oe a - Oe ee ae ee oe . A TEXT-BOOK OF MYCOLOGY AND PLANT PATHOLOGY HARSHBERGER iy — sy; ete . | eee PY AT A Te . i= eas dr) is | SGOT AH, Tee x - ie ret ; hie! ate ; Se) th ’ ie as : | re A LAO IOS I SEMOOAOHTAS A TEXT-BOOK ‘OF Par COLOGY.AND PLANT PeebiO LOGY BY JOHN W. HARSHBERGER, PH. D. PROFESSOR OF BOTANY, UNIVERSITY OF PENNSYLVANIA; MEMBER OF THE BOTANICAL SOCIETY OF AMERICA; VICE-PRESIDENT OF THE ECOLOGICAL SOCIETY OF AMERICA, ETC. WITH 271 ILLUSTRATIONS PHILADELPHIA Dob bAKISTONS SON a CO. 1012 WALNUT STREET CopyRIGHT, 1917, BY P. BLAKISTON’s Son & Co. AUG 20 1917 i THE MAPLE-PRESS YORK PA ©c.a470708 L4 Ks PREEACE This book is the outcome of twenty-seven years’ experience, as a teacher of botany, during which fifteen years have been given to a graduate course on the morphology, classification and physiology of the fungi, and five years to a course which combined with this considera- tion a parallel study of the most important cultural and inoculation methods used by the practical bacteriologist and mycologist at the present day. The English and Germans have led in the production of text-books on mycology and pathology; Berkeley, Smith, Cooke and Massee in England, Frank, Sorauer, von Tubeuf and Kiister in Germany. Americans have been behind in this important field, notwithstanding, that American plants harbor some of the most destructive fungi, which, through our careless methods of agriculture and horticulture up to the present, are annually destructive to the extent of millions of dollars. This lack is being rapidly remedied and the appearance of text-books by Duggar, Stevens, Hall and Stevens, Mel T. Cook and general monographs by Erwin T. Smith, and others, augurs well for the future of this line of literary and scientific labor. The bacteriologists have led and mycologists should follow. The following pages represent in a much extended form the lectures and laboratory exercises given by the author before his botanic classes at the University of Pennsylvania, and before public audiences else- where, especially, Farmers’ Institutes with which he has had three years’ experience as a lecturer in Pennsylvania. The arrangement of the text has been suggested by the needs of the classroom and from an acquaintance with similar work in other colleges and universities in America. It is hoped that the book and the suggestions, as to teaching which it contains, will appeal to those responsible for similar courses. The keys are given with the anticipation that they will prove useful to the student and teacher who desire exercises in the classification of the fungi: The illustrations have been chosen with care, and credit is given in all cases for those borrowed from other books and monographs. The author hopes that the book is reasonably free from misleading = ; vi PREFACE statements, and that it will prove useful to the teaching and student body. The exercises, which are given in detailed form are designed to acquaint the student with the methods that are used in the cultural investigation of the bacteria and fungi. It is also designed to introduce the student to the highly important subject of Technical Mycology. The modern demands for investigators trained in technical my- cology aremany. The health bureaus of our large cities need men and women, who can make a study of the milk, water and food supplies. The men, who are engaged in the fermentation industries, frequently demand expert information on the bacterial and fungal organisms, that . are either useful, or harmful, in the fermentation process. The bread baker should have someone to whom questions relative to his, one of the oldest, arts could be referred. The canner also needs such expert advice. The farmer depends upon the fertility of his soil for the growth of crops, and the character of that fertility determines whether his crop shall be a large or a small one. It is conceded on all sides at present that fertility is due not alone to the chemical character of the soil, but also to other conditions which are quite as influential, such as, the physical state, the bacterial and fungous flora and the presence or absence of toxic substances. A study of the mycologic flora of the soil can only be pursued satisfactorily by those who have been: trained in cultural methods. Then too the study of plant diseases and animal diseases rests funda- mentally upon technical mycologic laboratory methods. The alarm- ing increase of plant diseases has attracted a larger and ever growing number of young men into the study of bacteriology and fungology. There seem to be unlimited opportunities for such carefully trained men and women to get profitable employment in health bureaus, manufac- turing plants, agricultural experiment stations, and as plant doctors stationed in our larger towns and cities, ready, as a medical doctor is ready, to give for a monetary consideration expert advice and treatment. Lastly, there are chances for men and women trained in technical mycology to become professors, or teachers, of the subject in our col- leges and agricultural high schools. Such trained specialists can help to increase the crop-producing capacity of our farms by eliminating the prevalent diseases, which reduce seriously the farmers’ profits. Such specialists are conservationists in the truest sense of the term. PREFACE vil The author, with great pleasure, thanks the following persons for suggestive help in the preparation of the text-book: Professor J. C. Arthur read the proof of the chapter on the rust fungi; Prof. D. H. Bergey of the University of Pennsylvania the pages dealing with laboratory methods. Prof. Mel T. Cook and his associates J. C. Helyar and C. A. Schwarze of the New Jersey Agricultural Experiment Station, New Brunswick, read the galley proofs throughout and made valuable suggestions, Dr. J. S. Hepburn read the pages dealing with bio-chemistry. Messrs. H. R. Fulton and Donald Reddick also made valuable suggestions as to the arrangement of the contents of the book, while Prof. L. R. Jones and Dr. C. L. Shear furnished illustrations for reproduction in the text. Prof. A.H. Reginald Buller of the University of Manitoba gave permission to use five illustrations in his book, “Researches on Fungi.’’ The author desires to express his thanks for the uniform courtesy of members of the firm of P. Blakiston’s Son & Co., especially to Mr. C. V. Brownlow, whose unfailing interest has done so much to forward the publication of the work. Je AW. CONTENTS PART 1.0 MYCOLOGY PAGE CHAPTER I.—GENERAL STATEMENT AND CLASSIFICATION. . . . . + «= « I CHAPTER 11— Strum Movrps (MYXomMVCETES), F000. s eee ee OT CHAPTER III.—TuHe BActTEeERIA IN GENERAL. . . . 21 Name; Size; Locomotion; Cell Division and ResrodicnGa SiS SHER Chromogens; Thermogens; Aerobism and Anaerobism. CHAPTER IV.—CLASsIFICATION OF BACTERIA . . . 28 According to Nutrition; Prototrophic Bacteria; Mbtaeopine Baer Paratrophic Bacteria; Systematic Account of the Bacteria; Bibliography. CHAPTER V.— CHARACTERISTICS OF THE TRUE FUNGI ....+...+.- 42 CHAPTER VI.—HistoLocy: AND CHEMISTRY OF FUNGI. . . 52 Histology; Cell Contents; Colors; Physiology; Enzymes; Cipeinextean, & Enzymes in Fungi; Chemotaxis. CHAPTER VII.—GerneraL Puysiotocy oF Funct... ........ 61 Influence of Light; Luminosity; Liberation of Spores. CHAPTER VIII. —Ecotocy OREN Gia anya <2 Se egh eehen pS eect ang: ¢ LOO Saprophytes and Parasites; Sclerotia; Cale: Habitats; Xerophytism; Lichen Fungi. CHAPTER IX.—Fossit Funct AND GEOGRAPHIC DISTRIBUTION . . . 82 Fossil Fungi; Geographic Distribution; Habitats of Lichens; etibeige of Chestnut Blight; Laboulbeniacee; Family Clathracez. Mit ink -—PHVLOCENY OF FUNGI...) 7%... ys oes 89 CHAPTER XI.—Movutp FuncI. . . . 92 Order Zygomycetales; Sexual eardiedon: Sau an. Sener bee mentation; Key to Families of the Order Zygomycetales; Mucoraceex; Mortierellacee; Choanephorace; Chetocladiacee; Piptocephalidacee; Entomophthoracee; Bibliography. CHAPTER XII.—Oospore-PropucING ALGAL FUNGI . . . Re ioy, Sexual Reproduction; Haploid and Diploid State; Key to Barnes: iano blepharidacee; Saprolegniacee; Peronosporacee, Generic Key to Family Peronosporacee, aibs X CONTENTS PAGE CHAPTER XIII.—Oomycetates (ContTINUED) . . . sien: Chytridiacee; Ancyclistacee; Bibliography. CHAPTER XIV.—HiIcHER Funct . 120 Ascomycetales; Sexuality, Claussen and Harper; Life Cycle; Bibliography. CHAPTER XV.—Sac Funci In ParTIcuLAR (YEASTS, ETC.) a: Endomycetacee, Exoascacee; Saccharomycetacee; Yeasts, cells and fer- mentation, etc.; Systematic Position. CHAPTER XVI.—Sac Funer (Continuep). . le 2 ne Gymnoascacee; Aspergillacee; Elaphomycetacex; Terfeziacee; Tuberacexr (Truffles); Myriangiacee. CHAPTER XVII.—Mi.LpEews AnD RELATED Funct . 2: ieee eee Erysiphacee (Mildews); Perisporiacee; Microthyriacex; Hypocreacee; Dothideacee; Sordariacee; Chetomiacee; Spheriaceee; Valsacee; Melo- grammatacee; Xylariacee; Hysteriacee; Phacidiacex; Pyronemaceex; Ascobolacee; Pezizacee; Helotiacee; Mollisiacee; Geoglossaceze; Helvel- lacee; Cyttariacee; Rhizinacee; Phylogeny of Ascomycetales; General Bibliography. CHAPTER XVIII.—Basip1a-BeartnGc Funcr (Smuts) . oth eae Key to Suborders; Ustilaginacee (Smuts); Bibliography of Smuts. CHAPTER XIX.—Rust Func1 . 2 yk Me chs, Stews General Structure; Forms; Life Cycles; Cytology; Phylogeny; Endophyl- lacee; Coleosporiacee; Pucciniacee; Bibliography of Rusts; Auriculariacee ; Tremellacee (Trembling Fungi). CHAPTER XX.—FLEsHyY AND Woopy FuncI .1 Wicket ee Cytology; Dacryomycetacee; Exobasidiacee; Hypochnacee; Thele- phoracee; Clavariacee; Hydnacee; Polyporacee; Manuals. CHAPTER XXI.—MusHrooms AND TOADSTOOLS . oo: lau Agaricacee; Development of Fruit Bodies; Cultivation of Mushrooms; Chemistry and Toxicology of Mushrooms; Gasteromycetes; Hymeno- gastracee; Tylostomacee; Lycoperdacee; Nidulariacex; Key to; Sclero- dermacee; Sphexrobolacee; Phallomycetes; Development of Carrion Fungi; Clathracee; Phallacee; Bibliography of Eubasidii. CHAPTER XXII.—Funer Imperrecti (DEUTEROMYCETES) . ee General Characters; Systematic Position; Sphzropsidales; Melanconiales; Hyphomycetales. PART II. GENERAL PLANT PATHOLOGY CHAPTER XXIII.—GENERAL CONSIDERATION OF PLANT DISEASES . Etiology; Predisposing Causes; Determining Causes; Physical Character of Soil; Climatic and Meteorologic Factors, Effect of Smoke, etc.; Trauma- tism; Animate Agents of Disease; Insects. - Lar 143 154 187 218 231 258 ea CONTENTS xi PAGE CHAPTER XXIV.—P tants As DIsEASE PRoDUCERS, EPIPHYTOTISM, PROPHY- VAIS ese. 208 Vegetal Agents of Wisease’ Parasitic Blowerte Plants; iagous Opens ats as the Cause of Disease; Mechanic Injuries; Injuries Due to Meteorologic Causes; Infection; Incubation; Duration of Disease; Dissemination of Fungi; Epiphytotisms (Epidemics); Prophylaxis. CHAPTER XXV.—PRACTICAL TREE SURGERY .. . 319 Preventive Measures; Character of Work; Cavity shpese mene ives aa Placing the Cement; Metal-covered Cavities; Guying. CHAPTER XXVI.—INTERNAL CAUSES OF DISEASE. ... 326 Enzymes; Panaschiering; Calico; Nutritive Disturbances; Natatione: vet formations and Monstrosities; Graft Hybrids; Chimeras. CHAPTER XXVII.—CLASSIFICATION OF ABNORMALITIES. . . . JiR AD gor CHAPTER XXVIII.—Symptoms or DISEASE (Soupsemimoroceir tte 341 Symptoms of Disease; Discolorations; Shot-holes; Wilting; Nears: Dwarfing; Hypertrophy; Replacement; Mummification; Alteration of Position; Destruction of Organs; Excrescences and Malformations; Exudations; Rotting; Bibliography of Diseases in General. CRAP ERSXeXS Xt ——PATHOLOGIC “PLANT ANATOMY: 5254 2°...) 92 38 354 Restitution; Hypoplasia; Metaplasia. CHAPTER XXX.—PatHotocic Prant ANATOMY (CONTINUED). 364 Hypertrophy; Excrescences; Intumescences; Callous Hay pererephie Ty- loses; Gall Hypertrophies; Hyperplasia; Homooplasia; Heteroplasia; Callus; Conditions of Callous Formation; Wound Wood; Wound Cork. CHAPTER XXI.—GalLtis. ... 384 Kinds of Galls; Cataplasms; istoloxy ise Cutapkacme: Fistoleg gy Abe Galls; Cecidial Tissue Forms; Bibliography of Galls. CHAPTER XXXII.—MeEcuHanic DEVELOPMENT OF PATHOLOGIC TISSUES... 463 General Consideration; Bibliography of Developmental Mechanice, Sug- gestions to Teachers and Students. PART III. SPECIAL PLANT PATHOLOGY CHAPTER XXXIII.—Spectric DISEASES OF PLANTS. .. . All General Statement; Principal Publications; List of Common aed ise Diseases of Economic Plants in the United States and Canada Arranged according to Host Plants. CHAPTER XXXIV.—DETAILED ACCOUNT OF SPECIFIC DISEASES OF PLANTS. 475 Alfalfa to Grape. CHAPTER XXXV.—DETAILED AccouNT oF SPEcIFIC PLANT DISEASES (CONTINUED) iy te enciseiny Ga ie/eertr es AURIS) LOE REET ala deed Ree. te SY Hemlock to Wheat. xil CONTENTS CHAPTER XXXVI.—Non-PARASITIC, OR PHYSIOLOGIC PLANT DISEASES... CHAPTER XXXVII.—LaBorAToRY AND TEACHING METHODS . Classification; Stag-head; Root Asphyxiation; Desiccation; Water-logging; (Edema; Frost Necrosis; Apple Fruit Spots; Water-core of Apple; Die- back, or Exanthema; Mottle-leaf; Curly-top of Sugar Beets; Peach Yel- lows; Tip-burn of Potato; Leaf-casting; Curly-dwarf of Potato; Bean Mosaic; Mosaic of Tobacco; Bibliography. PART IV. LABORATORY EXERCISES TN Siete CULTURAL STUDY OF AUG Introductory Remarks; Lesson 1, Micrometry; Lesson 2, Plugging Test- tubes, etc.; Lesson 3, Microscopic Study of Culture Material; Stains; Lesson 4, Taiid Nutrient Solutions; Lesson 5, Potatoes as Medium; Lesson 6, Solid Vegetable Substances; Lesson 7, Plaht Juices; Lesson 8, Milk, Beer- wort; Lesson 9, Bouillon; Lesson 10, Eggs; Lesson 11, Nutrient Gelatin; Lesson 12, Agar-Agar; Lesson 13, Various Nutrient Agars; Lesson 14, General Directions for Making Plant Agars; Lesson 15, Potato Juice Agar; Lesson 16, Starch Agar; Lesson 17, Culture Media for Nitric Organisms; Lesson 18, Standardization of Culture Media; Lesson 19, Germination Studies; Lesson 20, Counting of Yeasts and Bacteria; Lesson 21, Cultiva- tion of Yeasts on Gypsum Blocks, Method of Pouring Plates, Streak Method; Lesson 22, Isolation of Fungi; Lesson 23, Water Analysis; Lesson 24, Methods of Identification; Lesson 25, Plate Counter; Lesson 26, Sys- tematic Bacteriology; Lesson 27; Scheme for the Study of Bacteria; Lesson 28, Detailed Study of Bacteria; Lesson 29, Directions for the Study of Pathogenic Fungi. CHAPTER XXXVIII.—Laporatory AND TEACHING a (CONTINUED) Lesson 30, Inoculation Experiments; Lesson 31, ; Lesson 32, Do:; Lesson 33, Do.; Lesson 34, Do.; Lesson 35, cee with Artificial Wounding of Plants: Lesson 36, Gas Injuries; Lesson 37, Enzyme Diseases; Lesson 38, Study of Mistletoe; Lesson 39, Wire Worms in Plants; Lesson 4o, Relation of Light to Pathogenic Conditions; Lesson 41, Withering, or Wilt- ing of Plants; Lesson 42, Methods of Sectioning, Celloidin, Paraffin; Lesson 43, Freezing and Cutting of Material; Lesson 44, Use of Drawing and Projection Apparatus, Drawing WMietneds: Lesson 45, Suggestions to Teachers and Students; Lesson 46, Content of Field Trips and Excursions. APPENDIX I.—FunciIcwEs. . Bordeaux Mixture, etc. APPENDIX II.—Spray CALENDAR : F APPENDIX III.—AnriseEpsis AND DISENRECTION : Preservation of Woods. PAGE 564 SI5or 643 . 669 . 680 . 692 CONTENTS xlli PAGE APPENDIX IV.—CuLturE or MusHRooMsS ... . . 693 APPENDIX V.—Synopsis or FAMILIES AND ae Saat eae OF vee: GASTRATES:: 2... ca) 008 APPENDIX VI. =Kevr FOR THE ADene nue anvant OF Specs OF ‘Mucor so 6 (os APPENDIX VII.—Kerys ror THE DETERMINATION OF SPECIES OF ASPER- GILLUS AND PENICILLIUM ... . Sesh eee LO APPENDIX VIII.—Kevys To THE Goan OF THE easier ene a a Bae ay Ot APPENDIX IX.—CoLLECTION AND PRESERVATION OF FLESHY FUNGI . . . 726 APPENDIX X.—List oF Krys TO FLESHY FUNGI AND SELECTED KEYS OF FLESHY FUNGI... . rn cat ke bine Ree eens Coke. 720 APPENDIX XI.—Key To (eee Se aE es TR A Lr cin Wipe, et EI LN} EN UG Sansa cei loka hdc! gS lay la, gue" one Rae wae ely Gg px : SERA MY -: 74h ; RT ara ee tis by . i Leh ee? - For FSTt 9.) ees SP er haabcae ey oR maha, io ae £geh - Boe CF < Pa owe Y, ee 4 os A ee MEO Sone Breet eat Konia MERTEN 237 ey ap 1 mean 3H SRPISNr. qe weir A eeereree tt vie a Stata eax. Uys: le sibs TANT at. Sie iz a eee Aorta See oy Be) VUE A ee ARO Rate sri) es Wed ere EPS Tee Portes i Eee eer ae + 7 tee ~~ bay a Re ip RIESE t a Cae ie od *. i of ¥ "9 ; x Sets E by = = - aA: , ea ty = Pe Lae i 2 ec Bk. Ri hs ee ; Roo WT sris-et é ea hs? lees Giiaet +! Ee aielog a Sa tat: sea, eee ce, eee So, Sn eae i oy : ‘ ye he eae ae benes AN {ea 52 arab Va bigs danse (as iis i ste Be: mi + 3 : eh ti at eee = es pS SARK at Vibele a eer 4 ean | aia tc zm ae se PART | MYCOLOGY CHAPTER I GENERAL STATEMENT AND CLASSIFICATION The lower plant organisms which concern the mycologist, or the student of the fungi, may be considered in a general sense, or in a narrow way. A general definition would include all those thallo- phytes, or lower cellular plants (lacking archegonia), which are destitute of chlorophyll and in its absence become dependent, with the exception of the prototrophic bacteria, upon extraneous supplies of organic food, either living or dead. This broad definition compels the mycologist to study the slime moulds, the bacteria and the true fungi, both as to their morphology and their physiology. He finds on such study, that broadly speaking, there are similarities of structure and function in both groups of dependent plants, in fact, he finds that ‘the function of these plants is connected with cell organization and structure and vice versa. With this clearly in view, the mycologist finds that he has to deal with three distinct classes of chlorophylless plants, namely: Crass Myxomycetes (slime moulds). CLASS SCHIZOMYCETES (bacteria). Criass Eumycetes (true fungi). The classification of these colorless (chlorophylless) lower plants has been elaborated in recent years with considerable detail by various authors, so that the broad fundamental facts both of taxonomy and phylogeny are known fairly well, but much remains to be done along the classificatory lines, especially, since the life histories of many of the bacteria and fungi are incompletely known. It may be many years before a generally acceptable nomenclature and classifi- cation wili be an accomplished fact. The choice of a classification by any worker in mycology depends largely on his training and bias and on his detailed study of the various groups. No two men would entirely agree as to which was the best sequence to adopt in a system- atic treatment of the different forms. The classification adopted in this I 2 MYCOLOGY treatise is based on that of Engler and Gilg, as published in the seventh illustrated edition of “Syllabus der Pflanzenfamilien,” Berlin, 1912, and on that of Wettstein in his ‘Handbuch der Systematischen Botanik,” Leipzig and Vienna, to11. Where consistent, the classificatory sys- tems of these two books are harmonized and any departures which the student will find from the taxonomic arrangements of Engler and Wettstein have been made to simplify them by the omission of cer- tain group names, or to bring the two systems into line with the facts as at present known. The author has not hesitated to make changes, where from his experience as a teacher, he has found it best to make such alterations, especially where, for example, Wettstein uses Ordnung and Engler Reihe for the same classificatory group, and where in American usage order and family are used. Then, too, the author has found it convenient to replace the name of a family, or order, as given by Engler for one used by Wettstein, or some other author, where such replacement is recommended by American usage, or where etymolog- ically the name is more suggestive of the character of the group, and, therefore, best for the use of students who do not expect to follow out the intricacies of any system of classification. As the statements and views of Engler and Wettstein are generally dependable and as their classification is founded on long experience, as systematic botanists, it will be found that with respect to the larger subdivisions of the fungi their classifications are remarkably harmonious. The attempt has been made in the pages that follow to simplify for student use the facts of classificatory importance and while the groups are ar- ranged in lineal sequence, it should be explained that true relationship is expressed better by a family tree with main trunk, larger and smaller branches. It will be noted that the arrangement of the families, as given in the two systematic works above mentioned, are sometimes reversed. The simple groups are given first place, followed by the more complex. CLASS I. MYXOMYCETES. ORDER I. ACRASIALES. Family r. Guttulinacee. Family 2. Dictyosteliacee. ORDER II. PHYTOMYXALES. Family rt. Plasmodiophoracee. \ GENERAL STATEMENT AND CLASSIFICATION 3 ORDER III. MYXOGASTRALES. SUBORDER. EXOSPOREZ. Family 1. Ceratiomyxacee. SUBORDER. ENDOSPORES. Family 2. Physaracee. Family 3. Didymiacez. Family 4. Stemonitacee. Family 5. Brefeldiacee. Family 6. Cribrariacez. Family 7. Liceacee. Family 8. Tubiferacee. Family 9. Reticulariacee. Family to. Trichiacee. CLASS II. SCHIZOMYCETES. ORDER I. EUBACTERIALES. Family 1. Coccacee. Family 2. Bacteriacee. Family 3. Spirillacee. Family 4. Phycobacteriacee (Chlamydobacteriacez). Family 5. Thiobacteriacee (Beggiatoacez). Family 6. Actinomycetaceze (position doubtful). ORDER II. MYXOBACTERIALES. Family 1. Myxobacteriacee. CLASS III. EUMYCETES. SUBCLASS. PHYCOMYCETES. ORDER I. ZYGOMYCETALES. Family 1. Mucoracee. Family 2. Mortierellacee. Family 3. Choanephoracee. Family 4. Chetocladiacee. Family 5. Piptocephalidacee. Family 6. Entomophthoracee. MYCOLOGY ORDER II. OOMYCETALES. Family rt. Monoblepharidacez. Family 2. Saprolegniacee. Family 3. Peronosporacee. Family 4. Chytridiacez. Family 5. Ancyclistacee. SUBCLASS. MYCOMYCETES. ORDER III. ASCOMYCETALES. SUBORDER A. PROTOASCIINE. Family 1. Endomycetacee. Family 2. Exoascacee. SUBORDER B. SACCHAROMYCETIINE & Family 1. Saccharomycetacee. SUBORDER C. PLECTASCIINE®. Family 1. Gymnoascacee. Family 2. Aspergillacee. Family 3. Elaphomycetacee. Family 4. Terfeziacee. Family 5. Tuberacee. SUBORDER D. PERISPORIINEA. Family 1. Erysiphacee. Family 2. Perisporiacee. Family 3. Microthyriacee. SUBORDER E. PYRENOMYCETIINE®. Family 1. Hypocreacee. Family 2. Dothideacee. Family 3. Sordariacee. Family 4. Chetomiacez. Family 5. Spheriacee. Family 6. Valsacee. Family 7. Melogrammatacez. Family 8. Xylariacee. GENERAL STATEMENT AND CLASSIFICATION SUBORDER F, DISCOMYCETIINE®. Family 1. Hysteriacee. Family 2. Phacidiacee. Family 3. Pyronemacee. Family 4. Ascobolacee. Family 5. Pezizacee. Family 6. Helotiacee. Family 7. Mollisiacee. Family 8. Celidiacez. Family 9. Patellariacee. Family ro. Cenangiacee. SUBORDER G. HELVELLIINEZ. Family 1. Geoglossacee. Family 2. Helvellacee. Family 3. Cyttariacee. Family 4. Rhizinacee. SUBORDER H. LABOULBENIINE. Family 1. Peyritschiellacez. Family 2. Laboulbeniacee. Family 3. Zodiomycetacee. ORDER IV. BASIDIOMYCETALES. SUBORDER. HEMIBASIDIINE®. Family 1. Ustilaginacee. Family 2. Tilletiacee. SUBORDER. UREDINE&. (Usually Order UrepINALEs). Family 1. Endophyllacee. Family 2. Melamsporacee. Family 3. Pucciniacee. Family 4. Coleosporacee. SUBORDER. AURICULARINZ. Family 1. Auriculariacee. Family 2. Pilacracee. SUBORDER. TREMELLIN. Family 1. Tremellacee. 6 MYCOLOGY SUBORDER. EUBASIDIINE. A. HYMENOMYCETES. Family 1. Dacryomycetacee. Family 2. Exobasidiacee. Family 3. Hypochnacee. Family 4. Thelephoracee. Family 5. Clavariacee. Family 6. Hydnacee. Family 7. Polyporacee. Family 8. Agaricacee. B. GASTEROMYCETES. Family 1. Hymenogastracez Family 2. Tylostomacee. Family 3. Lycoperdacee. Family 4. Nidulariacee. Family 5. Sclerodermacee. Family 6. Spherobolacez. C. PHALLOMYCETES. Family 1. Clathracee. Family 2. Phallacee. Funcr Imperrecti (Deuteromycetes). ORDER I. SPHAZROPSIDALES, with 4 families. ORDER II. MELANCONIALES, with 1 family. ORDER III. HYPHOMYCETALES, with 4 families. The above classification has been given in outline with the object of presenting to students the information which is requested frequently of the professor in the class room. A detailed presentation of the spe- cial morphology, histology, embryology and taxonomy of each group will be given in the pages which follow, omitting matters concerning pathology and practice. A separate section of this treatise will be devoted to the consideration of fungous diseases of plants and their treatment. CHAPTER Ii SLIME MOULDS (MYXOMYCETES) CLASS I. MYXOMYCETES Considerable attention has been given in recent years to the slime moulds on account of their biologic interest, taxonomic relationship and disease-producing forms. As organisms, they have been bandied about. They have been claimed by zoologists and botanists alike, for incertain stages of their life cycle they strongly suggest the protozoa, such as the amoeba. Perhaps on account of this uncertainty one would be justified in placing the slime moulds in the class Protista of Haeckel, which group was intended to include all such primitive organisms which naturalists have been unable to put satisfactorily either in the animal, or the vegetable kingdoms, but which partake of the nature of both the animal and the plant phyla. Hence we would have as a tentative arrangement PROTISTA Pasniye ve > PROTOZOA PROTOPHYTA where the Protista represent the primitive stock of organisms which have given rise to simple animals on the one hand, or primitive plants on the other. Fries and some of his predecessors considered that the slime moulds were puffballs (Gasteromycetes) and the expression of this view is suggested in the name MyxoGAstres given them by Fries in 1833. Wallroth in 1836 viewing them as related to the fungi termed them MyxomycetTEs. De Bary, the German botanist, in 1858, impressed by their closer relationship with the animal world, called them Myce- TozoA. Zopf in 1885 describes them as Die Pilzthiere and Rostafinski, a pupil of De Bary, working under his supervision in an elaboration of a monograph of these organisms, calls them Mycretozoa. We, there- fore, are limited by strict priority to adopt the name MyxoGastREs for them; but there are valid reasons why the name MyxomycETES 7 8 MYCOLOGY should be used. One of the strongest arguments is that if we consider them as plants they belong to the phylum of the fungi and hence this name MyxomYceTEs aligns itself with ScuizomycETES and EUMYCETES generally adopted for the other groups of fungi. It conduces to clarity and simplification of classification to adopt the name of Wallroth for the class of organisms incapable of an independent existence, being destitute of chlorophyll and mainly saprophytic. The older name is retained, however, as the name of the third order of MyxomycETEs, hence there should be little criticism of the view taken above. The MyxomyceTEs (Mycetozoa, Schleimpilze, Pilztiere, Sime Moulds) are chlorophylless organisms. ‘Their vegetative condition is known as a plasmodium which is a naked streaming mass of protoplasm. Repro- duction is by means of spores produced as exospores, or endospores, the latter in sporangia, ethalia, or plasmodiocarps. The spores give rise to amceboid cells or flagellate swarmers which unite later to form the plasmodium, or develop directly into the plasmodium. ORDER I. ACRASIALES.—The members of this order live on the excrements of animals and on the decaying parts of plants. They commence their development with the escape of an amoeboid body from the walls of the spore and then move about by creeping move- ments, never assuming cilia for locomotion. The amceboid cells pile up on one another without coalescing to form what has been called an aggregate plasmodium, and they remain distinct, and artificially sepa- rable, though closely packed together until the fructification forms, when they rise above the substratum and form bodies of definite shape. Every one, or the majority of these definitely arranged ame- boid bodies, becomes a spore covered by a delicate membrane and of an average size of 5 to1oyw. These heaps of spores resemble the sporangia of the true slime moulds, but there is no distinct sporangial wall, the spores being held together by a structureless enveloping substance. The plants of this group are saprophytes. Guitulina rosea lives on decaying wood in Europe. Dictyostelium mucoroides is frequent on old dung, while Acrasis granulata is found on old yeast cakes. Poly- sphondylium violaceum occurs in southern Europe on manure. ORDER I. PHYTOMYXALES.—The slime moulds of this order are parasites which live in the cells of higher plants. The plasmodium is limited by the cell walls of the host plants, and has its origin in amoeboid cells which enter and infest the host cells, resulting in a SLIME MOULDS (MYXOMYCETES) 9 stimulation of the host to form gall-like swellings. The whole plas- modium is later transformed by division into a greater or less number of parts, which become surrounded by membranes to form spores. The spores are free in the cells of Plasmodiophora, while in Sorosphera and in Tetramyxa they are clumped, and surrounded by a delicate membrane. The order includes a single family: FAMILY 1. PLASMODIOPHORACEZ.—The characters of this family are coincident with those of the class as given above. The family includes four genera distinguished as follows: A. Spores distinct from each other, irregularly aggregated and filling the host cells. (a) Spores regular in shape, spheric. (1) Plasmodiophora. (b) Spores irregularly shaped, rod-like, or angular. (2) Phytomyxa. B. Spores united into clumps inclosed by a delicate membrane. (a) Spores united in groups of four each. (3) Tetramyxa. (b) Spores in greater number, united into hollow spheres. (4) Soros phera. The genus Plasmodiophora comprises possibly three species found in Europe and America. They are parasites in the parenchyma cells of the cortex of the roots of the higher plants, where they produce gall-like swellings. The plasmodium fills some of the living cells of the host. The spores formed subsequently are spheric and lie free within the host cells. The best known species is P. brassice which is the cause of a serious disease known as club foot, or finger and toes (Fig. 1). The symptoms of the disease, the relationship of host and parasite, will be described in a subsequent section of this book. Two other species have been described, viz., P. ali in the roots of the alder; and P. eleagni in the roots of Eleagnus, the silverberry. Considerable more study will have to be made of the organisms in the roots of the alder and silverberry before we can definitely place the causal organ- isms. Tentatively, we may adopt the generally accepted view of the systematic relationship of the two responsible organisms until later investigation either proves or disproves the nature of the parasites attacking Alnus and Eleagnus. The genus Phytomyxa is represented by two species which live as parasites in the roots of living plants and cause tuber-like enlargements. The plasmodia fills the host cells, and later, the irregularly shaped Io MYCOLOGY sgwes Six eet a> ADS SH Fic. 1.—Club-root of cabbage, Plasmodiophora brassice. 1, Turnip with club- root; 2, section of cabbage root with parenchyma cells filled with slime mould; 3, isolated parenchyma cell, (v) vacuole; (t) oil-drops in plasmodium, (p) plasmodium; 4, lower cell with plasmodium, upper cell with spores developing; 5, parenchyma cell with ripe spores; 6, isolated ripe spores; 7, germinating spores; 8, myxamoeba. (Figs. 2-8, after Woronin in Sorauer, Handbuch der Pflanzenkrankheiten, 1886, p. 72.) SLIME MOULDS (MYXOMYCETES) 11 spores fill the infested host cells. Two species have been described. The nature of Ph. leguminosarum is doubtful, as it may have been confused with one of the stages of the nodule-producing bacteria, which are found in the roots of leguminous plants. The parasitic slime mould, Tetramyxa, occurs as one described species Tetramyxa parasitica, which lives in the stems and flower stalks of water plants, as Ruppia rostellata, where it causes tubercles 0.5 to I mm. in diameter. Each host cell contains numerous colorless spores united into tetrads. Sorosphera is represented in Germany by S. veronice found in the stems and petioles of Veronica hederifolia, V. triphylla and V. chame- drys. The cells of the galls are swollen and filled with numerous spheric or ellipsoidal brown balls, 15 to 22 w in diameter, formed of a single layer of spores united into a hollow sphere and covered externally by their pellicle. ORDER III. MYXOGASTRALES. Loris order includes the true slime moulds which are non-parasitic, but live on decaying organic material, such as old logs, leaf mould in the forest, compost heaps, spent tan bark and other organic débris in the fields, woods, and along the roadsides. One form grows over the grass of lawns and smothers the grass with its plasmodium and later by its sporangia and spores. The plasmodium is a naked mass of protoplasm usually of a reticulate structure and multinucleate. It arises by the union of the myxameeba which are developed from the flagellate myxomonads by the loss of the vibratile flagella. Such a plasmodium is known as a fusion plasmodium.! It usually assumes a reticulate, or net-like, structure and currents of protoplasm are seen flowing along the strands of greater or less thickness of which the plasmodium is composed. The central portion of each current is denser and moves more rapidly than the marginal clearer protoplasm. Perhaps we are justified in stating that the outer protoplasm is the ectoplasm and the inner granular cytoplasm containing food substances and other included substances is the endoplasm. For some time the plasmodium may flow in a given direction and later it may reverse its course, moving in an entirely opposite direction. The color of the plasmodium differs in different species, as the following table will show. White or yellow seem to be the more usual colors. & 1%n Labyrinthula Cienkowskii parasitic in Vaucheria the plasmodium is filamen- ous. ; 1 MYCOLOGY V ellOW;, 2s hyhoae Romeo sale aan oo eee Fuligo septica. Oran’ Ci i035. Ne Ee ee ae Trichia scabra. Wilhite: seers: «parce NER aa ee = Physarum ellipsoideum. ead=coloredengrmes ara metric Cribraria argillacea. Bikey, eater cin ee ae Ts ees a Enteridium splendens. Ruby=red tise cer eiein tie ers Hemitrichia vesparum. 1ST Ta ae ee oes wt ae Ree hed on ee ae Tubifera ferruginea. Sarl 6 trent ire eee ss Arye ee Cribraria purpurea. BROW eyn eae ie eit Poa ke cs Tubifera Cas paryt. Wil heen seca New ee ses os 8 woe Cribraria violacea. The movement of the plasmodium is associated with the incorpora- tion of food. The yellow plasmodium of Badhamia utricularis has been most carefully studied in its relation to a food supply. It can be cultivated on such woody fungi as Stereum hirsutum, over which it extends, devouring by enzyme action the more delicate hyphe. Thus nourished, it will spread over the moist filter paper inside of the covering bell jar until I have seen the plasmodium hanging down like stalactites from the inner top of the bell jar. Such a captive plasmodium has been fed by the writer pieces of mushroom Agaricus campestris. Shaggymane, Coprinus comatus and beefsteak have been placed on the surface of the protoplasm and in a few hours these substances have been found in advanced stages of digestion. Cheese is reluctantly invaded and is more refractory. The plas- modium is responsive to changes in the moisture surroundings. It moves toward a more abundant water supply. It is hydrotropic. It moves against a current of water and is, therefore, rheotropic. When highly illuminated, the plasmodium moves away from the lighted surface. It is negatively heliotropic. If there is a sudden change in the watery environment, the plasmodium will become massed into a cake-like lump in which form it remains as a sclerotium, macrocyst, or phlebomorph, if the substratum loses its water supply. In the sclerotial condition, the writer has kept a plasmodium for nine months on a plate of glass placed inside of a laboratory case in an absolutely dry condition. It was started into activity at the end of this period of rest on restoring free water to it again, and by feeding it mushrooms, it was kept in its restored activity for several weeks beneath a bell jar. The plasmodial stage may be pro- longed for an indefinite period, if the environmental conditions of temperature, light, moisture and food, are favorable. The writer has SLIME MOULDS (MYXOMYCETES) £3 kept a plasmodium in a streaming condition for over a month be- neath a bell jar. Physarum psittacinum, which inhabits the rotten stumps of old trees, appears to pass a year as a plasmodium. The early stages in the formation of the sporangium have been de- scribed in Comatricha obtusata. When the fruiting period is reached, the watery-white plasmodium issues from the wood crannies and spreads over an area perhaps half an inch across. The plasmodium is seen to concentrate in thirty or forty centers and in an hour or two each center has by rhythmic pulsation of the protoplasm risen into a pear- shaped body with a slender base and an enlarged upper portion. The black hair-like stalk has grown to its full length in six hours and on its summit is borne the young sporangium, which is a white viscid globule of protoplasm. A pink flush now begins to appear in the sporangium. The included nuclei are like those of the plasmodium at first, but later as spore formation proceeds they divide mitotically. The sporangia of the different slime moulds take various forms which will be described in general in the systematic generic keys which follow. They may be either symmetric or irregular in shape, sessile or stalked. The irregular sessile forms, which simulate the net-like appearance of the streaming protoplasm, are called plasmodiocarps. When the fruit body is flat and cake-like with separating walls imper- fectly developed it forms an @thalium. The protoplasm which is left on the substratum and dries down as a film-like residuum is known as the hypothallus (Figs. 2 and 3). The changes which take place in the formation of spores and capillitium have been minutely studied in a number of slime moulds. We owe much to R. A. Harper, E. W. Olive and B. O. Dodge in America and to E. Jahn in Germany for our knowledge of these processes. The process in Didymium melanospermum, according to Harper,! is as follows: The spore plasm condenses so that it is finely granular in the peripheral region and central region near the columella and foamy vacuolar in the middle zone. The capillitium is already formed before the condensation of the protoplasm has been accomplished. It con- sists of smooth threads which pass radially outward from the central dome-shaped columellar cavity to the sporangial wall. The threads of the capillitium are attached at their ends. The protoplasm is in contact with these threads and at this stage the nuclei are scattered 1 Harper, R. A.: Amer. Journ. Bot., i: 127-144, March, 1914. 14 MYCOLOGY a rather uniformly through the spore plasm and are of unequal size. Vacuoles are formed in a still further condensation of the sporangial protoplasm and each of these apparent vacuoles is pierced by a capilli- tial thread which runs through its central] axis. Droplets of water are formed along the capillitial thread as a still further evidence of water extrusion. Cleavage planes now appear at the periphery of the mass of sporangial protoplasm and progress inwardly toward the center. The process of cleavage parallels the extrusion of water and the for- mation of the blocks of protoplasm by these cleavage lines is assisted Fic. 2.—A, B, Comatricha nigra. A, Sporangium, natural size; B, capillitium, 20/1; C, E, Stemonitis fusca; C, sporangium, natural size; D and E, capillitia, 5/1, 20/1; F, H, Enerthema papillatum, F, unripe; G, mature sporangium, 10/1; H, capil- litium, 20/1. (C, D, after nature. A, F,G, H, after Rostafinski; B, E, after de Bary in Die natiirlichen Pflanzenfamilien I. t, p. 26.) by the presence of the vacuoles. The splitting up of the irregular blocks of protoplasm, which have the nuclei irregularly distributed through them, proceeds until the protoplasmic blocks are binucleated, and before this the nuclei are seen in various stages of division which proceeds irregularly in Didymium, while in Fuligo the division of the nuclei is simultaneous in a particular spore sack. The plasma membranes of the capillitial openings are the source of cleavage furrows to even a greater degree than the original surface plasma membrane of the spore sack as a whole. In Fuligo in the final stages of spore formation the spore plasm is condensed about the nuclei, but in Didymium, the ultimate SLIME MOULDS (MYXOMYCETES) 15 result of the progressive cleavage in furrowing is the formation of uninu- cleated rounded spores. They lie packed between the capillitial threads. Most genera of slime moulds have a capillitium (Figs. 2 and 3) consisting of a system of threads, and as we have seen, it appears be- fore the spores are formed. When the capillitium extends from the base of the sporangium, it is associated with a columella (Fig. 2). It differs widely in the different genera of the groups. In some genera, as Trichia and Arcyria, the capillitium consists of free threads, or elaters. In those genera in which calcium carbonate is present in the sporangia, it is found in the capillitium usually when several threads meet forming then the so-called lime knots. In Dictydium, purplish-red granules are imbedded in the threads of the false capillitium and are known as dictydin granules. The formation of the capillitium in certain myxomycetes has been investigated by Harper and Dodge.’ They find that the capillitium is formed by the deposit of materials in the vacuoles from which the capillitial thread is formed and that radiating threads run out from the larger granules which are deposited by the process of intraprotoplasmic secretion. These radiating fibrils sug- gest rather strongly that they are cytoplasmic streams which are bringing materials for the formation of the capillitial wall and its thick- enings which are laid down sometimes as spirals, suggesting that the process is comparable to the ordinary processes of cell-wall formation, but along internal plasma membranes, rather than external. The relation of the fibrils to the capillitial granules is best seen where a capillitial vacuole runs longitudinally. Strasburger’s earlier observa- tions are confirmed by the recent work on capillitial formation, when he described the capillitium of Trichia fallax as originating in vacuolar spaces in the cytoplasm which elongate and take on the tubular form of young capillitial threads, while the formation of the wall and spiral thickenings are due to the deposition of granules as intraprotoplasmic secretions consisting of microsomes of the membranogenous type. Where the capillitial threads are solid they may be called stereone- mata; where hollow, ccelonemata. The spores are discharged from the sporangia, and if they find a suitable medium in which to grow, such as free water, they give rise to swarm cells, as amoeboid bodies, or myxamcebx. These soon acquire a 1 Annals of Botany, xxviii: 1-18, January, ror4. 16 MYCOLOGY flagellum at the anterior end and creep in a linear form with the flagellum extended in advance, or swim about in the water with a dancing move- ment occasioned by the lashing of the flagellum. They have a single nucleus and a contractile vacuole. To a large extent they feed on bacteria which are swallowed by pseudopodia which project from the posterior end of the cell. The swarm cells increase rapidly by biparti- tion. When this takes place, the flagellum is first withdrawn and the main cell assumes a globular form; it then elongates and a constriction occurs at right angles to the long axis. The nucleus divides by karyo- kinesis and in the course of a few minutes the halves of the nuclear plate separate and retreat to the opposite ends of the constricted cell which now divides into two, each new cell acquiring a flagellum. Sometimes the swarm cells become encysted to form the so-called microcysts, or zoocysts. The spores of Ceratiomyxa, which are borne on the outside of column-like sporophores, are white in color. The surface of the sporophore is divided into lozenge-shaped areas each with a projecting stalk bearing a single spore. The nucleus of these spores, according to Jahn, twice divide by karyokinesis, and finally, when the spore germinates, eight amceboid bodies are liberated, each of which develops a flagellum and the cluster swims away by the lashing of the flagella. Finally, these cells separate. All other myxomycetes have spores which in germination produce only one myxamceba. Spores of Reticularia which had been dry for eight months germi- nated in thirty-five minutes at a temperature of 21°. Spores exposed to a temperature of 37° for only five minutes germinated in eleven minutes. The spores of Stemonitis flaccida germinated in one hour, those of Amaurochete in two and one-half hours, those of Didymium in four to five hours, while it took the spores of Stemonitis ferruginea in wood decoction three to five days to germinate. Some remarkable discoveries have been made with regard to an alternation of generations in the slime moulds connected with a so- called sexual act. Jahn, Kranzlin and Olive have worked upon this problem. The generation in all the Myxomycetes, including Ceratio- myxa, with the double chromosome number (8) (diploid condition) in the nuclei is of short duration. The nuclei of the swarm bodies, amce- boid bodies and the plasmodium have the single number (4) of chromo- somes. Union of the nuclei to form fusion nuclei with double SLIME MOULDS (MYXOMYCETES) 17 the number (8) of chromosomes immediately precedes the formation of the sporangia. The reduction division, which results in the forma- tion of spores, is preceded by synapsis, diakinesis and heterotypic nuclear division. Small nuclei and large nuclei are seen. The large nuclei are probably fusion nuclei. The small nuclei probably disintegrate. To the order MyxoGastRALeEs belong the majority of the Myxo- MYCETES (Figs. 2 and 3). Many are found on decaying wood as Dic- tydium cernuum with black spore contents, Arcyria nutans and A. Fic. 3.—A, B, Leocarpus fragilis. A, Sporangium, natural size; B, capillitium 200/1; C, Craterium leucocephalum sporangia, 6/1; D, Physarum sinuosum spor- angium, 6/1; E, F, Tilmadoche mutabilis; E, sporangia, 20/1; F, capillitium, 200/T. (A, C, D, after nature; B, E, F, after Rostafinski in Die nattirlichen Pflanzenfamilien 1S a, jon Sea) 5 punicea have net-like capillitia, the former with yellow, the latter with a red one. Lycogala epidendrum has a cinnabar-red plasmodium and a brownish-gray ethalium. Tvichia varia, T. chrysosperma, He- miarcyria clavata have yellow sporangia and golden-yellow spirally sculptured elaters, Reticularia lycoperdon has a large brown cake-like ethalium. The yellow plasmodium of Fuligo septica sometimes covers spent tan bark and is known as “‘flowers of tan.”’ It is one of the most generally distributed of slime moulds and the writer has found its wethalia on the bark of street trees and even on the bricks of the street pavements, as yellow-brown, cake-like fructifications crumbling readily 2 is) MYCOLOGY into a powder. The plasmodium of a species of Chondrioderma lives at the edge of melting snow fields, or even on the snow itself. The organ- ism of malaria frequently called Plasmodium malarie@ is not a slime mould, but rightly belongs to the group of Hamosporidie, a division of the Protozoa. | The slime moulds are cosmopolitan. Many of the same forms have been found in North and South America, the West Indies, Europe, Cape of Good Hope, Australia, New Zealand and Japan. The writer has used a manual of the Myxomycetes of Buitenzorg, Java, in the identification of species found near Philadelphia. About 214 species are represented in the British Museum collection. LABORATORY EXERCISE.—The writer has found in his experience as a teacher that time may be profitably spent by a class in mycology in the identification of the common slime moulds. The sporangia, ethalia and plasmodiocarps of the different kinds can be kept separately in different small pasteboard boxes and material out of these boxes can be distributed to the members of the class. The dried material is first treated with 70 per cent. alcohol to remove the air, and then the treated material is mounted for permanent preservation in glycerine jelly. The absorption of water by the glycerine jelly is prevented by a ring of asphalt. The “Guide to the British Mycetozoa exhibited in the Department of Botany, British Museum Natural History,” 1st Edition, 1895, 2d Edition, 1905, 3d Edition, 1909, has been used in classes at the University of Pennsylvania with much success. After the generic name has been determined, Lister’s ‘‘ British Mycetozoa”’ or MacBride’s ‘‘North American Slime Moulds” can be used to find the name of the species. BIBLIOGRAPHY Conarpb, H. S.: Spore Formation in Lycogala exiguum Morg. Iowa Acad. Sci., 17: 83, IgIo. Cooxre, M. C.: The Myxomycetes of Great Britain Arranged According to the Method of Rostafinski, 96 pp., 24 pls., London, Williams & Norgate, 1877. CooxkeE, M. C.: The Myxomycetes of the United States Arranged According to the Method of Rostafinski. Annals Lyceum, Nat. Hist., New York, 11: 378-4009, 1877. Cook, O. F.: Methods of Collecting and Preserving Myxomycetes. Botanical Gazette, 16: 263, 1801. DE Bary, ANTON: Comparative Morphology and Biology of the Fungi, Mycetozoa and Bacteria. Oxford at the Clarendon Press, 1887, especially pp. 420-453. SLIME MOULDS (MYXOMYCETES) 19 Harper, R. A.: Cell and Nuclear Division in Fuligo varians. Botanical Gazette, 30: 217, 1900. Harper, R. A.: Progressive Cleavage in Didymium. Science, new ser. 27: 341, 1908. Harper, R. A.: Cleavage in Didymium melanospermum (Pers.) Macbr. Amer. Journ. Bot., i: 127-143, March, 1914, with 2 plates. Harper, R. A. and Doncr, B. O.: The Formation of the Capillitium in Certain Myxomycetes. Annals of Botany, xxviii: 1-18, January, rg14, with 2 plates. HARSHBERGER, J. W.: Observations upon the Feeding Plasmodia of Fuligo septica. Botanical Gazette, 31: 198-203, Igor. Distribution of Nuclei in the Feeding Plasmodia of Fuligo septica. Journ. of Mycology, 8: 158-160, 1902. A Grass-killing Slime Mould (Physarum cinereum). Proc. Amer. Philos. Soe., 45: 271-273, 1906. Jann, E.: Myxomyceten Studien. Ber. Deutsch. Bot. Gesellsch. I. Dictydium umbilicatum, 19: 97-115, 1901; II. Arten aus Blumenau, 20: 268-280, 1902; III. Kernteilung und Geisselbildung bei den Schwirmen von Stemonitis flaccida, 22: 84-92, 1904; 1V. Die Keimung der Sporen, 23: 489-497, 1905; V. Listerella paradoxa, 24: 538-541, 1906; VI. Kernverschmelzungen und Reduktionsteilun- gen, 25: 23-26, 1907; VII. Ceratiomyxa, 267: 342-352, 1908; VIII. Der Sexualakt, 29: 231-247, III. Kr&nztin, H.: Zur Entwicklungsgeschicte der Sporangien bei den Trichien und Arcyrien. Archiv Protistenkunde, ix: 170-194, 1907. Lister, A: Notes on the Plasmodium of Badhamia utricularis and Brefeldia maxima. Annals of Botany, 2: 1-24, 1888. Lister, A.: On the Division of Nuclei in the Mycetozoa. Linn. Soc. Journ., xxxix: 520, 1803. Lister, A.: A Monograph of the Mycetozoa, 224 pp., 78 pls., p. 894. Lister, A: Guide to the British Mycetozoa Exhibited in the Department of Botany, British Museum of Natural History, rst Edition, 1895; 2d Edition, 1905; 3d Edition, 1909. MacBripe, T. H.: The North American Slime Moulds, being a list of all Species hitherto described from North America including Central America, pp. xvii+ 269: 16 pls., Macmillan Co., 1899. MacBripg, T. H.: On Studying Slime Moulds. Journ. Applied Microscopy, 2: 585-587, 1899. MacBring, T. H.: The Slime Moulds. Rhodora, 2: 75-81, 1900. MasseE, G.: A Monograph of the Myxogastres, 336 pp., 12 pls., London, Methuen & Co., 1892. OxtvE, Epcar W.: Cytological Studies on Ceratiomyxa. Trans. Wisc. Acad. Sci. Arts and Letters, xv: 753-773. Monograph of the Acrasiee. Proc. Boston. Soc. Nat. Hist., xxx: 451, 1902. Evidences of Sexual Reproduction in the Slime Moulds. Science, new ser. KV. 2605 1007. : Prnzic, O: Die Myxomyceten der Flora von Buitenzorg, Leiden, 1808. 20 MYCOLOGY Rex, G. A.: The Myxomycetes, Their Collection and Preservation. Botanical Gazette, 10: 290, 1885. SCHROETER, J.: Myxogasteres in Engler and Prantl; Die natiirlichen Pflanzenfam- ilien, 1: Abth. 1, pp. 1-35, 1889-92. ScHwarvTz, E. J.: The Plasmodiophoracez and Their Relationship to the Mycetozoa and the Chytrideze. Annals of Botany, xxviii: 227, 1914. STRASBURGER, E.: Zur Entwickelungegeschichte der Sporangien von Trichia fallax. Bot. Zeitung, xlili: 305-16; 321-3, May 16, 1884 and May 23, 1884. Sturcis, W. C.: The Myxomycetes of Colorado, No. 1. Science, ser. xii, No. I, pp- 1-43; general ser. No. 30, September, 1907; No. II. Science, ser. xii, No. 12, pp. 435-454, April, 1913; Colorado College Publications. Stureis, W. C.: A Guide to the Botanical Literature of the Myxomycetes from 1875 to 1912. Science, ser. xii, No. 11, pp. 385-434. June-September, 1912, Colorado College Publication. Zop¥, W.: Die Pilzthiere oder Schleimpilze, i-vi + 1-174 pp., Figs. 1-51, Breslau. 1885. CHAPTER III THE BACTERIA IN GENERAL CLASS II. SCHIZOMYCETES The name Schizomycetes comes from two Greek roots (oxife, I split + pixns, a fungus) which combined are equivalent to the term splitting fungi, or fission fungi in allusion to the manner in which the bacterial cells divide. The Germans call them Spaltpilze, which is the German way of expressing the same thing. The name bacteria is in American science used in a general sense to include all of the SCHIZOMYCETES without reference in particular to the genus Bacterium. In popular use, such as newspaper articles, these lowly plants are described as germs, microbes, or microdrganisms. These English synonyms are, however, inexact, having different shades of meaning and are used in different ways in common speech, as consultation with any large dictionary of our language will show. There is no ambiguity, if we speak of all the Scu1zomyceTEs as bacteria, or bacterial organisms. These plants are generally unicellular, or the single cells are united into a coenobium. These ccenobia are filamentous, sheet-like, or in groups, seldom arranged in fructification-like masses of definite form, as is the case with the Myxobacteria. All cells of the ccenobium are alike and only in the highest developed forms do we find a differentiation into basal cells and filament cells. The heterocyst, found in the blue- green alge, is totally absent. The cells of bacteria are the smallest of plant cells; for example: Micrococcus progrediens has a diameter of o.r5u and Spirillum parvum has a thickness of 0.1 to 0.3u, but yet smaller are the ultramicroscopic organisms, which have come into prominence recently as the cause of certain diseases. The smallest bacteria stand at the borderline of what is with the best lenses and optimum illumination the practical limit of microscopic vision. On the other hand, with the application of the ultraviolet light of short wave length in microphotography, it has been possible to obtain an image of small objects whose enlargement has been 4ooo-fold. It has been possible with the ultramicroscope of Siedentopf and Zsig- 21 bo iS) MYCOLOGY mondy to demonstrate small particles whose size is only many million times that of a millimeter. The accompanying figure (Fig. 4) adopted from Fuhrmann! represents the relative size of the spheric bacteria and the rod-shaped organisms, while the breadth of the largest known bacterial cell, that of Beggiatoa mirabilis, which approaches that of a human hair in thickness, is represented in the larger area where the width of the cell is twice its length. Fic. 4.—Diagram representing the relative sizes of spheric and rod-shaped bacteria (After Fuhrmann.) Diameter in u 1. Micrococcus progrediens 0.15 Spheric 2. Micrococcus uree D tomas Bacteria | 3. Sarcina maxima 4.0 4. Thiophysa volutans 7 to 18 Length in u Breadth in u 5. Pseudomonas indigofera 0.18 0.06 6. Bacillus influenze 4.2 0.4 7. Methane bacillus 5.0 0.4 Rod-shaped 8. Urobacillus Duclauxii 2 to 10 0.6 to0.8 Bacteria 9. Bacillus nitri . 3 to 8 2 to 3 10. Beggiatoa alba 2.910 5.5 s2ho toleng 11. Chromatium Okeni 10 to I5 SO 12. Beggiatoa mirabilis 10 to 20 Te5 £0240 The cells exhibit a definite cell wall which differs from that of the higher plants in not containing cellulose. The chemical character of the cell membrane indicates its close relationship to the living proto- plasm of the cell. Chitin has been found in the cell wall of some bacteria. Frequently the cell membrane undergoes a mucilaginous modification, so that the filamentous forms are surrounded by a sheath 1 FUHRMANN, F.: Vorlesungen iiber Technische Mykologie, Fig. 7, page 17. THE BACTERIA IN GENERAL 23 and the numerous individual forms are united into slimy, skin-like or lumpy masses known as zooglea. The interior of the cell shows no differentiation into nucleus and cytoplasm, but the nuclein in certain forms seems to be scattered in the plasma (Fig. 5). Considerable diversity of opinion exists as to the nature of the cell substance of bacteria. The uniform staining of the cell by ordinary methods suggests that the cell substance is all cyto- plasm without nucleus. An opposite opinion is that the cell substance is composed almost entirely of nuclear matter (chromatin) with perhaps a thin layer of ectoplasm. Another view is that of Zettnow (Zeitschr. f. Hyg., 1899: 18), who regards the cell body of bacteria as composed largely or almost wholly of chromatin mingled with varying amounts of cytoplasm. This, however, can be said, that it is fairly certain that bacteria contain both chromatin and cytoplasm which vary in amount and position in different cells (Fig. 5). The cell mem- = Fic. 5.—r, Chro- brane is mostly colorless; seldom does it appear ieee Cas ee Nek greenish or rose-red, as in the purple bacteria. Bacteria with a cen- When colonies of bacteria are colored, the coloring ee ou matin grains matter is an excretion product. which are considered Locomotion.—The movement of many bacteria is ele I gs equivalent ofa a true movement from place to place, not merely a nucleus. (From Brownian movement. It is accomplished in nearly sae ue £y, Second Edition, all cases by the presence of cilia, or flagella, which p. or. After by some are considered to arise directly from the ?“°"!"? cell membrane, by other investigators to arise from the ectoplasm within; its origin in some way associated with a blepharoplast. Which- ever view is the correct one, the motile filaments can in some large spirilla be seen in the living unstained organism, but generally it re- quires special methods of treatment and staining to make them out. Great differences exist as to their distribution. Some forms, as the cholera bacillus, have a single flagellum at one pole (monotrichous); others, as many spirilla, have a flagellum at each pole (amphitrichous) ; others, as certain large spirilla, have a tuft at one pole (lophotrichous) ; while others have cilia covering the whole cell, as the typhoid organism (peritrichous). Many organisms are without cilia, or flagella (atrichous), and hence are non-motile. 24 MYCOLOGY Cell Division and Reproduction.—As with other plant cells in general it may be said that growth is not conditioned on cell division. Growth is the enlargement of the cell, not merely a swollen condition, and this increase in size is within definite limits for each species, which can be determined by statistic study. As long as division is not preceded by nuclear division, the term fission is applicable. Certain students of the group claim that there is a division of the nuclear substance (Fig. 6), and Fuhrmann actually figures division of the nuclear mate- - rial in such forms as Bacillus nitri, Micrococcus butyricus, Spirillum volutans and the potato bacillus. Possibly then division of the nuclear substance precedes that of cell division, andif that phenom- enon is found general, the term fission is no longer applicable. ics 6. Ere: 4 Fic. 6.—Bacterium gammart. a, b, c, Cells with typical nucleus of nucleoplasm, surrounded by a nuclear membrane and by one or two karyosomes also showing karyokinesis; d, a filamentous bacterium from intestine of an annelid worm, Bryo- drilus chlorii, each cell with a nucleus. (From Marshall, Microbiology, Second Edi- tion, p. 89, after Vejdowsky.) Fic. 7.—Cells of Bacillus megatherium. 1, Polar granules as nuclei; 2, increase in size of nucleus at time of sporulation; 3, same; 4, change in size of nucleus which is surrounded by a membrane and becomes a spore. (From Marshall, Microbiology, Second edition, p. 90, after Penau) Cell division may take place quite rapidly under favorable conditions. Bacillus subtilis divides in thirty minutes; Vibrio cholera, every twenty minutes. The young cells attain full size in a short space of time. Bacteriologists have estimated, that if bacterial multiplication was unchecked and the division of each cell was accomplished inside of an hour that in two days the descendants of a single cell would number 281,500,000,000, and that in three days the offspring of a single cell would weigh 148,356 hundredweights. Lack of food, accumulation of bacterial products injurious to the organisms that formed them explain why their rapid multiplication is kept in check. THE BACTERIA IN GENERAL 25 The spores formed by the bacteria are of two kinds, arthrospores and endospores. Arthrospores are whole vegetative cells which by a thickening of their walls become resting spores. Some bacteriologists would not include arthrospores as true spores. The true spores are formed in the cells and differ from the cells in resisting greater heat and by other definite structural and physiologic qualities. (Fig. 7.) The shape of the cell may be altered with the formation of one or two spores within (endospores). In the hay bacillus, the spore occupies the center of the cell and is smaller than the original mother cell, hence the shape of the parent cell is not altered. Bacterium panis and Bacillus amylobacter become swollen in the middle when the spore forms so that the mother cell becomes spindle-shaped. The bacillus of lockjaw de- velops a spore at one end of the cell, which becomes drumstick-shaped, hence the German name trommelschlagel for such forms and the generic name Plectridium now given to cells that produce terminal spores. Bacillus amylobacter may develop one terminal spore, or two spores, one at each end of the cell, so that the mother cell becomes dumbbell- shaped. Bacillus inflatus may develop two spores also. Spores may germinate at the poleS, as in Bacillus Biitschli and B. amylobacter; at the equator, as in Bacillus subtilis and B. loxosporus, or obliquely, as in Bacillus loxosus. In germination resting spores absorb water, and become more or less swollen, when the spore membrane is dissolved and the germ tube protrudes. The classification of bacteria according to their special activities, or the products formed by these activities, is useful in presenting another phase of the subject to the mycologic student. The fact is noteworthy that we can group the various organisms into the photo- genic (light-producing), chromogenic (color-producing), thiogenic (sulphur-producing), zymogenic (ferment-producing), pathogenic (dis- ease-producing), saprogenic (decay-producing) and thermogenic (heat- producing) without reference to their morphology, or genetic rela- tionship. It is useful to be able to discuss the light, heat, color, etc., produced by these organisms as distinct phenomena worthy of experi- mental treatment. Photogenic Bacteria.—The phosphorescence associated with decaying haddocks, mackerel and other sea fishes, the faint glow seen on badly preserved meats (beef, mutton, veal) and sausages are produced by photogenic bacteria. Most success is obtained by using sea fishes in 20 MYCOLOGY experimenting with the phosphorescent bacteria, for these organisms require in their culture media from 2 to 3 per cent. of sodium chloride, besides the usual salts and peptone, the medium should contain some other source of carbon, such as sugar, glycerine, etc. The number of known photogenic bacteria is considerable. Migula names twenty- five species and Molisch twenty-six. A few need only be mentioned here, viz.: Bacterium phosphorescens Fischer; Bacillus photogenus Molisch; B. Juminescens Molisch; Microspira glutinosa (Fischer) Migula; M. luminosa (Beijerinck) Migula; Pseudomonas javanica (Kijkmann) Migula. The results of numerous experiments are that the production of light by bacteria is an exclusively aerobic phenome- non, for in the absence of oxygen, they are non-luminous. The light is sometimes strong enough that jars containing luminous bacteria can be photographed by the light emitted by the organisms within the jar. Chromogenic Bacteria.—Most bacteria are colorless and even in such forms in which color is associated with their growth on culture media, the organisms are colorless. The bacillus which causes the “bleeding host,” Bacillus prodigiosus, is colorless with the pigment in the form of granules scattered about between the bacterial cells. In other cases, the pigments and fluorescent substances are diffused in the culture medium outside the living cells. Hence, we may call such bacteria as chromoparous. The chromophorous species are those in which the protoplasm is actually colored. Such are some sulphur bacteria Chromatium and Thiocystis, and finally, there are some forms as Bacillus violaceus in which pigment is lodged in the cell wall, when we may call them parachromatophorous. Practically all of the colors of the spectrum are represented in the color productions of bacteria: violet (Bacillus violaceus), indigo (B. janthinus), blue (B. pyocyaneus), green (B. fluorescens), yellow (Sarcina lutea), orange (Sarcina aurantiaca) andred (B. prodigiosus). The erythrobacteria, or colored sulphur bacteria, are unique in the power of assimilating carbon dioxide in the presence of sunlight by the activity of bacteriopurpurin (a red coloring matter) which behaves like the chlorophyll of green plants. Thermogenic Bacteria.—Such substances as hay, silage, manure and cotton waste frequently become heated, the temperature inside the mass being raised to 60° or 70°C. This spontaneous heating is due to the respiratory activity of the thermogenic bacteria of Cohn (aerobic), which set up fermentation and putrefaction. The horticulturist uses THE BACTERIA IN GENERAL 2], manure, especially horse manure, in the construction of hot beds for the cultivation and forcing of young plants. In silos, the highest temperature recorded during the fermentation of the ensiled material was 70°C. but the best silage is secured by keeping the temperature below 50°C. Sometimes this spontaneous heating increases to the point of actual ignition (spontaneous combustion) and it may occasionally happen that such substances, as baled cotton, may be set on fire in this way, for Cohn found in damp cotton waste a Micrococcus which, when furnished with a plentiful supply of air, raised the temperature of the decaying mass to 67°C. Aerobic and Anaerobic Organisms.—Another useful division of bacteria is into those which are aerobic, requiring oxygen for their growth, and anaerobic, those which are indifferent to the presence of oxygen. The process of respiration in the aerobes is the same as in all ordinary organisms. Contrasted with the obligatory aerobes, we have those which thrive only: in the absence of oxygen (obligatory anaerobes). The growth of some of the latter is inhibited by small traces of oxygen (Bacillus tetani and some butyric organisms). One of the classic experiments in biology was devised by Engelmann (Botanische Zeitung, 1881 and 1882) to detect minute traces of free oxygen. It is a well-known fact that in the process of photosynthesis, or carbon fixation, by green plants that free oxygen is formed. Experi- ments have shown that not all the rays of the spectrum are equally effective in causing this chemic change. ‘The red rays between Fraun- hofer’s lines B and C are most effective and after them those just beyond the F line. It is these rays that are most active in the evolution of oxygen. Engelmann reasoned, that if a green alga was placed under the microscope and illuminated from below by a spectrum, so that the algal filament paralleled. the band of spectrum colors, that if aerobic organisms were introduced into water beneath the cover glass, these aerobic organisms would congregate in greatest numbers along the green alga at those points illuminated by the rays most effective in oxygen evolution by the plant. His anticipations were realized for he found a grouping of the aerobic bacteria in the neighborhood of the B and C Fraunhofer lines and beyond the F line, where theory told him to expect the greatest photosynthetic activity. Such minute quan- tities of oxygen must be formed by a filamentous green alga, that this experiment becomes a microchemic test for the gas. CHAPTER IV CLASSIFICATION OF BACTERIA Classification According to Nutrition.—An illuminating classification of bacteria has been based on their mode of life, where three biologic groups may be recognized: the prototrophic, the metatrophic and the paratrophic bacteria. The prototrophic bacteria, which include the nitrifying bacteria, bacteria of root nodules, sulphur and iron bacteria and erythrobacteria, are those which either require no organic com- pounds for their nutrition, or which given a small amount of organic carbon can derive all of their nitrogen from the atmosphere, or which with a minimum of organic matter can derive energy by breaking up inorganic bodies. The sulphur bacteria live in sulphur springs where hydrogen sul- phide (H2S) is formed by putrefaction of dead animals and plants. The sulphur bacteria in such places form a white furry growth on the rotting vegetation. Here the H2S is attacked and water and sulphur are formed, H2S +O = H;0+4+ 5S. The sulphur is deposited in the living cells of the bacteria as yellow amorphous granules, which impart to the organism a yellow color. To explain the facts observed, we need assume only that the protoplasm increases the oxidizing power of the atmospheric oxygen and renders it active. The conversion of HeS into water and S gives 71 calories and the further oxidation of the freed sulphur into sulphuric acid 2109 calories. The fact that the sulphur bacteria can live without organic compounds together with their inability to live without sulphur indicates that it is the oxidation of the sulphur alone which takes the place of respiration in other organisms. The ferrobacteria live in stagnant pools in marshy places. On such pools of water, we find a greasy scum of ferric hydroxide Fe(OH); together with organic matter and some phosphate of iron. The ferric compounds are reduced by the action of reducing substances formed by putrefaction to the ferrous state which are dissolved by carbon dioxide CO, and unite also with it to form ferrous carbonate. The atmospheric oxygen can convert this carbonate back to ferric hydroxide, but Wino- 28 CLASSIFICATION OF BACTERIA 29 gradsky has shown that the process is assisted by the iron bacteria and the ferric hydroxide is deposited as a tube about such organisms as Leptothrix ochracea. hese tubes, or sheaths, are deposited later as bog iron ore. The nitrifying bacteria are found in the soils of our gardens, fields and meadows and in virgin soil derived from places the world over. Winogradsky has discovered that the conversion of ammonia into nitric acid takes place in two steps and that bacteria are effective in both of these operations. One set of bacteria belonging to the genera Nitrosococcus and Nitrosomonas oxidize the ammonia to nitrous acid, or its nitrite, and the conversion of this nitrous acid (nitrite) to nitric acid, or its nitrate, is accomplished by Nitro- bacter. Nitrosococcus is a non-motile spheric cell, 3u in diameter, found in soil from South America and Australia, while Nitrosomonas europea found in all soils from Europe, Africa and Japan is a short ellipsoidal motile form 0.9 to tm wide and 1.2 to 1.8u long with a short cilium. Nitrosomonas javanensis from Java is almost spheric, 0.5 to o.6u, with a cilium 30u long, which is the longest known among bac- teria. Nitrobacter are minute non-motile rods : Fic. 8.—Roots of soy (0.54 X 0.25u). These organisms are of the pean ecehispida, with greatest importance in putting the nitrogen of tubercles. (After Conn, the soil into a form which can be absorbed by ete ee the roots of the cultivated plants. The bacteria which produce the nodules (Fig. 8) on the roots of leguminous plants are probably the same the world over and to them Beyerinck has given the name of Bacillus radicicola, while Frank called them Rhizobium leguminosarum (Fig. 10). When the seeds of clover, or some other leguminous species are planted, and soon after the primary root appears with its root hairs, Bacillus radicicola, attracted chemo- tactically to the fine root hairs, penetrates the walls of these root hairs by ferment action. So many bacilli enter the root hair cells that they form slimy cords, almost hyphe-like, as they move into the middle cortex cells of the root. Here in the cortex cells, the microdrganisms form nests or pockets, that are filled with the nodule-producing bacteria 20 MYCOLOGY (Fig.9). The presence of these bacteria causes the formation of swell- ings, tubercles, or nodules on the roots of the leguminous plants. Here Bacillus radicicola remains, utilizing free atmospheric nitrogen until about the time of flowering of the host, when it begins to assume in- volution forms, enlarging considerably and assuming S-shaped or Y-shaped forms (Fig. ro). Then they are gradually absorbed by the Fic. 9.—Cells of root tubercle of Lupinus angustifolius magnified to show the bacteria; four cells with nuclei. (After Moore, Geo. T., Yearbook U. S. Dept. Agric., 1902,’pl. xxxix.) green leguminous plants and their substance is transformed into a form of nitrogenous substance, which is utilized by the leguminous host, either as food, or stored as nitrogenous reserve supplies. The nodule becomes emptied of its contents and remains as a hollow sac, enough of the organisms being returned to the soil to seed it and provide for infection of other leguminous crops that may follow. The growth CLASSIFICATION OF BACTERIA 31 of these useful organisms in the soil is stimulated by aeration, by some organic material, by proper soil drainage, by the application of lime which overcomes soil acidity. The farmer becomes independent of the ordinary nitrogenous fertilizers, which are expensive, by plowing under the leguminous crops, which on decay yield up to the soil the nitrogenous substance largely accumulated by bacterial action where it is available to that large class of nitrogen-consuming plants such as the grasses, weeds, root crops, fruit crops and the like, which are de- pendent on the soil nitrates for their nitrogen. The leguminous plants as nitrogen-storing plants should, in an up-to-date rotation, be alternated with the nitrogen-consuming crops. & é 8 « on / wy fe << * } 4 = / Fic. 10.—Left, branching forms of bacteria from clover tubercle ( 2000); ’ right, rod forms from fenugreek tubercle (xX2000). (After Moore, Geo. T., Yearbook U.S. Dept. Agric., 1902, pl. xxxix.) Metatrophic Bacteria.—The metatrophic bacteria include the zymo- genic, saprogenic and saprophile bacteria, which cannot live unless they have organic substances at their disposal, both nitrogenous and carbonaceous. They flourish where organic substances and foodstuffs are exposed to decay in impure water and in the waste from animal bodies. Many of them produce profound fermentative changes (zymogenic bacteria) in bodies. Others cause putrefaction and decay (saprogenic bacteria), while others develop in media which have been decomposed by saprogenic species and as saprophile organisms break these substances up into simpler chemical form. 20 MYCOLOGY Fermentation is well exemplified in an old and well-known process, the conversion of alcohol into acetic acid by a number of organisms morphologically very similar. Hansen considers that there are three different species concerned in the acetic fermentation, namely, Bacterium aceticum, B. Pasteurianus and B. Kiitzingianus, which are non-motile, medium-sized rods often in chains and forming pellicles which appear on the surface of the liquid, afterward sinking to form in the liquid a deposit known as mother of vinegar. The changes which take place in the conversion of alcohol to acetic acid may be expressed as follows: CH;.CH2.OH + O = CH;.CHO + H,O Alcohol Aldehyde CH;3.CHO + 0 = CH;.COOH [Aldehyde Acetic Acid This is conducted in barrels with wood shavings, where the alcoholic fluid trickling over the shavings coated with the bacteria, and in contact with the air, is changed to acetic acid. Lactic acid fermentation is important to man, because upon the changes in milk by the lactic acid organisms depends the manufacture of a considerable number of valuable products of the dairy, such as buttermilk and cheese. This fermentation is an aerobic process whose optimum is found between 30° and 35°C. There is a considerable number of bacteria capable of converting milk sugar into lactic acid, suchas Vibrio cholere, Bacillus prodigiosus and others, but the true lactic acid bacteria are those which are the cause of the souring of milk. Formerly, they were all classed as Bacterium acidi lactici, but recent investigations have shown that not one species but a considerable number are at work, sometimes one form; sometimes another being active. A common kind is a short non-motile rod, 0.54 X 1 to 2n, facultatively anaerobic, known by such names as Bacterium acidi lactict, B. aerogenes, and probably comprising several races of one species. The true lactic acid fermentation is the change of lactose, or milk sugar, into lactic acid. As lactose is not directly fermentable it must be converted into such simple sugars as glucose and galactose. The following equation approximately represents the chemic change involved. Ci2H201 + H2O = CeHi206 + CoHi205 5) sactose Water Glucose Galactose CsHi206 = 2C3H6O03 _ Lactic Acid 2 I CLASSIFICATION OF BACTERIA 33 Several other important fermentations are due to bacteria, as the causal organisms, namely, the butyric, cellulose, and mucilaginous fermentations. The retting of vegetable fibers, the manufacture of indigo, the curing of tobacco are all dependent on bacterial fermentations. The saprogenic organisms are concerned with decay, or putrefac- tion. The decomposition of dead animal and plant bodies is far from being a simple putrefactive process. Nitrogenous and non-nitrogenous bodies are both concerned in the putrefactive changes and they are broken down into simpler nitrogenous and non-nitrogenous compounds, or even elements. Proteins are split up into albumoses and peptones, aromatic compounds (indol and skatol), amino compounds (leucin, tyrosin, glycocol), fatty and aromatic acids and inorganic end products (nitrogen, ammonia, hydrogen, methane, carbon dioxide and hydrogen sulphide). Ptomaines and other poisonous bodies are formed known as toxins, a name applied indiscriminately to all bacterial poisons.’ The activity of all these organisms in causing decomposition of animal and plant products is important in preserving the circulation of carbon and nitrogen in nature. Without such destructive changes, the elements carbon and nitrogen would be combined in such a form as to be forever lost to animals, and plants. In the dissolution of these complex bodies, the simpler chemic compounds are released and can be used over again by living animals and plants. Much should be made of the circulation of the elements in nature and the two chief cycles are the carbon cycle and the nitrogen cycle with a sulphur and phosphorus cycle as well. There are two main processes in organic life: the constructive processes (anabolism), and the destructive processes (katabolism). Construction is accomplished mainly by green plants and the prototrophic bacteria. Destruction is the work of animals, metatrophic and paratrophic organisms; which have to break down organic matter. to live. Thus the elements of the organic world are kept in perpetual circulation. Paratrophic Bacteria.—These organisms occur only in the tissues | and vessels of living organisms and are, therefore, true parasites. Many of them are responsible for animal and plant diseases and the special types, as far, as they concern this book, namely, those which induce 1Consult Lathrop, Elbert C.: The Organic Nitrogen Compounds of Soils and Fertilizers. Journ. Franklin Inst. 183: 169-206, Feb.; 303-321, Mch.; 465- 498, Apr., 1917. 3 34 MYCOLOGY diseases in plants will be considered at length in another section. Most attention has been paid to diseases of animals and man due to bacteria and the number of special works dealing with the subjects of bacteriology, pathology, immunity and disease would form a library. Nearly every phase of the relationship of bacteria to animals and man has been cultivated, and microbiology has been placed on a firm founda- tion, as a subject of human inquiry. ‘The field is too vast for one man to cultivate it, and hence, we find a narrow specialism perhaps more than in any of the other departments of biologic investigation. An interesting phase of the relationship of parasite and host has come recently into the scientific limelight. Dr. Erwin F. Smith in the study of the organism which produces the crown gall of woody plants, Pseudomonas tumefaciens (Fig. 143), finds that the growth and formation of the tumors suggests the development of cancer in man. He thinks the formation of tumors in plants away from the point of infection suggests a similarity (Fig. 158). SYSTEMATIC ACCOUNT OF THE BACTERIA For the use of students who may not have access to larger works on bacteria and who would like a short systematic account of the bacteria the following synopsis is given. : ORDER I. EUBACTERIALES.—The organisms of this order are unicellular, or in plate-like, spheric, or filamentous coenobia, if imbedded in a slimy matrix, then not of a definite form. FamILy 1. CoccAcE#.—Single spheric cells. Division in one, two or three directions. Streptococcus.—Division always in one direction, coenobia, there- fore, chain-like, cells without flagella. Pathogenic: S. erysipelatos, specific germ of erysipelas to be distinguished with difficulty from S. pyogenes. Not pathogenic: S. mesenterioides (Leuconostoc mesen- terioides), occurring in mucilaginous masses in the molasses waste of sugar factories, and its presence disastrous to the industry. Micrococcus.—Division in two directions, ccenobia, sheet-like, without flagella. Pathogenic: Micrococcus pyogenes aureus (= Staphylococcus pyogenes aureus), the cause of pus formation and purulent discharge from wounds, M. gonorrhee (= Gonococcus gonor- | rhee@) specific germ of gonorrhoea. Not pathogenic: M. aurantiacus, luteus, cinnabareus producing pigments. CLASSIFICATION OF BACTERIA 35 Sarcina.—Division in three planes, coenobia in bales, or pockets, ‘no flagella. S. ventriculi, frequent in the stomach of men, but non- pathogenic. S. aurantiaca, flava, lutea are chromogenic. S. rosea with red cell contents occurs in swamps, or colors the soil a rose-red color. Planococcus.—Division and ccoenobic formation as in Micrococcus, flagellate. P. citreus produces a yellow color. Planosarcina.—Division and ccenobic formation as in Sarcina, flagellate. Famity 2. BacrEeRIACEx.—Cells longer or shorter cylindric, straight, or at least never spirally twisted. Division always at right angles to the long axis, and only after a preliminary elongation of the cell. The rods may separate early in some species, in others they remain united for a considerable time as longer or shorter filaments. Endospores are frequent, rare, or wanting. Flagella may or may not be present. Bacterium (Ehrenberg char. emend.).—Cells as longer or shorter ‘cylindric rods, often forming filaments of considerable length. With- out flagella. Endospore formation in many species, absent in others. Erwin F. Smith (“Bacteria in Relation to Plant Diseases’: 168 to 171) believes that bacteriologists should substitute Bacterium for Pseudomonas as the older generic name, and he would establish a new generic name A planobacter for the non-motile forms generally referred to Bacterium. This distinction is not adopted inthis text-book. Pathogenic: Bacterium (A planobacter) Rathayi the cause of Rathay’s disease of the orchard grass; B. michiganense the cause of the Grand Rapids (Mich.) tomato disease; B. anthracis the first organism deter- mined to be the cause of disease, causing anthrax or splenic fever; B. mallei specific in glanders in men and horses; B. pneumonia, the cause of pneumonia; B. tuberculosis responsible for tuberculosis (consumption, phthisis) in man and animals. It can be distinguished by its staining reactions. If stained with carbol fuchsin and then treated with dilute nitric acid (1:5), the stain remains fast, while with other organisms, the stain will be washed out. After this treatment the tissues can be treated with methylene blue for differential staining. B. lepre, the organism of leprosy; B. influenze, the cause of influenza, or grippe; B. diptheritidis, the causal bacterium of diphtheria; B. pestis, specific in the disease known as the plague, which as the Black Death devastated 30 MYCOLOGY London in 1665 in which 70,000 persons perished. It is carried by infested rats. Non-pathogenic: B. aceticum sets up in alcoholic solution the acetic acid fermentation and its films later form mother of vinegar. B. acidi lactici ferments sweet milk transforming it into sour milk where the acidity is due to lactic acid. B. phosphoreum is a phosphorescent fresh-water organism. Bacillus (Cohn char. emend.).—Cells straight, rod-shaped to ovoid, long or short, sometimes united into filaments. Motile by wavy, bent flagella scattered over the whole surface of the cell. Formation of endospores frequent. Motility may be active for a time, and then is lost. Pathogenic: B. muse causes the Trinidad banana disease; B. tracheiphilus is responsible for the wilt of cucurbitaceous plants; B. amylovorus, the pear-blight organism; J. carotovorus, specific in soft rot of carrot; B. aroide@, an organism which causes soft rot of the calla; B. tetant, the causal microbe in tetanus, or lockjaw, is found in the soil and may enter the skin or superficial muscles of man through a pin prick, or rusty nail point; B. typhi, the typhoid bacillus. Non-° pathogenic: Bacillus subtilis, the hay bacillus found in hay infusion, and is the cause of decay. 8B. coli in the alimentary canal of animals and men and in the water polluted by sewage. B. butyricus produces butyric acid fermentation and the coagulation of casein. B. radicicola (= Rhizobium leguminosarum) lives in the roots of leguminous plants and forms the root tubercles or nodules (Figs. 8,9, 10). B. amylobacter (= Clostridium butyricum) ferments cellulose, dissolves casein and is useful in the retting of plants for fiber production. B. prodigiosus is found on many food substances imparting to them a dark red color. B. calfactor appears in hay infusions, where it produces a rise of tem- perature. B. putrificus, a widely distributed organism. Many bacilli that occur in the ocean are luminous. Pseudomonas.—Cylindric bacteria, sometimes long, sometimes short, occasionally in threads. Locomotion accomplished by polar flagella, the number of which may vary from one to ten, most frequently one flagellum is present, or three to six. Endospores are formed, but are rare. ‘The following are the causes of diseases in cultivated plants: Pseudomonas campestris is responsible for the black rot of cabbage and other cruciferous plants. Ps. hyacinthi causes the yellow disease of hyacinths. Ps. vascularum is associated as the causal bacterium in CLASSIFICATION OF BACTERIA 37 Cobb’s disease of sugar cane. Ps. pyocyanea causes blue pus. Ps. putida occurs in water, where it develops a green fluorescent pigment. Ps. syncyanea produces in milk a blue coloring matter (blue milk). Ps. europea belongs to the group of organisms which cause nitrification. FAMILY 3. SPIRILLACE#.—Spirally wound or bent cells with occa- sional endospore formation, usually motile. Cell division transverse to the long axis of the cell. Spirosoma.—Spirally bent, rigid cells usually rather large and with- out flagella. Unicellular free or enveloped in a gelatinous capsule. Only a few species are known. Micros pira.—Comma-shaped, or sausage-shaped, single, or united cells, motile by means of a single, wavy, polar flagellum (rarely two or three flagella), rarely longer than the cell. Endospores unknown. Usually united with the next genus. Spirillum.—Rigid rod-shaped cells of varying thicknesses, lengths and pitch of spiral turns, hence, either as long screws, or loosely wound. Flagella occur at one or both ends of the cells as polar tufts varying in number from five to twenty. In some species, endospore formation has been observed. Sp. comma is the cause of asiatic cholera and is found in cultures often in long spirally wound filaments. There are many non-pathogenic spirilla in water from rivers and ponds as 5S. danubicum in the Danube, Sp. berolinense in Spree water, Sp. rufum in stagnant water. Sp. rufum forms blood-red slimy masses between decaying alge. Spirocheta.—Thin, flexible, snake-like, motile cells usually quite long without observed flagella and endospores, and unsegmented. Spirocheta Obermeiert is the cause of relapsing fever (febris recurrans). S. (Treponema) pallida is the organism of syphilis. S. dentium is found associated with the teeth in man. FAMILy 4. PHYCOBACTERIACEH (CHLAMYDOBACTERIACE#).—Cylin- dric cells united into sheath-surrounded threads and reproducing by motile or non-motile conidia, which arise from the vegetative cells without a resting stage. Streptothrix (= Chlamydothrix, Leptothrix, Gallionella).—Non-motile, cylindric cells in unbranched threads possessing a sheath of varying thickness. Septa vague. Reproduction is accomplished by roundish, non-motile conidia arising from the vegetative cells. S. fluitans in water. 38 MYCOLOGY Crenothrix.—The cells are arranged in unbranched threads attached at one end and enlarging toward the distal extremity. Filaments covered by a rather thick sheath. The reproductive cells are non- motile conidia, which on discharge immediately germinate. Crenothrix polyspora in springs and water pipes, where it forms attached slimy growths. The sheaths in iron waters are impregnated with iron oxidhydrate. Phragmidiothrix.—Cylindric. cells with delicate, scarcely visible sheath. The cells of the filament are at first in one plane which later divide in three directions to form clumps or packets of cells. Later the single cells round off and become free. Ph. multiseptata with fila- ments 3 to 124 broad and rooy long attached to the bodies of crustacee. Cladothrix (Spherotilus in part).—The fixed and often tufted filaments form delicate sheaths. The cells are cylindric and by inter- calary growth may break laterally through the sheath to form false dichotomous branches. Reproduction is accomplished by motile swarm spores (gonidia) which bear a tuft of flagella a little to one side of a pole. Cladothrix dichotoma occurs frequently in stagnant water, attached and forming furry growths. The following species occur in the soil: C. rufula, C. profundus, C. intestinalis, C. fungiformis, while C. intrica has been isolated from sea water and sea mud. FaMILy 5. THIOBACTERIACEZ (BEGGIATOACEZ).—Cells with sul- phur inclusions, unpigmented, or colored rose, red or violet by bacterio- purpurin; never green. The plants are generally filamentous with division transverse to the long axis. Thiothrix.—Unequally thick attached filaments encased in a delicate, scarcely visible sheath. Rod-shaped conidia are formed at the ends of the threads. Th. nivea is found in sulphur springs and in stagnant water. Beggiatoa.—Sheathless, free-filamentous bacteria, motile by means of an undulating membrane. Cells with included sulphur granules. Spore formation unknown. B. alba is found in dirty water, drain water from sugar factories and attached to decayed plants in sulphur springs. B. mirabilis forms white growths on dead marine alge. The colored sulphur bacteria, sometimes placed in the family RHODOBACTERIACE®, belong here. They have rose, red or violet cell contents due to the presence of bacteriopurpurin (see ante). The im- CLASSIFICATION OF BACTERIA 39 portant genera according to Erwin F. Smith (“Bacteria in Relation to Plant Diseases,’”’ I: 163) are Yhiocystis, Thiocapsa, Thiosarcina, Lamprocystis, Thiopedia, Amebobacter, Thiothece, Thiodictyon, T hiopoly- coccus, as well, as the three genera Chromatium, Rhabdochromatium, Thios pirillum. Famity 6. ACTINOMYCETACE (Position doubtful).—Radially ar- ranged branched filaments in colonies, non-motile. Filaments divid- ing into oidia-like reproductive cells. Actinomyces chromogenes occurs in soil. A. bovis is the cause of lumpjaw in cattle and occasionally in man. The plant occurs in rosettes usually 30 to 40ou in diameter. The filaments which are often. curved sometimes spirally exhibit true branching and are interlaced in a network. Recently Youngken (Amer. Jour. Pharm., September, 1915) has described the foundation of the large swellings (mycodomatia) on the roots of the waxberry, Myrica carolinensis, and other species, as due to a species of ray fungus, Actinomyces myricarum, that abun- dantly fills infested cells in the cortex of the tubercular swellings. A. thermophilus is found on hay and manure. ORDER II. MYXOBACTERIALES.—Individual plants en- closed in slimy masses which assume more or less regular fructifica- tion-like shapes. FAMILY 1. MyXxoBACTERIACEZ.—Erwin Baur and Roland Thaxter have studied these forms most intimately. The plants of this family consist of motile, rod-like microdrganisms, with a gelatinous base and forming false plasmodioid aggregations preceding a cyst-producing, quiescent state in which the rods may be encysted in groups or con- verted into spore-masses. The slightly reddish rods in the vegetative stage are elongate, sometimes 15 long and vary little in size in the different genera and species. Cell division is by fission and the active rods show a slow sliding movement without organs of locomotion. The vegetative phase in artificial cultures usually lasts about a week, or even two weeks, and the formation of cysts which follows must be more rapid in nature. These organisms are found in moist places on decay- ing wood, dung, funguses and lichens, growing best, according to Baur, at 30°C. Three genera are included in this family. Chondromyces.—Rods producing free cysts within which they remain unchanged. ‘The cysts are various, sessile or developed on a stalk (cystophore). 40 MYCOLOGY Polyangium (= Myxobacter, Cystobacter).—The rods form large rounded cysts one or more of which are free inside a gelatinous stalked matrix. M yxococcus.—Slender rods which swarm together, after a vegetative phase, to form well-defined, more or less sessile or stalked encysted masses of coccus-like spores. BIBLIOGRAPHY Appott, A. C.: The Principles of Bacteriology, gth Edition: Lea & Febiger, rors. pE Bary, A.: Comparative Morphology and Biology of the Fungi, Mycetozoa and Bacteria. Oxford at the Clarendon Press, 1887. Baur, Erwin: Myxobakterien Studien. Archiv fiir Protistenkunde, v Bd., Heft I, 92-121, 1904. BuCHANAN, EstELLE D. and Ropert EARLE: Household Bacteriology. The Macmillan Co., New York, 1914. CHESTER, FREDERICK D.: A Manual of Determinative Bacteriology. The Mac- millan Co., 1914. Conn, H. W.: Bacteria, Yeasts, and Molds in the Home. Ginn & Co., Boston, 1903. Duccar, Benjamin M.: Fungous Diseases of Plants. Ginn & Co., Boston, 1909. Exuis, Davin: Outlines of Bacteriology (Technical and Agricultural), Longmans, Green & Co., 1909. EnctER, Apote and Gitc, Ernest: Syllabus der Pflanzenfamilien. Berlin, ror2, Siebente Auflage, pp. 1-5. Eyre, J. W. H.: The Elements of Bacteriological Technique. Philadelphia, W. B. Saunders & Co., 1902. FiscHer, ALFRED, transl. by Jones, A. Coppen: The Structure and Functions of Bacteria. Oxford at the Clarendon Press, 1goo. FuHRMANN, Dr. Franz: Vorlesungen iiber technische Mykologie. Jena, Gustav Fischer, 1913. Hiss, Putre H. and Zinsser, Hans: A Text-book of Bacteriology. D. Appleton (te (Cos WO Se JorpAN, Epwin O.: A Text-book of General Bacteriology, 3d Edition. Phila- delphia, W. B. Saunders & Co., 1913. Kisskatt, K.: Bakteriologie Zweite Auflage. Erster Teil von Prakticum der Bakteriologie und Protozoologie. Jena, Gustav Fischer, 1909. Kuster, Dr. Ernst: Anleitung zur Kultur der Mikroorganismen. Zweite Auflage, Leipzig und Berlin, 1913. Larar, Dr. Franz: Technical Mycology. The Utilization of Microérganisms in the Arts and Manufactures. London, Charles Griffin & Co., vol. i, 1898. Lipman, Jacos G.: Bacteria in Relation to Country Life. The Macmillan Co., New York, 1908. MARSHALL, CHARLES E. and Orners: Microbiology for Agricultural and Domestic Science Students. Philadelphia, P. Blakiston’s Son & Co., rgrr. CLASSIFICATION OF BACTERIA 41 Meyer, Dr. Arruur: Practicum der botanischen Bakterienkunde. Jena, Gustav Fischer, 1903. Murr, Ropert AND RircHre, JAMES: Manual of Bacteriology. The Macmillan Co., 1913. NEWMAN, GEoRGE: Bacteria. Especially As They Are Related to the Economy of Nature to Industrial Processes and to Public Health. G.P. Putnam’s Sons, New York, 1899. PARK, Wit1tAM H. and WriitAms, ANNA W.: Pathogenic Microérganisms. Lea & Febiger, Philadelphia, 1914. PERCIVAL, JOHN: Agricultural Bacteriology Theoretical and Practical. Duck- worth & Co., London, rgto. Prescott, SAMUEL C. and WINSLow, CHARLES EDWARD A.: Elements of Water Bacteriology, 3d Edition. John Wiley & Sons, New York, 1913. QuenL, A.: Untersuchung iiber Myxobakterien. Zentralblatt fiir Bakteriologie, II Abt., xvi Bd., 1906. SmitH, Erwin F.: Bacteria in Relation to Plant Diseases, vol. i, 1905; vol. ii, 1911; vol. iii, 1914. Publication No. 27, Carnegie Institution of Washington. THAXTER, ROLAND: On the Myxobacteriacee, a New Order of Schizomycetes. Bot. Gaz., xvii, 1892; Further Observations on the Myxobacteriacee. Loc. cit., xxili, 1897; Notes on the Myxobacteriacee. Loc. cit., xxxvii, 1904. WETTSTEIN, RicHARD R. von: Handbuch der Systematischen Botanik Zweite Auflage, 1911: 69-83. CHAPTER AY. CHARACTERISTICS OF THE TRUE FUNGI CLASS III. EUMYCETES The true fungi or hyphomycetes (6¢7, a web + yixns, a mushroom) are thallophytes in which the thallus, as the Greek derivation implies, consists of a system of threads (kyphe) which form a cobwebby struc- ture known as the mycelium (Fig. 11). A single thread of the mycelium is an hypha (plural hyphe) and a hypha may be unicellular, or multi- cellular. All true fungi are colorless, that is they are chlorophylless; and although they may have other pigments present, yet in the absence of chlorophyll, they are dependent plants. As dependent plants, they must get their organic food from extraneous sources, and as all organic matter is either dead, or living, a natural classi- fication of fungi into saprophytes and parasites can be made. A saprophyte (campos, rotten + gurov, a plant) is any Fic. 11.—Gray mould, Mucor, 5 5 5 : i showing myceliumiand thesporan. Organism. which derives its seme meme gia on upright sporangiophores. supply from dead, or dead and decaying (After Conn.) ; 5 a ; animal or plant organic material, while a parasite (mapdo.ros, one who lives at another’s expense) is an organism, which exists at the expense of living animals, or plants (Fig. 12). But some saprophytes may change their mode of nutri- tion and become parasitic; such saprophytes are called facultative parasites, while those which retain their saprophytism under all condi- tions are obligate saprophytes. Again some parasites can adjust their methods of nutrition, so that they can become saprophytes. Such parasites are called facultative saprophytes, while those organisms which are always parasitic are obligate parasites. These distinctions are useful, but it should be emphasized that there is no absolute border- line between one condition and the other. There are imperceptible 42 7a CHARACTERISTICS OF THE TRUE FUNGI 43 gradations which preclude an absolute pronouncement as to whether a plant is a saprophyte, or a parasite.' Botanists generally concede that the true fungi have been derived from filamentous algal ancestors and the groups of alge from which the principal forms of fungi have N ws PRA NA Aa ii 1 TAT TE Zp Zi) AX, Fic. 12.—Russula nigricans parasitized by Nyctalis asterophora. (After Brefeld.) been derived are fairly well known. For example, it is believed that such fungi as belong to the order OOMYCETALES have been derived 1 Masser, GeorGE: On the Origin of Parasitism in Fungi. Annals of Botany, Xviii: 310. Warp, H. M.: Recent Researches on the Parasitism of Fungi. Annals of Bot- any, XIX: I. Bancrort, C. K.: Researches on the Life History of Parasitic Fungi. Annals — of Botany, xxiv: 359, I91o. ‘ 44 MYCOLOGY from a green alga like Vaucheria. With our present knowledge, it is impossible to name any one existing alga as the progenitor of a definite fungous form, but we are safe in assuming in a general way that certain phyla of fungi have been derived from certain phyla of alge, by the loss of chlorophyll and in the loss of an independent existence. Another view, which is open to argument, is that certain of the prototrophic Fic. 13.—Development of Mucor mucedo. a, b, c, d, Stages in the formation of zygospore; f, sporangium; g, mature sporangiospores; h, one germinating. (After Schneider, Pharmaceutical Bacteriology, p. 142.) filamentous bacteria to which attention has been previously called have been the direct progenitors of certain of the filamentous fungi, but on account of the character of the reproductive organs in the lower true fungi their derivation from green alge is the more probable, and mycologists even speak of the algal fungi referring especially to aquatic genera, such as Saprolegnia, which like their algal ancestors not only retain the general morphologic features of the alge, but also live in an CHARACTERISTICS OF THE TRUE FUNGI 45 aquatic medium, and the success of the process of fertilization depends on the presence of free water. Such fungi form a subclass of EUMY- CETES, the PHYCOMYCETES. The vegetative organs of fungi are concerned with the absorption of food, the assimilation of the food and in the nutrition of the organs of fructification which together form the reproductive system. ‘That the student may appreciate the morphology of the vegetative organs of the fungi, three examples from widely divergent orders will be chosen by way of illustration. A common mould is Mucor mucedo which appears on horse manure. If a spore of this fungus is placed in a nutri- tive medium, its wall breaks and there protrudes a germ tube rich in protoplasmic ‘contents (Fig. 13, #). This germ ttibe grows in length into an hypha without the development of partition walls dividing it into shorter cells. This hypha branches and rebranches in its growth over the nutrient substratum spreading in all directions, if unimpeded by other organisms growing on the same food substance. ‘The ultimate branches of this mycelium, which is throughout unicellular, are much attenuated, fine hyphe representing the end ramifications of larger and coarser hyphz nearer the point of origin of the whole mycelium (Fig. 13). The finest hyphe usually enter the substratum, while the coarser, stronger hyphe form a cobwebby mass over its surface. We can distinguish therefore the feeding hyphe, which are rhizoidal hyphe, and the aerial hyphe in which probably the metabolic changes are most active where the mycelium is in open contact with the air. Later, when the mycelium is well established on the nutrient substratum, erect vertical hyphe appear at indefinite points on the larger aerial hyphe. These are the fruiting hyphe, or sporangiophores, which ultimately cut off a terminal cell which becomes the sporangium, or case, in which the reproductive cells or spores are formed, while the end of the sporangiophore projects into the interior of the sporangium as a columella (Fig. 13, /). The common green mould, Penicillium glaucum,may be taken as the second illustration (Fig. 14). If we sow a spore on nutrient agar ina Petri dish after a few hours the spore swells and there emerges a germ tube which at first is undivided by a partition wall. Later, as the older hyphz branch to form new ramifications, cross-partitions are formed which divide the mycelium into short cells, so that in that respect the mycelium of Penicillium differs from that of Mucor. The hyphal 46 MYCOLOGY branches are coarser in Penicillium and do not form the fine-pointed ends found in Mucor. The presence of transverse walls in the fungi is thought of sufficient importance to make a subclass known as the MYCOMYCETES to contain all of the true fungi EUMYCETES which have a mycelium which is multicellular in contradistinction to those which have unicellular mycelia and that form the subclass PHYCOMYCETES. From this spreading mycelium of transversely septated hyphe in Penicillium arise hyphe which branch at the extremity into a number of erect branches from the ends of which are cut off in sequence a series of small round cells, the spores, which if undisturbed remain connected in a chain, so that the fructification roughly resembles a small broom, or whisk. The large vertical hypha is a conidiophore, and as the spores are pinched, or abstricted off from the secondary branches as single cells, they are known as conidiospores (xévis, dust + oropa a seed) (Fig. 14 and Figs. 243 to 263 inclusive). The third example, which we will use to describe in general terms the vegetative organs of the fungi, is the honey-colored toadstool, Armillaria mellea (Fig.15). The toadstools, or fruit bodies, often form ———- Fic. 14.—Con- idiophores of com- mon green-mould, Penicillium glau- cum with terminal chains of conidio- spores. (After Conn, Agricultural Bacte- riology, p. 7.) dense clumps around the base of some dead or dying tree, or almost cover an old stump on which they grow. The cap is of a honey-colored brown, about two inches across, and the stem may be six inches long and paler than the cap. Microscopic sections of the stem and cap show that they consist of hyphe that are closely bound together to form the stem and cap. If we examine the base of the stalk, we find that it arises from a dark-colored cord-like strand which has been termed a rhizomorph because of its resemblance to a root (Fig. 15, Il and IV). These rhizomorphs constitute the mycelium and they either ramify through the soil, or else are found beneath the bark of the dead tree, where they unite to form open-meshed nets of a dark brown color. These rhizomorphs are strands of hyphe that run longitudinally. The hyphal cells are bound together in a cord-like cable which is peculiar in that it shows apical growth, constantly elongating at its extremity, as it grows beneath the bark, or penetrates the soil (Fig. 15) CHARACTERISTICS OF THE TRUE FUNGI 47 kh COR SEY TERS Wiss = ez S ey, fey sl OTS op aN =e KER Fic. 15.—Details of the mycelium of Armillaria mellea. I, Piece of mycelium on slide; II, piece of old mycelium (Rhizomorpha subterranea); III, rhizomorph pro- ducing fruit bodies; IV, apex of rhizomorph capable of growth; (a) peripheral hyphae; (b) pseudo-epidermis; (c) growing point; (d, e, h) pith; (#) hollow center. (J and IV after Brefeld; III, after Hartig in Zopf, Die Pilze, 1890, p. 25.) 48 MYCOLOGY its extremity, as it grows beneath the bark, or penetrates the soil (Fig. 15). Such a compound thallus differs strikingly from the filamentous thalluses of the two previously described fungi. The union of the hyphal cells in some of these fleshy fungi may be so intimate as to con- stitute a pseudoparenchyma, and this close union of the cells may be made still more intimate by clamp connections where two adjoining cells are bound together endwise by a clamp-like protuberance of one of the cells attached to the end of the other adjoining cell. When the pseudo- parenchyma is external, it may serve for the protection of the internally disposed hyphe, and be looked upon as protective tissue. Mechanic tissues for the support of fungi are not unknown in some of the groups, as in some of the polypori; where there are clamp connections, trans- verse septa and thickened cell walls. A few of the higher fleshy fungi have conducting hyphe, which are larger and more tubular than the surrounding hyphe, and which conduct later, oil and other substances. Those which conduct a milky juice, as in some species of Russula and Lactarius, may be termed laticiferous hyphe. There are some fungi in which the hyphal form of thallus is not present. The yeasts are either single ellipsoidal cells, or these cells are loosely connected together in a chain of bed-like cells. These chains are due to the budding or sprouting method of cell multiplication where a bud, gemma, or sprout, grows out from the mother cell as a daughter cell. It in turn buds producing a granddaughter cell and so forth. Such a method of reproduction is known as gemmation. In the parasitic fungi, the hyphe run either into the cells, through the cells (intracellular), or between the cells (intercellular).. Where the hyphe are intercellular, short branches may be formed which penetrate the host cells. These short branches take various forms and are known as haustoria; a single one as an haustorium (Figs. 36 and 67). Occasionally in the mildews, the mycelium may be superficial and hence epiphytic, while the mycelia which are internal are endophytic. These are useful terms when describing the parasitic habits of fungi. Some of the groups of fungi have mycelia that form resting bodies of hyphe. These are the most compact of all forms of mycelia and are known as sclerotes (sclerotium—ia), which in many cases assume tuberous forms. They are resting states of the mycelia and act as stores of reserve material. These are some of the principal forms of the vegetative thallus of the fungi. Further details will be given in he discussion which follows. Some sudden epidemics of rust fungi CHARACTERISTICS OF THE TRUE FUNGI 49 have been ascribed by Eriksson to the presence of the protoplasm of the rust mixed with the protoplasm of the host. To this included fungous protoplasm he gave the name mycoplasm. Some fungi are symbiotic, that is, they are found in intimate re- lation with chlorophyll-containing plants and obtain from them food of a carbonaceous character, but without apparently injuring the green symbiont. When they live with alge, they commonly form lichens; or if in connection with the roots of trees, orchids; and in prothallia they form what is known as mycorhiza (Fig. 16). The spores or reproductive cells of fungi may be of two kinds: non-sexual spores and sexual spores. The non-sexual spores are cells which are formed vegetatively. They are cells which take special Fic. 16.—Ectotrophic mycorhizas. At left hyphal mantle on root of hickory Carya ovata in cross section; at right root tip of an oak, Quercus, with fungous mantle. (From Gager, after W. B. McDougall.) forms in the different groups of fungi and are produced as special cells. in a purely vegetative manner. They represent a special part of the thallus given over, to reproduction. Upon the formation of these spores, which may germinate at once or live for some time as resting spores, the rapid multiplication of the fungi depends. It is the innu- merable quantity of these non-sexual spores upon which an epidemic of some particular fungous disease may depend. Only the most general characters of the various kinds of spores can be discussed in an intro- duction of this kind. The special kinds will receive due attention as we proceed. Spores which are cut off, or pinched off, in concatenation from the end of a vertical hypha, are known as conidiospores. In the rusts such conidiospores become wredospores, and in the mushrooms basidiospores. Where the non-sexual spores are formed in a spore case, 4 50 MYCOLOGY or sporangium, they may be termed sporangiospores (Fig. 13,f). Fre- quently spores are formed bya modification of certain cells of the hyphal branch. ‘These spores are usually thick-walled, as in the smuts, and become known as chlamydospores. Where the whole hypha is divided up into a chain.of spores one after the other in close order, such spores are called ozdiospores. Special receptacles are associated with the formation of the non-sexual spores. These are found in the sac fungi, ASCOMYCETALES, where the depressed conceptacle becomes a pycnidium, or conidial fruit, and the spores which it contains are pycnidiospores, pycnospores, pycnoconidia or the stylospores of Tulasne. This form of conidial fruit is surrounded by a firm wall or peridium. The pycnidia may be depressed in the tissues of a host plant or elevated above its surface, as the case may be. In some fungi the conidiophores, in- stead of being separate, are arranged in parallel order, side by side, at an early stage, and thus are united into a fascicle to which the name coremium has been applied. The principal sexually produced spores in the fungi are sygos pores, oospores, and ascospores. The first two forms are found in the sub- class PHYCOMYCETES. Their formation proceeds in such a manner that the zygospores are produced isogamously, that is, by the union of two similar cells, while the oospores are heterogamous, that is, they are‘ produced by a union of an egg cell and a sperm cell. Hence, we distinguish two orders of the PHYCOMYCETES, namely, the ZYGOMYCETALES and the OOMYCETALES, the first showing isogamy and the latter heterogamy. Details will be given when these orders are considered in detail: Until recently, it was believed that sexuality did not exist in the sac fungi, ASCOMYCETALES, but recent research has shown that the nuclei of two adjoining cells unite and this is followed by the formation of a spore sac, or ascus, containing sac spores, or ascospores. The formation of the asci is usually associated with the production of definite fruit bodies. It is doubtful whether sexuality is found in any of the other groups of fungi. Curious nuclear fusions in the rusts have been sug- gested as a sexual union, but it is safer to await future discoveries before adopting such a position. However, there are fungi in which sexual organs seem to be lost entirely and many of these belong to the most highly developed forms where the thallus and fructifications are of a complex type. The whole trend of evolution in the fungi is for CHARACTERISTICS OF THE TRUE FUNGI 51 the reduction in size and importance of the sexual organs, until they have disappeared completely. This may be a result of the perfect manner in which the different specific types are reproduced and multi- plied by the various kinds of non-sexual spores found in the different fungous groups. CHAPTER: V1 HISTOLOGY AND CHEMISTRY OF FUNGI Histology—Naked cells which are destitute of a cell wall and con- sist of naked protoplasm occur as motile cells in only two unimportant groups of the OOMYCETALES. The cell wall of fungi does not appear from the results of numerous workers upon its chemistry to be of the same nature in the different groups of them. A general term which has been in current use and which was first suggested by A. de Bary is that of fungous. cellulose, but that term, as far as indicating the chemic character of the membrane is concerned, is a misnomer. It has its correct application, if we employ the term in the sense of fungous membrane substance. We owe to C. van Wis- selingh (1898) the examination of about a hundred species from nearly all of the orders and most of the families of EUMYCETES. Wisselingh could detect the presence of cellulose with certainty only in two families, the SAPROLEGNIACE and the PERONOSPORACEH. ‘This carbohydrate could not be detected either in the ZYGOMYCETALES or in any of the MYCOMYCETES examined, and especially was it found to be absent in the yeast Saccharomyces cerevisie. The researches of Winterstein, Gilson and Wisselingh proved that chitin formerly sup- posed to be of animal origin was found in the membranes of fungi. With the exception of the two families mentioned above, the bacteria and the yeasts, chitin has been detected in all other species of fungi examined, e.g., Mucor mucedo, M. racemosus, Rhizopus nigricans, Penicillium glaucum, Trichothecium roseum, in the sclerotia of Botrytis cinerea and Claviceps purpurea. We do not know at present of the simultaneous occurrence of cellulose and chitin in the same cell wall. E. Winterstein has found true hemicellulose in certain fungi and other chemic substances have been reported such as carbohydrates of the pentosan group, pectose, callose, etc. g The outer layers of the wall, in some fungi (TREMELLACEH) may be mucilaginous, so that it is resolved into a soft gelatinous mass. Lignifi- cation has been reported in the large pileated fungi though whether 52 HISTOLOGY AND CHEMISTRY OF FUNGI Sat Ww the presence of lignin is proved thereby must remain an open ques- tion. Deposits and incrustations of calcium oxalate crystals are found in the membranes of fungi, as the spicules in the sporangial wall of Mucor mucedo. The cell contents, or protoplasm, of fungi may be divided into cytoplasm with its inclusions and nucleoplasm. The cells contain either a single nucleus (Erysiphe), two, as in Exoascus, or several, as in the mycelial cells of Penicillium glaucum and Peziza convexula. The hyphe of many contain numerous, sometimes over hundreds of nuclei (PHYCOMYCETES). The structure of the nucleus in basidia as described by Wager agrees with that of the higher flowering plants. It has a nuclear membrane, nucleolus and nuclear network of threads coiled in a loose knot. , Chromatin granules occur. The nucleus undergoes division either by fission, or by karyokinesis, as first observed by Sadebeck. Chromosomes are formed from the chromatin bodies when the nucleus begins to divide. A reduction of chromosomes has been observed by Stevens. Fats and oils are present in fungous cells and are found in the form of drops or globules. Glycogen has been de- tected in the spore sacs of the ASCOMYCETALES. Volutin is a name given by Meyer to a reserve substance which contained C,H,O,N and P atoms. Mannite, trehalose and glucose have been found in many fungi by Bourquelot. Special substances of a poisonous nature such as ergotin, muscarin, phallin are of special significance in cer- tain fungi. Colors.—Full details regarding the coloring matters in fungi will be found in Zopf’s “Die Pilze in morphologischer, physiologischer, biologischer und systematischer Beziehung,” 1890. Clear bright colors are present in such species as Peziza aurantia, P. coccinea. Russula virescens, has a cap with shade of green lighter, or darker, in individual specimens. Russula emetica is red. Blue is the predominat- ing color in the genus Leptonia. Armillaria mellea has a honey- brown, or yellow color. The violet color of Cortinarius violaceus is well known. The color in a number of fleshy fungi changes when the fruit bodies are broken, injured or exposed to the air. This change of color is due to an oxidizing enzyme. ‘The flesh of a number of species of Boletus changes from white or yellow to a deep indigo-blue when broken, or abraded. The deliquescence of species of the genus Coprinus, when the color changes from white to black with the melting 54 MYCOLOGY down of the whole fruit body has been proved to be a process of auto- digestion. When the hyphe are colored, the color is confined generally to the cell wall, although Biffen states that in some hyphe the color is located in the contents, the wall remaining colorless. Spores are colored frequently as in Ascobolus which grows on manure. The spores at first colorless change through pale lilac to clear deep amethyst. The coloring matter is confined to the spore walls, but in some cases the contents are colored, while the wall is colorless, as in many eciospores. PHYSIOLOGY OF FUNGI The research of recent years in the nutrition of fungi has shown that nine chemic elements are necessary for the structure and complete development of the true fungi. These elements are carbon, hydrogen, oxygen, nitrogen, sulphur, phosphorus, potassium (or rubidium), magnesium and iron. Analysis of the ash constituents of fungi shows that phosphoric acid and potassium are the chief ones, the latter form- ing seldom less than one-quarter and sometimes one-half of the total. Phosphorus is present in the ash to the extent of 15 to 60 per cent. and is eagerly absorbed by growing fungi, as is shown by Dedalea quercina, which in its growth completely extracted the phosphoric acid from decayed wood. Winogradsky, Meyer, H. Molisch and W. -Benecke have shown that magnesium is indispensable to fungi. Be- necke has demonstrated a considerable difference in development shown by two, otherwise equal, specimens, the one grown without magnesium and the other in a medium containing 0.0025 mg. of crystallized magnes- ium sulphate per 25 c.c. and Guenther has proved that 0.005 mg. of magnesium sulphate was necessary to induce a sowing of Rhizopus nigricans to grow at all. As to iron, as an indispensable element before the matter was put to the test, it was thought that fungi being chlorophylless did not require iron like the green plants in which iron was concerned in the formation of chlorophyll. The experiments of Hans Molisch tend to prove the essential importance of iron in the nutrition of the true fungi for in presumably iron-free cultures, the spores of Aspergillus niger did not develop beyond the formation of a sickly mycelium. Similar results were obtained with sowings of pressed yeast cells, spores of Mucor racemosus and a species of Penicillum. Iron in addition to HISTOLOGY AND CHEMISTRY OF FUNGI 55 being a nutritive material also acts as a stimulant. The position of sulphur, as an important nutritive element, is doubtful. It is inferred that because this element forms an important constituent of the albu- minoids, that it is, therefore, essential to fungi, but there,are no re- liable experiments which prove that to be so. Awaiting more detailed investigations, sulphur has been included in the above list of nutri- tive elements. The source of the C, H, and O which form such an important part of the food of fungi is the dead or living bodies of other plants and animals, principally. plants in which are found sugars, starch, cellulose, mannite, citric acid, and other bodies of organic origin. The source of nitrogen is similarly from soluble nitrogenous bodies, peptones, propylamin, asparagin and others, but few if any of the higher fungi can utilize free atmospheric nitrogen, as can the bacteria which form the nodules on the roots of leguminous plants, described in a former section of this book. The various culture media on which bacteriologists and mycologists cultivate successfully a large series of bacteria and fungi will be considered in a subsequent chapter. Modern research along the lines of technique has demonstrated many im- portant points about the growth and autrition of the higher fungi and these will be discussed, as we proceed to the end of the book. The chemic investigation of the fungi began with the refinements in the technique of modern organic chemistry and much has been pub- lished on the subject, so that there is a bibliography too voluminous to give. Much of the most important chemic work on fungi published prior to 1890 will be found in Zopf’s “Handbook.” No generai work of this kind has recently appeared, so that we must depend on recent original papers on the chemistry of fungi, and in part on the statements of Zopf’s great book. The following inorganic elements have been found in fungi: chlorine, sulphur, phosphorus, silicon, potassium, sodium, lithium, calcium, magnesium, aluminium, manganese and iron. Manganese has been found in the cap of Lactarius piperatus. Aluminium has been reported as occurring in the ash of lichens. The mean of a number of analyses! of mushroom (Agaricus campestris), truffle (Tuber), Morchella esculenta, two other species of Morchella, species of Boletus, and Polyporus officinalis is as follows: potassium 45 per cent., phosphoric acid 40 per cent., magnesia 2 per cent., sodium 1.4 per cent., calclum 1.5 per cent., iron oxide 1 per cent., silicic acid 1Zopr, WILHELM: Die Pilze: 118. 6 MYCOLOGY Un r per cent., sulphuric acid 8 per cent., chlorine 1 per cent. The organic compounds of the carbohydrate group found in fungi are cellulose, grape sugar, glycogen and kinds of gums, mannit, inosit, and several other less important ones. The organic acids include oxalic, malic, acetic, citric, formic, lactic, helvellic, and propionic acid, as well as other less well-known acids. Fats and oils are often present as reserve substance in many repro- ductive spores, as in oospores, zygospores, ascospores, and the like. Large quantities are also often present in the mycelium, as in Lactarius deliciosus, which contain 6 per cent. (5.86 per cent.). Fat is, as a rule, not entirely absent from any species of fungus. Fliickiger gives the fat content of the sclerotium of Claviceps purpurea as 35 per cent. The mushroom A garicus campestris has 0.18 per cent. and Helvella esculenta 1.65 per cent. ; Resin occurs in fungi in the form of excretions, partly as infiltra- tion of the cell walls, partly as contents of the living cells. The intense orange-yellow color of the caps and stipe of the Agaricus (Pholiota) spectabilis, according to Zopf, as also the pale yellow of the gills and the flesh of cap and stipe together with the ochre-yellow color of the masses of spores is due to the presence of a resin acid which is present as a hyphal cell content. Pigments of various kinds classified by Zopf are also found. Besides the important substances mentioned above, chemists have found coniferin, muscarin, trimethylamin (spores of Tilletia caries), ergotin, cholin, phallin, cholesterin. Several of these will be discussed in connection with the poisonous or non-poisonous character of certain of the fleshy fungi. ENzyMES (€vfuuos, leavened, from €v, in and (vyn, leaven, a term first suggested by Kiihne for an unorganized ferment).—The study of the ferments, or enzymes, of the fungi and higher plants has thrown a flood of light upon their metabolic activity, for enzyme action is the strategic center of vital activity. Pasteur emphasized the role of micro- 6rganisms as ferment producers, and that led to the classification of ferments into organized and unorganized. Since Buchner discovered zymase, ferments have been divided into endocellular and extracellular. Endocellular enzymes as those which cannot diffuse out of the cell, such as zymase, while extracellular enzymes are those which are capable of diffusion out of the cell, such as invertase. Hepburn defines an enzyme as a soluble organic compound of biologic origin functioning HISTOLOGY AND CHEMISTRY OF FUNGI wi as a thermolabile catalyst in solution. In connection with this defini- tion, it is important to know that a catalytic agent is one which alters the rate of a reaction without itself entering into the final product (Ostwald, 1902), or which does not appear to take any immediate part in the reaction, remains unaltered at the end of the reaction and can be recovered again from the reaction product unaltered in quantity and quality. Enzymes differ from ordinary inorganic catalysts in their sensitive- ness to heat and light. They are destroyed at 1too° C., and most of them cannot be heated safely above 60° C.! The velocity of the reaction increases with a rise of temperature up to an optimum and as the temperature is increased above the optimum the enzyme is permanently inactivated. Enzymes retain activity even after ex- posure to action of liquid air. Light-in its ordinary form in the pres- ence of oxygen and ultraviolet light independent of oxygen are de- structive to enzymes. Again, enzymes possess most of the important properties of colloidal solutions, such as their non-diffusibility. They are soluble in water, in dilute salt solutions, or in glycerin. They exhibit the phenomenon of adsorption. An important discovery has recently been made which has thrown considerable light on the activity of enzymes, and that has been the stimulation exercised by certain substances which have been called activators and the inhibition exercised by other substances, which have been called paralyzers. The activators are in some cases simple chem- ical substances, such as acids, alkalis and salts, or they are complex bodies of unknown chemic character, but they have this in common that they can be separated from the enzyme by dialysis, and are not de- stroyed by heating. An enzyme may be rendered inactive by the removal of its activator, but it can be restored to activity by mixing again with this substance. In the case of some enzymes, the inactive substance, as it is formed in a cell may be called a zymogen, or profer- ment, but when associated with the activator the active enzyme is developed. An activator is inorganic. A kinase is a more or less complex organic body which activates a proferment. Substances which reduce, or destroy, the activity of enzymes are called paralyzers, which may be formed as products of enzymatic 1 Haas, PAuL, and Hitz, T. G.: An Introduction to the Chemistry of Plant Products, 1913: 340-341. 58 MYCOLOGY activity or be foreign substances. Acetic and lactic acids formed by enzyme activity will destroy the ferments producing them unless neutralized. Among foreign substances which act as paralyzers may be mentioned formaldehyde, mercuric chloride, alcohol, chloro- form and hydrocyanic acid. Anti-enzymes are a class of substances, which are antagonistic to the action of enzymes. ‘The distribution of the enzymes in the various groups of fungi including the slime moulds, bacteria and true fungi have been investigated by a number of zymolo- gists. For example, Monilia sitophila may form maltase, trehalase, raffinase, invertase, cytase, diastase, lipase, tyrosinase and trypsin. Dox! has demonstrated in moulds, the following: protease, nuclease, amidase, lipase, emulsin, amylase, inulase, raffinase, sucrase, maltase, lactase, histozyme, catalase and phytase, and he has found that these enzymes are formed regardless of the chemic character of the substratum. Without going into all the details of the occurrence of énzymes in the fungi, the following classification of the principal enzymes found in the various groups may prove useful to the student. CLASSIFICATION OF ENZYMES IN FUNGI 1. HYDROLYTIC ENZYMES. (a) CARBOHYDRATE-SPLITTING ENZYMES (CARBOHYDRASES): Amylase, or Diastase, which hydrolyzes starch to dextrin and maltose. The Koji fungus, Aspergillus oryzee (Taka-diastase). Cytase, which hydrolyzes hemicellulose to galactose and mannose in Botrytis. Inulase, which hydrolyzes inulin to levulose. Invertase, which hydrolyzes cane sugar to dextrose and levulose. Saccharomyces, Fusarium, Aspergillus niger. Lactase, which hydrolyzes lactose (milk sugar) to dextrose and galactose. Kephir organism. Maltase, which hydrolyzes maltose (malt sugar) to dextrose. Saccharomyces octosporus. Raffinase, which hydrolyzes raffinose to levulose and melitiose. Aspergillus niger. Trehalase, decomposing trehalose into a reducing sugar. Poly- porus sulphureus. ' Dox, A. W.: Enzyme Studies of Lower Fungi. Plant World, 15: 40, February IQ12. : HISTOLOGY AND CHEMISTRY OF FUNGI 59 (6) PROTEIN-SPLITTING ENZYMES (PROTEASES): Pepsin, which hydrolyzes proteins to albumoses and peptones. Trypsin, which hydrolyzes proteins to peptides and amino- acids in Amanita muscaria and Boletus edulis. (c) UREA-SPLITTING ENZYMES (UREASES): Urease obtained from Micrococcus uree, which hydrolyzes urea into ammonia and carbon dioxide. (2d) NucLEAsE, which splits nucleic acid. (e) FAT-SPLITTING ENZYMES (ESTERASES and LIPASES): Lipase in Penicillium glaucum and Aspergillus niger, also Empusa. Phycomyces, which break up fatty oils. (f) GLUCOSIDE-SPLITTING ENZYMES: Emulsin, which hydrolyzes amygdalin to glucose, hydrocyanic acid and benzaldehyde. Also such other glucosides as salicin, populin, coniferin which fungi are able to utilize. 2. FERMENTING ENZYMES. (a) Alcoholic fermentation of glucose, levulose, mannose, etc., by zymase in yeasts. (b) Lactic acid fermentation of lactose by lactic acid bacteria. (c) Butyric fermentation of lactose by the butyric acid bacteria. 3. CLottinc Enzymes (Coagulation, Curdling). Rennin (Chymosin), which curdles milk. Bacillus mesentericus vulgatus. 4. OXIDIZING ENZYMES. (a) OxmpasEs, which oxidize alcohols to acids, e.g., the action of Mycoderma aceti, etc. (0) Tyrostnasr. Russula nigricans and species of Boletus, Lacta- rius, etc. (c) PEROXIDASES, which set free oxygen from hydrogen peroxide, causing this substance to blue guaiacum resin. (d) CATALASE, which decomposes hydrogen peroxide with the evolution of molecular oxygen. In concluding this brief study of the enzymes it may be stated that they can be detected by chemic, bacteriologic, serologic and histologic 60 MYCOLOGY means. Details of the occurrence of the above enzymes will be found in the books noted in the footnote below.' CHEMOTAXIS The attraction or repulsion of motile microdrganisms by chemical stimulants known as chemotaxis is found in the activity of the zoospores of the OOMYCETALES and in the growth of the hyphe of fungi in gen- eral toward or away from the stimulus. To these phenomena the names of positive and negative. chemotropism have been given. The thorough investigations of M. Miyoshi with Aspergillus niger, Mucor mucedo, Penicillium glaucum, Phycomyces nitens, Rhizopus nigricans have shown that the following substances act as powerful stimulants: ammonium phosphate, asparagin, dextrin, saccharose and glucose. The threshold value (marginal limit) or minimum quantity capable of producing a chemotactic effect was ascertained by Miyoshi as o.or per cent. in the case of glucose acting on Mucor mucedo. On gradually increasing the dose, a second limit is reached where repulsion occurs. The entrance of fungi into leaves and the growth of hyphe along certain lines inside of the host tissue and the formation of haustoria are per- haps all indications of chemotropic response. 1Bayuiss, W. M.: The Nature of Enzyme Action (Monograph on Biochem- istry). Longmans, Green & Co., ro1q. GREEN, J. Reynotps: The Soluble Ferments and Fermentation. Cambridge at the University Press, 1899. Haas, Paut and Hirt, T. G.: An Introduction to the Chemistry of Plant Prod- ucts. London, Longmans, Green & Co., 1913. Harpen, Artuur: Alcoholic Fermentation (Monograph on Biochemistry). London, Longmans, Green & Co., 1914. : LAFAR, FRANZ, TRANSL. BY SALTER, CHARLES, T. C.: Technical Mycology, ii, IPie, Th 8 (OU =OE. MAarsHALL, CHARLES E. and others: Microbiology. Philadelphia, P. Blakiston’s Son & Co., tort OPPENHEIMER, CARL: Die Fermente und ihre Wirkungen. Leipzig, 1903. VerNoN, H. M. Intracellular Enzymes. London, John Murray, 1908. CHAPTER VII GENERAL PHYSIOLOGY OF FUNGI The influence of light on the development of the KUMYCETES has been investigated by a number of workers. The influence of light on the direction of growth is known as phototropism. On account of the contradictory evidence of earlier investigations, Friedr. Oltmanns experimented with Phycomyces nitens using a powerful electric arc light. He found that Phycomyces behaved positively phototropic under weak illumination, but negatively so under a powerful light. It remained aphototropic with an intermediate illumination, and in young sporangial hyphe with gray sporangia, a given degree of illumination caused attraction, while with older sporangiophores with blackened sporangia repulsion was noticed. The germination of the spores of such fungi, as Penicillium glaucum, Trichothecium roseum, Fusarium heterosporium, Rhizopus nigricans, does not seem to be affected by light; while von Wettstein found that light retarded the germination of the spores of Rhodomyces Kochii. The evidence as to the influence of light on the vegetative development seems to be contradictory. J. Schmitz found that Spheria carpophila grew better in the dark than in daylight. G. Winter found Peziza Fuckeliana to cease growth in the dark and the fungus perishes if light be long excluded. Mac Dougal! experimented with Coprinus stercorarius. He found that it developed a much greater length than the normal in darkness, but the fruit bodies remained in a rudimentary or incomplete stage. After growth had proceeded in this manner for some time the illumination of the body was followed by the production of fruit bodies in a manner demonstrating most conclusively that the action in question was due to a purely stimula- tive action of light, since the rays did not participate in any synthesis of material. The rate of cell reproduction does not seem to be influenced by the presence or absence of light. In many fungi, the formation of a 1 Mac Doveat, D. T.: The Influence of Light and Darkness upon Growth and Development. Memoirs of the New York Botanical Garden, ii (1903: 270). Or 62 MYCOLOGY fructification does not seem to be affected by the light conditions, but here the evidence is contradictory, some fructifications being formed better in light than in the dark and vice versa. Kolkwitz after eliminating various sources of error of earlier experimenters found that in his cultures of Aspergillus niger and Oidium lactis that con- siderable acceleration of respiration is experienced with a brief illumina- tion by a powerful electric arc. Koernicke! finds that Roentgen rays inhibit the growth of fungi with prolonged action. Luminosity of Fungi.—The luminosity of wood and decaying logs in the forest is associated with the mycelia of certain fungi. The phenomenon is connected frequently with gill-bearing fungi, such as Agaricus, Armillaria mellea, Pleurotus olearius, and as determined by - Molisch with the two ascomycetous fungi. X yaria hypoxylon and X. Cooket. In order to prevent any error arising in the experiments through the presence of luminous bacteria, Molisch? grew Armillaria mellea, Xylaria hypoxylon, X. Cookei, Mycelium X. in pure cultures, the latter succeeding wellon bread. He found that under such con- ditions the plants became phosphorescent. Such phosphorescence is connected with a supply of oxygen and is not due to the separation of some luminous substances, but is intracellular in its origin. Liberation of Spores.-—The spores of the gill fungi (HY MENOMY- CETES) are very adhesive, when freshly set free. As a result of this, special arrangements are found for the liberation of the spores from the surfaces of the gills and the hymenial tubes. Paraphyses between the special conidiophores known as basidia serve to increase the spaces between the spores, preventing contact and allowing a freer fall of the spores. The arrangement of the gills is such as to economically increase the spore-bearing surface, and, therefore, the total number of spores that a fruit body can produce. By various growth movements of the cap and fruit stalk, the spore-bearing sur- face is placed in the best possible position for the liberation of spores. The spores liberated from the gills on the under surface of a pileus placed over a horizontal sheet of paper fall vertically downward and form a spore print, which consists of radiating lines corresponding to the inter-lamellar spaces. The number of spores set free by large fruit bodies is prodigious. A specimen of the mushroom Agaricus 1 KOERNICKE, Max: Ber. d. deutsch. Bot. Ges., 1904: 22, 148. 2? Moriscn, HAns: Leuchtende Pflanze, t904: 25-46. GENERAL PHYSIOLOGY OF FUNGI 63 (Psalliota) campestris with a diameter of 8 cm. produced 1,800,000,000 spores, one of Coprinus comatus 5,000,000,000 and one of Polyporus Squamosus 11,000,000,000 spores. Buller has estimated that a large fruit- body of the giant puffball Lycoperdon bovista (40 K 28 X 20 cm.) Fic. 17.—Diagram of the discharge of spores from a fruit-body of Polystictus versicolor as seen by a beam of light. A stream of spores is carried round within the beaker very slowly by convection currents and recorded. Reduced about 2/3. (After Buller: Researches on Fungi, 1909: 97.) contained 7,000,000,000,000 spores, Or aS many as 4000 mushrooms of the size above mentioned. Spores dropping from any fruit body which is suspended in a closed glass chamber can be seen in clouds, or individually, without the 64 MYCOLOGY microscope by concentrating a beam of light upon them (Fig. 17). This is a simple method of examining the discharge of spores from the mushroom. It can be used conveniently with the xerophytic fruit bodies of Lenzites betulina, Polystictus versicolor, Schizophyllum com- mune at any time in the laboratory by keeping them dry for months and reviving them by placing them in a jar with wet cotton. They quickly revive and begin to shed their spores in six hours and this discharge continues for some days. Ordinarily, spore discharge from any fruit body is a continuous process, but if placed in hydrogen, or carbon dioxide, the liberation of spores ceases quickly, demonstrating that oxygen is necessary. Ether and chloroform act similarly to the gases above mentioned. The X A '£B G 3 4 3 4 S e < , nm ' —— | , 1 2 & > x I ‘@ Fic. 18.—The successive and violent discharge of the four spores from the basid- ium of a mushroom Agaricus (Psalliota) campestris. X, The basidium with four ripe spores; A, B, C, D, successive stages of the discharge of spores I, 2, 3, 4 respec- tively. (After Buller, Researches on Fungi, 1909: 144.) special conidiophore, or basidium, usually bears four spores which are discharged successively, each spore being shot out violently by the pressure of the cell sap upon the wall of the basidium and perhaps also on the spore wall within a few seconds or minutes of one another (Fig. 18). The rate of the fall was observed by Buller, who used a horizontal microscope and a revolving drum to record accurately the rate of their fall. The rate of fall of the spores of gill fungi ranges from 0.3 to 6.0 mm. per second. It varies with the size, specific gravity and the progress of desiccation of the spores. Buller found the relatively small spores of Collybia dryophila in dry air to fall at an average rate of 0.37 mm. per second while the relatively large spores of A manitopsis vaginata in a saturated chamber attained a speed of 6.08 mm. per GENERAL PHYSIOLOGY OF FUNGI 65 second and the spores of the common mushroom shortly after leaving the cap fall at the rate of 1 mm. per second approximately. ' The violent discharge of the spores prevents the adhesive spores from massing together and from sticking fast to the gill surface. At first the spore is shot out horizontally, then under the influence of gravity, it describes a sharp curve and then falls vertically. The path described by the falling spore has been appropriately called a vy Fic. 19.—Amanitopsis vagineta. Relations of spores to the fruit-body. A, Transverse section through two gills, h, basidia projecting, the arrows show spore parts (sporabola), Magn. 15; B, vertical section of hymenium and subhymenium, c, paraphyses, a—c, basidia stages, Magn. 370; C, isolated basidium with two basidios- pores; D, discharged spore; EF, basidium, Mayer, 1110. (After Buller, 1909: 165.); sporabola (Fig. 19). There are two distinct types of fruit bodies as to_ spore production and spore liberation. These are the Coprinus comatus and the mushroom types. The deliquescence, or melting of the fruit bodies of the Coprini is a process of auto-digestion and it assists mechan- ically in the discharge of the spores. Spore discharge precedes deliques- cence. ‘The spores are set free from below upward and by auto-diges- tion those parts of the gills are removed from which the spores have 5 66 MYCOLOGY been shed, thus permitting the opening out of the cap and the freer discharge of the remaining spores. ‘The discharged spores are conveyed by the wind (Fig. 20). The mushroom type is the usual kind where the spores are discharged without deliquescence. The spores of Bulgaria, Gyromitra, Peziza and others of the ASCOMYCETALES are scattered by the wind, but those of Ascobolus immersus and Saccobolus are dispersed by herbivores. The spores of Peziza repanda, according to Buller, are shot up into the air to a height of 2 to 3 cm. and leave the spore sac (ascus) together, but \ M | f fi 4 | A VA Ki Fic. 20.—Semidiagrammatic sketch in a field with horse mushroom, Agaricus @saliiotay 2 ee ) arvensis, showing liberation and discharge of spores horizontally and from velum. Reduced to 14. (After Buller, Researches on Fungi, 1909: 218.) separate as they leave the ascus mouth. Puffing is due probably to a stimulus given, to the protoplasm in contact with the ascus lid, and it is observed when poisonous substances are applied such as iodine mercuric chloride, silver nitrate, copper sulphate, sulphuric and acetic acids are used. With some of these forms the ascus may be considered as a squirting apparatus by which a jet of spores leaves its mouth. The writer‘ noted the puffing of the spores in Peziza badia when the large saucer-shaped fruit bodies were held in the hand. At intervals of several minutes the puffing took place. Ascobolus immersus as a coprophilous (dung-inhabiting) fungus has 1 HARSHBERGER, J. W.: Journ. of Mycol., 8: 158, October, 1902. GENERAL PHYSIOLOGY OF FUNGI 67 special adaptations: (1) the protrusion of the ripeasci beyond the general surface of the fruit body; (2) the diurnal periodicity in the ripening of successive groups of asci; (3) the positive heliotropism of the asci; (4) the considerable distance to which the spores are ejected (sometimes 30 cm.) with which is associated; (5) the large size of the asci and spores; and (6) the clinging of the eight spores together, while describing their trajectory through the air. The forcible explosion of the sporangio- phore of Pilobolus crystallinus by which the whole sporangium is dis- charged a considerable distance into the air is due to the tension exerted by gases and water vapor within the swollen sporangiophore. The escape of biciliate zoospores (swarm spores) in such genera of aquatic fungi as Achlya and Saprolegnia is through a terminal pore in the zoosporangium. It appears that the discharge is associated with the motility of the cilia. In the moulds (Mucoracre2), the sporangial wall which is coated with minute particles of calcium oxalate becomes soluble in water at maturity and the intersporal substance swells up assisting in the liberation of the spores. The entire inner peridium about the size of a pin’s head is forcibly ejected in the gasteromycetous fungus, Spherobolus stellatus, and this is due to the unequal tension of the different peridial layers. The disposal of spores and conidia is facilitated by water in the case of the motile zoospores of such fungi as Achlya prolifera, Phytoph- thora infestans and Saprolegnia ferax, where cilia come into play. Many spores are no doubt carried passively by water currents. Wind is, however, one of the chief agents in the distribution of fungous spores, such as those of the puffballs, the rusts and the moulds, although the distance that such spores are carried is probably exaggerated. Flies, which feed upon the strong-smelling slime in which the minute spores of such fleshy fungi as Mutinus caninus, Icthyphallus impudicus are imbedded, assist in the carriage of such spores and those of ergot (Claviceps purpurea) in the Sphacelia stage, where viscid drops exude that are attractive to flies, and although some flies arekilled by it, yet sufficient escape to carry the spores. Slugs and snails by crawling alternately over diseased and healthy plants, probably disseminate spores. That birds serve as distributors of spores is indicated by the studies of Heald with the chestnut blight fungus, Endothia parasitica, in which he found that a single downy woodpecker carried as many as 657,000 pycnospores. Certain subterranean fungi such as truffles are 68 MYCOLOGY eaten by rodents attracted by the strong smell that they possess and probably the mammal is instrumental in the spread of the spores. Many of the coprophilous fungi have spores which pass through the alimentary canals of different animals without being destroyed and germinating in the dung, or manure from such animals, they propagate thespecies. Pilobolus crystallinus is one of them. The sporangia, which are shot off from the sporangiophore, adhere to blades of grass, which are eaten by horses, and later the fungus makes its appearance on horse manure. ‘The spores have passed through the horse apparently unaf- fected and more readily germinable. Man with his agricultural imple- ments is concerned with the spread of fungous spores. Giissow states that a threshing machine, which has been used for threshing smutted wheat, is infested so fully with spores that any grain subsequently threshed, unless the machine is sterilized properly after use, will become lable to infection. CHAPTER: VIII ECOLOGY OF FUNGI As fungi are either saprophytes or parasites, their life history is bound up with the substratum on which the saprophytes are found and with the host plant upon which the parasite lives, yet there-are many diverse forms of saprophytic fungi and the greatest variety of fungous parasites. Of special interest in connection with the ecology of fungi are the organs by which various fungi are tided over periods of drought, inclement seasons, or during the winter’s cold. These organs are compacted masses of hyphe of a rounded, globular, or ellipsoidal form ranging in size from those that are almost microscopic to those which are the size of a small canteloupe. These tuber-like masses of hyphe in a resting state are known as sclerotia (Gr. oyAupds, hard). They are found inagreat many fungi, ascommonly in the ergot, Claviceps pur- purea,and the lettuce drop, Sclerotinia libertiana, which forms sclerotia that may reach a length of 3 cm. in exceptional cases. These sclerotia are obtained readily in culture tubes with beerwort agar, or glucose agar, as culture media. From the sclerotium later arises the stalked fruit body, or apothecium. Cordyceps militaris is a fungus which attacks the larva of insects. Its mycelium penetrates the insect’s body and later in the Isaria form produces aerial hyphe which cut off conidio- spores. The growth of the mycelium is such as to penetrate to all parts of the larva filling it up as if it were stuffed with cotton. The mass of hyphe is converted into asclerotiuma nd the larval body is mummified, but still retaining its original external form. Later, the next spring, a stiff-stalked stroma arises with an enlarged extremity in which the perithecia with their asci- and ascospores are formed. Later the needle-shaped ascospores are set free and by cutting off conidio- spores reproduce the disease. Cordyceps (Torrubia) ophioglossoides is parasitic upon an underground truffle, Elaphomyces muricatus, Fig. 21). The stroma is erect, yellow and club-shaped at the extremity. Perithecia, asci- and ascospores are borne in the swollen part of the stroma. The fungus which discharges its spores above ground finds the 69 70 MYCOLOGY } if ante = aaaaine sea Ssneannere eon = if en marten ne {ngewe fe eee ee ee mest re rt Fic. 21.—A Cordyceps militaris; B, Cordyceps Hiigelii on a caterpillar; D, Cordy- ceps spherocephala on a wasp; E, Cordyceps cinerea on a beetle; F—K, Cordyceps ophioglossoides, F on a deer truffle; G, ascus; H, conidiophore; J, conidiospores; K, germinating spore. See Die natiirlichen Pflanzenfamilien I. 1, p. 368. ECOLOGY OF FUNGI 7fa underground truffle in the following manner. When the spores germi- nate, they give rise to hyphz which grow over a densely cespitose, com- mon moss, Mnium hornum, which develops a large number of feeding rhizoids, that penetrate the soil to the depth at which Elaphomyces grows. ‘The mycelium of Cordyceps not only covers the aerial portions of the moss, but follows the rhizoids underground until they reach the underground truffle over which the moss may happen to grow. Bot- anists searching for Elaphomyces always know where to look for it by the presence of the Cordyceps hyphe, on the moss Mnium hornum. There is a black beetle, a native of France! with a pale, velvety abdo- men, known as Bulboceras gallicus, about as large as a cherry stone. By rubbing the end of the abdomen against the edge of the wing cases it produces a gentle chirping sound. The male has a horn on his head. This insect burrows in the soil among the trees of the pine forests and is nocturnal in its habits. It descends vertically into the soil in search of the underground truffle-like fungus, Hydnocystis arenaria, upon which the insect rabassier feeds. The fungous fruit body is about the size of a cherry with a reddish exterior covered with shagreen-like warts. The beetle, which feeds upon Hydnocystis arenaria and Tuber Requenii one of the truffles, locates the fungi by a subtle sense of smell. The human truffle hunter finds these underground by the burrows which the beetles make in digging for their chief source of food and he usually finds groups of these fleshy funguses directly beneath the openings of the beetle holes. Rozites gongylophora is a gill fungus which is raised as a fodder by leaf-cutting ants in their subterranean passageways in the tropics of South Brazil. On a visit to the Berlin Botanical Garden in 1808, the writer noted the following remarkable examples of sclerotia-bearing fungi: Poly- porus sapurema A. Moller (Fig. 92, Teil I, Abt. 1**, Die naturlichen Pflanzenfamilien, p. 171). The sclerotium is over 30 cm. in diameter and weighs at least 20 kg. It is furrowed and roughened and leather colored. A specimen from Blumenau, Brazil, developed in the Victoria house of the Berlin Garden four large pilei in August and September, 1897. Polyporus mylitte found in Australia produces a sclerotium (Mylitta australis Fr.), which as “native bread’ is used as food by the natives. Polyporus tuberaster, which grows in the mountains 1 Fapre, F. H.: Social Life in the Insect World, 1912 217-237. 72 MYCOLOGY of Italy, develops a large edible sclerotium called by the natives pietra fungosa. The sclerotium of Polystictus socer (Fig. 94 A, Teil I, Abt. 1**, Die naturlichen Pflanzenfamilien, p. 177), known as Pachyma malacense, is of variable shape, 8 to ro cm. long, brownish red externally with a white interior. It is found in the Malay Archipelago. These are a few of the true sclerotia which probably includes the “tuckahoe”’ of the North American Indian, Pachyma cocos. Living on limbs, twigs and the leaves of the beech in the deep shade of the forest is found a scale insect (Schizonema imbricator),+ which is covered by a woolly coat consisting largely of a waxy secretion from the body. This woolly material is quite abundant and where the insects live in masses together the entire limb, or leaf surface has a downy white appearance. The abdomen of the insect moves con- stantly with a jerky motion and the cottony material is, therefore, constantly agitated. The insects secrete a honey dew so copiously that it runs down to the leaves beneath and to the ground. Upon this honey dew and the dead bodies of the scale insect, a pyrenomycetous fungus, Scorias spongiosa, lives. It grows as a spongy mycelium con- sisting of much-branched, rigid, septate hyphe with the strands glued together by a mucilage. Pyriform perithecia, long-necked spermogonia and pycnidia are formed from the mycelium, which is saprophytic on the products of the insect’s body. The anther smut of the caryophyllaceous flowers occurs in America and Europe on Cerastium viscosum, Saponaria officinalis and Silene inflata, and on species of Dianthus, Lychnis, Melandrium, Stellaria, etc. The spores of this smut replace the pollen grains in the anthers of these plants and when the flowers open a violet smut dust is dis- charged from the anthers instead of the pollen. Female flowers of Melandrium attacked by the fungus show a marked morphologic differentiation in the development of mature stamens out of staminal rudiments. These anthers are invaded by the fungus and in them the parasite fructifies. : The formation of galls is a marked feature of the ecology of fungi. One form of these malformations is seen in the witches’ broom (hexen besen) which are due to the attack of a number of species of Exoascus on different forest trees. The branchlets are clustered into broom-like masses with leaves that are somewhat altered in shape and fall earlier 1HARSHBERGER, J. W.: Journ. of Mycol., 8: 160, October, 1902. ECOLOGY OF FUNGI Va than those on normal twigs. Witches’ brooms are found on such conif- erous trees as the white cedar in New Jersey and are due to Gymno- Fic. 22.—Black knot of plum, Plowrightia morbosa, on beach plum, Prunus maritima Nantucket, August 17, I9QI5. sporangium Ellisii, a rust fungus. These malformations occur on the hackberry, but on this tree they are due to the attack of a mite Phy- toptus followed by a fungus. Plum pockets are a form of gall in which 74 MYCOLOGY the fruit is enlarged by the attack of the fungus at the expense of the stone which fails to develop. The hollow galls on the plum are due to Exoascus prunt. The so-called cedar apples on our red cedar trees in the spring are caused by the attack of an annual rust fungus, Gym- nosporangium juniperi-virginiana, and from the surface of these apples two-celled spores arise. The white rust of cruciferous plants, Cystopus candidus, produces blisters on the leaves and stems of shep- herd’s purse. The black knot of the plum is a tumor-like swelling of the branches of plum trees due to the attack of anascomycetous fungus, Plowrightia morbosa (Fig. 22). Large swellings on oak trees the size of a man’s head and over are caused by a fungus, Diachena strumosa, and some of these swellings may be the size of a large pumpkin. Galls due to insects are frequent on plants, but a discussion of them is extralimital. According to conditions of environment, we may briefly treat of fungi as hygrophytic, mesophytic and xerophytic forms. The hygro- phytic forms include the aquatic fungi, such as Achlya, Mono- blepharis, Saprolegnia and other genera which live and carry on their reproduction in water. Perhaps to this group would belong a fungus of the genus Cyttaria, which was found by Darwin in the beech (Nothofagus) forests of southern Patagonia. The beech trees grow in cold, wet valleys completely barricaded by great moulder- ing trunks of former beech trees on which the globular, bright yellow fructification occurs and which is eaten by the Fuegians. The mesophytic forms include many of the common fleshy gill fungi that live in our woods and forests, appearing in surprisingly great numbers after a spell of wet weather. Here we might include species of Amanita, Boletus, Russula, and Clavaria and others which are not infrequent, while in our meadows occur mushroom and coprini. ‘Three conditions seem favorable to their growth: abundant leaf mould, warmth and abundant moisture. The habitats of the fleshy fungi are of general interest. Collybia platyphylla develops its fruit bodies on the shaded side of decaying logs. The fairy-ring fungus, Marasmius oreades (Fig. 23) produces its sporophores in lawns in the form of rings long known as fairy rings. Frequently grassy spots are enclosed by the circle of toadstools which are several feet in diameter. The fruit bodies of Pholiota adiposa (Fig. 24) grow from wounds in living trees. In forest operations the slash, when scattered, rots more rapidly than when piled. This is due to the fact that two types of fungi ECOLOGY OF FUNGI 75 are active in rotting the brush, one set entering the limbs and branches above the ground and the other gaining access to the brush actually in contact with the soil. Brush is rotted at the top when piled with one group of fungi and at the bottom by another group, while the middle of the pile, not in contact with the soil and yet protected from the sunlight, apparently will not rot to any extent until the Fic. 23—Fairy ring formed by Marasmius oreades, an edible toadstool. (From Wiley, Foods and Their Adulteration. After Coville, Circular 13, Division of Botany.’ pile disintegrates sufficiently to expose these central layers to the soil moisture on the one hand, or to the sunlight on the other. Four fungi cause rotting of oak slash in Arkansas, viz., Stereum rameale, S. umbrinum, S. versiforme and S. fasciatum. Two fungi are responsible for the decay of short-leaf pine slash. They are Lenzites sepiaria and Polystictus abietinus.' The xerophytic forms are those which have corky or leathery fruit 1Z2ong, W. H.: Investigation of the Rotting of Slash in Arkansas. U.S. Dept. Agric. Bull. 496, Feb. 16, 1917; also Humphrey, C. J.: Timber Storage Conditions in the Eastern and Southern States with Reference to Decay Problems Bull, sro; -U. S. Dept. Agric., May 17, 1917. 76 MYCOLOGY bodies growing on sticks and logs where they can dry up without any loss of vitality. They revive after a rainfall and resume the function of discharging spores and the discharged spores are capable of germina- Fic. 24.—Pholiota adiposa growing from a wound in a living tree (edible). (After Patterson, Floraw and Charles, Vera K., Bull. 175, U. S, Dept. Agric., Apr..25, TOUS ie tion. Dedalea (Fig. 202), Polystictus and Stereum are typical genera of the xerophytic log flora. Buller! describes the fruit bodies of Schizophyl- lum commune as possessing special adaptations for a xerophytic mode of 1 BULLER, A. H. REGINALD: Researches on Fungi, 1909: 264. 77 ECOLOGY OF FUNGI \\\ it Fo as 2 a ees D Re oH) » \, ees I Wma . SSS NIN o Anns A and B, fruit-bodies seen C and D, two fruit-bodies seen from below and in section; about twice magnified; E, section through pileus in wet weather Fic. 25.—Schizophyllum commune, a xerophyte. from above growing on wood, natural size. showing gills split down their median planes; F, section of a dry pileus; E and F about 12 times natural size, (after Buller, Researches on Fungi, 1900: 114.) 78 MYCOLOGY existence (Fig. 25). “The gills are partially or completely divided down their median planes into two vertical plates. While desiccation is proceeding, the two plates of each of the longer and deeper gills bend apart and spread themselves over the shorter and shallower gills. When desiccation is complete, the whole hymenium is hidden from external view and the fruit body is covered both above and below with a layer of hairs (Fig. 25). The closing up of the fruit bodies at the beginning of a period of drought serves to protect the hymenium. A fruit body which retains its vitality even when dry for two years will revive again in a few hours and spores are discharged” (Fig. 25). As it is not the purpose of this book to consider the so-called lichens in the classification which follows as distinct entities in which the lichen fungus and the lichen alga are in symbiosis forming a lichen thallus, it is important to describe the ecology of the actual relationship of the two plants to each other, as a matter of botanic interest. Danilov, Elenkin, Peirce and Fink have shown that the dual hypothesis, or that of mutualistic symbiosis, is untenable. A lichen is a fungus belonging to the orders ASACOMYCETALES, or BASIDIO- MYCETALES, which lives during all or part of its life in parasitic relation with an algal host and also sustains a relation with an organic or an inorganic substratum. Having squarely assumed this position as to the true nature of what currently passes for a lichen, it is interest- ing to note that there are ten alge known as lichen hosts: Chlorococcum (Cystococcus) humicola, Palmella botryoides, Trentepohlia (Chroole pus) umbrina, Pleurococcus vulgaris, Dactylococcus infusionum, Nostoc lichen- oides (?), Rivularia nitida, Polycoccus punctiformis, Gleocapsa polyderma- tica and Sirosiphon pulvinatus. It is important to note, that although the larger number of the above are blue-green alge, yet the two species of green alge. Chlorococcum humicola and Trentepohlia umbrina form the hosts of many more lichens than all the others combined. Hence the student of these plants can study the algicolous fungi, mainly ASCOMYCETELES, a few BASIDIOMYCETALES, those parasitic upon alge, as the lichens, while the non-algicolous fungi can be over- looked by the lichenologists. We can do no better than quote Bruce Fink,! who sums up the main arguments against mutualism and the 1 Frnx, Bruce: The Nature and Classification of Lichens. I. Views and Argu- ments, Mycologia, iii: 231-269, September, rorr; II. The Lichen and its Algal Host, Mycologia, iv: 97-166, May, 1913. ECOLOGY OF FUNGI 79 advocation of the fungal nature of lichens, as follows: “‘Lichens com- monly grow where there are free alge of the. same species as those parasitized by these lichens. The spores of the lichens germinate and attack the free alga as other fungi attack their hosts. Lichens perform like other fungi on culture media and may be made to produce their reproductive organs on these media. Lichen spores also attack the algal hosts, when the spores and the alge are introduced into cultures together; and the resulting lichen is normal and sometimes fructifies in the cultures. Algal hosts extracted from lichen thalli grow in cul- tures like free alge of the same species grown on similar culture media. The researches of Elenkin and Danilov prove that lichen hyphe absorb food from the algal host cells, which are killed by severe parasitism, or more probably by parasitism and saprophytism combined. The relation of the lichen to its substratum proves that higher lichens can take comparatively little food from it and must depend more than lower lichens upon the algal hosts; and this shows that the parasitism of the lichen upon the algal host has become more severe in the evolution of the higher lichens. Finally, the alge para- sitized by lichens are in a disadvantageous position with reference to carbon assimilation. “Lichens are like other fungi with respect to vegetative structure and fruiting bodies. ‘The bridges which connect lichens with other fungi are not few, but many. Since it is thoroughly demonstrated that the lichen is parasitic, or partly parasitic and partly saprophytic on the alga, there is no longer even a poor excuse for a ‘consortium’ or an ‘individualism’ hypothesis. “The parasitism of lichens on alge is peculiar in that the unicellular or the filamentous hosts are enclosed usually by the parasite, which carry more or less food to the host. The host inside of the parasite is placed in a disadvantageous position with reference to carbon assimila- tion and may depend, for its carbon supply, more or less upon material brought from the substratum by the parasite. Some algal individuals, not yet parasitized, may be found in most lichen thalli.”’ Lichen thalli are of three kinds: crustaceous, foliose and fruticose. The arrangement of the layers of the lichen fungus and its algal host varies in different lichens, but in Sticta the following are met in a ver- tical section of the thallus (Fig. 26): (a) Tegumentary layer. MYCOLOGY 80 BCgi 8 a OUCr ens Spel) So tg goo 6 o 4 §es Sivan cies fs Ha, tol eyo S wet oe 3 ae eres EBS ORECS ah ees ctor ier ag hs a. a -8 23a S a.8 PUIG) See 24.08 3 9 ST & n ‘a 3 Buc 85 Rice ® o gw OS AGA S ve OSS S38 Gg BS sav (o) SS eee SSgius Mae oS 72a oc SiS a ta oS eee Bebe Se IS GS a5 (| feet =) Wome « ° S| Sn eel oh A BHOnOm amen S20 qo Se) Gee ae Gi os wh tS pels oh sos O wn eae om Soa | San 9 oO g's ? Sie siee ian am Siete q Ges Sino on jor Pi Spe Sas - “woe H ECOLOGY OF FUNGI SI (b) Upper cortical layer. (c) Algal layer (gonidial layer). (d) Medullary layer. (e) Lower cortical layer. The tegumentary layer consists of several rows of flattened hyphal cells extending at right angles to the underlying cortical cells which consisting of hyphal cells are pseudoparenchymatous, resembling the parenchyma tissue of higher plants. The algal layer contains the _ gonidia, or green plants, which act as hosts tothefungoushyphe. The medullary layer which is thicker than the others consists of much elongated hyphe forming a loosely interwoven tissue with large air spaces. The lower cortical layer is pseudoparenchymatous and from its lower surface rhizoids are developed. The apothecia and perithecia are the fruit bodies of the ascomycetous fungi which form the lichens. A vertical section through an apothecium of Sticta shows the following layers: (a) the epithecium, (6) the thecium consisting of the spore sacs (asci) and paraphyses, (c) the hypothecium or hyphal structure immediately below the thecium, (d) upper algal layer, (e) medullary layer, (f) lower algal layer, (g) cortical layer (Fig. 26). Some of the fruticose lichens have a central core-like strand of hyphe running through the medullary region which serves as supporting mechanic tissue as in Usnea barbata. The soredia are vegetative repro- ductive bodies consisting of from one to many alge surrounded by continuous hyphal tissue and are common upon the upper surface and margins of most of the higher lichen thalli. Among the BaAsip10- LICHENES basidia are formed with basidiospores on sterigmata as in Cora, Dictyonema, Laudatea. CHAPTER Ix FOSSIL FUNGI AND GEOGRAPHIC DISTRIBUTION Fungi in the Fossil State.—All the known fossil fungi numbering over 400 species have been figured and described by Meschinelli in his “Fungorum fossilium omnium Iconographia” published in 1808. Zeiller in discussing the chronologic sequence of the groups of fungi states that representatives of the families CHyTRIDEACEZ, MucoRA- cE and PERONOSPORACE have been found in the tissues of the higher plants preserved in rocks of lower Carboniferous and Permian ages. Many different plants extending from the Carboniferous period upward show various forms of the ASCOMYCETALES on leaves and in the tissues especially those of the stems. The fleshy fungi of the families AGARICACEZ and PoLypoRACE& have been found in deposits of tertiary age. Weiss has announced the discovery of a mycorrhiza in the root of a probable Lycopodiaceous plant of the lower Carbonif- erous strata. Where Polyporus and Lenzites occur, as in the brown coals, silicified woods occur which have been half destroyed by their mycelia. GEOGRAPHIC DISTRIBUTION OF FUNGI This important and interesting subject can be presented in the barest outline. The modern teaching of geography emphasizes home geog- raphy as a fundamental study. In following this suggestion in the investigation of the local fungi, it will be found that we must deal with distinct habitats, such as leaf mold, sandy soil, wet soil, decayed logs, tree stumps, living trees, living herbs and the like. The black mould, Rhizopus nigricans, is one of the commonest of fungi. It occurs on bread and other organic substrata, such as sweet potatoes, whenever the conditions are suitable for its growth. If horse manure is covered with a bell jar with wet paper inside, there develops first the gray mould, Mucor mucedo. This is accompanied or followed by Pilobolus 1SEWARD, A. C.: Fossil Plants, 1898: 207-222. ° Weiss, F. E.: A Mycorrhiza from the Lower Coal Measures. Annals of Botany, XVili: 255 with 2 plates. 82 FOSSIL FUNGI AND GEOGRAPHIC DISTRIBUTION 83 crystallinus, and this in turn by the white flecks of Oospora scabies. Coprinus stercorarius usually completes this series of coprophilous fungi generally found on horse dung. Sometimes the Mucor is para- sitized by Piptocephalis and sometimes by Chetocladium. Peziza coccinea is attached to dead twigs buried in the forest leaf mould, and as it rises to the surface, it develops a long stipe with a crimson-red saucer-shaped apothecium at its extremity. Russula emetica, R. virescens, species of Clavaria and Boletus are regularly found beneath deciduous trees growing out of the forest litter. The puffball, Sclero- derma vulgare, is found on the tops of old stumps in gregarious clusters. Polyporus sulphureus grows out of partly dead chestnut and oak trunks; while the hymenophores of Armillaria mellea are found clustered about the bases of trees beneath the bark of which the rhizomorphs will be found growing. A species of Hydnum was found a few feet above the ground on a beech tree and Fistulina hepatica attached to tree trunks, where the swollen base gradually blends with the straighter hole above. Amanita muscaria and A. phalloides grow in solitary splendor at the edges of woods and copses, while the habitat of the mushroom in open fields is quite distinctive. The earth-star, Geaster hygrometricus, grows more frequently in sandy soil, where it spreads out its peridial segments. The habitat of the local species of the lichen fungi is of interest. The brown-fruited cup cladonia, Cladonia pyxidata, grows on stumps and on the earth, while the scarlet-crested cladonia, Cladonia cristatella, is found on dead wood. The Iceland moss, Cetraria islandica, grows on the ground as also the reindeer-lichen, Cladonia rangiferina, in ex- tensive masses. Another earth-inhabiting form is Peltigera canina. The trunks of trees are marked by the presence of Parmelia perlata and the fruticose bearded lichen, Usnea barbata. Smooth bark appears covered with runic character traced by the fruit bodies of Graphis scripta. The rock-dwelling Jichens include Physcia parietina and the rock tripe (tripe de roche), Umbilicaria which grows on the outcrops of Octorara schists at the Gulph. The distribution of the chestnut blight fungus, Endothia parasitica, is of more than local interest, although the agitation to control it started near Philadelphia. _ Apparently the fungus was introduced from China, where it has been found recently, with nursery stock into Long Island. From the neighborhood of New York City, it spread northeast, 84 MYCOLOGY northwest, west and southwest.’ Now it is found in Connecticut, New York, throughout New Jersey, and as far west as the Alleghany mountains in Pennsylvania. In isolated areas, it occurs in Virginia and West Virginia, endangering the future of the chestnut tree in America (Fig. 27). Wherever the cultivation of the higher plants extends, the fungi peculiar to these plants will be found, as the wheat rust, Puccinia Fic. 27.—Map of the eastern United States showing distribution of chestnut blight disease in 1911. Horizontal lines indicate area with approximately all the trees dead; vertical lines approximate area where infection is complete; dots indicate advanced points of infection. (From Gager, after Metcalf, U. S. Farmers’ Bull. 467.) graminis, in Europe, America and Australia. The damping-off fungus, Pythium de Baryanum, which is death to seedlings, has been studied by German, English and American botanists, as a reference to the litera- ture will show. The downy mildew, of the grape, Plasmopara viticola, apparently of eastern American origin, is found now in Europe and California, where it has become a serious pest. The black knot, Plowrightia morbosa, was apparently at one time confined largely to the Atlantic seaboard and was particularly abundant in New England and New York. It has now spread across the northern 1 Cf. Stevens, Neil E.: Some Factors influencing the Prevalence of Endothia gyrosa. Bull. Torr. Bot. Club, 44 :127-144, March, 1917. FOSSIL FUNGI AND GEOGRAPHIC DISTRIBUTION 85 United States to the Pacific coast. Such diseases as the sooty mold of orange, Meliola camellia, and the brown rot of the lemon, Pythiacystis citriophthora, are confined to these last plants and to the regions where the citrus fruits grow. ‘The anthracnose of the sycamore, Gnomonia veneta, is parasitic upon the leaves and shoots of the sycamore or plane tree, Platanus occidentalis, causing its leaves to dry up, as if bitten by early frosts. It seems to be more prevalent in the bottom of valleys, where the plane tree grows along streams, as here we find cold-air drainage. Sometimes after the first crop of leaves is lost, a second crop appears. Wherever the sycamore grows, Guomonta may be ex- pected. The so-called fly-cholera fungus, Empusa musce@, is parasitic in flies and is present on these insects in Europe, even in the far north, in North America and South America (Argentina). The coprophilous fungus, Basidiobolus ranarum occurs on the dung of frogs in Europe and America. Taphrina cerulescens does not seem to be choice about its hosts, occurring as spots on the leaves of Quercus cerris, pubescens, sessiliflora in middle and southern Europe and on Quercus alba, aquatica, coccinea, laurifolia, rubra, velutina in North America. The hairy earth-tongue, Geoglossum hirsutum, is truly cosmopolitan, as it has been reported from all over Europe, North America, Java, Mauritius and Australia. The genus Cyttaria with eight ascospores in each ascus in- cludes six species. C. Darwinii and C. Berterii were discovered by Darwin in Patagonia. C.Gumnnii occurs in Tasmania and C. Harioti in Terra del Fuego. None of the species, therefore, are found outside of the southern hemisphere (Fig. 28). The genus Hypomvyces includes species which live parasitically, or saprophytically, on other fleshy fungi. H. ochraceus lives on species of Russula in Germany, England and North America; H. chrysospermus occurs on species of Boletus in Europe; H. aurantius on PoLypoRACcEA and THELEPHORACE# in Europe; H. lateritius on Lactarius in Europe and North America; H. violaceus with its tender small stroma and violet-colored fruit body lives on a slime mould Fuligo septica in northern Europe; H. viridis is found on species of Lactarius and Russula in northern Europe and North America; H. cervinus grows on HELVELLACE# and large PEzIZACE# in Europe; H. fulgens appears on the bark of pine trees in Finland and Sweden; H. Stuhlmanni is confined to Polyporus bukabensis in Central Africa; H. chrysostomus is reported from Ceylon and H. flavescens on a Polyporus in North America. Hypomyces lactifluorum planes down 86 ra MYCOLOGY the gill surfaces of the Lactarius sp. on which it grows, converting an otherwise grayish-white fruit body into a cinnabar-red one. It is found in the woods about Philadelphia, Pa. The fungi belonging to the family LABOULBENIACE# are included in 28 genera and approxi- mately 152 species, and have been made known largely through the studies of Prof. Roland Thaxter of Harvard University. A few species are found in Europe, in the tropics of Africa, America and Asia, but North America is extraordinarily rich in specific forms. They occur on dipterous, neuropterous and coleopterous insects, especially those which live in damp places or in the water. The corn-smut Ustilago maydis is a parasite confined exclusively to the maize plant, Zea mays, and to the closely related if not identically the same grass the teosinte; Euchlena mexicana.as pointed out some years ago by the writer! as proof of the common origin of these two grasses. Wherever maize is cultivated the smut is found associated with it. The rusts (UREDINE#) are among the most specialized of fungi in their parasitic habits, some species being confined to one or two hosts. They ascend with their host plants above the snow line on high moun- tains and toward the poles wherever flowering plants and ferns grow. Whole genera are confined, however, to certain regions. Thus the genus Ravenelia which lives on mimosaceous and cesalpinaceous plants extends north to the 40° north latitude. Many rust fungi are iden- tically the same in North America, north and middle Europe, and of the 500 species known from North America and 400 European rusts approximately 150 species are common to both countries. Only a few Mediterranean species are found in North America, as Uromyces gly- cyrrhize and Puccinia Mesneriana. A less number of species are com- mon to North and South America. It is noteworthy that Puccinia malvacearum introduced into Spain from Chile in 1869 has in the forty- six years which have elapsed since its introduction into Europe spread over the world. The genus Exobasidium includes 18 species of fungi which cause the formation of fleshy galls chiefly on plants of the family ERicacEz&. Tabulated the principal species are: Exobasidium vaccinti on Vaccinium, Europe, Siberia, America. Exobasidium rhododendri on Rhododendron, Europe, America. 1 HARSHBERGER J. W.: Cont. Bot. Lab. Univ. of Pa., 1901: 234. FOSSIL FUNGI AND GEOGRAPHIC DISTRIBUTION 87 Exobasidium ledi on Ledum, Vinland. Exobasidium andromed@e on Andromeda, “urope, North America. Exobasidium azale@ on Azalea, North America. Exobasidium antarclicum on Lebetanthus, Patagonia. Exobasidium gaylussacie on Gaylussacia, Brazil. Exobasidium leucothoes on Leucothoé, Brazil. Exobasidium lauri on Laurus, Italy, Portugal, Canaries. Exobasidium Warmingii on Saxifraga aizoon, Greenland, Tyrol, North Italy. In closing this consideration of the geographic distribution of the fungi, the interest which attaches to it as a study may be best empha- sized by giving in tabular form the distribution of the species belonging to a single family. The family CLATHRACE# includes eleven genera of highly specialized morphology. FAMILY CLATHRACE. Te Clathrus cancellatus, Mediterranean Region, South England, North America. Clathrus columnatus, North and South America. 2. Blumenavia rhacodes, Brazil. . Ileodictyon cibarium, Australia, New Zealand, South America. . Clathrella chrysomycelina, Tropic South America. Clathrella pusilla, Australia, New Caledonia. Clathrella kamerunensis, Cameroon. Clathrella Preussti, Cameroon. Clathrella crispa, Central and Tropic South America. . Sumblum periphragmoides, Tonkin, Java, Ceylon, East Indies, Mauritius. Simblum spherocephalum, North and South America. . Colus Miilleri, Australia. Colus hirudinosus, Mediterranean Region. Colus Garcia, Tropic South America. Colus Gardneri, Ceylon. 7. Lysurus mokusin, China. 8. Anthurus borealis, North America. Anthurus Clarazianus, Argentina. Anthurus Woodii, Natal. Anthurus Miillerianus, Australia. Anthurus cruciatus, Tropic South America. - 88 MYCOLOGY g. Aseroé rubra, New Zealand, Australia, Java, Ceylon, Tonkin, South America. 10. Calathiscus sepia, East Indies. Calathiscus Puiggarii, South Brazil. Kalchbrennera corallocephala, Africa, Cameroon, Zambezi Region. II Cape, Natal, Angola, CHAPTER X PHYLOGENY OF THE FUNGI One of the most consistent attempts at representing the phylogeny of the fungi has been made by Dr. O. Brefeld through his researches which were published in collected form in “Untersuchungen aus dem Gesammtgebiet der Mykologie.’’ As these volumes are bulky ones, a student of Brefeld, Dr. F. von Tavel, has given a useful summary of the chief points in his teacher’s system in a book published in 1892, entitled “ Vergleichende Morphologie der Pilze.”” The phylogeny of the higher fungi, according to Brefeld, is based on the assumption, that there is an entire absence of sexual organs in all of those groups above the PHYCOMYCETES, but this view has been rendered untenable owing to the discovery of undoubted sexual organs among the ASCOM Y- CETALES and the discovery of nuclear fusions in some of the rusts, suggesting a sexual condition. However this may be, Brefeld and von Tavel hold that the PHYCOMYCETES are algal-like fungi and prob- ably derived from algal ancestors. The OOMYCETALES are not linked directly with any of the higher fungi, but the ZYGOMYCETALES through the former with sporangia and conidia have probably given rise to the HEMIASCI and directly through them to the ASCOMYCETALES. The forms of ZYGOMY- CETALES with conidia above are phylogenetically connected in the Brefeldian system though the HEMIBASIDII with the BASIDIO- MYCETALES. This in brief is an outline of the phylogenetic views of Brefeld, as expressed in a useful ground plan of the naturai system of hyphal fungi by von Tavel. The question is asked naturally, whether the origin of the fungi has been monophyletic, that is from a single ancestral form, or polyphyletic, from a number of distinct ancestors? This question can be answered only after an examination of the evidence. There are two orders of the PHYCOMYCETES, or algal fungi, namely, ZYGOMYCETALES and OOMYCETALES. As to the origin of these forms, the monophyletic view would have us derive the ZYGOMYCETALES from the OOMY- 8 * 9 go MYCOLOGY CETALES, which have been derived in all probability from an alga like Vaucheria with oogonia and antheridia, where the male sexual organs are smaller than the female. To derive the ZYGOMYCE- — TALES from such a group would necessitate that the sexual organs become of equal size. Entomo phthora is a connecting form where the sexual organs ap- proach each other in size. This genus is then connected by insensible differences with the heterogamic hermaphroditic moulds where there is an appreciable difference in the size of the two cells that conjugate, the larger being the female, the smaller the male, as in Absidia spinosa and Zygorhynchus heterogamus. These are directly connected with the homogamic hermophrodite moulds and these with the homogamic heterothallic forms. The polyphyletic view necessitates the deriva- tion of the OOMYCETALES from a Vaucheria-like ancestor, and the ZYGOMYCETALES from a Zygnema-like ancestor, where conjugation of similar cells (gametes) is found. The polyphyletic origin of the fungi is emphasized by the adherents to the doctrine of the origin of the ASCOMYCETALES from red alge, as there are three po:nts of contact: first, sac fungi with highly developed trichogyne (sterilized archicarp) of the Collema type with red alge-like certain existing forms; second, sac fungi with highly developed trichogyne of the Polystigma type; third, sac fungi with simple generalized copulating gametes of the Gymnoascus type. We are, however, not in the position to name any known red alga as the progenitor of the sac fungi, and it is far more reasonable to search for one in another fungous line, where, in the light of present-day knowledge, there are known forms with sexual organs very much like the sexual organs of simple, known forms of the Ascomycetales. We are not now in a position to name any known phycomycete as a probable ancestor, though the likelihood is that the original stock possessed phy- comycetous characters, thus attributing a monophyletic origin to them. One of the most instructive forms suggesting a mode of transition from the PHYCOMYCETES to the ASCOMYCETALES, is Dipodascus. Its sexual organs are strikingly like those of certain MUCORACE or PERONOSPORACE# in their young stages. The sexual organs can be recognized as antheridium and oégonium either from the same thread (homothallic) or from different threads (heterothallic). After absorption of the wall between the gametes, the fertilized o6gonium (or zygote) grows out into an elongate stout ascus, or zygogametangium with the PHYLOGENY OF THE FUNGI on production of numerous spores.' Hremascus also represents such a con- necting form. From Eremascus by reduction forms like Endomyces arose which in two diverging series connects various ascomycetous fungal forms. One series shows sprout conidia, the other oidia. The yeast series, the Ewoascus series are thus connected. Some would have us derive the LABOULBENIACE# from red algal ancestors, but another opposing view is that these unusual fungi have had a Monascus-like ancestor. The other branch leads to the Basidiomycetales where the most primitive forms have not typical basidia, as in the Hemibasidii, and which are connected with such primitive types as are included in the family. ENTOMOPHTHORACE#.” The differentiation of types within these large phyla will be dealt with as we proceed with a discussion of the various groups of PHYCOMYCETES and MYCOMYCETES. 1 ATKINSON, GEO. F.: Phylogeny and Relationships in the Ascomycetes. Annals Missouri Botanical Garden, II: 315-376. 2 Cf. ENGLER und PRANTL: Die natiirlichen Pflanzenfamilien, I Teil Abt.: 60-63. MASSEE, GEORGE: A Text-book of Fungi, 1906: 182-195. CHAPTER XI MOULD FUNGI SUBCLASS PHYCOMYCETES The fungi of this subclass are distinguished by their siphon-like hyphe, because these hyphe are unicellular and multinucleate and sug- gest the alge of the family SrpHONACE to which Vaucheria belongs. Hence the fungi of the subclass PHYCOMYCETES (duxos, seaweed + woxns, a fungus) are usually designated as algal fungi. Although the absence of transverse septa in the hyphe is used as a fundamental char- acteristic, yet in the formation of the reproductive organs transverse walls or septa cut these organs off from the rest of the vegetative mycelium. ‘Transverse septa are found regularly in some of the genera, such as Dimargaris, Dis pira, Protomyces and Mucor, so that the general statement above is modified by such exceptions. A fungus, Leptomitus lacteus, found in ditches and rivers shows a characteristic segmentation of the hyphz, where through the deposit of a substance known as cellu- lin the lumen of the hyphe is nearly closed, but at the point of constric- tion, a small pore remains through which the protoplasm passes. There are genera of the family CHyTrIpIACE&, such as Reessia and Rozella in which the protoplasm during the vegetative state is not sur- rounded by a cell wall, but is naked, and amceboid in the host cells. The fungi of this subclass are saprophytic or parasitic, aquatic, or aerial, living endophytically as a rule. A few are parasitic on insects and fishes. Two orders are distinguished, viz., the ZYGOMYCET- ALES and the OOMYCETALES. ORDER: ZYGOMYCETALES The fungi of this order show a strongly developed mycelium con- sisting usually of unicellular, sometimes pluricellular, multinucleate hyphe. These hyphe are distinguished in the typic forms as the rhiz- oidal hyphe, aerial hyphe and reproductive hyphe. Vegetative re- 1 MASSEE, GEORGE: Text-book of Fungi, 1906: 242. Q2 MOULD FUNGI 93 production is never through motile zoospores, but through immotile spores produced in sporangia borne at the tips of the reproductive hyphe known as sporangiophores, or by means of conidiospores, chlamydospores (Mucor racemosus), oidiospores, or gemme. Sexual reproduction is by the conjugation of two similar or slightly dissimilar gametes, and the formation of a resting cell, or sexually produced spore, known as the zygote, or zygospore. Brefeld believed that this group gave rise to the higher groups of fungi and he showed an interesting series of transition forms from those like Mucor with a tvpic terminal sporangium (Fig. 13) with numerous sporangiospores (endospores) through Thamnidium elegans with a large terminal sporangium (mega- sporangium) and secondary lateral smaller sporangia (sporangioles, microsporangia) and Thamnidium chetocladioides (Fig. 32), where the absent terminal megasporangium is represented bya spine-like sporangi- phore, to Chetocladium, where the number of endospores in the spor- angioles is reduced to one inclosed within the sporangium, which be- haves as a conidiospore; thence to Piptocephalis, where the monosporous sporangiole has become virtually a conidium, or conidiospore. He re- garded the ascus as potentially a sporangium, but recent discoveries have shown this hypothetic view to be untenable, so that his views as to the origin of the ASCOMYCETALES and the BASIDIOMYCE- TALES from the ZYGOMYCETALES must be considered as not satis- factorily proved. Blakeslee, who has studied the sexual reproduction in the moulds, finds that they may be divided into two groups, the homothallic (mon- cecious) and the heterothallic (dicecious) forms. The homothallic moulds are those in which the sexual gametes, which conjugate, arise from the same mycelium, while the heterothallic forms are those in which two distinct mycelia contribute the gametes which ultimately unite sexually. The homothallic (hermaphroditic) moulds he divides into the heterogamic hermaphrodites in which there is an inequality in the size of the gametes (the large one being female and the small one male), and the homogamic hermaphrodites in which the gametes are of equal size. The heterogamic hermaphrodites include the following fungi: Syncephalis, Dicranophora fulva, Absidia spinosa, Zygorhynchus heterogamus, Z. Malleri, Z. Vuillemini. The homogamic hermaph- rodites comprise: Mortierella polycephala, Mucor genevensis, S pinellus fusiger and Sporodinia grandis (Fig. 28). The dicecious, or hetero- 94 MYCOLOGY thallic species are all homogamic, that is, there is no difference in the size of the two gametes which conjugate. This group includes such Fic. 28.—Zygospore formation in Sporodinia grandis from material growing on toad- stool. (Slide prepared by H. H. York, Cold Spring Harbor, July 29, 1915.) ome | lO] Fic. 29.—Conjugation and development of zygospores between + and — races of black mould, Rhizopus nigricans. . fungi as Absidia cerulea, Mucor mucedo, and five other forms of Mucor, Phycomyces nitens and Rhizopus nigricans (Fig. 29). ‘Taking the con- MOULD FUNGI 95 jugation in Mucor mucedo as an illustration of the method, we find that the hyphe of two distinct mycelia, which may be designated as the + and — strains, give rise to lateral club-shaped branches. ‘The tips of these two branches (progametes) come into contact and a terminal cell (gamete) is cut off from each branch respectively by a transverse wall. The double partition wall is dissolved away by an enzyme, and the two cells coalesce, their nuclei uniting in pairs. A zygospore is formed, as a resting spore (Figs. 28, 30 and 33). It becomes covered with a thick, warty brown coat. The zygote (zygospore) germinates after a period of rest producing at once, because of the concentrated foods it contains, a sporangiophore bearing a terminal sporangium with sporangiospores. Sometimes the gametes fail to unite through some check to the normal conjugation and the two gametes may then round off and form thick-walled azygospores, and the size of these azygospores depends upon the size of the gametes from which they develop. Blakes- lee has discovered that for the production of zygospores in heterothallic moulds the contact of the hyphe of two distinct mycelia designated + and — are essential. If two — races or two + races meet, there is no result. In the homothallic moulds, the two conjugating gametes may arise from the same mycelium. Where the + race of one species of mould meets the — race of another species imperfect “‘hybrids”’ are formed. The testing out, maleness or femaleness, of the different races is made possible by growing in proximity different kinds of moulds, where a reaction occurs and imperfect hybrids are formed one race must be plus and the other minus. Where the hermaphrodite forms are grown, it is noticed that one gamete is larger and the other smaller, and it is assumed, that the larger gamete is female and the smaller one male. The race of dicecious Mucors, designated tentatively (+), shows a sexual reaction with the smaller-or male gamete, while the (—) or vegetatively less vigorous race shows a reaction with the larger or female gamete. It is inferred that the + race of dicecious mucors is female and the — race, male. The immediate stimulus to the formation of the progametes prob- ably lies in the contact of hyphe from different strains through the osmotic activity of the hyphal contents. For this reason progametes fail to form in relatively dry air. By suspending two small bags filled with bread soaked in dilute orange juice and inoculated with mould spores, any influence which the substratum might show is eliminated. 96 MYCOLOGY Zygospores were formed in one week where the aerial radiating hyphe had come into contact. By this experiment all influences exerted through the solid culture media, or which were due to contact of vege- tative mycelia, were eliminated. The sporangia of Mucor mucedo are raised upon the ends of sporangio- phores. When fully formed the sporangium consists of a wall beset with spicules of calcium oxalate, the spores separated from each other by a slimy intersporal substance (zwischensubstanz), and a columella which projects into the interior of the sporangium. The formation of spores in Rhizopus nigricans and Phycomyces nitens has been studied by Swingle,' who finds that the columella is formed by the cutting upward of a circular surface furrow or cleft, thus cleaving out the columella over the end of which a plasma membrane is formed. The spore plasm of Rhizopus divides into spores by furrows pushing progressively inward from the surface and outward from the columella cleft both systems branching, curving and intersecting to form multinucleated bits of pro- toplasm (the spores) surrounded only by plasma membranes, which become the spore walls and separated by spaces filled with the inter- sporal substance (zwischen substanz). The endospores, or sporangio- spores, of Rhizopus nigricans and Sporodinia grandis are multinucleate, while those of Pilobolus are binucleate, according to Harper. ‘The es- cape of the mature sporangiospores takes place when a portion of the sporangial wall is dissolved. The spores escape imbedded in the inter- sporal slime, which dries up liberating the spores. Certain species of Mucor are capable of fermenting grape juice, the power of fermentation depending on the species. The following species produce alcoholic fer- mentation (Lindner) : Quantity of alcohol Species by volume, per cent. IVCOTES GNSS CIT 5.0 tacos cet u en hae ere ee ee Boulit MGOPLOIL DOSPOTtUS =. Ae ee as eee eee oil WEALCOY GAVONAGUS idee doc cairn cn tae I CRA 2.83 WE COYPLUMIUCUS 2s crn oe aiae GI Rac aie eee eee 4.62 Mucor pirelloides....... e ATE STE ES cree 1.00 MACOTIVACEMOSUSS IAAT b, Riatae be LED EI RED tee 4.62 MniCOr ER OUXIGNUSH Reece Levene ue a OL ears Seeds IMENGOTACTUSCO=GV ANUS perro te Me ee een ee 4.00 MMGUCOP EC ONCVCNSIS a ly-rwarot hott sa en eee tel mee eee 5.21 'SwINGLe, DEAN B.: Formation of the Spores in the Sporangia of Rhizopus nigricans and of Phycomyces nitens. Bull. 27, Bureau of Plant Industry, 1903. MOULD FUNGI 97 Key To FAMILIES OF THE ORDER ZYGOMYCETALES Non-sexual spores in sporangia, which in some genera are reduced to conidioid bodies. A. Non-sexual spores formed in sporangia in many cases accom- panied by conidiospores. (a) Sporangia (at least the main sporangia) with columella. Conidiospores absent, or only sparingly found. Zygospores naked, or only covered by curled outgrowths of the sus- pensors. I. MucoracE&. (6) Sporangia without columella; zygospore surrounded by a thick covering of hyphe. II. MortTIERELLACE. B. Non-sexual spores as conidiospores. Sporangia exceptionally present. (a) Conidiospores single. Zygospores formed directly by the united gametes. I. Sporangia present transitional to conidia; sporangia monosporic and polysporic. III. CHOANEPHORACE. 2. Sporangia never present; parasitic on other MUCOR- ALES. IV. CH#TOCLADIACEZ. (b) Conidia in chains zygospore formed where the bent ends of the gametes unite. V. PiprocEPHALIDACE2. Non-sexual spores as true conidiospores borne singly at the end of conidiophores. VI. ENTOMOPHORACES. ; Famity 1. Mucorace#.—The mycelium of the true moulds is homogeneous, or it becomes heterogeneous through differentiation into aerial and nutritive hyphe. Non-sexual reproduction by the forma- tion of endospores in sporangia. The sporangia here may be simple or branched. The sporangia are all alike, or there are as in Thamnidium two different types known as megasporangia and microsporangia. The larger sporangia have a columella, while the smaller ones are mostly without a columella, but occasionally a columella is present. The formation of conidiospores is unknown in the family. The zygospore may arise by the fusion of two similar gametes formed from the same mycelium (homogamic hermaphrodites) or by the union of two slightly dissimilar gametes the product of the same mycelium (heterogamic her- mophrodites), or it arises by the conjugation of similar gametes (+ and — races) from two distinct mycelia (heterothallic and homogamic). yy / 98 MYCOLOGY The important genera of the family are Mucor, Rhizopus, Phycomy- ces, Absidia, Sporodinia, Thamnidium, Dicranophora, Pilaira and Pilo- bolus. The genus Mucor, a key for the identification of the species will be given at the end of the book, was established in 1729 by Micheli. The genus may be divided into three groups of species. The first division includes those species with unbranched sporangiophores, such as Mucor mucedo. The second group comprises the moulds with clus- tered branches of the sporangiophores, as Mucor corymbifer, M. erectus /~ M. fragilis, M. pusillus, M. racemosus, and M. tenuis. The third sec- tion is made up of species the sporangiophores of which show sympodial dl essay, e Fic. 30.—Details of Chlamydomucor racemosus showing oidia, sporangia and. zygo- spore formation. : branching. Such are Mucor alternans, M. circinelloides, M. javanicus, M. Rouxii and M. spinosus. (Also consult pages 695-702.) The oldest known species, Mucor mucedo, was described fully for the first time by O. Brefeld in 1872. Stiff sporangiophores, 3° to 4op thick, arise from the mycelium and are 2 to 15 cm. in height. Each bears a single globular sporangium roo to 200 in diameter and the sporangial wall is beset with fine needles of calcium oxalate. The spores - are ellipsoidal 3 to 6u by 6 to 124 with faint yellowish cell contents. As previously described, conjugation is between two similar gametes from + and — mycelia. Mucor racemosus, also known as Chlamydomucor MOULD FUNGI 99 racemosus (Fig. 30), shows the clustered branching of the sporangio- phore and in addition the hyphz are marked by the intercalary forma- tionof chlamydospores. This mould produces sporangiophores 8 to 20u thick by 5 to 4o mm. in height, bearing brownish sporangia 20 to 7op in diameter. The globular colorless spores are 5 to 8u broad by 6 to rop in length. This mould which grows on bread and decaying vegetable matter, and if cultivated submerged in beer-wort, the hyphz swell ir- regularly and a large number of transverse septa appear, which divide the hyphe into barrel-shaped portions. These cells or gemme can be separated readily, and when free, they become spheric and multiply by budding, as in the true yeasts, and the submerged spores also bud and constitute the so-called Mucor-yeast. At the surface of the liquid, they develop the typic mould form. Mucor racemosus, according to Hansen, is the only mould capable of inverting cane-sugar solution. It produces in beer-wort as' much as 7 per cent. by volume of alcohol. Mucor erectus, which grows on decaying potatoes, produces azygospores as well as zygo- spores. It has the same appearance as the preceding and possesses an active power of fermentation. In beer-wort of ordinary concentration, it yields up to 8 per cent. by volume of alcohol, and in dextrin solutions it induces alcoholic fermentation. Mucor spinescens, which grows on Brazil nuts, has spiny projections on the rounded upper surface of the columella. Mucor (Amylomyces) Rouxii occurs in the so-called “‘Chinese yeast,” which is in the form of small whitish cakes, consisting of rice grains kneaded together with assorted spices. These cakes are powdered and mixed with boiled rice upon which the mycelium grows, converting the rice by slow degrees into a yellowish liquid which con- tains glucose produced by the diastatic ferment of the fungus. The black mould Rhizopus nigricans (Mucor stolonifer) grows on bread and other organic substrata (Fig. 31). Several sporangiophores arise from a single point of origin, namely, at the top of a mass of rooting (rhizoidal) hyphe which constitute an adhesive organ or oppressorium. Each erect stalk bears oblate spheroidal sporangia with distinct colu- mella and sporangiospores, 6 to 174 long. Arising from the base of the clustered sporangiophore is a horizontal hyphe, which often attains a length of 3 cm. and is known as the stolon, or stoloniferous hypha. When the tip of this stolon comes into contact with the substratum a new appressorium is formed from which arises a number of sporangio- phores bearing sporangia (Fig. 31). This method of growth enables the 100 MYCOLOGY black mould to spread rapidly and it sometimes chokes out other moulds growing in competition with it on the same nutritive medium. In1818, on account of this method of growth, it was named by Ehrenberg Mucor stolonifer. Related to this fungus is one named Rhizopus ory- zee which grows in Ragi. The fungus Phycomyces nitens is found in empty oil casks, on oil cakes and in concentrated fodder. It puts forth stiff sporangiophores 7 to 30 cm. long and 50 to 150u in diameter which bear at the summit black globular sporangia 0.25 to 1.0 mm. in diame- ter, filled with yellow-brown, thick-walled endospores, 16 to 30p long and 8 to 15u broad. Its zygospores are 300u broad and their” O) OP \ \ BY Pa i Fic. 31.—Black Mould, Rhizopus nigricans. A, Mature plant showing rhizoidal hyphe (myc); stoloniferous hypha (st); sporangiophores (sph); sporangia (sp). B, Younger cluster of sporangiophores and sporangia. (After Gager.) borders are covered with many forked projecting hyphe known as suspensoria. Recently H. Burgeff! has studied the variability, sex- uality and heredity of Phycomyces nitens and has brought his cultural investigations into line with the recent developments of cytology and genetics. His paper should be read by all students, who may be interested in the extension of the methods of genetics into an investigation of the lower plants. The genus A bsidia includes five species. In these fungi the suspen- sors are borne at the base of the two gamete cells which fuse to form the zygospore, which when mature is covered by a basket-like covering of 1 BuRGEFF, H.: Untersuchungen iiber Variabilitat, Sexualitét und Erblichkeit bei Phycomyces nitens Kuntze. Flora, Band 108: 353-448; review by G. V. Ubisch (Dahlem) in Botanisches Centralblatt, Band 128, Nr. 23: 630-632, 1915. MOULD FUNGI LOI straight appressoria, which hook together by their curved extremities, thus giving additional protection to the zygospore. Sporodinia grandis, the single species of another genus, lives on large fleshy fungi of the BiG. 32: —Sporangia of 1, Thamnidium elegans; 2, 3, 4, Thamnidium chetocladioides ; Se Chetocladium Jonesii. (After Brefeld.) families (Fig. 28) AGARICACE#, BOLETACE#, CLAVARIACE® and Hy- DNACEH&. Its sporangiophores 1 to 3 cm. high are finally brown in color and dichotomously branched. The sporangia are spheric with a deli- 102 MYCOLOGY cate sporangial wall, which soon disappears leaving the spores on a hemispheric columella. These spores are 11 to 7ou broad. The 300u broad zygospores are produced from similar branches of a dichotomously branched zygosphore. The mycelium of the species of Thamnidium enters the nutritive substratum. The large sporangia are terminal while the smaller secondary sporangia are borne on lateral branches in whorls below the terminal sporangium. ‘This is typically seen in Th. “@ Fic. 33.—Details of sporangia and sporangiophores of Pilobulus. 1, P. micro- Sporus; 2, P. roridus; 3, 4, 5, P. anomalus; 6, zygospore of P. anomalus. (After Brefeld.) E elegans (Fig. 32). A related species Th. Fresenti has an upright termi- nal sporangiophore, which is either sterile, or ends in a large terminal sporangium, while the smaller sporangia are as in 7h. elegans. In Th. amoenum, the lateral smaller sporangia are borne at the end of coiled secondary sporangiophores. The secondary sporangia suffer reduction in Th. chetocladioides (Fig. 32) which in addition to having a straight terminal spine-like hypha in place of the terminal sporangia has some of the lateral microsporangia replaced by sterile branches. The MOULD FUNGI 103 commonest species of Pilobolus (Fig. 33) is P. crystallinus which appears on horse dung. It has a few short feeding hyphe and an upright spor- angiophore swollen at the extremity by gas and water vapor and, there- fore, under tension. It bears at its extremity a flat rounded sporan- gium filled with sporangiospores. An explosion of the sporangiophore causes the whole sporangicum to be shot off a considerable distance. FAMILY 2. MORTIERELLACEZ.—This family consists of two genera Mortierella and Herpocladiella. The genus Mortierella, which is repre- sented by a coprophilous species, M. Rostafinski, has a sporangium borne on a sporangiophore which ar:ses in a definite way from a snare of hyphe that are knotted into a rounded mass at its base. In M. cande- labrum, the sporangiophore is branched candelabra-like. Brefeld men- tions Mortierella and Rhizopus as examples of the carposporangiate ZYGOMYCETALES, where the sporangiophores appear always at predetermined places on the mycelium, and not at indefinite points, as in the majority of other moulds. | FAMILY 3. CHOANEPHORACEZ.—Represented by a single genus Choanephora and a single species infundibulifer on flowers of Hibiscus in East Indies. FAMILY 4. CH@TOCLADIACEZ.—This is a small family of one genus (Chetocladium) and two species, (Ch. Jonesii and Ch. Brefeldii) (Fig. 32) which live parasitically on Mucor mucedo and Rhizopus nigri- cans. The terminal sporangia of Thamnidium are never formed and secondary sporangia are reduced to the unisporous condition suggesting conidiospores with pointed branches between them. FAMILY 5. PIPTOCEPHALIDACE®.—Three genera Piptocephalis, Syncephalis and Syncephalastrum are recognized in Die Natiirlichen Pflanzenfamilien. The eight species of Piptocephalis are parasitic on the mycelia of Mucor, Pilobolus and Chetocladium species (Fig. 37). The haustorial hypha flattens itself disc-like on the outer surface of the host’s hyphe and sends five rhizoidal branches into the host cells. An erect dichotomously branched conidiophore bears conidiospores in globular clusters at the ends of its principal branches. Some species of Syncephalis are parasitic on other fungi; but S. cordata grows on manure, presumably as a saprophyte. FamIty 6. ENTOMOPHTHORACEZ.—The mycelium of the fungi of this family is more or less richly developed and lives endozoically in animals, such as flies, mosquitoes, aphids, and seldom saprophytically as 104 MYCOLOGY Basidiobolus on the feces of frogs. Non-sexual reproductions is mainly by means of unicellular conidiospores which are discharged forcibly from the ends of tubular conidiophores. Sexual reproduction is by the conjugation of two gametes dissimilar in size, heterogamic and thus these fungi connect the ZYGOMYCETALES with the OOMYCETALES where oogamous reproduction is displayed. The zygospores formed in conjugation are spheric, while the azygospores formed on the mycelium without copulation are similar to the zygospores in struc- ture and appearance. The family includes seven genera, includ- Fic. 34.—Fly cholera fungus (Empusa musce). 1, Fly enveloped in mycelium; 2, fungus between hairs of the fly; 3, conidiophores and conidiospores; 4, germina- tion of spores; 5, formation of egg in Empusa sepulchralis. (After Thaxter.) See Henri Coupin, Atlas des Champignons, Parasite set Pathogenes de 1’ Homme et des Animaux, 1909. ing Empusa and Entomophthora, which may be chosen as types for discussion. The mycelium of Empusa musce (Fig. 34) is parasitic in the bodies of flies, destroying them in large numbers by an epidemic in the fall, known as fly-cholera. The short hyphe frequently bud like yeast cells. The conidiophores break through to the surface of the insect’s body, where the conidiospores 18 to 254 broad by 20 to 30p long are forcibly discharged. These spores bore their way through the chitinous covering of a healthy fly by means of a germ tube and the MOULD FUNGI 105 hyphe which enter the body of the fly bud like yeast cells, which are carried to all parts of the insect’s body. Later the parasitic hyphe arise from the gemme. Resting spores are unknown. Entomophthora is a genus of fungi inclusive of thirty species found on various insects in Europe and North America. Entomophthora spherosperma has a richly branched nutritive mycelium, which grows through the body of insects. After the death of the host, the hyphe break through the surface in connected strands part of which attach the larva, or insect’s dead body, to the substratum and part form a thick white mantle over the surface. The conidiophores are in branching bundles. The conidiospores are elongated ellipsoidal, 5 to 8u4 broad by 15 to 26u long. Secondary and tertiary conidia are found. The resting spores produced as azy- gospores are spheric and 20 to 35u broad with a smooth yellow wall. It grows on larve, especially frequent on the cabbage worm Pieris brassice in Europe and North America. BIBLIOGRAPHY OF THE ZYGOMYCETALES This is not intended to be a complete list of the works dealing in whole or in part with the mould fungi, but only a list of the works which may prove helpful to the student of mycology. Barter, G.: Etude sur les Zygospores des Mucorinées, Thése présentée a l’Ecole de Pharmacie. Paris, pp. 136, pls. 1-11; Observations sur les Mucorinée. Annales des Sciences naturelles, ser. 6, 1-15: 70-104, pls. 4-6. Sur les zygo- spores des Mucorinées. Annales des Science naturelles, vi ser., I: 18, 1883; Nouvelles observations sur les zygospores des Mucorinées, do., I: 19, 1884. BLAKESLEE, ALBERT F.: Sexual Reproduction in the Mucorinee. Proceedings American Academy Arts and Sciences, xl: 205-319 with 4 plates and bibli- ography; The Biological Significance and Control of Sex. Science, new ser. xxv: 366-384, March 8, 1907; Papers on Mucors (a review). Botanical Gazette, 47: 418-423, May, 1909; Heterothallism in Bread Mould, Rhizopus nigricans. Botanical Gazette, 43: 415-418, June, 1907; A Possible Means of Identifying the Sex of (+) and (—) Races in the Mucors. Science, new ser. xxxvii: 880- 881, June 6, 1913; On the Occurrence of a Toxin in Juice Expressed from the Bread Mould, Rhizopus nigricans. Biochemical Bulletin II: 542-544, July, 1913; Conjugation in the Heterogamic Genus Zygorhynchus. Mycologisches Centralblatt Il: 241-244, 1913; Sexual Reactions between Hermaphroditic and Dicecious Mucors. Biological Bull., xxix: 87-102, August, 1915; Zygospores and Rhizopus for Class Use. Science, new ser. xlii: 768-770, Nov. 26, rors. BREFELD, O.: Botanische Untersuchungen iiber Schimmelpilze, Heft 1, Zygomy- ceten, pp. 1-64, Taf, 1-6, 1872; Untersuchungen aus den Gesamtgebiete der Mykologie, ix, 1891. 106 MYCOLOGY BUCHANAN, EsTELLE D., and BucHANAN, RosBertr E.: Household Bacteriology, 1914: 66-72. DE Bary, A.: Comparative Morphology and Biology of the Fungi and Bacteria, 1887: 144-160. Encier, A. and Gc, Ernst.: Syllabus der Pflanzenfamilien, 7th Edition, ro12: 37-38. GorTNER, Ross A. and BLAKESLEE, A. F.: Observations on the Toxin of Rhizopus nigricans. American Journal of Physiology, xxxiv: 354-367, July, 1914. JORGENSEN, ALFRED: Microdrganisms and Fermentation, 3d Edition, 1900: 97- II5. KEENE, Mary L.: Cytological Studies of the Zygospores of Spordinia grandis. Annals of Botany, xxxvili: 455, 1914. Ki6ckeEr, ALB.: Fermentation Organisms, 1903: 170-186. LAFAR, FRANZ: Technical Mycology, II, part 1: 1-30, 1903. LENDNER, AtF.: Les Mucorinées de la Suisse. Materiaux pour la Flore Crypto- gamique Suisse ITI, Fasc. 1: 1-177, 1908. ScHRrOTER, J.: Mucorinéz, Die natiirlichen Pflanzenfamilien, I, Teil 1. Abt. r19- 142, 1897. StEvENS, F. L.: The Fungi which Cause Plant Disease, 1913: to1—108. SWINGLE, DEANE B.: Formation of the Spores in the Sporangia of Rhizopus nigri- cans and of Phycomyces nitens. Bureau of Plant Industry No. 37, 1903 with 6 plates. UNDERWOOD, LucrEN M.: Moulds, Mildews and Mushrooms, 1899: 24-28. VON TAVEL, F.: Vergleichende Morphologie der Pilze, 1892: 25-40. WETTSTEIN, RrcHARD R. von: Handbuch der systematischen Botanik, 1911: 160- 164. CHAPTER XII OOSPORE-PRODUCING ALGAL FUNGI ORDER II. OOMYCETALES The fungi of this order were derived probably from some ancestor, or ancestors, which through the loss of chlorophyll became dependent on extraneous supplies of organic food. If we look for such an ancestral form among the alge, we find that it must have been related to Vau- cheria, if not identic with that filamentous siphonaceous green alga with reproductive organs, as oogonia and antheridia. Vaucheria isa unicellular filamentous sparingly branched cell with a thin cell wall and multinucleate. Hence it is sometimes called a cenocyte. Similarly, the structural features of the more primitive OoMYCETALES are like Vaucheria, but the absence of chlorophyll is distinctive. The forma- tion of non-sexual sporangia with the formation of zoospores, or swarm spores, known as zoosporangia is a feature of the fungi of this order. As there is a pronounced difference between the male and female sexual organs, oogamous reproduction is the rule. The oogonium is compara- tively large and contains one or more oospheres, which are fertilized by the sperm cell, which swim to it by cilia, creep to it, or are carried into the oogonium through a fertilization tube. Sexual reproduction in these fungi has been investigated cytologically by a number of students, and they have found that the nuclear changes concomitant with fertili- zation are characteristic. Albugo candida, A. lepigoni, Peronospora parasitica, Plasmopara, Pythium and Sclerospora show a single large cen- tral oosphere with a single nucleus, while the remaining nuclei pass from the gonoplasm into the periplasm. A process is sent into the oogonium from the antheridium and a single male nucleus passes into the oogo- nium. A cell wall is developed about the oospheres and the male and female nuclei unite, while the periplasm is used in the formation of the spore wall (episporium). The ripe oospore has a single nucleus in Peronos pora parasitica, while in Albugo, it becomes multinucleate after nuclear division. A central oosphere (gonoplasm) surrounded by peri- 107 108 MYCOLOGY plasm occurs tn Albugo bliti and A. portulace and the oosphere is multinucleate and the nuclei present fuse in pairs with a number of sperm nuclei which enter from the antheridium. The oospore which arises is multinucleate. This method is considered by mycologists to be the primitive one as displayed in these two species, the uninucleate oospheres of the first-named species having been derived from the multi- nucleate. An intermediate position is occupied by Albugo tragopogonis, where at first the oosphere is multinucleate but by the degeneration of all but one female nucleus becomes uninucleate. Claussen! finds that Saprolegnia monoica develops both antheridia and oogonia, the latter at first being filled with protoplasm and many nuclei which wander to the periphery and undergo degeneration with a few nuclei left over. These nuclei divide once mitotically. Around these daughter nuclei the protoplasm collects to form the egg cells. Each egg has a single nucleus near which is the coenocentrum of Davis, but which Claussen thinks is a true centrosome. The simple or branched antheridia form germ tubes which enter the wall of the oogonium and a single male nucleus fuses with the nuclei of the egg cells to form the oospore. Claussen contrasts the life cycle, as determined by his investigations, with those of Trow in the following diagrammatic presentation: TRrow Diploid Haploid Diploid Ye Antheridium—Male nucleus _ gs Oospore, Mycelium Oospore Multinucleate \. \Oogonium Egg cell—Egg nucleus / ——$+— CLAUSSEN Haploid Diploid. Strasburger considers that the superfluous nuclei in the oogonia and the antheridia are Comparable with the superfluous egg nuclei of certain of the brown seaweeds belonging to the family FucAcE&%. When the oospores germinate, they either produce directly a mycelium, or give rise to zoospores. The fungi of this order are essentially parasitic, being found in this condition as endophytic parasites, or as endozoic parasites on fishes and insects and Euglena. 1 CLaussEN, P.: Ueber Eintwicklung und Befructung bei Saprolegnia monoica. Festschrift der Deutsch. Bot. Gesellsch., xxvi; 144-161 with 2 plates, 1908. OOSPORE-PRODUCING ALGAL FUNGI 10g Kry To FAMILIES OF THE ORDER OOMYCETALES A. Zoosporangia, oogonia and antheridia present; conidia absent. (a) Mycelium well developed. 1. Antheridium forming motile spermatozoids, which enter the oogonium. Family 1. MONOBLEPHARIDACE#. 2. Antheridium not forming spermatozoids, fertilization through an antheridial tube, or beak. Family 2. SAPROLEGNIACEZ. (b) Mycelium poorly developed, sometimes represented by a single cell. t. Fruit body as a single cell or by division forming a sporangial sorus; parasites on alge, protozoans, rarely on flowering plants. Family 4. CHYTRIDIACEZ. 2. Fruit body through division a chain of cells which develop sometimes into zoosporangia, sometimes into antheridia and oogonia. Family 5. ANCYCLISTACEZ. B. Conidia present. Family 3. PERONOSPORACE®. The following descriptions of the above five families are presented in order to introduce the student to the characters which fundament- ally distinguish them. Therefore, all generic keys are omitted because the introduction of them under each family would increase the size of the book unduly. FAMILY 1. MONOBLEPHARIDACE&%.—This family is represented by the genera Monoblepharis and Gonapodya. The genus Monoblepharis is represented by two species of which M. spherica is the most com- mon. It is an aquatic fungus found growing saprophytically on dead animal and plant parts under water. The hyphe of the mycelium are tubular, branched and unicellular. The swarm spores (zoospores), which are formed much as in Saprolegnia, have only a single flagellum. The oogonia are either terminal in position or interstitial and there is no differentiation of an outer periplasm, but the whole protoplasm of the oogonium contracts to form an oosphere. Later a pore appears ‘at the apex of the oogonium through which the uniciliate spermatozoids enter to fertilize the egg cell. The antheridium in M. spherica appears as a penultimate cell immediately below the oogonia. An opening is formed at the top through which the spermatozoids escape. The oosphere on fertilization becomes an oospore. Because of the aquatic i fe) MYCOLOGY habit and formation of motile spermatozoids, Brefeld considers Mono- blepharis to be the most primitive of the OOMYCETALES. FAMILY 2. SAPROLEGNIACEH.—The members of this family, as their name indicates, are saprophytes on both dead plants and animals in water with the exception of the fungus which causes the salmon disease and it is both a saprophyte and a facultative parasite. The hyphe in the vegetative condition are relatively large, arising from delicate rhizoids which penetrate the substratum. Swarm spores which are biciliate are formed in terminal, long, tubular zoosporangia opening by an apical pore through which the zoospores crowd their way out into the water. Sometimes, as they escape, they collect into ball-shaped masses which are caused to slowly roll about by the activity of the cilia. The female sexual organs, the oogonia, are terminal on the branches of the thallus hyphe. Several oospheres without dis- tinction of periplasm are formed inside of a single oogonium, and sometimes, as many as thirty or forty are found. The antheridia, which are club-shaped, are formed on slender branches of the mycelium which also bear the oogonia, or which are distinct from those which are ogogonial bearers. These antheridia approach the oogonia and an antheridial beak is formed which penetrates the wall of the oogonium and comes into contact with the oospheres by growing from one oosphere to another. Sometimes the antheridia, as in Saprolegnia monilifera, are not produced at all and the oogonia develop partheno- genetic oospores which germinate after a rest period of a few days to several months. The series representing reduction in sexuality begins with such forms as Saprolegnia monoica with an oogonium and an antheridium which develops a fertilizing process through Achlya polyandra, which forms antheridial branches which do not touch the oogonia, to Saprolegnia monilifera without any trace of antheridia. Androgynous forms are those in which the same hyphal branch develops both antheridia and oogonia and the diclinous species like Saprolegnia dioica and Achlya oblongata are those in which the antheridia and oogonia are borne on distinct branches. Saprolegnia ferax usually attacks only fishes, tadpoles and the spawn of frogs. It appears on aquarium-kept fishes on the sides of the body at the tail end, or among the gills. In the latter place, if abundant, it frequently causes asphyxiation and before this state is final the fish turns-over on its back and rises to the surface. In the OOSPORE-PRODUCING ALGAL FUNGI TET experience of the writer, immersion of the diseased fish in strong brine in many cases brings about a cure, if the growth of the fungus is not too great. Petersen! observed a sick bream in the lake of Fure S6 with a wound quite overgrown with Saprolegnia hyphe and he has found frog eggs which were attacked, the hyphe growing in the jelly around the eggs, penetrating into them. The fungus can be raised in the laboratory on dead fishes by allowing tap water to slowly flow over them in a jar. A few days are necessary to secure a copious growth. Frogs which die under the ice in winter for lack of oxygen float to the surface in the spring entirely covered by this fungus. It thrives best in the early stages of decay, for as putrefaction advances bacteria and infusoria increase to such an extent as to check the growth of the fungus. When air insects, such as gnats, fall into lake or pond water in great numbers, species of Saprolegnia, Achyla and Aphanomyces appear in great numbers and seem to form a gray felt on the surface. The vegetable materials on which the SAPROLEGNIACE mostly live are branches and shoots of trees, except Salix, owing to presence of salicin, which fall into the water. Second in importance are half- rotten rhizomes of Calla, half-rotten leaves and leaf stalks of Nuphar and Nymphea and other parts of aquatic plants which float on the surface. Species of the genus Achlya are mostly associated with such materials. Achlya polyandra have been repeatedly found by me on the fruits of Osage oranges which have fallen into the pond at the Univer- sity of Pennsylvania. The most favorable environmental conditions seem to be the absence of air about the hyphe, quiet, still, pure water, that does not contain much iron and a relatively open light surface. Low temperature conduces to the formation of oogonia, which also keeps in check other competing organisms (Fig. 35). FAMILY 3. PERONOSPORACEH.—This family is rich in parasitic forms which may be accounted as the cause of important diseases of cultivated plants. The hyphe of the mycelia are irregularly and copi- ously branched and are found mainly in the intercellular spaces of the host tissue sending short branches called haustoria into the adjoining living cells. These haustoria may be globular (Albugo = Cystopus), club-shaped (Peronospora corydalis), branched (Plasmopara) (Fig. 36), or branched and snarled (Peronospora). Septa are absent except 1 PETERSEN, HenninG E.: An Account of Danish Fresh-water Phycomycetes. Annales Mycologici, viii, No. 5, 1910. I1I2 MYCOLOGY when the reproductive organs are formed. Non-sexual spores, or conidiospores, are borne on conidiophores which may remain within the host (Albugo = Cystopus), or grow beyond the surface. They may be, either simple or branched. These conidiospores either germinate, as in Phytophthora infestans and Peronospora nivea by means of zoo- Fic. 35.—1, Zoosporangium of Achlya racemosa; 2, escape of zoospores; 3, fly- covered by mycelium; 4, zoospores of fungus; 5, Achlya ferax with zoosporangia and zoospores; 6, Achlya prolifera, 24 hours after germination of zoospores. 7, Achlya monoica, with antheridia and oogonia; 8, Achlya contorta. (After Henri Coupin, Atlas des Champignons Parasites et Pathogenes de l’Homme et des Animaux, pl. xviii, 1909.) spores which escape or by the protoplasm escaping (plasmatoparous), as in Peronospora densa, or by germ tubes, which in some species (Perono- spora lactuce@) appear at the end of the spore (acroblastic), or at the side of the conidiospore (pleuroblastic), as in Peronospora radii. The oogonia and antheridia, which are also present, are formed in the OOSPORE-PRODUCING ALGAL FUNGI 113 tissues of the host. The different kinds of nuclear fusion, which accompany fertilization, have been described previously. The oospore, which is formed, acts as a zoosporangium in some cases for it gives rise to numerous spores; or in other cases it produces a germ tube. In most of the forms, the oogonium contains a mass of protoplasm known as the oosphere. This is divisible into an outer clearer por- ? oo f ED yy ee x o G >> Sos. eo a ea a - rh oo Ne Pall na | iy ail Nai: \\, ‘ TS ay A eS me a aR . AN Fic. 36.—Plasmopora viticola. A, Conidiophore with conidiospores (nearby oospores); B, Haustoria; C, Swarmspore formation. A,950/1;B.C,600/1. (After Millardet in Die nattirlichen Pflanzenfamilien I. 1, p. £15), tion, the periplasm, and a denser more granular central portion, the gonoplasm. After fertilization, the oospore develops a thick wall of two layers, an extine and intine, and becomes a resting spore. It accumulates fatty substances, which are utilized when the spore germinates in the spring after a long winter’s rest. The family has had many revisions and in order to simplify matters Pythium and Albugo (Fig. 37), which are placed in separate families by some 8 II4 MYCOLOGY authors, are placed in the family PERONOSPORACE®. Details of the important forms which cause plant diseases will be given in the third part of this book. These fungi will be referred to under each genus following the systematic generic key which is here given. GENERIC KEY OF THE FAMILY. PERONOSPORACEZ Mycelium of these fungi parasitic or saprophytic in plant tissues; zoosporangia as distinct organs producing biciliate zoospores. Zoospores formed out of protoplaem which escapes out of the conidia. 1. Pythium. Zoospores formed within the zoosporangia. 2. Pythiacystis. Zoospores elongate. 3. Nematos porangium. Mycelial hyphe branching non-septate usually coarse, of strictly parasitic habit. Conidiophores short, thick, subepidermal, conidia in chains. 4. Albugo Conidiophores longer superficial, simple or branched, conidia not in chains. Conidiophores _scorpioid cymosely branched conidiospores developing swarmspores. 5. Phytophthora. Conidiophores simple, or branched monopodially; conidia sprouting as a plasma, or by swarm spores. Con- Seats MaESe idiophores regularly branched. Cystopus (Albugo) portula- Conidiophores simple erect with a cee, on purslane, Portulaca an onere . aisiece. He GoldienSanias swollen end (basidia-like) bearing Harbor, L.I., July 24, short sterigma-like branches of equal IQ1S. “7° a length. 6. Basidiophora. Conidiophores with lateral branches developed normally of unequal length. Conidiophores stout, with few branches, oospore united to wall of oogonium. 7. Sclerospora. Conidiophores slender, freely branched persistent; oospore free. 8. Plasmopara. Conidiophores eae forking branches; conidiospores sprout- ing with a germ tube. Upper end of conidiospore with a OOSPORE-PRODUCING ALGAL FUNGI II5 papilla through which the germ tube grows (acroblastic). 9. Bremia. Conidiospores without papilla; pleuroblastic. to. Peronos pora. The most important species of these genera from the standpoint of the plant pathologist are the following enumerated below with their common English names where such have been given. Scientific name Pythium de Baryanum | Pythiacystis citriopthora......| Albugo (Cystopus) candida... Albugo (Cystopus) portulace . | Phytophthora cactorum Phytophthora infestans Phytophthora phaseoli 44). Plasmo para cubensis (Fig. Plasmopara Halstedii........ Plasmopara viticola Bremia lactuca............. Peronos pora effusd.......... Peronospora parasitica....... Peronospara Schleideniana.. .| English name Damping-off fungus...... Brown rot of lemon...... White rust of crucifers.. .| White rust of purslane... Mildew of succulents... . .| Late blight of potato... .. Downy mildew of beans. Downy mildew of cu- cumber. Downy mildew of grape.. Downy mildew of lettuce. Mildew of spinach Downy mildew of crucifers Onion mildew Host plant Seedlings Lemon fruits Cruciferous plants Portulaca oleracea Cacti, etc. Potato Lima-bean | Cucumber | Helianthus annuus and | H. tuberosus | Grape vine | Cynara, Cineraria, Lactuca | Spinach Cabbage | | Onion CHAPTER. XUt OOMYCETALES (CONTINUED) FAMILy 4. CHYTRIDIACEZ.—This family according to some authors is made to include six families which are here reduced to six subfamilies. It includes fungi of short vegetative duration, which may be a few days in length. The swarm spores quickly give rise to new generations. The resting period is represented in the case of the endophytic para- sites by the time which elapses between the growth of two successive crops of the host plants. The majority of the species of the family are true parasites, partly endobiotic, partly epibiotic, and a few are saprophytes. Half of the plant parasites live in fresh-water alge, nearly as many in flowering plants, some of which are in aquatic plants, some in swamp plants. About ten species are found on marine alge. All species are microscopically small, yet they cause galls, dwarfing, dropsy and crusts of the host plants. The mycelium is absent or in the form of slender protoplasmic filaments, occasionally as distinct one-celled hyphae. The cell, which produces the fruit body, frequently serves as the chief nutritive organ. Later, it divides to form zoospores. The true mycelium has weak develop- ment. The short germ tube merely serves as an organ by which the parasite gains entrance to the host cell, and in the endophytic forms, it disappears quickly, but in the epiphytic species, it serves as an haustor- ium, sometimes with rhizoidal extensions. In the better-developed forms of CLADOCHYTRIE#, the slender mycelium serves to carry the fungus from cell to cell of the host. The sporangia are always zoo- sporangia which develop swarm spores, or zoospores. They are thin- walled and quickly mature, or they are thick-walled and form resting sporangia. Sexual spores are formed in only a few types and the differ- ence between antheridia and oogonia is morphologically little pro- nounced. The swarm spores have as a rule a single flagellum, rarely do they have no such locomotory appendages. The sexually produced oospores have the appearance of resting sporangia with the empty antheridium attached as an appendage. Few of these fungi attack our 116 OOMYCETALES Piz, cultivated plants, but where the attempt is made to grow alge and other water plants, the fungi of this family occasionally do considerable damage. As an example of the first subfamily OLpIpEa&, may be chosen Olpidium endogenum, which lives in the cells of desmids and kills them. The zoosporangium found in desmid cells are oblate spheroids and develop a long tube which projects out of the desmid cell through which the zoospores with a single cilia escape into the water. O. ento- phytum is parasitic in such filamentous alge as Vaucheria, Clado- phora, Spirogyra. Olpidiopsis saprolegnie lives in the elongated cells of Saprolegnia, producing enlargements in the hyphe of the fun- gous host. The swarm spore bores a hole in the cell wall of its host and swelJls out into a zoosporangium which develops a tube through which the biciliate swarm spores escape into the water. The subfamily SYNCHYTRIE includes most of the fungi which attack the higher plants. Such are Syuchytrium decipiens on the hog peanut (Amphicarpea monoica); S. fulgens on the evening primrose (Oenothera biennis); S. stellarie on Stellaria; S. succise on Succisa pratensis; S. taraxaci on dandelion; S. vaccinii causing a gall on cranber- ries, Pycnochytrium globosum on violet, wild strawberry, blackberry and maple seedlings. P. myosotidis occurs on certain members of the borage and rose families. Cladochytrium tenue of the subfamily CLADOCHYTRIE# lives in the subaquatic tissues of the sweet flag, Acorus calamus, flag Iris pseudacorus and a grass, Glyceria aquatica. Its mycelium is widely distributed in the cells of its hosts. Spheric sporangia 184 wide and sometimes 66yu are formed as intercalary enlargements of the mycelium, or they are formed at the end of the hyphe, with a colorless supporting cell. They give rise to a short tube-like mouth which breaks out of the host cell. The zoospores are uniciliate. Representing the OocHYTRIE# is an interesting fungus first fully investigated by Nowakowski, namely, Polyphagus euglene, which attacks the cells of Euglena, a unicellular animal. Its mycelium con- sists of a central enlarged portion from which run out in a number of directions branches which end in extremely fine points which penetrate the cells of Euglena. The enlarged central portion develops a swollen tubular outgrowth into which its protoplasm wanders. The contents of this outgrowth then divide into numerous uniciliate swarm spores 1138 MYCOLOGY which escape into the water. Under certain conditions a cyst appears in place of a zoosporangium. ‘This is thick-walled and of a yellow color and enters a period of rest. After the rest period, the membrane of the cyst rupture and a sporangium appears. Cysts may arise by a kind of sexual union where two unlike mycelia fuse and the protoplasm of both flows out to form a cyst between the original cells. Urophlyctis pulposa attacks leaves and stems of Chenopodium and Atriplex species. U. alfalfe grows in the roots of the alfalfa in South America and Germany. FAMILY 5. ANCYCLISTACEH.—This is a small family consisting of fungi whose mycelium is very slightly developed and not easily distinguished from the fruit body. In one subfamily LAGENIDE&, the mycelium is entirely absent. In.the ANCYCLISTE&, there is a rich development of the mycelium which forms lateral tube-like branches, which penetrate other cells. The fruit bodies are sac-like and give rise to zoospores. Sexual organs are present as antheridia and oogonia, the contents of the former passing over completely into the latter. The oospore, which is formed, is found free in the oogonium. All of the known members of this family are endophytic parasites and the different stages of their development are short-lived. Lagenidium entophytum lives in the zygospores of species of Spiro- gyra. L. Rabenhorstii parasitizes the cells of Spirogyra, Mesocarpus, Mougeotia. L. pygmeum lives in the pollen grains of diverse species of Pinus. BIBLIOGRAPHY OF OOMYCETALES ATKINSON, GEORGE F.: Damping Off. Bull. 94, Cornell University Agricultural Experiment Station, May, 1895; Notes on the Occurrence of Rhodochytrium spilanthidis Lagerheim in North America. Science, new ser., xxviii: 691-692, Nov. 13, 1908; Some Fungus Parasites of Alge. Botanical Gazette, xlviii: 321-338, November, 1894. CLINTON, G. P.: Oospores of Potato Blight, Phytophthora infestans. Report Conn. Agricultural Experiment Station. Part x, Biennial Report of 1909-1910: 753-774; Oospores of Potato Blight. Science, new ser., xxxill: 744-747, May 12, tort. CLAUSSEN, P.: Ueber Eientwicklung und Befructung bei Saprolegnia monoica. Ber. d. Deut. Bot. Gesellsch., xxvi: 144, 1908. Coker, W. C.: Another New Achlya. Botanical. Gazette, 50: 381-382, November, IQgIo. Davis, BrAptry M.: Cytological Studies on Saprolegnia and Vaucheria. The American Naturalist, xlii: 616-620. OOMYCETALES [19 pe Bary, A.: Comparative Morphology and Biology of the Fungi, Mycetozoa and Bacteria, 1887: 132-145. DucGGAr, BrenjJAMIN M.: Fungous Diseases of Plants, 1909: 135-173. ENGLER, ApDoLr, and GiLc, ERNst: Syllabus der Pflanzenfamilien, 7th Edition, IQI2: 38-42. Hoiper, Cuas. F.: Methods of Combating Fungous Disease on Fishes. Bull. of the Bureau of Fisheries, xxviii: 935-936. Jones, L. R., Gropincs, N. J. and Lurman, B. F.: Investigations of the Potato Fungus, Phytophthora infestans. Bull. 168, Vermont Agricultural Experiment Station, August, 1912. Kerner, ANTON: The Natural History of Plants, 1895, ii: 668-672. Maenus, P.: Kurze Bemerkung iiber Benennung und Verbreitung der Urophlyctis bohemica. Centralblatt f. Bakteriologie, Parasitunkunde u. infektions- krankheiten, ix: 895-897, 1902; Ueber eine neue unterirdisch lebende Art der Gattung Urophlyctis. Ber. der Deutschen Bot. Gesellschaft., xix: 145- 153, 1901; Ueber die in den Knolligen Wurzelanswiichsen der Luzerne lebende Urophlyctis, do., xx: 291-296, 1902; Erkrankung des Rhabarbers durch Perono- spora Jaapiana, do., xxviii: 250-253, IgIo. Me uvs, I. E.: Experiments on Spore Germination and Infection in Certain Species of Oomycetes. Research Bull. 15, Agricultural Experiment Station, June, IQIt. Miyake, K.: The Fertilization of Pythium de Baryanum. Annals of Botany, XV: 653. PETERSEN, HennrtNG E.: An Account of Danish Fresh-water Phycomycetes, with Biological and Systematical Remarks. Annales Mycologici, viii: 494-560, 1910. ROSENBAUM, J.: Studies of the Genus Phytophthora. Jour. Agric. Res. 8: 233-276, with pls. 7 and key, 1917. SPENCER, L. B.: Treatment of Fungus on Fishes in Captivity. Bull. Bureau of Fisheries, xxviii: 931-932, 1910. STEVENS, F. L.: The Fungi Which Cause Plant Disease, 1913: 66—-1or. Trone, A. H.: On the Fertilization of Saprolegniee. Annals of Botany, xviii: 541. VON TAVEL, F.: Vergleichende Morphologie der Pilze, 1892: 5—25. Wacer, H.: On the Fertilization of Peronospora parasitica. Annals of Botany, X1V: 263, IQ00. WETTSTEIN, RrcHarD R.v.: Handbuch der systematischen Botanik, 1911: 158-160. WILson, Guy West: Studies in North American Peronosporales V. A Review of the Genus Phytophthora. Mycologia, vi: 54-83, March, ror4. Zirzow, Paut: A New Method of Combating Fungus on Fishes in Captivity. Bull. of the Bureau of Fisheries, xxviii: 939-940, 1910. Zopr, WILHELM: Die Pilze, 1890: 282-313. Wacer, H.: On the Structure and Reproduction of Cystopus candidus. Annals of Botany, x: 295, 1806. CHAPTER XIV HIGHER FUNGI The higher true fungi are characterized by a mycelium in which the hyphe, as arule, are permanently multicellular by the formation of trans- verse septa dividing the hyphal length into short cells. Some mycolo- gists, among them Brefeld, think it important to call the fungi which are transitional between the PHycomyceTes and the MycomycetrEs proper by the name MESOMYCETES, but the distinction between these intermediate forms and the higher fungi, being at times difficult to make, the writer has thought it best not to use the name MESOMY- CETES, as that of a subclass. The student will see the justice of this viewpoint as the discussion proceeds. Of unsatisfactory position in the fungous system are two families of fungi, which Brefeld includes in the subclass MESOMYCETES, which will illustrate his point of view as to transitional forms. Under HEMIASCINE&, as a suborder, he includes the families ASCOIDEACE& and ProtoMyceETACE&. Engler considers that these families have a doubtful systematic position. They show affinity to the PHYCOMY- -CETES, and yet, they have septate hyphe and a sporangium, known as an ascus, which contains an indefinite number of spores, hence their closer affinity to the fungi of the order ASCOMYCETALES. The first family is represented by Ascoidea rubescens which lives on wounded beech tree trunks, particularly in the sap which flows from the wounds. It forms a brown felt-like growth. The richly septate hyphe cut off laterally and terminally conidiospores and sporangia are formed in a series, so that as the numerous derby-hat-shaped spores are dis- charged and the sporangium is emptied of its contents a new sporangium forms inside of the walls of the old one, so that ultimately a sporangium may appear to arise out of a receptacle with a wall composed of three or four layers. In old cultures, the fruit-bearing hyphe may be united to form Coremia. The genus Dipodascus belongs to this family. The 120 HIGHER FUNGI [21 family PROTOMYCETACE is represented by the genera Prolomyces, Monascus and Thelebolus. Protomyces is a genus of fungi parasitic in the higher plants; for example, P. macrosporus lives in UMBELLI- FER&, P. pachydermus in Taraxacum. The coprophilous fungus Thelebolus stercoreus lives on the excrement of rabbits. It has a large rounded sporangium surrounded by a cushion of hyphe. Numerous spores suggestive of the moulds are formed within this sporangium. ORDER III. ASCOMYCETALES.—The fungi of this order are characterized by a mycelium which lives either saprophytically, or parasitically, with animals or plants. It has with few exceptions a rank, or exuberant, development sometimes with apical growth. The hyphe are septate and the cells are uninucleate, or plurinucleate. The reproduction of the majority of species is through endogenous spores known as ascospores, which are formed in definite numbers, usually eight, sometimes less (four, two, one), and sometimes more (sixteen, thirty-two, sixty-four, etc.) inside of a sporangium known throughout the order as an ascus (aoxos = wine-skin, water bottle). Frequently, they are called sac fungi, because of the sac-like ascus. The asci are found either isolated, or more generally, they are in fruit bodies where the asci are usually arranged along with the paraphyses between them in definite layers, which may be termed ascigeral. The paraphyses may assist in the discharge of the spores, but more usually their func- tion is that of packing in which they serve also for the protection of the adjacent asci. The fruit body is an apothecium, when it is open with the ascigeral layer wholly exposed. Such apothecia may be platter-like, saucer-shaped, cup-shaped, or goblet-shaped, and either sessile, or stalked, the length of the stalks being a variable character. The perithecium is a closed fruit body sometimes produced under ground where it remains subterranean. It may be entirely closed with no opening (cleistocarpous), or it may open by a pore at the top. This pore may be borne directly at the top of the rounded perithecium, or the perithecium may be drawn out into a larger, or a shorter neck, so that it becomes flask-shaped, or bottle-like. A narrow canal may lead through the neck, which may be straight, or variously curved. Sometimes the paraphyses, which extend through the neck and out of the pore, are designated periphyses. As accessory fruit forms, we find the conidiospores, which are of various forms, and which are borne singly, or in chains, at the ends of vertical hyphz (conidio- E22 : MYCOLOGY phores), or they are inclosed fruit bodies with terminal pores known as pycnidia (pycnidium), and in such the conidiospores are termed pycnidiospores, or pycnospores. The hyphe also break up into a disconnected series of spores known as chlamydospores, or the whole of the hypha set aside for reproductive purposes may break up into a connected series of spores, the oidiospores. Where the conidiophores are united together into strands, a coremium is formed. Sclerotia, or condensed masses of resting hyphe, are not unusual in the order. Certain ascomycetous fungi are lichen fungi, as they are parasitic on green alge and with them form the lichen thallus, which bears a certain nutritive relation with the organic or inorganic substratum, so that we may distinguish the crustaceous, foliose and fruticose kinds of lichen thalli. Where such lichen fungiand others of the order ASCOM Y- CETALES live on the surface of bark, they are epiphleoidal; where beneath the surface, hypophleoidal; where they live on rock surfaces, they are epilithic; in rock holes, hypolithic; and on the surface of the earth, they are epigeic; below the surface, hypogeic. The growth on — the surface of animals is ectozoic, in animals endozoic. The growth on | the surface of leaves and other plant parts is designated epiphytic or — epiphyllous; inside the plant, as endophytic, or endophyllous. Zoospores are never formed in any of the fungi of the order. A few areaquatic. — That sexuality exists in forms of the ASCOMYCETALES has been © determined only recently and these discoveries confirm the views of de Bary, who claimed that the process existed in this order, although Brefeld and his disciples claimed the contrary. Thanks to the epoch- making research of R. A. Harper, seconded by that of Claussen, J. P. Lotsy, Baur, Darbishire, Guillermond and others, the fact that sexuality exists has been proven indubitably. The first type displayed — by Pyronema, Boudiera and related genera is where a multinucleate — carpogonium with a trichogyne is fertilized by a multinucleate antheridium. A uninucleate antheridium unites with a uninucleate oogonium in the ErystpHAcE&. ‘The sexual organs are more or less reduced in many genera and in some of the ASCOMYCETALES, they are wanting completely. In the development of the sexual organs and in the behavior of the egg-cell, there is represented here a type of sexual reproduction which has its closest parallel in the red alge (RHODOPHYCE). There isa suggestive similarity between the structure of the sexual organs and the process of development q a HIGHER FUNGI 123 following fecundation in Spherotheca, Pyronema and Collema, and in such red alge as Batrachospermum, Nemalion and Dudresnaya. A sketch of the process will not be amiss. The antheridia and oogonia arise in Pyronema from the apical cells of thick hyphal branches, which arise vertically from the substratum. These organs stand side by side. Soon a trichogyne is formed on the oogonium, as a papillar outgrowth, and subsequently it is cut off from the oogonium proper by a transverse wall. The antheridium and oogonium are multinucleate from the start and a broad stalk cell is cut off from the base of the oogonium. ‘The tip of the trichogyne curves over to meet the tips of the antheridium, and the wall between them is dissolved enough to form a pore by which the cytoplasm of one organ becomes continuous with the cytoplasm of the trichogyne in which the nuclei have already disintegrated. The antheridial nuclei migrate into the trichogyne, and while this is happening the nuclei of the oogonium move to the center, where they become collected into a dense, hollow sphere. Now the basal wall of the trichogyne breaks down and the antheridial nuclei pass into the oogonium and become mingled with those of the egg cell. The antheridia and carpogonial nuclei now become paired without fusing. Out of the oogonium grow ascogenous hyphae and the paired nuclei pass into them. The young ascus develops from a penultimate cell of a bent ascogenous hypha with two nuclei which fuse, after the ascus has been formed and this fusion represents a sexual process. The end cell of the ascogenous hypha and the stalk cell are uninucleate, and these two cells may fuse to form a binucleate cell out of which a penultimate cell may arise. This single nucleus of the ascus then divides to form the series of eight ascospores usually found in the ascus. The synapsis stage of this single nucleus is immediately followed by a reduction division. Claussen! has found that the formation of the ascus is not as simple a process, as described by Harper, and he has added materially to our knowledge by his reinvestigation of Pyronema confluens (Figs. 38, 39 and 40). He finds that the conjugate nuclei do not fuse in the asco- gonium (carpogonium), nor in the ascogenous hyphe, nor in the pen- ultimate cell, nor when the tip cell of the ascogenous hook fuses with the stalk cell to form a binucleate cell. He finds that the penultimate 1 CLAUSSEN, P.: Zur Entwickelungsgeschichte der Ascomyceten, Pyronema con- fluens. Zeitscrift fur Botanik, 4, Jahrgang, Heft: 1-64 with 6 plates. 124 MYCOLOGY cell may proliferate a new hook with penultimate, tip and stalk cells d Fic. 38.— Diagrammatic representation of the observed methods of Ascus formation. (After Claussen, Zur Entwicklungsgeschicte den Ascomy- ceten, Pyronema confluens, Zeitschr. fiir Botanik 4 Jahrb., 1912.) and this another, and during this process of proliferation, the nuclei derived by descent from the antheridial nuclei remain distinct from those of the ascogonium (carpogo- nium). Even the two nuclei derived from the tip and stalk cells show this dif- erence, and their descendants remain distinct with the pro- liferation of a new hook with stalk cell. The series of ac- companying figures taken from (the “paperasbyaere: Claussen will enable the student to understand the process better than alengthy description. The antheridia and oogonia of Spherotheca arise as lateral branches of neigh- boring myceliai filaments. The oogonium is cut off from the rest of the hypha by a transverse septa, and pos- sesses a single nucleus. The antheridial branch appears quite nearits base and grows 4 upward pressed closely to the side of the oogonium. The antheridial cell with one nucleus is also cut off by a transverse septum. ‘This nucleus now divides and one of the two nuclei passes into the attenuated end of the HIGHER FUNGI [25 antheridium, which is cut off by a partition wall. The walls . between the two organs are dissolved and the male nucleus passes through the opening formed wanders toward the egg nucleus with which it fuses. Immediately after fertilization, the oogonium begins steady growth, and some of the outer cells formed become the cover Fic. 39.—Diagrammatic representation of the development of the ascogenous hyphal system. (After Claussen.) cells of the perithecium. But ascogenous hyphe are formed, which contain two nuclei, then four nuclei by division with karyokinetic figures. Two of the nuclei wander to the curved side and this is cut off by two partition walls to form the binucleated penultimate cell, which becomes the mother cell of the ascus. The two nuclei of the 126 | MYCOLOGY The fusion or nucleus then divides to form those of the eight ascospores, and the walls of the perithecium grow to inclose the asci thus formed, including the paraphyses, which develop between the asci. All of the typic ASCOMYCETALES have uninucleate hyphal cells, while the ascogenous hyphe are binucleate, and in this case the nucleus has a double chromosome number. Hence is suggested an alternation of generations. The life cycle of Pyronema may be displayed in a graphic form beginning with the ascospore and ending with its production again. The diploid, or twenty-four chromosome condition, may be repre- sented by the double lines. This life cycle is contrasted with the well-known one of the fern where a well-marked alternation of genera- ascus now unite. tion is shown. ‘ FERN (After Claussen) PYRONEMA Spore Spore Prothalluim Mycelium *® a PA Ss Antheridium Archegonium Antheridium Ascogonium Spermatozoid Egg cell He = | | Antheridium Ascogonium Sperm nucleus Egg nucleus (Sperm) Nucleus (Egg) Nucleus i | Sporophyte Ascogenous hyphe i Spore mother cell As DRAIN 4 Spores | Uninucleate ascus ye vax 4 Nucleate ascus Brown, in his studies of Leotia, has shown that the asci are formed at the tips of the ascogenous hyphe in several different ways (Fig. 41). In some cases, to quote him, “a hypha forms a typical hook, HIGHER FUNGI 27 Fic 40.—Diagrammatic representation of the development of the ascogenous hyphal system and of the mature ascus. (After Claussen.) 128 MYCOLOGY LAE 25 Fic. 41.—9, Vegetative hyphe giving rise to storage cell; 10, paraphyses grow- ing out from storage cells; 11-14, fusion of nuclei in storage cell; 15, 16, nucleus with two nucleoli in storage cell; 17, large storage cell with single very large nucleus; 18, storage cell with very irregularly shaped nucleus; 19, storage cell containing one large and two small nuclei; 20, an irregularly shaped storage cell; 21, 22, tip of as- cogenous hypha with two nuclei; 23, two nuclei in tip of hypha have divided to four; 24, walls have come in, separating sister nuclei; 25, hook in which there is no wall cutting off uninucleate ultimate cell; 26, hook in which two nuclei have fused to HIGHER FUNGI 120 consisting of a binucleate penultimate and a uninucleate ultimate and antepenultimate cell. In this case, the two nuclei of the penultimate cell may fuse to form the nucleus of an ascus, or they may divide and give rise to four nuclei of another hook. The uninucleate ultimate cell usually grows down and fuses with the antepenultimate cell, after which the nuclei of the two cells may give rise to the nuclei of another book or they may fuse to form an ascus. The walls separating the nuclei may fail to be formed without affecting the fate of the nuclei. In this process there is a conjugate division comparable to that in the rusts. Frequently the ascogenous hyphe do not become markedly bent, and in this case, when the two nuclei in the tip divide, a wall may separate two pairs of sisters. Either of these pairs may divide and give rise to the nuclei of another hook or fuse to form the nucleus of anascus. Any of the methods described above by which the number of asci is increased may be repeated many times. Large storage cells are formed in rows which give rise to the paraphyses. They are at first multinucleate but the nuclei fuse as growth proceeds. This process continues until often the cells contain a single very large nucleus many times the size of the largest nucleus in the ascus. The nuclei are very irregular.” Biackman, V. H. AnD Fraser, H. C., Jr.: Fertilization in Spherotheca. Annals of Botany, 19: 507-569, 1905. Brown, W. H.: The Development of the Asocarp of Leotia. Botanical Gazette, 50: 443-459- Ciaussen, P.: Zur Entwickelung der Ascomyceten Boudiera. Bot. Zeit., 68 (1905): Zur Entwickelungsgeschichte der Ascomyceten Pyronema confluens. Zeitschrift fir Botanik, 4 Jahrgang, Heft 1: 1-64; Ueber neuere Arbeiten zur Entwickelungsgeschichte der Ascomyceten. Ber. der. deutsch. Bot. Gesellsch. Jahrg., 1906, Band xxiv: 11-38 with complete bibliography. ENGLER, A. AND Gitc, Ernsv.: Syllabus der Pflanzenfamilien, 1912: 47. form nucleus of ascus, and tip has fused with stalk of hook; 27, ultimate cell has fused with antipenultimate; nucleus of latter has migrated into former, which is growing out to give rise to ascus or another hook; 28, two nuclei of penultimate cell have fused to form nucleus of ascus; ultimate cell has fused with antepenultimate and nucleus of latter has migrated into former, which has grown out to form another hook; 29, binucleate penultimate cell has given rise to hook; ultimate cell has fused with penultimate, and the two nuclei have fused; ultimate cell has not developed further; 30, binucleate penultimate cell has formed ascus, which fusion product of ultimate and antepenultimate has given rise to second ascus; 31, diagram illustrating multiplication of number of asci by method shown in 26-30; 9-20 X1I400. 21-30 X 2100. (After Brown, William H., The Development of the Ascocarp of Leotia. Botanical Gazette, 50: 443-359, Dec., I9t0o.) 9 130 MYCOLOGY Fraser, H. C. J. AND Wetsrorp, E. T.: Further Contributions to the Cytology of the Ascomycetes. Annals of Botany, xxii (1908). GUILLERMOND, A.: La quest. d.l. sex chez. 1. Asc. et les. rec. trav. Rev. gen. de- Bot., xx (1908): Recherches Cytologique Saxonomique sur les Endomycetes. Rev. gen. de Bot., 21: 353-393; 401-419 (1909) and a number of papers on the same subject in vol. 20. Harper, Ropert A.: Die Entwicklung der Peritheciums bei Spherotheca Cast- agnei, Ber. d. Deutsch. Bot. Gesellsch., 13: 475-1895; Kerntheilung und freie Zellbildung in Ascus Jahrb. f. wiss. Bot., 30: 249-284, 1897; Cell Division in Sporangia and Asci. Annals of Botany, 13: 467-524, 1899; Sexual Repro- duction in Pyronema confluens and the Morphology of the Ascocarp. Annals of Botany, 14: 321-400, 1900. Mortrer, Davin M.: Fecundation in Plants. Publ. 51, Carnegie Institution of Washington, 1904. Sanps, M. C.: Nuclear Structure and Spore Formation in Microsphera alni. Trans. Wisc. Acad. Sci., 15; 733-752; Botanical Gazette, 46:70. Warp, H. MArRSHALL:: Fungi, Encyclopedia Britannica, r1th Edition. WETTSTEIN, RICHARD R.v.: Handbuch der systematischen Botanik, 1911: 169-172 CHAPTER XV SAC FUNGI IN PARTICULAR (YEASTS, ETC.) Suborder A. Protoasciinez.—The fungi of this suborder are charac- terized by the absence of definite fruit bodies, that is the asci are not enclosed, but are free and at the ends of hyphe. Usually they are of unequal length. Four is the typical number of ascospores in each ascus. Theseare one-celled and may increase in number by gemmation. Famity 1. ENDOMYCETACE&.—This family is a small one of four genera of saprophytes and parasites. The two species of the genus Podocapsa are parasitic on Mucorace&, Eremascus albus, the single species of that genus grows on spoilt malt extract. The genus En- domyces with five species is represented by the cosmopolitan Endo- myces decipiens, which forms a snow-white parasitic growth on the toadstool Armillaria mellea. Its hyphe are branched richly and the asci are pear-shaped and borne singly at the ends of the branches, each producing four helmet-shaped ascospores, 6 to 8u broad and 5u high. Conidiospores are more frequently formed than ascospores. Oidiospores are also found, as well, as chlamydospores. Oleina nodosa and O. lateralis are the two species of the fourth genus. The first grows in olive oil. FAMILY 2. ExoAScACE#.—This family includes parasitic fungi which cause abnormalities of more or less marked character of the leaves, fruits and branches of mostly woody plants. The malforma- tions are in the nature of witches’ brooms of the smaller branches, leaf curls, and deformed fruits, such as the plum pocket. Stone fruits are especially subject to attack and in some cases the stone formation is suppressed entirely. The mycelium may be deep-seated and perennial, or it may be subcuticular, or sometimes found growing between the epidermal cells, as in Magnusiella flava, while in other forms, the hyphe may be below the epidermis and grow throughout the leaf tissue. The asci are generally formed on the surface of the host breaking through from the more deep-seated mycelium beneath. They are generally stalkless and arranged in close proximity to each 131 132 MYCOLOGY = other without paraphyses, so that they form a velvety layer’ on the — surface of the host plant. Eight ascospores are generally found, as in — the genus Exoascus, but in Taphrina (Taphria) the number may be increased considerably by budding, so that the whole ascus will be G Fic. 42.—Exoascus and Taphrina. A-—F, Exoascus pruni, A. Appearance on diseased twig; B, cross-section of diseased fruit; C, mycelium in tissues of host; D, young asci; EZ; mature ascus with spores; F, germination of spores; G, E, Exoascus alnitorquus; H, Taphrina aurea, ripe and unripe asci; J, Taphrina Sadebeckii. See Die naturlichen Pflanzenfamilien I. 1, p. 159. crammed full of them (Fig. 42). The ascospores are generally ellip- soidal and always one-celled with colorless, yellow, or orange contents. The perennial mycelium is responsible for the formation of witches’ brooms ina variety of trees and woody plants. Most of them are the SAC FUNGI IN PARTICULAR 133 result of the parasitism of species of Exoascus. The ‘hexenbesen” are brush-like, or tufted masses of branches, which suggest the presence of other plants (like the mistletoe) parasitically or epiphytically growing. They result mainly by the infection of a bud which de- velops a branch with increased growth. On this branch, all dormant buds are stimulated to activity and the whole infected system of branches consists of negatively geotropic branches. These brush- like excrescences are called the thunder-bushes, and are sometimes nest-like in appearance. An anatomic study shows that the parenchy- matous tissues—pith, hypodermis, etc.—are greatly increased; wood and bark are traversed by abnormally broad medullary rays, the ducts have short members, the wood fibers wide lumina, which are sometimes thin-walled and septate. The bast fibers are few, or entirely wanting. The cork cells are enlarged and retain their protoplasmic contents a longer time. The form of the witches’ brooms are various. Many of them are pendent, some are nest-like, owing to the death of some of the branches. In some the branches are elongated, while some have short twigs. The end of the original branch from which the lateral branches developed usually dies and its food substances are absorbed by the hypertrophied branches. The family includes three genera, distinguished, as follows: A. Asci found at the end of intercellular mycelial branches. 1. Magnusiella. B. Asci developed on a more or less subcuticular ascogenous mycel- ium. (a) Asci eight- (exceptionally four-) spored. 2. Exoascus. (b) Asci many-spored by gemmation of the spores. 3. LTaphrina. The genus Magnusiella comprises five species, four of which are found in Europe and two in America. Magnusiella flava forms+small pale yellow specks on the leaves of the gray birch, Betule populifolia in North America. The genus Exoascus includes about thirty species arranged in two subgenera, the first of which includes those species which deform fruits, which form witches’ brooms, and the second those which cause a spotting of the leaves of various plants. It would lengthen this book unduly to enumerate all of the species of Exoascus with an account of the deformities of branches and fruits which they produce. Only a few of_the more important species will be enumerated here, 134 MYCOLOGY and the diseases which they cause will be described later. Exoascus pruni (Fig. 42) is the cause of an important disease of plum trees, producing the so-called plum pockets. It also attacks Prunus domestica and P. padus in middle Europe, and P. domestica and P. virginiana in - North America. Exoascus communis attacks the fruits of several American species of Prunus among them P. maritima. Exoascus alnitorquus infests the pistillate spikes and cones of species of alder (Alnus), such as Alnus glutinosa and A. incana in middle Europe, and A. incana and A. rubra in North America, causing an enlargement of the fruit scales into twisted, tongue-like, reddish outgrowths. Exgascus deformans is the cause of peach-leaf curl. Exoascus cerasi is responsible for the formation of witches’ brooms on the cherry. The genus Taphrina causes witches’ brooms and leaf spots. Taphrina purpuras- cens attacks the leaves of a North American sumac, Rhus copallina, causing a puckering of the leaves with the formation of a reddish- purple color. 7. aurea (Fig. 42) forms yellow blotches on the leaves of several European and North American poplars, viz., Populus nigra and P. italica of Europe, and P. Fremontii, P. grandidentata and P. deltoides of North America. 7. Laurencia causes witches’ brooms on a fern in Ceylon, Pteris quadriaurita. Suborder B. Saccharomycetiineze.—A true filamentous mycelium is absent in the fungi of this suborder. The plants are single-celled and reproduce by budding, or gemmation. Occasionally under ex- perimental treatment where the culture media are varied, the cells develop into hyphe and together form a mycelioid growth. Spore formation consists in a single cell, developing one to eight spores. It, therefore, may be looked upon as an ascus and the spores are as- cospores. Many of them cause fermentation. FAMILY 1. SACCHAROMYCETACE2.—Many species of the genus Saccharomyces are called generically yeasts, and are of economic importance, because they induce the alcoholic fermentation of car- bohydrate substances. ‘The action is accompl shed through a soluble enzyme formed in the protoplasm of the yeast cell, and first isolated by: Buchner by grinding the yeast cells in sand and extracting the ferment zymase. The general shape of yeast cells is oval, ellipsoidal, and pyriform (Figs. 43, 44). The cell wall is well defined and consists of modified forms of cellulose which may be called fungous cellulose, because it does not react to the reagents used for true cellulose. This SAC FUNGI IN PARTICULAR 135 much can be said that the wall consists of a carbohydrate, probably some isomer of cellulose. Lining the inner surface of the cell wall is a layer of protoplasm which may be called the ectoplasm, which probably serves as an osmotic membrane. ‘The cytoplasm fills the rest of the cell with the exception of spaces occupied by the vacuoles of glycogen, nuclear vacuoles, oil globules, the nucleus and nuclear granules. The glycogen is gradually used up as it probably serves as reserve food, the same as starch in the higher plants. These glycogen vacuoles generally coalesce until one large vacuole may almost fill the cell, FIG. 43. Fic. 44. Fic. 43.—Yeast cell, Saccharomyces cerevisiae. (After Marshall.) Fic. 44.—Yeast, Saccharomyces cerevisie. 1-10, Young cells with nucleus, showing its structure; 6-8, division of nucleus; 11~13, cells after twenty-four hours’ fermentation with large glycogenic vacuole filled with lightly colored grains. (After Marshall, Microbiology, Second edition, p. 62.) the cytoplasm and nuclear bodies being pressed against the cell wall and forming a thin protoplasmic lining to the inner cell wall surface. Wager! in 1898 demonstrated the nuclear apparatus in a numberof yeast species. The nuclear apparatus consists in the earliest stages of fermentation of a nucleolus in close touch with a vacuole (Fig. 44, No. 4) which includes a granular chromatin network suggesting a similar struc- ture in the higher plants. The vacuole may disappear and then the chromatin granules are scattered through the protoplasm, or are gathered around the nucleolus, which is present in all of the cells, as a perfectly homogeneous body. Numerous chromatin vacuoles are often found 1 Wacer, Harotp: The Nucleus of the Yeast Plant. The Annals of Botany Xl: 409-539. 136 MYCOLOGY in young cells and these ultimately fuse to form a single vacuole which occurs in the cells during the earlier and the later fermentation. The process of budding is associated with the stretching of a network of nu- clear granules and its final constriction in the neck between the mother and the daughter cell. The nucleolus moves to the constriction where it becomes dumbbell- shaped, one half press- ing into the daughter cell (Figs. 44 and 45). There are no stages of karyokinesis dis- played, but by the sim- ple process described above the daughter cell receives approxi- mately one-half of the nuclear substance of MiGieAG. Fic. 46. Fic. 45.—Young yeast cells, Saccharomyces ellipsoideus, with nuclei and division of nuclei. (After Marshall, Microbiology, Second edition, p. 64.) Fic. 46.—Yeast, Saccharomyces cerevisie, the variety known as brewers’ bottom yeast; a, spore formation; b, elorigated cells. (After Schneider, Pharmaceutical Bac- teriology, Pp. 144.) the mother cell. In spore formation, the chromation which is scattered through the cytoplasm is absorbed more or less completely into the nucleolus which elongates and divides by a constriction in its middle part. Subsequent divisions result in the formation’ of four nucleoli around which protoplasm collects and thin membranes which become the walls of the ascospores which remain at first small, but later increase in size (Fig. 46). The formation of spores can be secured by taking ‘. SAC FUNGI IN PARTICULAR [37 a sterile block of plaster of Paris with a saucer-shaped hollow on top. This block is placed in sterilized water and the top is seeded with vigorous, young well-nourished yeast plants which develop spores if kept at 25°C., in from twenty-four to forty-eight hours. The tem- perature at which spore formation occurs and the time which it takes for sporulation are points which have been obtained by experimenta- tion for all the more important species of yeasts. The data which has been obtained is used in the physiologic diagnosis, or identification of the various kinds of SACCHAROMYCETACE, which react differently under experimental treatment. Film formation is also of diagnostic importance, where economic yeasts form floating films on the nutrient liquid media in which they are grown. The time required for the development of the film differs, other conditions being equal, with the species of the yeast and is longer the lower the temperature of the culture. Hansen obtained the following data for Saccharomyces cerevisia ; Film formation takes place at: 33° to 34°C. in about 9 to 18 days. Sa ieee Besa: in HBOUE ‘ ag Saccharomyces cerevi. o 02 oe De ae ated eee sie, showing repro- 13° to 15°C. in about 15 to 30 days. duction by germina- 6° to 70°C. in about 2 to 3 months. tion, or budding; a, : single cells; b, bud- No formation of film occurred above 34°C. orbelow ding cells. (After 5°C. Another point of importance is that species BN ie Mle ea of Saccharomyces form films so that this process is not entirely associated with the fungi belonging to the so-called genus Mycoderma. In fact some authors recognizing that Saccharomyces cerevisi@ (Fig. 47) produced films have named that yeast, Mycoderma cerevisi@, and have thus confused its identity. Hansen in a paper published in 1888 classified the yeasts essentially, _as follows: rt. Species which ferment dextrose, maltose, saccharose: Saccharo- myces cerevisi@ I, S. Pastorianus I, S. Pastorianus II, S. Pastorianus III, S. ellipsoideus I, S. ellipsoideus IT. 2. Species which ferment dextrose and saccharose, but not maltose: Saccharomyces Marxianus, S. exiguus, S. Ludwigiit S. saturnus. 3. Species which ferment dextrose, but neither saccharose nor maltose: Saccharomyces mali Duclauxii. 138 MYCOLOGY 2 4. Species which ferment dextrose and maltose, but not saccharose Saccharomyces n. sp. obtained from stomach of bee by Klécker. 5. Species which ferment neither maltose, dextrose nor saccharose: Saccharomyces anomalus var belgicus, S. farinosus, S. hyalosporus, S. membranifaciens. The general chemic phenomena associated with the formation of alcohol by fermentation out of sugar may be expressed by the formula: CeHi20¢6 = 2C2H,O + 2CO2 Alcohol Carbon dioxide The carbon dioxide passes off in bubbles as a gas, while the alcohol remains in solution. The most important yeast is the beer yeast Saccharomyces cerevt- si@ which is a unicellular plant of spheric or elliptic shape 8 to 12m long and 8 to to” broad. Sometimes the cells formed by budding remain connected to form a chain consisting of the mother, daughter, granddaughter and great-granddaughter cells. Spore formation is characteristic and the size of the spores varies from 2.5 to 64. ‘There are usually four spores in each cell. The following gives the tempera- ture conditions of spore formation in this species: At 9°C. no spores develop. At 11° to 12°C. the first indications are seen after 10 days. At 30°C. the first indications are seen after 20 hours. At 36° to 37°C. the first indications are seen after 29 hours. At 37.5°C. no spores develop. The temperature limits for film formation are 33° to 34°C. and 6° to 7°C. There are a number of races of the common beer yeast, which may be separated into the bottom yeasts and the top yeasts. The bot- tom yeasts are those which live within the liquid and mostly at the bottom even from the start. Some of these yeasts form spores with difficulty. The top fermentation yeasts are those which grow on the surface of the liquid and cause a brisk fermentation with a large amount of froth, or head, as exemplified by the Munich lager-beer yeasts. Yeasts are among the oldest of cultivated plants, as in biblical times leavened (yeast-raised) and unleavened bread were known. The leaven was a lump of dough kept from one baking to the next. Un- leavened bread was simply flour mixed with water and baked, and as a result, a hard tough bread was obtained. The use of yeast as a SAC FUNGI IN PARTICULAR 139 starter began in Roman times, but the art was lost until the seventeenth century, when it was regained. One of the earliest methods of obtain- ing yeast was salt raising, which consisted in adding to a quantity of milk a little salt sufficient to delay the growth of bacteria, while the yeast found entrance to the milk through the air and grew rapidly. This milk was then mixed with dough for the raising process. Bakers also sometimes used a brew called barms. Scotch barms were prepared by taking hops and flour with other ingredients which were allowed to Fic. 48.—Saccharomyces ellipsoideus. A common yeast in jams, jellies, etc. Budding process is shown in many of the cells as also the vacuoles. Fig. 66, p. 145, Schneider, Pharmaceutical Bacteriology, 1912. ferment spontaneously, and the fermented material was used in bread baking (see page 667). Saccharomyces ellipsoideus (Fig. 48) is known as the wine yeast and may be classed as.a wild species, while the beer yeast is found only in cultivation. The vegetative cells are ellipsoidal 6y long, single, or united into a row of loosely connected cells. The cells are two- to four- spored. The spores are spheric 2 to 4u broad. It is important in the fermentation of grape juice, gaining entrance from the skin of the grape fruit upon which it lives. In the spore form, it overwinters in the soil, being blown as dust to the developing grape fruits. The E40 _ MYCOLOGY bouquet, or flavor of the wine seems to be due to the variety of wine yeast used in the fermentation of the juice, for every wine-producing region seems to have its especial form of wine yeast and the growth is different. Some yeasts, such as those of Burgundy and Champagne, form a compact sediment, which quickly settles leaving the liquid clear, while others remain for. a long time suspended and settle slowly. Saccharomyces ellipsoideus IT is a very dangerous disease yeast, produc- ing turbidity in the liquid of bottom fermentation breweries. Saccharomyces Pastorianus I was first discovered in the dust of a Copenhagen brewery and also in diseased beer. Its growth in wort consists of sausage-shaped cells. .S. Pastorianus II produces a feeble top fermentation. S. Pastorianus IIIT was found in bottom fermenta- tion beer affected with yeast turbidity. Saccharomyces ilicis and S. aquifolii were found on the fruits of the holly, Ilex aquifolium. Saccharomyces Vordemanni is similar in appearance to wine yeast, its cells being onion-shaped, or pear-shaped. It is present in Raggi, which is employed in Java in the manufacture of arrack. It forms 9 to 10 per cent. alcohol. : Saccharomyces pyriformis was discovered by H. Marshall Ward to be active in the formation of ginger beer in conjunction with Bacterium vermiforme, for when these organisms are added to a sugar solution containing ginger, an acid beverage with considerable head is formed known as ginger beer. Saccharomyces exiguus occurs in pressed yeast, and it is capable of ‘developing considerable alcohol from dextrose and saccharose solutions. Saccharomyces anomalus has been found in impure brewery yeast in Hungary, also in Belgian beer, on green malt, on bran, in syrup of Althea, in soil, and on plum fruits. It ferments wort readily forming a gray film, a turbidity in the liquid, and an odor like fruit ether. The spores are helmet-shaped, suggesting those of Endomyces decipiens, which is parasitic on the caps of Armillaria mellea,a toadstool. Saccha- romyces membranifaciens grows in a gelatinous mass on the injured roots of elm trees, in polluted water, and in white wines, where it destroys the bouquet of the wine. It completely consumes acetic and succinic acids, and quickly forms gray corrugated films on the surface of wort. The organisms of Kefir are Saccharomyces cartilaginosus and S. fragilis. Kefir is a beverage prepared originally in the Caucasus region by fer- SAC FUNGI IN PARTICULAR I4I menting milk. Kefir grains, which include the above yeasts, a Torula, and 3 bacteria (Bacillus caucasicus, etc.) are added to the milk as a starter. The fermentation of the milk results in the formation of alcohol lactic acid and carbonic acid. Mazum (Matzoon) an Armenian drink, is prepared by adding a white, fatty cheese-like mass, to milk. The starter includes colored yeasts Oidium lactis, mould fungi, a yellow Sarcina, Bacillus subtilis, some cocci, Bacterium acidilactici and Saccharo- myces anomalus. The only species of yeast, which can be recognized immediately by microscopic examination, is Saccharomyces Ludwigit, with its lemon-shaped vegetative cells, on the point of which a wart makes its appearance, which is cut off by a septum from the rest of the cell. This species is transitional to those included in the genus Schizo- saccharomyces. The form of Saccharomyces Ludwigit suggests S. apiculatus, which is unequally dumbbell-shaped. The genus Torala according to Hansen includes yeasts similar to Saccharomyces, but which do not form endospores, a typical mould growth, and which produce alcohol in all percentages. They are widely distributed in nature. Schréter in Engler’s ‘ Die natiirlichen Pflanzenfamilien”’ recognizes only two genera in the yeast family, namely, Saccharomyces and Mono- spora. The reproductive cells of the former have two to eight (seldom one to three) spores and the spores are spheric, or ellipsoidal, while the needle-shaped spores of Monospora are borne singly in reproductive cells, or asci. Hansen! considers Monospora to be a doubtful form of yeast (Saccharomyces douteux), as also the genus Nematospora. He recognizes the following genera: Saccharomyces, whose spores have a single membrane and the cells reproduce by budding; Zygosaccharomyces, where the asci are associated with conjugation; Saccharomycodes, whose spores have one membrane and sprout into a promycelium; Saccharo- mycopsis, whose spores have two membranes; Pichia with hemispheric or angular spores and Villia with citron-shaped spores. Lafar in his book on “Technical Mycology”’ (II, part 2, page 274) gives an analytic summary of the genera which he believes should be recognized. The position of such genera as Zygosaccharomyces, Saccharomycopsis, Schizosaccharomyces with respect to nearly related fungi is presented and discussed with a diagrammatic scheme of relationship by 1 HANSEN, E. Cur.: Grundlinien zur Systematik der Saccharomyceten. Centr. f. Bak., 1904. 142 MYCOLOGY Guillermond,! who suggests the probable evolution of such forms from Eremascus and Endomyces. Dr. H. Will discusses in Lafar’s book the family TorRuLACE&, species of which are widely disseminated on field and garden fruits and on plants of all kinds finding suitable condi- tions for their growth during the decay of these fruits, and during the technic processes of fruit preservation, such as the making of pickles and sauerkraut. A number of them will no doubt prove to be budding stages of other fungi for our knowledge of them is decidedly imperfect. The character of the so-called pink yeast, red yeast, and black yeast is even less well known. As they are budding fungi, some have even classed them with the genus Saccharomyces. The genus Mycoderma was created to include the budding fungi, which form true films and which are formed rapidly on nutrient liquids, particularly on beer and wine with air between the cells, which are usually short and sau- sage-shaped. They are strongly aerobic and form, when exposed to the air, a wrinkled skin on the surface of the liquid. Like the true wine yeasts, these various species of Mycoderma have their natural habitat in the soil and they are carried to their appropriate nutrient substances by insects, rain or wind. They are probably not true yeast plants, but may represent growth conditions of other fungi, as related to certain nutrient materials. Curious chemic activities are possessed by species of Mycoderma, for example, the formation of acids and their destruc- tion both at the same time. Citric and succinic acids for example are consumed by them. 1 GUILLERMOND, M. A.: Recherches Cytologiques et Taxonomiques sur les Endomycetees. Revue Generale de Botanique, 21: 401-419, 1909. CHAPTER XVI SAC FUNGI CONTINUED Suborder C. Plectasciineze.—This suborder includes fungi with a well-developed mycelium on which are developed either on the surface of the substratum or within it, as in the subterranean forms, closed perithecia without an opening at the top. The wall of the perithecium is sometimes called the peridium. The asci are developed on hyphe of irregular branching, and in considerable numbers, forming irregular layers of the perithecial interior. Each ascus is rounded and three- to eight-spored. The spores are one- to many-celled. Condiospores occur in a few of the forms, such as Aspergillus, Meliola and Penicillium. Many of the fungi of this suborder are saprophytic, but some are de- cidedly parasitic, as Thielavia basicola, which destroys the roots of pea plants by its parasitic growth and species of the families TERFEZIACEZ and ELaPHOMYCETACE#, the mycelia of which form mycorrhiza with roots of flowering plants. Economically, the suborder is interesting, because it includes the common blue and green moulds:and species of Aspergillus used in the fermentation industries. The fruit bodies of several kinds of Terfezia are used as food by the Arabs of North Africa, Arabia, Syria and Mesopotamia. FAMILy 1. GYMNOASCACE&.—The fungi of this family are of interest, because of the structure of their fruit bodies. In the genus Gymnoascus, the spheric asci arise on short lateral branches of hyphe which form a dense rounded mass inclosed by loosely branching hyphe, which form a basket-like inclosure of the ascus-bearing portion Gymnoascus Reesit is coprophilous. Some of the shorter branches of this outer envelop- ment are sharp-pointed and spiny. Ctenomyces serratus, the single representative of its genus, grows on decaying bird feathers. It has branches with short hook-like extremities. The fruit body in this fungus is similarly rounded and covered with hyphe that form an open basket-like peridium. Famity 2. ASPERGILLACEH.—This family includes fourteen genera, the most important of which aré Aspergillus, Penicillium and 143 144 MYCOLOGY Thielavia. ‘The perithecia are never subterranean. They are usually small, spheric, usually closed, and their walls are made up of pseudo- parenchymatous hyphe. ‘They rarely open by a pore, more usually they break up at maturity to allow the escape of the ascospores. The inclosed asci are spheric to pear-shaped and two- to eight-spored. The moulds of the genus Aspergillus (Figs. 49 and so) are usually saprophytic, and are found upon decaying vegetables, moldy corn and | other cereals. After the conidiospores are formed, the color of the mould develops and various shades of green, white, blackish-brown, brownish-yellow, brown and reddish are found in the different species of the genus. The recognition of this genus is made easy by the shape of the conidiophores, which are elongated unicellular (unseptate) and terminate in a globular swelling, the top of which is covered with a large -number of closely set stalks, or sterigmata, of variable length and shape on which the conidiospores develop. In the related genus Sterigmato- cystis, the sterigmata are branched (Fig. 51). The conidiospores are spheric, or ellipsoidal, always unicellular with smooth or granular walls, and are formed in long chains (concatenation) from each sterigma imparting the characteristic color to the whole growth. The perithecia are fragile spheres with thin walls which may be yellow (A. herbari- orum) dark red (A. pseudo-clavatus), or even black (A. fumigatus) in color. The perithecia and asci are unknown in many of the species, — so that the classification of the species cannot be based on the characters of that organ and of the ascospores. Only about six to ten species are known to have perithecia out of a possible total number of 120 species included in the genus. This number will probably be considerably reduced when these moulds are better known. The accompanying figures show some of the specific differences of the conidiophores and conidiospore production. The common green mould, Aspergillus herbariorum (= Aspergillus glaucus, Eurotium Aspergillus glaucus) grows on many substances such as dried plants in the herbarium, (hence its specific name), on old black bread (pumpernickel), on jellies, on jams, on old leather, on herring pickle and other objects of domestic use. At first the mycelium is white andas the young conidiospores begin to form it turns to a pale green, later becoming a dirty grayish green, while the feeding hyphe change color to a pale yellow and finally a brown color by the deposit of pigment granules. The globular part of the conidiophore is 604 across and crowded with simple sterigmata SAC FUNGI CONTINUED * T45 (7u by 14m), bearing prickly, spheric conidiospores 7 to 30u in diameter which are larger than any other well-known species. It produces perithecia also with readiness and in abundance.’ The at first pale brown-yellow perithecia, later brown, are about too to 200 in diame- ter in closing numerous asci which contain five to eight colorless smooth ellipsoidal spores, exhibiting a furrow directed longitudinally and 5 to 8u broad by 7 to row long. The perithecium develops gradu- ally from spirally coiled hyphe. The hyphe of the screw are divided Fic. 49.—Aspergillus oryze associated with yeasts in the making of the Japanese beverage Saké. Vegetative hyphe (a) and spore-forming hyphe (0, c, d) are shown. Fig. 71, p. 152. (Schneider, Pharmaceutical Bacteriology, 1912, 19.) transversely into as many cells as there are turns of the screw. The bottom hyphal cells of the screw send up two or three branches of irregular thickness which grow toward the apex. One of these branches looked upon as an antheridium grows more rapidly than the others and its contents serve to impregnate the inclosed carpogone. These outer erect hyphz then branch copiously to completely envelope the carpo- gone and the perithecial wall is thus formed. From the carpogone are now formed the numerous ascogenous hyphie, which branch plenti- 10 146 MYCOLOGY fully and bear terminally asci of a pyriform shape. These contain eight grooved ascospores. Aspergillus herbariorum, as a domestic and industrial fungus, is selective. It does not thrive on liquid sac- charine media with mineral salts and inorganic nitrogenous food, while black bread and wort gelatin are suitable media. Moderate tempera- tures (8 to 10°C.) are best for its growth, and it ceases growth entirely at blood temperatures. The temperature limits are 7° to 30°C. with optimum at 20 to 25°. It grows on tobacco, cigars, hops, cotton-seed meal, acid pickles, and smoked meats. It causes the blackening and spoiling of chestnuts and is found on the kernels of various nuts even before they are removed from the shell (see Appendix VII, pages 702 to72 1). The rice mould, Aspergillus oryzee (Fig. 49), is of practical impor- tance as a saccharifying fungus, and it has been cultivated for centuries by the Japanese and used by them in the preparation of the rice mash for Saké, as well as in the production of Miso and Soja sauce. It grows luxuriantly and is usually yellow-green in color turning brown with age with large closely set tough conidiophores about 2 mm. tall. The tops of its conidiophores are obovate, or spheric. The sterigmata are radially arranged producing yellowish-green spheric conidiospores (6 to 7m) in chains. The sterigmata are larger than in A. herbariorum 4 to 5u by 12 to 2ou. No perithecia have yet been observed. This mould secretes a very active diastase and it has been used in the making of pharmaceutic preparations, such as Taka diastase, which is used in the dose of 2 to 5 grains either in tablet, capsule or solution in cases of indigestion im- mediately after meals. It converts the starchy food into dextrin and sugar. The discovery of this diastase in Aspergillus was made by Takamine, a Japanese zymologist, and his product has been used over the civilized world. Aspergillus Wentii, which is readily kept in culture on glucose or beerwort agar, is used in the preparation of Tas Guin Java. It appears spontaneously on boiled soy beans that have been covered with leaves of Hibiscus and it causes a loosening and disintegration of the firm tissues of the bean. The growth of this species is of a pale coffee color with conspicuous conidiophores about 2 to 3 mm. in height, their thick brown heads up to 20opn in diameter are on pale smooth stalks. The end of the conidiophore is globular 75 to gou in diameter and is covered with slender simple sterigmata (4u by 15u) which bear small globular to elongated conidiospores, 4 to 5u diameter. The mycelium at first SAC FUNGI CONTINUED 147 ‘is snow-white; later it becomes reddish brown. The discovery of perithecia is yet to be made. Aspergillus flavus plays an important part in the cocoon disease of silkworms. The stipe portion of its conidiophore is roughened by colorless granules. Aspergillus luchuensis, according to Inui, is used in the preparation of a beverage Awamori, which resembles whisky and is used in the Loochoo islands. Aspergillus tokelaw is found in Tokelau, or Samoan disease, attack- ing the natives of certain of the Pacific islands. An important patho- genic species, which causes an epidemic disease of pigeons and lives in the human ear and the lungs of various birds, is Aspergillus fumigatus, which was the cause of a false tuberculosis of a calf in Philadelphia. An autopsy by Ravenel and the writer showed the lung tissue of the calf penetrated by the mycelial hyphe of the fungus, and its conidio- phores bearing the conidiospores in a fan-like manner were seen project- ing into the lung cavities almost completely filling them. It, therefore, grows well at blood temperature, and if its conidiospores are introduced into the arterial circulation of animals they germinate and produce serious illness, which may terminate fatally. It also acts injuriously in certain fermentation processes carried on at high temperatures as certain lactic acid fermentations. It attacks tobacco, decaying potatoes, bread, malt and beerwort. It has dwarf conidiophores o.1 to 0.3 mm. long, with club-shaped globules 10 to 2ou thick, upright sterigmata 6 to 15u long and with long chains of conidiospores (2 to 3). Nut-brown globular perithecia are found, 250 to 350 in diameter, in- closing oval thin-skinned asci (9 to 14) with eight red lenticular tough- walled spores (4 to 4.54). Asa parasite of the human skin it was called Lepidophyton. The green mould, which usually grows on malt, is Aspergillus clavatus causing a moulding of the substratum. The largest species of the group is Aspergillus giganteus, which looks at first super- ficially like a Mucor, but later owing to its grayish-green conidiospores it is readily separable from the mucor vegetation. Its sterigmata seem to be hollow, communicating with a pore-like opening with the center of the conidiophore. No perithecia have been found. Other species are A. nidulans (Fig. 50), which can be cultivated readily, A. varians and A. ostianus, the latter distinguished by an ochraceous pigment. The black mould Aspergillus niger more properly Sterigmatocystis niger 148 MYCOLOGY (Fig. 51) has a copious literature. Lafar cites forty workers of recent date, who have studied it. The physician finds it as an occupant of 3) 2092 53959S989S° Cet e5e5se ne o Cy \ etesst war AYE j) At é PY o CY ry Ie) ww. ee (? Fic. 50.—Aspergillus nidulans. A, Mycelium with conidiophores; B, branched conidiophore; C, spore chains at end of conidiophore; D, small conidiophores; E, young fruit showing development of covering; F, hyphe with swollen ends; G, hypha from interior of fruit-body; H, hyphe with young asci; J, developing perithe- cium. (See Die natiirlichen Pflanzenfamilien I. 1, p. 302.) the human ear in a disease otomycosis. It is associated with the cork disease which imparts a taste to bottled wine. It grows well in acid substrata, as gall-nut extract, tannic acid and has a decided capacity SAC FUNGI CONTINUED 149 for producing oxalic acid. It has stiff slender conidiophores several millimeters in height. The terminal part can be studied only after the bleaching or removal of the dark masses of conidiophores. Fic. 51.—Sterigmatocystis niger (Aspergillus niger) showing conidiophores and coni- diospore formation with stages in germination of spores. (After Henri Coupin.) The genus Thielavia is represented by a common pathogenic species, T. basicola, whose life history and pathogenic character will be de- 150 MYCOLOGY scribed later. It attacks the roots of a large series of plants including the tobacco, at least 105 species of plants being attacked according to the latest account.!. The parasitic mycelium is intercellular, abun- dantly septate and hyaline. It produces conidiospores, which are abjointed acrogenously from the conidiophore, and are not as was supposed formerly endospores formed by free cell division within an endoconidial cell. The first conidiospore is liberated by the differentia- tion of its walls into an inner wall and a sheath and by the rupture of the latter at its apex. The later conidiospores grow out through the sheath of the first and are freed by a splitting of their basal walls.? This same process is probably that of all “‘endoconidia”’ in fungi. FAMILY 3. ELAPHOMYCETACEZ.—The fruit bodies of the fungi of this family are subterranean with a distinct, mostly thick peridium whose surface is marked by a more.or less strongly developed rind. The asci borne within the closed fruit body are irregularly arranged and united into large groups, which are separated by radially arranged vein- like masses of sterile hyphe. The asci are spheric, or pyriform, and mostly eight-spored. The whole spore-bearing interior of the fruit body, when ripe, is transformed into a powdery mass with the sterile hyphe remaining as a number of capillitia-like threads. There is no spontaneous opening of the fruit body at maturity. The family in- cludes a single genus, Elaphomyces, which comprises about twenty-two species, found mostly in northern Italy, in Germany and France, a few in England, northern Europe and North America. Such species, as Elaphomyces papillatus, E. atropurpureus from the oak and chestnut woods of northern Italy, E. mutabilis with a silvery-white mycelium growing in the oak, beech and birch woods of northern Italy, France and Germany, E. citrinus with an orange-yellow mycelium, also from northern Italy, all have delicate thin rinds which become wrinkled when dry, and belong to the section Malacodermei. The section Sclero- dermei includes those species with compact brittle rind, which is not wrinkled when dry. Here belong EF. maculatus with strongly de- veloped, green mycelium, surface of fruit body blackish brown with greenish markings, found in the oak forests of northern Italy, French 1JoHNson, JAmMeEs: Host Plants of Thielavia basicola. Journ. Agric. Res., vli: 289-300, Nov. 6, 1916. 2 BRIERLEY, WILLIAM B.: The Endoconidia of Thielavia basicola; Zopf, W.., Vnnals of Botany, xxix: 483-401, with 1 plate, October, rors. SAC FUNGI CONTINUED ESi Jura and the Tyrol. J. cervinus, which is found under oaks, beeches and pines in Europe and North America, has a fruit body the surface of which is brownish yellow, or reddish brown, and is covered with numerous pyramid-shaped projections. The inner layer of the peri- dium of this species is not veined like FE. variegatus, another widely distributed species throughout Europe. The fruit bodies of the last two species are frequently parasitized by Cordyceps ophioglossoides and C. capitatus (see ante, Fig. 21). ‘FAMILY 4. TERFEZIACEH.—The fruit bodies of the fungi of this family are more or less deeply subterranean, tuber-like, infrequently galleried (Hydnobolites). The fruit bodies differ from those of the preceding family in that the interior spore-bearing portion does not break down into a powdery mass, hence there is no so-called capillitium, and as in that family the fruit body does not open spontaneously. The terfas, or kames, of arid Mohammedan countries belonging to the genera Terfezia and Tirmania were known to the Greeks and Romans. The species of Terfezia are found under and associated with the roots of the herbaceous or shrubby forms of Artemisia, Cistus and Helian- themum. A North African terfa, Terfezia conis, is found in the moun- tain forests of pine and cedar and in the sands of Sardinia from March For iprils “The desert terfas include 7. Boudieri, T. Claveryi, T. Hafizi and Tirmania ovalispora. Duggar,! an American mycologist, has gathered these fungi at the base of Artemisia herba-alba found growing in the sandy soil of small oueds, or stream beds, in southwestern Algeria. They are located by the breaking of the soil surface and are dug out by the Arabs with a pointed stick. They form a valuable food, as they are rich in protein. FAMILY 5. TUBERACE#.—General reference has been made to the members of this family in a description of the special ecology of the EUMYCETES. The mycelium of the truffles is well developed and septate, producing mostly subterranean, tuber-like fruit bodies, which have more or less numerous chambers lined with the ascigeral tissue supported by sterile hyphe. The asci, which are arranged irregularly in the ascigeral tissue, are one to eight-spored. The ascospores are unicellular, and in the truffles (Tuber) usually spiny. The mycelium is subterranean and is connected with the roots of coniferous and broad-leaved trees forming the so-called mycorrhiza. The simplest 1 Duccar, B. M.: Mushroom Growing, 1915: 207-217. MYCOLOGY KH mn bdo Ree ae je =~ eo SA S = Fic. 52.—A, Tuber estivum fruit-body; B, Tuber magnatum fruit-body; C, Tuber brumale f. melanosporum, section through fruit-body; D, Tuber excavatum, section of fruit-body; E, Tuber estivum f. mesentericum, piece of fruit-body near pceridium en- larged; G, piece of Tuber excavatum enlarged; H, Tuber rufum, fruit-body magnified showing asci and ascospores; J, Tiber brumale, ascia with spores; K, Tuber magnatum, _ ascus with spores. (See Die natiirlichen Pflanzenfamilien I. 1, p. 287.) SAC FUNGI CONTINUED 153 fruit body in the subfamily EUTUBERINE/ is found in Genea his pidula where it forms a hollow sphere with definite opening. Generally, it is provided with a system of tubes, passageways or galleries, which vary in their arrangement in the different genera. These galleries are hollow in some, in others filled with hyphe, constituting the vene externe. The sterile supporting hyphz between these passageways constitute the vene interne. In the subfamily BALSAMINACE#, the fruit body has a single, hollow chamber, or numerous hollow closed cavities. The ascigeral layers constitute the walls of these chambers. The fungi of the genus Tuber (Fig. 52) are of the most interest economically, as several species, such as 7. @stivum (Spring), T. brumale, T. melanosporum (Winter), 7. uwncinatum (Autumn), 7. rufum are edible, and are known as truffles (Fig. 52). These species occur in deciduous woods of north Italy, France and Germany and elsewhere in Europe. They are gathered for food by men (rabassier), who make a livelihood by selling the truffles for immediate use, or for canning purposes. As the fruit bodies emit a characteristic odor, they are located by the aid of specially trained dogs, and pigs, whose keen scent enables them to find the underground fruit bodies. As they are dug up, the animal is rewarded by his master with some other attractive morsel of food, and the newly discovered truffle is placed in a leathern pouch slung over the shoulder of the rabassier. The tin cans in which the truffles (Tuber melanosporum in Perigord mainly) are preserved for shipment to all parts of the world are usually labeled with a state- ment as to the contents of the can, and with a hunting scene, where the man and his truffle dog prominently figure. Near here should be placed the family MyriANGIACEAE repre- sented by the genus Myriangium with three species of wide distribu- tion. This family has been monographed by von Honel.! 1yon HOnEL: Sitzungsber. Math. Naturw. Klasse k. Akad. Wiss. Wien., 118, Abt. 1: 349-376, 1900. CHAPTER XVII MILDEWS AND RELATED FUNGI Suborder D. Perisporiinez.—The mycelium of the fungi which belong to this suborder is filamentous, superficial, light- or dark- colored, rarely forming a stroma. ‘The fruit bodies are superficial, spheric to egg-shaped without a pore and break up irregularly. Peri- thecia are usually dark-colored and in many cases surrounded by accessory hyphe, or suffulcra. The asci are spheric, egg-shaped, or elongated, and range within the closed perithecia from one to many in number. Paraphyses are usually absent. The following families are recognized: A. Perithecium spheric, poreless or breaking irregularly at the top. (a) Aerial mycelium white, perithecium with appendages or suffulcra; accessory spores belonging to the genus Oidium. 1. ERYSIPHACEAE. (b) Aerial mycelium absent, or dark-colored, perithecia without appendages or suffulcra, accessory spores not belonging to Oidsum. 2. PERISPORIACE. B. Perithecium peltate flat, opening at top by a round pore. 3. MICROTHYRIACEZ. FAmILy 1. ErysIPHACE2.—The fungi of this family are popularly called “white” or ‘powdery mildews.’”’ During the summer their conidial fructifications (Oidium) are found on hops, maples, peas, roses and vines imparting to the surface of the host a dusty appearance, due to the white conidiospores. Later in the summer, the globular dark brown, or black, perithecia appear and these are provided usually with appendages, or suffulcra, which are frequently branched in a way characteristic of the different genera of the family. The white mycelium upon which the fruit bodies arise is truly parasitic, for short haustoria are formed which pierce the wall of the epidermal cells, and swell out into a bladder-like form for absorptive purposes. The haus- 154 MILDEWS AND RELATED FUNGI 155 toria are confined to the epidermal cells in all of the genera of the family except Phyllactinia, which forms special hyphal branches which enter the stomata, penetrate the intercellular spaces of the leaves and finally send haustoria into the cells of the loose parenchyma. With the exception of these haustoria, the mycelium of the “powdery mildews”’ is entirely superficial. The conidial forms of the different fungi of the family were classified formerly under the name of Oidium, but with a more detailed knowledge of their life history, this name has been relegated to the synonymy. The conidiospores, which are formed in great numbers, are carried by the wind, or by snails in the case of Erysiphe polygoni on plants of Aquilegia and are capable of immediate germination on reaching the epidermis of a suitable host plant, the germ-tube penetrating the outer wall of some epidermal cell. True sexual reproduction has been discovered in some of the mildews by R. A. Harper, thus verifying the earlier observations of de Bary. Spherotheca Castagnei serves to illustrate the process. The oogonium and antheridium, which are formed where two neighboring hyphe approach, each contains a single nucleus. The cell wall between these organs is dissolved at the time of fertilization and the male and female nuclei unite and a fresh wall is laid down between the two organs. Now the wall of the future perithecium begins to form by the develop- ment of a number of upright hyphal branches around the oogonium, forming a pseudo-parenchymatous tissue, while other branches later absorbed grow into the interior of the developing perithecium, while the outer wall cells become flattened and darker in color. The fol- lowing growth takes place in Spherotheca, which develops only a single ascus. The carpogonium elongates, divides and a curved row of five or six cells is formed. The penultimate cell of this row contains two large nuclei, while the other cells of the row have one nucleus each. The young ascus develops from this penultimate cell in which the two nuclei fuse followed by a rapid increase in size of the ascus, which presses against the inner wall cells of the perithecium and absorbs them. The nucleus of the ascus finally divides three times, producing the nuclei of the eight ascospores, which subsequently are formed by free cell formation. From the half-grown perithecium there arise apical, equatorial or basal hyphe which grow out as the appendages, or suffulcra, which in Phyllactinia are acicular and bulbous at the base (Fig. 53), in Uncinula hooked at the apex and in Podosphera and Micro- 156 MYCOLOGY Fic. 53.—Mildew of chestnut leaves due to Phyllactinia corylei with ascus and perithecium to left. (Martic Forge, Pa., Nov. 2, 1915.) MILDEWS AND RELATED FUNGI 157 sbhera (Fig. 54) dichotomously branched. These appendages prob- ably assist in the distribution of the perithecium, serving to attach the perithecia to plants, if wind-borne, or to the bodies of insects by which they are carried to other plants. The number of asci found in a perithecium and the number and character of the spores in the asci vary generically (see Appendix VIII, pages 721-726). As the fungi of this family are especially suitable for systematic study, a key is given not only of the principal genera, but also of the Fic. 54.—Lilac mildew, Microsphera alni. A, Perithecium with appendages; B, perithecia showing asci (a); C, ascus with ascospores; D, conidiophore (cph), bearing conidiospores (c.s.); E, beginning of fertilization; anth, antheridium; car, carpogonium; F, later stage of fertilization showing the fusion of two nuclei (f). (From Gager with E and F after R. A. Harper.) principal species of the different genera. These keys (p. 721) have been taken from a monograph of the ErystPpHACE# by Ernest S. Salmon, pub- lished in 1900, as vol. ix of the Memoirs of the Torrey Botanical Club, to which the mycologic student is referred for detailed descriptions of the various species. The material for the systematic study is easily kept in the dry condition and the perithecium can be studied in situ on the dried leaf or other plant parts, and later treated with weak alcohol 158 MYCOLOGY to remove the air, washed and mounted permanently stained, or unstained in acetic acid with a ring of asphalt, or in glycerine jelly for a study of the asci and ascospores. For a study of the distribution of the haustoria and for a detailed examination of the sexual organs,! small pieces (2 by 4 qcmm.) of hop leaves on which mycelia of the mildew (Spherotheca) are found in various stages of development should be fixed in weaker Flemming’s solution, as described by Zim- mermann on page 178 of his ‘“‘ Botanical Microtechnique,” and then hardened in alcohol and carried through to paraffin. The sections should be cut 5 to 7.5u thick stained with safranin (one to one and one-half hours), gentian-violet (one-half to one hour), and orange G. (quickly), then treated with absolute alcohol, cleared in oil of cloves: and mounted in balsam. The material for systematic study should be handed to members of the class in mycology, mounted and then studied as unknowns by the use of the generic and specific keys given in Appendix VIII, pages 721-726. FAMILY 2. PERISPORIACE#.—The aerial mycelium of these fungi is superficial black, filamentous, or wanting, or rarely as a firm stroma. The perithecia are situated on the aerial mycelium, or on the stroma. They are black, +spheric, rarely elongated, poreless, or weathering ir- regularly at the apex and without appendages. The wall is mostly membranous, or brittle. The asci are clustered and mostly elongated. The shapes of the spores are various. Paraphyses are usually wanting, © and are present in only a few cases. The genus Scorias has been described incidentally ina foregoing page — (72). Itis represented in America by a single species, spongiosa, which lives on beech twigs and leaves associated with some species of wooly aphis, or on the ground where the droppings of the aphis in the form of honey-dew have collected. Its mycelium is greenish-black, much- branched, rigid, septate and the hyphe are glued together by an abundant mucilaginous substance forming a loose spongy mass, bearing an abundance of pyriform, coriaceous perithecia, which enclose narrow, thick-walled, eight-spored asci. Elongate pycnidia and perithecia are also frequently seen. FamILy 3. MicROTHYRIACEZ.—The mycelium of the fungi of this — family is superficial and dark in color. The perithecia are superficial | 1 Harper, R. A.: Die Entwickelung des Peritheciums bei Spherotheca Castagnei, Bericht. der Deutsch. Bot. Gesellsch., xiii, Heft. 10: 475-481, 1895. ee MILDEWS AND RELATED FUNGI 159 shield-shaped, unappendaged, black, membranous to carbonous formed of radiating chains of cells. The asci are four- ta eight-spored, short and associated with paraphyses. ‘Two fungi which attack the coffee plant are the most important pathogenic species of the family: hs F SM ahaa seb rgoar Fic. 55.—A-—D, Nectria cinnabarina. A, Stroma of conidia and fruit-bodies Of fungus; B, stroma in section; C, ascus; D, mycelium with conidiospores; E, F, Nectria ditissima; F, conidia layer; G, H, Nectria sinaptica; G, ascus; H, pycnidia-like layer. J, Nectria inaurita; K, Nectria oropensoides coremium. (See Die natiirlichen P flanz- enfamilien I. 1, p. 357.) Scolecopeltis aeruginea and Microthyrium coffe. There are twenty- one genera, and more than 300 species not well understood. Suborder E. Pyrenomycetiinze.—The mycelium is always present in these fungi. The perithecia are either located upon the substratum, 160 MYCOLOGY or in the substratum, and are mostly spheric. A wall (peridium) is present inclosing the clustered eight-spored asci which arise from the interior basal part of the perithecium. The perithecium opens by an apical mouth or pore and is either isolated or imbedded in a stroma which takes manifold forms. The formation of conidiophores and conidiospores varies in the different families and genera. Sometimes a distinct conidial layer is formed; at other times the conidiospores are formed in pycnidia. The suborder includes many saprophytic and para- sitic fungi found upon plants and animals. | FAMILY 1. HyPOCREACEZ.—The perithecium of these fungi is spheric and opens terminally by a definite pore. In color, it may be pale, sprightly colored, or colorless, never black. Hypomyces with sprightly colored perithecia arises from a thick crust-like stroma. It lives parasitic- ally on a number of different fleshy fungi. For example, Hypomyces lactifluorum transforms a species of Lactarius into a cinnabarred growth roughly resembling a toadstool and without gills, while the original color of the host is completely lost in the higher color produced by the parasite. oar Nectria without stroma has its peri- ae eee ne cane. thecia developed on the surface of the G. P., Rep. Conn. Agric. Exper. Stat, substratum. N.cinnabarinaisa par- 1903.) asite on various deciduous trees (Fig. 55). Its conidial form known as Tubercularia vulgaris produces flesh- colored eruptions through the barx of various host plants. ~ Nectria ditissima grows on the beech. Polystigma has a crust-like stroma on the leaves of trees of the genus Prunus, while Epichloe typhina con- fines its parasitic attack to grasses upon which it develops orange- yellow stroma. The genus Cordyceps consists of species which live MILDEWS AND RELATED FUNGI 1601 SS==eeSS Fic. 57.—A, Balansia claviceps on ear of Paspalum; B—L, Claviceps purpurea; B, sclerotium; C, sclerotium with Sphacelia; D, cross-section of sphacelial layer; E, sprouting sclerotium; Ff, head of stroma from sclerotium; G, section of same; H, section of perithecium; J, ascus; K, germinating ascospore; C, conidiospores pro- duced on mycelium. (See Die natiirlichen Pflanzenfamilien I. 1, p. 371.) If 162 * MYCOLOGY parasitically on insects and their larva and some in subterranean fungi. The mycelium kills the insect or larva and mummifies it. Out of the host grow conidiophores (/saria) in early stages of development, and later stalked stroma, in which on enlarged terminal portions the per- ithecia with asci and ascospores are found. C. militaris and C. cinerea occur on insects, or insect larvee. C. sinensis is found on caterpillars in eastern Asia, while C. ophioglossoides grows on the fruit bodies of species of Elaphomyces (see ante, page 70) (Fig. 21). Claviceps isa genus of fungous parasites found in the developing caryopses of various grasses. Itsconidialstage was formerly known as Sphacelia. Claviceps purpurea and C. microcarpa are important species and their life his- tories will be described in the third part of this book. As ergot, the sclerotia of Claviceps purpurea are used in medicine (Figs. 56 and 57). Fifty-seven genera and three doubtful ones are recognized and described in Engler’s Die natiirlichen Pflanzenfamilien. Famity 2. DoTHIpDEACE®.—This family comprises twenty-four genera among the most important of which is Plowrightia (Fig. 22) and Phyllachora. The fruit bodies of these fungi is spheric with definite mouth and without distinct peridium, as they are found imbedded in a black stroma. Plowrightia includes twenty species of fungi, which form stroma in the interior of host plants, and which break through to the surface, and form pimples in the center of which the opening to the perithecium is found. The spores are egg-shaped, two-celled, hyaline, or bright-greenish. Plowrightia ribesia is found on dried twigs of species of currants Ribes in Europe and North America. P. virgultorum occurs on brick in northern and middle Europe, P. Mezeret grows on dead branches of Daphne in middle Europe and Italy. P. insculpta is found on dried branches of Clematis vitalba in Bel- gium, France, Germany and Italy and P. morbosa is the cause of black- knot of the cherry and plum (Prunus) and will be described subsequently. Phyllachora is a large genus of some 200 species found mostly on the leaves of various plants; P. graminis is the commonest species of cos- mopolitan distribution on grasses and sedges. The warty spot of clover is Phyllachora trifolii. FAMILY 3. SORDARIACEH.—The perithecia in this family are superficial, or deeply sunken in the substratum and often break through at maturity. The stroma is usually absent, but when it occurs the perithecia are sunken with projecting papilliform beaks. The perithecia MILDEWS AND RELATED FUNGI 163 are thin and membranaceous to coriaceous, slightly transparent to black and opaque. The asci are usually very delicate, surrounded by long paraphyses, or intermingled with them. The dark-colored spores are one- to many-celled, surrounded by a hyaline gelatinous envelope, or ornamented with hyaline gelatinous spicula. The SORDARIACE are entirely saprophytic and grow on manure, hence, they are coprophilous fungi. Special mechanical devices are shown by the asci for eruptive spore discharge and the distance to which the spores are shot may be between 5 and 9 cm.' Famity 4. CH&TOMIACE#.—This is a small family of two genera, Chetomium and Bommerella, which are found on waste paper, manure and on small living fungi, which resemble the fungi of the family Perisporiacee, if the mouth to the perithecium is wanting. Bom- merella has three-cornered ascospores. The perithecia of such forms as Chetomium spirale and C. crispatum are provided apically with masses of spirally wound ha’rs. FAMILY 5. SPHARIACEX.—This important family includes parasitic, or saprophytic fungi showing exceptional diversity on dead parts. They have rounded perithecia with definite opening. The peridium is evident, mostly dark-colored, membranous to leathery never fleshy, usually free from the substratum, or more or less depressed. A stroma may or may not be present. Some authors include a number of families which perhaps may be subordinated here and ranked as subfamilies. Rosellinia quercina is a disease of oak seedlings. Myco- spherella fragarie is the cause of leaf spot of strawberry; M. strati- formans produces leaf-splitting blight of sugar cane. Guignardia Bidwellii is a most important parasite, being responsible for the black rot of the grape and G. vaccinii causes cranberry scald. Apple scab and pear scab are due to the attack of Venturia pomi and Venturia pyrina. A serious disease of sycamore leaves in the spring known as anthracnose is caused by Gnomonia veneta. Famity 6. VALSACEZ.—The stroma of these fungi is black and is formed in the substratum which is more or less altered. The peri- thecia have a regular border and take various forms in the different genera. The asci are cylindric and long-stalked, alternating with paraphyses. Pycnidiospores are formed in pycnidia and conidiospores 1 GriFFITHS, DAvip: The North American SorDARIACE”%. Memoirs of the Torrey Botanical Club, xi, No. 1, May 7, tgor. 104 MYCOLOGY on definite conidiospores. Of the ten genera of the family, the genera Valsa and Diaporthe are the most important. Both genera include about 400 species, which are most saprophytic in wood and the bark of woody plants. Valsa oxystoma is the cause of the disease and death of the branches of Alnus viridis in alpine regions; Diaporthe farinosa grows on the branches of the linden, T7/ia americana in North America and D. eucalypti on Eucalyptus globulus in California. FAMILY 7. MELOGRAMMATACE&.—The stroma are mostly like those of the genus Valsa and rarely like those in Diatrype. They are hemis- pheric and are formed beneath the bark and later break through to the surface, where they are more or less isolated. The perithecia are imbedded in the stroma. Conidial fructifications are formed on the surface of young stroma, or pycnidiospores are produced in pycnidia. The most important genus of this family is Endothia, which is repre- sented by the Chestnut-blight fungus E. parasitica, which lives in the cambium and inner bark of chestnut trees causing a final girdling of the branch and the death of the part beyond the girdled area. It has caused untold injury to the forest groves of America, where the chest- nut tree abounds, and its morphology and its ravages will be described subsequently. FAMILY 8. XYLARIACEZ.—The stroma of these fungi is developed strongly and is frequently upright and branched. The perithecia are borne in the branched club-shaped portions of the fruit bodies. Early in their growth the surface is covered with conidiospores. The ascospores are unicellular and blackish-brown. The genus Num- mularia, which includes forty species, is represented typically by N. Bullardi, which causes black charcoal-like eruptions on thick branches of the beech, Fagus. Ustulina, with nine species, includes U. vulgaris found on old stems of broad-leaved trees and Hypoxylon with about 200 species is confined mostly to damp wood and old tree stumps. Xylaria digitata, one of the 200 species of that genus, grows on old wood, and X. polymorpha on old tree stumps. This family completes the list of pyrenocarpous fungi. Suborder F. Discomycetiineze.—The discomycetous fungi have a filamentous mycelium. Reproduction is by the union of two hyphal branches either of similar size, or differentiated into oogonia and anthe- ridia. The fertilized egg cell either develops directly into an ascus, or it develops ascogenous hyphe from which the asci are formed. MILDEWS AND RELATED FUNGI 165 The apogamous formation of fruit also occurs in this suborder. The asci are united into definite, usually flat layers, which are in open fruit bodies known as apothecia. Conidiospores are also found in some of the forms and the conidiophores are of diverse character. The asci are usually eight-spored. The fungi of this suborder are either parasitic, or saprophytic in habit, and a few of the fleshy members of the family PrzizAcrE& are edible. FamiLty 1. HystTeRIACE&.—The apothecium is elongated and the opening is a long wide cleft between the approaching walls of the apothecium, so that the ascigeral layer is exposed at the time of the spore discharge. Some species of the genera Lophodermium and Hypoderma are dangerous parasites of leaves; for example, L. pinastri attacks pine leaves; L. nervisequum attacks the spruce tree; while Hypoderma brachysporum is found on the white pine, Pinus strobus. Such genera as Lophium, Hysterium, and Glonium include species which are sapro- phytic on bark and wood. FAMILY 2. PHACIDIACEZ.—The apothecium is rounded, seldom elongated and its walls are separated through a star-shaped opening, rarely a cleft-like opening, so that the ascigeral layer is fully open at maturity. The family includes such parasites as Nemacyclus niveus on coniferous needles; Rhytisma acerinum, which produces black tar- like blotches on maple leaves; and R. salicinum, which causes similar black areas on willow leaves. Several species of T'rochila are found on the leaves of different plants. FAMILY 3. PYRONEMACE%.—The fruit body is placed on fine hyphe or on a felt-like cushion of hyphe. At first it is spheric; later, it is flatly expanded. The hypothecium is occasionally feebly de- veloped, at other times it is stronglyso. The peridium is poorly formed, or entirely absent. The most interesting genus is Pyronema. P. confluens has a fruit body 1 mm. across, and of a yellow or reddish color. It is often found in spots where fires have been kindled in the woods. The structure of the apothecium and the method of its forma- tion following the sexual union of an antheridium and oogonium have been described by Harper! and the essential details have been given on a former page of this book (ante, pages 123 and 126). 1 Harper, R. A.: Sexual Reproduction in Pyronema confluens and the Mor- phology of the Ascocarp. Annals of Botany, 14: 231-400, 1900 106 MYCOLOGY FAmiIty 4. ASCOBOLACE#.—The apothecia of the fungi of this family are unstalked. They are superficial and grow up on manure. The peridium is mostly thin, or wanting, and the hypothecium, which is well developed, consists of rounded parenchyma-like cells. In Ascobolus, the ascospores are discharged from the asci by a squirting Fic. 58.—A, B, Lachnea scutellata. A, Habit; B, ascus with paraphysis; C, D, Lachnea hemispherica; C, habit; D, ascus with paraphysis; E, Sarcosphera arenosa habit; Ff, G, Sarcosphera coronaria; F, ascus; G, habit; H, Sarcosphera arenicola ascus with paraphysis. (See Die natiirlichen Pflanzenfamilien I. 1, p. 181.) action, and this is accomplished probably by the pressure of the cell wall upon the cell sap. The end of the ascus breaks open suddenly, the ascus collapses, and the eight spores are discharged simultaneously along with the cell sap. In Ascobolus, which is related to Pyronema, the ascogonium is at first multicellular, but all the cells empty their MILDEWS AND RELATED FUNGI 107 contents into a single large one, from which the ascogenous hyphw then arise. FaMILy 5. PrzizAceE#.—The apothecia of this family are saucer- or cup-shaped, sessile or stalked, arising from a mycelium which is found in the substratum. The peridium and hypothecium consists of rounded cells and they are of fleshy, or leathery consistency. The asci, which are usually eight-spored, are separated by distinct para- physes. The spores are usually hyaline. Ldchnea and Peziza are the most important genera. Lachnea scutellata (Fig. 58) has a scarlet to vermilion-red cup, whose margin is beset with a fringe of —e » ADS Fic. 59.—Saucer-shaped fruit-bodies of Pezizarepanda. (Photo by W. H. Walmsley). large brown bristles. It grows on wet sticks and logs in damp, or wet places, especially at the water’s edge. L. hemispherica has a cup 1 to 4 cm. wide with a bluish-white to gray disk and with brownish outside bristles which fringe the margin of the apothecium. It grows on much- decayed wood. Peziza aurantia, which is found in the fall in woods, and is edible, has a bright orange cup 1 to 5 cm. wide, powdery outside. At first, it is cup-shaped, then saucer-shaped and irregular. It is stemless, or nearly so. The spores are clear, elliptic and strongly netted. A woodland form, P. coccinea, is scarlet in color and suggests a wine glass in its stalked apothecium. P. badia grows on the ground in grassland and woodland, and is also edible. It has a 168 MYCOLOGY dark brown to paler brown apothecium, 1 to 4 cm. across and almost stemless. P. eruginosa is a stalked, green form whose mycelium pene- trates the wood of beeches and oaks and imparts to them a copper- green color, which makes it valuable for the manufacture of the famous “Tunbridge ware.”’ The attempt has been made to extract the pig- ment, or to manufacture it synthetically for use as-a shingle stain, but without much success. P. Willkommiiproduces on larch trees a disease known as larch canker. Other species of Peziza grow on bark (Fig. 59), horse and cow manure, and are, therefore, typically coprophilous. Famity 6. HELoTIACE#.—The apothecia in these fungi are super- ficial from the beginning and rarely arise by break- ing through the-substratum. Sometimes they de- velop from a sclerotium (Sclerotinia). In texture, they are waxy, leathery and thick, and stalked, or unstalked, smooth or hairy. The asci are eight- spored. The spores are round, elongated, or fila- mentous, and one to eight-celled, hyaline. The paraphyses are filamentous. The fringe cup, Sarcoscypha floccosa, has a slender, white, hairy stem, 1 to 3 cm. long by 2 to 3 mm. wide, and bearing an apothecium 4 to to mm. wide with a scarlet disk, so that the whole fruit body is goblet- shaped. ‘The outside of the cup is covered densely with long white hairs forming a fringe at the margin. The spores are clear and elliptic 20 by 114. The Fic. 60.—Sclerotinia fringe-cup fungus grows on decaying twigs from oem um. (Afler sring to autumn. Sclerotinia is the most impor- tant genus economically. It includes about forty species. Theapotheciumarisesfromasclerotium. Sclerotinia baccarum forms sclerotia in the fruits of Vaccinium myrtillus; S. urnula (Fig. 71) in those of Vaccinium vitis-idea. Sclerotinia Fuckeliana forms sclerotia onthe grape-vine. Itsconidial form was long known as Botrytis cinerea. Sclerotinia sclerotiorum (Fig. 60) is parasitic and pathogenic ona number of cultivated plants, such as beets, and bears its sclerotia forming on the, subterranean parts of these host plants. The black disease of hyacinth bulbs is connected with the growth of Sclerotinia bulbosum. Apples, pears and stone fruits are attacked by S. fructigena. S. libertiana. causes lettuce drop. 5S. trifoliorum is responsible for the stem rot of MILDEWS AND RELATED FUNGI 109 clover. Other fungi without sclerotia are parasitic and destructive. Such are Dasyscypha Willkommiu, the cause of larch canker. D. Warburgiana is parasitic on cinchona in the tropics. Such genera as Coryne, Helotium, Lachnum and Ruistremia are saprophytic on wood. Famity 7. Moiiisiace#.—The fungi of this family differ from those of the preceding largely in texture, the former being tougher with hyphal cells modified in a fibrous manner. The spores are hyaline. Pseudopeziza is the only important germs with its apothecium formed beneath the epidermis, which is subsequently ruptured with the pro- trusion of a shallow fruit body. The asci show eight unicellular spores. Pseudopeziza medicaginis is the cause of alfalfa leaf spot. Ps. ribis causes anthracnose of currants. The remaining families of the suborder are Family 8, CELIDIACEs, Family 9, PATELLARIACE2, Family 10, CENANGIACEZ. Suborder G. Helvelliineze.—This suborder includes fungi with a well-developed mycelium which is filamentous and largely functional for nutritive purposes. From this mycelium, which penetrates the substratum, arises a fleshy, waxy or gelatinous fruit body, which usually possesses a stalk upon which is raised an expanded portion; sometimes club-like, in other forms constituting a distinct pileus. The expanded part, which may be smooth and gelatinous, wrinkled or with variously contorted folds, or of deep pits separated from each other by anastomos- ing ribs, is covered with the ascigeral layer, which consist of asci and paraphyses standing on end-like palisade tissue. The asci are typically eight-spored, rarely, two-spored, and open at the apex through the removal of a lid, or through a tube-like mouth. The ascospores are unicellular, or multicellular. FaMILy 1. GEOGLOSSACEZ.—The fruit body is fleshy, waxy, or gristly, and is separable into a stalk, or stipe, and an enlarged fertile portion, the pileus, which is club-shaped or knobbed, and its color is some shade of yellow, green, or black. The asci are club-shaped, opening by a pore at the apex. This family includes twelve genera, and it has been carefully monographed by Massee.! Geoglossum hirsutum is an American ground form with pileus flat and black, 2 to 3 cm. long and 1 to 2 cm. wide. It is wrinkled and hairy (Fig. 61). The stem is 6 to 8 cm. tall, black solid and hairy. 1 MAssEE, GEORGE: A Monograph of the Geoglossee. Annals of Botany, ii; 225-306 with 2 plates, 1897. 170 MYCOLOGY The spores are brown, very long and many-celled, too to 120 by 4 to au. G. glutinosum, another American species, grows on the ground among the grass. It is black and smooth with the ascigerous portion one-third the entire length of the fruit body and in shape oblong- lanceolate, slightly viscid. The upper portion passes imperceptibly into the stalk. The spores are eight in number, arranged parallel to each other with obtuse ends and three-septate, 65 to 75 by 5 to 6un, and brown in color. Leotia chlorocephala is a fungus found in West Virginia, New Jersey and Pennsylvania. It is cespitose in habit and grows in mixed woods on moist ground, from July until late frosts. It is green and_has a gelatinous appearance. The pileus is depressed globose, more or less wavy and with an incurved border, in color a dark verdigris-green. It is edible. Another species, L.lubrica, is found on the ground in woods from North Carolina and Minnesota to Massachusetts. Itis yellowish, olive- green with an irregular hemispheric, inflated, wavy cap. FAMILY 2. HELVELLACEZ.—The fruit body in these edible fungi is Fic. 61.—Geoglossum hirsutum. fleshy and divided into a hollow stalk A, Appearance of fungus; B, asci with i paraphyses; C, spore. A, natural and ascigerous expanded portion. ies goody Gazols: (Dic maler~ “The upper part is capslike and covered externally by the ascigeral layer. The asci are club-shaped and open by the lifting off of a distinct lid. The spores are ellipsoid, colorless, or bright yellow and smooth. Five genera are included in the family: Morchella, Gyromitra, Verpa, Cidaris and Helvella. ‘This family includes the largest of the sac fungi. Some species of Gyromitra weigh over a pound and forms of Morchella may growafoot tall. The cap of Morchella is more or less deeply ridged, crosswise and lengthwise and has a delightful odor. The broad stem Morel, Morchella crassipes, has a cap 4 to to cm. tall and 3 to 6 cm. wide at the base, in color tan to tan-brown, with deep pits and wavy to = SN a = CJ i — HH MILDEWS AND RELATED FUNGI 17] irregular ridges, the whole cap being more or less conic. The stem is 3 to 12 cm. by 2 to 6 cm., white and hollow. The spores are elliptic, clear, smooth, 20 to 22 by 10 to 124. M. esculenta, the common Morel, has a cap 3 to 7 cm. tall and 2 to 4 cm. wide, of a yellowish- brown to brown color, covered with very regular ribs with a blunt edge. The spores are smooth, elliptic, clear, 14 to 22u by 8 to ru. It grows on the ground in woods and forest openings, and is a delicious morsel. Gyromitra has a more irregular cap more or less inflated and folded, the edge united in places with the stem. G. esculenta has a rounded lobed pileus, irregular, gyrose-convolute, smooth and bay-red. Its stem is stout, stuffed, or hollow. The ascospores are elliptic, yellow- ish, 20 to 22u long. It grows in wet ravines, or springy places in the vicinity of pine groves, or pine trees. G. brunnea is brown in color and is figured by Clements in his “‘ Minnesota Mushrooms,” page 143. Verpa digitaliformis grows on ground in woods. It has a brown, or dark brown, smooth, bell-shaped cap with a long finger-like stem, beneath, hence the specific name. Verpa bohemica is the “ribbed verpa”’ and is delicious eating. The cap in the genus Helvella hangs loosely over the stem and it is saddle-shaped more or less lobed. The stem is ribbed. The ascigeral layer is confined to the upper side of the cap. All of the species are edible. Helvella crispa is a common species and has been collected in West Virginia, Pennsylvania and New Jersey. It is white or whitish in color, while H. /acunosa is gray to almost black. FAMILY 3. CyTTARIACE&.—This family is represented by the single genus Cyttarza with a tuber-like stroma in which the apothecia are sunken. ‘The stroma, which arises on the antarctic beech, Notho- fagus, in South America and Tasmania, is stalked. The asci are cylin- dric and eight-spored. The spores are ellipsoidal and hyaline. The paraphyses are filamentous, breaking down into mucilage. The cylin- dric asci bear elliptic hyaline spores. Six species have been described from Patagonia, Tasmania and Terra del Fuego. FaMILy 4. RuIZINACE&.—The fruit bodies of the fungi of this small family are stalkless and they are fleshy and waxy in consistency. Four genera are included. Suborder H. Laboulbeniineze.—We owe our knowledge of these eccentric or singular fungi to four botanists: J. Peyritsch, G. Lindau, 72 MYCOLOGY Roland Thaxter and J. Faull. They are parasitic on insects, mostly beetles, which live in moist situations and are long-lived and _ hiber- nating. They are often highly specialized, as to the parts of the insect on which they grow, occurring only on certain joints of the legs and on certain legs of the host. The vegetative mycelium is very much reduced, consisting of one to a few cells, which are attached to the body of the insect and their usually minute size renders them difficult of study. The host is not destroyed nor even inconvenienced by these fungi which appear as minute, usually dark-colored, yellowish bristles or bushy hairs projecting from the chitinous integument of the insect. Stigmatomyces Beri lives parasitically on house flies. The bicellu- lar spore with its mucilaginous coat becomes attached at its lower end. The upper cell develops an appendage which bears a number of unicel- lular flask-shaped antheridia from which the naked spermatia are shed. The lower cell divides into four cells which represent the female repro- ductive organ, where the carpogonium, or egg cell develops a trichogyne to which the spermatia become attached. The three fundamental parts of which these plants are composed are a main body, the receptacle; one or more spore-producing portions, the perithecia; and lastly, one or more appendages which, in the majority of cases, are associated with the formation of the male sexual organs. The receptacle is that por- tion of the fungus on which the appendages together with the perithe- cia, or their stalk cells, are inserted. The sterile appendages, which form dense tufts and sometimes are more conspicuous than the main plant itself, serve to protect the delicate trichogyne which is subse- quently developed. Sometimes, the primary appendage develops a spine-like process. The male organs and male elements in the LABout- BENIACE may be designated as antheridia and antherozoids, the former consisting of a single antheridial cell or a group of such cells, the latter of a single naked, or thin-walled cell, so that the antherozoids are pro- duced either endogenously or exogenously. Among the antheridia which produce endogenous antherozoids we may distinguish the simple and the compound. A simple antheridium discharges its antherozoids through its special pore or opening, the compound an- theridium consists of several antheridial cells each of which dis- charges its contents into a common cavity from which they es- cape. The female organs are formed from a segment of the lower cell of the receptacle rarely from the terminal cell. The perithe- MILDEWS AND RELATED FUNGI 173 cium, as in many other Ascomycetales, originates from a cell of the receptacle situated below the female organ. The procarp consists of three distinct parts: the trichogyne, the trichophoric cell and the part lowest the carpogenic cell, which is fertilized and undergoes further development. Faull! has shown in two species of Laboulbenia that after the procarp is mature the carpogonium and trichophoric cell become continuous. Meanwhile, the nucleus of the carpogonium is succeeded by two which are apparently daughters of the carpogonial nucleus, and almost simultaneously the trichophoric nucleus undergoes division. Later, a uninucleate trichophoric cell and a uninucleate inferior sup- porting cell are septated off from the now four-nucleated fusion cell. After further nuclear divisions a binucleate superior supporting cell and sometimes a binucleate inferior supporting cell are cut off. The binu- cleate ascogonium now begins to bud off asci, or divides into two asco- genic cells, each of which contains a pair of nuclei. Up to this stage no nuclear fusions have been observed. The nuclei of an ascogenic cell divide conjointly, a daughter of each passing into a young ascus. This process is repeated at the birth of every ascus. The pair entering the ascus soon fuse. The fusion nucleus divides by a reduction mitosis after a period of growth and the number of chromosomes is the same as in other mitoses. There are two other mitoses prior to spore forma- tion, and both are homotypic. The spores are delimited by the method characteristic of the ordinary sac fungi. Each ascus in Stigmatomyces Beri produces four spindle-shaped bicellular spores. In other genera eight two-celled spores are formed. It is to be noted in closing that the sexual organs of these curious fungi are similar to those of the red seaweeds, FLoRIDEH. Thaxter? has done more than any other botanist to make this order known systematically. Phylogeny of Ascomycetales—Atkinson in a philosophic discussion of the phylogeny of the Ascomycetales suggests six series or lines of development and his suggestions are incorporated in the accompanying chart. 1. Apocarp line from Dipodascus-like forms and by reduction. 1Fautt, J. H.: The Cytology of the Laboulbeniales. Annals of Botany, Xxv: 649-654, July, rto11. The Cytology of Laboulbenia chetophora and L. gyrinidarum. Annals of Botany, xxvi: 355-358, with 4 plates, April, 1912. * THAXTER, ROLAND: Contributions toward a Monograph of the Laboulbeniacee part I, 1896; part IT, 1908, Mem. Amer. Acad. of Arts and Sci. 174 MYCOLOGY 2. Plectocarp line from Dipodascus-like forms, perhaps similar to Monascus. 3. Perispore line arising from Monascus-like prototype, before split- ting of archicarp, or from ASPERGILLACEZ. 4. Pyrenocarp line arising near Monascus-like prototype, LABouL- BENIALES side near base, and some of the MycoTHYRIALES as reduced from SPHARIALES. Those who adhere to the belief that the AscomyctTALEs have descended from the red alge interpret their belief in three ways: first, sac fungi with highly developed trichogyne of the Collema type with cer- tain red alge of existing forms; second, sac fungi with highly developed trichogyne of the Polystigma type with hypothetic alge with trichogyne representing the common original stock of both groups; and third, sac fungi with simple generalized copulating gametes of the Gymnoascus type with hypothetic alge having a simple procarp representing the stock from which both groups started. . It will be noted that Atkinson believes that the fungi of the AscomycETALES have been derived from the simple PuycomycetTEs, and that the PROTOASCOMYCETES are der:ved by descent and degeneration from such a primitive form as Dipodascus, Endomyces Magnusii being the nearest known form to the generalized condition seen in Dipodascus. ‘The EvAScoMYCETES are derived from fungi similar to Monascus and Gymnoascus with generalized archicarp. Six distinct lines as previously noted arise from these primitive forms. Atkinson gives a chart which is purely provisional, and which suggests the probable relationship of the principal groups to each other and toa probable common ancestor. GENERAL BIBLIOGRAPHY OF THE ASCOMYCETALES Arxinson, Gro. F.: Phylogeny and Relationships in the Ascomycetes. Annals of the Missouri Botanical Garden, ii: 315-376, February—April, 1915. BARKER, B. T. P.: The Morphology and Development of the Ascocarp in Monascus, with 2 plates. Annals of Botany, xvii: 167, 1903. BLACKMAN, H. H. and Wetsrorp, E. J.: The Development of the Perithecium of Polystigma rubrum. Annals of Botany, xxvi: 761, 1912, with 2 plates. Brown, Horace T.: Some Studies in Yeast. Annals of Botany, xxvili: 197, 1914. CARRUTHERS, D.: Contributions to the Cytology of Helvella crispa, with 2 plates. Annals of Botany, xxv: 243, I19It. ‘ Ctements, F. E.: Minnesota Plant Studies: iv, Minnesota Mushrooms, 1910: 138-151. MILDEWS AND RELATED FUNGI Ty Conn, H. W.: Bacteria, Yeasts and Moulds in the Home, 1903, with 293 pages. Ducear, B. M.: Mushroom Growing, 1915, pages 188-224, dealing with European Truffles, Terfas and Morels. Exits, J. B. and Evernart, B. M.: The North American Pyrenomycetes, 1892, pages 793, with 41 plates. ENGLER, A.: Die Natiirlichen Pflanzenfamilien, I. Teil, 1 Abt.: 142-505 with separate parts by Ed. Fischer, G. Lindau and J. Schroeter. Faurt, J. H.: The Cytology of the Laboulbeniales. Annals of Botany, xxv: 649-654, July, tort. Fautt, J. H.: The Cytology of Laboulbenia chetophora and L. Gyrinidarum. Annals of Botany, xxvi: 325-355, with 4 plates, April, 1912. Fraser, H. C. I. and Uttsrorp, E. J.: Further Contributions to the Cytology of the Ascomycetes, with 2 plates. Annals of Botany, xxii: 331, 1908. Fraser, H. C. I. and Brooks, W. E. Sr. T.: Further Studies on the Cytology of the Ascus. Annals of Botany, xxiii: 537, 1909. Fraser, H. C. I. and GwyNNE-VAUGHAN Mrs. D. T.: The Development of the Ascocarp in Lachnea Cretea, with 2 plates. Annals of Botany, xxvii: 553, 1913. GRANT, JAMES: The Chemistry of Bread Making, 1912: 125-152. Grirritus, Davip: Phe North American Sordariacee. Memoirs Torrey Botanical Club, xi, tgot. JORGENSEN, ALFRED: Microérganisms and Fermentation, transl. 3d Edition by Alex. K. Miller and A. E. Lennholm, 1900, with 318 pages. Kout, Dr. F. G.: Die Hefepilze ihre Organisation, Physiologie, Biologie and Sys- tematik ihre Bedeutung als Girungsorganismen, 1908. Kiocker, AtB.: Fermentation Organisms: A Laboratory Handbook, transl. by G. E. Allan and J. H. Millar, 1903, with 391 pages. Larar, Dr. Franz: Technical Mycology, transl. by Charles T. C. Salter. II, Part I: 99-189: Part II: 191-481. MaAsseEE, GeorceE: A Revision of the Genus Cordyceps. Annals of Botany, ix: 1, with 2 plates. Masser, Grorce: A Monograph of the Geoglossee. Annals of Botany, 11: 225-301, 1897. MAssEE, GEORGE: The Structure and Affinities of the British Tuberacex, with 1 plate. Annals of Botany, xxiii: 243, 1909. MAssEE, GEORGE: Text-book of Fungi, 1906: 261-313. Satmon, E. S.: On Endophytic Adaptation Shown by Erysiphe graminis. Annals of Botany, xix: 444. Satmon, E. S.: On Oidiopsis taurica, an Endophytic Member of the Erysiphacee. Annals of Botany, xx: 187, 1906. Satmon, Ernest S.: A Monograph of the Erysiphacee. Memoirs Torrey Botan- ical Club, ix, 1900, pages 287, with g plates. STEVENS, F. L.: The Fungi Which Cause Plant Disease, 1913: 113-297, with bibliography. THAxTER, ROLAND: Contributions toward a Monograph of the Laboulbeniacee, part I, Mem. Amer. Acad. Arts & Sci., 1896; part IT, do., 1908. 176 MYCOLOGY THon, CHARLES: Cultural Studies of Species of Penicillium. Bull. 118, U. S. Bureau Animal Industry, roto. Wacer, Haroxp: The Nucleus of the Yeast Plant. Annals of Botany, xii: 499- 540, with 2 plates, 1898. Werrstern, Dr. RicHarp R. von: Handbuch der Systematischen Botanik (2d Edition), 1911: 168-192. CHAPTER XVIII BASIDIA-BEARING FUNGI (SMUTS) ORDER BASIDIOMYCETALES The fungi of this order have mostly a strongly developed mycelium, multicellular and at times with apical growth. Sexual reproduction is entirely absent, yet in the rusts, we find certain nuclear fusions which are looked upon by some mycologists as of a sexual nature. The characteristic method of reproduction is non-sexual by means of conidia, which in the most primitive forms are of indefinite number, while in the most highly differentiated forms the conidiospores are definite in number two to eight, and are borne on special conidio- phores known as basidia (basidium-ia). In many forms, the basidia are arranged in definite parts of fleshy fruit bodies and in special layers known as hymenia (hymenium-ia). Besides the conidiospores other kinds of spores, known as chlamydospores, are formed. Zoospores are entirely absent. The fungi of the order are either saprophytes, or parasites, and occasionally, they are facultative saprophytes, or faculta- tive parasites. None of them live in the water (nicht wasserbewohnend). The Basidiomycetales do not follow the Ascomycetales in the direct line of evolution of the fungi. They may be considered to parallel the sacfungi. The group issupposed, in this regard, to represent the results of extreme simplification; the sexual organs, if ever present, have in the phylogenetic history of these fungi long since disappeared and simple nuclear fusions function in all probability in lieu of the sexual act. Key TO SUBORDERS OF THE BASIDIOMYCETALES (AFTER STEVENS) Chlamydospores at maturity free in a sorus, produced intercalary, from the mycelium; basidiospores borne on a promycelium and resem- bling conidiospores. 1. Hemibasidii. Chlamydospores absent, or when present, borne on definite stalks. Basidia septate, arising from a resting spore, or borne directly on a hymenium. 2. Protobasidii. Basidia non-septate, borne on a hymenium. 3. Eubasidii. 12 diy 7 178 MYCOLOGY Suborder Hemibasidii—The conidiophore, or more correctly the basidium, arises from the chlamydospore and bears an indefinite and usually large number of basidiospores. All cells of the mycelium and the spores, as far as known, are unicellular. The position of this suborder in the family tree of the fungi is uncertain. The majority of the funguses are strictly parasitic on the higher plants, and their mycelia live in the tissues of the same, mostly as intercellular parasites, certain hyphe known as haustoria penetrating the interior of the host cells. Infection of the host takes place, as a rule, very early and in some cases at the time of seed formation, so that the parasitic mycelium keeps pace with the growth of the host plants and at definite times and places, such as anthers, ovaries and the like, which are mostly de- formed, the spore-bearing portion of the fungous parasite appears. The spores, which are formed in such places, are known as chlamydo- spores, and the mass of spores and diseased host parts are mostly black and soot-like. The chlamydospores give rise to a promycelium, which cuts off basidiospores. The basidiospores give rise either to conidiospores, or they infect some host plant, if deposited upon it at the susceptible time. Brefeld first suggested the name Hemibasidii for the UsTILAGINACE and TILLETIACE# which he considered as repre- senting the link connecting the lower fungi and the true BASIDIO- MYCETALES. Two families are recognized by mycologists, Sat USTILAGINACE and TILLETIACEZ. Famity 1. UstirAcrnAce®.—The fungi of this family are all para- sitic. They can be recognized readily by the outbreaks of dusty material that they produce on certain parts of their hosts, when they reach their reproductive stage. An important genus, Ustilago, the type genus of the family, derives its name from ustio, a burning. The smut. of wheat is called locally in England “bunt ear,” “black ball,” “dust brand” and “chimney sweeper.’’ All of these names are indica- tive of the sooty-black character of the spores. There are two chief phases in the development of a smut fungus, the mycelial phase and the spore phase. The hyphe of the mycelium mostly push between the cells through the intercellular spaces and form short special branches, or haustoria, which enter the host cells and absorb from them nutritive material. The mycelium may be localized, or it may be spread gen- erally throughout the host. Where the mycelium gains entrance to the host through the germinating seeds, it remains in the vegetative BASIDIA-BEARING FUNGI (SMUTS) 179 condition and without external manifestation of infection until in its fruiting stage, when it breaks through the tissues of the host, appear- ing at the surface. In perennial plants, the mycelium may live in the perennial parts, each year extending into the new growth. Eventually, the mycelium becomes conspicuous in certain organs of the plant. It may develop abnormal growths, or cause swellings in the stem leaves, flowers (anthers, ovaries), or fruits of the host. Here the hyphe break up into chains of spores, which develop thicker walls than the hyphal cells from which they arose and are known as chlamydospores (xAauis, xapvdos = acloak + oropa = aseed). The hyphal cells between the spores undergo almost complete gelatinization, which gelatinized cells are used probably to nourish the developing spores, as at maturity the spores lie loosely surrounded in part by the diseased cells of the host ready to be discharged as the adjoining hyphal and host cells dry up and completely disappear. The chlamydospores, which make up the smutty, or sooty masses, are usually thick-walled and, being small, 4 to 35u, they are easily disseminated. They are usually spherical, or spheroidal, but may be ovoid, ellipsoidal or even oblong. They are simple, 7.e., consisting of single cells, but they may be united into spore balls, which may have an external coating of sterile cells. The galls of the chlamydospores may be smooth, or echinulate, or reticulate with a network of ridges, or wings. Their color may be yellowish, reddish or olive-brown, violet, or purplish, and the dark-colored spores in mass may appear to be black or dark amber-brown. Sori are masses of the spores that break out singly, or in clusters, on the various organs of the hosts. These clusters are protected by their coverings of the tissue of the host. The sori may be dusty and easily broken up, while in other species, they may be hard and the spore mass is gradually disintegrated. The wind is undoubtedly one of the principal agents in the dissemi- nation of the smut spores, but it was found that no smut spores could be demonstrated in spore traps set up at the University of Manitoba by Buller farther distant from the infected fields than 250 yards. Man distributes the spores through unclean agricultural methods, such as using old grain bags over and over again, and in sowing seed to which the smut spores are attached. The threshing machine is an active agent in the spread of smut spores, and the farmer should see that his machine is carefully cleaned from one operation to another. 180 MYCOLOGY Fic. 62.—Germination of smut spores. 4, Chlamydospores; b, basidium; S, basidiospores; d, infection threads; e, detached pieces of mycelia; f, knee-joints. 1. Germination of Ustilago avene in 1/ 50 per cent. acetic acid 24 to 48 hours after being placed in liquid. 2. Same as in 1 but in distilled water. 3. Germination of Ustil- ago levis in Cohn’s modified solution at end of 24 hours. 4. Same as 3 but at end of 2or3days. 5. Germination of Ustilago tritici in Cohn’s modified solution. 6. Ger- mination of Ustilago strieformis from red top in 1/ 50 per cent. acetic acid at end of 2 days. 7. Same as 6 except in Cohn’s modified solution. (After Bull. 57, Univ. Til. Agric. Exper. Stat., March, 1900.) BASIDIA-BEARING FUNGI (SMUTS) 181 Experiments to determine the vitality of smut spores have shown that those of the stinking smut of wheat, covered smut of barley and oat smut are long-lived under favorable conditions for seven, or eight years, and ina dry condition are resistant to frost. Where vegetative reproduction occurs, as in the loose smuts, the spores lose their vitality after five to six months. It has also been determined that stinking smut spores passing through the bodies of animals lose their power of germination in a great majority of cases. Only those passing through pigs retain their vitality a longer time. The presence of occasional viable spores in the manurial offal of animals suggests a danger of the spreading of smut diseases through manure applied to fields as fertilizers. Germination (Fig. 62).—The spores, when placed in a drop. of water, send out a single hyaline thread several times the length of the spore, and this thread, or promycelium, becomes divided into four cells by cross-partitions, or septa. Usually the apex of these four cells produce one or more elongated thin-walled spores, the basidiospores, or sporidea. These basidiospores are pinched off at the base, and others are formed to take their place. When the basidiospores reach the proper host, whether in the seed, seedling, partly grown or mature condition, it forms on germination an infection hypha, which bores through the surface and enters the interior of the host. Once inside a mycelium is formed. Mopes oF INFECTION.—(1) Certain smut spores, as those of the stinking smut of wheat, covered smut of barley, naked and loose smuts of oats and others, adhere to the outside of the grains and are sown along with the grain. In the soil germination takes place and the spore produces a short stout mycelium, which develops secondary, or even tertiary spores, which by means of infection threads attack the young grain seedlings as they grow upward through the soil. This mode of infection is called seedling infection. (2) In the so-called loose smuts of wheat and barley, the chlamydospores, which are mature at the time of flowering of these commercial grasses, fall upon the female organs of the wheat, or barley, and germinating the infection hypha pushes its way into the developing grain where it remains dormant as a deli- cate mycelium. The normal development of the grain is not inhibited, so that when it is planted as seed, the mycelium begins to grow with the seedling and keeps pace with the future growth of its host until 182 MYCOLOGY the maturity of the spores at the time the wheat, or barley, come into bloom. This mode of infection is known as flower infection.