes being reduced in size or absent, though the oogonium nevertheless developed normally and produced ascogenous hyphae. In 1900 appeared the classical researches of Harper, followed in 1903 and 1907 by Dangeard’s, and in 1912 by Claussen’s investi- gations. The mycelium is made up of cells of varying length, regularly multinucleate, containing six to twelve nuclei, and filled with cytoplasm of a loose, spongy structure. The mycelium is sparse and loose, but the reproductive organs are very abundant so that the ascocarps, when mature, are often crowded together. The first indication of sexual reproduction consists in the appearance of thick hyphae, very similar to the corresponding filaments in See an eck oe eee Ascodesmis, and tending, like them, to stand b. mature oogonia and antheridia; at right angles to the substratum. They dicho- peggy eae n tomize (fig. 61a), the terminal cells become swollen, and two types, the more spherical oogonium and the more elongated antheridium, are distinguished ; these arise on separate branches, but from the same mycelium. Both are multinucleate from their initiation. Very soon a slight elevation appears on the oogonium; it elongates rapidly to form the multinucleate trichogyne and, before its growth is complete, is separated from the cogonium by a wall; the trichogyne and antheridium grow towards one another, the tip of the trichogyne meeting sometimes the apex, but more commonly the flank of the male organ. The mature oogonium is a spherical or flask-shaped cell filled with dense cytoplasm and containing many nuclei which are very much larger than those of the ordinary vegetative cells. Its stalk consists of two or three broad cells, its apex is continued into the trichogyne. The nuclei of the latter increase but little in size and are thus much smaller than those of the essential organs at maturity. The nuclei of the antheridium are almost as large as those of the female cell, but its protoplasm is less dense owing perhaps to the absence of accumulated reserve materials. It would appear 104 DISCOMYCETES [ CH. that in both oogonium and antheridium some nuclei degenerate (Claussen). Hyphae from the ascogonial and antheridial branches, and also from the surrounding cells, begin to grow up even before fertilization, and later envelop the sexual organs. When fertilization is about to take place an area of cytoplasm in the region of the antheridium, against the wall of which the tip of the trichogyne is pressed, is differentiated as a very finely granular disc from which the nuclei are withdrawn. Although located in the antheridium this area resembles the receptive spot seen in the oosphere of many algae. The tip of the trichogyne has by this time developed as a beak-like projection, and this also is empty of nuclei and contains dense and finely granular cytoplasm. The walls of the antheridium and trichogyne now break down at the point of contact and a pore is formed. The process is gradual, consisting probably of a softening and solution of the wall material, which seems to Fig. 62. Pyronema confluens; a. antheridium, trichogyne and oogonium, male and female nuclei collected in the middle of the latter; J. c. fusion of male and female nuclei; after Harper. spread out into the cytoplasm of the beak, suggesting that the solvent action 1s mainly exerted from the interior of the trichogyne. The open pore now becomes thickened around its margin so that an exceedingly strong ring unites the antheridium and trichogyne, and they can be bent or turned upon each other without being pulled apart. This arrangement is no doubt necessary to withstand the strain set up by the flow of nuclei from the relatively wide cavity of the antheridium through the narrow pore and beak. Iv] EEZIZALES 105 While the formation of the pore is in progress the nuclei of the tricho- gyne degenerate, and, by the time that they are completely disorganized, a migration of the male nuclei through the pore begins. Ultimately the contents of the trichogyne degenerate still further, till the cytoplasm and nuclei together form a densely staining mass which may be recognized even in the mature fruit. The male nuclei continue to pass into the tube until it is densely filled, and sometimes a trifle swollen. According to most observers the wall at the base of the trichogyne now breaks down so that an open passage is formed and the male nuclei travel through (fig. 63@), and mingle Fig. 63. Pyronenma confiuens; a. entrance of male nuclei into oogonium, x 1435; 4. association of male and female nuclei, x 1160; ¢. ascogenous hyphae with nuclei in pairs, x 820; after Claussen. with the female nuclei. After their migration is complete a fresh wall is laid down across the base of the trichogyne, cutting off the oogonium once more as a single spherical cell. The female nuclei meantime become aggregated together (fig. 62a) and form a hollow sphere or dome or a sickle-shaped group. This is no doubt a provision for insuring their association with the male nuclei with the greatest certainty and dispatch. According to both Harper and Claussen, the sexual nuclei now pair; Harper has recorded complete fusion at this stage (fig. 624), while Claussen (fig. 636) regards the nuclei as merely associated in preparation for their ultimate union in the ascus. Dangeard, on the other hand, denies the dis- appearance of the wall between the oogonium and trichogyne or the passage of the male nuclei beyond the latter organ, and Brown has described a variety in which the trichogyne and antheridium fail to unite. 106 DISCOMYVGETES [CH. In any case the greater part of the male cytoplasm does not enter the oogonium but is left behind in the antheridium and trichogyne; con- sequently these organs, after their function is complete, remain, to the superficial view, unchanged for a long period, till they are crushed at last by the growth of the investing hyphae, or perhaps destroyed by bacteria (Harper, p. 354). Before the stages described above, the oogonium has begun to bud out (fig. 62a) at various points, giving rise to the ascogenous hyphae. Into these the nuclei pass, a few, no doubt unpaired, being left behind in the oogonium. The hyphae elongate, branch freely and undergo septation, and, as the vegetative filaments grow up, they ramify among them and at last bend over and give rise to asci from their penultimate cells. Claussen has described a paired arrangement of the nuclei in the ascogenous hyphae (fig. 63¢), and believes the members of each pair to be respectively male and female. After the ascogenous and vegetative hyphae are thoroughly interwoven, a rapid stretching upward of the whole mass ensues. In this growth the vegetative hyphae outstrip the reproductive ones, and form at first a cone- shaped mass, made up of their elongated, slender, densely aggregated tips. These upper extremities of the vegetative hyphae are the young paraphyses. Their number is constantly increased by the pushing in of new branches from below, and thus the conical outline of the mass is maintained. The ascogenous hyphae grow for a certain distance in company with the vegetative filaments, then their upward growth ceases, and they spread out horizontally, forming a rather dense layer below the cone of paraphyses. This is the base of the hymenium. Usually in Pyronema, as in Ascodesmizs, several oogonia are invested by a common sheath, and their ascogenous hyphae mingle to form the hymenium of a single ascocarp (fig. 64), but ascocarps developed in relation to a single pair of sexual organs are not unknown. The formation of the asci in Pyronema is quite typical. The number of chromo- somes is probably ten (Harper), or twelve (Claussen), at any rate in the first divisions in the ascus. Dangeard records a smaller a number in the third division, and in the Fig. 64. Pyronema confluens; diagram- matic section through ascocarp ; after variety enigneum Brown describes five Harper. throughout. Iv] PEZIZALES 107 As development proceeds the sexual organs become completely crushed and are at last no longer recognizable. At an early stage it becomes impossible to trace the connection between the ascogenous hyphae and the oogonium, and, during a great part of their development, these depend for their nutrition upon the paraphyses and other vegetative cells. A secondary mycelium grows downwards to the substratum, obtaining food material from it and serving for the attachment of the mature ascocarp. Special storage cells appear in the hypothecium. PYRONEMACEAE: BIBLIOGRAPHY 1863 DE BARY, A. Entwickelungsgeschichte der Ascomyceten. Leipzig. 1865 TULASNE, L. R. and C. Selecta fungorum Carpologia, ui. Imperial. typograph., Paris. 1866 TULASNE, L. R. and C. Note sur les phénoménes de copulation que présentent quelques Champignons. Ann. Sci. Nat. vi, p. 217. 1884 VAN TIEGHEM, Ph. Culture et développement du Pyronema confluens. Bull. Soc. Bet de France; xxxi, p. 355- 1885 KIHLMAN, O. Zur Entwickelungsgeschichte der Ascomyceten. Pyromema confluens. Acta Soc. Sci. Fennicae, xiv, p. 337. 1900 HARPER, R. A. Sexual Reproduction in Pyvonema confluens, and The Morphology of the Ascocarp. Ann. Bot. xiv, p. 321. 1905 CLAUSSEN, P. Zur Entwickelungsgeschichte der Ascomyceten. Aoudiera. Bot. Zeit. isi, p. 1. 1907 DANGEARD, P. A. Recherches sur le développement du périthéce chez les Ascomy- cétes. Le Botaniste, x, pp. 247 and 259. 1909 BROWN, W.H. Nuclear Phenomena in Pyronema confluens. Johns Hopkins Univ. @ice. vi; p. 42. 1912 CLAUSSEN, P. Zur Entwickelungsgeschichte der Ascomyceten. Pyronema confiuens. Zeitschr. f. Botanik, iv, p. I. 1915 BRown, W. H. The Development of Pyvonema confluens, var. tnigneum. Am. Journ. Bot. 1, p. 289. Pesizaceae The Pezizaceae form a rather large group. The ascocarp is superficial, sessile or stalked, usually with a well-marked peridium fleshy or waxy in consistency, and soon decaying after maturity. The spores are usually hyaline and continuous (though septate in some small species) and are typically uniseriate. The asci do not project above the level of the disc at maturity, as they do in the Ascobolaceae. The species are mostly sapro- phytic, many occurring on the ground, and a few, especially the smaller forms, on dung. The subdivisions depend on the shape of the spores, the size and consistency of the ascocarp, and the presence or absence of hairs. In the majority of forms the fruit is fleshy and without hairs; these species are often grouped together in the single genus Pezzza, but it is probably more convenient to separate them. The name /Pezza is retained for large species with a sessile or subsessile cup, regular in form and two 108 DISCOMYCE TES [CH. centimetres or more across as in P. veseculosa. The genus Humaria includes similar but smaller species, often less than one centimetre in diameter. In Otidea the sides of the ascophore are laterally split, or vertically incurved and wavy. In Acetabula and Geopyxis the ascophore is stalked. In Lachnea, as well as in some other genera, the fruit is beset with hairs and in Sepultaria it is hairy and more or less sunk in the soil. Lachnea stercorea is a small orange species occurring during the winter and spring on the dung of various animals, especially of cows. With Humaria granulata and Ascobolus furfuraceus, it is among the very common coprophilous forms, appearing in many parts of Britain with great regularity when the Pz/oboli have died down, and the cow pad is beginning to dry. It is about 4mm. in diameter and is furnished with numerous stout, septate hairs. The archicarp arises as a side branch from the vegetative mycelium, and divides to form four or more cells. The terminal cell or oogonium is oval in shape and larger than the others. It contains between two and three hundred nuclei and is filled with finely granular cytoplasm. In the cell next below the oogonium, the cytoplasm is also more dense and the nuclei more numerous than in the other cells of the fertile branch. Hyphae grow up from the lower cells of the archicarp, and from the branch which bears it, and form a dense weft above which the oogonium rises. Fig. 65. Lachnea stercorea (Pers.) Gill.; a. young archicarp, x 800; 4. archicarp and antheridium, x 500; P. Highley del. The oogonium sends out either laterally, or from its apex, a stout branch or trichogyne. It is cut off by a wall and divides into four to six cells, the terminal of which is much larger than the others (fig. 65a). The tip of the trichogyne protrudes for a time beyond the developing sheath, but later with the whole fertile branch, it is enclosed by vegetative hyphae. Iv] REZIZALES 109 At this stage a large, more or less oval sac is often found to be continuous with the terminal, or receptive, cell of the trichogyne into which a proportion of its contents pass (fig. 650). There seems no doubt that this sac is the antheridium, but its development is not known, and there is no evidence that its contents ever pass beyond the receptive cell of the trichogyne. Indeed all the available evidence shows that both antheridium and trichogyne are now merely vestigial structures. Nevertheless the development of the oogonium continues, its nuclei increase to something over 500 in number, and ascogenous hyphae bud out. Before passing into these the oogonial nuclei fuse in pairs, so that normal fertilization is here replaced by the union of female nuclei. The ascogenous hyphae branch and give rise to asci, in each of which eight spores are produced in the usual way. The karyokinetic figures are small but very clear, there are four chromosomes in the first and second divisions, but in the third telophase only two have been recorded. There is some evidence that the chromosomes show regular and characteristic differences of form, which reappear in successive divisions. The peridium, though much better developed than in the Pyronema- ceae, is never completely closed, as in Humaria or Ascobolus, across the top of the ascocarp. The paraphyses are numerous and contain orange granules. Lachnea scutelata occurs on decaying wood, forming bright red apothecia. The archicarp consists of seven to nine cells, the subterminal of which enlarges to form the oogonium. The nuclei in this cell divide, and, according to Brown, show five short, stout chromosomes. He did not observe nuclear fusion or association in the oogonium, but regards the nuclei lying in contact as the two daughter nuclei of a single mitosis. Large ascogenous hyphae develop, undergo septation, and branch freely. Their tips bend over and asci are formed in the usual way from the penultimate cells. The terminal cells may undergo further growth and give rise, as in several other Disco- mycetes, to new asci. Nuclear fusion takes place in the young ascus, and is followed by a meiotic reduction. Five gemini are recorded, but, in the anaphase of the first division, ten chromosomes travel towards each pole. This Brown takes to indicate an early fission of the daughter chromosomes. In the second and third divisions five chromosomes are seen throughout. Brown infers the occurrence of a single fusion in this species, that in the ascus, and a single reducing division! Lachnea cretea has a pale buff apothecium, beset with hairs (fig. 66a). It has been found on plaster ceilings, and, like many other saprophytic species, grows readily in artificial culture. 1 The magnification of Brown's figures of the divisions in the oogonium is enormous (x 11,200), and their details should therefore probably be received with some caution. 110 DISCOMYCETES [CH. The archicarp (figs. 66 d-e) consists of a long, branched, multicellular trichogyne, an oogonial region of three or four coenocytic cells, and a multicellular stalk. No antheridium has been observed. In the trichogyne (fig. 66), pores are formed between the adjacent cells, and are closed after a time by “callus” pads. In the central part of the archicarp the transverse septa are completely broken down, so that a very wide passage is formed, and nuclei pass readily from cell to cell (fig. 66/7). All the cells give rise Fig. 66. Lachnea cretea Phil.; a. mature ascocarp, x go; 2. c. development of archicarp, x 300; @. older archicarp showing crowded nuclei, x 4003; e. mature archicarp with elaborately branched trichogyne, x 400; /. three ascogonial cells united by very large pores, x 400. to ascogenous hyphae. Thus the oogonial region, though developmentally multicellular, is for all practical purposes unicellular at maturity, and offers no greater difficulties in the way of fertilization than the oogonium of Pyronema itself. The branched character of the trichogyne is exceptional among Disco- mycetes ; it might, no doubt, facilitate the establishment of contact with an Iv] PEZIZALES ra er attached antheridium if the latter developed at a distance. But branching might also be regarded as a secondary or vegetative development, appearing after normal fertilization had ceased to occur. The presence of pores in the transverse septa of the trichogyne suggests that the function of that organ in relation to an antheridium has only recently been lost. Fig. 67. Humaria granulata Quel.; young archicarp, x 320; after Blackman and Fraser. The ascogenous hyphae contain many nuclei irregularly arranged. Asci are formed in the usual way; their nuclei show about eight chromosomes in the first division. Owing to the small size of the nuclei further cytological details have not been studied in this species. 112 DISCOMY CE LES [CH. Humaria granulata is a common red or orange coprophilous form. The archicarp develops as a side branch from an ordinary hypha. The apical cell of this branch increases in size and becomes spherical, forming the oogonium (fig. 67); it contains large numbers of well-marked nuclei. When it is full grown the oogonial nuclei fuse in pairs (fig. 68 @), and the fusion nuclei pass into the ascogenous hyphae (fig. 68 4). There is no sign of either trichogyne or antheridium. Fig. 68. Humaria granulata Quel.; a. fusion of nuclei in oogonium, x 3200; 4. oogonium giving rise to ascogenous hyphae, x 1250; after Blackman and Fraser. Vegetative cells grow up and invest the archicarp, forming a close pseudoparenchymatous sheath in which the ascogenous hyphae ramify. They give rise at last to asci in the usual way. Four chromosomes have been recorded in the ascogenous hyphae, eight in the first division in the ascus and four in the two subsequent Iv] PEZIZALES 113 mitoses. This implies that the gametophytic number is four, and that the gemini are formed immediately after the fusion in the oogonium, so that in the ascogenous hyphae there are four bivalent instead of eight univalent chromosomes. In the meiotic prophase which follows the fusion in the ascus, there is a double number of gemini, since two sporophytic nuclei have united. In Humaria granulata, the antheridium has disappeared and normal fertilization is replaced by fusion of female nuclei in pairs in the oogonium. Fig. 69. MHumaria rutilans (Fr.) Sacc.; very young ascocarp, x 500. In another species of this genus, Hamarza rutilans', reduction has gone yet further and not even an archicarp is produced. The apothecium arises as a dense weft of tangled filaments, which for a time differ from one another only in the relatively thick walls of the outer hyphae, and the richer proto- plasmic content of the inner (fig. 69). Each cell of the weft contains one or a few nuclei. After a while the nuclei in the central part of the mass may be seen to be of two sizes, and the smaller have been found to fuse in 1 Humaria rutilans (Fr.) Sacc.= Pesiza rutilans Fr. in Boudier, /cones, Pl. 315. G.-Vi 114 DISCOMY CEES [CH. pairs (fig. 70a), giving rise to the larger. Sometimes in connection with this process a nucleus migrates through the wall from one cell to another (fig. 704), as in prothallia of ferns. Thus in 7. rutilans, where the sexual organs are completely lacking, normal fertilization is replaced by the union of vegetative nuclei in pairs. Fig. 70. Humaria rutilans (Fr.) Sacc.; a. fusion ina vegetative hypha; 4. migration of nucleus from one vegetative cell to another; both x rroo. The cells which contain fusion nuclei now give rise to ascogenous hyphae, while, from the rest, the paraphyses and cells of the outer sheath arise. The asci are very large, and their nuclei particularly clear. —The number of chromosomes in the nuclei of the ascogenous hyphae, and in the first and second divisions in the ascus and in the prophase of the third is sixteen (figs. 71,72). In the third telophase eight have been recorded by Maire and by Fraser (fig. 73), and sixteen by Guilliermond (fig. 74). Fig. 71. Humaria rutilans (Fr.) Sacc.; @. asco- genous hypha showing sixteen chromosomes in each nucleus, x 1950; 4. fusion nucleus of ascus passing out of synapsis, X 1300; ¢. fusion nucleus of ascus showing sixteen gemini, x 1950. IV] PEZIZALES 115 In several other members of the Pezizaceae, for example in Peziza vesiculosa (Fraser and Welsford) and Peztza tectoria, development appa- rently takes place, as in Humaria rutilans, without the formation of sexual organs. In Ot:dea aurantia (Fraser and Welsford), a large cell, no doubt part of an archicarp, has been recorded in the early stages, and in Peziza thele- boloides, Humaria Roumeguert, and FH. carbonigena, there is a well-marked oogonial region of one or more cells. ig. 72. Humaria riutilans (Fr.) Sacc.; a. telophase of second division in ascus, x 3370; &. prophase of third division in ascus, showing sixteen curved chromo- somes, X 2808. Fig. 73. Humaria rutilans (Fr.) Sacc.; a. meta- phase of third division in ascus, x 2080; 4. polar view of telophase of third division in ascus, showing eight curved chromosomes, x 3100. Fig. 74. Humaria rutelans; telo- phase of third division in ascus; after Guilliermond. 8—z2 116 DISCOMYCETES [CH. PEZIZACEAE: BIBLIOGRAPHY 1905 GUILLIERMOND, A. Remarques sur le Karyokinése des Ascomycétes. Ann. Myc. il, Pp. 343: 1905 MAIRE, R. Recherches cytologiques sur quelques Ascomycetes. Ann. Myce. iii, pe 123. 1906 BLACKMAN, V. H. and FRASER, H. C. I. On the Sexuality and Development of the Ascocarp in Humaria granulata. Proc. Roy. Soc. B.'77, p. 354. 1907 FRASER, H. C. I. On the Sexuality and Development of the Ascocarp in Lachnea stercorea. Ann. Bot. xxi, p. 349. 1908 FRASER, H. C. I. Contributions to the Cytology of Humaria rutilans. Ann. Bot. XXll, Pp. 35 1908 FRASER, H. C. I. and WELSFORD, E. J. Further Contributions to the Cytology of the Ascomycetes. Ann. Bot. xxii, p. 465. 1909 FRASER, H. C. I. and Brooks, W. E. St J. Further Studies on the Cytology of the Ascus. Ann. Bot. xxiii, p. 537- 1911 BRowN, W. H. The Development of the Ascocarp in Lachnea scutellata. Bot. Gaz. lii, p. 275: 1911 GUILLIERMOND, A. Les Progrés de la cytologie des Champignons. Prog. Rei Bot. vi, p. 389. 1913 FRASER (GWYNNE-VAUGHAN), H. C. I. The Development of the Ascocarp in Lachnea cretea. Ann. Bot. xxvii, p. 554. A scobolaceae The large majority of the Ascobolaceae are coprophilous ; their ascocarp is soft and fleshy or somewhat gelatinous, and they possess a well-marked sheath which is closed during the early stages of development. They are distinguished from the Pezizaceae by the usually multiseriate arrangement of their spores, and by the fact that, when ripe, the asci stand well up above the hymenium before the spores are discharged. Often the asci are large and few in number ; the spores are brown or violet in Ascobolus, Saccobolus and Loudvera, hyaline in the other genera; they are usually ellipsoid, but round in Loudera and Cubonia; in Saccobolus they are enclosed in a special membrane within the ascus and are ejected together; and in Thelebolus and Rhyparobus they are sixteen or more in number. In most of the species investigated there is a conspicuous multicellular coiled archicarp, the central part of which gives rise to ascogenous hyphae. Some of the species also produce conidia (A scobolus carbonartius), or chlamy- dospores (Ascobolus furfuraceus (Welsford), Asco- phanus carneus). Ascobolus furfuraceus is one of the commonest , dung species, the ascocarp is green or brown in Fig. 75. re NS SS wo Fig. 90. a. Helvella crispa (Scop.) Fr.; 6. and ¢. Morchella vulgaris Pers.; after Boudier. nuclear divisions, and finds two chromosomes in the vegetative and four in the fertile hyphae. Four again appear in the first and second (meiotic) divisions in the ascus, after the second fusion has taken place, and two are recorded in the telophase of the third division, and in the mitosis in the spore. The ripe spore normally contains eight nuclei. In both species, after an ascus has arisen from the penultimate cell of a hypha, the terminal cell may grow on, giving rise to others, and may fuse before doing so with the third cell of the hypha, which is the stalk-cell of the previously formed ascus. In Morchella esculenta the nuclear divisions of the ascus have been studied by Maire. After observing eight chromatin bodies in the prophase of the first division in the ascus, he found four in the prophase and anaphase of the third, and in the divisions of the spore nuclei; this corresponds closely with Carruthers’ results in Helvella crispa. HELVELLACEAE: BIBLIOGRAPHY 1905 MAIRE, R. Recherches cytologiques sur quelques Ascomycétes. Ann. Myc. iii, p. 123. 1910 MCCUBBIN, W. A. Development of the Helvellinaceae. I. He/vella elastica. Bot. Gaz. xlix, p. 195. 1911 CARRUTHERS, D. Contributions to the Cytology of He/vella crispa. Ann. Bot. xxv, p- 243. Iv | PEEVE EECALES 13h Geoglossaceae The Geoglossaceae grow usually in damp or moist situations such as low, wet woods and shady slopes. They occur on soil or on dead branches or leaves, and two species of MJvtrula are parasitic on living moss. The family includes some eight genera of which five are British. j ‘ / , ‘ ; ; ¢ } ' oe = ~ Fig. 91. a. Geoglossum hirsutum Pers., nat. size; 6. Spathularta clavata Sacc., nat. size; c. Leotia lubrica Pers., form stépztata, x 2; after Massee. The ascophore is erect and stipitate with the fertile portion terminal, and either club-shaped (fig. 91 a, 6), laterally compressed, or forming a cup or a pileus (fig. 91c¢.). In some of the simpler forms, as in Geoglossum hirsutum, there is no clear line of demarcation between the fertile and sterile regions. The ascus con- tains eight spores and opens by the ejection of a plug. The young ascocarp consists of a ff dense tangle of vegetative filaments; i HY in the early stages a more or less’ § at conspicuous veil has been identified 3 tH in several genera (though not as yet Yee in Geoglossum). It is composed, as i Ht in the Helvellaceae, of interwoven hyphae, derived fromand continuous with the outer layer of the fruit body. There are indications that it opens at first by a pore at the apex, but it soon breaks up into scales and dis- aes oo a Fig. 92. a. Geoglossum hirsutum Pers., x 220; 6. c S; 9 . > ~ ~ appears. Spathularia clavata Sacc., x 400; after Massee. 4 oO 2 132 DISCOMYCETES fees < In Leotia lubrica a large branching cell, presumably an oogonium, occurs at the base of the very young ascocarp and appears to give rise to the ascogenous hyphae. As far as the characters of the mature fruit are concerned, two lines of development can be traced, both starting from Geoglossum and passing, the one through Spathularia to Vebrissea, the other through J7z¢trula and Leotia to the Helvellaceae. In the species of Spathularia and Vibrissea, as in Geoglossum, the spores are very long, narrow and septate, lying side by side in the ascus. Geo- glossum is distinguished by its coloured spores (fig. 92@), the other two genera, in both of which the spores are hyaline (fig. 92), by the form of the fructification. In the rest of the Geoglossaceae, as in the Helvellaceae, the spores are elliptical and hyaline, and are arranged one above the other in the ascus. They may be continuous or septate. In J/ztrula the fertile region is irregularly club-shaped, and in Leodza pileate. A relationship to the Pezizales suggests itself at various points, and perhaps especially through Leofza, to the Helotiaceae and Mollisiaceae where, as in the Geoglossaceae, the ascus opens by a slit or pore from which a plug of wall substance is ejected, not as in the majority of the Helvellales and Pezizales by a definite lid. GEOGLOSSACEAE: BIBLIOGRAPHY 1897 MASSEE, C. A Monograph of the Geoglossaceae. Ann. Bot. xi, p. 225. 1908 DURAND, E. J. The Geoglossaceae of North America. Ann. Myc. vi, p. 387. 1910 BROWN, W. H. The Development of the Ascocarp of Leodéa. Bot. Gaz. 1, p. 443. PHACIDIALES In the Phacidiales the ascocarp is immersed in the matrix. It is usually small in size and leathery, waxy, or coriaceous in consistency; an epithecium is often developed. Certain members of the group resemble the Hysteriales in many points and differ from them chiefly in the greater exposure of the fertile disc at maturity. There are two chief families, Stictaceae The Stictaceae constitute a considerable group of small forms, occurring saprophytically on wood or other plant remains. Their development and minute anatomy, apart from systematic characters, is practically uninvesti- gated. They have a fleshy or waxy disc, pale and clear coloured, usually white, yellow, or tinged with pink. The sheath is not always developed, when present it is thin and white and is mealy owing to the presence of particles IV] PHACIDIALES 133 of calcium oxalate; when the fruit opens it forms a white border around the hymenium. The pale colour, and the ragged or toothed dehiscence of the sheath are very characteristic. Phacidiaceae The Phacidiaceae are distinguished by their black, thick-walled apothecia, usually scattered, sometimes, as in RAyt7sma, grouped on a black stroma. Where the fertile disc is circular the sheath splits in a stellate manner, but where it is elongated, dehiscence takes place by means of a slit running along its entire length. The species occur chiefly on dead herbaceous stems or leaves, but a few are parasitic. Rhytisma Acerinum (fig. 93) infects the leaves of various species of Acer (maple and sycamore). The mycelium ramifies in the living tissues of the VS a, , ie a Wy ti — Bho gual oes™ BI LP KS 2 53 sere ae 4, J Sestcesae Pegece ce ehedisca ere i 1 | 7 Kee AN vari = i goles STUUR TR Ay I esabt b Kh A LIAS) ‘| cM Yeas Y) [x G CNT 3 z AT} aos) FA AE oi EUG p : eb leg A E159 spare. QO CT oa Fig. 93. Ahytisma Acerinum (Pers.) Fr.; apothecium, x 160. host and causes yellow spots on the leaves about three weeks after infection. Some five weeks later pycnidia develop under the cuticle and produce small unicellular conidia. The epidermis and underlying tissues of the host become filled with hyphae and a dense, black sclerotium is completed. In this state the leaf falls and next spring the sclerotia thicken and become wrinkled; finally they burst by elongated fissures and expose the discs of the apothecia. The ascospores are filiform and septate; they are ejected with some force and reach the living leaves to which they are probably carried by the wind. HYSTERIALES The Hysteriales are characterized by the black, elongated ascocarp, dehiscing by a longitudinal slit, so narrow that the disc is almost permanently concealed. The species are all minute; in some the disc is narrowly elliptical, in 134 DISCOMY CETES [CH some it branches in a stellate manner, in others the ascocarp is raised and laterally compressed so as to resemble a miniature mussel or oyster shell standing on its hinge and with the opening uppermost. In this case, or when the ascocarp is superficial, it is rigid and carbonaceous in consistency, when developed beneath the epidermis of the host it is membranous. The ascospores are coloured or hyaline and are frequently septate; they may be very long and narrow and may be surrounded by a gelatinous membrane. In a few cases pycnidia are known, producing oblong, unicellular, hyaline conidia. The majority of species are saprophytic on old wood, bark, or dry leaves. The mycelium is intercellular, and is sometimes parasitic on living plants though the apothecia reach maturity only on parts that have been killed. The details of cytology and development are not known, nor do these minute species, growing often on a hard substratum, seem very promising objects of study. . The subdivisions of the Hysteriales, of which Hysteriaceae and Hypo- dermataceae are the chief, depend upon the consistency of the sheath, on the form of the ascocarp, and on whether it is superficial or immersed. Lophodermtum Pinastri (Hypodermataceae) produces pine-blight or needle-cast in the seedling of Pzzus sylvestris and other conifers, causing them to drop their leaves. The mycelium ramifies in the leaf and gives rise first to pycnidia and later, usually after the leaf has fallen, to ascocarps. These are black and oblong, opening by a narrow slit. The spores are filiform and continuous. The disease does very considerable damage to young plants, often causing death. It attacks mature trees also and, though these are not themselves seriously injured, they act as centres of infection, particularly in the neighbourhood of seedbeds and nurseries. In the form of their fructification the Hysteriales are intermediate between the Discomycetes on the one hand, and the Pyrenomycetes on the other, and have been variously included under either of these headings. Their black, coriaceous ascocarps, opening by a narrow slit, differ from those of certain Phacidiales chiefly in the less exposure of the disc. They approach the Sphaeriales in the frequent occurrence of coloured, septate spores, as well as in the consistency and often in the form of the ascocarp, which is distinguished from a true perithecium chiefly by its elongated opening, and by the absence of periphyses?. Possibly a study of their minute anatomy may lead to more definite knowledge of their relationships. ! For definition, see p. r4o. Iv] TUBERALES 135 TUBERALES The Tuberales are typically subterranean though some species are only imperfectly buried, or grow among decaying leaves. When mature the fruits emit a powerful odour by which rodents are apprised of their where- abouts. The ascocarp is eaten and the spores dispersed after passing through the alimentary canal of the animal. The ascocarp is more or less globose, sometimes completely closed, sometimes with a small opening. The hymenium may form a smooth lining to the fruit or may be thrown into elaborate folds so that the fertile region is divided into chambers. The asci contain one to eight spores, but, as far as is known, eight nuclei are always produced. The epispore is often elaborately ornamented at maturity. Early investigators classed the Tuberaceae with the hypogeal Gastero- mycetes, and a consequence of this survives in the use of the term gleba to describe the contents of the ascocarp, including both vegetative hyphae and hymenium. The Tuberales include a single family, the Tuberaceae; their relationship is probably to the Pezizaceae and Rhizinaceae. One or more series can be traced between these families and the truffles, the principal modifications being in the direction of adaptation to subterranean conditions by increased protection of the hymenium. This appears to have been achieved either by retaining the closed form of the young pezizaceous apothecium (Genea, Pachyphloeus) or by invagination of the fertile layer (Zzder) over a widely exposed surface such as is found in Afzzina or Sphaerosoma. In either case room has been made for additional asci by throwing the hymenium into elaborate folds. Massee, however, regards the globose asci and dark-coloured sculptured spores of 7wder as primitive, and derives from it Genea, and thence the Pezi- zales. y vin, wilt ; Meat ~ ‘hs jut’ eee aera > ~~. fD =e Tuberaceae In Aydnocystis and Genea the ascocarp is fleshy or warted; it has a single aperture often more or less closed by project- ing hyphae. Internally the é hymenium may formasmooth Fig. 94. @. Genea Kloteschit B. and Br.; ascus and para- tei ; : physis; 4. Genea hispidula Vitt.; apothecium; c. Ining, Or, in Genea, 1S more Genea sphaerica Vitt.; apothecium; after Massee. 136 DISCOMYCETES [CH. =) often divided into chambers, all of which communicate with the apical opening. The asci are cylindrical and contain eight uniseriate spores (fig. 94a). The simplest species in fact resemble a nearly closed Peziza (fig. 94 G, c). In Stephensta and Pachyphloeus the hymenium is more elaborately con- voluted ; the asci in Pachyphloeus are stouter, and the spores irregularly biseriate. In Balsamia (figs. 95, 96) the asci are broadly oblong or subglobose; the mature ascocarp is completely closed and surrounded by a pseudoparen- chymatous sheath. The youngest ascocarps of 4. Platyspora which Fig. 96. Balsamia vulgaris Vitt.; section Fig. 97. Zuber rufum Pico; general view through hymenium ; after Tulasne. of fertile region; after Tulasne. Vv] TUBERALES 137 Bucholtz was able to examine, showed a system of internal chambers lined by the hymenium and communi- cating at one or more points with the exterior. As development pro- ceeds these cavities increase in size and the hymenium becomes further convoluted, so that additional cham- bers are formed. In Zuber the ascocarp is ir- regularly globose, fleshy or some- times almost woody; internally the walls which divide the gleba are extensively branched, and the free space between them is diminished, so that the layers of the hymenium are brought close together and constitute the fertile “veins.” Other “veins, white and sterile, run be- tween the hymenial layers and serve as air chambers (fig. 97). The asci are often globose, and the spores usually four in number, but the number varies, and is sometimes reduced to two or one (fig. 98). Fig. 98. Tuber rufum Pico; section through The development of the fruit hymenium; after Tulasne. has been studied by Bucholtz in Tuber puberulum (fig. 99). The very young ascocarp consists of a mass of hyphae, the outer rather more loosely interwoven than the inner. Around the lower part a dense basal sheath is differentiated. Soon the first signs of the fertile veins appear as invagina- tions of the upper surface, and internally the loose tissue of the sterile veins. becomes recognizable. Owing to the rapid growth of the upper portion of the young fruit, the basal sheath is bent backwards, while at various points along the fertile veins the first signs of asci appear. Later the peripheral tissues become thickened, together with the remains of the basal sheath, and form the peridium. This ultimately closes over the points where the fertile veins are in communication with the exterior. Thus the young fruit is open at first, the hymenium becomes internal by invagination and the peridium which covers the mature ascocarp is a secondary formation. The development of the fructification in Chotromyces macandriformtis approaches that of 7. pudberulum, but the basal sheath and peridium are less conspicuous. 138 DISCOMYCETES [CH. IV The ascocarps of many species of 7uder are edible, the most esteemed being 7. melanosporum which does not occur in Britain. They grow chiefly Fig. 99. Zuber puberulum (B. and Br.) Ed. Fisch.; a.—e. development of ascocarp; a. x 52; 6.andc. x 28; d. and e. x 21; /. section through mature ascocarp, x 6; all after Bucholtz. in soils consisting of sand mixed with clay and containing iron, or in mixed alluvium; the soil must be porous to secure sufficient aeration. Truffles occur in chestnut, oak, and especially beech woods and there is evidence that they form mycorhiza with the roots of these trees. The relation would appear to be of advantage to the fungus since the success of the culti- vation of edible truffles under oaks in France depends on keeping the roots near the surface. TUBERACEAE :. BIBLIOGRAPHY 1903 BUCHOLTZ, F. Zur Morphologie und Systematik der Fungi hypogaei. Ann. Myc. 1, Pot52: 1905 FAULL, J. H. Development of Ascus and Spore Formation in Ascomycetes. Proc. Boston Soc. Nat. Hist. xxxil, p. 77. 1906 BOULANGER, E. Notes sur la Truffe. Soc. Myc. xx-xxii, pp. 77 etc. 1908 BUCHOLTZ, F. Zur Entwickelung der Choiromyces Fruchtk6érper. Ann. Mye. vi, Pp. 539: 1909 MASSEE, G. The Structure and Affinities of British Tuberaceae. Ann. Bot. xxiii, p- 243. 1910 BUCHOLTZ, F. Zur Entwickelungsgeschichte des Balsamiaceen-Fruchtk6rpers nebst Bemerkungen zur Verwandtschaft der Tuberineen. Ann. Mye. viii, p. 121. CHAPTER V PYRENOMYCETES THE Pyrenomycetes include some 10,000 species ; they are characterized by the fact that their ascocarp or perithecium is a more or less flask-shaped organ opening by a narrow pore, the ostiole, and containing a hymenium spread in a regular manner WB over the floor and lower part of the sides (fig. 100). It thus differs from the perithecium of the higher Plectascales where the asci are irregularly scat- tered, and from that of the Erysiphales where, except in the flattened perithecium of the Microthyriaceae, an ostiole is not developed. By some au- thors the term Pyrenomycetes is used to include all these groups and even certain other forms, such as the Tuberales. A study of the development of the truffles, however, has made a Es , .y: ap Se a BSA Se Sa eK Z =~) en bla e Q = = Oxo aS PSS SECSH PS, S Ss Q >®. 0, < SS 0, clear their affinity with the = << : ; B iL SS : oF = =, Ss Pezizales; the mildews consti- see Beet | tute a well defined and isolated =a group, distinguished, so far as ; FRE they are known, by the form NCS of their sexual organs ; and Z the higher Plectascales differ Fig. 100. Sordarza sp.; ascocarp in longitudinal section from the present series and re- showing asci, paraphyses and periphyses, x 400. semble the simpler forms with which they have here been classified in the important character of the arrangement of their asci. There remain four groups, the Hypocreales, the Dothideales, the Sphaeriales, and the Laboulbeniales. The last are true Pyrenomycetes in the sense that they possess regularly arranged asci'and a perithecium opening by an ostiole, but they are dis- tinguished by so many special characters that, though included under this heading, they can best be dealt with apart. 140 PYRENOMYCETES [CH. The Hypocreales, Dothideales and Sphaeriales, have in common more or less pyriform or flask-shaped perithecia; these are sometimes isolated and free, sometimes sunk in the tissue of the host, and sometimes embedded in a stroma or cushion of fungal tissue. The perithecium is lined by delicate filaments, some of which, the periphyses, grow along and partially close the neck, and may protrude through the ostiole, while others (paraphyses) are mingled with the asci in the venter of the fruit. The neck of the peri- thecium varies very much in length, and is often markedly phototropic, the ostiole being directed towards the light, and thus incidentally towards a clear space so that, when the spores are shed, as wide a distribution as possible is ensured, So definite is this reaction in, for example, species of Sordarza, that if the direction of light be changed every four or five days during development, a series of corresponding bends in the neck are produced. In Sordaria and its allies the asci elongate, reaching up to the ostiole and in turn discharging their spores; in species of Spumatoria and Chaetomtum the asci deliquesce to form a mucilaginous mass which readily absorbs water and expands, being squeezed up the neck and exuded at the ostiole where it persists until dissolved by rain or dew. Accessory fructifications include chlamydospores and various types of conidia which may be borne separately on free conidiophores, or grouped together in pycnidia. In some cases there is evidence that the so-called pycnidia are spermogonia, and the spores they produce spermatia, but no case has been brought to light in which these still fulfil their function as fertilizing agents. A consideration of our rather scanty knowledge of the initiation of the perithecium in this group brings to light three main types of development. (i) In Chaetomium, in Sordaria (fig. 101) and its allies and in species of Hypomyces and Melanospora there is a coiled archicarp of four or five cells; these are uninucleate in Hypomyces lateritus, Chaetomium spirale and Podospora hirsuta, multinucleate in Sordaria and Hypocopra and in other species of Chaetomium. In Sordaria macrospora the archicarp is straight instead of coiled and in S. fimiseda a swollen terminal cell has been reported. A pair of initial hyphae has been described in Rosellina quercina, but in no case has a sufficiently detailed study been made either to reveal nuclear fusions in the archicarp or to justify the inference that they do not occur. ; Under these circumstances it is possible to judge of the function of these initial filaments Fig. 101. Sordaria fimicola Rob. archicarps; after Dangeard. v] PVE NOMY CETES 141 only on the somewhat incomplete evidence that they give rise to ascogenous hyphae and on the basis of their resemblance to the sexual branches of other Ascomycetes. There is a very similar coiled hypha in certain species of Eurotium which is certainly a functional archicarp. Comparison may also be made with the female branch of Ascodesmis nigricans and with that of the Erysiphaceae. (ii) The second type of pyrenomycetous initial organ (fig. 102) may Fig. 102. Polystigma rubrum DC.; mature archicarp, x 800; after Blackman and Fig. 103. Xylaria polymorpha (Pers.) Grev.; Welsford. archicarp embedded in stroma, x 1000. readily be derived from the first. It occurs in forms where the perithecium is immersed either in the substratum or in a stroma, and its essential character is the prolongation of the tip of the archicarp to form a trichogyne-like organ. The appearance of this structure is associated with the development of spermatia in spermogonia. Archicarps of the type in question are found in Polystigma among the Hypocreales and in Gnomonta, Poronta and Mycosphaerella among the Sphaeriales. In all these genera, however, the trichogyne appears to be merely vestigial; in Polyst7gma it never reaches the exterior of the host-leaf, in Gromonza its connection with the coiled oogonial region is doubtful and in J/ycosphaerella and Poronia it degenerates early. In Polystigma the ascogenous hyphae arise from vegetative cells and not from the archicarp and it is at least possible that the same is the case in the other genera named. A comparison is obvious between the archicarps of these forms and those of several Lichens and of such Discomycetes as 142 PYRENOMYCETES [cH. Lachnea cretea and the Ascobol’, where the coiled and septate archicarp is often still functional. A very common initial organ in forms with embedded perithecia is the short filament of cells sometimes known as Woronin’s hypha (fig. 103). The cells are large and contain well-marked nuclei and lie in a nest of small- celled vegetative mycelium. Woronin’s hypha has been found among the Hypocreales in Vectrza and among the Sphaeriales in Xy/arza and Hypoxylon ; it remains to be shown whether SS it still functions. It may have originated from the simple archi- carps of the Lower Pyrenomy- cetes or by reduction from forms with a multicellular trichogyne. With its final disappearance we reach such completely apogamous species as those of Cordyceps and Claviceps. fi i (iii) A quite distinct type of primordium has been described in Stveckeria, Sporormia and Pleo- \ spora; in these cases the asco- genous and vegetative filaments arise from a common initial cell Fig. 104. Stréckeria sp.; initial cells of ascocarps}; which divides not only transverse- after Nichols. ly, but longitudinally, forming a compact tissue (fig. 104). Other hyphae may anastomose with this mass, or it may give rise alone to the whole fructification. Possibly some sugges- tion of its origin may be found in the peculiar, but apparently normally fertilized oogonium of Leptosphaeria. The Pyrenomycetes do not appear to have given rise to any higher forms, and have themselves a greater vegetative development than any other Ascomycetes. They may be subdivided as follows : Wall of perithecium differentiated from stroma; perithecium wall and stroma, if present, soft in texture, either colourless or light coloured HYPOCREALES. perithecium wall and stroma, if present, firm, leathery or brittle, dark in colour SPHAERIALES. Perithecium always sunk in a stroma from the tissue of which its wall is not differentiated ; colour of stroma black or dark brown DOTHIDEALES, Minute, external parasites on insects, perithecium borne ona receptacle which also bears appendages; spores two-celled LABOULBENIALES v] HY POCREALES 143 HYPOCREALES The Hypocreales are readily distinguished by the clear colour and more or less fleshy consistency of the perithecium or stroma. In the majority of Pyrenomycetes the colour is black or dark brown, but here bright red, yellow, blue, and various paler shades are found, and it is only quite occasionally that so dark a tint as brown or dirty violet appears. The asci contain usually eight, sometimes four, and sometimes many spores. The spores are in most cases hyaline, but are dark-coloured in Melanospora and its allies; they are elliptical or filiform, and may be one or more celled: In a number of species conidia as well as ascospores are produced. The group includes both saprophytic and parasitic forms. There are some sixty genera of Hypocreales, and the group is subdivided primarily according to the development of the stroma. In the simplest forms the stroma is absent, and the separate perithecia may or may not be partly sunk in the substratum, in others a filamentous or a fleshy stroma appears, and the perithecia are more or less embedded. In the highest members the perithecia originate deep in the stroma, and remain immersed in it throughout their development. Upon these characters the subdivision of the group is based : Stroma absent, or, when present, with perithecia entirely superficial NECTRIACEAE. Stroma forming a conspicuous matrix in which the peri- thecia are partially or entirely immersed HyYPOCREACEAE. Nectriaceae The species of the genus Hypfomyces are for the most part parasitic upon the pilei of various Hymenomycetes. 7. aurantius occurs on old Polypore and on species of Stereum. Here the free perithecia are roughly oval in form, orange yellow in colour, and seated on a delicate filamentous stroma. The perithecium wall consists of an outer coat of narrow, closely woven hyphae, and an inner layer of larger, thinner-walled cells with scanty contents. The cavity becomes filled with paraphyses and developing asci, and is prolonged into the neck lined with short periphyses. The spores are two-celled and the wall at each end is usually prolonged into a point. Development has been studied by Moreau in Hypomyces lateritus, a form parasitic on species of Lactertus, and placed by Maire in the genus Peckzella by reason of its unicellular spores. The cells of the vegetative mycelium are uninucleate, and the archicarp appears among them as a coil of uninucleate 144 PYRENOMYCETES [CH. cells; there is no sign of an antheridium. Nuclear division without wall- formation takes place in the archicarp so that each cell contains two or occasionally three nuclei. At a later stage, after abundant branching, the young perithecium contains a number of binucleate cells; from these the asci arise, the hypha bending over and cutting off a binucleate subterminal cell in the usual way. No fusion but that in the ascus was observed by Moreau. The chief interest of this life history lies in the origin of the bi- nucleate condition, as insome Basidiomycetes, by nuclear division. In JZelanospora the stroma may be absent, but when present is charac- teristically fleshy; the perithecium neck is elongated; the species occur on the fructifications of the Pyrenomycetes, on those of Pezizaceae and Tuberaceae, on various plant remains and in one or two cases on living plants; thus JZ. damnosa may be a serious disease on wheat and rye. The development of JZ. parasitica was studied by Kihlman; this species is a parasite on certain fungi parasitic on insects, including Cordyceps militaris, which is itself a member of the Hypocreaceae. The first sign of the development of perithecia is the yellow coloration of the mycelium, which has hitherto been white. The archicarp is a stout, twisted, multicellular hypha forming two or more coils and ending in a somewhat pointed cell; its growth is renewed after the development of the sheath has begun and it divides into some fifteen cells; one of these, which may be termed the ascogenous cell, divides in three directions, forming a true tissue from which the asci arise. Melanospora Zobelit is parasitic on various fungi and especially on the disc of certain Pezizaceae; Nichols found that the spores germinate to give rise to a mycelium in the cells of which the nuclei are arranged more or less in pairs’. The archicarp is a coiled or curved branch which becomes septate; near it a more slender antheridial hypha may develop, and, in some cases, may fuse with the female organ. Vegetative hyphae give rise to a sheath of the usual type with an outer layer, two or three cells thick, of thick-walled, isodiametric cells, and an inner layer of laterally compressed tubular cells; within this is a loose spongy parenchyma of cells rich in contents from which the asci arise. A connection between the archicarp and the asci has not been traced, but it seems probable that the whole central tissue of the perithecium may be derived from the divisions or branches of the archicarp perhaps, as in J/. parasitica, by means of an ascogenous cell. A further study of the development of the perithecium and especially of the origin of the asci in this genus is much needed. The facts, especially in M. parasitica, suggest that the divisions of the archicarp after the develop- ' Melanospora Zobeltt (Corda) Fuckel= Ceratostoma brevirestre Fuckel. * Presumably owing to rapid division ; cf. p. 47, ave. v] HYPOCREALES 145 ment of the sheath has begun, may correspond to the septation of the fertilized oogonium in other forms. Further, the origin of the asci from a single cell points to the Erysiphales and Laboulbeniales, and in view of the longitudinal divisions, perhaps especially to the latter. In WVectrza the usually red or yellow perithecia are produced in groups on stromata of the same colour; the asci contain eight ascospores which are two- celled, and often produce conidia by budding while still in the ascus. The genus is large, including some 250 species among which J. cexnabarina, the commonest in this country, is of very frequent occurrence on the living and dead branches of deciduous trees. The mycelium from the germinating spores is unable to penetrate the bark of the host, and infection takes place only through open wounds. Once established, however, the mycelium spreads rapidly especially in the xylem. The cambium and other tissues are not attacked but die as a result of the destruction of the wood, so that as develop- ment proceeds branch after branch is killed. Meanwhile the stromata appear (fig. 105); in the conidial stage they are bright pink and occur at all seasons Fig. 105. Vectria cinnabarina (Tde.) Fr. on a fallen twig; a@. conidial stroma; 6. young perithecia; x6; E. J. Welsford del. on the dead and living branches; perithecia are produced only in the autumn and winter and only after the tissues have been killed; they are deep red in colour and are partly immersed in the deep red stromata. When a peri- thecium is about to be formed a coil of hyphae larger than the ordinary filaments of the stroma appears a little below the surface, and probably represents the remains of whatever sexual apparatus originally gave rise to the ascogenous hyphae. Nectria cinnabarina is thus one of the rather numerous fungi which pro- duce conidia during their parasitic phase, and ascospores only when the death of the host has rendered them saprophytic. In view of the life-history of this species it is obvious that there are two methods of checking the damage which it does; the burning of infected branches on which the development of the spores takes place, and the painting over of open wounds through which alone the entrance of the mycelium is effected. G.-V. |e) 146 PYRENOMY CETES [CH. NECTRIACEAE: BIBLIOGRAPHY 1882 Mayr, H. Ueber den Parasitismus von Nectria cinnabarina. Untersuchungen aus der forstbot. Institut zu Miinchen, 11, p. 1. 1885 KIrHLMAN, O. Zur Entwickelungsgeschichte der Ascomyceten J/elanospora para- sitica. Acta Soc. Sci. Fennicae, xiv, p. 313. 1896 NicHoLs, M. A. The Morphology and Development of certain Pyrenomycetous Fungi. Bot. Gaz. xxii, p. 301. 1909 MASSEE, G. Ona New Genus of Ascomycetes (Gzésonza). Ann. Bot. xxili, p. 335. 1909 SEAVER, F. J. Notes on North American Hypocreales. Mycologia, i, p. 41. 1914 MOREAU, F. Sur le développement du périthéce chez une Hypocreale le Peckiella laterita, (Fries) Maire, R. Bull. Soc. Bot. de France, Ixi, p. 160. Fly pocreaceae Polystigma is a small genus, the best-known member of which, P. rubrum, develops on the leaves of Prunus spinosa, of P. mmsitztia and of the cultivated plum, where it produces conspicuous orange, yellow or scarlet stromata. Each of these is the result of a separate infection, and spreads over only a small part of the leaf, so that in autumn, when the leaves are shed, the host is freed from the disease. The fungus, however, hibernates in the fallen leaves, and next spring the ascospores mature, reach the young leaves and there germinate. Its development was first studied by Fisch in 1882, and by Frank in 1883, and these authors described trichogynes and the union of the latter with spermatia. More recent investigations, however, have shown that these organs, though present, are now no longer functional. The germinating ascospore gives rise to a mycelium which ramifies among the cells of the host and forces them apart; the hyphae become massed especially in the intercellular spaces below the stomata, and often push their way to the exterior between the guard cells. Finally the stroma may extend from the upper to the lower epidermis, and only a few isolated cells of the mesophyll remain in the infected region. The hyphae are multi- nucleate, they contain orange pigment and their originally thin walls are modified to form thick gelatinous membranes perforated by fine pits. The gelatinous walls are probably utilized as reserve material, for they are partly absorbed during the later stages of development after the fall of the leaf. During the summer, large flask-shaped spermogonia appear and open on the underside of the leaf, usually in the position of a stoma. The wall of the spermogonium consists of densely interwoven filaments and it is lined by thin, uninucleate spermatial hyphae (fig. 106). The mature spermatium is a filiform curved structure, narrowed at its free end; it contains a single, much elongated nucleus, staining homogeneously, and occupying the lower half or two-thirds of the cell. All attempts to bring about the germination v] HY POCREALES 147 of these spermatia have failed, and no relation of any kind has been de- monstrated between them and the female organ, consequently they must be regarded as no longer functional, and their original use can be inferred only from their structure. Their small size, scanty contents, and large nucleus suggest that they are more appropriately constituted to act as fertilizing agents than as a means of vegetative propagation. The archicarp first appears as a multinucleate hypha, which becomes septate and somewhat elaborately coiled. The base can usually be traced to a vegetative filament; the apex ends freely in the mass of uninucleate mycelial cells (fig. 102); most of the cells of the archicarp contain several nuclei, but a few are uninucleate. The archicarps usually develop singly, generally below or near a stoma, through which vegetative filaments project (fig. 107). These projecting hyphae were regarded by Fisch and Frank as ay SLD Ne Ss am “a Fig. 107. Polystigma rubrum DC.; vege- tative hyphae projecting through stoma above archicarp, x goo; after Blackman and Welsford. Fig. 106. Polystigma rubrum DC.;sper- mogonium, x 250; after Blackman and Welsford. trichogynes, but Blackman and Welsford, and later Nienburg, failed to trace any connection between them and the coiled archicarps. On the contrary, the latter end blindly within the stroma with or without branching, and it is only quite occasionally that they can even be traced upwards towards the stomata. Nienburg observed the formation of a pore between a multinucleate cell at the base of the archicarp and the large uninucleate cell next in order to it. Ata later stage he found that the uninucleate cell had become binucleate, the nuclei being at first somewhat different in structure, and that certain large cells, which apparently developed from it, also contained Ic—-2 148 PYRENOMYCETES [CH. two nuclei each. In his opinion, the second nucleus in the originally uni- nucleate cell, is derived from its multinucleate neighbour, which he terms the antheridium ; the other binucleate cells receive their nuclei from it by conjugate division, and are the beginnings of ascogenous hyphae. Though he was unable to see either the entrance of the second nucleus, or the process of conjugate division, his facts are decidedly suggestive, but they point less to normal fertilization than to the pseudapogamous association of a vegetative and a female nucleus. The binucleate character of the later formed large cells may, as he suggests, be due to conjugate division, but, since he finds that the numerous binucleate cells in the sheath! are the result of rapid growth, this character in the large cells is evidently susceptible of the same explanation. In any case the rest of the archicarp degenerates and owing to the refractory character of the material the ascogenous hyphae could not be further traced. According to Blackman and Welsford, all the cells of the archicarp degenerate without giving rise to ascogenous hyphae, and being functionless, retain their contents so that they can be recognized during the later stages of development as densely staining masses (fig. 108). The perithecia (fig. 109) arise in their neighbourhood, one in association with each archicarp, and the vegetative cells produce ascogenous hyphae, which become dis- tinguished by their large size, dense contents and well-marked nuclei. These Fig. 108. Polystigma rubrum DC.; young perithe- Fig. 109. Polystigma rubrum DC.; mature peri- cium; the ascogenous hyphae are not yet clearly thecium, x 270; after Blackman and Welsford. distinguished, many of the nuclei are in pairs, the darkly stained remains of the archicarp are visible near the periphery; x 680; after Blackman and Welsford. 1 Nienburg, p. 390, end of first paragraph. Vv] HYPOCREALES 149 @ authors found some evidence that a first nuclear fusion takes place in the ascogenous hypha before the differentiation of the asci. The ascus is formed in the usual way from the penultimate cell of the hypha; the usual nuclear fusion and successive nuclear divisions take place during its development. In the genus Podocrea, the stroma is erect, and sometimes branched; in Fiypocrea it is usually hemispherical or bolster-shaped and is colourless, or yellow or brown in colour. The majority of species occur saprophytically on wood, or as parasites on the larger fungi. In both genera and in their immediate allies, the spores are two or more celled. The systematic position of Podocrea alutacea’ has undergone curious vicissitudes; in con- sideration of its form it was at first placed among the Basidiomycetes as Clavaria simplex, \ater it was regarded as a compound structure, the pyreno- mycetous fungus being held to be parasitic, according to different authors, on Clavarza ligula and on species of Spathularia. The stalk being thus attributed to another fungus, the ovoid perithecial portion was referred to the genus Hypocrea. The question was set at rest by Atkinson, who succeeded in growing the normal upright stromata in pure culture from ascospores alone, and thus demonstrated that only one fungus was concerned. The species of Epzchloé occur parasitically on grasses the stems of which become coated by the stromata. The stroma is at first white, then yellow; in the early stages of its development oval conidia are produced, later the peri- thecia, which are completely embedded in the stroma, reach maturity; the ascospores, like those of the remaining genera of the Hypocreaceae, are fili- form; Dangeard has shown that they are at first elliptical and uninucleate; later they elongate, the nucleus divides and the spore undergoes septation. The genus Cordyceps (fig. 110) includes about sixty species; these are mainly tropical forms parasitic on insects, the bodies of which they transform into sclerotia from which the stromata grow out. The peculiar appearance of these structures has given rise to curious views as to their significance and medicinal value; thus Berkeley reports that Cordyceps sinensis is a “celebrated drug in the Chinese pharmacopoeia, but from its rarity only used by the Emperor’s physician.” The striking belief that it is “a herb in summer and a worm in winter,’ may perhaps sufficiently account for the esteem in which it was held. The ascospores are multicellular and filiform and when shed break up into their separate cells. Germ-tubes from these, or from the conidia, infect the insect either as a caterpillar or chrysalis, and penetrating into its interior give rise to cylindrical conidia which enter the blood-stream and increase by yeast-like budding till the insect dies. A mycelium then appears and 1 Podocrea alutacea Lindau= Podostroma alutaceum (Pers.) Atkinson. 150 PYRENOMYCETES [cH. the formation of the sclerotium begins; chains of subaerial conidia may be produced on conidiophores arranged in a coremium or fascicle of parallel hyphae. This is the Tsarta condition, and though there is little doubt that it is a stage in the development of the Cordyceps, the ultimate proof by culture has yet to be given. a b Fig. 110. a. Cordyceps militaris (L.) Link ; 6. Cordyceps ophioglossoides (Ehrh.) Link; after Tulasne. The mature sclerotium is a cormpact mass of interwoven hyphae whose cells are rich in glycogen and oily matter. During its development the in- ternal organs of the host are completely destroyed and replaced by the mycelium, the skin alone remaining intact. From this mummified structure one or more stromata arise, emerging between two segments of the skin, usually near the head. The stroma is differentiated into an erect, sterile stem, which may be simple or branched, and a globose or elongated, fleshy, fertile portion, usually terminal on the stem and bearing the perithecia (fig. 111). It is pale or bright coloured; red in the best known British species, C. militar’s ; and in other forms, purple, flesh-coloured, lemon-yellow or of various shades of brown. ¥] HYPOCREALES 151 As development proceeds the ovate or flask-shaped perithecia are dif- ferentiated ; they always arise deep in the stroma and may remain completely or partially immersed or may become superficial as they approach maturity. Where they are more or less free the surface of the head is usually rough, whereas when ; \ ' dt) NG they are entirely immersed it is smooth, i wali Nth but in some cases the free perithecia stand iin H Wi so close together as to produce a smooth ) My | i appearance. The cytological details of | i ) development have not been studied; the Yk ! \ pi perithecia arise from the vegetative cells Bay ( : Same : of the stroma and in no case have any signs TY SAVERS BANG () Vig ACY oN NSAI of sexual organs been seen; it would thus * MSc an appear that Cordyceps is completely apoga- Y \\ 0 SHKe NY WAR : ) > <— DS) (NAS mous. The first sign of the perithecium A YN er is the differentiation of a knot of deeply ee ess = \\ J staining vegetative hyphae. XS The asci are long and slender with NS slightly swollen apices into which the spores Fig. 111. Cordyceps Barnesti Thwaites; do not penetrate; at maturity the contents pease hac ita eee of the apex swell and the wall is ruptured. The spores are arranged in a parallel manner, ina fascicle slightly twisted onits axis, and are nearly as long as the ascus; they are hyaline, very slender and almost always multicellular; they break up readily into their constituent cells which, as already stated, germinate separately to infect a new host. According to the investigations of Lewton-Brain several nuclear divisions take place in the ascus before spore-formation and the spores are multinucleate from their first inception. Two species, C. ophzoglossozdes (fig. 1106) and C. capitata, are parasitic on underground fungi of the genus Elaphomyces and do not produce true sclerotia; for these reasons they are sometimes separated as another genus Cordylia. The species of Claviceps, like those of Cordyceps, possess filiform asco- spores, and form sclerotia from which the stromata arise. The genus is, however, much smaller, including only six species parasitic on various Gramineae. Of these the best known is the almost cosmopolitan species C. purpurea, the ergot, on rye and other cultivated grasses. The ascospores germinate on the flowers of the host, and give rise to a mycelium which ramifies at first in the outer coats of the ovary and ultimately filts its whole cavity, forming a sclerotium. Outside the ovary, conidia are budded off, and at the same time a sweet fluid, the so-called b) honey-dew, is excreted ; it attracts insects which carry the conidia with 152 PYRENOMYCETES [CH. them to other flowers, where they at once germinate, and further infections are produced. On the completion of the conidial stage the sclerotia assume a firmer texture, and become dark purple or bluish black in colour. If they fall to the ground or are sown with the seed they give rise next spring to numerous stromata with violet stalks and reddish yellow heads. According to Fisch, the perithecia originate from two or three hyphal cells, which become filled with strongly refractive protoplasm and divide in all directions to form a roundish mass of cells distinguished from those of the rest of the stroma by their size and contents. As in Cordyceps, there is no trace of sexual organs. The perithecia are immersed in the stroma, and the asci produce filiform but continuous spores. The sclerotium is well supplied with reserve materials and contains certain poisonous substances including ergotic acid, a narcotic which diminishes reflex excitability ; sphacelic acid, the main cause of ergot poisoning, it gives rise to gangrene, and large doses produce tetanus of the uterus and cramp; cornutin, an alkaloid causing contraction of the uterus. Thus the ergot sclerotia, ifeaten with the grass by cattle, or included in the grain used for bread-making, are responsible for serious disease. When grain was less carefully purified than at present the inhabitants of whole districts sometimes became afflicted with gangrene, and the occurrence of the sclerotia in pastures is liable, owing to the presence of cornutin, to cause abortion in sheep or cows, so that many local traditions as to the prevalence of abortion in certain farms, or in certain byres, are probably traceable to this cause. Cornutin is of medicinal value, and the sclerotia are collected for this purpose. HYPOCREACEAE: BIBLIOGRAPHY 1843 BERKELEY, M. J. On some Entomogenous Sphaeriae. London Journal of Botany, It: 205. 1882 FiscH, C. Beitrage zur Entwickelungsgeschichte einiger Ascomyceten. Bot. Zeit. xl, p. 850. 1883 FRANK, E. Ueber einige neue oder wenige bekannte Pflanzen Krankheiten. Ber. der deutsch. bot. Ges. i, p. 761. 1895 Masser, G. A Revision of the Genus Cordyceps. Ann. Bot. ii, p. 207. 1901 LEWTON-BRAIN, L. Cordyceps ophioglossoides, Ann. Bot. xv, p. 522. 1905 ATKINSON, G. F. Life-history of Wypocrea alutacea. Bot. Gazette, xl, p. 401. 1907 DANGEARD, P. A. Recherches sur le développement du périthéce chez les Ascomy- cétes. Le Botaniste, x, p. 352. 1912 BLACKMAN, V. H. and WELSFORD, E. J. The Development of the Perithecium of Polystigma rubrum. Ann. Bot. xxvi, p. 761. 1914 NIENBERG, W. Zur Entwickelungsgeschichte von Polystigma rubra. Zeitschr. fiir Bot. vi, p. 369. DOTHIDEALES The Dothideales constitute a small group of some four hundred species, included in twenty-four genera, forming a single family, the Dothideaceae. They are parasites or saprophytes on the leaves and stems of higher plants, v] SPHAERIALES 153 on which they produce stromata usually below the epidermis and finally exposed by its rupture. The stroma is externally black and hard, built up of hyphae closely interwoven to form a pseudoparenchyma; internally it is of much looser consistency, and is often white or brownish in colour. The perithecia are without definite walls, so that the asci develop in mere cavities in the stroma, which however have the globose form of ordinary perithecia, and are bordered by cells rather smaller and narrower than those of the surrounding mycelium. In some cases, where the inner tissue of the stroma is very loosely interwoven, the perithecium is, however, definitely delimited. _In Dothidea the stromata form black projecting cushions, which in D. virgultorum occur on the living, as well as the dead stems and branches of the birch. In Plowrightia the very similar stromata run together in masses. P. morbosa is a serious disease attacking species of Prunus, especially the cherry and plum. The mycelium penetrates the living branches which become swollen and deformed and on which stromata and finally perithecia are produced. SPHAERIALES The Sphaeriales are distinguished by the dark colour and membranous, corky or carbonaceous texture of their perithecia, and of their stromata when present. They number already considerably over six thousand species, and new species are constantly being brought to light, so that there is no doubt that a study of the tropical forms, at present very incompletely known, will greatly increase their number. Not only the number of species, but the number also of individuals is very considerable; the majority are saprophytes, and serve a useful purpose in bringing about the first stages of decay in such resistant materials as wood and straw. They greatly outnumber the Hypocreales and Dothideales, and it is from their black or brown colour and often charred appearance that the name Pyrenomycetes is derived. The origin of the group has been proposed through Chaetomium, which is sometimes without an ostiole, from the Erysiphales, or, in view of the structure of the sexual organs, from an Lwrotium-like form among the Plectascales. Unfortunately their small size and resistant texture as well as the nature of their habitat make many of the simpler species unfavourable subjects of study, and our knowledge of their development is at present very fragmentary. Sordaria and some others can be grown on artificial media and satisfactory results may be anticipated from a further application of this method. Some of the larger forms with a well-developed stroma can readily be handled but in none of these has normal sexuality yet been observed. The perithecia in the simplest forms are borne singly, free or partially 154 PYRENOMYCETES [CH. embedded in the substratum; from these may be traced a series of inter- mediate forms culminating in the elaborate stromata and sunken perithecia of the highest species. There is, in fact, a marked parallelism between the Sphaeriales and Hypocreales, and it is by no means clear that the colour and texture of the stroma and perithecium walls are of sufficient im- portance as criteria of relationship to justify their separation, nor is it indicated that the members of the families Nectriaceae or Hypocreaceae resemble one another more closely than the numerous Sphaeriales, though these are dispersed among a series of eighteen or nineteen families. The method of classification is however conyenient, and considerably more knowledge will be required before a natural system of classification can be elaborated. In the meantime, the subdivisions of the Sphaeriales rest on the structure and development of the stroma, the form of the ostiole, and the colour and septation of the spores. As in the Hypocreales, various sorts of accessory fructifications are present. In the first eight families of the Sphaeriales the perithecia are more or less free, though they may be partly sunk in the substratum, or in a weft of hyphae, or may be seated on.a definite stroma. In the remaining ten families the perithecia are immersed either in the substratum, or in a stroma which may reach considerable elaboration. The most important of the eighteen families of the Sphaeriales are: Perithecia free Peridium membranous ostiole beset with long hairs often elaborately coiled or branched CHAETOMIACEAE, ostiole without long hairs; mainly coprophilous SORDARIACEAE. Peridium leathery or carbonaceous short neck SPHAERIACEAE. long, sometimes filiform neck CERATOSTOMATACEAE. Perithecia embedded in substratum Perithecia immersed, upper part free ostiole round AMPHISPHAERIACEAE. ostiole elliptical : LOPHIOSTOMATACEAE, Perithecia completely immersed, ostiole only pro- jecting peridium membranous or leathery, neck short paraphyses absent MYCOSPHAERELLACEAE. paraphyses present PLEOSPORACEAE. peridium leathery or carbonaceous, neck long ©=(GNOMONIACEAE. Perithecia embedded in stroma Stroma developed within substratum, differen- tiated from it VALSACEAE. Stroma free ascospores very small, sausage-shaped and hyaline or light brown, unicellular DIATRYPACEAE. ascospores unicellular, rarely bicellular, dark brown XYLARIACEAE. Vv] SHAD RIALS 15 ut Chaetomtaceae The Chaetomiaceae occur on straw, paper, dung and other waste materials; they possess free, thin-walled perithecia beset with numerous characteristic, long hairs (fig. 112), which are often elaborately branched or coiled. On these, or on the ordinary vegetative mycelium, conidia are produced. An ostiole is lacking in Ch. fimete, presumably the most primitive member of the genus; in the remaining species it is present and the peri- thecium is of the typical sphaeriaceous form. In Chaetomzum spirale the cells of the mycelium contain each a single nucleus, the archicarp arises as a coiled branch and divides into four or more uninucleate cells. There is no sign of an antheridium. Vegetative hyphae grow up from the stalk of the archicarp, and from the filament on which it is borne, and form a sheath, the outer cells of which are prolonged as hairs. Small pyriform conidia are abundant. Ch. Kunzeanum shows a very similar archicarp (fig. 113), but here the cells, as described by Vallory for the variety ch/orznum, each contain several nuclei which are often found approximated in pairs. This arrangement is reported to be as common in the vegetative mycelium as in the cells of the archicarp, and is doubtless a result of rapid division. Nii NY Fig. 112. Chaetomium pannosum Wallr.; x 50; Fig. 113. Chaetomtum Kunzeanun W. Page del. Zopf; archicarps; after Oltmanns. 156 PYRENOMYCETES [CH. In due course the archicarp becomes surrounded by a sheath of vegetative hyphae within which its growth is continued so that a mass of cells is pro- duced from which asci at last arise. In the meantime the sheath becomes differentiated into an outer coat of relatively large, brown-walled hyphae, and an inner layer of smaller cells which become narrow and elongated. As development proceeds a cavity appears within the perithecium, usually just above the ascogenous cells, and branches from the lining mycelium grow out to form the periphyses; paraphyses are not produced (fig. 114). The ripe spores are shed into the cavity of the perithecium, and do not reach the exterior immediately on leav- ing the ascus. In addition to the above, two or three otherspecies have been examined, and show the same type of archicarp and of perithecium, but in no case has any further cytological detail been worked out. The uninucleate species in particu- AG p\\ lar would probably repay investigation NN . : = Fig. 114. Chaetomium Kunzeanum Zopf; and special SOUS ought to be 5 ven perithecium, x 200; after Zopf. to the septation of the archicarp and to the number of cells from which ascogenous hyphae originate. CHAETOMIACEAE: BIBLIOGRAPHY 1881 Zopr, W. Zur Entwickelungsgeschichte der Ascomyceten. Chaetomium. NovaActa Acad. C. Leop.-Carol. G. Nat. Cur. xlii, p. 199. 1887 OLTMANNS, F. Ueber die Entwickelung der Perithecien in der Gattung Chaetomiumt. Bot. Zeit. xlv, p. 193. 1907 DANGEARD, P. A. Recherches sur le développement du périthéce chez les Ascomy- cétes. Le Botaniste, x, p. 329. 1911 VALLORY, J. Sur la formation du périthéce dans le Chaetomium Kunzeanum Zopf. var. chlorinum Mich. Comptes Rendus, cliii, p. 1012. Sordariaceae The Sordariaceae are mainly coprophilous; their perithecia are typically free, sometimes superficial, sometimes so deeply embedded in the substratum that little more than the neck protrudes from it. The genus yfocopra is exceptional in possessing a small stroma in which the perithecium is immersed, but it resembles Sordaria in all other points. The present family differs from the Chaetomiaceae in bearing only short filaments instead of v] SPHAERIALES 157 long hairs around the ostiole, and from the Sphaeriaceae in the habitat and type of spore. The mycelium is in most cases composed of multinucleate cells, but in Podospora hirsuta the cells are uninucleate (fig. 115), recalling the condition in several species of Chaetomzum. The commonest type of archicarp is a stout, coiled, septate hypha which soon becomes surrounded by vegetative filaments; it is usually terminal, but is occasionally intercalary, for instance in Sordaria fimicola. Dangeard has found a straight archicarp (fig. 115) in Sordarza macrospora, and in 1868, for S. fimiseda, \Woronin described an archicarp with a swollen terminal cell recalling the oogonium of Humaria granulata. o-- aS Fig. 115. Lodospora hirsuta Dang., archicarp; after Dan- Fig. 116. Sordaria macrospora Auersw.; a. straight archicarp ; after geard. Dangeard. In Sforormia intermedia the perithecium is initiated by the enlargement of a multinucleate mycelial cell which is often intercalary. It undergoes not only transverse but also longitudinal divisions, forming a pseudoparen- chymatous massof uninucleate cells(fig. 117), with which various neighbouring cells anastomose. The mass thus formed is responsible for the whole contents of the perithecium, though the outer walls may be formed by ordinary vegetative hyphae. In view of this fact it seems doubtful whether the initial cell should here be regarded as an oogonium, that is to say as having at one time had a sexual significance, and not rather asa preliminary stage in the development of such a mass of hyphae as initiates the apogamous perithecium af CZaveceps and its allies. In some of the Sordariaceae each : Fig. 117. Sforormia intermedia Auersw. ; initial spore is surrounded by a layer of cells of perithecium ; after Dangeard. 158 PYKENOMY CEES (Gre mucilage (Sordaria macrospora, S. fimicola, etc.), in others (fig. 2 e) one or two appendages are produced (S. jimiseda, S. coprophila, Podospora anserina, etc.). These may be gelatinous and derived wholly or partly from the epi- plasm apparently much as the ordinary thickening of the spore wall is derived, or they may form part of the young spore. In the latter case they are at first rich in protoplasm, but later most of their contents pass into the middle portion of the spore, which becomes ovoid, and the appendage is cut off by a wall (.S. g/odosa). Both types of appendage may occur on the same spore. They are sometimes hooked and they become twisted together and serve to attach the spores one to another. The uppermost appendage appears, in some cases at any rate, to become fastened to the tip of the ascus (5S. Brefeldit. SORDARIACEAE: BIBLIOGRAPHY 1883 Zopr, W. Zur Kenntniss der anatomischen Anpassung der Pilzefruchte an die Funktion der Sporentleerung. Zeitschr. fiir Naturwiss. iv; ii, p. 540. 1886 WORONIN, M. Sfhaeria Lemaneae, Sordaria fimiseda, Sordaria coprophila und Arthrobotrys oligospora. Beit. zur Morph. und Phys. der Pilze, iii, p. 325. 1901 MASSEE, G., and SALMON, E. Researches on Coprophilous Fungi. Ann. Bot. xv, ps 315: 1907 DANGEARD, P. A. Recherches sur le développement du périthéce chez les Ascomy- eetes. Le Botaniste, x, p: 333: 1912 WOLF, F. A. Spore Formation in Podospora anserina, (Rabh.) Wint. Ann. Myc. 3% ]Oh (Cr Sphaertaceae The perithecia of the Sphaeriaceae are superficial, and are borne singly or in groups; the peridium may be smooth or beset with hairs or spines. The papillate ostiole distinguishes this family from the succeeding forms with free perithecia. The majority are saprophytic on plant remains, frequently on wood; some are parasites, such as the species of Coleroa (fig. 118), which occur on the leaves of Potentella, Rubus, and other flowering plants. Rosellina quercina, the oak root fun- gus, attacks the roots of oak seedlings; the hyphae enter the living cells of the cortex and pith; they are at first hyaline, later dark in colour, and become twisted together into strands, the so-called rhi- zoctonia; these attack the roots of neigh- bouring oak plants, wrap a weft of hyphae Fig. 118. Coleroa Potentillae (Fr.) Wint.; about them and enter their cells. The perithecia, x 192. fungus may form black, chambered scle- v] SPHAERIALES 159 rotia which originate in the cortex of the host root; reproduction is by means of conidia formed in summer on the surface of the soil, and further by ascospores produced in perithecia. Hartig has found that the perithecium is initiated by the development of a pair of thick hyphae rich in contents. These become enclosed within a mass of vegetative tissue, but their subse- quent behaviour has not been determined, and no details of development are known either here or in other members of the family. SPHAERIACEAE: BIBLIOGRAPHY 1880 HARTIG, R. Der Eichenwurzeltodter Rose//ina guercina. Untersuch. aus der forst- botanische Inst. zu Miinchen iii, p. 1. Ceratostomataceae The Ceratostomataceae resemble the Sphaeriaceae in most of their characters; they are distinguished by the elongated neck of the perithecium, which is often drawn out to form a delicate hair-like process. The method of liberation of the spores in this family presents an interesting problem, but neither that question nor the development of the perithecium has yet been elucidated. Amphisphaeriaceae In the Amphisphaeriaceae the young perithecium is sunk in the substra- tum; as it matures it becomes more or less free, though in contrast to the con- dition inthe Sphaeriaceaeand Ceratostomataceae, its base isalways immersed. Development has been studied ina species of Zeéchospora anda species of Teichosporella, now both included under the genus Sz¢rzckeria, charac- Ser terized by its muriform spores. The spore produces numerous germ-tubes which give rise to a mycelium of multinucleate cells; certain cells increase in size and be- come both transversely and longi- tudinally divided till a parenchy- matous mass is produced (fig. 119). Other vegetative hyphae may form / a a scanty investment, but often the perithecium develops without this addition. Asci appear as large uninu- cleate cells, and the tissue around them disorganizes. The outer hy- Fig. 119. Strickeria sp.; initial cells of ascocarps ; phae become hard and dark only after Nichols. when the perithecium approaches maturity. 160 PYRENOMYCETES - fer The type of development here is very similar to that already described for Sporormia; it seems very doubtful whether the initial cell of the peri- thecium should be regarded as an oogonium, or whether the development is purely vegetative. The peculiarity in either case is the formation of the bulk of the perithecium from a single cell instead of, as in the majority of forms, from a complex of interwoven hyphae differentiated into sexual and vegetative components. AMPHISPHAERIACEAE : BIBLIOGRAPHY 1896 NicHots, M. A. The Morphology and Development of certain Pyrenomycetous Fungi. Bot. Gaz. xxii, p. 301. ; Lophiostomataceae The perithecia of the Lophiostomataceae are borne singly; during de- velopment they are embedded in the substratum, and they may so remain or may become partially free at maturity. There is no stroma, and the peridium is black and brittle. So far there is a close resemblance to the Amphisphaeriaceae, but the Lophiostomataceae are distinguished by the form of the ostiole, which is very large and laterally compressed, so that in external appearance they approach certain of the Hysteriales which in many cases they further resemble in their habitat on vegetable remains such as wood and bark. None of the species has been investigated in detail. M: ‘ycosphaerell aceae The Mycosphaerellaceae are parasitic forms occurring usually on leaves and giving rise to various kinds of leaf-spot. The perithecia are sunk in the substratum and develop either under the cuticle or beneath the epidermis, breaking through at maturity. The ascospores are usually septate, frequently bicellular and sometimes dark-coloured; except in the transitional genus Stigmatea, paraphyses are not developed. In several cases the formation of the perithecia is preceded by a conidial stage. Mycosphaerella nigerristigma forms pycnidia on the living leaves of Prunus pennsylvanica and perithecia after the leaves have fallen. A tri- chogyne like that of Polystigma has been recorded; it degenerates, leaving a basal cell, but whether this functions is not known. MYCOSPHAERELLACEAE: BIBLIOGRAPHY 1914 HiGGINs, B. B. Life-History of a new. species of Sphaerella. Myc. Centralbl. iv, Daliozs v] SEE RT AISES 161 Pleosporaceae The Pleosporaceae are saprophytes or in a few cases parasites, for the most part on seed plants but in some cases on Pteridophyta, Bryophyta or Lichens. The perithecia are immersed in the substratum, the ostiole only projecting, but they may become more or less exposed by the rupture of the covering tissues. The peridium is leathery or membranous. The genus P/eosfora includes some 225 species, several of which occur on grains and other grasses where they show biological specialization. Pleospora herbarum is a facultative parasite on the leaves of angiosperms ; the perithecium is initiated by the division of a hypha into numerous short cells from which branches grow out. The central cells, and later the basal parts of the branches, divide in various directions till an irregular paren- chymatous mass is formed. By further growth and division the mass assumes a globular shape and the central cells become elongated and differ- entiated as paraphyses. Later, asci appear, developing from the same cells as the paraphyses and each produces eight muriform spores (fig. 120). Fig. 120. Pleospora sp.; germinating spores, x 1000. Multicellular conidia also develop on branched hyphae, the terminal cells of which form the sterigmata. After the spore is shed the hypha may continue to grow, a new sterigma being formed above the old one. The name AZacrospo- rium parasiticum was formerly applied to the conidial stage of this species. The genus Venturia includes over fifty species, several of which are para- sitic on living leaves; the perithecium is immersed and the large ostiole beset with stiff hairs or bristles. The species grouped under /uszcladium among the Hyphomycetes are in some cases conidial forms of this genus, The conidia are two-celled, borne on short conidiophores arranged in groups; F. dendriticum is the cause of scab or black-spot on apples, and /. Pyrinum of a similar disease on pears. G.-V. LT 162 PYRENOMY CERES [CH. Leptosphaertia includes some 500 species characterized by the papillate or conical ostiole, usually free from hairs. The majority are saprophytes on plant remains, some are parasites on land plants, and some on the Red Algae. L. Lemaneae occurs on the thallus of various species of Lemanea (fig. 121). The mycelium consists of uninucleate cells and ramifies in the intercellular spaces of the host, sending branched haustoria into the cells. Here and there the hyphae are dilated (fig. 122 a, 6), and in these regions show denser and more refractive contents than usual. Fusion takes place between the dilated portions (fig. 122¢, a) which may be terminal or intercalary, and there is Fig. 121. Leplosphacria Lemaneae (Cohn) Fig. 122. Leptosphaerta Le- Brierley; transverse section through thal- maneae (Cohn) Brierley; lus of Lemanea, showing perithecium, a. 6. c. d. stages of fusion x 125; after Brierley. between dilated hyphae ; after Brierley. evidence that the nucleus of one of the swollen cells passes across into the other, which may therefore be termed the oogonium, and fuses with its nucleus. The oogonium then divides to form a number of multinucleate cells from which ascogenous hyphae arise. The nuclei in these hyphae are paired and the usual fusion takes place in the ascus. From the cells adjoining the oogonium the delicate hyphae of the sheath grow up. The morphology of the sexual organs in this genus is quite unusual, but they may perhaps best be compared with the dilated cell observed by Dangeard in the initiation of the perithecium in Sforormia intermedia; in that case, however, there does not appear to be a functional antheridium, and vegetative cells as well as ascogenous hyphae are stated to develop from the initial cell; the resemblance demands further investigation. v] SEH ABRKIALES 163 The family is rich in conidial forms, and it is probable that several species of Fungi Imperfecti, including the pycnidial genera Phoma and Hendersonia and also Cercospora, a form with long septate conidia on free conidiophores are stages in the development of members of the Pleosporaceae. PLEOSPORACEAE: BIBLIOGRAPHY 1886 WORONIN, M. Sfhaeria Lemaneae, Sordaria fimiseda, Sordaria coprophila, und Arthrobotrys oligospora. Beit. zur Morph. und Phys. der Pilze, iii, p. 325. 1889 MIYABE KINGO. On the Life History of Wacrosporium parasiticum, Thim. Ann. Bot. ili, p. 1. 1913 BRIERLEY, W. B. The Structure and Life History of Leptosphaeria Lemaneae (Cohn). Mem. and Proc. Manchester Lit. and Phil. Soc. lvii, 2, p. 1. Gnomontaceae The Gnomoniaceae are for the most part saprophytic on the leaves or other parts of plants. The perithecia are embedded in the substratum from which their long necks project. The ascus is characterized by a thickened apex through which a canal allows the exit of the spores. The spores are hyaline and paraphyses are usually not developed. The family differs from the Plecsporaceae in the long neck of the perithecium and the thickened apex of the ascus. There is no stroma, and this fact, as well as the dark colour, distinguishes Gromonza from the similar genus Polystzgma among the Hypocreales. Guomonia erythrostoma is the cause of an epidemic disease known as cherry-leaf-scorch, which attacks the foliage of Prunus avium and of several varieties of the cultivated sweet cherry. The mycelium ramifies on the leaf and runs back to the base of the petiole, where it prevents the formation of the absciss layer. In consequence the infected leaves do not fall, but remain hanging on the branches; they are the only source of infection in the following summer, and their destruction is therefore a sure method of checking the disease. Infection usually takes place in June; towards the end of August spermo- gonia appear; they are shallower than those of Polystigma, but otherwise very like them, with a wall of closely compacted hyphae and a small circular ostiole opening on the under surface of the leaf. The spermatial hyphae are narrow and tapering, and their extremities are abstricted to form the sper- matia, each of which contains a long threadlike nucleus and a relatively small amount of cytoplasm. Soon after the spermogonia have begun to develop certain hyphae near the lower epidermis of the leaf become entwined to form more or less spherical coils, the primordia of the ascocarps. Their apices project in groups of four or five through the stomata, and the terminal cells become io 164 PYRENOMMCE Es [Cre swollen and apparently mucilaginous; these projecting filaments were re- garded by Frank as trichogynes, but more recently Brooks has found evi- dence that they arise from the outer cells of the perithecium and that, what- ever their origin, they now no longer function as receptive structures. Sper- matia are often found attached to their terminal cells, but, in view of the enormous number of spermatia liberated on the under surface of the leaf, they could hardly fail to be found in relation to any projecting filament. In the lower part of the coils certain cells become differentiated by their denser cytoplasm and larger nuclei, and no doubt represent the oogonial regions of the archicarps. No union of nuclei has however been observed in them and it is at least doubtful whether they give rise to the ascogenous hyphae. The latter do not become clearly differentiated till the oogonial cells have disappeared ; asci are formed either from the terminal or sub- terminal cells; in the young ascus two nuclei fuse. Throughout the divisions in the ascus and in the division of the spore nucleus Brooks has reported four chromosomes. Those in the first division in the ascus are short and thick, resembling heterotype chromosomes in appearance, and there seems reason to believe that reduction occurs at this stage. The life-history of Gxzomonza shows many points in common with that of Polystigma; both are at first leaf parasites, and complete their develop- ment saprophytically on the dead leaf. Both produce spermogonia with filiform spermatia and perithecia developed in relation to coiled archicarps. An important point of difference is that in Polyst7gma a stroma is formed and the fungus hibernates on the fallen leaves below the tree without being injured by their decay; in Gzomonia no stroma is present and the fungus inhibits the formation of the absciss layer so that the withered leaves remain on the branches and provide a matrix in which the perithecia can be formed. GNOMONIACEAE: BIBLIOGRAPHY 1886 FRANK, B. Ueber Gromonia erythrostoma, die Ursache einer jetzt herrschenden Blattkrankheit der Siisskirschen im Altenlande, nebst Bemerkungen iiber Infection bei blattbewohnenden Ascomyceten der Baume iiberhaupt, etc. Ber. der deutsch. Bot. Gesell. iv, p. 200 1910 BROOKS, F. T. The Development of Gzomonia erythrostoma, the Cherry-Leaf-Scorch Disease. Ann. Bot. xxiv, p. 585. Valsaceae The perithecia of the Valsaceae are produced frequently in compact groups on a black stroma from which their long necks alone project. The stroma is very variable in form ; it is developed within the substratum and more or less differentiated from it, sometimes indicated only by a black stain on the wood or bark of the host and by a black margin, sometimes v] SPHAERIALES 165 extended as a thin black layer over a considerable area and ending irregularly ; sometimes, as in species of Va/sa, forming black cushions erumpent through the bark of the host. In a few cases the stroma surrounds only the upper part and not the base of the perithecium, and we have thus a transition from the rudimentary stromata of some of the earlier families. The peridium is black and leathery, the asci usually long stalked, the spores uni- or multicellular, and hyaline or dark-coloured. Conidia are frequently present, borne on free conidiophores or produced within pycnidia. The genus Va/sa includes some four hundred species and Diaporthe a rather larger number. The majority are saprophytic on wood and other re- sistant parts of plants. Diatrypaceae In the Diatrypaceae the stroma is developed under the bark of the host, and forms either a cushion or a thin, flat layer which later becomes exposed. Conidia of various kinds are produced, but the conidial and perithecial stromata are often distinct and whereas the latter are of the usual dark colour and carbonaceous consistency the former are frequently light-coloured and fleshy. This separation and the usually unicellular, small, hyaline, curved ascospores are the principal characters of the family. The genus Calosphaeria is exceptional in lacking a perithecial stroma; its perithecia are free and it could appropriately be placed in one of the groups near the Pleosporaceae but that a conidial stroma is present and closely resembles that of the Diatrypaceae; the ascospores, moreover, are of the characteristic curved form, so that Calosphaeria may, it appears, more fitly be regarded as a reduced member of the group. The species of Cado- sphaeria, \ike the other Diatrypaceae, occur chiefly on dead wood but C. princeps infects the living branches of cherry, plum and peach. In Diatrype the most characteristic stroma is a black corky tissue of indefinite extent in which the perithecia are completely immersed ; the ascus contains eight spores in contrast to the numerous spores of certain species of Calosphaeria and of Diatrypella, a genus further distinguished by the cushion- shaped stroma. AX ylariaceae The Xylariaceae occur chiefly on wood; they represent the highest development of the Sphaeriales and are characterized by the free superficial stroma which is cnly very rarely, as in Hyfoxylon, partly sunk in the sub- stratum, and shows every variety of form from a spreading crust on the surface of the host, as in the genus Mammularia, some species of which 166 PYRENOMYCETES (ern approximate Déatrype, to the almost spherical cushions of /ypoxylon (fig. 123) and the erect, simple, or branched stromata of Xy/arza (fig. 124) and its allies. The perithecia are arranged just below and at right angles to the surface of the stroma; their development may be preceded by the formation of conidia which often cover the young stroma with a whitish powder, Fig. 123. Aypoxylon coccineum Bull.; the smallest stroma bears conidia, the others perithecia ; after Tulasne. Poronia punctata occurs on old horse dung; the stromata are about I1cm. in height, stalked and expanded above into a cup or disc (fig. 125), which, in the earlier stages of development, is covered by a greyish-white film of conidia; later the ostioles of the numerous perithecia appear as black dots scattered over the surface of the disc (fig. 126). The asci, when ripe, protrude through the ostiole so that the dark brown spores are shed outside the perithecium. Dawson was able readily to obtain pure cultures, both from the asco- spores and from the conidia, on 10 per cent. gelatine made up with decoction of horse dung. The ascospore forms a single lateral germ-tube, which develops septa and branches freely. The conidia produce germ-tubes from either end or from both and sometimes also laterally; the mycelium is at first much more delicate than that derived from the ascospores but soon becomes indistin- guishable from it. Branches arise from points just below the cross walls; v] - SPRAERIALES 167 frequent lateral anastomoses occur and crystals of calcium oxalate, which have become separated from the substratum, are found among the filaments. Hyphae become massed together to form the stroma which in the very young stages consists entirely of vegetative filaments densely inter- Fig. 124. Xylaria Hypoxylon Grev., after Tulasne. woven and rising vertically from the surface of the substratum. As they grow the stromata assume their characteristic shape, conidia appear and ‘drops of pinkish or yellowish fluid are exuded. When these dry up, black dots indicating the position of the ripening perithecia are seen. 168 PYRENOMYCETES a Fig. 125. Poronia punctata (L.) Fr.; a. surface, 6. lateral view; after Tulasne. Fig. 126. Poronia punctata (L.) Fr.; stroma cut across; after Tulasne. [eRe ~~ ae Te a Vv] SPHAEREALES 169 The perithecium is initiated by the development of a coil of large, deeply-staining cells forming the archicarp. It arises amongst the vegetative filaments of the stroma, forms a couple of loops and is continued towards the surface of the stroma as a slender multicellular trichogyne (fig. 127 @). At an early stage the coiled portion becomes surrounded by a knot of small, densely-staining hyphae; later the trichogyne disappears, degeneration progressing from the base to the apex; the investing filaments grow more actively on the side of the archicarp towards the surface of the stroma, so that the young perithecium becomes pear-shaped (fig. 127 0, c); further growth renders it hollow, and the upper part becomes lined with delicate periphyses (fig. 127d). At the base of the developing perithecium is a group ence MSA oat AS IS\SZZZ XR WY (7 Gud Nae J NX Wes . F, é SS Fig. 127. Poronia punctata (L.) Fr. ; a. archicarp, x 2753 b. c. and d. young perithecia, x 205; after Dawson. of stout, deeply-staining hyphae, from which the asci arise and which occupy the position of the coiled archicarp in earlier stages. Later the base and sides of the perithecium are covered by numbers of filiform, septate para- physes, and amongst these the asci develop. It seems pretty clear that the trichogyne now no longer functions; this is borne out by the fact that degeneration proceeds from its base upwards and not from its apex, as might have been expected if a male nucleus were travelling down. It is probable, though it has not actually been demon- strated, that the ascogenous hyphae are derived from the archicarp, but in view of the complete degeneration of this organ in Gzomonza, it is not safe to conclude without further evidence that it is still functional in Povonza punctata. The species deserves further investigation, especially from this point of view. In both Yylaria and Hypoxylon the young stroma is covered by a tangle 170 PYRENOMYCETES [cH. of conidiophores, from which small oval conidia are abstricted. In Xylarza these form a white coating, in marked contrast to the older black portions of the stroma, where the perithecia are maturing, and justify the name candle-snuff fungus, applied to some of the commoner species. If, in either genus, the stroma be sectioned during the conidial stage, nests of small hyphae, similar to those in Poronza, will be found, and are the first indica- tions of the perithecia. Sometimes a stouter hypha with larger nuclei, presumably an archicarp, is recognizable (fig. 128), but it has not been shown to function, and there is no evidence of normal sexuality. It is however not unlikely that some of these species, which are conveniently easy to microtome, will repay further investigation. Ata later stage ascogenous hyphae are readily recog- nizable (fig. 129). ; Fig. 128. Xylaria polymorpha (Pers.) Grev.; archicarp embedded in Fig. 129. Xylaria polymorpha (Pers.) Grev.; septate stroma, X 1000. archicarp, X 1000. XYLARIACEAE: BIBLIOGRAPHY 1861-5 TULASNE, L. R.andC. Selecta Fungorum Carpologia; Imperial-typograph., Paris. 1900 Dawson, M. On the Biology of Poronia punctata (L.). Ann. Bot. xiv, p. 245. q v] . LABOULBENIALES 171 LABOULBENIALES The group Laboulbeniales includes some six hundred species arranged in over fifty genera. All are minute external parasites on insects, chiefly on members of the Coleoptera. They appear to do but little injury to the host, inducing at most a slight irritation but never causing death, indeed their own existence depends on that of the insect to which they are attached since, unlike many other fungi, their life ends with that of their host. The Laboulbeniales are all of fairly simple structure (fig. 130) and show an underlying similarity of type. In all cases the vegetative part consists of a receptacle, usually two-celled, attached to the integument of the host by a blackened base or foot. From the receptacle grow out filamentous appen- dages on or among which the male organs are produced and, with a few exceptions, the receptacle of the same individual also gives rise to a female organ from which a perithecium liberating ascospores is eventually developed. The plant is covered by a thin, homogeneous membrane which is ex- ceedingly tough and impervious and is developed from the gelatinous coat of the spore; it efficiently protects the cells from desiccation. Within this envelope the cell walls (except those of the receptive parts of the trichogyne and of the internal cells of the perithecium) are very thick and laminated. In certain cases, and especially in the genus Ladoulbenta, they are traversed by fibrillae which arise from the innermost wall layer and are attached to the inner surface of the envelope. The cells are uni- nucleate (fig. 131) with rather dense, granular or reticulate cytoplasm and Fig. 131. Ladboulbenia chaetophora Fig. 130. Laboulbenia triordinata Thaxter ; x 135; young perithecium and _tricho- after Thaxter. gyne, x 360; after Faull. 172 PYRENOMYCETES [CH. contain oil globules. Between adjacent cells that have the same origin the protoplasm is continuous through broad pits. The cytoplasm on each side dips into the pit, forming a thick strand which, in Laboulbenza at least, appears to be intersected by the middle lamella (Faull). The latter in favourable cases is seen to be perforated by one or more fine pores through which com- plete continuity is established’. There is evidence that a stout strand of cytoplasm unites contiguous cells in the appendages. The spores are remarkably uniform throughout the group, being in- variably hyaline and fusiform or acicular in shape and almost invariably two-celled (fig. 132). The cells are commonly of unequal size, that nearest the apex of the ascus being the larger, and both are uninucleate. The spore is clothed in a gelati- nous sheath especially well developed about the upper end which, when the spore is discharged - from the perithecium, is destined to come in con- tact with the integument of the host. Here the gelatinous mass enables the spore to take up the oblique position in which germination occurs. The lower extremity of the spore (its apex while in the ascus) forms the foot. As a rule the gelatinous envelope in this region becomes hard, opaque, black and more or less elastic and thus, while adhering firmly to the substratum, it may give the plant a certain freedom of movement. This elasticity is found especially in forms on sub- merged and rapidly swimming hosts where it Fig. 132. Laboulbenta elon- : : ~ ate. Thaxter: ° bicellular allows the parasite to lie back along the body spore; after Thaxter. of the insect. Sometimes the foot is cut off from the rest of the plant by a wall, more often it is continuous with and forms part of the basal cell of the receptacle. In the great majority of cases it does not penetrate into the substance of the host but is in contact with the surface by a thin membrane through which materials are absorbed into its cavity. There are a certain number of forms, however, especially those occurring on soft-bodied insects or on the soft parts of others, in which a definite rhizoidal apparatus is developed and penetrates the body of the host. These species show no greater vegetative luxuriance than other members of the group and apparently do not benefit by their more elaborate absorptive organ. The receptacle, like the foot, develops from the lower segment of the spore. It consists, in the simplest cases, of two superposed cells and (in ‘A similar type of pitting has been described by Kienitz-Gerloff for the Red Algae (‘*Neue Studien ber Plasmodesmen,” Ber. d. deut. bot. Gesel. XX, 1902.) v] LABOULBENIALES 173 monoecious forms) bears the appendages in a terminal position and the perithecium laterally (fig. 136). More rarely the receptacle consists of a larger number of cells variously arranged and reaching a considerable complexity in such forms as Zodzo- myces vorticellarius (fig. 133). One or more appendages are borne on the receptacle. These are more or less filamentous and often elaborately branched. They bear the male organs and serve also for the protection of the delicate trichogyne and perhaps facilitate fertilization by holding a drop of water around the organs con- cerned. The primary appendage is developed from the upper segment of the germinating spore and is terminal; the later formed secondary append- ages, when present, are outgrowths from the cells of the receptacle. The male element is a non-motile cell which as early as 1896 was homologized by Thaxter with the spermatium of the Red Algae. The latter organ has now been shown to be an antheridium?! in which the nuclear divisions are reduced to one, or have altogether disappeared ; it is liberated entire from the male plant and carried passively to the female organ. It seems very probable that in the simplest cases, where they are produced externally at the tips of more or less specialized branches (fig. 134), Fig. 134. Cevatomyces rostra- Fig. 133. Zodiomyces vorticellarius Thaxter ; after tus Thaxter; exogenous Thaxter. spermatia ; after Thaxter. 1 Wolfe, Ann. Bot. xviii, 1904. Yamanouchi, Bot. Gaz. Ixii, 1906. 174 BYRENOMYCETES [CH the “antherozoids” or spermatia of the Laboulbeniales have the same signi- ficance as those of other fungi. They fall off when mature and the cells from which they were formed may give rise to others in the same position. In Coreomyces instead of a segment of the branch being detached to form the spermatium, a portion of its contents is extruded. This arrangement leads to the more specialized endogenous organ which is found in S#zgma- tomyces (fig. 136) and in many other forms. Here the naked mass of proto- plasm cut off from the parent cell may be regarded as the homologue of the spermatium, or the parent cell may be recognized as an antheridium and the detached segments as non-motile spermatozoids. They function, in any case, as sperms or male elements. They are detached from the contents of a flask-shaped cell and are extruded through an elongated neck opening at maturity to the exterior. Between the neck and the venter a diaphragm of cellulose is deposited and is perforated by a narrow opening so that the sperms are nipped off as they pass into the neck. They are uninucleate, the nucleus of the parent cell undergoing successive divisions so that a series of sperms are produced. The parent cell has been termed an antheridium but if the spermatium is antheridial in character the name cannot appropriately be used for the cell in which it is borne, though the term spermogonium is applicable. These sperm-forming organs may be produced singly or in groups, each with its neck opening independently to the exterior, or they may form com- pound structures (fig. 135), the necks of several cells penetrating a single adjacent cell into the cavity of which the sperms are discharged and from which they escape by a common duct, the so-called secondary neck, which may be a mere extension of the cell forming the common cavity or, in a few cases, may involve other cells also. The individual sperms are formed in much the same way in the compound as in the simple organs, but instead of being cut off from the parent mass of protoplasm by a diaphragm at the base of the primary neck they remain attached till the neck widens abruptly at its end, and they are extruded into the common chamber. Hundreds, or even thousands, may be formed during the period of activity of a single compound organ. The exo- genously produced sperms are always walled where- Fig. 135. Dimeromyces Afri- as those formed endogenously are naked when first canus Vhaxter; compound = 4 spermatial organ; after set free; later a thin wall may be secreted. Uhaster, The female organs are formed from the basal cell of the spore and are thus necessarily lateral. This condition is often obscured in the mature plant where the developing perithecium may push v] LABOULBENIALES | 175 the appendages aside and take up an apparently terminal position. The development is very uniform, and has been described by Thaxter in some detail for Stigmatomyces Baert. Here, the upper cell of the receptacle divides into two; the lower of these remains as part of the receptacle, and the upper grows out (fig. 136a@) to form the female organ and ultimately Fig. 136. Stigmatomyces Baert Peyritsch; development of the perithecium; a. shows the two-celled . receptacle, a single appendage bearing five simple, endogenous spermatial organs, and the beginning of the perithecium ; 4.—2. indicate successive stages in the development of the perithecium; the trichogyne first appears in @.; in e. spermatia are being shot out and some are attached to the trichogyne; in z. two of the four ascogenous cells are shown, with the superior sterile cell above them, and the primary and secondary inferior sterile cells below; after Thaxter. the perithecium. It divides transversely ; the upper of its daughter cells gives rise to the female organ, the lower divides several times (fig. 1366), and ultimately forms the double wall of the perithecium, a function fulfilled by a complex of neighbouring hyphae in Ascomycetes with a richer vegetative development. The upper cell, the initial of the female organ, divides, separating the female cell below (fig. 136c) and a cell above, which divides once more to form the terminal trichogyne and the subjacent trichophoric cell (fig. 136 2). 176 PYRENOMYCETES [CH. All the cells are uninucleate. The female cell is called by Thaxter a carpogonium or carpogonic cell in conformity with the term used for the Red Algae, but it obviously corresponds to the cell in which fertilization is now known to occur in other Ascomycetes and will therefore here be termed the oogonium. In Stigmatomyces Baeri the trichogyne is simple (fig. 136d, e) but in many other members of the group it undergoes frequent septation and branches freely. The apices of the branches are alone receptive and may straight or spirally coiled(fig. 137). However elaborate, the trichogyne quickly disappears, collapsing and breaking off as soon as its function is fulfilled. In endogenous species the sperms are shot direct on to the trichogyne or carried to it by the water which ordinarily surrounds these filaments when the hosts are hiding in moist places. In Zodzomyces on the other hand, where the spermatia are formed externally, they fall off the parent branches on to the cup-shaped receptacle, and there appear to be sought by the trichogyne which is at first bent over (fig. 138 @) and later lifts itself after a spermatium has become attached (fig. 138 0). Fig. 137. Compsomyces verticillatus Thaxter; after Thaxter. Fig. 138. Zodtomyces vorticellarius Thaxter; trichogyne a. before and 6. after attachment of spermatium ; after Thaxter. In any case numerous male cells reach the trichogyne and, though the actual process of fertilization has not yet been seen, it appears likely that it is accomplished. Afterwards the oogonium divides into three superposed cells, the sterile inferior cell, the sterile superior cell and a fertile cell lying between the two (fig. 136.¢,%). This middle cell cuts off a secondary sterile cell below (fig. 1362) which like the other sterile cells is eventually destroyed. It then divides longitudinally into four “ascogenic” cells, two of which are shown in vy] LABOULBENIALES 177 fig. 1362, and from these asci bud out, arising in a more or less distinctly double row (fig. 139 @). Some variation occurs in different species in the later divisions and in the number of ascogenic cells. In Polyascomyces (fig. 140) more than thirty are present, covering a basal area from which numerous asci bud upwards, so that the condition approximates that in other Ascomy- cetes. Faull describes the ascogenic cells as binucleate, each containing two Fig. 139. Stigmatomyces Baert Peyritsch; a. young Fig. 140. Polvascomyces Tricho- asci; 6. ascus containing four spores; c. mass of phyae Thaxter; after Thaxter. spores in perithecium ; after Thaxter. nuclei which undergo conjugate division whenever an ascus is formed. As a result the young ascus is binucleate and nuclear fusion followed by three divisions takes place in the usual way. As a rule four only of the eight nuclei function; the spores are produced in a manner quite characteristic of the Ascomycetes generally. In the ascus they are usually disposed more or less definitely in pairs and the members of a pair are discharged together from the perithecium and germinate side by side. In monoecious species one member of a spore pair may frequently produce a smaller and weaker individual than the other, while in Labouwlbenia wnflata the atrophy of one at an early stage of development is a regular phenomenon. In Stigmatomyces Sarcophagae the smaller individual is uni- sexual, producing only male cells, while the larger is hermaphrodite (fig. 141). In dioecious species the paired spores are of rather different sizes. The smaller spore gives rise to a male plant, the larger to a female, so that by their association at a point of contact with the host a condition essential for the perpetuation of such species is secured. The cytological changes by which this segregation of sex is brought about between the members of a pair should be of great interest and demand investigation. CHV. 12 178 PYRENOMYCETES [CH. There is an obvious suggestion in these phenomena of a transition between the monoecious and dioecious condition but it is not clear in which direction the series should be read. It might be inferred that the male plant had become atro- phied after the female had acquired spermatial organs, or on the other hand that, as in many other groups of plants, a hermaphrodite con- dition was primitive and segregation a later development. Amorphomyces Falagriae may be taken as an example of a dioecious form which shows also several other peculiarities. The spores are unique amongst those of Laboulbenialesin being aseptate (fig. 142). The difference between the spores producing male and female plants is slight at first but becomes very apparent on germi- nation. In each case the spore divides into three superposed cells (fig. 143 @), in the male the terminal cell elongates and forms a single male organ liberating endogenous sperms. The second cell may be regarded as the basal cell of this struc- ture and the lowest as a unicellular receptacle, or they may be held to constitute together a two-celled receptacle. There are no appendages. In the female the lowest cell, which may become partly divided, forms the receptacle, the next above gives rise to the perithecial wall and the terminal cell to the female organ proper. The perithecium and its contents are therefore here terminal, a state of affairs not met with elsewhere in the group. The terminal cell divides in the usual way to form an oogonium, a tricho- phoric cell and a trichogyne; the latter is short and branching (fig. 1430). The development of the perithecium (fig. 144) seems fairly typical and the asci apparently contain four spores. Fig. 141. Stigmatomyces Sarco- In 1912, Faull published an account of the phagae Thaxter; male and her- ‘ : maphrodite individuals, x 260; Cytology of two species of Ladboulbenta, L. chaeto- after Thaxter. phora, and L. Gyrintdarum. Both occur on the same host, and could not be distinguished in the young stages. Both are > > D> parthenogenetic, no male cells being formed. ate v] LABOULBENIALES 179 A trichogyne, trichophoric cell and oogonium are formed in the usual way (fig. 131). According to Faull nuclear division takes place both in the oogo- nium, and in the trichophoric cell, and the partition between these two breaks down so that a long cell containing a row of four nuclei is formed (fig. 145 a). Fig. 142. Amorphomyces Fala- griae Vhaxter; paired spores ; Fig. 143. Amorphomyces Falagriae Thaxter; male and after Thaxter. female individuals; a. young, 6. mature; after Thaxter. Walls cut off the upper and the lower nucleus, and a central binucleate cell is left, the lower nucleus of which is presumably a daughter of the oogonial and the upper of the trichophoric nucleus. These divide simultaneously and a binucleate inferior sterile cell is separated from the binucleate fertile cell. This in turn divides to form the ascogenic cells, from which the asci are to develop, and these and the asci which they produce are therefore binucleate. The two nuclei in the ascus fuse and their union is regarded by Faull as the only nuclear fusion which occurs in this very curious life history. Meiosis then takes place, followed by the third division. The upper daughter nuclei of this division degenerate and around the lower nuclei spores are organized. In each spore the nucleus divides once and a transverse septum is formed. Faull describes four chromosomes (fig. 145 ¢) at every stage but figures an apparently larger number in eS Fig. 144. Amorpho- the first division in the ascus where the structures repre- myces Falagriae sented are evidently gemini (fig. 145 7 Rear ange aan > gs. 145 )- female individuals, the latter with peri- . . . es G The Laboulbeniales are subdivided by Thaxter ac- Ce ou ee cording to the method of formation of the male cells, ter. = Ny Ny 180 PYRENOMYCETES [CH. whether exogenous or endogenous, and in the latter case whether produced in simple or compound organs. In this way three families, Peyritschiel- laceae (compound endogenous), Laboulbeniaceae (simple endogenous) and Ceratomycetaceae (exogenous) are distinguished. Fig. 145. Laboulbenia chaetophora (2). a. cell formed by binucleate oogonial and trichophoric cells, x 430; 9. first division in ascus described by Fauil as the anaphase, x 1510; c. nuclear division in spore, showing four chromosomes, x 2800; after Iaull. Since almost all our knowledge of the group is due to the brilliant work of Professor Thaxter of Harvard it follows that the North American species are far better known than those of other localities. Such material as he was able to obtain from warmer regions proved, however, exceedingly rich in representatives of the group, and it is probable that further study will show them to be widely distributed. The known European species are few, and only two have been identified in Great Britain. The systematic relations of the Laboulbeniales are not easy to deter- mine. They are pretty evidently monophyletic, and are highly specialized along lines dependent on their peculiar habitat. The form and develop- ment of the ascus is typical of the Ascomycetes, and the Laboulbeniales clearly belong to that group, though it is difficult to indicate their affinities within it. In the Laboulbeniales the young female branch consists of four parts, the initial cell of the perithecium wall, the oogonium (carpogenic cell of Thaxter), the trichophoric cell and the trichogyne. These correspond pretty clearly with the archicarp of other groups. The initial cell of the perithecium wall constitutes a stalk-cell from which the enveloping hyphae develop. The trichophoric cell should probably be included as part of the trichogyne, which in this sense always consists of at least two cells. After fertilization the oogonium divides to form a row of cells, which are, from below upwards, v] LABOULBENIALES 181 the inferior sterile cell, the secondary inferior sterile cell, the mother-cell! of the ascogenic cells and the superior sterile cell. The subterminal of these alone gives rise to asci ; this it does by dividing longitudinally into a definite number of ascogenic cells from which the asci are budded out. A multicellular trichogyne is not uncommon among Ascomycetes, and the division of the oogonium after fertilization into a row of cells is a well-known phenomenon occurring among Plectascales, Erysiphales, and Discomycetes. In most cases several cells of the septate oogonium give rise to ascogenous hyphae, but in the Erysiphales only the subterminal cell of the row does so. In Erysiphe this cell, which always contains at least two nuclei, gives rise to several asci and differs’ from the sub- terminal cell of the Laboulbeniales chiefly in the fact that the asci are produced from short outgrowths instead of, as in Stzgmatomyces and its allies, from daughter cells formed by longitudinal division. In this character then, the Laboulbeniales would appear most nearly to approach the Erysi- phaceae, which they also resemble in the formation of the sheath from the stalk cell of the oogonium, but they differ from them in possessing a tricho- gyne, an organ not known in that group, where the antheridium comes into direct contact with the oogonium. The Laboulbeniales and Erysiphaceae have also in common the uni- nucleate character of their vegetative cells. In the structure of their ascocarp, opening as it does by a narrow aperture, the Laboulbeniales approach most closely to the other Pyrenomycetes. The male element in the Laboulbeniales is a non-motile, uninucleate structure which may be budded off externally from the parent cell, or extruded from it as a naked mass of protoplasm. Amongst the Fungi spermatia occur in the Pyrenomycetes and Lichens and also characterize the Uredinales, but in all these cases they are budded off externally as walled structures. The spermatium both in the Red Algae and in the Fungi has been homologized with a reduced antheridium, and, as has already been pointed out, the exogenous male element no doubt bears the same significance among the Laboulbeniales. We have no satis- factory indication as to the relative primitiveness of the endogenous and the exogenous condition, but it may be noted that exogenous forms only are known among Fungi other than Laboulbeniales. The endogenous organ may be derived from the branch which cuts off exogenous, walled spermatia, or it may represent quite a different response to the need for non-motile male elements, the parent cell being the homologue of the antheridium and the fertilizing element that of a spermatozoid. These various characters, approximating to those of sometimes one, 1 This cell is described by Thaxter as the ascogonium. The word has acquired a somewhat different sense in other Ascomycetes. 182 PYRENOMYCETES [CH =v; sometimes another group of Ascomycetes, seem on the whole to indicate no very close relationship, but suggest rather that the Laboulbeniales were derived from an ancestral form, already definitely ascomycetous but not otherwise highly specialized, and that they have undergone elaborate and characteristic modifications after branching off from the main line. Their nearest affinities are with the Erysiphales and Pyrenomycetes. The resemblances between the Laboulbeniales and the Red Algae have been regarded as significant in connection with the hypothetical relationship of the higher Fungi to that group. LABOULBENIALES: BIBLIOGRAPHY 1896 THAXTER, R. Contribution towards a Monograph of the Laboulbeniaceae, Pt. I. Mem. Am. Acad. Arts and Sciences, xii, p. 195. 1908 BIFFEN, R. H. First Record of Two Species of Laboulbeniaceae for Britain. Trans. Brit. Myc. Soc. iii, p. 83. 1908 THAXTER, R. Contribution towards a Monograph of the Laboulbeniaceae, Pt. II. Mem. Am. Acad. Arts and Sciences, xili, p. 219. 1911 FAULL, J. H. The Cytology of the Laboulbeniales. Ann. Bot. xxv, p. 649. 1912 FAULL, J. H. The Cytology of Laboulbenia chaetophora and L. Gyrinidarum. Ann. Bot. xxvi, p. 325- ee CHARTER: V1 BASIDIOMYCETES THE Basidiomycetes include over 13,000 species possessing a well-developed mycelium, which, among the higher forms, builds up an elaborate fruit-body such as may be observed in the toadstools, bracket fungi and puff balls. They are characterized by the fact that their principal spores, the basidio- spores, are borne externally on the mother-cell or basidium. The young basidium contains two nuclei; these fuse, and the fusion nucleus divides twice, providing the nuclei of the four spores; each spore is formed at the end of a stalk or sterigma through which the nucleus passes to enter the developing spore. The two divisions in the basidium constitute a meiotic phase. In the Autobasidiomycetes the basidium is without septa, and the spores, except where some fail to develop, are regularly four in number for each basidium. In the Protobasidiomycetes the basidium is divided into four cells, each of which gives rise to a single spore; the walls are transverse in the Uredinales and Auriculariales, longitudinal or oblique in the Tremellales. In the Hemi- basidiomycetes (Ustilaginales) septa may or may not be present in the basidium, but the fusion nucleus divides more than twice, and more than four spores are produced. In Puccinia, Phragmidium and other Uredinales, and in Szrobastdtum and its allies, the basidia are developed in chains, in other cases they are borne singly. In the Ustilaginales and in the majority of the Uredinales the nucleus and cytoplasm of the basidium are at first enclosed in a thick wall forming the brand-spore or teleutospore cell, which becomes detached, form- ing an additional means for the distribution of the plant; later the contents are extruded as a thin-walled promycelium on which the basidiospores are produced. In other Basidiomycetes the basidia are thin-walled throughout their development and produce spores while still attached to the mycelium. The basidiospore is unicellular, round or oval in shape, usually with a smooth, rather thin wall. Echinulate or warted spores occur in a few species, and in many families, especially among gill-bearing fungi, dark or bright-coloured spores are common. In a considerable number of genera accessory spores are also produced. Except for the production of their characteristic spores externally on basidia, the Ustilaginales and Uredinales differ in almost every particular from the majority of the Basidiomycetes; they are obligate parasites with a delicate mycelium ramifying in the tissues of the host and they lack the elaborate stroma characteristic of the Autobasidiomycetes. It has therefore seemed advisable to deal with them as distinct groups, separating them for purposes of description from the Basidiomycetes proper. CEA eal Raya HEMIBASIDIOMYCETES USTILAGINALES THE Ustilaginales, Brand fungi, Smuts or Bunts, constitute a group of some 400 obligate parasites on the higher plants, giving rise in the tissues of the host to characteristic, usually dark-coloured resting-spores, the brand-spores, teleutospores or chlamydospores. These are developed in considerable quantities, either singly, in pairs, or in clusters known as spore-balls, and when ripe break through the host tissue, forming a pustule or sorus. No distortion of the host is caused during the period of vegetative growth, but in preparation for the formation of spores very considerable hypertrophy may be induced. Ustelago Treubit on the stem of Polygonum chinense in Java causes the formation of elaborate galls (fig. 146) provided with vascular tissue and growing by means of a cambium; Ustilago Maydis produces whitish swellings and blisters, often as large as a fist, on the stem, leaves, roots, and especially the flowers of Zea Mays; and Uvocystis Violaedeforms the stems and leaves of various species of Vzola. Several other smuts develop their spores in the ovary of the host plant, or infect the stamens, filling the anthers with spores and benefiting by the means of distribution provided for the pollen. OUstelago antherarum’ even induces development in the staminal rudiments of the normally pistillate flowers of Lychnzis dioica. The stamens formed undergo dehiscence as usual and differ from those of the male Fig. 146. Ustelago Treubiz Solms; stem of ‘ Polygonum with fruit gall,” nat. size; after flowers only in the presence of fungal Solms Laubach. spores instead of pollenin their anthers. In all these cases and in most of the Ustilaginales spore-formation is strictly localized, but in the genus /zz¢y/oma and its allies spores may be formed at almost any point. 1 Ustilago antherarum (DC.) Fr.= Ustilago violacea (Pers.) Fuck. cH. VII] USTILAGINALES 185 The mature brand-spore is uninucleate, and is surrounded by a delicate endospore and by an epispore which may be smooth or variously sculptured and usually contains pigment, giving the spore a black, brown, or violet colour. On germination the spore gives rise to a short tube, the promycelium or basidium (fig. 147), into which its contents pass, the nucleus undergoing at Ustilago Scabiosae Sow.; development of basidium; after Harper. least two divisions; the basidium in turn produces a number of uninucleate sporidia or basidiospores. The basidium may be unicellular, giving rise to a bunch of basidiospores at its apex (77/etia (fig. 148 a)), or multicellular, usually four-celled, producing one or more basidiospores from each cell (Us- tilago (fig. 147¢)). The nucleus of the parent cell does not travel into the basidiospore but divides, sending one daughter nucleus into the spore, while the other, remaining in the basidial cell, may undergo further divisions so that nuclei are provided for a number of spores. Under suitable conditions the basi- diospores are cut off in considerable numbers. They may further multiply by budding, giving rise to conidia, or Fig. 148. 7#dletia Tritéct (Bjerk) Wint.; a. : ; basidium thirty hours after germination of a delicate mycelium may be formed brand-spore; 4.after conjugation of basidio- from which conidia are abstricted (77/- spores; x 300; after Plowright. letia). A supply of conidia is produced by these means in dung decoction and other nutrient solutions, and no doubt in the damp, manured soil of the 186 HEMIBASIDIOMYCETES (eee fields. As a rule the conidia are of the same oblong form as the basidio- spores, but, in the genus 77//etza and some of its allies, they may be stout or sickle-shaped, whereas the basidiospores are long and narrow. In Extyloma the brand-spores are capable of germination on the tissues of the host leaf, where they give rise to hyphae which penetrate through the stomata and form basidia from which basidiospores are produced. During their development the els of the basidium, the basidiospores, or the conidia budded out from them, may become united in pairs (figs. 148 6, 149), by means of a tube of variable length put out by one or both participants and recalling somewhat the con- jugation tube of the Zygnema- ceae. The growth of these tubes is very accurately directed and appears to depend on a chemo- tropic stimulus. In the majority of cases the Fig. 149. Ustilago antherarum Fr.; a. and 6. conju- i gating basidiospores ; ¢. conjugation between acell nucleus of one of the associated of the basidium and a basidiospore; after Harper. cells passes down the tube into the other, but does not fuse with its nucleus (fig. 150). Later both nuclei divide, and a mycelium of binucleate cells is produced. It is on this mycelium that the infection of the host depends; it penetrates the tissues usually of the seedling, but sometimes of the developing parts of the mature plant, being in most cases derived from spores which adhered to the seed coat. These may be destroyed by dipping the seed into hot water or formalin solution before sowing. Once in the tissues of the host the binucleate mycelium penetrates in all directions, ramifying between the cells of the host and send- ce ing haustoria into them. The PRO internodes of the stem are tra- | versed by long, unbranched Fig. 150. Ustilago Horde’; conjugation ; after hyphae, but in the nodes branch- Lutman. ing is frequent, and here also the majority of the haustoria are to be found. Where the host is perennial the mycelium perennates in it, and, if the host dies down during the winter, remains alive but quiescent in the upper part of the root stock till the growth of new shoots in spring gives it a fresh opportunity of development. Conidia have been recorded on the parasitic mycelium of Zzburcinia and /xtyloma but are not of common occurrence at this stage. vu] USEICAGINALES 187 In the regions where the formation of brand-spores is to take place, the mycelium becomes richly branched and often swollen and gelatinous. In Ustilago and Sphacelotheca the sporogenous hyphae are divided into a number of short segments in each of which the contents form a spore surrounded by an independent membrane. The spores are enclosed at first within the gelatinous parent walls, but later these disappear so that the whole mycelium is transformed into a pulverulent mass of spores. In Tilletia and Entyloma the sporogenous cells are budded off laterally from the mycelium. In Zudburcinta a number of richly septate hyphal branches become inter- woven, forming a knot or spore-ball in which spores to the number of 50 or 100 are developed from within outwards. In Uvocystis the spore-ball is small and the outer cells remain pale or colourless and do not function as spores though they resemble them in form (fig. 151). In Doassansia the outer sterile cells are wedge-shaped, and in Sovosporium they form a gelatinous investment in which their individual boundaries are no longer recognizable. 2 wr Fig. 151. Urocystis Fischeri; spore- Fig. 152. Ostilago Carbo; a. young, binucleate ball, one spore germinating, x 500; brand-spores; 6. older spores after nuclear after Plowright. fusion; after Rawitscher. The young spore, like the cells of the mycelium from which it is derived, contains two nuclei (fig. 152@). These undergo fusion, so that the mature spore is uninucleate (fig. 152). The pairing of the nuclei, which begins with the association of the basidiospores (or their conidia), is thus completed in the brand-spore. The minute investigation of the group may be said to have begun in 1807 when Prévost recorded the germination of the spores of 77//etza Tritict. His work was continued by Berkeley, Tulasne, de Bary, the latter's pupil Fischer von Waldheim, and Brefeld. Many of these early investigators observed the union of the sporidia in 188 HEMIBASIDIOMYCETES | [cH. pairs, and, the nuclei not being identified, there was some question as to whether the process was to be regarded as sexual (de Bary), or as a merely vegetative phenomenon (Brefeld), like the formation of H-pieces and clamp- connections. In 1894 Dangeard described the fusion of nuclei in the young brand- spore, but it was not till several years later that this was correlated with the union of the sporidia and the nuclear life-history made clear. The salient points of this history are (1) nuclear association, (2) nuclear fusion, (3) germination of the brand-spore, and formation of the basidium. At this stage the fusion nucleus divides twice or oftener, and uninucleate cells are formed. This sequence of events indicates that the basidium and its spores are the starting point of a brief haploid phase, which gives way to the diploid generation when conjugation takes place. The life-history of the Ustilaginales would appear to be reduced rather than primitive, the conjugation of the spores replacing some ordinary sexual process; but the present state of our knowledge scarcely permits speculation as to what the earlier alternation of generations may have been. Tuburcinia primulicola, which has two parasitic phases, respectively uni- nucleate and binucleate, suggests closer comparison with the Uredinales than with any other investigated form. The Ustilaginales are divided into two groups, distinguished by the character of the basidium, which is septate in the Ustilaginaceae and con- tinuous in the Tilletiaceae. The two families are of about equal size, in- cluding together over 400 species. The difficulty at first experienced in classifying these fungi is indicated by the occurrence of such names as Uvedo, Caeoma, Erysiphe, Ascomyces (= Exoascus), and Lycoperdon among the older synonymy of the species. Ustilaginaceae Ustilago, with nearly 200 species, is the most important genus of the Ustilaginaceae. It is cosmopolitan, occurring on all sorts of host plants, and is characterized by the fact that its brand-spores are produced singly. Ustilago Carbo infects species of Avena, Triticum and Hordeum, the forms on the different hosts being biologically distinct. Rawitscher observed that the spores germinate readily in dilute nutritive solutions, forming a three or four celled basidium from which basidiospores may be abstricted in the usual way. More commonly, however, the basidia develop without spore- formation into branched mycelia, between the cells of which conjugation may take place. Union is accomplished between neighbouring cells of the same filament by means of short outgrowths, which meet and fuse as in the vil] USTILAGINALES 189 formation of clamp-connections (fig. 153a@), or between unrelated cells through a conjugation tube (fig. 1534). Where basidiospores are formed they conjugate in a similar manner. In every case the nucleus of one of the paired cells passes over into the other, and the two nuclei lie close together, though without fusion. The mycelium throughout the develop- ment of the host plant consists of binucleate cells and breaks up in spore- formation into binucleate segments (fig. 152@). Each young spore has thus two nuclei which fuse during development so that the mature brand- spore is uninucleate. In Ustilago Avenae, U. Hordet and U. Tritici, sub-species of U. Carbo, Lutman observed that on conjugation some of the cytoplasm of one of the cells passed over with the nucleus, the empty cell becoming shrivelled (fig. 154). In U. Avenae a long fusion tube is frequently formed and both Fig. 153. Ustilago Carbo: a. formation of basidium; Fig. 154. Ustélago Hordet; 6. conjugation; c. binucleate mycelium; after conjugation; after Lut- Rawitscher. man. nuclei, as well as the greater part of the cytoplasm, pass into it, leaving the conjugating cells comparatively empty. In these varieties of UV. Cardo Lutman found that, after conjugation, the two nuclei lie closely pressed together so that it was sometimes impossible to differentiate them. Ustilago Tragopogonis pratensis is parasitic on Tragopogon pratensis, in the flower heads of which it produces a mass of dark violet spores. In the young flower buds hyphae are abundant only in the anthers and ovary. Later they spread to the surface of these organs and form a dense mycelium of delicate filaments. According to Dangeard and to Rawitscher they divide, with the onset of spore-formation, into small binucleate cells; nuclear fusion takes place and the spore acquires a thick reticulate wall. In germination a three or four celled basidium is produced, each cell containing a single nucleus, and gives rise to uninucleate basidiospores, which increase by budding. 190 HEMIBASIDIOMYCETES [CH. Federley,in 1903,described specimens of this fungus in which conjugation is followed not only by the migration of the nucleus of one of the cells concerned, but also by nuclear fusion (fig. 155). In view of the fusion in the young spore recorded by Dangeard and by Rawitscher the details of de- velopment in this species de- mand further investigation. Ustilago Maydis, the smut of Zea Mays, induces_ con- Fig. 155. Ustilago Tragopogonis pratensis (Pers.) Wint.; siderable hypertrophy. The conjugation and nuclear fusion; after Federley. : deformations contain a mass of gelatinous mycelium from which brand-spores are produced. When mature, the spore mass causes the rupture of the enclosing tissues, and the spores escape. They germinate to produce basidia from which uninucleate basidiospores are abstricted. These in turn multiply by budding, but, accord- ing to Rawitscher, they never conjugate, nor do they form a definite mycelium (fig. 156@). In the infection of the host plant, hyphae are for the first time developed, and, unlike those of most investigated smuts, consist of uninu- cleate cells (fig. 1564). This is the case even when the hyphae begin to break up in preparation for spore-formation. At this stage, however, the ends of adjacent cells are seen to become swollen where they are in contact, the wall separating their protoplasm breaks down, the two nuclei come together in Fig. 156. Ustilago Maydis; a. basidiospores, x 540; 4. uninucleate mycelium, x 420; after Rawitscher. vir] USTILAGINALES 191 the swollen region and ultimately fuse (fig. 157). Thus the mature brand- spore in Ustz/ago Maydts, as in other species, contains a single fusion nucleus. Here, however, the nuclear association which usually takes place in the basidio- spore is postponed till just before spore-formation. The parasitic mycelium is therefore haploid instead of diploid as in the majority of cases. A very similar state of affairs has been described by I. Massee in Ustilago Vaillantzi which attacks various liliaceous plants, hibernating in the bulb and forming spores in the anthers and ovary. In these organs the hyphae produce numerous short branches divided by transverse septa into cuboid cells which, like the cells of the vegetative mycelium, contain each a single nucleus. Alternate septa disappear by deliquescence so that binucleate segments are formed in each of which the two nuclei approach one another and fuse to form the single nucleus of the spore. Germination in water takes place in the usual way; four-celled basidia are produced and give rise to basidiospores. Among these there is no evidence of conjugation. Ustilago antherarum forms its spores in the stamens of members of the Caryophyllaceae; pollen-formation is inhibited, and the anthers become filled with fungal spores, which are distributed by the mechanism prepared for the dispersal of the pollen. Germination takes place in dung decoction with great readiness, the tubes being put out in three or four hours. Harper has observed that when the spore nucleus undergoes mitosis one of the daughter nuclei remains in the spore while the other passes into the basidium (fig. 158@). Here it divides, the two resultant daughter nuclei are separated by a wall, the nucleus remote from the spore divides again and a second wall is formed. Thus the three-celled basidium characteristic of this species is constituted. Fig. 158. Ustilago antherarum Fig. 157. Ustilago Maydis; a. uninucleate cells Fr ; a. germination of brand- before spore-fi.rmation ; 4. conjugation; ¢. young, spore; 6. conjugation; after uninucleate brand-spores; after Rawitscher. Harper. 192 HEMIBASIDIOMYCETES [CH. Basidiospores are budded off in abundance from all three cells, and in turn give rise to conidia. In the meantime the basidium has separated from its parent brand-spore, and the spore, after nuclear division, may produce another basidium, and others in succession at the same spot, so that free basidia accumulate in the culture. If cultures in nutrient solution are allowed to starve, association now takes place between basidial cells, basidiospores or conidia by means of conjugating tubes (fig. 158). The paired cells increase markedly in volume, but no interchange of cytoplasm takes place and the nuclei remain in their respective cells without visible change. Harper observed that when fresh beerwort was supplied to his cultures at this stage the produc- tion of conidia began again. They are produced from one or both of the con- jugating cells, but only a single nucleus is concerned in the development of each conidium, the other remains quiescent and the conidia are uninucleate. In a host plant, the name of which is not recorded, Werth and Ludwig failed to find binucleate elements, the youngest cells in which they could iden- tify the nuclei being uninucleate (fig. 159 @). They infer that in this species nuclear association fails to take place, and no binucleate stage exists. This hypothesis accords well with Harper’s observations Fig. 159. Ustilago antherarum Fr.; a. young brand- on the saprophytic phase which spores: 6. older brand-spores ; c. basidia; d. basidio- he studied in material grown on spores ; after Werth and Ludwig Lychnis alba. On the other hand, a binucleate stage was identified by him in the sporogenous cells of U. az- therarum on Saponaria, and by Dangeard on Lychnis dioica. These facts suggest the possibility of two or more varieties of U. antherarum on different hosts and differing in their cytological behaviour; the forms studied by Dangeard and Harper point to a condition comparable to that of U. Maydis, while Werth and Ludwig’s observations indicate the possibility of a truly apogamous strain. A complete life-history of this fungus, in material obtained from a single host, would probably prove of interest. Another possibly apogamous form is Usée/ago levis, a common smut on oats. According to Lutman the _ basidio- spores give rise to considerable numbers of conidia. These are multinucleate if formed in crowded masses, uninucleate when comparatively isolated. Germinated conidia found on the epi- dermis of infected seedlings usually contain two or three nuclei. The parasitic hyphae are multi- Fig. 160. Ustilago ‘ev’s (K.and nucleate and their swollen ends, when spore- S.) Magn.; mycelium with : : - xi : mua'tiimeleate and binucleate f0rmation is about to take place, contain ten to cells; after Lutman fifteen nuclei. The final segments however are ot o> Gine. uninucleate or binucleate (fig. 160), but it is not known whether fusion takes place in them. The multinucleate character of the mycelial cells strongly suggests that no preliminary pairing of the nuclei occurs. In Ustilago Zeae Lutman also observed a mycelium of multinucleate cells; at the time of spore-formation binucleate and uninucleate cells and finally uninucleate spores appear. Tilletiaceae The principal genera of the Tilletiaceae are 72//etia, Entyloma, Tuburcinia, Urocystis and Doassansia. They have in common the continuous basidium with a terminal group of spores. Tilletia Triticti and 7. foetens are the stink brands of wheat, so called by reason of the strong odour of trimethylamin or herring brine given out by the brand-spores. The two species differ in the character of the epispore which is smooth in 7. foetens, reticulate in 7. 77iticz. In both cases spores are produced in the ovaries of the host, all tissues of which, except the outer coat, are destroyed. The spore masses are garnered with the crop, and damage all grains with which they are threshed or ground. The infected flour and contaminated chaff and straw are causes of disease in man and animals. On the germination of the brand-spore of 7. Z77ztecz the nucleus passes into the basidium and divides three times so that eight nuclei are formed. Eight basidiospores are budded off in a bunch at the apex of the basidium, and each receives a single nucleus. Frequently additional nuclear divisions take place and ten, twelve, or sixteen uninucleate spores may be produced. When the spores are fully formed short conjugating tubes grow out and connect neighbouring spores, often while these are still attached to the basidium (fig. 161). According to Rawitscher the nucleus of one cell of the pair passes over into the other and the nuclei lie near one another but without fusion. After con- : : Fig. 161. Zzlletia Tritict (Byerk) Wint.; Jugation the spores may become septate; a. basidium thirty hours after germination from those which contain two nuclei fila- _—f brand-spore; 4. conjugation of basidio- ; spores ; X 300; after Plowright. ments of binucleate cells grow out, and may give rise to conidia which are also binucleate. Under suitable conditions the binucleate hyphae bring about infection by pushing between the cells of the host seedling. In the cells of the sporogenous mycelium fusion of the G.-V. 13 194 HEMIBASIDIOMYCETES [cE pairs of associated nuclei takes place. Rawitscher observed a quite similar life-history in 7. aevts. In the parasitic mycelium of Doassansia Alismatis and Entyloma Glauci (fig. 162) Dangeard observed binucleate cells and the fusion of their nuclei VELA A ean ed aE i eS eb YX" Fig. 162. Development of brand-spores ; a. Doassansia Alésmatis (Nees) Corn.; 6. EZntyloma Glauctt Dang.; after Dangeard. in pairs in preparation for the formation of the brand-spores. The same stages were recorded by Lutman in Doassanszadeformans, Entyloma Nympheae and Urocystis Anemones (fig. 163). Fig. 163. Uvocystis Anemones (Pers.) Wint.; mycelium and young spore ball; after Lutman. Tuburcinia primufcola infects various species of Primula and gives rise to conidia as well as to brand-spores during its parasitic stage. Wilson has shown that the conidia develop in the young flower on a mycelium of uninucleate cells which apparently persists in the host plant throughout the winter. When the flower opens the conidia conjugate in pairs, and a nucleus passes through the connecting tube so that one conidium is empty and the other binucleate. Germ-tubes with paired nuclei are later produced and doubtless give rise to the mycelium of binucleate cells which bears the brand-spores. This mycelium ramifies in the superficial tissue of the placenta and between the ovules, giving rise to brand-spores in the same flowers in which the conidia were previously developed. On the germination of the vu} DS EReAGINAEES: 195 brand-spores, basidia and basidiospores appear, but no conjugation could be observed. 7. primulicola thus resembles the Uredinales in having two parasitic generations, the one with uninucleate, the other with binucleate cells. Its hibernating, uninucleate mycelium also recalls the parasitic mycelium of Ustilago Maydis, or of U. Vatllantit, which consists of uni- nucleate cells. USTILAGINALES: BIBLIOGRAPHY 1807 PREVosT, B. Mémoire sur la cause immédiate de la Carie. Fontanel, Montauban. 1847 BERKELEY, M. J. Propagation of Bunt. Trans. Hort. Soc. London, ii, p. 113. 1847 TULASNE, L. R. and C. Mémoire sur les Ustilaginées comparées aux Urédinées. mann. sci. Nat. 3 sér. vii, p. 12. 1853 DE BARY, A. Untersuchungen iber die Brandpilze und die durch sie verursachten Krankheiten der Pflanzen. Miller, Berlin. 1854 TULASNE, L. R. and C. Second Mémoire sur les Urédinées et Ustilaginées. Ann. sci. Nat. 4 sér..ii, p. 113. 1867 FISCHER von WALDHEIM, A. Sur la structure des spores des Ustilaginées. Bull. de la So¢. Imp. des Nat. de Moscou, xl, p. 242. 1883 BREFELD, O. Botanische Untersuchungen tiber Hefenpilze. V, die Brandpilze. Felix, Leipzig. 1887 ZU SOLMS LAUBACH, H. Ustilago TreubiZ Solms. Ann. du jard. bot. de Buitenzorg, vi, P- 79: 1888 WARD, H. MARSHALL. The Structure and Life History of Extyloma Ranunculé (Bonorden). Phil. Trans. clxxviii, p. 173. 1889 PLOWRIGHT, C. B. A Monograph of the British Uredineae and Ustilagineae. Kegan Paul, Trench & Co., London. 1894 DANGEARD, P. A. Recherches histologiques sur la famille des Ustilaginées. Le Botaniste, ili, p. 240. 1899 HARPER, R. A. Nuclear Phenomena in certain stages in the development of the Smuts. Trans. Wisconsin Acad. Sci. Arts and Letters, xii, p. 475. 1904 FEDERLEY, H. Die Copulation der Conidien bei Ustilago Tragopogi pratensis Pers. Ofversigt af Finska Vetensk. Soc. Férhandlingar, lxvi, No. 2, p. I. 1910 MCALPINE, D. The Smuts of Australia. J. Kemp, Melbourne. 1911 LUTMAN, B. S. Some Contributions to the Life-history and Cytology of the Smuts. Trans. Wisconsin Acad. Sci. Arts and Letters, xvi, pt. III, p. IQI1. 1912 RAWITSCHER, F. Beitrage zur Kenntniss der Ustilagineen. Zeitschr. f. Bot. iv, p. 673. 1912 WERTH, E. and LuDwIG, K. Zur Sporenbildung bei Rost und Brandpilzen. Ber. d. deutsch. Bot. Ges. xxx, p. 522. 1914 MASSEE, I. Observations on the Life-history of Ustzlago Vaillantiz, Tul. Journ. Econ. Biol. ix, p. 7. 1914 RAWITSCHER, F. Zur Sexualitat der Brandpilze 77//etia tritic¢. Ber. d. deutsch. Bot. Ges. xxxii, p. 310. 1915 WILSON, M. The Life-History and Cytology of Zuburcinta primulicola Rostrup. r Bee Report, Sect. K. 1915. CHAPTERS Ait PROTOBASIDIOMYCETES UREDINALES THE rust-fungi, members of the group Uredineae, Uredinales or Aecidio- mycetes, including over 1700 species, are without exception obligate parasites on the stems, on the sporophylls and especially on the leaves of vascular plants, usually on those of angiosperms or gymnosperms but in one or two cases of ferns. : The mycelium ramifies in the tissues of the host, sends haustoria into the cells, and may act as a local stimulant causing more or less marked hypertrophy and consequent curling or malformation of the infected part. Starch may be stored by the host, and this is so abundant in the hyper- trophies caused by the aecidial mycelium of Pzccinza Cariczs on the nettle, Urtica parvifolia, that they are eaten by the Himalayans; one or two other species are similarly employed. Where the mycelium penetrates into the perennial tissues of the host it is itself perennial. Spores and Sori. On the mycelium several kinds of spore are produced, minute spermatia in spermogonia, aecidiospores in aecidia, uredospores and teleutospores, sometimes mixed, sometimes separate, in more or less definite sori. One or more of these types of spore may be lacking, but the teleuto- spores are almost-invariably present, and it is on them that the classification of the group depends. Naturally enough it was some time before the various types of spore were recognized as belonging to the same fungus and the old generic names \N Fig. 164. Germinating teleutospores; a. Phragmidium bulbosum Schm.; 6. Triphragmidium Ulmariae Lk.; ¢. Coleosporium Sonchi Lev.; ad. Uromyces appendiculatus (Fabae) Lev.; after Tulasne. er CH. VUIT] UREDINALES 197 of the spore forms other than the teleutospore, such as Aecidium, Cacoma and Uredo, still survive in our nomenclature. The teleutospores (figs. 164, 165, 166) may be unicellular or they may be made up of two or more cells forming a compound structure, each cell of =e. SX 6 Fig 165. Cronartium asclepiadeum Fr.; te- leutospore mass with F 3 basi.ia and spores; af- Fig. 166. Melampsora betulina Desmaz.; germinating teleutospores ; ter Tulasne. after Tulasne. which germinates independently. The teleutospore is simple in Uromyces, Coleosporium, and Melampsora, it is two-celled in Gymmnosporangium and Puccinia, it is built up of three to ten superposed cells in Phragmidium, and of a larger number in Xenodochus. In Triphragmidium it consists of three cells laterally placed and in Chrysomyxa and Cronartium the simple teleuto- spores are so massed together as to simulate compound forms; their real nature is revealed by their early separation one from another. One-celled teleutospores occur exceptionally in the two-celled species and are known as mesospores. The teleutospores may be massed together and incrusted in the tissues of the host, or they may be detached readily from their stalks and carried by the wind or by other agencies. Further development may take place as soon as conditions are favourable, or may be delayed till after a resting period, usually till the spring following development. In either case the nucleus in each cell ultimately undergoes two successive divisions, which constitute a meiotic phase, and the daughter nuclei are separated by transverse walls, so that four uninucleate cells are produced. The teleutospore-cell thus functions as a tetrasporangium and divides into four portions, constituting the transversely septate basidium. From each cell a short, pointed branch or sterigma arises, its end dilates, a basidiospore 198 PROTOBASIDIOMYCETLES [CH. (sporidium) is formed and receives the nucleus and cytoplasm of the cell from which it arose. In Coleosporium, Ochropsora, and Chrysospora, nuclear division and septation take place within the teleutospore wall, and the basidiospores are budded out from it, so that the teleutospore cell becomes the basidium directly; in the majority of cases, however, the structure of the teleutospore is not such as readily to allow further growth, and development takes place after the extrusion of the contents’as a tubular outgrowth, the so-called promycelium, surrounded only by a delicate membrane (fig. 167). The nucleus migrates into this structure and here nuclear division takes place, transverse septa are formed and the basidiospores are produced. But it must be noted that the nucleus and cytoplasm of the young basidium are those of the teleutospore cell, whether development takes place within the original wall or by means of a promycelium. When the basidiospore germinates its germ-tube penetrates through the cuticle of the host and forms a mycelium of uninucleate cells bearing spermogonia and aecidia. The spermogonium is usually found on the adaxial side of the leaf; it consists of a group of more or less parallel, unbranched, upwardly directed hyphae, arising from a small-celled tangle below the epidermis or cuticle of the host. In the majority of cases the outer hyphae of each group elongate to form paraphyses, so that the spermogonium is restricted in extent, and acquires a flask-shaped or pyriform outline; the paraphyses push up through the ruptured epidermis of the host to project at a narrow ostiole (fig. 168 0). In I ie. 167. Sat beat gk clavariaeforme Fig. 168. a. Phragnidium violaceum Xees; germinating teleutospores; x 66 Wi : : bE 2% 1.2 g teleutospores; x 666. Wint., x 3303 6. Gymnosporangium clavariaeforme Rees, x 260; sper- mogonia; after Blackman. vill] UREDINALES 199 simpler forms, such as Phragmzdium, the spermogonium is indefinite in extent, and consists of spermatial hyphae arranged beneath the cuticle, which is perforated in the centre of the mass to form an ostiole. No regular para- physes are produced but a few spermatial hyphae may elongate and project as sterile threads (fig. 168 a). The spermatial hypha is a long, narrow cell with a central elongated nucleus. It is furnished at its free end witha ring of thickening which may be concerned with the disjunction of the spermatium. The development of the latter begins by the pushing out of a finger-like projection at the apex of the parent hypha. When it has attained its full size the nucleus of the hypha divides and one of the daughter nuclei enters the spermatium, which is cut off by a wall formed just above the thickened ring (fig. 169). The mature spermatium is a small more or less oval cell, enclosed in a very Hiss u6as) Gyre Boran ceupn craven d ata rre tim wall. The cytoplasm is finely Rees; development of spermatia, x 1185; after Blackman. granular with apparently no _ reserve material, and the nucleus is of relatively large size. When cultivated in solution of sugar or honey, spermatia have been induced to undergo a form of yeast-like budding, and this has been observed under natural conditions by Robinson in Puccenta Poarum. But, though many attempts have been made, it has so far proved impossible to bring about the formation of a mycelium. It seems, therefore, pretty clear that the spermatia are useless as agents of infection, and they differ also in structure from ordinary asexual spores. On the other hand the suggestion was long ago made that they may be male reproductive elements, and this is borne out by their large nuclei and lack of reserve material, and is by no means invalidated by the fact that they possess some slight power of germination. Recent investigation has shown that they are now no longer functional. As a rule considerable numbers of spermatia are to be found in various stages of degeneration scattered around the ostioles of the spermogonia. In some cases the spermatia are aggregated in sticky masses and appear to attract insects. The presence of sugars in the spermogonial contents has been demonstrated for species of Uromyces, Puccinia, Endophyllum, and Gymmnosporangium ; in some cases the spermogonia also possess a strong odour as in Puccinia suaveolens, or occur on bright spots which contrast with the green of the surrounding tissue. Such spots are usually yellow or orange, but are white in Uromyces Fabae and reddish-purple in Puccinia 200 PROTOBASIDIOMMCELES [CH. Phragmitis. A corresponding discoloration takes place around the young aecidia, and there is thus some suggestion that the spermatia, when functional, were carried to their destination by insects. The aecidia occur in groups, usually on the abaxial side of the leaf; in them the aecidiospores are produced in basipetal rows (fig. 170) alternating with small, abortive, intercalary cells, by the disintegration of which they are set free. They may be carried to consider- able distances by the wind, and there is evidence that they are sometimes distri- buted by means of insects or of snails. The mature aecidio- Fig. 170. Uvomyces Poae Raben.; aecidium just before SP ONS is usually subglobose __ the epidermis is broken through, x 310; after Black- or polygonal in form, it is Soe enclosed in a thick wall per- forated by several germ-pores, and contains red, yellow or orange pigment, and always two nuclei. In germination a hypha is put out which enters the host plant through one of the stomata and so penetrates into the _ inter- cellular spaces. The development of the aecidium begins by the mass- ing of hyphae either deep in Fig. 171. Uromyces Poae Raben.; young aecidium, the tissues of the host (Gym- x 370; after Blackman and Fraser. nosporangium clavartaeforme, Puccinia Poarum (Blackman and Fraser ’06), Puccenta Falcartae (Ditt- schlag ’10)), or directly below the epidermis (Phragmzdium violaceum (Black- man '04), Uromyces Poae (Blackman and Fraser ’06) (fig. 171), Puccinia Claytoniata (Fromme ’14)); these hyphae give rise to a more or less regular series of uninucleate cells. These are the fertile cells, but, before developing further, each, at any rate in the relatively primitive forms (caeomata), may cut off one or occasionally more terminal sterile cells which ultimately degenerate. The fertile cells may unite laterally in pairs (fig. 172), so that binucleate compound cells are formed; they may similarly pair with the ViIr] URE DINALES 201 cells below them (Fromme ’14), or each may receive a second nucleus by migration from a neighbouring vegetative cell (fig. 173). In each case they now constitute the basal cells of the rows of spores and they proceed at once to cut offaecidiospore mother- cells, each of which in turn divides to separate a small intercalary cell below from the aecidiospore above. Exceptionally binucle- ate cells may be observed Fig. 172. Phragmidium speciosum Fr.; a. fertile and sterile before the fertile layer is cells; 4. fusion of two fertile cells; after Christman. differentiated. In Puccinia Poarumnuclear migrations sometimes take place be- tween the vegetative cells at the base of the very young aecidium. These cells may grow up, either at once or after division, to form fertile cells. Theaecidiospores,then, ,,., g. 173. Phragmidium violaceum Wint.; migration of are the products of a sexual second nucleus into fertile cell of caeoma, x 950; after : Blackman. process by means of which two nuclei become associated within the limits of a single protoplasmic mass, form- ing the dikaryon or synkaryon of Maire. The nuclei thus brought together do not fuse, but undergo simultaneous division (fig. 174), so that a daughter nucleus from each passes into every new cell. Conjugate division is continued when the aecidiospore germinates.and a mycelium of binucleate cells is produced. The sporophyte of the rusts is thus normally inaugurated in the fertile cells of the aecidium. It is not unusual to find spores and vegetative cells which contain three or more nuclei; in these, as in the binucleate cells, and, indeed, in multinucleate cells of many different groups of plants, conjugate Fig. 174. MWelampsora Rostrupi Wagn. ; paired fertile cells, Blackman and Fraser. x 1200; after 202 PROTOBASIDIOMYCETES eer division takes place (fig. 175). The origin of the trinucleate cell by the fusion of three fertile cells has been observed, and no doubt it may arise by the migration of a second vegetative nucleus. Fig. 175. Puccinia Poarum Niels.; conjugate division, x 2280; after Blackman and Fraser. At the periphery of the aecidium the cells cut off from the basal cells divide in the usual way, so that two cells corresponding respectively to the aecidiospore and the intercalary cell are formed from each. The upper (aecidiospore) cells acquire very thick striated walls, lose their contents and form a sheath or pseudoperidium about the sporogenous part. The behaviour of the lower cells varies considerably ; Kurassanow has shown that in some cases they are quite small, like typical intercalary cells, while in others they are relatively well developed and form part of the pseudo- peridium. This is especially the case where the tissue to be broken through by the developing aecidium is dense or extensive. Centrally the pseudo- peridium arches over the contents of the aecidium. In this region it is derived from the cells first cut off by the central basal cells. These, like the others, divide transversely, and one of the daughter cells, usually the outer one, corresponding to the aecidiospore, becomes one of the elements of the pseudoperidium (Dittschlag, Kurassinow). When the aecidium reaches maturity the pseudoperidium pushes through the epidermis of the host and is then itself ruptured and exposes the ripe spores. It becomes torn and recurved so that the characteristic cluster-cup is produced (fig. 176). The pseudoperidium is sometimes much elongated and cylindrical or inflated, producing the forms known as roestelia (Gymnosporangium), and peri- dermium (Coleosporium, Cronartium and allied genera), so-called from their old generic names, or it may be represented only by a few paraphyses or altogether absent (Phragmidium, Melampsora). The latter forms, to which the term caeoma is applied, are probably primitive. In the majority of cases, after the fertile and sterile cells have been formed and nuclear association has taken place, the basal cells each give rise to a single chain of spores, but occasionally (Puccinza Falcariae (fig. 177), Endophyllum Sempervivi) they may branch and thus produce two or more spore-rows. In certain other species the basal cells regularly form a number of lateral buds or branches and each of these is cut off as a spore roe i fb VIII] UREDINALES 203 Fig. 176. Puccinia Gramints Pers.; a. infected leaf of Berberzs vulgaris, nat. size; 6. group of aecidia, x5. Uvomyces Poae Rabenh.; c. infected leaf of Ranunculus ficaria, nat. size; a. group of aecidia, x 20; E. J. Welsford del. mother-cell (fig. 178). The spore mother-cell divides in the usual way, separating the aecidiospore above from its sister-cell below, but the latter here forms an elongated stalk instead of an intercalary cell. Each outgrowth of the basal cell thus produces only a single spore, the mode of formation of which is exactly similar to that of a uredospore. The fructification has generally been regarded as a uredosorus and is known as the primary uredosorus, in reference to its appearance relatively early in the season. Fig.177. Puccinia Falcariae; branched Fig. 178. Phragmidium Potentillae-Canadensis fertile cell of aecidium or primary Diet.; a@. conjugation; Jd. branched fertile uredosorus, x 1200; after Dittschlag. cell; after Christman. 204 PROTOBASIDIOMYCETES [CH. But the fact that these sori are developed on the same mycelium as the spermogonia, the fact that in their fertile cells nuclear association takes place and the fact that in the formation of the fertile cell a sterile cell is cut off, all suggest that the true homology is with the aecidium. The mycelium formed by the germination of the aecidiospore grows with renewed energy. It consists of binucleate cells giving rise to uredospores. These are borne in groups or uredosori (fig. 179) which may be surrounded Fig. 179. a. Phragmidium Rubi Pers.; uredosorus, x 600; after Sappin-Trouffy; 6. Phragmedium violaceum WWint.; uredosorus, x 480; after Blackman. by paraphyses, or in certain genera (Puccinzastrum, Uredinopsis) by a pseudo- peridium, In the young sorus a regular layer of somewhat rectangular basal cells is formed, from which the uredospore mother-cells arise. In Coleo- sportum, in Chrysomyxa, and in the secondary caeomata of Phragmidium subcorticium, they are produced in vertical rows like the typical aecidiospore mother-cells and divide to form uredospores and intercalary cells, but, in the large majority of cases, they appear as a succession of buds from different parts of the basal cell. Each bud elongates, its nuclei undergo conjugate division, a stalk is cut off which grows in length but remains narrow, while the uredospore enlarges considerably, its contents acquire an orange or yellow. colour, and its wall is variously roughened in most species by minute projections on the surface. Two or more germ-pores are usually present and the uredospore, like the cells which give rise to it, is invariably binucleate ; it produces a binucleate mycelium on which teleutospores or further crops of uredospores are formed. Certain species (Pzccinia vexans,etc.),occurring under very dry conditions, vill] UREDINALES 205 produce a second type of uredospore with thick walls which are adapted to survive unfavourable conditions; these are known as amphispores. Both aecidio- and uredospores germinate readily and without a rest if fully ripe, but many are shaken off by wind and rain before they reach maturity and remain incapable of germination. Moreover it is stated that spores will not ripen properly on leaves that have been removed from the plant. Sooner or later the mycelium of binucleate cells gives rise to teleuto- spores; these are characteristically grouped together in teleutosori (fig. 180), Fig. 180. a. Phragmidium Rubi Pers.; teleutosorus, x 240; after Sappin-Trouffy; 6. Phragmidium violaceum Wint.; teleutosorus, x 240; after Blackman. except in the genus Uvedinopsis, on ferns, where they are scattered. Like the uredospores the teleutospores are with or without paraphyses and like them arise from rectangular basal cells. They appear as narrow binucleate outgrowths in which one or more divisions take place so that, in the majority of cases, a stalk is formed below and the simple or compound teleutospore is produced above (fig. 181). The stalk may increase consider- ably in length (Gymmnosporangium, Uromyces, Puccinia) or may be very short or absent (Co/cosporium, Melampsora). As already stated the young teleutospore cell is binucleate (fig. 182); when the wall is fully thickened the two nuclei fuse and the spore passes into the resting state. On the renewal of its development two nuclear divisions occur and the gametophytic phase is initiated with the production of the uninucleate basidiospore. In the Uredinales the fertilization process thus takes place in two stages, nuclear association being separated by a longer or shorter series of vegetative cells from nuclear fusion. We have here a difference in degree though not 206 PROTOBASIDIOMY CETES [crs in kind from the normal process. In Pzzus sylvestris! the male and female nuclei lie side by side but do not fuse till their chromosomes become mingled on the first spindle of the embryo; in many of the protozoa and in some other animals a series of conjugate divisions may precede the combination of the paternal and maternal chromosomes in a single membrane. Fig. 181. Puccinia Podophylli S.; Fig. 182. Phragmidium violaceum Went.; a. teleuto- fertile cell of teleutosorus giving spores, x 1080; 4. fusion of nuclei in teleutospore, rise to teleutospores; after Christ- x 1520; after Blackman. man. It may be hazarded that in the Uredinales the similarity of the physio- logical history of the nuclei before they become associated is responsible for a minimum of attraction between them, so that there is no sufficiently strong impulse towards fusion till meiosis is about to take place; being, however, in the same cell, they have no opportunity of dissolving partnership and the influences which bring about meiosis affect both alike. A considerable similarity exists in the arrangement of the different groups of sporogenous cells. The uredo- and teleutosori are clearly com- parable, both are of indefinite extent, with or without a border of paraphyses, and both consist of groups of rectangular basal cells from which the spore mother-cells arise in horizontal series and divide to produce the simple or compound spore and the stalk-cell. Sometimes, however, the uredospores are borne in vertical series, one below the other, and the sister-cells of the spore form short, intercalary cells instead of stall cells (fig. 183). This arrangement and that of the so-called primary uredospores link the uredosorus to the aecidium, suggesting the homology of the stalk and inter- calary cells. In the simplest aecidia, those of the caeoma type, we have a ‘ Blackman, V. H., 1898, Phd. Trans. B. cxc, p- 395 vill] UREDINALES 207 group of basal cells of indefinite extent, from which the aecidiospore mother- cells are cut off. The aecidium is, in fact, no more a definite organ than the uredo- or teleutosorus, and only appears so in the more elaborate forms because of the modification of its peripheral cells to form a pseudoperidium. The important distinction lies not in the general morpho- logy of the sorus, but in the fact that an association of two nuclei from different cells takes place in the basal cell of the aecidium and in the specialization indicated by the separation of the sterile cells. In its general structure the spermogonium, con- sisting as it does of a series of spermatial hyphae with or without circumjacent paraphyses, is not very different from the other sori, and, in the simplest cases, it also is of indefinite extent. Figedey§ Coveosdoreu ye soe Omission of Spore Forms. In many rusts one chi; uredosorus, x 545 ; after Holden and Harper. or more spore forms are omitted; the case where the so-called primary uredospore is substituted for the typical aecidiospore has been already described; these and others in which the characteristic aecidium or caeoma alone is lacking are distinguished by the prefix brachy. Hemi- indicates the presence of uredo- and teleutospores without aecidia or spermogonia. The suffix opsis is used for forms with aecidia and teleutosori. They lack uredosori but a few uredospores are sometimes found in the teleutosorus. Micro- and lepto- forms have teleutospores with a few occasional uredospores and sometimes spermogonia. The teleutospores germinate in the former group only after a period of rest, in the latter upon the same host plant as soon as they reach maturity. Species with the full complement of spores are distinguished by the prefix eu. As already pointed out, the sporophyte in some of the drachy- species starts from the fertile cells at the base of the so-called uredosorus, and this may very probably prove to be true in all cases where the ordinary aecidium is absent and spores developed like uredospores accompany the spermogonia. The alternation of generations in the -ofszs forms is also normal, for these are characterized by the omission of typical uredosori the development of which is related to no significant change in the nuclear life-history. In mzcro- and /epto- forms the basidiospore germinates to produce, as in eu- species, a mycelium of uninucleate cells on which spermogonia may occasionally be borne. The mycelium becomes binucleate either during vegetative development (Uromyces Scillarum, Puccinia Adoxae) or below the young teleutosorus, and the fusion in the teleutospore takes place in 208 PROTOBASI DIOMY CE TES [CH. the usual way. In the mdcro- form Puccinia transformans Olive observed that the binucleate condition was brought about by the fusion in pairs of cells to form the basal cells from which the teleutospores arose and the same has been reported by Moreau for Puccinia Buxi and Uromyces Ficariae. In Puccinta Malvacearum Moreau occasionally found a difference in size between the fusing cells, and Werth and Ludwig observed the migration of the nucleus of the smaller cell into the larger (fig. 184 a). Below the teleutosorus of Puccinia Podophylli also, Christman found nuclear migrations in progress (fig. 184). Such cases clearly suggest that here, as in the mycelium below the aecidium of P. Poarum and in the prothallus of pseudapogamous ferns, the sporophyte is initiated by the association of two vegetative nuclei. Christman, however, observed that in certain cases migration took place between cells already binucleate, and he hence regards migrations in this case, and is inclined to regard all other migrations in rusts, as due to pathological causes. Fig. 184. Puccinia Malvacearum Mont.; a. conjugation Fig. 185. LZndophyllum Sempervivi of unequal cells at base of teleutosorus; 4. teleutospore ; Lev.; fertile cells and spores; after both after Werth and Ludwig. c. Pucctnta Podophylli Hoffmann. S.; migrations at base of teleutosorus; after Christinan. A sporophytic stage of exceptionally brief duration is also found in the species of Exdophyllum and in the form on Rubus frondosus known as Kunkelia nitens'. In both cases the characteristic spores are developed in basipetal chains (fig. 185), and in both the fertile cells which give rise to them fuse in pairs (Olive ’08; Hoffmann ’11), so that the spore mother-cells, intercalary cells and spores receive two nuclei each. In Exdophyllum the spores are enclosed in a pseudoperidium of barren cells so that the sorus appears as a typical aecidium, in Azshel/ia nitens it is of simpler, indefinite ! Kunkelia nitens (Schwein.) Arthur = Caeoma nitens Burr. VIII] UREDINALES 209 form; in both cases it is borne in association with spermogonia on a mycelium of uninucleate cells. But the spore germinates like a teleutospore Fig. 186. Endophyllum Sempervivi Lev.; spores giving rise to basidia; both after Hoffmann. (fig. 186); its two nuclei fuse (fig. 187), its contents are extruded as a pro- mycelium, two successive nuclear divisions occur, cross walls appear and four basidiospores are produced, which, in due course, give rise to a uninucleate mycelium. The sporophytic stage thus endures only from the fusion of the fertile cells until the germination of the spores which they produce. Incidentally these observations in the case of Kunkelia nitens have demonstrated that the caeoma of this fungus is not a stage in the life-history of the teleutospore-producing Puccéntza Peckiana on the same host, for the mycelial cells of P. Peckiana are binucleate and the teleutospores germinate in the usual way. Thedevelopment of an apo- gamous aecidium has been ob- served by Moreau in a variety of Endophyllum Euphorbiae on yy of % ) neh 97.8: Sy wa = s Euphorbia sylvatica; here the FRY BI S44 "a basal cells, aecidiospores and Be farcaie ai | xs Fi . . Nass cells of the pseudoperidium are uninucleate throughout their development, the aecidiospore germinates to form a promy- celium of three or four cells Fig: 187: Endophyllum Sempervivi Lev.; @. nuclear : fusion in spore; 4. synapsis in fusion nucleus; after and neither nuclear association Hoffmann. or Seles: , \w O4)3*, a G.-v, 14 210 PROTOBASIDIOMYCETES [cH. nor nuclear fusion takes place at any stage, the diplophase being wholly omitted. Heteroecism. In many rusts the gametophytic and sporophytic mycelia occur on different host plants. Such forms are termed heteroecious in contrast to the autoecious species where the whole life-history is passed on a single host. It is not surprising that the different spore forms on such species were recognized and described some time before it was understood that they are stages in the life-history of a single fungus. The final proof of the relationship of the aecidia and spermogonia on the one hand and the uredo- and teleutosori on the other, was given by de Bary in 1865 for Puccinia Graminis, the wheat rust or, as the teleutospore stage was called by early investigators, the wheat mildew. In this plant the haplophase occurs on the leaves of the Barberry (Berberis vulgaris) and the diplophase on wheat, oats, rye and other grasses. Long, however, before this relationship was demonstrated, and even before the fungal nature of the disease was known, farmers had begun to suspect some malign connection between barberry bushes and their wheat crop, and had observed that dark areas of blackened and injured wheat were apt to occur in the neighbourhood of such plants. In the State of Massachusetts an act was passed requiring the inhabitants to extirpate all barberry bushes before a given date in 1760 and Marshall, of Norfolk, writing in 1781, says that “it has long been considered as one of the first of vulgar errors among husbandmen that the barberry plant has a pernicious quality (or rather a mysterious power) of blighting wheat which grows near it.” It is hardly to be wondered at that learned persons of the time repudiated this belief, or, as Marshall says of himself, “very fashionably laughed at it.” It was not till 1797 that Persoon identified the wheat disease as a fungus and gave it the name it still bears. In 1805 Sir Joseph Banks called attention to its resemblance to the rust on the barberry, suggesting that it might be one and the same species, “and the seed transferred from the barberry to the corn.” In 1816 Schoeler, a Danish schoolmaster, set himself to deal with the matter experimentally, and applied rusted barberry leaves to some marked plants of rye; after a few days these were badly affected while not one rusty plant could be found elsewhere in the field. His discovery was con- firmed by the investigations of de Bary, who performed the infection in both directions and under more critical conditions, and it has since been shown that a large proportion of the rusts are in fact heteroecious. It seems pretty evident that the autoecious condition must have been primitive and it would be of interest to know what factors determined the adoption of different hosts for the different phases of the life-history. 1 Rural Economy of Norfolk, 2nd ed. vol. ii, p. 19, London, 1795. t —. vill] UREDINALES 2 Christman and Olive have inferred that the ancestral type of the heteroecious species was a form with teleutospores only, a /efto- or a micro- form occurring on the host of the present gametophyte. Other investigators (Tranzschel 04, Grove ’13) who regard the aecidium as an essential constituent of the primitive rust, have suggested that heteroecism may have arisen in relation to host plants with a short vegetative period. In such a case there would hardly be time for the production of the full complement of spores and the fungus might either shorten its elaborate life-history, giving the mzcro- or simi- lar forms (Uromyces Scillarum on wild hyacinth, Puccinia fusca on anemone), or some of the spores might become adapted to life on a new host. This might be the case in particular with the aecidiospores, the development of which, owing perhaps to the recent fertilization stage, is especially vigorous. ‘Aecidiospores must fall on hundreds of leaves besides those of the host, and the germ-tubes in their case enter through the stomata. If then an aecidiospore germinated and penetrated a satisfactory host it is suggested that a mycelium might develop and further adaptations might fix the heteroecious habit. Again it is readily understandable that the Gramineae and other hosts with similarly refractory cuticles are easily infected by the germ tubes from the aecidio- and uredospores which pass through the stomata but not by those of the basidiospores which, in a large majority of cases, penetrate the walls of the epidermal cells. This fact may be significant in relation to the return of the parasite to its gametophytic host each spring. There is reason to believe that some species have an autoecious and a heteroecious variety and the study of such forms is likely to prove of great assistance. Specialization of Parasitism. The parasitism of the rusts shows very marked specialization so that biological species have arisen, which, though they may be morphologically indistinguishable, differ from one another in their power to infect different hosts. Injury to the host may break down its resistance to attack and may render it liable to infection by a species to which it is normally immune. Under favourable conditions rust appears suddenly, and spreads with great rapidity. Eriksson believed such epidemics to depend on the presence in the seeds or buds of the host plant of the protoplasm of the rust, indistinguishably mingled with that of the host, a mixture to which the term mycoplasm was applied. He considered that the protoplasm of the fungus remained unaltered till the leaves were formed; under appropriate conditions it then separated itself rapidly from that of the host and developed into the ordinary spore-bearing mycelium. The investigations of Marshall Ward and others have not substantiated this hypothesis. Nuclear Division. It would appear, from the work of various observers, that nuclear division in the Uredinales has undergone a process of simpli- 14—2 212 PROTOBASIDIOMYCETES [CH. fication and in some cases it shows but few of the characters of normal mitosis. In the spermatial hyphae of Gymnosporangium clavariaeforme, for example, Blackman has described a condensation of the nucleus to form a deeply staining body out of which the nucleolus is squeezed. The chromatin is drawn apart into two apparently homogeneous masses between which a kinoplasmic thread represents the spindle. A similar process takes place in the division of the conjugate nuclei in this and other forms, but the spindle is generally recognizable somewhat earlier, at a time when the chromatin of each nucleus still forms a single mass. As a rule the spindles of the conjugate nuclei lie parallel one to another (fig. 188). Moreau, following Sappin-Trouffy, has recorded two chromosomes or chromatin masses formed from each nucleus in various Uredi- fer . KOE neae. Olive on the other hand tal of s e . . . = in Lriphragmidium Ulmartae and Uromyces Scirpz has found Fig. 188. Uromyces Poae Rabon conjugate divisions = clearly defined spindle and in aecidium, x 1330; after Blackman and Fraser. centrosomes and has succeeded in recognizing several separate chromosomes; a similar state of affairs has been recorded by Christman for Phragmidium speciosum so that it would ap- pear that the different species of rusts are at dissimilar levels in this matter, though a further study of carefully fixed material might be undertaken with ad- vantage. In all cases, however, the divisions of the fusion nucleus of the teleutospore are much more elaborate than those in the Fig. 189. Coleosporium Senectonis; mitosis in teleuto- vegetative cells and show some spores; after Arnaud. Ag 25 (ata of the characteristics of a meiotic phase. In Coleosporium (fig. 189) the fusion nucleus at first possesses a well-marked reticulum of interlacing threads. This undergoes a stage of concentration in one part of the nuclear area, which no doubt corresponds to synapsis, and afterwards loosens out, increases in thickness and forms a spireme. The spireme breaks up and its segments are seen to be double throughout their length. In the meantime centrosomes and spindle fibres have appeared and characteristic gemini are recognizable on the spindle. -extra-nuclear and it lies free in vit] UREDINALES 213 Moreau describes only two, but Harper and Holden found a larger number, which became crowded together and more or less fused during the later stages of the first and also during the second division. In Gymnosporangium clavartaeforme (fig. 190) the first division is initiated, as in Coleosportum, by a synaptic phase, after which a spireme is formed and breaks up into chromosomes. These pass on to the spindle but soon lose their individuality and travel in irregular masses to the poles. The development of the spindle has also been traced in this species; its formation is the cytoplasm before coming into relation with the dividing nucleus. This type is fairly common among animals but is of exceptional occurrence in plants. Nuclear Association. The cytology of the aecidium was first described in detail in 1904 e by Blackman, for Phragmidium Fig. 190. _ Gymnosporangium clavariaeforme Rese. : : 7 first division in basidium, x 1460; after Blackman. violaceum, a species occurring on the bramble. The aecidium here is of the caeoma type, consisting of a group of fertile cells of indefinite extent and usually bounded at the periphery by a number of thin-walled paraphyses. Its formation begins by the massing of hyphae below the epidermis of the leaf where they form a series of uninucleate cells two or three layers thick. The cells next the epidermis increase in size and each divides by a transverse wall parallel to the surface of the leaf, separating an upper sterile cell from the fertile cell below. The sterile cells remain cubical and ultimately disintegrate; the fertile cells elongate to form a more or less regular layer and paired nuclei appear in them, fmt at the centre and later towards the periphery of the group (fig. 191). if = P ( ee ) ' Fig. 191. Phragmidium violaceum Went.; caeoma, The second nucleus in the x 240; after Blackman. 214 PROTOBASIDIOMYCETES [Ce fertile cells of Phragmidium violaceum was shown by Blackman and subse- quently by Welsford to be derived from one of the smaller cells at the base of the fertile layer. It is thus a vegetative nucleus; it enters the fertile cell by migrating through the wall, becoming much drawn out and laterally com- pressed. It leaves a pore which may be identified after its passage (fig. 192). Fig. 192. Phragmidium violaceum Went.; caeoma; a. migration of nucleus from vegetative cell of one hypha to fertile cell of another, x rogo; 6. and c. Linucleate cells showing the pore through which the second nucleus has passed, x toro; after Welsford. After entering the fertile cell the second nucleus is at first smaller and Fig. 193. Uromyces Poae Kaben.; nuclear migra- tionsin youngaecidium x g50; after Blackman and Fraser. denser than that originally present, but soon becomes similar to it in size and consistency. The fertile cell now elongates and in doing so pushes through and destroys the sterile cell above. The associated nuclei divide simultaneously, a transverse wall is formed between the pairs of daughter nuclei cutting off the aecidiospore mother-cell, and the process is several times repeated so that a row of cells is formed. Each of these divides again to separate a small, binucleate intercalary cell below from the binucleate aecidiospore above. A similar type of development initiated by the migration of a vegetative nucleus into the fertile cell, was observed by Blackman and Fraser in the aecidia of Puccinza Poarum and Uromyces Poae (fig. 193). But in neither of these was the sterile cell satisfactorily identified. In such cases it seems reasonably clear that the entrance of the second nucleus is not a primitive process but a form of reduced fertilization where a VIII] UREDINALES 215 vegetative nucleus has replaced that of the no longer functional male element. As already shown there is a strong presumption that this male element was the spermatium and the fertile cell may then be regarded as an oogonium and the young aecidium as a group or sorus of female reproductive organs. In this connection Blackman has suggested a possible origin of the sterile cell; in Phragmidium violaceum he found it to be occasionally elongated and pushed up between the cells of the epidermis so that it was covered only by the cuticle (fig. 194); if in the past it broke through this also, it would have formed an efficient trichogyne and may well have func- tioned as such. In the related species Phragmidium speciosum, Christman, in 1905, described a similar development of sterile and reproductive cells, but in this case the fertile cells become inclined one towards another in pairs and, at the point of contact, the walls dissolve so that the protoplasts come into relation, at first through a small pore, but later along the greater part of their length. Binucleate cells are thus formed (fig. 195), conjugate division Fig. 194. Phragmtdium violaceum Went. ; Fig.195. Phragmidium speciosum Fr. ; caeoma; sterile cell pushing up between fertile cells after conjugation ; aecidio- epidermal cells of host, x 1300; after spore mother-cell above; after Christ- Blackman. man. takes place and aecidiospore mother-cells are cut off so that a single row of aecidiospores is developed from each pair of gametes. Christman regards the fertile cells as isogametes between which conjugation takes place, and the sterile cells merely as buffers, of which the function is to assist in the rupture of the epidermis. His observations on Phragmidium spectosum were confirmed in 1906 by Blackman and Fraser for Welampsora Rostrupi on Mercurialis (fig. 174); these authors pointed out that the fusion of the fertile cells is a reduced fertilization, strictly comparable to that in P%. vzolaceum but achieved by the union of female cells in pairs instead of by the entrance of a vegetative nucleus into the female cell. This interpretation is confirmed by the fact 216 PROTOBASIDIOMYCETES [cay that Moreau found both processes (cell-fusion being considerably more common than migration) in the same caeoma in Phragmidium subcorticium. Since 1905 nuclear association by the fusion of fertile cells in pairs has been observed in a number of species, and seems, according to our present knowledge, to be the usual method. In the primary uredosorus of 777phragmidium Ulmartae and in certain other species, Olive, in 1908, found arrangements of an intermediate type. Here the cells of the young fructification form a more or less regular layer and cut off sterile cells in the usual way. Other hyphae then push up among them, and cell fusion and nuclear association take place (fig. 196). Fusion begins through a narrow pore which afterwards broadens, and in many cases the nucleus of the younger cell migrates into the older one. The process is thus intermediate between Fig. 196. Zriphragmidium Ulmariae those first observed by Blackman and (Schum.) Link; primary uredosorus; Christman respectively, and the younger condition intermediate between migra- : i tion and conjugation of fertile cell; hypha, which does not cut off a sterile cell, after Olive. may be regarded as either a vegetative structure or a gametangium. Olive suggests that the migrations, recorded by Blackman and by Blackman and Fraser, may be merely early stages of a completer cell-fusion; the recent critical work of Welsford, however, nega- tives this hypothesis, nor would the occurrence of cell-fusion be of much importance once nuclear association had taken place. Phylogeny. The interpretation given to the processes which take place in the aecidium affects the conception of other spore-forms in the Uredinales and indeed of the phylogeny of the group. For Christman, the sporophyte arises by the conjugation of undifferen- tiated or scarcely differentiated isogametes which fuse to form the basal cells of the aecidium. The spermatia cannot on this interpretation be male organs, and he regards them as the once-functional asexual spores of the gametophyte. The basal cells of the aecidium are homologized with those of the uredo- and teleutosori, and the fact is emphasized that the basal cells of the primary uredosorus and sometimes of the teleutosorus also may arise by cell-fusions similar to those in the aecidium. Christman is inclined therefore to regard the mcro- species, in which the only spore-forms are teleutospores, or teleutospores and spermatia, as the primitive rusts, and to see in them a gametophytic mycelium bearing asexual spores (spermatia) and undifferentiated gametes by the union of which the basal cells of the teleutosorus are produced. Outgrowths of these cells bear the teleutospores a Lea) VIIT] UREDINALES 217 in the germination of which the sporophyte comes to an end and the new gametophyte is initiated. Into this simple life-history the uredospore and aecidiospore are held to be afterwards successively inserted as extensions of the sporophytic phase. From such a point of view the rust might be related directly to the Phycomycetes or other simple forms. Blackman’s work, on the other hand, indicates that the spermatium is an abortive male element, the fertile cells of the aecidium are female organs which, in the absence of normal fertilization, either fuse in pairs or receive a vegetative nucleus by migration. In wzcro- forms the female organs have disappeared and the abbreviated life-cycle, like that of the pseudapogamous ferns, shows the sporophyte initiated by an association of two vegetative nuclei. The ez- forms (or the -ofszs forms with teleutospores, aecidiospores and spermatia), are therefore primitive and the forms with a shorter life- history are of secondary origin and reduced. The female organ consists of two cells, the upper of which may have functioned as a trichogyne. Comparing the two hypotheses it may be noted that Blackman’s has the advantage of correlating all the known facts, since the association of female nuclei in pairs and of female and vegetative nuclei are both observed methods of replacing normal fertilization. Christman, on the other hand, is obliged to ignore the migrations of vegetative nuclei, or to regard them as pathological. Even for this reason alone it would appear, in the present state of our knowledge, more probable that the Uredinales are a group in which the normal sexual process has disappeared, and is replaced by various forms of pseudapogamy. The young aecidia must then be regarded as groups of female organs, each consisting of a fertile and a sterile cell, and the sper- mogonia would appear to be corresponding groups of male organs, the spermatia or antheridia, with the filaments which bear them. A third suggestion proposes Exdophyllum as a primitive form. The mycelium of uninucleate cells bears spermatia and cluster-cups. At the base of the cup fusion of fertile cells in pairs occurs, and spores and inter- calary cells are produced in chains. The spore germinates by the formation of a septate basidium on which four basidiospores are produced in £. Euphorbiae, but an irregular number, sometimes as many as eight from one cell, in Z. Sempervivi. In Uromyces Cunninghamianus (on Jasminum) Barclay, in 1891, observed that the aecidiospore germinates by a tube in which one transverse wall is formed and the cells give rise to secondary hyphae which produce infection. On the resultant mycelium, spores similar in arrangement to aecidiospores are formed; so that here, as in Coleosporium, we have the accessory spores of the diplophase produced in chains. In the same sorus teleutospores, which are in this genus unicellular, may also arise. The cytology of this 218 PROTOBASIDIOMYCETES [CH. species has not been investigated, but there is an indication of a transition between Endophyllum and the eu- forms It is postulated that the cells of the promycelium of an Endophyllum-like ancestor might have produced infection directly instead of by means of basidiospores. Nuclear fusion and meiosis would be postponed till the formation of teleutospores, which would arise as the typical spores of this new vegetative sporophyte. Later the teleutospore would become specialized as a resting spore and uredospores would take on the function of rapid propagation of the plant. But Exdophyllum has a definite cluster-cup, and well-marked peridium, and is therefore not likely to be primitive, though it may point to an hypothetical primitive ancestor; a species must rather be sought with a caeoma from the aecidiospores of which promycelia are produced. Such a form has been recognized in Kunkelia nitens. There remain to be considered the various forms of teleutospore. Presumably the unicellular type is more primitive than the multicellular. Simple teleutospores occur in /elampsora (where also the aecidiospores are developed in a caeoma), in Uvomyces and in the Coleosporiaceae. In the last-named family meiosis and septation take place inside the teleuto- spore wall, but the elaboration of the other spore-forms forbids this group being regarded as primitive, though the internal basidium may be. It may be hazarded that the ancestral rust bore spermogonia or groups of male organs and groups of female organs of the caeoma type, that the individual male organ was an antheridium or spermatium set free from its parent hypha, that the female organ consisted of a fertile cell or oogonium and a sterile cell which was perhaps elongated to form a trichogyne reaching up to the surface of the host, and that the product of fertilization was a series of aecidiospores. It may further be suggested that either the aecidiospore germinated by giving rise at once to a promycelium or that an alternation of vegetative generations occurred and that the sporophyte bore simple teleutospores or tetrasporangia inside which septation took place. The members of the Uredinales may be arranged in four families: Germination by a promycelium (except in Chrysopsora) Teleutospores stalked PUCCINIACEAE. Teleutospores sessile arranged in series but separating later CRONARTIACEAE, one or many celled, loose in tissue of host or united in a flat layer under the epidermis MELAMPSORACEAE. Germination without a promycelium, formation of basi- dium internal; teleutospores sessile or with a lateral pedicel COLEOSPORIACEAE. “ vul] UREDINALES 219 Puccintaceae’. The teleutospores of the Pucciniaceae are provided with a stalk which is often well developed, but is in some cases short or becomes detached at an early stage (deciduous). The teleutospores are one-celled in Uromyces and Hemitleta, two-celled in Puccinia and Gymnosporangium; they are made up of three cells in 777phragmidium, and in Phragmidium of three or more cells. Gymnosporangium is further characterized by the long pedicels of the teleutospores and the fact that they are imbedded in a gelatinous mass. The uredospores are solitary and the aecidiospores produced either in caeomata (77phragmidium, Phragmidium), or in aecidia, which in Gymno- sporangium are commonly elongated to form flask-shaped or cylindrical roestelia. This family probably includes some of the most highly developed members of the Uredinales, but it includes also several species with caeo- mata, and one, Chrysopsora Gynoxidis, belonging to a monotypic genus in Ecuador, in which the two cells of the stalked teleutospore germinate by internal septation and the protrusion of sterigmata bearing basidiospores as in Coleosporium. Cronartiaceae In the Cronartiaceae the teleutospores are unicellular and sessile, so that they simulate multicellular spores. In Chrysomyxa they form waxy crusts, and in Cronartzum a cylindrical body. A pseudoperidium is developed around the aecidiospores. The genus Exdophyllum is sometimes placed here, sometimes a separate family, the Endophyllaceae, is constituted for it; it differs from the rest of the Cronartiaceae and from the majority of the rusts in the fact that its basidia are developed from spores resembling aecidiospores which arise in an aecidium-like sorus protected by a pseudoperidium. Melampsoraceae The teleutospores are sessile, loose in the tissue of the host in Uved- nopsts, in the other members of the family grouped in a flat layer under the epidermis. In JZelampsora and its immediate allies they are unicellular ; in other genera they are divided either vertically into two cells or by cruciately arranged septa into four. The aecidiospores may be surrounded by a pseudoperidium or arranged in a caeoma; sometimes a pseudoperidium is present around the uredosorus also. 1 For Bibliography of this and other families, see the end of the group. 220 PROTOBASIDIOMYCETES [CH. Coleosporiaceae The outstanding character of the Coleosporiaceae is the method of germination of the unicellular teleutospore which undergoes septation directly and, in Coleosporium and Ochropsora, without the protrusion of a pro- mycelium; in Zaghouania the contents of the teleutospore divide within the teleutospore-wall to form four cells, but emerge before the basidiospores appear. The aecidia are cup-shaped in Ochropsora, but in Coleosporium and Zaghouania they are of the peridermium type with a cylindrical, more or less inflated peridium; this elaborate type of aecidial sorus makes it impossible to regard the family as primitive though it may perhaps have branched off early from the line leading to the commoner type of rust. UREDINALES: BIBLIOGRAPHY 1889 PLOWRIGHT, C. B. A Monograph of the British Uredineae and Ustilagineae. Kegan Paul, Trench & Co., London. 1891 BaRcLAy, A. On the Life history of a remarkable Uredine on Jasminum grandi- florum. Trans. Linn. Soc. Bot. ii, p. 141. 1895 POIRAULT, G. and RACIBORSKI, M. Sur les noyaux des Urédinées. Journ. de Bot. ix, pp- 318 and 381. 1896 SAPPIN-TROUFFY, P. Recherches histologiques sur la famille des Urédinées. Le Botaniste, v, p. 59. 1902 DUMEE, P. and MAIRE, R. Remarques sur le Zaghouania Phyllyreae, Pat. Bull. Soc. Myc. France, xviii, p. 17. 1903 HOLDEN, R. J, and HARPER, R. A. Nuclear Divisions and Nuclear Fusion in Coleosporium Sonchi-arvensts, Lévy. Trans. Wisconsin Acad. Sci., Arts and Letters, XIV, pt. 1, p: 63: 1904 BLACKMAN, V. H. On the Fertilization, Alternation of Generations and general Cytology of the Uredineae. Ann. Bot. xviii, p. 323. 1904 TRANZSCHEL, W. Ueber die Méglichkeit die Biologie wertwechselnder Rostpilze auf Grund morphologischer Merkmale vorauszusehen. Arb. Kais. Petersburg Naturf. Gesell. xxxv, p. I. 1905 CHRISTMAN, A. H. Sexual Reproduction in the Rusts. Bot. Gaz. xxxix, p. 267. 1905 ERIKSSON, J. On the Vegetative Life of some Uredineae. Ann. Bot. xix, p. 53- 1905 WARD, H. MARSHALL. Recent Researches on the Parasitism of Fungi. Ann. Bot. xix, pe 1. 1906 BLACKMAN, V. H. and FRASER, H. C. I. Further Studies on the Sexuality of the Uredineae. Ann. Bot. xx, p. 35. 1906 MCALPINE, D. The Rusts of Australia. J. Kemp, Melbourne. 1907 CHRISTMAN, A. H. The Nature and Development of the Primary Uredospore. Trans. Wisconsin Acad. Sci. xv, p. 517. 1907 CHRISTMAN, A. H. Alternation of Generations and the Morphology of the Spore- forms in Rusts. Bot. Gaz. xliv, p. 81. 1908 OLIVE, E. W. Sexual Cell-Fusions and Vegetative Nuclear Divisions in the Rusts. Ann. Bot. xxii, p. 331. 1910 DITTSCHLAG, E. Zur Kenntnis der Kernverhaltnisse von Puccinia Falcariae. Centralbl. f. Bakt. Abt. ii, B. 28. a — VIII} IQII IQII IQII IQII IgI2 1gI2 1912 1913 1913 1913 1914 IQI4 I9QI4 1914 IQI5 1916 1917 UREDINALES 221 HOFFMANN, A. W. H. Zur Entwickelungsgeschichte von Endophyllum Sempervivt. Centralbl. fiir Bakt. Parasit. Infect. xxxii, p. 137. MAIRE, R. La Biologie des Urédinales. Prog. Rei Bot. iv, p. 109. OLIVE, E. W. Origin of Heteroecism in Rusts. Phytopathology i, p. 139. SHARP, L. W. Nuclear Phenomena in Puccinia Podophylli. Bot. Gaz. li, p. 463. FROMME, F. D. Sexual Fusions and Spore Development of the Flax Rust. Bull. Torrey Bot. Club, xxxix, p. 113. RAMSBOTTOM, J. Some Notes on the History of the Classification of the Uredinales with full list of British Uredinales. Brit. Myc. Soc. lv, p. 77. WERTH, E. and LUDWIG, K. Zur Sporenbildung bei Rost- und Brandpilzen. Ber. deutsch. Bot. Ges. xxx, p. 522. ARNAUD, G. La Mitose chez Capnodium meridionale et chez Coleosporium Sene- cionis. Bull. Soc. Myc. de France, xxix, p. 345. GROVE, W. B. The British Rust Fungi. Camb. Univ. Press. GROVE, W. B. The Evolution of the Higher Uredineae. New Phyt. xii, p. 89. FROMME, F. D. The Morphology and Cytology of the Aecidium Cup. Bot. Gaz. Ivili, p. I. KUNKEL, L. O. Nuclear Behaviour in the promycelia of Caeoma nitens, Burrill, and Puccinia Pechiana Howe. Am. Journ. Bot. i, p. 37. KURASSANOW, L. Uber die Peridienentwicklung im Aecidium. Ber. deutsch. Bot. Ges. xxxli, p. 317. MOREAU, Mme F. Les phénomenes de la sexualité chez les Urédinées. Le Botaniste, xiii, p. 145. WELSFORD, E. J. Nuclear Migrations in Phragmidium violaceum. Ann. Bot. xxix, P- 293: KUNKEL, L. O. Further Studies on the orange rusts of Azézs in the United States. Bull. Torrey Bot. Club, xliii, p. 559. ARTHUR, J. C. Orange Rusts of Awbus. Bot. Gaz. |xiil, p. 501. GENERAL BIBLIOGRAT EX 1861 TULASNE, R. C. and L. Fungi Hypogaei. Klincksieck, Paris. 1861-5 TULASNE, R. C. and L. Selecta Fungorum Carpologia. Imperial. Typograph., Paris. 1882-1913 SACCARDO, P. A. Sylloge Fungorum. Published by the author. Padua. 1884 DE BARY, A. Comparative Morphology and Biology of the Fungi, Mycetozoa and Bacteria. Eng. Trans. 1887. Clarendon Press, Oxford. 1884-97 RABENHORST, L. Kryptogamen Flora. Pilze, by G. WINTER and E. FISCHER. Ed. Krummer, Leipzig. 1887 PHILLIPS, W. A Manual of British Discomycetes. Kegan Paul, Trench & Co., London. 1892 VON TAVEL, F. Vergleichende Morphologie der Pilze. Fischer, Jena. 1892-5 MASSEE, G. British Fungus Flora. Bell & Sons, London. 1895 VON TUBEUF, K. F. Diseases of Plants. Eng. Trans., 1897. Longmans, Green & Co., London. 1897-1900 ENGLER, A. and PRANTL, K. Die natirlichen Pflanzenfamilien. Fungi, by J. SCHROTER, G. LINDAU, E. FISCHER and P. DIETEL. Engelmann, Leipzig. 1904-11 BOUDIER, E. Icones Mycologicae. Klincksieck, Paris. 1906 MASSEE, G. A Text Book of Fungi. Duckworth & Co., London. 1909 BULLER, A. H. R. Researches on Fungi. Longmans, Green & Co., London. 1909 SWANTON, E. W. Fungi and How to Know Them. Methuen, London. I910 DuGGAR, b. M. Fungous Diseases of Plants. Ginn & Co., New York. 1913 MASSEE, G. Mildews, Rusts and Smuts. Dulau & Co., London. 1913 STEVENS, F. L. The Fungi which cause Plant Disease. Macmillan Co., New York. 1918 BUTLER, E. J. Fungi and the Diseases of Plants. Thacker, Spink & Co., Calcutta. 1918 HARSHBERGER, J. W. A Textbook of Mycology and Plant Pathology. J. & A. Churchill, London. 1919 HiLEy, W. E. The Fungal Diseases of the Common Larch. Clarendon Press, Oxford. INDEX A glossary has not been prepared for this volume, but the page on which the definition of a technical term will be found ts shown in the index in clarendon type, and the same method ts used for indicating the principal reference to a family or genus. Abietineae, 18 Abutilon, 22 Accessory spore, 4; avd see Conidium Achorion Schoenteinii, 4 Adpressorium, 13, 79 Aecidiomycetes, see Uredinales Aecidiospore, 23, 200, 201, 217, 219 Aecidium, 200, 206, 214, 220 Aerotropism, 30 Agaricaceae, 33 Agaricus campestris, 31 Alcoholic fermentation, 10 e sgg., 62 Alternation of generations, 39, 188, 218 Althea, 22 Amanita crenulata, 31, 32 A. phalloides, 31 Amauroascus verrucosus, 67 American vine mildew, 81 oo Falagriae, 178, 179 (Figs. 142- 144 Amphisphaeriaceae, 154, 159 Amphispores, 205 Anemone nenorosa, 21 A. nodosa, 123 Antheridium, 2, 39, 50, 52, 53, 54, 66, 67, 69, 71, 73> 74, 85, 97, 108, 174, 181, 217, 218 *¢ Antherozoid,” 174 Anthocertis viscosa, 21 Aphanoascus cinnabarinus, 69 (Fig. 28) Apogamy, 151, 152, 209; and see Pseudapogamy Apothecium, 38, 95, 96, ror, 123, 124, 128, 129, 133 Appendages, 158, 171, 175 Arbutus, 18 Archicarp, 39, 40, 48, 50, 51, 69, 73, 98, 99, 108, III, 116, 117, £18, 119, 120, 140, 141, 144, 155, 157, 169, 170 Archimycetes, 2, 5, 15 Armillaria mellea, 1, 18, 19 Amaud, G., 212, 221 Eiht. C., 221 Ascobolaceae, 8, 9, 51, 52, 100, 116 e¢ sgg.; bibliography, 122 A scobolus carbonarius, 27, 51, 118 (Fig. 79) A. furfuraceus, 9, 30, 34, 44 (Fig. 13), 48, 49, a 99 (Fig. 58), 116 (Fig. 75), 117 (Fig. 7 A. glaber, 9; 117 A. immersus, 9, 21, 30, 46, 118 (Fig. 78) A. perplexans, 9 A. Winteri, 10, 117 (Fig. 77) PASCOGAND 33556303) 50; 557100, 70, 77, O55 ITO, HELO, et 20,0020, 123, 131,035, 138, 130, 142, 159 Ascocorticiaceae, 93 Ascocortictum, 93 Ascodesmits, 50, 51, 52, 54, 98, 101 A. nigricans, 34, 98 (Fig. 56), 101 (Fig. 59), 102 (Fig. 60) Ascogenic cells, 176 Ascogenous hyphae, 39, 40, 43, 46, 47, 53, 56, 66, 69, 75, 86, 88, 98, 106, 113, 114, 117 Ascogonium, 39; avd see oogonium Ascomycetes, 5, 6, 7, 8, 30, 34 ef sqq. Ascophanus carneus, 9,21, 46, 47 (Fig. 16), 48, 51, 118, rrg (Figs. 80, 8r) A. equinus, 21 A. ochraceus, 120 Ascophore, 38, 129 Ascospore, 3, 34, 61, 64, 79, 149 Ascus, 3, 34, 35 ef Seg, 41 et seg., 58 et seq., 89, 92,93, 95, 115, 177 Aspergillaceae, 52, 54, 55,57, 68 ef sgg. ; biblio- graphy, 75 Aspergillus herbariorum (see Eurotium herba- r20rum) Association, chromosome, 45, 113; nuclear, 46, 205, 200, 213, 214, 216 Atkinson, G. F., 50, 152 Auriculariales, 6, 183 Autobasidiomycetes, 6, 183 Autoecism, 22, 210 Bacterium vermiforme, V1 Baden, M. L.; 9; 10, 13 Balls, W. L., 28, 29, 33 Balsamia platyspora, 136 &. vulgaris, 136 (Figs. 95, 96) Banks, Sir Joseph, 210 Barberry, 210; and see Lerberts vulgaris Barclay, A., 217, 220 Barker Bal P04. 0550705 Late BAe IN, GIs Oy Wey WO, Mtg De At Dyin 3R5 Bil 40, 50, 70, 75, 84, 102, 103, 107, 187, 188, 195, 210, 222 Basidiomycetes, 5, 6, 7, 8, 183 Basidiospore, 3, 183, 186, 190, 192, 193,197, 207, 20 Badin: 35 163; 1955, £80; 103) 213 Bayliss, W. M., 66 Berberts vulgaris, 203 (Fig. 176), 210 Berkeley, M. J., 126, 127, 149, 152, 187, 195 Bernard, N., 17, 18, 20 Bertero, 126 Betula alba, 21 Betulaceae, 18 Bezssonoff, M. N., 86, go Bittengew bl. 12.625. 82750 Toe Biological species, 22 e¢ sgg., 161 Biseriate spores, 36, 37 (Fig. 4) Blackman, V. H., 198, 199, 201, 204, 206, 212, 213, 214, 215, 216, 217, 220 224 Blackman and Fraser, H.C. I., 48,84, 85, 89, 111, I12, 116, 200, 201, 202, 212, 214, 215, 216,220 and Welsford, E. J., 13, 20, 48, 141, 147, 148, 152 Blakeslee, A. F., 27 Bletilla, 17 B. hyacinthina, 17 Blight, see Erysiphaceae Boleti, 19 Botrytis, 14, 31 B. cinerea, 13, \4 Boudier, E., 113, 130, 222 Boudiera hypoborea (see Ascodesmis nigricans) Boulanger, E., 138 Bower, F. O., 20 Brachymeiosis, 44 Brand fungi; see Ustilaginales Brand-spore, 183, 184, 187, 191, 192, 194 Brefeld, ©., 30, 33, 40, 50, 72, 75, 120, 187; 188, 195 Brierley, W. B., 77, 162, 163 Bromelia, 39 Bromus adoénsis, 24 . arduennensis, 24 . commutatus, 24, 25 . ‘hordeaceus,” 24, 25 . interruptus, 24 . mollis, 24, 25 . FACEMOSUS, 24, 25 secalinus, 2 . velutinus, 24 Brooks, 1B ite; OA Brooks, W. E. St J., see Fraser and Brooks Brown, W., 13, 20 Brown, W. H., 105, 107, 116 132 Bryophyta, 161 Buchanan, J., 127 Bucholtz, F., 97, 137, 138 Budding, 5, 60, 62, 93, 185, 199 Builliard, P., 40 Bulgaria polymorpha, 35, 125 Buller ee bl oka, eons Bunts, see Ustilaginales Burgeff, EL, 017, 20 Butler, E. J., 222 ba bs bate bs at By BA, DD Caeoma, 201, 202, 213, 214, 215 Caeoma nitens (see Kunkelia nitens) ** Californian bees,” 11 Calluna vulgaris, 16 Calosphaeria, 165 C. princeps, 165 Capnodium, 12 Carruthers, D., 43, 44, 48, 130 Caryophyllaceae, 21, 191 Cattleyeae, 17 Cavara, F., 101 Cavers, F., 20 Celidiaceae, 100, 124 Celidium varians, 125 Cell-fusion, 215, 216 Cenangiaceae, 100, 124 Central body, 88 Ceratomyces rostratus, 173 (Fig. 134) Ceratomycetace ae, 180 Ceratostoma brevirostre (see Melanospora Zobeliz) Ceratostomataceae, 154, 159 INDEX Cercospora, 163 Chaetomiaceae, 154, 155 et seq. Chaetomium chlorinum, 155 C. fimete, 54, 155 C. Kuntzeanum 35 (Fig. 2), 155 (Fig. 113), 156 (Fig. 114) C. pannosum Wallr., 155 (Fig. 112) C. spirale, 140, 155 Chambers, H. S., see Fraser and Chambers Chemotropism, 14, 27, 186 Cherry-leaf-scorch, 163 Chlamydococcus pluvialis, 31 Chlamydospore, 4, 57 Choiromyces maeandriformis, 137 Christman, A. H., 201, 203, 206, 208, 210, 212, 215; 216, 217, 220 Chromatin, 44, 45, 94 Chromosome association, 45, 113 Chromosomes, 43, 44 (Fig. 13), 89, 106, 109, 112, 113, 114 (Fig. 71), 115 (Miosoge ae I£7, 130, 164, 179, 180, 212 Chrysomyxa, 204, 219 C. Led, 23 C. Rhododendri, 23 Chrysopsora, 198, 218 C. Gynoxidis, 219 Chytridium vorax, 31 Cidaris, 129 Clamp-connections, I Clarks alee 2033 Classification of Fungi, 5 Claussen, P., 43, 46, 98, ror, 102, 104, 105, 107 Clavate paraphyses, 38 Claviceps purpurea, tO, 21, 151 Coenogamete, 2 Coleophora laxicella, 123 Coleoptera, 171 Coleosporiaceae, 218, 220 Coleosporium, 198, 204, 212, 220 C. Senecionis, 212 (Fig. 189) C. Sonchi, 196 (Fig. 164), 207 (Fig. 183) C. Sonchi-arvensis (see C. Sonchi) Coleroa Potentillae, 158 (Fig. 118) Collema pulposum, 51, 52 Colletotrichum Lindemuthianum, 14 Compsomyces verticillatus, 176 (Fig. 137) Conidiophores, 4, 70, 72, 80 Conidium, 4, 15, 24, 57, 58, 60 (Fig. 21), 70, 72 (Fig. 31), 74, 79, 80, 90, 98, 118, 125, 133, 145, 149, 151, 161, 166, 170, 185, 186, 194 : Conjugate division, 46, 177, 186, 201, 202, 204, 206 Conjugation, 59, 63, 186, 189, 190, 194, 208 Coprinus, 9 C. curtus, 31 C. niveus, 31 C. sterquilinus, 9 Coprophilous Fungi, 8, ro8, 112, 116, 156 Cordyceps, 10, 149 C. Barnesiz, 151 (Fig. 111) - C. capitata, 151 C. militaris, 150 (Fig. 110) > C. ophioglossoides, 34, 150 (Fig. 110), 151 C. stmensis, 149 a Coremium, 4 a Coreomyces, 174 Cortinarius, 19 a INDEX 225 Coryne, 125 C. sarcotdes, 125 Cronartiaceae, 218, 219 Cronartium, 219 C. asclepiadeum, 197 (Fig. 165) Cruciferae, 21 Ctenomyces serratus, 67 (Fig. 27) Cutting, E. M., 9, 13, 48, 119, £22 Cyathea, 18 Cystopus, 15 C. candidus, 15, 21 Cytology of the Ascomycetes, 40 ef sqq. of the Ustilaginales, 187 e sgq. of the Uredinales, 201 e¢ sgg., 211 et sgq. Cyttaria, 125 C. Berterot, 126 C. Darwinit, 125, 127 C. Gunnzz, 126 (Fig. 87) C. Harzoti, 127 C. Hookert, 127 Cyttariaceae, 100, 125 e¢ sgg.; bibliography, 127. Czapek, F., 7, 12 Wale; Es. 13, 48, 66,67, 68, 71, 76 Dangeard, P. A., 41, 44, 55, 60, 61, 67, 68, 69, 73, 74, 75, 76, 86, 87, 89, 94, 101, 105, ROFMuuyselZO 20,0022, 140, 152, 050, 057, 158, 188, 189, 192, 194, 195 Dasyscypha, 123 D. clandestina, 21% D. Willkommit, 123 Dawson, M., 32, 33, 166, 169, 170 Debaryomyces globosus, 64 Dehiscence of ascus, 36 e¢ sq. Delitschia furfuracea, 35 (Fig. 2) Dermataceae, 124 Desmotascus, 39 Dey see Ke, 20 Diatrypaceae, 154, 165 Diedicke, H., 23, 26 Dietel, P., 222 Digby, L., see Farmer and Digby Dikaryon, 46, 201 Dimeromyces Africanus, 174 (Fig. 135) Diplophase or diploid phase, 3 Dipodascus, 54, 57, Ot D. albidus, 60 (Fig. 22), 61 (Fig. 23) Discomycetes, 6, 49, 50, 52, 95 e¢ sgq-, 181 Dittschlag, E., 200, 202, 203, 220 Division, conjugate, 202 Doassansia, 187 D. Alismatis, 194 (Fig. 162) D. deformans, 194 Dadsewb O90, 10) 13, 40, 90, 116, 117, 118, 122 Domaradsky, M., 71, 76 Dothiuea virgultorum, 153 Dothideaceae, 152 Dothideales, 6, 140, 142, 152 Dufrénoy, J., 20 Duggar, B. M., 222 Dumee, P., and Maire, R., 220 Durand, E. J., 132 Early investigators (Ascomycetes), 40 Ectoparasite, 80 Eidam, E., 40, 58, 61, 67, 68 G.-V. Llaphomyces, 19 £. granulatus, 77 E. vartegatus, 77 Elaphomycetaceae, 8, 57, 77 Emericella erythrospora, 68 Lmpusa, to Endogenous spore, 3 Endomyces, 35, 53, 58 e¢ sqq- £. decipiens, 63 (Fig. 24) E. fibuliger, 59 (Fig. 20), 60 (Fig. 21), 63 (Fig. 24) E. Magnusit, 59 (Fig. 20), 60, 63 (Fig. 24) EY. Malt, 57 Endomycetaceae, 52, 53, 55, 57 e¢ sgg.; biblio- graphy, 61 Endophyllum, 199, 208, 217, 218, 219 £. Euphorbtae, 209, 217 E. Sempervivi, 202, 208 (Fig. 185), 209 (Figs. 186, 187), 217 Endophytic parasite, 15, 79, 80 Endospore, 62 Endotrophic mycorhiza, 16 Engler, A., and Prantl, K., 222 Entomophthorales, 5 Entyloma, 186, 187 E. Glaucit, 194 (Fig. 162) L. Nynipheae, 194 Epichloé, 149 Epiphytic parasite, 15 Epiplasm, 35, 49 Eremascus, 40 E. albus, 58 (Fig. 18) E. fertilis, 58, 59 (Fig. 19), 63 (Fig. 24) Ericaceae, 18 Eriksson, J., 23, 26, 211, 220 Erinella apala, 21 Erysiphaceae, 15, 23, 52, 53, 55, 78, 79 et 5qq., 181; bibliography, 89 Erysiphales, 6, 56, 78 et sgg., 181 Erysiphe Cichoracearun, 87 E. communts (see EL. Polygon) £. Graminis, 24, 25, 79, 82 E. Martii (see E. Polygont) E. Polygont, 42, 82 (Fig. 39), 86 (Fig. 43), 87 £. taurica, 80 E. tortilis, 83 (Fig. 40) Euglena viridis, 31 Euphorbia sylvatica, 209 Eurotium, 7, 10, 53, 70 LE. Aspergillus glaucus (see E. herbariorum) E. herbariorum, 20, 69, 7° (Fig. 29), 71 (Fig. 30) E. nigrum, 12 EE. Oryzae, 12 E.. repens, 32, 48 Exoascaceae, 5, 15, 16, 54, 55, 93 e¢ seg. Exoascales, 6, 36, 55, 56, QI e¢ sg. E-xoascus, 15, 16, 93 Lt. Betulae, 215 E. deformans, 91, 92 (Fig. 48) Exobasidium, 16 E. Rhododendri, 21 Exogenous spore, 3 Exotrophic mycorhiza, 16, 18 Facultative parasites, 6, 13 Facultative saprophyte, 6 15 226 Fagaceae, 18 Fairy-rings, 7 Farmer J. B., and Digby, L., 48 Fasciculate spores, 36 Fatty substratum, fungi on, 10 Faull, J. H., 46, 49, 138, 172, £78, 179, 180, 182 Federley, jet +» 190, 105 Fermentation, alcoholic, 10 et sgg., 62 Fertile cell (Uredinales), 200 Fertilization, 2, 3 in Ascomycetes, 41, 57; 176 in Uredinales, 205 Fisch, C., 146, 152 Fischer, E., 127, 222 Fischer von Waldheim, A., 187, 195 Fitzpatrick, 11. M., 128, 129 Foéx, M., go Frank, B., 20, 146, 152, 164 Braser shen Ga less 244) mila and Blackman, V. H., see Blackman and Fraser and Brooks, W. E. St J., 117, 122 and Chambers, H. S., 76 and Welsford, E. J., 115 Freeman, E. M., and Johnson, E. C., 26, 27 Fromme, F. D., 200, 201, 221 Fruit gall, 184 Bultony Hes Ro 145) 20; 28,928 Fungi, the, 1 Fungi imperfect, 3, 7, 163 Fusicladium, 161 F.. dendriticum, 161 fF. Pyrinum, 16% Fusion, cell, 1, 57 e¢ sgq., 64, 186, 215, 216; in the ascus, 41 ef sgg., 47, 1303 nuclear, 45 et syg-, 48, 59, 60, 86, 87, TOI, 105, 109, WN, Wits Wy, THOR WAI, TA, TG, i'7%f, 188 ef sgq., 206 e¢ sqq- 85, 87, IOI, 104, Galactinia succosa, 42 Gallaud, I., 20 Gametophyte, 40 Gasteromycetes, 6 Gastrodea elata, 18 Geaster, 19 Gemini, 43 (Fig. 11) Genea, 97 G. hispidula, 135 (Fig. 94) G. Klotzschit, 135 (Fig. 94) G. sphaerica, 135 (Fig. 94) Gentianaceae, 18 Geoglossaceae, 97, 99, 127, 131 ed seq. Geoglossum difforme, 35 (Fig 2) G. hirsutum, 13% (Figs. 91, 92) Geotropism, 32 Germ-pore, 2, 200 Germ-tube, I, 13, 14, 28, Ginger-beer plant, 11 Gjurasin, S., 41 Gleba, 135 Gnomonia, 15, 51, 163 G. erythrostoma, 163 Gnomoniaceae, 154, 163 ef seg. Goddard, H. N., 13 Gooseberry mildew, 8t Graves, A. H., 14, 20, 28, 29, 33 29, 47) 149 INDEX Green, J. Reynolds, 12 Green Algae, 49 Grove, W. B., 211, 221 Guilliermond, A., 43, 56, 58, 59, 60, 61, 63, 64, 55 (WO, Wein ties, rele CGutlliermondia, 57 G. fulvescens, 64 Gwynne-Vaughan, H. C. I.; see Fraser Gymnoascaceae, 52, 54, 55, 57, 06 e¢ sgg.; biblio- graphy, 68 Gymmoascus, 53, 54, 66 (Fig. 26) G. candidus, 67 (Fig. 27) G. Reesiz, 21, 66, 67 (Fig. 27) Gymmnoconia tnterstitialis, 208 Gymnosporangium, 219 G. clavar jacforme Rees, 198 (Figs. 167, 168), 199 (Fig. 169), 200, 212, 213 (Fig. 190) Gyromilra, 129 slau), Je JO)5 73} Hall, J. G., see Stevens and Hall Hansen, E. C., 65 Haplophase or haploid phase, 3 Harper, R. A., 41, 42, 43) 45) 47, 48, 49, 82, 85, 86, 87, 88, 89, 104, 105, 106, 107, 117, 122, 185, 186, IQI, 192, 195 and Holden, R. J.; see Holden and Harper Harshherger, J. W., 222 ~ Hartig, R., 159 Hasselbring, H., 33 Haustorium, 15, 79, 80 Heliotropism, see phototropism Helotiaceae, 97, 100, 122 ef seg. Helotium, 123 flelvella, 129 HT. crispa, 2, 43, 44 (Figs 12 (Fig. go) H1. elastica, 43, 129 Helvellaceae, 97, 127, 129 ef seg. Helvellales, 6, 32, 36, 99, 127 Hemibasidiomycetes, 6, 183, 184 e¢ sgg. flemiieia, 219 Hemi-parasite, 6 Hemi-saprophyte, 6, 13 Hendersonia, 163 Heteroecism. 22, 210° Higgins, B. B., 160 Highley, P., 108 Hiley. W. ia 222 Hoffmann, A. W. H., 208, Hofmeister, W., 32, 33 Holden, R. J., and Harper, R. A., 207, 213, 220 Hop mildew, 84 flornia, 1 H-piece, I Humarta carbonigena, 115 H. granulata, 48, 50, 111 (Fig. 68), 113 HI. Roumeguert, 115 H. rutilans, 36 (Fig. 3), 41 (Fig. 8), 43 (Figs 10, 11); 44, 47, 48, 49 (Fig. 17), 96 (Fig. 53), 113 (Fig. 69), 114 (Figs. 70, 71), 115 (Figs. 72-74) Hyaline’ cell, 4 Hydnaceae, 33 Hydnum, 21 Hydrotropism, 14, 29 ), 48, 129, 130 209, 220 67), 112 (Fig. INDEX Hymenial layer, 36, 96 Hymenium, 3, 78, 95, 136, 137, 139 Hymenogasteraceae, 8, 19 Hymenomycetes, 6, 32 Hypertrophy, 15, 16, g1, 184, 196 Hypha, 1, 41, 56, 58, 60, g1, 95, 101, 103, 106, 129, 146, 162, 167, 199 Hyphomycetes, 7; and see Pungé imperfecti flypochnus, 17 fypocopra, 140, 156 fly pocrea, 149 Hypocreaceae, 143, 146 ef seg.; bibliography, 152 Hypocreales, 6, 140, 142, 143 Hypodermataceae, 134 Hypogeal fungi, 8, 77, 135 Hypomyces aurantius, 143 H. lateritus, 140, 143 Hypothecium, 95 Hypoxvlon coccineum, 166 (Fig. 123) Hysteriaceae, 134 Hysteriales, 6, 96, 100, 133 likenayS-, 75, 70, o4 Inordinate spores, 36 Intercalary cells (Uredinales), 86, 200, 202 lsaria, £50 Johannesberg yeast II, 63 (Fig. 24), 65 Johnson, E. C., see Freeman and Johnson Jolivette, H. D. M., 30, 33 uelsii'©:; 61 Kempton, F. E., 1 Kephir, 11 Kidston, R., and Lang, W. H., 1 Kienitz-Gerloff, F., 172 KihIman, O., 102, 107, 144, 146 Klocker, A., 62, 65, 73, 76 and Schidnning, H., 12 Knowles, E. L., 94 Keay, Is 32; 33 Konokotine, A. G., see Nadson and Konokotine JKoumiss, 12 Kunkel, L. O., 221 Kunkelia nitens, 208, 209, 218 Kurassanow, L., 202, 221 Kusano, S., 18, 20 Kuyper, H. P., 75, 76 Labiatae, 18 Laboulbenia, 46, 17% L. chaetophora, 171 (Fig. 131), 178, 180 (Fig. 145) L. elongata, 172 (Fig. 132) L. Gyrinidarum, 178 L. inflata, 177 L. triordinata, 171 (Fig. 130) Laboulbeniaceae, 180 Laboulbeniales, 6, 15, 35, 51, 52, 54, 142, 171 et sgg.; bibliography, 182 Lachnea cretea, 27, 51, 52, 109, 110 (Fig. 66) L. scutellata, 109 PEMETCOLEas O20) (Fig. 7); 48, 40, 59). 52; 95 (Fig. 52), 108 (Fig. 65) Lactarius piperatus, 1g Lagerheim, G. de, 61 Lanceolate paraphyses, 38 207, Lang, W. H., 20 and Kidston, R. Larch canker, 123 Larch moth, 123 Lavatera, 22 Lentinus epideus, 7, 3% Leotia lubrica, 131 (Fig. gt), 132 Lepeschkin, W. W., 65 Leptosphaeria, 162 L. Lemaneae, 162 (Figs. 121, 122) Levine, M. N., see Stakman, Piemeisel, and Levine Lewton-Brain, L., 34, 151; 152 Lichens, 52, 161, 181 Light, formative influence of, 31 Liliaceae, 18 Lindau, G., 222 Lophiostomataceae, 154, 160 Lophodermium Pinastri, 134 Ludwig, K., see Werth and Ludwig Lutman, B. S., 186, 189, 192, 193, 194, 195 Lychnts alba, 192 L. dwotca, 192 Lycopodium, 18, 19 ; see Kidston and Lang McAlpine, D., 195 M«Beth, 1. G., and Scales, F- M-., 12 McCubbin, W. A., 43, 130 Maire, R., 42, 43, 44, 114, 116, 130, 143, 201, 220 Malva, 22 Marattiaceae, 18, 19 Marchal, E., 23. 26 Marchand, H., 66 Marchantia, 4 Marryat, D.C. E., 25, 27 Marshall, W., 210 Massee, Gz, 20; 265 ‘511; 545 O75 03) 132, 035, Majeh wy, His un, Boe and Salmon, E. S., 9, 12, 158 Massee, I., 191, 195 Mayr, H., 146 Meiosis, 3, 43, 53, 209, 212 Melampsora, 218, 219 M. belutina, 197 (Fig. 166) M. Rostrupi, 201 (Fig. 174), 215 Melampsoraceae, 218, 219 Melanospora, 144 MM. daninosa, 144 M. parasitica, 144 MM. Zobelit, 144 Melhus, I. E., 20 Meltiola, 12 M. Penzigt, go Merulius lacrymans, 7 Mesospore, 197 Microsphaera, 82, 83 (Fig. 40) M. Alnz, 81, 88 Microsporon furfur, 4 Microthyriaceae, 78, 79, 91 Migration, nuclear, 48, 114, 186, 201, 208, 214 Mildew, white, see Erysiphaceae Mitrula laricina, 37 (Fig. 4), 96 (Fig. 54) Miyabe Kingo, 163 Miyoshi, M., 14, 20, 29; Molliard, M., 9, 12 Mollisiaceae, 100, 122 e¢ seq. 25 33 228 INDEX Monascus, 46, 74 M. Barkert, 74 (Fig. 34) M. heterosporus, to, 68 M. purpureus, 75 (Fig. 35) M. X., 75 (Fig. 35) Monilia, 124 M. albicans, 4 M. (Sclerotinia) cinerea, 22 Monoblepharts, 2 Monotropa Hypopitys, 19 Monoxeny, 21 Morchella, 129 MW. esculenta, 44, 130 M. vulgaris, 130 (Fig. go) Moreau, F., 146 Moreau, Mme F., 208, 209, 212, 213, 216, eon Mucor, 9, 10, 27, 32 M. Mucedo, 27, 29, 32 MM. racemosus, 12 M. stolonifer (see Rhizopus nigricans) Mucoraceae, 7 Mucorales, 5, 22, 30 Muriform spore, 4, 34 Mycelium, 1, 15, 17, 18, 34, 58, 79, 91, 103, 189, 190, 192, 194, 196, 197 Mycoplasm, 211 Mycorhiza, 16 ef sg9@. Mycosphaerella nigerristigma, 160 Mycosphaerellaceae, 154, 160 Nadson, C. A., and Konokotine, A. G., 66 Nectria, 19, 145 LV. cinnabarina, 14, 145 (Fig. 105) Nectriaceae, 143 eZ seqg.; bibliography, 146 Neger, F. W., 89 Nichols, M. A., 47, 142, 144, 146, 159, 160 Nienburg, W., 147, 148, 152 Non-motile spore, 4 Nuclear association, 46, 205, 206, 213, 214 Nuclear division (Uredinales), 211 Nuclear fusion, 45 e¢ sgq., 48, 59, 60, 86, 87, 1or, TO5, 109, 121, 129, 149, 177, 188 ef sqq., 206 et sqq. Nuclear migration, 48, 114, 186, 201, 208, 214 Nuclei, paired, 42, 46, 47, 60, 75, 177, 186, 201 Oak mildew, 8 Obligate parasite, 6, 14 Ochropsora, 198, 220 Odontoglossum, 17 Ozdiopsis taurica, 80 Oidium, 4, 57, 58, 80 Ozdium, 80 O. Quercinum, 81 O. Tuckeri, 80 Olive, E. W., 76, 208, 210, 212, 216, 220 Oliver, F. W., 19 Olpidium, 15 Oltmanns, F., 155, 156 Onygena equina, 21, 76 Onygenaceae, 57, 76 et sqq. Oogonial region, 39, 119 Oogonium, 2, 39, 41, 51, 52, 54, 67, 71, 74, 75) 84, 85,87, 98, 101, 103, 112, 176, 180, 215, 218 Oomycetes, 5 Ophioglossaceae, 18 Orcheomiyvces, 17 Osmotropism, 30 Ostiole, 38 Otidea aurantia, gs (Fig. 51), 115 Otomycosts aspergillana, 20 Overton, J. B., 120, 121, 122 Page, W., 155 Paraphyses, 3, 36, 37, 38 Parasite, 6 facultative, 13 obligate, 14 Parasitism, 6, 13 ef sgg.; bibliography, 19 ; specialization of, 20 ef sgg. (bibliography, 26), 211 Parte ss Ones Patellariaceae, 96, 100, 124 Penicillium, 7, 10, 72 P. crustaceum (see P. glaucune) P. glaucum, 12, 20, 31, 72 (Figs. 31, 32) P. vermiculatum, 73 (Fig. 33) 2. Wortmanni, 73 Peniston, A., see Wagner and Peniston Peridermium, 202 Peridium, 38, 39 Periphyses, 38, 140 Perisporiaceae, 79, 90 Perithecium, 38, 68, 81, 82, 83, 86, 87, 88, go, QT, 137) 145, 148, 151, 154, 156, 157, 158, 162), LOO, U7 Ls ly Peronospora Euphorbiae, 21 P. parasitica, 31 Peronosporales, 5 Persoon, C. H., 210 Peyritschiellaceae, 180 Peztza rutilans (see Humaria rutilans) P. tectoria, 115 P. theleboloides, 115 P. vesiculosa, 41, 49, 115 Pezizaceae, 50, 52, 100, 107 e¢ sgg., 144; biblio- graphy, 116 Pezizales, 6, 36, 96, 97, 99, 100 et sgq. Piette Wes 32 Phacidiaceae, 133 Phacidiales, 6, 96, 100, 132 et seg. Phillips, W., 222 Phoma, 1, 16, 163 Phototaxis, 31 Phototropism, 14, 30 Phragmidium, 197, 199, 202, 219 P. bulbosum, 196 (Fig. 164) P. Potentillae- Canadensis, 203 (Fig. 178) P. Rubz, 204 (Fig 179), 205 (Fig. 180) P. speciosum, 201 (Fig. 172), 212, 215 (Fig. 195) P. subcortictum, 204, 216 P. violaceum, 198 (Fig. 168), 200, 201 (Fig. 173), 204 (Fig. 179), 205 (Fig. 180), 206 (Fig. 182), 213 (Fig. 191), 214 (Fig. 192), 215 (Fig. 194) Phycomyces, 32 Phycomycetes, 5 Phyllactinia, 35, 45, 82, 83, 87 P. Corylea, 21, 45 (Fig. 14), 79, 80, 83 (Fig. 40), 87 (Fig. 44), 88 (Figs. 45) 46), 89 (Fig. 47) INDEX Phyllosticta, 32 Phylogeny, 49 e¢ sg7-, 63, 96 et sgg-, 140, 180, 188, 216 Phytophthora infestans, 21 Piemeisel, F. J., see Stakman, Piemeisel, and Levine Pilacre faginea, 21 Pilobolus, 8, 9; 10; 30 - Pinus sylvestris, 134, 206 Piptocephalis Fresentana, 22 Plectascales, 6, 56 e¢ sgq-, 181 Plectomycetes, 6, 52, 53, 55 ¢ 599: Pleospora, 1, 23, 35 (Fig. 1), 161 (Fig. 120) P. herbarum, 161 Pleosporaceae, 154, 161; bibliography, 163 Plowright, C. B., 185, 187, 193, 195, 220, 222 Plowrightia morbosa, 153 Podocrea, 149 P. alutacea, 149 Podosphaera, 53 Podospora, 157 P. anserina, 158 P. coprophila, 21 P. curvicolla, 36 P. vrsuta, 140, 157 (Fig. 115) P. minuta, 35 (Fig. 2) P. pleiospora, 36 Podostroma alutaceum (see Podocrea alutacea) Poirault, G., and Raciborski, M., 220 Pole Evans, I. B., 26, 27 Polyascomyces, 177 P. Trichophyae, 177 (Fig. 140) Polyphagus Euglenae, 3% Polyporaceae, 33 Polyporus squamosus, 31 Polystictus cinnabarinus, 33 Polystigma, 51, 146 P. rubrum, 21, 48, 141 (Fig. 102), 146, 147 (Figs. 106, 107), 148 (Figs. 108, 109) Polyxeny, 21 Poronia punctata, 32, 166, 168 (Figs. 125, 126), 169 (Fig. 127) Prantl, K., see Engler and Prantl Prévost, B., 187, 195 Primary uredosorus, 203, 216 Promycelium, 183, 198 Protascus colorans (see Wolkia decolorans) Protobasidiomycetes, 6, 183, 196 et sgq- Prunus pennsylvanica, 160 Pseudapogamy, 2, 3, 48, 71,109, 113, IT4, 117, I1g, 130. 149, 187, 205 Pseudoparenchyma, I Pseudoperidium, 202, 219 Pseudopeziza Trifolit, 123 Psilotaceae, 18 Pteridophyta, 18, 91, 161, 196 Puccinia, 219 P. Adoxae, 207 P. Buxi, 208 P. Caricis, 196 P. Claytoniata, 200 P. dispersa, 15, 23 P. Falcariae, 200, 202, 203 (Fig. 177) P. fusca, 211 P. glumarum, 25 P. Graminis, 23, 26, 203 (Fig. 176), 210 P. Malvacearum, 22, 29, 31, 208 (Fig. 184) to to \o Puccinia (cont.) P. Peckiana, 209 P. Phragmitis, 200 P. Poarum, 31, 199, 200, 201, 202 (Fig. 175); 208, 214 P. Podophylli, 206 (Fig. 181), 208 (Fig. 184) P. suaveolens, 199 P. transformans, 208 P. vexans, 204 Pucciniaceae, 218, 219 Pucciniastrum, 204 ~ Puffing, 36, 127 Puya, 01 Pycnidium, 1, 4 Pyrenomycetes, 6, 47, 50, 51, 52, 139 ¢? 599-5 181 Pyronema, 50, 51, 52; 102 | P. confluens 21, 40, 42) 43, 445 46 (Fig. 15), 98 (Fig. 57), 102, 103 (Fig. 61), 104 (Fig. 62), 105 (Fig. 63), 106 (Fig. 64) P. omphaloides (see P. confluens) Pyronemaceae, 100, I0I ef sgq. 3 bibliography, 107 Pythiun, 19 P. de Baryanum, 27 Rabenhorst, L., 222 Raciborski, M., 45 and Poirault, G.; see Poirault and Racli- borski Ramlow, G., 9, 13, 46, 47, 118, 119, 121, 122 Ramsbottom, J., 9, 20, 62, 221 Ranunculaceae, 18 Ranunculus ficaria, 203 (Fig. 176) Rawitscher, F., 187, 188, 189, I1g0, 191, 193, 194, 195 Rayner, M. C., 16, 20 Reactions to stimuli, 27 ef sgg.; bibliography, 33 Receptacle, 171, 175 Red Algae, 49, 50, 162, 172, 173, 181 Reproduction, sexual, 2; avd see conjugation, fertilization, pseudapogamy ; non-sexual, 43 and see ascospore, basidiospore, conidium Reticulate spore. 5 Rhizina, 52, 128 R. inflata, 128 R. undulata, 51, 128 Rhizinaceae, 99, 127 ef 599-5 bibliography, 129 Rhizoctonia, 158 Rhizoctonia, 17, 18 Rhizomorph, I Rhizopus, 10 R. nigricans, 12, 27 et Sgq-, 32 Rhododendron ferrugimeum, 21 R. hirsutum, 2 Rhynta, \ Rhyparobius, 36 R. brunneus, 121 R. ( Thecotheus) Pelletiert, 120 R. polysporus, 121 Rhytisma Acerinum, 21, 35 (Fig. 2), 133 (Fig. 93 Robinson, W., 14, 20, 29, 31, 33, 199 Roestelia, 202 Rosellina quercina, 140, 1 58 Rouppert, C., 128, 129 Rubus tdaeus, 20 Rust-fungi, see Uredinales 230 INDEX Saccardo, P. A., 222 Saccharomyces, 62, 63 (Fig. 24) S. pyreformis, vi Saccharomycetaceae, 7, 11, 52, 54, 59.5 bibliography, 65 Saccharom rycodes Ludwigit, 65 Saccharomycopsts capsularis, 63 (Fig. 24) Saccobolus violascens, 120 (Fig. 82) Sachs, J. von, 32, 33, 49 Saké, 12 Salicaceae, 18 Salmon, E. S., 23, 25, 26, 79, 89, 90; see also Massee and Salmon Samsu, 74 Sands, M. C., 88, 89 Sappin-Trouffy, P., 204, 205, 212, 220 Saprolegniales, 5 Saprophytes, 6 Saprophytism, 6, 7 e¢ sgy.; bibliography, 12; specialization of, 20 ef sgq. Sarcodes sanguinea, 19 Scales, F. M., 13; see also M°Beth and Scales Schikorra, W., 46, 74, 75, 76 Schidnning, H., 63, 65; see also Klocker and Schidnning Schizanthus Gr ‘ahamt, 2% Schizosccharomyces mellace?, 63 (Fig. 24), 64 S. octosporus, 63 (Fig. wy 64 (Fig. 25) S. Pombe, 64 Schmmitz, F., 41 Schoeler, N. P., 210 Schrenk, H. von, 12 Schroter, J., 222 Schwanniomyces occidentalis, 64 Sclerotinia, 123 S. bulborum, 122 S. cinerea, 123 S. fructigena, 123 S. Ledz, 22 S. sclerotiorum, 123 S. tuberosa, 21, 123, 124 (Fig. 86) S. Vacciniz, 124 Sclerotium, I, 124, 150, 152 Scolecite, 39, 50, 99, 116 Seaver, F. J., 146 Selaginella, 18 Sepultaria, 97 S. coronaria, 37 (Vig. 5), 97 (Fig. 55) Sexual feproduction, 2Toats and see conjugation, fertilization, pseudapogamy Sharp, L. W., 221 Sheath, 69, 85, 148 Smuts, see Ustilaginales Soil, fungi on, 7 Solanaceae, 18, 21 Solanum, 18 Solms Laubach, H. zu, 184, 195 Soot fungi, 12 Sooty- mould, go Sordaria, 9, 10, 30, 38 (Fig. 6), 139 (Fig. 100) S. Brefeldii, 158 S. coprophila, 138 S. fimicola, 140 (Fig. tor) S. fimiseda, 140, 157 S. globosa, 158 S. macrospora, 21, 140, 57 (Fig. 116) Sordariaceae, 8, 154,156; etsgq. bibliography, 158 56, 57, 62 e¢ Sore-skin fungus, 28 Sorosporium, 187 Sorus, 184, 196 Spathularia clavata, 131 (Figs. 91, 92) Specialization, 20 e¢ sgg., 211 Spermatial hypha, 146, 163, 199, 207 Spermatium, 39, 146, 164, 173, 174, 199 : Spermogonium, 147 (Fig. 106), 163, 198 Sphacelotheca, 187 Sphaeria, 127 Sphaeriaceae, 154, 158 Sphaeriales, 6, 140, 142, 153 ef seg. Sphaerosoma, 128, 129 S. fuscescens, 129 (Fig. 89) S. Janczewskianum, 128 (Fig. 88), 129 Sphaerotheca, 52, 53, 83 S. Castagnei (see S. Hunt) S. Humuli, 41, 42 (Fig. 9), 84 (Fig. 41), 85 (Fig. 42) S. mors-uvae, 81, 82, 86 S. pannosa, 80 (Fig. 38) Spore, 1,3) 4, 35, 49, LOL, 072.090 Spore-ball, 184, 187, 194 Spore-formation, 48, 49 Spore forms, omission of, in Uredinales, 207 Spore mother-cell, 3, 35 Sporidium, 198 Sporormia intermedia, 157 (Fig. 117) Sprouting, 5 Stakman, E. C., Piemeisel, F. J., and Levine, M. N., 26, 2 Staling substances, 27 Stalk, of antheridial branch, 39, 87, 88; of archicarp, 85, 87, 88 Sterigma, 183 Sterile cell (Uredinales), 200, 20 Stevens, Hi) 107,)30;) 222 and Hall, J. G., Stictaceae, 132 Stigeosportum, 19 Stigmatomyces Baert, 174, 175 (Fig. 136), 176, 177 (Fig. 139) S. Sarcophagae, 177, 178 (Fig. 141) Stimuli, reactions to, 27 e¢ sgg.; bibliography, 28, 32, 33 33 Stoppel, R., 58, 61 Strasburger, E , 31, 33 Strawberry mildew, 84 SRS Sp (Gray Sin By BR Strickeria, 1, 142 (Fig. 104), 159 (Fig. 119) Stroma, I, 32, 140, 145, 149, 150, 166, 168 Sub-hymenial layer, 3, 95 Substrata, fatty, 10 Swanton, E. W., 222 Symbionts, 6 Symbiosis, 6, 16 e sgg.; bibliography, 19 Synchytrium, 10 S. aureum, 21 Synkaryon, 201 Tapesia fusca, 123 Taphrina, 15, 93 ‘ 7. aurea, 92 (Fig. 49), 93 (Fig. 50) T. Cerast, 94 T. Kusanoi, 94 Tavel, F. von, 40, 222 Teleutosorus, 205, 206 INDEX Teleutospore, 23, 196, 197, 205, 206, 212, 218, 219, 220 Teleutospore cell, 183, 197, 205 Terfezia olbiensis, 77 (Fig. 36), 78 (Fig. 37) Terfeziaceae, 8, 57, 77 Miaxter, R., 71; 172, 1735 174) 175) 176, 177; 178, 179, 180, 181, 182 Thelebolus, 50 T. stercoreus, 120 (Fig. 83), 121 (Figs. 84, 85) T. Zukalit, 122 Thermutis orlutina, 16 Thielavia basicola, 68 Thiessen, F , gt Thom, C., 76 Tieghem, Ph. van, 40, 102, 107 Tilletia, 187, 193 T. foetens, 193 T laevis, 194 T. Vvritecz, 185 (Fig. 148), 187, 193 (Fig. 161) Tilletiaceae, 193; bibliography, 195 Torulaspora Roset, 64 Tragopogon pratensis, 189 Tranzschel, W., 211, 220 Tremellales, 6, 183 Tremellodon, 33 Trichogyne, 39. 51, 52, 53) 54) 71, 74) 98, 99; TOR Mt 70, 205 Tricholoma terreum, 19 Trichophoric cell, 180 Triphragmidium, 219 T. Ulmariae, 196 (Fig. 164), 196) ° Truffles, 8, 138 Tuber, 8, 35, 137 T. puberulum, 137, 138 (Fig. 99) T. rufum, 136 (Fig. 97), 137 (Fig. 98) Tuberaceae, 19, 97, 135 ef seg., 144; biblio- graphy, 138 Tuberales, 6, 8, 97, 100, 135 Tubeuf, K. F. von, 18, 222 Tuburcinia, 186, 187 T. primulicola, 188, 194, 195 Mulasne, UR. and C., 77,78, 102, 107, 136, 137, 150, 166, 167, 168, 170, 187, 195, 196, 197, 222 212 2, 216 (Fig. mat Umbelliferae, 18 Uncinula, 82 U. Aceris, 83 (Fig. 40) U. necator, 81, 83 Uniseriate spores, 36, 37 (Fig. 5) Uredineae, see Uredinales Uredinales, 2, 6, 15, 22, bibliography, 220 Uredinopsts, 204, 219 Uredosorus, 204, 206, 207, 216 Uredospore, 23, 204 Orocystis, 187 U. Anemones, 194 (Fig. 163) U. Fischert, 187 (Fig. 151) U. Violae, 184 Uromyces, 199: 205, 218, 219 U. appendiculatus , 196 (Fig. 164) U. Cunninghamianus, 217 U. Fabae, 199 U. Ficariae, 208 181, 183, 196 ef sgq.; 225 Cromyces (cont.) U. Poae, 200 (Figs. 170, 171), 203 (Fig. 176), 212 (Fig. 188), 214 (Fig. 193) U. Scillarum, 207, 211 U. Scirpi, 212 Ortica parvifolia, 196 Ustilaginaceae, 188 e¢ sgg. Ustilaginales, 5, 6, 15, 16, 183, 184 e¢ sgq. Ustilago, 15, 187, 188 U. antherarum, 184, 186 (Fig. 149), 191 (Fig. 158), 192 (Fig. 159) U. Avenae, 189 U. Carbo, 187 (Fig. 152), 188, 189 (Fig. 153) U. Hordet, 186 (Fig. 150), 189 (Fig. 154) U. levis, 192 (Fig. 160) U. Maydis, 21, 184, 190 (Fig. 156), 191 (Fig. 157), 195 U. Scabtosae, 185 (Fig. 147) U. Tragoponis pratensis, 189, 190 (Fig. 155) U. Treubiz, 184 (Fig. 146) U. Tritict, 189 U. Vaillantti, 191, 195 U. violacea, 21, 184 U. Zeae, 193 Vaccinieae, 124 Vallory, J., 155, 156 Valsa, 165 Valsaceae, 154, 164 Vanda, 17 Varilov, 1., 27 Venturia, 161 Verpa. 129 Verrucose spore, 5 Vicia faba, 13 Wager, H., 31, 33, 64. and Peniston, A., 66 Walled non-motile spore, 4 Ward, H. Marshall, 11, 12, 19, 23, 25, 26, 27, Os) Fis 195s) ZL z ZO Weiss, F. E, 20 Welsford, E. J., 9, 12; 47, 48, 117, 122, 145, 203, ivy PO, QM and Blackman, V. H., see Blackman and Welsford —— and Fraser, El. (@. I5 see) Brasex and. Welsford Werth, E., and Ludwig, K., 192, 195, 208, 221 West, C., 20 Wheat mildew, 23, 79, 210 Willia Saturnus, 65 Wilson, M., 194, 195 Winge, O., 85, 86, 89 Winter, Ge, 505.222 Witch’s-broom, 16, 90, gt Wolf, F. A., 158 Wiolfesmjenl=..t7/3 Wolk, J. P. van der, 61, 62 Wolkia decolorans, 60, 61 ood, fungi on, 7 Wormald, H , 22, 27 Woronin, M., 157, 158, 163 Woronin’s hypha, 142 Vi oronina, 15 Wound parasites, 14 232 INDEX Aylaria Hypoxylon, 167 (Fig. 124) Zodionuyces, 27 X. polymorpha, 14% (Fig. 103), 170 (Figs. 128, Z. vorticellarius, 173 (Fig. 133), 176 (Fig. 138) 120) Zoosporangium, 4, 15 X. Tulasnet, 21 Zoospore, I, 4, 15 Xylariaceae, 154, 165 e¢ sgg.; bibliography, 170 Zopf, W., 156, 158 Zukal, H., 73, 76 Zygomycetes, 5, 8 NEO ot S107} Zygosaccharomyces, 63 (Fig. 24) Yeasts, 2, 7, 11; asd see Saccharomycetaceae Z. Barkeri, 64 ~ ’ Z. Chevalieri, 64 Zaghouania, 220 Zygotaxis .27 Zea Mays, 21, 190 Zymase, 10, 12, 62 PRINTED IN ENGLAND BY J. B. PEACE, M.A. AT THE CAMBRIDGE UNIVERSITY PRESS BINDING SECT. APR 16 1975 PLEASE DO NOT REMOVE CARDS OR SLIPS FROM THIS POCKET UNIVERSITY OF TORONTO LIBRARY ms Gwynne-Vaughan, Helen (Dame) | 603 Fungi, Ascomycetes, | on Ustilaginales, Uredinales Botany 8 SiO 80 61 v0 Ol 6€ 2 WALI SOd JIHS AVE JDNVY G MAIASNMOG LV TL oe pe rar