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Full text of "Diseases of plants induced by cryptogamuc parasites; introduction to the study of pathogenic fungi, slime-fungi, bacteria, and algae. English ed. by William G. Smith"

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DISEASES OF PLANTS 

INDUCED I;Y CRYnOGAMIC PAIIASITES 



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DISEASES OF PLANTS 

Induced by Cryptogamic Parasites 

Introdtictioii to the Study of 
Paihogenic Fungi, Slime- Fungi, Bacteria, & Algae 



BY 



Dr. KARL FREIHERR von TUBEUF 

PRIVATDOZENT IN THE UNIVERSITY OF MUNICH 

(English Orbition bii 
WILLIAM G. SMITH, B.Sc, Ph.D. 

LECTURER ON I'LANT PHVSIOLOGV 
UNIVERSITV OF EDINBURGH 



THREE HUNDRED AND THIRTY ILLUSTRATIONS 




LONGMANS, GREEN & CO. 

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AUTHOR'S PREFACE. 

In my research work, and in connection with my lectures at 
the University and Technical School of Munich, I have for 
some time felt convinced that there existed a very evident gap 
in the literature relating to the diseases of plants. There was 
need of a newer and more complete work on cryptogamic para- 
sites and the diseases induced by them on higher plants, a work 
furnished with many accurate illustrations, with a survey of 
the newer literature, and with a general part wherein parasitism 
and the relations between parasite and host are discussed from 
a botanical standpoint. Therefore, I have undertaken to write 
a book intended to supply in" some degree this pressing want. 
Here the attempt has been made for the first time to review 
in a general and comparative manner the biological, physiological, 
and anatomical relationships accompanying the phenomena of 
parasitism. Already De Bary has considered the varying degrees 
of parasitism and the phenomena of symbiosis in his celebrated 
Morpholo(ji) and Biology of the Fun/fi ; while AVakker has laid 
the foundations of our knowledge of the alterations in the 
anatomy of plants disea.sed by the agency of fungi, more especially, 
however, those alterations accompanying 'hypertrophy.' I venture 
to continue this difficult and comprehensive chapter of plant 
physiology, because for ten years I have devoted my time to 
the study of plant pathology. The book may l)e all the more 
acceptable since I have confirmed a large number of the 
observations and added the results of my own investigations, 
many of them now j)ublisbed for the first liinc. 

The jiresent time is fav(tural)le to my work. The gri'ut 
Syllof/c Farujorvm of Saccardo (with its a])pendices in Vols. IX. 
and X.) has been recently (•()m})l('te(l : the classic investigations 



vi author's preface. 

of Dret'eld iu the domain of mycology, and containing his 
classification of the fungi, are now well advanced; the Kryi^to- 
garnni-Flora of Kabenhorst is nearly completed ; and the newer 
literature and observations are now periodically reviewed in the 
Zcitschrift fur Pflanzenhratikheiten, and other magazines. The 
recent publication of several investigations on the influence of 
parasites on the anatomy of their host-plants greatly facilitated 
the compilation of the general part of the work. 

I have here attempted to summarize in a systematic manner 
the preventive and combative agencies available against the 
more important diseases of economic plants. In many cases 
these are supported by facts given in the chapters on the 
natural and artificial infection of host-plants, and their disposition 
towards diseases produced by lower organisms. 

As already indicated in the title-page, the book deals only 
with those diseases of plants produced by the cryptogams and 
other lower organisms of the vegetable kingdom. The large 
number of parasites which attack such lower plants as algae 
and lichens, although not altogether neglected, have as a rule 
been omitted, otherwise the book could not have been brought 
within the limits of a single volume. In the second or systematic 
part of the book, the pathological phenomena are considered 
along with the description of the organism producing them. 
"Where the diseases are of economic importance, measures for pre- 
vention and extermination are also suggested. Notices of greater 
length are given to such parasites and diseases as have formed 
the subject of special investigations. We could only aim at a 
complete list for Germany and the neighbouring countries, yet 
we have included many species of interest occurring in other 
parts of the world, notably in America. 

Though it will be possible to identify most of the more 
important parasites by the aid of this book, we do not intend 
it to replace the systematic works ; we purpose rather to add 
to the descriptions given in Ilabenhorst, Saccardo, and similar 
works. This book is intended above all to be, in the terms 
of its title-page, "an Introduction"; hence it seeks to orient 
in a general way, to give a summary of our knowledge, and to 
indicate the way to more detailed records. On this account 
great care has been taken in the citation of home and foreign 
literature, not only up to the time of finishing the manuscript 



AUTHOR'S PREFACE. VU 

(Easter, 1894), but also during the time of proof-reading up 
till the following Christmas. 

Keference to the book will be rendered easier by the numerous 
illustrations, wliich are almost exclusively the work of the autlior, 
and reproduced either from drawings or from photographs of the 
living objects, in many cases taken in situ, I consider it more 
essential to illustrate the habitus of pathological objects rather 
than to give drawings of microscopic subjects ; those one may 
find in other works. Some of the illustrations are copied from 
the excellent plates of Tulasne, Woronin, De Bary, Klebs, Ileess, 
Cohn, and Robert Hartig ; while a number of woodcuts have 
been borrowed from the well-known Lcliiiiucli dir Baurnl-rank- 
heitcn of the last named autlior. 

The grouping of the ' Fungi imperfecti,' which have not yet 
been worked up for the German flora, is based on Saccardo's 
Sylloijr ; lience the arrangement into Hyalosporae, etc., which 
is intended for the benefit of those having access to Saccardo. 
Particular attention has l)een paid in the two Indices to the 
scientific names of both parasites and hosts, to popular names, 
and to technical expressions. 

In my labours I received great assistance from the following 
sources : From the collection of pathological material begun by 
Professor Robert Hartig, and now carried on with my helj* in 
the Botanical Institute of the Pioyal Bavarian School of Forestry 
in Munich ; from the facilities for research and photography 
afforded by the laboratories of the same institution ; from the 
Royal Library of Municli, the Library of the University, and the 
private pathological library of Professor Hartig. 

Living material for investigation has been kindlv sent to me 
from many sources, particularly from the following gentlemen : 
Herr Lehrer Schnabl of Munich, (Jeh. 01)err(!gierungsrath Trof. 
Klihn of Halle, Hofgiirtner Kaiser of Munidi, Prof. Dr. Fries 
of Upsala, Forstrath von PliinTiies and 01)erf6rster Loscli at 
Amorbach. Preserved material came from Herr Hauptlchrer 
Allescher of Municli, Director Dr. Goethe and Dr. Wortmann in 
(^leisenlieim, Pmf Dr. Stahl of -lena. Prof. Dr. Magnus of Bi'riiii, 
Prof. Dr. Grasmann and Prof. Dr. Loew of Tokio. Dr. I '.runs 
of Erlangen kindly photographed some specimens in I lie botanical 
museum there. Numerous botanists have greatly assisteil me by 
sending papers, especially Dr. Dietel of Leipzig; I have .dso (o 



vm AUTHORS PREFACE. 

thank him for valuable aid with the Uredineae. To Prof. Dr. 
Soxhlet I am indebted for literature and the opportunity given 
to estalilish a museum of pathological material in connection with 
the agricultural division of the Munich Technical School. Dr. 
Solla of Trieste, while working in our laboratory here, very 
kindly translated the earlier fascicles of the ' Funghi parasitici ' 
of liriosi and Cavara as far as they were then published. Prof 
I »r. Wdlliiy allowed me to carry out some researches on his 
experimental fields. Very opportune were the investigations of 
my pupils, Dr. Woernle and Dr. W. G. Smith, on the anatomical 
changes in plants attacked by Gyranosporangeae and Exoasceae 
respectively. 

To all these gentlemen, and to many more who sent me 
material, but whom it is impossible to name individually in 
this place, I here express my warmest thanks. 

The reproduction of my drawings and photographs has been 

most carefully carried out by Herr 0. Cons^e of Munich. I am 

also deeply indebted to the publisher, Herr Springer, for the 

excellent manner in which he has done his work ; this will 

no doubt be also appreciated by the reader. 

V. TUBEUF. 
Munich, December, 1894. 



NOTE TO THE ENGLISH EDITION. 

Since the publication of this work, I have received a large 
contribution of original papers. Though there was no time to 
embody all these in the English edition, yet many of them 
have been used for its correction and amplification. Some were 
of such a kind as to necessitate the re-writing of whole sections, 
notably those on the genera Exoascvs and Gymnosporangium. 
The remainder will be thoroughly revised if a second German 
edition be called for. I again take the opportunity of thanking 
all those who have sent me literature, and I shall be grateful 
if they will continue to do so in the future. 

V. TUBEUF. 
Munich, December, 1895. 



PREFACE TO THE ENGLISH EDITION. 

My justification for placinLi; another translation in our libraries 
is that no such book as this exists in the English language, 
and that I could not, for some considerable time, see my way 
to collect so many observations on the cryptogamic parasites of 
higher plants, or to find so many suitable subjects for the 
pictorial illustration of their habits and structure, as Dr. von 
Tubeuf has given us. The work was undertaken all the more 
willingly, because, while working under the guidance of the 
author, I had seen the book take shape in his hands, and even 
added some items to its pages. 

The aims of the book are sutlieiuntly set furth in the aulliurs 
preface, and in the preparation of an English edition these 
have been kept in view. The first or general part and the 
more important descriptions in the second part are practically 
translations, but a certain amount of modification was found 
necessary in adapting the work to the requirements of English 
readers. With this object many additions were made both 
by the author and my.self. Those which 1 have inserted are 
in most cases indicated by the use of (Edit.); this has, how- 
ever, been entirely omitted in the group ' Fungi imperfecti,' 
and nearly so in the Uredineae, on account of the nund)er of 
changes found necessary. I also thought it advisable to indicate 
whether the difl'erent species of fungi liad been recorded for 
Britain and North America; this has been done generally by 
the use of brackets, — (Britain and U.S. America.) The records 
for Britain are taken from the works of I'lowriglit, ]\Iassee, and 
otliers ; those of three groups, — the rrcdineae, Basidiomycetes, 
and ' 1^'iingi imp(!rfecti ' were, howcNn-, icxiscd by I'lofcs-sor J. 
W. II. Trail of Abcirdecn, a \vcll-kiii>\\ii aiithoiil \'. fOr .Vincrifa 



X PREFACE TO THE ENGLISH EDITION. 

the records of economic interest are selected chiefly from Farlow 
and Seymour's Host-Index, which contains the complete list. 

I here take the opportunity of expressing ray thanks to 
Professor I. Bayley Balfour for valuable aid and advice ; to 
Professor J. W. H. Trail for kindly revising important parts of 
the proofs; to my brother, Eobert Smith, for assistance in proof- 
reading, and to other friends who have aided nie. 

The difficulties of translation are well known ; in the present 
case they have been increased by the technical nature of the 
subject, and by the modification which the original has under- 
gone. Faults there must be ; for those I ask the indulgence of 
the reader. 

W. G. SMITH. 

Royal Botanic Garden, 

Edinburgh, October, 1896. 



4j> 



BIBLIOGRAPHY. 



The following are some of the more important general works and text 
books. Books and papers on special subjects are given throughout the 
text as foot-notes : — 

General Works on Fungi. 

TcTLASNE. Selecta fungoruni carpologia. 1861-1865. 

De Bary. Comparative Morphology and Biology of the Fungi, Mycetozoa, 

and Bacteria. English edition. 1887. 
ZoPF. "DiePilze." Schenk's Hamlbuch der Botaiiik. 1890, 
LuDwiG. Lehrbuch der niederer Krvptogamen. 1892. 
Brefeld. Untersuchungen aus dem Gesammtgebiete der Mycologie. 

1872-1891. 
Tavel. Vergleichende Morphologic der Pilze. 1892. 
Saccardo. Sylloge fungoruni. 1882-1893. 
Winter, Fisciieu, and Hehm. '' Die Pilze." Eabenhorst's Kryptogamen- 

flora. 
ScHROETER. " Die Pilze." Cohn's Kryptogameuflora von Schlesien. 1885- 

1894. (Incomplete.) 
ScHROETER. "Die Schleimpilze und die Pilze." Engler-Prantl natlirlichea 

Pflanzenfamilien. 1892-1894. (Not yet complete.) 
CooKE. Handbook of British Fungi. 1871. 
Plowright. British Ustilagineae and Uredineae. 1889. 
Farlow and Seymour. Host-Index of the Fungi of the United States. 

1888-1891. 
Massek. British Fungus-Flora. 1892-1895. 



Works on Di.skases of Plants. 

Unger. Die Exanthi-nic dci' Ptliuizen und «'iiiiL,'t' niit dicscii vtrwandte 

Krankheite)! der (Jewiichsc. \K]:^. 
WiEGMANN. Die Kranklieiten und krankiiaftun Mif-liildungiii dr: ( Icwii.lise. 

1839. 
Meyen. Pflanzcnpathologie. 1841. 



xii BIBLIOGRAPHY. 

De Bary. Untersuchungeii liber die Brandpilze und die durch sie verur- 

sachten Krankheiten der Pflanzen. 1853. 
KiJnx. Die Krankheiten der Kulturgewiichse und ihre Verliutiing. 1858. 
H.XLLiKK. Phytopathologie ; die Krankheiten der Kulturgewsichse. 1868. 
H.\UTi(i, R. AVichtige Krankheiten der Waldbiumie. 1874. 
Haktio, R. Die Zersetzungser.scheinungen des Holzes. 1878. 
Frank. Die Krankheiten der Pflanzen. I. Aufl. 1880, II. Aufl. 1894-1896. 
Hartig, R. Lehrbuch der Baumkrankheiten. I. Aufl. 1882, II. Aufl. 1889. 

(Editions in English, French, and Russian.) 
Smith, Worth. G. Diseases of Field and Garden Crops. 1884. 
Soraukr. Haudbuch der Pflanzenkrankheiten. II. Aufl. 1886. 
Wolf and Zopf. Krankheiten der landwirthschaftlichen Nutzpflanzen 

durch Schmarotzerpflanzen. 1887. 
Sorauer. Die SchJiden der einheimischen Kulturpflauzen durch thierische 

und pflanzliche Schmarotzer. 1888. 
Marshall Ward. Timber and some of its Diseases. 1889. 
KiRCUNER. Die Krankheiten und Beschadigungen unserer landwirthschaft- 
lichen Kulturpflauzen. 1890. 
Frank and Sorauer. Pflanzeuschutz. 1892. 
Prilliecx. Maladies des plantes agricoles et des arbres fruitiers et forestiei's 

causees par des parasites vegetaux. 1895. 
Zeitschrift fiir Pflanzenkrankheiten (since 1891). 
The Publications of the Division of Vegetable Pathology of the Department 

of Agriculttire, U.S. America, issued from Washington. 
The Bulletins of the Agricultural Experimental Stations, issued by many of 

the States and Universities of the United States. 
Exsiccata of Parasitic Fungi, by {a) Briosi and Cavara, {b) Eriksson. 
" Economic Fungi " of U.S. America, by Seymour and Earle ; Exsiccata 

begun 1890, (still being issued). 

Etc., etc. 



^ 



CONTENTS, 



FART FIRST. 

CHAPTER I. 
THE PARASITIC FUNGI. 

PAGE 

§ 1. DEFixiTioy OF THE Parasitism of Fcxgi, - - - 2 

§ 2. Classification of Parasites and Saprophytes, - - 3 

v5 3. Mode of Life of the Parasitic Fungi, - . . 7 

CHAPTER II. 

REACTION OF HOST TO PARASITIC ATTACK. 

^5 4. Effect of Parasitic Fungi on their Host, - - - 14 

§ 5. Effect of Parasitic Fungi on the Form of the Host-Plant, 22 

§ 6. Effect of Parasitic Fungi on Cell-Contents, - - 3^ 

§ 7. Effect of Parasitic Fungi on the Cell-Wall, 

§ 8. Effect of Parasitic Fungi on the Tissues of the' 

.')r)6 

580 
CHAPTER in. 

RELATION OF I'AIIASri'K To SCBSTr^^ 

si 0. KiKKCT OK THE SlIISTKATlM ON THE l)KVKLi'' 

I'aka.sitk, 



PAGE 



xiv CONTENTS. 

CHAPTER IV. 
§ 10. NATURAL AND ARTIFICIAL INFECTION, - - 50 

CHAPTER V. 
§ 11. DISPOSITION OF PLANTS TO DISEASE, - - 58 



CHAPTER VL 

§ 12. PREVENTIVE AND COMBATIVE MEASURES, - - 63 

I. Extermination and Rkmoval of the Parasitic 

Fungi alone, ----- 65 

II. Removal and Destruction of Diseased Plants, - 71 

III. Avoidance or Removal of Conditions which Favour 

Infection, ------ 75 

IV. Selection of Hardy Varieties, - - - 81 



CHAPTER VII. 
§ 13. ECONOMIC IMPORTANCE OF DISEASES OF PLANTS, 83 

CHAPTER VIII. 
SYMBIOSIS: MUTUALISM, 86 

CHAPTER IX. 

NUTRICISM, 92 

Hic Mycorhiza, ----- 93 

ic Mycorhiza, - - - - - 97 

-ODOM 

V of the Alder, etc., - - - - 99 

rcoDOMA'i 

of the Leguminosae, - - . . 101 



CONTENTS. XV 



PAltT SECOND. 

SYSTEMATIC ARRANGEMENT OF THE CRYPTOGAMir 
PARASITES. 

PAOB 

I. THE PATHOGENIC FUNGI OF PLANTS, - - - 104 

A. Lower Fuxgi (Phycomycetes), - - - - 106 

(1) Chytridiaceae, - . . . . log 

(2) Zygomycetes, - - - - - - 114 

(3) OoMYCETES : Peroxosporeae, - - - - 115 

B. Higher Fungi (Mycomycetes), - - - - 135 

ASCOMYCETES, - - - - - - 136 

A. Gymxoasci, - - - - - 137 

The Parasitic Exoasceae, - - - 144 

B. Carpoasci, ..---. 168 

Perisporiaceae, - - . . 170 

Pyrexomycetes, - - - - 183 

Htsteriaceae, ----- 232 

DiSCOMYCETES, ----- 240 

Ustilagineae, --.--. 275 

Uredineae,- - - - - - - 328 

Basidiomycetes, ------ 421 

Fuxgi Imperfecti — I. Sphaeropsideae, - - - 463 

II. Melanconieae, - - - 482 

III. Hyphomycetes, - - - 496 

II. THE PATHOGENIC SLIME-FUNGI, - - - 522 

III. THE PATHOGENIC BACTERIA, - - - - 530 

IV. THE PATHOGENIC ALGAE, - - . . r,39 



INDEX OF PARASITES, ------ 556 

GENERAL INDEX, - - 580 



EERATA. 



Page 



9, 


Fig. 1, for " 


35, 


line 11 from 


181, 


„ 24, for ' 


185, 


,, 6, /o)-' 


195, 


„ 3, for ' 


256, 


„ a, for' 


305, 


,, 11 from 


312, 


,, 16, for 


337, 


r 
„ 10, /or' 


355, 


„ 25, for ' 


403, 


,, 9, for ' 


404, 


„ 5, for " 


420, 


„ 3, for ' 



Erysipheae " read " Erysiphe." 

foot, for " tyrosin " read " trypsin," 

' quercinium " read " quercimim." 

' Nectrina " read " Nectria." 

' setuloso " read " setulosa." 

'Belionella " read " Beloniella." 

foot, /or Tolysporium" read "Tolyposporium." 

" heloscladii " and " Heloscladium " respectively, 

ead " helosciadii " and " Helosciadium." 

' Onybrychis " read " Onobrjchis." 

' Cichoria " read " Cichorium." 

' Cypressus " read " Cupressus." 

' Escheveria " read " Echeveria." 

' Thecospora " read " Thecopsora." 



PART FIRST. 

CHAPTER I. 

THE PARASITIC FUNGI. 

The true Fungi, together with the Myxomycetes or Slime-fungi, 
and the Schizomycetes or Bacteria, constitute a group of the 
Cryptogams characterized by lack of chlorophyll. In consequence, 
the members of the group are unable to utilize light as a source 
of energy, and must obtain their food as organized material, 
complex in comparison with the simple substances required by 
green plants. These fungi, in short, are, in common with animals, 
ultimately dependent for the greater portion of their support 
on living or dead chlorophyllous plants. According as they 
obtain nutriment from dead organic remains ui- finiii living 
plants or animals, we distinguish them as Saprophytes and 
Parasites respectively. The same mode of niuiition is found 
in the case of most non-chlorophyllous IMianerogams, and also 
in a few chlorophyllous plants, both Cryptogams and Phanero- 
gams. 

When parasitic Fungi, P)acteria, and other lower organisms 
attack liigher plants, they, as a rule, endeavour to penetiate the 
living organs of their host. It is only when this penetration 
has taken place to some extent, and the parasite has thereby 
come into more or less close contact with the tissues of its host, 
that conditions suitable to a parasitic mode of nutrition are 
established. 

To deal with the lower forms of vegetable parasites, witli their 
relations to their respective hosts, and with the structural altera- 
tions whifli tliey Ijring into existence in tlie latter, is our oltject 
in the present book. 

A 



2 THE PARASITIC FUNGI. 

§ 1. 1>KFIMTI()N UF THE PARASITISM OF FUNGI. 

Parasitic Fungi are those which, stimulated by the cell- 
conlents of another living plant, penetrate wholly or partially 
into its tisstu's, and draw their nutriment from that source. 

Saprophytic Fungi are those which make no attempt to 
pent'lratr the ti.ssiies of living plants, but derive their nutriment 
from a dead substratum. 

Intermediate between these two extremes come those fungi 
which, in con.sequence of some stimulus, attempt to effect an 
entrance into the tissues of living plants by the secretion of some 
Huid or ferment, but only attain their object after first killing the 
part they attack {e.g. Sderotinia sderotiorum). A special position' 
mu.st also be ascribed to certain forms which inhabit the wood 
of trees, but have not the power to penetrate through the outer 
tissues ; they depend on first gaining entrance through wounds 
into dead parts of the bark or wood, and, after living there for 
a time as saprophytes, extend into the living elements and cause 
their death. 

Many parasites may be artificially cultivated so as to pass 
some part of their life-history on dead pabulum, and even in 
natural conditions many of them regularly live for a season in 
a saprophytic manner. On this account it appears to me more 
correct, in distinguishing between parasites and saprophytes, to 
lay less weight on the adaptation to nutrition and more on their 
response to the stimuli exerted by living plant-cells. The nature 
of this stimulus which affects parasitic hyphae has not as yet 
been investigated. It appears probable, however, especially from 
the investigations of Pfeffer and Miyoshi,^ that the influence is 
primarily a chemical one, and that the nutritive value of the 
stimulating substance is not a measure of the ensuing effect. 
Biisgen states that the formation of adhesive-discs by germinating 
spores is induced by a stimulus due to contact, whereas the 
production and penetration of the first haustorium is independent 
of contact, and is probably due to some chemical stimulus (see 
p. 9). Miyoshi's investigations have also proved that saprophytic 
fungi are capable of penetrating into living plant-organs, even 

' Miy oslii. ' ' Ueber Chemotropismus d. Pilze. " Bofcw. Zeitung, 1894 ; also ' ' Die 
Durchbohruiig von Membranen durch Pilzfaden." Pringsheim' fi Jahrhuch, 1895 

Pfeffer. "Ueber Election organisclier Nahrstoffe." Pring-slieim's Jahrhuch, 
1895* 



DEFINITION OF THE PARASITISM OF FUNGI. 3 

of boring through cell-walls, if the part be impregnated with a 
stimulating solution. They behave here completely as parasites. 
For example, hyphae of PenicUlium glaucum penetrate into living 
cells of a leaf injected with a two per cent, solution of cane 
sugar, while without previous injection of the leaf they have 
never been observed to do so. PeniciUium is also known, in 
certain circumstances, to become parasitic. 

Many species of fungi are capable of passing the whole or a 
part of their life as parasites on living plants. Conspicuous in 
this respect are the Uredineae and Ustilagineae, many Ascomy- 
cetes, including all Exoasceae and Erysipheae ; and amongst the 
lower fungi, most of the Chytridiaceae and all the Peronosporeae. 
Xor does this exhaust the list, for amongst the remaiuintr fungi 
we may find isolated families, genera, and even species occurring 
as parasites, while forms closely related to them are saprophytic. 

To classify the parasites, saprophytes, and intermediate forms, 
we shall adopt that arrangement proposed by Van Tieghem and 
De TJary. 

§ 2. CLASSIFICATION OF PARASITES AND SAPROPHYTES. 

1. True saprophytes are such as regularly pass through their 
whole life-history in a saprophytic manner. They may derive 
their nourishment from ditlerent kinds of pabulum, or be limited 
to some definite substratum. The true saprophytes do not come 
witliiii tlif scope i,f this book.^ 

1*. Hemi-saprophytes (the 'facultative parasites' of De Bary) 
are wont to pass through their whole development as saprophytes, 
but on occasion are capable of existing wholly or partially as 
parasites. Amongst tiiem are included particularly such species 
as may be designated " occasional parasites," which commonly 
occur as saprophytes, and only under certain conditions become 
parasitic. 

o. True parasites (i lie 'obligate parasites' nf I )c I'.aiy). These 
undergo no part of their development as saprophytes, but live in 
every stage of existence as parasites. 

4. Hemi-parasites (the 'facultative saiiro])hyics' di Dc liaiy) 
are cai)able, if need be, of becoming sa|)roj)liytcs tor a season 

' .loliow propoHes tliu term Holo-siipropliytes for tliusf imii cl)l(>ni|iliylli)ii.s 
I'h.iiit,-rf)giiiii8 whicli live exclusively «iipr<ii)liytic on orf^iinif deliii.s, in lontiawt 
to those possessing cliloropliyll, wiiiili lie nanits llemi saprophyte«. 



4 THE PARASITIC FUNGI. 

but as a rule they live throughout their whole development as 
parasites. 

Within each of these four divisions one may introduce a 
number uf sultdivisions. 

Hemi-saprophytes. 

The majority of saprophytes are never parasitic, yet there are 
a number which become so occasionally. Thus some species of 
Mucor and PemciUium can penetrate into thin-skinned fruits, and 
this they do the more easily, the further the fruits are from the 
condition of full ^•ital energy, to use De Bary's expression.^ 
Ivelated to these are other fungi which, although incapable of 
efl'ecting entrance into plants in active life, may yet do so as 
the plant, though still living, begins to wither. In such cases 
the parasitism is somewhat difficult to prove. In particular, the 
so-called ' Fungi imperfect! ' contain forms of this kind. 

Amongst the hemi-saprophytes we may include the species 
of Botrytis, which are able to penetrate into unfolding parts of 
plants, but not into the older parts. We may specially mention 
Botrytis Douglasii as a form more generally known as a sapro- 
phyte, but which becomes parasitic on immature organs, and 
which penetrates young needles of various conifers to kill them, 
whereas it is unable to attack older needles. In this case the 
thickness of the membranes would seem to act as a protection, 
just as the vital energy of the plant does in the preceding cases. 
In Sclerotinia sclerotiorum, Scl. ciborioides, and Scl. Fucheliana, 
a saprophytic existence must, as in the example just mentioned, 
precede the parasitic condition ; in fact De Bary holds that 
these forms can only become parasites after their mycelium has 
been saprophytically strengthened ; the parasitic condition is not 
necessary to them, for they can go through their whole develop- 
ment on a dead substratum. Pythium De Baryanum is also to 
be regarded as a hemi-saprophyte which attacks and kills 
seedlings of many plants as a parasite, but otherwise vegetates 
on dead plant remains. Cladosporium herharum, one of the 
commonest of saprophytes, behaves similarly, but it is of less 
frequent occurrence than Pythium, and in fact its parasitism has 
only been suspected quite recently. 

'This has been confirmed by Davaine (Compt. rend. LXiii., 1866, pp. 277 and 
344) and Brefeld {Sitzunffsber. d. natur/orsck. Fr. zu Berlin, 1875). 



CLASSIFICATION OF PARASITES AND SAPROPHYTES. 5 

As further examples of funj_;i, capable, as parasitts, of killing; 
living cells, but which pass through more or less of their life 
as saprophytes, may be taken species whose mycelium inhaljits 
the wood of trees and shrubs. Amongst these are numerous* 
Pohjporeac, which find admission only by wounds in the wood. 
At first these destroy and derive nourishment from the substance 
of dead parts of the wood, but later they begin to attack the 
parenchyma of the living wood, and extending outwards kill, 
as they go, cambium, bast, and rind, till they reach the exterior, 
and there develop sporophores. As examples we may take 
those species investigated by W. Hartig of Munich, (uj. Pohj- 
j)orus fomentarius, P. igniarius, P. Hartigii, P. -sulphtircus, 
Stercum Mrsutum, Tramdcs 2^ini} 

The heart-wood is a part of the tree generally avoided by 
insects, which would in very short time destroy the sap-wood 
with its rich starch-content, e.g. Annohiac in oak. Again, the 
heart-wood resists the iufiuence of certain saprophytic fungi 
much lunger than the sap-wood, hence it is preferred as the 
timber used for railway sleepers. Although in these cases we 
might describe the heart-wood as possessing antiseptic properties, 
yet this would scarcely be accurate, since it is just this very 
heart-wood which is always first attacked by the wound-parasites 
of trees, and gives them a hold on the tree as parasites. See 
also Chap. V. 

Since these dangerous tree-fungi can live wholly as sapro- 
phytes in the heart-wood, and in the sap-wood partly as such, 
partly as parasites, they are also able to vegetate further, and 
to reproduce themselves on felled stems, especially when the 
necessary moisture is provided. Thus, for example, Agaricus 
adiposi's, a wound-parasite of the silver fir, produces its yellow 
sporophores on felled stems and split wood during the whole 
summer in moist parts of the forest, while in a ceUar or other 
moist chamljer the development of sporophores may continue over 
a year. In fact, I have found that a billet of beech- wood, after 
being placed under a glass and allowed to lie completely dry, 
on again being soaked from time to lime, continued to ])roduce 
a crop of toadstools annually for five years. 

Some wound-jiarasites occur occasionally as typical sapro- 
phytes on dead wood. Thus J*ofi/j)oni.-< (iitno.'iiiti, perhaps bultrr 

' R. Hurtig, ZirHftzuiiijuerxcliiiiiitii;/! II il^ ■< Ilol-.rx, ISTH, mnl othir wmks. 



G THE PARASITIC FUNGI. 

known as Tmmctcs radicipcrda, is an undoubted parasite of 
pines, spruces, and other trees, yet on timber in mines ^ it 
grows luxuriantly, and reproduces abundantly from sporophores, 
wliieli, however, differ somewliat from the typical form. Again, 
the rhizomorph-strands of Agnricvs mclhus grow under dead 
bark, in thf earth, in mines, and in wooden water-pipes, while 
other forms of its mycelium are completely parasitic ; thus 
the apices of the rhizomorphs penetrate the bark of young 
conifers, and, in the form of a mycelium, live parasitic on rind, 
bast, and cambium. 

FoIi/jwTKS Tcrporarivs, a true parasite on living Scots pine, 
is also an enemy of timber in newly-built structures, or in 
subterranean spaces and cellars, so long as it can obtain the 
necessary moisture. Polyporus sidphureus produces sporophores 
on the bark of living trees, as well as on the dead stools of 
felled trees. Many other related forms would probably be able 
to live on dead timber if they were not dependent on a certain 
degree of moisture, and could submit to drying-up as easily as, 
for example, Fohiporiia alietinus, a true saprophyte, and one of 
the most conmion enemies of old wooden bridges. 

Fungi from other groups are also known to effect an entrance 
into the wood of trees through wounds only, yet when once in, 
they spread rapidly, and at length bring about the death of their 
host. The spores of Cucurhitaria laburni were demonstrated 
by me to germinate on the laburnum, on wounds produced 
by hail and otherwise, and to send into the wood so exposed 
a mycelium, which spread through the vessels and into the rind, 
killing all the tissues on its way. Similarly Ncctria cinnaharina, 
after it has killed its host, lives thereon as a saprophyte, and 
develops patches of conidia and perithecia on the dead bark. 
Peziza Willkommii, although really a strict parasite on the living 
rind, yet continues to grow and to reproduce itself on the dead 
branches. 

Hemi-parasites. 

If the examples already given, i.e. Mucor, Penicillium, Botrytis, 
Pythium, are typical of hemi-saprophytes, then there may arise 
a doubt whether the remainder, the wood-destroying Polyporeae, 
Ncctria, Cucurhitaria, and Agaricus mdlcus, should not be regarded 

1 Harz, Botan. Centralblalt, 1888, Vol. xxxvi. ; Magnus, Botan. Verein d. Prov. 
BraiKlf'uhiir;/, 1888. 



CLASSlFICATIuX OF PARASITES AND SAPKUl'HYTES. t 

as hemi-parasites. They must, however, be inchided amongst 
the hemi-saprophytes, because doubtless they are capable of 
going through their whole development as saprophytes. The 
hemi-parasites include, amongst others, the Ustilagineae, all of 
which live for a time as parasites, and cannot, even by artificial 
cultivation, be made to complete their life-history as saprophytes. 
"While, however, many of the Ustilagineae are adapted to a com- 
pletely parasitic life, others can, in the form of sprouting conidia, 
live and multiply saprophytically. The conidia of Exobasidinm 
and Enjascus continue to bud oft" conidia for a considerable time 
in nutritive solutions, yet in nature, the spores proljably produce 
infecting hyphae at once, and the fungus is but little suited to 
sustain a saprophytic mode of life. Phijtuphtltord infcsfans is 
more easily reared as a saprophyte, and occurs in nature as such, 
hence it approaches somewhat towards the hemi-saprophytes. 

True Parasites. 

The Uredineae may be taken as the most typical of the true 
parasites : they constantly pass through their whole life-history 
on living plants, and cannot be cultivated on a dead substratum. 
So also the Erysipheae, although frequently their spores only 
reach maturity on a dead substratum, as do also those of 
Rhytisma and Fubjstujma. Enjot of grain and the Sclcrotinia 
inhabiting berries, are also truly parasitic, even though their 
apothecia or perithecia are produced from hibernating scU-rotia. 
and though their conidia can be saprophytically cultivated on 
dead paltulum. 

The Peronosporeae and I'rotomyces are also true parasites. 
In many other forms the development of germ-tubes, or the 
sprouting of conidia, may be obtained in artificial nutritive 
solutions by exclusion of rival fungi and liacteria, yet it i.s 
doubtful whether this takes place in nature. 



§ 3. MODK i)V \AVV: OK IIIK I'A lIASl'I'IC l-TNiJl. 

The parasitic t'ungi may be di\i(leil aecordiuL; to the place of 
their occurrence and their nioile of attack on the host, into two 
categories, which may lie designated eiiiphytic and eudojihytic 



8 THE PARASITIC FUNGI. 

parasites. ^ The former have their vegetative mycelium spread 
over the surface of the host-plant, the latter penetrate into the 
plant and there develop their mycelium. Doth receive nourish- 
ment from the cells of the host-plants, generally by means of 
special absorptive organs inserted into the cells of the host, the 
so-called haustoria. 

"We may distinguish the following groups of parasites accord- 
ing to the degree of their penetration into the organs of the 
host-plant they attack : 

1. Epiphytes: {a) with haustoria which only sink into the 
outer membranes of the host ; 

{h) with haustoria penetrating into the cavity of the host- 
cells. 

2. Endophytes : {a) with a mycelium which grows in the 
walls of the host-cell, and is generally nourished without tlie aid 
of haustoria ; 

(h) with a mycelium which grows in the intercellular spaces 
only, and is nourished with or without haustoria ; 

{c) with a mycelium which penetrates into the host-cells and 
becomes an intracellular mycelium ; 

{(]) lower fungi which live completely in a host-cell. 

1. Acquisition of nutriment by the epiphytic parasitic 
fungi. The simplest mode of acquiring nutriment is found in 
yeasts (Saccharomyces apicvlatus, etc.) which frequent the outside 
of living fruits, and live on the drops of sugary solution which 
diffuse therefrom."^ 

' Epiphytic parasites always produce their reproductive organs outside their 
host-plant. Ill the case of endophytic parasites, the reproductive organs of 
some are produced inside the host-tissue, e.f/. the zygospores and oospores of 
Chyfridiaceae and Peronosporeac, the chlamydospores of the Ustilcuiineae ; others 
form their sporocarps wliolly or partially embedded, the spores and conidia only 
heing discharged externally ; while a large number form sporocarps on the surface 
after the epidermis has been torn. Conidia are generally abjointed from the 
free surface of the host-plant. 

Tlie terms epiphytic and endophytic parasites have been chosen with regard to 
the development of the parasitic food-al)sorbiiig mycelium. Some authors I'egard 
epiphyti.sm somewhat differently, and include amongst endophytes those forms 
which live on the surface of the host and penetrate only by haustoria. If this be 
accepterl, epiphytism is very exceptional amongst parasites of the higher plants. 
Zopf (" Die Pilze") gives as examples of this condition only the following: the 
Lahoulhtniareae inhabiting the chitinous skeleton of certain insects, and j\IeJano- 
xpora paraxitira on filaments of species of Ixaria ; these have no communication 
between the mycelium and their host. Species of CAae^oc/ofZ^tm parasitic on fungi 
and absorl>ing the cell-wall of the host at the point of contact, could, strictly 
speaking, no longer be classed as epiphytes. 

-Btisgen. " Ueber einige Eigenschaften d. Keimlinge parasitiseher Pilze." 
Botrm. ZfiiuiKj, 189.3. 



MODE OF LIFE OF THE I'ARASITIC FUNGI. 



I can however liardly rej^ard as parasites, fungi like these 
which live on an accidental outflow from plants or plant-cells, 
even though they regularly i'requent places where an outflow is 
to be expected. They exert no influence on the host-plant, 
and they are nourished by substances which can no longer be 
regarded as belonging to the host. I would rather include 
them amongst non-parasitic epiphytes which, without specially 
adapting themselves, settle on any part of a living plant where 
sugary solutions suitable for their nutriment may occur. ' One 
might imagine however such epiphytes inducing a dittusion of 
nutritive sul)Stance from the cells of the host-epidermis to the 
closely adherent fungal hyphae ; then we should have the 
simplest mode of parasitic acquisition of nutriment on the part 
of epiphytes. They would take up food-material from the epi- 
dermal cells in much the same manner as many intercellular 
hyphae do from the adjoining walls of the host-cell.^ 

Epiphytic parasites frequenting the surface of plant-organs 
generally endeavour to increase their supply of nutriment from 
the host-cells by formation of haustoria, which pierce the cuticle 
or the whole cell-wall. Blisgen has shown experimentally 
that the adhesive discs, often formed on the germination of a 
spore, owe tlieir origin to a contact-stimulus ; the formation and 
direction of the infecting hyphae, on the other hand, thougli 
depending on this, are ujudi more determined by a stinjulus 
originating from the host-cell itself. In tliis wo have a confirma- 
tion of the accuracy of our definition of 
parasite and saprophyte. 

The appressoria, adhesion-organs or 
adhesive discs just mentioned, are char- 
acteristic of many parasites. They are 
formed chiefly on epiphytic mycelia, 
but also accompany tlie earlier life of 
other fungi. In the case of epiphytes, 
pores are furmed on definite ])laces of 
such an adhesive-disc, and from these 




Fid. 1.— * 



-»j>, SlHiru of Eri/fijihtat- 

umlxdi/iraritiii goriiiiiiatiiig on tho 

, . Ill II- eiiidorniiK cif u lioHt-iilaiit ; an lul- 

haustoria are develoiied, or a nypha is hcHi..i,-.iiMiHii.ih.iu»toriuiiiLuvobct!ii 

„, , "^ , , ■, ^ formeil. (.\ftir Dc liaiv.) 

given otl and enters tlie host-plant to 

form a mycelium. Tlic appressoria *>{' thi* Miysiphi-ac arc Nt-ry 

characteristic; in many tliey are bniad lobctl discs (Fig. 1); in 

' ('i>iii|)aie tliose ciiHUH of ]iiiriiHite.s on iiin»-ot« ainl fiin^'i iiliiMily ^jivfii, p. S (nntf). 



10 



THE rAKASITlC FL^NGI. 



Others, like Podospharra castagnci, they take the form of broadened 
closely-clinging hyphae with haustoria. Frank describes a swell- 
ing of the germ-tube of Fusicladium tremidae just before the 
infecting hypha pierces the cell- walls of its host. A similar 
phenomenon can be observed in Polystigma rubrum, in Gnomonia 
erythrostovui, and in the germinating aecidiospores of Mclampsora 
Gocppevtiana. Some other examples will be mentioned in our 
next section. 

Haustoria of the epiphytic Parasites. 

The most inconspicuous haustoria are those of Herpotrichia 
nigra and TricJio-ydirteria vnrasitica, described by E. Hartig.^ 




Flo. 2.— Haustoria of Trickosnhaeria parasitica. (Details on Fifr. 88.) 
(After R. Hartig.) 



They are tiny hyphal processes resting on the host-epidermis, 
and sunk into the outer walls of the epidermal cells, so as to 
pierce the cuticle but not the whole wall (Fig. 2, d, e; also 
Fig. 90). The Erysipheae are typical epiphytes, which weave 
a mycelium over the surface of plants they attack ; the 
mycelium retains its hold by adhesion -discs or appressoria, and 
from certain parts of these a fine thread-like process is given 
off, which, after piercing the epidermal wall of the host, swells 
inside to a simple or branched sac, the haustorium. The 

^Lehrburh if. lianmh-anlcheiten, II. Aufl. English translation by Professor 
iSonierville. Mucniillan & Co., 1894. 



MODE OF LIFE OF THE PARASITIC FUNGI. 11 

haustoria of Fodosjjharm castagmi (Fig. 7 1 ) are bladder-like, 
those of Oidiuvi Tnckcn are lobed. 

The simplest* formation of haustoria consists in an outgrowth 
of the mycelium which depresses the cell-wall of the host 
without piercing it (e.g. Pcronospora densa). In other cases the 
cell-wall, at first only depressed, becomes ultimately broken 
through. 

Certain lower fungi live parasitic on other fungi and adhere 
to their hyphae by means of well-developed adhesion-discs from 
which haustorial structures are formed inside the hyphae of the 
host. Thus Piptociyhdis frcsenia is parasitic on hyphae of some 
species of Mncor, and produces from a swollen bulb-like appres- 
sorium a tuft of very fine haustoria inside the il/«c;o?'-hypha. 
Syncephalis proceeds even further, for the haustorial process grows 
and branches inside the host, becoming, in fact, an endophytic 
mycelium. A further advance towards endophytic parasitism 
is presented by the Chytridiaceae, low forms of fungi living 
on algae or fungi ; some send haustorial structures into their 
host, others develop a niyceliuiu whose attack however is 
directed against only one host-cell. Fischer, in his " Fhycomy- 
cetes," thus describes the latter forms : " The vegetative body, 
a resting swarmspore, consists of a spherical or ellipsoidal part 
which becomes a sporangium, and of a filamentous vegetative 
portion which spreads through the host-cell as a haustorium or 
mycelium and dies away after the formation of the spoiangiuiii. 
This primitive mycelium is unicellular, and may be unbranched 
or very finely branched." 

2. Acquisition of nutriment by the endophytic parasitic 

fungi. Til'' siniijlest rase of the eiidnph} lir iiHulr nl' IiIl- is 
presented by those fungi which vegetate in the epidermal 
membranes of their hosts, and derive tiieir nutriment osniotically 
througli the inner cell-walls. They live covered by tiie cuticle, 
which must have been penetrated by an infecting hypha at the 
time of first attack. This mode of life is exhibited l)y many 
fungi, particularly by the E-nxtscmc ; the mycelium of these 
vegetates under the cuticle of the host ])lant, and nipiures it at 
the time of ascus-formation. In spite of their limited distri- 
l)Ution the species of this group so inlluence the development 
of their hosts as to induce pustule-like (nitgiKW ths, iTunijiJing 
and distortion of leaves, and evt-n "witi'hes' brooms." in seme 



12 THE PARASITIC FUNGI. 

of the Ecoasccac the bases of the asci penetrate deeply between 
tlie walls of the epidermal cells, so forming an intermediate 
stage leading to other Uxoasccac and endophytic fungi, with a 
mycelium growing between, or in the cells of tissues which lie 
deeper than the epidermis. 

The mycelium of Cydoconium oleaginum grows in the epi- 
dermal cell-membranes, branching dichotomously under the 
cuticle and sending through it erect hyphal branches for pro- 
duction of conidia.^ The germinating conidia of Sjjhaceloma 
amjjelinum are said by De Bary to penetrate the cuticle, and 
to produce a mycelium which spreads thereunder and breaks 
out just before formation of conidia. Myeoidca parasitica, an 
alga, lives under the cuticle of leaves of Thea and Camellia. 

We have next to consider fungi with a mycelium which 
lives and multiplies in the intercellular spaces of living plants. 
Like the E.coasceae just mentioned, they push their way between 
neighbouring cells and spread through the already existing 
intercellular spaces. Numerous Uredineae behave in this way, 
and towards the period of reproduction the mycelium is capable 
of increasing so much that the cells of the host-tissues become 
isolated and even displaced. The various species of Hystcrium 
have an intercellular mycelium, which kills those cells with 
which it comes in contact. Certain forms, e.g. Caeoma 2yinitor- 
quum and Feridermium ^jmi (Fig. 247) possess a mycelium 
which, while still intercellular, sends off here and there little 
lateral branches into the host-cells. It is an easy step from 
forms like these to forms whose mycelium is no longer strictly 
intercellular, but derives nutriment by means of specialised 
haustoria. 

Haustoria of the endophytic Parasites. 

A large number of endophytic parasites frequenting hosts which 
do not immediately succumb to their attack, possess "haustoria" 
or special organs for the acquisition of nutriment from the 
cells of tlie host. The haustoria are lateral outgrowths of the 
mycelium with a limited period of growth and a more or less 
constant form. Tliey are more varied in form, but otherwise 
quite comparable with haustoria of the epiphytes, especially 
witli those of the Erysipheae. One of the simplest forms of 

' Figures in Fuwjhi Parasitti, Cavara and Briosi. 



MODE OF LIFE OF THE PARASITIC FUXGI. 13 

haustoriuia on an endophytic mycelium is that exhibited by 
the parasite Cystoinis ; the hyphae send oft' very tine filaments 
which penetrate the walls of a host-cell and swell up to little 
Ijutton-like sacs. Many Peronosporeae {P. i^yfjrafua, P. niira, 
P. viticola and Phi/tojyhthora omnivora) have haustoria of the 
form just described, whereas others have them thread-like and 
branched {P. calothcca of the woodrutf), or crenately lobed {P. 
parasitica). 

Amongst the species of Uredineae and Ustilagineae, haustoria 
are not uncommon and present many varied forms. They are, 
however, few in numl)er, or confined to certain parts of the 
mycelium, so that they may be easily overlooked. 

Haustoria in the form of long sacs of various lengths are 
produced by Melampsora Goepijcrtiana in the tissues of both 
cowberry and fir-needle. Gi/mnosporaiKjium in juniper has 
occasionally very delicate button-like haustoria. En(hip]njUum 
sempervivi in the house-leek has haustorial bianclie.s which, 
according to Zopf, are coiled together and anastomose frequently 
with each other. Tuhurcinia amongst the Ustilagineae possesses 
.short branched haustoria resembling one-sided clusters, and 
Mdayiotaenium endogenum has similar haustorial-tufts even more 
branched.^ Urocystis piomijliohjgodis in Hipatiea trihilm has spirally 
coiled haustorial hyphae, while Tilhtia cndopliylla, Sorosporiuiii 
sajjonanac,- and many species of LhtUayo, have haustoria with 
the form of knotted hyphae. 

Amongst the Hymenomycetes, Ejxibnsidiiim vaccinii forms 
a mycelium which permeates the host-tissues with numerous 
hyphae, but the only haustoria are hyphae which here and 
there penetrate into a cell. Xo haustoria have as yet 
been found amongst the IJasidiomycetes,^ Pyrenomycetes, or 
Discomycetes. The two groups last-mentioned have an inter- 
cellular or intracellular mycelium, which as a rule ([uickly 
kills all cells with wiiich it comes in contact. 

\SencLeiibf.rr/i.ich'' ualnrforscli. 6V.s. AlihamU. 1S80. Plates I. ami I\'. 

- Priii'/xhehn's Jahrhuch, 18G9. Plates VII., VIII. 

^Saiaiiw luw figured haustoria in iiiycorhizji of beech, without however 
iletermiiiiiig exactly whether they heloiigeil to a Hymenoinycete. Reesa also 
figures similar organs on iiiycorhiza jnoduceil Ky one of the Tuheraeeue. 



CHAPTER II. 
REACTION OF HOST TO PARASITIC ATTACK. 

The reaction of the host to the attacks of parasitic fungi is 
fairly constant for the same host and fungus. The various 
fun<Ti, however, exert on the same host-plant each an influence 
of its own, while different host-plants behave very differently 
under attacks of the same fungus. 

§ 4. EFFECT OF PAEASITIC FUNGI ON THEIR HOST.i 

A. Killing of Host-Cells.^ 

1. Absorption of living cell-content by parasitic fungi. 

Tlie lower fungi give us examples of the simplest mode in 
which fungus-parasites draw nutriment from their host-cells ; 
particularly those forms parasitic on algae or other fungi. 
The most primitive of all are numerous species which, applying 
themselves to a host-cell, bore through its walls and enter 
the cavity. There they derive nutriment at the cost of the 
living cell-content, — the plasma, cell-sap, chloroplasts, starch 
grains, etc., — and finally kill the cell. The host-cell does 
not survive the later development and reproduction of the 
parasite. The effect of the fungus is however limited to the 

' Billroth ("liber die Einwirkungen lebender Pflanzeii und Thierzellen aufeiiian- 
i\cr, " Sammlunfi Medic. Schriftc.n. Wiener Min. Wncheiiblatt, 1890), compares in a 
masterly way the effects of micro-organisms and of injuries on animal and vege- 
table tissues. He employs Virchow's terms " formative stimulus " and " formative 
irritaljility " ; the former to denote the capacity of micro-organisms in producing 
outgrowths of definite form or the formation of new tissues ; the latter, the 
capacity of the tissues to react to such stimuli, and to produce outgrowths, 
etc. A comparison of the external phenomena of fungoid diseases in the case 
of animals and plants recently formed the subject of a short paper by Lewin. 

- Perniciasmus. 



EFFECT OF PARASITIC FUNGI <>N THEIR HOST. 15 

cell attacked which is at once killed before it can enlarge ur. 
otherwise react to the influence of the intruder. * Good examples 
of such parasites are presented by some of the Chytridiaceae 
— the Arcliimycdcs of Fischer — which, as a rule, inhabit only 
isolated cells of their respective host-plants. This mode of 
nutrition is equivalent to that of the Myxomycetes and Mycetozoa, 
which absorb the cell-contents after completely enveloping the 
living cell, or after slipping insiile or sending a haustorial process 
into it. 

A second series of parasites consists of those wliich live 
on the contents of the host-cell, and give it time to react to 
the stimulus exerted by the intruder. The reaction generally 
results in a cell-enlargement or fungus-gall, which in the simpler 
cases includes one cell only. Tlie gall harbours one or more 
parasites, which gradually use up the cell-contents. As examples 
we have Olpidium tumaefacicns and 0. undinU} Pseudolpidium 
saprolegniae, Olpidiopsis saprolegniae, Rhizomyxa liypogaea'^ etc. 
A specially striking case is that of PIcotrachdvs fulgens, which 
causes the rudiment of the sporangiophore of Pi/oholus Klrinii 
to become hypertrophied and gall-like.^ 

We have as a third series those parasites which penetrate 
into living cells and absorb their contents, at the same time 
stimulating the host-cell to abnormal and increased growth, as 
well as some surrounding cells not directly in contact with the 
funt'us. In this case the parasite exerts a far-reaching eH'ect, 
and produces a gall composed of more than one cell. Species of 
Syncliyt rill III are exaniples. The fungus itself penetrates into one 
cell only, which enlarges ; but simultaneously the surrounding 
cells grow and multiply to form a wall or rampart enclosing the 
cell originally attacked. Other parasites do not absorb the' 
host-contents as a whole, but only withdraw osmotic substances 
by means of delicate processes of the fungus-hyi)liae. These 
haustoria penetrate the wall of the host-cell, but the fungal 
protophism inside them remains separated from the liost-jtroto- 
plasni by a delicate membrane. In the case of the viiu'-mildcw 
and some other Erysii)heae, the cells thus preyed on turn brown 
and die. With other related forms {e.g. Sphmrntlurn radagnci), 

' See Fischers I'hyrnmyctlts. 

-"I'liiH c-iiUHfs a slight swelling of the loot-hiiirs r>f vaiiciiis jdiints uiiil iilisorbs 
their content. 

^Zopf, /S> ilriKjf -.ur I'hysliil. ii. Muifiluil. iii'il. Onjaiiistin ii, II. lS!l"J. 



16 REACTION OF HOST TO PARASITIC ATTACK. 

absorption by haustoria results in a deformation and distortion 
of attacked organs, which embraces even cells far distant from 
the point of attack, yet without death following directly to 
any cell. 

2. Absorption of cells or tissues by parasitic fungi. Tiie 
total absorptiiiii of cells or tissues by parasitic fungi constitutes 
a special form of cell-destruction. Cases of this kind occur 
particularly amongst the Ustilagineae. Thus Urocystis violac so 
stimulates the cells of Viola that they divide and produce a 
delicate tissue, rich in protoplasm ; this nutritive tissue is used 
up when spores are formed, but without any great detriment to 
the host-plant. At the time of spore-formation of other Ustila- 
gineae a great destruction of the host-tissues may, however, 
take place ; this is especially marked in attacks of Ustilacjo 
nuo/tUs, U. avcnae, Tillctia tritici, on the ovaries of their 
respective hosts, as well as in other cases to be considered 
later. 

.'!. Killing of host-cells and tissues by fungi which excrete 
ferments. The simplest case under this heading is presented 
by species of Sclerotinia studied by De Bary, e.g. Sd. sclerotiorum. 
The mycelium of these, while still lying on the outer surface of 
the host-plant, excretes a ferment which sinks through the mem- 
branes into the cell-cavities, causing death to the protoplasm and 
even destruction of whole tissues. 

A similar process may be assumed in the case of numerous 
fungi with a mycelium which grows only in the intercellular 
spaces, yet causes immediate death to any cell it may touch. 
This is the case with many leaf-spot diseases, like those due to 
CercoqwiYi, Hysterium, etc. So also do the apices of rhizomorph- 
strands kill portions of the bast of living Conifers with which 
they may come in contact. The rapid death of tissue following 
the attack of such deadly fungi as Phyto-phthora is probably 
due not altogether to the deprivation of nutriment, but also to 
the effects of a poisonous excretion. This, however, has not as 
yet been satisfactorily ascertained. 

B. Killing of Organs or Whole Plants. 

A large nundjer of fungi have a mycelium which never ex- 
tends beyond a very short distance round the point of first 
infection, and causes only local disease, frequently with no 



EFFECT OF PARASITIC FUNGI ON THEIR HOST. 17 

perceptible disturbing effect on the host. Such is the case 
particularly with leaf-spot diseases ; the tissues of isolated spots 
are killed and fall out, the leaf appearing as if perforated by 
shot, but otherwise exhibiting no discoloration or other symptom 
of disease. In contrast to these there are fungi which, directly 
or indirectly, bring altout death of their host or some part of it. 

The simplest example of parasitic fungi killing their host 
directly is presented by one-celled or few-celled plants, which 
soon succumb to attack even on a single cell. Where, however, 
the host is a highly organized plant, its organs will resist the 
attack of the parasite for some time. Thus with Pliytoplithoro 
fagi, the mycelium spreads rapidly through the tissues of a 
seedling, so that death ensues in a few days. Similarly species 
of Peronospora rapidly kill leaves, branches, and fruits ; likewise 
Cladosporium , Stptoria j^fasitica, and others. 

Somewhat different in their action are those fungi which 
kill some tender part of a plant directly, and thereby in- 
directly further the death of other parts dependent thereon.. 
As examples, take Pcstalozzia Hariigii (Fig. 301) and Phoma 
abietina (Fig. 293), which kill only some small portion of a 
young plant or branch, but thereby cause drying-up of higher 
or distal parts. Gihhrra rarcinii on stems of cowberry (Fig. 95) 
is another example. Similarly cankers arising from Ncdria 
ditissima (Fig. 80), or Pcziza Willkominii. Again, Agaricus 
mclleus and Tramctcs radiripcrda kill roots or lower portions of 
the stem, and bring about the death of trees of all ages. 

The case varies somewhat witli ceitain wound-parasites like 
Ncdria einnaharina and Cucnrhitaria Inhu.rni. There the my- 
celium extends so vigorously in the water-conducting organs, 
as to kill them and till up the vessels, causing thereby so 
serious a disturbance in conduction, that branches or whole 
plants wither away in summer. The wood-destroying Pol gpo rear 
and Agaricini act similarly, allluiugli nmre slowly; they attack 
large branches and stems, destroying all ])arts of the wood, 
duramen as well as sap-wood, and finally the bark. 

There are also cases where organs of the attacked host 
remain alive, but sulfer on account of tlie hy})ertr(tphy of other 
parts. In tliis way portions of a plant may be killed altliouyh 
not directly the seat «»f the parasite. This is jiartieularly the 
case wheie hypertr<(})hied organs undergn iiirieased gmwlh and 

r. 



18 REACTION OF HOST TO PARASITIC ATTACK. 

Utilize the water which would otherwise have ascended to 
higher parts of the branch-system (Fig. 3). It must indeed 
be assumed that the latter are preyed on by the hypertrophied 
parts and give up plastic material, which they would otherwise 
have utilized themselves or stored up as reserve material. 
On branches attacked by mistletoe and other phanerogamous 
parasities, it can easily be observed, particularly on broad- 
leaved trees, that a supporting branch grows vigorously in the 
parts under the influence of the root-system of the parasite, 
whereas the distal parts of the same branch-system remain 
stunted and finally die. The mistletoe-bush thus comes to form 
the termination of the supporting branch. If, in consequence 
of this, the branch ceases to produce the leaves necessary in 
preparing food for it, then like every other leafless branch it 
dies. Such branches carrying leaves of the mistletoe alone may 
frequently be found on firs, pines, and broad-leaved trees ; 
even whole tree-summits have been seen on the silver fir with 
every branch terminated by a mistletoe-tuft, not unlike some 
huge candelabrum. 

In a similar manner a witches' broom, developed from a 
lateral bud, exhibits throughout an increased growth, while the 
branch supporting it remains thin and dies from the insertion 
of the broom outwards. So also in attacks of G-ymnosporangium 
on juniper it may be observed that the parts attacked have 
their growth much accelerated and many of their dormant buds 
developed, while the distal parts of the same branch die off. 
In all such cases it is quite probable that, as the distal parts 
die back, any food material which they may contain finds its 
way into the hypertrophied region. 

C. Shortening of Life. 

Many fungi inhabit a plant without disturbing the develop- 
ment of any part or causing immediate death, yet with such 
effect that the vegetative period of the organ in question 
terminates earlier than normally. 

A very striking example of this is presented by the needles 
of silver fir on the witches' brooms caused by Aecidium 
elatimim. The needles normally vegetate for several years, 
but when influenced by this parasite they live only a single 
.season. So also needles of spruce attacked by Aecidium cor- 



EFFECT OF PARASITIC FUNGI OX THEIR HOST. 



19 




li i. :;. tijuii.iciit rcitAi. Witchos' broom of tliuriy. Tliu HiiiiportiuK' tiniiich in 
lifud from itM iipcx biifkwurdM to the Hvut of miiiifictoil liitor.il tiuU, wliich luin 
(lovulofHjd Into 11 witchcM' broom. On the trt-c tlie BiipiKirtinK' bniiich iMiintcd 
slitfhtly moro downwards thim iH slicwn. i niitunil h1/u. (v. Tulwuf jiliot.) 



20 KEACTION OF HO.ST TO PARASITIC ATTACK. 

i(sca7is, which may, in addition, bring about death of the whole 
shoot. Needles of spruce beset by aecidia of Chrysomyxa 
rhododmih'i are cast after reproduction of the fungus in August 
or September, while with Chrysomyxa ahidis the needles of 
Conifers fall in May. The latter examples differ somewhat 
from the former in that the mycelium lives in the w^itches' 
broom for years, and continues to send out new shoots with 
deformed needles, whereas in the Chrysomyxa attack the my- 
celium is confined to the needles and falls with them. 

Examples from other groups of fungi are the witches' brooms 
of Alnus incana caused by Exoascus einjjhyUus. The leaves of 
these are fully developed though somewhat modified in form ; 
their life-period is, however, shorter than that of normal leaves, 
and they fall earlier. It may be observed here that this 
phenomenon • of premature defoliation is one recorded as a 
consequent of many parasites. The witches' broom twigs of 
the alder grow and produce buds almost normally, yet the 
whole broom-system dies in a few years, and long before the 
normal life-period of the tree. 

The war of extermination by mycelium against host-plant 
may frequently last for a very long time. Hartig gives an 
example of a larch which had carried on the combat with the 
larch-canker (Peziza Willkommii) for over eighty years, Ijecause 
during active vegetation of the host the parasite was unable to 
make headway. 

D. Premature Development of Buds. 

The unfolding of buds in spring in advance of those of 
normal plants is also a feature of many diseased plants. This 
is manifest in the earlier unfolding of buds on witches' brooms 
of the silver fir and cherry. The alder witches' broom, already 
referred to, is however exceptional, in that its buds open after 
those of normal twigs.^ 

A premature fiowering may also result, so that flower-buds 
formed in summer unfold the same autumn instead of during the 
following spring. Thus in a recent autumn a violet opened 
in a plot in the garden of Trofessor Hartig in Munich. The 
flower was found to be somewhat stunted, and its stalk beset 

' Smith, " Untersuchungen d. Anat. u. Morph. der durch Exoasceen veru- 
sacliten def oniiationen. " Inaug. Diss. Munich, 1894, p. 16. 



EFFECT OF PAKASITIC FUNGI ON THEIR HOST. 21 

by pustules of Urocystis violac, the mycelium of which had 
perennated in the stem. Kerner in his " Pflanzeii-lelten " ^ 
mentions a similar case where flowers of Primula clusiaiw. and 
P. minima attacked by Uromyccs ^^riM «/«<.' intcgrifoJiaf unfolded 
prematurely in autumn. 

E. Preservation of the Host-Plant and of Host-Tissl'es. 

(('ONSERVATIOX.) 

In contrast to those parasites which attack a plant, or parts of 
it, and immediately kill it or otherwise exert a direct destructive 
influence, we have these which live for a longer or shorter period 
with their host without producing such an effect. Cohabitation 
of this kind may last only for a short time and terminate with 
the first reproductive period of the fungus, or it may last for 
years as a perennating syml)iosis, or as a perpetual one like that 
of lichens. 

This phenomenon is particularly conspicuous amongst the 
Uredineae. These throughout their whole development adapt 
themselves to an existence with living host-cells, so that the 
latter die only after the reproduction of the fungus. Frequently 
the mycelium lives in perennial organs for a length of time, 
even for many years. The attacked parts are of course injured 
to a certain extent, and hypertrophy of the most varied kind, 
accompanied by characteristic phenomena, may take place, yet 
this only towards the termination of the period of development. 

The Ustilagineae are in a similar manner adapted to an exis- 
tence in living organs, and there produce their spores. At the 
time of spore-formation and liberation they are deadly enemies of 
their host-tissues, yet previous to this they vegetate in the 
living tissues with little or no apparent injurious eti'ect. Some 
like Udilfff/o j>r/rnn"iis, even pass the winter in the living ln^st- 
ti.ssue without killing it. 

The individual species of the Hysteriaceae, Discomycetes, 
I'yrenomyeetes, Hymenomycetes, and lower fungi differ very 
much in their action; many of them iidiulnt living tissues for a 
length of time without injurious effect, while not a few. like the 
Exoasceae, even perennate from year to year. The galls j)ro- 
duced as a result of EinJidsidii/m do not die till thf fungus lias 
reproduced itself. It is unneci-ssary at this place to ^ivc details 

' Kiiglisli I'Mitioii, yatiira/ //it/<,ri/ o/ I'ldiits (OVwi-v), ii., p. .V_'.'). 



22 



REACTION OF HOST TO PARASITIC ATTACK. 



of Other examples, since many of these will be referred to again 
in other chapters, particularly when hypertrophy is under consi- 
deration. 

§ 5. EFFECT OF PARASITIC FUNGI ON THE FORM OF 
THE HOST-PLANT. 

1 . Arrest of growth, and Atrophy. While a large number 
of fungi produce more or less extensive enlargement of parts 
of their host, others cause arrest of organs, crippling, impoverished 

nutrition, and even atrophy of 
an extreme kind. Incompletely 
developed organs of this kind 
may originate even where the 
fungus in possession produces 
only local hypertrophy. In- 
teresting examples are presented 
by many species of Synchytrium 
{e.g. S. taraxacum and ^S*. ane- 
onones). The former is endo- 
phytic in Taraxacum, and exerts 
a stimulus resulting in increased 
growth, not limited to the 
single cell attacked, but ex- 
tending to neighbouring cells, 
which, in consequence, multiply 
and form a ring-like swelling 
round it. The leaves as a 
whole, however, are poorly developed, so that the lamina in 
very extreme cases may be represented only by the midrib and 
narrow margin (Fig. 4) ; while on leaves attacked on one side, 
that side alone is stunted, the other is normal. Taraxacum 
leaves badly attacked by Fuccinia are not at all deformed, 
whereas those of Anemone show striking arrest of growth (Fig. 
190). Leaves of Cirsium attacked by Fuccinia suavcolcns exhibit 
an arrest of the same kind, remaining less divided and of 
softer texture (Fig. 186). 

Flowers affected by parasitic fungi present many striking 
malformations. Magnus ^ describes such a case in Anemone 

' Magnus, " Einfluss v. Parasiten auf d. Ausbildung d. befalleneu Pflanzen- 
theiles. Naturrciss. Buiulschan, 1891, No. 25. 




Fig. i.—Synchytrhi.m taraxaei. Partial atrophy 
of laminae of Taraxacum officinale. About j 
natural size. (v. Tubeuf phot.) 



EFFECT OF PARASITIC FUNGI ON THE Fol!M OF HOST-PLANT. 23 

I. 

raminculoides under the intiuenee of Atcidivm j^'^'nctatvin. .In 
the simpler cases the floral leaves were narrow, elongated, and 
greenish, stamens were formed but not carpels ; in more pro- 
nounced cases, the petals were only represented as snmll, simple, 




Kk;. 5. — Clieirv true iu Ijlossniii, witli throe " witch 
(v. Tubouf phot.) 



IjlLolM-- ' in f.'li:lj,'L 



stalked, green leaves, the stamens were reduced in nund)er and 
there were no carpels. One case exhibited, in place of a fldwer, 
only two leaflets terminating the flower-peduncle, imic of them 
})ahuiit('ly divided. 



■24 



REACTION OF HOST TO PARASITIC ATTACK. 



True atropliy is best seen in those cases where ilower-forma- 
tion is suppressed. This effect of parasitic fungi on their host is 
by' no means uncommon, the fungus alone reproducing itself, 
while the assimilating host-plant remains sterile. This atrophy 
is found not only in annual plants, but also in those where the 
symbiosis might be designated as perennial. The last-mentioned 
case is exemplified in Accidium clatinum, the witches' broom of 
which never bears flowers ; again, by witches' brooms of Exoascus 




^i?' ^.— £'(i/)/to)-/>ja Ci/parisslas. A healthy lowering normal plant compared 
with the attenuated non-flowering form inhabited by Aecidiuni eunhorbiae. 
(V. Tubeuf phot.) 

ccrasi (Fig. 5), which bears only leaves when the rest of the 
tree, is in blossom. Another perennial symbiosis behaving thus 
is shown in Euphorhia Cyparksias attacked by Aecidium 
eiiphorhiae; year after year the diseased shoots produce only 
leaves, which assist in the reproduction of the fungus (Fig. 6). 
Similarly with many other Uredineae. 

Arrest of the seed occurs in ovaries of species of Pnums under 
the influence of Exoasci (Fig. 7). In flowers attacked by Ct/stopm 



EFFECT <»F PARASITIC FUN<;i ON THE FORM OF HOST-PLANT. 




the ovules become atrophied, whereas the rest of the flower 
is hypertrophied. Similarly witli 
flowers of cowberry deformed Ity 
ExohamUvm. 

2. Hypertrophy. — ^lany para- 
sitic fungi cause abnormal enlarge- 
ment or other malformation of 
plants which they attack. The 
simplest case of hypertrophy is 
seen in the enlargement of a uni- 
cellular plant as a result of an 
endophytic parasite, e.g. Pilobolus 
Kleinii with Flcofrachdus. 

The same example is also tlu- 
simplest possible case of a gall 
caused by a plant, and distin- 
guished by the name of " fungus- 
galls " or Mycocecidia, from Zooce- 
cidia, the galls caused by animals. 
Larger galls occur on leaves 
attacked by Synchytrinm, where 
not only the single cell attacked 

becomes enlarged, but also the surinunding cells; these galls, 
however, form but tiny points on diseased leaves. Similar 
small and local enlargements of the leaf-cells, accompanied 
frequently by cell multiplication, are caused by many other 
fungi, c.(j. species of Exoasciis. More extensive malformation may 
embrace some part or even the whole leaf, so that it is more 
or less enlarged and beset with l»lister-like outgrowths, as with 
other Exoasceae (see Figs. 62 and 64). Other gall-forms are 
presented by Eivhafiiilivm on the alpine-rose (Fig. 250), where 
the gall is always hjcalized t<j a small area of the leaf, and 
<jn the cowberry, where the gall may extend over whole leaves, 
and even include! the shoot (Fig. 256). 

Hypertrophy of the whole shoot, resulting in elongaiion and 
thickening of the twigs, is a i»henomenon fretjuently met with 
in the " witches' liromns," to be referreil to later. And just 
as entire branch-systems may become hypertropliifd and elon- 
gated, so may whole plants, if tlie myccliuin, insti-ad »»r rciiiainiuL; 
localized, spreatls throULjImul the jilant. Ivvaiupli's ^>'( tlii-~ will 



Fig. ".—Fruit of plum deformed by 
Exoascus pi-uni ; the stone is shrivelled 
and abortive. 4 natural size. (v. Tubeuf 
phot.) 



26 REACTION OF HOST TO PARASITIC ATTACK. 

be described when we consider Euphorbia with Accidium 
eiqyhorhiae (Fig. 6), house-leek with Endophyllum, anemone with 
Accidium (Fig. 190), and cowberry with CahjiJtosjpora (Fig. 202). 
Where plants, like the cowberry and anemone, live in com- 
munities, then these elongated individuals rise above their 
healthy neighbours, and the fructifying fungus has a better 
chance of having its spores distributed by wind. It must, 
however, be observed that when hypertrophy of a whole shoot 
or plant occurs, every part need not be enlarged to a propor- 
tionate extent ; in fact some parts generally remain abnormally 
small, e.g. leaves in cases of rusts upon cow-berry, fir, anemone, 
and others. On the other hand, both shoots and leaves may 
be abnormally enlarged, as in cases of alder with Exoascus 
Tosqninctii or Ex. epiphyllus.^ 

Hypertrophy of the roots occurs on alder, where large tubers 
are produced by Frankia (Fig. 21). On Leguminosae, tubercles 
of various sizes are caused by Rhizobium (Fig. 22). Eoots 
of Juncus develop thick-lobed outgrowths as a result of Schinzia 
(Fig. 179). Eoots of turnip infested by Flasmodiojjhora have 
irregular swellings of all sizes (Fig. 315). Mycorhiza frequently 
exhibit tubercles or balls formed by the massing together of 
very short dichotomously branched rootlets into clumps (Fig. 18). 
Cycad-roots, under the influence of Rhizobium and Nostoc, also 
exhibit hypertrophy.^ 

We shall now proceed to consider hypertrophy of the repro- 
ductive organs, and at the same time to notice some other 
changes induced in the flower by parasitic fungi. 

Influence of parasitic fungi on the development of reproductive organs 

of host-plant. 

Disease of the flower and fruit, when not caused by fungi 
which kill the cell, generally causes striking floral malformation. 
These we may group as follows : 

1. Atrophy or total suppression of flowers. 

2. Arrested development of flowers. 

3. Development of rudimentary organs. 

4. Abnormal formation of flowers. 

5. Hypertrophy of parts. 

6. Transformation into sclerotia. 

^See also § 7. -Schneider, Botanical Gazette, 1894, p. 25. 



EFFECT OF PARASITIC FUNGI ON THE F<>RM UF HOST-PLANT. 27 

The two first cases have already beeii considered. The arrest 
of the flowers of anemone, as a result of Aecidium jmnctatitm, 
is a further example of Case 2, and at the same time exemplifies 
Case 4, in that the floral leaves become green foliage leaves, 
though of a very stunted kind. The petals of Cruciferae hyper- 
trophied under the influence of Ci/stn])i's candidus often l»ecome 
green, and at the same time much altered in shape, 

A particularly interesting case is presented by the develop- 
ment of the stamens of the pistillate flowers of Lycltnis dioica 
infested by the mycelium of Vsfil(i(jo rioiacca. These stamens 
normally remain rudimentary, but in the diseased abnormal 
flowers become fully developed like those of the staminate 
flowers, except that the spores of the parasite replace the 
pollen in the anthers. Giard ^ has designated this phenomenon 
as "castration parasitaire," and he distinguishes three modifica- 
tions amongst unisexual flowers. 

(«) Stamens appear in pistillate flowers ("androgene castration 
parasitaire "). This occurs, as already mentioned, in pistillate 
flowers of Lychnis dioica. frequented Ijy UstUiKju. 

(b) Ovaries are developed in staminate flowers (" castration 
thelygen "). Examples : Ccirc- i)^'("-COx with Ustilago ccrricis, 
Buchloe dactyloides with Tilletia. huchlo'eana, and Androjwyon 
provincialis with Ustilago andro230ijonis. 

(c) In flowers of either sex the sexual organs of the other 
appear in consequence of the influence of the parasite ("amphigene 
castration parasitaire "). Giard compares these cases with that 
of the development of the organs of the latent sex in animals, 
e.g. of cock's feathers on an old hen, or growth of hoins f»n 
castrated or " gimmer " animals. In both cases the phenomenon 
is due to the same cause; in the animals the organs of the 
latent sex appear as the result of the normal organs becoming 
functionless or being destroyed by castration ; in the plants 
through stimulation of the latent rudiments by tlie fungus, 
which does not, however, cause suppression of the organs 
already present. "In some respects the i)henomenon is comparable 
with what happens wlun the terminal shoot of a tree is lost 
and some neighbouring lateral shoot tui-ns vertically upward 
to replace it. 

The effect of fiinui ou tlic rejiroductive organs of plants 

' Miiii^iiii and ( liiuil, /!iil/i/iii srimt. <li la Fritiio it tir la Jii/ijii/in , |SS4. 



28 REACTION OF HOST TO PARASITIC ATTACK. 

may also be seen amongst lower cryptogamic plants, two cases 
of which may be mentioned here.^ Plcotrachelus fulgens, 
inliabiting the mycelium of Piloholus Kleinii, causes the 
formation of galls and the suppression of sporangia, while at 
the same time zygospores, normally rare, occur in large 
numbers. Likewise a species of Si/ncejyhalis parasitic in Filolo/us 
ii-i/st((llini(s causes suppression of sporangia and stimulates 
formation of zygospores. 

The transformation of floral organs may resemble that observed 
by i)e liary, in which, as a result of attack of Peronospora 
violacea on Knautia arvensis, the stamens appeared in the form 
of violet petals. Doubling of flowers is also caused, as in 
Saponaria officinalis, under the influence of Ustilago saponariae, 
and Compositae with Peronospora radii. 

The Ustilagineae, perhaps, cause the greatest amount of varia- 
tion on the flower, because many of them produce their spores 
in the floral organs of their host. Thus, in the anthers live 
Ustilago violacea, holostei, scabiosae, intermedia, succisae, hctonicac, 
major, scorzoncrac, ccqjcnsis, pincjuicolac, Vaillantii, and Tuhurcinia 
primulicola ; the last named also occurs in ovaries and stigma. 
So also do many others inhabit the ovary or some other part. 
Many, like Ustilago rnaydis, form spores throughout the plant 
as well as in the flower, and bring about hypertrophy and 
destruction of parts. Amongst these are Ustilago aveiiac, 
pcrennans, hordei, nuclct, tritici, ijanici ■miliacei, reiliana, cruenta, 
sorghi, Grameri, earicis, tragopogonis, Tilletia lacvis, etc. 

Cystopus (Fig. 35) causes very characteristic hypertrophy 
of all parts of the flower, particularly an enormous outgrowth 
of the ovaries and floral envelopes, whereas other parts are 
arrested in their growth. Wakker investigated a number of 
Cruciferae with flowers deformed by this parasite, and found 
variations in the form and anatomy of the deformations 
produced on the different host-species. 

Ecohasidium also causes well-marked hypertrophy of flowers, 
and even of the whole inflorescence of cowberry, Woronin ^ 
describes and figures such cases (Fig. 256). All parts of 
the flower may be attacked and grow to a great size, becoming 

'Zopf., Beitrage zur Physiol, und Morph. niederer Organismen, 1892. 
Zopf., "zur Kenntniss d. Infections-Krankheiten nied. Thiere u. Pflanzen." 
Xoia Aria d. k. Leop. -Carol. D. Akad. Hallt., 1888, p. 356. 
-Naturforsch. (iesellschaft Freilmrg-i.-B., 1867. 



EFFECT OF PARASITIC FUN<;I UN THE FoEM OF HOST-PLANT. 29 

at the same time tleshy and of a bright rose-red colour ; the 
ovules are sterile or abnormally formed. Wakker, however, 
found no very marked change in the anatomical structure of 
such flowers. 

The species of the Exoasceae also produce striking hypertrophy 
of flowers. Thus there are the sac-like outgrowths of the 
catkin-scales or ovaries of poplar caused by Taphrina Johansonii 
and T. rhizophora (Fig. 52), and the "pocket-plums" or "fools" 
due to Uxoascv.s pruni (Figs. 49 and 51). In these last- 
mentioned cases, the outer layers of the ovary become thick and 
fleshy, sometimes remaining green, while the stone and kernel 
remain rudimentary. The alder, under the influence of Kwascus 
alni incanac, has the catkin-scales nmch enlarged, deprived of 
chlorophyll, and of a red colour (Fig. 53). 

]\Iummification, or the transformation of the fruit into a funsal 
resting-body or sclerotium, is not unfrequent. In some respects 
this process resembles the change in ovaries brought about by 
Ustilagineae. Here, however, we have to do neither with hyper- 
trophy of the fruit, nor yet with its complete destruction. The 
best-known sclerotium is that of Claviays lyvrpurca (Fig. 84). 
It first fills up the base of the ovary, then kills it and grows 
out as a large horn-like sclerotium. The sclerotium of the oak 
{Sderotinia Bafschiana) completely replaces the acorn, leaving 
only the outer covering enclosing it. Likewise, in the mummified 
berries of bilberry, cowberry, crowberry, cranberry, and others, 
one finds the normal parts almost wholly replaced by the 
resting-mycelium of some species of Schrotinia. 

Formation of new Organs. 

Although parasitic fungi commonly induce hypertrophy of 
existent organs and development of normal latent structures, 
they are seldom associated with formation of new organs. As 
such, however, we must regard the formation of adventitious 
buds on the fronds of Pterin quadriaurita, lietz, and Aspiiliuvi 
arisffdinn, Sw., under the influence of Tap/irinn Lamrncia, 
and T. Coimu ccrvi, respectively.^ lUids or bulbils of tins 
kind (jccur normally on several S])ecies of ferns; but in tlmsc 
just mentioned they a])p('ar only as a result of the parasiti', and 
develop into structures icuiindiii^ ouv of a witdu's' broom. 

' (Jieseuliugon, F/orci, IMIl'. 



30 



REACTION OF HOST TO PARASITIC ATTACK. 



Still more striking are certain structures resembling witches' 
brooms, which are produced on Thnj'opsis clolahrata in Japan, under 
the influence of the mycelium of Gacoma deformans (Fig. 8). 
These consist of leafless non-chlorophyllous axes, dichotomously 
branched, and with each branch ending in a disc. They arise 
from shoots or leaves of the Thiijojjsis where structures of the 
kind would never have arisen normally, and are wholly sub- 
servient to the reproduction of the fungus, which forms its 
sori under the epidermis of the terminal discs. 




Fig. 8. ■ Caeoma defornians. The nest-like structures are much-branched, 
leafless shoots with each of their twigs ending in a caeoma-disc. (v. Tubeuf 
phot.) 

The galls produced by Ustilago Treuhii on Polygonum Saccha- 
lincnsc are particularly interesting. Here, as a result of the 
presence of the parasite, there are formed the so-called vegetative 
canker-galls, and in addition, the fruit-galls, new organs derived 
from lateral outgrowths of the host-plant, and of use only 
in the spore-formation of the Ustilago ; they contain a special 
cai)illitium-like tissue, and serve exclusively for the shelter and 
distribution of the fungus-spores. 



EFFECT OF PARASITIC FUNGI ON THE FORM UF HOST-PLANT. 31 

Somewhat doubtful cases are the outgrowths resembling aerial 
roots which arise on Laurus canariensis attacked by Ejxbasidium 
lauri. Geyler, their discoverer, regarded them as deformed stem- 
shoots, but they resemble rather the galls of the alpine-rose. 

§ 6. EFFECT OF PARASITIC FUNGI ON CELL-CONTENTS. 

The most common and, at the same time, most apparent 
effect of parasitic fungi in this direction, is the stimulation to 
cell-division and cell-multiplication. Tliis occurs chietly in 
young tissues, or in those still in process of growth, and gives 
rise to numerous peculiar outgrowths and swellings, some of 
which have already been referred to. 

The parenchyma of mature tissues may also exhibit secondary 
cell-division, when under the influence of a parasitic fungus. 
This I found to be the case in leaf- 
petioles of Umbelliferae attacked by 
Protomyccs viacrosjjorus (Fig. 9). The 
epidermis and vascular bundles are never 
disturbed, but the intervening tissues are 
permeated by an intercellular mycelium, 
which causes the cells to divide into a 
larue number of delicate-walled chambers, ^ „ , „ .. . . 

'^ Fio. 0. — Secondary ccU-division 

all containing nuclei smaller than those in parenchyma of i.etiuic of. -(.f/o- 

'~ jioUiuiii as a result of Protonti/ces 

of neiiihbourinff undivided cells. The macroAponts. The nudei of 'the 

~ ° _ new cells are much smaller than 

same thins is observed in plants of those of the primary ceii. (Cum- 

" _ _ ^ . pare Fig. 47.) (v. Tubeuf del.) 

Viola odorata inhabited by Uroci/stis 

violae ; the mature parenchymatous cells become di\ided up 
by means of delicate walls running in various directions into 
numerous chambers or secondary cells, which Wakker in 
describing has named " nutritive tissue." ^ This nuw ti.ssue 
remains permanently in attacks of Protomyccs, but with Uro- 
ii/stis it is almost completely used up during the formation 
of spores. In some diseases caused by Exoa.sceae, a similar 
secondary cell-division takes place ; for example, in the sub- 
epidermal parencliyma of leaves of jxijilar willi T<ip]iriiu( 
I III. rid (Fig. 6o). 

An interesting (tbservation was made by lloscii-' on ilic direct 

'Wakker, " L'lilei-.siicliuii^'LMi." I'riiKjshi iiit'^t Jd/irlnuli, 18J)2. 

- FioHL-n, /iiitni'ji ;. Ki-iintnisx il. J'//air.i nzi/h . Hal.il. S.lirifl, IS'.H 




32 REACTION OF HOST TO PARASITIC ATTACK. 

effect of haustoria of Uredineae on the cell-uucleus. He describes 
it thus : " The mycelium of Fuccinia asarina permeates between 
the cells of the leaf-tissue of Asarum, and sends into almost 
every cell of the infected part, a short, sometimes branched, 
hyplia, which serves as a haustorium. This grows in almost 
every case towards the nucleus of the host-cell, and becomes 
firmly attached thereto, or completely encloses it. The nucleus, 
in consequence, undergoes considerable deformation, sometimes 
being tightly constricted by the haustorium, or the apex of 
the hypha penetrates deep into the nucleus, pushing the nuclear 
membrane before it." 

Enlargement of the cell-nucleus occvirs, according to Frank, 
in the cells of the root-tubercles of Leguminosae caused by 
bacteria; likewise in the cells of endotrophic mycorhiza of 
orchids. Schlicht,^ in considering the endotrophic mycorhiza of 
Paris qiiadrifolia, says, " One observes here, as in the mycorhiza 
of the Orchideae, that the cell-nucleus, which is very large, can 
exist in the cell beside the fungus-tissue. The hyphae, however, 
frequently penetrate into the cell-nucleus, or surround it in 
a close network." ^ 

The effect of parasitic fungi on the chlorophyll of tissues 
attacked by them is very varied. We may distinguish three 
cases, apart from those in which the parasite kills the host-cell 
and its chlorophyll along with it. In the first, the green parts 
of the plant attacked become bleached by the influence of the 
parasite, and ultimately lose their green colour ; this we might 
designate " mycetogenous chlorosis." Examples are the galls 
of cowberry and species of rhododendron, the results of many 
Uredineae, such as Chrysomyxa rhododcndri on spruce, Accidium 
urticae on nettle, Gymnosporangium clavariaeforme on hawthorn, 
and the leaf-galls due to Exoasceae. 

In the second case, there is a preservation of the chlorophyll 
in places infested by the fungus, in contrast to adjoining normal 

^Schlicht. "Beitragez. Keimtniss d. Verbieitiuig u, Bedeutung d. Mycorhizen." 
Inaug. Diss. 1889, p. 14. 

-Tiroom {" Thiwiia Aseroe and its Mycorhiza," Annals of Botany, June, 
1895, p. .339) describes and figures a similar case. He says, "The fungus 
enters the cell as a single slender hypha, which at once grows directly towards 
the nucleus of the host-cell." He also mentions an observation of Professor 
Marsludl Ward, "that in liemileia of the coffee disease, the haustoria often apply 
themselves to the nuclei of the host's cells. " (Edit.). 



EFFECT OF PARASITIC FUNGI ON CELL-CONTENTS. 33 

parts, which become pale aud die. This is exemplitied in 
Cro'imrtimn asclepiadeum on the leaves of Vincefoxium, Gym- 
nosporonyinm davarinr forme on the quince, Uncinvla accris on 
the Xorway maple, Rhytisma punctatinn on Acer spicatum. 

Intermediate between these two extremes are cases where 
the chlorophyll is retained, but in much reduced quantity. For 
example, organs under the influence of Uxoascus alni incaiuie or 
Aecidiuni clatinum, though still green, are pale in contrast to 
those normally deep green; leaves attacked by Peronosporeae, e.g. 
Corydalis or Anemone with FlasmojJora 2)ygmaea, and Anemone 
with Aeciclium punetatum or Pnccinici fusca ; leaves of Cirhium 
containing mycelium of Puccinia snaveolens ; leaves of alder 
with Eeoascus cpiphyllus, and many 'others. This paler coloura- 
tion of diseased plants is frequently an easy means of recognizing 
them amongst the healthy ones. 

The third case is that of " mycetogenous chloranthy " or the 
development of green colour in organs normally of some other 
colour. Wakker has proved this in the petals and stamens of 
iJrassira nigra and Sisymbrium j^^'^^i^onicum attacked by Cystojws 
and Peronospora. Likewise Magnus showed its existence in 
Howers of Anemone ranunculoides with Aeciclium i^^'-^^'^fctnm. 

The cell-sap, in some cases of hypertrophy, assumes on the 
sunny side a rose colour ; thus in galls caused by Exohasidinm 
on alpine-rose and cowberry, pear-leaves with Poesfelia eanceUota 
and Pnhj>iti(jri\ft ruhrum, catkins of alder attacked by Eroetso's, 
and galls caused by Taphrina carnea on the sweet birch. The 
epidermal galls, due to some species of Synehytriiun {S. rohro- 
ciiictinn, S. anemones, etc.), exhibit an intense carmine coloui. 
Yellow coloration occurs, according to "Wakker, in nettle, buck- 
thorn, and many plants when frequented by Uredineae. There 
may also lie a yellow colour due to the yellow oily contents 
of the mycelium sliining through tlic host-tissues, as in spruce- 
needles with ChrysomyjMi ahietis. 

In considering the ettect of parasitic fungi on the slanli- 
C(jntents of the host-plant, two very distinct cases may be 
observed. There may be, for a time, a greater accumulation 
of starch in the attacked parts tlian in ihi- normal, or the 
parasite may dissolve any starch present and utilize it at I'lii.e. 



34 



REACTION OF HOST TO PARASITKJ ATTACK, 



Aecuiiiulation of starch is described by E. Hartig ^ in spruce- 
needles attacked by Lojyhodermium macrosporum. In the pre- 
sence of the funous-niycelium, an increased production and 
storage of starch takes place at a time when it is being only 
slowly formed in normal iieedles. If the needles become diseased 
during May, a season when they are already full of starch, 
this remains intact in the dead cells till October, when it begins 
to be used up. 

Wakker oljserved accumulation of starch in comfrey with 
Aecidimn asprrifulii, in buckthorn with Accidmm rhamni, in 
hawthorn with Roestelia lacerata, in Sisymbrium ojficincde and 
other plants with Cystopus, in roots of Brassica inhabited by 
PldHmodiophora brassicae, and in hypertrophied scales of alder 
catkins with Exoascus. Many other examples are given through- 
out tlie literature of plant-pathology. 

I'articularly noteworthy is a case of starch preservation in 
oak-wood destroyed by Polyporus dryadeus and P. igniarius 
simultaneously.^ In the wood infested by 
either of the fungi alone the starch is dis- 
solved, but at the boundary where the two 
meet it remains in the medullary rays ; 
these, in consequence, appear snowy white, 
and consist almost exclusively of unchanged 
starch-grains, while the lignified cell-walls 
have been converted into cellulose or com- 
pletely absorbed (Fig. 10). Loew ^ remarks in 
regard to this : " One must assume here a 
variation in the kinds of diastase, and a 
neutralizing effect of the one on the other, 
in somewhat the same manner as pepsin acts 
on tyrosin. One is also reminded of two 
optical antipodes which easily unite into an 

Fro. lU. — Mednllurv vavs i_- ii ; i i i ;> / • \ 

of oak-wood destroyed by Optically ucutral body {e.y. sugar isomers). 







stiiWuir''of undrssoived The dissolutiou of starch by fungi has 
(vi^Tubevtf'phot'T'*'^''^'*'^' ^6en examined in detail by Hartig. 



The 



wood-destroying fungi dissolve the reserve 
starch-grains laid up in the wood-parenchyma in various ways. 
Assuming the view of Naegeli, that starch-grains consist of a 

' Wirhtii/e Kranhheiten d. Waldhiiumen, 1874. 

-R. Hartig, ZtrsetzwKjserscheiniuKjen, 1878. 

■'Loew, 0., Ein naturliches System d. Gift-Wirkungm. Munich, 189.S. 



EFFECT OF rAKASITKJ FLNcil ON CELL-CONTENTS. 



35 




F"io. 11. — Starch grains from tbe oak, in pro- 
cess of dissolution by ferments, «, of Tlitltjilioru 
litidi.i: ; b, of Poti/porus sutj)hu)i:u/i ; c, of Poll/- 
/loiait igniariux. In a and b the iodine-reaction 
is shown by shadinf;. (After R. Hartig.) 



oellulose and a yranulo.se part, Haiti^' describes the proce.ss thus 

(Fig. 11). The iuycelium uf species like F-Ayporu^ v/aiarin.s 

giv^es off some ferment which dissolves the starch-grains, by cor- 
roding them from the outside inwards, so as to form lioles and 

canals similar to those in 

starch-grains in process uf 

dissoluticjn in the cells of a 

sprouting putatu. In others, 

('.(J. Thdephora pcrdii:, the 

granulose is first dissolved 

from witiiout inwards, so that 

finally only tlie starch-cellulose 

remains, occupying a region 

towards tlie outer parts of 

the grain as a kind of husk, 

which is in time gradually 

used up. In Fohiponi^i Hidplttiiru.-i the operation is reversed ; 

the starch-cellulose appears to be dissolved out first, leaving 
a residue of granulose. These observations were based on 

the assumption that the starch-grain consisted of a granu- 
lose portion which turned blue with iodine, and a starch- 
cellulose portion which Ijecame yellow ; or again, on treating 
the starch-grains with dilute acids the granulose was dissolved, 
wiiile the cellulose remained in the form of a skeleton. 
Although more recent investigations have shown that the 
cellulose-skeleton results from the action of the acids, and that 
this view of the constitution of the starch-grain was not quite 
correct, yet Hartig's observations prove that the various fungus- 
ferments have each their own action on starch-grains : his 
results are also supported by otiier facts. 

Other fungi besides Tolyporeae utilize the starch of tlicir 
host-plants, thus J'hijtophtliord in leaves of the i)otato. 

The formation of calcium oxalate is influenced by action of 
parasites. From AVakker's synopsis of tiie phenomena of hyper- 
tiophy, we find that calcium oxalate normally present in iiystal- 
sacs in leaves and fiowers (»f Jilimaiuis Frumjiiln, is wanting in 
parts deformed by ArcuHinn r/i'mnii ; crystal-sacs are less 
abundant in di.seased stems than in healthy : the calcium oxalate 
in galls of J-Jrohasitfin/n is not ]ircs('nt in crystal-sacs, as in the 
non-dt'fornicd organs, l)ut as ili-ilc-tincd solitarv crvslals of limited 



36 REACTION C»F HOST TO PAHASITIC ATTACK. 

number; on the other hand, crystal-sacs, normally absent, are, 
under the influence of Emascus alni incanac, formed in hyper- 
trophied catkiu-scales of alder. 

It inav be liere observed that calcium oxalate crystals are found in tlie 
layceliimi of many fungi. De Bary^ found them very common, particularly 
in the mycelium of species of Botrytis, and he remarks thereon : " it may 
well be assumed that the oxalic acid is formed from the sugar inside the 
living oxygen -absorbhig fungus-cell, but is immediately ejected therefrom 
by the carlxm dioxide j)rodaced in respiration ; in other words, an oxida- 
tion-fermentation takes place in the plasma of the mycelium. The oxalic 
acid is probably separated in combination with potassium and converted 
into calcium oxalate, when calcium is present in the pabulum of the 
iii\ relium."' ., 



^ 7. EFFECT OF PARASITIC FUNGI ON THE CELL-WALL. 

The effect of the mycelial hyphae of parasitic fungi on the 
cell-wall may be either mechanical or chemical. The intra- 
cellular hyphae of fungi and the apices of the haustoria of 
intercellular fungi must penetrate through the cell-walls of their 
host, either of the epidermis, or the membranes of other cells, 
consisting of cellulose alone, or in some state of lignification.- 

The membranes may be simply pricked, as Ijy a fine needle, 
so that the opening, because of the elasticity of the cellulose, 
closes up again after the perforating hypha has died. This 
is the case with many Uredineae. In such cases the hypha is 
constricted in passing through the cell-wall and swells out again 
in the free cell-cavity. Trequently, as in the case of Pcrono- 
spora detisa, the haustorium will only cause a depression in the 
membrane of the cell without penetrating it. 

In addition to purely mechanical perforation of the mem- 
brane, the effect of the hyphae may also be a chemical one, so 
that the wall is dissolved and the holes produced remain long 
after the hyphae which made them have disappeared. This 
solvent effect is probably always present in cases where per- 
foration of lignified membranes takes place. It is a constant 

1 De Bary. Botan. Zeittmi/, 18S6. 

- De Bary. Biology and Morphology of the Fimgi. English Edition. 
H. M. Ward. " On a lily-disease," Annals of Botany, 18SS. 
Miyoshi. " Die Diuxhbohruiig v. Membranen durcli Pilze." '■■Prin<jshe.im' » 
Jahrhnch, Vol. 28, 1895. 



EFFECT OF PARASITIC FUNGI ON THE CELL-WALL. 37 

accompaniment of the attacks of wood-destroying fungi on the 
woody parts of trees and shrubs. Besides actual perforation 
of the lignified membranes of their host, the hyphae of many, 
of the Polyporeae and Agaricini exert a solvent effect on the 
walls, which extends over a considerable area, and is evidently 
due to the excretion of some ferment. The dissolution of the 
walls takes place, moreover, in a way so characteristic for each 
species of fungus that they can be determined by it alone. From 
this it must be deduced that each wood-destroying fungus 
excretes a ferment peculiar to itself, which causes a character- 
istic dissolution of the host. Our present sources of informa-, 
tion on these points are the very valuable investigations of 
Professor Robert Hartig of Munich.^ Some of his results will 
repay our careful consideration, Ijut we must preface briefly 
some facts regarding the process of lignification and the forma- 
tion (jf heart-wood in our forest-trees. 

The elements of the wood of dicotyledonous trees and woody 
plants are derived from the cambium ; their walls consist at 
first of pure cellulose, and when lignification takes place the 
so-called incrusting substances are laid down in the thickened 
cellulose wall, particularly coniferin, vanillin, wood-gum, tannin, 
etc. ; or as they may be collectively called, lignin. The cellulose 
membrane itself is coloured lilac with chlor-zinc-iodine ; when 
lignified it no longer shows this reaction, but has others peculiar 
to itself, the best known being red coloration on treatment 
with phloroglucin and hydrochloric acid, or yellow coloration 
with aniline sulphate : chlor-zinc-iodine colours lignified tissues 
brownish-yellow. Copper-ammonium-hydrate dissolves cellulose 
but not wood.- If the incrusting substances be removed from 
the lignified membranes by treatment with Schulze's solution, 
caustic soda, or other solvent, the cellulose remains and reacts 
as sucIl In the process of conversion of alburnum into dura- 

' Tlie most iiii|)ortaiit of these woi'ks are : 

iJit Zt^rsif.iui'js' r.srhfiiiuiii/i n 'I. Ho/jsil. Xa>lil/iol:.tr n. d. Kirln . With 'JI 
eohjiireil plate.-'. Springer, Berlin, 187S. 

/>r fi-hlt Huuxsi-liiramm, MtriilinK larltryuiniis, 1885. 

Wirhliijt Kraukhtitt n <l. \Val<lh<ium<-, 1874. 

Lthrf/nrfi d. liunmkrnnkh<ili-n, I. and II. K.lition, ISS'J ami IHSH. Kiiirlish 
lran«latioii of II. K<lit. hy Prof. W. SonRiville. 

Lilirhurh d. Aiintomi' u. /'fii/.-iioloijii d. I'jldir.i ii, iSid. 
- For further reactions see : 

Zininiennunn. Dit^ hotaiiiMcht' Mirrotirhnik. IS'Ji. 

Strusburger. IJuh hotaiiisrht J'rnktikiim, 1887. Knglinii Ktlilion, iss'.t. 



38 



REACTION OF HOST TO PARASITIC ATTACK. 



men other substances make their appearance in the lignified 
walls, chiefly tinctorial phlobaphenes. 

The walls of the wood-elements are, however, not lignified 
to the same extent. The primary layer of the wall is, as a 
rule, lignified most and contains but little cellulose. In con- 
sequence, on treatment witli lignin-solvents, it becomes first 
tlissolved while the secondary and tertiary meml)ranes, althougli 
their lignin is also partially dissolved out, remain behind as a 
distinct framework of cellulose. With longer treatment destruc- 
tion of the tissue proceeds till only the pure cellulose membi-anes 
of the isolated cells remain. The ferments of many fungi act 
in this way ; for example Trametes pini, as shown in Fig. 1 2 ; 
at <i the wall is in its normal condition, showing a primary 




Fi<;. 12. —Section of tracheides of pine-wood in process of dissolution by the 
ferment of Traiuetes pini. i-J^. (After R. Hartig.) 



wall and two striated secondary membranes ; at h the fungus- 
ferment has caused a splitting of the primary wall, which 
formerly appeared as a single layer, and the elements are 
separating from each otlier ; the " filling-material " of the inter- 
cellular spaces (under c), and tlie ring of lime surrounding the 
cavity of the pit d, remain for a longer time ; the right wall 
of the cell h consists only of cellulose, (as indicated by the 
striation being no longer shown, although still present) ; in 
the cell r the primary wall has disappeared, and the secondary 
and tertiary membranes thin off towards / in which only 
the ash constituents remain as fine granules, better seen in 
Fig. 13. 

In contrast to the lignin-dissolving fungi, there are those 
which dissolve cellulose. When wood is treated with sulphuric 



EFFECT OF PARASITIC FUNOI ON THE CELL-WALL. 



39 



acid the cellulose is dissolved out, and the primary wall remains 
almost intact, while the secondary after swelling is converted 
into sugar and gum. Certain fungi {ejj. Foh/pori's mjurrarius, 
P. ' Schvjcinitzii and F. sulphnmis), act in the same manner, 
first dissolving out and consuming the cellulo.se before attacking 
the wood-gum. When wood is destroved bv funiji of this 





Fk;. 13. 



Fia. 14. 



Fio. 1 ;S. — Tnicheid of Pinui »i/ti-estris destroyed by TicniKttii iiitti. The primary 
cell-w ill is completely dissolved from liclow upwards to <i, v. ; 0, secondary and 
tertiary layers of the walls consisting in the under portion of cellulose only, in 
which Knmules of chalk are recoyiiizable ; c, fun^us-hyphae lx)rinjf throuj{li the 
walls, leaving holes <l and e. (After R. Hartig.) 

Kici. 14. — Tracheid of /•i/ikji destroyed liy I'oli/i>niu» Sclncditilzii. The cellulose 
has been extracted, and the wall consists only of wood-gum. The fissures are a 
result of drying-up, but they do not extend into the jirimary wall «, l>. Crossing 
of the fissures takes place at the Iwrdercd pits c, and at the bnre-holes it and f ; 
J, simple fissures. (After H. Hartig.) 

kind, the primary wall, containing l)Ut little cellulose, is hardly 
atlected, and the secondary membranes shrink together, so that 
numerous fissures are produced running in a spiral direction, 
corresiionding with that of the stratification (Figs. I .'> and 14.) 
The tertiary membrane varies in its nature ; it may consist of 
])ure cellulose or be more or less lignified, oi- even cuticularized. 
In the W(jod-tibies of some jilants (Ci/dsn^, J/nmi'/i's,) tliis 



40 REACTION OF HOST TO PARASITIC ATTACK. 

layer becomes normally loosened from the other membranes, and 
appears as a separate tube in the cavity of the fibre. 

Variations of this kind in the structure of the wood must of 
course influence the action of the attacking fungus. The decay 
may be a local one, as with Trametes pini, T. radiciinrda, 
Thdcphora jycrdix, which cause destruction of isolated spots 
only and produce holes here and there throughout the wood. 
On tlie other hand, the wood may be uniformly converted into 
a iliscoloured decayed mass. The walls may be simply pierced 
by little holes corresponding to the perforating hypha, or large 
portions of them may be more or less completely dissolved 
away, and either the cellulose or lignin remain behind as a 
skeleton. Hartig gives an interesting case which accompanies 
dry-rot {Mcrulius lacTymans): the mycelium adherent to the 
cell-walls dissolves out the lime granules included in the mem- 
branes by the excretion of some fluid containing carbonic (or 
other weak) acid, in mucli the same way as roots corrode 
limestone. 

The dissolution of starch in wood has already been considered. 

In conclusion should be mentioned Hartig's observation 
that normal spruce wood, on treatment with ferric chloride, 
the reagent for tannin, gives no coloration, such as is given 
by the same wood when destroyed by dry-rot. 

§ 8. EFFECTS OF PARASITIC FUNGI ON THE ANATOMICAL 
STRUCTURE OF THEIR HOSTS. 

Effects of this kind can only be looked for where mor- 
phological changes have resulted from the presence of parasitic 
fungi, particularly in the case of hypertrophied organs. Wakker^ 
was the first to collect recorded evidence of anatomical changes 
due to hypertrophy ; he added to these by his own investi- 
Lrations, and classified the results. We shall therefore in this 
division depend chiefly on his publications. 

Enlargement of host-cells is one of the most frequent pheno- 
mena accompanying attacks of parasitic fungi. It may take 
place with both intracellular and extracellular parasites. 

A single cell hypertrophied in this way is the simplest 
possible form of a "fungus-gall" (see p. 25). Examples of 

' Wiikker, Pringsheim's JnhrJnich, 1892. 



EFFECTS OF PARASITIC FUXGI ON TISSCES OF HOST. -41 

simple galls of this kind are cells of Filolndas Klriaii iiihabited 
by Pleotrachclus fulgciis, cells of turnip infested by Plasmodio- 
phora, or of dandelion with Synchytrium. 

Cell-enlargement resulting from the intlueuce of extracellular 
parasites is most distinctly seen in those algal cells, which 
form lichens with the hyphae of certain fungi. Thus according 
to Stahl, the algal cells of the lichen Eiuhicarpon im-siUinn 
become enlarged six-fold. 

(.'ell-enlargement accompanies all hypertrophy of plant organs, 
whether the parasite lives purely intercellular, or has haustoria. 
At the same time one generally finds a disappearance of the 
intercellular spaces present in the normal tissues ; in some 
special cases, however, these may become more numerous and 
larger. Cell-enlargement, accompanied by disappearance of 
normal intercellular spaces and chlorophyll, are shown by 
Woronin's illustrations to be very marked in the galls on cow- 
berry, due to U'obasidium vaccinii. Cell-enlargement is also 
frequent in cases of hypertrophy due to Exoasceae ; thus in 
Tiiphrina amxa, although the mycelium is only subcuticular 
or penetrates but slightly into the epidermal layer, yet the 
cells are much enlarged and their walls are strikingly thickened 
(Fig. 63). Smith ^ found that when leaves became thickened 
in consequence of attacks of certain species of Taplirina, their 
cells became larger and rounder, so that the large intercellular 
spaces of the spongy parenchyma disappeared and tlu- rliar- 
acteristic appearance of that tissue was lost. 

The epidermis, as has already been indicated, is intlueneed 
by fungi wliieh live between the cuticle and cell-wall, as well 
as by epiphytic fungi, whose haustoria penetrate it. The 
epidermis is, liowever, more fre([uently destroyed by endo]ihytes, 
which rupture it in forming their rej)roductiv(! organs. Some 
of these produce their s])orocarps inside the epidermal cells, 
ami, as they enlarge, cause detachment of the outer walls of 
the cells I'roiu the remainder, to foiui fur a time a covering 
whicli is ultimately ruptured as the sporocarjjS attain maturity. 
Where the fungi live under the cuticle (<■.//. the Kxoaseeae), 
this .'done is ru|itureii when the asci are formed. Tlie repro- 

' William (J. Sniilli. " UiiterHiulmng il. M<ii])li(il<>i:if u. Aiiiitoiiik- <1. Wuiili 
Kxoiisceen vermsiiclitoii Dtfdiiniitionfii. " lining. Din.st'itution, Miiiiicli, ISiM; 
alfio, FijrMf/ir/t.iiittiiriris.i. Z' ii-nhri , 1 H<(4 . 



42 REACTION OF HOST TO PARASITIC ATTACK. 

duetive inyceliuni of the following forms also grows only under 
the cuticle : Ilhytisma andromedac, the spermogonial mycelium 
of rurcinia ancvwncs, Phrafjmidium, and other Uredineae. 

In many cases of hypertrophy the epidermal cells become 
enlargetl in a radial direction, and this, as in Tctphrina aurca, 
may be accompanied by considerable thickening of the walls. 
In other cases, like that produced by Synchytrmm, the epidermal 
cells may l)ecome gelatinous. 

The cork becomes abnormally increased in many examples of 
hypertrophy. Thus in witches' broom of alder due to Exoascu^ 
qnpkijUu>i a phelloderm is formed, while on normal twigs phellem 
alone is produced. Cork is found in juniper needles with 
Gijvinos23orangiiniijuniiKrimtm, thovigh never in the normal needles. 
On the other hand, cork-formation is suppressed in twigs of 
hawthorn, deformed by Roestelia laccrata. The so-called "wound- 
cork" is constantly associated with attacks of parasitic fungi ; it 
separates diseased portions of rind and bast from sound, forms 
sheaths round bundles of sclerenchyma, . and permeates the 
medullary rays. 

Collenchyina was found by Wakker to be absent in all cases 
of hypertrophy of parts of plants where it is normally present ; 
for example, in stems and petioles of cowberry attacked by 
Exohasidiuin, stems of buckthorn with Aecidium rhamni, of 
Cratargiis with Roestelia lacernta, of nettle with Aecidium vrticae, 
and of Sauf/uisorbici with Xenodochvs carbonarius. On stalks of 
Umbelliferae with pustules of Protomyces, I found, where the 
coUenchyma region was involved, that that tissue was not 
developed (Fig. 46). 

In all eases of hypertrophy, parenchyma plays an important 
part. Most abnormal outgrowths result from multiplication and 
enlargement of the cells of the parenchyma, the formation of 
mechanical tissues being more or less suppressed. Thus the 
gigantic e.xamples of hypertrophy exhibited by turnips infested 
by J^lasmodiophora, consist almost exclusively of parenchyma. 
Thickening of stems or branches is generally due to increase 
of the rind-parenchyma, as in buckthorn under intluence of 
Aeeidimn rhamni, hawthorn with Gymnosporangium clavariae- 
formc, in most witches' brooms, and in many other cases. In 



EFFECTS OF PARASITIC FUNGI (»X TISSUES t»F HUST. 43 

the witches' brooms due to Aeciditun daiinuin, the pith appears 
enlHr<^ed as the result of increase of the medullary parenchyma. 
In diseased leaves, palisade parenchyma can frequently no longer 
be distinguished from spongy, and only irregular polygonal cells 
are formed. As examples may be given needles of tir with 
Aecidium ohietinuni, and leaves with galls due to Exoasceae. 
Finally, there may be a marked increase of wood-parehchyma, 
both of medullary rays and the wood proper ; this is especially 
well marked in Juniperus communis affected by (Ti/mnosjxmoif/iinit 
juniperinuin} where in consequence of an enormous increase of 
the parenchyma of riiid and medullary rays, the tracheidal 
regions become separated by broad wedge-shaped rays, and at the 
same time they are peripherally intersected In' bands of paren- 
chymatous tissue resulting from increased development of the 
wood-parenchyma (Fig. 220, etc.). 

The Sclerenchyma is generally suppressed where hypertrophy 
occurs. Examples mentioned by Wakker are stems of cowberry 
with Ej:ohasidiinn, uf hawthoiii with (ijpniws'poranyiv.m, of 
Sanf/uisoi^bifi. with Xenodochvs, and alder catkin-scales with 
Exoascas. On the other hand, sclerenchyma is developed in 
stems of Ciraium as a result of Pucclnia suaveolens, whereas 
normally it is absent. 

The secondary vessels of the wood frequently remain irregular, 
and with imperfectly absorbed partition-walls. According to 
Wakker, this is the ca.se in Vaccinium with Exohimdivin, 
Crntnt(jiis with Iiorsf/'lia, and Iihamnus with Airidiuin. 

Suppression of interfascicular camltium was ob.served liy 
Wakker in buckthorn and nettle with their respective Aecidium 
parasites. Prolonged activity of the same tissue he found in 
Sisymhriam with Ci/iitopiis. 

Arrest of lignification was found liy Wakker in medullary rays 
of Cratartius with lutrsfi/iti, and in deloruuMl scales ot' aldci- 
catkins atl'ected by E-nxiscus. 

We have already considered increased growth in length and 
thickness in connection with hypertrophy. It need only be 
added that increased thickness of woody ]»lants may l)e due to 
increase of the riml.the bast, the pith, tir iiuMJullaiy rays, and not 

' I'. Wiiiiilc. " Aiiiitoiiiisclie I'litiTHUcliuiig <1. tliin.li <i\ inMDNporan^'iiiiiiArtiii 
lieiVfdj^iTuffiifii MisMl)ililiiMgLii." Iiiiiug. Diss., MmuliiMi, ISS)4 ; iil«u, Furitlifh- 
iiutiini-iHi. ZiitHilirif'U ls!t4. 



44 



REACTION OF HOST TO PARASITIC ATTACK. 



to increase in the actual wood elements. This is the case in 
twigs of .silver fir witches' brooms, in young swellings of juniper 
attacked by Gi/nmospom/if/ium, and in the thickened twigs of 
Alhizzia resulting from Uroimjces Teppcricmus (Fig. 181). There 
may be, however, a distinctly increased growth of the wood. 
Thus, with attacks of Gi/mnosporangium frequenting juniper, 
especially G. sahinnc, there is often a marked thickening of 
l)ranches due to increase in the xylem-elements. Again, one 
finds cankers due to Aecidium clatinum, accompanied by stern- 
swellings with a diameter twice or three times that of the 
normal, and in which the bark and bast form but a thin layer 
in proportion to the part made up by the wood. Exceptionally 
striking are the gigantic woody knots formed on the Japanese 

Pinus dcnsijlora, and P. 
Thunbergii affected by Pcri- 
dcrmiuvi giganteum (Fig. 
15). 

Wakker found that mu- 
cilage canals of Bharnnus 
Frangula affected by Aeci- 
dimn were not so well 
developed as in normal 
twigs. 

liesin-canals are often 
irregularly formed and al)- 

Fio. 15. — Wood-swelling on Pinus deiuifioru, attacked nomiallv multiplied ill COll- 
um. h natural size. "^ 




at this place by Feridermium gigante 
(v. Tubeuf phot.) 
(On Pinus T'/iiui'jcr^u still larger examples may occur.) 



sequence of parasites. The 
resin-canals of the spruce 
were found by Hartig to be so numerous in plants attacked by 
Agariciis melieus that an abnormal quantity of resin is produced 
in the wood, and flows from the diseased roots ; hence has 
arisen the name " resin-glut " or " resin-flux " by which the 
disease has long been known. A particularly noticeable flux of 
resin takes place from pine-bark in presence of Peridcrmium 
pini ; the mycelium grows in the medullary rays and resin- 
canals, causing an excretion of resin from all living parenchyma 
in the wood, so that both bast and wood become completely 
impregnated with resin, and thin sections of wood transmit a 
rose-coloured ]vj]\t. 



CHAPTER III. 
RELATION OF PARASITE TO SUBSTKATUIM. 

§ 9. EFFECT OF THE SUBSTRATUM ON THE DEVELOPMENT 
OF THE PAEASITE. 

A NUMBER of parasitic fungi live only on one species of 
host. For example Sclerotinia haccarum on Vacmiium Myrtillv.s, 
Chrysomy-ra abietis on Ficea cxccha, Trii^liragviium idmariae on 
Spiraea ulmaria, Hysterium nervisequium on Abies ^jcc^iiwrt^a, 
Rhytisma androvudae on Andromeda jJoH/olia. De Bary^ proposed 
for cases like this the term monoxeny, while to cases in which a 
parasite frequents several difierent species of host he gave the 
name polyxeny, or more particularly, dixeny, trixeny, etc. As 
examples of polyxeny may be mentioned lihytmna saliciiunn 
found on all species of willow, and IiJtytisma aen-inum on the 
genus Acer. Other parasites attack not only different species 
of some genus, but also different genera; thus, Fucrinia y/mninis 
occurs on various cereals and grasses, Fhytirplithora oinnivora 
on many different plants, Fhyllaetinia svffulta on leaves oi" 
Corylus, Fay us, and many other trees; Clarieeps pi/z-jyurea on a 
large number of cereals and grasses, Cysto2)us candidits on many 
Cruciferae, and Nectria civnabarina on all kinds of broad-leaved 
trees. 

Monoxeny and polyxeny must be carefully distingui.-^hed from 
the autoecism and heteroecism of the Uredineae. Many species 
of this group go through their whole life-history, and produce 
all their forms of spore on the same host, others, iiowever, pro- 
duce some forms of spore — spernuitia and aecidiospore.s — uu ime 
host, and the n-niaintler — uredospores and tdtutospores — on 

^ flo/fUtiirhr Z>ifuil<l, ISOT, p. I'til. 



46 RELATION OF PARASITE TO SUBSTRATUM. 

another liost. Such heteroecious parasites may be, however, also 
muuoxeiious ; for example, Mdampsora Goeppcrtiana has its 
teleutospore-form only on the cowberry, its aecidium-form 
tjnly on the silver lir. On the other hand, Chrysomyxa 
i-lwdudcmli'i frequents several species of Rhododendron, while 
the aecidia occur only on Ficca e.ccelsa ; Crondrtium asdepiadeum 
conies on both Gcntiana and Gynanchum, the aecidial stage 
only on PinuH sijlvestris. With Gyinnosporangium davariacformc 
this condition is reversed, the teleutospore-form occurs only on 
Jiniiprrus cohimunis, the aecidial on various species of Crataegus 
and other genera. 

The effect of various suljstrata on the development of any 
fungus may be most conveniently investigated : {a) on facul- 
tative parasites and saprophytes, {h) on polyxenous species of 
fungi, (c) in cases where the fungus inhabits essentially different 
organs or tissues of the same host. 

The most obvious effect of the substratum is presented during 
the germination of spores. The spores of most parasites ger- 
minate in water. Those of certain smut-fungi, especially in 
the fresh condition, will not germinate at all, or only to 
a very limited extent in water, whereas they will do so 
immediately and unanimously on being offered a nutritive 
solution. TiUctia, a genus of Ustilagineae, behaves, however, 
in quite the reverse way, it germinates only in water, and 
refuses to do so in nutritive solutions. Hartig found that the 
spores of dry-rot {Mcr alius) would neither germinate in water 
nor in the usual nutritive solutions, but that they did so at 
once on adding alkalies to the water, such as those supplied 
by addition of urine. Very characteristic is the behaviour 
of these spores, which only germinate in contact with their 
host-plants, like many Chytridieae ^ {Syndiytrium), as well as 
Complctoria and Protomyces} Others again send out germ-tubes 
which remain small and soon die away if an inniiediate 
<jpportunity of penetration into a host is not presented. De 
Bary states this to be the case with swarm-spores of Cystopus, 
Peronospora nivea, Erysipheae, etc. Amongst the Uredineae, the 
germ-tubes are short-lived; they will penetrate into almost any 

' De Bary, Morpholo(jy and Biology of the Fuiuji, chajj. vii. 

-An exactly parallel case is presented by the seed of Orobancheae, which 
i,'ernnnate only in contact with the roots of their host (Koch's " Orobanchen," 
Heidelberg, 1887). 



EFFECT OF SUBSTRATUM ON DKVELOPMENT OF PARASITK. 4< 

host, but soon die oft', if it be not a suitable one. l)e l>aiy 
also observed a germ-tube of Fcronospora jji/ijuw.ca, which 
frequents Anenione, making its way into lianunculus Ficaria, 
but soon to die. Germinating spores of CUjstopas candidu.s will 
enter the stomata on leaves of any of their host-plants, especially 
Cnp>idla, but will only develop further if they are successful 
in penetrating into the cotyledons. 

Variation in the substratum produces very great difference in 
the formation of the reproductive organs. Thus many Ustila- 
gineae produce conidia by continuous sprouting only when 
cultivated in nutritive solutions, while their resting-spores are 
developed only from a mycelium which inhabits the reprculuctive 
■organs of their host ; this is the case with Ustilago caricis, 
U. anthmrum, and U. tritici. In others the spores are found in 
all parts of the flower, and even in the inflorescence, as in 
Ustikufo crucnta and U. tragojMgonis, while in Ustili'f/o huu/<Us 
spores are also produced in leaves and stems. 

The various parts of the same plant behave very differently in 
this respect. The Ustilagineae just considered reproduce them- 
selves only on certain organs of their host, although the 
mycelium is also present in other organs. Other fungi behaving 
similarly are Epichlo'e typhinn which produces its perithecia only 
on the surface of the sheath of one of the leaves just below the 
inflorescence; Accidiuni rhdinum develops its aecidia only on 
the needles of the witches' broom ; Aecidiuiii enphorhiac has its 
aecidia only on tlie leaves of its host; F.ioascus pnaii has asci 
only on the fruit ; Cabppto-^pora produces teleutospores in tlie 
■epidermal cells of the stem, never of the leaves ; and so on in 
many other cases. 

The formation (jf oogcjnia of C/jstopus exhibits a striking vari- 
ation according to tlie host-plant. Ci/stopus caiididus on Capsclla 
produces conidia alone, never oogonia ; yet the latter are plenti- 
fully developed in flowers of Jjrftssird, being conHned, however, to 
the flowers, wliile conidia are pnichiccd in all parts. Ci/sfopus 
hi Hi forms conidia only in the leaves, and oogoniit only in the 
stems of Ahinrdiitlius hlituni} 

The mycelium of many oilier fuiiui cm only ;j:niw in certain 
(jrgans, while germ-tubes from the spores are only able to pene- 
trate into certain parts of the host. Thus, K'OKsriis ulni inrinia<- 
' De Bury, Morpholoyy iiml Hioloiiy <>/ tin Fuiv/i, Kiiglisli Kditii'ii, \>. .Sill. 



48 RELATION OF J'ARASITE TO SUBSTRATUM. 

has a mycelium only in catkin- scales ; Exoascus irruni, however, 
hibernates in the twigs, and forms reproductive organs only in 
the walls of the ovary ; Aecidium strubilinum grows only on the 
cone-scales of spruce; Clavice2)s frequents only the young ovaries 
of cereals and grasses ; and so on, other fungi inhabit only leaf, 
stem, root, or Hower. 

In this connection points of considerable interest are presented 
bv the behaviour of many Uredineae hitherto little investi- 
gated. As was pointed out by De Bary, the germ-tubes 
produced from both uredospores and aecidiospores (in Puccinia 
dumtln those from sporidia also), penetrate into the* stomata 
of any phanerogamous plant. If, however, that should not be 
a host-plant of the fungus in question, then the germ-tubes 
die away in the stomatal air-cavity. If the host suits the 
fungus only in a limited degree, then no hypertrophy will 
result, and the latter will attain only to the formation of spermo- 
gonia. Let the host, however, be the one best suited to the 
fungus, then hypertrophy will result and aecidia be developed. 
Very conclusive evidence of this interesting condition has been 
furnished by numerous experiments which I have carried out 
with spores of Gymnosporangmm} If one infects Crataegus 
Oxyacantlia with G. clavariaeformc, very marked stem-hypertrophy 
results, even by the time the spermogonia have made their 
appearance ; there is also considerable swelling of leaves and 
slight enlargement of cotyledons, while aecidia are produced 
in numbers everywhere. When the same fungus is used to 
infect Pyrus Auc^iparia, no yellow spots or malformation 
of any kind results, and spermogonia, hardly visible with a 
lens, are formed only here and there. A similar infection on 
Pyrus latifolia (P. Aria X torminalis) results in a crop of 
badly developed aecidia. If quince be infected, then without 
any hypertrophy whatever, little red spots bearing numerous 
spermogonia are formed on the leaves, but the development of 
the fungus ceases there ; on the death of the quince leaves, 
the chlorophyll is retained in the immediate neighbourhood of 
the spermogonial spots, so that they remain for some time as 
green islands on the yellow leaf. E. Hartig's infections with 
Mclamjysora trnnulae also led to varied results ; on Pinus there 
ensued a distinct disease of the cortex (Caeoma innitorquum),. 

' V. Tuljeuf, CeiitralblaU f. Bacteriologic u. Parasitenkunde, 1891. 



EFFECT OF SUBSTRATUM ON DEVELOPMENT OF PARASITE. 49 

while on Larb: only little cushions appeared on the needles 
( Caeoma laric is). 

These variations in tlie effect of the substratum on the 
development and reproduction of the parasites assist us to 
understand the well-known resistance of certain varieties and 
species against epidemic diseases, which are sweeping oft" their 
near allies. Thus, we know that some varieties of cereals sufter 
from attacks of rust-fungi more than others grown under like 
conditions. Similarly amongst the varieties of vine some are 
known to be more sensitive to disease than others. These 
points will be more fully discussed in a subsequent chapter. 



CHAPTER IV. 
NATUEAL AND ARTIFICIAL INFECTION. 

§ 10. Ill artificial infection we have a safe mode of distinguishing 
whether a fungus is parasitic or not ; in other words, whether 
it is capable of penetrating into the organs of living plants. 
This method of investigation should always be resorted to in 
determining the cause of disease, more especially if mycelium 
or sporocarps of several fungi are present on the diseased 
material simultaneously. For it not unfrequently happens that 
the disease has made so much progress as to make it quite 
impossible to determine whether or not any fungi present on 
the dead remains are really the cause of disease. In many 
cases where one finds a mycelium in living parts, it has 
disappeared, and only sporocarps remain in portions already 
killed. 

Injuries due to insects frequently accompany fungi on a 
diseased plant, so that it is extremely difficult to say which was 
the primary cause of the damage, and artificial infection must 
be resorted to. So also with injuries from some external source 
like drought, heat, cold, moisture, and mechanical causes. 
Fungi appear so soon after hurtful agents like these, that it 
becomes doubtful whether they are the cause of the death of 
the host, or the result of it. 

Minute observations in situ of all the circumstances connected 
with the attack, combined with examination of numerous speci- 
mens and comparison with neighbouring plants, enable one, 
after some experience, to say with a fair degree of certainty, 
whether the disease in question is of fungoid origin or not. 



XATLKAL AND ARTIFICIAL INFECTIUN. 51 

The exact proof, however, is best obtaiued by means of experi- 
mental infection. 

With many parasites the sporocarps are normally developed 
saprophytically on a dead substratum, so that if parasitism 
be suspected it can only be proved by infection. Thus the 
perithecia of Nectria ciinmharina develop only after the death 
of the plant-organ, which the fungus attacked when alive. The / 
more complex reproductive organs of many fungi are developed 
only on dead remains of the host, while on living or dying 
parts one finds various forms of conidia of doubtful relation- 
ship. In many cases it has been possible, by means of artificial 
culture alone, or combined with artificial infection, to prove 
various forms of reproductive organs to be stages in the life 
of the same fungus. 

When a group of fungi contains both saprophytes and parasites, 
it is often necessary to determine whether some species is para- 
sitic or purely saprophytic. This is particularly the case with the 
groups of Pyrenomycetes, Discomycetes, Hymenomycetes, several 
groups of the lower Fungi, the Bacteria, and Myxomycetes. It 
is unnecessary, however, with the Uredineae, Ustilagineae, Per- 
onosporeae, Exoasceae, and other groups known to contain 
parasites exclusively. 

But even in these last-mentioned groups experimental in- 
fection is necessary for obtaining information on other points. 
The reproductive organs of Uredineae cannot be reared in 
artificial solutions, so that their cultivation must be carried out 
on the living host-plant. In this way alone can we ascertain * 
the relationship of ureddspores, teleutospores, and aecidial-forms, 
where any doubt occurs as to their belonging to the same 
species. Infection becomes particularly valuable when one has 
to investigate heteroecious Uredineae, whose various forms of 
reproductive organs inliabit several iiost-plants. Thus ii was 
by means of infection that De Bary discovered the connection of 
Accidinm hcrhrruUs on the barberry, and I'lurinid (jnoni/tis on 
•cereals ; likewise Hartig, the n-hitionshi]) of }[>himpfiora (}i» p- 
jhrtuinH on cowljeriy with Aiciiltn.in i-ul n innmr on needk's of 
silver fir. 'J'here still remain many aecitlia, tek'Utospores, ami 
uredospores, wiio.se related f(jrnis have not yet been ftiuml. 

Infecticuis are als(j necessary to deti'rmine the species of a 
lungus. It has been found, for example, that (iijmniisponiiujiuin 



52 NATURAL AND ARTIFICIAL INFECTION. 

confusum and (r. sahinnc may, in their aecidial stage, be dis- 
tinguished as two species inhabiting distinct hosts — Crataegus and 
pi/rus respectively — whereas, in their teleutospore stage on juniper, 
they scarcely vary. In infection we have an important aid in 
determining the host-plants of the various forms of heteroecious 
funrri, and in this wav it has been found that the same fungus 
behaves differently according to the host-plant on which it 
is present. Thus, in the genus Gymnosiwranfjium, I have found 
that a certain species had well-developed aecidia on one plant,, 
poorly developed ones on another, while on a third only spermo- 
gonia api)eared. Similarly, in that case already mentioned, 
Hartig found the Melam2)sora of the aspen to produce on the 
pine a disease of the cortex, accompanied by marked deformation, 
while on the larch the symptoms were mere inconspicuous aecidia 
on the needles. 

Amongst the Ustilagineae, experimental infection is necessary 
to determine whether the natural infection of host-plants results 
from germinating spores (chlamydospores), or from germinating 
conidia (sporidia). Kiihn was able by this means to demonstrate 
exactly that the spores of Ustilagineae j^roduced germ-tubes 
capable of direct infection. Brefeld succeeded in observing the 
penetration of germinating sporidia into a host-plant. In this 
way he proved, amongst other facts, that maize may be attacked 
by Ustilago maydis on any young part ; also, that the mycelium 
remained local. Oats, on the other hand, could only be infected 
by Ustilago avcnac at the neck of the young seedling, and the 
mycelium extended through the plant till it reached the inflor- 
escence, where the spores are formed. 

In the case of the Exoasceae, two points were cleared by the 
aid of artificial infection — the penetration of spores into leaves of 
host-plants, and the production of witches' brooms. Sadfebeck,^ 
by means of infections of JSxoascKS qnjjhgnus on Alnus incana, has 
produced witches' brooms artificially, thus proving that these 
malformations really originated from the mycelium of Exoascus. 

It is by infection-experiments that one determines into which 
part of a host the germ-tubes penetrate, whether into leaf, flower, 
fruit, stem, or root, and also whether it passes through the 
epidermis, or l)etween two adjacent epidermal cells, or through 

' Kritiache. UntersuchiuKjen i'ther d. durch Taphrina herrorijelirachten Baitm- 
kranhheiten, 1890. 



JJL" _i_'i.!'.-i if^ji JJi J-^ : 



NATURAL AND ARTIKRIAL INFECTION. 53 

the stomata. Also, whether the genu-tiibe formed from a 
germinating spore penetrates direct, or if, as shown by I)e Bary 
for Sderotinia, a mycelium vigorous enough to penetrate must 
tirst be developed saprophytically. 

Ill this connection De Barv ' states tliat tlie germ-tubes fnmi all aecidio- 
spores and uredospores only penetrate by stomata, and thence extend through 
the intercellular spaces. Entry through the stomata has also been observed 
on the germ-tubes from s]joridia of Leptopucciniu dktn(/ii, aik\ from spores of 
Entyloma. On the other hand, germ-tubes from the spores of teleutospores, 
from spores of Perouosporeae, Ustilagineae, Sderotinia, Polystigma, Pro- 
tomyces, and Sj/nchi/trium effect an entrance through the outer cell-walls into 
the epidermal cells or stoniatal guard-cells. De Bary also describes the 
peculiar l)ehaviour of zoospores of Cystopns and Peronosporn umbelh'ferarnm, 
which, if they come to rest near a stoma, germinate, and the germ-tube 
enters therein, whereas one developed in water soon dies. Certain fungi 
jienetrate sometimes through the membrane, sometimes by a stoma, e.g. — 
Plq/tophthora infestans, Peronospora parasitica, Exobasidinm vaccinii. 

In the case of Phytophthora omnicoru, Hartig found that the germ-tubes 
from the zoospores crept along the surface of the leaf till they reached a 
place where two epidermal cells adjoined ; there they entered, and only 
rarely grow into the epidermal cells. The germ-tuljes of Protomyces macro- 
■yjoriis and Tubiircinia trientalis enter their hosts in the same wav. 

From experiments, one is able to determine the conditions 
favourable, or (jtherwise, to infection by i)arasitic fungi; to ascertain 
ihe inriuence of temperature, air-moisture, water-content of the 
host, hairiness of the leaves, and the effect of resin or other 
excretions as protections to wounds. For example, it was in 
this way that Hartig found Scdlc piilrltm {pruinosd x dapJmoufr.s) 
to be a hybrid which, on account of its hairy leaves, is more 
resistant to Mclami)mra than Salir 2)n'in(>s((.~ Much investiua- 
tion remains yet to be done in this direction to ascertain what 
varieties or species of cultivated plants are likely to be least 
liable to attack by epidemic diseases.-' 

The methods used in carrying out artificial inlectiou are 
based oil the observation of cases of natuial inlcctidii. .Most 
l'itM[uenlly infection is peiforiued by means of spores, less often 
with mycelium. 

The spores of lower forms of fungi arc generally ilistribiitcd 
l»y me;ins of water, especially in dew or rain. Zoospores are 

' Morphuloijy ami Jiioloijy of I hi- Fuiii/i, Knglinli Kiliiimi, |i|i ;«»l-.'I(j'_». 
-Hartig, DinfaMm of Trim, KiigliHli Kditiou, IS'M, p. 171. 
^See ('liajjter V. on " ! )ispositioi)." 



54 NATURAL AND ARTIFICIAL INFECTION. 

completely adapted for distribution in water. Amongst the 
liigher fungi, spore-distribution almost always takes place by means 
of wind. Insects as agents are rare, although one does occa- 
sionally find special adaptations intended to secure their visits. 
The spores of many fungi are forcibly ejected from the sporo- 
carps, asci, or sporangia ; some of the many arrangements which 
ensure this will be given in the special part of this book, others. 
will be found in the works of Zopf,^ and De Bary.^ Ludwig, 
in his text-book,^ points out that the spores of many Ustila- 
gineae frequenting entomophilous flowers, are provided with 
ridges and spines, which are probably an adaptation to their 
transportation by insects; smooth-coated spores are more common 
on leaves, stems, and organs other than the flower, and are 
evidently distributed by the agency of wind. 

The mode of distribution and infection is quite apparent in 
many fungi. Thus in the oat-smut {Ustilago aveiioe), the 
diseased ears in a field rise above the sound, so that the light 
dusty spores are shaken out in clouds by the slightest wind ; 
they hibernate on the earth or on straw, and germinate in 
spring to infect the oat-seedlings at the base of the stem. 
Equally simple is the distribution of spores and conidia from 
one plant to another by wind during summer. Good examples 
of this mode are the conidia of the Erysipheae, and the 
aecidiospores and uredospores of the Uredineae. Thus, the 
yellow spores of Chrysomyaxi rhodochnclri, when the aecidia are 
present in very large numbers on the needles of spruce, 
may cause the phenomenon known as " sulphur-rain." It is 
well known that this is generally due to the yellow pollen of 
conifers caught and carried to the ground in show"ers of rain, 
but E. Hartig describes a case observed by him near Achen-see 
(Tyrol), where objects were covered by a yellow dust, consisting 
exclusively of spores of Ckvi/sovup'a. Spores of this kind are 
capable of transport to very great distances, so that heteroecious 
species can still keep up their connection even though by no 
means near each other. 

Aecidiospores of all kinds are distributed more by wind than 
by insects. In rare cases, however, the aecidia have a sweet floral 

'Zopf, Die Pike, 1890, p. .349. 

^De Bary, Morphology and Biology of the Fungi, English Edition, 1S87. 

^ Lehrbuch d. niederen Kryptogamen, e.g. p. .S70. 



NATURAL AND AHTIFICIAL INFKCTIoN. 55 

odour, c.fj. Aec. odoraturn in America. The wind we must also 
regard as the distributor of uredospores and of the sporidia of 
germinating teleutospores. The Uredineae have typical spores 
for distribution by wind with the exception of the so-called 
spermogonia. These structures are produced by most l^redineae, 
generally on the upper surface of the leaf and before the aecidia; 
they are brightly coloured, and give out spermatid in a sticky 
gelatinous slime, frequently with a distinct odour. Thus they 
seem to be admirably adapted to transport by insects, and are 
in fact visited by them. Their distribution, however, has little 
importance, since they are, as far as known, incapable of 
germination. They are regarded by many as degenerate forms, 
either of male sexual organs, or of pycnidia. Some of the 
spermatid have been made to germinate in artificial culture, 
but of their incapacity to germinate in natural surroundings 
there can be no doubt. 1 am not aware of any one who 
has succeeded in bringing about infection with these spermatia, 
but I have tried it often with no result. 

It is much more difficult to ascertain how fungi, which 
t hibernate on the earth, find their way in spring to their 
respective host-plants, in some cases even to the crown of very 
large trees. Amongst such forms one frequently finds an 
arrangement by wliieh the spores are forcibly ejaculated. Thus 
Rhytisma a.cerinani, which reaches maturity only in spring after 
hibernating on dead sycamore leaves, and Sch:rotinia bctulae, 
which does so on fallen fruits of birch, both have their spores 
forcibly ejaculated and carried otT by wind. Klebahn states 
that the ejaculation takes place in dry weather, and that the 
spores of Ehytisma are prevented from drying up by a gela- 
tinous covering. In a similar manner the hibernating spores of 
P>ysipheae on fallen leaves must be carried up again l)y wind ; 
so also those of Folystif/ma, which ripen on the ground and then 
infect young leaves of plum and cherry trees. 

Infection by means of the mycelium generally occurs where 
the mycelium lives in the eartli. Thus, the hy})hae of Tmmctes 
radicipinid grow lajtidly from one root to anotlier, causing a 
centrifugal spreading of the fungus, so tliat forests attacked l)y 
it have tlie trees killed oil' in ])atches. Mycelial infection is still 
more effective in fungi like Ayaricns iml/n/s which assume the 
form of rhizomoriihs. Infection by means of the mycelium may 



56 NATURAL AND ARTIFICIAL INFECTION. 

also occur amongst species of fungi living above ground. Thus 
the mycelium of Botrytis spreads from plant to plant, and on seed- 
lings in hot-beds, may form felted masses. Similarly the mycelia 
of Erysipheae, of Trichosjjkaeria, and of Hciyotrichia make their 
way from one part of a plant to a neighbouring part in contact. 

Artificial infection may be carried out by means of spores 
or by mycelium. In the case of sv^^arm-spores, the operation 
can only be conducted in a damp chamber and on well- 
moistened leaves. Thus, young plants of beech must be well 
sprayed, then infected with conidia of Pliytophthora omnivora, 
and placed under a bell-jar to prevent drying up. In this and 
many other similar cases one finds that while the spores require 
moisture to ensure germination, yet the germ-tubes easily leave 
the water-drops and penetrate into the leaves ; in other words, 
the living leaf exerts a greater influence on them than the water, 
the chemotropic stimulus is stronger than the hydrotropic. 

The spores of the lower fungi are best isolated by the aid 
of a lens or microscope, then washed on to the place to be 
infected. In the case of Ustilagineae and Uredineae the same 
method is used, except that dry powdery forms of spore are # 
simply dusted on to the host-plant to be infected. When spores 
of Ustilagineae are being used the addition of excrement of 
some sort is frequently of advantage, since it promotes better 
germination and the formation of conidia capable of infection 
after it is exhausted. One must also pay attention to the fact 
that some smut-spores can only infect the base of the stem or 
parts in process of elongation, while others can only attack 
^parts of the flowers. The teleutospores of the Uredineae must 
first be germinated in order to obtain the sporidia with which 
infection is carried out ; this generally takes place in water. 
Thus with species of GyniTiosporangium it will be found best to 
mix the whole gelatinous mass of teleutospores with a little 
water in a shallow glass dish, and to ascertain, by microscopic 
investigation after a few hours, whether any sporidia have been 
produced. If this be the case, the gelatinous mass is thoroughly 
broken up, more water added, and the yellowish water sprinkled 
over the host-plant. Care must, however, be taken that the 
larger portions of the teleutospore-mass are not left on the 
leaves, otherwise death of the latter will occur at these places 
without inft'ction taking place. For a similar reason it is not 



NATURAL AND ARTIFICIAL INFECTION. 57 

advisable to lav portions of diseased leaves directly on liealthy 
ones, it is much better to place them near each other in a 
moist chamber, hanging the former over the latter. 

When infection is carried on out-of-doors, it is best to obtain 
a small plant which can be accommodated under a bell-jar. If 
this be unattainable, it is often possible to bend one of the lower 
branches down to the ground or other support, so that it can be 
covered with a bell-jar. Again, a branch or portion of it may be 
first sprinkled, then bound loosely up in a parchment-paper. 
When carrying on infection it is of importance to avoid very 
hot and dry or cold days ; moist, warm and cloudy days, or close 
still nights, will be found best. In the case of diseases of the 
rind, it is generally necessary to wound the periderm by a few 
fine knife-cuts, then to place thereon a few drops of water with 
infecting spores su.spended in it. 

Artificial infection by means of mycelium is generally 
attained by placing a diseased portion containing living my- 
celium in contact with the healthy, so that the mycelium can 
grow fritm the one to the other. Thus, with bark-diseases, a 
small portion of diseased rind is cut out and fitted into a 
corresponding incision in the rind of the plant to be infected, 
the oculation or graft being then protected against drying up by 
gutta-percha, tree-wax, or parchment. The ingrafted portion 
need not fit very accurately if well bound up, because tlie 
mycelium will grow well in the moist chamber so formed. The 
most vigorous mycelium is generally found on the boundary be- 
tween healthy and diseased parts, so that i)ortions from this 
region should be selected for infection. 

If the fungus under investigation frequents the wood, it is, as 
a rule, a wound-parasite, so that for its infection the wood must 
be laid bare, and a diseased portion applied to it. if a branch is 
to be infected (r.y. with Nectria, or Chicurhitaria), then it should 
be cut over a l)ud, the exposed end split, and a fine wedge of 
diseased wood inserted, the whole being bound up. It is also 
possible to graft a diseased branch on to a healthy. In thr 
ca.se of stems, a portion of the healthy one should be removed, a 
diseased piece inserted, and the wound closed <»ver witli grafting- 
wax or clay. 1're.ssler's growl b-bort-r may in such eases be 
u.sed with good results t(j obtain a (vliudcr nf diseased wood, 
and to make a suitable receptacle for ii in ihc .souml jilanl. 



CHAPTER V. 
DISPOSITION OF PLANTS TO DISEASE. 

§ 11. We must here distinguish between an internal or 
inherent disposition dependent on the constitution of the living- 
protoplasm of the host-cells, and an external or accidental dis- 
position arising from anatomical peculiarities or from the con- 
ditions of environment. 

The condition of inherent disposition has as yet been little 
investigated. In many cases it must be allowed that resting 
cells are more disposed to disease than those in full activity 
of life. Thus De Bary,^ basing his conclusions on the observations 
of Davaine and Brefeld, points out that various species of Mucor, 
Penicillium, and allied forms penetrate into ripe juicy fruits, 
and remarks : " Observation of the fruits shows that' the fungi 
develop more easily, the nearer the vital powers of the plants 
attacked are to their lower limit, and at this point the conditions 
of saprophytic vegetation make their appearance." ^ Davaine 
also found that the vegetative organs of several succulent plants 
show the same phenomena as the fruits. As further examples 
may be mentioned that fungi can frequently penetrate withering 
plant-organs while they could not infect the fresh living tissue. 
Hartig observed on Peziza Willkommii that the mycelium of this 
bark-parasite advanced and killed the tissues only while the host- 
cells were in a condition of vegetative rest, not during their 
active period. 

^ Morphology and Biology of the Fungi, English Edition, p. 380. 
^Wehmer (Beitrdge z. Kennt. einheimischer Pilze, Jena, 1895), has contributed 
new facts to this subject, which are referred to later. 



DISPOSITION OF PLANTS TO DISEASE, 59 

Hartig ^ also found tliat Ayaricvs mrUcvs, in penetrating intu 
stools of oak, only killed those cells which, as it were, rested, 
whereas the cells of parts in communication with stool-shoots 
are not attacked. Likewise, Schwarz states that the mycelium 
of Cenaiujiinn o.hictis only extends through pine-shoots at a time 
when there is little vegetative activity. 

Accidental disposition depends largely on the nature of the 
epidermis enclosing plant-organs. The stems of many plants are 
])rotected from intruding fungi from the time the epidermis is 
replaced by a corky layer, still better after a bark is formed. 
Hence young shoots are in a condition of greater disposition 
than older ones. There are, however, various grades of dis- 
position to be observed, even when a simple epidermis forms 
the only covering, as is the case with most leaves, flowers, and 
many fruits. The newly-formed epidermis is, as a rule, most 
disposed while its walls are still delicate and uncuticularized, 
hence many organs are exposed to attacks of fungi only in their 
youngest condition. It is easy to infect and kill young leaves, 
and .shoots of conifers with Botrytis Bovglasii, whereas older 
needles will remain quite unharmed. Similarly with Chrysomyra 
rhododendri on spruce-needles, Cahjptos'pova Goejq'urtiano on 
silver fir, and others. Flowers are also more easily infected 
in the young stage, e.g. cones of spruce by Aaidhim st/vhilinvm. 

During early youth plants are insufficiently protected from 
great cold and drought, and also from infection by parasitic 
fungi. This may be because the young non-cuticularized walls 
offer less resistance to the germ-tubes and haustoria, or because 
they are more permeable to any ferment excreted by the fungus. 
Organs developed late in the vegetative season resemble those 
in the spring-condition in that they have not as yet matured, 
and are but poorly i)rotected against extremes of temperature, 
or attacks of parasites. 

The C(jndition of disposition n)ay be easily promoted l'i>r 
purposes of artificial infection, liy cultivating the host-phuits in 
a moist cliamber, or under a bell-jar. The same condition 
may easily arise in glass houses or hot-beds, lience ont^ lins. by 
means of constant ventilation, to guard again.^t it. 

Many diseases of seedlings {e.g. Pliytophthora omuivora, 
find /'////liinii) arc only to be feared so long as the stems of 

' ForM/l.-naturirtHM. Zeiturhri/t, 1.S94. 



60 DISPOSITION OF PLANTS TO DISEASE. 

their hosts are unprotected by cork-formation. Plant-organs 
rich in water are in a condition which disposes them to attack, 
niiali more than drier parts. The younger parts of any plant 
are more disposed than older parts. Thus in a spruce-hedge 
with young shoots appearing at different times, only those 
shoots will be liable to attack, which are young at the time 
of the scattering of the spores of Chrysomyxa abietis, or other 
spruce-fungus. De Bary was of opinion that plants of Gapsella 
were disposed to attacks of Cijdoinis candidus, only as long as 
they retained their cotyledons, because only those spores ger- 
minating on the cotyledons form a mycelium which ultimately 
finds its way through the plant, whereas plants which had 
already lost their cotyledons at the time of infection were 
in no danger. Many of the Ustilagineae attack cereals only 
when these have just emerged from the soil, infecting the 
young stems on the first sheath-leaf, whereas older and more 
advanced individuals are exempt. While all plants with a 
delicate epidermis or corky layer are liable to disease, yet some 
are more so than others. This is exemplified by the different 
powers of resistance to disease, or insect attacks exhibited by 
nearly allied forms of our cultivated plants, e.g. vines ; a differ- 
ence probably due to some variation in their outer membranes, 
such as is further demonstrated by thick-skinned potatoes being 
more resistant to disease than thin-skinned. 

Disposition is often due to external circumstances. These, 
however, act rather in presenting favourable opportunities for 
infection by germinating spores, than by directly disposing the 
plant to disease. Thus prolonged wetting of a leaf from rain 
favours germination of spores, and at the same time by softening 
the leaf, facilitates penetration of the germ-tubes. Stahl ^ has 
pointed out that leaves on which water remains for any length 
of time, present greater opportunity for growth of saprophytic 
epiphytes or for infection by parasites, than leaves with a 
smooth surface or of a shape which facilitates ready escape of 
water from their surface. It is also well known that larches 
in damp situations suffer more from Peziza Willkommii than 
those in drier places, the fungus-spores maturing and germinat- 
ing only in moist air. Similarly, moist weather or damp 

' " Regenfall w. Blattgestalt, " Ann. du Jardin hotan. dc Buitenzonj, xi., 1893, 
p. 124. 



DISPOSITION OF PLANTS TO DISEASE. 61 

situations favour reproiluction of mildew and other diseases ; 
under such conditions a rapid increase of potato-disease during 
July is easily (Jljservable and may be safely foretold. 

The extension of Hei-potricMa is greatly facilitated by snow, 
which weighs down young plants or branches of spruce and 
pins them to the soil, where the fungus develops on its host 
under the snow-covering. On this account elevated situations 
and hole-planting render the spruce liable to disease. 

]\Iany plants which, as a rule, suffer from fungus-diseases 
will be found to remain exempt in open or dry situations, or 
during a dry period. The tops of trees are not attacked by 
many fungi whicli frequent the lower parts of the crown. This 
is particularly the case with epiphytic lichens and certain fungi, 
which require a high degree of air-moisture. Tricho.yjhaeria 
jMrasitica, always very abundant in damp silver fir regenerations, 
is almost absent from free-standing trees, or from the higher 
parts of the crown in closed forest. It is, in fact, a parasite 
well adapted for extension in the crowded masses natural to 
the early growth of the fir, and the host is, during its youth, 
disposed to disease from this particular parasite. A fungus on 
the beech behaves similarly, occurring in IJavaria only in the 
very damp parts of close high forest and in Alpine gorges. 
Other fungi have better means of protection against ilrought, 
for example, Hystcrium mcurosporium has its spores enclosed in 
gelatinous envelopes and may be found on the highest point of 
the spruc^, although, on the whole, its distribution is most 
favoured by moisture. Fungi which frequent algae, or are dis- 
tributed by means of zoospores, depend absolutely on moisture ; 
hence they frequent hosts growing on banks of streams, places 
liable to flooding, ox low-lying moist meadows, whereas the same 
host-species remains completely exempt from their attacks in a 
dry locality. 

A plant may be said to be in a cundiiiou ^^'i almnrnial 
disposition to disease when deprived nf its natural protection. 
Thus wounds of any kind render a plant disposed to infection 
from wound-parasites, which are unable to harm uninjured parts. 
After .severe hail-storms an outbreak of Nrctrin <Utissitn<i is not 
iinfreiiuent amongst regenerated beech, or even in the canopy 
of older forest. I have also observed an extensive outbreak of 
Cucurhitaria hihunii on laburnum near Munich, obviouslv ilue 



62 DISPOSITION OF PLANTS TO DISEASE. 

to hail. Juicy fruits whose epidermis has become broken, soon 
rot unless a protecting layer of wound-cork is rapidly formed. 
Wounds in the wood present an entrance-gate to numerous 
Polyporeae, otherwise unable to penetrate. In the case of 
wounds to the wood of spruce or young branches of pine, a 
protecting crust is frequently formed by the rapid excretion 
of resin from the injured surface.^ 

The disposition of a host-plant depends then on some inherent 
condition of the protoplasm or on some accidental circumstance. 
The latter may be anatomical and due, for example, to thickness 
or other property of the cuticle, or to a hair-covering ; it may 
be morphological, from some defect, say on the part of the leaf 
in not allowing easy escape of water. The disposition may be 
periodic {e.g. in youth or at flowering), or it may be permanent. 
It may be generic, or confined to some particular variety or 
species, or it may be individual. It may be normal or abnormal. 

The practical lesson of this chapter has been that we should 
cultivate our plants so as to avoid the conditions which dis- 
pose them to disease, and that we should rear and cultivate 
these kinds least liable to injury from disease. The considera- 
tion of these points forms the subject of our next chapter. 

' Resin is in itself not antiseptic, and in the fluid condition inside plants 
atfords no barrier to fungus-hyphae of Peridermium plni and Nectria cucurbitula; 
the hardened crust on a wounded surface ser\'es, however, to keep off spores 
from the plant tissues, and prevents the penetration of germ-tubes. 



CHAPTER VI. 
PREVENTIVE AND COMBATIVE MEASURES. 

§ 12. Measures are known for the prevention and cure uf many 
fungoid diseases of plants of agricultural, sylvicultural or horti- 
cultural interest. These have been deduced from the biology of 
the parasite and its relation to its host, and have been used 
practically with more or less success. In a large number of 
eases, however, little advice can be given, because as yet the 
cause of many • diseases is obscure, while for others suitable 
reagents for cure have not been lound. ]\lany of the methods 
known are impracticable from the cost entailed in carrying 
them out. Others, directed against some widespread disease, 
fail from lack of organized co-operation, the eftbrts of a few 
individual cultivators here and there making but little headway 
against the disease, so long as the patches of crop under treat- 
ment are subject to fresh invasion from untreated places. It is 
desirable on this account that the combating of diseases of our 
cultivated plants should be conducted under some kind of state 
supervision. 

The first step towards combating the more destructive diseases 
of plants is the spread of knowledge concerning them, ami the 
remedies available against tliem. In Bavaria and other Oerman 
states this is done for the diseases of sylvicultural importance by 
regular courses of instruction in plant-pathology in the forestry 
schools. In the same way it would also be advisable to give 
similar instruction in agricultural scliools, and also to make it a 
subject for examination. Another important step consists in thi* 
establishment of experimental stations where investigations in 



64 PREVENTIVE AND COMBATIVE MEASURES. 

plant-pathology may be carried out, while at the same time the 
cultivator could have advice with regard to the nature of any 
disease and its treatment. Another system for the supply of 
information is to be found in collections of specimens of plant- 
diseases arranged for easy reference in places accessible to the 
public. 

State supervision over crops under cultivation is also desirable 
with a view to collect and distribute information concerning 
prevalent crop-diseases. The same agency could also arrange 
and, if need be, enforce a general and simultaneous treatment of 
widespread epidemics, where proved methods were known and 
advisable. Such regulations for supervising and combating a 
plant-disease are already universally applied against the Phyl- 
loxera. Similarly in Germany and other countries official 
notice is annually given for extermination of mistletoe ( Viscum 
album) on fruit-trees, and in Prussia the combating of Gnomonia 
erythrostoma is carried out by order of the police authorities. 
The tar-ringing of trees as a preventive against attacks of pine 
moth {Gastropacha ijini), is regularly enforced everywhere in 
forest-countries, and with the best result. In a similar manner, 
in most countries, this and other forest pests are supervised by 
the penal code, and combated with success. 

By arrangements of this kind it is possible to keep certain 
diseases completely in check. Thus, as a result of regular in- 
spection and the timely use of tar-rings, a dangerous outbreak of 
pine moth is well-nigh impossible. Again, the universal steriliza- 
tion of the seed-corn of cereals before sowing has done much to 
exterminate smut-diseases. In the case of the Dodder-disease, 
much can be done for its prevention by the careful purification 
of clover seed. 

We shall consider the methods for combating parasitic fungi 
under the following heads : 

I. Methods for extermination and removal of the parasitic 
fungi alone. 

(1) Killing of fungi attached to seed through sterilization by 
means of hot water or copper steep-mixtures. 

(2) Combating leaf-frequenting fungi by dusting or spraying 
with mixtures containing sulphur or copper. 

(3) Excision and extermination of the sporophores of Polyporeae 
and Agaricini on orchard or warden trees. 



PREVENTIVE AND COMBATIVE MEASURES. 65 

(4) liemoval and destruLtioii of dead parts of plants carrying 
sporocarps or other hibernating stages of any fungus. 

II. Methods for combating fungi by removal of diseased 
plants or plant-organs. 

(1) Eenioval of the parts of a host-plant harbouring fungi. 

(2) Removal of the whole or part of a complementary host 
of a heteroeciou.s fungus, for the purpose of saving the other 
host or hosts. 

III. The avoidance or removal of conditions which favour 
infection. 

(1) Preventive measures against wound infection; antiseptic 
and aseptic wound-treatment. 

(2) Avoidance of localities favourable to disease. 

(3) Avoidance of the massing together of plants of the same 
species and like age ; rotation of crops on the same cultivated 
area. 

(4) Avoidance of neighbourhood of those plants which are 
hosts of the same heteroecious fungus. 

IV. Selection and cultivation of varieties and species of 
cultivated plants least lialjle to the attacks of parasites. 

I. Extermination and removal of the parasitic fungi alone. 

(1) That the seed be clean and free from the spores of 
parasitic fungi, is a most essential condition. The purity of 
seed is investigated in seed-control stations,^ where special 
attention is paid to purity of seeds {e.g. clover, from its 
liability to contain seeds of the parasitic Dodder), and to their 
freedom from spores of smut or other fungi. 

As a preventive against smut, especially those forms due 
to species of Ustilagineae, sterilization of the seed is ad(t]tted,- 
This is chiefly carried out by the use of " steeps," wliicli kill 
the .snnit-spores adherent to the seed. The comi)Ositi()n of the 
steep-li(iuid, and tlie duration of immersion are the points to l»e 
attended to, and for these various recipes are extant. Ifecently 

• .State-iiiiled station.s of this kind are fairly uuinerous in Germany, F'rancf, 
anil oilier continental countrie.s, also in America. It i.s thus somewhat leniaik- 
al)le that in I'.iitain this important work receives no state recognition, hut \s 
left in the hands of more or less experienced analysts, or others. (Kdit.) 

-.Swin^de, W. F. " (Jrain-smuts ami their prevention." Ytarliook of 
U.S. l)>i)t. of A'/riru/Inn, \H'.U. A very useful sununary. (Kdit.) 

E 



66 PREVENTIVE AND COMBATIVE MEASURES. 

it has been pointed out that the different species of Ustilago 
have different powers of resistance, and must be treated 
accordingly. It has been found from experience that when 
trustworthy and tested steeps are in general use in any neigh- 
bourhood, the diseases of crops caused by Ustilagineae gradually 
disappear. This is due to the fact that the smut-fungi frequent 
principally the cultivated cereals, while they are comparatively 
rare on the wild grasses from which, as in the case of " rusts," 
they might make their way to the cultivated forms. 

Sterilization hy Copper Sulphate. 

The " steep " which is in most general use is that first recom- 
mended by Kiihn ^ in 1858. It consists of a i per cent 
solution of copper sulphate prepared as follows : 1 lb. crushed 
commercial sulphate of copper (blue vitriol or bluestone) is 
dissolved in hot water and added to 22 gallons of water. The 
seed is poured into the " steep " and allowed to stand covered 
with the liquid for a night (twelve to sixteen hours). The 
seed is then taken out and allowed to drip. An improvement 
on this method consists in running off the copper sulphate 
liquor and adding milk of lime (prepared by soaking 1 lb. 
good lime in 4 gallons of water), after stirring for about five 
minutes, again run off the liquor and allow the grain to drip. 

If sown by hand the seed may be used in a few hours, if 
by machine it must dry for twenty-four hours. 

Sterilization hy Hot Water. 

Jensen's method for treatment of seed-grain by hot water, 
consists in placing the seed for a certain time in water at a 
temperature which does not injure the grain, but is sufficient to 
kill any adherent smut-spores. This takes place in five minutes 
in water at 132° F. (55° C), but the germinating power of 
the grain will not be injured though it remains a quarter of 
an hour. The immersion is carried out by placing the seed in 
a vessel easily permeable by water ; a bushel basket lined with 
coarse canvas serves very well. A convenient quantity of seed 

'Julius Kiihn, J)h Krankheiten d. Kidturgewdchse, 1858, p. 86. Numerous 
articles on this subject have from time to time appeared in the agricultural 
Journals and Bulletins. 



PREVENTIVE AND COMBATIVE MEASURES. G7 

to handle in such a basket would be a full half-bushel. The 
hot water is best contained in two large boilers, the hrst at a 
moderate temperature, serving to wet the grain somewhat and 
to prevent cooling of the water of the second boiler, which 
must be maintained between 130 F. to 134 F. A lower 
temperature will not ensure death of all spores, a higher will 
injure the grain. The grain is immersed a few minutes in the 
tirst boiler, then placed in the second fo/\fiftcrii minutes, being 
meanwhile frequently shaken to ensure complete sterilization. 
Next the basket and its contents are cooled in cold water and 
the grain spread out to dry.^ 

The important point in the application of these methods is 
their general and simultaneous use throughout a whole district. 

For smut-diseases the removal of diseased plants is at the 
same time a preventive and a combative measure. This is 
not difficult where the plant is large or the disease conspicuous, 
as with the maize-smut ; the diseased plants can then be re- 
moved and burnt before the smut-spores are shed. If the smut 
is not very prevalent it is possible to keep it in check by 
removal of diseased specimens on such crops as maize, barley, 
wheat, and oats. This treatment can also be applied to some 
garden-smuts like that on violets. 

Brefeld recommends as a preventive measure the avoidance 
of the use of fresh farmyard manure. Smut-spores from in- 
fected hay or straw, which finds its way to the manure heap, 
germinate there and multiply yeast-like giving rise to eonidia, 
which, on exhaustion of nutrition, give rise to germ-tubes 
capable of infecting seedling plants. The spores are capable of 
germination even after being eaten with the fodder and passing 
through the digestive canal of animals. In this connection 
Professor Wollny carried out the following experiment at my 
instigation : three fields situated at some distance from each 
other were sown with maize, which I had mixed witli living 
sport^s of Ustilar/o md/filis collected the previous autumn. < >nt' 
field was h-t'l unniaiiuied, the second received old farmyard 
juanure, tiie third fresh. All plants in tlie first plot grew nji 
healthy, two of the .second were di.seased, and «'leven of the 
thinl. The summer being a dry one llic nunibtT of discasccj 

' In the literature iw-siieil from the Uiiite<l States Hxpei iiiuiiliil Statiniis 
other "stoeps" ure given, with results. (Ktlil.) 



68 PltF.VENTIVE AND COMBATIVE MEASURES. 

plants was smaller than usual. The immunity from smut with 
old manure is probably explicable on the assumption that in 
it the kind of nutriment suitable for the smut-conidia is ex- 
hausted, so that any spores, which may sprout, die off. 

It must, however, be here observed that the spores of some 
species of smut-fungi {e.g. Tilletia, the stinking brand of wheat) 
do not germinate directly in manure, but do so in water easily. 
The spores of most smuts are adapted to a long winter rest. 

(2) Other diseases are fought and prevented from spreading 
by the direct extermination of the fungus or its reproductive 
organs while in full activity on the growing host-plant. Tor 
this purpose Fungicides are used, either as powders or solutions 
applied to diseased plants. These reagents are employed with 
most success against epiphytic fungi, where the mycelium is 
fully exposed on the surface of the host. 

The Erysipheae are generally treated in this manner, especially 
the powdery mildew of the vine {Oidiicm Tuckcri or Uncinula 
spiralis). This vine-parasite is combated by dusting from time 
to time with dry powdered sulphur or flowers of sulphur. The 
sulphur may l)e simply shaken from a tin with perforated lid, 
or it may be blown on l)y a sprayer provided with a bellows, 
or dusted on by a sulphur-brush, consisting of a hollow handle 
filled with sulphur which distributes the powder through fine 
perforations in its end to a tassel of fine bristles. In a similar 
manner may be treated the powdery mildews of hop, rose, 
peach, apricot, apples, etc., caused by Erysipheae. 

Fungicides are also used against fungi with endophytic 
mycelia. The Peronosporeae cause injury to quite a large 
number of cultivated plants, and many methods of treatment 
have been employed against them. The mycelium lives inside 
the host-plant, especially in its leaves, and only the conidiophores 
make their appearance externally. Dusting with sulphur or 
spraying with preparations of copper has on this account Little 
effect on the mycelium, but will kill the conidiophores, while 
any conidia or oospores, which may alight on the leaves, will 
Ije prevented from germinating. The most general forms of 
fungicides are various preparations of copper, of which the 
following are some of the more important : ^ 

1 Consirlerable lil)erty has been taken here with the original. The author's 
account has been extended with the assistance of the Journal of Mycology and 



PREVENTIVE AND COMBATIVE MEASURES. 69 

Bordeaux Mixture *>y J5ouillie-l'>urdelaise, a i! to 4 per cent, 
solution of copper sulphate and lime. It is prepared by dis- 
solving 6 lbs. of copper sulpliate in warm water, and placing 
this mixture in a barrel capable of holding about 4-4 gallons ; 
in another vessel slake 4 lbs. of fresh- burnt lime, and make it 
up to a creamy whitewash with water ; strain the lime through 
coarse canvas into the barrel of copper sulphate solution, fill 
up with water, stir thoroughly, and the mixture is ready for 
use. This mixture may be used either more concentrated, or 
somewhat diluted. 

Ammoniacal Solution of Copper Carbonate. This may be 
prt'part'd dirfctly by dissolving 5 oz. uf cupper carbonate in 
enough water to form a thick paste ; dissolve this paste in 
three pints of strong aqua ammonia (or as much as may be 
necessary to effect complete solution) then dilute to 45 gallons. 
If copper carbonate cannot be obtained, make it by mixing {(() 
3 lbs. of copper sulphate in 2 gallons of hot water, (b) '3h lbs. 
wasliing soda in 1 gallon hot water ; mix (a) and (b), add 
water up to 10 gallons, stir up, and allow to settle; pour off 
the clear liquid, till up again witli water and allow to settle ; 
on again pouring off the clear water a greenish sediment of 
copper carbonate remains. This dissolved in as much aqua 
annuonia as necessary, may be kept till required when it is to 
be diliitt'd at tlie rate of 1 pint to 2 gallons of water. 

Eau Celeste. I)is.solve 2 lbs. of copper sulphate in about 
8 gallons of water ; when completely dissolved add 3 pints of 
strong aqua ammonia and dihite to 45 gallons. This may be 
used in a modified form. 

Fungicides like these are used chiefly against attacks of vine 
mildew (Pcnmosjxird viticdJn), ])Otato disease {Phj/toplithoni in- 
J'rstans) and Peronosporeae generally : also for numerous other 
leaf-diseases caused by various fungi. Wliat the results of any 
given exjteriment may be, is as yet difficult to say till more is 
known of the effects of the reagents, the strength of the mix- 
tuie to ]je used, the kind of plant and its stage of development, 
and other factors dependent on climate. The etUcacy of a 
fungicide lies less in its etfects on the fungi actually present 

other American literature, not the least imimrtaiit liiiii^; " r.urdiiiux Mixtnrt- a« 
a Fuiigiciilu," Ity D. V. Fairciiiltl ; V.S. Amir. HulUtin, No. G, ISJM. In tiiin 
fonnectirjn reference may also l)e made to K. <!. Loilemann'.s account of the 
".Spraying of Plants "( .Ma.iMillaii, ISlMi). (K.lit.) 



70 PREVENTIVE AND COMBATIVE MEASURES. 

and causing disease, than on its capacity to kill spores which 
light on the leaf, or to prevent their development to a dangerous 
extent. On this account crops liable to attack should be dusted 
or sprayed in early spring, and at intervals thereafter as long 
as there is any risk of disease. Used in this way, fungicides 
soon repay themselves in increased yield of healthy produce ; 
on the one hand, they hinder the development of the fungus, 
on the other hand, they act like antiseptic wound-treatment in 
preventing infection. What part the copper compounds play 
is as yet not completely established ; liumm ^ considers that 
they are not actually absorbed by the plant, but only give rise 
to some electrical effect. 

The advantage to be gained from the use of fungicides may 
be greatly increased if all diseased plants or portions of them 
be removed before the remedy is applied. Precautions must 
also be taken against reappearance of the disease. In the case 
of infected forcing boxes, frames, or glass-houses, disinfection 
by some of the above fungicides is certainly advisable. Leaves 
on other plant-remains containing resting-spores of the fungus 
should be burnt, and soil containing diseased material should 
be watered with a fungicidal solution which will kill the fungus 
while it does no harm to the leaves or roots of plants. Finally 
a rotation of crops of as long a duration as possible will do 
much to keep epidemic fungoid diseases in check. 

(3) Frequently the -ravages of a parasite can be considerably 
reduced, although not completely stopped, by destroying its 
reproductive organs. Methods of this kind are particularly 
useful in the case of the Polyporeae which inhabit the wood of 
many fruit-trees. The excision of the sporophores must be 
carried out once or twice a year, because the mycelium remains 
alive inside the stems and continually gives off new sporophores 
on the surface. The diseased tree lives on and produces fruit 
for many years, maybe till the wood of its stem becomes so 
much decayed that death ensues. Fungi of this family are 
even more destructive on those trees which are cultivated not 
for their fruit alone but also for timber, e.g. olive, sweet chest- 
nut, and hazel. 

(4) By the removal and destruction of dead plants or portions 
of plants containing reproductive or hibernating organs of para- 

^ C. Riinim, Berichte d. deutAch. hotan. Ges. 189.3. 



PREVENTIVE AND COMBATIVE MEASURES. 71 

sites, much may be done to shorten the existence of a disease, 
and to prevent its reappearance in the following spring. 

Fungi which reach maturity on fallen leaves are easily com- 
bated in this way. Hartig gives a striking example of the 
success of this measure. In the English Garden, a large park 
in ^Munich, the leaves are carefully removed at frequent intervals 
as they fall, and utilized as stable-bedding ; here Rhytisma 
acerinum, the black spot of the sycamore leaf, is hardly known, 
whereas in the park at Xymphenburg, and in other places 
round ^lunich, where the leaves are allowed to remain lying, 
the leaf-spot is very common. Rhytisma salieinum can be 
treated in the same way in osier- nurseries. In plum orchards 
Polystiyma ruhrum may be held completely in check by removal 
of fallen leaves. So also the numerous mildews (Erysipheae) 
of our cultivated plants. Cherry leaves killed by Cruonwnm 
crythrostoma remain hanging on the trees, but the disease has 
almost disappeared since the practice of removing and destroying 
these was introduced in gardens, like those of the Altenland, 
once completely devastated by this parasite. 

The progress of the disease caused by Nedria cinnaharina is 
reduced if the branches which die daring the summer be at 
once removed and burnt before the red fructifying patches 
appear. It would also be advisable to ])urn in the autumn 
other dry laushwood, since it frequently contains Ncctria and 
other wound-fungi, and if left over winter only serves as a 
nursery and source of infection for all neighbouring trees. In 
a similar way should be treated branches infected with sporo- 
carps of Cucurhitario lahurni and such-like fungi. 

Immediate removal, burning' or burvino; of yoim^ trees 
attacked by I'Jiyfi>i>htliora omnivora is of advantage in prevent- 
ing the distribution of the fungus by conidia and swarm-spores 
during summer, its hiix'rnation in dead tissues, and its coiilinut'd 
distribuiinii in the tnll()\viu;4 spring. The hibernating oospores 
of many otber lower fungi may be similarly g(»t rid of by 
destruction of tlu' plant-remains inhabited by them. 

II. Removal and destruction of diseased plants or portions of these. 

(1) Tlie ri-niDval ^^[ synibiutic organs comes hcic particularly 
into notice. AnioUL'si these arc llic " witclu's' brooms " whicb 



72 PREVENTIVE AND COMBATIVE MEASURES. 

live for years on their host deriving nutriment from them ; 
they also are detrimental to fruit trees because they bear 
neither flower or fruit, and on some timber trees they so 
deform the stems as to considerably reduce their value. The 
witches' brooms of the cherry or the plum grow into large 
infertile bushes of striking appearance, so that they may be 
easily detected and removed in autumn or spring ; those on 
hornbeam, birch, and alder are of less practical importance, 
but should be cut off wherever accessible. 

Great damage is caused by the witches' broom (Accidimn 
clatinum) of the silver fir in producing canker spots which 
may in some cases attain gigantic dimensions and thereby 
much reduce the value of the timber, or maybe render it quite 
valueless. The cankered spots are, in addition, frequently attacked 
by wound-parasites, whereby the stem is weakened and breaks 
over at the canker, causing breaches in high forest, which can- 
not be refilled. The witches' brooms should therefore, as far as 
accessible, be cut off while still young, and all cankered trees 
should be removed at the first thinning. 

The removal of twigs of plum bearing the so-called '•' pocket- 
plums " or " fools " is also to be recommended, because the my- 
celium of the fungi causing these hibernates in them. Eose-twigs 
affected by rose-mildew {Sphaerotheca pannosa) should also be cut 
away as soon as possible, before many plants have fallen victims. 
Portions thus removed are both worthless and dangerous, hence 
should l)e destroyed. So also all trees rotted by fungi should 
be removed from their healthy neighbours, and, if possible, 
burnt or buried, or otherwise rendered harmless. 

This forms a convenient place to consider generally the 
wood-destroying- wound-parasites of our timber-producing 
plants. 

The wood-destroying wound-parasites belong chiefly to the 
families of the Polyporeae and Agaricini, and each possesses a 
mode of life and method of destroying its host, so similar to 
that of its relatives, that it is quite impossible to consider them 
separately in a practical way. They are enemies of our fruit 
orchards, our parks, and our forests, and the means to be em- 
ployed against them varies in the hands of the fruit-grower, the 
gardener, or the forester. 

Every fruit-tree, whether grown in a garden, an orchard, or 



PREVENTIVK AND COMBATIVE MEASURES. 73 

on a roadside as in some countries, is an object of .such value 
that, if need be, costly methods can be employed on its behalf. 
Its branches must be kept free of all intruders like the 
mistletoe, witches' brooms, mosses and lichens, and above all, 
from the sporophores which indiciite the presence of a wood- 
destroying fungus. This is all the more easy because the trees 
are frequently closely examined for pruning, for crop, or for 
insect attacks. The sporophores of fungi on stems and branches 
should, as already indicated, be early and carefully cut out, the 
wound scraped and tarred over.^ In this way tlie fungus will 
be deprived of its sporophores and the safety of other trees 
ensured, although it must be remembered that the mycelium 
still continues to destroy the wood and probably to produce 
new sporophores. If the sporophores appear on weak branches, 
these would best be completely cut oft" and the cut end tarred 
over. Trees although diseased and requiring annually to have 
sporophores cut out should still be spared, as they often continue 
to live and yield heavily for years. Amongst the sporophores 
which appear frequently on fruit-trees are those of Polyponis 
igninrius, P. fidvus, P. his2ndus, P. sv.lj)hurens, P. sqtiamosus, 
P. spumeus, Hychmvi Schicdcrmayri, and others to be more closely 
considered in the special part of this work. 

Particular attention of this kind is of course more difticult 
for the park-gardener, because his trees are higher and stand 
closer together. The trees are, however, of less value individually 
than fruit-trees. It is advisable, as far as possible, to keep the 
trees clean, to tar all wounds and to remove poorly developed 
branches and stems. 

To the forester in high forest all this is, however, a matter 
of difticulty. The trees are higli, the forest large, ami the 
individual trees of a value which does not allow of cosily 
labour being expended on them. Yet tliere is one I'orest 
operation in wliich a plantation may at small cost be easily 
cleared «jf diseased stems. This is the repeateil process of 
thinning, during which all diseased and backward trees should 
l)e felled. In forests of high value wiih liiuli-])rieed timber 
and near towns (jr centres (jf industry, this eleaning out is, of 
course, easy, but in remote forests with a small working stall", 

' Tlic Hporopliort'H ciiiiiiiil 1)1' icMiovcil ton young ; tliu mihiihIs prixliu-i-il hIiuiiIiI 
Ije trciitetl with tar ; see .'^eL-tinii in., p. 77. 



74 PREVENTIVE AND COMBATIVE MEASURES. 

deficient modes of conveyance, and a small demand for the 
thinned-out material, this may appear impracticable. I shall 
give one example how the number of " fungus-sponges " (as 
the sporophores are called) decrease with enclosure and intro- 
duction of proper forest-management.^ Bischoffsreut is a forest 
in Bavaria, near the Bohemian frontier, consisting of mixed 
spruce and fir up to four hundred years, and beech up to 
two hundred. Forty years ago the sporophores of Polyporus 
fomentarms, the tinder-fungus, were so numerous and large that 
for their collection for manufacture of caps, gloves, tinder, etc., 
a sum of one hundred gulden (£8 10s. Od.) was paid annually 
as rental. Ten years ago the same brought in a revenue of 
twelve shillings ; to-day it is free. In course of time the 
diseased stems have been gradually felled and less wood has 
been allowed to remain lying in the forest to decay ; as a 
result the wood-destroying fungi have now but little foothold. 
A mixed damp virgin forest is especially favourable for the life 
and distribution of fungi of this kind.^ All fallen wood remains 
lying, while injuries from storm afford easy spots for infection. 
In Bischoffsreut eighteen per cent, of the felled heavy wood 
was at one time useless and rotten. 

(2) It is often possible to avert diseases of valuable cultivated 
plants caused by heteroecious fungi, by keeping the supplemen- 
tary host at a distance, or, if the disease has already broken 
out, to remove it altogether, with the view of keeping the 
more useful host free from the dreaded disease. 

The best example of this is presented by the heteroecious 
rust-fungus Gymnosporangium sahinae. One host frequents 
Juniperus sabina (savin), the other damages pear-trees, causing, 
in the case of a severe attack, considerable loss. It would thus 
be easy to exterminate pear-rust by removing the not very 
decorative savin-bush. Particularly in nurseries, it would be 
well to avoid placing pear-trees near the savin, an arrangement 
very suitable for cultivating the Gpmiosjjorangium. 

As another example we may take Ifelampsora tremulae 
frequenting the aspen, the supplementary host of {a) Caeoma 
pinitorqvum (the pine twister), and (h) Caeoma laricis (larch 

'v. Tubeuf, " Mittheilung lib. einige Feinde d. Waldes." Alleg. Forst.-XL. 
Jatjdzeitunt/, 1S87. 

*v. Tubeuf, " Vegetationsbilder, aus d. boehniischen Urwalde." Oesterreich, 
Forsizeitunij, 1890, p. 108 ; with six figures. 



PREVENTIVE AND COMBATIVE MEASURES. O 

needle-rust). The exclusion of the aspen from the neighbour- 
hood of pine plantations is advisable as a means of limiting 
the pine-disease, and is now being recommended in forestry. 

Still another example is ruccinia graminis the rust of 
wheat and its Accidinm on the barberry. This is, in all 
probability, able to reproduce itself by means of uredospores on 
wild grasses, and to retain its position without the barberry, yet 
the latter doubtless tends to distribute the disease, and its 
removal minimises the risks of attack. 

An investigation of the heteroecious rust-fungi will easily 
furnish many examples of the same kind, and lead to the con- 
clusion that Euphorbia cyparissias, for example, should be 
exterminated near fields of peas or other Leguminosae because 
of Uromi/ccs pisi, and U. striatus. 



III. Avoidance or removal of conditions which favour infection. 

Various examples of this have already been given when 
the conditions disposing plants to disease were uiuler considera- 
tion in our last chapter. 

(1) The most important measures of this class are those 
directed against infection through wounds. This mav be 
attained by avoiding any unnecessary wounding of woody plants, 
and the immediate treatment of any wounds rendered necessary 
in pruning or other operations. 

"When the stems of woody plants are injured, the first step 
towards healing the wound proceeds from the tree itself. 
Conifers containing resin have in it a very ready agent im- 
mediately available ; the resin escapes fr<jm its ducts and soon 
hardens into a crust on exposure to air. In the case of non- 
resinous conifers and of liroad-leavud trees, the first steps 
towards healing are less obvious, but it lias been found that a 
healing tissue immediately begins to form on wounded surfaces.^ 
It consists of a parenchyma, the formation of which is induced 
apparently by atmospheric air penetrating into the wood, ami 

'v. TuKciif, " Ucljer nonnale u. patliogene Kernltililimj; il. nnl/plliiii/tii 
u. d. l'>(liiiii<lluiig V. Wuiiiliii iliTstlhen, Ztilxchri/t f. Foist. -u. Jci'i'/.-irtmii, 1889. 
Contuins IJihliuj^riipliy (.f iillictl jiuper.s. 

R. Hiirtig, DimuHtM of Trtex, Knyliuli Kdition, 1H!(4. 

(!mim isdorfer, .9iV-.HH_</s/»'r. il. k: Akail. d. WiMsmschitt'l. \'i«iiim, Issl. 

|{<«lirii, " L'llier ilii- Fiiiirtioii d. veget. (!ef:iHse," liolmt. X'ititini, l>s7'.'- 



76 PREVENTIVE AND COMBATIVE MEASURES. 

its object probably is to restore the same condition of gaseous 
pressure inside the tree as existed previous to the injury. A 
number of woody plants, for example, Robinia and Qucrcus, 
which normally form tyloses in their heart-wood or sap-wood, 
do the same on wounded surfaces, and thereby stop up all 
the cut vessels.^ 

The formation of tyloses is due to sac-like ingrowths into the 
vessels from adjoining parenchyma, and can only take place 
where rapid growth of the closing membrane of pits or the thin 
portions of the wall of annular or spiral vessels occurs. Tyloses- 
formation takes place in normal heart-wood, and also in the 
sap-wood of many kinds of trees, except in the very youngest 
water-conducting year-rings. It also occurs in leaf-scars at the 
the time of normal defoliation.^ Species of trees in which 
tyloses are not normally produced in the heart-wood, but in 
which the vessels of that region become filled with resinous 
secretions, use these substances as healing agents in the case of 
leaf-fall or wounds to the wood. For these reasons it is quite 
correct to designate these preliminary steps towards wound- 
closure as a pathogenic formation of duramen, and the tissue 
derived from the process as wound-duramen. Similarly a corky 
tissue — wound-cork — may be formed in consequence of wounds 
to the bark or as an accompaniment of certain diseases. I 
have repeatedly observed that the normal duramen is preyed on 
for nutriment by many wound-parasites, and also that this 
wound-duramen is not sufficient to keep out germinating spores 
-of the wound-parasites. It cannot therefore be designated a 
protective wood, nor are the artificial methods of closing w^ounds 
so superfluous as some would have us believe.^ 

Frank says : " The use of all such artificial means of healing wounds 
is thus only necessary in serious cases, in which, in consequence of delay 
in the healing-process, decay would be inevitable without some septate 
agent. Smaller wounds, and particularly cut surfaces of twigs or thinner 
branches, are, by the natural formation of protective wood accompanying 
■every wound of the wood, sufficiently protected for the few years the 

' Molisoh, " Zur Kenntniss d. Thvllen," Akad. d. IVissenschaft, Vienna, 1888; 
Wider, Biolog. Centralblatt, 1893. 

-Staby, " Ueber Verschhxss d. Blattnarben nach Abfall d. Blatter," Flora, 
1886. 

■' Prael, Primjahehn n Jahrbuch, 1888. 
Temnie, Laiidwirthscha/tl. Jahrbuch, 1885. 
Frank, Die Krunlchtiten d. Pjlanr.en, 1894, p. 153. 



PREVENTIVE AND COMBATIVE MEASURES. 77 

wound must remain open till completion of occlusion.' If we followed 
this view, then numerous wounds would be left freely open as entrances 
for wound-parasites, and serious loss would result. It is just the numerous 
smaller wounds {e.g. those produced by hail), which are the principal i)laces 
of infection for species of Xectria, Cucurbitaria, Hymenomycetes^ etc., in 
fact, they form very convenient places whence a tree may be easily infected 
artificially. 

The following points in regard to treatment of branches may 
be conveniently summarized here. Trees in closed plantations 
are naturally stripped of their branches by these dying in con- 
sequence of deficient illumination ; they then break oft', and 
the short stumps are soon occluded or grown over. During 
this process there is always a risk of infection by fungi, and 
" snag-pruning " ^ is employed to shorten the period of occlusion 
as much as possible. This at the same time prevents the in- 
clusion of long branch-stumps in the timber, and reduces the 
number of knots in sawn boards. Such dead snags or stumps 
are deficient in nutritive materials and very dry, so that they 
are less suited for the entrance of wound-fungi than wounds on 
the living branch. 

The usual process of forest-pruning is necessary to produce 
clean boles, to increase the illumination for undergrowth, or 
to utilize the branches so removed. In the operation., all 
branches should be cut off" close to the shaft, no snags should 
be left, nor nmst injury be inflicted on neighljouring bark. 
The operation is best carried out in autumn or winter when 
the bark is most adherent to the wood, occlusion tlien liegins 
with the renewal of vegetative activity in spring and is well 
advanced by the time the greatest dispersal of fungus-spores takes ^ 
place. Infection by fungi will, however, be rendered quite 
impossible if wounds are immediately painted over with tar, or, 
in the case of smaller wounds on garden stock, with tree-wa.x ; 
these reagents, if applied in winter, will easily penetrate into the 
wood, and even replace the formation of protective wound-wood. 
Hartig says on this subject : ^ " tarring produces satisfactory 
results only when pruning has been done in late autumn or 
in winter, because it is only then that the tar is absorbed liy 
the surface of the wound. it would apjicar that the absorption 
of tar is du(' partly to tlif diiiiiuishcd ainnunt ol' water in tb"' 

' TioL-kenaHtung. -Hartig, JJiiia.it i of Tikx. Knglisli IMit. |(. -.'iS ,");i. 



78 PRf:VENTIVE AND COMBATIVE MEASURES. 

wood during autuiiin, and partly to the consequent negative 
pressure of air in the tree. When pruning is undertaken in 
spring or summer the tar altogether fails to enter the wood, 
and the thin superficial layer does not prevent the cut surface 
from drying later and forming fissures into which water and 
fungi may enter." From what has been said it follows that 
dicotyledonous trees may be best pruned in the months of 
October, November, and December — perhaps also in January 
and February, — and that a good coat of coal-tar should be at 
once applied to the wounds. 

Conifers should also be pruned in autumn and winter, for 
although the wounds resulting from removal of small branches 
with no heart-wood are soon protected by an excretion of resin, 
yet thicker branches with heart-wood, which secretes no resin, 
must be tarred over. Similar precautions are advisable to 
protect the stools of trees felled in order to produce coppice. . 

Wounds are produced on fruit-trees by removal of branches, by 
pruning and grafting, and again during the fruit-harvest. Hail 
and wind are frequent sources of wounding. Gnawing of the 
bark by animals, such as mice and other rodents, may also occur. 

Eed deer, by peeling off the bark, are a source of great 
damage in the forest. In this way spruce plantations may be 
so peeled, and in consequence so subject to red-rot that they 
have to be prematurely felled. The trees which suffer most 
are those like spruce, silver fir, Weymouth pine, and Douglas 
fir, which remain for a considerable time smooth-barked, whereas 
species with a rough bark are comparatively safe ; the latter 
can also cover up any wounded surface by means of an excretion 
of resin. Conifers suffer most from peeling, but the broad- 
leaved trees are not quite exempt. At certain seasons the deer 
rub the fur off the young antlers or knock off' the old ; for 
this purpose they generally choose younger plants, which, in 
consequence of the injury, frequently dry up. Injury by deer 
is more serious in summer than in winter, because with the 
increased temperature and moisture the spores are able to 
convey infection quickly and easily. 

Injuries similar to peeling by deer are produced in gathering 
resin, and in the process of " testing " the timber of conifers. 
Both practices are, however, prohibited in well-managed forestry, 
and occur only as misdemeanours. Piesin-collecting of whatever 



PREVENTIVE AND COMBATIVE MEASURES. 79 

kind, whether from spruce, larch, phie or the silver fir, necessi- 
tates removal of the bark, and probably cutting into the wood 
itself The exuded resin and naked wood dry up in course of 
time and crack, thereby allowing the entrance of fungus-spores, 
which germinate in the fissures of the wood and lead to its 
destruction. 

The forests of spruce and fir in ]>avaria furnish valuable 
wood suitable for the manufacture of violins and other musical 
instruments. Till recently the practice was first to split a test- 
piece from the standing tree to ascertain the cleavage of the 
stem. If the test did not split true, the tree was left standing 
and wounded ; such stems naturally were soon attacked by fungi 
(Polyporeae and Agaricini) and succumbed to some storm. 

The beech is frequently injured in a somewhat similar manner 
by the woodmen, who hew out large pieces of the stem to obtain 
material for wedges from the very tough occlusion-tissue which 
is afterwards formed. Stems so damaged soon fall a prey to 
Polyporus fomentarius. Wounds to the wood are also frequently 
produced during the felling of neighbouring trees, or as a result 
of storms, or by the action of woodpeckers, ants, and other 
enemies. In short, wounds are so common that the necessity 
of practical remedial measures for closing them as entrances 
for destructive parasites, must be at once evident. 

(2) Localities should be avoided which are known to pre- 
dispose certain plants to disease. Just as one avoids cultivating 
tender plants in cold situations, or planting our less hardy 
trees in places known to be liable to frost, so ought we to 
avoid the cultivation of plants in localities which will render 
them more than usually liable to infection by fungi. Thus the 
formation of spruce-nurseries at considerable elevations has had 
to be abandoned, because it was observed that they were there 
liable to complete destruction by Herpotrichia nigra. For 
similar reasons the hole-planting of spruce in elevated situations 
must be avoided. In moist localities nurseries of Douglas fir 
and other trees are in danger of attack from Botri/ti.-<\ while 
close glass-houses and h()t-l>eds arc lirt'cding-places for many 
parasites which would at onci- die away with good vtiitilatioii. 

(3) The neighbouriiood of plants which are suiipleiucnial 
hosts of the .same heteroecious fungus should also be avoided. 
(See also p. 74.) 



80 PREVENTIVE AND COMBATIVE MEASURES. 

(4) The massing of numbers of the same species of plant 
together is dangerous, because it presents a favourable oppor- 
tunity for tlie rapid spread of epidemic diseases. On this 
account the smaller fields of small holdings tend to prevent 
any epidemic from assuming serious proportions. Still better 
is a system where, as in Northern Italy, a few rows of vines 
alternate with narrow strips of Indian corn with gourds or 
melons on the ground below, and strips of grass or millet 
intervene here and there. 

Wherever similar plants must be cultivated in close neigh- 
bourhood over extensive areas, as in vine cultivation, any 
epidemic, which may obtain a hold, soon produces disastrous 
effects. Our cultivated forest plants, when occupying extensive 
areas, are particularly open to attacks of certain fungus-diseases. 
Thus Pines from Hysterium pinastri, Caeoma innitorciuum, and 
Peridermium pini ; pole-forests of pure spruce from Hysterhi'm 
meter osjjorum, all plantations of conifers from Trametes racli- 
ciperda and Agariciis melleus, the latter especially if preceded 
by beech forest, the stools and dead roots of which offer the 
Agaricus an opportunity for easy and abundant development. 

The prevention of many epidemic diseases is one of the 
advantages claimed by Gayer ^ in favour of natural regeneration 
and mixed plantations. On exposed areas the p^revailing strong 
winds facilitate distribution of many fungus-spores, while, at 
the same time, they introduce the supplemental hosts of 
of heteroecious fungi {e.g. aspen, ragwort, cowberry, etc.), which 
would be excluded from a closed permanent mixed forest natur- 
ally regenerated. Of course, we do not maintain that, under 
these conditions, diseases are entirely absent, because it is just 
on naturally-sown beech seedlings in closed forests that Pliytopli- 
thora finds a habitat. Similarly Tricliosphacria on silver fir, 
and other parasites, are in closed forest provided with that 
degree of atmospheric moisture which favours them. In fact, 
several parasitic fungi exhibit adaptations to such conditions. 
Diseases, speaking broadly, are less dangerous in mixed forest ; 
they never attain the same distribution, and they are more 
easily restricted where trees of different dispositions are grown 
together. Thus, the forests of Bavaria consist, in the lower 
elevations, of mixed beech, silver fir, and spruce ; higher up 
^ Gayer, Der ]ValdJ>au. 



I'RKVENTIVK AND COMP.ATIVK MEASURES. 81 

the beech is omitted, and in the more elevated parts spruce 
alone is planted. The fir alone is attacked by PJunna ahietina 
Aecidiuni elatinnm, Lophodcrmium nerviseqnium, Trichosphaena 
jKirasitica ; the spruce, on the other hand, has to itself 
Lophodcrmium ma.crosporum, Chvy^onnjjM abldvi, Hcrpotridiia 
nigra, while both are subject in youth to Pestalozzia Hartif/ii, 
and later to several wood-destroyin^f funi,n. 

The storing together of crops like apples, potatoes, oniuns, 
turnips, etc., should be carefully carried out. They should be 
handled as little as possible, and decaying individuals should be 
sought out, and destroyed when possil)le, to save the remainder. 



IV. Selection of hardy varieties. 

An important method for the protection nf [)lants tiuin disease, 
both from the preventive and remedial side, consists in the 
selection and cultivation of varieties and species of plants able 
to resist the attacks of parasitic fungi. 

It has already been mentioned that different varieties and 
species show different powers of resistance against enemies. As 
a further example, we have numerous American grape-vines 
which are not attacked by downy mildew (Flasmojmra viticola), 
that dangerous enemy of the European vine of cultivation 
(VifAs rinifcra). Some American vines (c;/. J'ilis riparia) 
are proof against the phylloxera, the root-louse which attacks 
the roots of European vines and devastates the vineyards of 
the wine-producing countries ; while, on the other hand, other 
American vines are no more resistant than the European. In 
fact, it was the importation of those vines into Eur(»pe for 
experimental culti\'ation which Ijrought us both phylloxera and 
the dowuN' mildew. The culti\ati(»n of such disease-proof 
species would ensuie us immunity from the piiylloxera, if it 
were not tliat the wine from these vines has neither tiie (jualitv 
nor the llavour possessed by the European. ( )ii tin's account 
the grafting of European vim-s on American stocks lias lieen 
introduced, whereby the roots remain nnattacked l)y the 
jjhyjioxera, and ilie t:raj)es are of the appioNcd standaid. \'crv 
g((od results liave also been obtainetj from e.\|ierimenis in 
hybridizatiitn f)f American and l'!uro))ean vines with the obiect 
of obtaining roots from the American iianiit, and L;rapes fiom 

!■ 



82 PREVENTIVE AND COMBATIVE MEASURES. 

the European. The long and patient experiments of ^Millardet ^ 
are the most conspicuous amongst many which, by means of 
grafting and hybridization, have aimed at obtaining disease-proof 
vines. Millardet, out of numerous hybrids raised by him, has 
succeeded at last in obtaining vines with roots proof against 
phylloxera, leaves resistant to attacks of downy mildew, and 
grapes which impart the esteemed flavour to the various old 
and well-known European wines. From these many ruined 
vineyards of southern France have been already re-stocked, and 
promise well. 

The results obtained from Eriksson's investigations on cereal- 
rusts are also worthy of notice.^ This investigator, after carrying 
on cultivations for a number of years, has found that there are 
varieties of wheat able to resist the more frequent forms of 
rust, and in no way endangered by them. By a similar method 
of investigation, varieties suitable for cultivation in the rust- 
infested districts of Australia have also been obtained. 

^ Millardet, " Notes sur les vignes americaines." Ser. iii. Mem da la soc. c/es- 
.sciences de Bordeaux, 1891; Journ. (V a<jricidture pratique, 1892; Compt. rend., 
1894; Zeitsrhrift f. PJlanzenkrankJieiten, 1894, p. 47, and 1895, p. 116. 

Esser, "Die Bekatnpfung parasit. Pflanzenlirankheiten," Samml. wisstm^ch. 
Vortrdf/e; by Virchow n. Wattenbach, 1892. With Bibliography. 

^Eriksson. Zdtschrift f. Pflanzenkrankheiten, 1895, p. SO. 



CllAlTER VII. 
ECONOMIC LMPOIJTAXCE OF DISEASES OF PLANTS. 

.^ lo. The ecouoiuic iiuportance of any plant-disease depends on 
its distribution, its intensity, and the value of the plants attacked. 
Of most consequence are those epidemic diseases of fungoid origin, 
which cause rapid death of their host, and spread with great 
rapidity over wide areas. Such, tln-ough repeated attacks, 
may render the cultivation of certain plants impossible 
in a locality. Almost equal damage may result froiu those 
parasites, which, although they do not kill their ho.st, yet 
destroy or prevent the development of that part for which we 
grow the plant. Among.st these are species which inhal)it 
flowers or fruits, the wood-destroying fungi of forest-trees, 
and forms inimical to the foli;;.',fe, roots, or tubers of ])lants 
of economic value. 

As examples of parasitic fungi which bring about ra])id doaih 
of their liost, are the originators of many diseases of young 
plants. PhijtoplithoTd vinnivora may during a few days of dau)]» 
weather completely kill out not only Iiealthy beds of seedling 
beech or conifers in the nursery, but even the young plants 
by which a forest is being naturally regenerated. J^rsta/iczin 
Hartigii, a few years ago in the beech-forests in some districts 
of Bavaria, exterminated three-fourths of tln^ nalurally-sown 
plants from one to four years old. }[< rinttrichin uli/rd is 
capable of completely destroying the young spruce jilantalions. 
HO important for the afforestration of ])iire slopes in mountainous 
districts, and it may attack with such violcnct' nurscrirs 
established at <'reat cost and labour that ilu'\' have lo be 



«4 ECONOMIC IMPORTANCE OF DISEASES OF PLANTS. 

abandoned. Whole, gardens of roses have been devastated by 
PcrunosjuH-a sparsa, and inirseries of conifers have been exter- 
minated by Ht/sterium j^inastri, or A/jaricvs mrlleus. 

Amongst the fungi, which attack the organs of older plants 
and cause serious losses to cultivators, are the following : the 
well -known potato disease caused by PliytopMliora infestan>i\ 
the vine diseases arising from Uncinvla sjnralis, Plasmojjara 
viticoln, and Dcviatoj^hora necatrix ; many diseases of conifers 
and other trees. As destroyers of the fruit alone may be 
mentioned the smut-fungi of the cereal crops. 

Other cases of injurious diseases, of more or less practical 
import, will be described in the special part of this book; at 
present we shall only select a few estimates of the loss result- 
ing from them. 

In the forest of Bischoffsreut in Bavaria — a magnificent one, 
containing spruce, fir, and beech — eighteen per cent, of the 
felled timber consisted of wood rendered useless by decay ; 
while fifty years ago the utilizing of the so-called fungus-sponges 
of J\)hji)(irus foincntarms in the same forest for manufacturing 
purposes and for tinder, was let for a small sum (see p. 74). 

Higher figures are, however, reached when we calculate the 
injuries on vines or cereal crops. Pierce,^ in 1892, furnished 
estimates putting the loss resulting from the Anaheim vine- 
disease in (3alifornia at ten millon dollars. The area of infected 
land was about 25,000 acres, in great part with an original 
value of 300 to 500 dollars per acre, 1)ut so depreciated in 
the course of five years that it became worth not more thar> 
75 to 200 dollars. 

In the Zeitschrift fur Pflanzenkranl'luitcn 1893, the inter- 
national phytopathological commission gave, from estimates 
mates furnished by the Prussian statistics-bureau, a review of 
the losses in Prussia from grain-rust. Amongst other esti- 
mates we find that in 1891 the wheat harvest of Prussia 
reached a total of 10,574,168 doppelcentner,^ which at 22 
marks per d.c. = £11,459,690 sterling. Of this 3,316,059 d.c. or 
£3,593,758 was depreciated by rust. The rye harvest was 
30,505,068 d.c. at 22 marks, of which 8,208,913 d.c. 
or £8,896,364 was depreciated by rust. Oats reached 

1 The California Vine-Disease. U.S. Dept. of Agriculture, Bull. 2„ 1892, p. 15. 
- Doppelcentner = 100 kilogramme. 



EfONO.MKJ 1MP(»KTAN(JE OF DISEASES Of I'LANTS. ^5 

32, 165,473 d.c. at 16 marks, of which 10,32o,124 d.c. 
or £8,138,023 falls to be deducted on account of rust. 
Thus on tlie crops wheat, rye, and oats, the loss reached the 
sum of £20,628,147 sterling, or almost a third of the total 
v^alue of the crops. The year 1891 was a very unfavourable 
one, but even taking the estimate at the half of the above 
sum we have a yearly loss by rust amounting to £10.000,000 
sterling. 

In Australia the loss in the wheat harvest of 1890-91, on 
account of rust, has been estimated at £2,500,000 sterling. 

Consideration of the loss of sums of money like these, which 
might be considerably reduced if energetic and universal measures 
were employed against fungoid plant-diseases, will serve to em- 
phasize the importance of remedial measures. It nmst also be 
borne in mind that the use of diseased t'liildfr,^ especially liav, 
grass or grain, infested Ijy rust or smut-fungi, is productive of 
serious results to the various animals of the farm ; while the 
use of meal ur Hour contaminated with smuts, stinking-sunits, or 
ergot is dangerous for mankind. 

' Fr.iliner, Lehrhio-fi ,/. Toxikolonk f. Thinrarztt, 1890. 



CHAPTER VII I 

SYMBIOSIS. 
!^ U. MUTUALISM. 

^Iiituiilisni, or Symbiosis in the stricter sense,^ has been 
distinguished as a special case of parasitism. This condition 
occurs when a parasite and its host mutually work for 
the l)enefit of one another, each contributing to the other's 
nourishment. The lichens furnish the most conspicuous example. 
Here fungus-hyphae unite with algal cells, the algae furnishing 
the fungi with assimilated organic nutriment, the fungi pro- 
viding water and dissolved salts for the algae. 

While it is by no means uncommon to find two organisms 
taking a mutual advantage of each other, yet mutualism in its 
strictest sense is a rare phenomenon. For it generally hapi)ens, 
and is indeed to be expected, that one or both symbiotic 
organisms modify in some degree their mode of life to suit the 
altered conditions necessary for their mutual support. Thu.s 
amongst the lichens, as a result of the union of fungus and 
alga, a living organism originates, which in form, necessities, 
and mode of life is quite nnv, and differs completely from 
eitlier of its components. In the lichen-community, the fungus 
alone reproduces itself; yet the alga occurs as a free organism 
in nature, while the fungus can only be reared in artificial 
culture. This combination might perhaps be compared w4th 
that of oxygen and hydrogen to form water, also to a certain 
extent with the union of the sexual cells to produce a new 

' Tlie term Sj'iiibiosis was applied l)y De Baiy, (who introduced it), by Frank 
and others, to denote those cases where a cohabitation or partnership was 
ol>.served to take place between two different organisms. (Frank, LehrJmch d. 
Bolnvik, 1S92). " Mutualism" was first used by Van Beneden. 



MUTUALISM. 87 

individual. These, and other example.s, will .serve to illu.strate 
how we have in the lichen an organism w'ith peculiarities of 
structure and of life, widely differing from those of either an 
alga or a fungus. This unification of two living beings int<i an 
individual whole, I have designated " rivUvidnation." ^ 

In the case of the lichen-symbiosis, the chlorophyllous part 
consists of minute algal cells, completely enclo.sed in a tis.'^ue 
of fungus-hyphae, and the lichen lives as a perfectly isolatccl 
and independent plant. The case is, however, different wlit-ic 
the fungus enters into parasitic relationshii» with the green 
cells of a large plant. Union may then take place, .so that tlu- 
fungns lives on, or in.side its host, and removed from contact wiib 
any other substratum. The fungus is, however, not in a position 
to convey any nourishment to its host, and in fact is absolutely 
dependent on it for the organic substance and water necessary 
for growth. "Where, however, the relationship is such that the 
parasitic fungus is still in contact with some other substratum, 
then it may be assumed that, in spite of its para.sitisni, it 
takes up nutriment from this source, and shares it with its 
host. This, as has already been pointed out, is the state of 
things in the lichens, where the fungus completely envelopes 
the snuill i.solated algae, and nnist, as a condition of the growth 
of the lichen, remain in direct contact with the substratum : 
the fungus is believed to take from the substratum water and 
inorganic food-material with which it su])plies the algae, while 
it receives in return plastic organic substance to l>e used in 
its own growtli. Of course cases do occur amongst the lichens, 
where, in moist places, the alga is not dei)endent on the funuus, 
or, on the other hand, where the fungus can itstdf take u]> 
organic substance from its substratum. 

Another example of the case is the union of i'ungi with 
non-chlorophyllous ])lants which inhabit humus (e.g. MoiKitrnjni^. 
Here the fungus takes ujt oiganic nourishment fntm the 
substratum and supjtlies it to the higher plant, which, in 
con.sequence of its lack of chlorophyll, is directly dept'udcnt on 
the plastic organized substance from the snil, supplied ihrou-b 
the agency of the fungus. The latter, iiowever, receives nothing 
in return ; it re<piires nothing, since its substratum offers it 
the most f'avouiable conditions for nutriti<»n. This form of 

' liiili\ iiliKili.srriiiM. 



88 SYMBIOSIS. 

symbiu.sis, in which the fungus becomes the nurse or feeder, I 
distinguish as Nutricism. Between the case just cited and 
that in whicli the fungus is a pronounced root-parasite on 
green plants, there exists every possible intermediate stage. 

JJelbre nutricism is considered in detail it would be well to 
exempliiy briefly from the ranks of plant-parasites, that pheno- 
menon of individuation so sharply defined in the lichens. 
A large number of parasitic fungi cause local cell-enlargement and 
cell-increase, with the frequent result that an attacked plant- 
organ becomes very nmch enlarged and its form much changed. 
Gne speaks in such cases of hypertrophy and hypertrophied 
organs. It is quite evident that in cases of hypertrophy the 
attacked part must be better nourished, otherwise it could never 
sustain the great increase in number and size of its cells. The 
hypertrophied organ is, in fact, indebted to the surrounding 
healthy parts for its additional nourishment ; in other words, 
the place of demand draws to itself the materials it requires. 
This is all the more necessary when the region of increased 
growth is deficient in, or altogether devoid of, chlorophyll, and 
thus quite dependent on the assimilating green parts. This 
is frequently the case, as in the scales of alder catkins attacked 
by Exoascm alni incanac, in the needles of silver fir deformed 
by Aecidium elatiiium, or in the yellow needles on spruce 
resulting from Aecidium coruscans. So also must the woody 
swellings of branches attacked by Aecidium elatinum, Gijmnu- 
sporangiicm scibinrie, and other fungi, be produced at the cost of 
neighbouring parts of the host. The hypertrophied organs be- 
have, in fact, like these plant-organs — flowers, roots, etc. — 
which are normally deficient in chlorophyll, and to which 
plastic material must be supplied. 

In other cases the part of a plant attacked by fungi behaves 
like a specialized organ, and, in combination with the fungus, 
attains to a certain degree of independence. The so-called 
"witches' brooms" furnish an interesting example. It is a well- 
known fact that the direction of growth of the main axis of 
plants is negatively geotropic, whereas that of the lateral branches 
is <mly a modified form of this condition. If the terminal bud 
of a tree {cjj. a spruce or fir) he. removed, then one or more 
lateral branches, or even buds of those branches, will exhibit 
an increased negative geotropism. This is very marked in 



MUTUALISM. 



89 



the case of the so-called " stonn-tirs " of the mouutains, on 
which are developed not a single apex, as in the normal fir, 
but many, each of which grows up like a little independent 
tree on the branches of the old stem. A similar result follows 
where a porticjn of a lateral l)ranch is planted as a " cutting," 
one bud grows directly upwards, the others form lateral branches. 
The stimulating effect which the removal of the terminal shoot 
produces on lateral branches is thus one which extends to a 
considerable distance. A stimulus of a somewhat similar nature 
appears to be exerted on buds attacked by certain fungi, so 




Kio. 111. — Witches' broom of Silver Fir, caused by AicUUam elatinitm. 
(v. Tuteiif phot.) 



that the sliDOt produced from such a bud no longer retains its 
normal direction of growth, Itut becomes negatively geotropic, 
like an independent plant. This marked negative geotropism 
is characteristic of all witches' l)rooms (Fig. 16), and shows 
clearly that they are no longer controlled by the same laws of 
grcnvth as the n(jrmal lateral branches. They have in addition 
other peculiarities not e\hil)ited l)y normal plants. Thus tlie 
witches' broom of the silver Hr causetl by iiiyccliiini ot 
Aa-uliuni di(tiiiiiiii is not evergreen, but bears needles whieh 
fall each autumn. Moreover, no witches' broom Itears (lowers 
or I'liiit; for example, that on the cherry (Fig. 5) ])roduce.s 
exclusively leaf-buds which unfnjil siiiiultaneousjy with ttie 



90 SYMBIOSIS. 

upeiiiug uf the llovver-buds of unattacked twigs, the normal 
foliage coming later. 

We have here an expression of the existence of a closer 
symbiotic relationship between the fungus and its host-branch, 
than between that host-branch and its main branch. It also 
shows that the host-branch is completely at the service of the 
fungus, although the latter is dependent on the former for its 
support. The host-lnanch is, at the same time, under the' 
necessity of conducting itself in the partnership in the way most 
suitable to the development of the fungus.^ Thus the asci of 
the Exoasceae are produced on the leaves of tlie witches' broom, 
and ripen as the normal leaves unfold, so that the spores 
are in a position suitable for successful infection of the young- 
normal leaves. 

From these facts it can be deduced, that parts of plants 
attacked by fungi exhibit that kind of symbiosis with the fungus 
which we call individuation, the joint community l)ehaving 
more or less as a parasite on the stem or branches of the host- 
plant. This is clearly the case where the attacked parts exhibit 
increased growth, and at the same time a diminished production 
of chloropliyll resulting from degeneration of chloroplasts. Such 
parts of plants are quite as individualized as the lichens, with the 
single distinction that they remain in communication with the 
parent plant and draw nourishment from it. 

There are, however, other cases where the chloroplasts are 
apparently increased, where at least they attain a lengthened 
duration of life. This is evident in certain instances first 
pointed out by Cornu, mentioned by De Bary, and on 
which I have made extended observations. Maples may 
be found in autunm on whose discoloured, withered leaves 
large green spots are still present. On Norway maple I have 
observed these spots, very conspicuous on almost every leaf, 
and especially on those of the lower crown. The green parts 
were beset with the white epiphytic mycelium and perithecia 
of Uncinula aceris. Cornu describes similar appearances accom- 
panying another Erysiijhe, certain Uredineae, and Cladosporinvi 
ilcndritwum. I have seen the same phenomenon regularly on 
the mountain maple on leaves carrying black spots of Rhythm a 

^ Plant-galls caused l)y animals also exliibit adaptations serviceable only for 
the gall-occnpant. 



MUTUALISM. 91 

jmndatum (Fig. 129). As other examples may be mentioned 
quince leaves, which I infected with Gymnofiporo.ngimn rlavarioe- 
formc, and leaves of Cyncmchvm Vincetoxiouni infested with 
Cronartium oschpia ileum. In all these cases, nutritive sub- 
stances seem to be still transmitted to attacked parts after 
death of the rest of the leaf. The attacked spots show also 
an independent behaviour in that they do not turn yellow 
liefore the fall of the leaf, but continue to work at the 
service of the parasite. One can even believe that these green 
islands, so long as inorganic substance and water are supplied 
to them, live with the fungus like lichens, especially those 
lichens whose algae obtain water and inorganic material direct, 
not thidugh the fungal-hyphae. 



CHAPTER IX. 
SYMBIOSIS. 

S 15. NUTEICISM. 

Foi; the greater number ul' the facts used in uur discussion 
of this peculiar phenomenon, we are indebted to Frank, who 
laid the basis of our knowledge in regard to it. We have 
chosen the expression Nutricism for reasons already stated 
(§ 14), and would only add that its scope is variable in different 
cases, and reaches its most comprehensive application in connec- 
tion with Frank's views on the so-called mycorhiza. We shall 
best explain the phenomenon by describing individual examples. 

In a number of cases the symbiosis between fungi and higher 
plants does not result in the fungus being supplied with organic 
nutriment l)y its host, but rather that the fungus is in no way 
indebted to the host-plant for nutriment, and may even, as in the 
lichens, convey solutions of inorganic materials to it, thus assist- 
ing in its nutrition. There are two cases distinguishable in this 
connection. In the first, the fungus lives in humus and in 
close external contact with the roots of its host, obtaining 
food for itself, and at tlie same time supplying its host 
with organic nutriment. In the other case, the fungus develops 
inside the root-cells of its host, and is probably nourished from 
that source, till on dying it gives up certain albuminoid sub- 
stances, which are absorbed and utilized by the host-plant. The 
parts of the roots which shelter the fungi, Frank has named 
" fungus-traps," the plants themselves being " fungus-digesting 
plants." 

The organs resulting from the symbiosis of root and fungus 



NLTKICISM. 93 

have been named niycorliiza ^ or t'ungus-roots. Where, however, 
new structures (swellings, etc.) are produced on the roots, as a 
result of symbiosis with fungi or bacteria, the name mycodomatia 
or fungus-chambers has been applied. 

One division of mycorliiza consists of those which livt- in 
humus, and act as intermediaries in supplying their hosts with 
nutritive material. In this case the fungus covers the host- 
root like an outer covering, forces itself between the cells of 
the outer layers, and produces haustorial branches in the interior 
of the host-cells. These Frank designates as ectotrophic 
mycorhiza. The remaining mycorhiza do not form such an 
external sheath, but live inside the fungus-traps, and produce 
tangled coils of hyphae in the root-cells of the host. These 
Frank distinguishes as endotrophic mycorhiza. 



Ectotrophic Mycorhiza. 

(1) On non-chlorophyllous plants living on humus. 

Kaminski - was the first to observe that Monotropa hi/jnijjitt/^, a 
non-chlorophyllous plant living rooted in forest-mould, possessed a 
compact root system devoid of root-hairs, but covereil with the 
hyphae of a fungus. At the same time, he expressed the belief 
that a symbiotic relationship existed between tlu- fungus and 
the roots of Mouoiropa, whereby the former supplied nutriment ttt 
the latter. The fungus clothes the growing point, and extends 
backwards to that part of the root which has ceased to elongate; 
there the mycelium penetrates •' inwards between the root-cells, 
and renuiins intercellular. The mycorhiza of Mo not rope thus 
showed complete agreement witli those known earliei- on the 
roots of (.'upuliferae,"* and since proved by Frank to have a \ery 
general distribution. -lohow'' has [)ointed out that an external 
mantle of fungi also exists round the root-apices of /li/popi(i/s 
/ii/l>uj)hdtyiti, a liolosapro])hytic plant (h'\did of ehhudjihyll. 

' Sar;iiiw, /i'o<lHi/)nl>i(>'« 01/ M yr<irrhr.i r sairlni /los SL'orfrairin, ISit.S. Willi 
itihiiograpliy. 
- Kiiiiiiii.ski, Ml III. il- la hoc. den Mciencen uatiir. ile Ch(rh(nii<i, '!'. iM, ISS'J. 
•'' Fniiik, Jlenrh/i d. dtutitch hotan. Gen., iHS'i. 

* MuUer, Stitditr over Skorjord soin liidraij Id Skovilri/kiiiiiijfiiK I'htori, IS7S. 
'^.FnliDW, " Die I lilotopliyllficicii I[uiiius|)llaMZtn," /'riiii/Hfi' lin's ./(ilirlnnli, ISS'.I. 



94 SYMBIOSIS. 

(2) On chlorophyllous plants. 

Frank has extended Kamin.ski'.s theory to include the 
niycorhiza of trees and other green plants. This assumption 
is founded on his observations of the common occurrence of 
mycorhiza on the Cupuliferae, and many other plants. He says 
that all trees are probably capable, under certain conditions, 
of entering into symbiosis with mycorhiza-fungi, and that in 
this way the tree is supplied not only with the necessary water 
and mineral food-constituents from the soil, but also with organic 
material derived directly from humus and decaying plant-remains. 
The tree is thus enabled, through the mycorhiza, to directly utilize 
organic vegetable remains. Frank supported this theory by 
anatomical investigation of the mycorhiza of numerous plants 
and later by physiological experiments. The latter consist in the 
comparative cultivation of seedling forest-trees in a sterilized 
humus-soil, and also in a non-sterilized soil containing the 
mycorhiza-fungi. These experiments showed, in the case of 
beech, that those trees in sterilized soil with normal roots and 
root-hairs without mycorhiza, were poorly developed, and died 
after several years, while the others with mycorhiza grew 
vigorously. 

Frank also pointed out that mycorhiza are developed only 
in soils containing humus, and in the humus layer. He 
assumes that the fungus conveys to the tree-roots not only 
carl}on compounds, but also, since the mycorhiza-cells contain 
no nitric acid, nitrogen in organic compounds. 

The mycorhiza-caps suppress the formation of root-hairs, Ijut 
I have frequently seen hairs on neighbouring roots or on parts 
of the same root behind the fungus-cap (Figs. 17 and 18). In 
soil free from humus, root-hairs are always present and carry 
on their work normally. Schlicht ^ found that pines growing 
in poor sandy soil without humus had no mycorhiza, but only 
normal root-hairs. lieess found that pines near Erlangen had 
quite as many rootlets without mycorhiza as with. It would 
thus appear that while every tree possesses a number of roots 
with fungus on them, yet the complete transformation of the 
whole root-system to mycorhiza is by no means so general as 

^ Schlicht, Inaug. Disserttation, Berlin, 1889, p. 9. 
Frank, Ber. d. deufsch. hot an. Ges., 1892, p. 583. 
Reess, Bey: d. deiifsch. hotan. Ges., 1885, p. '295. 



ECTuTKurmc MYCUKHIZA. 



95 




Fin. 17.— Sjiruco scedhii),' in tliinl ycMr, fi-oNvn in il;iy-l..:ini. Tyi)ical fur.illiko 
inycorhiza aro iibHout. Tlic «tr<jn>f root t<i the ri^rlit 't.lii>WH, on "its newer luirtM 
and on all latcr.il root.s, only root-hairs and no fiintfiiH. The reniaininK rootx aro 
not nioditieil in any way— some aro covered with Iuobo fungal lap.i, otIiurH 
have Ixith fungal capH and root-hairM, while otliers are iniito free from fiini,'!. 
<v. Tul«;uf phot.) 



96 



SYMBIOSIS. 



in Monotnqxi. The root-system of a tree has not only to secure 
nourishment, Imt also the rigidity and stability of the tree.^ 
This latter can only be attained by a wide distribution of roots 
in the firm subsoil free from humus, where normal roots with 
root-hairs will be formed. The nursing function of the mycorhiza 
seems thus to be less important than in the case of Monoinqm. 




Fig. is. — Miicorhiza of Pinus Cembra. A, Typical mj'corhiza. B, Root sliowiug 
clusters of mycorhiza as well as portions clad with fine root-hairs. C, Rootlet 
exhibiting button-like thickenings externally devoid of a fungoid mantle, but 
internally completely destroyed by m.vcelinm. D, Section through a thickened 
bi'anch of a mycorhiza-clnster : a, fungoid mantle; l>, fungoid tissue between 
the cells of the root, rendering them unrecognizable except by their large nxiclei ; 
the inner parts contain no fungi, (v. Tubeuf del.) 

My newest investigations on this subject - show that, amongst 
the gymnospermous forest-trees, the Abietineae alone have roots 
externally clothed with a fungus ; the remaining groups have 
all endophytic mycorhiza. The Abietineae have frequently only 
a fine mantle of fungus on their rootlets, and do not produce the 
tufts of short, branched roots so characteristic of mycorhiza in 
general. Frank does not seem to be altogether correct in his 
view that the Abietineae are almost or quite incapable of multi- 
plication by slips, because they would then require to exist for a 
time without mycorhiza. Probably there is some other reason 
for this, because the Salicaceae {e.g. Poplars), w^hich have typical 
coral-branched mycorhiza, are almost exclusively multiplied by 
slips. 

^ Hoveler, ("lib. die Verwertlmiig d. Hiiums Ijei d. Ernaliiung d. cldoiopliyll- 
filhrenden Pflanzen." Inaug. Diss., Berlin, 1892}, states that roots are able to 
utilize the soil-constituents without aid of fvingi. 

-Tubeuf; For.st.-naturwi>is. Zeitschri/t, 1896. 



ECTOTHOPHIC MYOjUHIZA. 07 

After the mycurhiza have functioned as sueli for some time, 
the fungoid sheath, as wtdl as the hyphae contained in the 
curtex of the root outside the endodermis, are thrown off hy 
internal cork-formation. This is, liowever, not always the case, 
for the fungus may penetrate further and develo}» injurious para- 
sitic characteristics; this is so with J^n/i/saccui/t^ and Ehiphdiniicisr 

Endotrophic Mycorhiza. 

(1) On non-chlorophyllous plants living in humus. 

Certain Urchideae — Nruttia Niihis uris, Epipixjon frutc/iai, 
Croodycra rcpeiu, etc., as well as some Gentianeae,'^ possess 
roots developed as endotroi)hic mycorhiza. In Cora/liorhiza the 
fungus frequents the short coral-like rhizomes. The i'ungus in 
these eases penetrates inti> the cells of the root-corte.x, and 
there forms a hall or coil of hyphae ; it neither covers the 
roots externally nor inhabits the epidermal cells, so that the 
production of root-hairs goes on (juite normally. From the 
circumstance that the hyphal coils become emptied and only 
the remains of walls are left in tlie still living root-cells, Frank 
concludes that the fungus after Ijeing nourished for a time by 
tlie root-cells is ultimately deprived of its contents by them. 
< )n this account he calls these roots " fungus-traps," and the 
plants possessing them " fungus-dige.sting plants." It must be 
remarked, however, that the fungus grows onwards from older 
parts of the roots to younger, so that here, as in many other 
ca.ses, the contents of the hyphae may pass from the older into 
the younger hy})hae. Frank himself suggests-* the possibility 
that the rocjts take u]) nutriment without aid from the enclosed 
I'ungus, and also that the latter receives its food parasitically 
from the former. What advantage the roots may receive from 
reab.sorption of footl, which they have i)reviously supplied to the 
tungus, has not been closely investigated, nor has the (juestion 
whether the roots are in a jiosition to nourish the plants eipially 
well without fungi. 

Tlie root-fungi of < licliideae havi! long been kunwn.aiid IMeller' 

' llniiiM, "Beitnij,' /.. Kfimtiiiss il. (Jatliiiit; I'ulysarcnni," F/arti, IS!I4. 
-' KecHH, " Uiitei-MUcii. iil)er il. MirKcliti iill<l, ' liili/idij. /intaii. 1SS7. 
' Prini/Hfuim't Jahrlmrh, XVI. iiiitl XX. 

* I'raiik, l.'Inlntrh il. /{o/niilk \>. --'(iT. '• Lditilnirlh. Jnliilnirh, |S77. 

(i 



98 



SYMBIOSIS. 



suggested that the reduced fonnation of hairs on their roots was 

due to the fungus-hyphae behaving physiologically as root-hairs. 

Johovv, in opposition to Frank, states that the non-chloro- 

phyllous Wullschlacgdia, a relative of Neottia, shows no trace of 





Fl(i. 19. — Coralliorhiza innate. Br. 
(v. Tubeuf phot.) 



Fig. 20. — Neottia Nidus avis Rich, 
(v. Tubeuf phot.) 

fungal hyphae about its roots, and yet derives nourishment direct 
from humus. The same author found among roots of the Bw-- 
manniaceae, some free from fungi, and some with the rind, and 
even the epidermis full of mycelium. 

(2) On chlorophyllous plants living amongst humus. 

Accordi^ng to the investigations of Frank, all our Ericaceae, 
Epacrideae, and Empetraceae, living in the humus of moor, heath, 



ENDOTKOI'HIC MYC'oRHIZA. 99 

or wood, possess endotiophie laycorliizii. These appear as fine, 
elongated rootlets whose epidermal cells never develop as root- 
hairs, Ijut become filled with coils of fungoid hyphae. 

Schlicht mentions a large number of herbaceous plants out of 
the most widely separated genera of Angiosperms, the finer roots 
(jf which he found regularly developed as myeorhiza. These, how- 
ever, possess in addition normal root-hairs, which without doubt 
function as such. The endotrophic coils of fungi are situated in 
the inner cells of the cortex surrounding the conductive tissues, 
and Schlicht regards them as important in transmitting to the 
conducting tissues substances taken up by the root-hairs. Since, 
however, the fungus inhabits living cortical cells, it is quite 
possible that these transmit the food-materials direct without 
tile aid of the fungus. 

Schlicht found endotrophic myeorhiza on Leguminosae, while 
Frank found them on the alder, both being distinct from the 
well-known tubercles of these plants. 

Kiihn^ and Goebel- found endophytic root-fungi on Marat- 
tiaceae, Ophioglosseae, and Lyccqiodivm ; Kiihn also found spores 
which resembled those of Schinziq. 

Endotrophic myeorhiza are also present in saprophytic green 
orchids, as well as in hemi-saprophytic orchids without green 
colour; and Meineke^ found hyphae passing through the little 
cells of the endodermis of the aerial roots of orchids into the 
mucilage-masses of the rind-parenchyma. Schimper found fungi 
present on the adherent side of the roots of epiphytic orchids. 

Mycodomatia of Myricaceae, Elaeagnaceae, and the 

Alder.^ 

The above-mentioned plants possess a well-developed and 
normal root-system, and also chaiacteristic lateral outgrowths, 

' Kuhii, " UiitersULliiiiigeii uli. d. Aiiat. d. Miiriittiaceeii," F/ora, 1889. 
- (ioehel, liolHU. Zeitiiiuj, 1887. 

•' Mfineke, " Beiti'. /.. Anat. il. LuftMurzelu d. Oicliideeii," Flora, iSfM. 
* IJihliogiaphy — WOioiiin, Mem. di laind. dtn hvI. di- St. Pi'limhurii, 18ti(j. 

Hi'iinclidrst, Jitr. il. dinlKrh. hofaii. (it/i., ISS."). 

I{ruiu:li<ir.st, (Jiittrn. aits d. holaii. Intt. Tiihiinjni, 1SS(). 

MollcT, her. d. dintsch. hotan. (.Itx., 1885 aiul 18JK). 

Frank, Btr. d. ihutmh. Uolau. Utn., 1887 mid 188!l. 

AlkiiiHoii, " 'I'lie genus Ftankiii in U.S. Anii-rica," 'J'orn >/ 
CI III. linlhtiii, ISIfJ, |,. 171. with plat.- 



100 SYMBIOSIS. 



which may increase to very large tubers, with surfaces resemb- 
lino- a bunch of grapes (Fig. 21). In the large cells of the 
middle layers of the primary root-cortex of these growths, 
coils of very fine fungus-threads are sheltered ; these extend 
year after year into the younger parts of the enlarging tuber- 
cles, and gradually disappear in the older parts. What may 
be the significance of these structures for plants possessing 




Fig. i\. — Frankia n/ni. Root-tuliereles un the Alder, (v. Tubevif jiliot.) 

chlorophyll and furnished with normal roots is as yet unknown. 
Plants which have grown well for years in water-cultures do not 
show them. On account of the cork-covering with which these 
tubercles are furnished, it would seem that they are not adapted 
for taking nourishment out of the soil. 

Woronin described them first on the alder. Warming on 
Klaeagnaceae, while jMiJller proved their fungal origin. 

The species of fungi wdiich produce these tubercles liave been 



MYCODOMATIA OF THK ALDEIl, KTC. 



101 



provisionally distiiiLiuished as Frankia alni (Wor.) on alder, and 
Frankia Brunchorstii (Moll.) on Mi/ rim Gale. 

Hiltner/ after a series of experiments, states that first-year 
alders without tnbercles do not thrive in soil free from nitrogen, 
nor do they take up nitrogen from the atmosphere ; when, 
liowever, provided with root-tubercles they assimilate nitrogen. 
The tubercles also functionate in water, and soil rich in nitrogen 
lias the att'ect of slightly increasing the assimilation of that 
element. The tubercle-fungus is at first parasitic on the alder, 
and is only of use to the plant after the tubercles have fully 
developed. 



Mycodomatia of the Leguminosae. 

All Legumint)sae growing in their native soils exhibit the 
so-called tuljercles. These are accessory formations of the 
primary root-riiul and are furnished witli 
vascular liundles connected with the ro(tt- 
bundles ; they consist of a cortex of normal 
cells surrounding an inner large-celled 
parenchyma with turbid cell-contents con- 
sisting of numbers of bacteria, {Bacterium 
radicola, Beyerink, or RMzobinm Icguminos- 
amm, Frank.) - 

Frank describes minutely the formation 
of these tubercles.^ The short rod-shaped 
microbe forces its way into a root-hair 
or epidermal cell, multiplies there, and is 
conducted to the inner cortical cells by 
plasma-threads continuous through the 
(x'll-walls. A rapid division of the innt-r 
cortical cells is set u]), till a tubercle is 
formed, which may still further increase 
by continued cell-division from a meristem 
at its apex. The bacteria multiply simul- 
taneously, and are transferred into thi' 
great change comes over most of them 




Kli-.. ■l-l. — nii,:olH /,;;.•„,- 

iiimaroii. Uoot-tulx.'ivli.'S <>ii 
(•'iiiigdi tincloi-Ui. (v. TiOx'uf 
l.hot.) 



new cells where a 
ihev enlarge ver\ 



' Hiltner, " Ueber <1. Hedeutuiig il. Wurzelkacilklifii v. Alini.s glutiiio.Hii, " 
Xohl»'s LnitilirirtMika/t. l'ersiuh-i-n((tlio>ien, 189"). 

-■ Woroniii, Mi'ni. de rnaul. ilfx sci. df St. Pt'tershitrij, 18S(». 
■' Li/irhmli ,/. liotauik, \t. 'J71. 



102 



SYMBIOSIS. 



much and become club-shaped or dichotomously branched 
bodies without power of division, which may be designated 
" bacteroids." ^ Brunchorst found the contents of the bacteroids 




Fig. 23. — Rhizobiwa legwuinosarum. Root-tubercles on Robinia Fseudacacia 
(V. Tubeiif phot.) 



to disappear at the time of the fruit-formation of the host- 
plant. A small number of microbe-bodies still remain, according 
to Frank's observations, capable of division, and these, after 

1 According to Moller, they undergo fatty degeneration. 



MYCODUMATIA oF THK LEtiUMINOSAK. 103 

decay and break-up of the tubercles, reach the soil ready to 
bring al)out new infections. 

The great importance of the tubercles of Leguminosae is 
that the plants bearing them are capal)le of taking up free 
nitrogen from the atmosphere and utilizing it, while without 
the tubercles they could not do so.^ If Leguminosae be grown 
in soil rich in nitrogenous ftjod-substances, the tubercles are 
not So well developed. 

According to Schneider,- the host-plant under the iutluence 
of the Rhizoliiaiii produces cellulose tubes, which become lilled 
with the fungus. According to Jieyerink,^ these tubes consist 
of bacterial slime secreted by the llhizohiiim. The epidermal 
tissue of the tubercles consists of a loose layer of cork with 
many intercellular spaces; this arrangement is stated by Frank ^ 
to facilitate the usual transpiration.^ 

' Hellriegel u. Wilfiuth, Btrkhte d. deiitsrh. bo/an. TrVs., 1SS9; also Ziitsrhrift 
f. d. RubtiizHcktr-Indwitrie, 1S88. 

- Ber. d. deutsch. hotan. Ges., 1894, p. 11. 

'■^Centralhl. f. Bacterologie u. Para-fitenkititdi:, 1S94. 

* Ber. d. deutsch. hotan. Ges., 1892. 

■'' Schneiiler (Bulletin of the Torrey Cluh, 1892), gives a sliort account of 
AiMciican Bkizobia, and refers to the chief works on tills subject. (E<iit.) 



PART SECOND. 

SYSTEMATIC AliEANGEMENT OF THE CEYPTOGAMIC 

PARASITES. 

I. THE PATHOGENIC FUNC4I OF PLANTS. 

The vegetative body of the Fungi is a tlialloid structure 
known as a mycelium, and composed of one or more hyphae. 
The hyphae are cells included in a firm wall of fungus-cellulose 
of varying composition ; they grow apically, and hence are 
always filamentous in shape. In the simpler cases, the mycelium 
is a non-septate tube unbranched or branched ; in the more 
complex forms, it consists of a system of hyphae divided into 
cells by cross-septa. By the union and anastomosing of numerous 
hyphae, a tissue may be formed not unlike the parenchyma of 
higher plants, hence receiving the name pseudo-parenchyma. 
From this tissue may arise distinct structures of many kinds, 
such as the sporophores of the Polyporeae, or strands of 
tissue like the well-known rhizomorphs of Agaricus melleiis, 
or masses of resting-mycelium like the sclerotia of Claviceps. 
It is also not uncommon to find a differentiation in the structure 
of the vegetative mycelium in the form of lateral outgrowths- 
of the hyphae, developed as organs for the collection of nutri- 
ment — the haustoria, — or as organs of attachment — appressoria. 
lieproduction may take place sexually by the union of two 
cells or nuclei, the product of which is a spore or zygote capable 
of germination ; or asexually by means of endogenous spores 
or swarm-spores, or by the abjunction of conidia of different 
kinds. Sexual reproduction is common amongst the lower 
fungi, but in the higher forms, if existent at all, it is very 



THE I'ATHUliEMC FlXCil OK I'LANTS. 105 

obscure and is replaced liy iiuinerous and complex mode.^ of 
asexual multiplication. 

The lower forms of fungi, in the structure of the thallus, mode 
of reproduction, and adaptation to an aquatic life, exhibit distinct 
relationship with the Algae, particularly with the Siphoium. 

Since the fungi do not possess chlorophyll, their nutrition 
is carried out by the absorption of organized material in a 
saprophytic or parasitic manner. Parasitic fungi are the cause 
of numerous and dangerous diseases of plants, whereas the} 
only rarely bring about a diseased condition of the animal boily. 
Bacteria on the other hand, which cause so many animal diseases, 
seldom affect plants injuriously. While many parasites are 
strictly limited to a parasitic mode of life, a large nund.ier 
naturally spend a part of their lives as saprophytes, and others 
may be made to do so artificially on nutritive sul)Strata 
under suitable conditions. The latter method forms in fact a 
valuable aid for completing our imperfect knowledge of the 
life-histories of parasitic forms. In additifjn to the well-marked 
parasitic fungi, there are many saprophytic forms which liecome 
jjarasitic for a relatively short time or under special conditions 
of environment. 

The Fungi are divisible into two large groups, tiie lower 
fungi (I'hycomycetes) and higlier fungi (^Mycomycetes). 

The systems instituted by various investigators difler not 
a little from each other. Three of tlie principal are : 

Dk Bary. Zopf. Brkkkld. 

( 1 ) Ph_\ comycetes (1) Phycomycetes (1) Pliycomycetes 

(2) Ustilagineae (2) Myc-oiuvcetes (2) Hiylier Fungi* 
(;i) Asconivcetes («) Basidiornycetes {a) Mescmiyi-etes 

(4) riediiieat' {!>) T'lvdiiieae Hemiasei — Hi-milia.-idii 

(.")) Basididiiiycctcs {<:) I'.stilayineae {h) Mycoinyofte.s 

('/) Ascomycete.s Ascoiiiycetes— }5asidio- 

iiiycetes 

We .shall in the present work consider the Fungi in the 
following order : 

Lower Fungi or I'hycomycetes: 

Chytridiaceae, Zygomycetes, Oomycrtrs, 
Higher Fungi or Alyconiyceles : 

Ascomycetes. 

Fstilagineae, Frcdinrae, r.asidioniycctfs. 



106 PHYCOMYCETES. 

A. Lower Fungi (Phycomycetes).i 

The lower fungi possess, at least in tlieir earlier stages, 
single-celled mycelia, which may in the higher families become 
branched. They reproduce sexually by oospores or zygospores, 
asexually by conidia. The Phycomycetes are divided into : 
Chytridiaccae, Zjjgoviijcetfs, and Oomycctes. 

(1) CHYTRIDIACEAE. 

The fungi of this family are chietiy parasites on aquatic 
plants, or on land-plants inhabiting moist places. The my- 
celium is one-celled, very rudimentary, or altogether absent. 
Asexual reproduction takes place by the formation of zoo- 
sporangia which usually produce uniciliate swarm-spores. Sexual 
reproduction is rare, and is effected by fructification of one 
cell by a fertilization-tube from another ; the resulting bodies 
are zoosporangia which on germination set free swarm-spores. 
Hibernation is effected by resting-spores produced from sporangia 
in which the formation of swarm-spores is suppressed, and 
which become clothed in a thick membrane. Some of the 
species cause interesting deformations on the organs of plants. 

The Chytridiaccae include the families of Olpidiaceae, Synchy- 
triaceae, Cladochytriacme, Bhizidiaccae, Hypocliyiriaccae, and Oocliy- 
triaceae. Of these, only the first three contain species parasitic 
on higher plants. They occur epidemic only in moist situations, 
and rarely cause great damage to cultivated plants. 

OLPIDIACEAE. 

The whole vegetative body becomes a single zoosporangium 
or a resting-spore. Sexual reproduction is very rare. 

Olpidium. 

The vegetative body consists of a naked mass of protoplasm, 
the product of a single spore. This becomes later enveloped 
in a thin wall of cellulose, and forms a zoosporangium with a 
long neck through which the cell-contents are ejected as 
uniciliate swarm-spores. The cellulose membrane may become 
thicker and a resting-spore (sporangium) result, which in course 
of time germinates and gives off swarm-spores. 

' Bibliography — A. Fischer in Rabeiihorst's Krypfoqamcn Flora, 1892. 
Schroeter in Engler-Prantl PJlanzen/amiiien, 1892. 



0LPIDIU3I. 



10^ 



Olpidium brassicae, (Wor.)^ { = Chytridiinii brassicac, Wor.) 
Cabliage-sec'dliii,i;s die if tliis fungus tinds its way into the tissue 
at the neck of the root. The spherical sporangia are formed at 
this place, and their long necks project out of the cells enabling 
the uniciliate swarm-spores to escape. IJesting-spores with a 
warty thickened membrane occur in the cells of the epidermis. 




Fig. 24. — Chi/tridium bnuncae, Wor. Cell contiiiiiiiig three sporangia, two of 
which are discharging zoospores ; one sporangium is already empty. Resting- 
spores inside the cells of a cabVjage-plant. (.\fter Woronin.) 



The disease is favoured by moisture, and restricted by dry 
surroundings. Ground subject to attack should be planted 
witli crops other than cabbage. 

Olpidium trifolii, Schroet. { = >Si/nchi/trii(iii trifoUi, Pass.) 
rioiluce.s defurmatioii of the leaves and petioles of TrifvUutn 
njii/i.-i. The fungus lives in the epidermal cells. 

Olpidium lemnae, Fiseh., in epidermal cells of Lrmna. 

Olpidium simulans. De Bary and Wor., in Taraxacum 

offi.ciiiiilr. 

A number of <jther species inhabit algae, spores, fungus- 
mycelium, pollen -grains, and eggs of Rutatoria. 

The genera lircasia, Pacvdolpidium, O/pvfiojisifi, I'lcotrachilus, 
Eitrofjclla, Pleolpidimn are ])arasiti(' only nn Inwcr jilaiits, espcrially 
on algae. 

SYNCHYTRIACEAE. 

llif whi)lc mycelium divides up iiiln ;i number i)f spurangia, 
wliich remain together as a sorus. 'I'hc winter resting-spores 

' Wnioiiin, /'riii'j'ihi iiii'i Jdhrliiirh /. iriss. lintauih, ls7S(l'"i^'. .SI). 



108 PHYCOMYCETES. 

originate from the whole inyceliuni or parts thereof, and are 
isolated or united into a sorus. 



Synchytrium and Pycnochytrium.^ 

Here, as in Olpiclivm, the mycelial liyphae are wanting, and the 
vegetative l)ody escapes from the spore as a naked mass of 
plasma, which is later enclosed in a membrane. This vegetative 
body may also develop into a sorus of thin-walled sporangia : 
these separate in water, and each ejects from a pore numerous 
swarm-spores with a single long ciliuni. In the event of resting- 
spores being formed, the membrane of the vegetative body 
becomes thickened into a brown exospore. The resting-spores on 
germination liberate their contents as a single mass, or as several 
zoospores. In the former case the single mass divides at once 
into zoospores, or into a sorus of sporangia, which ultimately 
give off zoospores. 

These fungi are found in the interior of cells, especially of 
the epidermis. The one cell inhabited by the fungus grows 
out as a simple papilla, or several neighbouring cells are also 
modified, and grow out along with the original one to form a 
gall-like sw^elling. The species of Synchytrium generally in- 
habit the epidermal cells of land plants, yet disease caused 
by them is commoner in moist than in dry situations. They 
cause so slight deformation and damage to cultivated plants that 
they are of little practical importance. 

The Pycnochytrium of I)e Bary is regarded by Fischer as a 
sub-genus, by Schroeter as a genus. 

Synchytrium. 

The sori of zoosporangia are formed by direct division of 
the mature sporophore, and are enclosed in the colourless 
membrane of the mother-cell. 

Synchytrium taraxaci, De Bary and Wor. (U. S. America).- 
This produces, especially on Taraxacum, warty galls composed of 
a diseased epidermal cell, enlarged and surrounded by a wall of 

^Schroeter: Cohn's Beitrar/e z. BioL d. Pjlanzen I., 187o, and in Emjhr-Prantl 
PJlanzenfcimilien, 1892. 

De Bary and Woronin, Bericht. d. natfornch. Gex. zu Freibury, 1863. 

- We propose to indicate in this way species recorded in Seymour and Farlovv's 
"Host-index" for North America; British species by (Britain). (Edit.) 



SYNCHYTJUUM. 



109 



less swollen neighbouring epidermal cells. The sporangia C()ntain 
reddish-yellow drops of oil, so that the swellings appear yellow. 
The organs attacked are much 
distorted and more or less 
stunted. 

The same fungus occurs (»n 
other Compositae, and is pro- 
bably identical with S. sun- 
t/uincum of Schroeter, which 
l^roduces dark red, crusty swell- 
ings on Cirsium palustrc and 
Ore pis biennis. 

Along with *S^. taraxaci one 
often finds Olpidium simulans. 

S. fulgens, Schroeter (U. S. 
America), produces reddish- 
yellow swellings on the leaves 
of Oenothera biennis and 0. 

, . Fig. 25. — Simchytriuui taroxcci. Leaves of 

mnrirata ; when reStnig-SpOreS ra,iu:aciiM oikdnale so deformed by the funpis 

, ' p , ^ that the laminae are all more or less undeveloped. 

appear they lorm brown crusts, (v. xubeuf phot.) 

The sori of zoosporangia are 

detached from the host-plant as single sporangia, which 

become scattered over the leaves. 

S. trifolii, Pa.ss. { — (HpiiUvm trifolii, Schroeter), is as yet 
little known. 

Other American species are : — 

S. papillatum, Fail, on (hmnium. 

S. decipiens, Farl., on Ani'p)hiearpara. 

S. vaccinii, Thomas,^ on Vaeciniani, 
Ilhododendron, etc. 




(jualtln rui, Kill in in. 



Pycnochytrium. 

The .sori of zoosporangia are not ]jroduced tliri'dly troiu the 
mature sporophoie, Itut tlie contents of the sporopliore pas.s out 
by a fine (jpi-niiig and form a thin-walled vesicle, the ]>r(itnpl;ism 
of which l)reaks uji intn sporangia. 

Schroeter divides the genus into two sub-genera. 

(A) Mi.siir/ii/trii'tn. 'J'he discliarge of the original s|ioinph(ire 



' Hiilstcd, " ('ninl)eiTy gall-fimgiis ' 
1SM». With tiguix's. 



\. J, IS,, J A'jrir. Coll. liuUtl. »>4, l>iM 



110 



PHYCOMYCETES. 



and the formation of zoosporangia take place in the cells of the 
living host-plant. In addition, spores are formed which have 
a resting period. 

(B) Only one kind of spore is formed ; it has a resting period, 
and only proceeds to produce sori of zoosporangia after decay 
of the host-plant. 

(a) Chrysochytrium : protoplasm contains a yellow oil. 

(b) Leucochytrium : protoplasm colourless. 

Each of these divisions is sub-divided into forms with simple 
vesicles, and those with compound. 

Mesochytrium. 

Synchytrium (Pycnochytrium) succisae, De Bary and Wor.^ 
This parasite forms warty swellings and yellow spots, generally 




Fig. 26. — Synchytrium succisae. A, A mature sporocarp inside its host-cell. 
B, In the uj^per part of the cell a sorus of swarm-sporangia after escaping from 
its covering, which lies below it. C, Isolated swarm-sporangium. D, Swarm- 
spores. (After Schroeter.) 



on the radical leaves and base of stem of Scahiosa succisa. 
Infection is l)rought about in damp situations by means of 
swarm-spores. These have a single cilium, and bore their way 
into the host-cell. After entrance, they produce a plasma-mass, 
which becomes enclosed in a delicate membrane. The cell so 
formed sprouts at its uppermost pole, and gives rise to a new 
spherical cell, into which the older discharges itself. In the 
second cell numerous small sporangia are formed, so that it 
represents a sporangial sorus ; beside it is always found the 
empty membrane of the first cell. The sorus breaks up later 
into single sporangia, which on opening, set free their contents 

1 Schroeter, " Pflanzenparasiten aiis d. Gattuiig Synchytrium.'' Cohii's Beitr, z. 
Biolorj. d. Pflanzen, 1875. 



PYCNOCHYTKUM. Ill 

HS zoospores swarnuni; by lueaiis of a cilium. In addition, 
resting-spores are developed singly or in groups. 

The first etlect on the host-cell of the entrance of a swarm- 
spore is that it becomes distinctly larger. At the same time 
neighbouring cells are so stimulated that they multiply and 
form a prominent ring-shaped swelling. The sporangia discharge 
their zoospores on the host-plant itself, and these pass into 
other cells of the swelling ; here they form resting-spores and 
the host-cells die. Schroeter states that the resting-spores may 
be found from August onwards. 

S. stellariae. Fuck. ( )n Sfella.rio media and S. niinitriim. 
The reddish-yellow hemispherical swellings are produced on leaves, 
stems, tiower-stalks, and sepals, either isolated or as a crust. 
The resting-spores generally form brown crusts. Tlie host-leaves 
may be somewhat crumpled, but beyond this undergo little de- 
formation.^ 

Chrysochytrium. 

( 1 ) Forming simple vesicles : 

Synchytrium myosotidis, Kiihn (U. S. America). The ejti- 
deiiiial eell- when allacked swell up to form club-shaped 
processes, while the cells with no fungus renuiin unaltered. 
The normal hairs of the hf»st-plant are fewer on diseased than 
on healthy parts. This parasite attacks Uoragineae, aj. Mi/osafis 
stnda, Litho-sjxnnicm arrcnsc. 

S. cupulatum, Thomas, produces red eruptions on J'vtinfiUn 
ar(jinf<" and Driins Dctoprtalo. ; diseased cells of the host-plant 
contain red saj). 

S. punctum, Somkin. On PUmtiKjo }<iiuri)\iifii and /'. iimUn' 

S. laetum, Schroet. On (lagra. 

el) Forming comjidund vesicles: 

S. aureum, Schroet. Attacks many herbaceous plants as well 
as leaves of many shrubs and trees. Frequent on Li/si)ii<ic/ii<i 
Nummvluria, Fragaria, etc. The cells attacked an- swollen and 
enclosed in a patch of enlarged neighljouring cells. 

S. pilificum, Thomas. On I'ulintilhi Tdninntilln. The 
vesicles are hemispherical, and beai- on their summits a tuft 
of abiioiiually elongated hairs. Thomas- fouml this species 

' ('leinlenin {liotunical <lu\ttli, lh!)4, p. 'J96) (le.scrilius iiinl li;,'mi> .1 Si/nclii/lihiiit 
on Si'ltaria iiwlin in America (K<lit.). 

■-/;./•. 1/. >l.,ii.irh. hofan. lUi., ISSJ^, |.. 4!H;. 



112 



PHYCOMYCETES. 



on stems, tiovver-stalks, radical and cauline leaves, and tloral 
envelopes. 

Leucochytrium. 

(1) Forming simple vesicles: 

S. punctatum, Schroet. On Gcujca pratcnds. 

S. rubrocinctum, Magnus, forms little red eruptions on Saxi- 
J'i'"ll" ijrdiiiihdii, the cell-sap of the host-plant becoming red. 

S. alpinum, Thomas. On Viola hiflora. 

S. anomalum, Schroet. (U. S. America). On Adoxa Moscha- 
tcHlii'i, less common on Ilcvavnndus Ficaria, Isopijrum tludidroides 
and Eiimrx Acctosa. The size and shape of the swellings, as well 
as of the spores, are very variable. 

(2) Forming compound vesicles : 

S. anemones, De Bary and Wor. (U. S. America). On 
u-l/icmo/ie nemorosa, A. raniinculoidc^ and Thalictrum purpara- 




FiG. 27. — Synchytriv.m anemones. The sporocarps form black points on leaves, 
petioles and perianth of the Anemone ; the laminae are also stunted and distorted, 
(v. Tubeuf del.) 



scens, attacking stems, leaves, or flowers, and forming eruptions 
whose cells contain a red sap. In very bad cases, crumpling 
and swelling of attacked organs occur. 



PYCNOCHYTRIUM. lll^ 

S. globosum, Schroet. AVliere the attack is severe, tliis causes 
pearly swellings or incrustations ; it frequents plants like Viula, 
Gal'iiiiii, Afliilhd, Sonrhi's, Mj/ytofis. 

S. mercurialis, Fuck., is very common on Mi nu rial is i^c'cnnis 
though seldom injurious to it. One severe case is thus de- 
scribed by Schroeter : " In spring the stem of the plant was 
covered by a thick uneven glassy crust, which in course of time 
became raised into wing-like processes running down the stem 
and coated on both sides with white granules of the hnmature 
parasite : the leaves were completely rolled together, crumpled, 
and covered with glistening prominences as with tine silver sand. 
The plant in this condition developed poorly, scarcely flowered, 
and soon died, so that by the end of Sept end ler few diseased 
examples could be found." 

CLADOCHYTRIACEAE. 

The vegetative body is frequently a branched mycelium. It 
lives intercellular as a saprophyte, or intracellular as a parasite, 
and forms intercalary or terminal swellings, in which zoospor- 
angia or resting-spores are produced, then it disappears. Sexual 
reproduction does not occur. The parasite lives in and forms 
swellings on aquatic plants, or land plants in moist situations. 
The genera UropJilyctis and Plii/sodcnna contain species parasitic 
on higher plants ; together with the saprophytic Cladosporanijivm, 
these are regarded by Fischer as sub-genera of Cladocliylrivm, 
and as such they are also here regarded. 

UroiMijdis has both zoosporangia and resting-spores, Fhi/so- 
dtrma has only resting spores, Chidos2X)rangiiim only zoiispt)r- 
angia. 

Urophlyctis. 

'J'he delicate mycelium is uubranched, <u cnly sliiiliil\ 
branched, and lives endophytic, boring through the walls of 
llie host-plant. At the place where a hyitha i-nters a hust- 
plant it forms a swelling or collecting cell (sammel/ell), whiih 
generally becomes dilferenliateil into a larger cell rich in contents, 
and an outer small(?r one with IV'W contents, but with fine 
terminal bristles. From llie collecting cells new hyphae 
originate and proihice other collecting cells in neighbouring 
host-cells. The /.oosj)oiangia are situatt'd outsidr the host-cells. 

II 



1 1 4 PHYCOMYCETES. 

but send a hyphal process inside, which branches into a tuft 
of rhizoids. liestinf^-spores may be found, several in each cell. 

Cladochytrium (Urophlyctis) pulposum, (Wallr.), causes on 
leaves, stems, and Howers of Chcnopodivm and Atrijjlcc glassy 
swellings, in the undermost cells of which are situated the 
-zoosporangia. The resting- spores have brown shining walls and 
lie inside the cells. The zoospores are uniciliate. 

CI. (Ur.) butomi, Biisgen. On leaves of BiUomus umbellatus. 
Black spores are produced containing resting-spores. The col- 
lecting cells have tufts of hair. 

Physoderma. 

Zoosporangia are absent. liesting-spores formed, several in 
«ach host-cell. 

Cladochytrium (Phy.) menyanthis, De Bary (U. S. America). 
On leaves and petioles of Mcnyanthes trifoliata this forms 
vesicles containing resting-spores. The collecting cells have 
terminal hair-tufts. Diseased leaves are generally smallei' than 
Ileal thy. 

CI. (Phys.) flammulae, Biisgen, forms little swellings on 
leaves of Ranunculus Flammula. 

CI. (Phys.) Kriegerianum, Magnus, causes transparent swell- 
ings on Cavil m Cariil. 

CI. (Phys.) iridis, De Bary, on Irk inmdacorus. 

Fischer mentions other species on Scirpus, AlUma, Ranunculus, 
Fotentilla anscrina, Silaus pratcnsis, Sium latifolium, Phalaris, 
Glyccria, Symphytum,, Mentha, Rumece, Allium, etc. 

Prvmet ^ describes Cladochytrium viticolum as the cause 
of the much-discussed Brunisure of vine ; also CI. mori as a 
new disease of the mulberry.^ 

The same authority ^ designates as Pyroctonum sphaericum, a parasite on 
wheat, which has become very abundant in Southern France. 

(2) ZYGOMYCETES. 

Unicellular fungi. Sexual reproduction does not take place by 
the fertilization of an ovum in an oogonium by an antheridium, 

1 Pi'unet, Compt. rend., 1894. - Prunet, Gompt. rend., cxx., 1895, p. 222. 

•■'Prunet, Gompt. rend., 1894, ii., p. 108. 



ZYGOMYCETES. 115 

but by conjugation or union of two cells of the mycelium 
separated oft' from the ends of two hyphae by transverse walls. 
As a result of conjugation, a zygospore is produced, which is 
a resting-spore and corresponds to the oospore of tlie Oomycetes. 
The zygospore puts forth a germ-tube, which becomes a mycelium 
bearing sporangia on sporangiophores. From each sporangium, 
spores, never swarm-spores, are set free, germinate, and pntduce 
a mycelium. Sporangia similar in form to the zygospores may 
be asexually produced on the mycelium. The unicellular and 
much-branched mycelium grows into its substratum, and is 
nourished as a rule saprophytically. The EntomupktJiorcar cause 
important insect-diseases on Muscidae, Cabbage Buttertiies, and 
caterpillars of Trachea innil^crda (the Pine Beauty). 

Another connnon group of the Zygomycetes, the Mucurini, 
penetrate into bruised places in living fruits, and produce decay 
(see p. 180). Some other Zygomycetes are parasitic on fungi 
{Conidioboh(s), some on animals. 

(3) UOMYCETES. 

These fungi possess a one-celled and much-branched mycelium. 
In their vegetative structure they most nearly resemble algae 
like Vauchcria. Keproduction is brought about, asexually by 
means of swarm-spores formed in sporangia (conidia also occur); 
sexually by oospores derived from oogonia and antlieridia. 

There are three families of Oomycetes : Sap/vhyniuccar, Monu- 
blqjharideac and Pcronosjjorcac. Two of these groups contain 
parasitic forms : Saprolrgniaccac [c.;/. Arhi/la prolifcnf, dangerous 
to Fish and Crustaceans) ; and Prmno'^pormc. 

PERONOSPOREAE. 

The greater number of the Peronospon-ai' live as parasites in 
the tissues of higher jjlants, and olitain in»urishment generally by 
means of haustoria. Thf mycelium, in earlier life at least, has no 
dividing septa, and generally grows in tiie intercellular spaces of 
the host-plant, and .sends haustoria into the cells. Reproduction 
is effected asexually l)y formation of swarm-sporcs in sporangia, 
and .sexually by means of oospores. The latter arc produced 
from the fertilization of an ovum in an oogonium liy an aiitheridium 
who.se contents pass thntugh a fertiii/atiou-tulie iieneiraling tlie 



116 PHYCOMYCETES. 

oogonium wall.^ No formation of spermatozoids occurs, as is the 
case in Vaucheria and other groups of algae showing close rela- 
tionship to these fungi. In certain cases the formation of 
swarm-spores in sporangia does not take place, but conidia 
are produced, which germinate directly into a mycelium. 

Preventive measures against the whole group consist in 
destruction (by burying or burning) of diseased and dead parts of 
host-plants which contain the hibernating oospores ; by change of 
crop on infected fields ; and liy treatment with copper reagents 
(see Chap. VI.). 

To the Peronosporeae belong the genera rf/thin)n, Fliyto'pli- 
tliora, Cydoims, Basidiophora, PlaHmopara, Sclcrospora, Uremia and 
Pcronosjwra. 

Pythium. 

The mycelium possesses no haustoria, and grows both between 
the host-cells and inside them. Cross-septa are not present at 
first, but later these may be found at irregular intervals. 
Pythium lives as a parasite in living plants, or as a saprophyte 
on a dead substratum. The conidia are of various forms, and 
either germinate directly into hyphal filaments, or discharge their 
contents into a bladder where zoospores are developed and 
liberated as free-swimming spores with two lateral cilia. The 
oogonia contain only one ovum-cell, which is fertilized by means 
of an antheridial tube applied to the oogonium. The thick- 
walled oogonia on germination produce hyphae or discharge zoo- 
spores. 

Pythium de Baryanum, Hesse ^ (Britain and U. S. America). 
This parasite is injurious to the seedlings of various plants in 
gardens and fields. Some of its commoner hosts are maize, 
clover, mangel, millet, and many species of the Cruciferae ; it has 
also been found on the prothalli of Equisctum and Lycopodinm? 
It may also attack living or dead leaves and tubers of jjotato. 

The sporangia have a lateral beak-like outgrowth, into which 
the plasma passes and divides into biciliate zoospores. The 

^ 111 many species the fertilization-tube remains closed t.<j. PlaHmopara 
viticola. 

-Hesse, Pi/fJiiuiti de Baryanum, Halle, 1874. Atkinson (Cornell Univ. Agric. 
Expt. Stat., Bull. 94, 1895), describes and figures this and other fungi causing 
" Dampiug-off." (Kdit.) 

•' Sadebeck, Nalnrforseh.- Veraammlnng. , 1876. 



I'YTHIU-M. 117 

sporangia, however, may Hrst pass through a reHting period. 
Sexual reproduction consists in the impregnation of an egg-cell 
by means of a fertilization-tube from an antheridium. The 
oospores are formed singly in each oogonium, and are liberated 
only after decay of the oogonium walls and the tissues of the 
host-plant containing them. After a resting period they pro- 
duce a germ-tube, which penetrates into the host-plant and 
becomes a delicate branched colourless intercellular mycelium. 
Hilternation is accomplished both by these oospores and by resting- 
oouidia, which remain amongst the decaying plant-debris on the 
ground. 

Humphrey has observed sickness and death of cucumber 
seedlings as a result of Ft/, de Baryanvm. Wittmack found a 
.species {Fy. Sadrhcckiannm) very destructive on peas and lupines^ 
in various localities ; it has l^een observed freipiently since. 

Py. gracile is ])iua.sitic on algae. 

Py. dictyospermum, Eac. (jceurs in Spirogyra. 

Py. cystosiphon is fouml on species of Lemna. 

Py. intermedium fre(iueiits jnotlialli of vascular cryptuganis. 

Phytophthora. 

The mycelium is at first non-septate though much ])ianched. 
It grows both between and through the host-cells, ami in some 
specjes, (i.fj. FJi. vinnii-ora), has small haustoria. 

The conidiophores branch and produce a large number of conidia 
or sporangia in succession. The first conidia are terminal, but 
are displaced towards one side and thrown oil liy further 
growth of the conidiophore to produce other conidia. 

The sporangia distribute their contents as swarming cells wiiii 
two lateral cilia ; the conidia produce a hy])ha directly. The 
egg-cells are developed one in each oogonium, ami are fertili/.eil 
by an antheridium. The spherical o(»spores germiiiate in spring 
l)y means of a germ-tube. 

Phytophthora omnivora, I)e r.ary- (syn. I'h. /Kyi, \l. Hariig.) 
This is a destructive enemy lo the seedlings of eonifers, and even 
more deadly amongst naturally-sown beech-seedlings. Death of 
the beech is preceded by brown-spotting of stems, cotyleiluns and 

' Vtrrin z. Ii>^f. d. Moorkultur, IS'Jl. 

-' K. Hartig, Zrifsrhri/IJ. FortI n. Jaijd-tvmi.n IS""); also, Und rsui hinfi' n iini 
<l. j'i)rsll,i,Uin. lust. Miinrfitiis, 1880. 



118 



PHYCOMYCETES. 



first leutiets. The disease is spread during summer by coniuia, 
or swarming cells produced from sporangia. The passage through 

winter is effected by means of 
oospores, resulting from fertiliza- 
tion of an ovum in the oogonium 
by a fertilization-tube from an 
antheridium. The intercellular 
mycelium is at first nonseptate, 
later septate, and forms small 
haustoria. Seedlings of other 
plants, besides those already 
mentioned, and also succulents 
(eg. Sempcrvivum and Cactus) 
may be attacked and killed by 
this same fungus. 

This epidemic cannot well be 
combated except l^y methods 
applicable only in the nursery. 
The most eftective method is to 
plant no young seedlings in 
plots which have already been 
diseased, but to reserve such 
plots for older plants to which 
the fungus is not dangerous. If 
the disease be not very general, 
attacked plants may be removed 
singly and destroyed. Since 
moist air is very favouralile 
to distribution of the disease, 
all nettings or trellises should 
be removed from seed-beds 
threatened l)y attack. In dry 
Fio. 2s.-Ph!/ioi>i, thorn o.univora. Cotyledons airy localitics there is Icss- 

to seedlinu's than in 




and primary leaves in early stage of attack ; ■, 

the disease forms brown spots where patches Clanger 

of luyeelium are developed. 4 natm-al size. 



(v. Tubeuf del.) 



moist. 



The fungus often appears- 
in such force that seed-beds of beech or conifers are denuded 
of every plant within a few days, and in the forest beech- 
seedlings may, during damp weather, he completely exterminated 
over ureat areas. 



PHYTUl'HTHOUA. 



119 



Another parasite of conifer seedlings — Fusovia jximsiticnw — 
which S(jme\vhat resembles Pliytoplitliora, is figured and described 
amongst the " Fungi imperfecti." 

Phytophthora infestans, De IJary.^ This parasite was tirst 
observed in Kiudpf in 1845, and has since then become 




Fiij. -j;'. — Cellular tissue from liiseased cotyledon of Beech. The starch-jn-aius 
have been aVjsorbed from the celliirotoplasm which has shrinik away from the 
cell-wall a ; b, l>, intercellular fungal hyphae with very tiny haiistoria ; c, c, 
fertilized oogonia, cucli containing a single oospore. (After H. Ilartig.) 

Fio. •iO.—Plii/toj'hihora otiinivora on the epidermis of a Heech-cotyledon. v. 
Outer wall of "epidermal cell; l>, cuticle; c, hyjihae growinif between cell-wall 
and cuticle, causing the shght protuberance U ; f, spot where a hypha has 
emerged through the cuticle and developed as a sporangiophore/; after the first 
sporangiiuu ha.s reached niatin-ity a seccaid l)egin8 t" fi)rni, <> and A, whereby the 
first is displaced ; L; a stoma fmni which sporangiuphorcs have developed. 
(After R. Hartig.) 

only too will kiKAvn. ll attacks leaves, slioots, and tubers 
of potato and other f^olanaceae, '•.//. the tomato (S. Liicopn-ninim). 
The potato leaves lieconie discoloured, brown-spotti'd, and 
crumpled, especially in damp WLMtlu-r. The spoiangiophores 
(gonidiophores of !)(• I'.ary) issue fnnu the stomatii in 

' !)<• H;iry, Joiinin/ of' Ho/an i/, ISTU, uml Jmininl i>/ lli< /.'oi/it/ A'jrl': Socitli/. 
187H. 



120 



PHYCOMYCETES. 



tufts, and form a white border round the brown parts of 
the leaf; they are monopodially branched and produce terminal 
sporangia (gonidia), which are easily detached. The sporangia 

on germination either pro- 
duce a varying number of 
zoospores, or germinate 
directly like conidia to form 
a mycelium capable of pro- 
ducing new conidia. The 
potato - disease is distin- 
guished from Phytophthora 
omnivora in the absence 
of sexual reproduction by 
oospores.^ It is generally 
assumed that the mycelium 
hibernates in potato-tubers, 
from which the fungus 
recommences to spread in 
spring. Boehm,^ however, 
contests this, and holds the 
hibernation of the fungus 
to be quite unknown, and 
that from the tubers of 

Fig. 31.— Surface of a Beech-seedling with swarm- a disCaSCd plant, either a 

sjjores o, h ; the germ-tubes from tliese penetrate ^ 

between adjacent ejiidermal cells ; c, sporangium with healthy plant Or nOUG at 
zoospores already germinating inside it, d, /; c, a J i: 

germ-tube which lias penetrated directly into an j^H reSUltS. 
epidermal cell ; g, germ-tube which, after growing 

for a time inside a cell, has again made its way out. The PllvtOVhtllOra POtatO- 

(After R. Hartig.) "^ ,. . , 

disease is quite distmct Irom 
(ft) the potato-blight or wet-rot which, according to Boehm, is the 
result of closing up of the lenticels, with a consequent stoppage 
of respiration ; {h) bacteriosis, which will be considered amongst 
the bacterial diseases of plants. 

Lagerheim^ has pointed out that Solanum muricatum 
much cultivated in Ecuador on account of its edible fruit, has 
been for many years subject to attack from Phytophthora 
infestans ; the fruits sicken and rot off before ripening. The 

' Tliis is a well-known point of controversy, for an interesting discussion of 
wliich we would refer to ''Diseases of crops," Worth. G. Smith, 1884. (Edit.) 

-Boehm, Sitzuwjshcr. d. Zool.-hotan. Ges., Vienna, 1892. 

•^ Rivista Ecuatoriana, 1891. 




PHYTUl'HTHOKA. 



121 



i^&55*>s=;-~w. 




Km. 31. — Pli!it'>i>Klhi>,a inftDtaat. Tlio I'otut.) dlMciiHO. A, I'ot.ita loiif with 
liruwii NitotH and whitu {Kitchua uf fuiiKi "ii tliu lower hiili.-. B, (tniiips of rmiidlu- 
]ili<ircH eiiierKiiik' fruin ii Ntoiim cIuku bcniiic a hair of the potato leaf. (', Coiii.llo- 
I'horcM aii<l roiiidia, much eiilarh'L-d. /', Leaf of ]>utato liniih nhrlvclled up and 
I)r<iwi), UH ill the later ntajfeH of tiiu diHi-axe. (v. 'lulieuf del.) 



122 PHYCOMYCETES. 

same author also quotes the disease on Solanum caripcnse 
at Quito, and on Petunia liyhrida at Upsala. 

The potato disease is above all an associate of moist 
weather. In such circumstances, the conidia are produced 
very rapidly and the zoospores readily distribute themselves in 
the moist soil. There is thus greater risk to the potato crops 
on wet soils. 

For wintering, potatoes as healthy as possible should be chosen. 
This is particularly the case if the tubers are required as seed ; 
for the fungus-mycelium spreads from the tuber into the shoot. 
Whole tubers are less liable to infection than those cut or 
broken. Some varieties {e.g. thick-skinned) are less easily 
infected than others ; such should be selected and bred. 

As a preventive measure the leaves may be sprayed with 
Bordeaux mixture, or with a copper carbonate mixture.^ By 
these means conidia and zoospores which alight on the plants 
are killed and their germination prevented. The leaves them- 
selves remain uninjured if the copper compound be used dilute 
enough. These compounds may even be beneficial to the growth 
of the host-plant, as was found by Kumm^ for the vine, and 
Frank and Krtiger^ for the potato. 

Frank and Kriiger found on using a two per cent, copper 
sulphate and lime mixture, in which the copper is known to be 
the potent constituent, that the potato leaves were stronger, their 
chlorophyll-contents greater, their power of assimilation and 
transpiration was increased, the life of the leaf was lengthened, 
and the yield and starch-contents of the tubers were increased. 
They regard the effect of the copper on the leaf as the result of 
a chemotaxic stimulus. 

Jensen recommends disinfection of seed-potatoes by heating 
at 40° C. for four hours. 

Ph. phaseoli, Thaxter, lives in young Ijean-pods and causes 
them to shrivel up. The fungus is as yet incompletely known, 
having only been observed in America where Thaxter * reports 
great destruction of Lima bean {Phaseolvs lunatus) near New 
Haven. 

^ See also § 12. Detailed experiments of this kind are frequently described 
in the magazines relating to agriculture. (Edit.) 
^ Ber. d. deufsch. botan. Ges., 1895, p. 189.' 
■' Ber. d. deiitsch. botan. Ges., 1894, p. 8. 
■'Thaxter, Botanical, Gazette, 1889. 



CYSTOPUS. 



123 



Cystopus (Albugo). 

The mycelium is branched and lirows between the cells of 
living plants, obtaining its nourishment by means of haustoria. 
The conidial cushions rupture the epidermis of the host. The 
conidia or sporangia are smooth-coated, and are produced 
acropetally in chains on short stalks from which they fall off 
separately when ri]"»e. The sporangia germinate and discharge 




Fi(i. :>:;. — i //..i.-yx-.i c.'/i./i".',- ..n i.l.n.t.-- ..i t. ./..-.. ■■■ ,,a.-i„,i.'. Hit.- (unuu.s 

haa caused distortion ami thii'kuiiing ; tlie white poivellanous conidial cushionH 
shew uji distinctly ••}\ the dark background, (v. Tu1>euf jiliot.) 



swarming spores with two uiUH^ual lateral cilia. The egg-cells, 
produced .singly in each oog(jnium, are fertilized I'V an antheridium. 
The thick-walled oospores remain enclosed in the intercelhUar 
spaces of the host-tissue, and on germinating in sj>ring di.^chargc 
swarming spores. 

Cystopus candidus (I'tis.) I.<v. While b'u-i This fungus 



124 



PHYCOMYCETES. 



is very frequent on wild and cultivated Cruciferae throughout 
the whole world, and causes deformation of shoot, leaf, and flower. 




Fig. 3i. — Ci/ntopus candidus. B, Conidiophores isolated from the cushion ; the 
couidia or sporangia are united by intermediate cells. C, Sporangia breaking up 
to form swurm-spores. D, Swarm-spores escaping. E, Swarm-.spores in motile 
condition. /', Swarm-spores come to rest and germinating. G, Two germ-tubes 
entering a stoma of Lcpidiam sativum; the stoma is shown from the inside, so 
that the .spores from which the germ-tubes arise are on the outer surface and 
unseen. (After De Bary.) 




Fio. 35. — Flower of Radish (Jio.phanas saticas) hypertruphied by Cystojuis 
cd.iididi's. The much-enlarged ovary stands out in the centre. The anthers are 
If af -like ; the petals are much enlarged and hang downwards ; the sepals are 
somewhat enlarged. (Specimen from Botanical Museum of Erlangen, and 
photographed by Dr. Bnnis.) 

The couidial cushions form thick white stripes with a porcellaneous 
appearance, by which they are easily distinguislied from the 
cushions of Peronospora parasitica often present on the same plant. 



CYSTOPIS. 



125 



Besides conidia, spherical oospores may also We present ; these 
are generally })r(MhR'ed on the stems of the host-plant, hut also 
on Hower-stalks and ovary-walls. 

The spherical conidia arise in simple chains on short coni- 
diopliores, and are loosely connected liy tiny intermediate cells. 
The conidial cushions rupture the epidermis and the ripe conidia 
fall oft" to produce biciliate swarming cells (Fig. 34), These 
give rise to germ-tubes which enter the stonuita of seedlings and 




Fio. 36.— Flower of Radib)) hyiiertrophied by Ci/slopi's ainJiili'ii. The white 
BWoUen conidial cu.sliioDH occupy the enlarged petals, sepals iiml ovaiius. (1>|-. 
Bruns' phot.) 



develop lo intercellulai' niycclia, tine short lateral twigs of 
which pierce the wall of the host-cells and liccomi' litth- 
spherical haustoria. 

The oogoniu arise as thick-wallrd spherical swellings on the 
mycelium. The antheridium, after applying itself to tlie oogonium, 
widens and pr(»jects a thie fertilization-tuhe throiigli the wall to 
the egg-cell. After fertilization is ellected, the egg-cell is enclnsed 
in a firm uneven mend)rane, and hibernates inside the oogonium. 
In spring the jdasma of the oospore forms numeroii.s biciliati' 



126 



PHYCOMYCETES. 



swarm-spores which escape from the enclosing coats and germinate 

on seedling plants. 

De Bary ^ found germ-tubes of 
Cysfopus entering all the stomata of 
Lcpidiuin sativum and of Capsdla, 
but they only developed further if 
the part attacked were the cotyledons. 

Magnus ^ observed an infection of 
Raphanus Baphanistrum in which the 
unopened buds were infected by swarm- 
spores. Oogonia may be found in the 
flowers of this same plant, whereas 
conidia alone only are present in 
Ccqjsclla. 

White rust is most commonly 
observed on CapscUa, causing slight 
local swelling or marked hypertrophy. 
It is also found to injure radish 
{Bap)hcmus sativus), hoi-se radish 
{Cochlearia armoracia), cress (Lepidium 
mtivum), species of cabbage and 
turnip (Brassica Napus, B. nigra, B. 
Bictpa, B. oleracea), wall- flower (Cheir- 
anthus Cheiri), water cress {Nasturtiwni 
amphihium, etc.), caper-plant (Capparis 
spinosa), and other wild and culti- 
vated plants belonging to, or closely 
allied to the Cruciferae. 

Wakker ^ investigated the changes 
Ijrought about on a number of Cruci- 
ferae l:iy Cijstop>us. Some plants showed 
little or no deformation or anatomical 
alteration, others showed much. While 
the anatomical changes in the various 
species examined agreed in general, 
yet some showed a predominant or 
exclusive formation of conidia, others of oospores. The changes 




Fig. 37. — Cystopus poriulacae, D. C. 
'Ill, mycelivim ; .;', basidia ; c, spores 
with intermediate cells. (After 
Tulasiie.) 



' Morphology awl Biology of the Fungi. Englisli Edition. 
~ Abhand, d. hofan. Vereinn d. Prov. Brandenburg, xxxv. 
•' Pringsheini' s Jahrbuch, 1892. 





CYSTOPUS, 127 

observed on Capsdla may be sunnuarizfd here : the fungus 

attacks all parts above ground, and causes enlargement of 

parenchymatous cells ; it forms only 

conidia ; formation of chlorophyll is 

increased ; the formation of interfasci- ^ 

cular cambium is diminished or altogether 

suppressed ; the intrafascicular cambium 

retains its activity longer ; accessory 

vascular bundles make their appearance ; cyVolmtpTruaaiac^'tA^^^^ 

no differentiation of tissue takes place 

in the ovary wall, the secondary vessels remain incomplete, 

and the eml)ryo diies u|). 

C. portulacae, D. C. On Portalaca oleracea and P. saticn (T. S. Anierira). 

C. tragopogonis, Pers.^ (C. spinulosus) (Britain and U. S. America). On 
Conqjositae, e.g. Chamomilla, Achillea, Cirsium, Scorzonera, etc. The markings 
on the spore-coat take the form of a double net-work. 

C. convolvulacearum, Otth. (C ipomoeue-panduranae, Farl.). On Con- 
i-olvulact'cw. (iialsted - gives this as one of the causes of rot in sweet ])Otato 
in America.) 

C. bliti (Biv.-Bern.). On species of Amarantaceae (U. S. America). 

C. lepigoni, de Bary. On Sperfjularia (Britain), 

Basidiophora. 

The non-septate mycelium inhiibils intercellular spaces of 
living plants, and is nourished by small haustoria. The conidio- 
phores issue in tufts from the stomata, and have a characteristic 
f(»rm ; they are unbranched with club-shai)ed ends, from which 
arise several sterigma-like conidiophores with almost spherical 
conidia. The conidia or sporangia are produced in large numliers, 
and on germination discharge numerous zoosjjores with two 
lateral cilia. The oospores are formed singly in the oogonia, and 
appi-ar ,is v<-ll(i\visli-brn\vu bodies in tlie interior of the plant. 

Basidiophora entospora, Koze and Cornu. On Eriijcrun cana- 
ilaisc, Aster, Solidafju, etc. (IJritain and V. S. America). 

Plasmopara. 

The mycelium is richly l)r!ine]ied and grt)\vs iiiteri-eHular, 
nourished by little l)utton-sha])i'd hausturia. The (•((niiUnphiires 

' MagnuM, lii r. <l. dtntxrh. hotait. (Itt., ISD.S. 
^Z'l/'«hri/t/. rjlanzntkiaukhitin, ISO"), |). :W8. 



128 



PHYCOMYCETES. 



arise in tufts froin the stomata ; they are branched in various 
ways, and from each branchlet a single conidium is abjointed. 
The contents of the conidia emerge as swarming cells with two 
lateral cilia, or as vesicles which emit a germ-tube. The egg-cells 
occur singly in each oogonium, and are fertilized by an antheridiuni. 
The oospores remain long enclosed in the thick-walled oogonium. 




Fio. 39. — Flaxmoparo. viticola. Vine leaf with white spots on the under surface, 
from which tufts of conidiophores emerge, (v. Tubeuf del.) 

Plasmopara nivea (linger). (Britain and U. S. America). 
Inflicts great injury on various wild and cultivated Umbelliferae, 
e.g. carrot (Daucus Carota), parsley {Pctroselinum sativum), chervil 
(A'/ithriscus Cerefolium). 

Plasmopara viticola, Berk.^ The Downy or False Mildew of 

^ JJiljliography. De Bary, Annal. d. sci. nat., 1863. Viala, Die Fihe d. 
Weiiisfockes ; with good bibliography. Prillieux, Annal. de. I'instit. nat. 
agronomicjue, 1881. Cornu, Le Peronospora des Vignes, Paris, 1882. Sajo, 



PLASMOPARA. 



129 



the A'ine. This parasite was introduced into Europe from 
America.^ It makes its appearance in early summer as white 
patches on the under surfaces of leaves, sometimes also on stalks 
and fruit. In the course of the summer the leaves show brown 
spots and dry up. 

The white patches consist of tufts of branched conidiophores, 
from which ovoid conidia are abjointed. These on germiua- 




Fio. 40. — PtasmojK'ra viticola. Conidiophores, much eiihirged. (v. Tiiboiif ik-l.) 



tion in raiii-drnps di,schai-y;c six to eight swarming cells from 
which germ-tubes grow into the epidermis of the host-plant ; 
thus the disease spreads rapidly duiing moist weather and a 

I'trouoxjiora i-iticola, 1890. Magmi.s, Wiltmark's (,'arftiiziit, iSSli. Sciil.iKi . 
liejiorl of U.S. D^]lt. of Aiiriniitiiri- for I88(j, pp. (IG-lOri ; tliis lontaiiis an 
excellent account of this niiMew. Aitiilcs on tliis siilpjtrt ilialinj; witli ivnu-tlial 
nieaMures arc fie<nuiitly piil)li.-lR<l in tlie l'..'>;. Anur. I»eii:ii tniint ii'iiorts and 
ItulietinH, in tlic Imlktiiis from oxpei iniental stations, ami in tin- lioitiLiiltural 
jounuii.s, 

' .Seymour and Fallow give it as occurint{ on every American spicies of I'itin. 



1 30 PHYCOMYCETES. 

wet season is very favourable to it. The mycelium is non- 
septate and spreads through the intercellular spaces of the host, 
nourished by button-like haustoria sunk into the host-cells. 
The antheridium comes into contact with the oogonium by a 
fertilization tube, which, however, remains closed. The oospores 
hibernate in leaves and fruit. 

Prevention} Ammoniacal copper carbonate solution, eau 
celeste, or Bordeaux mixture, prepared as described on p. 69, 
may be used. The tirst-named solution seems least liable to 
injure the foliage ; the others must, on this account, be used 
with care. The first application is made about the time the 




Fig. 41. — Plasmopara pygmaea on Anemoiie nemorosa. ('onidiophores emerging 
from a stoma. Intercellular mycelium with baustoria. (v. Tubeuf del.) 

berries are well formed, and the sprayings are repeated every 
twelve to fifteen days, or oftener if there are heavy rains, till the 
grapes begin to colour. It must, however, be remembered that 
sprayings of this kind do not reach the mycelium inside the leaf, 
but only act superficially, killing any developing conidiophores 
or conidia which may alight on the leaf. These fungicides are, 
at the same time, remedies for powdery mildew (Uncinula). 

" Sulphuring" as a remedy for this and the powdery mildew 
has been recommended by continental writers.^ The burning 
of all diseased vine-leaves is strongly recommended. Attention 
also should be given to the cultivation of disease-proof varieties.^ 

PI. pygmaea (Uuger). On Ranunculaceae (Britain and U.S. America). 
PI. pusilla (De Baiy). On Geraniums. 

^Galloway, "Fungous diseases of the grape and their treatment," U.S. 
Dept. of Aijric, Farmers' Bulletin, No. 4, 1881. 

-Oesterr. Weinbaukongress, 1891. Reported in Oest. landwirth. Wochenhlatt, 
X., 1881. 

^Millardet (see Chap, vi.) 



PLASMOPARA. 



131 



PI. viburni, Peck. Ou Vihuraum (U.S. America). 

PI. densa (Rabli.). On Scrophularineae (Britain). 

PI. ribicola (Schroet.). On Itihes ruhrum (U.S. America). 

PI. epilobii (Rabh.). On Epilohium paluatre, and E. parvifoUum. 

PI. obducens (Schroet.). On cotyledons of Impatiens (U.S. America). 

PI. geranii (Peck.). On Geraniums in America. 

PI. Halstedii, Berl. and de Toni. On Silphiuui, Rudbeckia, Helianthus, 
and many other American Compositae. 



Sclerospora. 

Mycelium inteicellular in living plant-tissue.s, and deriving 
nourishment by means of haustoria. The conidiophores are 
thick, short, and divide at their apices into short broad Ijranches, 
from each of which a single conidium is abjointed. The conidia 
in germinating discharge swarming cells. One oospore is formed 
in each oogonium. 

Sclerospora graminicola (Sace.) lives in several species of 
Stfd.ria (^r.S. America). 

Bremia. 

Mycelium intercellular in higher plants, and nourished by 
little button-like haustoria. The conidiophores are branched, 
and at their apical ends 
become swollen in a char- 
acteristic manner, so as to 
resemble a hand held cup- 
like with the fingers project- 
ing separately u[iwards, like 
the tentacles of Hydra. The 
conidia are abjointed singly 
from the tentacle-like pro- 
cesses, and germinate, emit- 
ting a germ-tube through a 
<letinite thin spot in their 
coat. Oospores originate 
singly in oogonia. 

Bremia lactucae, lieg. 

( I'l riniiispiiiii ijii injl iDiuJiinni^ 
l»erk.^) (liritain and U.S. Aiut-rica). Tlie richly-branched cnnidio- 
phures appear singly mi atLa<-ked parts of jilants. This fungus 
' Coniu, C'ojnjil. fiiil., \b~s. 




Fid. 4:;.— /i,t)(i,a Utctucu. (v. Tube il .lul.) 



132 PHYCOMYCETES. 

may cause considerable damage to the lettuce {Lactnca scdiva), 
this being especially the case in France. The parasite is most 
dangerous in forcing-houses during winter or early spring, and 
spreads rapidly, favoured by the damp atmosphere. The young 
diseased plants are stunted, and take on a pale colour. Early 
removal and destruction of diseased plants is to be recommended; 
also abandonment for lettuce-cultivation of infected houses or 
frames. 

In addition to lettuce, this fungus attacks a number of 
Compositae, e.g. Cineraria, Sonchus, etc. 

Peronospora. 

The mycelium is intercellular in living plants. The haustoria 
may be simple, button-shaped, or thread-like, or may branch 
inside the host-cell. The long and much-branched conidiophores 
produce conidia singly at the ends of their branches. The 
conidia produce a germ-tube. The oospores are brown-coated 
and are formed singly in the oogonia ; they germinate in spring. 

Peronospora Schachtii, Fuck.^ is injurious to the inner 
leaves of sugar beet and mangold {Beta, vulgaris), while young 
seedlings are killed by it. The mycelium hibernates in the 
roots ; as yet oospores have not been found. 

P. effusa (Grev.) This causes injury to spinach (Sjnnacia) 
oleracea) and other Chenopodiaceae (Britain and U.S. America). 

P. Schleideni, Ung. Kills the leaves of cultivated and wild 
species of onion (Alliurn) (Britain and U.S. America). 

P. dipsaci, Tul. Injures stems and leaves of Dijpsacus sylvcstcr 
and D. Fidlonum. 

P knautiae, Fuck., of Knamtia. and Scahiosa, is probably identi- 
cal witli last. 

P. viciae (Berk.) (Britain and U.S. America). A dangerous 
species to many Papilionaceae (especially peas, beans, tares, 
lentils, etc.), often causing great damage to field crops. In 
recent years the new fodder-plant Lathyrus sylvcstris has been 
frequently attacked.^ 

P. trifoliorum, De Bary ^ (Britain and U.S. America). Dis- 
tinguished from the preceding form by its irregularly marked 

^ Kiihn, Botan. Zeitung, 1873. 

- Zcitschrift f. Pflanzenhrankheiten, ii., p. 225 and 283. 

^Siuitli, DUta^tti of Crops, London, 1884. 



PEUONOSPORA. 



133 



oospore-coat (oospores of P. viciae have a coat with a regular net- 
work). It occurs on stems, leaves, and petioles of clovers, lucerne 
and other Papilionaceae, often with disastrous effect. 

P. sparsa, Berk. (Britain and U.S. America). This ])arasite 
on the rose was first observed in England. It injures indoor 
roses, causing a fall uf the leaf, preceded by the appearance of 
lilac-coloured spots which, on the underside of the leaf, are closely 
Ijeset with a white coating of conidiophores.^ 




f'li;. 43. — Ptronnnjioi-a ricici. Coiiididlihorcs :iiid coiiidia. (v. TillxMif del.) 



P. arborescens (BLrk.). Un leaves and shoots of wild and 
cultivated popi)ies : especially injurious to seedlings vf garden 
species. 

P. parasitica (Ters.) (Britain and I'.S. America). Thi.s j. re- 
duces greater or less deformatitm of attacked stems of many wild 
and cultivated Cruciferae. Amongst cultivated plants the most 
liable to injury are the varieties of turnips and cabbage, radish, 
rape, cress, vvallHower, also the mignonette. It is generally found 
along witii ('i/.sfiq)iis anufufus on shepherd's purse {Ct(/)sr//ti). 

P. cytisi, Kostr.,- attacks seedlings of laburnum in Denmark, 
causing death in a few days. The leaves become bniwii spotted, 

^ ZeitHiltri/l /. /'.k-rnid., ii., )•. '.IHti, (ilescripi inn ,,\ ;iUa.k in Sik-.-^iii.) 
- Kostrup, ZfilHi-hri/t f. I'jhiir.' nh'anklniiti n, IS'.CJ. 
Mugnu.s, llriliriiiia, IS'J'J. 



134 PHYCOMYCETES. 

and branched conidiophores with light-brown conidia arise from 
their underside. Numerous oospores may be found in the leaves. 
Kirchner ^ observed the disease on leaves of four-year-old plants, 
yet without injurious effects. 

The following are other British or American species : 

Peronospora ficariae, Tnl. On Ranuncithts, Mi/osra'us, etc. 

P. corydalis, I)e By. On Corydalis and Dicentra. 

P. violae, De By. On Viola tricolor. 

P. arenariae var. macrospora, Far]. On Stlene. 

P. alsinearum, Gasp. On Cerastium. 

P. claytoniae, Farl. On Claytonia. 

P. lini, Sclii'oet. On Linum. 

P. potentillae, De By. On Rosaceae e.g. Geum, Fragaria, and Potentilla. 

P. Arthuri, Farl. On Oenothera. 





Fio. 44. — Peronospora alsinearum. Sexual org-ans. o, Yoimg condition ; h, for- 
mation of ovum and fertilization-tube ; c, after fertilization, (periplasm some- 
what contracted by preparation, and the fertilization-tube unusually thick) ; 
n, antheridlum ; o, oogonium, x 350. (After De Bary.) 

P. leptosperma, De By. On Compositae e.g. Artemisia. 

P. Candida, Fuck. On Androsace and other Primulaceae. 

P. cynoglossi, Bnrrill. On Cynoglossum. 

P. myosotidis, De By. On Myosotis and EcJunospermvm. 

P. sordida, Berk. On Nicotiana and Scrophularia. 

P. hyoscyami, D. By. On Tobacco in America and Australia {Gard. 
Chron. ix.). 

P. linariae, Fckl. On Linaria. 

P. grisea, Ung. On Veronica. 

P. lophanti, Farl. On Lophanthus. 

P. alta, Fckk On Plantago. 

P. (Plasmopara) cubensis is reported '■^ as causing an extensive and 
destructive dise;ise of cucumbers (Cucumis and Cucurbiia). 

P. (Plasmopara) australis, Sjjeg. On Echinocystis lohata and Sicyos 
angidatus in America. 

' Kirchner, Zeit.schri/t f. PJlanzenkrankheiten, 1892. 
-Humphrey, Report of the. Mans. Af/ric. Exper. Stat., 1890-92. 
Massee, Gardener's Chronicle, Vol. xvii., p. 65G, 1895. 



HIGHER FUNGI. 135 

P. oxybaphi, Ell. and Kell. On various Nyctaginaceae. 
P. polygoni, Thiiin. On Polygonum. 
P. euphorbiae, Fuck. Ou Euphorbia. 
P. urticae (Lib.). On Urticaceae. 
P. elliptica causes death of lilies.' 

B. Higher Fuxgi (Mycomycetes). 

The higher fungi are distinguished from the lower in possessing 
a mycelium, which, from the first, is divided by means of cross- 
septu. The mycelium of the lower fungi, though often much 
branched, remains unicellular till cross-septa arise on formation of 
reproductive organs or in the older stages of the fungus.- In 
higher fungi, septation begins with the first appearance of 
mycelium and extends acropetally, growth in length proceeding 
from the terminal cell. Sexual organs are without doubt present 
in the lower fungi, but amongst the higher forms, Brefeld believes 
that the .sexual act no longer exists. On the other hand, certain 
organs, found especially in the lichens, have been regarded as 
sexual. 

Dangeard regards the union of cell-nuclei as a sexual act, 
and assumes its existence in the asci and basidia of higher 
fungi. His more recent investigations on the nuclei of fungi, 
combined with those of Pairault and liaciborski, have laid the 
way to a new systematic arrangement.^ Just as amongst the 
lower fungi the cell produced l)y a sexual act contains a nucleu.>^ 
derived from the fusion of two nuclei of distinct origin, so amongst 
the higher fungi one also finds cell-nuclei derived from copulation. 
The investigations of Dangeard, Ilosen, AVager, I'airault, and 
Raciborski, lead to the conclusion that:* "a stage may be 
found amongst higher, as well as lower fungi, in which two 
cell-nuclei of one cell copulate. The cells known as oospores 
of the (fomi/cdcfi, zygospores of the AirJiimi/crtm and Zi/t/omi/rrff>i, 
chlainydospores of tlu; Ustilaiiiiuw, and teleutospores of the 

'Smith, Diseane of Lilies, 1888. 

-Zopf. Dir /'ilif, lS90;an(l lirilraij' -.. Phyniol. u. morphol. ulrdirtr (fr<inii!iiitiii. 
Heft III., IH'J.S. 

•* DiiiigcJird. " liuclificlics Hiir lii ri'prod. scxiu-ll d. iliiiinpiK'iuiiis " /,« 
liotanisfr, \H\i3. I'air.iidt mid Kacihur.ski. " Siii- lis iKiyiiux di.s Urudinccs" 
Joitr. lit liotnuique, iSJI.'t. 

* RttcihoiHki. Flora (injiinzuniixlKiuil], IS*.)."!, p. 4;V.). ('oiiipiiri- ul.so : Stni.-*- 
l)urf{fr. " UcheiperiodiHclu'Ki'duktioii d. ('liiiiiiui.s(iiiitii/;dd iiii Kiitwickfhmgsjiiuij; 
d. OiniiiiiHiiieii," liiol. Cmfrn/hlntt, 1S{»4, p. .S(i'_'. W'aj^'ci. " Nm Kiir ili\ ision in 
the HyiiiciioiiiyceteH," AhiuUm o/ Hutuiiy, ISlt.J, p. -I'.Mi. 



136 • ASCOMYCETES. 

Uredincac, we designate amongst the Ascomycetes, as asci, and 
amongst the Protomyceics and Basidiomycetcs as basidia. This cell, 
a homologue of the primary embryo-cell of the Archegoniatae 
and Emhryonatac, indicates a turning-point in the development, 
the beginning of a new generation. It either becomes a resting- 
spore, as in Phycomycetes, Ustilagineae, Uredineae (exclusive of 
Colcos])orium and Chrysomyxa), or divides at once to form free 
endospores as in the Ascomycetes, and exospores in the Protomycetes 
and Basidiomycetcs. From these facts the distinction between 
basidiospores and conidia, asci and sporangia, teleutospores and 
chlamydospores, has been for the first time distinctly proved." 

ASCOMYCETES. 

The Ascomycetes show relationship to the higher fungi in the 
possession of a septate mycelium. Their spores are produced in 
cylindrical sacs called asci, whence the name Ascomycetes is 
given to the group. 

The primary imcleus of each ascus results from the copulation 
of two nuclei of distinct origin and with no relationship to each 
other. From the division of this nucleus and its daughter- 
nuclei, there are produced a number of free endospores varying 
according to the species. These may remain unicellular or, by 
means of septa, become many-celled bodies from each of whose 
individual cells germ-tubes may develop. It is advisable to give 
the name spore to each cell-group which develops from one 
nucleus.^ 

Ascospores are never zoospores, but are always quiescent and 
possess a cell-membrane. They are generally forcibly expelled 
from the asci. The asci originate either directly from the my- 
celium, as in the Saccharomycetes and some Exoasceae,^ or a part 
of the mycelium becomes differentiated into an ascogenous layer. 
The ascogenous layer may include only a few cells, as in the 
lower forms, or it may be a complex tissue. In the higher forms 
the aggregations of asci are enclosed in coverings, but the asco- 
genous layer takes no part in the formation of the enclosures 
nor of the accessory organs known as paraphyses and periphyses. 

1 De Bary held that each individual cell capable of germination is a spore, the 
single nuUti-cellnlar spores he designated sporidesmia. 

-Hansen, Cantralhl. f. Bacteriolo<jie und Parasitenkunde, 1893. 
Sadebeck, Die parasitischen Exoasceen, 1893. 



ASCOMYCETES. 137 

This ascogenous layer has been named the ascogonium, and it 
was at one time generally believed that it arose from a female 
cell, the homologue of the oospore of lower fungi ; a hypha 
which applied itself to the ascogonium was regarded as a male 
or antheridial organ, and called a pollinodium. In other cases, 
a thread-like hypha, which proceeded from the ascogonium, was 
called a trichogyne ; it was believed to be fertilized by means 
of certain very small cells (spermatia) produced in special 
structures, the spermogonia. These spermatia, though known 
for a long time, have only recently been made to germinate, and 
that only in nutritive solutions. The significance of the pol- 
linodium as a male organ is not necessarily wrong, though it 
may be a functionless structure, such as we already know 
antheridia of many of the Phycomycetes to be. So also we may 
still consider the spermatia as sexual bodies, even though they 
germinate like spores, for* their never-failing production before 
aecidia would seem to suggest some relationship. In the 
following pages we will speak of these little spores, sometimes as 
spermatia, sometimes as conidia. 

Reproduction of Ascomycetes may also take place by eonidia 
and chlamydospores, capable of germination to form mycelia. 

Amongst the Ascomycetes one finds the higher stages of de- 
velopment accompanied by an almost complete enclosure of the 
aggregations of asci. The asci of the Saccharomycetes originate at 
any spot whatever between the mycelial threads; in fii//iiiioa.'icus 
one finds a loose web of mycelium forming a covering to the asci ; 
in higher forms an enclosure (sporocarp) of definite shape is 
developed. On this account, the forms which do not produi-e 
sporocarps are classed together as Gymnoasci, the sporocarpous 
forms as Carpoasci. Amongst the latter, the sporocarp of the 
higher forms possesses a definite opening from which the spores are 
emitted after liberation from the asci ; certain lower forms (l*eri- 
sporiaceae) have indeed s])orocarps, but these po.ssess no opening, 
and it is only after they have rupturetl or decayed tliat llif 
spores are set free. 

A. (iVMNOAHCI. 

{Ascomi/cetea without Sporocarpx.) 
The asci are produced over the whole mycrlium, or from a 
Hi»ecial asc(jgenous part of it, and are never enclosed in a spom- 
carji. 



1 38 ASCOMYOETES. 

The genera placed in the Gymnoasci are : Dipodascus, Ere- 
masmis, Ascoidea, Protomyces, Tainhrina, Exoo-scus, MagnusicUa^ 
Saccharomyccs, MoJiospora, Endomyces, Podocapsa, Ercmotliecium , 
Oleina, Bargellinia, Ascodesmus, Gymnoascus, Ctenomyces. 

Protomyces, Taphrina, Exoascus, Magmisiella, are true parasites 
of higher plants: Endomyces, Ascoidea, and Saccharomyccs occur in 
the flux diseases of trees ; the others are saprophytes, or 
parasites on fungi (Podocapsa). 

Protomyces.i 

The genus Protomyces possesses a septate mycelium, and 
in this shows relationship with the higher fungi. It is also 
distinguished by the formation of sporangia (asci), which are 
produced in an intercalary manner like tlie chlamydospores of 
the Ustilagineae. Conidia are also developed, which sprout 
yeast-like and conjugate like those of many Ustilagineae. 
Thus Protomyces stands in one direction between the sporangi- 
ferous lower fungi and the Ascomycetes, and in another between 
the Ascomycetes and the non-sporangiferous Ustilagineae. 
Brefeld allocates them with the Ascoidea and Theleboleae to 
his intermediate group the Hemiasci. De Bary {Com^xiratire 
Morphology of the Fungi) agrees with Fisch in placing them 
])etween the Chytridiaceae and Ustilagineae, but in his "Peitrdgen" 
considers them as the simplest forms of Ascomycetes, 

In any case they do not show very close relationship with 
any group. 

Protomyces macrosporus, Ung. (Britain). This parasite lives 
by means of an intercellular septate mycelium in leaves and stems 
of Umbelliferae, especially Aegopodium Podagraria, Chacroyhyllnm 
Idrsut%im, Hcracleum SphondyVmm, etc. It also causes injury to 
cultivated carrots. 

The disease shows itself externally as pustule-like swellings 
on the organs attacked. These are caused, as shown in the 
figures, by a mycelium which pierces the epidermis, and, after 

^ De Bary, Untcrsuchunrien ub. d. Brandpihe n. d. du7xh de verursachten 
Krankhfiten d. Pflanzen. Berlin, 1853. 

De Bary n. Woronin, Bfifriiije z. Morj)h. u. Phydol. d. Pihe, I. Bel., 1864. 

Fiscli, Beitri'uje z. Kenntniss d. Chytridiacctn, 1884, p. 41. 

Brefeld, IJefepilze, p. 176. 

B. Meyer, " Uiitersucliungen lib. die Entwickeluiig einig. parasit. Pilze bei 
saprophyt. Ernahrung. " Inaugural Dissertation, 1888. 



PROTOMYCES. 



139 



distributing itself through the intercellular spaces, stimulates the 
parenchyma-cells of the host to growth and cell-division. The 




Fig. 45. — Protomyce^ maerotporus oa leaf-stilk of AefiopiHlium Fo'la{iraria. 
A, Mycelium and .'tponingium in the ti.ss\ie under the epidermis. B, Sporangia 
in stages of development, (v. Tuljcuf del.) 

latter is a secondary process and consists (see Fig. 9) in the 
formation of exceedingly delicate membranes inside the original 




Flii. 4»!. — Prolomyeet miieroijtorut. Suction of i>etiolo of Atijopodiutu with two 
HWolUn^ containing; spores. Secondary cell-wullM liiivu l)vcn formed, and h 
ciilluiicliyinii region lies liotween tlie two 8Wullln){H. (v. Tu>K)uf del.) 



cells (tf the paiciichyiiia, so thai they become divided into 
younger cells rich in jiioidplusm and eaeli '^bowing a distinct 



140 



ASCOMYCETES. 



cell-nucleus. This tissue so formed may be compared to the 
nutritive tissue formed secondarily from parenchyma as a result 
of other fungoid diseases, e.g. in violas attacked by Urocystis 
violac. If the formation of sporangia ensues in parts which 
would normally become collenchyma, the tissues there remain 
thin-walled. 

The sporangia of Protomyccs, according to De Bary/ begin to 
develop as soon as the young leaves and shoots of the host- 
plants emerge above the ground in spring. The sporangia first 




Fig. 47. — Protomyces macrosporus. Section through swollen leaf-stalk of Aego- 
podium. Towards the right end the cells are normal, elsewhere they are, under 
the influence of the mycelium, much enlarged and sepondarily divided ; two 
roundish sporangia lie in this tissue, (v. Tubeuf del.) 



appear as series of swellings on the hyphae and are easily 
detected in deformed plants as large thick-walled bodies lying 
in the intercellular spaces. They are liberated on decay of the 
host-plant, and in spring the contents swell up so as to rupture 
the thick outer wall, and the endosporium emerges as a vesicle 
or sporangium into which the protoplasmic contents pass to 
form numerous rod-shaped spores. The spores are ultimately 
expelled with considerable force, and, after conjugating in couples, 
they send forth a germ-tube which penetrates again into the 
tissues of the host-plant. 

' Ue Bary, Beitriuje z. Morph. n. Pliy^iol. d. Pilze, also Botan. Zeitnng, 1874. 



PROTOMYCES. 141 

In nutritive solutions germination does not take place in this 
way, but is replaced by a yeasi-like sprouting of the sporangial 
spores without disjunction of the sprout-cells.^ 

According to Meyer, these sprout-cells produce elongated 
hypha-like cells with which, however, he did not succeed in 
infecting a new host-plant. He also found that spore-conjuga- 
tion takes place better in water than in nutritive solutions. 

Pr. fuscus, Pk., occurs on Anemone in America. 

Pr. pachydermus,Thiim., occurs on Compositae esp. Taraxacum. 

Pr. radicicolus, Zopf.- A form similar to P. macro-'iporufi, 
but furnished with coiled haustoria. It lives intercellular in roots 
and kills the cells, without, however, causing external hypertrophy. 
Zopf found it in roots of Stiftia Chrysantha and Achillea 
chjiJcolata in the botanic garden of Halle, but the plants were 
not killed, because their roots were not all attacked.^ 



Endomyces. 

The usci contain four spures which do not produce conidia. 
The sterile hyphae give rise to chlamydospores and an oidial 
form of spore. 

Eiidomyecs dccipicns lives as a parasite on sporophores of 
Agaric us mellcus. 

According to Ludwig, species of Endomyces have much 
to do with the slime-tiux of trees, which contain in addi- 
tion other forms of Gymnoasci, c.r/. Sacrliaromyccs Ludu-iyii, 
Ascoidecc ruhcsccns, etc. "VVe shall here devote some space to 
the general consideration of the slime-Hux of living stems. 
This phencnnenon remained uninvestigated until Ludwig took it 
up and directed attention to it. He found several species of 
considerable systematic interest, the pathological effects of which, 
liowever, re([uire further investigation. 

' IJrcfeM, SrhimmelpUze, Heft ix., 1891. 

-Zopf, Zitr Kriuidiixs d. lufe.rtionxkrankh. nieilerer Thiere n. Pflair.vn, 18SS. 

^ Saccanlo, who ranks the Protomycetes along witli the Cliytridiaceae, inchules 
a large number of species. Magnus places Protomycen (''.) jilicinnx, Niessl. ( IVr- 
hditil. de.x internal. Iiulan. Kon</r(ss in Genoa, lSi)2) in tlie neighhourhood of 
tlie I'liyconiycetes ; it, liowever, possesses a se])tate mycelium and styK)spore8 
which are enclosed in a cr)at so that they recall spores of tlie Uredineae, lionce 
Magnus named it UraliiKiiixin jilirina on /'/it i/oj)/) ris nili/nris. Tliis species 
must not Ijc confuseil witli the .species of L'rulo occurring on l'/ii<joj>tvriK 
Dri/oj)ltriM, Cyitopttria fniijilix, and Scoloiicndrium ojjicinah 



142 ASCOMYCETES. 

The Slime- or Mucilage-flux of Trees. 

This is a very common phenomenon in our avenues, parks, 
and forests. It can be observed during the period of vegetation 
on several species of trees, particularly on spots wounded by 
removal of branches, by frost rupture, or by some other cause. 
The wound may, however, be so grown over or occluded that 
at first sight the slime appears to flow from the uninjured 
bark. These slime-fluxes are very common on dead branch- 
snags and in places affected with sun-stroke or frost- wounds ; 
while I have frequently found them on dead tree-stools 
and on wooden water-pipes where the water trickled from 
some fissure. It is thus probable that they are always 
produced on the site of some wound, although Ludwig, 
without giving any details, says that there may be no previous 
injury. I have never observed any case where a tree with a 
slime-outflow became sickly and died, and the cases of death 
recorded by Ludwig are probably due to some other cause. 
Ludwig, however, says decidedly that the white slime-flux on oak, 
as well as the browm flux of apple, horse-chestnut, and 
others, are really parasitic phenomena. I must say, however, 
that I have carefully examined the occluding tissues on frost- 
cracks showing slime-flux, and found them quite healthy. 

The white slime-flux of the oak.^ 

According to Ludwig, the white slime-flux of the oak and 
other species of trees takes place during moist weather, and 
from June to September. It flows from branch-scars, former 
frost-ruptures, and other wounded places ; also from apparentl}' 
uninjured bark. Ludwig believes that such wounds are infected 
by the agency of insects, particularly hornets ; that the disease 
spreads through the bark and breaks out in various places. On 
such spots the edges of the wound are alternately occluded 
and killed again, so that a flux-wound may come in course of 
time to resemble a "canker-spot." Large areas of the bark die off, 
and the death of the wood frequently follows. 

1 Ludwig: (1) " Ueber Alkoholgahrung ii. fSchleimfluss lebender B;iume ii. deren 
Urheber. " Ber. d. deutsch botan. (?es., 1886. (2) " Uelier profuse (4ummose d. 
Eichen u. welter. Mittli. iib. Alkoholgahrung u. Schleimfluss lebender Baume. " 
Gentrhl. f. Bakt. u. Parcmlenkwide, 1890. (.S) Lehrbuch, 1892. (4) Forst.-nalur- 
iviss. Zeitschr., August, 1894. 



ENDOMYCES, 143 

The slhne-flux is the product of an alcoholic fermentation and 
has at first a distinct odour of beer. The fermentation produces 
a transparent foam in which are found Eadoint/cr.-i Miujnmii 
(Ludw.) and a y ea.st, Saceharomi/ces Ludwigii (Hansen); this latter, 
Ludwig re,i,'ards as a stage of the Endomycis. Later a gelatinous 
slime is developed in tiie foam from the presence of Lracoiiostoc 
Lagcrheimii (Ludw.) Since this latter plant does not appear 
in the early stages of the disease, it cannot be the cause, and 
Ludwig says that the alcoholic fermentation due to the EiuJomyccs 
always appears first ; this conclusion requires confirmation. 

The milky outflow of trees.' 

Towards the end of winter and in spring a white foamy slime 
flows from freshly cut liirches or hornbeams. According to 
Ludwig, this is due to Endomyccs vcrnalis (Ludw.) 

Red slime-flux.' 

Ludwig found on the cut twigs of hornl)eam, a red fungus 
which he called Iihodomi/as drndrDporthcs. This may occur alone 
or along with the white flux, which it colours retl. 

Brow^n slime-flux.- 

This is found on apple-trees, elms, birch, horse-chestnut, 
poplar, oak, etc., from spring till winter. The slime, Ludwig 
says, is developed in the wood, and breaks through, causing 
the bark to decay. The wood is destroyed and smells of butyric 
acid. The slime contains microc(jcci (Micrococcus dcndroporthcs, 
Ludw.) and a form of Torida {T. monilioides). 

In Thuringia, many avenue-trees {e.g. chestnuts, apples, and 
birch), are reported to have been killed from this cause. I'hat 
the disease was really the result of a Bacterium, and that death 
was due to this slime-ilux, has yet t<> be pniveil, as Ludwig 
Idmself states. 

Black slime-flux. 

Ludwig considers Itriefly some forms Ir- found in a black 
sliuie-thix observed by liim on bcecluis. 

' Ludwig, Lthrbiich dtr ni'il. Kry}>to(jam»:ii, KS9'2. 
-Ludwig, Ctntralbl. f. liukl. u. J'ura.'iitciikituili , 1S8H. 



1 44 ASCOMYCETES. 

Chocolate-brown slime-flux.^ 

A slime-Unx of this colour appears on the stumps, of felled 
beeches ; it contains numerous forms of Oidium, and later Ascobolus 
Constantini (Roll) is developed in large quantity.'^ 

THE PARASITIC EXOASCEAE.s 

In this family are included tlie genera Exoascus, MagnusieUa, 
and Taphrina. The asci of most of the known species are 
produced from a mycelium which lives under the cuticle of the 
host-leaf, in a few {e.g. Magnusidia Jlava^, the mycelial 
liyphae are developed between the cells of the epidermis, 
while in others {e.g. M. potentillae), the mycelium permeates 
the whole leaf-tissue and the asci arise from hyphae situated 
under the epidermis. T. Laurencia and a few others have an 
intracellular mycelium, and produce asci inside the epidermal 
cells. A number of species are known to possess a perennating 
mycelium, in the remainder the hyphae are wholly used up in 
the formation of asci. 

The ascospores produce conidia before leaving the asci, which 
are therefore frequently found filled with minute conidia instead 
of the usual ascospores. In nutritive solutions the conidia sprout 
yeast-like ; on a host-plant, they give rise to a hypha which 
penetrates the cuticle. 

^Ludwig, " Ein neuer Pilzfluss d. ^^'aldbaume," Forst.-^iatunriss. Ztitschri/f, 
1893, and 1894. 

^Kriiger has found various micro-organisms, including a fungus (Prototheca) 
and several algae, in the slime-flux of broad-leaved trees. (Zopf, Beitr. z. 
Physiol, u. Morph. nied. Oryanisvien, 1894.) 

•* Sadebeck : (1) Unttrsuch. iib. die Pihgatfunr/ Eroascus, 1S84. (2) Kritische 
Untersuch. iib. die dnrch Taphrina-Arten hervorfiebrachfcn Baumkranlcheittn, 
1890. (.3) Die parasifisclie7i Exoasc.een, 1893. (4) " Einige neue Beobachtungen u. 
kritische Bemerkungen ub. die. Exoasceae," Ber. d. deutsch. botan. Ges., 1895. 

Johanson : (1) St tidier offer Sramj)siu(jet Taphrina, 1887. (2) Om Hvcunj^- 
sUiiitel Taphrina och dithorande Si-emka arter, 18S5.i 

Rostrup, Taphrinaceae Daniae, 1890. 

De Bary, Beitrcuje z. Morph. u. Physiol, d. Pike, 1864-1870. 

Giesenhagen, " Die Entwickelungsreihen der parasitischen Exoasceen. " Flora, 
Ertjiin-Atwjsband, 1895. With numerous figures from microscopic sections. 

Atkinson, " Leaf-curl and plum-jiockets." A contribution to the knowledge of 
the prunicolous Exoasceae of the United States. Cornell Unir. A(jric. Exj). 
Station, Bulletin 73, 1894. With numerous illustrations. 

Patterson, "A stiuly of N. America parasitic Exoasceae." Bulletin of the 
LaJ}. nat. hist., Univ. of loica, 1895. 

Smith, "Untersuch. der Morph. u. Anatomie der durch Exoasceen verursachten 
Deformationen." Forst.-uaturwiss. Zeitschrift, Munich, 1894; Italian, translation 
by Berlese, L'irisfa di Patologia, 1895. 



THK I'AIIASITIC KXOASCKAE. 145 

Tlie presence of a perenuatiiig mycelium is the cause of 
many so-called " witclies' brooms" on woody [tlants. In tact, 
the majority of the structures known by that name are caused 
by species of Exonscus, though these of barberry, silver tir, 
acacia, and buckthorn, are due to Uredineae, and others are 
ascribed to mites {Phi/fojifi(s). 

" Witches' Brooms " (Hexenbesen) are bushy growths, which 
remind one at tirst sight of stranger-plants growing, like 
mistletoe, on the branches of <jther plants. They generally 
originate from a bud which has been infected during the previous 
summer, either directly or through its subtending leaf. This bud 
produces a twig capable of abnormally increased growth, most of 
its sleeping buds are developed into l)ranches, and the whole 
system shows marked negative geotropism. (See Fig. '.)). The 
spores of the fungus are produced on the leaves of the broom. 

The characteristic features of a witches' broom are : that, 
without regard to the direction of the branch on which it is 
borne, it is negatively geotropic in a marked degree, and 
endeavours to develop like a terminal leader shoot ; -that the 
point of infection is distinctly conspicuous as the starting point 
(»f the broom. Sadebeck regards any twig-hypertrophy as a 
witches' broom, even that of Famsciis To<<rji/inrfii where there 
is no basal swelling and the twigs exhil)it only very slight 
negative geotropism. 

The forms of witches' brooms are ver}' varied. Amongst 
tlie best known are the hanging broom-like masses developed 
from buds of the leader shoots {e.(/. on cherry trees). As a 
result of the rich growth of twigs and their premature death, 
many of these brooms become tangled nest-like structures. The 
twigs in S(jme are much elongated, in others shortened, in 
every case, however, they are abnormally numerous. As a rule 
the original leader shoot, on which some lateral bud has developed 
into a witches' broom, shrivijls up and dies, its contents being, 
as it wer(% absorbed by the hypertrophied l)ranches. Other 
general features have already been discus.sed in I'art I. of 
this book. 

Smith* fijund tliat the iorm (jf the witches' broom is not 
fletermined exclusively by the fungus. The perennating my- 
celium indeed gives the tirst iia]»etus towards its I'ormation, 

' Smith, lur. fit. 
K 



U6 ASCOMYCETES. 

but it is completed by the weight of the broom itself, the 
excessive development of sleeping buds, and the premature 
death of twigs. Smith also investigated the anatomical changes 
occuring in witches' brooms due to Ecoascear. From his 
resume we select the following : " In a witches' broom the 
increased thickness of the twigs and branches is due to a 
proportionally greater increase in the bark than in the wood, 
the hypoderm, especially, having its cells more numerous and 
larger, while their normal arrangement in longitudinal rows 
is lost. The cork-cells are enlarged and retain their plasma- 
content longer. The phelloderni is better developed. In the 
sclerenchyma-ring, the primary bundles of bast-fibres are smaller 
and further apart from each other, or they may be quite 
absent ; the bast-fibres are shorter and have thinner walls ;. 
sclerenchymatous cells are more numerous, larger, and have 
thinner walls. The phloem is increased chiefly through enlarge- 
ment and increase in number of its medullary rays; phloem 
crystal-deposits tend to be multiplied. In the wood, the parts- 
most enlarged are the pith and medullary rays ; tracheae are 
more numerous, but their component elements are shorter ; the 
wood-fibres have thinner walls, wider lumina, and are often 
chamljered ; the normal course of the long elements is much 
disturbed by the greatly eidarged medullary rays. 

Sadebeck has recently divided the parasitic Exoasccac into 
these genera : (a) Magnusiella, with asci isolated on the ends 
of mycelial threads which lie between the epidermal cells ; in 
the other genera the asci arise from a subcuticular hymenium ; 
(b) TaphriTia, without a perennating mycelium ; (c) Exoascvs, 
with a perennating mycelium ; (d) Taphrinopsis may be taken 
as another genus. AscoiiiyceH he does not reckon with the 
Eox)asceae. 

Brefelcl divides the family into Eroascus, with eight spores in the ascus^ 
and Tajjhi-ina, with four-spored asci. Sadebeck shows, however, tha,t 
eight is the normal number of spores in all the species, and that variation 
therefrom is frequent, four or more spores or numerous conidia being 
formed. 

Schroeter separates the genus Magmisiella, as Sadebeck has done, then 
divides the remainder into Exoascus with eight-spored asci at time of 
maturity, while those with man^'-spored asci are placed under Tavhria 
(the older name given to Taplmna) 



THE PAKASITK EXOASCEAE. 147 

According to Sadeljeck, the Eroasceac may l)e divided as 
follows : 

Exoascus. 

The mycelium pereiinates in the tissues of twig or Inid. The 
subcuticular mycelium is developed from the perennating one, and 
becomes completely divided up, without any differentiation, into 
ascogeniHis pieces. The species are all parasites and produce 
hypertrophy of leaves, flowers, and shoots. 

A. The mycelium perennates in the inner tissues of the 
shoot. Thence, in the next vegetative period, it sends brandies 
into the leaves in process of development, at first into the 
inner tissues, but later subcuticular for the formation of re- 
})roducti\-e parts of the fungus. 

(1) Asci developed in the carpels, which in consec^uence 
become hypertrophied ; asci with a stalk-cell: E. pnnii 
Fuck. E. liostrvpianus Sad. E. cDmmunis Sad. E. 
Farlowii Sad. E. rJiizijJcs Atk. E. luiujipoi Atlv. /;. 
amfusiis Atk. E. recidomo])hiliis Atk. 

(2) Asci developed only in the foliage leaves. 

(a) Asci with stalk-cell : E. insififutc Sad. E. rcmsi 
(Fuck.). E. nanus (Joh.). E. deformans (Ueik.) A'. 
decijnens Atk. E. accriims Eliass. 

{h) Asci without stalk-cell : E. i^urpvrasccns (Ell. and 
Ever.). E. acsculi (Ell. and Ever.). 

(3) Asci developed on leaves and fruits. 

(a) A.sci with stalk-cell: E. tuiruhilis Atk. 

I!. The mycelium perennates in liie Ijuds (»f iiost-plants 
and issues thence in the ne.xt vegetati\'e period to develop in 
young leaves, subcuticular only. 

(1) Asci only on the foliagi' leaves. 

{a) Asci Willi a .slalk-ct'll : E. cmtae;/i (Fuck.). E. ininm- 
Sad. E. y\>stjii,iiicfii (West.) E. r^ii/i/ti//liis Sad. E. 
Uirgidna Sad. E. hcti/linv.s (Ko.str.). /.'. (djiinns {A oh.). 

(b) Asci without a stalk-cell : E. car/ihii lU<s[i. E. hartrrl- 

Dsprr/iti/s (Joh.). E. Kriir/iii YuiU. 
(-) .\sci on cariM-ls ; wilhout slalk-eell : E. idni inatnar 

Kiihii. K. ./(i/nnisn/iii Sad. E. r/i iioji/ioms (.loli.). 
{'">) Myceliuiii liiows intereeHuIaily. E. runn! ecrvi CJiesh. 



148 ASCOMYCETES. 

Taphrina. 

The whole mycelium is subcuticular and differentiated into 
one portion, which remains sterile, and into an ascogenous part. 
Perennation of the mycelium does not occur. The species pro- 
duce spots or hypertrophy on leaves or carpels. 

A. The fertile hyphae are completely used up in the for- 
mation of the asci. 

(1) Asci with a stalk-cell: T. hidlata (Berk, and Br.). 

T. ostryac Mass. T. Sadchcckii Joh. T. aurea 
(Pers.) (may also occur without a stalk-cell). 

(2) Asci without a stalk-cell : T. filicina Kostr. T. 

'polysiJora (Sorok.). T. carnea Joh. T. coerulescens 
(Mont, and Desm.). T. virginica Seym, and Sad. 
T. extensa (Peck.). 

B. The fertile hyphae are not completely used up ; asci with 
a stalk-cell : T. lefAilae (Fuck.). T. tdiai (Fuck.). T. celtis Sad. 

Taphrinopsis. 

Mycelium and hymenium developed only inside the epidermal 
cells. T. Laurcncia Giesh. 

Magnusiella. 

The mycelium inhabits the inner tissues of living plants and 
is always parasitic. Asci are formed at the extremities of 
branches of the mycelium, either between the epidermal cells 
or between cells of the inner tissues. The asci contain more 
than four spores, which generally produce conidia inside the 
ascus. The species generally cause leaf-spots, more rarely they 
appear on stems. 

(a) Asci without a stalk-cell : M. potentillae (Pari.). M. lut- 
escens (Rostr.). M. flava (Farl.). 31. githaginis (Rostr.). M. 
iimbelliferarum (Eostr. ). 

(b) Asci with a stalk-cell : M. fascieulata Lag. et Sad. 

Giesenhagen {loc. cit.) comes to the conclusion that the species 
of the parasitic Exoasceae have developed from a common 
ancestor simultaneously with the species of the higher plants 
inhabited by them, and that the development of host and parasite 



THK PARASITIC EXOASCEAK. 149 

has progressed side by side. He shows that Exoaseeae, living 
on related hosts, agree so closely in their ascogenous furnis, 
that it is evident they are generically related species. < )n this 
(fround he sets up a genus containing many species, and names 
it Taphrina. According to the host-plants, this genus is 
divided into four stems, and from it twenty-five species are 
separated off as the genus Magnusidla. ( riesenhagen's systematic 
division, gives a synopsis of the host-plants and their distri- 
bution as follows : 

I. Genus. Taphrina : asci club-shaped to cylindrical. 
A. i'7//a'.s-stem, on Ferns: asci .slender, clul»-shaped; tapering to 
Ijolh ends, rounded apex, greatest breadth in the upper quarti-r 
of the ascus. 

T. coriiu cervi (Giesh.) on AspicUnm aristatvm in East 

Indies and Polynesia. 
T. filirina (Kostr.) on Aspiclium sjnmdo.'^i'.m in Scan- 
dinavia and Jkilkan-peninsula. 
T. Lanrcnria (Giesh.) on I'trrifi quadHaurita in Ceylon. 
T. ffiscii-vlaf(( (Lag. et Sad.) on Ncplirixliuiii in South 

America. 
T. lutcscrm (Iiostr.) on Aspidinrn Thr/t/p/rris in Denmark. 

i;. JJi fi'lti-stt'iii on Jidlfforar : asci }ihun]i, t yliiuh-ical, with 
rounded apex or even a slight depression there. 

(1) On Ulmaceac: T. vinii (.Johan.) on Ulmvs montana and 

[7. campcsd-is in Central Europe and North America. 
7'. ci/fis (Sad.) on Crlfis ai/stndis in Xortli Italy and 
Switzerland. 

(2) On JJitidaceac. 
{<() On Bdida : 

T. (dj>iiiii (Johan.) on //. vniin in Scandinavia 

T. /Ill no. (.Johan.) on J!. nanii in Scandinavia. 

7'. Iietidae (Johan.) on i>. verrucom, J!, jmbctcois, ami //. 

turkcstanica in Ceulral Europe. 
T. hit id inn (Kostr.) on JJ. jtidnscms, and /.'. oduriifn in 

(Jermany, Denmark, and Scandinavia. 
y. nirncii (Johan.) on B. odnntfit, J>. jmhisn ns, J!, inni'i, 

B. intennidiu in Scandinavia, Tyrol, and Silesia. 
T. hnctcriospervuim (Johan.) tm B. numi in Scamlinavia 

and OrtM-nland. 



150 ASCOMYCETES. 

T. Jiava (Faii.) on B. iwpulifcra and B. pcqoyracca in 

North America. 
T. turgida (Sad.) on B. verrucosa in Germany and Tyrol. 
(6) On Alnus: 

T. epiphylla (Sad.) on A. incana in Europe. 

T. Sadcheckii (Johan.) on A. glutinosa in Europe. 

T. Rohinsoniana (Giesh.) on A. incana in U.S. America. 

T. Tosquinetii (Magn.) on A. glutinosa in Europe. 

T. alni incanae (Magn.) on A. incana in Europe. 

(T. alni glutinosae (Tubeuf) on A. glutinosn^ in Italy, 

Sweden, and Denmark.) 
{(■) On Gupidifcrae : 

T. ostryae (Mass.) on Ostrya carpinifolia in Tyrol and 

Italy. 
T. virginica (Sey. et Sad.) on Ostrya virginica in North 

America. 
T. carpini (Rostr.) on Carpinus Bdidus in Europe. 
T. austrcdis (Atk.) on Carpinus americana in North 

America. 
T. Kruchii (Vuill.) on Quercus Ilex in Italy and France. 
T. cocrvlescens (Tul.) on Quercus sessilijlora, Q. 2^cdun- 

cidata, Q. p^'^'-^csccns, Q. alba, etc., in Europe and 

America. 
{d) On Salicaccece : 

T. aurea (Fries.) on Populus nigra, P. pyramidalis and 

P. monilifera in Europe and North America. 
T. Johansonii (Sad.) on Fopulus tremula, P. tremuloides, 

and P. grarulielcnteUa in Europe and North America. 
T. rhizopliora (Johan.) on Populus alba in Europe. 
c PruniLS-^\jQvc\. on Roseiceae : asci slender and club shaped. 
(a) On Pomaceae : 

T. credaegi (Sad.) on Crcdacgus Oxycantlm in Europe. 
T- bullata (Tul.) on Pyrus commtmis and Cydonia japonica 

in Europe. 
(6) On Pruneae : 

T. deformans (Tul.) on Persica vulgaris and Amygdalus 

communis in Europe and North America. 
T. minor (Sad.) on Prunus Chamaeccreisus near Hamburg 

and Munich. 



THE tarasitk; kxuasceae. 151 

T. insititvif (Johan.) on Praaus Insititia and P. doinesticn, 

in Europe, and P. jnnnsi/lvanicc in North America. 
7'. (hxipicns (Atk.) on Prunns nnuriaina in North 

America, 
T. cct-fisi (Sad.) on Pruaus Ccrasv.s and /'. Chamaeccrasns, 

ill Europe, and P. ncinni in North America 
T. jj/'uni (Tul.) on Pn'./iiis domrHtiai. and 1\ Pud us in 

Europe and North America. 
T. iiiirahilis (Atk.) on Prunu.s migustifolia, P. Ittrrtuldiia 

and P. amcricana in North America. 
T. Farhncii (Sad.) on Prumis .srrofina in North America. 
T. confusa (Atk.) on Prunns virginiana in N<»rtli 

America. 
T Posfnipiana (Sad.) on Pru/ins sjnnom in Europe. 
T. commiinu (Sad.) on Prunus iiKiritima, P. puiailn, P. 

'iiiicrimna and P. nigra in North America. 
T. lijiigipes (Atk.) on Prunus amcriraiui in North America. 
T. rhizijJCS (Atk.) on Prunus trijii»rii in North America. 

{!■) On PofxiitiUeac : 

T. jtotcntiUac (Johan.) on P. sghrsfris, P. cioiadmsis, and 
P. gco'idcs in Europe and Noitli America. 

U. AcsculuS'^U'XW iiu Eurgdicnr : asci phimit, cylindrical, with 
Jlat or roumled apex. 

('/) On S'rpindaccnr : 

T. ncsculi (Ell. et Ever.) on A>s,ul,is ndi/orninf in 
California. 

{h) On Anacardiaceac : 

T. purpurnscms (Robins.) on Pliu,^ rojinl/ino in Ndrlh 
America, 
(r) On Accrinrar : 

T. ticerieula (Mas.s.) on A. rmnjicstn and A. J's, udnjilafnnus 

in Italy. 
T. (urriiui (Eliass.) on A. platduoidrs in Sweilen. 
T. jn>li/.yKini (.Tdhan.) <>n A. fn rturlru m in Murnpc'. 

J I. C.nus. Magnusiella : asci ovoid or spheroidal. 

.)/. '/dJuiijiHis (Sad.) on Agrustrninia (Hthago in l)i'nmark. 
M. umhrUifcrdrmn (Sad.) on Ifrrticleiim Sphwulglium, 
Peuccdduuiu jiiilusfrr, ami /'. (h-nistlininn in Kiiropc. 



152 ASCOMYCETES. 

The E.wa'sccae may be grouped, according to the symptoms 
of the disease produced, as follows ; for this purpose we shall 
class all tlie species as one genus, ' Exoascus' (or Tcqyhrina): 

I. Species which cause deformation of the ovary or other part 
of the fruit. 

U. pruni (Fuck.) on Pru7ivs domcsfica, P. Padus, P. vir- 

giniana. 
E. RostruinanuH (Sad.) on PriinuH spinosa. 
E. communis (Sad.) on Prunns 2'>y'>nillc(, P. maritima, P^ 

nigra, P. americana. 
E. Farlowii (Sad.) {E. varins, Atk.) on Prunus serotina,. 

causing also deformation of twigs. 
E. longipeii (Atk.) on Prunus americana. 
E. confusus (Atk.) on Prunus virginiana. 
E. rhizipcs (Atk.) on Prunus triflora. 
E. cecidomophilus (Atk.) on insect-galls on the fruits of 

Primus virginiana. 
E. miraMlis (Atk.) on Prunus angvstifolia, P. hortnlana^ 

P. americana. 
[Also species on Prunus sidjcordata, P. Cliicasa, and P. 

2JennsgIvanica.] 
E. alni incanac (Ktihn) (E. amcntorum, Sad.) on Alnus 

incana. 
E. alni glutinosae (Tubeuf) on Alnus glutinosa. 
E. Rohinsonianus (Giesh.) on Alnus incana. 
E. Johansonii (Sad.) on Populus trnnula, P. trcrnuloidcs, P\ 

grandidentata. 
E. rhizopliorus (Johan.) on PopuluH aUm. 

II. Species which (1) produce witches' brooms, or (2) at least 
cause deformation of shoots ; asci produced on the leaves. 

(1) E. rpiphyllus (Sad.) {E. horecdis, Johan.) on Alnus 

incaiui (uniform grey coating of asci on both sides 

of leaf.) 
E. turgidus (Sad.) on Bctula verrucosa (coating of asci on 

under surface accompanied by slight crumpling of 

leaf). 
E. betidinus (Kostr.) on Bctula ^)?//>('.sy'C71.s and B. odorata 

(coating of asci on under surface). 



THE I'ARASITR' EXOASCEAE. 153 

E. alpi/u's (Johan.) on Bctvia nana (coatinu on under 

surface). 
E. carjnni (Rostr. ) on Caiyinvs Betvlns (coatin<i on under 

side, and crunij^ling of leaf). 
E. cerasi (Fuck.) on rrunv.s Oirasvs and /'. (ivium (coatiufj, 

chieHy on under side, and cruniplinu; of leaf). 
E. insifitiac (Sad.) on Frunvji Insititia, 1\ domediai, P. 

IKHnsylranica, {F. npinosa ?) ; (coating on under side, 

and crumpling of leaf). 
E. acerinus (Eliass.^) on Acrr j)litfaiioi(h's ; (asci on lioth 

surfaces). 
E. acsculi (E\\. et Ever.) on Arsci'/t's califoi'nica ; (coating on 

both sides). 
E. Krucliii (Vnill.) on Qnerct'n Tier. 
E. cornu cervi (Giesh.) on AspuHiim aristatvm. 
E. Laurencia (Giesh.) on J'frris qnadriain-ifa (with deforma- 
tion of leaves). 

(2) E. iitrniis (Johan.) on Bdula nnuii (white coating on 

upper side). 
E. hadei'ios/k'riui's (Johan.) on Beti'hi nann (coating on luitli 

sides). 
E. decipiens (Alk.) on Fnnins (nini-icami (coating on both 

sides). 
E. parparaHci US (Ell. et Ever.) on Blms cujialli/in (crum- 
pling and red-colouration). 
E. 7\).squinrtii (West.) on Alans (//nfi/iosa and A. tjlnt.x 

incana (large Ijlisters and elongation of shoots). 
E. jri'uni (Fuck.) on Prunvs damcstiea (blistering and criim- 

pling). 
E. minar (Sad.) on Bri'/tns ChmiKicn rastis. 
E. deformans Berk, on Prrsmi rnUjaris and Anii/r/dalns- 

(•ommvnis (blistering and crumpling). 
E. rrtittufji (Fuck.) on Cratai'diix Ori/aciudha (spots ami 

blisters on the leaves). 
E. mindiUis (Atk.) on I'rvnns aiiffnstlfoliti, /'. Itortnlinai, 

P. nmerica.na (on twigs, li'aves, and fruit>i. 
E. iritis (Sad.) on Ciltis imsfndis (brouii sputsi. 
E. f/if/i'i'/i/iis (Iiostr.) on A>/r()s/i iiniiii (>'if/iiii/i>. 

'Srni.^hi 1,1. Aku<l. lluudl. 'Jd, iHiC. 



154 ASCOMYCETES. 

III. Species which produce (1) pustule-like outgrowths, (2) 
leaf-spot, or (3) smooth coatings of asci. 

E. aureus (Pers.) on Fojndus iiigra (incl. jitjramidalis) 

and P. monilifcra. 
E. polysporus (Sor.) on Acer tartarimim and A. Psetido- 

platanus. 
E. bullattis (Berk, et Br.) on Pyrus communis and Cj/donia 

jap)onica. 
E. carneus (Johan.) on Betula nana, B. odorata, and B. 

intermedia. 
E. coerulescens (Desm. et Mont.) on Quercus 2>«bcscens, Q. 

sessilifiora, Q. Cerris, Q. laurifolia, Q. ruhra, Q. tinctoria, 

Q. aqucdica. 
E. Sadebcckii (Johan.) on Alnus glutinosu. 
E. idmi (fuck.) on Ulmus campestris, U. montoMa, and U. 

americana (spots and blisters). 
E. virginicus (Sey. et Sad.) on Ostrya. virginica. 
E. aiistralis (Atk.) on Garpinus cimericanus. 
E. Jilicinus (Eostr.) on Aspidium sp)inidosu.m. 
E. potentillae (Farl.) on Potcntilla geo'ides, P. coMccdcnsis, P. 

sylvestris. 
E. githaginis (Eostr.) on Agrostemma Githago. 
E. luiescens (Eostr.) on Pulystichum T-hclypteris. 
E. uriibelliferarum (Eostr.) on Heracleum Spliondylntm, Pcu- 

cedanum pcdustrc and P. OrcoseliniLin. 
E. ostryac (Mass.) on Ostrya carpinifolia (brown spots). 
E. hetulae (Fuck.) on Bctida verrucosa, B. puhcscens, B. 

turliestanica (whitish spots). 
E. jicmus (Farl.) on Betula populifolia, B. papyracca. 
E. acericolus (Mass.) on Acer campestrc and A. Pseudo- 

pjlatanus. 
E. fasciculatus (Lag. et Sad.) on Nephrodiwm (whitish spots). 



The following are some of the more important species of 
Exoasceae : 

Exoascus pruni Fuck. (Pocket-plums). This attacks the 
ovaries of Prunus domcstica (plum), P. Pctdus (bird cherry), and 
P. virginiana, causing the mesocarp to grow rapidly, whereby 
the fruits increase in size and become much changed in form, 



THE PARASITIC EXOASCEAE. 



155 



wliile the stone, includin.^f the embryo, remains stunted. (Fig. 
49.) The "pocket-plums" (fools or bladder-plums) dry up, and 
remain hanging on the tree till autumn. De Bary found <»n 
the plum a withering of calyx and stamens resulting from the 
ilevelopment of the hymenium of this Exoascus ; on the bird 
cherry, according to Magnus and Wakker, enlargement of the 
.stamens occurs. Sometimes a considerable thickening and 
twisting of the young shoots takes place, and their leaves 
curl up. 




m/^^: 






i . 4S. — Ej-oaicus j)n'.iii. Twig of riiiiii, with fmir ilcfnriiicit fruits; nuc 
iiuriiial pliiiii IH pjirtiiiUy hiddeu, the other in in the middle, i iKitiind size, 
(v. Tubeuf del.) 



The mycelium hilieiiiatcs in thi' sdfi bast nf ilie twigs, and 
proceeds thence in sjiring inlu young shnots and ovaries. 
According to De JJary, the infected ovaries doulile their size 
in two days, and are full grown in eight days. 'I'hc asfi form 
a close layer under thr ruticlc of the ovaiy, and liiially 
riiptnn* it. 



15G 



ASCOMYCETES. 



Exoascus Rostrupianus Sad. This fungus causes " pockets " 
on Frunus spinosa (slue) similar to the preceding species. 
According to Sadebeck, the asci in this case are more slender. 





Fig. 49. — Exoascus pruni. Malformed 
Plums — "pocket plums"; one which is 
cut shows the rudimentarj- stone. 

i- natural size. (v. Tubeuf phot.) 



Fig. 50. — Exoascus prv.ni on twig of Pruni'.s 
Padv.s (at end of July). Four of the ovaries 
are malformed, (v. Tubeuf del.) 




Fio. 51. — Exoascus proni. Young twig.s of Plum, showing effects of mycelium. 
The shoots are swollen and distorted, one diseased leaf remains hypertrophied 
and much crumpled; on one spur a norm.al and a "pocket" plum are borne. 
Specimens from the Museum at Geisenheim. \ natural size. (v. Tubeuf phot.) 




THK PARASITIC KXOASCEAE. 157 

Exoascus communis Sad. This produces pocket-plums on 
Pricnus aniericana, F. jiii)iiil((, and P. iiKiritinKi in America. 

Similar " pockets " also occur on Pranus suhcurdata, P. Chicasa, 
and P. pinasi^lrtiaico, in America, as a result of some Eniascus. 

Exoascus Farlowii Sad. produces similar 
deformation of carpels and floral envelopes on 
Pri' Ill's sf/rtfinn in Xorth America. 

Exoascus Johansonii Sad. produces carpel- 
enlargement on the female catkins of Populus 
trrmala, P. trcmaluides and P. graiulidentdta ; the 
contents of the asci are yellow. (Fig. 52.) The 
anatomy of the deformed ovaries has just l»een 
<lescriliod liy Sadebeck.^ 

Exoascus rhizophorus -lohan. causes similar vu-,. b-i.—E.(owscus 

Johamonii Sad. on 

enlarLrement of the temale catkms oi Poindns Popv.iustremuia. (v. 

'^ ■' TubeufdeL) 

nihil , 

Exoascus alni-incanae Kiihn {Ex. amcntoram Sad.) This 
species is readily distinguished by the absence of a stalk-cell 
on the ascus. It causes increased growth and enlargement 
of the seed-scales of alder catkins, the fruit itself being seldom 
attacked. Tlie Heshy bladder-like outgrowths at first appear 
as little red processes ; later, tlie asci are developed on the 
outer surface as a wliitish coating. On many of these red 
processes may still be recognized the trifid apex of the normal 
scale, (this is really formed from five smaller scales fused into 
a single large one with a trifid apex). A number of these 
red outgrowths are generally present on each infected catkin, 
yet the alders continue to flower vigorously every year. 

Wakker,- in investigating the anatomy of the deformed scales, 
found the following alterations : — the scales are increased to many 
times their original size and contain two cavities; all i)arenchy- 
matous cells become regular and iso-diametric ; lignificatitm (»f 
the elements of the wood is more or less interfered with, and 
fewer wood-fibres are produced ; there is an accumulation of 
transitory starch. 

Exoascus alni-glutinosae Tubeuf. This is a new species 
distinguished by v. Tubciif in 1895. It oeeurs in tlie Sudetic 
mountains, Italy, Denmaric, and Sweden, on Altiifs t//i(finos(t. 
Its habit is similar In that <>\' E'. nliii-incanar, Imt the asci 

' Sadebeck (See Litonitiiri'), 4. p. 144. - J'niiif^hiim'n Ja/trhnrh, 1S!»*J. 



158 



ASCOMYCETES. 



contain only coniJia, whereas those on Alnus-incana are said 
by Sadebeck to contain only ascospores, unless on very rare 
occasions. In the lower and higher Alps, although both species 
of alder are not infrequently found together, yet the Exoascus 
is found only on Alnus incana, and no species occurs on A. 
glntinom. 




Fig. 53. — Exoascus alni-incanae in catkins of Alnus incana. Many of the scales 
are developed as elongated red soft tongue-like structures, on which the asci^are 
produced as a whitish coating, (v. Tubeuf phot.) 



Exoascus epiphyllus Sad. (Ex. horcalis Joh.^) The witches'- 
brooni fungus of the white alder {Alnus incana.) 

The author- was the first to describe and figure this form 
of disease in 1884; and Sadebeck recently succeeded in pro- 



^ K. Sven. Vet. Akad. 1885 and 1887. Tubeuf, Botan. CentralhL, 
- Tubeuf, Beitrdge z. Kenntniss d. Baumkrankheiten, 1888. 



1890. 



THK PARASITIC' KXOASCEAE. 



\b'J 



duciujj; the brooms by artificial iiit'eetiou oi' alder. Tlie disease 
is common and epidemic, and a single tree may carry as many 
as a hundred brooms. 

The witches' brooms are 
composed of many thickened 
twigs, beset with an abnor- 
mal number of lenticels, 
and the point of infection 
shows a distinct swelling, 
from which the broom tends 
to turn directly u^iwards. 
The leaves are somewhat 
modified, they are larger and 
thicker than the normal, 
they unfold later and wither 
earlier, while their stipules 
remain attached for some 
time. The brooms of alder 
only survive a few years, 
and by their decay cause 
the death of large branches, 
and frequently of the whole 
tree. 

The asci, which are sunk 
in a depression of their 
stalk-cell, form a white 
coating on both surfaces of 
the leaves. The mycelium 
hibernates in the buds. 

Exoascus turgidus Sad. 
causes the iuriiuiliun oi 
witches' brooms on Bctnln 
verrucosa. The leaves form- 
ed on the lirooms are some- 
what crumpled, and the asoi 
are produced on their lower 
surl'acL-. 

Exoascus betulinus 
liostr. produces witches' 
blooms (jU llilnlii i)iihisi'ini< and /A othirntu. 




Fl<i. .14. — h'jootCHt (i>ijilii/lliit. Witches' brunni 
in first yuur, showiiiK HWelliii); iit tho jmiiit <i( liifii-- 
tiiiii. The IcuvcM luo uhi'uily whcil In iiutuinii, whtlo 
thu iiorinal »tlll rfinitiii J iiiitiiril xWv. After 
V. TiiJaMif.) 



160 



ASCOMYCETES. 



* Witches' brooms on birch are very common in Scotland. 
They appear as tangled masses of twigs, which at first sight 
give the impression of some bird's nest. I have frequently 
examined the leaves borne on these brooms, and have never 
failed to find the asci of an Uxoascus. Sadebeck gives in 
his monograph the two above-named species as found on birches 
bearing ^.■itches' brooms. Mites (c.y. Fhytoptus) have also been 
given as the cause of these malformations. On close examination 
of brooms which undoubtedly bore Exoascas, I found that a 
Ijroom results from a prolific development of small twigs on 
one or a few knotty swollen parts of a branch. Each central 




Fio. 55. — Witches' Broom of the Hornbeam. Exoascus carpini on Carpinus Selulus. 
The bush measures about 1 metre across, and arises laterally from a branch, the 
upper normal part of which has been removed, (v. Tubeuf phot.) 



knot we may regard as the position of the bud which was 
first infected, and from which the broom system took its 
origin. As one result of the attack of the fungus, the greater 
number of the buds in the axils of the scales of the infected 
bud have grown out as twigs, but not into well-developed 
ones. In consequence, nearly every twig has been killed back 
by the winter, but not completely, so that from each twig- 
base has sprung a new crop of stunted immature twigs like 
the first, and equally liable to be killed in the following winter. 
Thus has arisen that tangled mass of dead or sickly birch 
twigs which we call a witches' broom. [Edit.] 



THE PARASITK' EXOASCEAK. 



161 



Exoascus alpinus Johau. and Ex. nanus .rohan. Both occur 
on Betula ncnvi, and induce formation uf hypertrophied twigs. 




wliolu loft Biiic foniiM ;i birj,'c l>rcK>in. A Hiimllcr cxiiini)lu ociupie!* tho Biiiiiiiiit of 
tho crown, while another hanh'^ <l<>wnw:iril.4 to tho riKl't- •» winter condition, 
(v. TMl)ouf i-hot.) 

The mycelium of Er. nunus hilx-rnates in twin's, ami iifiirlialL'S 

I. 



162 



ASCOMYCETES. 



into the inner tissues of newly-formed twigs and leaves. The 
mycelium of E.c alpinus passes the winter in the buds, spreading 
thence in spring into young twigs and leaves. 



it W ! K 










Fig. 57. — E.coasciis cerasi on Prunus C'erasiu. Clicrry-treo in blossom, with the 
exception of four witches' brooms. The tree is as yet leafless except the brooms, 
which are in full foliage and show up dark. (v. Tubeuf phot.) 



Exoascus carpini Eostr. is common on Carpinus Betukts (horn- 
beam) (Fig. 55). The brooms produced are bushy and densely 
leafed ; the twigs are thickened and much branched ; the leaves 



THE tarasitk; exoasceae. 



163 



are suuiewhat curled up, ami the asci appear on tlieir lower 
surface. 1 

Exoascus cerasi Fuck, occurs very coininonly on ciierry 
trees (rrumi^ (_', rostis and P. tiviii.in) both in Eur(jpe and America. - 
It produces witches' brooms, which may be large, upwardly 
<lirected, bush-like, and very conspicuous structures, with 
numerous thickened and elongated twigs (Fig. ."3); or they may 
be small, hanging bunches of twigs with upturned free ends. 
The leaves are somewhat W'avy, slightly ^crumpled, and reddish ; 
on their lower epidermis tliey bear asci. and full olT prematurely. 




(v. Tiibcul iihot.) 



I Ik'. 



Tile brooms are visible at a considerable distance in ihc winter 
(Fig. 56), while they are even more conspicuous during the 
flowering season (Fig. r>7). At the latter time, before the 
leaf-buds open, the cherry trees are normally covered with 
white bloss(»m, while the brooms bear leaves only, ami rarely 
Ijlossom. Hence they produce little or no fiuit. Kach tree 

' Wehnier {/iof. X>iinit'/ lS!)(j) ili.scusse.s tlio foniiiaioii of tlusc witcht'M* 
ljr<M)iii8. (Kdit. ) 

•■ E. Kfithiiy, '• Ulxi- ilio lluxenheseii il. KirsclibiUimen." — Silzniiysln r. if. A'. A', 
Ahtil. -.1, U'i.ii, ISNl. 



164 



ASCOMYCETES. 



may bear several brooms, and every tree in a fruit-garden 
may be attacked, so that this disease has assumed consider- 
able economic importance. As a preventive measure, the removal 
of all brooms at the time of pruning the trees is strongly 

recommended. 

[According to Shirai {Tokio 
botanical ma<jazinc, 1 8 9 5) witches' 
brooms are produced in Japan 
on Prunvs j^seudo-cerasics, by a 
distinct species, Ux. ^we^^r/o- 
ccrafivs.] 

Exoascus minor Sad. This 
species induces hypertrophy of 
shoots of Prv/iius ChamatceraHus 
and P. Cerasus, but cannot be 
said to cause formation of 
witches' brooms. The mycelium 
hibernates in the buds, and 
spreads only underneath the 
cuticle, while that of Ux. cerasi 
lives in the tissue of the twigs 
and leaves. It is characteristic 
of this species that only leaves 
here and there on a twig may 
be attacked, while their neigh- 
bours remain quite healthy; botli 
Howers and fruit may also he 
borne. Diseased leaves appear much crumpled, and Sadebeck 
states they have an odour of cumarin ; they turn brown pre- 
maturely and fall oft. 

- Exoascus insititiae Sad. is found on Prunvs domestica and 
P. Insititia in Europe, and P. -pcnnsylvanica in North America. 
It causes formation of witches' brooms smaller than those on 
the cherry tree, yet probably more common in the fruit garden. 
They bear no fruit, and are a source of considerable loss. 
The mycelium hibernates, like that of E,r. cerasi, in the bark of 
twigs, and spreads in spring into the buds. 

The leaves of the host bear asci on the lower epidermis ; 
they are always more or less cuiled up, and fall off early. 
To prune off all brooms is the best preventive measure. 




Fig. 59. — Twig from witches' broom in 
foliage, as in Fig. 67. Photographed at same 
time as Fig. 58 for comparison, (v. Tubeuf 
phot.) 



THK PARASITIC EXOASCEAE. 



165 



Exoascus deformans (P>erk.) causes the "curl disease" of tlie 
}it'ai-li {I'lrsirii n/h/iiris), and may inflict Ljreat injury. The 




-Ejomcus minor. Curl disease of CIkii' 



mycelium hibernates in bark, pith, and meduUaiy rays of twigs, 
so that it reappears each year. An U.ax/scus, which occurs 





VUi. 1)1. --Sxoa/cuf ilijhriiiant. CointxiriBoii of iioriiiiil »ectioii of U'uf of I'runin 
Ptrtiea with a hyiK-Ttrophiod one, B ; in the lutter the niyceliiil hyphiie have 
been 8liKhtly Nhiided. The seetiimK are from dilToreiit juirts of the twiuc leaf, and 
are drawn with the Muine nia»(nitieution. (After W. 0. Sinitli.) 

<iii the iihiKtnd ( .t/ii>/i/i/ii/i's luiniiiunis), rt'seudtk'S Ex. (h/onnans 
.S(» cUjscly that they arc miw rnu';ii"d('<l as ihi* same species. 



166 



ASCOMYCETES. 



This is supported by Smith's investigations, in which an an- 
atomical comparison of diseased twigs of peach and ahuond 
showed no difference in the pathological effects. 

Exoascus crataegi Fuck, occurs on Crataegus Oxyacantha, 
and causes red swellings on the leaves and flowers, accom- 
panied l)y hypertrophy of shoots in which the mycelium 
perennates. 

Exoascus Tosquinetii (West.). The deformation caused by 
this species is frequent on the Ijlack alder (Ahius ghdinosa). 
The thickened, elongated, wrinkled twigs render attacked parts 
very conspicuous in contrast to the normally developed parts of 

the tree. The leaves may l:)e 
wholly attacked and much 
enlarged, or they may only 
be hypertrophied at places so 
as to form pustule-like swell- 
ings. The epidermal and 
mesophyll- cells of diseased 
leaves become greatly en- 
larged. 

Exoascus aureus (Pers.). 

The leaves of the black poplar 

{Populus nigra) attacked by 

this parasite exhibit pustules 

(Fig. 62). The asci are 

formed as a golden coating 

on the concave side of the 

pustules, which is, in most 

cases, the under side of the 

leaf, rarely the upper. The 

cells forming the pustules 

have thicker walls and a 

somewhat different shape from the normal epidermal cells, and 

they are not unfrequently sub-divided by walls of secondary 

origin (Fig. 63). 

According to Smith, the cells of the palisade parenchyma have 
also thickened walls, as well as being elongated and occasionally 
chambered ; the cells of the spongy parenchyma are enlarged and 
have thicker walls ; so also are the cells of the collenchyma of 
the leaf venation. 




Fig. (i'J. — E.roascv-S aureus. Leaf of Po'pulu 
nigra, showing the p\istule-like swellings, (v 
Tubeuf del.) 



THE I'AHASITIC KXOASCKAE. 



ig; 



Exoascus coerulescens (Mont, et I)esni.) produces similar 
blisters on oak leaves. 




Fi(i. d'i.—Ejousms aurevs. Leaf section from the mar^ii of a swelling, showing 
normal and hvpertrophied tissue. The cells of the swelling are abnonnally 
elong-dted with thickened walls, and some show secondary cell-division. The 
bases of the asci are wedged in between the cells; one ascus is shown with 
conidia. (v. Tubeuf del.) 

Exoascus carneus -lohan. occurs on leaves of Bdula odorata, 
JJ. n(iii((, and B. intcnnedia. The pustular out,!j;ro\vtlis ri.se above 




Fiti. 04 — Ejouscvs cornevs on Bili'la odorato. (v. Tubcuf del.) 




Via. 65. — Section of nonnal leaf of IlttuUi 
odorata. (After W. (i. Hniith.) 




Fui. tUl.- f'ectii'ii of loaf hy|H.Ttro|>liicd by 
attack of Jijonm-ini riiiiifii.t\ the a.nci of the 
finiKiiH emit tlio upjior oiildiTinl^t. Drawn 
with the nauie niagiiltUattun an Ki^. (>^, for 
.■.pini«irli..n. (Afti-r W. C. Smith.) 



168 



ASCOMYCETES. 



.4 



the upper surface of the leaf (Fig. 64), and the upper epidermis 
alone bears the asci. In the pustules, the leaf may be two to 
four times as thick as healthy parts. The greatly increased 
thickness is due for the most part to enlargement of the cells 
of tlie mesophyll, while at the same time their normal arrangement 
is completely lost (Figs. 65, 66). The elements of the fibro- 
vascular bundles are enlarged ; the cells of the upper epidermis 
are more numerous, contain a reddish sap, and their walls are 
thickened. All chlorophyll is destroyed in the pustules. 

Ex. polysporus (Sor.) causes swollen 
spots on leaves of Acer tartaricum. 

Ex. bullatus (Fuck.) causes similar 
spots on leaves of pear {Pyrus 
communis) and quince {Cydonia 
japonica). 

Ex. Sadebeckii (Johan.) causes 
simple spots on leaves of Alnus 
glutinosa. 

Many other species, named in our 
list and in Sadebeck's papers, will be 
found described in detail in one or 
other of the papers already cited. 



fTH 



1\-. 






X. 



7 



Fig. (n .— Ejmciscus polysporus on 
Acer tartaricum from Sweden. The 
uttacked leaf shows pale spots with 
brown centres. The former result 
from the Taphrina, and are covered 
V)y a white coating of asci ; the brown 
spots are produced by other fungi 
which grow on the spots already 
killed, i nat. size. (v. Tubeuf del.) 



B. Carpoasci. 
{Ascomycetes loitli Sporocarps.) 

The a.sci of the Carpoasci are not 
formed directly on the mycelium, but 
from a special part of it, which 
becomes more or less enclosed in 
another non-ascogenous portion. From 
these two portions of the mycelium a sporocarp is formed, in 
which we can distinguish three distinct constituents : {a) the 
envelope containing (&) the paraphyses and {c) the asci. 
Amongst the Gymnoasci the envelope, if present, is never 
more than a loose hyphal tissue, but in the Carpoasci both 
paraphyses and envelope are present, the latter with char- 
acteristics distinctive of each species. The sporocarps of the 
lower Carpoasci are completely closed structures containing 
only one or a few asci ; those of the higher forms, however, 



CARI'OASCI. 169 

contain many asci, and tlie envelope is pierced by a definite 
aperture. 

Brefeld eiuleavours to explain the ascocarp tjf the Eiysipheae fmni the 
spurangial structures of the Zygosporeae {lihizopus and Mortierellu); ]Je 
Bary' and Zopf," on tlie other hand, see in it an oosporangium, like that 
of the Oosporeae. I'nder this latter view the envelope of the C'arpoasci is 
morphologically homologous to the antheridia of the Sapmlegnieae and 
Peronosporeae. In the latter group the antheridium generally takes the 
form of an open fertilization-tube, in the Saprolegnieae it remains closed, 
and is physiologically no longer an antheridium. Zopf found in one of 
the Saprolegnieae {Dictyuchus carpophorus), an envelope resembling that 
*)i the Erysipheae, and on this ground he, along with De Bary, links the 
Erysiplieae to Uomycetes like Achjla through f<n-ms like Pod(>.<i>lini'ri(. 

The reproductive cells or ascospores result from direct nuelear 
ilivision in.side the asci. They are generally simple and uni- 
cellular, but it is not uncommon to find that, by the formation 
of cross and longitudinal walls, each spore forms a cell aggre- 
gation (sporidesm of iJe Bary), with each cell capable of 
germination on its own account. The number of cells in each 
aggregation, as well as the size and shape of each cell, are in 
many cases constant, and form }ioints for the determination of 
species. Appendages to the spores are characteristic of many 
species. 

The Carpoasci possess, in addition to ascos}tores, other 
means of reproduction. Thus, thick-walled chlamydospores occur 
either in the mycelium as resting-spores {H///ioi/ii/ces), or as 
spores (oidia) resulting from a breaking-up of hyphae. 
Many kinds of conidia may also be produced, some h\nn the 
germinating ascospores, some abjointed from a branch of the 
mycelium or from some tbrm of special conidiophore. These 
latter may be produced isolated, or massed together in hollows 
of the stroma, or in closed structures resembling ascoGirps, 
and called ])ycnidia. The various iorms ol' rejiroductive organs 
presented by each species will be more closely considered as 
we proceed. 

The Carpoa.sci arc arranged, according to tlu' struct uri' of 
the ascocarps, under the following divisions: — the I'eris- 
poriaceae, I'yrencnnycete.s, Hysteriaceae, Discomycetes, and llel- 

' l>t; Biiry. /i>ifni'j' -.. morjili. ii. /'hijslo/. ,/. I'ilz,-. 

-Zopf. /{i i/niijf -.. I'liyniol ii. iiior/i/i. ii' iil- r < h(/iiiiisiiii n. Ilrft .'{, I8!IS. 



170 ASCOMYCETES. 

vellaceae. All these groups include forms parasitic on plants, 
except the last, which is saprophytic. 

Gi/mnoascus and Ctcnoinyces are forms intermediate to the 
(xymnoasci and Carpoasci ; they have the asci enclosed in a 
slimy envelope of mycelial tissue. We place them along with 
the former group, although Brefeld puts them in the latter. 

PERISPORIACEAE. 

The Perisporiaceae are distinguished by having an ascocarp 
or perithecium which never opens, so that the asci are only 
exposed by decay of the envelope. It includes three families, 
the Erysipheae, Perisporieae, and Tuberaceae. 

ERYSIPHEAE. 

The members of this family all live as parasites on the 
outer surface of plant-organs, and have a much-branched, 
white, septate mycelium, which derives nourishment from the 
interior of the epidermal cells of the host by means of 
haustoria of various forms. 

The Erysipheae or Mildews appear as white spots and 
coatings, on which the ascocarps or perithecia appear later as 
black points. On microscopic examination, the perithecia 
will be found to contain one or many asci, while externally 
they are beset with thread-like appendages of a definite form 
and definitely arranged, so that they are of great use in 
determining the various species. 

The fungus passes through the winter by means of the 
ascospores. These do not ripen till spring, when, liberated by 
decay of the ascocarp, they are carried to plants, where they 
germinate, especially on the leaves, and form a mycelium. In 
addition, the fungus is propagated throughout the summer Ijy 
means of conidia produced on special conidiophores in acropetal 
series or chains, of which the distal terminal conidium (acrospore) 
is the oldest and largest. The ripe conidia fall oft' and 
produce a mycelium which is at once fixed in place by the 
formation of haustoria. 

Prevention. " Sulphuring " is the method chiefly used for 
combating mildew. This consists in dusting powdered sulphur 
(flowers of sulphur) over the plant threatened witli attack. 



erysii'Heal;. 



171 



The operation is done by hand or by special implement. One 
of the best known of these is the " Sulphur I'utf." This 
consists of a brush with a hollow stem to contain tiowers of 
sulphur, the end of the stem being perforated to allow the 
sulphur to escape on to the plant. Sulphuring must be 
carried out during dry weather to prevent the powder being 
washed away. It has also to be frequently repeated, so that 
young grdwing shoots, tiowers, fruits, leaves, and all parts 
liable to attack, may be kept well dusted. Sulphur jtrevents 
germination of conidia on the leaves; it also kills the 
mycelium, while the plant itself remains uninjured. 

Besides sulpliuviug, \arious eoi)per soluiidiis give very good 
results, while at the same time they act as a preventive 
against the false mildews {Flasmo^iara , Pcrono>>j)or(i, etc.). 

Sphaerotheca. 

Perithecia spherical with tiiread-like a})pendages; they contain 
one spherical ascus with eight colourless oval ascospores. 




V\i,. M. — Knt(.i„,hl,,r. - • 

cuiitliit( on tlie leaf, cHiii;ci.illv i>ii th 
curliil ii|.. (v. Tiibuuf pliut.) 



11' iMj^lih fci III.-, a wlitli liJi.il^ 
.\\Li .-l.ii ; tin liavifc arc iilci' Im.li- fl Iimm 



172 



ASCOMYCETES. 



-•^ 



Sphaerotheca pannosa Wallr. (Britain and U.S. America). 
The Eose-niildew. The mycelium forms a thin white coating on 
the leaves, and is nourished by lobed haustoria inserted into 
the epidermal cells. Young leaves or buds when attacked 
become more or less deformed, their function is interfered with, 
and death may result. In this way great damage is done in 
rose-gardens. This parasite also attacks young letrves and fruits 
of peach and apricot. 




Fio. 69. — Sphaerotheca jtannosa on Peach. The mycelium and conidiophores 
are shown on the epidermis of a leaf. (After Tulasne.) 



Kose-mildew is propagated during summer by ovoid, vuii- 
cellular conidia abjointed in acropetal series from erect conidio- 
phores. The perithecia have short simple appendages, and 
contain elliptical spores. 

The disease may be combated by " sulphuring "; according to 
liitzema-Bos, spraying with Bordeaux mixture has also shown 
good results. 



SPHAEROTHECA. 



173 



Sphaerotheca (Podosphaerai castagnei Lev. (Ihituin and 
U.S. America). The Hop-mildew. The mycelium is found ^n 
all parts of hop-plants, causing considerable dama<!;e, especially 
when it attacks the young inflorescences. The perithecia have 
recumbent, brown, simple appendages. This species appears 
chiefly on various Coni}iositae, Eosaceae (esp. Spiraea U/morin), 
Cucurbitaceae, Geraniaceae, etc. Sorauer reports it as very 
injurious to apple-trees. 




Fl<i. 70. — i^jjliiurothtca conlojnti on Hpiraea iilmuria. The white uiycoliul cuutiliK' 
covei-s every p;irt of the iiifloresceuces. Two siK-cimeiis iire much less dofurmcd 
than the others, (v. Tiibeuf phot.) 



Oidium farinosum Cooke. Attacks young leaves and caly.x 
of aiiplc; il is easily distinguished from the oidium-condition ^^^ 
the preceding species.^ 

Sph. mors-uvae B. et C. The Gooseberry-nuhlew. Is specially 
injuriiius to Jiihrs Urn crisfui and other species u{ JUIhs in 
America. Spraying with a solution of potassium sulphide (J, oz. 
in 1 umHoh water) at intervals of twenty tlays is recommended. - 

' SoiiiiiiT, J/'iliriijia, ISSi). 

- Halsti'il {U.S. JJtjicirlmi III u/ A<iricnllurc, Jirport /or 1SS7) disci ilii.s this 
(liseaHe (Kdit.). 



174 



ASCOMYCETES. 



Sph. epilobii Lk. occurs on Epilohiura (U.S. America). 
Sph. Niesslii Thiira. on Sorbus {Pyrus) Aria. 
Sph. pruinosa il. et Pk. ou Rhus in America. 




oQOOpp 

Fig. 71. — Sphaerotheca castagnei. Epiphytic mycelium on epidermis of Spiraea 
UL'iiiaria. Thi'ee haustoria are embedded in epidermal cells. Two conidiophores 
are shown, from one of which a conidiuni has become detached. A hair of 
Spiraea is shown at one side. (v. Tubeuf del.) 

Podosphaera. 

This genus is distinguished from Sphaerotheca by its upright 
perithecial appendages, which branch dichotomously towards their 
extremities. 

Podosphaera oxyacanthae D. C. Apple powdery mildew, 
also occurring on pear {Pyrus), hawthorn {Crataegus), mountain 
ash {Pijrits Aucujjaria), and medlar {Mcspilus). In America 
this disease is very injurious to apple-cultivation."^ It attacks 
chietly young seedling plants, stunting their growth and causing 
them to lose their leaves. 

P. tridactyla Wallr, This causes injury to leaves of various 
species of Prunus (cherry, plum, and sloe)^ (Britain and U.S. 
America). 

-Account by M. B. Waite [U.S. Department of Ayriculture, Report for 
1888); notes on treatment in Fairchikl's experiments (-Journal of Mycology, vii. 
p. 256), and elsewliere (Edit.). 

■* Halsted Zeitschrift f. Pflanzenkrankheittn, 1895, p. .338) gives as additional 
hosts: Apple, Crataegus Oxyacantha, Amelanchier canadensis and Spiraea (Edit.). 



PODOSPHAERA. 



175 



p. myrtillina Seluib. on leaves of Vacciuluia Mijrtillus (bil- 
berry), V. ulifjinosuiii, ami Umjyetnim nifjrum (crowberry), (U.S. 
America). 

Erysiphe. 

The perithecia contain several asci, each with two to eight 
oval hyaline spores. The appendages are like these of Sphac- 
rothcca, simple and thread-like. 

Erysiphe graminis D. C. Mould or mildew of grass and 
wheal. (iia.>^5 aud cereals, especially wheat, often sutt'er serious 
damage from this parasite. The mycelium appears on the leaves 
as white or brownish spots, generally on the upper surface. 
Colourless conidia {Oidium monUioidcH, Lk.) are produced acro- 
petally in chains. The somewhat rare perithecia have brown 
appendages, and contain eight to sixteen asci, with four to 
eight spores each ; the spores mature in spring as the dead 
leaves lie on the ground. This mildew has intlicted great 
loss both in Europe and America. Dusting the threatened 
crop with " tiowers of sulphur " will 
probably check the hrst stages of an 
attack, but care in destroying infected 
crops is by far the most elective 
preventive. 

Erysiphe martii Lev. This fre- 
<[ueuis variuus Leguminosae (clover, 
beans, vetches, peas, lupines, etc.), 
Cruciferae, and other plants (TJritain 
and U.S. America). 

Er. umbelliferarum De Bary. 
Occurs (ju various 1 'iiilii-liiferae 
(I'.ritaiii). 

Er. communis Wallr. on tobaecd, 
culuceae, raitiliduaceae, etc. (l)ritain and I'.S. America). 

Er. tortilis Wallr. on Comas auiii/uutm (iJritain ami 
America). 

Er. galeopsidis I >. ('. on Labiatae (I'.ritaiu and 
.\iiifi-ii',i ). 

Er. cichoriacearum 1>. ( '. on ('dmpnsiiiie, r.oragim-ae, ami 
also causing eniisiderabh' damage to ciKaimbers (Urilaiu and 
U.S. America). 




Fli;. l-l. — En/iijihe umlitUijtrarum. 
(jermjniitioii of a cuiiidiuia («/;) on 
AiithiiM-t'.i siiU-ctrin. All iittach- 
mont-clisc lia.s been fnrnied, and a 
i;erni-tiil>o lia.s iienctnited tlio epider- 
mis to bffonie the first liaustoriuni. 
(After Ho Hary.) 

also on various iJaiiun- 



r.s. 



176 ASCOMYCETES. 

Microsphaera. 

The peritliecia contain several asei with two to eight spores, 
and tlie appendages have dichotomously branched ends like 
those (if ]'iiihixji]i(i(r((. 

Microsphaera astragali U. C. Occurs on Astragalus glyqi- 
'phyllos and A. virgatus (Britain and U.S. America). 

M. berberidis D. C. on Barberry (Britain). 

M. lonicerae D. C. on species of Lonicera. 

M. grossulariae Wallr. on Gooseberry (Britain and U.S. America). 

M. lycii Lasch. on Lycium, and Desmodmm (Britain and U.S. America). 

M. evonymi D. C. on Etonymus exiropaexis (Britain). 

M. aini D. C. on Alnus glutinosa, Betula verrucosa, and B. puhescenSy 
Rhamnus cathartica, Vihurmim Opulus, and T''. Lantana, etc. (Britain and U.S. 
America). 

M. densissima (Scliwein.)^ This species forms orbicular patches on the- 
leaves of (^nercus tinctoria, etc., in North America. 

M. Guarinonii Br. et Cav. on Cystisus Laburnum. 

Also several other American species. 

Uncinula. 

The perithecia contain several asci with two to eight spores. 
The appendages have involute ends, and are simple or dicho- 
tomously branched. 

Uncinula spiralis B. and C- (U. S. America and Britain). 
The Vine Mildew. This disease was first observed in England 
in 1845, and since then has spread over the whole of Europe. 
The conidial stage has caused widespread injury, but the perithecia 
remained quite unknown till 1892, when they were observed on 
vines in France by Couderc, and in 1893 in large numbers by 
Viala. In America, a similar disease is also well known ; its 
perithecia have been long recognized and named Uncinula 
spiralis. The identity of the American and European mildew 
was first suggested by A^iala in 1887, and may now be assumed. 
The perithecia ^ when mature are brown, spherical, and beset with 

^ Atkinson, BuUetin of Torrty Botanical Club, Dec. 1894. 

- In conseqiience of recent investigations, this species has been transferred from 
the genns Erysipht, and revised with the author's consent. (Edit.). 

Viala, Coinpt. rend, oxix, 1894, p. 411. Prillieux, Bu//. de la Sac. mycol. de 
France, 1893. 

"B. T. (Calloway (Botanical Gazette, 1895, p. 486), gives a recent account of 
the development of this Uncimda. (Edit.). 



UXCINULA. 



177 



appendages having hooked tips. Within the perithecia are 
found the ovoid asci containing the spores ; there are from four 
to ten asci in each peritheciuni, and four to eight spores in each 
ascus. 

The conidial stage was formerly known as Oidiinn Tuchri. 
The conidia are abjointed as oval colourless bodies from simple 
septate conidiophores, to the nundier of two or three in each chain. 
They germinate at once, and as they are formed in large numbers, 
especially in moist weather, the disease spreads rapidly. The 
mycelium is non-septate, or almost so, and attaches itself to the 
epidermal cells of vine-leaves and young grapes, by lobed attach- 
ment-discs, from which simple sac-like haustoria make their way 




Fio. lZ.--L'nei-iiv.la neeris. Perithecia. (Aftor Tuliuiiic.) 



into the cells. The mycelium forms white s])ots, but after a 
time causes the death of cells near it, so that brown withered 
spots appear. The leaves generally wither, the grapes, liowever, 
continue to grow at the jtlaces not attacked, till rupture of the 
coat ensues, then they shrivel u]) or fall a prey to mould-fungi. 
Sulphur is the preventive generally used (See p. 170). 

Uncinula aceris D. C. (liritain). This appears as Nv;hite spots 
on the leaves of .species of Ao); native and cultivated. When 
attacked by this mildew, young unfolding leave.s are stuuteil in 
growth, while older lf;i\e.-< ill autuiiiii still retain their chlon)- 



178 



ASCOMYCETES. 



phyll iu diseased spots, so that when dead and yellow, they 
are still spotted with green. The conidia are oval, so also the 
spores of which six to eight are found in each ascus. 

U. Tulasnei Fuck, produces 



AM 







a white coating over the whole 
leaf-surface of Acer platanoides. 
The conidia are spherical. 

U. circinata C. et Peck, is 
found on species of Acer in 
America. 

U. salicis \). C. (Britain and 
U.S. America). This species 
occurs on leaves of the willow, 
and produces white spots or 
thick coatings on one or both 
surfaces. It is also found on 
leaves of poplar and birch. 

U. prunastri D. C. on Fru7ius sjnnosa (Britain). 

U. Bivonae Lev. on Ulmus montcma (U.S. America). 

Also other American species. 



74. — Uiicinula salicis. Peritheciutn. 
(After Tulasne.) 



Phyllactinia. 

The spherical perithecia are flattened at the poles, and 
enclose several asci containing two or three oval sulphur-yellow 
spores. The appendages 
are sharp-pointed hairs 
with swollen bases. 

Phyllactinia suffulta 
Kebent. {Fh. (jattatd 
Wallr.) produces white 
spots or coatings on the 
leaves of many trees, e.g. 
beech, hornbeam, ash, 
birch, hazel, oak, etc. 
(Britain and U.S. 
America). 




KiG. 7o.--Phi/llactinia suff'ulta on Fagus si/lvatica. The 
leaf is partially covered by a white mycelium, on which 
the perithecia appear as black points, (v. Tubouf del.) 



PERISPORIEAE. 
The Perisporieae include the following genera Thielavia, Dimc- 
rospormm, Majjnusia, Ccphalothcca, Zopjiclla, Anivia, Eurotiuvi, 



PERISPORIEAE. 



179 



Aspc/yillus, PiyiiiciUiuiii, Zopji", Prrispoi-ium, Lasiobotrys, Apio- 
-sporimn, Cupnodium, Astrrina, Micruthij rium. 

To this sub-division of the Perisporiaceae belong some com- 
mon forms of mould-fungi which are generally only saprophytic. 




"i^'^^^ 



Kiii. lil — flti/llactinia »itffultu fnmi Hucoli. Porithcciiiiu, wiUi chftractorlstlc 
a|i|K.'ii(lai;t.'H. ('(jiitcntH of the iiurithwiiim : itscl, sihux-h, iukI chiiitiH of foils 
ruMciiibliiijf iianipliyHcM. (v. Tiibuuf ik-l.) 



but occasionally lind their way into fruit with l)roken epidrrmis. 
They are thus found carrying on secondary decay anil rot, where 
other diseases have begun the attack. 



180 



ASCOMYCETES. 



Ill this group are included certain species of fungi which are 
able of themselves to induce rot in ripe fruit. Davaine ^ was 
the first to direct attention to these, and recently they have been 
made the subject of very searching investigations by Wehmer.^ 
According to this author, only a limited number of species of 
fungi accompany this kind of rot and give rise to it primarily. 
As a rule they effect an entrance by some wound, possibly also 
through lenticels or other apertures. Some forms prefer certain 
species of host-fruit, in some cases even certain varieties. 

Wehmer gives the following synopsis : 



Fruit. 
Apple, 
Pear, 
Medlar, ] 

Grajie, 
Plum,- 



Cause of Ripe-kot. 
[ Penicillium glaucum. 
I Mucor piriformis. 
\{Mucor stolonifer.) 
( Pen icillium glaucum . 
\ Botrytis cinerea. 
^ Mucor racemosus. 
y Pen icillium glaucum. 



Fruit. 
Orange, \ 
Citron, 
Mandarin, j 
Cherry, - 

Walnut, - 



Cause of Ripe-rot. 

I Penicillium italicum, 
j Penicillium olivaceum . 

- Penicilliurii glaucum^ 
i Botrytis cinerea. 
\ Penicillium glaucum . 



He then arranges them according to their occurrence, beginning 
with the most frequent : 

PeniciUium glaucum Link. : on stone-fruits, pome-fruits, grapes, 
walnuts, especially common on apples. 

Penicillium italicum. Wehmer : on southern fruits, e.g. citron, 
orange, mandarin. 

Mucor inriformis Fisch. : on pome-fruits, particularly on pears." 

Botrytis cinerea Pers. : on grapes and walnuts. 

The following are less common species : 

Penicillium olivaceum Wehmer : on southern fruits. 

Mucor racemosus Fres. : on plums. 

Mucor stolonifer Ehreiib. : on apples. 

Eipe fruit should be so treated as to remove risk of infection as 
much as possible. This is done by storing the fruits in airy, dry 
places, and in loose contact with each other. A damp atmosphere 
promotes infection and facilitates the progress of rot. All decaying 
fruit should be separated at once, and valuable fruits are best 
isolated by wrapping singly in tissue paper before transportation. 

'Davaine, " Recherches sur la pourriture des fruits et des vegetaux vivants," 
Compt. rend., i^xiii., 1866. 

-Wehmer, Beitruge z. Kenntniss einlidmischer Pilze, Jena (Fischer), 1895. 



PERISI'OHIKAK. 181 

Species of fungi included in this group are the cause <jf 
those black, sooty coatings found on leaves frequented l>y green 
tiy (Aphis) and other leaf-insects. Thest* are purely epipliytic 
and saprophytic forms which derive nourishment from the 
"honey-dew" excreted l»y the insects.^ They multiply very 
rapidly, and soon form dark coatings on the upper side of 
leaves and twigs. Little damage need be feared, since the 
leaves retain their green colour, and the coating is not enough 
to stop access oi' liglit. Amongst them are species of Caj)- 
luxlium, Meliola, and Apiospurium, as well as the conidial forms 
Fnrnayo, Tonda, Antennaria. 

The modes of reproduction of tlie.se forms are exceedingly 
varied. According to Zopf^ they form: (1) ascocarps; (2) many- 
celled large conidia ; (o) unicellular, very small conidia ; (4) 
isolated and clustered conidiophores ; (5) gemmae; (6) buds in 
a yeast-like manner ; while every fragment of a mycelium can 
produce a new growth. Any of the species may frequent 
many various plants, and can pass easily from <jne host to 
another. Some of the Ijetter-known forms are : 

Capnodium salicinum Mont. (Britain). This occurs on 
S})e(;it's of willow, poplar, hop, and many other plants. 

If it appears early and abundant on hoj) it may cause 
consideiable damage. (Fumajjo carjans is a conidial form). 

C. quercinium I'ers. on oak. (U.S. America.) 

C. taxi Sacc. et Roum. <iii Turns. 

C. foedum Sacc. (spermogonium i'onn = ('hn'tdplionui fixihi). 
<h\ the leaves of oleander. (U.S. Americn.) 

'i'he genus Apiosporium forms similar s(joty coatings. 

A. pinophilum Fuck. Tliis covers with a black coating 
wlioir iwi^s ami leaves of silver fir; the needles however retain 
their "j,reen colour comph^tely. {AntiHiKirid and Turnhi are 
forms of ibis.) 

A. rhododendri l-iuk. ; A. ulmi Kuek. ; and other speeies. 

I'lif iiiiii(li;il form I'l'llicnlaria wliidi produces f^vey (.•oiitiii;.;s on tin- loflVi'- 
jdiiut is Loiisidii til .iiiioiig the Hyphoiiiycetes. 

Species of Meliola also ])roduce sooty coatings. 

M. citri Sacc. ami M. Penzigi Saee. occur oil Citrus in 

' MiiHj^L'ii, I)' r llnni'iihtin. Hiij/n'iisrh'' Stnilint ail /'flitir.'ii. .Iciia (Kischt-r). 
"Zi»|)f, " Die Coiiidieiifriicliti; v. Fiiiiiiigo." .V"fv( ,i<hi, I'.d. »n. .M.su : '/.i>\>f, 
/>iV I'lhf ; Tiiliisiif, S'/frt. fiiiKj., 111. 



182 ASCOMYCETES. 

Soutliern Europe and America. Sooty mould of the orange is 
also ascribed to Ca^modium citri Berk, et Desni.^ 

M. camelliae Catt. on Camellia japonica. According to- 
Briosi and Cavara, this causes drying up of the leaves. 

Stemphylium ericoctoimm Br. et Bary, the " sooty-ilew " of indoor heaths 
is considered amongst the Hyphomyoetes. 

Lasiobotrys. 

L. lonicerae Kunze.- The perithecia form black masses on 
green leaves of species of Lonicara. If these be removed the 
epidermis remains uninjured, except for a slight cavity with a 
lighter green colour than the neighbouring surface. 

Thielavia. 

Perithecia splierical and without an aperture. The asci 
contain eight brown unicellular spores. Paraphyses absent. 
Conidia and chlaniydospores are formed. 

Thielavia basicola Zopf.-" This is the only species of the 
Perisporieae which causes a really serious plant-disease. It is 
allied to the Erysipheae, and produces three kinds of repro- 
ductive organs on the underground parts of plants of Lupine i 
(1) Cylindrical, delicate, hyaline chlamydospores, produced in 
pistol-shaped branches of the mycelium. (2) Thick-walled, 
brown-coated, resting conidia arranged several in a row, like 
spores of a Pliragmidmm. (3) Perithecia, or little, spherical, 
permanently closed, brown structures with ovoid asci containing 
eight brownish lemon-shaped spores. 

A white coating of the hyaline conidia is first formed, then 
a brown coating of the dark conidia, and finally perithecia. 
The mycelium bores through the cell-walls and fills first the 
cells of the cortex, later those of the deeper parenchyma of the 
host-root. The disease of the root soon causes a stunting of 
the shoots and leaves, finally death of the plant. The roots 
attacked are at first brown, then they rot and become detached. 

1 W. G. Farlow, Bull. Bussey Institute, i. J 876, p. 404; Swingle and Webber, 
"Diseases of citrous fruits," U.S. Dept. Agric. Bull. 8. 1896. 

- Jaczewski includes Lasiobotrys with the Cticnrbitariaceae. 

•'Zopf, " Qeber die Wurzellmiune d. Lupinen." Zeitsrhri/t f. Pflanzenh-ank- 
heiten, i. j). 72. 



THIKLAVIA. 183 

The fungus has been observed on Lupinvs anf/i/stifolivs, L. alhus, 
L. thcrmis, Trigonella cotrv.lea, Onohrychis Crufa f/al/i, Pismn 
Hotivvrn, Soucio eleyanfi, and Ci/clamcn} 

Thielaviopsis ethaceticus AVent.- has been given as the cause 
ot" a sugar-caiu' disea.sL' iu Java. 

The Tuberaceae funn a thinl sul>-di vision of the I'erisporiaceae. 
The group includes the Tubereae and the Ehaphomycetes. It 
contains no forms injurious to plants. 

In investigating Elapliomyces (jranvlatiis and E. rarieyatvH, 
Keess ^ found that it not only formed niycorhiza, but was also 
parasitic on the roots of Pinn^i and destroyed them. 



pyrenomyc;etes. 

The ascocarp or perithecium of the Pyrenomycetes is a closed 
structure provided with an opening by which the ascospores 
are discharged. The ascocarp of the Perisporiaceae, as has 
already been pointed out, has no such opening. The inner wall 
of the perithecium is clothed with {a) the asci, {h) delicate fungal 
filaments. Of the latter, those in the depth of the perithecium 
are known as paraphyses, and among them the asci originate ; 
others around the sides and opening of the perithecium are 
the periphyses, which grow inwards so as to close both \n)\v 
and canal. Peritliecia may occur isolated or ma.ssed together, 
and are frecpiently .sunk in a special cushion of fungoid tissue, 
the stromata. 

The Pyrenomycetes may also produce chlamytlospores and 
various forms of pycnoconidia and free conidia ; these also are 
fre(iuently developed on special stromata. According to Prefeld's 
researches, the structures so well known as spermogonia witii 
their contained spermatia are only pycnidia containing eunidia, 
which have in many cases been artificially caused to germinate. 

The Pyrenomycetes include a large number of forms })ar- 
asitic on all parts of living jilants, most of liu-m aie eapal)le 
of e.xisting for some jjart of tiu-ir liws as saprophytes, and as 

' Tliis fungus is dcscrilioil us ciiusiiij:; ii loot rot of Viola oiloratd in I'.S. 
Aniericu (Coiinnt. A</fir. Exptr. Slat. ]{i port for IS'.M). (Kilit.) 

-Went, Archie/ roor di- Jara-Siiikt riinhtsfrit'. iSiKJ. 

' KeesH iiml Fiscli., " Untersucli. ul>. ){iiii u. LfliuiiHgi'siliicliti- il. Iliisdit nitlcl." 
nUiliollina holnii. Heft 7. issy. Witli lUus. 



184 ASCOMYCETES. 

i\ rule they reach maturity only on the dead remains of host 
plants. Many of them are enemies of woody plants, and the 
mycelium of some can live in the elements of the wood itself, 
hence they constitute a dangerous group of wound parasites. 
The Pyrenomycetes may be sub-divided thus : 

1. The Hypocreaceae having soft coloured perithecia often 
placed several together on a stroma. 

2. The Sphaeriaceae with firm dark-coloured perithecia 
frequently embedded in a stroma. 

3. The Dothideaceae with perithecia so embedded in a 
.stroma that they have no distinct wall of their own. 

All three divisions include forms parasitic on plants, 

(1) HYPOCREACEAE. 

The Hypocreaceae consists of a single family bearing the 
same name. Of the seventeen genera contained therein only 
six contain plant parasites, viz. : — Gihherclla, Calonectria, Nectria 
(including Nectriella), Polystigma, Einclilo'e, Claviceps. The re- 
mainder are saprophytic only, and do not come within the 
scope of the present work : they are — Melanospora, Sclinia, 
Elcutheromyces, Hypomyces, Sp)hacrostiIhe, Lctcndraea, Hypocrca, 
Pleoncdria. Barya, Oomyces, and Conlyccps. 

Gibberella. 

The perithecia have a transparent blue or violet colour, and 
form tufts on the stromata. A stroma is not present in all 
the species. The spores are light-coloured, and spindle-shaped 
or oblong. 

G. moricola Ces et de Not. Passerini gives this as the cause 
of a disease of young twigs of mulberry. 

G. pulicaris (Fr.) is very frequently found on tree.-5. (Britain). 

Calonectria. 

The perithecia are yellow or red, and occur isolated or several 
together. The asci contain spores composed of three or more 
cells, rarely of one cell. 

C. pychroa Desm. causes death to young leaves of planes 
(esp. P. occidentalis) ; it also multiplies by means of conidia 
{Fusarium platani). 



NECTRIA. 



185 



Nectria. 

Perithecia yellow or red in colour, and generally produced 
in close tufts on stromata of the same colour. The asci con- 
tain eight bicellular spores and few or no paraphyses. Conidia 
of various kinds and shapes are also produced. 

Nectrina cinnabarina Fr.^ (Britain and U.S. America). The 
bright-red, button-sliaped conidial cushions of this fungus may 





Fi"i. 77.— .Wet ria ciiiii"i>iii-,,"i , witli peri- 
tliucia on the dead bark of a still-liviii); 
HtfUi of Elm. Infection has evidently 
beifun at the wound of a cut branch near 
the middle, and extended outwardH. (v. 
TuU-iif i>hot.) 



Km. 7S.— .Vn-dKi oi.(/i<('«(;i,i((. I'.iitmn »i 
hnmcli (magnified). Lit^ht-coloured eushionii 
of conidiophores with conidia are breakint; out 
towards the upper end, and colonies of iiard 
red perithecia towai-ds the lower end. (After 
Tuliisne.) 



l)e found aliUD.st at any lime on llie dead Iirauclifs of many 
dt'cithious trees, '■.//., Aisrulux, Am-, Tilin. Murns, UhnuK, etc.; 
als(j on Lijiiuym, SninJ)iicus, Jiulii/iin, and Pi/rns, in America. - 

' Tiiliisne, Si bit fmii/., 1H65. 

- Bell reus (Ztitxfh. /. I'lUmzmkraiikhi itm (l89.'») iisoiihes to X>rtrin the very 
<;<>iiin)(in tuberouH swellin^M on tlie twigs of AhiiH hnlxaniKt ; these, however, 
inuy iiriHC without the agency of the fungus. 



186 



A.SC0MYCETE8. 



The dark-red masses of thick-coated, warty perithecia appear 
in autumn and winter on the dead branches only ; the asci 
contain eight bicelhilar hyaline spores which germinate 
directly to form a mycelium. Infection of a new host-plant 
is effected by the mycelium, which enters by open wounds into 
living branches ; it is quite unable to penetrate the living 
bark and is dependent on wounds. The mycelium spreads 

rapidly through the tissues of 
the host, especially through the 
vessels of the wood ; the cam- 
bium and' rind are not attacked 
directly, but are killed in conse- 
quence of the destruction of the 
wood.^ The regions attacked 
in the wood appear as greenish 
stripes, and withering of leaves, 
followed by death of branch 
after branch, results in conse- 
quence of the growth of mycelium 
in the water-conducting elements 
of the wood. 

For protection against this 
and all other parasites, which 
find entrance by wounds, it is recommended to prune or dress 
trees only when necessary, and to paint all wounds with tar 
or tree-wax. This Ncctria is one of the commonest parasites 
of our parks and fruit gardens, hence all branches already 
attacked should be removed and burned, likewise all blown 
timber which might serve as a nursery for production of 
spores or conidia. 

Nectria ditissima Tul. (Britain and U.S. America). This 
is a common parasite and a frecj^uent cause of the canker of 
beech, apple, and other trees.- The mycelium lives chiefly 
in the bark, causing it to die and form cracks. Under 
ordinary conditions all cracks and fissures are occluded or 




Fig. 79. — Nectria cinnaJjo.rina. Enlarged 
section of perithecial colony. Germinating 
ascospores. (After Tulasne.) 



' Mayr in Hartig'.s Uvtersvrh7i.iigen a. d. /orsi-hofan. InMitut zn Miinchen, iii. 
Berlin, 1882. Brick, Arheiten d. bolan. Museums, Hamburg, 1892. 

Wehnier (Zeitsch. f. PflanzcnkranhJidten, 1894 and 1895), opposes Mayr's con- 
clusions and holds that Nectria can penetrate intact, living bark. 

-Goethe, " Ueber Krebs d. Apfelbiiume. " Bhein. Blatt f. Obst., Wti)!, v. Gar- 
tetihaii, 1879. R. Hartig, Unttrsiich. aus d. forst-hofan. Iiisfitut. 7.u Miinchen, i. 



NEOTRIA. 



187 



grown over in course of time by the activity of neighbour- 
ing living tissues, but the rapid development of the mycelium 
of this Nrctria prevents any such healing, and brings about 
death of more liark. As a result the so-called " cankers " are 





Kio. Ml. — Sertr'iii iiiti».uina. Caiikci- 
oil u xtcin of Beech, (v. Tubcuf 

phot.) 



Ki(.. H\.—Nicti-iu tlitifs,,.-. I .iiKi 11)11 ll:izcl. The 
\Ancf of infection, i\ jmrtially broken branch-fork. 



prtjdiicfd. Thf mycelium at first gives oil' liny uiiicclhdar 
conidia mi the liaik, then later while eu.shiim.s bearing line 
eonidiopJKjre.s, from whieh are abjoinled multicellular cduidia, 
sliaj»ed like a sickle. Ini'eclinu i.s lirouglit about by the 
geiniinatinn of spures or conidia on wounded ]iarts of tin.' 



188 ASCOMYCKTES, 

bark,i and even on young unfolding leaves. The red lemon- 
shaped perithecia break through the bark as compact patches. 
They are distinguished from the perithecia of N. cinnabar ina 
by their smooth exterior and their smaller asci and asco- 
spores. 

Combative measures to be used are plentiful dressing of 
wounded places with tar, and the burning of all infected 
material. 

Nectria cucurbitula Fr.'- (Britain and U.S. America). This 
parasite on conifers generally, is particularly injurious to spruce 
(Ficea). It enters the host by wounds, such as those caused 
by the caterpillars of the spruce moth {Grapliolitha padolana), 
or by hail. The mycelium lives chiefly in the bark and bast ; 
during the active growth of these tissues further extension of 
the mycelium is almost completely hindered by the formation 
of a secondary cork, but in the resting periods of these tissues 
of the host, new hyphae are rapidly produced, lleproduction 
is brought about by little unicellular, and larger multicellular 
sickle-shaped conidia produced on conidiophores. The mycelium 
frequently proceeds as soon as formed to give off the smaller 
variety of conidia. The dark-red perithecia are produced later 
on the same stromata as the conidia. The asci contain eight 
l)icellular spores ; the paraphyses are very delicate and slightly 
branched. 

The fungus sometimes occurs epidemic in spruce plantations, 
and may be the cause of many deaths. According to Magnus, 
the larch and cembran pine may also be attacked. As a pre- 
ventive measure all dead parts should be cut out and burned. 

Nectria Rousseliana Tul. lives in and kills leaves of the 
box (Biwus). 

Nectria pandani Tul.^ is said to be the cause of a disease 
on P(iii(l(iiuis, als(j ascribed to Mdanconium j^afidu'ii. The 
Pandanus disease has been reported from the Botanic Gardens 

' Young forests in districts subject to hailstorm, (e.;/. on the lower Alps 
of Bavaria), may become completely infested with Nectria through hail-wounds. 
(Edit.) 

- R. Hartig, Unter-mch. cms d. J'orst-botaii., Iwititut. i., 18SS. 

•'Schroeter ("Ueber die 8tammfaule d. Pandaneae," Cohn's Btitr. z. Biol. d. 
I'Han-j'n. Bd. i., 1895) suggests that this M'lanronium is a conidial form of 
Xectria. During the investigation of a case of a Paiidanwi killed in the Palm 
House at Edinburgh Botanic (iarden, .J. H. Burrage found both forms present 
an I agreeing in order of development with Schroeter's observations. (Edit.) 



NECTKIA. 



189 



of Breslau, Berlin, Paris, Kew, Glasnevin (Dultlin), and 
Edinburuli. 

Nectria ipomoeae Hals.^ Stem-rot of egg-plant and sweet 
potato. In America this attacks young growing plants, and 
causes stem-rot. The Fi'saj'inm -stage developes as a white 
mouldy coating on the withered stem, and is followed later 
by Hesh-coloured clusters of perithecia. 



Poly stigma. 

On the leaves of species of Frunns, one finds bright-coloured 
spots, these are the stromata of this family, and in them 
are emljedded pycnidia containing hook- 
shaped conidia. Perithecia emljedded 
in a similar manner are developed 
after the fall of the leaves, they contain 
asci with eight unicellular elliptical 
spores, which are expelled on reaching 
maturity in sjiring. 

Polystig-ma rubrum (IVrs.) (Britain 
and U.S. America). This appears as red 
circular spots on the leaves of plum and 
sloe. Micropycnidia are developed in 
summer on the under-surface of the leaf 
and give rise to curved conidia. Tiie 
perithecia begin their development in 
summer, but only reach nuiturity in the 
following spring, after the leaves have 
fallen from the tree and lain on the 
ground over winter. The asci are clul>- 
.shaped, long-stalked, and contain eight 
spores, which are set free in succession 
from April to June. Germination ensues 
on young leaves, and in six weeks 

pycnidia reappear. A variety, '' Ami/tjdtili l)esui.," is found vw 
the leaves of the almond {Aiiuiydalvs communis). 

Frank and Fisch found in connection with 1'. riihnim, 
certain hypliae which they designate as trichogynes, while 
they regard tin- small form of conidia as sja'rmalia which 

' Description mid illnstnitioii.s in X. J< rs, ij Aijrir. Erpfr. Station Jfe/iort, ISIM. 




Klo. S'2. — Poltittigttiu rubnou 
on a kiif of Plum. The laive 
Iiriijeotinj: rod spots contain peri- 
tliL'iia and sininiogonia. Dtirk 
lir.nvn jiiitihcs ..f Puceinia /.nnii 
iirciilNoshown on the upper jmrt 
of the leaf. (v. Tubeuf del.) 



190 



ASCOMYCETES. 



fertilise the trichogyne and cause it to develop as an 
ascogonium. 

P. ochraceum (Wahlenb.) (P. fulvicm D. C.) causes yellowish- 
red spots on leaves of Fric/iics Padus. 

P. obscurum Juel. produces thickened leaf-spots on Astragalus 
alpiiiiis and A. orohoidcs ; on the under side these are whitish, 
on the upper side they show the spennogonia as red points. 

The damage caused by Polystigma is easily kept in check 
by burning infected leaves in autumn. 



Epichloe. 

The stromata form on the stems of grasses yellowish mould- 
like coatings in which the flask-shaped perithecia are embedded. 




Fig. 83. — Epichlo'i iyphina, forming numerous white cushions, which completely 
encircle the grass-stems, (v. Tubeuf phot.) 



The asci are cylindrical, and contain eight thread-like unicellular 



Kl'irHLOii. 191 

spores. The formation of perithecia is preceded on the same 
•stroma by that of coiiidia.^ 

Epichloe typhina Tul. (Britain and U.S. America). This 
may be I'uiind un many grasses as a mouldy coating which 
surrounds the haulms and causes withering of the parts above 
it. The fungus not unfrequently attacks such fodder-grasses as 
Dactylis, Poet, and PJilcum pradense, causing severe loss where these 
crops are much grown. On the white stromata conidiophores are 
produced, and from them small, ovate, unicellular conidia are 
abjointed. These are followed later by perithecia embedded in 
the same stromata. The asci, of a somewhat yellowish colour, 
are long with button-shaped apices and contain eight thread- 
like spores. 

Ep. Warburgiana, Magii.- is an interesting species found (Ui arrowroot 
{Mariiata') in tlie Philippines. 

Claviceps. 

The sclerotia are black lioru-like bodies, and on them the 
stromata are developed as stalked structures, with spherical 
heads, in which the tlask-shaped perithecia are embedded. The 
asci contain eiuht ihread-like spores. 

Claviceps purpurea (Fries^) (Britain and U.S. America). 
This fungus becomes most apparent, when in the stage of 
the well-known "Ergot" grains, bluish-black curved sclerotial 
bodies in which the mycelium perennates over winter. Ergot 
is found in the ears of our cereals, especially in rye, also in 
other cultivated and wild ( f ramineae. The sclerotia fall into 
the ground direct, or are sown out with the seed, and in 
spring or early summer produce a large number of stromata, 
eacii consisting of a violet stalklet carrying a reddish-yellow 
head. The ovoid perithecia are completely Inn-ied in the liead 
of the stroma, and contain the asci, each witii eiglit threatl-like 
ascospores. The spores, after ejaculation, germinate on flowers 
of (Iramineae, and the septate mycelium developes in the outer 

'.Atkinson, (J. F. (Ton-eij Clnh BuUilin, 1894, p. •_*2i), pioposi-s :i revi.sion 
of the species of E/iirh/oi; and otlur species of X. American ^'latninocohniH 
llyitorrtartai'. ( Kdit. ) 

-. Magnus, Indntut. Hot. (Jonijrtsa, 189*2.' 

'Tulasne, Anitnl. il. nri. nalnr. 3 ser. xx. Knhii, Mitth> i/uii'/> ii tl. Innd- 
ii-irth. IiiMflhtl. Huile, lS(i.'{. 



192 



ASCOMYCETKS. 



coats of the ovary, till gradually but completely it tills up the 
whole cavity. Outside the ovary the mycelium forms an 









L 



I'ln-purea. Err/ot. Sckrotia or Ergot-grains in ears of Rye. 
(v.^Tubouf phot.) 



irregular wrinkled white stroma or sphacelia, from the hollows 
and folds of which little ovoid conidia are abjointed from short 



CLAVICEPS. 



193 



conidiophores. A very sweet fluid, the so-called " houey-dew," 
is separated from the sphacelia ; this attracts insects, which 
carry the conidia to other flowers. Since the conidia are 
capable of immediate germination, and give rise to a 
mycelium which penetrates through the outer coat of the 
ovary, the disease can be quickly disseminated during the 
flowering season of the grasses. After the formation of conidia 
has ceased, the sclerotia become firmer, with a dark wrinkled 
cortical layer and an internal firm-walled pseiidoparenchyraatous 




Fia. So.—Ctaviceps jmrpurea. .4, Sclerotiuin with seven stromata (cl). H, 
nicdi;iii loiigitiidin;il section through the upper part of a stroma, the flask-shai>ed 
peritliecia (f//) are embedded in the head. C, Perithecium in longitudinal sectiim 
(highly magnified)— /<(/, hyphal tissue ; sA, cortical tissue of the stroma ; f/), orifice 
of the perithecium. D, Isolated a.scus ruptured, so that the thread-like a.sco- 
spores (*/j) have begun to escape. (After Tulasne, from Sach's Lehrlntch.) 



liy})hal tissue. In this conditimi they are introduced aliui'^ with 
grain into l)read, which wlien eaten acts as a powerful poison, 
producing very serious results (Krgotism). Tlie sclerotia are 
also used medicinally, and are collected for this purpose {Scro/e 
cor a lit inn). 

Kohert (FriJlmer, Lehrhnch der To.iiiiofoi/ie fiir Tliienirtze, 18!)0) .state.s 
that Ergot coiitaiiis three poisonous ai^'eiits : 

(1) CoriiKtlit, an alk.iluid wliirli iModiic-es tliat j)arli<nlar etVeet of er;,'ot 
in cauHii)<( contraction of the uterus. 

{'!) Sfiluuelic (icid, a non-nitro<,'enous, resinous, non-<i ystalli/alile suit- 
stance, insohilile in water ami dilute arids, l»ut solulile in alcMhol, and 

.N 



194 



ASCOMYCETES. 



forming, with alkalies, salts soluble in water. This is the real cause of 
ergot poisoning and gives rise to gangrene. In large doses it produces 
cramp similar to strychnine, and tetanus of the uterus. 

(3) Ergotic acid, a nitrogenous, easily decomposed glycoside, which has 
no eflfect on the uterus. It is more a narcotic which diminishes reflex 
excitability and finally stops it. 

Robert experimented chiefly with cattle and fowls. He found that an 
acute course of the poisoning can be distinguished from a chronic ; also a 
gangrenous ergotism from a spasmodic. The symptoms of the disease are : 

(1) Gastro-enteric, an excessive salivation accompanied with redness, 
blistering, inflammation, wasting and gangrenization of the mouth-epithelium; 
similar changes also occur on the epithelium of the gut, producing vomiting, 
colic, and diarrhoea. 

(2) Gangrenization and mummifica- 
tion of extremities, consisting of a 
drying-up, a dying-off, and a detach- 
ment of extremities, such as nails, 
ears, tail, wings, claws, toes, and point 
of tongue. 

(3) Spasmodic contraction of the 
uterus and consequent abortion. 

(4) Nervous phenomena such as in- 
sensibility, blindness, paralysis, etc. 
The presence of ergot may be de- 
tected both microscopically and spec- 
troscojncally. 

The fungus may be combated 
by careful separation and de- 
struction of sclerotia, and by the 
use of clean seed.^ 

Claviceps microcephala 
( Wallr.) (Britain). Tliis is found 
on Phragmites, Molinia, Nardus, 
etc. It . has smaller sclerotia, 
which, according to Hartwich,^ 

on Molinia coerv.Ua. (v. Tubeuf phot.) LOnUUn unice UimCb clis mucil 

Ergotin as those of CI. ijuriyurca. 




^ Smith {Diseases of field and garden crops. 1884. p. 233) describes and 
figures Claviceps purpm'ea var. Wilsoni on Glyceria fluitans near Aberdeen. It 
is distinguished " in being whitish or yellowisli, instead of being pale purple in 
colour, and in the perithecia or conceptacles being almost free on an elongated 
club-like growth instead of being immersed in a globular head or stroma." 

-Hartwich, " Sclerote du Molinia coerulea." Bullet, de la Soc. iMycolog. de 
France. 1895. 



CLAVICEPS. 195 

CI. nigricans (Tul.) on Hdeueharis and Scirpus, with sclerotia 
of a (lark \iulet colour (Britain). 

CI. setuloso (Quel.) on Poa. Strumata straw-yellow in colour. 
CI. pusilla Ces. on Andropogon Ischaemum. 



(2) SPHAERIACEAE. 

The group of the Sphaeriaceae includes eighteen families, 
but only the following contain parasites of interest to us. 

Families : Tricltoifphaericae, Mclanomeac, Amp)hisphacri€ae, 
Cucurhitaricae, Sphacrclloideac , Fleosjjoreac, G^nomonieae, Valseae, 
Diatrypeae, and Melanconidear. 

TRICHOSPHAERIEAE 
(including C'oleroa and Ht'rpotrichia). 

Coleroa. 

The perithecia have thin walls with radiating bristles, and 
sit superficially on the suljstratum. The asci have thickened 
apices, and contain tiuht two-celled, faintly coloured spores. 

Coleroa chaetomium Kunze, (occurs on living leaves of 
Ruhus rar.sius and Ji'. Idaeiis. In addition to perithecia, it 
forms ciiiii<lia known as Eioqjorium rubi Xees. 

C. alchemillae (irev. (Britain and U.S. America). On leaves 
of Alchemilla nilr/aris. 

C. andromedae IJehm. On leaves of Andromeda poUfolia. 

C. potentillae Fries (Britain and U.S. America). Leaves of 
PijtnitUld (iiisivind. It forms perithecia which are situated 
on the leaf-ribs : also conidia (Marsonia potentillae). 

C. subtilis Fuck. On leaves of Potentilla cinerea. 

C. circinans Fries. On leaves of Geranium rotmidifolwm and 
G. mull'. 

C. petasitidis Fuck. On leaves of I'liasitcs oj/ieinalU. 

Trichosphaeria. 

l't;rilht'cia small, s})herical or uvoid, and more or h-ss hairy. 
I'araphyses distinct. Sjjores with one, two, or four cells. 

We tjive this <,'enus a wider H(<hic than W'iiiiti , .iml iinhidi' s|ieiie.s with 
one, two, ami fipur-ct-lieil .s|ii.res of h\aliiic n|- li^jlit eoliMir, and whotte 



196 



ASCOMYCKTES. 



othei' characters coincide ; this seems to be all the more justifiable since 
one finds on the same species asci with spores made up of one, two, or 
four cells. 

Trichosphaeria parasitica Hartig.^ (Britain and U.S. 

America.) Everywhere in young naturally regenerated woods 
of silver fir, especially in damp places or where the plants 
are crowded, one finds partially browned needles hanging 
loosely from the twigs, held only by a fine white mycelium 
(Fig. 87). In addition to this, one finds in spring young 
twigs completely enveloped in mycelium, with all their 




Fig. ST. — Tnchosphaeria parasitica on Silver Fir. The withered and dead 
needles hang loosely downwards, attached to the twig only by a white mycelium, 
(v. Tubeuf phot.) 



needles killed, so that the twig itself soon dies. The white 
mycelium grows especially on the under side of the shoot, 
and on the lower epidermis of the horizontal needles. A 
pseudoparenchyma, consisting of layers of mycelium, is there 
laid down, the lowest layer of hyphae sending short cone- 
shaped haustoria into the walls of the epidermal cells (Fig. 88). 
Inside the needles, occupying the intercellular spaces, there 
are numerous branches of septate hyphae, which kill the cells 
of the leaf. The perithecia occur here and there on the 
mycelial coating outside the leaf; they are spherical and 
blackish, with radiating hairs. They contain paraphyses and 

1 E. Haitig, " Ein neuer Parasit d. Weisstanne. " Alley. For.st.-ii. Jayd- 
Zeiluny, Jan., 1884. 



TRICHOSPHAERIA. 



197 



asci, the latter with eight four-celled light-grey spores, which 
germinate directly and distribute the fungus over new host- 
plants. 

I found this same fungus on Tsuga canadensis ^ at Baden- 
Baden, and on spruces in several parts of the Bavarian forests.- 
It, however, rarely attacks spruces, although they often occur 
in the same forest with firs. One of the cases of infection 
referred to above was caused by the diseased branch of a fir 
lying in contact with a twig of the spruce, so that the mycelium 
grew from the one to the other ; the spruce needles were killed, 
and woven on to the twig by hyphae. 




Fig. S8. — Trichosphaeria jmraiilica. Mycelial cusLion on lower side of Fir 
needle, a, Fil.imentous mycelium, which, at l>, sends downwards numerous 
brunches to produce a cushion of parallel hyphae, c Where tlic mycelium rests 
on the epidermis, rod-like haustoria are sunk into the outer wall of tlic epidermal 
cells, • t ; (/ shows the mycelial cushion slightly detached from tlie epidermis, so 
that the haustoria have l)een withdniwn. / /, Epidermal cells tilled with brown 
contents. ;/ </, Chlorophylluus mesophyll, which becomes brown after the 
mycelium has ])enetnited to it. i, (Juter court of a stoma tilled by a mycelium 
with nil haustoria, but adhering to the waxv granules of the stomatal aJKjrtui-e. 
(.^fter a. llartiK) 



In woods of young silver fir naturally regeneratetl, this fungus 
cau.ses great damage by killing numerous twigs. It occurs every- 
where in young fir forests, r.t/. the Alps, Bavarian ftire.sls, the 
Black Forest, etc. (Jn dry airy situations, on free-standing 
trees, and on the highest branches of a tree, it is rarely present. 

' V. Tubeuf, lififrdt/t -.. Ktnii/ii. il. Ihnnitkrankhtittn, Ik-rliii (SprinjjtT), ISS.S. 
-V. Tulieuf, " Tiichospliiicria paiiisitii':! dtr Firlite." linlnn. CmlnUli/att, 
XU., 1.S90. 



198 



ASCOMYCETES. 



Its injurious effects can be minimized by removal of attacked 
branches. 

Trichosphaeria sacchari Massee, is regarded as a dangei'ous wound 
parasite of cane-sugar in the Antilles ; it seems to obtain entrance chiefly 
by the canals left by a caterpillar.^ 



Herpotrichia. 

The smooth dark perithecia bear long brown hairs, which 
do not stand erect and stiff, but are more or less prostrate. 




Pig. 89. — Herpotrichia niiira on a branch of Pinus raontana. The ends of the 
twigs, with most of the younger needles, are still green ; the others are dead and 
felted together by hyphae into a black mass. (v. Tubeuf phot.) 

The asci contain eight spores, at first generally two-celled, later 
becoming four-celled. 

^Masses G., Annals of Botany, 1893, p. 515. 
Barber, "Experimental Cultivation in St. Kitto," Leeward Islands Gazette, 
1894. 



HERPOTRICHIA. 



199 



Herpotrichia nigra Hartit,'.^ This parasite is distinguislied 
by its grey inyceliuui, which covers and completely envelops 
twigs and young plants. On the dwarf mountain pine it is 
not uncommon to find branches bearing patches of blackened 
needles closely bound together by gossamer threads, the other 
parts remaining still green and forming a background against 
which the blackened masses show up prominently (Fig. 89). 
Young spruce plants under a metre in height and the lower 
branches of taller trees are frequently completely enveloped in 
mycelium, and, where they have been pressed down to the 
ground by weiglit of snow, the twigs may be woven round 
and fastened to the earth by a felt of mycelium. 




Fui. 90. — Ihrpotridiia nigra, a, liy|ihuu weav- 
ing a granular mycelium on the surface of the 
needle and forming tuber-like bodies over the 
stomata ; rod-like haustoria are sunk into the 
outer walls of the epidermal cells. (After I{. 
Hartig). 




Fio. 9l.—H<ri>otricMa Hi'j/rn. Ascus with 
germinating spores, (v. Tubeuf del.) 



I have fre(|uently observed the fungus on Junipcnis com- 
munis, especially in bavarian forest-land, and on Junipeni^ 
nana in the Alp.s. Trofessor I'etcr found it (ui tlie latter 
host in Sweden. 

The spherical dark-coloured perithecia arc cuvcred with 
prostrate hairs, and contain asci with eight I'oiu-eelhMl spores. 
The spores germinate directly to hyphae. The mycelium closely 

' R. Hartig, '* Heri)otiichia nigra." Alli<i. Fur^l.u. ./(k/iIZ' ifuwi, ISSS. 
V. Tiiheuf, " Mittlieihiiig iib. t^iiiige I'ciiiili- A. Wiililes." Alhij. Ftir.il.u. 
JwjdZtitnwj, IS«7. 



200 ASCOMYCETES. 

envelops the needles and sends out haustoria similar to 
Trichosjyhaeria 2^(^i'^'<^isitica (Fig. 90). 

Herpotrichia is, in high-lying situations, a very dangerous 
enemy of young spruces, and nurseries in such places have 
frequently to be abandoned owing to the death of all the 
plants. Serious damage also frequently results in young planta- 
tions where snow lies long and keeps the young trees pressed 
down towards the earth. Then the fungus, even under the 
snow-covering, weaves round and fixes the shoots so firmly 
together, that only the healthy ones are able to free themselves 
again and to resume their growth in spring. 

As preventive measures, nurseries should not be established 
in high situations, nor in valleys where there is a large snow- 
fall ; while in localities liable to attack, the planting of young 
trees in basins or cups (hole-planting) should be avoided. The 
loss from crushing-down by snow may be lessened by laying 
trunks and branches of felled trees amongst the young plants, 
and by going over them in spring, raising up all prostrated 
plants. 

MELANOMEAE. 

Rosellinia. 

The perithecia generally occur in numbers together ; they 
are black, and smooth or studded with bristles. The asci 
contain eight oval, spindle-shaped, dark-coloured, one-celled 
spores. Filamentous paraphyses are always present. 

Rosellinia quercina Hartig.^ The oak-root fungus. This 
fungus lives in the roots of oak seedlings one to three years 
old, and causes the leaves and shoots to become pale and to 
dry up. It spreads only during damp weather, esj^ecially 
in June, July, and August. In wet years it may cause very 
serious damage, especially in seed-beds. The mycelium pene- 
trates into the living cells of the root-cortex, extending even 
to the pith. At first the mycelium is hyaline, but later it 
darkens, and the hyphae become twisted together into spun 
thread-like strands — the rliizoctonia. These structures apply 
themselves to roots of neighbouring plants, and soon enclose 
them in a weft of hyphae ; by , this means the disease is 

' R. Hartig, Untersurh. au-n d. forstliotan. Ins/itut zu Mi'tnehen, Berlin, 1888. 



ROSELLINIA. 201 

propagated through the soil from plant to plant. There is a 
resting-stage in the form of chambered sclerotia, black tuber- 
like bodies which have their origin in the cortical parenchyma 
of the roots and break out through the cortex. Reproduction 
is effected throughout the summer by means of conidia, pro- 
duced from a mycelium which vegetates on the surface of the 
soil ; this mycelium bears conidiophores with whorled Ijranches, 
from which the conidia are abjointed. 

The perithecia are spherical structures composed of hyphae 
with walls which swell up in a gelatinous manner. At first 
the inside of the perithecium is a gelatinous mass containing 
the paraphyses and the rudiment of the ascogonium. As the 
asci are developed, they push their way into the gelatinous 
mass amongst the paraphyses. Each ascus is a long club- 
shaped tube, the apex of which is thickened and stains blue 
with iodine, showing at the same time a canal piercing it. 
The ascospores are canoe-shaped with sharp ends, and when 
mature have a dark brown colour. Tlie spores germinate in 
spring ; in water-cultures germ-tubes are emitted twenty-four 
hours after sowing. The spores open by a longitudinal slit, and 
a germ-tube emerging from each end branches into a mycelium 
which soon takes on the form of a rhizoctonia-strand. Infection 
takes place through the tender non-cuticularized apices of roots. 

The fungus may be combated if diseased portions of seed- 
beds are isolated by means of trenches dug round tliem. If 
boards soaked in carbolic acid or coal-tar are placed upright 
in the trenches, greater certainty will be secured that the 
disease does not spread. 

Several species of liliizodonw, probaldy related to the above, 
may now be ])rit'Hy considered. 

Rhizoctonia violacea Tul.' ( 1 •■'^- Anu-rita). KnoL-fungus of 
lucerne and clover. The presence of tliis disease is shown in 
summer by the plants withering, and finally dying. The mycelium 
lives inside the roots, and covers them externally with \ioli-i 
coatings on which the sclerotia appear as black tuln-rs. 

On plants with sclerotia, Fuckel fuuml pycnidia ami iKTitliccia nf 
Ij^jttoiphaeriu (Treimttottphaeria or DifH^otliecium) virdiuinn ; wlittlicr tlu> 
various forms wen- related ruiiM not, however, he determined. 

' lloxtnip, I'niln-Kin iji 111 r aiiijaui mil Srriiii/n ^/in i/ti n lihi-.in-lonin, Issti. 
'riilii.sML", f-'uii'ii /ti/jioijati, PI. IX. anil X.\., jsr)!. 



202 ASCOMYCETES. 

The disease spreads through fields in a centrifugal direction 
from a starting-point. Besides the above plants, it is also 
said by Klihn to attack carrots, sugar-beet and mangolds, 
fennel and potatoes ; and Tulasne gives asparagus and red 
clover as hosts. Prunet ^ believes that the fungus remains 
three years in the soil, and recommends that diseased fields 
should not be cropped with lucerne or clover for several years. 
He also advises the isolation of infected land by surrounding 
it with a deep trench in which sulphur is strewn, then covered 
over with soil. The enclosed plot should next be deeply 
trenched between June and August, and all plant-remains 
removed and burnt. 

Rh. crocorum D. C.^ The Saffron destroyer. This parasite 
attacks and kills corms of the saffron {Crocus sativus). The 
mycelium finds entrance by the stomata of healthy corms, 
and covers them externally with a web of violet- coloured 
mycelium. 

Rh. solani Kuhn. occurs as black sclerotia on the skin of 
potato-tubers. 

Rh. batatas Fr. occurs in America on sweet potato. 

Rh. allii Cirrev. occurs on tubers of shalot {Allium ascalonicum) 
and onion {A. sativum). 

Rh. betae Klihn is said to attack beet-root in America.^ 

We may also consider at this place : 

Dematophora necatrix Hartig.^ The vine-root fungus. 
This parasite causes a very destructive disease of the vine, 
and is often confused with attacks of the Phylloxera-insect. 
It occurs in the United States, and is common throughout 
France, Switzerland, Italy, and South-west Germany, being 
known under a variety of names.^ Occasionally it has been 
known to attack the roots of fruit trees and other plants 
cultivated in vineyards. 

' Prunet, " Sur le Rhizoctone cle la Luzerne." Compt. rend., Paris, 1893. 
Fr. Wagner, " Das Vorkommen des Wurzelttiters d. Luzerne." Zeitsch. d. 
Landivirth. Vereiu in Baytrn, 1894. 

-Prillieux, "Sur la maladie des Safrans." Compt. rend., xciv. and xcv. 
Tulasne, Fungi hypocjaei, PI. VIIL, 1851. 

■^ Iowa Afjric. Exper. Station, Bidletin 15, 1891 ; with illustrations. 

■• R. Hartig, Unterauchnnge^i aiis d. forMhotan. Institnt zii Alunchen, iii., 1883. 

^ Wurzelpilz, Weinstockfaule, Pourridie de la Vigne, Pourriture, Blanc des 
Racines, Blancjuet, Champignon blanc, Aubernage, Mai nero, Morbe bianco, etc. 
(Hartig's Lehrbwh). 



DEMATOPHORA. 



>03 





Fio. 93.— Vine-root with rows of black 
sclerutia exposed, aiui beariiij,' bristle-like 
coiiidiophores here and there. (After R. 
Hartig.) 



Fi'j. !»'J. — Vine-ntotk with IhmiHopUora necatrU 
(after u prolonffcd Mtiiy in ii nioiHt chiinber). a, Filii- 
mentoiiH riiyculiiini paHidnK over Into rhl/.o«ti.iil«- 
HtnindM (/-), which .iniintonioHe ut r i-. ./ mid ., 
Uhi/oninri.hM KTowixi^ outward- fn.m the interior. 
(After a. Ilurtljf.) 




Kkj. iM. — I'ortlon of KIg. US after (or- 
iiiiition of conidiophorcN. \ *. (After 
H. IlurtlK.) 



204 ASCOMYCETES. 

Bcmato'plwra forms fine rhizoctonia-strands which grow 
through the soil from root to root. The mycelium kills the 
fibrous rootlets, and spreads from these into older roots to 
form rhizomorph-strands, which, however, have a structure 
quite distinct from those of Agaricus mellci's. The rhizomorph- 
strands may pass out of the root into the soil, there to form 
a filamentous mycelium, or, remaining in the root-cortex, may 
produce rows of black tuberous sclerotia which on maturity 
break out to the exterior. On the sclerotia, or other parts 
of the mycelium, bristle-like conidiophores may be developed 
as branched panicles from which ovoid colourless conidia are 
abjointed. 

This enemy of the vine is rapidly assuming great import- 
ance. Thus, for instance, in Baden/ there is no Phylloxera, 
but whole tracts of vine land are infested with DematojjJiora. 

According to Yiala," Dematojjhora forms perithecia, which, 
however, only develop after artificial culture for several years 
on decayed plants. If this be so, the fungus should be classi- 
fied between the Tuberaceae and the Elaphomycetes. Berlese,"^ 
however, contests this view, and regards it as nearly related 
to Rosellinia. 

Hartig * suggests impregnation of the vine poles with creosote 
as a means of combating this disease. 

Strickeria. 

Strickeria Kochii Korb. develops its peritliecia on the cortex of living 
Rohinia Pseudacacia ; its parasitism is however not yet fully established. 

CUCURBITARIEAE. 

Gibbera. 

The black perithecia, beset with stiff bristles, are developed 
in large groups on a dark pseudoparenchymatous stroma. 

Gibbera vaccinii Sow. (Britain). In damp situations amongst 
moist patches of Hypnmri and other mosses, one often finds 
the cowberry {Vaccinium Vitis-Idaea) with its leaves and 

' Beinling, Z>a.s Anj'trefen v. Rehenkrankheiten in Baden, 1891. 

^Viala, Monographic du Pourridi4 d. Vvjnes, 1891. 

'Berlese, Rivisfa di 2)afoloi/ia vegetale, i. 

■* R. Hartig, Lehrbuch d. Baumkrankkeiten, English edition, 1894, p. 87. 



GIBBERA. 



205 



twigs brown and dead (Fig. 95). If more closely examined, 
the twigs will be found to bear patches of coal-black, 





Fic. Otj. — OiUierii ynrcliiii. Isolated asoia 
with eight si>ores ; jsohited hair from the 
outside of a perithecium. (v. Tubeuf del.) 



Flo. 95. — Giljljtra vaccinii on 
Cowberry. The perithecia forrn 
black patches on the living leafy 
bninch, as well as the dead brown 
one. (V. Tubeuf del.) 



Fill. "JT. — Oihlttra caccinii. CroHa-soction ( ill ow berry »howlnt{ 
a patcli of perithecia in section ; the hairy poritheclii i-untjiin 
jHiraphyses and asci with .•ipores ; jk inyceliuni ]>urnieates the 
eiirtical ti.Hsue of the liost. .Sliort hooked hnii-s i-over the 
upideniiis of the stem. (v. Tubeuf del.) 

Spherical perithecia, which are (niucil by shnii, suuti', uiiiccUuhir, 
black hitirs ( Fii,'. 07). 'I'lic jn'iiiln'cia ((iiitiiiii ]i;ii;iiili\ scs and 



206 ASCOMYCETES. 

asci, the latter with eight or fewer bicellular dark-coloured 
spores. The mycelium is dark-coloured, very vigorous, and 
furnished with many lateral bladder-like outgrowths ; it permeates 
the whole cortical tissue as far in as the wood, and under the 
epidermis forms a brown pseudoparenchymatous stroma, which 
extends over the cortex, and gives rise to numerous perithecia. 
The living cells of the cortex turn brown in presence of the 
fungus-mycelium, and collapse, causing the whole shoot above 
the place of attack to wither and die. 

Cucurbitaria. 

The dark perithecia and pycnidia break through the epidermis 
in large numbers. The asci contain six to eight brown spores, 
divided by cross-septa. 

Cucurbitaria laburni Pers.^ (Britain). The spores of this 
fungus germinate on wounded parts of laburnum {Gytims- 
Laburnum), and, as the branches of attacked plants soon die 
off, considerable damage to nursery stock may result. The 
mycelium spreads through the wood, particularly the vessels, 
in spite of the early stoppage of these by a yellow wood-gum. 
Diseased parts of the wood of living branches appear as dark 
strips ; reproductive organs are produced in the bark, and 
there the plant attempts to isolate the diseased parts by con- 
tinued cork formation. 

If diseased, but still living spots on stems be examined, 
they will be found to include many yellow and black pustule- 
like swellings, some buried in the bark under a periderm eight 
to ten cells in thickness, others in process of breaking through 
or altogether exposed. Many of the pustules will attract 
attention from the presence of red, twisted, elongated tendrils 
on them. On the lower parts of dead branches the same 
appearances will be found, but, in addition, the" periderm will 
generally be ruptured, and the openings so produced filled with 
spherical dark grey or black fructifications. These are variable 
in form, and amongst them can be distinguished some which 
are very large, round, smooth-coated, and light-coloured, with 
a round pore ; others, which appear more warty, and have a 
depressed opening ; while still others, generally smaller, have 

^ V. Tubeuf, ^'■Cucurbitaria laburni." Botan. Centralbkitt, xxvi., 1886. 



CUCURBITAKIA. 



207 



/ 



an acute beaked pore. Where the luirk has been lost, a 
good lens may distinguish the spherical or ovoid dark-coloured 
peritliecia. On the finer twigs the whole 
bark is often perforated ])y numerous tiny 
pycnidia, hardly distinguishable with the 
naked eye. 

If these various forms of fructification be 
submitted to microscopic examination, sections 
through the yellow pustules will show them 
to have that colour, because the transparent 
periderm has become loosened from the rest 
of the bark ; underneath the corky layers 
will be found a red stroma of pseudo- 
parenchymatous hyphal tissue. This stroma 
by its growth causes a gradual rupture and 
loosening of the corky and other layers of the 
periderm : wherever this takes place, conidio- 
phores are developed, and give off numbers of 
tiny, hyaline, ovoid or cylindrical conidia. 
The stroma itself is somewhat spongy, and 
encloses numerous cavities which also become 
lined with conidiophores. At a later period 
the tissue enclosing these cavities may become 
dark coloured, so that structures similar to 
pycnidia are formed. In such cavities the 
red colour disappears, and the hyphae, coni- 
diophores, and conidia a])pear transparent. 
The real pycnidia appear later, and consist of 
a peridium of coarse pseudoparenchyma con- 
taining conidia similar to those just described 
(Fig. 99, A). From the openings of these 
pycnidia the conidia emerge as red tendrils, 
rising as much as one centimetre above the 
pore. Adjoining these forms of sporojthore 
just described will l)e found others : unde- 
veloped pcrithecia with young asci ; dark- 
brown ])ycnidia with brownish-gn-y, nnilti- 
scptate, compi»un<l cunidia ; or similar pycnidia 
with unicellular sphi-rieal, brownish-grey conidia. 

\\'li(!ie the discasf has made furthi-r progress, ilic pustuh'S 




Fio. 9S.—Ciicur0itaria 
laliurni. Plant of Im- 
bunaiin(diiiK'riiiiituatic); 
the liiiiiiclics 1, :;, 4 lire 
still liviiijj, ainl were in 
full foliii^'u (luring the 
l>rccf(Uii>; suiiiiiicr; ii, '., 
c, i/, (, pliiec's wliiTO tlic 
rind i.s <Um(1 iiml tho 
ciirk-layur ni]i"tiirc(l ; iit 
(I iimi li the jHritheeiii 
lire already devehiped, 
and the niyceliiini hiui 
extemled into the wood. 
(After V. Tiibeuf.) 



208 



ASCOMYCETES. 



will be found changing from yellow to black on account of 
the periderm and dead stroma becoming darker. On dead 
branches the large cushions of fructifications will be found to 
include : (a) perithecia with a warty exterior and pores set 
in a depression ; (b) large pycnidia, standing out from the 
cushions, with brown smooth coats, and full of compound 
multiseptate conidia (Fig. 99, b; see below No. 3, a); (c) 
other smaller pycnidia containing the same conidia, but whose 
pore is situated on a sharp prominence (No. 3, h). All or any 
of the three forms may be present. 





Fig. 99. — Cucurbitaria laburni.. A, Stroma with pycnidia containing minute 
unicellular conidia. B, One of the large smooth pycnidia. (After v. Tubeuf.) 



The mature perithecia have a peridium consisting of a loose 
pseudoparenchyma with a rough warty exterior and a pore set 
in a distinct depression (Fig. 100.) The paraphyses are long, 
strong threads, often branched, and between them arise the 
long cylindrical asci with rounded ends. The normal number 
of ascospores is eight in each ascus, but fewer is no exception. 

In addition to the forms already described, pycnidia of still 
another sort occur (No. 1, c). They are spherical, with a 
dark-coloured coarse peridium, and are smaller than the stroma- 
pycnidia. These pycnidia contain no conidiophores, but give off 



CL'CLItBlTAKlA. 



209 



unicellular conidia, at first white, later grey. It is these pycnidia 
which cause the fine perforations of the periderm of twigs. 

Yet another form of pycnidia, previously known as Dipludia 
cytisi (Awd.), (Xo. 4). This, like the last, breaks through the 
corky layers of the bark. It has a peridiuni composed of loose 
pseudoparenchyma and, without the intervention of conidio- 
phores, produces two- celled conidia of a dark greyish-brown 

A 




%: 






KiG. 100. — Ci'Cinhilario labunu. Pcritheciuiii isolated. A, Ejaculiitiiij^ asciir. 
with the inner membrane as yet imruiitured, but emerging Ijeyond the outcr 
ruptured coat. (After v. Tubeuf.) 

colour. This i'orm, however, I iailcd to find in the course of 
my investigation, although I looked through inucli inuterial. 
Tabulating the.'^c various iorius of tVuctificalion wc liu\c : 



.\. PvrNIDIA. 

1. Wliite transparent, sni.ill, miicolliilai- cdiiidia dii Ion-,' conidiu|)li(>irs : 
(rt) Free on tlie .stroma. 
(6) Enclosed in cavities in tlu- stionia : 

(a) In cavities as yet not ii'scinMini: pycnidia. 
{(i) In cavities with (irni daik-colomed pciipluiy. 
{(•) Enclosed in dark-coldiiifil free pycniijia, with ;i peiidiuni of coarse 
pseiidopaivnihynia. 
l'. lirown, unicellidar, i<niiid ccmidia, in little lunwn p\«iiidia (Fig. WD, a). 



210 ASCOMYCETES. 

3. Brown, multiseptate conidia : 

[a) In brown, very large, smooth-coated pycnidia (Fig. 99, b). 
(6) In darker and smaller pvc-niilia with pointed aperture. 

4. Brown, bicelliilar conidia, in little dark pycnidia (Diplodia cr/tisi). 

B. Perithecia. 

5. Brown, multiseptate ascospores, in perithecia generally of dark colovir, 
and with depressed pore (Fig. 100). 

Cucurbitaria sorbi Karsten. This fungus appears to pro- 
duce disease in a manner similar to C. lahunii. It was described 
by me in 1886 ^ from specimens collected in the Bavarian 
forest-land from young Pyrus Anciqmria. They were easily 
distinguished in August by their withered twigs, both bark and 
v/ood being killed in tracts by the mycelium. In another 
locality I found well-developed perithecia, also on P. Auaqmria. 

Cucurbitaria pityophila Fries, occurs on the living branches 
of various conifers, e.g. Pimis Cembra. 

SPHAERELLOIDEAE, 

Stigmatea. 

The naked perithecia are superficially seated on the sub- 
stratum. The ascospores, eight in each ascus, are clear and two- 
celled. The species are parasites. 

Stigmatea robertiani Fr. (Britain and U.S. America). Occurs 
on living leaves of Geranium Rohertianum. 

St. ranunculi Fries. On living leaves of Pmiunculus repens 
(Britain and U.S. America). 

St. mespili Sor. (U.S. America). This species appears in 
spring as reddish-brown spots on the leaves of wild pear-trees. 
At these places the epidermis becomes ruptured, and cushions 
are formed from which brown conidia are given off from short 
conidiophores. This stage was formerly known as Morthiera 
mespili. The conidia are at first obovoid, l)ut later seem to 
consist of four separate cells arranged in a cross, and each 
furnished with a transparent bristle. Each conidium produces 
a germ-tube which penetrates the epidermis, and in a month 

^ 1 have since found from Saecardo that this fungus was described by Karsten 
{Mycol. Fenn., ii. "ad ramosdejectos<s'or/;/nf?(r'(/y;«r/rte in Fennia merid. etmedia"); 
it was, however, unknown for liermany to that author. (Auth.) 



STIGMATKA. 1*11 

new conidial cushions may appear. The mycelium itself is 
brown. From winter to spring, l)rown perithecia containing 
eiglit-spored asci may be found on the same leaves formerly 
occupied by the conidia. The colourless spores consist of two 
unequal cells ; they germinate in May, before or after ejaculation 
from the asci, and l)ring about new infections. 

St. polygonorum Fr. utciiis mi leaves of Fotygonura. (Britain and U.S. 
America). 

St. andromedae Kelmi. On living leaves of Andromeda polifoUa. 

St. alni Fii' k. (Jn 11 vino; leaves of Alnus glutinosa. 

St. juniperi Desm. On living needles of Juniperus fom/iixnis. 

Ascospora. 

The mycelium forms l^rown crusts under the host-epidermis, 
and there the i)erithecia develop. The asci are small and 
contain unicellular liyaline spores. The perithecia contain no 
paraphyses. 

Ascospora Beyerinckii \'uill.^ The conidial form of this 
fundus (I'lirijif II III JJi ij, ri/ir/,ii) produces a form of the "gum- 
flux " of cherry ti-ees. The mycelium lives in leaves of cherry, 
peach, plum, apricot, almond, which in consequence become 
spotted, and die off along with the young fruit. Mature 
perithecia may be found in spring. The fungus lives to a 
certain extent as a saprophyte. 

Sphaerella. 

The delicate perithecia are embedded in the tissues of the 
host-plant ; they contain asci with two-celled colourless .spores, 
but no paraphyses are present. 

Sphaerella laricina llartig.'- The needle-cast fungus of 
hartli. This fungus is the cause of a dangerous larch-disease 
found everywhere, except in mountainous localities over iL'OO 
metres. The symptoms of disease consist in the needles becoming 
brown-spotted and falling prematurely in sunnncr. Cushions of 
conidia arc formed in .lunt; on the brown spots; these enlarge, 
and fioni their surl'ace r(t(l-sha]K'(l, rnur-cellcil cnnidia are 

' Vuilleniin, Ti/iM tl Iravaux srifiitijiijin s, 1890. 

-■ U. Hiirtig, ForM//irh-iintiiririsi. Zulsi-hrift, 18!>5, j). 44."). 
Tliroiij^h the kiiidiieBH of I'rof. Hartig we Iwive beiii i-niil)U'd to iidd an 
iicxount of tills iiiniortant new disease, witii the accoiiipunyiny liguics. (Auth. 
an<l Kdit. ) 



212 



ASCOIMYCETES. 



abjointed (Fig. 103); in the interior of the spots are produced 
tiuy conidia {Lcftostroma laricinnm), incapable of germination. 




Fic. 101. — Tuft of larch needles, the greater number of which are more or less 
attacked by SphaereUa laricina. (After R. Hartig.) 

The rod-shaped conidia infect particularly the lower needles of 
the crown, and three weeks thereafter new conidial cushions 




Fig. 102. — Sphaerella lancina. Section throngli a diseased spot on a larch 
needle. The interior of the leaf is permeated with the intercellular mycelium. 
Two conidial cushions are shown ; from these numerous long rod-shaped conidia 
are given off externally (those of the upper cushion have nearly all been carried 
oflf by rain), while cavities inside the cushions are filled with micro-conidia. 
X ^^. (After R. Hartig.) 



appear. Their distribution and germination are facilitated by 
wet weather. The perithecia (Fig. 104) are matured towards 



SPHAERELLA. 



213 




Spring in the fallen needles, whicli lie on the ground over 

winter. The ascospores are mature and capable of infection 

at the beginning of June. In forests of 

pure larch, or in mixture with spruce, the 

ascospores are easily distributed by wind. 

In larch, underplanted with beech, the spores 

are kept down towards the ground by the 

canopy of beech foliage, so that, during the 

summer, they cannot be carried up to the 

larch crown. 

Hartig gives the following interesting facts 
on its distriljution. 

,, , , , 1 1 ^1 -.1 ■ 1 Fic. 103.— ('., Rod-sb.iped 

As alreadv remarked, the perithecia de- cunidia before and after 

, . . " 1 ,• 11 11 11 dutxthment from the 

velop in spring on tlie lalleii larcli needles, basidia. '., Micro-conidia 

, . , , .' 1 1 • , ■ i 1 1 from the interior of the 

and in li)\v-lying locahties the spores reach cushions, x *■{". (After 
maturity at the beginning of June. Xew '^' "'^'^'sO 
couidial cushions are not found on the larch in our neighliourhood 
before -Tuly. The parasite has thus four months at its disposal 







Fic. 104. —tiplMerclla laricino. Section throut,'h a diseuHed Lireli iioedle in Juno 
after it has liiin on the >fro'""i from the previous year. Tlio niycolium in thick, 
thick-walled, and of a light-brown colour. The peritliccia contuni aHci and asoo- 
8p<jreH. To the extreme right is a pycnidium coutainini,' little oblong conidla, 
alongside a i>eritliccium. y -l-p. (After R. Hartig.) 



for (hslril)Uli()U by means ol' coniilia. .Vs, hii\vc\i'i', we asci-ud 
into the mountains, tlie snow lies lunger, S(» that the peril heeia 
canni»t begin to form so early, the ascospores are correspondingly 
late in reaching maturity, and the season iluring whieli the 
l)arasite may spread is still fun her shoiteiied by the earlier 
<-oiiinieneeiiieiii of winter. .Vl an ele\ation uf j "iiMi metres. 



214 



ASCOMYCETES. 




active vegetation begins about two and a half months later than 
in the plains, i.r. at the beginning of June. The season of 
mature spores of Sx>haerclla is thus delayed till about the 
middle of August. On 2Gth September I found at this elevation 
only a few spots on the larch needles, and 
on these hardly any conidial cushions. By 
28th September this larch plantation was 
already under snow." 

" It will thus be seen, that while at a 
high elevation the larch can flourish with 
a vegetative period extending only to three 
and a quarter or four months, the Sphaerella 
has not the time necessary for its develop- 
ment, so that the larch, though much 
handicapped, remains healthy. Similarly 
with the larch in Siberia, it grows there, 
as in the mountains, very slowly, yet this 
parasite can no longer reach it." 

Sphaerella fragariae Tul. Strawberry 
leaf - blight.^ In summer free conidia 
{Ramularia Tulasnei Sacc.) and pycnidia 
are produced, while the perithecia ripen in spring. 

[This destructive disease of the strawberry has been recorded 
from all parts of the United States. It first appears on the 
upper surface as small reddish spots, which rapidly enlarge, 
the centres withering and browning. The growth of the plants 
and the crop-yield is seriously impaired.] (Edit.) 

Sph. gossypina Atks.^ [Cotton leaf-blight is a disease on 
leaves of the cotton plant caused by the Ccrcospora-^iQ.ge of this 
fungus. Small reddish spots appear on the leaf, enlarge, and 
become dry whitish spots with a red margin. The conidia 
are elongated and produced in long chains. The asci contain 
eight elliptical spores, which are slightly constricted at the 
septum when mature, one cell being usually somewhat smaller 
than the other. This disease frequently accompanies that one 
known as " yellow leaf-blight," or mosaic disease.] (Edit.) 



Fig. 105. — Enlarged asci. 
o, Immature asci without 
paraphyses, as on April 30. 
b, Mature asci, from one of 
which the spores are escap- 
ing, as on June 1. x ^\^. 
(After R. Hartig.) 



^ Trelease, Wiuconsin Exper. St a/ion, 1885. 
Scribner, F. L., Beporf U.S. Depl. of Afj7-icultnre, 1887. Plate, 
papers by Arthur, Dudley, and Garman. 

^Atkinson, Bulletin Torrey Botan. Club, Vol. xviii., 1891. 



Other 



srJIAERELLA 



215 



Sph. mod Fuck, causes a similar disease on leaves of mulhi'irv (U.S. 
America). 

Sph. taxi Ckc. On the yew.i 

Sph. longissitna Fuck. On living leaves of Bronuis asper. 

Sph. depazeaeformis (Auersw). On living leaves of Ontlis acetosella and 
O.r. .■nrniralatn. 

Sph. brassicicola (I)iilt\-.). On withering leaves of Brassicae. (Britain 
and U.S. America. 

Sph. laureolae (Desm.). On living leaves of Daijlme laureoki. 







Flu. 106.—Si>>i'iertlln fragariae on loaf of Stiiivvlieny. Tliu soctioii throutfli a 
siMjt show.s formation uf cuiiidiii. (v. Tiil>cuf dul.) 

Sph. hedericola (Desm.). On living leaves «.f jvv. (Hiitain). 

.Allisclirr -' (lesciilies other fungi on ivv. 

Sph, Gibelliana (Pas>.). (hi li\ing leaves nf U/V/vw liinoninii and C. 
Vi(:di< ■!. 

Sph. poiypodii ( Ualih.). On living fmnds ..f I'tili/podiitm nilijitre, Asjii'/inin 
r ili.i iiiiis, As/idiii iiin TrirliO)ii<iii('.-<, I'Iitik (HjitHina. 

Sph. vitis Fuck. On withering vine-leaves. 



' Woitli. (i. Smith. (ImiliiKi-'s Chniuirl, , x\i., I8S4. 

5 AUertelier, " I'.liitttlLckeiiki aiikli.it .1. \\\\\\\u-n," Z. its,!,, j. /'ff.-krnnkhtitfU.lSiKK 



216 ASCOMYCETES. 

Sph. sentina (Fr.) (U.S. Araei-ica). In spring of 1891 this caused at 
Geiseuheini ' a severe spot-disease on the leaves of certain varieties of pear. 

Other related species occur on pear. 

There are numerous other species of Spliaerella. Saccardo gives 279 
species, many of which are probably more or less prejudicial to plants in 
orchard or garden. None, however, are recorded as very injurious. 

Laestadia.^ 

This genus is similar to Sphacrdla, but has one-celled 
conidia ; it is distinguished from Physalo»pora hy the absence 
of paraphyses. 

L. maculiformis (15on.) on living leaves of various trees. 

L. (Physalospora) Bidwellii (Ellis) ^ (Britain and U.S. 
America). The Black-rot of the Vine. This parasite attacks 
all young organs and shoots of the vine. On the leaves the 
symptoms are spots with dark sharply-defined margins, on which 
the pycnidia appear later as minute black pustules. The leaves 
die, but do not fall off, as with Spliaceloma ampelinum. The 
berries show disease when only the size of peas, and finally fall 
off singly or in clusters. The grapes are not dusty with a 
mealy powder, nor do they burst as in attacks of Oidivni 
Tuckeri. Two kinds of pycnidia occur: one sometimes described 
as spermogonia, has very small rod-like conidia, borne on thread- 
like conidiophores ; these conidia have not as yet been seen to 
germinate. The other pycnidial form {Phoma vvicola of Berk, 
and Curt.) contains forked filamentous conidiophores, from 
which one-celled ovoid conidia (stylospores) are produced and 
soon germinate by emission of a septate hypha. The latter 
form of conidia is produced after the spermogonia, and may be 

^ Geisenheim Jahrbuch, 1892. 

^According to the laws of priority this genus must, as shown by Magnus 
{Oesttrreich. holan. Zeit., 1894, p. 201), be called Carlia. Bon. 

^ Bibliography : Cavara, Intorno al dissecamento dei grappoli della t-ile, 1888. 

Thiimen, " Die Black-rot Krankheit d. Weintrauben." Alleg. Weinzeitunq, 
Vienna, 1891. 

Galloway and Scribner, Reports for 1888-89, U.S. Dept. of Agriculture. 

Viala and Eavaz, Lea Froip-es agric. et viticoh. Montpelier, 1888-89. 

Rathay (1), Dtr Blavh-rot, 1891. With 19 figures (2). Bmcht iib. eine nach 
Frankreich z. Erforschunfj d. Blark-rot Krankheit Reise, 1891. With 7 figures (3). 
Der White-rot in die Weinlaube, 1892. 

Viala. Die Krankheiten d. Weins/ockes. 

Linhart u. Mezey, Die Krankheiten d. Weiustorkes, 1895 (Hungarian). 

U.S. Dept. of Agriculture. Numerous references in reports and bulletins, 
where details of treatment experiments Mill be found. 



LAKSTADIA. 217 

found riuht on into autumn, even throughout the winter. 
Jlibernating .sclerotia are also produced, the cells of which grow- 
out directly into septate conidiophores with oval cimidia. 
Perithecia, externally resendding pycnidia, are formed in ^lay 
and June on the fallen herries of the preceding year. The 
a.sci have gelatinous walls, which swell and burst so as to 
ejaculate their spores. Viala and Puivaz successfully infected 
living grapes by means of the larger conidia, and also by 
the germinating ascospores. 

The disease is one of the most dreaded in America. It has 
been found also in Europe, having l)een observed in France 
since 1885, though nut as yet in Germany, Switzerland, Italy, 
or Spain. Moist situations are favourable to it. As with 
other diseases of the vine, the various varieties have ditierent 
powers of resistance, and a judicious selection of varieties may 
prove a good preventive measure. According to Viala, the 
black-rot is found in the United States on both wild and 
cultivated vines, but never on the fruit of Vitis rupesfris, V. 
Birlancicri, V. cincrca, V. Lii'secomii, V. J/o/ificoIa, and V. 
niiidicHiis, and very rarely on their leaves. The "vine-stocks" 
themselves suffer little or nothing from the disease. Ifathay 
says that Vitis riparia, V. n'pcstris, and V. Sohni.H, .so im- 
portant as grafting-stocks, are seldom affected ; the green 
•shoots of other species, however, may be attacked and the 
disease Ite transmitted through the graft-slip. 

For combating the disease, (ialloway, Prillieux, and rKclu.se 
recommend liordeaux mixture.^ 

Laestadia buxi (Desm.). The perithecia of this species are 
found a.> liny jjoints on yellow .spots on the lower surface of 
green leaves of box. This fungus, regarded by Desmazieres as 
saprophytic, is said by Priosi and ( 'avara to be para.-^itic. 

PLEOSPOREAE. 

Physalospora. 

The ]ierithecia arc Inmicd under the epidermis, l»ut are 
otherwise devoid of covering ; they contain a.sci and )»araiihysi's ; 
the spoics arc oni'-cellcd. ;iiid ((\iii.l i<v i-Ilipi ii al. 

'For ilftiiilH ste Itjitliay (/<><•. ciV. ), tlir .Ann ri.aii luillftins, etc. 



218 ASCOMYCETES. 

Physalospora laburni (Boiiord.) occurs ou living twigs of Cr/tisus Laburnum. 
Ph. fallaciosa .Sacc. On withering leaves of Aletris and Mii^a in Berlin 
Botanic Garden. 

Didymosphaeria. 

Perithecia similar to Physalospora, Ijut with two-celled spores. 

Didymosphaeria genistae Fuck, occurs on Genista pilosa. 

D. epidermidis (Fries). On living branches of Berheris, Sambucus, Salix, 
and Eucalyptus. (Britain and U.S. America). 

D. albescens Niessl. On living branches of Lonicera Xylosteum and 
Myricaria germanica. 

D. dryadis (Spegazz.). On living leaves of Dryas octopetala. (U.S. 
America). 

D. populina Vuill. Prillieux and Vuillemin ' regai'd this as a parasite, 
and the cause of a peculiar dying-off of Populus pyramidalis throughout 
Germany ; Rostrup, on the other hand, ascribes this to Dothiora sphacriodes 
Fr. Prillieux I'egards Xapicladium tremulae as a conidial form of Didymo- 
sphaeria ; Vuillemin, however, believes it to be saprophytic. 

Venturia. 

The perithecia are embedded in the stroma, and have stiff* 
bristles round the pore ; they contain both paraphyses and 
eight-spored asci. The spores are two-celled, with or without 
colour. 

Venturia geranii Fr. occurs on the living leaves of Geranium pusillum, 
G. molle, etc. 

V. rumicis (Desm.). On withering leaves of llume.i-. (Britain). 

V. maculaeformis (I)esm.). On living leaves of Epilobium. 

V. vermiculariaeformis Fuck. On withereil leaves of Euonymus europaeus 
and Lonicera Xylosteum. 

V. Straussii Sacc. et Roum. This I have found as a parasite on Erica 
carnea in Tyrol. It is also said to cause a disease on Ericaceae in France. 

The various conidial forms at present placed amongst the 
" Pungi imperfecti " as Fvsickidiuiii are proljaljly related to 
Vcnhirid. 

Fusicladium dendriticum AVallr. on apple, and F. pirinum 
Lib. on pear, are at present the subject of an investigation at 
the hands of Aderhold,^ who has, on account of their perithecia, 

^Bullet, de la soc mycol. de France, 1892; Comjit. nixL, 1SS9 ; Ririw nu/col., 
1892. 

^Aderhold, "Die Perithecienform v. Fus. dendriticum'' Vovhin^g Mittheilung, 
Ber. d. deutsch. hot an. Ges., 1894, p. 338. 



VENTLIUA. 



219 



placed them in the genus Ventv.ria. His investigations are, 
however, not quite complete. 

The seal) or black spot of apple and pear is a very familiar 
disease in America and elsewhere. It attacks leaves, young 
shoots, and fruits. Dirty greenish spots appear first, then enlarg- 
ing, they run together, and darken in colour till almost black. If 
the attack occur on young foliage, it may be dwarfed and killed ; 
the newly-formed fruit will in such cases be attacked, shrivel 
up, and fall. If the attack be deferred till the foliage and fruit 
are well advanced, then spotting results and the fruit remains 
hard, perhaps cracks. The cunidia are oval, unicellular, and 
yellowish-brown ; they are produced from short conidiophores 




Fl(i. lOT. — I>>i<(0-K( {Fi'xicloilixi.m) c/uuZ/idt.',.. fi.iiiiiii^' I.iovmi .-iMits on ati 
iipjjle ; those still in the earlier stajfes have a radiate niar^nii and bear conidia. 
The enlarged seetion shows two rows of lai-ge-eelled imrenehyina of the apple, 
covered by a stroma of pseudoixirenelivnia hearing conidiophores and conidia. 
(V. Tuljcuf del.) 



witli waily pioiiiiiieiices wliieh grow on sjtots of leaf or I'niit 
(Fiu. 107). The perithecia (as yet tlescribed) are di.'^tiiiL:iiished 
Ijy black bristles surrounding tlie pole, ami occur on fallen 
leaves. The asci contain eij^lit greenish ovoid spores witii two 
or ibiee eeli.s. 

ill addition to the injury to leaM'.s and desirueiioii of young 
I'niil, the di.stiguration of the apples is a cause of considerable 
moiK'taiy lo>>. l»ibitf I'.mtlraux oi copjicr siilphale iiii.MiUf 
applied beloir the ojpi-niii;.^ of l>iids, and oiuc or twice al'tt-r 



220 ASCOMYCETES. 

" setting " of the fruit, is recommended. Xo fungicide should, 
however, be applied towards the ripening season.^ 

Gibellina. 

The splierical perithecia are embedded in the stroma, theii' 
necks projecting. The asci contain eight brownish spores, 
oblong or spindle-shaped, and bicellular. 

Gibellina cerealis Pass. This parasite of wheat has hitherto 
been fairly cuunnon in Italy ; recently it has appeared with 
disastrous effect in Hungary. According to Cavara, it produces 
on the under part of the stems, grey plate-like coatings with a 
brown margin ; these may remain as spots, or enlarge till they 
form a ring round the stem. The perithecia are little black 
points arranged in rows, and embedded under the epidermis, 
except the black projecting necks. The asci have thin walls and 
break up inside the perithecia ; they contain eight spores arranged 
in two rows. The spores are spindle-shaped and bicellular, but 
their germination has not as yet been observed. The mycelium 
is found in all the host-tissues, besides forming a stroma-like 
sheath round the stem. The plants attacked become brown and 
limp in early summer, and no fruit is produced."^ 

Cavara recommends early removal and burning of affected 
stems, and the cultivation of crops other than cereals on the 
infected ground. 

Leptosphaeria. 

Perithecia black, rarely with bristles ; at first they are em- 
bedded in the host, without a stroma. The spores occur four to 
eight in each ascus ; they are spindle-shaped and generally 
multicellular by means of cross- walls only. Thread-like para- 
physes are always present. 

Leptosphaeria herpotrichoides de Xot. This species, gene- 
rally regarded as a saprophyte, was found by Frank ^ as a 
parasite on rye. The stalks attacked break over at a node or 

' Further details of treatinent-experinients are given in Gall and Scribner's 
" Report on Experiments for 1889," C^.S. Amer. Dept. of Agricitffiire BuUetin ii. ; 
also in the IJnlletins of various Experimental Stations. The above account has 
l)een considerably extended by aid from the American literature. (Edit.) 

-Cavara (Zeitschrift f. Pflair-enh-anl'Iitittn, iii., 1893, p. l(j) gives a detailed 
account of this fungus with illustrations. 

■'■Frank, ZtituchriJ't f. PJlanzenh-ankheAten, 1895. 



LEPTOSPHAKRIA. 221 

just over the root, thus reseniblinu- the ^^yluptolu.s accouipanyin^ 
an attack of Hessian Fly. 

L. tritici Pass, is said by Frank t<> be de.-<tructive to wlifut in (Teiuianx . 
(See also i'ladosporium). 

L. subtecta Wint.^ In Tviul the peiithecia of this species acconipauy 
disease of the leaves of Erica carin'a. Simultaneously Hypodenna en'cae 
Tub. and Sphaeria encina Tub. were found, the former appearing to cause 
the disease (see p. 234). 

L. anceps Sacc. On living Viranehes of Riles nignim. 

L. vitigena (Schulzer). On living tendrils of the vine. 

L. circinans Sacc. (see Rhizoctonia p. 201). 

L stictoides Sacc. vw Liriodendron tulipifera is an Anu-riean species. 

Pleospora. 

The black perithecia are not developed on a stroma, ami 
are at first concealed in the host-tissues only. They contain 
parapliyses and eight-spored asci. The spores are multiseptate, 
and oenerally colonied. 

Pleospora hyacinthi Sur.-' i)roduces black coatings on the 
bulb-scales of hyacinth. The mycelium inside the tissues is 
colourless, but outside is dark red, and its presence causes disease 
of healthy parts. Certain perithecia which appear on the liull»- 
scales in autumn may perhaps belong to this fungus. 

P. tropaeoli Hals, is given as a disease of Tropaeolum in l'..S. 
America.'' 

P. hesperidearum Catt. The conidial form {Spornhshuum 
h'-^ji.) a]i|>ear.s as a black coating on the orange. 

P. ulmi Fr. {rar. jninor) Allescher, causes a leaf-spot on young 
elm-seedlings, and the leaves drop off prematurely. 

P. napi Fuck, is the cause of rape-snnit. Leaf-s[)ots carrying 
conidial cushions {SporiihamiKm v.dtivsinn Kiihn) appear im the 
rai)e and rither allied root-crops. 

Ofhii '• blark smut-diseases" have been asriib.-d t^ Polydesmus (Spori 
desmium) exitiosum {v<ii' Davri) on carrot ; Helminthosporium gramineum 
Ral)li. causing withering of lyc and barley K-aves; an>l Sporidesmium 
putrefaciens Fuck, whith attacks imd kills tin- young )icart-Ifa\ es of l>oil- 

I-oot. 

'v, Tubeuf, Bolan. CeutruIUnft, .\xi., iss.";. 

-Sorauer, Jlainflnirh it. J'fltur.fiikraidli' if' ii, ii. Anil., p. .'UO ; ami i'li'i rsiirh. 
iih. tlii lliii<iilkraiikht it u. <l. Ituxxthnu </. II iitirinlhi n. Leipzig, 1S7S. 
■^N. Jnsiy A'jrlr. Kjj»,: S/'i/. I!> i>i>rf, l.S, IS<t-_'. 



222 ASCOMYCETES. 

Dilophia. 

The genus is parasitic and causes swellings. The perithecia 
remain permanently embedded in the tissues of the host-plant. 
The asci contain eight transparent, thread-like, finely-pointed, 
nudticellular spores. 

Dilophia graminis Sacc. (Britain). This causes deformity of 
the leaves and intlorescences of wild grasses ; also of rye in 
France, and wheat in England and Switzerland. Fuckel assumes 
a relationship between this species and Bilo'plios'pora graminis 
Desm., but this we regard as doubtful. 

Ophiobolus. 

Perithecia scattered and almost spherical ; they contain para- 
physes and eight-spored asci. The spores are hyaline or 
yellowish, thread-like, and unicellular or septate. The fungus 
is minute and inhabits stems and haulms. 

Ophiobolus graminis Sacc. was indicated by Prillieux, 
Delacroix, and Schribaux as the cause of a cereal disease in 
France. The cereals attacked broke over very easily near the 
ground ; they continued to develop, but produced ears of a poor 
quality, and often quite withered. The disease was designated 
" maladie du pied des cereales," and described in Jour. cVAgric. 
fractiqiLc, 1892; also under the name "la maladie du pied du 
ble " in Travaux du lahor. cle patJiol. vegetalc inst. agronom., 
1890. The perithecia have a curved lateral beak; the asci 
contain eight long, spindle-shaped, multiseptate spores. 

Frank also records this disease as injurious to wheat in 
Germany in 1894. 

GNOMONIEAE. 

Gnomonia. 

Perithecia without a stroma, and generally remaining 
embedded in the host-tissues, with only a beaked opening pro- 
jecting ; they contain no paraphyses. The asci have a thickened 
apex with a fine central pore. The hyaline spores consist of 
from one tn four cells. 

Gnomonia erythrostoma Auersw.^ This is the cause of an 

^ Frank, Ber. d. dentsch. hotan. Ges., 1886 and 1887 ; also Zeitschrift f. 
PJlanT.enkrankheitat, 1891. 



GNOMnNIA. 223 

epidemic disease of the cheny (Prunus aciam and F. Crnisus), 
observed for several years past in Xorth Oermany and else- 
where. The fungus attacks the leaves, and there the niyccliuni 
grows. The leaves witlier prematurely, but rtnaain all winter 
hanging from the tree by a reddish-brown mycelium. Tycnidia 
and perithecia are produced in the leaves, the latter reaclnng 
maturity in spring, when tlie two-celled ascospores are ejaculated. 
The pycnidia contain short conidiophores bearing hook-shaped 
conidia. The fruit is also attacked, and ripens unequally, so 
that the cherries are distorted : then they crack and rot. 

Frank has succeeded in carrying out artificial infection. This 
takes place in June, and immediately on germination tlie gerni- 
hypha produces an attachment-disc on the host-epidermis, whence 
a hyphal filament penetrates the epidermal wall, grows through 
the cell, and reaches an intercellular space. A thick septate 
mycelium is formed and spreads, especially amongst the spongy 
parenchyma. There is no stroma, and the peritliecia hibernate 
on dry leaves. 

Frank recommends the plucking and burning of dead leaves 
hanging on the trees. This must of course be done througliout 
the whole district attacked. In one part of Prussia (Altenlande) 
this precaution was taken twice each winter for two years, 
with the result that the disease, which had long completely 
ruined the cherry crop, disappeared, and the harvest increased 
to its former amount. 

Gnomonia quercus-ilicis 15erl.' causes br<>wn spots on leaves 

of l^hh icii.-i IUj:. 

VALSEAE. 

Mamiania. 

I'eritliecia produced in a black stroma, from which their long 
necks ])roject. The asci have a thickened ai)ex, and contain 
eight o\al hyaline spores wiili one or two eells. 

Mamiania (Gnomoniella) fimbriata I'ers, (liritain and T.S. 
America). The -iroiiiaia dt this a]i]M-ar in summer as little 
black cushions on the leaves of the bornbeani (Cn riiinns). Tlu- 
perithecia are developetl in these spots, and their long black 
beaks projectinu (listindly above tlie surface of the leaf cause 

' ISi'llfsc, liiristd ili I'atoioijid. rn/tftt/t , I. 



224 



ASCOMYCETES. 



rupture of the epidermis. Xuinerous leaves may be diseased 
and each carry many cushions, yet Yuillemin, who described 
the disease,^ does not believe the host-plant is affected to any 
serious degree. 

M. (Gnom. ) coryli Batsch. (Britain and U.S. America). The 
black struniata are found in withered spots on the leaves of 
hazel {Corylus) ; as a rule, each stroma carries oidy one peri- 
thecium witli a lon^- beak similar to that of M. fimhriaf". 




Fio. 108. — Mamiana fimhriata on Carpinus Bclulas. Leaf of Hornbeam seen 
on lower surface. Stroma (enlarged), with the long black necks of the perithecia 
projecting from the ruptured leaf -epidermis, (v. Tubeuf del.) 



Valsa. 

A stroma is generally present, but is of very variable appear- 
ance ; embedded in it are the perithecia, with only their beak- 
like mouths projecting. The spores are hyaline or light-brown, 
unicellular, and generally bent. Xo paraphyses are present. 

Valsa oxystoma Pichm.- This causes disease and death of 
branches of A/iws 'cirulis in the Alps. The symptoms are 
withering and drying up of single branches on an otherwise 
green bush. This disease causes severe loss in the Tvrol, 



^ Titres et (ravanx scientifiqnes, 1890. 

-V. Tubeuf. "Zwei Feinde d. Alpenerle," For-stlicli-iia/unciss. Ztilschrijt, 1S92. 



VALSA. 



225 



where leaves of the alder are dried in sumnier for use as 
winter-fodder for goats. 

In the branches attacked, a mycelium is developed in the 
vessels of the wood, whereby the supply of water is stopped 
and the bark dries up. Black lens-shaped stromata arise 
under the epidermis of the twig and rui)ture it. The peritliecia 
are produced under the stromata in the bark, and communicate 




o o^*^ 



ly 



Fio. Ujy. — Valm oj-i/itomu on Atnus tiiulis. A, I'ortion ol liniiu-li witli stroiiui 
of Vatsa breaking tbinrngh the periderm at four places. W, Knbirgod section 
through :i stroma from A. C, And and aHcospores, isoLited from a i>eritliucium. 
D, I'ortion of younger liranch witli periderm ruptured Jiy stromata, in wliicli, 
however, the jieritlieeia are not yet developed. £, Enlarged section through a 
stroma of J). (After v. Tulieuf.) 



with the exterior liy means of long projecting necks. Tht- 
asci contain eigiit unicellular spores of u slightly bent, md 
like shajtc. Maturity is reached (ni (he ihy dead twigs. 
E.xternally this disea.se is itlentiial in ajjpeaiiince with uiu' 
I a.scertaiiicd to Ik* due to ;i Iji-dle {('ri/ptdrltijiichns Uijiathi). 



226 ASCOMYCETES. 

the larva of which bores canals m the wood of alders, birches, 
and willows, causing them to die. 

Most of the other species of Valsa cause only leaf-spot, or 
occur on dead leaves. 

Anthostoma. 

The perithecia are embedded in the substratum or stroma, 
and have generally long necks. The asci contain eight brown 
or black, oval, unicellular spores. Paraphyses are always absent, 

Anthostoma xylostei (Pers.) occurs on living and dead 
branches of Lonicera Xylosteam. (Britain). 

Anthostomella pisana Pass, lives on leaves of Chamerops humilis and 
kills them. 

DIATRYPEAE. 

Calosphaeria. 

No stroma is formed, the perithecia arising singly or in 
groups in the bark under the periderm ; th ey have often long 
beaks. The asci are club-shaped, and frequently long-stalked ; 
they contain eight or more spores, which are little, unicellular, 
and somewhat curved. 

Calosphaeria princeps Tul, occurs on living branches of 
cherry and plum. (Britain and U.S. America). 

Quaternaria Personii Tul. has black perithecia and, according to Will- 
komm, causes death of twigs of beech. (Britain and America). 



MELANCONIDEAE. 

Aglaospora. 

The perithecia are beaked and embedded in the stroma. The 
spores are furnished with appendages. 

Aglaospora taleola Tul.^ {Dicqiorthc talcola Fries, and pro- 
bably nearly related to those Melanconi with appendages on 
their spores, e.g. Mel. tlielebola, previously known as Aglaospora 
thel. Tul.). (Britain and U.S. America). This fungus causes 
a disease of twigs and young stems of oak which have not 

1 R. Hartig, " Eine krebsartige Rindenkrankheit d. Kiche," Fo7-silirh-naturwit<s 
Zeitschri/t, 1893. 



AGLAOSPORA. 



227 







■^" 



■•^.' 




^§j3iltf*e— 



Fiii. 110. — KxiiiiipluM i)f (Jak-Htciii iittiiikoil liy .<>ilaospoi-a talcnlo. 1, I'ortioii 
(llHoiutod for tw» yearn; a, tho purtluii Htlll liL-iiItliy ( >^ f )• -• i'urtinii (HhviihoI 
for four ycarx ( x ^). 3, Section with Hi)ot» iliHoiiMud for four, lovoii, und ten 
yoiim roHiKictlvoty (x } ). (After it. Hiirtit;.) 



228 



ASCOMYCETES. 



as yet formed a bark. Portions of the rind become brown, 
dry up, and peel off ; this on stronger twigs may be followed 
by a more or less complete occlusion of the wounded part. 
The browning also extends into the underlying wood. The 
mycelium is found both in rind and wood, where it probably 
obtains entrance through small wounds in the bark. In the 
second year after infection, a circular stroma is formed in 
the bark under the periderm. Sickle-shaped conidia are 




Fig. 111.— Aglaospora ialeola. Portion of cortex with embedded stromata. 
fi, Corky layer; h, after removal of corky layer; c, section of stroma. { x ^.) 
(After Hartig.) 



:mr"='-"''-5^^ 



^ 
■^ 

r. 




Fig. 112.— Section of stroma oi Aglaospora. a, Boundary 
of stroma formed of dark brown fungus - mycelium ; 
6, sclerenchyma-strand of the cortex ; c, conidial cushion ; 
d, union of necks of two perithecia. (After Hartig.) 




Fig. 113. — a, Conidia ; h, asco- 
spore of Aglaospora toJ.eolo. 
( X -^f^). (After Hartig.) 



superficially abjointed from the stromata ; while embedded 
in it are groups of perithecia with necks which join together 
into one or a few common channels opening externally. The 
asci contain eight spores, which are two-celled and bear five 
thread-like appendages, one on each end, and three round the 
median septum (Fig. 113). 



AGLAOSPOKA. 229 

Ag. profusa Fr. (Britain and U.S. America). Tliis occurs 
alon<^ with, and probably is some form of Dothionila rohinute. 
Prillieux and Delacroi.x ^ blame it for killing younu; twigs ftf 
Iiobinia pscudacacia in France. 

Fenestella. 

The stroma is similar to Ea- I'alsa, and contains several 
long-necked perithecia. The spores, eight' in each ascus, are 
coloured and multiseptate, as in Cxcurbitaria. 

Fenestella platani Tav., to this is probably related Gloeo- 
sporii'iii ii> rrisripimiii (Fuck.), the cause of a disease on the 
leaves of Platanus, and described under Gloeosporium. 



(3) DOTHIDEACEAE. 

Phyllachora. 

The peritliecia are small and produced in a Itlack stroma 
biirieil in the tissue. The asci contain eight hyaline, oval, 
and uiiici'Ihilar spm-c^. 

Phyllachora graminis (l*«'i'^.). (U.S. America). This species 
causes elongated Ijlack swellings on grasses and sedges (Li'tnl" 
and Care.e). The black perithecia occur massed together, and 
embedded in the leaves. The asci contain eight hyaline uni- 
cellular spores. 

Ph. trifolii (Pers.), with conidial f(jrm known as PoJi/thrinr'nim 
trlj'iAiL Kunz. (liritaiu and U.S. America). The mycelium 
causes the formation of roundish dark spots on the green 
leaves of clover frequented by it, and death ultimately follows. 
On the spots, especially those on the lower epidermis of the 
leaf, the conidiophores make their apjjearance as brown septate 
structures, constricted at intervals so as to become rosary-like; 
they bear terminal, brown, two-celled ronidia, tlie upper cell 
of which is somewhat spherical, aud larger than the lower. 

Ph. cynodontis (Sacc). On livinjf leaves of Cynodoti Dtirtt/lon. 
Ph. podagrariae (If>>tli.). ()ii liviiiLj leaves nf Aiyofioi/hiin I'oditijntrux 
(Britain). 

Some ntliiT >](c<ic.s are fouinl on wil hci iiiLj leaves. 

' lUtlhliit ■<or. „ii/'o/. ,/. Fnnir,, IS'.IO. 



230 ASCOMYCETES. 

Diachora onobrychidis (D. C.).^ This fungus is common 
on sainfoin {Oiuihrijcliis sativa) and Lathyrus tuberosus, causing 
black spots on both surfaces of the leaf. During summer 
pycnidia arise on the spots, and from them are produced spindle- 
shaped conidia (spermatia) with tail-like appendages. Later 
there arise spherical perithecia containing asci arranged in tufts 
on the walls. The asci contain eight oval, hyaline, unicellular 
spores. 

Dothidella. 

The perithecia are black and embedded in the stroma, 
similarly to Phyllacliora. The pale- coloured spores are, how- 
ever, two-celled. 

Dothidella betulina (Fries.). (Britain and U.S. America.) 
The black stromata form spots on the upper surface of 
birch leaves. In these the perithecia arise, and reach maturity 
in spring. The asci contain eight elliptical greenish spores, 
consisting of two unequal cells with rounded-off ends. 

D. ulmi (Duv.). (Britain and U.S. America.) A species 
similar to the preceding, and causing round blistered spots 
of a grey colour on the upper surface of elm leaves. Pycnidia 
{Piggotia astroided) are formed in summer, perithecia in the 
following spring. 

Dothidea. 

The stromata have the form of black projecting cushions, 
in which numerous perithecia are embedded. The asci contain 
eight greyish or brown spores, consisting of two cells with a 
constriction between them. 

Dothidea virgultorum (Fries.) attacks living branches and 
stems of birch, and develops further on the dead parts. The 
stromata originate in the wood, then breaking through the 
bark, make tlieir appearance externally as large black cushions. 
Whole stems may be covered by these cushions. 

D. sphaeroidea (Cke.) occurs on living needles of juniper. 

Plowrightia. 

The stromata are black, and run together in masses. The 
asci are eight-spored ; the ascospores ovoid or oblong, hyaline 
or light yellow, and two-celled. 

^J. Miiller, PriiKjsheiyn's Jahrhurk, 1893. 



PLOWRIGHTIA. 



231 



Plowrightia morbosa (Sch.) (lUitain and U.S. America). 
Black-knot of the plum tree.* In America this is a very 





Flo. 115. — Ploicrightia mor- 
bosa. Ascus, with eight 
spores. Spores in gcrtnina- 
tion. Filamentous jNira- 
physes. (Cop. fruin Farlow.) 



I'll.. \\i.~PloirngUli<i „ioibom. (v. Tiibciif jiliut.) 



injurious and widely distributed disease of various species of 
rrunas, especially plum and cherry. Tlie living branches ami 
twigs become coated with a crust of warty excrescences, and 
at the same time are more or less thickened and dcrniiui'd. 
A mycelium permeates the tissues of tliose swollen Iwii^s, and 
forms black crusty stromata in which the perithecia are 
embedded. The perithecia contain sim})le para])hyses ami eight- 
spored asci. The spores consist of a larger and a much smalh-r 
(I'll. ( l'ycno-C(jnidia arc produced frecpicntly in arliticial culture, 

'Kiiiliiw. HiUhtin liiisiiij Iii.i/i/utl<iii, I'ait v., 1S7(). 
HuiMpliny, Annual Iti /tort of M(i-s.i. Kjjh r. Stddun, 1890. 
LodfiiiiUi (('oi-nfll I'uir. Expff. Stu/ion, Itulhtin No. Kl, iS'.t-l) givi-ti 
geiUTiil iu-coiiiit nf ni.Kk-kiKit iiiiil ii 15ilili<>j.'ra|)liy. 



232 ASCOMYCETES. 

but are rarely found in natural conditions ; as yet infection 
with these has had no result.) 

[Remedial treatment must be promptly applied. Trees liable 
to attack should be frequently examined, so that any young- 
knots may be early removed. If the disease is of long standing, 
the only remedy left is to remove all knotted branches and 
burn them immediately.] (Edit.) 



HYSTEEIACEAE. 

The ascocarps of the Hysteriaceae, like those of the Discomy- 
cetes, are known as apothecia. They are distinguished from 
those of the Pyrenomycetes and Perisporiaceae in that 
the ascocarp, although formed in or under the epidermis of 
attacked plant-organs, is not a closed structure or tiask opening 
by a pore only ; it is, indeed, at first completely closed, but 
later it, as well as the epidermis covering it, splits open and 
freely exposes the whole hymenium. So long as the apothecium 
is closed, it is filled with paraphyses, between which the 
developing asci gradually wedge themselves. The spores 
are generally thread-like, with a gelatinous meml^rane. The 
mycelium lives intercellular, and is often parasitic in living 
plants. The apothecia, however, only reach maturity on parts 
which have been killed. In addition to apothecia, little pycnidia 
(spermogonia) are formed, containing small unicellular conidia. 
The Hysteriaceae include the Hysterineae, Hypodcrmkac, Dickae- 
naceae, and Acrospermaceae. 



HYSTERINEAE. 

Hy sterogT aphium . 

Apothecia black, highly vaulted, and dehiscing by a linear 
fissure. The asci are club-shaped and thick-walled ; they con- 
tain eight multicellular spores, which are at first transparent, 
but later dark-coloured. The branched paraphyses of the 
ujjper part form a coloured epithecium.^ 

Hysterographium fraxini (Pers.) (Britain). This occurs on 
various Oleaceae and some other species of woody plants. 

^ The exciiniluiii of ])e I>ary. 



HYSTEROGRAPHIUM. 



233 



Eostrup ^ regards it as a parasite on Fra.cinus. Twigs of the 
ash attacked show Hat collapsed plates of bark, on which are 
developed pycnidia containing one-celled conidia, and, later, 
the apothecia. On young twigs the diseased part often extends 
round the whole circumference, and causes the death of the 
upper living part. As yet I have only found tliis fungus as 
a saprophyte. 

HYPODERMIEAE. 

Hypoderma. 

The apothecia are oblong, and at tirst closed by a thin black 
cover, which opens by a long fissure. The asci are sessile in 






Fio. ll'i. — Hiti>'nlir,i\o. ft i-olj'icoUi. ou Piitim 
Stiobu*. Ascus cuntaining eight ascospores 
with gelatinous coats ; paraphyses with 
clavate ends. (After v. Tubcuf.) 



Fig. 117.— //,w/.<.</.,-.„(( >i,-i.i;,;,i„. isolated 
:i8i.'o8i>ores : with and without a gelatinous 
coat, and one- or two-celled. (After v. 
Tube\lf.) 



some species, but have a delicate stalk in others. The spores, 
eight in each a.scus, are never long and tinead-like, but always 
much shorter than the asci, ami two-celled when inalure. The 
]iara]ihvNes Iiuve button-shaped or hooked ends. 

Hypoderma strobicola - (iJostr.). Needle-blight of the Wey- 

' Kr)StIup, Forlxdltt i'liil' rsoeije/ntr or. Slii//'' squiij" s Ainjiil) pan Skor- 
Iruftruf, I8S3. 

- Ro.stiup, Forlxatti UmlffKOnjelHi i\ ISS.S. 
V. Tiilieuf, liiit. '.. Kniiidiiss il. liiiinnkiaiikh'-ih ii, 18SS ; al.sD /i,,t(tii. 
C'entralhltitl, xi.i,, Is'K). 

Noll-: When I ilfciileil to nlarc J.n/ihiii/i niiiiiin lintrhi/x/iin-iiin iiinlfr tliu 
gemiM //{//lo'lu-iiin, tliiTf alrt'iitly exi.sti-il a II ijinuli niia linwhi/s/ioruin Spi-g. 
(I.SM7). For till- fiituie I Hliall tlierefuri' call Lo/>li. Iintrln/s/xinnn KuHtr. uh 
Jl ijl>i>'li nun nliiiliiri,l(i. 



234 



ASCOMYCETES. 



mouth pine. According to the observations of Eostrup in 

Denmark, and myself in various localities of Germany, this 
is a dangerous parasite on Pinus Strohus. 
It kills the needles and young shoots, 
and may devastate whole tracts of forest. 
The diseased needles become brown in 
summer, and fall off during next winter. 
On them are produced apothecia containing 
club-shaped asci and paraphyses with button- 
shaped ends. The eight spores of each ascus 
are at first unicellular, later apparently bi- 
cellular, and enclosed in a very mucilaginous 
coat. The asci have an average length of 
120/u, the spores 20 fx, and when swollen 
28 to 30/y- 

H. pinicola Brunch.^ forms linear apothecia 
on needles of Pinus sylvestris. 
H. ericae Tubeuf." In Tyrol and Northern Italy, this fungus 

causes a disease on Erica carnea. It is common and epidemic, 

causing death of the leaves. 




Pig. 118. -Leaf of Erica 
carnea with apothecia of 
Hypoderma ericae on the 
lower surface. 1, An 
entire and a dehiscing 
ascus ; a two-ceUed asco- 
spore. (v. Tubeuf del.) 



Hypodermella. 

Similar to Hypoderma, except that the spores are pear-shaped 
and unicellular ; they occur four in each ascus, and are shorter 
than it. 

Hypodermella sulcigena (Link)'^ has four long, club-shaped, 
unicellular spores. Eostrup regards it as parasitic on Pinus 
montana and P. syhcstris, its mycelium being found in living 
green needles, and causing their death. 

Hyp. laricis Tubeuf.- This is a new fungus of tlie larch- 
needle found by Tubeuf on the Sonnenwendstein (Bavaria) in 
September, 1894. It was present in large quantity on larches 
on the upper part of the mountain, and was in every way so 
decidedly jDarasitic in. character, that there is little doubt as to 
its being an epidemic disease. The full-grown needles on many 
of the foliar spurs had died off and turned brown. The 

' Biunchor.st, Nogle norske skorsygdommt in Ber(je)ifi Mna., 1892, 
'^v. Tubeuf, Botan. Centralhlntt, xxi., 1885, and lxi., 1895. 
•' Rostrup, Fortaatte Under soegtlser, 1883. 



HYPODERMELLA. 



235 



apothecia were present on the upper surface of the ueeiUes as 
isolated black spots or united into lines : they dehisce by an 
elongated fissure. The asci are cylindrical with rounded apices, 
and measure about 110/u in length; they are almost sessile. 
Each contained four hyaline, unicellular, club-shaped spores 





Fifi.ll9.—f////.o./. ,,„■/'(/ s.'lriae.w. The 
apotbeeia form Vilack lines on the needles. 
Ascus containing four .sp-ires (enlarged). 
Single spore with a gelatinous covering 
(still further enlarged). (Cop. frOui 
Rostnip.) 



Flo. 120. — Hypodti-iiidla laricii. Larch- 
needle with apothecia on the under side. 
A, Pamphyse, and an ascus containing 
four spores. B, Isolated (enlarged) asco- 
spoi-e in its gelatinous coat. (v. Tubeuf 
del.) 



(66 yw X 16/ui with a gelatinous nunulirane. The paraphyses 
are simple hyaline filaments, shorter than tlu* a.^ei. 

Lophodermium. 

Tlie ol>long apothecia are enil)eddetl in the hust-tissues under 
a thill black cover, wliieh breaks by a long fissure. The elub- 
sha])ed asci contain thread-like unicellular sixtres, with a 
mucilaginous niembiane. The parajthy.^es are s(jmetimes septate 
and furnished with hooked or button-.'^liapi'tl eiid.s. The spores 
reach maturity on killed portions of plants, and are forcibly 
ejaculated. The foriiiatinii of pycnidia (spermogonia) ])reeedes 
that of apothecia. Many members of this genii.^^ are (h'.stnictivf 
eneiiiif-- nf ]il;iiii-. 

Lophodermium pinastri (Schrad.).' rine-Might or needle- 
cast. (Ihitaiii and I'.S. America.) This di.sease of the Scot.s pine 
(Piitus si//irsffis) i.s veiy in juiiniis in y<iiiiiL; plants, espeeially 
those in nurseries. 



Harti^', f)ii>nMi:i i,t Trrex, Eng. o.lit., Is'.t4 

I'r.intI, F/u,ii, 1S77 ; fiN<i. /•'ors/iri^^. ('< iilni/l>/'i'f, ISSO. 



236 ASCOMYCETES. 

" Casting " or premature withering and fall of needles is not 
uncommon in nurseries of pine. Amongst some of the causes 
which lead to this are •} frost, drought in winter on frozen 
ground free from snow, drought in summer on dry soil, over- 
crowding of plants in the nursery, and, finally, a " casting " due 
to fungi. 

The symptoms in the case of the present fungus are spotting 
and withering of the needles, due to the presence of a mycelium 
inside them. In early autumn, or later if the weather be dry, 
the pycnidia (spermogonia) make their appearance as little black 
prominences containing tiny unicellular conidia. The flat black 
apothecia are developed later, on first-year seedlings during 
the first autumn, or on older plants during the second autumn, 
but generally they do not appear till the third year ; they 
reach maturity on needles still attached, more frequently, how- 
ever, on fallen ones. Dehiscence consists in the rupture of 
their delicate black covering, through pressure of the swelling 
asci and spores in damp weather. The asci are club-shaped 
and contain eight thread-like one-celled spores, more or less 
twisted round one another. The septate paraphyses have a 
slightly bent point. 

Diseased seedlings die off, generally without loss of their 
leaves. Two-year-old and older plants are always weakened by 
the loss of needles, and in severe cases are killed. On such, 
the " casting " or sudden fall of all infected spurs and needles 
takes place in spring. The mycelium often makes its way 
from the needles into the tissues of the shoot, and then death 
of the whole plant soon follows. Disease of the needles of 
old trees may also occur without inflicting much damage on 
the trees themselves ; they will, however, act as centres for 
infection of younger plants, particularly those in seed-beds 
and nurseries in the vicinity. 

Confirmatory experiments on infection of pines by this 
Lophodcnnvmii were first carried out by Praiitl, later by Tursky 
and Hartig. 

The disease appears with such virulence and frequency, that 
the whole of the young pine-growth of a locality may be 
destroyed. It is thus a most dangerous disease, and at the 
same time one difficult to combat. Districts which have 

^ Holzner gives a summary of numerous theories on leaf-cast, (Freising, 1877). 



LOPHODERMIUM. 



L'37 



suffered Ijy it should, where other soil conditions permit, be 

planted with Weymouth pine {Pinvs Strohus) and the Douglas 

fir (Pseud of sv;/a Dovjjlusii), which are, as yet, exempt from 

attacks of this parasite. Infection would seem to be brought 

about chiefly by westerly winds (in Germany), which carry 

diseased leaves or fungus-si)ores from infected 

places. Large areas run greater risks than 

small patches or young trees naturally sown 

out. Seed-beds of Scots fir should not be 

placed under the drip of older trees of the 

same kind, particularly if this fungus is 

known to exist there. Shelter- belts of other 

trees often afl'ord nnicli protection from this 

disease.^ 

Lophodermium macrosporum Hartig - 
{IIi/sfr/-ii/,/t). (V.>. .VuiL-rica). Scab or rust 
of the spruce. This disease exhibits itself 
in various ways. Fre(|Ut'ntly the needles of the preceding- 
year turn brown in spring, and perithecia are produced in 



Fio. 121.— 1, Lophoder- 
hini.m )uacro»poru)ii on 
Spruce, (v. Tubeuf del.) 

2, Lophoilennium abi- 
etis on Spruce. (After 
Rostrup.) 




<r^«^ 



'if^:^':i'' 



" i ?>^ " 



-^v 



FliJ. 122. — Lophoilennium macfotporum. Section tliroUKl' H iiiiitiirc dcliiscin^' 
nix)thcciuni. (After U. Hartig.) 



summer, reaching maturity on lwii-\ t-'ar-nM needles. Again, the 
needles of tlic two-year-old shoots becunu- brnwn in aiitumn. 
and pcrithi'fia a]i]icar on tln-ni in thi- I'ollowing sninnicr, 



' I'rcvcntivc nii;iinurf.>i arc diBcussi-il in greater ilctail in I'rof. SoiiicrvillfH 
traimlatioii of Hartig'a JJi/ieaMtn of Trtm, p. 11"). 

- K. Hartij.;, \\'irh/,'<i>- Krnidlfilt ii </. W'dfillxiiuiif. Is7». 



238 



ASCOMYCETES. 



ripening in the spring of the fourth year. Or, again, a 
" casting " of brown one-year-old needles may take place in 
autunni. 

The disease is found everywhere, but in some parts {e.g. in 
the forests of Saxony ^), it is exceedingly common and very 
dangerous. The apothecia are developed as long, shining, black 
swellings on the two under surfaces of the quadrangular needles 
(Fig. 121). The club-shaped asci emit 
thread-like spores with gelatinous coats. 
The ascospores produce a strong germ-tube, 
which grows inside the needles to an 
intercellular mycelium without haustoria. 
Browning and shrinkage of the cells of 
attacked needles soon follow. The myce- 
lium also penetrates into the cells of the 
epidermis, and develops there a coil of 
hyphae, which, under a black membranous 
cover, forms an apothecium containing 
paraphyses and club-shaped asci (Fig. 
1'2'2). When ripe, the apothecia rupture 
the overlying epidermis. Little black 
pycnidia (spermogonia) may also occur on 
diseased needles.^ On needles which have 
been prematurely cast, only little spherical 
apothecial knobs will be found. 

According to Hartig, the effects of this 
fungus on the cells of attacked needles is 
very interesting. If the disease of the 
needles appears in autumn, the cells, which 
at this time are void of starch, become 
brown and die. If the disease attacks in May, when the 
needles are rich in starch, their death ensues soon, but the 
starch only disappears gradually from October onwards, as it 
is used up by the fungus-hyphae. If the disease appears in 
spring, when starch-storage is just beginning, the cells already 
attacked become quite full of starch, whereas the other cells of 
the same needle remain empty. 




Fig. 123. — Lophodermium 
macrosporum on Spnice. 
Germinated ascospores ; 

some have germinated 
inside the ascus. (After 
R. Hartig.) 



^ Nobbe, Ber. d. sdchaisches ForatvereiiiH Versammlung zu Schandau, 1891. 

^Another ascomycetous fungus — Naevia pinipen/a Rehm — occurs alone or 
together with this species ; Rehm regards it as parasitic (Hfdivi(jia, 1892, p. 802). 



LOPHODEIIMIIM. 



239 



Lophodermium nervisequium (I). C.)^ (U.S. America). This 
very common fungus attacks both old and young silver tirs. 
The needles die after becoming brown, and remain for a long 



1/ 



1 li 

Fio. 124. — LophoiJermium nervitequium 
on Abies pectinata (Silver Fir). 1, Under 
surface of needle with apothecia. 2, 
Upper surface with pycnidia. 




Fio. 125. — Lophodermium nervisequium. Section 
of a needle of Silver Fir. b, Pycnidium on 
upper surface shedding conidia. n, AjKJthe- 
cium on the lower surface. (After R. Hartig.) 




Fig. 126. — Lophodermium neiviiequiuiu on Silver Fir. Portion of a riiH; aiH>the- 
ciuna. an. Filamentous paraphyses ; rod-like ccIIh (conidia V), *•, abjointol from 

the anex of tllt; Ii:ll*:inli\'u«*w * tln^ ii..ci c.^fttitiii «>iirltf uik.kr.>u ^ifuiiit liolf .1.J l..ii.r .... 



the apc.\ of the paraphyse.s ; the a.<>ci contain ei^'ht xporcH alMiut half a.s lonK an 

**■" "° i»-.if^ f,„ir riccupying the upper half, four tliu lower ; r, a rudimentary 

nature HjKjres i)<>M.fe«.s a j{elalinoii8 coat, otherw do not ; Hporeii 



the asciiH it.self 
ajtcug ; Home m 

CMC 



MKus , Mome mature HjKjres i)<.M.fe«.s a j{elallnoii8 coat, otlierx do not ; sporeii 
BKcaiK; l.y an apical opening. <■, or by rupture of the luk-us, /; two germinating 
<|)orfM are also shown, one with a gelatinous coat, the other without. (.After 
H. Il.irtig.) 

time liaiigiiig (111 the Iwig.s. Tbr ilisi'a.se varies in its tU'wlnj)- 
mt'Ut nil the muiintains and lnulaiuls, according lo cliniaiii" 
coiulitions. 



'I!. Miiltij,', \Virhli[l> Kimikhe it'll, Is74. 



240 ASCOMYCETES. 

The mycelium lives intercellular, and produces the same 
effects on the cells of the fir-needles as those of Loph. macro- 
sporum on the s]3ruce. The mycelial hyphae penetrate into the 
epidermal cells and form a cushion, which bursts the epidermis 
and gives rise to numerous straight conidiophores, with very 
small, oval, unicellular conidia. The apothecia are developed 
while the needles are on the tree or after they have fallen ; 
they form shining black stripes on the middle nerve of the 
lower surface of the needle (Fig. 124). The thread-like spores 
have a mucilaginous coat, and are ejaculated from club-shaped 
asci (Fig. 126). Pycnidia (spermogonia) are often produced 
before the apothecia as long wavy bands on the middle nerve 
of the upper surface of the needle (Fig. 125). 

L. juniperinum (Fries.) (Britain and U.S. America). A 
common species on dead needles of Juniper communis, also on 
needles on the branch : I have, however, never seen it in such 
mass as to believe it to be a dangerous parasite. 

L. gilvum Eostrup ^ attacks and kills living needles of the 
Austrian 1)lack pine. 

L. laricinum Dubv. The pycnidia and apothecia of this 
fungus are common on dead needles of larch, but parasitism has 
not been proved. 

L. abietis Eostr. A species found by Eostrup on needles of 
spruce, causing yellow spots and then large black points (Fig. 
121,2). 

DISCOMYCETES. 

The Discomycetes have an apothecium of varying shape, but 
always more saucer-like than spherical. The ascocarp, at first 
a closed structure, opens sooner or later and exposes the 
hymenium. The apothecium is composed of two distinct portions 
of mycelium. The essential part, often called the hymenial 
layer, consists of hyphae which give rise to the asci. The 
remaining portion of the ascocarp forms a support or envelope 
for the hymenium; it consists of a pseudoparenchyma, and may 
be differentiated into a sub-hymenial layer or hypothecium wHth 
its hyphae interwoven with those of the hymenium, and a 
lateral portion or excipulum usually more or less cup-shaped. 

1 Rostrup, Fortsatte Undersoeijelser, 1883. 



DISCOMYCETES. 2-tl 

The paraphyses are developed t'luia llie mycelium of the 
envelope and occupy the interior of the ascocarp, while the 
asci arise later from the ascoj^enous hyphae and force their way 
in. The formation of asci and parai)hyses may go on for a 
long time. Periphyses are not produced. 

The Discomycetes include five divisions, the Phacidiaccae, 
■Stictidrac, Trijhlidicar, Drrinatcacciw, and Pczizc<ir. Many of 
the species included in these ai-e parasitic on cryptogamic 
plants to form lichens, the majority are saprophytes, and only 
a few isolated groups are true parasites on higher plants. The 
latter belong to the Phacidiaccae, Dermatcaceac, and Pezizcae. 



(1) PHACIDIACEAE 

The apothecia are black and ihick-walled, at tirst embedded 
in their substratum, but later breaking through it. The asco- 
genous layer is spread out on a delicate Hat hypothecium. 
The black apothecia of the species of Pltavidium are frequent 
on leaves and needles. lielim divides the group into two 
families : the EtipJiacidicac and the Paiudophacidicae. 

EUPHACIDIEAE. 

The apothecia are embedded in the tissues of thi' host : the 
su})erincumbent layers of the sul)stratum forming t)ver them a 
blackish memliranous plate, which is ruptured into lobes and 
exposes the black apothecial disc. 

Phacidium. 

The apothecia are fused with the superincumbent layers of 
the host-plant, and the black cover so formed is split into 
.several lobes. The club-shaped asci contain eight colourless, 
unicellular, ovcjitl or sj)indle-sliaped spores. The i»arapliyses 
are filamentous. The poic of the aseus is coloured l)lue by 
iodiiir. 

Phacidium repandum I'l. (Ilrilain). Occurs on living leaves 
and stems of .Isjtini/n inldrnhi , i,'ii/iiiiii nm/hif/o, and other 
Ituljiaceae. The pycnidial fnim is probiibjy I'/ii/lhic/tora 
pu/irfiforiiiis Vr. 



242 



ASCOMYCETES. 



Schizothyrium. 

The roundish or oblong apothecia dehisce by lobes. The club- 
slia])ed asci contain oblong, hyaline, two-celled spores. 

Sch. ptarmicae Desm. (Britain). This occurs as a parasite 
on living green leaves and stems of Achillea Ptarmica. The 
apothecia form little black points, which on rupturing break 




Fig. 127. — Schizothyrium 2)tarmicae ou Achillea Ptarmica. (v. Tiibeuf del.) 

up the epidermis into lobes. The thick asci contain two to 
four large two-celled spores. Paraphyses are present. A pycnidial 
form is known as Leptothyriuin ptarmicae (Sacc). 



Rhytisma. 

The fungi of this genus live in the tissues of living plants and 
form sclerotial cushions as isolated black spots. In these places 
the pycnidia are developed, and are followed by apothecia after 
the death of the leaves. The apothecia open by a fissure, and 
contain thread-like paraphyses and club-shaped asci with eight 
needle-shaped spores, which are septate when mature. 

Rhytisma acerinum (Pers.) (Britain and U.S. America). 
Tow^ards the close of summer, the large black spots caused 
by this fungus on leaves of various species of Acer (sycamore 
and maple) are by no means unconnuon. Pycnidia {Melasmia 
acerinum Lev.), containing little unicellular conidia, are first 
produced under the cuticle, while the epidermis and under- 
lying cells become filled with mycelium till a black selerotium 



RHYTISMA. 243 

is completed. In the following spiing, the sclerotium-spots 
on the fallen leaves have become thicker and superficially 
wrinkled. At this stage the apothecia are produced, and 
dehisce by fine elongated fissures ; they contain club-shaped 
asci and thread-like paraphyses with hooked ends. The thread- 
like ascospores are ejaculated with considerable force, and reach 




Fifi. 128. — Bhytitma acerinuiu. Two apothocial cu.shionB on leaf of Jeer 
caiajKntre in first summer. A, Loaf-;ipex of Acer jiliildiioiJeii with tlio mature 
a|M>thccial cviHhiunM aw Hcen in tlie second summer, witli their cliaracteristic 
wavy markintf. (v. Tulxiuf del.) 

maturity in ^fay or June. According to Klcltahn,^ the sjtores 
have a mucilaginous mcmbiaiie, liut this docs not throw much 
light on till! problem of how they reach the Jeaves of trees; 
wind, however, would .seem to be the agent for distribution. In 
lhre<' weeks after infection, leaves show yellow spots ; in eight 
weeks the pycnidia appear. 

^ Bold II. Ciiitinlhlnlt, I. VIII., I.SiH, |». '.Vl\. 



244 



ASCOMYCETES. 



The disease is best combated by prompt removal of fallen 
leaves in autumn; where this rule is followed Rhytisma is seldom 
found (see p. 71). 

Rhytisma punctatum (Pers.) (Britain and U.S. America). 
Whereas the spots of the Rhytisma just considered are large, 
those of this species seldom exceed a few millimetres. They are 




Fig. 129 — Rhytisma punctatum. Leaf of Acer Pseudo-platanus with apothecia ; 
the leaf is yellow, but the spots enclosing the apothecia are still green, 
(v. Tubeuf del.) 

black in colour, angular, and scattered over the whole leaf- 
surface. After the leaf has turned yellow, portions of it sur- 
rounding spots of this Rhytisma retain their green colour, so 
that we have black spots on green islands in the yellow leaf. 
The sclerotia dehisce by valves. The apothecia contain thread- 
like paraphyses and asci. The asci are club-shaped and contain 



RHYTISMA. 



•245 



eight needle-shaped unicelhilar spores ; pycnidia (spermogonia) 
with little unicellular conidia are also formed. 

The fungus attacks leaves of sycamore {Acc7' Pseudoplatanvs), 
the black spots making their appearance in September. The 
apothecia ripen on the ground during the following summer.' 





Fif;. l.'}0. — Sections of Sluple leaves 
shuwinii; the upper epidermis ruptured 
by 1, JihytUma acerinn.m ; 2, liUytitina 
punctatuiii. 



Fig. 131. — Khytitma lymmdrieum Mdll. Two 
leaves of Salix purjnirea with stromatit. A, The 
upper side, li. The lower side. C, l.un)^tti<Iiii:il 
sectiiiii tllro^I^ch the same leaf, showing numerous 
iipothecia on the upper side, fewer ou the lower ; 
the shaded middle part represents leaf-tissue, 
the remainder is the lis'ht fungal stroma in 
which the darker aixitlaecia are emlx-dded. 
(V. Tutxruf del.) 



Rh. salicinum I'lts. (I'.iiiain ami I'.S. Auu'rica). Thickunud 
black wrinkled .sp(jt.s appear fre([uc'iitly on living leaves of various 
Species of willow, './/. Salir Ciqnra, S. ciiuirn, etc., also on some 
alpine willows, (.//. *S'. reticulata. These contain a])othecia of this 
funmis, whicli reach their full luaturity during the second 
summer. 



' liymotnyrojinis rhylismoidi s Almll. IMaok spots Himihii- l(» tliosi- of lihi/ti^ina 
appear on the leaves of sycamore. 'I'lie Mack eru8t« are here only Hiiln-uticular 
atnl enclose a transparent tissue from which lar;,'e spherical (fj)oreH are pruducetl. 
The syHtematic |>osition of tliis fnn^^iis is unknown. 



246 ASCOMYCETES. 

Rh. symmetricum J. Mliller {Rh. autumncde Schroeter)^ is a 
form occurring on Salix purpurea and recently separated as a 
distinct species. This willow, one of the best for cultivation, 
may often l3e seen with its leaves covered with black spots, 
and the disease may spread over every tree in a nursery. 

The apothecia are found on the upper surface of the leaf, 
on black, shining, and much wrinkled cushions. In addition, 
black apothecial cushions are developed on the under surface 
of the leaf, which is not the case with any other species of 
Rhytisma. According to Schroeter, the spores ripen in autumn 
on still living leaves. 

(This species may be synonymous with Rh. australe Dur. et Mont, on 
Salix purpurea in Algeria.) 

A species which causes little thick cushions on Salix Caprea has been 
called Rhytisma umhonatum Hoppe. 

Rh. andromedae Pers. occurs on leaves of Andromeda polifolia. (Britain 
and U.S. America). 

Rh. empetri Fries, on leaves of Empetrum nigrum. (Britain). 

Rh. juncicolum Rehm on Jiincus Hostii. 

Rh. urticae Fr. on stems of Urtica dioica. (Britain and U.S. America). 

Rh. bistortae D. C. on Polygonum viviparum in France, Greenland, and 
America. 

PSEUDOPHACIDIEAE. 

The apothecia are at first embedded in their substratum, 
under the superincumbent layers of the host-tissue, and form 
blistered patches ; on rupture, this cover forms a rim round 
the apothecial cushion; the excipula of the apothecia themselves 
are membranous, generally black, and dehisce by lobes or 
fissures on the apex. 

Cryptomyces, 

The apothecia break out from the substratum as black crusts. 
The asci contain eight oval, unicellular, colourless spores. The 
paraphyses are thread-like and septate. 

Cryptomyces maximus Fries.^ (Britain and United States). 
This fungus lives parasitic on twigs of various species of willow, 

'J. Miiller, "Zitr Kenntniss d. Runzelschorfs," Pringsheim,'s Jahrhuch, 1893. 
Schroeter, Flora v. Schlesieii, 1894. 

Both appear to be identical with lih. amphiyenum Wallr. {Flor. Crypt, ii. 412). 
- Tulasne, Select, fimgorum Carpologia, in. 



CRYPTOMYCES. 



24; 



especially Salb: incana, Itut also on *S'. pvrpinra. When the 
black apothecial cushions 1»reak out through the bark, the twigs 
of the liost-plant are frequently still green and leaf-clad. 

The apothecia originate in the lower bark and S(j loosen 
the epidermal layers as to cause the appearance of yellow spots. 
Black centres appear in the spots, due to the formation of a 





H 




2 3 4 

Fio. 132. — Criiplomyces vwximuK. 1, ('n)s.s-.sct'tioii nf a twi>{ iif S<i(i.r iitcHiic, 
with stroma a b ; the niyccliuin occupies the rind ami iM.st into tlio cuinliiiini, so 
that a woo<l-rin(f for the current year lias been only partially develojied ; the 
shaded psirt between a and h ih an aenitinKtisHuo. formed of loose hyphae, wliicli, 
with a, forms the stroma proper; '-, the a.sco>{en<pus layer. (J^ens-niUKnitication.) 
2, .Xsei, showing a dry ascus ; one to which water lias been added, so that it is 
elont^ating ; one ruptured and ejaculating 8|iores. 3, Younf( stromata iti spring, 
still covered by the epidermis of the Stilix. 4, Willow twig after dctachnicnt of 
the jKitohes of C-iiptoiiii/rrA in autumn, (v. Tulieuf del.) 

black a]»olhecial cover uiidrMifaili the ciiidrriiiis. ( )ii rujiiun' 
<i|' the cpidi-niiis, black ajiiitht'cial ciishiniis i'Iiutl;!' and coni'i- 
large areas of the living iwig.s. Kain causi-s the a]Mitht'cia 
to become gelatinijus, and t(i swcdl considerably : nn dryin^^ 
the ciishiniis ritll u)i ami tall oil', lra\iMg sears in the bark 
(Fii,'s. l;;2, 4). 



248 ASCOMYCETES. 

A longitudinal section through a cushion exhibits a thick 
hypothecium, consisting of a close pseudoparenchynia of hyaline 
fungal cells, which permeate every tissue of the bark and cause 
death of the cambium ; above this comes a looser layer with 
many air-spaces, and over this the layer from W'hich the asci 
and paraphyses arise. 

The asci contain eight oval unicellular spores with distinct 
cell-nuclei. When a section is placed in water, a very 
evident swelling takes place, and the asci elongate to twice 
their original length. I have not observed ejaculation of 
spores, but rupture of the asci occurs in water-preparations 
and the spores are set free in large numbers. The spores 
probably germinate and infect young shoots, the mycelium 
hibernating there. 

The effects of this fungus are death of diseased twigs of 
willow above the spot where a sporogenous cushion is 
formed. 

This species is also said to frequent Cornvs in America. 

Cryptomyces pteridis (Eebent.) occurs on fronds of PtcrU 
aquilirui, but whether a parasite or not is as yet uninvestigated. 
The asci ripen after the fronds have passed through the winter. 
To this belongs the conidial form Fusidimn 'pteridis Eabh. 

Clithris. 

The apothecia, at first spherical, become oblong, and break 
through the superincumbent layers by a lobed fissure. The 
apothecial disc is oblong and fiat. The club-shaped asci contain 
eight hyaline spindle-shaped or thread-like spores, with one or 
more cells. The paraphyses are thread-like. The majority of 
this group are saprophytes. 

Clithris (Colpoma) quercina (Pers.) (Britain). According to 
Schroeter,^ this causes disease and death of living branches of 
oak. The oblong apothecial discs are greyish-white, and covered 
at first by a brownish-grey wall which, later, becomes ruptured. 
The ascospores are simple. Cylindrical pycnidia, with somewhat 
bent conidia, are also produced. 

CI. juniperi (Karst.) occurs on living twigs of juniper. Nothing is 
known of its parasitism. 

1 .Scln-oeter, Pilze Schlesieit", 1893. 



DOTHIORA. 24^9 



Dothiora. 



The spherical apothecia are t'liiliedded in the substratmn, which 
they rupture into lobes, while they themselves dehisce Ity 
irregular fissures. The club-shaped asci contain eight colourless 
or yellow, club-shaped or spindle-shaped, nuilticellular spores. 
Paraphyses are never present. 

Dothiora sphaeroides (I't-rs.) is regarded by llostrup as the 
cause of a tlisease of the Lunibardy p(jplar {Populus 2\>/''((^iiiif('Jis), 
in which the branches, particularly those of the upper part 
of the tree, die one after another till all are gone. The spores 
are club-shaped and constricted at the middle ; each half is 
divided by four or five cross-septa, and each cell so formed 
is again suljdivided by u longitudinal septun). 

Yuillemin ascribes the same disease to l)idiimo>tphacria 
pcqmUna A'uill. (see p. 218). 

According to Kehm, Dd. sphacruidis also occurs on Fojmh's 
t/rmi'/a, and is distinguishable from Do. rnvtilii (Fr. ) on Itdth 
Populus italica and F. trcinula. 



Heterosphaeria. 

The spherical apothecia are at first emliedded, but later emerge 
through the covering layers and dehisce, their apices breaking 
up into teeth-like lobes: they are dark-brown or black in colour. 
The asci are club-shaped and contain eight spores, wiiicli are 
colourless, oblong or club-shaped, and consist of one, two, or 
four cells. Iodine colours the pores of the asci blue. The 
para]ihysos are colourless and thread-like. 

Heterosphaeria Patella Tode). (I'.riiain and C.S. America.) 
The asci contain eight bicellular spores. Tlie paraphyses are 
thread-like and se]itat(', some lieim,^ forked or branched : they 
bear scalpel-shaped coiiidia. 

The mature apotliecia are found chielly on the stems of 
\arious UuiliiUifrriii\ i.ij. Thnnus Ciirntn, Auiflnnn i^nnro/ins, 
Peiriisiluiuui sdfiruiu, Pustiiiiitu, etc. \ xarii'ty oljiistris occurs 
amongst the mountains on Htmclruui Sjihunihiliinn, also on 
(li iitiii no Infill, Vrrntruui ririilc, etc. Kelim and others lielieve 
that the fungus attacks living i^n-en parts of plants, .md leache-s 
in;iiuiity in tin- fojlowinu' \<'ar on tlif killed orijans. 



250 



A8C0MYCETES. 



Scleroderris. 

V A black stroma is formed in the bark of twigs attacked 
by this fungus, and thence the apothecia break out in great 
numbers, at first as closed spheres, later as stalked open 
cups with finely lobed rims. The asci are cylindrical or club- 









Fl(i. ISi.^^^cleroderns fuliginosa on living twig of Salix alba. 
A, Three apothecia, two in section, the third seen from above, 
showing the cross-like fissure. B, Sections of diseased branches, 
whose growth has been arrested in the shaded parts ; on the 
dead bark apothecia are present. C, Asci, spores and paraphysos. 
(v. Tubeuf del.) 



Fig. Viz.- - Scleroderris fuli- 
dinosa on living twig of 
Salix Caprea. (v. Tubeuf 
del.) 



shaped, and contain eight colourless spores which are club- 
shaped, needle-shaped, or thread-like, and divided by septa into 
four to eight cells. The pores of the asci are coloured blue 
by iodine. The paraphyses are thread-like. 



SCLERODERRIS. 251 

Scleroderris fuliginosa (Fries), (liritaiii and U.S. Ana-rica.) 
This was considered l" 1m' a saprophyte till my attention was 
directed to its injurious nature. It occurs on living branches 
of Salu: Caprm, S. triandra, S. alba, etc., and brings about 
their death. The black crusts, on which the apothecia develop, 
appear both on weakly twigs and strong branches. The my- 
celium makes its way through the tissues to the cambium, which 
it kills, causing this and neighbouring parts to become brown. 
Adjacent parts, as yet unattacked, continue at first to grow in 
thickness, but they too are gradually killetl. As a result, the 
twigs attacked grow irregularly according to the extent and 
number of diseased places (Fig. 134); and when all or most 
of the lower tissues of a twig are killed, the higher parts 
die off with their leaves. Wherever the fungus appears, many 
trees are generally attacked. 

Sc. aggregata (Lascli.) dfvelops on the living stems of Rln'nantliaceae 
anil inatint- ipu the dead. 

Sc. ribesia (Per.s.) is a eoninion species on twigs of red and hlaek eui rant, 
Ijiit wht'ther parasitic or not is unknown. 

(2) DERMATEACEAE. 

The apothecia are developed at first either under the sub- 
stratum or altogether supertieially. The ascogenous layer 
e.xtends over a thick hy[)otIieeiuni. 

The Dermateaceae contain the Cenangicar, iJi rtnatatr, Vatd- 
Id.ridciiir, and Buhiariaccac. 

CENANGIEAE. 

Apothecia at first embedded, then exposed. They are sessile, 
clavute or cone-.shaped, and broaden out to discs on opening. 

Cenang-ium. 

Apothecia glolii>>e; on dehiseence at first cup-sliapeil, but 
afterwanls flatter and more saucer-shaped, with entire margins; 
they may occur singly or massetj togetlier. The elulp-sliainMl 
asci contain eight colourless, oblong, unietdlular spores, ,ind 
filamentous ]taraphyses with lhiekem'(l apiifs. 

Cenangium abietis ( I'ers.). (Ih-itain and I '..s. America. ) This 
fungus is usually a sajtrophyte, but Thunien su^^ests it as an 



20'2 ASCOMYCETES. 

occasional parasite. Schwarz^ has recently described it as 
attacking pines, weakened by an impoverished water supply to 
the twigs and by other unfavourable conditions. It appeared 
for a time as an epidemic in the pine forests of Germany, but 
very soon disappeared again. 

The symptoms of disease were, withering of twigs in spring 
from the apex downwards into the region several years old. 
The epidemic had been previously noticed in the spring of 
1892, and was described by Hartig, who, along with Kienitz, 
regarded it as a result of the long dry preceding winter. The 
disease has never been observed on pines under five years old, 
and serious injury only results when the fungus is accompanied 
by damage done by insects. The apothecia containing the asci 
are generally produced only on dead twigs and needles. 

Schwarz regards as a conidial form of this species, Brun- 
chorstia destruens Erikss., wdiich will be described in greater 
detail amongst the " Fungi imperfecta " In addition to Brvn- 
diorstia, other pycnidia with unicellular conidia occur. 

DERMATEAE. 

The apothecia, at first spherical and embedded in their host, 
break out in clumps; they are generally short and thick-stalked, 
and open to form a roundish saucer-shaped disc with an un- 
broken rim. The hypothecium is thick and often coloured. 

Dermatella. 

A stroma is developed under the bark of the attacked parts 
of the host, and in it originate dark brown apothecia with 
short thick stalks. The bark is ruptured and the apothecia 
emerge as flat, expanded, saucer-shaped discs with a complete 
rim. The asci are club-shaped and thick-walled. The spores, 
at first unicellular, later multicellular, are large and colourless 
or brownish. The paraphyses are septate and generally forked ; 
they often form a coloured epithecium. 

Dermatella prunastri (Pers.) (Britain and U.S. America). 
According to Ludwig, this lives as a parasite on the living 
bark of plums, apricot, sloe, and other species of Primus. 

^ Schwarz, Die Erkrankumj <l. Kief em dnrch Cenaiujinm uhietis, Jena, 1895. 



DEKMATELLA. 253 

Apothecia and pyciiidia {Sphacroncma spvrivm Fr.) are both 
developed. The ascospores are one-celled and hyaline. 

[Wagner' adds tlie following species found liy liini in Sa.xony as more 
or less marked [larasites : Edit. 

Dermatea (Pezicula) cinnamomea (Pers.) on (^nei-rus. It attacks the 
rind in jdaces injured by deer, and causes injury to the trees. 

D. (Pez.) carpinea (Pers.) kills many young hornbeams ; it probably 
obtains entrance through wounds. 

D. (Pez.) acerina Karst. is a doul>tful parasite on Arer Pse^idoplatanHs.^ 

BULGARIACEAE. 

Bulgaria polymorpha Wett. {B. inquinaiis Fr.) (Britain and U.S. 
Ameiioa). A dangerous enemy of the oak,- causing death. Researches 
into its parasitism are still wanting. The sporocarps develop on dead 
bark, especially of beech. 



(3) PEZIZKAE. 

The apothecia are never embedded, but appear as saucer- or 
cup-like structures on the substratum ; they are tleshy or waxy, 
and often of bri,L(ht colour. The hypothecium is very strongly 
developed. 

The families included in this group are : MoUisicac, Hdotieae, 
Eiqiczizeac, and Ascoholeac. Of these, all except the last con- 
tain parasitic forms. The Mollisieae and Hcloticac contain also 
a number of lichen-fungi not considered of sufficient practical 
value to be included here. The Ascoholcar live as saprophytes on 
animal droppings. 

MOLLISIEAE. 

The apothecia generally sit free throughout their whole 
existence on a close, firm suljstratum of hyphal tissue, or they 
may be sunk in the host and break out later ; they are at 
first closed and spherical (rarely tapering downwanls), but after- 
wards open and expose a cup-like, saucer-shaped, or Hat disc of 
asci. The disc is waxy and soft; externally it i.s brownish 
and generally smooth; exceptionally it niay be dnwiiy nr beset 
wilb .^liurl liaiis nr biistles. The s]M»rne;ir|ts art.' iimwu and ((iin- 

^ZiitHch. /. /'jlditzmhiankli^i/'ii, IH'JO, p. 7(i. 

-Luilwig, (JinfrrUh/aU /. Iia<:li rioloijie u. Partuntrnkumlr ; iilso, Lrhrhurh (/. 
n itdi- re r K ryjtfo'jd iiiiii . 



254 ASCOMYCETES. 

posed of pseudoparenchyma, which, towards the margins, becomes 
more elongated and prosenchymatous. Hypothecium generally 
poorly developed. 

Mollisia. 

The sessile brownish apothecia on opening generally exhibit a 
flat, saucer-shaped, transparent stratum of asci. The spores are 
unicellular, hyaline, and spindle-shaped or club-like. The 
paraphyses are hyaline or coloured, sometimes forked. 

Mollisia Morthieri (Sacc). The apothecia are developed on 
yellow spots of the lower epidermis of living leaves of Rvhvs 
Schleicheri and B. fruticosus. The young apothecia are reddish- 
brown and spherical ; when open they form yellowish-brown 
discs with very delicate margins. The asci contain eight 
spores, arranged in two rows. The spores are unicellular, club- 
shaped, and colourless. The paraphyses are colourless or 
brownish, with slightly bent points. 

Niptera. 

Apothecia as in Mollisia. The spores, however, on com- 
pleting their development are two-celled. 

Niptera hypogaea (Bres.).^ Found by Bresadola in Southern 
Tyrol, underground on the roots of Adenostyles albifrons. The 
apothecia are massed together on brown hyphae in blackened 
parts of the host-roots. The ascogenous disc is greyish-brown 
or whitish, with fine fibrous margins. The asci are spindle- 
shaped, and contain eight spindle-shaped colourless spores, 
which are at first one-celled, later two-celled. The septate 
colourless paraphyses are forked. 

Pseudopeziza. 

The members of this genus live as parasites in the leaf- 
tissue of higher plants and produce dead brown spots, in which 
the ascocarps are afterwards developed. The apothecia have 
delicate walls, and, after rupturing the epidermis, emerge 
as delicately-coloured saucer-like hymenial discs. The club- 
shaped asci contain eight spores, arranged in two rows. The 

^Bresadola, Fuwji trident, A. lxxv.. Fig. 1. 



PSEUDOFKZIZA. 20^ 

spores are ovoid or elliptical, colourless, and unicellular. The 
colourless paraphyses have thickened apices, rarely forked. 

Pseudopeziza (Phacidiumi trifolii (Bernh.). Leaf-spot 
disease ut the cluvei. This disease appears on the leaves of 
various species of clover in Europe and America ; its attacks 
may attain considerable severity, and intiict great injury to 
crops. The leaves become spotted, and finally die off. The 
apothecia occupy brownish-yellow di.scs on the surface of the 
leaf, and hence are not unlike pustules of a Fucciuia. The asci 
are club-shaped, and contain eight ovoid, unicellular, colourless 
spores. The paraphyses have broadened apices, rarely forked. 
A conidial form {Sphcuronema pliacidioides Desm.) is generally 
allocateil to this species. 

Ps. trifolii \^vai: medicaginis) (Lilj.) is foiiiul on species of Medicago 
(Britain and U.S. America). 

Ps. bistortae (Lib.). Tliis occurs on the lower epidermis of living leaves 
of Polyijoi'iiiii lii.'itorta, and P. viriparinn, causing dark-brown swollen 
spots where the apothecia are developed. Juel ' has transferred this species 
to the Ph(n-idiiicfnt', and named it Pseudorltytismu histurtae (D. C). 

Ps. alismatis Phill. et Trail) causes spots on leaves of AUsma Plantatjo 
(iJiitiiiii). 

Fabraea. 

This genus is distinguished from Pscv.doin'ziza by the spores, 
which, though at first unicellular, become two or tour-celled. 
The species ai'e parasitic in the leaf-tissue of higher plants. 

Fabraea astrantiae (Ces.). The mycelium lives in the leaf- 
parenchyma of AsfnnitiK major and A. carniolica, causing dead 
spots. A form occurs on Saninda curopaai. 

F. ranunculi TFries.) (Ibitain). The apothecia o'i this are 
Very common on blown sp(jts on the leavi-s of \arious species 
of lianuncidi's. 

F. cerastiorum fWallr.) frequents leaves ot irrfi.'<tiinn (Britain)- 
F. Roiisseauana (Sacc. et Bomni.) occurs on leaves of Cuft/iu /ni/untris. 
(A 15i ili-^h spcciis if syiionyinuus with /'seiidopezua calthne Mas.s.). 

Beloniella. 

The gregarious ajiotheeia are at tiisi eiidu'dded. but liri-ak 
out later. M.xteniaJly thi- apothi-eia! iliscs aie roUL;h, (h\rk IiroWM, 

' .Uv/-.'/. n-iir. Wl.ush.Ahui., is'.u. 



256 ASCOMYCETES. 

and striped, the margin being fibrous. The asci contain four 
to eight spores. Tlie spores are generally ovoid or spindle- 
shaped, at first unicellular, but divided later into two to four 
cells by means of cross walls. The colourless paraphyses 
have thickened club-like apices. 

Belionella Dehnii (Rabh.).^ This parasite covers stems 
and leaves of FutcntiUa norcegica, and is distinguished by its 
sharp, spindle-shaped, bicellular spores. 

HELOTIEAE. 

The apothecia are generally quite superficial ; less commonly 
they are at first embedded, and emerge later ; or they may 
develop from a sclerotium. In form they are spherical, cup- 
shaped, or top-shaped, and a stalk of some kind is generally 
present. On opening, they form a cup or flat plate, on which 
the hymenium lies exposed ; the cup is soft or waxy, and 
enclosed in a delicate wall, which is externally either smooth 
or hairy. The sporocarps consist of a pseudoprosenchyma 
(after Eehm). 

Sclerotinia. 

The sclerotia ^ give rise to smooth-stalked ascocarps with the 
form of beakers, funnels, or saucers. The stalks often produce 
rhizoids. The asci contain eight unicellular hyaline spores, 
elliptical or spindle-shaped, and of equal or unequal sizes. 
The paraphyses are thread-like. In several families couidia are 
formed before the sclerotia. Some forms are heteroecious. Most 
of the species are parasitic on plants. 

The Sclerotium diseases of the Vaccinieae.'^ 

These are a well-known group of sclerotium diseases, and 
amongst them the following have been named as species. 

Sclerotinia vaccinii Wor. {8cl. Urmila Weinm.). The 
sclerotium disease of the cowberry. The young shoots and 

^Figures in Hediviyia, 1881. 

-Literature: De Bary, " Uebereiuige Sclerotien u. Sclerotienkrankheiten," 
Botan. Zeitunfj, 1886; ii\s,o Morphology and Bioloi/y o/the Fungi, English edition. 

Brefeld, SchimmdpUze, Heft. iv. u. x., and Botan. Zeitung, 1876. 

Saccardo, Sylloge, Vol. viii. 

'^Wovoxiin, Mem. deVacadem. imp6r. d. sci. d. St. Petersburg, vii. Ser. , t. 36, 1888 
(with tea plates) ; also Bericlite d. deutsch. botan. Ges., 1894. 



SCLEKUTINIA. 



1.'t7 



leaves of Vaccinium Vitls-Idara exbiliit in spring a mould- 
like coating, consisting of chains of lemcju-shaped conidia. 

Woronin thus describes it : " In the outer layers of the cortex, 
amongst the dying elements, a pseudoparenehymatous cushion is 
formed, from which simple or dichotomously branched hyphae 
grow out through the overlying cuticle. The individual members 
of the chains of conidia are separated from one another by a 
spindle-shaped piece of cellulose — 'the disjunctor.' " 

The disjunctor spoken of here is a spindle-shaped cellulose 
body found between the single conidia ; it easily breaks across 
and so facilitates the breaking up of the chains of conidia 




Fl((. 13o. — Sclti-ntinia roccinii on I'acciniutn f'itU-ldi'tti. MuiuiiiificMl Cowburrifs 
in fresh condition and in the following May, iiftcr development of /'ecicd-cvips. 
A, Chuin of coiiidin united by disjnnetors. B, (ierininating conidiuui after treat- 
ment with iodine ; the plii«ina has shrunk, but remains connected with the 
sixjridia in process of abjunction. (After Woronin ) 



(Fig. loo). It has its origin as follows: Tiie coiiitlia at lirst lie 
closely end to end, enclosed in a delicate primary mciidtrane ; 
the partition-membranes split into two lamellae, each of which 
takes part in ihc formation of a ct'llulose body which gratlually 
Ijecomes spindle-shajjed. In the course of its growtii this cellulose 
body — the di.sjunctor — ruptures the [)rimary enclosing membrane, 
and, being released, becomes more elongated, so that the conidia 
an- puslied away from each other and fall apart. 

The conidia have a strong characteristic odour u[' almonds, 
atliactivc to insects, wliich carry olf the conidia and tlust them on 
the stigmata of (tthcr ]'iuriniiiin flowers. AN'ind is also, in all 
pnjbaltility, an a^eiit in the distribution of the conidia. Tiie 

i; 



258 



ASCOMYCETES. 



conidia germinate and give off' long septate hyphae which, follow- 
ing the course of the pollen-tube, reach the ovary, and soon 
fill all four loculi with a w^hite mycelium. The growth of this 
mycelium proceeds from the central axis towards the walls, and 
forms a hollow sphere open above and below. The diseased 
berries cannot be distinguished till ripe ; then, whereas the 
normal are red, the diseased are yellowish-brown to chestnut- 
coloured, and soon shrink up, leaving only the outline of the 
sclerotium. 

The dead or mummified berries fall prematurely, and lie over 
winter on the earth. In April or May, the sclerotia give rise 




Fig. IZC^.— Sclerotinia oxyeocci on Vaeciniv.ia Oxycoccns. Young shoot of Cran- 
berry with mature conidial cushion and diseased upper leaves. A, Fcziza-cwp 
developed from a sclerotial fruit ; numerous rhizoids proceed from the base of the 
stalk. B, Ascospores In stages of germination. C, Conidia in germination, with 
remains of disjunctors still attached. (After Woronin.) 



to several primordia or hom-like stalks, on the extremity of 
which an apothecium is afterwards formed. Ehizoids are pro- 
duced at the base of the stalk and attaching themselves to the 
ground act as supports and organs of nutrition. The apothecia 
contain both asci and paraphyses ; the latter are septate, dichoto- 
mously branched filaments, with club-shaped ends, and coated 
with a brown resinous substance. The asci have a canal at 
one end through which are ejaculated eight spores of almost 
equal size. These produce sporidia in water ; in nutritive 
solutions, however, they form a septate mycelium with conidia. 
The ascospores bring about infection by means of one or two 
germ-tubes which penetrate the outer memljranes of young 



SCLEUUTINIA. 



259 



cowberry shoots, the stoinata being always avoided. In less 
than three weeks conidia are produced. 

The mode in which the germ-tubes attack the host-plant is 
very remarkable. Woronin says : " The germ-tubes developed 
from the ascospores grow inwards towards the vascular bundles 
of the host-plant and enter them ; then they continue to 
develop, but now in the opposite direction from the interior of 
the plant towards the periphery. Here a peculiar phenomenon is 
exhibited, the fungus exerts its injurious effects on the surrounding 
tissues of the host-plant, then, having killed these, it utilizes 




n\ 



T&4^^ 




C D li 

Fifi. 137. — Sclerotinia liaccorum on racciiiium Mi/rtitlus. Young shoot of Bilberrj' 
with deformed branch bearing white conidi;il jiatches on its lower side ; also ii 
withered leaf. A, Conidial chains, and a portion enlarged. Ji, Shoot with an 
iipjjer healthy ripe berry and a lower munimified one. C, Peziza-cup develoi)ed 
from a Bclerotium. I>, .Ascosiwres ; the smaller incapable of gcnninatiuu, another 
germinating and giving off si)oridia. (.\fter Woronin.) 



tiieiu as food-material." " Finally, the germ-tubes penetrate 
between the elements of tlie outer rind already killed, and there 
develoj) to a stroma-like (iishitm of large-celled pseutlo- 
parenchyma from which the chains of (■niiiiHii emerge tlirougli 
the ruptured cuticle." 

(Sac'tanhj Jilso inciitiuiis ,Sr(. oreDplilln Sacc. mi Icavt's of Vacihiinm 

Sclerotinia oxycocci Wdr. The s(ler(ttiuiii disease of the 
true craiibeiiy {Viuruiium Oxi/cocciLs). The spores of this species 
are smaller than those of the ]irece(ling: each aseus cuntaiiis four 



260 



ASCOMYCETES. 



larger and four smaller spores, the latter appearing to be rudi- 
mentary and incapable of germination. 

Scl. baccarum Schroet.^ (Britain).- The sclerotium disease of 
the bilberry ( Vacc. 3^yrtillus). This varies from the other species 
in having round conidia incapable of germinating in water, in 
having more robust apothecial beakers, and in lacking rhizoids. 
The spores are similar in number and arrangement to the 
preceding species. 

Scl. megalospora "VVor. The sclerotium disease of the crow- 
berry {Empctrum nigrum). This species is distinguished by the 




Fio. 138. — Sclerotinia megalospora on Voxcinium vMginosum. Partiallj' withered 
leaf with a white conidial cushion on the mid rib. A, Conidial chains produced 
on a mycelium, resulting from an artificial culture of ascospores in plum-solution. 
B, Isolated conidium with remains of disjuiictors still attached. C, Twig with 
upper mummified berry. E, Ascospores ; one in its gelatinous envelope, the other 
giving off a germ-tube and sporidia. (After Woronin.) 



form of its conidia, and the manner of their germination ; in the 
form of the sclerotium, and the absence of primordia ; in the 
absence of rhizoids ; and, particularly, in having large ascospores 
almost similar to each other. 

The " white berries " of the Vacciniaceae are distinct from the 
mummified berries caused by Sclerotinia? 

Scl. aucupariae Ludw. The mummified fruits of Pyrus 
Aucuparia, resulting from this fungus, were first observed by 

^ Schroeter, Hedioigia, 1879 ; Woronin [loc. cit. ). 

- Sclerotia of this species have been found in Scotland by Professor Traill, 
^Magnus and Ascherson, Berichte d. deutsch. botan. Ges., 1889; also ZooL- 
botan. Ges., Vienna, 1891. 



8CLER0TINIA. 2G1 

Woronin ^ in Finland, and later by Ludwig in the Erz mountains. 
The ascocarp developed from the sclerotia has no rhizoids. The 
ascospores infect leaves, and there the conidia are produced. 

Scl. padi "Wor. Causes mummification of the fruits of 
Prunes PutJns. Woronin regards Monilia Linhartiana Sacc. as 
belonging to this Sderotinia. 

Woronin also considers the conidial form Monilia ciiurca 
as related to the mummified fruits of cherry. 

Ovularia nelans on Mespilus is prol)ably also a form of some Sderotinia. 

A Sderotinia occurring on Cotoneaster nigra protUues miunmification of 
the fruit, and forms conidia on tlie surface. 

Jfonilia friictigena of the apple, jjear, quince, plum, peach, etc., is in 
all likelihood a form of some Sderotinia, although the ascns-form is still 
unknown (see also " Fungi imperfect! "). 

Scl. betulae Wor. (U.S. America). This sclerotium of the 
bireh-t'ruit was discovered by and briefly described by Woronin 
in 1888. Xawaschin - has recently re-investigated it, and 
named it the " birch-catkin disease." It is found on the green 
catkins in June. The fruits containing sclerotia are obcordate 
in shape, instead of the normal elliptical form with both ends 
acute ; the wings are similar to those of healthy seeds. The 
sclerotium is composed of a very hard white pseudoparenchyma, 
which passes in the form of a horse-shoe round one side of the 
apex of the fruit (Fig. lo9). The outer layer is black and very 
firm. Sclerotia placed on moist sand produced ascocarps at the 
beginning of May. Development in the open also takes place 
about tliis time. In the birch forests near St. Petersburg this 
disease is common, and birch-catkins containing sclerotia may 
be found abundantly amongst fallen leaves about the month of 
May. From each sclerotium there are produced imc or iwn 
a.scocarps, with rliizoids and stalks of a length varying with 
the depth of dead leaves on tiie ground. The apotiieeia 
are at first funnel-shaped, liut later l)ecame saucer-shaped 
and l-4mni. limail, with a golden or lleshy colour. The asci 
contain fight spcjres which are forcil)ly ejacuhUiMl, and if a 
handful of damp birch leaf-moultl is thrown up into ilu- air 

'Woronin, Jii rirh/f <l. i/<iit.ic/i. Iio/dii. tiis., iSiM; iil.su Mini. (/> /'ardil. iin/'. 
•I. Mri. lit Sf. /'rteriililinj, IS'J.'j. Willi (i\i- platts. 

-' Niiwiiscliiii, Srtf.rot inia httidto, Wdt. Kiih.siiiii Itniohuro with four eoiouri'il 

pl.lt.s, IS'.Cf. 



262 



ASCOMYCETES. 



a cloud of spores so ejected may easily be seen. Infection 
takes place on the birch flowers. It is possible to promote 
germination in water and on moistened leaves, but the germ- 
tubes soon die. 

This disease, on account of the small size of the birch fruit 
and the tiny sclerotia, remained for a long time quite un- 
observed, yet it seems to be common everywhere ; in Paissia it 
has been found frequently, also in Germany, North America, 
and Japan. It possesses considerable economic importance, 
since diseased seeds are no longer capable of germination. 




\.:yyv-:^ 




Fig. 139. — Sclerotinia hetulae. a, Birch fruits with sclerotia, which have 
germinated and formed cup-hke apothecial discs ; rhizoids have developed on 
the stalks, h, Birch fruit, somewhat enlarged, with semilunar sclerotia. (After 
Nawaschin.) 



Hormoviyia hetulae Wtz. often occurs along with the above. 
It causes the production of thick spherical fruits with little or 
no wing. Sclerotinia aelnsta Karst. has also been found on 
birch leaves in Finland. 

Scl. alni Naw. Woronin found this first on catkins of 
Alnus ineana. Nawaschin has more recently investigated it.^ 

Scl. rhododendri Fischer.- This was first discovered by 
Fischer in 1891 in fruits of the Alpine-rose (Bhododendron 
fcrrugincum and R. hirsutum) in Switzerland. It has since 
been observed in various parts of Switzerland and the Tyrol. 

^Nawaschin, Berichte d. deutHcli. hofan. Ges., 1894; Maul, Hedwiqia, 1894, 
p. 213. With two plates. 

- E. Fischer, Naturforseh. Ges. Bern, 1891 ; also Berichte d. schiceiz. hotan. Ges., 
1894. With figures. 



SCLEKOTINIA. 263 

Fischer succeeded in obtaining stalked ascocarps from sclerotia 
of one and two years old. They resembled most closely those 
of Scl. vaccina, their stalk being provided with numerous rhiz- 
oids. The asci contain eight similar spores which germinate 
directly on ejaculation. They develop a mycelium and, later, 
chains of chlamydospores which separate by means of disjunctors. 
The little conidia found by Woronin on Vaccinium are never 
produced. The paraphyses are generally unbranched and corre- 
spond in length to the asci. 

The mummified fruits are ea.siest found after the healthy 
capsules have dehisced, then the diseased ones remain clo.sed. 
In winter the healthy capsules remain attached to the plant, 
the diseased fall off. Seeds of diseased capsules are completely 
overgrown by hyphae. 

Wahrlich ^ found sclerotia in capsules of Bhod. claliurirum 
from Siberia. They gave oft" a sclerotial ascocarp with a stalk 
devoid of rhizoids. The nuunmified fruits resemble closely those 
of Sd. rhudodcndri. 

Scl. heteroica Wor. et X;tw. = Scl. ledi Naw.- occurs on 
Lrduin piildsti' ill K'ussia and Fiiihiinl. It is very similar to 
*SV'/. rhododcndi'i, but is distinguished by the paraphyses being 
swollen and frequently forked at the end. In nutritive gelatine 
a copious mycelium is developed, and produces chains of ripe 
conidia with tiny disjunctors. Woronin fdund that the.se conidia 
are pmduccd only on Vaccinium iili(ji/iosirm, never on Lcduin : 
but the conidia so formed can successfully infect the ovary of 
Liduia. We iuive here the first known case of heteroecism 
(tiitsjilf tlif rii'diiicae. 

Scl. sclerotiorum Lii).-' (Uritain and I'.S. America). Thi; 
.sclerotia of this i'ungus are found in many various jijauts. 
They fall to the gr(jund with the dead iilanls, jiibernate under 
snow, and on the arrival of warmer weather in spring give 
rise to several stalked a])otheeia. The ascospores are ejaculated 
from the asci, germinate, and produce a parasitic mycelium, 
described thus In' I )e lUiry : "The ripe spores of J'<:i:<( 
svlirolioriiin jiroduee germ-tultes on any moist subsiratuin. 

^liirirhl, ,1. ,/,,1/xrh. hulaii. (!<»., KSll-_'. 

- XaWiiHcliiii, JiirirhU il. dinttrh. ho/an. (!>»., 1S94, p. 117. 

^ Href«-lil, Sr/tiiniiu/f>i/-i , IV. ainl x. ; Du Hiiiy, Moi/iho/t/iji/ and Jiio/oijy oj the 
Fniii/i ; anil Jio/dii. /'itiiinj, ISSIi. 



264 ASCOMYCETES. 

These develop to strong mycelial threads if they reach any 
source of nutriment, such as disorganized bodies and particularly 
dead plants. On any other substratum the germ-tubes never 
pass beyond a rudimentary stage. The germ-tubes developed 
in water cannot make their way into living plants. If, however, 
grown in suitable nutriment, the mycelial threads are smaller 
and capable of penetrating as parasites into suitable hosts. This 
they are able to do because they give off a fluid which enters 
into and kills living plants. The dead parts of the plants 
serve as nutriment to the fungus, which makes its way into 
the tissues and causes death of cells in direct contact or im- 
mediate neighbourhood. The deadly fluid separated by the 
fungus contains, as an essential constituent, an enzyme soluble 
in acid solutions and capable of dissolving the cell-walls ; also 
a number of imperfectly known organic and inorganic acids 
and salts, amongst which oxalates can certainly be proved. 
The mycelium generally penetrates parts covered only by cuticle 
or a thin periderm. It does so by hyphal branches which grow 
into the air till they reach some suitable host ; then, stimulated 
by the pressure, they give off characteristic organs of attachment, 
which secrete a cell-killing fluid and cause disorganization of 
the place attacked ; they derive nourishment from the products, 
and give off branches which penetrate into the plant." 

Conidia capable of germination are never produced, though 
rarely tiny spermatia or conidia incapable of germination are 
abjointed from the mycelium. 

A Botri/tis-stnge is certainly never present in the life of 
this species. 

Scl. sclerotiorum is one of the worst enemies of cultivated plants. 
De Bary observed total or partial death resulting from it to 
the following plants : Phascolus vulgaris, Petunia nydaginiflora 
and P. violaceac, Solanum tuherosum, Zinnia elcgans, Helianthus 
tuherosus, and Daucus Carota. It has also been found on species 
of Brassica, Beta, Cichormm, Dahlia, Topinamhur, etc., and on 
seedlings of numerous other dicotyledons. It is thus evident 
that many and varied plants, belonging to widely removed 
families, may serve as hosts ; on the other hand the fungus 
avoids certain plants, and is known to injure species in one 
locality, which it avoids in another. 

De Bary regards a destructive canker on hemp in Eussia 



SCLEROTINIA. 205 

(Feziza Kavffmaniana Tichoiu.)^ as related to, or identical with 
Scl. sclerotiorum. Behrens, however, is inclined to ascribe it 
to Scl. Fv.cJcelin.na, which has occasionally a Botn/tis-staoe. This 
hemp disease has also been found in Alsace.- 

Humphrey ^ rej^'ards this species as the cause of a disease 
of indoor cucumbers ; he ascribes a Botri/tis-stnge to it. 

Scl. sclerotiovuvi is best known by the conical funnel-shaped 
depression in the hymenial disc, not present in other species. 

Sclerotinia trifoliorum Eriks ^ (U.S. America).^ Clover 
is not attacked by ihe Sclerotinia last considered, but falls an 
easy prey to this species, which again derives but scanty nourish- 
ment from such food as fresh carrots. *SV/. trifoliomna is 
observed wild only on species of clover, and is there fairly 
common ; many other plants, however, have been artiticially 
infected by it. Host-plants are attacked through their L;reen 
foliage, which very soon becomes brown and shrivels up. If 
the atmosphere be sufticiently moist, the mycelium emerges 
on the exterior and spreads to neighbouring organs or plants. 
Sclerotia are not often formed superficially as with Scl. 
sclerotiorum, because the mycelium lives principally inside 
the )tlant tissues. This mycelium resembles that of >SV/. 
sclerotiorum in its peculiar property, that successful infection 
only follows if the fungus has lived for a time saproithytieally ; 
on this account direct infection Ity spores is harndess. In tlie 
secretion of an enzyme and of o.xalic acid, and in the manner 
in wliich it destroys the tissues of its host-itlant, this species 
behaves like Scl. sclerotianim just described. Il is distinguished 
by its larger ascospores, and the absence of a central funnel- 
shaped depression in the hynieniuni. Sjiores germinated in water 
produce numerous bodies (so-called spennalia) which distinguisli 
the sjjecies from Scl. Furhiiana where this does not lake iila( e. 

llostrup'^ found in Denmark that Mnliciujo lupulina sullered 

' 'I'iclioinirotr, linll. nor. unt. dt Mosraii, IS(!H. 

- lielireiiH, " Ueher das Auftreteii d. Haiifkieljsfs iiii Klsiuss." Zrilschri/l /. 
/'Jlall'.nlh■'tllli■h^l(^ll, 1S91, p. 20S ; " Trocki'iio u. iiasso Kaule d. Tiilniks," ii/'iii, 
IHm, ]>. H'2. 

■' Hiiiiiphiey, -I;/'/''. >x/n r. .slntlnii Mats., lJ>'.l'J, |ip. "J 1 J "J- 4 . 

* Kiilin, " Die Skli rot it'll kraiiklnMlfii d. Kleew. " Hi-dwiijiu, 187'^. 
Keliiii., EnhrirkiliiiiiiMiii Hih. niiixtf. Klii- ziTxIiireuili'n Pit-fn. 

* MiiMMt-e (/yriVM/( FiiiKjHM-jloia, iv., Isil.'ii. "'I'litTf is no cvidnnf of this spccii-s 
htiviiig occurred in liiituiii." 

"|{r>f*tnip, Ti'iiKkri/l thr l,'iiid-,kiiii(,ni'f , IS'.tO. 



266 ASCOMYCETES. 

most from this fungus ; red clover was less affected, though 
the disease often had its origin in that species ; while white 
clover was least often attacked. He recommends keeping out 
Medicago from clover mixtures, and the addition of a large 
proportion of grass-seeds. Fields badly affected should be 
kept out of clover-cultivation for several years. English and 
French white clovers he found to be very sensitive, but distri- 
bution of the fungus did not take place by means of seed. 

Scl. tuberosa (Hedw.) (Britain and U.S. America). This 
on the rhizomes of Anemone nemorosa causes formation of 
sclerotia larger than filbert-nuts. The ascospores on germination 
produce groups of flask-shaped processes from which are given 
off chains of spherical conidia incapable of germination. Certain 
pycnidia which appear on the anemone-plants or on the sclerotia 
belong to a parasite {Pycnis sclerotivora Brefeld). 

Scl. bulborum Wakk.^ (Britain). Wakker observed this form 
on hyacinth, onion, etc. It is very similar to Sel. trifoliorum, 
but the hyacinth-fungus will not infect clover, and vice versa. 
The leaves attacked become rotten and the plants die.^ 

Eriksson describes, from Werniland (Sweden), a destructive appearance of 
bulb-rot due to sclerotia, which he attributed to Scl. Fuckeliana De Bary. 

Scl. candolleana Lev. on oak-leaves. 

Apijcnclio'. 

Sclerotia of Unknown Affinity. 

Scl. oryzae Catt. llice plants {Onjzec -mtiva) are often 
attacked by this SderoHum, and a disease called " Brusone " 
produced. The sclerotia are found during June in the sheaths 
and stems. The symptoms are blackening at the base of plants 
and withering of upper parts. 

Scl. rhizoides Auersw. occurs on living plants of Pludciris 
arundinacea, and Grdamarjrostis ; also on dead leaves of Dactylis 
gloinerata. 

Scl. rhinanthi ^Nlagn.^ forms sclerotia on the roots and root- 

1 Wakker, Allgem. Vereenhj. voor BloemhoUencultur, 1883-84; also Botan. 
Gentralblatt, xxix. , 1887. 

-G. Massee (Gardener's Chronicle, Vol. xvi., 1894) gives description and 
figures. 

^ Verhand. d. hotan. Ver. d. Pror. Brandenbtir;/, xxxv. 1894. 




SCLEROTIA OF UNKNOWN AFFINITY. 2b i 

neck of living Bliiaantkus minor: these bodies begin their 

development in the canibiuin and bark, which they kill ; attt-r- 
wards the wood itself niav be attacked. 



Sclerotinia with Botrytis-conidia.' 

Scl. Fuckeliana i'e Hury. This Schrotinid [<, distinguished 
from all laeceding ones by its passing through a Botri/tis- 
conidia stage {Botrytis cinena). If conidia are sown out on 
plum-juice gelatine, there appear within fourteen to twenty-one 
days round groups of sclerotia, which soon 
give rise to conidia. From such artificially- 
reared sclerotia I have never succeeded in 
getting the Peziza-ir\\\t, so easily cultivated 
from sclerotia gathered in the open-air ((.//. 
from vine leaves)." Thus the actual proof 
that Sd. Fti.cl.rliand. and Botrytis cinerca are /vcWwHn^'i^pe-rot'o" 
stages in the life of the same fungus is not scierotl!r' ^"''"Tubeuf 
reached by this experiment.^ The two forms '^''''^ 
are, however, very frequently met together. 

The sclerotia of Sd. Fiakclvaia are produced in the mesophyll 
of the leaves, also in the parenchyma and epitlermis of the 
host-plants, but never in the wood. Peziza-hmts with tlat 
apothecia are produced from them. Sclerotia are found in vine 
leaves and over-ripe grapes (Fig. 140), especially of the liie.sling, 
Orleans, and Sylvaner varieties.^ Other plants and fruits may 
also be attacked. Di.sea.sed parts become brown from tlie 
effects, of the parasitic mycelium, and die oH'. The mycelium 
can only live parasitic after it has been strengthened by a pre- 
vious saprophytic existence. Ascospores are thus unabli* to 
etl'ect flirect infection. The />(*^/7///.s-conidia seem, however, 
capal)le of directly infecting a host-plant, at least I have always 
succ«'eded in infecting Conifers successfully with the cnnidial 
form JJn/ri/fis JJniiylirsii. 

'See n\m> liohytin aiiioiig.st the " Fiini;! iinpi-rffcti." 

-Brefeld, Heft iv., p. \'2{), ami X., |). .Sl."> ; TiilMuf, /iritrdije z. KmiifiiiHs il. 
J!ft itinkraiik/it ilfii, 1 SHS. 

■"Zfipf. (fJic Pih.t-, ]). 74.) .stiiti-H tliiil /'« ■.(■.^( fiuits may l»i' ri'iircil ficiiii tlu-se 
Hclerotia after tliey have rewted a year. 

^Miillir-'rhuigau, "Die K.lelfanle «1. TiaulHii." /.luulirirth. Jnhrl.itr/,, 1SS8 
iliif. in /li,/fiii. Ciutni/h/n/f, xxxv., IShS, p. <I4). 



268 



ASCOMYCETES. 



Epidemics of great magnitude have been ascribed to attacks 
by the Botrijtis-iornis of this Sderotinia. Thus on lilies in 
England,^ on yellow gentian,- on male flowers of Conifers, and 
on the twigs of Conifers and other plants. This is especially 
the case in houses under glass, where the fungus, favoured by 
the moist atmosphere, lives as a saprophyte on dead plant-remains, 
and multiplies till it becomes strong enough to act as a 
parasite. It is, however, quite possible that conidial forms of 
other sclerotia {e.g. Sd. sdcrofiori(vi) may be confounded with 
this species. 








Fig. 141. — Botnjtis cinerea (Set. Fuckeliana). Branch of Pro.nus triloba with two 
diseased shoots, withered and dead. (v. Tubeiif phot.) 

The presence of Botrytis and allied forms on the vine is the 
cause of a disease of great economic importance, because severe 
loss may be incurred through rotting of the grapes and the 
injurious after-effects on the "most." 

A decay of the potato-plant is said to be caused by sclerotia 
formed inside the stems, and also by a Botrytis? Smith* has 
figured similar sclerotia, which he ascribes to Peziza posticma 
Berk, and Wil. 

iH. M. Ward, AwialH of Botany, 18SS. 
^ Kissling, Hejho'njia, 1889. 

•'' Ritzema-Bos., ^TeiV-scA. yi PJlanzenkranklititen, 1894; O. Kirchner, Wurtemhurg. 
■ Wochtnhlaft f. Landwirth., 1893. 

■* Worthington G. Smith, /)(seas<-s of Field and (kcrdtn Crops. London, 1884. 



SCI.EROTINIA WITH ISOTRYTIS-COXIDIA. 



269 



Sclerotia, along with ^'o/'/vy/'/.s-conidia, have been found fre- 
quently on diseased geraniums. 

During the summer of 1894 a withering of twigs of Pruims 
triloba occurred in several gardens at Munich (Fig. 141). A 
mycelium was found in the bark, leaf-petioles, and young 
ovaries, while Botrytis-Qon\^\\^ were 
developed on the dead parts. 
AVith these I successfully infected 
young needles and twigs of spruce. 
.Sclerotia were also formed on plum- 
gelatine in fourteen days. The 
parasite in this case had killed old 
twigs of Pruaus, and also infected 
twigs of Conifers. 

Botrytis Doug-lasii is a parasite 
which 1 siudit'd soiue time ago on 
account of its presence along with 
a disease on the Douglas tir {Pscu- 
dotsncja Domjlasii)} I have since 
had reason to believe that it is 
allied to some form of sclerotium 
like that just considered, and my 
view is supported by Behrens." 
The di.sease as seen in various 
parts of Germany is characterized 
by withering, curling-up, and deatli 
of young shoots towards the sum- 
mits of young seedlings, and on tlie 
lower twigs of older trees up to 
about five feet above the ground. 
In autumn, Itlack sclerotia about 
the size of pin heads, break through 
the ei)idermis under the old bud- 
scales, at the base of dead shoots, 
and on the needles. In addition 
tangled hypliae are also formed, 
in a intjist chamber, tufts of erect conidiophores arise, and 
branch, forming numerous whorls of conidiophores, from wliich 

'v. Tul)fiif, Ihitniiif -.. KeiiHlninH d. lidumkranklitilfu, lUiliii, 18S8. 
'-■ Uolinim, Z'it'irh. /: l'fUonuikrankli>ilni, 189.">. 




Fici. \i2..— Botrytis Dou<jUi»ii on the 
DoU({lftH Fir. Tho young shoot-' and 
apex of lust year's .shout aro tlead. 
(After TulKMif.) 



to these, .smaller massi's of 
When sclerotia are placed 



270 ASCOMYCETES. 

oval hyaline conidia are abjointed. These germinate at 
once in water, and infect young developing shoots or needles 
of Douglas fir, silver fir, spruce, and larch. Death of these 
ensues in a few days, and finally the whole plant is killed. 
On the dead needles a copious development of Botrytis takes 
place, and the conidia being easily detached, spread the 
disease in damp localities. The mycelium and conidiophores 
are very sensitive to drought. The sclerotia serve to carry 
the fungus over winter, and may be found in autumn and 
winter. 

I have found Jv.nvperis communis with its young shoots dead, 
and sclerotia similar to the above on the needles. 

Whether Scleroti/na Kerneri Wettst. found on needles of Abies pectinata 
is parasitic or not, I do not know. 

Scl. galanthi Ludw.^ Ludwig observed this disease on 
snowdrops. In place of the flower a shapeless mass was pro- 
duced, completely covered with conidiophores of Botrytis. The 
sclerotia develop inside the tuber. 

Scl. pseudotuberosa (liehm). {Sd. Batschiana Zopf or Ciboria 
psevdotuh-rosa liehm) (Britain). The cotyledons of acorns are 
sometimes found replaced by a firm sclerotium, from which a 
peziza-fruit {Cihoina) is produced. Nothing is known in regard 
to mode of infection or the parasitism of this species. 

EU-PEZIZEAE. 

The apothecia, at first closed, open out to form saucer- 
shaped or cup-like discs, with a margin. The discs have 
usually a thick hypothecium ; they are fleshy or waxy in 
texture, and are often brightly coloured. 

Dasyscypha. 

The waxy or membranous ascocarps are sessile or shortly 
stalked, and beset on the outer surface and margin with hairs 
of various colours. The asci dehisce by a round apical opening. 
The spores are ellipsoidal or spindle-shaped, unicellular, and 
hyaline. The paraphyses are thread-like. Most of the forms 
are saprophytic on dead plants ; the following species alone 
is known to be parasitic. 

^ Liulwig, Lehrhuch d, nieihren Kryi)togamen. 



DASYSCYPHA. 



L'71 



Dasyscypha (Peziza) Willkommii. Harti^.^ The Luieh Canker 
(Britain ami I'.S. America). Kveiywhere in the mountains, the 
home of tlie hiich, one finds, on young I tranches and old stems, 
depressed canker-spots, on which the sporocarps of Dasyfici/iilui 
Willkommii are developed. Young twigs, when attacked, are 
already conspicuous in 'luly and August by their pale and 
withered needles, and on them small 
canker-spots will be found ; these rapidly 
enlarge so that on older stems they may 
reach very great dimensions. Hartig easily 
succeeded in producing canker-spots on 
healthy trees by artificial infection. 

If canker-spots are examined soon after 
the death of the bark, the stromata will 
be fountl as yellowish -white pustules. 
Conidia are produced either on the free 
surface or in the internal cavities of a 
stroma ; they are tiny unicellular hyaline 
bodies, produced from little conidiophores. 
Hartig never succeeded in getting these 
spores to germinate. If the atmosphere 
be moist enough the apothecia make their 
appearance later on the same places ; they 
are externally yellow, and internally orange- 
coloured. The apothecial disc carries long 
thread-like paraphyses and cylindrical asci 
with rounded apices (Fig. 14o). The asco- 
spores are oval, unicellular, and hyaline, 
give off one or two germ-tubes which are unable to penetrate 
the periderm of a host-plant, and only find entranci' through 
wounded places. "Wounds are very common on larch as the 
result of hail, or injury to twigs l>y snow or ice, or destruction of 
needles by insects. For example, the Larch-moth {Colcopliinn 
lariccUa) is well known to cause less damage on the mountains 
than in the lower regions, and in the same degree Ihifijixci/phK is 
least injurious to mountain forests. 

The mycelium is sejilale and murh braneheil ; it spreads 
ehii-lly throu'^h the soft bast, especially in the sieve-lubes and 




Fig. 143. — Ikisiiieyphtt 
M'iUkonvnii. Three nsci inul 
two piinipliyses isolated 
from an apotheciuni. (After 
R. Hartitr.) 



Thev "jcrnanate and 



' K. Uaiti^', I'liti isiir/i, aii> il. /oi-'i/liDtiiii. Iiiitiltil Mihirhm, i., ISSO. .M. Will 
koiiiiM, MiLrui. Fiiiiili til s ]i'ii/,l,H, II.. ls(is. 



272 ASCOMYCETES. 

intercellular spaces, but it may also penetrate the wood as far 
as the pith. The fungus only spreads during autumn and 
winter, never during summer, the vegetative period of the 
larch. The attacked tissues of the bark turn brown and shrivel 
up, causing the depressed canker-spots. Healthy parts continue 
their growth normally, and are frequently cut off from diseased 
areas by formation of layers of secondary cork ; this isolation 
is, however, rarely effective, since fresh invasions of mycelium 
from the wood into the bast take place annually, and thereby 
the canker-spots keep enlarging for an indefinite time. 

The fungus develops reproductive organs only in damp marshy 
situations. On this account spore- formation is less frequent on 
mountainous slopes than in moist valleys and ravines. The 
larch, on its first introduction into the low- lying parts of Germany, 
Denmark, and England, was much cultivated as a pure forest in 
close damp localities, and with great success ; but now this parasite 
has followed its host from the mountains and causes ever 
increasing damage. 

As preventive measures may be recommended : larches in 
low-lying districts should be grown in open, airy situations, and 
never massed together nor placed in the neighbourhood of diseased 
larches. 

Lachnella. 

The reproductive organs are similar to Dasyscjipha, but the 
apothecia are firmer and generally have no stalk ; the spores as 
a rule become two-celled at maturity. 

Lachnella pini Brunch.^ occurs in Norway on twigs of Pinus 
sylvest7'is, as a parasite which quickly kills young plants and twigs. 
It is rare on old plants. The apothecia resemble those of D. 
Willkonimii, but are larger, externally brown, and covered with 
brown hairs and scales. The disc is reddish-yellow with a whitish 
margin. The asci measure about lOO^i by 9/a, and contain 
colourless unicellular spores about 20^t long. 

Rhizina." 

This genus contains the single species Rhizina undulata 

' BruiKjliorst, Nocjle norske skorsygdomme, Bergens Mas., 1892. 

-Rhizina has a position somewhere between the Pezizeae and the Helvelleae. 
Saccardo places the genus under Pezizeae, while Schroeter makes for it the 
special group of Rhizinarei, included under his Helvellinti. 



RHIZINA. 2<:5 

Fr. {lUi. iajiata, Schaetf.). liout fuuLjus, ur Ifiii^f-disease.^ This 
fungus is found as a saprophyte on the earth, especially where 
forest fires have occurred ; also as a parasite on indigenous and 
exotic conifers. As such it has been observed in nurseries in 
various parts of Germany, and in woods of Pin us Pinaster in 
France. The fungus itself is known in 1 Britain, though not as 
a parasite. 




VUi. 144. — Sporophores of JViizina undulata. 
<!, Uppor surface ; b, lower surface ; c, small 
sporophorct. (After Harti({.) 



\hl 



Fiii. U.'j.— Section of hyiiiciuuni. a. Parii- 
physes; ^, secrctiiiK-tubcs; c. usci, each with 
eight spores. (After llarti«.) 



rh(! disease extends t'rolu a clmiIic aiul altaeks one plaiU 
after another, eansing tlieiii to lose their needle.s and ilie. 
The s])Oio]tliores are large (ji to 2 inches), chestniit-biown, 
flattened or undulating structures, whirli sit din-rlly on ihe 
niyceliuiu, without a stalk. On the upjier surface is the 
asecjgt'uoiiH layer wliich, when moist, is peculiarly sticky and 

' |{. H:irtig. Fi)rMf/-iiii/uriris-i,ii. Zi itxrhrifi., ISII'J, p. ."i'.»l ; I'lillioux, ('uiiipt. 
mill. ,le la Soc. ittt A<jnr., ISSO. 



274 



ASCOMYC'ETES. 



glutinous ; it consists of small eiglit-spored asci over which 
project septate paraphyses, and also non-septate paraphyse-like 
structures which discharge a brown secretion. The ascospores are 
unicellular, hyaline, and canoe-shaped ; on germination they give 
off a germ-tube which immediately develops into a septate 
mycelium. The mycelium is found in the intercellular spaces 
of the rind-parencliyma, but in the bast it grows both inside the 
cells and between them, so that the sieve-tubes are often completely 





Fig. 14(3. — Ront-system of a Silver Fir 
overgrown and killed by the mycelium of 
Rhizina undulata. (After Hartig.) 



Pig. 147. — Ascospores of Rhizina. a, As 
taken from the ascus ; b, 24 hours after 
sowing ; c, 48 hours after sowing ; d, the 
spore of c enlarged. (After Hartig.) 



filled up. Masses of fungoid pseudoparenchyma are frequently 
formed between the dead and diseased tissues. Strands of the 
nature of Rhizodonia emerge from the diseased roots, many 
of them carrying thread-like processes, at the extremity of 
which an oil-drop is secreted and escapes on rupture of the apex. 

According to Hartig, very tiny conidia are abjointed from 
the mycelium. 

De la Boulage^ and Prillieux have both come to the conclusion 
that "la maladie du rond " of Finns sylvestris and P. maritima 
is the same disease as the " ring-disease " caused by Rhizina. 

^ BiiH. da la soc. r/e.s Afjric. de France, 1880. 



THK HKLVELLACKAK. 27 '> 

Appindu. 

The Helvellaceae. 

This family is well kiiuwu, suiue as poisonous, others a^^ 
edible fungi (morel, etc.), and a few are suspected of being para- 
sites. The ascogenous layer occupies the upper surface of the 
sporophores, which grow on the earth and assume many various 
forms. As a rule they are erect and flesliy, and more or less 
lobed, wrinkled, or folded. 



USTILAGINEAE. 

The Ustilagiueat' or Smut-fungi are distinguished by their 
dark-coloured or black chlamydospores, which, on germination, 
produce some form of promyceliuni capable of giving rise to 
an indefinite number of conidia or sporidia.^ The chlamydospores 
themselves are produced in large numbers from a mycelium, 
and serve as resting-spores to carry the fungus through the 
winter, being often, in fact, the only part which persists. An 
endogenous formation of spores in sporangia as in the lower 
fungi, or in asci as in tlie Ascomycetes, does not occur in 
the Ustilagineae, Uredineae, or Basidiomycetes. 

The resting-spores of the Ustilagineae contain only one 
nucleus, the result of copulation of two nuclei ; their formation 
thus marks the end of one generation, and their germinatitm 
the beginning of a new. In the case of the Uredineae, JJasidio- 
mycetes, and Ascomycetes, the beginning of the new generation 
is indicated by the germination of the teleutospore, tiu' formation 
of basidiospores on the basidiuni, aiul the germination of tlie 
ascospore respectively. 

All the Ustilagineae are parasitic on higher plants, the 
mycelium growing intercellularly and nourished by means of 
haustoria sunk into the host-cells. 'I'he uiycelium itself causes 
neithei- disease noi- delormalion of plants, and it is only when 

' liiifuld ifgarilH the proniyct.'liuiii of llir L'-Hlilaniiitac not, like De Han , as 
II iiiyctliiil Htruetiire, Imt as a conidiophnre or liasidial .Htnietuie. In aeeonlance 
with tills view he has foiiinleil his intei iiieiliate jjioiij), the Hi-niihasiilii eoi re 
Hl>oinlin^.' to the U»tilii^,'iiieae. Mrefehl then sulxliviiies this K><>1'1' '"'" •") l-'stila- 
),'ineae I f'xii/iK/o, Sjihrtr, /olfn rd, Sil,i:i,ii' ll(i, 'J'iil!//'i'</'on'iini), which a.s a rule 
have a .stptate proniyieliuni ; ami (l>) Tilletieae ( 7'i//< tin, Kiilyloiiia, Mifnnotntiiiinii, 
Sihro't' rill, 7'li'i(i/,/toi(t, Sunn/iniiiDii), with hon-Heptate proniycelia. (Sc/iimniel 
]>i/y, M.ft v., lss;{, ami Heft m., Is'.Ci.) 



276 USTILAGINEAE. 

the resting-spores are developed that deformation occurs. These 
spores arise by intercalary growth in the mycelium, which is 
generally completely used up in their formation ; they are 
produced in large numbers, and scattered after decay of the 
tissues enclosing them. 

As a result of the germination of the resting-spores, there 
is produced either a mycelium capable of immediate infection, 
or a promycelium from which conidia ^ are abjointed. In the 
latter case, conidia are generally formed in succession, and 
continue to be given off from the promycelium for a considerable 
time. They either give out a germ-tube capable of infecting a 
new host, or give rise to further conidia. The latter process 
is most frequently observed in artificial nutritive solutions, 
where the conidia continue to sprout in a yeast-like manner 
till nourishment is exhausted, when they germinate and form 
mycelial filaments. In the host-plant, chlamydospores alone 
are developed, conidia exceptionally {Tuburcinia and Enty- 
loTYia). 

The Ustilagineae are very dangerous and injurious enemies 
of cultivated plants, especially to the various cereal crops. The 
species are fairly easy to identify, because each is, as a rule, 
confined to one or a few species of host. The smut-fungi are 
best combated by sterilizing the seed of suspected cereals in 
a copper sulphate solution or in hot water shortly before 
sowing out ; (see General Part, chap, vi.) In this way any 
adherent smut-spores are killed, and where this preventive 
measure is regularly carried out, disease is less common and 
its effects considerably minimized. 

The Ustilagineae include the following genera : Ustilago, 
Sphacelothcca, Schizonella, Tolyposporium, Tillctia, Entyloma, 
Melanotaenium, Urocystis, Tuburcinia, Daossansia, Schroetcria, 
Tlieca'pliora, Sorosporiwiii, Graphiola, Schinzia, Tubercularia. 

Ustilago. 

The vegetative mycelium makes its way through the tissues 
of the host-plant without causing any deformation. The spores 
are developed in certain parts of the host, and form a much- 
branched, compact, sporogenous mycelium, with membranes 

^ ' Conidia ' = the sporidia of De Bary. 



USTILAGO. 277 

which at first swell up in a gelatinous manner. Spores are 
formed inside the ultimate ramifications of the mycelium, and 
as they reach maturity, the membrane loses its gelatinous 
character, the cells break up, and the spores are set free ; they 
are dispersed as a dry dusty powder after rupture of the tissues 




L- 

Flfj. 14S.— r»<i7af/o uiapilii. The lieaii liiis 1k.x'1i exixisetl U> view liy diHscctiiiK 
iiway the enclosiii^f leaves; if is ]<L-nvt tiwanis tlic iipux )iv Miiiiit-lHiilN. 
(V. Tubcuf |.liot.) 



of the host enclosing tlnni. The sporus germinate, giving rise 
to a promycelium (basidium), which becomes divided uji bv 
means of cross-septa into several ctdls, from each of which 
conidia are laterally abjointed. TJiese conidia s])roul yeast- 
like, and give oil' new cuiiidi;!, or tln'y proihict' a ni\eelinm ; 



278 



USTILAGINEAE. 



the former is the case when nutrition is abundant, as when 
under artificial ' cultivation, the latter under less favourable 
nutrition ; in very unsuitable conditions, the constituent cells 




Fi<;. 149. — Ustilago mat/dis. Diseased Maize-lieuds after removal of enclosing 
leaves. The heads are beset with smut-boils of all sizes, some ruptured, others 
still unbroken, (v. Tiibeuf phot.) 

of the promycelium may each develop directly into hyphae 
capable of infecting a new host. 



USTILAIJO. 



y 



Ustilago maydis (D-*-'-)^ (IJrituin and U.S. Auieiieu).- Tliis 
smut of Z'li Mai^ produces large and conspicuous defonnations 
on leaves, leaf-sheaths, stems, roots, and all parts of the male and 
female dowers. These are whitish, 
gall-like swellings and blisters, 
containing a mass of gelatinous 
mycelium, from which spores are 
produced. The swellings may 
attain to the size of a fist, or 
even larger. The spores appear 
at first as dark olive-green 
masses seen through the lighter- 
green outer tissues of the host- 
plant. AVhen mature the spore 
masses cause rupture of the 
enclosing host-tissues, and escape 
as a dusty powder. The spores 
are dark-brown in colour, irregu- 
larly spherical in shape, covered 
with delicate spines, and measure 
9-1 2u in diameter. They re- 
main capable of germination for 
many years. 

On being sown from the host- 
plant directly into water, very 
few spores germinate at once, 
yet if sown in the following 
spring they readily do so. In a 
nutritive .solution {i.y. plum-juice 
gelatine) an abundant germina- 
tion may Ije obtained at any 
time. A delicate hyaline hyi)ha 
is given out first, and after be- 
coming divided up by several cross-septa, it proceeds to abjciint 
conidia from various i)laces. The conidia sprout in the gehiliin' 




Fl<i. 150. — Uililafio mai/iU* in lifml 
Miiizo. (v. Tiibcuf phot.) 



' Ainericaii Litcnituro : U.S. I)>i>t. of AijilriiZ/iin //./'<. ;V, ISSil, p. .•{S(i, witli 
tluHcriiition ami recoinineniliitioiis a.s ti) tieatmcnt. Alsn Oliio .ti/rlr. Expi-i: Stat, 
linltitin. Vol. III., p. -271, 1>S'J0. 

-The principal iiiithoriticH for tliu ocourrem-f of the L'Htila>;iiUNii' in Hritain 
unrl the Uuiti-il Slate.H are Plowright {/iriti.sh Ustiliniinnii , 1SS!H, ami Fallow 
and Seymour i //oMt-imlfX of Fmi'ji of U.S. .\in-iir,t, IS'.ll). (Kilit.) 



280 



USTILAGINEAK. 



in a yeast-like manner, but on exhaustion of the nutritive 
materials, the primary conidia, and even the constituent cells 
of the promycelium, give off germ-tubes. Conidia are never 
found on the maize-plant itself, but Brefeld's investigations 
have demonstrated their production on dung-cultures, so that 
conidia may possibly be produced on manure-heaps or manured 
soil, and young plants be infected by them. Brefeld has, 
by means of germinating conidia, successfully infected maize- 





FiG. I.jI. — Ustilago maydis. JIaize-head 
completely malformed into smut-boils, which 
have not yet ruptured, (v. Tubeuf phot.) 



Fir. l52.~Ustilago jucufdis. Smut-boils on 
stem and leaf of a Maize-plant, (v. Tubeuf 
phot.) 



seedlings as well as growing points and other young parts of 
older plants. 

Infection may take place on any immature part of the 
host. The mycelium does not grow through the whole plant, 
but only inhabits a part in the vicinity of the place infected. 
The heads are most frequently attacked, with the result that 
the grain fails to reach maturity, or is destroyed during the 
formation of fungus-spores. 

Owing to the danger of infection, grain mixed with smut- 
spores should never be used for sowing ; nor can such be 
safely used for feeding cattle on account of its injurious effects 
on them. 



USTILAGU. 281 

Knowles/ Cugini,- and Wakker^ have investitjated the 
anatomical chanj^^es produced In' this t'unLjus. The latter 
investigator found that the xylem-elements with unli^nified 
walls remain incompletely developed, and have a peculiarly 
twisted course ; that normal sieve-tubes are absent ; that tlie 
cells of parenchyma undergo secondary division, and give rise 
to a new tissue provided with little fibrovascular bundles, and 
rich in starch-contents, in other words, a nutritive tissue to be 
used up in the spore-formation of the smut. 

The disease may be found wherever maize is cultivated, 
and often causes a very serious diminution in the harvest. 
It may be combated by early removal and destruction of the 
smut-galls. As a preventive measure, the treatment of seed-corn 
with copper sulphate solution * is recommended. The avoidance 
of fresh manure is also advisable, since conidia capable of germi- 
nation may be lodged in it. 

The following are the results of an experiment carried out 
at my instigation by Professor Wollny in liis experimental 
plots at Munich. Three plots were selected distant from each 
other about 70 metres. On 2nd ^lay, 1893, these were marked 
out in rows 40 centimetres apart, in which maize was sown at 
intervals of 50 cm. The grain was previously mixed with 
smut-spores obtained from the Tyrol in autuuni, 1892. riot 
No. 1 was left without manure, Xu. 2 was treated witli old, 
Xo. 3 with fresh cow-manure. Maize had never been grown 
in the vicinity, so that no infection could result from external 
sources. Tiie results were : 















Smutted. 






N 


Ullllll 


1 of I'lant.-. 


Alisol 




Per cent 


Pint No. 


1, inimamired, 

•2, 1)1(1 co\v-ui;imiii-, - 




- 


1 1^ 


(1 




(1 




:5, iHW L-nw-inamuf, - 




- 


1:?:^ 


1 1 




7t; 



Ustilago Schweinitzii 'I'ul. fiom ( 'aiolina l'.S..\. is jui.liaMy idciitiral 
with f'st. iinii/i/is. 

Ust. Fischeri Pass.' This smut, ohserved in uppci lialy, 

' KiiowlcH, K. .1., Aimr. Juitnia/ o/' Mi/co/in/i/, Xdl. iv., Iss'.l. 
- Cuj^iiii, " II ciirbone dol graiKj tun-o," Jiu//. drll. slat. Aijrnr. i/i MdiI'Iki, 1s<i|. 
nVakker, J'riwjHhiim's Jahrhiirh, Hd. '24, ISII'J. 

••See "(ieneral I'art," chup. vi., and also '• \'fij;leicliiii<lc I'litt r.Mii limimn 
111). Flugbrundiirten." V. Htrzherg in Zoji/'s /iiititujtn, \S\t.'). 
' I'uHHiTini, Jiisi'm holaii. .Jdlirlnir/i, iSS'.t, ]i. 1_'.'!. 



282 USTILAGINEAE. 

attacks the axis of the maize-heads. Its spores are spherical 
with slightly granular coats, and measure only 4-6 ju. in diameter. 
It causes damage through shrivelling up of the grain. 

Ust. Reiliana Klihn. This smut frequents Sorghum halejoimse 
and >S'. ruhjare (Durra or Indian millet) ; also maize in various 
parts of Europe and America,^ as well as in Egypt and India. 
It is called " Haniari " in the Arabic language. 

Kiihn ^ thus describes it : " This species causes the ears of 
Durra to become large smut-galls of roundish or ovoid shape, 
with a height of 60-95 m.m. and a diameter of 40-60 m.m. 
At first the smut is enclosed in a whitish skin, which is ruptured 
into shreds to allow the escape of the black spore-powder. 
After the smut-spores are shed, there remains a stiff skeleton 
consisting of the fibrovascular bundles of the aborted ear." 

The spores are distinguished from those of Ust. maydis by 
their greater size (9-1 5^t), and their almost smooth membrane 
with very small spines. According to Brefeld, the spores are 
capable of germination in nutritive solutions after eight years. 
In the fresh condition they germinate in water to a limited 
extent, producing multicellular promycelia which give off conidia. 
In nutritive solutions they germinate and produce thick promy- 
celia with three or four cells, from which multitudes of conidia 
(5-12/x long and 3 -5m broad) are abjointed. The conidia 
fall off and sprout till the nutritive substratum is exhausted, 
when they give rise to thread-like conidia which do not coalesce. 
If kept dry the conidia easily retain their vitality for months. 

Klihn distinguishes further Sorosporium Ehrenbergii Klihn on Sorghum 
cernuum. 

Ust. cruenta Klihn.^ Another parasite on the ears of 
Soiyhnm. It is described by Klihn as follows : " On the 
spikelets little reddish-brown protuberances of roundish or 
oblong shape are formed and enclose moderately-sized masses 
of dark-red smut-powder. If the pustules are very numerous 
they coalesce with each other, and the branches of the ear 
become more or less shortened, thickened, and twisted. Where 

^Norton, " Ustilago Reiliana," Botanical Gazette, 1895, p. 462. 
■•'Kiihn, "Die Brandforinen der Sorghnm-arten," Mittheil d. Vfx. f. Erdkundf 
7M Halle, 1877. 

•■^ Kiihn {loc. cit.) and Hamhur<ier Garten- Zeitunrj, Bd. 28. 
Brefeld, Heft v., p. 91. 



USTILAIJO. 



283 



the pustules are fewer in number the parts of the ear retain 
their normal position, but all the tloral organs contained in 
the glumes are wholly or partially converted into irregular 
greyish smut-masses. Isolated pustules may occur under the 
inflorescence, on the next internode of the haulm." 




Fn:. V>:i. — i'»tiUiij<i fiueiUa. Simit nf l)mT;i ur SorK'liuni. The head ht»8 heoii 
divided up;ind the inolateii bruni.-heH i)hot<ij,'ra|)hed. The ovaries are tniiisforiiied 
ti) liiiif<i'riii>ked HacM, and iMistule-like oiitirrowthH are also preHeiit <>ii stalkk-ts and 
Mtjdks. (v. Tubeiif i>hi>t. frc.tn material supiilied liy Prof. Dr. .lul. KlUin.) 



The spores are yclhtw to lunwii in ctilnur, smooth-walled, 
and of very variable shai)e, 5-1 2/x long and ."-O/i broad. As 
a rule, germination in water results in the formation of a germ- 
tube compo.sed of I'oui- or live cells, which elongate to long 
mycelial threads or, t'.xccjitionally, produce a .siugh! eonidium. 
As a result of '_;ermiMation in nuln'lixc sohitions, a Hxflv 



284 



USTILAGINEAE. 



formation of conidia ensues ; the conidia multiply in a yeast- 
like manner, and only grow out as hypliae on exhaustion of 
nutritive material. Infection takes place on seedling-plants. 

Kiilin cultivated this species on SorgMim saccharatum and S. vulgare, 
and suggests that a common disease of Durra in South Africa may be 
caused by this parasite. 

Ust. sorghi (Link.) {list. Tidasnei Kiihn) (U.S. America). 
This is another widely distributed parasite of Sorghum vulgare 
and S. saccharatnin. Its external appearance is described by 
Klihn somewhat as follows : " Diseased plants attain to almost 
their normal size, and the flower-head is developed as far as 
the glumes. The ovary, however, is completely metamorphosed 
into a sac filled with spores, its outer wall forming a delicate 




Fig. 154. — UstUago cruenta. Spikelet 
enlarged from a head of Sorghum. The 
ovaries are transformed into long flask- 
shaped sacs, from slits of which the 
spores are emerging as a black powder. 
1 natural si^.e. (v. Tubouf del.) 




Fig. 155. — UstUago cruenta. Gennin- 
ating and sprouting conidia from a 
cnltivation in plum-gelatine, (v. Tubeuf 
del.) 



whitish coat, which is easily torn, and, when the spores have 
escaped, a columella will be found to occupy the centre of the 
smut-mass. The stamens may also become filled with spores, 
and be externally more or less irrecognizable. As a rule, all the 
flowers of a head are smutty; if any escape, they remain more 
or less rudimentary." 

The spores, according to Brefeld, germinate onlg in nutritive 
solutions. They produce a four-celled promycelium, on which 
few conidia are formed. 

Ust. sacchari Ilabh. Dust-brand of cane sugar. This fungus 
injures the stems and head's of Saccharum officinale, S. cglindricum, 
and >S'. Erianthi in Italy, Africa, and Java. 

Ust. sacchari-ciliaris Bref. occurs on Saccharum ciliarc near 
Calcutta. 

Ust. avenae (Pers.). The smut or brand of the oat occurs 



USTILAGO. 



•285 



very frequently on Avcna satica, alsu un A ccnu oriiutalis, 
A. fataa, and A. stricjom in Europe and North America. So 
common is it that one seldom sees a field of oats free from the 
black smutted ears (Fig. 156). 

All parts of the liower are attacked, the ovary, stamens, 
tflumes, and even the awns. The grains become filled with 
the black spore-powder, which shows throuuh the transparent 




Fio. 150. — UtliUigo avenae. The Oat-siiiut ou Avtna mtira. (v. Tubeuf phot.) 

membrane (jf the ovary wall. Tlie diseased ears emerge from 
their enclosing leaf-sheaths, and become exposed to wind and 
rain, under the effects of which the delicate mend»rane soon 
Itecomes ruptured and the spores are blown or washed away, 
till only the axes of the spikelet are left witli a few raL;ged 
remains of the flower. As a rule every shoot of a plant and 
all the grains of an ear are attacked ; if single grains do escape, 
they remain poorly developed. 

'I'he spores (O-S^i) have a smooth or slightly granular coat, and 



286 U8TILAGINEAE. 

retain their capacity for germination for years. In water they 
germinate immediately, and produce a single (rarely two) promy- 
celium consisting of four or live cells, from the ends or partition- 
walls of which oblong conidia continue to be abjointed for about 
two days. The cells of promycelia may become connected with 
one another by lateral branchlets. Delicate germ-tubes are 
given oft' by the promycelial cells, by the conidia, or by secondary 
conidia. In nutritive solutions, on the other hand, the spores 
germinate much more vigorously, the promycelium is stronger, 
the conidia are continuously abjointed from little sterigmata, 
and go on sprouting in a yeast-like manner till, on exhaustion of 
the nutriment, they germinate to form vigorous mycelial filaments. 
The fusion of the cells of promycelia never takes place in nutritive 
solutions. 

The infection of oat-plants takes place on the soil by means of 
the germ-tubes produced from the conidia, promycelia, or spores.^ 
These infect the first leaf-sheath — that one which on germination 
emerges from the ruptured seed-coats as a whitish or yellowish- 
green shining shoot, and continues to grow as a sharp-pointed 
cylinder till, pierced by the first green leaf, it dries up. In 
36 to 48 hours after infection, mycelial threads were found 
to have pierced the epidermal walls, and to have branched freely 
in the tissues. The mycelium grows from the leaf- sheath into 
the first green leaf, passes straight through it into the second, 
and so on till it reaches the haulm or stem." The young 
mycelium grows steadily onwards, and the plasma of older 
hyphae passes over into it. In this way the fungus keeps 
pace with the host-plant, exhibiting externally no symptom 
of its presence till the flowers are reached, where the chlamydo- 
spores are formed. 

Sterilization of seed-corn by Jensen's hot-water method is 
strongly recommended.^ In America, steeps containing potassium 
sulphide, copper sulphate, or lime are also used. As preventive 
against infection, late sowing is advisable. This is founded on 
Brefeld's investigations, in which he found that oat-smut gerniin- 

iWolf, Der Brand den Getrtides, 1874. ' 

2 According to Kiihn, and in Brefeld's infections (Heft xi. , 1895), the majority 
of the germinating conidia are said to penetrate into the young shoot-axis. 

•'"Treatment of Smuts of Oats and Wheat," U.S. Department of Agriculture, 
Farmers'' Bulletin No. 5, 1892; "Grain-smuts and tlieir prevention," Yearbook 
of U.S. DejA. of Agriculture, 1894. 



USTILAGO. 



287 



atecl best at IOC, and not so well above lo C. This 
conclusion is supported by experiments of Kellermann and 
Swindle. Xeither these investigators nor Jensen, however, auree 




Flii. I'.T. — ^,<^7(^'/f» i,.,;,i.nn,i.i (III Ar,l..,nitl,f, II,. i .lul,," ((l;it ^rni.^,-). Till.' K'n'in^ 
are transfoririL-d into bliick Himit-ina.sses ; the aiiiieurniico of the infected spikelct!* 
is quite distinct from tliat of the healthy one to tlio rij{ht. (v. Tul'cuf ]>Iiot.) 



with Urefeld's view, that the fuiiunis is inlniduet'd inin tii-lds 
with fresh farmyard manuri'. 

Ki-llrniiaiiii iiiid Swiiij^le li;ivf found a simit oii nats in AiiuTiia wliicli 
tlicv ili>tiii;,Miisli as U»t. avenue vitr. lerig. 

Ust. Kolleri Willf. This is aimtluT sjit'cios of oat-siiiiit icnntlv (li> 
tiiit^uiHlied ; it has smooth spon-s, and is said to causf i-vi-ii irivatt r dainai,'** 
than U»t. areiiiie. 




288 USTILAGINEAE. 

Ust. perennans Eostr.^ This smut or dust-brand occurs 
frequently in the tiowers of Arrhenatherum elatius (Fig. 157). 
The mycelium perennates in the rhizome. 

An Ustilago nearly allied 
to the preceding one occurs 
also on Festuca iwatcn&is, 
Lolium pcrenne, and other 
grasses. 

The Smut of Barley. 
There are really two species 
of Udilago found on barley, 

¥u:. ib^.—Ustilafjo iiermnans. Spore-culture jjf l^nvrlri anrl JUf tnirln 

in plum-gelatine, (v. Tubeuf del ) ^^''- 'wiaci dUQ U SI. nUCia. 

Ust. hordei (Pers.) {Ust. 
Jcnseni Eostr.) (Britain and U.S. America). This has black 
spherical spores (6'5 to 7'5ya in diameter), which germinate 
and give off conidia from a promycelium. The spikelets gene- 
rally remain enclosed in their coverings. Treatment of seed- 
corn with a half per cent, copper steep is a certain remedy. 

Ust. nuda (Jens.) (U.S. America). In ears diseased by this 
smut the epidermis of the glumes is early lost, so that the 
spore-powder lies freely exposed when the ears emerge from 
the leaf-sheath. The spores on germination give off a four- 
celled promycelium, which however produces no conidia, but 
develops directly to a septate mycelium. The spores are 
smooth-coated and oval (5-7m long and 5-6'5/>i broad); they 
are matured and set free at the flowering season of the barley, 
and probably infect seedlings in spring. The spores of this 
smut are very resistant against treatment with copper steeps, 
and it is recommended to soften the barley for several hours 
in cold water before applying Jensen's method. 

Ust. tritici (Pers.) (Britain and U.S. America). Wheat-brand. 
The spores are developed in the ovary of the wheat, and are 
black with a tinge of olive-green. On germination they im- 
mediately form a non-septate mycelium (Fig. 160). 

Henning^ has descinbed spore-cushions on the leaves and leaf-sheaths of 
Triticum vulgare in Upper Egypt. 

Ust. bullata Berk, on Triticum orientate in Turkestan. 

iRostrup, Uatilwiineae Daniae, 1890. 

- Heuning, Ztitschrift f. Pflanzenkrankheiten, 1S94. 



USTILAGO. 



289 



Ust. secalis llal^enli. IJye-ln'and. This occurs but rarely, 
and tk'Stroys only the grain. 

Ust. panici-miliacei (Pers.) {Ust. destruens Buby). Smut 
of Millet. Tlii.s .-iuiuL occurs on the tiowers of Panicum milia- 




VU: l.'jjt. — Uttilago hni-ilet. Uiirluy-snnit mi llonltum diitiehnni, (v. Tulx'tif pliot.) 



irii/i), 1'. ihnrt<ifjiiiivn)ii\ and I', Ci iis-i/a//i in Italy, Franco, 
(lerniany, and North America. Sometimes it is very abundant 
and cau.ses great danmge. The mycelium makes its way into 
\"iiii'_' ]ilants and grows upwards with ibi-in, |M'netrating everv 

1 



■290 



USTILAGINEAE. 



shoot. Spores are developed only in the inflorescence, which 
in consequence fails to reach its full development as a panicle, 
and remains more or less spike-like and enclosed in a leaf- 
sheath. The parts of the inflorescence become completely filled 




Fio. WO.—Ustilago tritici. Wheat-smut. The central ear is normal and 
healthy, the others are smutted and most of the spores are alreadj' shed, 
(v. Tubeuf phot.) 

with a sporogenous mycelium from which arise the spore-masses ; 
these are at first enclosed in whitish coverings consisting of 
tissues of the host-plant, but when mature they escape as a black 
dust or powder. 



USTILAGO. 291 

The spores are smooth-coated and spherical or elliptical, 9-12/x 
long, aud 8-10/x broad. According to Brefeld, they germinate 
in two or three days in water, and produce promycelia with four 
or five cells ; the cells may either bud out directly and become 
hyphae, or do so after previous fusion. 

Spores placed in nutritive solutions germinate in about three 
days, and produce several strong septate promycelia with spindle- 
shaped conidia. The conidia as a rule germinate directly into 
branching hyphae ; fusion of conidia is not known, and secondary 
Conidia are only rarely formed. The hyphae become septate 
in their older parts, and produce conidia in two ways, firstly, 
from hyphae in the solution itself; secondly, from aerial hyphal 
branches which rise out of the solution and give off conidia 
in a manner similar to mould-fungi, 

Brefeld states that infection takes place by means of the 
germinating conidia. Only resting-spores are produced on the 
plant itself, and these retain their capacity for germination 
for years. 

Ust. Rabenhorstiana Kiihn^ (U.S. America). This is found 
on Punicani miliaccui/i, P. (jlahram, P. lincarc, and P. sanyuinale. 
It destroys flowers, ears, and upper part of haulms. The spores 
are brown and spiny ; they germinate, but do not produce 
conidia. 

Ust. sphaerogena Burrill. An American species causing 
distortion of the spikelets of Punicinii Cnis-ijalli. The malforma- 
tions resemble those produced on the same host by Toli/posporium 
hullatum, but differ in having a rough surface with short rigid 
hairs. The spores are free and germinate easily in water, 
producing promycelia which give olf conidia. Tlie conitlia 
frequently si)rout for a time in a yeast-like manner. 

Tlic fi)ll<)Nviii'^' ;iie Ainerieau species : 
Ust. diplospora KII et Ev. On Fanicum sanfptiiudf. 
Ust. trichophora Lk. < )ii Panicimi colimnn. 

Ust. setariae iJulili. On I'atiicum sanguinalc ; pioUably iileiitical witli 
Ust. Uahenhorstiamt. 

Ust. panici-leucophaei I'.nf. On Panicum leucojihaeum in IJio tie Janeiio. 

Ust. digitariae ivzc occur.s on tlie tlowers of J'anicinn 
{Dlijitariii) sniii/iuiutlr, P. i/htJu-i/iii, uml /'. irpens. The spores 
are smooth-walb-d. 

' Kulni, J/.</iri,ji,i, |S7(J. 



292 USTILAGINEAE. 

Ust. panici-frumentacei Bref.^ is found on Fanicum frumcn- 
iaccam, a cultivated Himalayan millet. Only isolated grains 
in an ear are attacked, becoming enlarged to twice their 
normal size. Germination of spores takes place sparingly in 
water, but abundantly in nutritive solutions. Two-celled promy- 
celia are produced bearing numerous sprouting conidia. On 
exhaustion of nutrition, the conidia give off one or two filaments 
on the surface of the liquid, and from these other sprouting 
conidia arise. 

Ust. Crameri Ivorn. completely destroys the ovaries of Setaria 
italica, S. ciridis, and S. amhigua, leaving only the outer wall 
as an enclosure for the spore-powder. The spores are brown, 
smooth-walled, and 6-9 ^i broad, 10-12/x long. The promycelia 
consist of four or five cells, which in water as well as nutritive 
solutions grow out into long threads without producing conidia. 

Ust. neglecta Niessl fills with its black spore-powder the 
ovaries of Scfaria glauca, S. verticillata, and S. viridis. The 
cells of the promycelium develop into a mycelium without pio- 
duction of conidia. 

Ust. Kolaczekii Kului. On Setaria genicidata in Berlin Botanic Gaiden. 

Ust. bromivora Fisch. (Britain and U.S. America). This 
appears in flowers of species of Bromus, so that the ovaries 
become filled with a dark-brown or black spore-powder, but 
the glumes or heads undergo no deformation. The spores are 
smooth, and on germination in water produce only a spindle- 
shaped one-celled (rarely two-celled) promycelium ; in nutritive 
solutions, Brefeld found they generally produced two-celled 
promycelia, bearing conidia from which are produced further 
promycelia with conidia ; yeast-like colonies are never formed. 

Ust. ischaemi Fuck, attacks AndrojJogon Ischaemum. The 
inflorescences remain almost completely enclosed in the upper- 
most leaf-sheath, and are destroyed except their axes. The 
spores are brown and smooth-walled. Brefeld states that in 
nutritive solutions they produce conidia which remain adherent 
to the pronn^celium and grow out into long hyphae with*out 
coalescing. 

Ust. andropogonis-tuberculati Bi'ef. on Andropogon tzd>ercuh(tiim ficni 
Simla. 

Ust. andropogonis-annulati Bief. on Andropngon annvlatinn from Cnlciitta. 

1 Brefeia, Schhnmelrnh'', Heft xii., 1895. 



u.STiLA(;o. 293 

Ust. grandis Fries, lieed-smut. (Britain.) This frequents the 
liiiuhns itt Pliiii'jinite.'i counnunis (also Ti/j>/ii> /(itifoliu and T. 
minor); the internodes of the host in consequence swell nut 
and appear as if the stem carried one or more bulrush-heads. 
The mycelium permeates the whole host-tissue and produces 
spores, which escape as a hlack dust on rupture of the epidermis. 
According,' to Kiihn, the spores are capable of immediate ger- 
mination and retain their vitality for a whole year. A 
ftiur-celled promycelium is produced and becomes detached from 
the spore ; then follows an abjunction of oblong conidia from 
the septa of the promycelium. In nutritive solutions, lUefeld 
found that germination took place in the same way, but mure 
rapidly and vigorously. Xumerous conidia are produced, but 
these only rarely give oft' secondary conidia, and then only a 
single one : more conmiouly they i)roduce promycelia, as the 
spores did, and conidia again arise from these ; yeast-like 
sprouting does not occur. The resting-spores may continue 
to give oft' promycelia in succession for some time. On ex- 
haustion of nutrition the cells of the promycelium, as well 
as the conidia, develop into mycelial threads, to which alone 
15refeld ascribes the capacity for infecti<jn. 

Ust. longissima (Sow.) (Britain and T.S. America). This 
forms eloiigalci] lirown spore-patches on the leaves of various 
species of Glycerio. Brefeld states that tlie smooth sjiherical 
spores germinate in water, and give off a short uniecliuLir 
]»romyceliuni which undergoes no further development. In 
nutritive .solutions the .spores germinate in like manner, but 
the promycelium becomes thread-like and septate, and gives 
oH' conidia laterally ; new promycelia continue to be given 
oH' from a cell which remains behind inside the spore, and the 
conidia ultimaltdy develop into liy])hae. 

Ust. hypodytes (Schleeht). This species forms dark smutiy 
C(jatings mi liaulms anil leaf-sheatlis of (Ui/ccria Jluitans, Dijt- 
hiclniis Jioii'i, yli/riijji/rinn rrpt-ns, ('(iltivuff/rastis ipiijiii, Psminiiii 
(I ir an rid, Stipn pi/iiuidi and X capillar is, JiruinKs creel us, Trilivinn 
npciu^ and T. vvhjarc, Ehimns arenariiis, Panicum repcns, Pliraij- 
inifis cininnunis, Arinnliiuiria, etc. 'I'hr sjiores an' brown, 
smooth-walled, and irregularly sphtrical or tpiadrangidar : ihi-y 
;4fniiiiiaii' in water or nutritive solutions, producing mycelia 
<Hrert, without j)revious Ibnnat inn ot' ronidia. 



294 USTILAGINEAE. 

Ust. grammica B. et B. is reported on haulms of Aira and Glyoerid 
in England. 

Ust. echinata Schroet. produces smut-strips on leaves of Phalaris 
urundimicea. (U.S. Amer.) 

Ust. cynodontis Henn. On Cynodon Dactylon from Simla. 

Ust. arundinellae Bref. On Arundinella near Calcutta. 

Ust. aristidae-cyanthae Bref. On Aristida cyantha from Himalaya. 

Ust. coicis Bief. On Coix lacryma from Simla. 

Ust. esculenta Heini.i causes deformation of plants of Zizania latifolia 
in Tonquin and Japan. The deformed parts are eaten, while the spores 
are used for dying of hair and eye-brows, as well as in the manufacture 
of a varnish. 

Ust, paspalus-dilatati Henn. On Faspalus dilatatus. 

Ust. olivacea D. C. frequents species of Carcx. The olive- 
brown spore- masses hang loose and fleecy from the destroyed 
ovary. The spores, according to Brefeld, are produced from 
long hyphae which become thickened at intervals and broken 
up by cross-septa into portions corresponding to the future 
spores. The hyphae, however, are not completely given up to 
spore-formation, but parts remain and form fine filaments which 
give the fleecy appearance to the ruptured ovaries. Germina- 
tion in water results in the formation of a single conidium, a 
second being rarely formed. In nutritive solutions similar 
conidia are produced one after another successively, and sprout 
off conidia in a yeast-like manner without the formation of pro- 
mycelia. On failure of nutriment, hyphae are finally produced. 

Ust. Vuijkii Oudem. et Beyerk. The ovaries of Luzula 
camjpestris become filled with spores, some colourless, some 
light-brown. The sjDores germinate in water, giving four-celled 
promycelia with ovoid conidia, which do not, however, coalesce 
or develop further, even in nutritive solutions. 

Ust. capensis Eees. In fruit of Juncus. 
Ust. luzulae Sacc. In fruit of Luzida. 

Ust. scabiosae (Sow.)'^ {Ust. Jiosculorum Tul.). (Britain.) The 
antlievs of Knautia and Scabiosa attacked by this fungus become 
filled with a flesh-coloured to violet spore-powder, and swell 
to little sacs. The flowers otherwise are but little altered. 
Brefeld found that spores from Knautia arvcnsis germinate 
easily and abundantly in water, and produce promycelia con- 

' P. Henniiigs, Hedicitjia, lS9o; Miyabe, Tokio Botanical Magazine, 1895. 
-Fischer v. Waldheim, Bot. Zeitung, 1867. 



USTILAGO. 



295 



sisting of three or four cells with conidia, and sometimes 
secondary conidia. Coalescence of conidia may take place, and 
thereafter production of little mycelial threads. In nutritive 
solutions everything proceeds more luxuriantly, and conidia are 
produced in lan^^e numbers ; they are easily detached and sprout 




Fio. 161. — U»tila{/o truj/opogonis. Plants of Tragofmgon in flower luid fruit- 
1, numiiil fniit ; 2 and 3, normal flowers; 4, two nurniiil flower-lmds. Tlic 
reiii:iinin({ sitcciniens arc uttuckcd by tliu fiingu.M, and, in consequence, remain 
in tlie bud cniidition, and fiUeil witli black spores wliich escape liy tlie opening of 
the involucre, (v. Tuljeuf phot.) 



yeast-like, till, on deficiency nl' mitritinn, t'usioii ;iiid siil>se([U('nt 
geiliiinalinii takes jilace. 

Ust. intermedia Schroel. {Usf. j!osci(/<>nim ]).(".) (ih-itain). 
The anthers of >>aihius<i (Jolinnlxirid hecome filled with the dark 
violet spores of this smut. The spores germinate in water, 
and, according to l>refehl, jtroduce three-celled ])romycelia with 
few cdnidia : smne of these, as well as the cells of the pruliiy- 



296 



U8TILAGINEAE. 




celia, may develop to mycelia; coalescence of conidia is unknown. 
In nutritive solutions conidia are formed in large numbers, and 
multiply yeast-like till nutriment fails. 

Ust. succisae Magn.^ frequents the anthers of Scahiosa Siiccisa, 
and forms jjure white spores, easily distinguished from those 
of the two preceding species. The anthers appear to be thickly 
covered with glassy granules. The spores produce four-celled 
promycelia from which conidia are formed. (Britain.) 

Ust. tragopogonis (Pers.) (Britain). 
This fungus forms its spores in flowers 
of species of Trarjoyogon, and in many 
localities has a wide distribution. 
The development of the flower is 
retarded, so that it retains externally 
the appearance of a flower-bud en- 
closed in its bracts (Fig. 161). The 
dark- brown or violet spores escape 
through intervals between the bracts-; 
they are 13-17/a long, 10-15// broad, 
with reticulate markings on their 
coats. They easily produce in water 
four or five- celled promycelia from 
which conidia are given off, often 
followed by coalescence. In nutritive 
solutions development is much more 
vigorous, secondary conidia may be 
produced, and coalescence always takes place. 

Ust. scorzonerae (Alb. et Schwein.) is at first sight very 
similar to TJ^t. fragopogonis. Its spores are found in flowers 
of Scorzonera liumilis, Sc. 'purpurea, and cultivated species, e.g. 
Sc. Iiispanica ; while its mycelium hibernates in the perennial 
root-stocks of these. The spores are produced rapidly and 
in large numbers ; tliey germinate easily in water, forming a 
four-celled promycelium, and thereafter conidia wliich do not 
pair. 

Ust. cardui Fisch. v. Waldh. (Britain). This is the cause 
of a stunting of the flower-heads of Carduus acanthoides, C. 
nutans, and Silyhmn Marianum, while at the same time they 
become filled with a brownish-violet spore-powder. The spores 

' Magnus, Hedwiijia, 1875. 



Fig. 162. — Ustilago tragopogonis. 
Development of spores : successive 
stages of development, in ordei- of 
the letters, a, Sporogenous branch, 
just appearing on the surface of 
yoxmg corolla of Tragopogon pra- 
tcnsis, and beginning to form a tuft 
of branchlets. b and c, Formation of 
spores from the mycelium, d, Spore- 
clump with several ripe spores, the 
episporium of which is coloured 
dark-violet and thickened in a 
reticulate manner, (x 300). (After 
De Bary.) 



usTiLA(;o. 297 

are about 'lO/x in diameter, and torin in water pruniycelia with 
conidia. In nutritive solutions Brefeld found conidia produced 
in large numbers, and multiplying by yeast-budding. The 
proniycelial cells grow out as septate branched twigs, from 
which conidia are abjointed, and after coalescing in pairs, produce 
germ-tubes. 

Ust. violacea (Pers.).^ Carnation-smut (liritain and U.S. 
America). In Silc/tc, Viscaria, Sapoaaria, DinntJuis, Stcllaria, 
Malachium, Cerastium, and Lijclmis, the pollen sacs of other- 
wise well-developed flowers become filled with dark-violet 
spores, which escape and discolour the other tloral parts. 
Pistillate tlowers of Lychnis attacked by this fungus develop 
stamens containing the smut-spores (p. 27). On germination 
in water, promycelia of three or four cells are formed, and 
become detached from the spores. Primary and even secondary 
conidia are produced, while coalescence of promycelial cells and 
conidia is connnon ; but only a few of them produce germ- 
tulies. In nutritive solution, according to Pirefeld, everything 
proceeds much more vigorously; from tiny conidiophores on the 
promycelia numerous conidia are produced in succession, and 
from these other conidia are budded off like yeast-cells till 
nutriment fails, when they grow out to form hyphae. The 
conidia are longer than those formed in the water-cultures, 
and coalesce in pairs to give rise to longer and stronger 
germ-tubes. 

Ust. holostei Dt- Baiy nii Hnhistexm xmbeUdtK/n. Tin- Imst-ovaiies 
become tilled with .spores which genuinate to fnur-ccllt'il i»ri>iiiv(ilia fioiu 
which paiiiiiLT sporidia arc formed. 

Ust. Duriaeana Till. In the ovary of Cerastium. 

Ust. major Schroet. On Silene Otites. Tlu- spores •^cnninatt- <>\\\y in 
nntritivc solutions. (Britain.) 

Ust. seminum .Tnt-I. In tin- ovules <if ArnhiK petraen in Scamlinav ia. 
Tlic spores on germination produce sinijile hyphae. 

Ust. entorrhiza Schroet. In root-cells of /'isuin sa fir not. 

Ust. pinguicolae Pustr. nn Finf/nicida ni/tj(tris in Denmark. 
.V<ciirding l<i Ihrtuld, the spores germinate ecjually in water or 
nutritive solutions, forming thn'e-celled promycelia, whieh scparaie 
iVoin the spore and bud olf coniilia fKim cadi cell. 

' Tuliisne, Ann. il. m-imrfH iiatiir., .Ser. III., \'<>i. vil., 1S47. 
Atkinson (Aiiu rii-an ('ftnififiou Sofiili/, I89.S), ilcHcriln's tliis and oilu-r mimtM 
fre<|iu'iiiiii)4 .\iiifiiuiin CiiriiiitioiiM. (Kdit.) 



298 USTILAGINEAK. 

Ust. betonicae Beck/ occurs in the anthers of Bctonica 
Alopemrus. Its spores are larger than those of Ust. violacea, 
and have larger-meshed reticulations on the spore-coat. The 
spores germinate in water, and as a rule produce a three-celled 
promycelium from which conidia are abjointed. These at once, 
or after production of conidia, coalesce in pairs and give off germ- 
tubes. In nutritive solutions germination takes place much 
more vigorously, numerous conidia are formed and continue to 
bud off new conidia till the nutriment is exhausted, when 
coalescence of conidia and development of hyphae takes place. 

Ust. bistortarum D. C. frequents leaves of Polygonum and 
Buiiicx. (Britain and U.S. America.) Brefeld states that the 
spores are dark-red and germinate to four-celled proniycelia, 
from which conidia are produced and readily coalesce, especially 
in presence of abundant nutriment. 

Ust. marginalis (Lk.) on Polygonum. Bistorta. The spore-masses 
are dark-violet, and occur chiefly on the margins of the leaves. 
The spores germinate in water and produce a four-celled promy- 
celium with oval conidia, which do not sprout, but either pair 
or grow out as hyphae. 

Ust. anomala Kunze. On leaves and in ovaries of Polygonum (U.S. America;. 

Ust. utriculosa (Nees). In ovaries and anthers of Polygonum. The 
greyish-violet spores, Brefeld says, germinate during the following summer, 
and give off four-celled promycelia with conidia which do not coalesce in 
pairs. (Britain and U.S. America.) 

Ust. Parlatorei Fisch. On twigs and leaves of Riimex maritimus and 11. 
ohtusifolius. 

Ust. Kuhneana Wolf. Inhabits all parts of Ruraex Acetosa and R. Aceto- 
sella (Britain). 

Ust. Goeppertiana Schroet. On Rumex Acetosa, especially in leaves and 
leaf-petioles. The spores germinate in water or nutritive solution. The 
jn'omycelium is unicellular and remains inside the spore, giving off a single 
conidium, which for a time buds off other conidia {Ust. olivacea alone behaves 
in this same way). 

Ust. Molleri Bref. On Polygonum hispidum. 

Ust. Koordersiana Bref. On Polygonum harhntum in Java. 

Ust. domestica Bref. On Rumex domesticvs in Norway. 

Ust. vinosa (Berk.). On fruits of Oxyria (Britain and U.S. America). The 
spores germinate in water or nutritive solutions, and jjroduce a four-celled 
promycelium from which conidia are given off, especially in nutriti^'e 
solutions ; the conidia ultimately produce germ-tubes. 

^ Zooloii.-hotan. Ge-'^el/., Vienna, 1880. 



USTILAGO. 2'J9 

Ust. Vaillantii Tul.^ appears in the anthers and ovaries of 
Gf.ifjca, SciU", Mii-^cari, etc. The perianth of diseased Howers 
remains, but is somewhat enlarged. The ovaries and anthers 
become filled with spores ; the latter organs are, however, fully 
developed and may even contain pollen-grains mixed with spores. 
According to Brefeld, the spores germinate easily in water and in 
nutritive solution. A promycelium is formed which, after detach- 
ment from the spore, becomes three-celled and develops conidiu. 
These sprout for some time, then produce three-celled promycelia. 
Ust. ornithogali (Sclim. et Kze) forms leaf-swellings on Ornitliogalum and 

Ust. tulipae (Heud.) produces swellings on the leaves of the tulip. 
Ust. plumbea Rostr. occurs on leaves of Arxim maculatum in Denniaik. 
Ust. ficuum Reich. In the fruits of Ficus Carica in Asia Minor. 
Ust. Trabutiana Sacc. In berries of Dracaena Draco in Algeria. 

Ust. Vrieseana Vuill.- In the Botanic Garden at Amster- 
dam, the roots of several species of Eucalyptus exhibited woody 
tumours from which proceeded outgrowths resembling " witches' 
brooms." These contained the mycelium of an Usfilcfjo which 
produced spores in the cortical tissues. 

Ust ('.) adoxae Bref. On Ado.ra moschateUina in cells of the suliterranean 
stem. TIu' spnn-s ])ro(luced only simple filaments without coniilia. 
Ust. Lagerheimii l>ref. On linviea from Quito. 
Ust. Schweinfurthiana Thiini. On Imperata cylindnCa from Cairo. 
Ust. boutelouae-humilis Href. On Boxiteloim hinnilis iroxw Quito. 
Ust. Ulei Henn. On Cldoris. 
Ust. spinificis Ludw. On Spiiu'fe.r hirsuta from Adelaide, Australia. 

Ust. Treubii Solms.*^ This Javanese fungus and the galls 
produced by it deserve a somewhat lengthened notice im acciiuni 
of their general biological interest. It causes a hyiiertrojihy on 
Fvli/fjiminn rhiucnsc in Java, which further exemplities the 
phenomena already iKiticed in ciMiiiectinii wiili ('an'iiid di/on/Kdis 
on Tlmjopsis (p. oO). 

The stems at attackeil jijaccs show strong liyperirii[ihy and 
great change in their analnmical structure. Solms designates 
the thickeiiiiiL:s, in c(jiiininii with those caused by Citroinn 

''I'lilasiie, Ann. d. srieiict natur., Ser. III., Vol. vii., 1S47, with pliites of Miisrrtri. 
Wortli (J. Smith (G'anlnur'n C/irrntl'fi, XV., 1S!I4, p. 4('>."{), give« a Jiguro 
and note on occurrence of tliix Hiiiiit in llritiiiii. il'ldit.) 

-'Vuilleiniii, Coui/'t. runt., 1S'.I4. 

'.'*<ohiiM, Amid/, i/ii Jnrilin Iniiiii. il> /tiiif' ii:or<i. \'i>l. \1., ISSCiST, p. 7'.!. 



300 U.STILA(aNEAE. 

deformans and Peridcrmiv/iii datinum, as " vegetative canker- 
galls." On those places are crowded fleshy brittle outgrowths, 
consisting of an irregular bent club-like stalk, longitudinally 
furrowed; and expanded at its upper extremity into a broadened 
head containing the UsHIckjo spores. Solms calls these out- 
growtlis " fruiting galls," ^ and he describes them as follows : 
" if one of these protuberances be divided, the spore deposit will 
be found as a flattened violet layer, extending to the margins 
of the head and roofed in by a slight plate of tissue. This 
last becomes ruptured, shrivelled, and brown. The violet 
spores are thus set free, along with a loose woolly capillitium- 
tissue, which apparently facilitates distribution of the spores 
by rendering them difticult to moisten, a contingency very 
likely to happen in the heavy tropical rains of Java, and with 
the result that germination would occur before the spores had 
time to be transported to a new host. After shedding of the 
spores, the succulent stalk remains. The fruit-galls consist of 
a hypertropliied tissue developed from the cambium; they flrst 
emerge as roundish naked protuljerances, covered externally by 
a smooth epidermis, and containing a meristem from which 
fibrovascular bundles are developed. The galls are composed 
of a homogenous parenchyma of large thin-walled cells, elongated 
in the direction of the long axis of the galls, and containing 
large cell-nuclei. The epidermis consists of little, polygonal, 
nucleated cells, and is pierced by a few stomata. The galls 
are internally permeated by a number of irregularly arranged 
fibrovascular bundles which show a slightly developed wood 
and bast region. As the anterior end of the fruit-gall elongates, 
the bundles keep pace by repeated forkings, and form a 
system of branches diverging at very acute angles and ter- 
minating a short distance from the surface of the gall. The 
violet-brown sporogenous layer is situated just at the termination 
of the bundles, and is covered by a slight layer of parenchyma 
under the epidermis. The sporogenous layer appears as if 
composed of columns arranged beside one another in a palisade 
manner, and connected above and below with the enclosing 
tissues. At the margins of a section the columns easily separate, 
and will be seen to consist of a central strand of elongated 
cylindrical cells filled with a reddish gum-like mass. The cells 

^ Fruclityixllen. 



USTILAGO. 301 

belong to the tissue of tlie I'vhjiitniu m and nmy turni simple 
filaments, or several sucli filaments may become bound together 
by lateral connections. Each strand becomes surrounded by 
spores of the Vstikujo which are set free on rupture <tf the 
fruit-gall, while the cell-strands laterally bound to each other 
are loosened from the surrounding tissue as the capillitium. 

" The spores germinate in water, producing short unicellular 
proniycelia and fairly large conidia, which coalesce before they 
germinate. The mycelium is confined to a snuill part of the 
stem, twigs, or inflorescences of the host-plant. The liyper- 
trophied parts of the stem contain altuurmal spongy wood, 
which easily decomposes and brings about the death of the 
galls, along with parts of the stem situated beyond them, or 
even tlie whole plant. The normal production of cambium is 
completely destroyed in the galls. Tlie pith and primary rind, 
however, remain uninfluenced. Tlie cambium produces, both 
outwards and inwards, such a mass of thin-walled parenchyma 
that the normal bast is forced asunder and disarranged. In 
this way rupture of the sclerenchyma-layer ensues, whereby the 
primary rind is destroyed, and the abnormal tissue formed by 
the cambium emerges to view. It is from such idaces that 
the excrescences described have their origin." 

It will be seen we have here the partners of a syml)iosis 
becoming so adapted to each other that the host-plant ]jr( (duces 
a special tissue for the distribution of the spores. This case 
goes further than most of those already mentioned in .^ 5; 
but the bushes produced l)y Cacoma drfonnans for the formation 
of its spores are again a distinct advance on the " fruit-galls '* 
of this Ustiktf/o. 

Cintractia. 

Spore-masses developed inside a stroma and pas.sing outwards 
S(j that the mature black spores lii; freely exposed. 

Miij,Mms ' Iiiis ifcentlv se|iaratf(l Cittilai/o i-an'riji Pers. and r. .titliincliisti 
Knni.,aml jjlacfd tlioin under this <,'fims, iK'cuust' thrir spoivs ar<' tU'Vi-lopi'il 
only in tiir f|ii(I(iniai cclis nf tin- liost-evaiy. 

Cintractia caricis d'eis.)' ( I'.riiain aud I. S. America). The 

' Cki-mu. AuiiuI. d. xciinriH natin:, Scr. \i., X'ol. .\v., ISS.'t. I'lati- X\'. 
.Ma^,'nlln, liotan. Vtrein d. Prov. Jiniiidt n'mnj, x.x.wii. IJiofi-M, SrhiinmrlpU-^ 
I If ft Ml., IS'.).'.. 



302 



USTILAGINEAE. 



mycelium forms a stroma on the ovary-wall ; there the 
spores originate and pass out to the periphery as they attain 

maturity. The spores adhere in black 
masses, and germinate in water in the 
following spring. A promycelium is pro- 
duced, and on emerging into the air 
becomes divided by means of a cross- 
septum towards its apex ; from both 
cells so formed conidia are developed 
and grow out into germ-tubes without 
previous sprouting. This species occurs 
on many species of Carex, and the 
mycelium perennates in the rhizomes. 
The spores vary somewhat on the 
different hosts. 

C. subinclusa (Korn.) (U.S. America). 
The spores form coal-black masses in the 
ovaries of many species of Carex. They 
develop on a stroma from within out- 
wards, and are more easily detached than 
those of C. caricis ; their coat-markings 
also take the form of thicker and shorter 
processes. On germination in water 
after a resting period, the spores produce 
two-celled promycelia, from the apical 
cell of which an ovoid conidium is 
abjointed, while from the lower cell a lateral conidiophore is 
produced. Xumerous conidia are given off from both cells, and 
grow out without previous sprouting. 

C. (?) sorghi {Bndothlaspis sorghi) Sor. The mycelium envelopes the grain of 
Sorghum cernuum, and fills it with black spore-masses. It has only been 
observed in Asia, 

Other species of Cintractia occur outside of Europe, but are of no 
practical importance. 



FiCi. 163. — Cintractia caricis. 
Two ovaries have been replaced 
by blacVi spherical fungus-fruits ; 
an isolated normal triangular 
ovary is shown in longitudinal 
and cross section, (v. Tubeuf 
del.) 



Sphacelotheca. 

The sporocarp is sharply defined, and consists of a columella 
round which the loose mass of spores is disposed, the whole being 
enclosed in a covering formed by non-sporogenous hyphae. 

Sphacelotheca hydropiperis (Schum.). De Bary describes 



SPHACELOTHECA. 



30^ 



this fungus as follows : ' " Sphacclothaa forms its compouiul 
sporophore in the ovule of its host. When the ovule is normally 
and fully developed in the young flower, the parasite, whicli 
always grows through the flower-stalk into the place of insertion 
of the ovary, sends its hyphae from the funiculus into the ovule, 
where they rise liigher and higher and surround and penetrate 
its tissue to such an extent as 
almost entirely supplant it, and 
thus an ovoid fungns-body of 
densely interwoven hyphae takes 
the place of the ovule. The 
micropylar end of the integu- 
ments alone escapes the change, 
and remains as a conical tip 
(Fig. 164 C) on the apex of the 
fungus-body and gradually turns 
brown and dries up. The fungus- 
body is at first colourless and 
uniformly composed of much- 
branched hyphae, which are 
woven together into a compact 
mass and have the gelatinous 
walls of the simple sporophore of 
Udilaijo to be described below. 
If it 
form 

in ^•olume, differentiation begins 
first in the apical region into a 
comparatively thick outer wall 
whicii is closed all round, an 
axile colunniar cylindrical i)X 
club-shaped body, the columella, 
both parts remaining colourless, 




has retained its ovoid 
as it steadily increased 



Fk;. IiU. — Sjihaeelotheca kydropiperis in the 
flower uf Poli/i/onuni Hydroinita: A, Ripe 
comixtuud sporophore of the fuii),'us project- 
ing from the perianth of the Pulytjonum. 
B, The .s;inie, with the lUiiss of spores eiueof- 
ing from the sporophore. C, Meiiian longi- 
tudinal section through a young fructifiea- 
tion and its environment. ' D, Ivongitudiual 
section through an older sporophore. i-, The 
columella, p, The perianth. /, The wall of 
the ovary. «, The integument (micropyle) of 
the ovule. ;/, The style. In V and D the 
sterile or young tissue of the fungus is 
shaded by longitudinal lines, the mass of 
riiKruing spores is darker. Further ex]>lana- 
tion in the text. (Slightly niagnitied.) 
(After Ue liary.) 



and 



a dense spore-mass 



whi(^li 

fills the sjjace between the two and becomes of a dark \ii>lc'i 
colour (Fig. 104 C, D). The lower ]iari which corresponds to 
the funiculus and chalaza of the ovule n-mains undilferentiated, 
and an aljundant formation of new liyphae is constantly taking 
place ill it. This new formation is so adiled from below to 
the din'erentiat<'(l portion, that the latter constantly iuereascs 
' iJe liiuy, .Vor/ifio/oij!/ and Biolo<jy of thr Fninji, KngliMli KWitioii, p. 173. 



304 USTILAGINEAE. 

in height without becoming niateiially broader, and maintains 
therefore the form of a cylinder pointed at the upper end. 
Where the parts below approach the wall, cohunella, and spore- 
mass, they assume their structure and colour. In other words, 
each of the three portions grows from its base by addition of 
new tissue-elements, which are constantly being produced and 
pushed onwards from a basal formative tissue, and are differen- 
tiated and assume their ultimate form in the order in which 
they are produced (Fig. 164, C and D). The development 
and mature structure of the spore-mass are the same as those 
of Udilago, which will be described presently. The wall in 
its fully developed state is a thick coat formed of many irregular 
layers of small round cells not very firmly united together. 
These cells are formed in the same way as the spores from 
the hyphae of the primary tissue, and are of about the same 
size as the spores with a delicate colourless membrane, and 
for the most part with watery hyaline contents. The columella 
has the structure of the wall, but it usually incloses in its tissue 
evident brownish fragments of the tissue of the ovule, and 
consists at its uppermost extremity of much larger, firmer 
hyaline cells, the origin of which I am unable to explain. I 
may also observe that the upper extremity in young specimens 
always ends blindly in the spore-mass {C), but in some older 
ones reaches to the apical portion of the wall and passes into 
it {D); it is still uncertain whether this is a difference in the 
individual plants or a difference of age. 

" The spore-receptacle which has now been described is formed 
only from the ovule. The perianth and stamens of the fiower 
continue in their normal state. The wall of the ovary and the 
style are also not attacked by the fungus ; they do not follow the 
growth of the spore-receptacle, and as this advances the lateral 
wall is distended and at length bursts transversely ; the style 
with the upper portion of the wall dries up into a small point 
at the apex of the receptacle, which is borne by the latter as 
it grows out of the perianth {A). The wall of the spore- 
receptacle, especially where it is covered above by the withered 
remains of the wall of the ovary, is very fragile, and tears 
asunder at the slightest touch to discharge the spores {B)." 

The dark-violet spores have a finely-warted exospore. 
According to Brefeld, they germinate in water after a resting 



SPHACELOTHKCA. 



305 



period, and produce three-celled promycelia with elongated ovoid 
conidia, which sprout indefinitely. In nutritive solutions twu 
or three promycelia may he produceil. 

Schizonella.' 

The spores are produced in series on the reproductive hyphae. 
At first two-chandjered hy means of a cross-septum, they later 
separate into two loosely-joined cells and form twin-spores ; each 
lialf -criiiinates like an /"^sZ/A/yo-spore. 

Schizonella melanogramma (D. C.) (U.S. America). A 
species found on leaves of various species of Carcx. The spores, 
when mature, escape by short fissures in 
the upper epidermis of the host ; they 
are black and coupled in pairs Ijy a short 
connection. They ;j;erminate in water 
and produce a promycelium of three or 
four cells from whicli conidia are given 
off. In nutritive solution the promycelia 
produce conidia, which fall off and sprout 
yeast-like for a time. 

Tolyposporium. 

The sporogenous hyphae form tangled 
masses, and produce their spores firndy 
bound together in balls. The single 
spores are large, somewhat angular or 
spherical, and each germinates like a 
spore of T^^fihitjiK 

Tolysporium junci (Schroet.) causes (liiftcrworunin.) 
the formation of gall-like outgrowths on 

the ovaries, flower-stalks, and haulms of Jiihchs Inij'tinitis and 
J. capitatus. In these the spores are developed ami escape as 
spore-balls. The spores, after a i)rolt)nged rest, germinate iji 
water and produce four-celled promycelia, from which (»void or 
spindle-shaped conidia are given off. In nutritive solutions many 
of the cells in each spore-ball germinate and ju-oducc pnnnyceiia, 
at first four-celled, later further divided by new septa ; the 
conidia sprout and grow on till they reach the air, where aerial 
conidia are formcil. 

' S.'linK't.T, liinl,,.i„ </. f'jla,r..ii, IM. ii., IsTT. 
I 





Fi(;.lii,'>.- 7'w/.i,/'".</<"--..',,i junci. 
Spore-iu.isM. One ajmro Ijas 
(fcriiiiiiiitotl and giTen off an 
eif?lit-celled promycelium ; spori- 
diaiire heinnubjiiintcd iu whorls. 



306 USTILAGINEAE. 

T. buUatum Scliroet. (U.S. America). The ovaries of Panimm 
Crus-galli are transformed by this fungus into spherical tumour- 
like bodies, which project from the otherwise unchanged flower 
and enclose the black spore- masses. The spore-balls consist of 
hundreds of spores which, Brefeld says, germinate in water in 
the following year. Each produces one, two, or three two- 
celled promycelia, which give off terminal spindle-shaped conidia; 
these sprout in nutritive solutions and ultimately form aerial 
conidia. 

T. Cocconii Mor. In leaves of Carex recurva in North Ital}'. 
T. penicillariae Bref. On Penicillaria spicata from Simla. 
T. cenchri Bref. On Cenchnis echinatus. 

Tilletia. 

Spores formed from hyphae, which swell up in a gelatinous 
manner. Conidia spindle-shaped or filamentous, and produced 
in whorls from the extremity of a non-septate promyceliinn ; 
they are developed only in air and generally fuse in pairs 
before being detached from the promycelium. 

Tilletia tritici (Byerk.) {T. caries Tul.) (Britain and U.S. 
America). Smut, stink-brand or stinking-smut of wheat. 

This constitutes one of the most destructive smuts of wheat- 
grain, not only destroying the grains actually attacked, but the 
black spores cause such damage to the remainder, when threshed 
or ground, that it is useless for bread-making. The presence 
of this fungus is most obnoxious from its strong odour of herring- 
brine or trimethylamin, hence the name stinking-smut or stink- 
brand. The smut also possesses poisonous properties which make 
flour contaminated with it dangerous to human beings, and the 
straw or chaff injurious to cattle. 

Certain diseases are produced in animals by the consumption of smut- 
fungi with food. The effects of each species of smut have not as yet been 
closel}'' investigated, but Tilletia tritici seems to be one of the chief causes 
of trouble. The following are also suspicious : Ustilago maydis and the 
various species of Ustilago which attack oats, barley, wheat, and grasses. 
The symptoms in the few cases of disease observed do not agree very 
closely. A paralyzing effect on the centres of deglutition and the spinal 
cord seems to be regularly jiresent. As a result one generally finds a 
continuous chewing movement of the jaws, and a flow of saliva, also 
lameness, staggering, and falling. Cattle, sheep, swine, and horses are all 
liable to attack. 



TILLETIA. 



3o; 



The black spore-powder is developed as an evil-sinelling mass 
in the ovaries of the host, which are completely destroyed except 
the outer coats. As a rule every grain in an ear is attacked. 
The smut is at tirst oily or greasy, but gradually dries up to 
form a hard stonv mass enclosetl in the frnit-fdumes ami 





Fio. 167.— TilUlUi liitici. A, Twu spores genninatcd in 
moist air; a short promycclimn is dcvcloiicJ, nuil Ix-'ars a 
crown of conidia (sporidia), sevcnil of wliich have fused in 
pairs. Fushion of conidi.i, gcrniination, and development of 
a secondary conidiiini, C, are also shown. S, Two spores 
gei-miuated in water with proniyeelia which elonjf-.ite till the 
water surface is re;iehed, where they form sporidia ; the 
promycelia are .septate and the plasma i)a8ses over into the 
hui. Iti,;. -fdUtw tytttci. voiuiKer cells, (v. Tiibeuf del.) 
Stud-iii'i-iMut of U heat. E.ir of 
wheat with smut-grains indi- 
cated black. The isolated spike- 
let contains two smut-(^.iins, 
which, as Well as the isolated 
examples, show tissures in the 
original ovary wall. <tne smut- 
grain in section shows the in- 
terior filled with lilack spores, 
but the ovary wall still intact, 
(v. Tut)euf del.) 

])ak'S. The spores, theiet'oic, do imi escujii' as (hisl mi iIh- 
ticld, Init remain in the heads and are garnered with the crop. 
Smutty ears are easily distinguishfd <>n the field by tiu'ir 
stiff erect position towards harvcst-tiiut', as inmpan'd with tbf 
more or less nodding healthy ears: their florets also lie more 
away from the axis of the ear, the ehalf-glumes are more spread 



308 USTILAGINEAE. 

out, and the grains are somewhat compressed. In earlier 
stages of development the diseased ears are less easily dis- 
tinguished, but they grow more rapidly than the normal, their 
ovaries are earlier formed, and have a dark greenish-brown 
colour. According to Kiihn,^ the ears in their earlier stages, 
as they emerge from the leaf-sheath, possess abnormally thickened 
seed-coats, especially towards the apex, while in section they show 
a dark-green colour. He also found the grains to be replaced by 
a white and easily detachable mass of fine mycelium. Spores 
are formed as swellings on the ends of the sporogenous hyphae, 
and into these the plasma-contents of the hyphae pass over. The 
mature spores are dark-grey and spherical, with netted markings 
on the episporium. They germinate in water, and produce a 
promycelium of varying length. The conidia arise as a whorl 
of thread-like branches on the end of the promycelium, and into 
them all the protoplasm passes over, while the promycelium, 
after being cut off by a cross septum, disappears, leaving the 
conidia as isolated bodies (Fig. 167). The conidia become united 
in pairs, frequently before isolation. After fusion comes germina- 
tion, and the emission of a filament from the end of which 
sickle-shaped conidia are abjointed. Kiihn states that these 
conidia, as well as the whorled primary conidia, if placed in a 
damp atmosphere, can give rise to a hypha capable of infection. 
In water, however, the hyphae continue to grow longer, the 
plasma from the older parts passing over to the younger, and 
no conidia are formed (Fig. 167). 

The conidia which remain unpaired were found by Brefeld to 
behave similarly to those which pair, except that the resulting 
germ-tubes and conidia remained smaller. Spores refuse to 
germinate in nutritive solutions. Conidia grown in water 
cultures and placed afterwards in nutritive solutions, give off 
a fine mycelium, from wdiich short, lateral, aerial branches 
become cut off by septa, and devote their contents to the pro- 
duction of a few sickle- shaped conidia ; these are easily detached, 
and produce a mycelium capable of giving off further conidia 
in a manner similar to that just described. 

The investigations of Brefeld have also given the interesting 
result that hyphae which produce conidia may also give rise 
to spore-like bodies. The hyphae, after growth in length has 

' Kiihn, Dh KranMititen d. KuHurgeivdchsc, 1858. 



TILLKTIA. 309 

ceased, begin to thicken, at first equally, then more at some 
places than others, so that they hecome nodose or rosary-like, 
with swellings at irregular intervals. The spores originate in 
the swellings, and between them are formed cross-septa whicli 
split and bring about isolation of the spores. 

Kiihn's experiments on infection are of considerable interest. 
He investigated the germination of this and other smut-fungi, 
cultivating many of them in his garden at Halle, and published 
his results as early as 1858.^ In his artificial infections he 
dusted seedlings with spores of Tilhtia, and investigated the 
different parts of them microscopically. Sections showed him 
that the germ-tubes penetrate direct through the walls into 
the epidermal cells, and always in the neighbourhood of the 
lowest nodes. Thence the mycelium grows upwards with the 
lengthening plant, especially through the pith, and the plasma 
of the older mycelium passes onwards into younger parts. In 
this way the hyphae, without greatly disturbing the growth of 
the wheat-seedlings, reach the ovaries, and with the formation 
of spores begin the work of destruction. 

Kiihn was also able to demonstrate that both germinating 
sporidia and conidia are capable of infection, and that, where 
many had infected the same plant, so much mycelium could be 
produced that death of the host ensued. According to the 
same authority, the fungus attacks spring wheat more than 
winter wheat, and the common forms (Trificum scitivitm and 
2\ tiirijklam) with nearly allied varieties, more than " s]M'lt " 
{Triticum sj)clta). 

As a preventive measure against Tilldia, the experiments of 
Kellermann, Swingle, Kirchner, and others, lead them tn recom- 
mend Jensen's method of placing the .seed in hot water innnedi- 
ately before sowing. (See Chap. VI.) 

Tilletia laevis Kidm. (I'.S. .Vmerica.) Tliis is another stink- 
ing smuL (if wheat similar li> 7'. tritiri, except that its spun-s 
lia\f perfectly smootii coats. 

T. controversa Kidin. Found in grains of Tritimm rrpnis 
(cftueh-grass) as well as '/'/•. rn/i/ni-i and 7V. if/inniiin. The 
spores are distinguished fmui those of '/'. frifiri by the hiuher 
rid'j'"^ and widei- iiiesli<'s on the episporitini. 'i'hr mycelium 

' I'ri-viouM t<» Kuliii, I'revo.sl .likI 'Iii1,imii' ImiI in ls."i;{ liiirinl mil f\|>i'riiiifiitM ; 
iil.-to (•luichL-n ill I"**!. 



310 USTILAGINEAE. 

perennates in the rhizomes. The spores, according to Brefeld, 
germinate in water after a resting period of two years ; in 
two years more they lose their capacity for germination. 

T. secalis (Cord.) ^ is epidemic and destructive in ovaries of 
JSecalr a real r. 

T. decipiens Pers. (Britain). In fruits of Acjrostis vulgaris 
and A. stolonifera. Schroeter says the plants remain stunted, 
Brefeld states that spores germinate in water after a resting- 
period of three years, and lose their capacity for germination 
in the following year. 

T. lolii Auersw. frequents the ovaries of cultivated Lolimn 
jjerennc, and of Z. tcmvlaitum (darnel-grass). 

T. hordei Korii. occurs in grain of Hordeum fragile and H. murinum in 
Per-sia. 

T. separata (Kinize). In grain of Apera Spica-venti. 

T. calospora Pass. In grain of Andropogon agrestis in Italy. 

T. Rauwenhoffii Fisch. In grain of Holcus lanatus in Belgium. 

T. olida (Eiess.) forms stripes on the leaves of Brachypodium sylvaticum 
and B. pinnatv/iii. 

T. sesleriae Juel forms similar stripes on leaves of Sesleria coeridea. 

T. striiformis (Westend.) occurs on leaves, leaf-sheaths, and stalks of 
Alopecunis, Anthoxantlntm, Milium, Holcus, Arrhenatherum, Briza, Poa, 
Dactylis, Festuca, Bromus, Agrostis, Lolium, etc. (Britain and U.S. America). 

T. calamagrostidis Fuck. On leaves of Calamagrostis epigaea, C. Halleriana 
and Triticum repens. 

T. epiphylla Berk, et Br. Stink-brand of Australian maize. 

T. Fischeri Karst. In fruits of Carex canescens in Finland. 

T. arctica Eostr. On leaves and stalks of Carex f estiva in Fiiimark. 

T. thlaspeos Beck. In fruit of Thla^pi alpestre. 

T. zonata Bref. On Sporoholus ligidaris from Quito. 

T. (?) glomerulata Cocc. et Mor. occurs in Italy on leaves of Cynodon 
Dactylon, Plantago lanreolata, and Medicago. 

T. sphagni Nawaschin- was once regarded as a second form of s])ore of 
Sphagnum. 

T. oryzae Pat. The fungus to which this name was given forms 
sclerotia in the grain of Oryza sativa (Rice) in Japan. 

Brefeld^ found that dark spores are given off from the surface of the 
sclerotia. These spores, on germination in nutritive solution, produced a 
septate mycelium which, in dilute solutions, gave off pear-shaped coloui'- 

' Kiilm, Botan. Zeitionj, 1876, p. 470. Cohn, Jahrbuch d. Schles. Ges. f. 
vaterland. K^dtur, 1876. Niessl, Hedu-igia, 1876. 

- Navvaschin, Uiiher die Brandkrankhtit d. Torfmoone, 1893 ; and Melanges 
hiologiques, t. xiii., liv. 3, 1893. 

'^ Botan. Gentralhlatt, i.xv., 189G, p. 97. 



TILLETIA. 311 

less coiiidia incapable of geniiiiiatinii. When the nutritive sohition was 
frequently renewed, the niyceliuni grew vigoroush- and formed a .selerotium- 
like body, from which the dark spores were laterally abjointed and set 
free. On this account Brefeld founded a group with the generic name of 
Ustilaginoidea ; it includes this species as Ustilaginoidea oryzae and an- 
other similar one on Setaria Crus-Ardeae he calls Ust. setariae. The group 
has affinities with the Ustilagineae and Ascomycetes like Claviceps, and 
Brefeld sees in it a connecting link between the two families. 
Several other American species of Tilletia have been recorded. 

Neovossia. 

Characters similar to Tllldia, except that the coiiidia produced 
on gerininatiou of the spores do not coalesce. (Jonidia sown 
in nutritive solutions produce a mycelium with two kinds of 
secondary coiiidia. 

N. moliniae Koniike. The black spore-powder is developed 
in enlarged cjvaries of Molinia cocrulea. The smooth ovoid 
spores are eiiclo.sed in a transparent mantle, and have a hyaline 
tail-like appendage. Each spore is produced at the end of a 
hyphal filament, which remains attached after the spore-mass is 
freed and forms the appendage. The spores germinate in water 
at once, and send up a simple aerial proinyceliuin, on the apex 
of which a crown of many needle-like coiiidia are produced. 
Septation of the promycelia may take place if they become very 
long, the protoplasm passing into the apical segments and leaving 
the basal empty, as in Tilletia. liranching of the promycelia 
may also occur. The coiiidia im being shed give off sickle- 
shaped secondary conidia. In nutritive solutions, however, the 
Coiiidia produce a mycelium from which either sickle-shaped or 
needle-shaped conidia may be given oH'. the hiUci' however never 
as a crown or circlet. 

N. Barclayana Href. In tin- fruits of I'lnniio'tuia trijtufHin in .Sjuda. 
(This is lint svMDnynious with I'stifni/o pt'itiuneti Habh.). 

N. {'.) bambusae liief. In fruits of bamboo from Brazil. 

Entyloma. 

.Mycelium intercellular and never gelatinous. The spores 
are of InlfMcalary origin, and arise here and there on any jiart 
of the inyecliuiii. 'i'he spore-clusters ajjpear externally as 
spots, and till* sjtores in-Mtr leave the Imst. The spores on 



312 



USTILAGINEAE. 



germination produce a thread-like promycelium bearing apical 
conidia, wliicli conjugate in pairs before emerging from the 
host-tissues. 

The following species form conidia on the host-plant : 

Entyloma serotinum Schroet. occurs on leaves of Symphytum tuberosum, 
S. officinalis, and Bora(jo officinalis. 

E. canescens Schroet. On Myosotis (Britain). 
E. fuscum .Schroet. On Papaver Rhoeas and /'. Argemone. 
E. bicolor 'Ao\)i. On Papaver Rhoeas and P. duhium (Britain). 
E. ranunculi (Bon.) forms white spots on species of Ranunculus. Tufts 

of hypbae emerge from the storaata and 
form conidia, which on germination again 
give off conidia.i (Britain.) 

E. corydalis De Bary on Corydalis 
cava and C. solida. 

E. heloscladii Magn. on Heloscladium 
nodifiorum. 

These do not produce conidia on 
the host-plant : 

E. thalictri Schroet. on Thcdictrum 
minus (U.S. America). 

E. verruculosum Pass, on Ranunculus 
lanuginosus. 

E. Fischeri Tlium. on Stenactis bellidi- 
Hora. 

E. chrysosplenii (Berk, et Br.) on 
Chrysosplenium alternifolium (Britain). 

E. linariae Schroet. on Linaria vulgaris 
(U.S. America). 

E. picridis Rostr. on Picris hieracoides. 

E. eryngii(Corda) on Eryngiwn planum 
and E. campestre. 
E. calendulae (Oudem.) on Calendula, Hieracium, Arnoseris, Arnica, 
Bellidiastrum, etc. (Britain) (Fig. 168). 

E. crastophilum Sacc. on Poa and Dactylis in Italy. 

The following produce gall-like swellings : 

E. microsporum (Ung.) {E. Ungerianum De Bai\y) (Britain and 
U.S. America). On Ranunculus repens, R. hulbosus, and R. Ficaria 
(Fig. 168). 

E. Aschersonii (Ule) on roots of HcUchrysum arenarium (Fig. 169). 

E. Magnusii (L"le) on roots of Gnaphalium uliginosum and G. luteo-alhum 
(Fig. 170). 




Fig. 168. — Entyloma calendulae. a, My- 
celial filament, with two young resting- 
spores. b, Resting-.spore germinating ; 
the anterioi- pair of primarj' conidia 
shows conjugation or fusion at the base. 

Entyloma microsporum. c. Germinat- 
ing resting-spore ; four primary conidia 
fusing in pairs at their apices, d, The 
same specimen seven hours later ; com- 
mencement of abjunction of a secondary 
sporidium on each pair. (After De 
Bary.) 



' H. M. Ward, PhilosopJi. transactions of Boi/ctl Sac. London, Vol. 178, 1889. 



ENTYLUMA. 



313 



Still to mention are : 

E. EUissi Halst., known as "' wliite smut. 
{Spinacia ohracea), discolouring the leaves. 

E. ossifragi Rostr. on yarthecium ossifragum in Denmark. 
E. catenulatum Kostr. on Aira caespitosa in Denmark. 



It inliabits .spinach 



Fig. 1(59. — Entyloma Asclieraonii. Germin- 
ated spore with septate promyeeliuiu ; one 
promycelial branch remains rudiment.iry, 
the uther (to left) has produced two br.uiches, 
one of wliich has elongated and hears a coni- 
dium. (.\fter Woronin.) 




Fi(i. I'0. — h'iilylo,u'i Moiinuiii. Germin- 
ated spores ; the promyceliuni of one sliows 
a wliorl of three branches with apices 
elongating to fona germ-tubes; tlie other 
shows two, out of three, germ-tiil)es giving 
off l)ranchcd si)oridia (conidia). (After 
Woniuin.) 



E. leproidum Trab.'- [tJedomycex Ifproides (Sacc.)]. Disea.sed beet-root 
exhiltits irn^ulai- <)Ut<,'rowths, whidi enclose .spaces tilled with the brown 
spore-jxtwder of this fungus. 

E. nympheae (Cunningham) Sftch.' nn various species of A'i/»ip/ic<i in 
America, Afiica, and Europe. 



Melanotaenium.^ 

Spore.s unicellular in iiatchcs <pn an intcrcfllular niycflimu 
lyin;< (l»,'i-li in llie host-plaiil : lln'V lia\f a thick dark luiwu 

' HaJHted, Xfir Jcrx, !/ A;iric. Kx]»r. Sfafiou Hxillflin, No. 7t>, iSJKt. 
'-'Iralnit, " Siir luie Ustilagintf para.siti- ib- la Betterave." Cotiipt. n inl. 
cxviii., 1X94. 

'Setcliell, lioliiiiirul (lit'.elli , 1S'.I4, p. l.SS(\Mtli illu.st ratioim). 

■"Sc-hroetLT, Kriz/ifDi/fuii. Flora r, Sr/tleiim. W'ovouiu. St iirU'riilnrij (ientlt, ISSM. 



314 



USTILAGINEAE. 



epispore, and the clusters appear black or leaden-grey. Ger- 

juination as in Enti/lomn. 

Melanotaenium endogenum (linger) (Britain). This is 

found on Galium Mollugu and G. verum. The mycelium 

permeates the whole intercellular system of the host, and is 

nourished by large tufted haustoria. 
The host-plants remain small, with 
shortened internodes, shrunk leaves, 
and undeveloped flowers. The 
spores occur in patches in de- 
formed flowers, and on leaves and 
internodes. They are formed in 
summer, and by autumn are capable 
of germination in water ; AVoronin 
could not .keep them alive over 
winter. On germination a bifur- 
cate promycelium is produced, one 
branch of which remains rudimen- 
tary, while the other grows on, 
and, if long, becomes divided by 
cross-septa. At its apex, a number 

of conidia arise, and, after many of them have fused in pairs, 

they germinate directly to a septate filament into which the 

plasma passes over (Fig. 171). 

Mel. caulium (Schneider) causes the stem of Linaria vulgaris to swell 
11]) like a quill. 

Mel. cingens (Beck.) on Linaria genistifolia. According to Brefeld, 
this species onlj germinates after resting for four years, whereas .Juel 
easily caused Mel. ccmliuin to do so after a short rest. 




Fig. 171. — Melanotaenium endogenum. 
Germinating spores. One has already 
produced a promycellvim with a whorl of 
five branches, of which two have fused. 
(After VV'oronln.) 



Urocystis, 

Spores massed into balls, consisting of several spores sur- 
rounded by smaller companion-cells incapable of germination. 
The central spores are clearly distinguished from the others 
by their larger size, darker colour, and thicker coat. The balls 
of spores are developed inside coils of hyphae, which become 
entwined together and swell up in a gelatinous manner. The 
central spores on germination give rise to a promycelium, with 
terminal conidia which do not as a rule fuse in pairs, but grow 
out directly into mycelia. 



UROCYSTIS. 



315 



Urocystis occulta (Wallr.). (Britain and I'.S. America.) This 
species is cuiuuimh un the hauhns, leaves, leaf-sheaths, and less 
commonly on tioral parts of Secalr nrmli' (rye). It causes the 




Kli.. I'll. — iriK-iittiii DCcuUtt nil Kyc. 'I'lic ciiiM iiro ittuiituJ, ami tlio HiK)it'- 
|M,wclcT uiiiorxcH from lont^tuiiiiiul flsiHiii'cH in lliu ujijict part <if tliu stoiiiN. 
(V. Tubiuf phot.) 

formation of ;^Mcy stripes, frnm wiiich a lilatk spore-powder 
escapes. 'I'lic haidms become disea.sed and snmtty, iherehy 
])rt'vcnlinL; drvt-lopment of the ear, whieh n-Miains sttintt'd and 



316 USTILAGINEAE. 

empty (Fig. 172). Spore-formation causes the parenchyma of 
the stem to be destroyed in strips, along which rupture takes 
place, and the haulm, losing its rigidity, falls over. The balls 
of spores consist of one or two smooth spores enclosed by 
companion -cells. Germination takes place easily in water, and 
a circle of cylindrical conidia are produced from the end of 
each promycelium. The conidia, without becoming detached, 
give off a lateral germ-tube. The mycelium does not hibernate. 

While this smut does not occur on cereals so commonly as 
species of Ustilago and Tilhtia, still it may sometimes cause 
severe loss. Treatment of seed by Jensen's hot-water method, 
or by a copper sulphate steep, may be resorted to, but the 
results have not as yet been always successful. 

The only other smut of rye is Ustilago sccalis in the grain, 
and it is only rarely found. Winter, however, considers rye 
amongst the host-plants of Urocystis agroj^yri. 

Urocystis agropyri (Freiiss.) (Britain and U.S. America). Leaves and 
haulms of Triticum repens, Arrhenatherum elatius, Festuca rubra, and 
Bromus inermis are the habitat of this species. 

U. festucae. Another species distinguished by Ule on Festuca. 

U. Ulei Magn. In leaves, more rarely in inflorescences, of Poa pratensis. 

U. luzulae Schroet. On leaves of Luzula pilosa. 

U. colchici (Schlecht.). On leaves of Colchicum autumnalc, 
Muscari comosum, M. racemosum, Paris quadrifolia, and Scilla 
hifolia. (Britain and U.S. America.) 

U. cepulae Frost.^ (U.S. America). Onion-smut. This 
frequents the green leaves and subterranean scales, producing 
pustules, which break when mature and allow the black spore- 
powder to escape. 

U. ornithogali Korn. frequents leaves of Ornithogalum %mihellatum. 

U. gladioli (Req.) is found in tubers and stems of Gladiolus (Britain). 

U. anemones (Pers.). (Britain and U.S. America.) Anemone- 
smut. This may be found in leaves or stems of many 
Ranunculaceae: Anemone Hepatica, A. neviorosa, A. ranunculoides, 
Pulsatilla alinna, P. vernalis, P. Pennsylvanica, P. acuiiloha, P. 
haldensis, etc. ; also on Atragene alpina, Aconitum Leucoctonum, 
Actaea spicata, Hellehorus viridis, H. niger, Ranunculus Ficaria, 
B. bulbosus, B. repens, B. sardous, Eranthis hiemalis. Brefeld 
says the spores germinate in water, after resting for half-a-year. 

1 R. Thaxter. Report of Connectmit Agric. Exper. Station for 1889. 



UROCYSTIS. 



31 ■ 



U. Leimbachii lOertel.) causes glolmlar swellings uf the 
stem-base of Adonis aestivalis at Jena (Fig. 173). Patouillaid 
regards this species as a form of II. anemones, differing somewiiat 
on account of its underground habitat. 

U. sorosporioides Korn. (Britain). On PuhatilUi alpina, Thalic- 
trum minus, and T. foetidum, forming pustules and .swellings. 




Fio. 173. — A, Urocy»tii anemones on Hellelx)re. Spore-patches on Htnlk and 
mid-jib. (v. Tubeuf del. ; specimen from llerr Sclinabl of .Munich.) 

B, Urocystis Ltimliachii (U. aneiuonei), cjiusiug Mwelling at husu of .stem of AdonU 
aettivalU. (v. Tubeuf del.; specimen from Prof. Stahl of Jena.) 



U. violae (Sow.). (Britain and U.S. America.) The det'orma- 
tiiius induced by this brand are not uncommon on Viola 
odonda in gardens, also on V. tricolor, V. badensi.f, and V. 
hirfa. Its presence is shown externally by the marked thick- 
ening and malformation of leaf-i)etioles, runners, leaves, and 
fruit-stalks (Fig. 174). The swellings e.\tend round the wiiole 
stem, and form pustular outgrowths on the leaves ; the black 
spore-ma.sses api)ear after rupture of the epidermis. The 
llower may develop iKuiually although uilier organs aie diseased. 
Ill a ease fnjin the ganUni of I'lof llaitig, a Ihtwer-buil 
unfolded prematurely in the autumn, its stalk was vi-rv 
much deformeil, the llower itself was somewhat stunteil, vet 



318 



USTILAGINEAE. 



the plant as a whole did not seem to be much affected. On 
the other hand, a case was observed near Munich where a 
large plot of violets was completely killed out in a few years 
by this fungus. 

The anatomical changes induced on Viola odorata were 
investigated by Wakker^ with the following results : a swelling 
of the stems, leaves, and flower-stalks occurred, often accom- 
panied by considerable twisting and rupture of the epidermis ; 
these changes were not caused by any enlargement of cells, but 




Fig. 174. — Urocy»tis vioLae on Viola. Smiit-pustules are present on leaf-stalks 
and fruit-stalks, accompanied by malformation, (v. Tubeuf phot.) 



the cambium remained longer active in the stem, and a secondary 
division of rind-parenchyma or mesophyll could be observed, 
along with a disappearance of intercellular spaces ; accessory 
vascular bundles were formed, but the secondary vessels remained 
incompletely developed. In short, new growth occurred, not 
in the earlier stages of the host's life, but in the adult. 
Especially noteworthy is the formation of a small-celled tissue 
resulting from cell-division in the rind-parenchyma and the 
mesophyll ; this serves as a nutritive tissue for the fungus, 

1 Wakker, Frm;/.s/i^-/;H".s Jahrhurh, 1892. 



uRocYSTis. 3 1 y 

and is *lestroyed during spore-formation, so that the balls of 
spores are found in large cavities in the host-tissue. 

In the spore-masses the enveloping companion-cells are more 
transparent than the spores proper. The latter germinate^ easily 
in water, and produce promycelia which grow towards the air. 
()n the extremities of these several conidia arise, and, without 
becoming detached, proceed at once to give off short cunidid- 
phores ^ with terminal conidia. As this process is repeated 
indefinitely, chains of conidia are formed. Fusion of conidia 
never occurs. 

U. Kmetiana Magn. Magnus- describes this as destroying 
and tilling with l)lack spore-powder the ovaries of Viola tricohn- 
{rnr. i(rrrn>;is). 

U. filipendula Fuck, oc-curs particul:u-ly on petioles and leaf-ribs of 
J^p/r"t-'i Filippiidaln. Brefeld found the spores germinating after a year. 

U. (?) italica (Sacc. et Speg.). In seed of Castanea vesra. 

U. purpurea Hazsl. Ovaries of Dianthus deltoides and J), prolifera in 
Hungary. 

U. (?) coralloides Rostr. In roots of Turritis glabra in Denmark. 

U. orobanches (Fr.). In roots of Orohanche. 

U. ( ') monotropae (Fr.) In roots and stems of Monotvopa in Belgium. 

U. Johansonii {U. Junri. Lag.). In leaves of Junrus filifonnis in 
Switzerland. 

Tuburcinia. 

Spores forming lialls as in i'rucijstk, but all are equally 
ca})able of germination. The spore-aggregations form large or 
small, slightly thickened spots and crusts, which do not cause 
very marked deformation of the host. Germination result.s, as 
in TilUtiii, in the formation of a promycelium ])earing a tuft 
(if cniiidia at one end. \\ bite conidia are also produced fmui 
tliL' iiivi-.'liiiiii (III tbi' linst-])lant. 

Tuburcinia trientalis (JJerk. et, Jir.)'' (llriiain and I'.S. 
America). I'lants of Trientalis europa£a attacked by this fungus 
are crtnspicuous in early summer by their swollen dark-cob »uri'd 
stems and their smaller lighter leaves, which fall yjrematuiely. 
The conifUa ajipear as a white moubblike coating on the lowei- 

' I'rillieux, JSii//rf. ,lr la Sor. hofnn. d- Frniir,, ISSO; iiii.l IJrefel.l (A..-, rif. , 
lieft XII. 

'-'Miij^nuH, Xaturforiirh. Fr. d. I'ror. /iraiidnihiirii, \\\i. 

•'Woronin, Stnrktidtcnj . natnrforncli. CtiKtll., IHHI. I'hiti's 1., II., 111. 



320 USTILAGINEAE. 

side of the leaf. The black spore-masses are formed in the 
riiul-parenchyma, and sometimes in the pith ; they are set free 
by rupture of the epidermis. 

In autumn the symptoms are different. The plants appear 
normally developed, and have no coating of conidia ; dark 
swollen spots, however, appear on the leaves and leaf-petioles, 
in consequence of the massing of black spore-balls in the par- 
enchyma under the epidermis. 

The summer mycelium consists of colourless irregularly 
branched and slightly septate hyphae occupying the intercellular 





Fig. 175. —Ttiburcinia trieatalis. Spore- Fig. 176. — Apex of an isolated promy- 

mass germinating ; several promycelia have celium from Fig. 175 ; it carries a whorl of 

been produced and are proceeding to form branches, some of which have fused in pairs ; 

whorls of branches. (After Woronin.) all are developing conidia. (After Woronin.) 

spaces of the pith and rind-parenchyma, also the vessels. The 
hyphae apply themselves closely to the cell- walls, and certain 
short branched hyphae actually penetrate into the cells. The 
spore-masses are developed from delicate branched multiseptate 
filaments of the vegetative mycelium. They begin as two or 
three little cells round which a coil of hyphae is formed ; the 
central cells, increasing in number and size, become a ball of 
dark smooth-coated spores, while the enveloping coil of hyphae 
disappears. 

The spores germinate during the same autumn, frequently 
in the position of their formation. A promycelium is first 
formed, and on its extremity a circlet of conidia arises ; there- 



TUBURCINIA. 321 

after the promycelium becomes divided l)y cross-septa in its 
upper part, and the conidia too are frequently divided by one 
or two septa. The two proiuycelial cells become detached, 
while the conidia begin to fuse together l»y means of out- 
growths near their base ; thereafter each conidium gives 
out a secondary conidium, into which the plasma-contents 
pass over. A similar formati<jn of secondary conidia may take 
place without previous fusion of the primary conidia. Tlie 
conidia fall apart, and they, as well as the upper pnjmycelial 
cells there) )y left isolated, grow out as hyphae. It must be 
these hyphae which infect the rudimentary shoots of Trkntalis 
when they are already partially formed for next year. The 
resulting mycelium permeates the shoots in the following spring, 
and branches of it emerge through the stomata, or pass between 
the epidermal cells and break the cuticle, to grow up either at 
once as conidiophores, or to form on the surface of the leaf a 
web from which conidiophores arise. The pear-shaped conidia 
are attached by their broader side, and easily fall off", leaving 
the conidiuphures free to produce new conidia. The conidia 
are capable of immediate germination, and may produce a 
lateral germ-tube, which grows directly upwards, and gives oft" 
secondary conidia ; or the conidia themselves grow out into 
hyphae, capable, as Woronin proved experimentally, of carrying 
out infection. Such hyphae penetrate between the walls of 
adjacent epidermal cells, and give rise tu a mycelium which 
spreads in a centrifugal direction and forms tiie .•^puri-- 
masses. 

This .same fungus has also Ijetm found on KupJirdsin lutrti 
and Paris fiuadrifol'M. On Euphrasia, according to Winter, 
it causes formation of large swellings, accumpauied l»y consider- 
able ilcformation of leaf ami stem. 

T. primulicola (.Magn.) KiUin.' (Ihitain). This smut attacks 
tlowers of I'rimuUi acaulis, P. tt(ficinalis, P. i/atior, P. farinosn. 
In cases described in Germany, the bltjoms were generally 
attacked in the filaments or connective of the stamens, but also 
in the anthers, the ovaries, i)istil, stigma, and sometimes in the 
calyx-tube ; wiiile the whole llower-hrad was more or less 
discoloured by the black spore-dust. Tlie mycelium permeates 

' MiigiiUH, liotan. Vnrtin lirandfuhnrij, 187H. Kiilm, " clic Kiitwiikilimgw- 
gCHcli. il. IViinelhniiKlcH," Xfifiir/nrtrli. '(itntl/. -.u IlitU< , lSi»'_'. 

X 



322 USTILAGINEAE. 

the whole host and hibernates in the root-stock. The spores 
are developed from the ends of hyphae in the host-tissue, and 
are either isolated or joined into packets. They germinate 
easily in water, and produce either a fine germ-tube, or a 
thick promycelium with four oblong conidia on its apex. The 
€onidia are easily detached, and either develop to fine hyphae, 
or give off secondary conidia. Germination on the whole is 
similar to that of T. trientalis. Conidia may be also produced 
directly on the host-plant ; these were first described by Kiihn, 
who named them Pai2Jcdo2Jsis Irmischiae ; later, however, he 
succeeded in infecting plants of Primula with the conidia, and 
in proving their relationship to this Tuhurcinia. 
T. Cesatii Sorok. occurs on geraniums in Russia. 

Here, according to Setchell, the following American genera should be 
placed : 

Burillia : B. pustulata on Sagittaria. 
Cornuella : C. lemnae on Lemna polyrhiza. 



Doassansia. 

Spore-masses consisting of numerous spores capable of ger- 
mination, enclosed in a layer of sterile cells. The latter are 
most conspicuous in the species frequenting aquatic plants, and 
are filled with air, — Brefeld regards them as swimming-organs. 
The spore-masses lie in groups embedded in the host-plant. 
The species inhabit plants with an aquatic or moist habitat, 
and produce on them leaf-spots with black pustules. 

Fisch ^ investigated the life-history of Doassansia sagittariae. 
He found an intercellular mycelium which, inside the stomata, 
formed sporocarps, consisting of sclerotium-like coils of hyphae 
enclosing several cells which form spores. The spores on germina- 
tion give rise to promycelia, which produce sporidia in a manner 
similar to Entyloma. The sporidia easily germinate in water, 
and can immediately infect young leaves. The germ-tubes 
creep on the surface of leaves, and attaching themselves by 
an adhesion- disc over the wall between two adjacent epidermal 
cells, they penetrate this wall. The hypha, while passing 

^ C. Fisch., Ber. d. dtiitsch. hotan. GeselL, 1884, p. 405. Cornu, Annal. d. sci. 
natur. xv. , 1883. Setchell (Botanical Gazette, 1894) records the American 
species and comments on tliein. 



DOASSANSIA, 323 

thioiiLih the wall, remains thin, but on eniemin'' into an inter- 
cellular space it soon thickens and branches into a mycelium. 
Infection results in the appearance of yellow spots, due to 
rapid destruction of the chlorophyll and death of cell-contents. 
Experiments in germination have been carried out by Setchell 
and I'.rrf.-M.^ 

Doassansia sagittariae (West.) (Britain and U.S. America), 
in It-avt's of Satjittaria. The spores, according to Brefeld, 
germinate in water, after hibernation. They produce unicellular 
promyceliu with a terminal tuft of more or less spindle-shaped 
conidia, which at once begin to sprout and fall off. On the 
surface of a nutritive solution they continue to sprout yeast- 
like, and form close mouldy coatings. {Doassansia is the only 
genus of the Tilletiae in which Brefeld found yeast-like sprout- 
ing of conidia.) 

D. alismatis (Xees) (Britain and U.S. America). This 
iniiabits leaves of Alisma Plantayo and A. natans, producing 
knotty swellings. The .spores are enclosed in a layer of com- 
pani«jn-cells containing air, whereby the masses swim on water. 
( )n the promycelium the conidia arise from tufts of conidio- 
phores ; they fuse in pairs^ and secondary conidia are developed 
fioiii enr-]\ pair or even from single conidia. 

D. Niesslii (de Toni) forms small spots on leaves of J!ii(o- 
iims nrnUllatv.s. The spores are surrounded by companion-cells 
containing air. They germinate before leaving the spore-patch, 
and produce 'conidia, even secondary conidia, before rupture of 
the host-epidermis takes place. Brefeld describes the spores 
as germinating in water to form a very short promycelium 
with short thick conidia which fuse in pairs and give off larger 
secondary conidia from their apices. In nutritive solution 
conidia are developed, which give off septate filaments whence 
further conidia arise. Aerial conidia are ultimately develoj)ed. 

Magnus found that the spores of I), alismatin, D. ^less/ii, 
and other s})ecies germinated at once on reaching maturity. 
Hiefeld, however, found tliat this took place only after they 
had lain over winter. It may be that here, as with some 
higher i)lants (*.//. J'iniis (Amhra), there is an immediate 
capability of germination, but also a deferred, tlie latter retjuiring 

' Sctcliell, Aiinii/.'i u/ Jiutaiii/, VI., IV.CJ. Itufelil, Sihimtiuljiilit', lltfl \ii., 



324 



USTILAGINEAE. 



to be preceded by a considerable resting-period, during which 
germination will not take place. 

D. Martianoffiana (Tliiiui.). In leaves of Potamogeton 'Jtataas and P. 
graminevti. 

D. occulta (Hoffm.). In fruits of species of Potamogeton. 

D. intermedia (Setcli.). An American species found on leaves of 
Sagitturla van'(d)}I)s. 

D. comari (Berk.). In leaves of Gomarum paUcstre in Britain. 

D. limosellae (Kunze.). In flowers of Limosella aquatica. 

D. hottoniae (Rostr.). In leaves of Hottonia palustris in Denmark. 

Thecaphora. 

Spores, large, spherical, and inseparably united into packets 
of several spores. Germination results in the formation of a 




Fig. 177. — Thecaphora kyaUna. Pliiricelln- 
lar spore, with two cells (spores) germinating. 
(After Woronin.) 




Fig. 178. — Sorosporium saponariae (var. 
Lychnidis dioicae.) Mature spore-mass, and 
spores germinating. (After Woronin.) 



promycelium from the apex of which a single conidium is 
produced. 

Thecaphora lathyri Klihn. Spore-balls formed in the seeds 
of Lathyrus ^;?r^^!fws^s, and escaping as a brown powder on 
dehiscence of the pods. The spores germinate in water with 
formation of a promycelium bearing a single apical conidium, 
which produces a hypha, but never secondary conidia. In 
nutritive solutions the spores produce a mycelium from which 
conidia are continuously given off. 

Th. hyalina Fingerh. (Britain). This occurs in fruits of 
species of Cuuoolvulus. Woronin describes the spores as having 
germ-pores through which a septate germ-tube is emitted ; the 
individual cells of the germ-tubes develop into liyphae, without 
formation of conidia. 

Th. affinis Sclnieid. In fruits of Astragalus glycyphyllus {\J .^. America). 
Th. Trailii Cooke. In flowers of Carduus heterophyllus in Scotland. 



THECAPHORA. 325 

Th. Westendorpii Fi>cli. In LiAiam perenne in Belgium. 

Th. pimpinellae Jiifl. In fruits of Pimpinella Saxifraga in Sweden. 

Th. aurantiaca Fingli. In leaves of Urtica dioiat. 

Th. pallescens Fingli. In leaves of Fragana coUina. 



Sorosporium. 

Spore-formation takes place in a mass of twisted gelatinons 
hyphae. Spores at first embedded in a gelatinous investment 
and united into packets, but later becoming separate. Promy- 
celiniii Hlit'iiviii and septate. 

Sorosporium saponariae liud. This causes deformation of 
Howers of Dianthus ddtoides, Sa2Jonari(i officinalis, Silcnc inflata, 
and *S'. vdntina, StcUario ffolostemn, Ccrastium arvense, Lychnis 
fViolcfi, and Dianthus prolifcr. 

S. dianthi Rabh, on Dianthus proUfer, is probably identical with the 
jireceding species. 

We append liere as doubtful Ustilagineae, the genera Graphiola 
Schiiizia (Enturrhizn), Tuberculina, and Schructcria. 

Graphiola. 

The sporocarps of this genus are formed on the surface of 
plant-organs containing mycelium ; they are little spherical 
structures enclosed in a peridium, and contain filamentous 
sei)tate hyphae. The hyphae may be sterile or fertile ; the 
spores are produced on lateral cells of the fertile hyphae. 
From the germinating spores, either a thread-like mycelium or 
sjiiiK lie-shaped conidia arise. 

Graphiola phoenicis Pait.^ (Britain.) Tliis fungus is a 
parasite on leaves of palms ('■.//. J'hai/ii.r i/acfi/li/cni and 
Chiimrrops hinirilis) in tlie ojien in Italy and other Mediter- 
ranean countries, in hot-iiouses elsewhere. The sporocarps make 
their appearance as little lilack i)rotul)erances on both sides <»f 
tiie leaf. The mycelium forms a close liy]»hal tissue, which 
encloses and kills ])ai(iiiIiyniatous cells, (Usplaccs the bundU's 
of sclt-renchyma, and ruiilun'S epidermis and hyj)oderni. 1 )e- 
formalion is, however, locabzi'(l to these spots. 

' Kil. FiMolier, " lieilriig /.. KinntiiiMH d. (Juttiuig '<'/((/'/(i<'/«," linlait. Ziiluiuj, 



326 USTILAGINEAE. 

The sporocarps consist of a two-layered peridium, a sporogenous 
layer, and tufts of sterile hyphae. The outer layer of the 
peridium forms the outer layer of the black protuberances on 
the leaves ; the inner layer is delicate. The sporogenous hyphae 
originate from the centre of the underlying hyphal tissue, and 
form a palisade-like layer in the bottom of the sporocarp cavity, 
the remaining space being filled with spores and tufts of barren 
hyphae. These latter hyphae rise amongst the sporogenous 
ones, and project as a fine brush-like tuft out of the ruptured 
peridium. The sporogenous hyphae grow vertically upwards, 
and become septate, forming chains of loosely united, roundish, 
hyaline cells or joints. The terminal joints give off several 
spherical cells laterally, and die away, leaving the cells loose 
in the sporocarp cavity. From division of the spherical cells 
yellow spores result, and, on rupture of the peridium, are 
carried out on the tufts of sterile hyphae to be scattered by 
wind. The spores germinate in water, and produce either a 
promycelium or conidia. 

Gr. congesta Berk, et Eav. occurs on leaves of Chamcrops 
Palmdta. 

Schinzia (Entorrhiza).^ 

Spores produced on the ends of lateral branches of a mycelium 
in the cortical cells of the root of the host-plant. Germina- 
tion results in production of a simple or branched sporophore 
(promycelium), from which kidney-shaped conidia (sporidia) are 
produced. 

Schinzia cypericola Magn. This causes deformation of the 
roots of Ci-ipcrus Jiacescens (Fig. 179). 

Sch. Aschersoniana Magn. causes swellings on the roots of Juncus 
hufonius [Britain]. 

Sch. Casparyana Magn. In roots of Juncus Tenageiu. 

Sch. digitata Lagerh. In roots of Juncus articulatus. 

Sch. (Naegelia) cellulicola Naeg. In roots of Iris in Switzerland. 

Sch. (Entorrhiza) solani Faut." [This is given as the cause of a disease 
on potato. The plants droop and ultimately rot at the neck, the leaves 
become yellow^ and neither flowei'S nor tubers are produced.] (Edit.) 

^P. Magnus, at Botan. Verein d. Pro v. Bi'andenburg, 1S7S ; " Ueber einige 
Arten d. Gattung Schiuzia," Ber. d. dtutsch. hotan. Ges., 1888, p. 100; C. Weber, 
Botan. Zbituwi, 1884. 

'•^ Fautrey, Revue mycoloy., 1S96, p. 11. 



TUBERCULIN A. 



32; 



Tuberculina, 

Mycelium parasitic on hyphae and spore-patches of UreiUncae. 
Short rod-Hke liyphae spring from the spore-patches, and give 
off from their apices, globose conidia, wiiich on germination 
produce branched promycelia bearing sickle-shaped ciuiidia. 




Fui. 1V9. — Schinzia ryjxricola on Cyperat rtnveaeens. Scvoriil routs nliow pvliuutoly- 
divided HwelliiiKH. Ixolated s|iorc. (Aftvr Miigiius.) 



Tuberculina persicina Ditm. 'Hn' lihu'-cnjoureil spores are 
I'uuiid oil uucidia <»! J'l liilrnaiu la jiini and other at'i'idial tonus, 
also on some species of Cacmna} (IJrilaiii and I'.S. Atucrica.) 



' Plow rij^lit {/{ritiih UHlihujiwdi) gives also A<r, (iJijifrij'olii, Arc. /M^.1i7<^;/lMl^l, 
ml lloi ■ill lilt (an ntta us liosts. 



328 USTILAGINEAE. 

T. maxima liostr. Occurs on rust-patches on AVeymouth 
pine. It has larger spores than the precedmg species. 

Schroeteria.^ 

Spores joined in pairs, rarely in threes, with their broad 
faces together. They are developed from single joints of a 
septate non-gelatinous mycelium, particularly from short curled 
lateral hyphae. Spherical conidia are produced, like those of 
Fenicillmm; by intercalary growth in chains from the end of a 
coni(Uopliore which is generally unbranched. 

Schroeteria Delastrina (Tul.) occurs in seeds of Veronica 
arvensis, V. hcdcrifolia, V. triphylla, and V. praecox. The spores 
germinate in water, and produce conidia incapable of further de- 
velopment, even when transferred to a nutritive solution. In such, 
however, spore-germination is more vigorous, and an abundant 
mycelium results, but it seems to be unable to produce conidia. 

Sch. Decaisneana (Bond.). In seeds of Veroniea hederifolia at Paris. 



UREDINEAE. 

The Uredineae or Hust-fungi possess several forms of spores, 
one of which, the teleutospore, is rarely, if ever, absent from 
the life-cycle of any species. The teleutospores consist of one, 
two, or more cells enclosed in a thick coat of dark colour, and 
thereby well adapted to carry the fungus over winter. When 
germination occurs, each cell of a teleutospore gives off a germ- 
tube through a pore or thinner place in its wall, and from 
this a promycelium- is formed, consisting as a rule of four 
€ells. Each teleutospore originates from a sporophore of its 
own, and in the course of development two nuclei, originally 
present in each cell of the young teleutospore, fuse together. 
When germination takes place, and the promycelium is formed, 
the single cell-nucleus, derived as above, divides into two, then 
into four, so that a nucleus is produced for each of the cells 
of the promycelium. From the promycelium four sterigmata 
are given off, and each produces a single sporidium.- These 

^ Brefeld regards the species as forms of higher fungi, not as Ustilagineae (Heft 
XII., p. 204). 

- Brefeld considers that the promycelium and sporidium are respectively a 
hasidium and a liasidiospore. 



UREDINEAE, 329 

sporidia on gerniination j,dve infecting mycelial hyphae. In 
the case of Coleosporimn , the promycelium is formed inside the 
teleiitospore in a manner similar to the Protobasidiomycetes. 

Besides teleutospores, there occur uredospores. These are 
given ott' from patches or sori throughout the summer till 
autumn, when they are followed l>y teleutospores on the same 
sori. The uredospores somewhat resemble the teleutospores, 
but generally consist of one cell only with a thinner coat of 
lighter colour; they either germinate at once without a resting 
period, and give rise to a germ-tube capable of direct infection 
of new hosts ; or less frequently they are resting-spores for 
a time. 

A third form of spore occurring in the life-history of the 
Uredineae is the aecidiospore, produced in a special structure, 
the aecidium. The aecidinm is developed inside the leaves or 
other organs of the host-plant, and when mature ruptures the 
overlying epidermis ; it has as a basis a firm Inphal tissue, 
the upper surface of which becomes a disc of short erect sporo- 
phores. From each sporophore there is formed by intercalary 
growth a chain of cells consisting alternately of spores and 
smaller intermediate cells, which do not become spores. The 
youngest cells in an aecidium are those next, the sporophore- 
disc, and they are forced outwards by intercalation of younger 
cells between them and the disc. The cells so produced 
become alternately intermediate cells and spores : the former 
increase for a time, then decrease and disajtpear, the spores 
however continue to increase in size as the chain grows forward 
and to take on the characters of the mature aecidiospore till 
they are finally shed from the aecidium. The ])roductiun and 
distribution of aecidiospores may thus go on continuously for 
a considerable time. The sporophores at the i)eriphery of tiie 
di.sc do not however produce spores; chains of cells are also 
produced from them by intercalary growth, Imt the cells are of 
equal size, and remain closely connected with their neighbours, 
so as to form a meml)ran(>us covering over liie .spure-sorus, 
this is the so-called peridium, on rupture of wliicli the aecidio- 
spores escape. In many Treilineae the jit-ridium is su])prt'ssed 
(C(ieoina); in others {PhriiiimiiJinin) it is it-jtlaccd by otlu'r 
structures, the para})hyses. The spores of llic uciius Enditphnllum 
are pnjduceil in series in aecidia enclosed by a jieiidium, but in 



330 UREDINEAE. 

germination they behave more hke typical teleutospores than 
aecidiospores. 

Before the relationship of these various forms of spores was 
known, Accidium and Caeoma were regarded as independent 
groups, and named as such ; even yet many isolated forms of 
uredospores, teleutospores, and aecidiospores are known, the 
relationships of which are quite obscure. 

The aecidia are always preceded or accompanied by a further 
form of spore produced in a special structure of its own. These 
spores have hitherto been called spermatia, and their sporocarps 
spermogonia, on the assumption that they were male organs. 
Now, however, many of them are known to be capable of 
germination in artificial nutritive solutions, hence they are more 
probably a form of asexual bud, and better named conidia, 
their sporocarps pycnidia. The pycnidia are flask-shaped 
structures sunk in the tissue of the host, with a pore or 
mouth emerging through the host-epidermis ; they generally 
occur in leaves, and occupy the upper ej^idermis, the aecidia 
occurring on the lower. From the mouth of the pycnidium 
there frequently emerges a tuft of fine filaments, outgrowths 
from the inner wall of the flask. The pycnidia possess a lively 
colour and flowery odour, hence it has been suggested that 
the conidia may be distributed l;)y insects; but they do not 
appear to be able to germinate in the open, and infection- 
experiments w4th them have never as yet succeeded. On this 
account they are regarded as degenerate structures.^ 

The various forms of spores are also distinguishable by the 
manner in which they bring about infection. Teleutospores on 
germination produce sporidia, which pierce the membranes of the 
prospective host at a spot where two adjoining cells are in 
contact, and thus make their way into tlie intercellular spaces. 
Uredospores and aecidiospores, however, first seek a stoma and 
enter the intercellular spaces of the host through it. 

The following different forms of Uredineae exist : (1) Those 
which possess teleutospores alone, e.g. Chrysomyxu abictis ; (2) 
those with teleutospores and uredospores, e.g. Puccinia j^'^'wiii 
Sjnnosac ; (3) those with all the forms of spores, e.g. Puccinia 
graminis ; (4) those witliout uredospores, e.g. Ggmno.'^pornngium. 

^ Rathay, " Untersucluuigeii iiljer die Sperniogonien d. Rostpilze," Denkschrift 
d. Wiener Ahad. d. Wisseiisch. , ]88o. 



UREDIXEAE. 331 

The difterent forms of spore may be found on one and the same 
host-plant (autoecious Uredineae), or the aeeidiospores and 
pycnidial conidia may frequent a ditt'erent host from the uredo 
and teleutospore-forms (heteroecious Uredineae).^ 

A mycelium may be produced from the germinating aeciilio- 
spores, uredospores, or sporidia. It spreads throughout the 
intercellular spaces of attacked organs and causes tliickening, 
distortion of the tissues of its host, or the formation of " witches' 
brooms." Nutriment is frequently obtained by means of cone- 
shaped or button-like haustoria in the interior of host-cells. 

Hibernation of rust-fungus is most commonly attained through 
the teleutospores, tlie thick coats of which make them peculiarly 
suited to pass through a lengthened resting- period. Some forms, 
however, hibernate by uredospores, by aeeidiospores, or by the 
mycelium remaining on or in living perennating stems, twigs, or 
underground rootstocks of their host. 

• Aeeidiospores on germination produce, as a rule, a mycelium 
which gives rise to uredo- or teleutospores, rarely to aeeidiospores 
{e.g. Puccinia senecionis and Uromyca^ erri).- Ureilospores on 
germination, produce a mycelium from whicli uredospores are 
first given oft", then teleutospores. The sporidia of teleutospores 
give rise to a mycelium which frequently produces pycnidia 
and aecidia. In rare cases, the sporidia of species, which normally 
form aecidia, are said to develo}) a urt'dd-niyceliuiu ('.//. J^ncc. 
(jraminis according to Plowright). 

The Uredineae are for the most part strict parasites, and 
exhibit marked adaptation to their respective host-plants. Several 
of the polyxenous members frequenting several species of host- 
plant have been found to vary according to their habitat, so that 
one and the same sjiecies assumes a slightly dill'ereut i'nnn on each 

'The phenoiiieiion of lieteioecisiu was till (|uite recently known onl_v uinongst 
the Uredineae. Woronin and Xawa.scliin have, however, recent!}" pointed out that 
it exists in Srltroliuia Itdi, one of the Asconiycetes (p. 277). The conidia of 
this species are produced only on Varrinhnn ii/iijiiioiinn, the apoihecia only on 
Ltiltim, and altei-nate with each otlier, so that the LkIidh can l)e infected oidy 
by germinating conidia, the Varrinium \>y germinating ascosj)orcs. 

-l)ietel (S'filttrl'ortirh. Venin in Vkiina, 1894) pointed out furtlier ca.ses of 
this kind, in which aecidia were pr<jduced the sununer througli, and no 
uredospores, wiiile in autunni teleutospores were formed. He lias more recently 
stated tlie general conclusion {/'"/urn, 18!!.'), p. .'{'.14) ; tliat with tlic^c species of 
Uroiiujrix and I'lirriiiin, which produce aeciilia and tcicutospoics, liut no uredo- 
spores, the aecidiospoi'es are capalde of i'e])roducing aecidia when no perennating 
niyi-elium is jircscnt. Similarly witii those few species whicli produce a very 
small niimlicr of nrcdospoics. 



332 UREDINEAE. 

host-Species. I have previously shown/ with regard to the 
mistletoe ( Viscuvi album), that the different forms on Finns, 
Abies, and various broad-leaved trees, which some authors regard 
as distinct species, might equally well be regarded as forms of 
one species differing slightly on account of their different 
substrata. Magnus ^ designates as " habitat-races " these forms 
of heteroecious Uredineae whose aecidial generation has become 
adapted in some varying degree to each of their respective 
species of host-plant. Thus the various forms of Accidium 
convaUariae, on its different host-plants, he regards as forms of one 
and the same fungus, the Fuccinia of which occurs on Fhalaris 
artmdinacea. 

The manner in which such adaptations originate is indicated 
by my experiments with Gymnosporanyuim. Thus G. clavariae- 
forme can infect leaves of Crataeyus and produce aecidia 
without failure ; whereas the same infection carried out on 
Sorbus and Cydonia results in incomplete development of aecidia 
(see Table, p. 385). In this way there might easily be pro- 
duced one form which infected Crataeyus, and another confined 
to Cydonia. The same thing occurs with the various Fcridcrmia 
of pine-needles ; these, according to tlie investigations of 
Klebahn, are caused by one or other species of Coleosjjoriutn 
from very different species of host-plant.^ 

The best examples of all, however, are presented by the 
cereal-rusts, as demonstrated by Eriksson. This investigator 
believes that the forms distinguished by him as " specialized 
forms " (by Eostrup as " biological species or varieties ") are 
of common origin. In course of time these have taken on 
different biological characteristics in adapting themselves to 
the varied nature of their substrata, their various host-plants, 
so that in many cases they can no longer suit themselves 
to the host-plant of the original parental form. In fact, species 
were found with aecidia of similar shape when occurring on 
the same host-plant, yet completely specialized from the aecidia 
on another host. They thus present a stage intermediate to 
that of the " habitat-races " just mentioned. 

'v. Tubeuf, Jiofan. CentruU.kitt, \h., 1889, p. .312. 

~ Hedwirjia, 1894, p. 77, and 1895. 

"■ Klebahn's views on this subject, along with furtlier investigations on other 
fungi, will be found in Ztitschri/t f. PJlanzcnhankheiten, 1895, p. 153. 



UREDIXEAE. 333 

The european Urediueae comprise tlie followinj^ families and 
genera : Puccinieae ( Uroimjccs and Puccinia) ; Phragmidieae 
{Tripltraijinium and Phragmulium); Melampsoreae {Mela m psora, 
Mdampsorella, Cahjptospora, Coleoajjonuni, Chrysovii/.m, and Cron- 
artium) ; Gymnosporangieae {Gymnosporangium) ; Endophylleae 
(Endophi/Ilum) ; also the genus Ureclinopsis on Ferns. 

Uromyces. 

Teleutospores unicellular and produced in flattened sori. 
Only one teleutospore is abjointed from each sporophure. 
Teleutospores with a single germ-pore. Uredospores, aecidia, 
and pycnidia are not present in every species. 

(1) AH far Ills. <if spore present on the same host-plant : 

Uromyces ervi (Wallr.) (Britain).^ Vetch-rust. The aecidia 
are produced on Vieia hirsi'.ta in May and throughout the 
suuHiier. Scattered amongst the aecidia are the sori from 
which uredospores are sparingly given off in early summer ; 
the teleutospores are given off abundantly from the same 
sori from July onwards. The aecidiospores germinate on the 
vetch plants, and produce therein a mycelium from which the 
aecidia and teleutospores arise. Infection by means of spuridia, 
derived from the teleutospores, results in the production of a 
mycelium which bears aecidia only. Pycnidia (spermogonia) 
are absent in this species and also in U. /abac. 

U. fabae (Pers.), [U. orohi (Pers.)] (Pritain and T.S. America). 
This occurs on species of Vieia and Lathijnix. Sori are formed 
abundantly and give off l)oth uredospores and teleutospores — 
the latter being smooth-coated. Xo ])yinidia have as yet l)een 

oliser\-e(]. 

U. trifolii (lledw.). Clover-rust. Parasitic on \arious species 
of clover. I'redo- and teleutospores are generally })roduced ; 
aecidia have Ijeen found only on Trifolium repens (Germany ami 
liritain), T. incarnatum (Italy), T. pratcnsc (Denmark, P.ritain, 
and America). On Trijhlinni rej)ens both teleutospore and 
aecidium generaliuns cause swelling and distortion of leaf-ribs 
and peti(jles, the deformation being most marked where the 
mycelium has hibernated and )irn(hiif(l telrutospori's in spring. 

' Tliu cliicf uulhorilicH iisetl fm' the <k.ciiiiuiico of the dctliiu-ac in liiiUiiii 
urnl Ninth .Xincrica are l'lowrij.;lit (Hrilinh i'rfi/iwne, 1889), ami Fallow and 
Suyiiioiii- {/fo^l-Iii'lix fur U.S. Anil lira, iSiH). (I-Mit.) 



334 UREDIXEAE. 

U. appendiculatus (I'ersj, [U. phrmoli (Pers.)]. On species 
of Fhasrolt'S. ( Britain and U.S. America.)^ 

U. primulae Lev. On Frimida fiirsv.ta. 

U. limonii (D. C). On Armen'a and Statice. (Britain and 
U.S. America.) 

XJ. polygoni (Pers.). On Polygonum and Humex. (Britain 
and U.S. America.) 

U. acetosae Schroet. On Humex. 

U. silenes rSehlecht.). On Silene and Dianthus. 

U. euphorbiae (Schwein./ On JSvphorhw Freslii in Italy, 
and some other species in America.- 

U. geranii CD. C). On Geraniums. (Britain and U.S. America.) 

U. betae (Pers.). On Mangel Wurzel and Bef.a. (Britain 
and U.S. America.) 

U. pamassiae (D. C). (Britain.; 

U. salicomiae (D. C). (Britain.) 

U. Valerianae (Schum.). On Valeriana difAca (Britain). 

(2) FycrnyliM {spermogonia.) a/iuX a^cidia. prodvxed (/a, one host; the 
related nrfdo- and teleutospfrres va a/nother host: 

Uromyces pisi (Pers.; (Britain) Pea-rust. The uredospores 
and teleutospores are developed in various species of Fisum, 
Laf.hyrv.s, and Vuia. The teleutospores are finely punctured. 
The aecidia appear on the under surface of the leaf of Ev.pjhorhia 
Cyparissiaji, and are preceded by pycnidia. 

Attacked plants of Euphorbia, become completely changed in 
their appearance. The stems are much elongated, and a.s a 
rule remain unbranched. Floveers are seldom or never produced ; 
if so, they are permeated by mycelium and deformed. The 
leaves are short, thick, and rounded-off: they have a pale-green 
colour, and are distant from each other on the shoot. Their 
internal structure is also considerably modified. Wakker states 
that the cells of the mesophyll become enlarged, while no 
coUenchyrna is developed in the ribs. Fentzling' gives the 
following changes : the epidennal cells become broader ; stomata 
are more numerous on the upper surface of the leaf, and fewer 
on the lower ; the laticiferous tuVjes below the upper leaf- 

' Deacription, illoiftratioD, and treatment in ^V. Yr/rk Affric. Exp^.r. Station. 
B^jJ.L, 4H, \H'.r2. 

* Magnois, Btricht'; d. deutifch. fjotan. 6'e*., 189.3. 

' " Untenrachung d. Veranderungen welche durch Rostpilze her\'orgenifen 
werden." Inaogural DiBsertation. Freiburg, 1892. 



UROMYCES. 



335 



epidermis are reduced in numl:>er : intercellular spaces are formed 
in the normally compact palisade parenchyma, and its cells 
become shorter and broader, while those of the spongy p»aren- 
chyma are increased both in size and number ; the tibro-vascular 
bundles remain unchanged, although the cells surrounding them 
may be more or less abnormal. Where thickening of the stem 
takes place, it is chiefly due to multiplication of the cells of 




cortex and pith, while at the same time those of the cortical 
parenchyma l>ecome somewhat enlarged and altered in shape : 
the woody jxirlion is less developed than normally : and 
laticiferous tubes are neither so large nor so conspicuous as 
usuaL 

The aecidia of this species are fc»und only on ilie lower 
surface of the leaf: they are saucer-shaped, and have a bn»ad 
lobed white raanjin. 



336 UREDINEAE. 

As a preventive measure, it would be advisable to keep 
down spurge-plants near fields or gardens where peas are likely 
to be attacked. 

U. striatus Schroet. (U. S. America). Uredo- and teleutospores 
on species of Lotus, Mcdicago, Trifolium, and sometimes Vicia. 
Pycnidia and aecidia are produced on Euj^horbia Cyparissias ; 
the mycelium induces changes in the tissues similar to the 
preceding species, but the Euphorhia remains stunted instead 
of elongating as in attacks of U. jjm. 

U. dactylidis Otth. Uredo- and teleutospores on species of 
Poa, Dadylis, Avena, and Brachypodium. Aecidia on several 
species of Eanunculus (not on B. Ficaria). (Britain and U.S. 
America.) 

U. poae Rabh. Uredo- and teleutospores on Boa ; Aecidia 
on Bmuuiculus Ficaria, B. hulbosus, and B. repens. (Britain). 

U. lineolatus Desm. {U. maritimus Plowr.).^ Uredo- and 
teleutospores on Scirpus maritimus. Aecidial tovms = Aecidium 
sii latifolii on Sium and Aec. hippuridis on Hippuris, also a 
form on fllavx maritima in Britain. 

U. junci Desm. Uredo- and teleutospores on species of Juncus. 
Aecidia on Bulicaria. (Britain and U.S. America.) 

(;5) Only uredosporcs und teleutospores known; they frequent 
the same host. 

Uromyces caryophyllinus (Schrank.)^ Carnation Eust. [This 
attacks carnations at all stages of growth. The mycelium extends 
inside the plant and forms spore patches which rupture the 
epidermis. Uredospores are produced first, then the teleuto- 
spores ; the former germinate at once, the latter only after a 
resting-period. The use of sprays of potassium sulphide or 
copper sulphate, and the cultivation of hardy varieties have been 
recommended.] (Edit.) 

Uromyces scutellatus (Schrank.). On species of EuphorUa. 
The mycelium is perennial in the root-stock and permeates the 
whole plant. Teleutospores developed in dark-brown spots on 
the under surface of leaves. Diseased stems are generally un- 
branched, and carry only small leaves and no flowers. 

^ Plowright, Gardener's Gkronidt, 1890. 

-Halsted, N. Jtrseii Agric. Coll. Exper. Station Report, 1891. Atkinson, 
"Carnation Diseases," American Carnation Soc. ; witli Illustrations. N. York 
Aijric. Exper. Station Bulletin, 1896. 



UROMYCES. 337 

U. tuberculatus Fuck. <.)n Eu/jltorbia e.rijjnu. 

U. prbeminens Dubv. Oii species of Euphorbia. 

U. sparsus (Kuiize et Schni.). On Speiyulan'a, aiul Stellaria (Britain). 

U. Schroeteri De Toni. On Lychnis and Silene. 

U. cristatus Scliroet. et Niessl. On Visiuria and J)ianthus. 

U. ficariae (Schum.). On Ranunculn.s Ficaria (Britain and U.S. 
Ana-riwi). 

U. astragali (Opiz). On Astnujulus (U.S. America). 

U. genistae (Pers). On Genista, Cytims, Vulutea, Galeya, Caragana, 
Onybjychi's, etc. 

U. anthyllidis ((Jrev.). On Aidhyllis and Lupinns (Britain). 

U. lupini Sacc. On Lupinus (U.S. America). 

U. trigonellae Pat. On leaves of Trigonella Foenum-graecum in France. 

U glycyrrhizae Raljh. On Ulyryrrhiza. 

U. cacaliae (D. C). On Adenostyles and L'acalia. 

U. rumicis (Sclnin).). On Rumex (Britain). 

U. alpinus (Schroet.). On Rumex alpinus. Mai,'niis ' lias recently sep- 
arated this as the single species of a new genus Schroeteriaster, allied to 
froiityx's and I'uixinia. The uredospores arise from patches of sterigmata 
without peridia or parajjliyses ; they are unicellular and have lateral 
germ-pores. The teleutospores are also unicellular, and form lentil-shaped 
patches composed of five or more layers of spores ; the spores have a 
somewhat thickened apex, but no distinct germ-pore. 

U. chenopodii (J)uby). On Chenopodium and Schoheria. 

U. terebinthi (D. ('.). On FiAtacia and Rhus (U.S. America). 

U. brevipes (B. et R.). On Rhus Toxicodendron in America. 

U. ambiguus (D. ('.). On Allium Scorodoprusum. 

U. acutatus (Kuck.). On Allium. 

U. veratri. ( I >. ('. ). On Vcratrum. 

U. alchemillae (Pers.) (Britain). This is a species whiili 
ill iuildt rt'scinlilt'S a Fhriig)ni<lii(iii, ami is sutuetimes regardetl 
as a representative of a separate genus — T ruchyapora (Fuck.). 
It forms patches of reddish-yellow uredospores or brown teleuto- 
spores on the lower surface of leaves of Alchcmillu ndijuris. 
Aeci(li:i iin- unkiiMwn. 

(4; I'ljraiilin, (ixvid'm, and Ich utospurcs on the same host-phtnt ; 
urrdnspDrcs mi/./ioirn, 

Uromyces excavatus \l ('.) Magn. <)ii /■Ji/j,/iorIii>i (,'rr- 
anlinii'i, K. ri rrucufiU, etc. 

U. Behenis (D. U). On Silene. (Britain.) 

U. lapponicus ha^jiih. ( )ii AstragnluA in Noiway and tin- Alps; accidia 
only in iIk- latter locality. 

^ Rfrirfih il. ihiilsrli. 1,,,/aii. (.>••., IMMI, |.. 1 .'50. 
V 



338 UREDINEAE. 

U. minor Schroet. On Trifolium montanum (U.S. America). 
U. hedysari-obscuri (D. C). On Hedysarum in Europe and America. 
U. scrophulariae (D. C). On Scroplmlaria and Verhascum (Britain). 
U. erythronii (D. C). On Lilmm, Mtbscari, Scilla, Allium, Fritillaria. 
(U.S. America). 

(5) Tcleutosjyores alone known; after death of the host they 
undergo a resting-period, then germinate : 

U. solidaginis (Somm.). On Solidago virgaurea. 

U. phyteumatum (D. C). On Phyteuma, accompanied by elongation of 
the leaf-stalk. 

U. scillarum (Grev.). On Scilla and Muscari. (Bi'itain.) 

U. ornithogali Lev. On Ornithogalum and Gagea. (Britain.) 

U. colchici ^lassee. On Colchicum spectahilis at Kew.^ 

(6) Tclevtospores alone known; germinating at once on the 
living hod : 

U. pallidus Niessl. On Cytisus. 

(7) Oiily teleutos2Jorcs and irycnidia known; present on the same- 
host : 

Uromyces Tepperianus Sacc.^ This causes on twigs and 
branches of Acacia a deformation consisting in an all-round 
swelling followed by rupture of the periderm and the develop- 
ment of brown teleutospore patches on the exposed wood. Tepper 
found in South Australia shrubs of Acacia scdicinia and A. 
myrtifolia attacked and killed ; the former, near Adelaide, being 
almost exterminated. He also found it prevalent on Acacia, 
spinescens, A. hakioides, and A. myrtifolia in another part of 
Australia (Murray Bridge). 

The same fungus was found by Warburg on Alhizzia montana 
in Java, likewise by Solms-Laubach and Stahl (Fig. 181). 

Magnus^ found that Warburg's specimens showed the rupture 
of the rind only on one side, those of Stahl, however, agreed 
with the Australian specimens. On investigation of the galls, 
Magnus found a multiseptate and intercellular mycelium with 
numerous and somewhat branched haustoria. The formation 

^Grevillea xxi., 1892, p. 6. 

^Ludwig, " Eine neue Rostkrankheit australischer Akazien," Ctntralhlatt f. 
Bakter u. Paradttiikimde, 1890, p. 83 ; further : Hedu-inia, 1889, and Forst- 
lich-naturwiss. Zeitschri/t, 1894. 

■'Magnus, Bej-. d. deut'^ch. holan. GeselL, 1892, p. 195; Hennings, Ftmgi 
Warhiirtjiani, Hedivigia, 1893. 



UROMYCES. 



339 



of pycnidia precedes that of teleutospores. The latter have 
a flattened concave base and rounded apex ; their episporium 
is marked with delicate ribs running from apex to base. 




Flii. IS\. — I'roiit'ic.A T'i'P' ririiiii..i mi twigs of All>i::io. monlann tjioiighl l>y 
I'rof. .Stiihl from Jiivti. (v. Tubeuf phot.) 



Puccinia. 

Tideutospores two-celleil, and I'ach alijuiMlt'd I'miu its own 
.sponjphore fn^n large distinct sori. Ivich cell has a.s a rule 
only «jne germ-pore. Uredosporcs, telcutospoivs, ami pvcniiha 
(sperniDgDniu) are not known in all the species. 

(l) I'l/iatil III, iiiriil ui , II riilosponx, (inil fr/i iifusfions (/irrloji on llif 



340 UREDINEAE. 

liviny host. The latter, however, germinate only on death of the 
host and after a resting-j)eriod {Eu-puccinia, Schroeter). 

(a) Auteupuccinia : all forms of spore are j^resent on the same 
host-plavf. 

Puccinia helianthi. Schweiu. Suutiower-rust. This danger- 
ous enemy of Helianthus was first observed in South Carolina 
and Pennsylvania, U.S. America. In Europe it appeared first 
to a serious extent in Russia, where the sunflower is cultivated 
on a large scale ; now it has a very general distribution. In 
America it attacks both sunflower {H. annuus) and Jerusalem 
artichoke {H. tuberosus), but its presence on the latter is as 
yet doubtful in Europe. The mycelium appears first in the 
lower parts of the plant and thence extends upwards ; its 
presence is indicated by large brown leaf-spots, on which the 
uredo-patches arise about the end of June. The teleutospores 
make their appearance in autumn ; the aecidia and pycnidia in 
spring (Aec. helianthi Wor.). Combative measures consist in 
burning, or otherwise destroying, all sunflower debris in autunni. 

P. cirsii Schroet. On Carduus Icmceolata. (Britain.) 

P. prenanthis (Pers.). On Frenanthes, Lactuca, and Midge- 
dium. (Britain and U.S. America.) 

P. lampsanae (Schultz). On Lampsana. (Britain.) 

P. montana Fuck. On Centaurea. 

P. violae (Schum.). (Britain and U.S. America.) The Violet- 
rust. This parasite appears on both wild and cultivated species 
of Viola, and frequently causes much damage. Malformation 
and stunting of the host may accompany the formation of 
aecidia. Fentzling investigated the swollen outgrowths produced 
on the lower surface of the violet leaves, and found an increase 
in all forms of the leaf-parenchyma ; the spongy parenchyma 
included more cells, while both spongy and palisade parenchyma 
consisted of rounder cells more closely packed together than in 
the normal. 

P. aegra drove. On Viola cornuta, etc., and somewhat 
different from the last species. (Britain.) 

P. mirabilissima Peck. On Berheris repens in America. 

P. silenes Schroet. On Silene and Lychnis. (Britain.) 

P. pimpinellae (Strauss). On Pimpinella, Ghaerophyllum, 
Anthriscvs, Myrrhis, Athaniantha, Ostcricum, Angelica, fferacleum, 
Eryngium, etc. (Britain and U.S. America.) 



PUCCINIA. 341 

p. saniculae (irev. ( )n Saalrulu europaca. (Ihituin and 
U.S. America.) 

P. soldanellae (D.C.). (Britain.) On various species of 
Soldamlld.. Tliis disease is often very common in the mountains, 
and is conspicuous because it attacks only leaves here and there 
on a plant. The leaves are yello\vi.sh with petioles distinctly 
elongated ; tlieir laminae, which bear aecidia on the lower side, 
are smaller and somewhat cup-shaped. Diseased plants do not 
seem to Vilonm. 

P. menthae (Pers.). (Britain and I'.S. America.) This is 
a most destructive rust to all kinds of cultivated mint. It 
attacks species of many genera of Labiatae. 

P. calthae Link and P. Zopfii AVint. On Caltha paln.stris 
in Kumpt' and North America. 

P. epilobii-tetragoni (I>.C.) (P. puhrrnlnita (Irev.). On 
Epilulnii ,11. (Ilriiain and U.S. America.) 

P. Peckiana Howe \r. latn-ditialis (Schlecht.)]. This species 
occurs on several species of Rnhvs in America, ami causes con- 
siderable damage in blackberry culture.^ 

P. gentianae (Strauss). On (ieiitian. (Britain and U.S. Ameiica.) 

P. galii (Pers.). On G'ali'um and Aft/H'n>/a (Wnodniti). The teleiitospdies 
liil>ei nate on the dead steui.s. (Britain and U.S. Anieiica.) 

P. convolvuli (Pers.). Ou Convolvulus. (Britain and U.S. America.) 

P. primulae (J). ( '.). < )n species of Pi-imulu. (Britain.) 

P. obtusa S<liru.t. ( )m Salvia verticillata. 

P. thesii (I>es\.). ( )n Tlmxium. (Britain and T'.S. America.) 

P. albescens (< iitv.). ( )n Ado.in Monclinti-Uiiiit. (Britain.) 

P. aristolochiae ( I ». ('.). ( )n Aristolor/iiit. 

P. asparagi ( 1 ). < ' ). ( Britain and U.S. America.) A.sjiarairus i list. The 
teleiitospoies liil.einatc in (\i\ remains of tlie |ilants. wliicli shouM therefore 
lie liiiiiit ill autumn. 

P. porri (.Si.w.) ( )iiion-rnst. On lioth uihl and cultivated Allimn. 
Sometimes very destrni tive to chives (.1. ^i/itH-nujiritKinn). (Britain.) 

(/') Hifrrriipiniiiiiii, l^rrt/uspnrrs iilid tclruUtsporcx (Irrrlojird 
nil II Inisf iitJii r lliiiii tliiil iif till jn/niii/if( (oid nicidia. 

Puccinia graminis I'ers. (I'.iiiain and U.S. America). I'.lack- 
rii>l (»)• >uiiiui<'r-ru>l.- rreiln^pdrrs and irlciititspores nccur nn 
various species (if ( Iranuiicae, ihr pycuidia ami aeeidia <in 
species (it Jiirlnris or Mulinnin. 

' ( 'Hilton in lii /Hjil III' Aijiiiuliiiinl Sinlion of Uuirtrtiltf of INiiioii, IX!I3. 
-A Vidiiiilile iiioiii)^ra|ili on the niHtH of eerealn liiis lieen pultllHlieil l>y 
KiikM>oii ,111,1 M.imin;.' (/>;- '.V^-. /</. /v,*/. . .-^tockliolm, I89(i). 



342 



UREDINPJAE. 



The two-celled teleutospores arise from cushions or sori 
which form black lines on the haulms and leaves of grasses ; 
they hibernate on the decayed remains and germinate in spring. 
Each cell of a germinating teleutospore 
gives off a four-celled basidium (promy- 
celium), with four short sterigmata from 
each of which a basidiospore (sporidium) 
is abjointed (Fig. 182). The sporidia are 
carried off the grass-host and germinate at 
once if they alight on leaves or flowers of 
Berheris or Mahonia (Fig. 183). Germ- 
tubes are formed which penetrate the outer 
walls of the host into the epidermal cells. 
The mycelium which results is a branched 
septate one, and spreads through the inter- 
cellular spaces of the leaf. About eight 
days after infection, little yellow spots make 
their appearance on the upper surface of 
the leaf. Embedded in the spots will be 
found the pycnidia (spermogonia), spherical 
flask-shaped enclosures developed on a web 
of hyphae, and with their inner walls clad 
with short rod-shaped conidiophores (sterig- 
mata), each of which gives off a tiny coni- 
dium (spermatium) (Fig. 184). A tuft of 
periphyses arising from the upper part of 
the pycnidium wall carries the conidia out 
of the pycnidia in drops of a honey-like 
fluid emitting a characteristic odour. In 
regard to the function of these conidia 
nothing definite is known. 

The next stage begins with the appear- 
ance of yellow spots on the lower epidermis 
of leaves. These indicate the presence of 
a mycelium from which the aecidia take 
their origin. The aecidia are at first en- 
closed in a one-layered peridium under 
the leaf-epidermis, till by their increasing size they rupture both 
coverings, and project above the surface as cups containing 
spores (Fig. 184). The aecidiospores originate in a layer of 



Fig. 182. — Puccinia (iram- 
inis. Germinating teleuto- 
spore. The promycelium 
has formed three sterigmata, 
from the ends of which 
sporidia are in process of 
abjunction. (After Tulasne.) 



PUCCINIA. 



343 



hyphae forming the bottom of the aecidium-cup. These hyphae 
give rise to numerous short sporophores, from each of wliich 
a single long chain of spores is abjointed in basipetal succession, 
the spores being at first separated l)y temporary intermediate 
cells. The sporophores mund the margin of each aecidium do 
not, however, give off spores ; they also produce chains of 
cells basipetally, but these grow larger and, without the inter- 
vention of intermediate cells, remain sterile and become joined 




Fig. 183. — Puecinio i/ramiiiii (Aeeidiuiii lnrUriJis) on BerUris co»niiuni». Tlie 
lowest leaf and tWD othcis ure Hccn on the upper surface, and show red spots with 
liKht niarto»», i" which the pycnidia are embedded. The other leave.s «how the 
under surface with patches of aecidia. (v. Tubeuf del.) 



to their iieighljours to I'oiiii the peiidiuiu. diseased ])i)rtinns 
of leaves become considerably thickened. The cells of the 
single layer of palisade parenchyma are abnormally elongated, 
and the intercellular spaces of the spongy parenchyma, instead 
of being large, are small and filled wiili mycelium. The aecidin- 
spores escape in July to germinate <ju (Iramineae. The germ- 
tube enters tiu; host by the stomata nidy, and develoj)s into 
an intercellular mycelium ; this in about eight days jimduces 
uredospores from oishions or suri which form lines, ainl l»reak 



344 



UREDINEAE, 



through the epidermis. The yellow uredospores are abjointed 
singly frcfra long sporophores ; they are unicellular and ovoid, with 
a thin granular coat beset with germ-pores (Fig. 184). The uredo- 
spores are easily conveyed to other grass-plants and germinate at 
once, their germ-tubes entering by a stoma and developing into 
a mycelium, which can produce a new crop of uredospores in a 




Fig. 184. — Puceinia graminis. A, Portion of transverse section of leaf of Berberis 
vulgaris, with a young aecidium under the epidermis, v. 

I. Section through an aecidiuni-bearing spot of a Barberry leaf. At x the 
normal structure and thickness of the leaf is shown, the portion u to »/ is 
abnormally thickened ; h to o, upper surface of the leaf ; sp, pycnidia ; a, aecidia 
in section ; p, their peridium. The aecidiumi marked p alone (without a) shows 
a peridium exposed in suiface-view only. 

II. Mature teleutospore-patch breaking through the epidermis, e, from the 
tissue, Ij. of a leaf of Triticum re'pens ; t, teleutospores. x 190. 

III. Teleutospores, t, and uredospores, «;•. The teleutospore has a germ-pore 
at its apex, the uredospores have four germ-pores at their equator. x 390. 
(After De Bary, from Sach's Lckrbv.ch.) 

few days. The uredospores are summer-spores, and spread the 
fungus during the vegetative period of the host-plant ; they may, 
however, hibernate. The teleutospores are more suited for 
hibernation ; they are produced in autumn from dark brown 
linear sori, distinguished from these of the uredospores by their 
darker colour and greater length. The teleutospores are two-celled 
and obovoid with smooth thick walls (Fig. 184); they are, like 



I'UCi.INIA. 345 

the uredospores, developed from loni,' sporopliore.s, und are in 
this way distinguished from those of Poec. ruhigo-irra, which 
are very short. The teleutospores germinate in spring after 
hibernation, each cell giving off a single germ-tube. 

Both uredospores and teleutospores are injurious to our 
cereals, — wheat, oats, and rye. They may also be founil on 
the following species of grasses: Antlioxanthum, Ahtpccurus 
I'hlcnm, Ayrostvi, Aim, Acena, Briza, Aii^henatherum, Poa, 
Duftylis, Fcstiaa, Bromtis, Triticum, Seca.Je, Eli/niKS, Hordfum, 
Ldlu/m, Ayropyrain, Am/rupnyon, Bryziqjyrain, etc. 

The disease may ruin a whole harvest of grain, and render 
the straw disagreeable, if not dangerous, for stable use (see 
also p. 84). Kemoval of barberry bushes is said' to reduce the 
rust, although many believe that the barberry is not necessary 
for the existence of the fungus.^ I'lowright, for example, found 
that sporidia from teleutospores infected wheat-seedlings directly, 
without intervention of the aecidiospore stage. It is also possible 
that the mycelium hibernates like that of Pace, ruhiyo-vcra, in 
sDuie wild gra.ss, to grow again and produce uredospores in spring. 

No very eff"ective measures against this fungus are known. 
Karly sowing has been suggested; and certain varieties of grain, 
known to be les.^j liable to attack than others, might l)e used. 

Eriksson and Henning,- from the results of tlieir infection- 
experiments, liave provisionally distinguished ijie folhiwing 
varieties of P. yraminis: 

A. Definite — («) distinct varieties: 

1. Var. sccalis on Secale ccreale, Horih urn ruhjui;-^ Tritinini 

irprns, and Ulymns arnuiriiifi. 

2. \'ar. firniar on Acena sntini, Miliinii ifl'usii/ii, Ahrpiciirtia 

pmti'nsis, Ddctylia yluminita (and Ar,nii ildtinr). 
'•*}. \'ar. fdrni' on Aim rarsj)ifos(i. 

(y8) somewhat uncertain vai it-ties: 
4. \'ar. iiyrn.'itiji on Ayrostis caniim, and A. sfofoni/em. 
■ >. \nv. pour on Piifi nniijirrssfi (and /'. /mifi nsis). 

H. Not sharply detint^d : 

G. \'ar. tnhci (III Trttim III rnhiiirt'. 

' .\ii iiitt-rcHting iliHcitoHion of this .siilijtvl is ^'i\iii liy \\'"r. (i. Smitli (hitroMH 
uj Uro/iH, Cliap. xxv.). (Kdit.) 

- KrikHHoii mill llL-niiin^, " riiior.Hiiiliiiiij^'tii iil». il. (tetifiilui«>«lu,'' Ziitsrh. 
f. /'fUur.'idraidh'ihii, Isilj. 



346 UREDINEAE. 

Puccinia coronata Corda. (Britain and U.S. America.) 
Eriksson, from his own experiments and those of Klebahn, 
distinguishes the following specialized varieties : 

Ser. I. Aecidia on Bhamnus cathartica, Rh. elaeoides, Bh. 
grandifolia, Bh. alnifolia {Puccinia coroiiifera Kleb.). 

1. Var. avenac on Avena sativa. 

2. Var. alopecuri on Alopccurus pratensis. 

3. Var. feducac on Festucct elatior (and F. ruhra.). 

4. Var. lolii on Lolium iKrcnne. 

In addition to these, Klebahn found a form on Avena elatior, and one 
on Holcus lanatus, in regard to whose specialization nothing is known. 

Ser. II. Aecidia on Bhamnus Frangula {Puccinia coronata I., 
Kleb.). 

5. Var. calamagrostis on Calamagrostis arundinacea (and 

C. lanccolata). 
In addition : forms on DactyUs glomeratu, Festuca sylvatica (? Puce, 
gibberosa Lagerli.), Agrostis vi/lgaris, Holcus lanatus (? H. mollis), and 
Phalaris arundinacea. 

Ser. III. Aecidia on Bhamnus dahurica {Puce, coronata var. 
himaUnsis, Barcl.). 

Indian forms on Brachypodiwn sylvaticum, {Piptathentm holciforme, and 
Festtica gigantea,) of which nothing more is known. 

Ser, IV. Aecidia unknown, probably do not exist. 

6. Var. melicac on Mclica nutans. 

Amongst our cereal crops the oat alone is attacked by this 
species, and much damage may result. 

The uredo-patches have no paraphyses like the preceding 
species, and they form reddish-yellow spots and stripes ; the 
teleutospore-patches are black. The upper cell of the teleuto- 
spores is surrounded by a crown of six or seven blunt teeth. 

The presence of aecidia on Bhamnus is accompanied by 
thickening and twisting of young shoots, and blister- like de- 
formation of leaves, calyces, and ovaries. Wakker^ thus 
summarizes his investigations on the anatomical changes induced 
by the fungus on Bhamnus Frangula : " It causes the cells 
of every part to become abnormally enlarged, at the same time 
giving rise to an orange coloration of the cell-sap and an 
accumulation of starch ; there is no longer any formation of 
interfascicular cambium, and there is a partial or complete 

' Wakker, PringsheinVH Jahrburh, 1892. 



PUCCINIA. 347 

suppression of secondaiy vasa, mucilage canals, and calcium 
oxalate." 

The deformation induced by 1\ coronata on lihamnvs catJturfica 
was investigated by Fentzling.^ The changes were relatively 
slight : the parenchymatous cells of the rind were enlarged 
and separated by large intercellular spaces ; so also the paren- 
chyma of the bast ; vessels were more numerous in the wood 
affected ; the epidermal cells in some parts of the leaf were 
broadened and those of the mesophyll enlarged, abnormally 
shaped, and with large intercellular spaces ; in diseased leaf- 
stalks the epidermal cells are thinner- walled and broader, while 
all parenchymatous cells become enlarged, thinner- walled, and 
with many intercellular spaces ; the fibro-vascular bundles are 
enlarged, chiefly from an increase of the wood-parenchyma ; this 
tissue, in normal petioles, occurs as single rows of cells running 
radially between the vessels, whereas, in diseased places, three 
parallel layers of cells may separate neighbouring vessels. 

P. dispersa Eriks. et Henn. Brown-rust. (Britain.) The follow- 
ing specialized varieties of this species have been distinguished : 

Ser. I. Aecidium on Anchusa arvensis and A. officinalu {Aec. 
anchusae). 

1. Yav. stcalis on Scca/e ccrcalc- 

Ser. II. Aecidium unknown. (Wliether distinct varieties, 
somewhat uncertain.) 

2. Ycir. fritici on Tritlcum vulgarc. 

'). Var. hromi on Bnnnvs arvensis (and Br. hrizacformis). 
4. XwY. iiiiropi/ri on Triticvm rcpttis. 

P. rubigo-vera (D.C.) {P. sframinis Fuck., P. striaefonnis A\'est.). 
(Britain and I'.S. America.) This, in its uredo- and teleuto- 
spore stages, frequents various grasses, while the aecidia occur on 
JJoragineae. A variety on species oi Hurdi mn has been designated 
P. siniph'j:. The teleut(jspore-]iatclies are enveloped in nunierous 
brown paiaphyses ; the teleutospores have very short stalks. 

The anatomical changes produced in leaves beset with aecidia 
have been staled by AVakker as follows: The swelling <»f the 
leaf-petioles is due to t'nlai'.^(Miicnt of their cells; thf large 
intercellular spaces of the sjiongy iiaicinlivnia aic no lunger 

' l''c-iit/ling, Ilia III/ lira/ iJixMtrtatiiiii. Freiluir)^, I.SK'J. 

-Fuuinl !il(jng witli the ArciiliHin at MontroHc (Sootlaml) l>y I'ml. .1. \\ . II. 
Trail. (Kdit.) 



348 UREDINEAE. 

present : the palisade layer is doubled, and rupture of the 
epidermis takes place ; chlorophyll-formation is suppressed, the 
cell-sap becomes yellow, and starch tends to accumulate. 

P. dispersa may cause serious damage to wheat and rye ; P. 
ruhigo-vcra, also on barley and oats. The spore-patches are 
found on stalks and leaf-sheaths more than on the lamina. The 
mycelium may hibernate in grasses, so that the fungus is not 
dependent on the aecidial stage ; for this reason the disease is 
not easily combated. 

P. glumarum Eriks. et Hemi. Golden-rust. This species, 
hitherto generally included under P. ruhigo-vcra (D. C.) has been 
separated by Eriksson and Henning.^ Experimental infection 
on Boragineae gave negative results. 

Eriksson distinguishes the following specialized varieties of 
this species : 

A. Definite (and undoubtedly distinct). 

1. Yar. tritici on Triticum vulgare. 

2. Var. hordei on Hordeuin v^dgare (somewhat uncertain). 

3. Var. dymi on Elgmus arenarius. 

4. Var. agropyri on Triticum rcpens. 

B. Not sharply defined : 

5. Var. sccalis on Secede cereal e. 

The uredospore-sori are lemon -yellow in colour, and form 
lines on the leaf-blade which may run together and reach a 
length of 10 mm. The teleutospore-sori form long, fine, brown 
or black lines : the sori are divided into numerous chambers, 
each enclosed in a circle of curved brown paraphyses. The 
spores germinate in the autunui of tlie same year. The pro- 
mycelium is yellow till the spores are abjointed ; in this way 
it is distinguished from P. dispersa. 

P. poarum Niels. (Britain). Uredo- and teleutospores on 
Poa. According to Nielson, the aecidia occur on Tussilago, 
Petasites, and Adenostyles. Fentzling {loe. cit.) has described 
certain anatomical changes which accompany deformations due 
to the aecidia. 

P. phlei-pratensis Eriks. et Henii. This lia.s a liiberiiatiiig mycelium 
wliicli produces uredospores contiiuiously on PIdeum and probably also 
on F('xt}ica. Aecidia have not as yet heen (jl)served. 

' Ell iksson and Henniiig {loc. rif. ). 



PUCCINIA. 3-19 

p. agrostidis Fli-wi.' Teleutospores on Agrostis vulgaris; aecidium = 
Aec. aquilegiae Pers. (Britain and U.S. America). 

P. festucae Plowr.' Uredo- and teleutospores on FeAtura ovina and F. 
duriuscula ; aecidium = .lec. pendi/meni Schiiin. (Britain). 

P. phragmitis (Seliuni.). Uredo- and teleutosi»ore.s on Phraguutes. 
Aecidiuni = J'-'-, riibellic/u on liume.t <rispns and other species of Rvme.i; 
also on Rheum. (Britain and U.S. America.) 

P. Trailii Plowi-. Uredo- and teleutospores on I'liragmites rommunis. 
Aecidium on Rume.r Acetosa. (Britain.) 

P. Magnusiana Korn. Uredo- and teleutospores on Phrugmites communis. 
Aecidium on RdnUKCulus repens. (Hiitain.)- 

P. moliniae Tid. Uredo- and telento.sporf.s on J/oh'/tia coerulea. Aecidium 
(accordiiiL;- to lJostiup'.s<»iit-of-door experiments), on Orchis repens, O.raasculu ; 
probalily also on other Orchideae. (Britain.) 

P. nemoralis Juel. Uretlo- and teleutospores on Molinia coernlea ; 
aecidium (J^f. melampi/ri Kze. et Schni.) on Mdampynim prutense. 

P. australis Korn. Uredo- anil teleuto-spore.s on Molinia in Tyrol ; 
aecidium (.l'''. erectum, acc(jrding to Pazschke) on Sedum rejie.re, S. acre, etc. 

P. perplexans Plowr. Uredo- and teleutospores on Alopecurvs pratensis ; 
aecidium on Ranunculus arris. (Britain.) 

P. persistans Plowr. On Triticum repens. AtL-'ulnim = Aec. thalictri 
(Britain). 

P. sesleriae Iveiih. On Sesleria coerulea. Afiidium <>ii Jihamnus 
sa.ixitilis. 

P. Winteriana Magn." {P. .sessiUs, Schn.). Uredo- and teleutospores on 
Phrdaris arundinacea. Aecidium on Alliuin ursinum {Aec. alliatum Rbh.). 

P. sessUis Schn. (including P. digraphidis Soppitt and P. paridis Plowr.) 
(Britain.) Uredo- and teleutospores on Phalaris arundinacea. Aeridium, 
according to Soppitt,^ on Convallaria majalis, also on Majanthemum, Paris, 
Poli/gonatuui, LUium canadense and Streptopus S)nilacina. Klebahn's experi- 
ments confirm the relationship of the aeciilium nu Mnjantheinum, Convallaria, 
Poli/gonatum, and Paris. 

P. phalaridis Plowr. On Phalaris arundinacea. Aecidium {Ace. ari) on 
Aruiit ilalicnin and .1. maculatum. (Britain.) 

P. agropyri Ell. et. Ev. (Jn Agropj/ruut. Avv'n\h\ni = Arc. clcniaddis 
1). r. on (.'leinati.f Vitalba and ('. recta, etc, in Europe and Anu-rica. 

P. caricis (Srlium.) (Ihitain and U.S. America), rretlosjuires 
and iclculDspijri'S »»n .species of Carre Aecidia, accordin:.,' to 
^lai^nus, on Urllcn {Yv^. 1S5). The same aullior also believes 
that the uredo-.stage can hibcrnale. 

' l'lowrij,'lit, (Invilha, xxi., l.SU.S, p. KiK. 

- \\\v\>i\.\\\\ (Zi'itHch. f. PjUunenkrankhtiti n, 189'J) coiiliriiis I'lowrighl'.s obsc-rvu- 
tioUH on tliJH. 

•'MuKMU.s, Il'iliiijiii, |S<J4. 
'.Soppitt, J oil null III' liiitamj. IS'.M). 



350 



UREDINEAE. 



Stems, leaf-stalks, and leaf-nervatiire often undergo one-sided 
thickening and curvature as a result of formation of aecidia. 
Wakker thus summarizes his observations on the anatomical 
changes in these malformed parts of Urtica : there is an en- 
largement of cells and an increase in the number of large inter- 
cellular spaces ; no formation of collenchyma, interfascicular 
cambium, and chloroph}dl ; a diminished formation of calcium 
oxalate ; an orange coloration of the cell-sap ; and a distension 
or rupture of the epidermis. 




Fio. ISo. — Puccinia cancis on Stliiging A'cttlc. The aecidial cushions have caused 
swelling and distortion of steins and leaf-stalks, also swollen outgrowths on the 
leaves, (v. Tubeuf phot.) 



Klebahn and Magnus believe that there is a Puccinia on 
Carex acuta and G. Goodcnoughii related to an Acciditcm on 
Bibes Grossularia, R. riibrum, and R. aurcum ; also a Puccinia 
on Carex riparia with an Aecidium on Ribcs nigrum. On this 
account Klebahn ^ distinguishes Puce, caricis i., ii., and iii., 
agreeing respectively with P. Pringshcimiana Kleb., P. caricis 
(Schum.), and P. Magnusii Kleb. 

P. Schoeleriana Plowr. et Magn.^ (Britain). Uredo- and 
teleutospores on Carex arenaria ; aecidia on Scnccio Jacobcica. 

1 KleT)ahn, Zeitschrift f. PJlanr.enkrankhtiten, 1892, 1894, and 1895. 
- Hedifii/ia, 188(i. 



rurciNiA. 351 

P. sylvatica Schroet. (Britain). Uredo- and teleutospores on 
Ca.rr.r ; aecidia un some Compositae. Schroeter ^ regards an 
Aecidium on Taraxacum ojffichudc and Senccio nemoinisis as 
related to tlie teleutospores on Carex hrizovh'n and 0. prarcar. 
Klebahn -' reared aecidia on Tarcucacum after infection with 
teleutospores from Carex arenaria ; E. Fischer obtained aecidia 
only on Tara.raann offlcinah. Dietel ^ regards Aecidium 
Bardanac on Arctium Lappa as related to this species. 

Attacked leaves of Taraxacu.7fi are frequently much deformed, 
stunted, and twisted. Those of T. officiacdc have orange-red 
warts on the lower surface, and there Fentzling {\oc. cif.) found 
both spongy and palisade parenchyma increased and more or 
less deformed, the cells being elongated and enclosed in 
hyphae. 

P. leucanthemi Pass. According to E. Fischer, tlio meilo- and teleuto- 
spores are found on Carex montana; the aecidia {Aec. leiicanthenti) on 
Clirysanthemum Lencanthernum. 

P. tenuistipes Rostr. Uredo- and teleutospores on Care.r muricata ; 
aeciilia on (''■„tiinre<i. 

P. arenariicola Plowr. et Ma;L,Mi. Un i'arex aremirin ; aecidia = Jec. cent- 
aureae on ('. niynt. (Britain.) 

Ed. Fischer found tiiat the sjiecies of Puceinia on Carex montana (one 
with its aecidia on Centavrea Scahioso, the othei- on Centaurea montana), 
were specifically different. 

P. limosae Magn. Uredo- and teleutospores on Care.r limosa ; aecidia 
on L'/Hiiniiiliiii tliT/rxifoh'a and L. culgitris.^ 

P. extensicola Plow. (Britain.) Uredo- and ti-leutospores on Carex 
I'.rti'Hxit ; aecidia on Axter Trijjuliain. 

P. dioicae Magn. (Britain and U.S. America). Uredo. iuid teleutospores 
on Carex dioii'ii and ('. Duridlinna ; aecidia on <V/-.s/>o/i (according to IJostrup 
and Schrf)eter). 

P. firma l)iftel. Teleutospores on Carex Jirma; aecidia on BeUiiUastntm. 

P. vulpinae Schroet. Uredo- and teleutospores ou Carex ridpina ; 
aecidia on < 'lirynantheraum Tunacetum/' 

P. paludosa Plowr. (Britain). Uredo- and teleuto.spores on Carex I'tiftfunn, 
etc I'low ri/lit gives Aeiidima pedlinlarin as the aecidial form. The 
attackcil jdaiits of /'ediciilarin arc often consideiahly deformed. 

P. uliginosa Juel." l^rcdo- and teleutospores on Carex nd</aris; 

' /'i/zf Srh/f Mints. 

- Klehuhn, Zi-i/xrhri// J. J'jlfiii:nikruidfi< iti ii, ii., |S!)2. 

' Dietel, Ornttrrtii-h. hotan. Zrilnnij, 18S1(. 

* Maj^ini8, 7'nijli/. il. Xalur/orxrh. ViniitH in Miiiirhin, 1S77. 
' Scliroeter, /'i7;< Srliliniinx. 

• .liui, .Ml/roll,,!, liiil. Vtl'uxraiiH.Ak'til. Forlidinl/, \S[H. 



352 



UREDINEAE. 



aecidia {Aec. parnassiae Schlecht.) on Parnassia palustris. Spermogoiiial 
pycnidia are unknown. 

P. scirpi D. C. (Britain). Uredo- and teleutospores on Scirpios; aecidia, 
according to Chodat, = Aec. nymphaeoides on Nymphaea, Niiphar, and Lim- 
na n th em u m nymph aeo ides. 




Fig. \S6. — l'iicrii>ia suaccokns on Cirsiuni arvense. The plants are abnormally 
elongated ; the leaves have remained smaller and simpler, and are thickly beset 
on the lower side with patches of chocolate-brown uredospores. (v. Tubeuf phot.) 



P. eriophori Tliiini. Uredo- and teleutospores on Eriophonnn latifolium 
in Siberia and Denmark ; Eostrup gives as the aecidial form Aec. cinerariae 
Hostr. 

P. obscura Scluoet. Uredo- and teleutospores on Luzida ; aecidia on 
Bellis perennis (Plowriglit). (Britain and U.S. America.) 

P. septentrionalis Juel. Uredo- and teleutospores on Folygornnn vivi- 
parum; aecidia (^-lec. Somriierfeltii) on Tludictrum alpinum in Scandinavia, 



PUCCIXIA. 353 

Iceland, Greenland, and Switzerland. Juel .states that this is the only 
heteroecioiis Pucrinia whose uiedo- and teleutusijores inhabit a <li(.otyle- 
donoiis plant. 

(2) Accidia are absent ; jji/cnidia, uredosporcs, and tdeutosporcs 
jleveloped on the same plant. {Braehypuccinia, Schroet.) : 

Puccinia suaveolens (Pers.) (Ilritain and U.S. America). 
ihn' luiiii (111 Cirsium "i-rensr, and a second on Centaurea Cyanus. 
rvcnidia and uredospores appear first, then teleutospores develoi» 
amongst tlie later-formed uredospores. 

Tile shoots and leaves of attacked plants are permeated with 
mycelium and rendered conspicuous by their elongated shape, 
lighter colour, and smaller, less lobed, softer leaves (Fig. 186). 
Diseased plants bear no flowers. Wakker on investigating the 
diseased stems found : non-development of those sclerenchyma- 
sheaths of the primary tissues situated towards the interior of 
the stem, whereas those towards the outer side show secondary 
thickening ; irregularities occur in the interfascicular cambium, 
so that the phloem becomes abnormally developed and propor- 
tionately more extensive than the wood, it may also be divided 
by a band of sclerenchyma. 

P. hieracii (Schuni.) (Britain and U.S. America). On numerous C'om- 
positae, e.g. Carlinu, Cirsium, Carduus, Ceataurea, Leontodon, Scorzo/iera, 
Crepis, Hieracium, Cichorium, etc. 

Plowright distinguishes two allied species on Compositae, viz. /'. 
ceataurene, Mart, on Centaurea nigra, and P. tarcLvaei Plowr. 

P. buUata (Pers.) (Britain and U.S. America). On Umlielliferae, <:g. 
Ajti'tiii, Pi'trosdinum, yElhusa, Selinum, Coniinn, Anethinn, etc. On culti- 
vate<l s|jecies {e.g. Parsley, Dill, Celery, etc-.) it may prove troublesome.^ 

P. oreoselini (Strau.ss). On Peucedannm and Sesdi. (U.S. America.) 

P. helvetica Schroet. On Asperida taurina. 

(3) Uredospores and teleutospores alone Inoien. The related 
P!/cnidia and aecidia have either not as ijet been frond, or il>> 
loit r.rist. ( Jfiuii iHircinio , S''Ji roet.) : 

Puccinia sorghi Sihwrin. (Pnee. viai/dis i'.i'r. ). Tliis rusi «.t' 
Sorgkinn and Zio Mais occurs in Anu'rica, Italy, (lermany, i-lc 
Th»; leaves liecome more or less be.set with little pustules, in 
which the .sori of uredospores or teleutospore.s are contained 
(Kig. 18 7-1 89). 

P. purpurea ( 'ki. On S<>rg/i"iii rii/g>iir in India, au'l /"' in Afri<a. 
' l)e>ii:ri|)li(in anil li^,'infM in .\'. ■/. Aijrir. J:'x/»r. SOtfioii Jt'tjiorf, IS'.II. 



354 



UREDINKAE. 



P. elymi West. (Rostrnpia elj/mi Lagerh.). On Ehjmvs arenariv.s and 
E. mollis. 

P. Baryi (Berk, et Br.). On Brachy podium in Europe and Britain, 
Bambtisa Thouarsii in India, Andropogon, etc., in America. 

P. longissima Schroet. On Koeleria cristata in Germany ; A'. Berythria 
in Egypt. 




Fig. 187. — Puccinia sorghi 
{Puce, maydia). Portion of 
Maize-leaf showing spore - 
patches, (v. Tubeuf. del.) 




Fig. 189. — Puccinia sorghi. Three teleutospores and two 
uredospores. One of the latter exhibits the tiny point-like 
projections of the membrane, (v. Tubeuf del.) 




Fig. 188. — Puccinia. sorphi. Section of leaf of Zea Mais filled with mycelium. 
The epidermis is ruptured by a spore-sorus. At one end there are still the remains 
of a uredospore-sorns and a few uredospores. (v. Tubeuf. del.) 



P. paliformis Fuck. On Koeleria cristata. (Britain.) 

P. anthoxanthi Fuck. On Anthoxanthum odoratum. (Britain.) 

P. gibberosa Lagerh. On Festuca sylvatica. 

P. angustata Peck. On Scirpus and Eriophorum. (U.S. America.) 

P. junci (Strauss). On Jiincus. (U.S. America.) 

P. oblongata (Lk.). On Lvzula. (Britain.) 



I 



PLCCIM.A. 355 

P microsora Ki/in. On Carex vesicaria. 

P. caricicola Fuck. On Carex supina. 

P. allii (D. (.'.). Onion-rust. (U.S. America.) 

P. iridis (I). C). On Iris. (Britain.) 

P. veratri Xiessl. ( )n Veratrum nUnnn and V. viride. (U.S. America.) 

Puccinia pruni I'ers. riuiii or Prune Paist. [This is a 
coiiiinou species in both Europe and the United States ; it 
attacks almost every kind of cultivated drupaceous fruit, includ- 
ing prune, plum, peach, nectarine, apricot, cherry, and alnmnd. 
The uredospores are brown, the teleutospores darker, and both 
are as a rule found only on the under surface of the leaf 
(Fig. 82). The leaves first show yellowish or reddish spots 
which rapidly enlarge and darken in colour till rupture of the 
epidermis takes place, and they rapidly dry up. The fruit is 
thus altogether lost or much injured, while ripening of the wood 
is more or less interfered witli. 

The remedies suggested are : sprayings with modified eau 
celeste, or ammoniacal copper carbonate (see p. 69)].^ (Edit.) 

P. cerasi (Bcreng.) C'herry-ru.st on l^ntmis Verasus, P. Ami/ijdalus, 
and /'. Persica. 

P. oenotherae Vize. On American species of Oenothera. 

P. giliae. Haik. On Pldo.r and Gllia. (U.S. Americ<\.) 

P. tanaceti I). C. On Tawuetum vulgare. (Britain and U.S. America.) 

P. sonchi iJol). et De.sm. On Sonchus. (Britain.) 

P. endiviae Pa.s.s. On Cichoria Endivia in Italy. 

P. carthami ( 'orda. On Carthamns tinctoria. 

P. balsamitae (Strau.ss). On Tanacetum Dahamita. 

P. picridis Haszl. On Picris in Hiuigary. 

P. bistortae (Strau.ss) (Britain and US. Anaiica). On Polifgomnn 
Disturtn and /'. fici/j'innn. The teleutospores have no j)a])illa on their 
fjerm-pores. Soppitt (O'revdlea, 1894) claims relationship between this 
species and an Aecidium on C'onopodiuni denudatum {Aec. hunii {])). 

P. mammillata Schroet. (U.S. America). On Poli/gonHin Bixturtn. The 
upper cell (if I lie teleutospore ha.s an apical thickeninjj;. 

P acetosae (Sclnuii.). On /linnf.r ArctOKa, [{. an'/o/t<t, and /L Aeetosella. 
LudwiLT >;iys it IijIm inatcs in tin- uredo-form. 

P. polygoni I'ti.s. (Iltitiiin and U.S. Ameiini). ( >n Pnli/cfonvat'. 

P. rumicis scutati (D. ('.). ( )n I'objgoneae. 

P. oxyriae Kuck. (Britain and U.S. America). On Oxi/rin. 

P. castagnei '["liiini. On Apiuiii (/r<tfeoleii.'< in France. 

P. cicutae i-isdi. ( )n Cirnta viroxa. 

' riiTcc {.lonriKil »J .M ijidloiiy, \ii., p. .■t.")4) ^ivcM an account of tliJH di8eiu«e i\n 
foiuiil in (alifoiiiia, ami dcscrilKs application and icmuUh of various renicMlii-M. 



356 UREDINEAE. 

P. stachydis B. C On Stacliys recta. 

P. argentata (Schultz). On Impatiens. (Britain and U.S. America.) 
P. Berkeleyi Pass. On Vinca. (Plowright di-stingaishes also P. vincae.) 
(Britain.) 

(4) Uredospores absent or only rudimentary. The other spore- 
forms — lyycnidia, aeeidia, and teleidospores — elevelop on the same 

host -plant. {Pvceiniopsi>i. Schroet.) : 

Puccinia tragopogonis (Pers.) (Britain). On Tragopogon, 
Scorzonera, Fodospermurn, and Galasia. The leaves of diseased 
plants are conspicuous in spring from their slenderness and 
pale colour. 

P. senecionis Lib.^ (Britain). The mycelium inhabits species 
of Scjiccio ; it probably arises from aecidiospores, and produces 
both aeeidia and teleutospores. 

P. ipomeae Cooke. On Ipomea in U.S. America and S. Africa. 

P. bunii (D. C). On Carum Bidhocastanum and Pimpinella Sa.iifraga 
(Britain). ' 

P. smyrnii Biv^ On Smyrnum Olusatmm. (Britain.) 

P. trollii Karst. On Aconituni Lycoctonum and Trollius europaeus. 

P. Valerianae Carest. On Valeriana officinalis and Centranthus 
Calcitrapa. 

P. liliacearum Duby. On Ornithogalum, Scilla, and G'agea. (Britain.) 

(5) Teleidospores cdone produced ; they hibernate in dead host- 
remains {Micropnceinia, Schroet.) : 

Puccinia fusca (Relhan.). (Britain and U.S. America.) 
Anemone-rust. The brown spore-patches of this fungus occur on 
various species of Anemone, Thalictrum, and Pulsatillcr. Attacked 
plants of Anemone nemorosa (Fig. 190, 6 and 7) have their leaves 
much altered, the petioles being abnormally long and the laminae 
much thickened, with narrowed segments, and conspicuously pale- 
green. The teleutospore-patches form chocolate-brown spots on 
the lower surface of the leaf, and stripes on the leaf-margins. 
Flowers are rarely developed on diseased plants ; Fentzling, 
however, found flowering plants with aeeidia on the leaves ; 
three of the perianth-parts being stunted. The same investi- 
gator found a few anatomical changes in deformed plants ; in 
petioles the middle one of the three vascular bundles normally 
present was larger than those on each side of it ; in the dis- 
eased lamina the parenchyma-cells were enlarged, while inter- 

iDietel, Hedwigia, 1891, p. 291; also Zeitschrift f. PJlanzenkrankheiten, 1898, 
p. 258. 



PrCCINIA. 



357 



cellular spaces were more numerous and also larger. Other 
minor differences are also given, but there seems to have been 




^■^ 



Kid. 11)0. — Aneinont-Rutl. 2 and ;{, Noniiiil |ilttiit.H of Aixtmoat rununruloidtt. 
4, Aiciiliain itunctntum cm Ancmont rananeuluititf ; iiucldlu on Ihu lowvr Hiirfikco 
of the leaf; the ]>lantH iirc iil>noniiiilly ulunKi'tod, and tliu luitf'Ho»;iiit'iit.H nrv 
MniiillLT. <i iinil 7, I'lii-einm j'luai nii .Inniiour itrmonmi ; tlu> pliintH rein <lli mniill, 
U IH i-<>niplutvly duforniud, 7 |>itrtiully. I mid .'>, An-ulium /riK-ix/xi iiiiiiu on 
Aioiituiie /lemoi-OKt ; thu |>liintf< iiri- itlmornialty c-loiiKMtc-d and tliv luiif iict{nii.-ntH 
»nmllur. (v. Tubouf del.) 



358 



UREDINEAE. 



some confusion between plants infested with this Fuccinia and 
those with species of Accidvmn. The changes induced on 
anemone by either Aecidium Icucos'permum D.C. or Aec. pundatum 
Pers. are quite distinct (Fig. 190). 



y 



^..,«:->;^-^r-..->f^J^ 



^^fi.jS^^A.': ■> 



SA 






\ i 






'&-' 





Fig. 191. — Pvxcinia ribis on Red Currant (Ribfs ritbrwa). Teleutosisore-patches 
on leaves and fruit, (v. Tubeuf jihot.) 



P. singularis Magii. On Aneino7ie ranunculoides in Austria and 
south-east of Europe. The teleutospore germ-pore is situated at the centre 
of the lateral wall of the lower cell, thereby distinguished from that of 
P. fusca. 

P. atragenis Haussni. On Atragene alpina. 

P. thalictri Chev. On species of Thalictrum. (Britain and U.S. 
America.) 



PUCCINIA. 359 

p. Fergiissonii Berk, et Br. On Viola pabij^tris, etc. (Britain and U.S. 
America). 

P. alpina Fiuk. On Viola hi flora. 

P. geranii-sylvatici Karst. On Geranium sylcntii-Hin} (U.S. America.) 

P. Morthieri KiJrn. On Oeranium. 

P. Holboelli (Horn.). On Arahi.^ Ilolhodli and Eri/siiiiuiii narci.i.'^ifuliuni 
in |)ciiiiiark and U.S. America. 

P. drabae K'lid. On Draha aizoi</ej<. (U.S. America.) 

P. dentariae (Alb. et. Schwein.) On Dentaria bulhifera and IJ. 
enneaphylla, causing pustule-like outgrowths on the leaves. 

P. ribis (D. C.) Currant-rust. On Rihe.'i rtibrum, li. nitjrum, li. alpiiuim, 
R. (iroKsiilaria, and R. petraeum (Britain and U.S. America). (Fig. 191.) 

P. saxifragae Scliicclit. On Sa.rifraga. (Britain and U.S. America.) 

(P. Pazschkei Dictcl. On Sa.rifraga elatior and S. Aizoon.) 

P. rhodiolae B. et Br. On Sedum rhodiola. (Britain.) 

P. ssdi Kiirn. On Sedurn elegans. 

P. aegopodii (Schum.). On Unibelliferae, e.g. Aegopodiion, Aflr'nttia, 
and I\'aii:<liiniiin. (Britain.) 

P. enormis Fuck. On CItaerophyllum aureum. 

P. asarina Knze et Schm. On Asaruni. (Britain.) 

P rubefaciens Job. On (ialitaii boreule in Scandinavia and U.S. America. 

P. campanulae < armich. On Campamda and Ja-fione. (Britain and 
r.S, Anii-iicH.) 

P. conglomerata (Str.). (Jn ILirnogym' alpina. 

P. expansa Link. < )ii Adi'nostijles and Senecio. 

P. virgaureae (!).('.). On Solidago. (Britain and U.S. America.) 

P. cardui I'lcwr. < )n Carduus lanceolatus, and V. cri-yjii--^. (Britain.) 

P. Anderson!. B. ct Br. On Cardans heteropkyllug. (Britain.) 

P. bellidiastri {I ng.). On Bellidiastritm. (The aeeidium ^n the .same 
iinst liiloni^s ti) I'licc. jinaa Diet.) 

P. adoxae I). C On Ado.ru moschatelliiui. (Britain and U.S. .Vnurica.) 

P. betonicae (Alb. ct Schwein.). On Retonira offi<iitali.'< and Sfii,/ti/.t 
nrtii. (Britain. 

P. Schneideri Schroet. On Tlit/mus Serpt/llinu. (Britain.) 

P. scillae Bk. ( )n SrUla bifolia in Hungary. 

P. tulipae SchiiM-t. On Tulipa (lesneriaiia. 

P. Prosti .\I'>ii'4. ( )n T'lh'iia si/lr/'stri.^ and 7'. ('fl.sluini in Italy and 
Frani c. 

P. Schroederi l'a>s. < »ii .yani.tsa.t purtiiin. 

(Ij) 'I'/u' t( Irtitospons (jrrminatr on tlu living plants, ami again 
jn'oilt'rr trirnfa.fporrs. All o/hrr Jonns of sparr arr ahsrnt. (I.rpfa- 

jiiirini la ^ Sflirmt. ) ; 

Puccinia raalvacearum .Mmit. ncrtirs um varinus .Malvaceae. 

■ ll<ii-ciiiy ^.[luialt III' liiitanij, v., p. "JT I «lc'siTilif.H iind li^^iircs ii rar. h'ln'i'i mix 
oil (I'f.riiiiiiiiit II' jitt/i iiti . 



360 



UREDINEAE. 



This rust is indigenous to Chili, and was introduced into France 
about 1868, whence it rapidly extended throughout the whole 
of Europe, and during the last ten years has made its appear- 
ance in the United States. In many places it has completely 
exterminated both wild and cultivated mallows, and rendered 
the cultivation of garden hollyhocks impossible. It appears in 




Fio. 102. — Puccinia malvacearum. Mallow leaf, with teleutospore-sori. Three 
teleutospores, one germinating, (v. Tubeuf del.) 

May or June on the leaves, stems, and petioles of the host ; 
all are more or less deformed, and the leaves may in severe 
cases wither up long before the flowers appear. Sponging 
with a solution of permanganate of potash (two tablespoonfuls 
in one nuart of water), has been found an eflective remedy. 

P. Sherardiana Korn. On mallow in America. 

P. heterogenea Lager. On hollyhock in South America. 

P. anemones-virginianae Schwein. On Anemone. (U.S. America.) 



PUCCIMA. 361 

p. thlaspeos .Scliub. On TIdaspi alpestre and Amlu's hirsntn 

P. spergulae D. C. On Spergula. (U.S. America.) 

P. arenariae (Scluini.). On Alsineae and Sileneae, e.;/. cultivated l)i<ii,tl'ii.< 

hurhfitii.<. (Britain and I'. 8. America.) 

P. chryosplenii Orev. On i'hrysosplenium. (Britain.) 

P. circaeae Pers. On Circaea. (Britain and U.S. America.) 

P. buxi I). ('. On Buxus sempervirens. (Britain.) 

P. umbilici Ouej). On Umbilicus. (Britain.) 

P. valantiae Pers. On (jalium. (Britain and U.S. America.) 

P. asteris Duby. (Britain and U.S. America.) On Aster, Arteinimu 

.Ic/iiU'/'i, Cirsii'.in, >Scabiosa, Doronicvm. Plowriglit regards P. miUefolii 

Fckl. oil Aihillea as a distinct species. 

P. veronicae (Scliroet.) (Britain). -v 

P. veronicarum \). ( '. (Britain and U.S. America). |-0n Verunica.^ 

P. albulensis Mat,'n. J 

P. glechomatis D. ('. <hi O'lec/toma (Xepeia). (Britain and U.S. America.) 

P. annularis (Strau.s.s). On Teucriam. (Britain.) 

Hemileia. 

Hemileia vastatrix, Berk, et Br. Tliis occurs on the leaves of the coflfee 
plant in Ceylon, Java, and Sumatra. It causes a very destructive disease. 
Sadebeck recommends as remedies: (1) Eemoval of infected leaves and 
their sterilization liy dilute acids (jr Bordeaux mixture. (2) Sjjraying 
the beds with Bordeaux mixture, so as to kill the spores which have 
fallen there. 

Several genera which do not occur in Europe may be nicntiuned here, 
viz. : Uropyxis, Diorchidium, Chrysospora, and Sphaerophragmium ; also 
Masseella, Phakospora, and Schizospora. ■ 'J'luy cnntain but few species, 

and ni'iii- ><i piactiral iiii|ioitaiici-. 

Triphragmium. ' 

Teleutospores three-celled; one cell i.s attached to the spor<»- 
pli(jre, and carries the other two ; each cell iia.s one or nit in- 
genn-poie.s. 

Triphragmium ulmariae (Sclunn.). dh-itain.) rrednspore.s 
and lfkuLij.>ji()ic.> pioduceil on the same jdanl, tSjiirttca Uhmiriti. 
TIk' Ifdento.spore-patches are dark-limw n, ilie iiredo-sori reddish- 
yclluw, while tlie jiveiiidia (sd-caUecl spernioLinnia ) are vellnuish 

' l)iHtincti«ii, .see MagiiUM, lii r. <l. ilinLtch. ho/an. (tit., ISDO, p. I(>7. 
• .Siiilcbeck, Fofxll-iinturii'iMH. Zrltnr/triff, ISJ).'). .M. \\'ar<l, Smsiuiia/ 7'(i/" ;•--' 
XVII., ('()loinl)o, ISSI. 

•'Dietel, /inlrftt, ,t. ih iilsrh. I>i,iiui. (!>s., |s;i."., (1. .•(.!•_'. 

^ !{ililii>),'rapliy ami |{ivi.-.iiiii, l.y <;. MasMcc, Unridm, \\l.. \S'X\, p. ||| ., 



362 



UREDINEAE. 



points. The so-called aecidia are really a form of uredo-sori ; 
they occur as thick cushions and cause thickening or twisting 
of the leaves and petioles. 

T. filipendulae (Lasch.) (Britain). On Spiraea FilipendvJa. 
T. echinatum Lev. occurs on Meum ; teleutospores alone are known 
(U.S. America). 

T. clavellosum Berk. On leaves of Aralia in the United States. 

Phragmidium. 

Teleutospores multicellular, the individual cells forming a 
single series ; they show a variable number of germ-pores. The 





Fig. 194. — Pkrarjiuidhmi subcorliduni 
on a Rose leaf. The black spots are 
teleutospore- patches on the under- 
surface of the leaf. (v. Tubeuf del.) 

Fig. 103. — Triphragmitim ulmariae on 
Spiraea Ubnaria. Germinating teleuto- 
spore, with proniycelia and sporidia. 
(After Tulasue.) 

teleutospores are produced in loose patches. The aecidial patches 
have no covering, but are surrounded by club-shaped paraphyses. 

The genus frequents only Rosaceae. 

On species of Hosa : ^ 

Phragmidium subcorticium (Schrank.). Teleutospores, uredospores, and 
aecidia on leaves of wild and cultivated roses. (Britain and U.S. 
America.) 

Phr. tuberculatum J. Mill I. All the forms of spore occur <m Rosa 
caniiui. 

Phr. fusiforme Schrot. \Vhr. rosae-alpinae (D.C.)]. On Rosa alpina 
(Britain). 

Phr. speciosum (Fr.). On North Anierican roses. 

Phr. devastatrix Sor. On roses in Asia. 



' J. Miiller, " Die Rostpilze d. Rosa. u. Rnbus-arten," Ber. d. deiU.srh. 
botan. Ges., 1885. 



I'HRAGMIDirM. 



363 



On species of Pofcntilla : 

Phr. fragariastri (D. C) (Britain and U.S. Ameiica). 

Phr. potentillae (Pers.) (U.S. America). 

Phr. tormentillae Fuck. (Britain.) 

Phr. papillatum Diett'l, from Siberia. 

Phr. nepalense Barcl. and Phr. laceianum Banl. in India 

On species of lluhus : 

Phr. rubi (Pers.) {I'hr. I>n.lhosum 
Schlecht.) (Britain). 

Phr. rubi-idaei (Per.s.). On leaves 
of raspberry. (Britain and U.S. 
America.) 

Phr. violaceum (Schultz) (Britain). 

Phr. rubi-miniatum J. Miill. 

Phr. albidum (Kidui). 

Phr. quinqueloculare liarcl. 

Phr. octoloculare Barcl. 

Phr. Barclay! hietel, from Hima- 
laya. 

Phr. gracile Karl., America. 

And otiier specie.s. 

( )n Sfi ii(jiii>iiirha : 
Phr. sanguisorbae (D. ('.). On 
S'liKjuUoi-ha laii'or. (Britain.) 

Phr. carbonarium (Schlecht.) 
(IJiituiu). 'riii.s species has also 
been placed in a separate genus 
Xenofloekus. It occurs on Saii- 
fjui.sorha. LTredospores are want- 
in j^ ; the teleutospores form firm 
black crusts ; the aecidiospores 
form chains ; and the parapliyses 

are club-shaped. Diseased leaves and petioles are thickened and 
benl. Wakker's investigation showed : a slight enlargenicnl ol 
parenchymatous cells and rupture of epidernn.s on spurc-formation ; 
a (Hminution in the intercellular spaces and in InrinatiKU td 
collcnchyma and sclercncliyma ; a suppressiun <if all prndudinn 
of chlorophyll and calcium o.xalatc. 




Fig. 1115. — I'lii-iijihiiUiHM iiiiii from HuIiuji 
I'lUtiioKiig. Olio spliericil iiiiiiiiiture to- 
leutosjioro, iiiul two well-iievelopcU and 
Kurininatilig ones. (After Tulasne > 



Melampsora. 

Ti-lfntospores darU and mnccllular, in .-^oiiu' cast's multi- 
(•filular by furiiialion id' now walls, gi'iioially in a vcrtiial 



364 



UREDINEAE. 



direction ; their sori form dark spots which break out from 
beneath the epidermis. The yellow uredospores have a coat 
beset with fine spines, and are given off from sori wliich may 
or may not be enclosed in a peridium. The sori of the 
aecidium-stage have no peridium, and are known under the 
generic name of Caeoma ; they frequently occur on other hosts 
than those of the teleutospores. Pycnidia are produced in little 
yellow patches. 

Melampsora tremulae Tul. (Britain). The sori of uredo- 
spores appear as little yellow protuberances on leaves or young 
shoots of Populus tremuld. The dark-brown patches of teleuto- 
spores appear later on the under epidermis, and where they 




Jr^o' 



Fig. 196. — Cneoma pinitorquum. Section showing four pycnidia, from one 
of which {!<p) numerous conidia are being discharged. Cai/ouirt-patches are 
developing beneath tlie cortical layer, as yet unbroken. (After R. Hartig.) 



occur in large numbers, an early fall of the leaf may result. 
The teleutospores hibernate in dead leaves on the ground. In 
spring the sporidia germinate and infect young shoots of Finns 
sylvestris, producing the disease known as Cacowa i^initorquum} 
This disease attacks pine-seedlings, appearing generally on 
the needles. It is most frequent in plantations from one to 
ten years old, rarer in those of ten to thirty years, and not 
as yet observed in older. Finns sylvcstris is most commonly 
attacked, but it has also been observed on Finns montana in 
Jutland. After formation of the CVifcowr^-patches, the young 
thin shoots generally die off, but thicker ones become twisted 
at the place attacked, whence the name " pine-twister " commonly 
given to this disease. If the leading shoot be attacked, the 
seedlings may succumb altogether. The disease develops rapidly, 

' R. Hartig, Wirhfit/n Krankhtiteii d. Waldhanmc;, 1874. 



.MKLAMl'SORA. 



3G5 



particularl}' in a damp and cold sprini;, and may prove verv 
destructive if it appears for several years in succession. The 
mycelium evidently perennates in i>ine-8hoots, and produces 
new Ccu'oma-patches year after year till death of the hust results. 
It grows intercellularly especially in the rind ])arenchyma, i)Ut 
also in the mednllary rays of wood and Ijast; the contents 
of the host-cells are absorbed by means of short lateral haustoria. 




Fi(i. I'.'T. — Catomu pinitorquicm. Portion of C(«om'i-pntch(enLirged). /, Cortical 
ccUm partially absorbed or much eomijressed ; '<, basidiii from which spores (/■) are 
abjoiiitcd ill succession : the younger witli delicate walls and seiKirated by 
mcnibrunous Ltniellao, wliich disajiiicar un formation of the spore-coats (<0. 
(After a. Hartit{.) 



Tlie pycnidia are produced at end of May or lu'i^inuiiiL; of 
June, between the epidermal cell- wall and the cuticle of _i;reen 
twigs : before ])reaking out they may be observed externally 
as ligiit patches on the shoot. The 6'</ro?nr<-patches tleveloj) 
later in the second or third layer of tlie rind-parenchyma 
(Fig. 19G). In eiich patch the spores are produceil serially from 
short stalks to the number of twenty or thereabout, and ultimately 
escape about .June, when the cells of the parenchyma and 
epidermis are ruptured. At tirst the spores are connectetl 
together l)y intermediate c(;lls which are afterwards absorl)ed 
(Fig. 107). The mature spores are globose, oval, or j>olygonal 



366 



UREDINEAE. 



in shape, yellow in colour, and their outer coat is beset with 
spiny projections. The stalk-cells grow out into elongated tubes, 
after completion of spore-formation. In the vicinity of the 
scar of a Caeoma-^p^dtc\l, the twig turns brown and its tissues 
become permeated with resin, while the tissues underlying the 
patch die even into the pith. 

Hartig's ^ investigations show that this same Ifelanijjsora causes 
Caeoma laricis on the needles of the larch. Plowright - also 
produced a similar Gacoma-ioxm from Mclami^sora hctulina, and 







Fio. 198. — Mclamp.fora betullna. Teleutospore-sorus, with many of the spores 
producing promycelia and sporidia (s). /•, Mycelium ; p, parenchyma ; t, portion 
of ruptured epidermis. (After Tulasiie.) 

succeeded in re-infecting Betula alba from Caeoma laricis. 
Eostrup obtained Caeoma mercurialis by infecting Mercurialis 
with Mel. tremadae ; yet this may have happened because two 
different species of Mclavipsora occurred on the aspen leaves. 
Klebahn ^ was successful in infesting Pojmlus tremula with 
Caeoma laricis but did not succeed with the birch. 



^ R. Hartig, Allegevi. Forst. u. Jeu/d-zeifung, 1885. 

"Plowright, " Impfvereuche m. Rostpilzen," Zeitsrhrifi f. Pflanzenkrankheiten, 
1891. 
•'Klebahn, Zd('<chrift f. Pjianzenh-ankhtiteii , 1894. 



MELAMPSORA. 



367 



The patclies of Caimna laricia Hartiu/ appear as golden-yellow 
cushions on the underside of the needles. The sporophores from 
which the aecidiosj)ores are abjointed, form the centre of the patch, 
the periphery being occupied by numerous sterile threads, which 
grow out as long paraphyses ; it may so happen tliat the wiiole 
cushion consists only of these last. The formation (jf Cininna- 
patches is preceded by that of little pycnidia (spermogonia), 
which l)reak out from under the cuticle. The mycelium lives 
intercellularly, and dies after the sliedding of the Ciuoma- 
spores. 

Melampsora betulina (l'er.s.) (liritain and U.S. America). 
Uredo- and teleutospores occur on the leaves of the birch 
{lirfida alha). Plowright - found from arti- 
ficial infection that this species produced 
Caeoma laricis on the needles of Larix 
europea. A second form of Caeoma laricis 
was obtained by Hartig, both from infec- 
tion by Md. tnmular Tul. from the aspen, 
and l)y Mil. jHipulitia Jacq. from the black 
poplar. 

M. populina (Jacq.)'* (Britain and \J.^. 
Anii-riraj. I redo- and teleutospores found 
on Populvs nigra and P. hahamifera. 

M. populina. and M. troiiular are probably identical, for Hartig 
has found the same Melampsora on black and balsam poplars 
as on aspen, and in each case lie produced Caronat la r ins l)y 
means of the uredospores. Schroeter states that the Mrltnii/isn,,' 
of J'(if)i/li/s /lif/ra produces Caeoma allii of Allium. 

M. aecidioides 1>. C (Britain). Uredo- and teleutosjiores on 
leaves (jf silver po))lar (P. alha and /'. cane.^rens). Plow- 
right connects with it a ea<inna-U>\\\\ on Mereiirialis {Caeoma 
mercurialvi). Schroeter states that {\w Melampsora of Populiis 
tremnla produces Caeoma nierenrialis. 

The Mel((mpsorae of Willows were until recently grouix-il 
under a collective name, M. salicina; seveial species are now 
recognized, others require \eiilicatioii. 




Fui. 19y. — MeliihipKoiK 
iHlidiiin. Portion of a 
uredospore-soru-s. (After 
Tulasnu.) 



' K. Il.irtig, ]\'ir/,ti<i> Kntidhilliii d. WuhlLiivmi ii, \'\. \' . 

-■ l'lo« rij;lit (/or. rit.). 

'K. Hiiitif,', liolan. Ceiilralhlatt, xi.vi., Is'll; " TIk- l.iif rust i.f c..ttun\\<.«Ml»,"' 
U.S. Ihpi. o/Aijrini/tun /,'i/ir,rf, ISSS, p. ."{'.lO. 



368 



UREDINEAE. 



M. salicis-capreae (Pers.) (Britain and U.S. America). 
Uredo- and teleutosj)ores on leaves of Sali.:c Caprca and several 
other species. According to Rostrup, Cacoma cuonymi (Gmel.) 
is a stage of this.^ 

M. Hartigii Thiun.- {M. epitea Thiini.) (Britain and U.S. 
America). Uredo- and teleutospores on leaves of Salix prmnosa. 
S. dn^yhnoides, S. viminalis, etc. Rostrup regards C. ribesii Lk. 
of Bibes as a cacoma-iorm. 




Pig. 200. — Mifampsora salicis-capreae. Section through leaf of Salix Caprea] 
with a uredospore-sorus on the lower epidermis ; on the upper side a teleutospore- 
sorus is in process of development, but is as yet completely closed over. (After 
Tulasne.) 



M. repentis Plowr.-' Uredo- and teleutospores on Salix repens. Caeoma 
on Orchis maeulaki. (The Caeoma orchidis of other orchids is probably 
identical with this one.) 

M. arctica Rostr. i>n Salix herhacea, S. glauca, and S. groenlandica in 
Greenland. 

M. mixta (Schlecht). (Britain). The related Caeoma is unknown. 

Thunien also gives M. Castagnei Thuni. on S. amygdaliva. 

M. vitellinae D. C. on Salix fragilis is said by Schroeter to have its 
Caeoma on <Jala)dhus nivalis (Britain). 

The rusts of cultivated willows are very detrimental to them 

^ M. salicis-cajjreae {M. raprearum D.C. ) is divided by some authorities into 
M. farinosa (Pers.) and M. epitea (Kze. et Schni.). 

-See Thiimen, " 3fel. saJicina," AtUthei/uiigen aun d. /oi-sflirh. Versuchswesen. 
Oesterreir.h, 1879. 

•Tlowright [lac. rit.). 



MKI.AMl'SOHA. 



360 



and cause great damage. The yellow 
sori appear in large numbers on the 
lower surtace of the leaves, which 
wither prematurely, especially towards 
the ends of shoots (Fig. 201). The 
teleutospores hibernate on fallen leaves, 
hence such should be raked together 
and burnt. Sdlir pruinosa is found 
to be much more sensitive to attack 
than S. i^ruinosa X daphnoides, whose 
leaves are more hairy, a property 
which seems to protect them from 
spores. 

The following species liave only 
uredospores and teleutospores, related 
f ''in oi) a -i'onns being unknown: 

M. lini (Pers.) (P>ritain and I'.S. 
America). Flax-rust. The uredo- and 
teleutospores occur togetlier on Linn/n. 
This may inflict serious dajuage in 
Helds of cultivated tla.x. 

M. sorbi (Oudem.). On leaves of 
Films AucHparia and /'. lorminaU>i. 
L)ietel ^ has recently placed this as 
the single species of a new genus 
OchroHpora. The light-yellow spores 
are at tirst one-celled, but l)efore 
the death of the host-leaves they 
dividt' into four (rarely three) cells, 
t-aeh of wiiich gives oil' a sterigma 
with a single sporidium. In these 
jtoints the spores follow the develitp- 
Mieiit of Co/eospurium ; the spnridia, 
however, are quite dilfereiit, they are 
spindhvshaped, L'2-2r>/u long and S/x 
liroad. 



N> 



-i- 



Fl<i. 201. — Meliiiitjuoi-ii lliiiligii on Siilix pruiiwttt. Tho uppor laivos 
liavu ulruiuly wlthcrud imil ciirlud up, tho lower, thuiij^h an yot uii- , 
(.■>uiii(fo<l, iiru IwHct with tho i»iliitliku hoH. (v. Tiilxjuf .luL) 

' Jlnirfiti <l. <hnlHih. hofnii. (,'is., iSiC), ji. 40l. 
2 A 



370 UREDINEAE. 

M. ariae (Schleich.). On leaves of Pyrus <(ria. 

M. padi (Kunze et Schum.). On leaves of Prunus Padns. (Britain.) 

M. hypericorum (D.C.). On Hypericiim. (Britain.) 

M. pustulata (Pers.). On Epilohium. (Britain and U.S. America.) 

M. circaeae (Schuru.). On Circaea. (Britain.) 

M. vaccinii (Alb. et Sclim.). On leaves of Vttccinium. (Britain and U.S. 
America.) 

M. pirolae (Gmel.). On Pyrola. (Britain and U.S. America.) 

M. sparsa Wint. (U.S. America). On Arctostaphylos alpimt (also A. 
officinalis ace. to Rostrup). 

M. carpini (Nees.). On leaves of hornbeam. 

M. galii (Lk.). On (Jaliinn. 

M. (Thecopsora) agrimoniae (D.C.) On Agrimonia. 

M. vernalis Niessl. Teleutospores only on Saxifraga granv.lata. 

M. helioscopiae (Pers.). On Ev.phorbia. (Britain.) 

M. euphorbiae-dulcis Otth. 
# 

Melampsorella. 

The unicellular teleutospores are developed in the cells of 
the epidermis and form reddish patches. The patches of 
uredospores are enclosed in a peridium. 

Melampsorella cerastii (Pers.). Uredo- and teleutosjDores on species of 
Stellaria and Cerastium. (Britain and U.S. America.) 

Calyptospora. 

The teleutospores are developed inside the epidermal cells, 
and are divided into four cells by vertical septa. The aecidia 
have large peridia. The pycnidia are small and precede the 
aecidia. 

Calyptospora Goeppertiana Kiihn.i (U.S. America). The 
common disease of cowberry (Vaccinium Vitis-ldaea) caused by 
this parasite is shown externally by a very marked swelling 
and elongation of the shoots (Fig. 202). Diseased plants 
elongate conspicuously above their neighbours, and in this way 
distribution of their spores by wind is facilitated. The mycelium 
hibernates in the cortical tissues, and maintains itself for years. 
It grows intercellularly, sending haustoria into the cortical cells. 
As a result of its presence, cell-growth is much accelerated, 
and a marked thickening of attacked twigs frequently occurs ; 

^ R. Hartig, Lehrhnch d. Baumlranhheitev , i. Aiifl. p. 56 and PI. II. (The 
2nd edition and the English translation are somewhat abridged.) 



CALYPTOSPORA. 



371 



intercellular spaces become enlar*,'ed, and the contents of all 
cortical cells, except those of the epidermis, takes on a red 
colour, whereby the young shoots have at first a delicate rose- 
red colour, thouifh they afterwards turn brown. The lower 
leaves have a similar red colour, but shrivel and fall oft' early, 
while the upper ones develop normally and remain attached. 




Kill. 'IQZ. — Ciiliiptotpora GtHfrptrliana. Nuriiiiil mid iiiiilfuruicd shoutu of 
Vaccinium Vili»-ldaea. (v. Tiiboiif |>hot.) 



Shcjots infi'ctcd oni! suinmiT sIkiw the syiiiiit'ims in I he 
following year. TIu; swelliii;^ is cdiitiiu'd to (he basal part of 
a year's growth, and the ajiict's of shoots remain normal to all 
external aj)peaiance, allliough permeated with luyi-elium. llarti-,^ 
ha.s explained this by assuming' tliut tiic I'migus-myeeliuiu only 



372 



UREDINEAE. 



influences young cells attacked by it during their period of 
growth, whereas cells already in the adult condition remain 
unaffected. 

Inside the diseased shoots a well-developed mycelium will 
be found between the epidermal cells, and nourished by haustoria. 




Fig. 203. — Calyptospora Gotpptrtiana. Section through epirierniis and cortical 
parenchyma of a diseased shoot of Vaccinimn. The mycelium is intercellular, but 
swollen branches penetrate the cell-walls and become sac-like haustoria. The 
hyphae under the epidermis become considerably swollen, and give off into the 
cells either haustoria {h) or the sac-like processes (c, c), which become the mother- 
cells of the teleutospores. x 420. (After R. Hartig.) 



The spores originate from processes of the mycelial hyphae, 
which bore their way into the epidermal cells, and swell up 
inside to form spherical sacs. The cells thus entered turn 
brown, and are filled up by four to eight cells produced from 
the sac-like processes of the mycelium (Fig. 203). From each 
cell of this kind a four-celled teleutospore is formed and hiber- 
nates in situ. In spring the teleutospores emit a process through 
the outer wall of the epidermal cell, and this, after division 
by cross-septa into four cells, becomes a promycelium with short 
sterigmata, from each of which a single sporidium is abjointed 
(Fig. 204). The sporidia germinate, as Hartig proved, about the 
middle of May, on young needles of silver fir (Abies pectinata). 
By the middle of June the mycelium is distributed through 
the intercellular spaces, and forms aecidia with long white sac- 
like peridia on the under surface of the leaf (Figs. 205, 206) 
The aecidiospores escape on rupture of the peridium and the 



CALYPTOSPORA. 



373 



host-epidermis, to germinate on the epidermis of another cijNvl)erry- 
shoot. The germ-tube either enters bv a stoma, or forms an 
adiiesion-disc and sends (tut a process from this through the 
epidermis. 



°(^S^ 




F'lii. 204. — Diseased .stem of Vurcuiium in a 
Liter stiitfc than Fig. iO'.i. In each ei)idenii:il 
cell («, II) six niother-celLs have >>eeii fi)nned, 
each »ubdivide<l into four teleuto.spores. 
I'roniycelia ('■) have developed from many of 
the latter, and are in proccHS of abjointing 
otT the Hjxmdia from lateral steri(irmata. 
y 4J0. (After R. Hartij,'.) 




Fig. 205. — Cnh/ptottpo'a Gotppertiano. 
Aecidia on the under surface of needles 
of Silver Fir. (v. Tubeuf del.) 




Kiii. 20d. — Aecidiuin in a needle of 
Silver Fir (much enlarjjed). h. Series 
of aecidiospores and intermediate cells. 
'■, (icniiinatin^' aecidiospores. (.\ftcr 
R. HartiK.) 



This aecidium is also fouml on Alii<s rrfi/K'/onini in I'jiju'r 
iJavaria. 

Barclayella deformans Diet.' This lia.s ln'i'ii fouiul in the Hiiiuilava 
rf;,'ii'ii I'll iiimmIIis mill xmin;; twiLfs of /'inn Murim/n {Sinitliimi'i). 'rcicutci- 
s|)(.ri'-M)ii aiv (U'Velojted, airi)iii|iaiiii'i| \i\ (listuitiini nf tiif Imst. .\<'iiili;i 
and iiicdospoit's aif iiiikmiwii. 



' Hurcliiy, "Oh a L'liiln u/ l/n. ItimiUayd S/nnri fir." CuUulta, Is.sti ; mul 
ll>il„'i,iia, 1S5JI. 



374 



UREDINEAE. 



Coleosporium. 

The teleutospores form a soft, reddish, waxy cushion, and 
germinate m situ producing four-celled promycelia; in these 
respects they exhibit great resemblance to Auricularia. Uredo- 
spores are developed in chains. The aecidia, as yet known, 
have a distinct peridium. 

Many species infect the needles of pine trees and produce 
aecidia known by the generic name Pcridermium ; other species 
also known as Pcridermhi7n and living on bark are really 
species of Cronartium. The species here mentioned with their 
Peridermiiim-ionw on pine-needles, so much resemble one an- 
other as to be almost indistinguishable, and 
the question arises whether they ' are really 
species, or only varieties due' to difference 
of substratum — habitat-races. 

Coleosporium senecionis (Pers.). (Britain.) 
The sori are produced' on leaves and stems of 
various species of Senecio (without doubt on 
S. vulgaris, S. sylvaticus, S. viscosiis). The 
uredospores are shed in June from yellow 
spots. The teleutospores follow later on 
dark-red patches, there they hibernate and 
in spring produce a four-celled promycelium, 
each cell of which gives off a sterigma with 
one sporidium. The latter germinate on 
needles of Piimis sylvestris. A mycelium is 
formed in the intercellular spaces of the 
needles, and, nourished by means of haustoria sunk into the 
host-cell, perennates and produces crop after crop of aecidiospores. 
Hyphae are produced in such numbers that the cells of the 
needle-parenchyma are tightly pressed together, and those 
adjacent to pycnidia and aecidia turn brown, secrete resin, and 
die. The needles themselves, although filled with mycelium, 
remain on the tree till the time of their normal fall. 

Pycnidia are developed by April or May under the cells of 
the epidermis. They are little obtuse cone-shaped enclosures 
appearing as brownish-yellow spots scattered over the inner 
faces of the needles. On attaining maturity they rupture the 
]iost-epidermis and give out their conidia. 



Fig. 207. — Coleosporium 
xenccionis on a bifoliar 
spur of Pinus sylveslris. 
Peridia and scars of the 
pycnidia are shown, (v. 
Tubeuf del.) 



COLEOSPORIUM. 



375 



The aecidia are produced amongst the pycnidia on needles 
two or three years old ; they have long white peridia and 
are known as Peridermium oblong isporium Fuck. The aecidio- 
spores are yellow when mature, and originate in cliains, which 
in the earlier stages of development consist of intermediate 
cells and spores, but the former gradually disappear (Fig 208). 
The spores have an average length of oOo/x and breailth of 











I-'Ki. •lO'i. — l'i, III' iiit'ii.ii /"It, (Liihi>si„,, ..na .<.«•..'., 1...). I'ortiiiii "f uii ai-ci<Uiiiii 
with biinidia (h) (pviiig otT siKirus mid iiitcnnc-tliiitf culln (•/); uutxiile tho 
]>cri(iiiiiii (/i) other bsisidiii (■ ) with cliit>-»liuiicd uiidn forco up the upiduriiiis ; 
", the thick rnyc-elium in the leiif-i>:ireiRliyiiiii. (.\fter K. Marttg.) 

20/i; in furm they are generally Inngish-oval, few lic-ing rnund ; 
the spore-c(jat is moderately thick. Aecitliospores are capable 
of immediate germination, and ])roduce ^/"/vy/^-patches on Sfiuriit 
\>y dune. 

The ured<jspores iiave an average Imglh of 'JS-.'i/i, aiid 
breadth \^>\tfx\ tliev are generally ol)long, with a moderately 
thick coat Im'scI with '^piiiv warls. 



376 UREDINEAE. 

Klebahn and Fischer^ assert that several other species of 
Coleosporiinn produce their aecidiura-stage on Pinus si/lvestru. 

C. euphrasiae (Schum.) (Britain). Uredospores produced from 
reddish-yellow, teleutospores from orange-red patches during 
July and August on various RMnanthidau' {Rhinanthus major, 
B. minor, Bartsia Odontites, and Eiqjhrasia officincdis). Tlie 
spores from Rhinanthus germinate on needles of Finns syhestris 
and produce an aecidium called Pcridermium Stahlii Kiel). 
The aecidiospores of P. Stahlii average 26m in length, 19"5m 
in breadth, and are round or shortly oval, with a coat and 
markings finer than those of P. oMongisjJorinon. The uredo- 
spores average 22/x x 15"5y«; they are irregular and somewhat 
angular, witli a thin finely marked coat. 

C. melampyri (Eeb.) (Britain). Uredospores on Melam- 
l^yrum (certainly on M. pratcnse). The aecidia — Peridermium 
Soratieri Kleb. — follow after a year on needles of Pinus sylvestris. 
The spermogonial pycnidia alone are developed in the summer 
of infection. 

C. tussilaginis (Pers.) (Britain). This Colcosporium is found 
all summer on the underside of leaves of TvssUago farfara, 
the uredospores forming yellow patches, the teleutospores darker- 
coloured ones. Aecidia are produced on needles of Pinus 
syhestris, and are known as Peridermium Plowrightii. Pycnidia 
and aecidia are formed in the summer following infection. 
The aecidiospores average 25"5ya x 19// and are shortly oval 
or round, with coats and markings more delicate than those 
of P. Stahlii. The uredospores average 26 /m x 1 9/>i and are 
roundish oval with somewhat firmer and thicker coats than 
those of C. eu2)hrasiae. 

Klebahn's infections of Petasites with aecidiospores from Pinus 
gave no result. 

C. inulae Kunz. Spores of this obtained by Fischer - from 
Paula J^inllaitfii and /. Helenium produced Peridermium Klelcdini 
Fisch. on needles of Pinus sylvestris. 

C. sonchi (Pers.) (Britain and U.S. America). Klebahn 
considers this as a provisional species including a number of 
imperfectly investigated forms whose uredo- and teleutospores 

^ Berichte d. (leuUch. hotan. Ges., 1S94 ; Zcitschrift f. Pflanztnh'an'kMiten, 1894, 
and 1895, p. 73. 

-Botan. Centralhlatt, Lix., 1894, jj. 1. 



COLEOSI'UKILM. 37 < 

occur on various species of Sonchvs (without doubt on S. 
arvensis). Aecidia are unknown. He relates it to Ftridrrminm 
Fischrri Kleb. on needles of Pinns syhestris. 

C. synantherearum Fr. A provisional collective name for 
aecidia on Ad- mist ah s, Pctasite^, Caadia, Seneeio, etc., the life 
history (if which is as yet unknown. 

C. campanulae (Pers.) (liritain). Uredo- and teleutospures 
on C'anipanulaceae (Campa/wJa and Pltjjtiiiino). The aecidial 
form is Fcridcrmium liostrvpii on pine-needles. 

C. pulsatillae (Str.). Uredo- and teleulospores on Ancmoic 
Fidsiifdiii and A. pndrnsU. Aecidia unknown. 

C. ipomoeae (Schwein). Uredo- and teleutospores on species 
of cultivated Ipomoin in United States. Aecidia unknown. 

Fischer^ obtained pycnidia on needles of pine by infection 
with a Coleosiporiiim from CamiKiindu Trachclhim. 

Chrysomyxa. 

The teleutospores are formed ulostdy together in yellow sori ; 
each spore consists of an acropetal series of cells, the distal 
one of which, without leaving the sorus, germinates to produce 
a promycelium of several cells. Uredospores are not always 
present. The aecidia have W(dl-develoi»ed peridia. 

Chrysomyxa rhododendri (D. ('.).'- This is a common rust 
on the Alps wlieic the A\\A\\v-\-i)>iit {JUiododindron fcrnniincaiii and 
It. In/'sidinn) occurs. humetUately after the break-up of the 
winter little dark-red cushions of this rust appear on tlie under- 
side of the leaves. These contain the sori of teleutospores 
alri-ady partially developed during the ])revious autumn, and 
n(»w, after hibernation, ready to increase in si/(,' and ii> rupture 
the host-epidermis (Fig. '21]). The teleutosjiores so exposetl 
germinate without leaving tlie sorus, and ]irotluce four-eelled 
promycelia, witli sterigmata, from eaeli of wliith .i singU' 
spori(Hum is aljjointed. Tlie sporidia make their eseajie in 
Juiu', ami alighting on the unfoidini; needles of the sjiruce 
{J^ura I'xcclaif), they germinate at once and jiroduii- .lirit/imn 
uhiitinum, the blister-rust of tlu' spruce (Fig. I'll'). 

An intercellular mycelium is develojted in the spruce-needles, 

^ llulan. Cuifrn/hfiit/, i.i\., lS!t». 
■-I)i- Hiuy, Ji'iftni. Z'ittiiKi, IsT'.t. 



378 



UREDINEAE. 



and small yellow pycnidia are produced during July or 
August. The aecidia follow from August till September, 
occupying yellow zones on the otherwise green needles ; their 
white peridia project as much as 2 mm. above the surface of 
the needle, and dehisce by rupture of the apex. The aecidiospores 
are formed in large numbers and, carried by wind, reach leaves 
and shoots of alpine-rose where they immediately germinate. 
The resulting mycelium produces in September yellow clusters 
of uredospores on brownish spots on the lower epidermis of 
the leaves, and on the bark of last year's shoots (Fig. 210). 







Fig. 209. — Clu-ymmyoM rhndndendri. Twig 
of Rhododendron hirsv.tinn with sort of uredo- 
spores on the lower epidermis, causing dis- 
coloured spots on the upper, (v. Tubeuf 
del.) 




Fig. 210. — Chrysomyxo, rhododendri on Rho- 
dodfiidron ferrugineum. Uredospore-sori in 
September as elongated white stripes on the 
stem below the leaves, (v. Tubeuf del.) 



The uredospores are yellow and ovoid, with granular protuber- 
ances on their coats ; they are developed in series from the sori.^ 
The disease may be further propagated during the same year 
Ijy the uredospores. In districts where spruce does not occur, 
it is probable that these spores hibernate, and in the following 
spring produce germ-tubes which infect other alpine-rose leaves. 
It frequently happens that whole forests of spruce are so attacked 
by this fungus that many of the trees retain only a few 
healthy needles. Diseased needles die and fall in the summer 
of attack, so that the trees may be almost wholly stripped, 
and thei'eby suffer considerable damage. 

Chr. ledi (Alb. et Scliwein.)^ (U.S. America). This fungus 

1 Raciborski regards the Uredo as a Caeoma-iorm. 
- De Bary, Bofaii. Zeittnir/, 1879. 



CHKYSOMYXA. 



379 



occurs on Ledum palustrc. It is difficult to distinguish tioni 
the preceding species, and causes the formation of similar aecidia 
on spruces in Northern Germany and other parts where BJiodo- 
dendran is not indigenous. Its uredospores are also capable 
of hiljernating and of propagating the fungus where spruce is 
absent. 

Chr. himalayensis IJarcl. occurs on leaves of JHuidndcitdwn 
arhorcuht in thu Himalaya. 




Fn;. 211. — Chri/nomyxa rhodoU-ml ri . Teleuto- 
.si>ort-soru8 which has ruptured the lower epi- 
dennis of a leaf of Rhododnnlion hir.uitdm. The 
teleutospores are pluricellul:ir, :ind one of them 
ha.s germinated, K'i^'in*? "• promycelium with 
steri^iiatii, from which little sporidia are being 
abjointed. (After l)e Hary.) 




Flii. '21'2. — Cliri/soiiii/xii iiKxloit' lulri 
on Spruce. The needles are beset 
with aecidia; discoloured imrts of 
them are shown black, the nmnially 
green being left white, (v. Tulieiif 
d-1.) 



Chr. abietis (Wallr.).! Xeedle-rust of si>vncc. This is puiasiiic, 
nil ihc spruce {J'irrii cjxclsa), and is found on the Alps up to 
an elevation of over 1700 metres. .Mmjui ihc l)egiuniiig «if 
May the hilx'rnatiuLr teleutospores produce promycelia and 
sporidia. 'i'he latter genuiuate at once, and the germ-tubes 
make their way througli the epidermis into young unfoltling 
needles. The myeelium is well-developed and lives iiiter- 
cellularly, sending haustoria into the host-eells ; it cuiiiains 
yellow oil-drops, so that liy tlie eml of .lune needles contain- 
ing it exhibit yellow-coloured strijies. For the remainder of 
the year reddish-yellow eh^ngated teleutospore-cushions are 



' M.iss, linhin. Z'i/ilii;/, ISJi.'); />/. /:oif/,i/\f'iiriil> il 'I. ihiltitrhrn ConifVrtll. |S69. 
NVillkoimii, />/. ),ilkr<jMr(j/,iM,l„„ F.inil. ,/,, M'(i/'/. s, 1 S(j.S. 



380 



uredineap:. 




formed, and in this condition the fungus hil^ernates, to develop 
further in the following spring. It is only in very dry cold 
winters that the needles dry up and fall off; as a rule they 
remain on the trees. About the beginning of May the spore- 
cushions break through the epidermis and give oft' multicellular 
teleutospores, which are as a rule branched. 
Thence arise the four-celled promycelia, with 
sterigmata, from which a single sporidium is 
abjointed. 

Diseased needles- remain green except in 
areas inhabited by mycelium ; yet needle-cast 
soon follows liberation of the fungus-spores. 
Starch is laid up in large quantity in diseased 
needles during the first summer, but is com- 
pletely used up again by the mycelium for the 
formation of the teleutospore-patches. Spruces 
may suffer considerably from loss of foliage 
induced by this fungus, yet the risks are by 
no means so great as in the case of Chryso- 
myxa rltudodcndi-i where the whole existence of the plant is 
endangered. 

Uredospores are unknown for this species and an Aecidium 
stage has not as yet been discovered. Eeess has shown experi- 
mentally that the teleutospores germinate directly on spruce 
without intervention of an aecidial stage. 

Chr. piceae Bare. On needles of Picea morhida in India. 

Chr. empetri (Pars.) (Britain and U.S. America). Uredospores on 
Empetrum nigniin. Caeoma empetri (Pers.) is the aecidial form. 

Chr. pirolae (D. C.) (Britain and U.S. America). Uredo- and teleuto- 
spores on Pyrola. Aecidia unknown. 

Chr. albida Klihn. On Rubus fmticosus in Germany and U.S. America. 



Fig. -213.— Cluysomi/j II 
nbictis on Picea cxrilsn. 
The sori occupy the 
middle portion of each 
needle, which is in cou- 
seqvience yellow, while 
the apex and base are 
still green, (v. Tubenf 
del.) 



Cronartium. 

Teleuto.spores unicellular and remaining attached together 
in the form of a long coiled process; they germinate in 
situ and give off sporidia. The masses of teleutospores arise 
on the place formerly occupied by a uredospore-sorus. The 
ovoid uredospores are abjointed from .short stalklets enclosed 
in sori with a short peridium. Aecidia are developed on other 



CRONARTilM. 



381 



host-j)lants, and several species produce blister-nist on tlu- bark 
of species of pine. 

Cronartium asclepiadeum (Willd) (U.S. America). I'redo- 

and teleutu.sjjurt'.s (tccur ou Cijnanchum Vincctuxicvm (perhaps 




Fig. 214. — Cronartium ugcUjiindmm uii Cimanchum VinretoxIcHm. The uredo- 
sori show as spots, the teleutospore-sori as processes on the leaves, (v. Tubeuf 
del.) 



also on Gentiana asdcpiadca). The aecidial stage, known as 
Feridcrmium Cornui Eostr. et Kleb. produces a blister-ru.st on 
the bark of Pinus sulvestris. 




Kkj. 21.0. — Viomirtiuui uKrUjiiitJ- urn. Scctiun i>i n 
Cynnarhaiii luiif. The Iciif-paruiichyiiia i« jH-TincatLMl with 
niyceliuiii, and MOii are tonnuil on tho lower opiduniii.s. 
A, nredo-Hiiriis ; B, telLMitDspore-Huriis, many 8p<irL'n nf 
which have (;enninatc<l and dfiven ulT jironiycelia with 
HjMjridia. (v. Tuljcuf del.) 



lirown spots may be t'diiiul mi ihe It-avt-s ut' ihc ('i/mnii /i imt^ 
during ■h\]y, August, and SL-pli-iiibcr ( I'iu'- -II). On exatiiina- 
lioii dl" the sjxits with a lens, the hMt-fpidmiiis will be t'diniil 

'A vuiy coiimuMi iilimt in Kmnpc tli<iu>,'li not intli^ji'MouH tn I'.ritain. (Kilit.) 



382 UREDINKAK, 

pierced by a circular opening under which lies the yellow 
uredospore-patch of the Cronartium enclosed in its peridiurn. 
The ovoid yellow uredospores have a coat beset with short 
spines and are abjointed singly from short cylindrical sporo- 
phores (Fig. 215). From the uredo-sorus there next arises a 
protuberance which lengthens till it forms an elongated slightly 
curved brown cone or column consisting of cylindrical teleuto- 
spores firmly built together (Fig. 215). The teleutospores 
germinate without becoming detached from the mass, and 
produce a four-celled promycelium with small sterigmata from 
which globular sporidia are algointed. The sporidia on reach- 
ing the branches of Scots pine produce in its bark at first 
pycnidia, later aecidia. The pycnidia (spermogonia) give off 
yellow drops of liquid with a characteristic odour. The 
aecidia are yellow thick-walled sacs ; their spores are set free 
in spring and infect young plants of Gynanehv'in. 

Since the sporidia of the Cronartium-^idigQ are shed by 
September, the fungus would seem to hibernate only in the 
form of mycelium in the branches of pine. 

The effects of this fungus on the pine will be considered 
along with those of Pcridermium ■pini, another blister-rust 
of pine closely resembling this species (p. 411). 

Cr. ribicolum Dietr. Uredo- and teleutospores are developed 
towards the end of summer on leaves of various species of 
Rihes (e.g. Rihes nigrum, riibruTn, aureuin, aljnnum, sangiimcum, 
americanum, rotundifolium, setosuvi, and Grossularia). The 
aecidium-stage {Peridermium strobi Kleb.) forms the blister-rust 
of the bark of Weymouth pine {Pinus Strohus). Pycnidia 
appear in the summer of infection ; the aecidia a year 
later. Externally this bark-rust resembles that of Peridermimn 
Cornui and P. pint on the Scots pine. It may cause con- 
siderable damage to Weymouth pine both in nursery and 
plantation. ^ 

It is probable that other two forms of Aecidium are identical 
with this, viz., that on Pinus Lambertiana in America, and 
P. Cemhra especially in Eussia. 

Cr. flaccidum (Alb. et Schwein.) (Britain and U.S. America), 
Uredo- and teleutospores on Paeonia, causing the leaves to dry 

^Magnus [Gartenflora, 1891) has pointed out that both the Cronartium and 
the Peridermium are unknown in America, the home of the Weymouth pine. 



CRONARTILM. 



383 



and curl up. In some districts very conanon. Aecidial stage 
unknown. 

Gymnosporangium. ' 

Teleutospores bicrllular and furnished with stalks which have 
gelatinous walls, so that the spores come to form part of a 
gelatinous mass.- The first-formed teleutospores are thick- 




Flt;. 210.— 6'i/mjio/i/)0.<((i</tiuii cla,<i,i<u/uiii,i . I, .', .;, .M«gu.-> iii nctcliituiiL-iit of 
the- MiKjru-uusiuon.s. I,, Ci, G, Isolated sfMjre.s (enlarged) ; .< is tliin-coiited, the 
utliers are thick-coated. 7, Germinating 3i)ore with proniycelium abjointiiii^ 
8i)oridia (s). :>, A germinating Hporidiuni. (After Tubeuf.) 



walled, the succeeding ones arc thiii-\v;dlt'(|. I ' redospore.s do 
not occur. The aecidia have a tliick peridium. The teleuto- 

' V. Tubeuf: (\) Ctntrnlhlntt J. Bitkltr. ii. /'nriisif, iiLinuli , ISiH ; witli ii leviow 
of the current Literature. ("J) " Inftctioiiin niit < iyniMii.s])oraiiL;iuni." Fursf/ir/i 
iiaturirisi. X< ils<hrij't, l.S!)."i, p. 7>">. NN'otrnli-, " .\niiti>ini.silie Uiit»r.su<'liunj,'rn <1. 
(lurch <!yimio.s|)(ir;ingiuni-Arten hervnrgenifcm ii .Missbihluiigen," idem., l^'.'l. 
American Literature, see j). 40L 

-The ^ehitinou.>< BuliHtance is ohviouHly \\'eU-n(hi|ite(l t<> al>sor!> rain-water 
and HO facilitate germination of the teleuto»|iores in ^illt ; the H|M)ri(lia pro- 
(luieil are then carried nil" liy ruin or lilierated after tlie cUMhion.s diy again. 



384 



UREDIXEAE. 



spores grow on needles and twigs of Coniterae, the aecidia on 
the leaves of various Eosaceae (Poraaceae). Five species occur 
in Germany, hut there are many in America. 

Gymnosporangium clavariaeforme Jacquin. (Britain and 
U.S. America.) Tlie mycelium of this species perennates in 
twigs of Jimiperiis communis. Infection is brought about by 
aecidiospores. In the following year a swelling of attacked 
places is evident, and this increases till death of the host 
ensues. In spring, about the beginning of April, little light- 
yellow cone-like structures break out on the swollen places, 




Fig. 217. — Section through a swelling on a sixteen-year twig 
■of Juniper attacked by Gymnosporangium in its eighth year; 
three conical spore-cushions are indicated, also a cushion-scar 
with the scar-tissue. (After Woernle.) 




'■'■'M 

'■''m 



^ liitlilf C 



Fig. 218. — Longitudinal 
section of a spore-cushion 
of GymnosporoMoium clo- 
viii-iiifformc. Somewhat 
diagrammatic. (After 

Woernle.) 



and during rain swell up into long club-shaped sporophores, 
containing long-stalked, spindle-shaped teleutospores, some thick- 
coated, some thin. The sporophores swell and ultimately form 
a common mass in which the teleutospores germinate. The 
spores have four germ-pores, each capable of giving off a 
promycelium with pointed sterigmata producing sporidia, which 
are cast loose and distributed by wind. 

Germination of sporidia takes place on leaves, cotyledons, 
petioles, and shoots of various Pomaceae, where they may 
induce swellings or curvature, often to a consid^erable extent. 



GYMN'O.S1'OHAN(;IL'M. 



385 



Experimental infection with teleutospores of Gymnospor- 
angivm clavariarfonnc from Junijxri/s communis gave the fol- 
lo\vin<r results : 



On Host-plant. 
Cra toeffus Oryncantlm, 
J'yms communis, 
Crataegus tomentosa, 
Crataegus Oxyacantha, 

„ monogymi, 

Pyrus communis, 
Pyrus torminalis, 
Pyrus Mains, - 
Amelanchier, - 

Crataegus Oxyncantloi, 

Crataegus grandiforus, 
„ sangxiinea, 

„ nigra, 

Cydonia vulgaris, 
Pyrus Ancuparia, 

Pyrus latifolia, 
Cydonia rulgariti, 

Crataegus nigra, 

Crataegus Douglasii, 
Pyrus Aria, 
Pyrus Aucuparia, 

I'yrus communis. 



- ) 



Spore-foiin. 




Authority. 


(0 - 


- 


Plowiiglit 


/i. lacerala, - 


- 


Tha.xter. 


It. lacerata, - 


- 


Riithay. 


Roestelia (?), - 


- 


»i 


pyc-uiilia. 


- 


,, 


)> 




Oersted. 


H. lacerata x. 


- 


Tliaxter. 


11. lacerata and 


iiecidia 


\ 



J with long tube-shaj)ed .-Tuljeuf. 
[ peridia, - - - | 

rR. lacerata^ ... ^^ 

only pytiiidia, 

only pycnidia, - - ,, 

( pyeiiidia and little ) 

[ aecidia, - - - I 

/pycnidia and aecidia \ 

with long tiil)e-.-<]iaped -IVyiits.l 

\ peridia, - - - I 
I pycnidia and little \ 

\ aeciilia, - - - I 

)> V 11 >i 

only leaf-spot.s, - - „ 

no result, ... j, 

I'pycnidiaand aeciilia witii ) 

I a long peridiuni, | 



XoTK. — Uefore the relationshij) of the teleiitospore-forms was known, tlie 
iieciflia were de.sigiiated respectively: Ron-id tin lari rata o\\ Crataxjiis, R. roriiiita 
on I'l/niH Aucujiuria, and Ji. jitiici/luld on Apple. 

The most ahundaiit <^ermination of sporidia takes phice on 
species of Cralargus, and pycnidia (spernit)o;onia) may makr 
iheir appearance within fourteen (Uiys after infection on little 
ytdlowish sticky spots on leaves and shoots. Wy the time conidia 
(spernmtia) have made their api)earanct', deformation may he 
far advanced. I did not succeed either in procuring' oermination 
of the conidia, or infection hy meairs of tliem. 

•1 i: 



386 



UREDINEAE. 



The aecidia are developed about the beginning of June, and 
on Crataegus their peridia in dehiscing split up into very 
narrow lobes so as to form a bristly tuft over the mouth of 




§T3 



s ^ 



s 1> 

-s p. 



^s 



03 

o <s> 



o C S 

g o Ij 

s i< e 

s >- 



each aecidiuni. On cultivating infected plants of Crataegus 
indoors, I found the peridia to develop quite abnormally ; they 



GYMXOSPORANGIUM. 387 

may be as long as 10 ra.m. and are bent like a horn (Fig. 219). 
A similar case is described by Barclay^ in which the peridia 
of aecidia on Rhamnus dahurica were very long if produced 
in dry weather, but short if in moist weather. - 

The aecidiospores are shed during the early part of June, 
and germinate at once on the bariv of young juniper-twigs ; 
the mycelium growing thence into the spurs or branches to 
spread and hibernate. Teleutospores which germinate on 
Poraaceae other than species of Crataegus have apparently a 
normal mycelium, but produce pycnidia only, or aecidia with 




Fio. 220. — Cross-section through a swelling caused by GiimnoKjtorangUiui on 
Juniper-stem ; jxireuchyina with large cells and thin walls is present in abiiorual 
quantity. (After Woernle.) 

peridia differing from those on Cndargm. My own experiments 
on the quince and mountain ash regularly produce pycnidia only. 
Wakker^ summarizes the anatomical changes induced in 
deformed shoots of hawthorn as follows : cork, collenchyma, 
sclerenchyma, and chlorophyll are not formed, ligniticution of 
the cells of medullary rays no longer takes place, and there 
are few intercellular spaces. Interfascicular cambium is not 
formed, while activity of the intrafascicular cambium is suspended 
at an early period, so that the vessels remain incompletely 
<leveloped. Tlie epidermis is irregularly formed and liable t<» 
rupture. All parenchymatous cells iiiidcrgo enlargement in a 
radial dirt-cliDii. Starch is stored up in large (piantity, and 
the fMrmatidii of calcium oxalate is diniiiiishi'd. 

'"Oil tlie life-history of Pitrrluia roroiin/d rtir. /(///in/' /j <!'.<, " Trans, /.ininaii 
Sor., Loudon, 1891. 

-Tlii.s proljiiMy i.s the e.xphinatioii of the long nuridia olituiiied hy royrit-sth 
ami ilescril)eil hy .Miij^iiu.s ( /y< /-ic/i/* tl. nalnnri/m. nuillr. Wnin, Innthrui-k, ISD-IKJ). 

' J'rinijHh'im'x Jdhrhin-fi, IS'.VJ. 



388 



UREDINEAE. 



The anatomical changes induced in diseased plants of Jiinipcrus 
communis by G. elavariacforme were investigated by Woernle 
under my direction. His results were these: in vigorous branches, 
increased growth took place in the wood, bast, and rind ; in 
weakly and poorly-grown branches, the wood increased less in 
proportion to the bast and rind. The most marked increase 
took place in the bast, and to an almost equal extent all 
round the branches. This abnormal growth absorbs so much 





mm 



Fig. 221. — Cross-section of a tract of 
parenchyma in a malformed Juniper- 
twig. (After Woernle.) 







Fig. 222.— Radial longitudinal section 
through a zone of parenchyma similar to 
Fig. 221. (After Woernle.) 



water and plastic material that higher parts of the branch 
gradually die off, and dormant buds break out on the swelling. 
Increased growth results in increase in the number of medullary 
rays, while in the tangential section their height is increased 
from 2-10 cells to 10-20 and more; the wood parenchyma is 
also more abundant, and together with the rays frequently forms 
large masses of parenchyma in the wood (Figs. 220-223). The 
tracheae no longer follow a straight course, and numerous 
intercellular spaces appear between them ; the tracheal walls 
fre([uently become thickened and have an increased number of 



f;YMXOSPORANGirM. 



389 



fissure-like pores in place of bordered pits. The wood-elements 
in cross-section are no longer round but polygonal : the bast 
becomes very irregular, parenchyma grows rapidly, bast fibres 
remain thin-walled and have no longer a straight course. The 
mycelium tills the bast and rind, forming masses in the inter- 
cellular spaces ; it is easiest found in the tangential section. 
On the fall of the club-shaped sporophores, a scar is left and 
under it will be found a layer 
of cork many cells thick ; when 
new sporophores are formed in 
later years, they seldom break 
through the cork layer, but 
emerge through sftme new por- 
tion <if tlie biirk. 

Gymnosporangium tremel- 
loides Hartig^ on Jan'ipcrus com- 
iiLums. The sporocarps of this 
.species occur on the branches 
and needles; its aecidia — Buc- 
■sfi'Iia i^cnicillata — on leaves of 
apple {Pijras Mains), Fi/riis Aria 
and /'. Cluimaime.'qnlas. This 
Juir-'itilld is externally very like 
that of G. clavariaeformc on 
Crataegus. The markings on the 

cells of the peridium consist of somewhat wavy lines, not of 
short rod-like markings as in li. contufa; and the cells of the 
peridium are joined l»y a diaracteristic hinge-joint (Fig. 'J 24, 
19 and 20). 

'J'he mycelium perennates in ihe rind of Junijunis nuinnKiiis 
and ./. /lauii, causing thickening of the twigs and a premature 
death of the distal portion abcjve the swellings. The ehocdlate- 
V)rown velvety spore-cusiiiuns l)reak out between th*^ bark-scales 
on the swollen places, about the middle of Apiil (Fig. '2'2'>. l ). 
The teleutospores are two-celled, the earlier formed ones being 
short, ovoid, ami sligiilly pointed at each end, while the 
later ones are ihiniiri-wulled and often more elongated 
(Fig. 22.'., (J- 10). 




KiG. 223.— Ttiiigeutial lougitudiiuil sec- 
tion thruugb the jjiireiicliyiutt-zoiie of 
Kig. -220. (After WoenUe.) 



'llarlig, hiHiAixfH of Tni-i, KiigliHli editioii, l.s!t4. Diilrl, l\ii^iif li naiuf- 
iiUt. ZtitH,hrij't, 189.')," p. :;»S. K. FiHclier, IJaliri.jia, 189."», p. 1. 



390 



UREDINEAE. 



In May or June the cushions swell up and become large 
brownish-yellow gelatinous clumps, dotted over with dark points, 
the teleutospores. Promycelia arise from one or more germ- 
pores in each spore, and give off basidia with sporidia (basidio- 




FiG. 224.- — Aei-idia and Pi/cnidia of various species of Gymnonporangiurii : 

G. iremelloides — 1 and ;?, aecidia on leaf of Pyrus Aria ; 5 and 6, aecidia on leaf 
of Pyrv.s MaAus ; 19 and 20, portions of the peridium of an aecidium from 5, 
showing the peculiar articulation of the cells. 

6. juniperinuM — 3 and U, aecidia on Pyrus Aucuparia ; 7 and S, aecidia on 
Amelanchier vulgaris. 

G. clavariaeforme — 9 and 10, aecidia on Pyius latifolia; 11, 12, and IG, aecidia 
on CraUttgv.if Oxyacautka, grown out-of-doors ; lU, the same aecidia, enlarged ; 
1-1, I'l, and 17, aecidia on Crataegus Oxyacanthn, indoor culture ; 18, deformed 
twig of Crataegus bearing pycnidia. (After Tubeuf.) 



spores) capable of immediate germination. The gelatinous mass 
dries up from time to time, leaving a bright yellow scar on 
the swollen part of the host-branch. The sporidia germinate 
most easily on species of Sorhns (P//ri(s). Infections with 



GYMXOSPORANGIUM. 



391 



Gymnosjyorangium jiinipcrinvm L. and G. trcmfUoides Hart, from 
twigs and needles of Juniperu.^ communis produced: 

On Host-plant. 
Pi/rus (Sorbus) Aiwupariit, 
Aro/u'a rotundifoUo, 
Pyrus Malu.i, - - - - - \ 
Pynis {Sorbus) Aria, - - - j 

Cydonia vxdgaris, - - - - 
Pyrun (Sorbus) Auatpariii, 
Pyrus Malus, - - - - - 
Amel'iiic/iier canade/isis, - 
Pyrus (Sorbus) A no, ... 

Pyrus Mahis, - - - - - 
Pyrvs (Sorbtis) Chamaemespilus, 
Mespilus macrocarpa, 
Pyrus communis, - - - . 
Pyrus (Sorbus) Aria, 
Pyrus (Sorbus) Aria x Chamaemesp., 
Pyrus Malus, - - - . - 
Pyrus (Sorbus) Chamaemespilus, 
Pyrus (Sorbus) A ucuparia, 
Aronia rotundif<jlia, 
J'yrus (Sorbus) tonninalis, 
Crataegus Pyracantha, 
Cydonia vulgaris, 
Pyrus Malus, ----- Hostel ia penicillata, - Rostrup. 



Spore-form. 




Authority. 


Rostelia cornuta. 


- 


- Tultcuf. 


sliort aecidia. 


- 


- R;ithay. 


]>_V(_nidia, 


- 


'» 


Roestelia (?), - 


- 


)> 


(?) 


- 


- Plowright. 


pvcnidia, 


- 


- Tha-xtei-. 


Rostelia cornuta. 


- 


M 


R. penicillata. 


- 


- Haitig. 


R. penicillata. 


- 


- Nawaschin. 


R. penicillata, 


- 






spots, 


- 


- Peyritscli. 


tliick spots, - 




,, 


pvcnidia and aecit 


lia. 


)' 


thick spots, - 


- 


., 


pvcnidia and aecii 


lia, 


- 


pycnidia only, 


- 




pvcnidia and aeci< 


ia, 


,, 



[tycnidia and spots oidy, 



Rostelia penicillata. 

Formation of pycnidial spennogonia always iirecedes that 
of aecidia. 

This fungus is of practical import on account of its occurrenci' 
on leaves of apple-trees. Its attacks may be very virulent 
and widely distributed. Eriksson mentions that near Stockholm 
it is common on apples, and so virulent that many trees have 
every leaf studded with Iiocstclia. (American apple-trees sud'er 
from lioe.stdia 'pirafa, the aecidia of (ii/mnosporanijiuiii maoutpua 
and other species. See )>. H)L'.) 

Gymnosporangium juniperinum (L.) (^r, raiiinnii Ibdw. > 
(Britain and I .S. .Viucrica). This species, also frtMpu'nting 
Jiinipiriis nrniiuHnis, is distinguished by its shorter spores, 
which, as Dietel pointed out,^ have a eolourless ])apilhi over 
each germ-por»'. The teleutospores are found on both twigs 
and ni'edles, on the fninirr, huwrvci', thf\' air mutli smaller 



^ Furitlirlinutliririss. /lifiifni/t, ISil.'i, p. 'A'S. 



392 



UREDIXEAE. 



than those of G. tramiloides. The aecidiospores — Boestelia 
cormcta — occur on species of Pyrus (Sorbus); they are much 
smaller than those of Boestelia pciiicillata. The Boestelia 
themselves are long, curved, and horn-like, while the walls of 
the peridial cells are beset with short processes (Fig. 224). 
Where Pi/rns AuciqMria occurs mixed with Pyrus Malus, 
it has been observed that Boestelia cornuta is confined to the 
former species exclusively. The Boestelia is the cause of a 




Pig. 225. — Gymtwsporangium juniperinum and G. trcmelloides. 1, Young spore- 
cushions breaking through the bark ; 2, the same in swollen condition ; 3, gela- 
tinoiis cushion arranged to show its lower surface ; U, Juniper-needle with three 
spore-cushions ; 5, young Juniper plant bearing cushions on its needles ; G to 10, 
spores of various kinds, to show the variation in size, shape, and thickness of 
wall ; 11, cell of a prumycelium -with a sporidium attached ; 13, germinating 
sporidium. (After Tubeuf.) 

marked deformation of leaves, petioles, and even (though rarer) 
fruits of Pyrus Aucujiaria and Aronia rotundifolia, both in 
the lowlands and mountains. 

I have produced Boestelia cornuta on Pyrus Aucujjariet by 
artificial infection with portions of spore-cushions from twigs 
of juniper, and have observed a mountain ash in closed forest, 
with abundant Boestelia, directly beneath an overhanging juniper 
with diseased needles. 



i;ymnosporangium. 



393 



Woernle investigated the anatomical changes induced by the 
various Gymnosporaiujia frequenting the twigs and needles of 
Juniperus communis. In the needles the mycelium lives inter- 
cellularly, at first outside tlie endodermis, but later also penetrating 
within this. The sporogenous cushions originate on the upper 
surface of the leaf to right and left of the middle nerve, 
where the stomata occur and hypoderm is absent. At tliese 
places a cushion or stroma of pseudoparenchyma is produced 
and ruptures the epidermis (Fig. 226). This however is at 
once healed over by a cork -formation round the margin of the 
cushion, again to be ruptured as the latter increases in size, 
once more to be healed bv cork-formation, and so on. In 





Fio. "2215. — Comparison of (<») noniiiil Juiiiper-neciUe witli one ('-) buuriii^r teloito- 
sjHjrcs of Gi/-iiHO»jioruiiiiiiim. In n the double outline indicates the hyiK>dcnu ; 
the uentr.il vaseuliir bundle and an underlying resin-canal are ^hll^vn. (After 
Woernle.) 



this way a corky layer is formed under the sporogenous cushion 
and gradually displaces it. If in a following year the cushion 
be again formed, the scar is ruptured and lieals as before. 
Needles frequently remain in jiosition for two, three, nr fnur 
years, but UKJst (jf tliem fall olf in the lirst autumn. I'mler 
the sporogenous cushion the cells «jf the mesoj)liyll inciease 
botli ill huiiiIkm' and size. 

in considering the twig-deformations, Woernle tlistinguishes 
the I'orm assumed by tiie (i'//iii/iusj)(irt(iii/iinn on the needU's, as 
just descrii)ed, from a iorm wliich iiihal)ils tlie thicker twigs. 
JJoth cause deformation of twigs, but tlieir elfeets (Ullei as I'ollows: 
"The needle-iiibabitiiig form can only eause a slight swelling 
extendiiiLj almost regulaily round the whole twig: the twig- 
inliabitiii^,' loim, on the oilier liaiid, alwa^■s i;i\es |-ise to a \eiv 



394 



UREDINEAE. 



marked swelling on one side only (Fig. 227). In the needle- 
form the swelling results from increased growth of the rind, 
with a simultaneous decrease of growth of the wood ; in the 
twig-form the growth of both wood and rind is much increased. 
With the twig-inhabiting form the medullary rays and wood- 
parenchyma increase, and at the same time become filled with 
mycelium (Fig. 228); whereas with the other form the medullary 
rays are at most only somewhat broader, and no mycelium can 
be found in the wood. The greatly swollen rind in the case 





Fig. 227. — Section of a nine-year twig 
of Juniper attacked by &'!/(/t}iospo)'aH(7iM?)t. 
The rind under the spore-cushion is 
much thickened ; the wood towards the 
same side is much broken up by tracts 
of parenchyma. (After Woernle.) 



Fig. 228. — Tangential section througii diseased 
wood beneath a spore-cushion. The wood- 
elements are much displaced by abnormal tracts 
of parenchyma. (Only one of the latter has been 
filled in, the others left blank.) (After Woernle.) 



of the twig-inhabiting form is due more to increased growth 
of the cortical cells than to increase of bast-parenchyma ; in 
the needle- form, however, the swelling is the result of increase 
of the bast, especially of the bast-parenchyma. In twigs 
infected by the needle-form, the mycelium may be found all 
round, but it has difficulty in making its way radially to the 
cambium; in the twig-form the mycelium, as early as the 
spring following infection, will be found to be in close contact 
with the cambium on the infected side, although it requires 
several years to pass round to the cambium on the opposite 
side of the twig. The mycelium and spores of the two forms 
differ little from each other." 



GYMN0SP0RANGIU5I. 



395 



The strikingly characteristic cleavage of the wood l»y the 
overgrown elements of the medullary rays and the wood- 
parenchyma, in the case of the twig-inhabiting form, will be 
seen from the figures (Fig. 229). As already noticed, the 
sporogenous cushions are generally formed on one side. After 





Klii. 2'J'.'. — Two suctions from ii swcUiuK "li ;i JniiiiiLT-brani-h. ". Kroiii tliu 
luidJle of tliu swelling' ; the rind under the Hi«jru-L'ii8liion is uiucb tliiokcned, und 
tiio wood is iniiL-li brokun ui> l>y tnii-tM of parenclijnui. t/, Section from "J cm. 
under « ; abnormal development of iiureneliynui in tlie woo*l has be^un in the 
outer ycar-ring«. (After Woernle.) 

the shedding of the cushion, a corky layer arises in the iiaii'ii- 
cliviiiii iiii<lfiiic;it li it. and so a Ijaik-scale is prodiicuil. 

Gymnosporan^um sabinae (Dicks.), (liritain.) Thi- myctl- 
iiiiii hilji'riial(;s cliictly in Jiin'q)enis Su/'im' (Savin), and iii(lu(i'> 
.sWfllings on llif Iwiu's. It also occurs on .//'//. O.i i/odnis, 

'1 fiiiiiiil llii-i lioHt sijecif.s iifui- Kiuiiif. 



396 



UREDINEAE. 



Jun. virginiana, and Jun. phocnicea. (A reported occurrence on 
Pinus halepcnsis is probably an error.) 

The sporogenous cushions are little dark-brown protuberances 
which break forth in spring from swellings, or on green 




Fig. 230. — Gymnosporanciium xabinae on twigs of Juaifii ras Suhinn, at the time 
of liberation of spores, (v. Tubeuf phot.) 



twigs and scale-leaves. These bodies absorb water, swell, and 
run together, forming transparent gelatinous masses (Figs. 230 
and 231). The teleutospores resemble those of G. juniperinum, 
but have only four germ-pores ; they germinate on the 
gelatinous masses, and produce promycelia and sporidia. The 
latter germinate at once, chiefly on leaves of Pyrus com- 
munis. The pycnidia are produced on the upper epidermis 
as sticky yellow spots bearing darker dot-like pycnidia. The 
aecidia (liocddia can cell ata) are found in September on the 
nnder-surface of the leaves of pear, also on leaf-petioles, young 
shoots, and even on the fruits. The peridia differ from both 



GYMXOSPORAX( ;i I' M. 



397 



the species already described in remaining closed at thr apex, 
the spores escaping through trellis-like slits on the lateral walls 
of the peridia (Fig. 2o4). 

This fungus will not germinate on apple-trees, but on pears 
every leaf may be thickly covered with aecidia and pycnidia, 
and considerable damage to the crop thereby ensue (Fig. 2o:'<}, 





Fic. 231. — Lougitudiiiul section through 
a conical teleuto.spore-.sonis of Gymno- 
fporanijixim Sabinat. (After Woernle.) 



Fici. 2;{2. — Telcutospores of G. snblnin: 
The elong-.itcd thin-walled ones arc 
lighter in colour than the thick-\v;illcd. 
(After Woenile.) 



Infections on varinus hosts with (r'i/iiiiiosji(irfi/i;/iinii sd/nnor 
IVdiii JunijJenis Sahina gave: 



< )u HoHt-jtlant. 
l'}jras rommuiiig, 
Crataeg^is Oxyacantlm, 
Mespilus gennnnicn, - 
I'yniii cuminiuttK, 
Pi/ruK co/iiiiii'inK, 

„ MiiliUU.rii, 

,, toinendiKii ^ 
J'l/rim ritmiintiii.'f, 
I'l/rng cuiiimiiiiix, 
('rutiifiiiiK O.rijiKii iitli'i. 



Sport'-forni. 

(0 - 

Itusttlin caaci-llata. 



-VutlioritN . 

I'lnWli-llt. 

Ocrstfilaiiil l>f Itjiiv. 
IMtliiiy, Tubiiif, etc. 

K. iMs.h.r. 
Kl.-I.aliii. 

,, (Mill citaiii). 



398 



UREDINEAE. 



The anatomical changes exhibited in diseased parts of pear- 
leaves have been briefly described by Fentzling.-^ He found a 
radial elongation of the cells of the spongy parenchyma and an 
accompanying accumulation of starch. Wakker, about the same 
time, obtained similar results in the case of Crataegus Oxya^antha 
deformed by G. davariaeforme (see p. 387). Wakker observed 
a diminished formation of calcium oxalate ; Fentzling, however, 
found increased deposit of the same salt, not only in the form of 




Fio. 233. — Gymnosporangium sahinae in the form of Roestelia canceliata on 
leaves of Pear. A few twigs showing the abundance of aecidia over the whole 
tree. (v. Tubeuf phot.) 



isolated crystals but as masses. Cork-formation was suspended 
in Wakker's case, while in Fentzling's a partial formation of 
cork was distinguishable beneath the epidermis. The increased 
thickness of diseased leaves is due principally to multiplication 
of the spongy parenchyma, the upper layers of which frequently 
become more or less palisade-like. When pycnidia (spermogonia) 
are formed on the upper leaf-surface, the palisade parenchyma 

^ Fentzling {loc. cit.) and Peglion (Rivi.sta di Patolo(jia Venetcilc, ii.), also describe 
tliese alterations. 



GYMNOSPORANGIUM. 



399 



of the spot in question is either completely destroyed or tiaus- 
formed into irregular cells, separated by intercellular spaces. 

The anatomical changes in swellings (Fig. 235) induced by 
(t. sdhinae on JunijHrus Sahina were investigated by Woernle 
with the following results. Wood, bust, and rind are increased 
round the whole circumference of the stem. Along with 
the broadening of the year-rings, however, there occurs a 
change in the structure of the diseased wood. The same 




Fir,. 234.— A few leaves enlarged from Fig. 233. Tlie leaf t« left han.l bears 
pycnidia on red ti\>otti on the upper surface of the Iciif ; the remaining Icjives boar 
aecidia on raised portions of their surface. Several aecidia still further enlarged 
show the peridia dehiscing by longitudinal slits, (v. Tul>euf del.) 

ti.ssues occur in tlie year-rings as already described fur (;. 
dacariarfonne, viz. thickened twisted tracheid.s, locsely connected 
together and with fissure-like ])its; medullary rays more 
numerous and Ijroader ; the hmits of the year-ring diflicult to 
distinguisli : and a yellow pigment deposited in the walls of 
all the element.s. A ti.ssue of thi.s nature may be found round 
the whole circumference of a twig even in ibe first year after 
infecti(jn, and regularly each succeeding year. Woernle only 
rarely found zones of irregular cell-formation like those 



400 



UREDINEAE. 



characteristic of (/. davariaeformc. Xo myceliuia occurred in 
the wood. A comparison of normal bast with that of infected 
twigs revealed changes similar to those already described for 
G. davariaeformc. In addition, it is to be noted that the 
thickened bast-fibres no longer occurred in closed masses, but 
were often completely absent in the first year after infection, 
while in all diseased twigs every intermediate stage exists 
between thin-walled bast-elements and thick-walled bast-fibres, 
such as never occur in the normal twigs ; in fact, many twigs 
had thin-walled elements only. 







Fig. 233.— Swelling from 
a branch of Janiperus 
Hahina attacked by Gijmno- 
■•ipoi-dngium nahinae. Dia- 
meter at thinnest part 1"7 
centimetre, at the thickest 
6 cm. (v. Tubeuf phot.) 




Fig. 236. —Sections of a twig of Savin attacked by G. aahlnae. 
n, At thickest part of the swelling ; b, 3 cm. under a and normal. 
In It is shown one of the hollow teleutospore-cushions ; five 
cushion-scars ; in the second-year ring are two shaded zones 
of wood, chiefly composed of ixxronchyma. (x 25.) (After 
Woernle.) 



The sporogenous cushions of G. sabinac are formed in quite 
a different manner from those of G. davariaeformc. Beneath 
each cushion the bast increases very rapidly and forms an out- 
growth, which is still further enlarged by the addition to its 
apex of six or seven rows of radially arranged cells, rounder 
and smaller than the bast-cells of the cushion. The mycelium 
penetrates between these outer cells, and forms over the whole 
cellular outgrowth a pseudoparenchyma from which the sporo- 
f'enous tissue arises. 



GYMXOSPORANOIl M. 401 

A sharph' (^letined ruiinclish scar of a light-yelluw colour 
remains after the spores are cast. This is composed of a 
superficial layer of coloured pseudoparenchyma, with an under- 
lying scar-tissue of characteristic constitution. The latter con- 
sists of several layers of cork-cells extending from one edge of 
the scar to the other, separating the cushion from the twig- 
tissues. This scar-tissue is not broken through next year, Itut 
the new sporogenous cushions break out through other parts 
nf the bark (Fig. 23G). 

6. COnfusum riowright.i (liritain.) Tliis is found on 
Jtiniperns Sahina along with G. sahiaac, from wiiicli it is 
difticult to distinguish. Tycnidia and aecidia are produced 
generally on Crataegus Oxyacantha and Cydonia vulgaris, rareh' 
on Pyrus comnumis. The aecidia on Crataegus resemble those 
(jf C elavariaeformc on the same host, and dehisce by the 
ruptured apex of the peridium. Those produceil on I'yrus 
eommunis are distinguished'- from aecidia of G. mhi/iai i»n 
the same host by dehiscing through the open apex of the 
peridium. 

Infections of ^/////'. rojifusum from Juniperus cant munis gave 
the following results : 

On Host-plant. Autliority. 

/. I ■ 7 i uvtiiidia ami at'cidia witli \ ,-, ,-,■ , 

I idoii.ia vulqanx, - - • • i i • i- A'- risrluM. 

•^ ^ I tuliular i)tMi(lia, - - | 

Crataegus Oxyacantha, - ,, ,, 

J'yrus communis, - - „ „ „ „ 

Crataegus O.rydcantlni, - ., ,, „ I'luwiii^lit. 

The following xVmerican species of (iyiuitusiKirtntgiu m have 
been described:-' 

( )n Arb(ir\itae (jr white cedar: 

G, biseptatum Ellis. On twigs and needles nf Clinniairyparis 
thyoiilis and Lilmcnl rus (Iccwiirns. i'lu- aecidia on Crattugus 
foiniiitosa ami Annhi ndui r nmadi nsis. 

' I'lnwiij,'lit, Liiiiifaii Sor. Journal (liotaiiy), ISMT. K. Fisiher, ZtlUchrij't /. 
I'jlair.inkrtinkhtitfii, I., 18!>1 ; witli Miiiiimary <»f literaturi-. Klvliuliii, Forxt/.- 
iiu/iiruiMM. Zi-ilxrhrijI, 1 1., lH!i:!. 

- K. Fisclier (lor. rli. ). 

■Fallow, 77i<- I)> nliijimHul of tli> (•i/iiniosj,i,r(i>iiiin of lln Ciii/nl Slalt.^, ISSG, 
uikI otIuT paptiM. Tlmxtor in various papers on (Jynniosporangia, lS«(i t<> 
18!H. HaJMted {Ifijtort on \'i,ji tnUf I'nlholo'iy for 1888, U.S. Ik'pl. <if Agii 
culture) gives a nxunn', with ileHcii|>tion ami lij'Uies of (/. vinirojint an<l 
titatment for in xliaul ru.st. Fistlier, X> ilH,luil't f. I'ftttn-.f idranUn i/t^ii, I., 1 S'.U . 



402 



UREDINEAE. 



G. Ellisii J]erk. On Cliamaccyparis thi/oidcs. The aecidial 
stage on Pyrus Mains and P. arhutifolia. 

On I'ed cedar (Junipcrvs virginiana) : 

G. macropus Lk. The aecidia and pycnidia occur on Pyrus 
Mains, P. coronaria, P. arhutifolia, Crataegus tomentosa, C. 
Douglasii, and Amelancliicr canadensis: they are k'nown as 




Fig. 237.— Spores of 
Gym. hiscptatum, (After 
Woernle.) 



Fio. 238.— Spores of 
Gi/m. Ellisii. (After 
Woernle.) 



Fig. 239. — Spores of 
Gym. macropus. (After 
Woernle.) 



Roestclia pirata. This is one of the commonest causes of 
apple-rust and of the deformation known as " cedar apples " (Fig. 
240). The anatomy of the latter structures has been described 
by Sanford.^ 

G. clavipes Cooke et Peck, occurs on Juniprrus commnnis. 
Its aecidia and pycnidia are found on Pyrus Mains, P. arhuti- 
folia, and AmclancJiier canadensis. 

^ Sanford, Annals of Botany, i., 1887. 



GYMNOSPORANGIUM. 



403 



G. g-lobosum Farl. Aecidia on Pi/ru.'i Mains, F. communis, 
Ci/rhnia vulgaris, Sorbus amcricana, and species of Crataegus. 

G. nidus -avis Thaxt. Aecidia and pycnidia on Fyrus Malus, 
Aiinhiitrho r iiiuadi asis, and Cydonia vulgaris. On the red cedar 
it causes the " ])ird's nest " deformation of the l>ranch-system. 

G. speciosum IV k. On Juniperus 

G. Cunninghamianum I'.arcl. On 
Ci/jircssu.s torulo.sa in the Himalaya. 
Aecidia on Fyrus Fashia. 



Tlie following genera do not occur 
ill Europe. Coleopuccinia, Eavcndia, 
Alceolaria, TricJiosporn. '^'^ ; 

Ravenelia alone amongst these / 

coiiiains jiarusitic species of import- 
ance. They all occur on Leguminosae 
and Eui)liorbiaceae in the warmer parts 
(if India, Africa, and Aiiicrica.^ 

Ravenelia Volkensii Iliim. has teleutospore-s<tri which ai)jiear 
on " witches' bioum "' deformations of the twigs of an Aim- in in 
Usambara. 

Rav. pymaea f.ager. et Diet, produces its teleutospores on 
malformed branches of Fliyllanthus in Ecuador. 

Certain forms of Accidium which cause deformation of species 
of Acacia should probably be included in this genus (see p. 410). 




FiQ. 240. — Cedar Apples caused 
liy Oijiunonporangium. macropu*. 
(v. Tubeuf del.) 



Endophyllum. 

Teleutospores originate serially on cu.shiuns which are enclosed 
in a peridium similar to aecidia ; on germination, a four-celled 
promycelium is produced.- Leaves of Euphorbia, Sedum, or 
Siiiiiiuii ni III inhiiliilcd by iiiycflium develop abnormally. 

Endophyllum euphorbiae-silvaticae (D. C) (Ihitain). Aicord- 
iiig to W'iiiiii, the ])eri(na are regularly distributed over thi; 
underside tjf the leaf of Uup/iorhin amygdaliiidrs\ they have 
white fissured margins either erect or somewhat turned back. 



' Dittel, "Tlie (;eiiiiH Kiiveiieliii," J/nlin)tia, 1SI)4. 

■' Till' tcli'iitoK|Miri-H of tluH geiiu.s iniglit be ilescribetl as ai'ci»iiuHj»orc« wliii-li 
proiliui- |)r<>iiiy<<lia. 



404 UREDINEAE. 

Spores yellow and polygonal. Leaves when attacked remain 
broad, short, and pale coloured. 

E. sempervivi (Alb. et Schw.)^ (Britain). The aecidium-like 
patches of teleutospores occur on wild and cultivated species of 
Scdurii and Eschneria. The spores produce promycelia from 
wdiicli arise sporidia which germinate on the same host-plant. 
True aecidia are unknown, but orange-red pycnidia (spernio- 
gonia) may occur. Leaves of attacked plants are pale and 
aljuormally lengthened.^ 

E. sedi (I). C). Teleutospores occur on species of Scdicm. 

The genus Pvxciniosira found in Ecuador contains few species, 
and none of them important parasites. 



Aecidium-Forms 

The relationsliips of v:]iich are uncertain. 

Aecidium elatinum Alb. et Schw. (Britain and U.S. America). 
The witches' broom of the silver fir."^ This Accielivvi is widely 
distributed in forests containing silver fir (Abies _^9fc^/n«/«), 
and produces canker of the stem frequently accompanied by 
that deformation of the branch system known as a witches' 
broom. 

In Germany it has also been observed on Abies Nordmanniana, 
A. ccplicdonica, A. Finscqjo ; in Xorth America on A. balsamca ; 
and in Siberia on A. Pichta. 

As a result of the presence of this fungus, globose or barrel- 
shaped swellings make their appearance on stems and branches 
of all ages and on all parts of the trees. A single stem may 
carry one or many of these, and they continue to increase with 
its growth. If, as is frequently the case, the bark covering 
the swelling becomes ruptured and partially detached, then 
the wood left uncovered becomes a wound, and falls an easy 

^Leveille, BuIleJ. Science. Natin:, xvi., 1825. 

- Illustrated in Kenier's Natural History of Plants, English Edition (Fig. 3o8). 

•'De Bary, Botan. Zeitunr/, 1867. Weise, "Zur Kenntniss d. Weisstannen- 
krebses," Mibulener Forstliche Hefte, 1891. Heck., ^ Der Weissfaiivenkrehs." 
Springer, Berlin, 1894 ; with Illustrations and Bibliographj'. 

The canker is common throughout Britain, Init witches' brooms have not 
been often recorded. (Edit. )1 



AECiDiiM fui;ms. 



405 



prey to wood-destroying fungi,' The presence of such rotting 
spots renders the tree liable to Itreak over in tlieir neighbour- 
hood, while they, as well as tlie swellings im ihe trunks, cause 
a c«jnsideral»]t' depreciation in the value of the tindjer. 

'J'he malformations of the branch-system known as witches' 
brooms are fre<puMitly induced by this fungus. They occur as 
a rule on the horizontal branches and form a richly branched 
bush easily distinguished, evMi at a distance, by a marked 




Fifi. •241.— Witchen' Bi-oom oj Silver Fir (winter condition). The ncoillcs, with 
-•IioreH of Aicidium diUiamn, hiiTc fallen off, but tho normal folia(fo rouiiiins. 
(V. Tiiljciif phot.) 

negative geotropy of its twigs. The brooms not unfretpiently 
start from a marked l)asal swelling. 'I'hey may be fnund of all 
sizes, on young as well as (jld trees, on any part of ilu' liranch- 
system, anil in all localities where the tir occins ( Kigs. 241 
and 242). 

Tile aecitiia of .luiifiinn i/iifiiiinu are developed only on the 
deformed needles of the witches' brooms. These needles are 
produc(,'il anew each spring, live only onr -reason ami are cast 



' I'lily/iDin-t J/nrfii/ii iuid A'/uiiniA (iili/Hj>ii> in |i.irt iiular iniiiin|mii\ tlii.n 
iiiiker iiiitl liritig iiImhiI ilecay of tlu- wood. 



406 



UREDINEAE. 



tlie same autumn ; they are small, one-pointed, and pale from 
an almost complete lack of chlorophyll. In these respects they 
are quite distinct from the larger double-pointed normal needles 
with their dark-green colour and a period of growth extending 
over several years. All the needles on a broom are as a 
rule stunted in the manner described, yet single branches 
may be found with needles quite normal ; such contain no 
mycelium, or, if so, it has found its way in too late to have 
any effect on their growth. 




Fia. ili. — U'itches' Broom oj Silver Fir (summer condition). The m:u-kerll3- 
negative geotroiJic broom has its origin in a distinct basal swelling, (v. Tuljeuf 
phot.) 

The various tissues of the witches' brooms also undergo 
considerable modification as compared with normal twigs. A 
thicker and softer l)aik is present, due to the parenchymatous 
cells of both outer rind and bast having enlarged in size and 
increased in number ; the cork layers are also abnormally in- 
creased. The same changes may be observed in the rind of the 
swellings, and to this their increased size must be chiefly ascribed. 
The wood both in twigs and swellings is much increased ; 
the year-rings however are very variable, sometimes they are 
broader than the normal, again they may be diminished or 
even altogether wanting; where however the' wood decreases, 
there the bast increases in proportion. This lack of uniformity 



AKCIDILM-FOILMS. 



4o: 



ill the growth of the wood disturhs the elements, so that 
they are irregularly developed and more or less twisted.^ 

A mycelium inhabits the tissues of abnormal twigs ami 
cankered swellings. It grows in the intercellular spaces of 
the rind, between the bast cells and outer parts of the wood, 
and derives nutriment by means of haustoria : these either bore 
through tiie cell-walls, or only press closely against them so 
as to cause depressions. 

.Spore-formation takes place on the needles of the witches' 
brooms. The pycnidia (spermogunia) are produced on the 
upper side beneath the cuticle 
and emerge through it as little 
yellow points. The coiiidia (sper- 
matia) are tiny globose colourless 
bodies. The aecidia come later 
during June and July in irregular 
rows on the under side of the 
leaf. Tlieir peridia break out as 
low dome-like structures, the 
apices of which rupture irregu- 
larly to allow escape of aecidio- 
spores. In spite of numerous 
infections, I)e Dary was unable 
to observe the penetration of a 
germ -tube into needles or twigs 
of silver tir. Weise believes that 
infection of the fir takes place 
on twigs which have just emerged 
from the bud. 

As a preventive measure, all 
witches' brooms should Ije cut olf 
before spore-formation begins, and 

stemswith canker-wounds should be remo\id diiriii^ forest-thinninu. 
I'ny furtlii-r di-tails ibe moiKiLriaph of Heck may be consulted. 

Aecidium strobilinum (Alb. i-i Schw.)- (I5ritain). Spruce- 




I 1... J4.;. J....i.,.„c ..(,...'.,(,„,., I 

roni. (V. TulHJuf phot.) 



' .\oti-. Fill till I tliiiiil.-, ot tlie aii;iti)iiiiciil rluiii;,'cs imliKril in tin- tis.siii-s of 
tliewf witdifn' ht'doiii.s iiiay )»»• olitaiiit-il in tlir <;frin;in i-ilitiiiii of tlii« work 
(j)|>. 4'J0-4'J1), i)f ill tlu' original tlii-.si.s hy liartiiiaiin, (Aiidfoiii. I'mj/i irhiiii'i li. 
Ilfxnihfxeji 'Irr Wiixitaiiiit. Iiiiiu>(iiial DiHHtTtatioii, 1S9-. ) (K<lit. ) 

- Rc«'HH, Ilox/jii/Jonneii d. Coni/i n ii., ISOO. ()»i.slf(h, Xnfur/i. for l'itUii>l:. 
M<d,l., isra, I. 



408 



UREDINEAE. 



cone rust. This disease is found on the cones of spruce. 
The aecidia are brown somewhat flattened spheres, and appear 
in large numbers on cones distinguished by their scales stan ding- 
stiffly open even in damp weather (Fig. 243). The germ- 
tubes of the fungus find entrance in spring into the flowers 
or young spruce-cones, and the mycelium lives parasitic in 
the green scales without causing any marked change in 
their growth, although the ovules are more or less injured. 
Xo mycelium has ever been found in tlie lower cone-axis, nor 
in the shoots, so that the disease must l)e the result of in- 
fection by spores only. 




j}ar 



•?, 



Fig. 244. — Aicidium Mrohiliiiura. 1, Cone-scale of Spruce with aecidia, those to 
left dehiscing their j-ellow spores, those to right still closed, (v. Tubeiif del.) 
•1, Section through an immature aecidium. 3, Part of 2 enlarged — pti-, peridium ; 
xp, spores; tw, intermediate cells; xplr, sporophores ; m, nij'celium ; jiai-, the 
scale-parenchyma. (After Reess.) 



The aecidia break out on the inner (rarely the outer) side 
of the bases of the cone-scales ; each is enclosed in a firm 
brown lignified peridium, which ruptures by a cross-fissure 
and becomes an open disc. The young spores are joined by 
small intermediate cells, which are gradually absorbed to 
form a layer of gelatinous lamellae on the spore-coats 
(Fig. 244). 

Teleutospores of this Aecidium are unknown. 



AKriDir.M-FdIIMS. 409 

Aecidium pseudocolumnare Kulni.' Occurs <jii neetlles of 
Ahii.'i patiniitii. ill ( ;L-iiiiiiiiy : in Britain, liowever, on this and 
several other species of Ahies. It is distinj^uished by its large 
wliitt' spore? from tho A'l: iuijinnnair of C'alt/ptospom (p. .■^>72). 

Aec. Magelhaenicum lierk. This species occurs on various 
species of barljcrry. Tlie mycelium hibernates in the shoot- 
buds and causes them to develop as witches' brooms, liearinjj; 
on tlie lower surface of their leaves aecidia with \o\v^, white, 
sac-like peridia. The allied teleutospore-fnrm is as yet unknown. 

Aec. clematidis D. C. (Britain ami U.S. America). Uu Vfemads Vitulbn, 
('. i-'-'tit, and otlier species. It is related to Puccinia aj/ropyri Ell. et Ev.- 

Aec. Englerianum Henn. et Lind.-* produces a i)eculiar antler-like 
1 (ranching of the twigs and leaves of a Clematis at Eritrea (Lytri) in the 
(heciau Archipelago. 

Aec. punctatum Pers. {Aec. quadrifidcui B.C.) (Britain and U.S. America). 
This is a common species on Anemone (Fig. 190) and Eraiithis. The 
aeiidia have white peiidia, which on dehiscence break into four lobes. 

Aec. leucospermum D. C. (Britain and U.S. America). On Anemone 
nemorosa (Fig. 190). 

Aec. hepaticae Beck. On Anemone Hepatiea. 

Aec. ranunculacearum I ». C. (Britain and U.S. America). On sj)f<it-s 
of Itniuiniidus. A collective name for aecitlia of several s])ecies of I'romyies 
(\K :i3n), and rucrinia (p. 349). 

Aec. aquilegiae Pers. (Britain and U.S. America). On Aijin'/rifio 
riilijiiris and other specie.s. (See 1'nceuiin offrostiili.i, p. 349.) 

Aec actaeae (Opiz.). On leaves of Actiiea spieata in Eniope and America. 

Aec. barbareae !).('. On species of Ilarharea (Biitain). (See /'"<<•. 
fstiir,,,-, |,. :ii;».) 

Aec. circaeae < Vs. On species of Circ'co. 

Aec. grossulariae Schum. (Britain and T.S. America). On /lilxx d'roiMU- 
luria and /{. nihrirm. Kleliahn 1)elie\es it is related to a l\«<'lniit on Cure.r. 

Aec. bunii I>. C. On ('oiiitfiijilinia <l>'itii.<liitiiin in Ihitain. (.'"^ee I'hk-. 
histnrt.i,-, p. :^.-,.-,.) 

Aec. periclymeni Srhuni. < >n species uf Luineeru. (Britain.) (See I'ni-i'. 
t',.<t,i,,i<. p. ;', i;t. ) 

Aec. compositarum. A provisional spccies-nanie for a large niimlier <•(' 
aecidia fni|iienliiig ( 'ompositae, and liv no means resembling each other. 

Aec. leucanthemi 1 >. ('. A European species with its I'lU'riniaUnxw on 
(.'iii'i-.r iiinntii nil. 

Aec. cyani !).('. On Cvntunren Cijunnx. 

Aec. ligustri .'<tiaiis<. ( »ii I'rivet. 

' Jf'iliri'jifl, 1.SS4. 

- Dietel, OfMfn-iMrh l,„ftiii. X'i'iiini, lS!t-J. 

' Kiigiers ISulnii. .luhrlm.h, ls<t:«. 



410 UREDINEAE. 

Aec. phillyreae D. C. On species of Phillyrea (Britain ?). 

Aec. fraxini Schweiii. This causes serious damage in America to the 
foliage of Fra.vimts viridi)^ and Fr. americana.^ It has also appeared in 
Europe on the latter species introduced from America. 

Aec. nymphaeoidis D. ('. On leaves of Limna/itheiman, Niq^har, and 
Nymphaea. (Britain.) 

Aec. pedicularis Lili. On Fedicul<<ris. (P3ritain.) (See Pvcc. prdudosa, 
p. 3ol.) 

Aec. prunellae Wint. On PruneJla vidgarix. (Britain.) 

Aec. euphorbiae Gmel. is found on many species of Euphorhia. It is 
proliably the Aecidium-iovm of Uromyces pisi. (Britain and U.S. America.) 

Aec. convallariae Schum. (Britain and U.S. America). Probably a 
provisional species-name for aecidial forms found on CovraUaria, Polygon- 
atum, Paris, Lilium, etc. (See under Puccinia.) 

Aec. ari Desm. {Aec. dracontii Schwein.) is found on species of Arum. 
(Britain and U.S. America.) (See Puce, phalaridis, p. 349.) 

The following species are found on Acacia and seem to have 
strong affinity with the genus Ravcnalia : 

Aec. esculentum Barcl. produces deformation of twigs of xicacia ehurnea 
in India. Twigs of this kind, likewise shoots deformed by Aec. urticae var. 
himalayense Barcl., and pine-shoots deformed by certain species of Perider- 
minm, are eaten in various parts of the world. 

Aec. acaciae (Henn.) on Aicacia ethaica in Abyssinia. This is said by 
Magnus to cause witches' broom deformation. 

Aec. Schweinfurthii Henn. causes malformation of fruits of Acacia 
Fistula in Africa. 

Aec. ornamentale Kalch. causes curvature of shoots of Acacia Iiorrida 
at the Cape. 

The following are some of the more important species 
recorded for Xorth America only : 

Aecidium dicentrae Trel. Leaves of Dicentra and Corydalis. 

Aec. monoicum Peck. Leaves of Arabis. 

Aec. drabae Tr. et Gall. 

Aec. lepidii Tr. et Gall. 

Aec. proserpinacae B. et C. 

Aec. Mariae-Wilsoni Peck. 1 ^ . r t-- ; 

-On species or I lola. 
Aec. Petersii B. et C. ) 

Aec. cerastii Wint. 

Aec. pteleae B. et C. On leaves of PteJea trifoliala. 

Aec. xanthoxyli Peck. 

Aec. splendens Wint. In the cotyledons of Croton mouantliogyini.s. 

Aec. aesculi Ell. et Kell. 

Aec. psoraleae Peck, and Aec. onobrychidis Burr. On species of Psoralca. 

^ Pound, American Naturalist, 1S88. 



AECIDIUM-FORMS. 411 

Aec. Peckii I)f Tmn aiul Aec. oenotherae Moiit. (Jii leaves of species 
of Oenotliern. 

Aec. sambuci Schwein. On leaves ami stems of Sumhveus. 

Aec. ceanothi Ell. et Kell. 

Aec. abundans Peck. On species of By inphoricur^jn^. 

Aec. cephalanthi Seyiu. On Cephalantlms occidentale. 

Aec. erigeronatum Schwein, On many species of Erigeron. 

Aec. asterum .Schwein. On species of Aster and SoUdugo. 

Aec. polemonii Peck. On Polemonium and P/tlo.r. 

Aec. apocyni .Schwein. On leaves of Apoct/nt'iii. 

Aec. Jamesianum Peck, and Aec. Brandegei Peck. On leaves of si>ecies 
of Ascl''pi'.i-<. 

Aec. myosotidis Biur. On leaves of Mi/osotii< cenui, etc. 

Aec. plantaginis Ces. On leaves of .species of PlunhKjo in Europe and 
Amcrii-a. 

Aec. pentastemonis Sihwein. On s))eeies of I'entstemon. 

Aec. giliae Peck. 

Aec. lycopi ( lerard. On leaves and stems of L>icopii-^ europoenx. 

Aec. iridis (Jciaicj. 

Aec. macrosporum Peck, and Aec. smilacis Schwein. On species of 
Smila.i . 

Peridermium 

Peridermium pini (Wilkl.)^ is found ou piiie-tivcs in Europe, 
liritain, and L iiited States. A teleutospore-stage of this has not 
as yet been identified, althouuh a very similar species (Frri- 
(lermium Cornni Iiostr. et KU h.), also oceurrintj; on the l)ark of 
pines, has been proved to have as its teleutospore-furni Cruiinrludn 
(iHclfpiailrtirn.- 

The niyceliuui of Prr'nhrmiinn pini lives intercellularly in 
the rind, bast, and wood of Finns st/l rest vis, P. Laricin, J'. 
ludcpiasis, P. maritime, and P. niontana. It lives and extend.s 
thr(nigh the stem for years, atlackino the li\inu cells and 
absorltint,' nutriment from them by little haustoria. The cells 
of parencliymatous tissues are those most j^'enerally attacked, 
and till* mycelium lias been I'tuuid to penetrate alon,:,' the 
me(lullary rays to a depth of I U cm. into the wood-ma.ss. 
The cells of attacked parts lose their normal content inchulinii 
starch, ami secrete crude turjienline in siuh (piaiitily as to 
completely jiermeate their walls, and e\en to form drops. In 
this way portions of the wooil bt'come completely saturated 

' R. Hartig, H'ii/i/i,/, Kninkli' it> n il. WttlillMhtuuin. 

- KUbaliii. Ii> ,',<hi, if. il.Hlsih. hotdii. <!,srll->,hnO, 1S<.X». 



412 



UREDINEAE. 



with resin, and as tlie same process goes on in bast and rind, 
the turpentine overflows from fissures or wounds in the bark. 
During the summer the mycelium grows amongst the dividing 
cambium-cells and kills them. Whero tliis occurs the year- 





FiG. 246. — Pendcrmiufii pini {corticola). 
Young twig bearing numerous aecidia. 
(V. Tubeuf phot.) 



Fig. '245. — Piridcnniurii pini (corlicola). 
Branch and lateral twigs distinctly 
swollen where attacked. They also bear 
aecidia. (v. Tubeuf phot.) 



ring ceases to thicken, but a.s the mycelium seldom succeeds 
during the first year in killing the cambium all round a 



I'EniDEKMllM. 



-tia 



branch, the living portions of the ring grow du \sitli inerea.sed 
vigour, and even attempt to close o\er the injured portion. 
This irregular growth, continued in many cases tor years, i»ro- 
duces abnormal cross-sections (Fig. 248). The mycelium 
grows out centrifugally from diseased spots, so that the wnunds 
continue to enlarge, and the disease becomes easily noticeable 
on account of the deep channels and distcjrted swellings on 
the pine branches and stems. As the disease spreads inwards 
into the stems, the conduction of water is interfered with and 
the Ijranches above such wounds dry up and die ofl'. Whereas 




iiiiiiiaii 









Fi<i. -iVi . — Pi.,-idi:vnumi\. pini (corlicola). <i, n. Mycelial stroma developed in tlic 
rind ; the host-cells have become isolated from each other and contain 
haustoria, A, of the fungus. /<, Hasidia composed of muc-h smaller cells tlian in 
tlie ncedlc-inhabiting aecidia. />, The iKjridium. (After R. Hartig.) 

young plants soon succumb to attack, the struggle with old 
trees may go on for years. Fresh infection of older stems 
occurs generally in the hiudier ])arts of the tree, where tiie 
b;irk is still thill. 

Tycnidia (six-rmogonia) are developed between the riiid- 
parenchyma (periderm) and cork, generally towanls the margin 
of diseased spots. The coiiidia emerge from llie iii|itiired 
cork-layers of the bark as a honey-sweet liipiid. II. >rayi 
states that this liniiid is gi\-en off in such tpiaiitity from 
species of ]') ridi'rnii II III in .lapaii, that it is collected and 
eaten bs' the natives. 



4U 



UREDINEAE. 



The aecidia appear in June as wrinkled yellow sacs 
emerging from the bark of swellings. They continue to develop 
in succession for years on the living parts of attacked 
branches, but according to Hartig they cease to make their 
appearance on old stems, even when a mycelium is present. 
This disease is the cause of great damage to pines, especially 
where planted as pure forest. One case is recorded ^ of a 
forest near Kohlfurt where 90 per cent, of the trees in an 
old plantation were " stag-headed " on account of a deficient 




Fig. 248. — Pfridermium 'piiii. Section through a diseased stem of Pine showing the 
gradual killing of the cambium by the fungiis. (v. Tubeuf phot.) 



supply of water in the crown accompanying attacks of this 
fungus. Until more is known of its life-history, preventive 
measures cannot be well extended beyond cutting down 
infected trees. 

The following species of Pendermium have been observed 
on species of Pinus: 

A. On the needles: 

Peridermium oblongisporium Fuck, (now Coleospormm senecionis) on 
Finns Sj/Icestris and J\ <iu,stri(ira (p. 374). 

P. Klebahni, P. Soraueri, P. Stahlii, P. Plowrightii, and P. Fischeri. 
On Pinus sylvestris ; related to various species of Coleospurium. 

P. piriforme Peck. On Pinus speciosa in U.S. America. 

P. cerebrum Peck. On Pinus rigida in North America. 

^ Marker at .Sclilesien. Forstverein, 189.3. 



I'KKIDEUMirM. 



415 



P. filamentosum IVck. On I'iiuis poiiderosa, also in America. 

P. Harknessii Moore. On PinHs ponderom, P. iii.Aig,>i.<, P. Sabineana, 

and /'. .■n„/orf'' in ( "alifoinia. 




Kii.. •2411. — PtWrf^nni urn giganUum on riau.< TftUitb-ip,: from .laiiaii. (v. Tulwuf 
jihot.— the specitneu presenteil l.y Pruf. (IraKiiuiiiu of Tokio.) 

P. brevius Baivl. (Jn Pinus excelsa in India. 

P. complanatum I lard. On Pimis longifolia in Imlia; on rind a.s well 
as needle.s. 

/A < )n tlie viiiil or bark : 

PeridermiumCornui IJostr. 
et Kiel), (now ('roil artin 1)1 
asclvpiaileHiii, \). 3M1). On 
Pi nut siflvextris. 

P. strobi Kiel), (now C/v 
iiurtiiitn ribi'iilii, p. WX'l). < )n 
Pin iisSfi-iihii.t, /'. L'lmlierti'iii'i, 
(and /'. (''-iiihi-.i). 

P. pini(VVilld.i. On /'</««.< 
xi//itih-i'x. (Britain and U.S. 
Aineriea.) 

P. orientale < ooke. On 
J'ii'iiM lii/iil'i and /'. I'irfjiiii- 
iiiiii ill Ainerira ; al.so /'. 
Longifolia in India. 




I-'|ii. 'i'tO.— P, riiltrmium ijiiiant€um nil I'inut dtntlfiora 
from Jiiiuii. (V. Tubouf phut.) 



416 



UREDINEAE. 



P. Ravenelii Tliiuu. On Finns (V'stroh's m North America (probably 
a variety of /'. ohloagisporium). 

P. deformans Mayr. On Pinns mitix in America. 

P. giganteum (Mayr). On IHnus densifloru &\u\ P. T/tunberr/ii iu Japan. 
Tliis causes ver\' conspicuous deformation of its host (Figs. 249 and 250). 

P. complanatum PJarcl. On Finns long i folia in India. 

The following species fre(|iieiit other hosts : 
Peridermium conorum Thiini.^ This aeciclium first found by 
I)e Jiary in Thuriugia, has recently been reported in Denmark, 

liussia, and America ; also in 
Upper Bavaria by v. Tubeuf 
in September, 1895. It takes 
the form of two large aecidia, 
which make their appearance 
on the outer or inner side of 
the cone-scales of spruce. The 
white peridia break through 
the epidermal tissues which 
then remain as a brownish 
sheath around each ruptured 
peridium (Fig. 251). The 
spores are separated by inter- 
mediate cells, and their outer 
coats are studded with poly- 
gonal warts. The cone-scales 
bearing aecidia contain a very 
large quantity of starch. Tel- 
eutospores of the species are 
unknown. 

Peridermmm coruscans 
Fries.- The mycelium of this 
fungus seems to perennate in 
twigs and buds of spruce. Twigs unfold from the bud as 
deformed, shortened, cone-like shoots bearing very short broad 
needles of a pale colour. The aecidia are produced on the 
deformed needles as broad lineal cushions with white peridia. 
They originate under the epidermis which they rupture, and 
break out on one side of the needle. 

^Reess, Rostpihformtn, 1869. 

^Rostrup, Vicleud: Gehl: ForlmmlL, 1884. 




^er 



Fig. 251. — Accidium conorum-picetie. per, Peri- 
dium ; sp, spore ; :w, intermediate cells ; spt,\ 
sporophore ; m, naycelluni ; pros, iirosenchyma. 
(After Reess.) 



I'EKIDKllMIl-.M. 



417 



The soi't hypertrophied shoots are eaten. Tliey occur chiefly 
in Scandinavia, l)ut recently were observed by Gobi and Tranzschel 
in the nei<ihbourhood of St. Petersbur"^ 




Fi<i. 2^)2. — A'ddium coriucaiu on malformed shoots of Spnicu. Tho compict 
abiioriiijil shoots thickly covered with white aecidia contr.iat strongly with the 
normal portions, (v. Tul>eiif j.hot. from material presented by Prof. Krie.s, 
L'psala.) 



P. Engelmanni 'lliiim. On coiie.s of /'iren Smitldana. {V.>>. 
Aiiiciira.) 

P. piceae l!:iiv|. < »ii m-cdlL-.s of I'icu Xinitliiniiit. 

P. Peckii 'riiuiii. ( >ii needles of Tnuga canadeims (IT.8. Aiiu-i iia). 

P. balsameum IVrk. On needles of AhiiK hahnmea (T.S. Anieiiiu). 

P. ephedrae Cook.-. On E^ihidni in I'.S. America. 

P. cedri lianl. On niedlcs of ValruK Deoilaiut in Imlia. 

P. Balansae ( mn. ( >m leaves of IhtiniiKira oratn in New ( 'aledonia. 

'Also lepoileil at HuHlenicre (Britiiiii), <li-n-illia, m\., IMXt. 
2 I) 



418 



UREDINEAE. 



Caeoma. 
Caeoma abietis-pectinatae Eeess.^ The aecidiospores may 
be fouiid on the lower surface of young 
needles of silver fir ; the aecidia are yellow 
elongated cushions situated on either side 
of the needle mid-rib, and are without 
peridia. Pycnidia (spermogonia) are pro- 
duced before the aecidia. The mycelium is 
septate and intercellular with few haustoria. 
I have found the fungus fairly abundant 
on the Alps and in the Danube valley near 
Passau. Teleutospores are unknown. 

Caeoma deformans (Berk, et Br.) Tubeuf 
{Uromyces deformans Berk, et Br.^ or Caeoma Asanuro Shirai).^ 
This induces the formation of " witches' brooms " or of antler-like 



Fig. -IbZ.—Carona ubiHU 
j>ectinatae. Needle of Silver 
Fir showing CaeoHia-patches 
on the lower surface, (v. 
Tubeuf del.) 




Fig. 254. — Caeoma dtjonaans on Thuiopsia dolabrala. (v. Tubeuf phot, from dried 
material presented by Prof. Grasmann of Tokio.) 

1 Reess, Rostpilzformen, 1869. 

-Berkeley, "The fungi collected during the expedition of H.M.S. 'Chal- 
lenger.'" Jour, of Linnean Soc, xvi., 1876. 
•' Shirai, Botanical Magazine, Tokio, 1889. 




CAEOMA. 419 

leariess shoots on Tliajupsi'i dolahrata in Japan, whence they were 
sent to me (Figs. 254 and 255). One example (not figured) was 
as large as a young child's head. 

The shoots of the witches' brooms are furnislied with vaseidar 
bundles and possess a parenchyma rich in starch-content. 
Each branch of the deformed shoot termi- 
nates in a hemispherical saucer-shaped 
cft^oma-cushion, at first covered over by 
the epidermis, but with no peridium. The 
cacoma-Ciiic?, are at first brown, but after 
the epidermis bursts and rolls back, the 
yellow dusty spores appear. The spores F'«- •y->b.-C(uo..,a de/o,-- 

•' _ . mans. Portion of the pre- 

arise serially from very short basidia ; they coding tigure enlarged to 

•' •' ' ./ show the Cacomo-disfson the 

are yellow and have striped membranes. ends of twigs, (v. xubeuf 

•^ ^ del.) 

The witches' brooms also exhibit marked 
hypertrophy (Fig. 254). In the supporting branch both wood 
and bark are considerably increased. Large medullary rays occur 
in the wood, and nests of thin-walled parenchyma are interpolated 
between the regular tracts of tracheae, so tliat the general 
arrangement resembles that shown in juniper by Wiirnle's 
researches on Gi/mnosporanfjii/m. The parencliymatous groups 
of cells in the wood appear to the naked eye as brown spots. 
They are permeated by a vigorous intercellular mycelium, which 
sends off large haustoria into tlie adjacent cells. 

Caeoma laricis (Westeiid).' On needles of Lari.i: (liritaiii.) 

C. orchidis A. et S. On orchiils. (Britain.) 

C. chelidonii Magn. On Chelklonium majm (U.S. America). 

C. fumariae (A. On Conjdalis. 

C. euonymi (Gmel.). On Euonymus europaeus (Britain). 

C. confluens (Pens.). On Rlbfn fdpiinim, R. rubritm, etc. 

C. nitens (0. himinaturn) is the well-known Blackberry-rust so common 
in tlif I'niti-d States. It is probably a form of Pnci'ini(i Pechoina.- 

C. aegopodii (Rebent.). On Acffopodium Podagraria and C/iacrop/ii/lliim 
'iroiiKitirviii. 

C. ligustri (Kabli.). On Litiimtnna rultjurc. 

C. ari-italici (Duby). On Arum maadatum. 

C. alliorum Mnk. (Jn Alliuin urxinum, A. olenn'i'tun, etc.'' 

C. saxifragae ."-itr.uisH. On Sii.rifrfiffn (jraituhitu}^ 

C. inerciirialis Mmi). Hn .\f,rriiriiiliH p<'iyitid:<? 

' riii.M ami ino.st of liit; other species are only sti;,'os of Home .)fifainf>Horfi. 
-Clinton, linlaniial (in-ilh, IS'.I."), p. IKi. 
'IliCMc tlnee HpecicH lire given as Hiitisli in l'ln\viii,'lit's ' Ui' liitrci' .' (Kdit.) 



420 UREDINEAE. 

Uredo-Forms of uncertain relationship. 

Uredo agrimoniae (I). ('.). <)ii species of Ayrimouid (Britain and U.S. 
America). Dietel regards it as related to Melampsora {Thecospora) agri- 
ononiiie. 

U. Muelleri Schroet. On Ridmn fruticosus (Britain). 

U. symphyti D. C On Symphytum offidiiale (Britain). 

U. phillyreae Cooke. On Fhillyrea media (Britain). 

U. macrosora De Toni. On Epilohium tetragonuvi (U.S. America). 

U. vitis Tluini. This species first attracted notice as a disease- 
producing fungus in Jamaica in 1879, but it had been found previously 
in the United States. It causes spots on the upjier surface of leaves.^ 

U. fici Cact. On Ficus Carica in Italy and U.S. America. 

U. quercus (Brond.). On species of ^^«e/-ci<s (Britain and U.S. America). 

U. iridis. On many .species of Iris (Britain). 

U. glumarum Eob. On Zea Mais in Belgium and England. 

U. sorghi Fuck. On Sorghum halepense in Greece ; (compare with 
Urorrtyces and Puccinia on the same host.) 

U. gossypii Lagei.- This has been observed in South America causing 
a rust on cotton-plants and injuring the yield of cotton. It appears as 
small purple-brown spots ; the spores are oval and yellow. 

Uredinopsis.' 

[This is a new genus found by Magnus to contain several 
Uredineae parasitic on Ferns.* The aecidial stage is unknown. 
The uredospores are abjointed singly from the end§ of sporo- 
genous hyphae ; they are unicellular and without germ-pores. 
The uredospore-sori are enclosed in a pseudoperidium of elon- 
gated tubular cells. Unicellular teleutospores (?) are given 
off from sori similarly to the uredospores. Pluricellular teleuto- 
spores are developed from the mycelium in the intercellular spaces 
of the host-plant, never from crust-like sori. On germination 
four-celled promycelia with spherical sporidia are produced. 

Uredinopsis filicina (Niessl.) Magn. On lower surface of fronds of 
Phegopteris {Polypodium) vulgaris, causing death. 

Ur. struthiopteridis Stoermer. On sterile fronds of StnUliiopteris 
germanica. 

Ur. pteridis Diet, et Holw. On Pteris aquiliiia.] (Edit.) 

^ Massee (Grevil'ea xxi., p. 119) states this species to be identical with U. 
Vialae of Lagerheim (Revue gen. de Botanique, 1890). 

- Lagerheim, Journal of Mycology, vii. p. 48. 

■'•Dietel, " Uredo jmijipodvi (Pers. )" Oesterreich. hotan. Zeitschrift, 1894; also 
" Der Gattuug Uredinop>iis," Ber. d. deutsch. botan. Ges., 1895, p. 326. 

■'These host-plants do not come strictly within the scope of this work, hut 
a short note on the genus is necessary. (Edit.) 



IIA.SIDIU.MYCETES. 421 



BASIDio.MVCETES. 



The sporophores, kiiDWu as liasidia, are structures with a 
definite shape, and with lateral branches, the steriu;mata, Iruni 
which a definite number of exospores — basidiospores — are ab- 
jointed, the basidia then becoming functionless. Basidia and 
basidiospores are characteristic of all Basidiomycetes, c<jnitHa 
and chlamydospores being produced only exceptionally. 

Tiie basidia generally arise from an extendril layer — the 
hymenium — which in the higher genera forms part of a con- 
spicuous complex sporophore. The basidia do not therefore 
originate from the germination of a spore, as do tlie promycelia 
of the Uredineae and Ustilagineae, but from special sporophores 
(rarely from the mycelium itself), whose surface they occupy, 
or in which they are enclosed. 

In the course of development, two nuclei have been found 
to copulate in the basidial cells. Thereafter they divide and 
produce four (rarely two) new nuclei (Autobasidiomycetes), or 
after the division of nuclei, cross-septa are formed, thus making 
the basidia pluricellular (Protobasidiomycetes). In Ijoth cases 
the nucleus passes through the sterigniata into tlie developing 
biisidiospores, and on the germination of these spores, it divides 
into two nufclei, the starting points for further nuclear division. 

As just indicated two divisions of the group may l»e dis- 
tinguished: (1) I'rotobiisidiomycetes, (2) Autoljasidioiiiycetes. 

Pll()TOH.\SII)l()MYCKTES. 

Cnder tliis class arc included the Aurinihirirar, FiUicirac, and 
Tremellinai', the first two possessing basidia divided, as a rule, 
by cross-septa into four cells, tlu' last with basidia also dividi'd 
intfi f(jur Cells, which are formed, however, Ijy two lon^'itudinal 
walls set at right angles to each other. A steiigma grows out 
fidm each cell and produces a single spore, after which the 
basidium dies away. The l»asidia of the Pi/iic/mf are piothued 
inside closed sporocarps (aiigioearpous), those of the otiiei- two 
groujis are exposed (gymnocarpous). Parasites are \inkii"wu 
amongst the l*rotobasidir)mycetes. 

Al loHASIDIOMVrKTKS. 

liasidia unieelbdar (autobasidia), the steri.Ljmala Iniined mi 
the a|ie\ (if lh<' basi(Hiiiii, ami eaeh uMvim; oil' a single basiiUti- 



422 BASIDIOMYCETES. 

spore. The basidia originate from basidial layers or from complex 
hymenia, produced either inside some special structure, or on 
the surface of special sporophores, or on some definite part 
of these. 

The group may be sub-divided into the Dacryomycetcs, Hymcno- 
mycetes, and Gasteromycetes (including Phalloideae). Of these only 
the nymenomycetcs contain species parasitic on plants, the others 
include harmless saprophytes, which live in the soil, some of 
them, however, taking part in the formation of mycorhiza. 

THE HYMENOMYC!ETES. 

The unicellular basidia give oft' from their apices four (any 
numl^er from 2 to 6 may occur) sterigmata, from each of 
which a single basidiospore is abjointed. The basidia arise 
from free exposed hymenia, which generally occupy the whole 
or part of large compound sporophores. The greatest develop- 
ment of the sporophore is attained in the umbrellas of the- 
Agaricincae, and the large discs of the Folyporeae. It is only 
amongst the lowest genera, like Exobasiclium, that the basidial 
layers are produced directly on the organs of the host, and the 
basidia arise directly from the hyphae. 

Reproductive cells, other than basidiospores, are rare. In a 
few cases amongst the Polypore-ae, Brefeld and others have 
observed conidia and chlamydospores (Oidia, etc.) ; while some 
few Agaricineae have the latter form of spore, but never conidia. 

The mycelium is of a very varied nature. It frequently 
inhabits wood, and in many different ways brings about 
destruction of lignified tissues. Other modifications are seen 
in the forms of mycelium known as rhizomorphs, rhizoctonia, 
mycorhiza, and other closely felted masses of various sliapes, 
which will be considered in detail as occasion requires. The 
formation of clamp-connections is also a special feature of the 
mycelium of the Hymenomycetes. In many cases the mycelium 
retains its vitality and perennates for several years. 

The genus Exohasidhcm consists of parasites which produce 
malformation of their host ; many of the Polyporeac and 
Agaricincae are deadly enemies of forest and fruit-garden, 
while as wound-parasites many of them are specially dangerous. 
The general means of combating tlieni consist in cutting out 



IIVMENUMYC'ETES. 423 

any sporophores and applying tar to the wound, while diseased 
stems in the forest should be felled. Immediate artiticial 
closure of wounds in the wood is a very effective preventive 
measure.^ 

The Hymeuomycetes are divided into Toinnitclleac, Exohasi- 
diaccac, Hypochnaccae (included hy Ihcidd in the Tomentelleaf), 
Tlidi'phorcac, Clavarira.i', Hydncai:, I'vlyporcae, and Afjaricineac. 
All contain parasitic species. 

EXOBASIDIACEAE. 

Exobasidium. 

The basidia are formed on the extremities of branches of 
the mycelium, which break out through the cuticle of attacked 
organs. The mycelium lives inside the host-plant, and induces 
considerable malformation. The basidia emerge on the surface 
of the host (similarly to the asci of the E-coasvi), and from 
each of the four sterigmata a single spore is given off. 

Exobasidium vaccinii Wor.'- (Britain and U.S. America). 
This is the cause of a ver\' common and conspicuous deformation 
which affects the leaves, flowers, and shoots of Vaccinium J^'itis- 
Lla.ea (Fig. 256). Leaves, where attected, become thickened 
and form irregular blisters vaulted towards the lower surface 
of the leaf, so that the lower epidermis covers the convex 
side and the upper epidermis lines the concavity. Chlorophyll 
is absent in the swollen tissues, but where blisters are exposed 
to direct light a bright red cell-sap is developed. Parts of 
the leaf adjoining diseased spots may remain normal and 
green. Flowers or their parts undergo similar malformation : 
twigs become more or less thickened and twisted, their chloin- 
phyll disappears, and a reddish cell-sap is ])ro(bi(i'il. ( )n sucli 
diseased places spoies are produced during the suinmcr, afUM- 
which the ])oorly developed tissues dry up and wither. 

W'lirii this fungus is jiresent in tlie young ti-ssues of its 
hosts, ii t'xerts a very marked inllueuce on their develojunent. 
The palisade cells of the leaf lieeome eidarged, while tlieir 
cldoro|)hyll almost wliojiy (Usajipears, and is re|ilariMl \\\ a red 

'Further detuilH on tluH i»(»iiit have iilroady hoeii j;i\eii, (Jiiiunil jiart, j>. 7-. 
- Wnronin, I'lr/tani/. </. nniiirjor. '.'»•■*., Froilmr^j, !S(57 : with '.\ pliitr.s, 
IJrefehl, Sr/ui,iiii>//>ll:< , Mil., Issji. W.ikkcr, PriuifM/uhn's ,/it/irl>u<h, IMhi. 



424 



BASIDIOIHYCETES. 



cell-sap. Cells of the parenchyma in tiower and stem enlarge to a 
still greater degree. Intercellular spaces are as a rule obliterated, 
but when present are filled with a fine mycelium. Wakker gives 
us further results of the fungoid attack ; crystal-glands, normally 
numerous, are no longer formed, but are replaced to some extent 
by indistinctly defined crystals of calcium oxalate. Transitory 
starch is stored up in large quantity. The fibro-vascular bundles 




Fig. 256. — Exobasidmm vaccinii inducing outgrowths on leaves of Vacciniiim 
Vitis-Idaca. (v. Tubeuf phot.) 

present a striking modification, the primary xylem alone is 
normal, the vessels of the secondary wood remaining rudimentary ; 
other parts are not lignified, and the phloem is only indistinctly 
laid down. 

A mycelium is present in all deformed parts, but absent in 
normal green tissue. It becomes massed to form a hymenial 
layer beneath the epidermal cells or between their outer walls and 
the cuticle. The sterigmata do not exceed four in number, and 



KXOBASIDIUM. 



425 



from each a spindle-shaped spore is abjointed (Fig. 257). The 
basidiospores divide in water by formation of cross-septa, and 
a germ-tube arises from each terminal cell. On a young leaf 
of Vaccinium the germ-tube 
penetrates and gives rise to 
a mycelium (Fig. 258) ; on 
other substrata the germ-tube 
sprouts into se\'eral very fine 
.sterignuita, from tlie extremi- 
ties of which a series of conidia 
are abjointed ; the conidia 
may give off secondary coni- 
dia, perhaps also tertiary. In 
nutritive solution, IJrefeld ob- 
tained an increased number of 
germ-tubes and a continuous 
production of conidia ; in air, 

conidia were produced on conidia, but inside the solution the 
conidia gave off hyphae from wliich new conidia arose. 




Fk:. iitl. — KxohamUvm vaccinii. Tlie basidiul 
layer is shown developing from the interoelhiliir 
nivcelium of the shoots. (After Woronin.) 



J^irr*-^ 




Flii. 2'}$. — Ej'olMtidium vaccinii, Cienniimtint; iKisldionimres. 'I'lii' 8L'|itutc' «|MirfH 
li:ivu (civen off xenn-tulies which iH;netr.ite into the i-owlnrrry leaves, cither by 
stitnmtii or tliroui^h the cpiderniiH. The lowcHt HiM>ro in furniin); eoniiliii. (.Vfter 
Won.nin.) 

This Kni/jKsii/inin is very ("imiiinu mi tlic cnwln-ny ( rdcrininin 
Vitis-Id(ua)} It occurs Irss lr»'i|ut'iitly on ihe l»ilberry (Vac- 



' .SevtTiil .\ini-riciiii Krii'uceiic iire (^ixrii as liDst-pliiiits in the " Jlnsf- liitit x.' 



426 



BASIDIOMYCETES. 



cinium 3Ii/rtiHus)^ causing a premature fall of the leaf aud 
suppression of the flower. The external symptoms of the disease 
differ somewhat from those on cowberry. Diseased leaves are 
much larger than the normal, but are neither thickened nor 
blistered : on the under side they have a whitish or reddish 
coating, and fall off' easily. I have never observed the disease 
on the stems of bilberry. In spite of these external differences, 
it is believed that the host-plants are in both cases attacked by 
the same species of Exohasidium, but I do not know of any 
observations on the reciprocal infection of the two hosts. 




Fig. 259. — Exohasidium rhododendri on Rhododendron ferrugineuui. (v. Tubeuf phot.) 



A disease due to an Exobasidium is Ijy no means uncommon 
on Vaccinium idiginosmn (bog whortleberry).^ Shoots of diseased 
plants are deformed, while their leaves become more or less 
thickened and assume a beautiful rosy colour. 

On Vaccinmm Oxycoccos (true cranberry) the shoots and 
leaflets also become thickened and rose-coloured. Eostrup dis- 
tinguishes this as a separate species {Exohasidium oxycocci). 

Ex. andromedae Peck, produces on Andromeda j^olifolia 
symptoms similar to those just described for the preceding 
species. (Britain and U.S. America.) 

' Sadebeck {Botaii. Ceiitralhlatt, 1886) records it in large <iuaiitity near Harburg. 
This is the host-species given by Massee {British Famjuji- Flora, 1892). 
- Tubeiif , " Mittheilungen." Zeitsch. f. Pjianzenkrankheiten, 1893. 



EXOBASIDIUM. i'2T 

Ex. rhododendri Cram. (Ihitain and U.S. America). Thi.s 
causes t^all-lilo- nutgrowths on the leaves of the Alpine-rose 
{Bhododendroa ferrugincnm and liJt. hirsutum). The swellings 
may be small and fairly hard, or, attaining the size of cherries 
or plums, they may be soft and sijongy so that they shrivel 
up soon after the twig is cut; in colour they are yellowish- 
white, but on the side exposed to sunlight become rose-red : 
the E.'ohasidiinn-^ixWH may even be formed on the small rolled- 
up leaves caused by attacks of mites. 

Ex. Peckii Hals.' [This species occurs in the flowers of 
Andrumidii Mnr'nma in the United States. It is confined 
almost entirely to tiie inflorescences, and causes considerable 
distortion. The bell-shaped corollas are replaced by ones quite 
polypetalous, and the ovary becomes raised abf)ve the re- 
ceptacle] (Kdit.) 

The following five species have been recorded on Ericaceae 
in America : 

Ex. azaleae I't-ik. On Rhodoilfiidron nudljtoruiit. 

Ex. discoideum Kills. On Rhododendron viscosum. 

Ex. decolorans Hark. On Rhododendron viscosum and R. occidenttih-. 

Ex. arctostaphyli Haik. On Arctostaphylos puitycns. 

Ex. cassandrae I'ick. ()ii C'l't.'titndra cdi/odata. 

Other .sj;ecies ti> l)e mentioned are : 

Exobasidium ledi Karst. On Li'dimi pnlnstre. 

Ex. Warmingii Ifo.str. (US. America). This otriirs on Sdrifrdi/n Alzooo, 
S. bri/oidiM, S. axpera, etc. ; it causes marked hyijertmphy of the leaves, and in 
this way, as well as by its many smaller spores, is distinguished from : 

Ex. Schinzianum Ma^n. On the leaves of .SVM'{//7/</(M-ti/««<//A*//«, causing 
whitish sj)uts which soon hecoiue brown and die. 

Ex. symploci Kllis. On SymplociiK tinrtoria in N'oith .\ merit a. 

Ex. graminicolum lircs. On lca\cs of v.irions giasse.s, i:;/. linuuns, 
Arrhi'ii'lthii-iiiii, etc. 

Ex. lauri (ieyl.-is said to produce branched outgrowths of over three 
feel in length on Ltmrns imhilis and L. caiuiriensis in the < 'an.iry Islands. 

I'ri'hii.-n'iliinn roxtnitniii (iliLTn. occurs on the "witches' broom," out- 
growths caused 1>\ T'ljihriiKi conin-i'i-rri (Jhgn. on .\.i/>ii/ii'iii urinhifinn 
in India. 

' Halsted, liulhlin <,/ lh< Tor,; ij C/iih, \\., IS!).!, p. l.tT. 
-IJeyler, lioluii. Ziititioj, 1^7». p. .{--. I'l. \' II 



428 BASIDIOMYCETES. 

HYPNOCHACEAE. 

Hypnochus. 

The mycelium forms a cobweb-like covering on living or dead 
parts of plants. The sporophores take the form of superticial 
coatings composed of club-shaped basidia developed on a felted 
hymenial layer of fungal tissue. Each basidium gives off two 
to six colourless smooth-coated spores from fine sterigmata. 
Some species are parasitic, and cause disease. 

Hypnochus cucumeris Frk.^ In 1882 Frank found at Ikrlin, 
on the surface of withering and dying cucumber-plants, greyish 
coatings of the hymenial layers of tfiis fungus. They occurred 
principally near the base of the stem, and caused its partial 
destruction. The symptoms consisted in leaves becoming rapidly 
yellow from tip to base, and dying off' the plant, the lower 
first. Only cucumbers were attacked, and no further stages 
could be observed on the Icilled plants. 

Hyp. solani Prill, et Del.^ Fine grey crusts, consisting of 
the hymenial layers of this fungus, were found by these investi- 
gators on potato-plants ; there was, however, no injurious effect 
on the crop-yield, 

Aureobasidium. 

Aureobasidium vitis Viala et Boyer.^ The cause of a vine 
disease which has done considerable damage in southern France 
on several occasions since 1882. The grapes when attacked show 
spots, then shrivel up, their interior becoming completely per- 
meated by a colourless septate and branched mycelium. On 
rupture of the epidermis, a firm yellow tissue emerges, and 
thereon a hymenial layer is developed. The basidia are thick 
and club-shaped, with a varying number of short sterigmata ; 
these give off cylindrical unicellular light-yellow spores slightly 
curved in shape and with rounded ends. Leaves are also attacked, 
and fall off' after gradually assuming a deep red colour. If 
this occurs in April, or early in May, the fruit never attains 
any size. 

1 Frank, Hediuigia, 1883; and Berirhte d. de.nUch. hotan. Ges., 1883. 
-Prillieux and Delacroix, Bid/etin de la Soc. mycol. de France, 1891. 
3 Viala and Boyer, Compt. rend. 1891, p. 1148, and xix., 1894, p. 248; Annal. 
de f'Ecole nat. d'agric. de MontpeUier, vi., 1891. 



THELEPHORA. 429 

THELEPHOREAE. 

Thelephora. 

The sporophores of this genus assume very varied t'urnis, IVuiu 
simple incrustations to mushroom-like structures. They consist 
of t\v<j layers only, the middle one being altsent. The basidia 
are club-shaped and produce four roundish or nval, hyaline or 
light-coloured spores. 

Thelephora laciniata Pers. is nut a true parasite, yet it is a 
dangeiiiu> iiKuiuh enemy to trees. In damp situations, it is 
common and thrives, growing over young trees and so env(diii>ing 
them with its sporophores that sullbcation ensues. (Ihiiaiu and 
r.S. America.) 

Th. pedicellata Scliw. lias been reported fnim AiiienVa ' as a daiiiieiuus 
])arasite mi apple, (^nercus coccinea, and a ]talin. 

Th. perdix Harti<f, a parasite on oak-woud. (See Stereinu frost idufsttm.) 
Helicobasidium Mompa. leliik.'- This is injurious to the mulberry tree 
near Ti>kyu, Japan, it first attacks the roots, and in consequence the 
s^rowth of shoots is arrested, tlie young leaves die ott", and gradually death 
of the tree follow.s. The mycelium permeates the tissues of the host, and 
forms an external velvety coating of basidia. 

Stereum. 

Sporophores generally iliflerentiated into three layers, and 
forming leathery or woody encrustations, or tiattened hemi- 
spherical structures attached by one edge only. 

Stereum hirsutum (W.) Fr. White-pi]jfd or yellow-piped oak. 
(Jliiiaiii and I'.S. .\iiifrica. ) A very connnou fungus, occurring as 
a saprophyte on dead braiu-hcs, on boaitls, and posts of various 
kinds of tindier, as well as jiarasitic on llNinu wood, ]iarlirularlv 
on oak. 

The spor(jphores first appear as crusts, later they liccnme 
cup-shaped; externally they are brown and roughly hairy wiiji 
acute yellowish margins. The smooth hymenial layer is orange- 
red and marked by /ones. Uetweeu the sterile leathery sporo- 
ph<»re and the hynn-nial layer there lies a tirm white 
internit'diate tissue. 

' ( ;iilli)WJiy, Jinniial o/ Miiro/niji/, \i., p. Hit. 

-Noliujiro It^hikiiWii, "A new liyiiionomycttouH finigiiH," Juitr. of' CoUnje of 
Sciture. Imperial UiiiverHity, Japan. IHIKJ. 



430 



BASIDIOMYCETES. 



R. Hartig ^ has investigated in detail the phenomena accom- 
panying the wood-destruction in the oak. This begins in the 
branches and extends in white or yellow concentric zones 
throughout the stem, so producing that appearance which has 
given rise to the name " fly-wood." Portions of the wood appear 
only white-striped, other parts have a more regular yellowish- 
white colour. In the white strips the wood has been transformed 
into cellulose and the middle lamellae of the walls dissolved out ; 
that of the yellow parts has not undergone this transformation 
into cellulose, but the destruction has begun from the cell-cavity. 



,1, ir ^' " * 




rm '' ' 



Fio. 2()0.—titrreuiii jn'stulosum. iJestiniction of Oak-wood. l.ongitudinal 
section showing the brown wood with isolated hollow spots containing white 
mycelium, (v. Tubeuf phot.) 

Stereum frustulosum Fries. (Thelephora perdix Hartig).'^ 
(Britain and U.S. America.) The sporophores form greyish- 
brown plate-like crusts with concentric markings ; they are small, 
never exceeding the size of a finger-nail, but generally occur 
in numl:)ers together. The hymenial layer is composed of club- 
shaped basidia beset with hair-like outgrowths ; some of the 
basidia produce four spores, others are sterile and grow on to 
form the hymenial layer for the following year. 

^ R. Hartig, ZersetztC7igserschei7innge7i d. Holzes, 1878, Plate XV^III. 
- R. Hartig, Zei'setzuugserscheinwir/eii, Plate XIII. 



STEREUM. 



431 






. VJiM*.'^ 



■'S:-(^v 



The very characteristic destruction <»f oak-wooil caused by 
this fungus was investigated by II. Hartig. The diseased wood 
has a uniform dark-brown colour, broken at intervals by white 
rounded spots or hollow cavities ; 
hence it receives the name of 
" partridge-wood." In the white spots 
the wood has by the action of the 
mycelium become transformed into 
cellulose, the middle lamellae and 
starch-grains being dissolved out. In 
the neighbourhood of old eaten-out 
cavities the process of decomposition 
is slightly changed, so that the cell- 
walls disappear without previous trans- 
formation into cellulose. 



CLAVARIEAE. 

Typhula. 

Sporophores filamentous, and, as 
a rule, developed from sclerotia. 
Basidia, with four colourless smooth- 
coated sp(ires. 

Typhula graminum Karst.^ This 
ajjpearcd on wheat i)lants in Sweden, 
killing them and forming yellow 
sclerotia {Sclcrotivm fulciim Fr.). 




Later stages of Oak-w«K>d destnic- 
tion. Luavrituiliiial scctinii sliowiuj; 
holes in the timber, (v. TuUeiif 

lll.ot.) 



HYDNEAE. 

Hydnum. 

Sporophores very varial)li' in t'unn and structure. The 
hymenial layei's are spread over teeth-likr pitijcctiKUs. 'I'lic 
basidia bear four white sjtores. 

Hydnum diversidens l"r. - ( I'.ritain). Tlir siH.n)]iliiiics form 
yeliowish-whilt' crusts or brackets, with s])iiiy outgrowths mi 
the lower side. 'I'he hymenial layer consists at first of basidia 
<iidy, hiter, however, hy]>bae L;ru\v up tbiough it and build 

' Krikssoii, Landthr. Akml. HamL v. Tul.kr.. IS7!I. 
-' K. HartiL', Z- rsi l:iiiiiiti rsrlit iiiuinjtn. 



432 



BASIDIOMYCETES. 



over it a new hymeniuiu ; this is continued for some time so 
that the sporophore consists of successive layers, and the spiny 
outgrowths become much thickened. Infection, as was experi- 
mentally shown by Hartig, takes place on wounds. 

The wood-destruction, consisting of a white-rot, was studied 
by Hartig, chiefly on the oak and beech. It begins by the 






.'i^ 



6% 




Fig. 262. — Poti/porus igniarius. Causing death of a White Alder plantation at 
Petneu, Stanzer Thai, Tyrol. The stems bear sporophores, and die from above 
downwards, (v. Tubeuf phot.) 



appearance of yellowish longitudinal bands (not white as with 
Stereum hirsutum), and extends gradually till the wood becomes 
uniformly yellow. The mycelium causes the inner layers of 
the cell-walls to swell gelatinously without previous transfor- 
mation into cellulose, and finally to dissolve out leaving the 
middle lamellae lonsfest intact. 



HYDNUM. 



433 



Hydnum Schiedermayeri ileull. (U.S. America^.. Sporu- 
phores fleshy, with a sulphui-yollow colour Ijoth outside and 
inside, and with a smell (.»t' anise. They occur on living 
apple-trees, less frequently on other species of J^irvs. Accord- 
ing to Schroeter, Thiimen, and 
Ludwig, the mycelium spreads 
through the stems and kills 
the trees. 

Thiimen^ thus describes the 
diseased wood of the apple: "It 
has a greenish-yellow colour, 
which passes over gradually 
to the normal colour of the 
wood : it becomes soft and 
friable, smelling, like the 
sporoplirirc, faintly <>f anise." 

Sistotrema fusco-violaceum 
Selirad. (Britain.) This acronliiig 
to Skiljakuw- is paia.sitic on livinir 
pines, entering by wunnd.s, and 
caiTving destruction throughout 
the wood. 



POLYPOREAE. 

Polyporus. 
>poi-uphores large and 




'k^'.'^ 



Fui. -li'iS. —I'oljijioius ii/;ii((. ii(» on tiak. At 
the iipiicr uiiil i» wcMMl-iiti.'kur'« ncst-hole. (v. 
Tiit>eiif phot.) 



usually shaped more or less 
like a hoof or small Ijracket. 
The sporogenous layer is com- 
posed of cylindrical tubes, 
whi'li generally ttccupy the 
lower surface of the sporopliore. 

The substance between the tulx-s is dilVereul fmrn that nf the 
rest (d' the s])(iro])h(ire. 

Polyporus (Fomes) igniarius (1..).'' (I>ritain antl I'.S. Aintnca). 
SpurM],||,,iC'< 1,11 li\iii;4 >iciiis nt (lak, alder, apple, willow, and other 

'TluiiiHM, •' Kill ApfulljuuniScliadling.' ZiitHch. f. I'jiaif.i idraiikli' it- n. Is'.tl. 
-Skiljiikow, Srri/)/a hotnii. horti unirn-sitatiH Pitrojtolitnnftf, 1890. 
li. Iliiiti)^', Xi ric.tznnijHtrHrhiiiinini' II. I'l. .\\". .uhI .\\I. 

•J !•; 



434 



BASIDIOMYCETES. 



deciduous trees.^ They are brown or grey in colour, tuber-like or 
hoof-shaped, and continue to grow for several years ; the upper 




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1 V. Tubeuf (/'or?.//. -7;.a<Mr«-/.s.s. Zeitschrifi, 1893) describes a plantation of ^/7M(s' 
caiM in Tyrol, which was l)eing killed out by this fungus (Fig. 262). It is 

,.^,...>if>.i ■Ri.iti'al. anopjfc ^TTl/lif \ 



incaua in Tyr.^., ,. ...v..^ ., .^^o .,^^,,^ 
a common Britisli species. (Edit 



POLYPORUS. 435 

side is concentrically marked, and has a stone-liard coatinji; which 
is generally more or less cracked ; several zones and layers of 
tubes will lie found when the sporojihore is cut in section. 

This fungus produces a white-rot in tlie wood, and is one of the 
most common and dangerous of wound-parasites. The wood 
attacked by the mycelium is at first dark in colour, then 
yellowish- white and soft. According to Hartig, a delicate 
mycelium fills up the elements and eats away the inner layers 
of the walls: then the middle lamellae are transformed into 
cellulose and absorljed by it (Fig. 204). 

Polyporus fomentarius (L.) (Fomcs fomentariv.s (L.) Fr.)^ 
(Britain and L'.S. America). " Tinder-fungus." Sporophores 
broad and shaped like reversed brackets or hoofs. Their upper 
side, at first brownish and velvety, becomes afterwards smooth, 
grey, and marked with broad concentric zones. The margin 
is rounded and uniformly grey. The pore-layer is smooth and 
greyish-brown. A longitudinal section shows a homogenous 
tinder-like mass, covered on its lower suiface l)y Layers or 
zones of pores. 

The tinder-fungus is parasitic on beech, elm, and mountain 
maple. It is particularly common in beech-forests, and was 
even more so at one time when the infected trees were allowed 
to remain standing. The sporophores may be found on living 
stems, on remnants of trees broken by wind, and on felled 
trees. For some distance above and below the seat of the 
sporophore runs a furrow on the stem, marking a tract where 
the mycelium has penetrated to the camliium and killed it, so 
that growth in thickness ceases (Fig. 2 (JO, n). 

The mycelium causes in the wood a white-rot of a light 
yellow colour. Where the wood is still firm, though diseased, 
it will be found to be divided into cubical portions by wldte 
tracts of mycelium whicli run both radially ant I vertically. A 
very characteristic feature of the destruction consists uf broail 
white leathery bands of mycelium, formetl in a radial diieetion 
through the wood; the.se are best seen on stems siiatteretl by 
storm, or on wrought timber.- 

' Kusuiii), Tklxskri/i />ri SLorhiinj, 1S8.S. Tiil)ouf, " .MittlK'iliiii>.'i'n." AUnj. 
FniHt-. 11. Jaijil-ZtitttHij, 1S87. A coiniiion |{i-iti.sli .species. (Ktlit.) 

- KruU (.SV-A/e«. Cleji. /. vaterlaml. Kul'., l8!>;{)<liMtiiigui«heH ii jjehitinoUH iiiyceliuin 
ami 11 cuHliiiiii'iiiVt'i-liiiiii. 



436 



BASIDIOMYCETES. 



Tinder, prepared from the soft central part of the thick 
sporophores, was at one time used, with the help of steel and 
flint, for procuring flame. It is very effective in stopping 




Fig. 20.j. — Scene iu the Bavariau forest near liischoffsreut. In the foreground, a living 
Beech with seven sporophores of Polyporus fomentarius. (v. Tubeuf phot.) 

haemorrhage from cut blood-vessels, and is still used in surgery. 
The larger pieces can be manufactured into caps, gloves, vests. 



POLYPORUS. 



437 



and hose. The privilege of collecting the tinder-fungi was 
rented out and regarded as a source of forest-revenue, while the 
tinder-industry was formerly an important one in many districts, 
where sporophores were more frequent and larger than now. 

Measures against this fungus have already heen considered 
in our General Part (§ 12). 




ife M'' 




.-4..v^lH 



mM^^ 




Fig. 2i>t!. — Pohiftorwt fonienlarivs on living Heecli. ", .\ furntw uxtemiinK 
hIkjvu and below the insertion of the sporophore. I>, \u injury proiliiceii l)v 
touring of tiio vuhxX in felling, (v. Tiibeuf phut.) 

Polyporus sulphureus (Hull.)' (I'lriiain niid I'.S. Anurica). 
The HporoplKJics arc Hal and soft, the ujjper side being bright 
orange-red and the lower sulphur-yellow. They last only for 
one year, hence are small; they frciiuiiitly nccui in masses, 
one aljfn-f another in tiers. After deatli ihey lo.se coldiir, 
hecomti lirittle, and are easih' delaehed. Accordilii,' t<» 1 >e 



' H. Hiirti^', /ii.rM&.(-Hii'inerMclitiiiiiii<i> II. A vt-rv rniiiiiiiin Min'cicn in Kritaiii 
(K.lit.) 



438 



BASIDIOMYCETES. 




J I -' ~ —Inlji V I li>hv ti s on a Willow {Sali.f alba) iit Hirschau, near 
Munich (v Tubeuf phot.) 



POLYPORUS. 



439 






Seyiies/ three other kiiuls of spores are produced in addition 
to Itasidiospores. 

^^'illll\v, poplar, oak, sweet chest- 
nut, alder, ash, hazel, pear, cherry, 
robinia, larch, silver Hr, etc., are 
common hosts of this parasite. 

Wood infested by the mycelium 
darkens in colour, exhibiting,' a red- 
rot. Vessels and all clefts or spaces 
become filled with white felted 
masses of mycelium. The wood, in 
course of destruction, becomes richer 
in carbo-hydrates, and tiie walls of 
the wood-tibres shrink so that fis- 
sures with an upward rij^dit to left 
direction are formed, but do not reach 
the middle lamellae. Finally the 
wood becomes dry, brittle, and powdery. 

Polyporus borealis (Wahlenb.) Fr.- (Britain and I'.S. 
America). Spirophores annual, wiiite, and fleshy; the upper 




Fl(3. 21)8. — Poliiporut sutphureu*. 
Hymcnial layer, with biisidiii and 
spores. (After K. H:irtig.) 



/""• 



I 



^ 



\- 



Fi(i. •l<W.~Pol!>i>oi-toi lulpfiurtut. Tbo white luyculiiiiii funiiH oonccntrif r.ouen 
iihil ridial lines nn the crosH-gection of Oak. (.\ftcr l{. nartl^.) 



surface is .sha<;^'y when fresh, ami no internal /ones are e.xhilnted 
The sliajte is somewbiit cu.shioii or braeket-hke, but very varialih- 

'|)i- ."^l;yllt•M, Aililill. ill- Sri. mil.. Sir. I'., \'ol. I., IstJI. 
- K. Hiirtij;. Zi r>iet~unij>trriirh' inuinji n, I'l. \ 



440 



BASIDIOMYCETES. 



many generally grow near each other. The pores have a torn 
margin and cystids are frequent between the hasidia. 

The sporophores are common in spruce plantations, and are 
accompanied by a very characteristic wood-destruction. The 
wood, in the earlier stages, becomes brownish-yellow and inter- 
sected by radial and vertical canals filled with a white mycelium 
(Fig. 270). Gradually, however, it breaks up into small cube- 

f "t . ' Mi'^'* : i-e 








Fig. •27u. — Fuli/jioras boreoJis. Destruction of 
Spruce-wood. The white mycelium is present, 
dividing the decaj-ed wood into cubical pieces. 
(v. Tubeuf phot.) 



. ' 5f 



Fill. :271. — Pohijiorus boreaiis. Later stage 
of destruction. The Spruce-wood is broken 
up into cubical jjieces, and the mycelium has 
disappeared, (v. Tubeuf jihot.) 



like pieces, particularly evident when the wood is broken (Fig. 
271). The cell- walls are dissolved from the cell-cavity out- 
wards, the lignified wall being first converted into cellulose and 
disappearing, finally tbe middle lamella. 

Polyporus dryadeus Fr.^ (P. 'pscuchminiarius Bull.) (Britain 
and U.S. America). Sporophores, annual, large, shaped like 
tubers (jr hoofs, and generally situated towards the base of the 



■■^ R, Hartig, Zer^ttzwKj'^trscheinuwjeii , PI. XVII. A coiniuon Kritish species. 



POLYPORIS. 



441 



steins of oak-trees. At first they are soft, later hard and lirown 
with grooves on the upper side. The dark lieart-wood of the 
oak exhibits white or yellowish longitudinal stripes of rotten 
wood converted into cellulose (Fig. 27- ). In tlie white portions 



&vu,^)c^*^^^-i Mil::: ,r 



i/../,,'^ ' 







Fi<;. •l'2. — t'utif]>oruii Uri/ailtut. The niyceliuiii forms loii^'itiKliiml HtriiiVH 
in the Ouk-\voo<l. (v. Tiibcuf iilint.) 

ihii tlcstructi(Hi is nujrc coiuplftt' than in the- ycllnw, where dis- 
S(jliiti«»n of the lamellae has not as yet taken place (Fig. liTo). 

A simultaneous destruelioii of ihe wood liv /'. ilrifuHnts and 
/'. iijiiin rills may occur ( 1' ig. L'TJ); in this case, [In- nieihdhiiy 



442 



BASIDIOMYCETES. 



rays appear snowy white at tlie place where the t^v■o forms 
of rot meet ; this is due to an accumulation of starch left 
after the cell-walls have been almost completely dissolved. 

Polyporus (Poria) vaporarius (Pers.)^ (Britain and U.S. 
America). The sporophores are white, and have a pungent 
odour ; they form crusts (never brackets) closely adherent to 
dead substrata, especially to beams and other timber in buildings, 



mMvWlk 
I' '■ - 



Fig. 273. — Polyporus dryadeus. Later 
stage of decay of Oak-wood. The darker 
places still consist of firm brown wood ; 
the white, however,' are soft cellulose, 
(v. Tvibeuf x^hot.) 





Fir.. 274. — Polt/jioruK ilri/adeux and Poll/- 
porus igniariiis. Destruction of Oak- 
wood under the combined agency of 
both fungi. The wood is yellowish and 
perforated ; the medullary rays ai-e 
snowy-white, from the accumulation of 
unchanged starch, (v. Tubeuf phot.) 



where this fungus does great harm. They are also found, how- 
ever, on bark of living stems of spruce and fir. The destruction 
takes the form of a red-rot, the wood attacked becoming red- 
brown, cracked, and soft. The mycelium is found in stems and 
roots of trees ; in cracks in the wood and below the bark, and 
on the surface of timber in buildings, it forms fan-shaped strands 
of a permanent white colour. The mycelial strands of the 
" dry-rot fungus " (Mcrulius lacrymans) differ from it in being 



^ Very common in Britain on dead wood, less so on living trees. (Edit.) 



ntLYl'UltUS. 



443 



at first white but becoiiiiiig grey, and in exhibiting an internal 
differentiation whicli those of F. vcqwrarius do not.^ 

The hyphae in the course of their growth do not seek out 
the pits, but grow straight through tlie walls and bring about 
dissolution of the middle lamella for some distance around. At 
the same time numerous short oblique fissures in the walls are 
produced vertically one over the other, especially in the elements 




I'll.. ;:..,. l'u.i,,.tj. u-: .-, ..u...u..;i.. uii .U^. A<.i,ii,;^u. Tho three u])per 8|)orophoro8 
lire borne on a separate piece of wood, from which a fourth ha.-* been cut off. 
(v. Tubeiif j.hot.) 

(»f the thick-wallud autunni wnutl. (t'uuipart* with J', sistofrr- 
miiidis, Fig. 280). The phenomena accompanying destruction of 
wood by this fungus are .so characteristic that Conwentz" could 
<listinguish it (piite clearly in tree-remains enclosed in amber. 

Ihefeld succeeded by artificial culture of the spores, in rai.sing 
a mycelium on wliicii basidia wen* fonin'(l, at lir>t dirci tly. 
aftfrwariN I'min Inrgc sjiorojihorcs. 

Polyporus squamosus (liuds. i. (Britain and I'.S. Annrica.) 

' K. Hiiitig, lUr irfif' /lawsifiiniiiiiii, Htilin (.'^|n•iIl^;;l•^), IS8.'». 
- ('itiwwul/., Miiiioiirdjifiir ,1. I,ii/li-rlii II /li rimfi iiihii iiiin , I.SlHt. 



444 BASIDIOMYCETES. 

Sporophores annual, occurring from spring to autumn ; at first 
tender and fleshy, later leathery or almost woody. In form 
they are short-stalked, flat, semi-circular or kidney-shaped, and 
attached by one edge ; they may also be stalked and circular 
or cup-shaped. Their upper surface is yellowish, with flat brown 
scales arranged in concentric lines. The hymenial layer is 
continued well on to the thick fleshy stalk of the sporophore ; 
it is yellow in colour, and consists of short angular pores. 



/* 










Fig. 276. — Pobiporui hispidus on pieces of living Ash. (v. Tubeuf phot.) 

The spores are spindle-shaped and colourless. The fungus is 
especially common on living hazel, ash, species of maple, beech, 
mountain ash, horse-chesnut, elm, oak, willow, pear, lime, etc. 

The wood of the specimen in Fig. 275 exhibited extensive 
white-rot, the inner parts Ijeing completely converted into a 
soft wliite spongy mass of mycelium. 

Polyporus hispidus (Bull.).^ (Britain and U.S. America.) 
Sporophores annual, soft and spongy, with a rough brown upper 

^A very common form on ash trees in Biitain. (Edit.) 



POLYPORUS. 



445 



surface, and a smooth yellowisli liyinenial siiiface. Tliey are 
large and Jiat, the thickest part being at their insertion 
(Fig. 277). Several frequently occur on the same stem, especially 
if wounds or frost injuries are present. The spores are brown 
and roundish. Conidia are said, by Schroeter, to be formed on 
the upper surface of the sporophores. 

This species is a deadly enemy of fruit-trees, especially 
apple. In the vicinity of Munich the sporophores are common 
on ash. Schroeter gives elm and plane as hosts, and Prillieux 




Kio. 277. — totyporus hi»pidii». l^ongiludinal section through a living stem of 
A»h, and a sporophore of P. hiijiidvu. Tlie stem shows symjitoms of wood- 
flcstniction, in that it Itecomes brown antl has sliort white lungltiuiinal and 
radial stripes, (v. Tubeuf phot.) 



and Delacroi.K state the fungus to be very dangerous to the 
mulberry in France. 

It causes^ brown discoluraliuu nt' tluj wuuti accoiiiiiaiiii'd liy 
characteristic short white lines in both radial and vcrtiial 
dircciidiis. so that tlif wiiod liccniin'S nuirkeil out in s(juart's. 

Polyporus (Poria) laevigatus Fr.- Spuiojjhnres dark-bntwn 

' I'rillieiix tJin/l'l. <h In Sor. //lyro/o;/. ./. Fniiir, , IV., Isii;}), gives ilcUils of 
the WfHtiiictiriii <)i tlic wood. 

-Miivr, Jiofdii. ('>ntni/l>/<if', \ix., IHSJ. 



446 



BASIDIOMYCETES. 



aud forming crusts on the l3ark of birch. Spathulate cystidia 
occur between the basidia. Spores colourless, and acutely ovate 
in shape. 

This is parasitic on birch. The mycelium kills and permeates 
the wood-parenchyma which forms the greater mass of the 
later-formed parts of each year- ring, with the result that the 
various year-rings of the wood separate from each other as 
concentric hollow cylinders. The mycelium varies according as 
its pabulum consists of cells just killed, or of wood, or of 
elements in the last stages of decomposition ; in this latter case 
it suffers from want of food. In woody elements in contact 

with air, or those destroyed 
l:)y Polyporus hctulinus, the 
mycelium is brown and 
forms vesicular tyloses 
similar to Ar/aricus metlcus. 
Polyporus betulinus Fr. 
(Britain and U.S. America). 
The sporophores are annual, 
and emerge as spherical 
structures from the unin- 
jured bark, or from bore- 
holes of Beetles, or other 
wounds. When mature 
they are hoof-like or semi- 
circular and short-stalked ; 
when dead they become 
soft and break off'. The upper side is light-brown in colour, the 
pore-layer is white. A section through the sporophore shows it 
to be white and homogeneous without zones. Lanceolate cystidia 
occur between the basidia. The spores are rod-like. The pore- 
layer and the upper brown layer are easily detached, and strips of 
the remaining tissue are sometimes utilized as razor-strops. 

This parasite frequents living birches, ultimately causing death. 
It is known to occur on both Bctida verrucosa and B. pubescois 
in Britain, America, and Europe. Its parasitism and injurious 
results were first demonstrated by liostrup.^ Mayr^ investigated 

iRostrup, •' Snvltesvamper Aiigreli paa Skovtraeerne," Tldsskrift pa Skvr- 
bunj, 1883. 

'-Mayr, Botan. Centralhlalt, xix., 1SS4. 




Fig. 278. — Polyporus betulinus on Betula verrucosa. 
The sporophore was developed horizontally on a 
fallen stem ; it is here, however, set up vertically 
and photographed from the lower side. (v. Tubeuf 
phot.) 



I'OLYl'URUS. 447 

in greater detail the destructiun brought about liy its luycelium. 
He found that it penetrates lignified cell-walls, entering the living 
elements and causing their death; it spreads most rapidly in the 
vertical direction through wood, bast, and rind, growing through 
parenchyma and sieve-tubes, and even boring its way into the 
sclerenchymatous stone-cells; it absorbs the secondary tliickening 
by dissolving out first the ligneous incrustation, next the cellulose, 
while tlie middle primary lamella remains behind untouched. 

Pol3rporus (Fomes) fulvus (Scop.) (Britain). Sporophores 
woody and very hard, at tirst hairy but later smooth, dark, 
and cracked ; in form they are tuberous or triangular. In- 
ternally they show no stratification. The fungus is very common 
on living plum where it causes undoubted injury ; it also occurs 
on hiirubean and aspen. 

Polyporus fulvus var. Oleae Scop. In northern Italy 
may be fre(|uently observed a peculiar splitting of the stems 
of olive trees into two or more portions ; the fissures occur 
generally on the lower parts of the tree, and may extend so 
deeply that the stem appears to stand on stilts or prujis. 
Hartig ^ ascribes this phenomenon to the presence in the olive 
stems of the mycelium of Fohipurvx fulvus causing rotten places 
which are cut out by the Italian cultivators ; the disease, how- 
ever, continuing to make progress, it may be necessary in course 
of time to cut s<j deeply into the stem, that tracts extending 
right through may be removed ; this takes place all the more 
rapidly if several diseased spots are being simultaneously 
operated on. The destructi(jn of tlic olive-wood by tliis i)arasite 
is simihir to that produced by J', iijniarius on oak and other 
trees. The sporophores appear on rotten spots, but are gener- 
ally quickly removed V)v the cultivator. Infection takes i»lace on 
wounds, hence it is advisable at once to a]»i)ly tar after cutting 
out any decayed wood, and also to paint ])nining-cuts or other 
exposed surfaces with tar. Neighbouring fiuit-trees, liable to 
sutler from this .same fungus, shoidd be similarly treated, both 
for their own safety and thai of the olive trees. 

Polyporus Tomes Hartigii .Mbsclicr -' (/'. i>fjti<irius mr. 

' [[. Il.iitig, " l)if S|i;iltuii),' ilcr Oi-lliaiilm-. " Fo)-ntlir/i-iin/uririss. 2iittrfir(f't, 

I s'.i;;. 

- K. Hiutii.', Zi rxttzuiidMifsfhi iiiniiiji II, I'l. \'ll. /•'«c«^//i7i-h(/<h/vcis<. Ztil- 
Mcfiri/t, IHiCf, ],. til. ' 



448 



BASIDIOMYCETES. 



pinuum Bresadola or P. fidvus Scop, of li. Hartig). Sporophores 
on silver fir, less commonly on spruce. Their form varies much, 
according as they occur on a branch or on the stem. In the 
former case, the sporophore forms a swelling below and on each 
side of the more or less horizontal branch. On the stem they 
are more or less bracket-like. The sporophores are reddish 

brown with a smooth upper surface on 
which zones are only faintly indicated 
(jr altogether absent. Internally they 
are of a brownish or tawny colour, and 
exhibit concentric strata, which, do not 
extend into the pore-layer; they are thus 
distinguished from sporophores of P. 
igniarius and others. The sporophores 
are very frequent on cankered stems of 
fir where the canker-spots afford easy 
entrance for the spores. 

The wood-destruction consists in a 
white -rot. The wood becomes yellowish- 
white with clear spots and fine dark 
lines, especially where in contact with 
healthy parts. The mycelium is yellow- 
ish, and consists of thick hyphae with 
lateral- branches forming tangled masses 
which frequently fill up the cavity of 
the bordered pits. This mycelium gives 
off very fine branches which bore through 
the cell-walls and dissolve them in such 
a way that the middle lamellae disappear 
first and leave the remainder of the wall- 
thickening for a time isolated before it 
too is used up. In this way large holes are formed in the 
elements of the wood. 

Polyporus sistotremoides (Alb. et Scliw.) {P. Schweinitzii 
Fr. or P. mollis Fr. of li. Hartig)-^ (Britain). Sporophores almost 
circular with a short thick central stalk ; while young they 
are light brown and spongy, but when older become dark Ijrown 
and corky. The upper surface is downy ; the hymenial layer 
extends far down the stalk, when young it is yellowish green, 

' R. Hartig, Zersetzungserscheinunijen, PI. IX. 




Fig. 279. — Poli/poriis Hartiqii. 
Destruction of wood of Silver Fir. 
The decayed wood is yellow, but 
shows dark points and black lines, 
(v. Tubeuf phot.) 



POLYI'OKUS. 



440 



but later becmnes brown, aiitl, on IteiiiL; tcjuchud, tlt'fi) red. The 
spores are white, and various forms of hairs occur anionic the 
basidia. Young sporophores appear as little brown cushions mi 
felled timber, also on living stems of pine, and, according to 
Magnus, on Weymouth pine. 

The disease generally makes its first 
appearance in roots and lower parts of the 
stem, spreading thence into higher parts. 
Diseased wood has a characteristic odour of 
turpentine : it has a redd i.sh- brown cohnir, 
and, as destruction proceeds, it gradually 
shrinks and disintegrates till it liecomes so 
soft as to be easily powdered between the 
fingers. Where broken over, the wood is 
often covered with a thin white coating of 
mycelium incrusted in resin so as to appear 
like chalk. 

The mycelium penetrates the cell- walls 
in all directions. A very characteristic 
feature of this parasite is furnished by 
shrinkage-fissures in the thick walls of the 
tracheids of the summer-wood (Fig. 280). 
These are numerous and run ujjwards from 
right to left extending through' the whole 
wall to the outermost layers. They differ 
from the fissures in tracheids destroyed by 
P. caporariu.s, in that they run round the 
whole circumference of the cell, instead of 
being small and set vertically above each 
othei'. 

Polyporus (Fomes) pinicola (Sw.) (U.S. 
Ameri(;i). Spiiruphores thick, hoof-like or 
liracket-shaped, with a smootli dark-grey up])er side and a bright 
red rounded margin. Tiie hymenial layer is smooth and yi-lldwisii, 
tlie spore-powder white. In section the sporoiihore.s are white. 
Tlie species is fn'([uent nn living stems nl' sjiruce, pine, and lir, 
aNo on hir'-li mid cliciTy. 

Polyporus iFomes) marginatus Ki. (I .s. AnuTica). Spom- 
ph'jres with red margins, and otherwise very like those of the pre- 
ceding sjK.'cies, yet generally mueh larger, ami more extendeil. 

■1 V 




Fio. -JSO. — Tracheid of 
ri/iiMdestroyed by Puly/ioru* 
fiMtoti-niioUltf. The celhilose 
li:is been for the umst imrt 
cxtnieted, and the wiUU con- 
sist of ligiiin (wt)iHl-giini). 
Cr.icks ofc-iir in the dry 
secondary wall, while the 
wall {(I, Ij) remains intact. 
The spiral .structure of the 
secondary wall causes cross- 
ing; of the tissurcs in the 
walls of adjoiniu); cells at 
the liordered jiits, c. ami at 
Ixire- holes, J, e ; where 
neither jnts nor holes are 
present the fissures are 
simple,/. (After H. UartiB.) 



450 



BASIDIOMYCETES, 



The two species are held by many autliors to be identical. 
It occurs chiefly on stems of beech, also on oak and birch. 
In regard to its parasitism nothing further is known. 

Polyporus (Fomes) annosus Fr. (Trametes radiciperda 
Hartig^) (Britain and U.S. America). The sporophores vary 
much in form, according as they occur more above or more 
below ground on tree stems, or on timber in mines. The 
upper surface is brown and marked in zones, the margin being 
lighter. The section through the woody sporophore is white. 
The hymenial layer is also white. Spores ovoid and colourless, 
germinating easily in water. In artificial cultures, Brefeld 
states- that they produce only conidia. 




Fig. 281. — Polyporus. annosus Fr. (Trametes radiciperda Hartig). Stool of a 
forty-year Spruce, which has been dead for two or three years. The sporophore 
is several years old. a, a, White open-pored layer forming over the dead basidial 
layer, b, b; at c a narrow strip of wood still remains firm, the remainder is 
completely destroyed and rotten. (After R. Hartig.) 

This species was first investigated in detail by Ii. Hartig,^ 
and is described by him as the most dangerous of all parasites 
in the conifer forest. It is most frequent on Conifers, e.f/. pine, 
Weymouth pine, spruce, silver fir, Douglas fir, balsam fir, 
juniper, and Thuja ; it also occurs on various broad-leafed trees, 
e.g. beech ^ and hawthorn. 

^R. Hartig, Zersefzungserscheimaigen, PI. I. -IV. Wichtige Krankheiten, PI. 
III. Ztif-schri/t f. Forst-und Jagd-ivesen, 1889, p. 428. Botan. Centralblaf/f 
XLii., 1890. 

-Brefeld, Schimmelpihe, Heft 8, 1889. 

* Rostrup, Afbildning og Beskrivelse af de farligste Snylteiivamfe, 1889. 



POLYPORUS. 451 

The mycelium penetrates both bast ami riml causing a very 
acute red-rot in the wood, so that death of the tree attacked 
rapidly follows. The disease makes its appearance on plants 
of all ages, and in forests of spruce or pine causes gaps 
which rapidly extend in a centrifugal direction. The roots 
and lower parts of the stem are generally the parts first 
attacked. On the roots, the parasite is easily distinguished, 
even in the absence of sporophores, 

by the very delicate white mycelial «r— — t — — . •■ ..{ 

membranes formed between the 
bark-scales. Destruction of the 
wood becomes first evident Ijy the 
appearance of vertical dark lilac- 
coloured stripes indicating the stage 
when the parenchyma cells are 
killed. At a later stage, the wood i ' . 
becomes Itrown, and shows isolated ' 

black spots with white margins 
(Fig. 282). These last con.sist of 
coils of dark mycelium surrounded -. , 

by wood from which the incrusting ri.,.:;-j. y. ,;,._., i..- ..,',..,,.,.. n.-tiuc 

' , , 1-11 tion of Sprucf-wood. Lontatudinal sec- 

substance has been dissolved away, tion showing wiiito(ceiiuio8e)six.t.-*witii 

, . , n 1 Ti t' black (iiiyceliuiii) centres, (v. Tiibcuf 

leaving only cellulose, readily tns- i,hot.) 
tinguished by turning blue on 

treatment with chlor-zinc-iodine ; here too, the middle lanielliie 
are ultimately dissolved out, so that the elements become isolateil. 
A colourless mycelium may al.S(j be found in the other parts 
of the wood, l)oth inside the elements, and extending in all 
directions through the cell-wall, lea\ing holes where it itself 
has disappeared. Di-S.solution of the lignifying substance })io- 
ceeds from the cell-cavity, the middle lamella remaining 
intact till the last. The resin of the decayed wood passes over 
into all healthy jtarts and tlows from the l>ark of ili.seased 
stems as a resin-tlux. 

The most elVective metho(l for (■(.mbatiiig the ia\ages of 
this parasite is isolation (»f infected areas. In one ca.sc which 
I investigated in leaden, several spots in the fori-st formed 
very eviijent starting imint.s, and sporojihoies were everywhere 
present at the base of stems amongst the nio.ss. Sucii spots 
should 1 m-losetl l»y ditches with verlieal siiles, and deep 



452 BASIDIOMYCETES. 

enough to cut through all roots, care being taken to leave no 
diseased stems or roots outside the circle ; after remaining open 
for a time, the ditch must be refilled with soil to prevent 
development of sporophores on the exposed roots. Diseased stems 
should be felled, and, along with all root-remains, burned on 
the spot, where there is no risk of forest fire ; failing this, they 
and their stumps should be deeply covered over with soil, to 
prevent development of sporophores. 

The following species of Pulf/porns have been observed on 
Jiving trees, but details in regard to their parasitism and mode 
of destruction are still wanting : 

P. officinalis Fr. On laix-h, chiefly in Russia, but also in France and 
Switzerland. The sporophores are white irregular masses, and at one time 
were used in medicine. The mycelium forms bands in the wood similar 
to those of P. sulphureus. 

P. albus (Corda), according to Ludwig^ is a cause of a disease of Conifers, 
which extends from the I'oot uj^wards. (U.S. America.) 

P. spumeus (Sow.). On apple trees. (Britain and U.S. America.) 

P. fumosus(Pers.). On willow, ash, majale, and other broad-leaved trees. 
(Britain anfl U.S. America.) 

P. picipes Fr. On willow and other broad-leaved trees. (Britain and 
U.S. America.) 

P. (Fomes) cinnamomeus Frog. On cherry trees. (Britain.) 

P. radiatus (Sow.). On alder {A. incana), birch, and beech. (Britain and 
U.S. America.) 

P. (Fomes) ribis (Fr.). On black currant and gooseberry shrubs. (Britain 
and U.S. America.) 

P. (Polystictus) hirsutus Fr. (Britain and U.S. America). On living 
hornbeam, alder, oak, birch, and service. A variety, scruposus, is common 
and injurious on cherry. 

P. ulmarius Fr., is, according to Cavara,- parasitic on living elm near 
Pavia. (Britain and U.S. America.) 

P. (Fomes) nigricans. On birch. (Britain and U.S. America.) 

P. salicinus (Pers.). A dangerous enemy of willow.' (Britain and U.S. 
America.) 

Rostrup^ gives Corticium comedens as a wound-parasite of oak and 
alder. 

Hartig describes Fistulina hepatica, the liver-fungus, as causing a dark- 
brown colour in oak-wood. 

1 Lndwig, Lehrbuch d. niederen Krypfogamen. 

-Cavara, Revue My col., 1891. 

^Tursky, Russian translation of R. Hartig's '^ Lehrhurh d. Baumh-anhheitcn." 

•*Rostrup, Fortsatte Undersoijel'ier, 188.3. 



TRAMKTES. 453 



Trametes. 



Sporophores as in Puli/jjunin, except that the sulistance 
between the pores does not differ from that of the rest of tlie 
sporophore.^ 

Trametes pini (lirot.) Fr.- King-scale of Pine. This is a 
dani^eruub turcsL parasite in Xorthern Germany ; also in Britain 
and U.S. America. On the pine the sporophores develop from 
branch-scars, and assume a bracket form. The fungus has also 
been observed on spruce in Bavaria and elsewhere, but in this 
case, the sporophores are more frequently found as a coating 
over the bark on the under side of a branch. Larch, silver 
fir, and the Douglas fir (in America), have also been mentioned 
as hosts. 

The sporophores are brown and woody, and continue to i'orm 
annual hymenial zones for a numl»er of years. The hy menial 
layer con.sists of pore-tubes lined with basidia, between which 
thick-walled cystidia are formed. The spores are elliptical, and 
on germination penetrate into wounds or broken branches not 
protected by an outHow of resin. The older branches of pine 
and larch have a central heart-wood from which no resin is 
secretetl, and these branches, when broken over, otter the neces- 
sary acc(;ss to the germinating spores : for this reason, infection 
takes place most frequently in <'M ])hintations. The mycelium 
spreads through branch and .stem, particularly upwanls ami 
downwards in the same year-ring. In this way longitutlinal 
stripes and peripheral zones are formed in the wood, giving rise 
to the ])Opular name "ring-scale." Single hyjiliae bore through 
the cell-walls, and a ferment secreted \>\ tlicui dissolves 
tlie incrusting substance, so that walls allected show iJic ic- 
actions for cellulose almost at once. A very characteristic 
feature is the appearance of isolated white spots or holes, iiuli- 
cating where the wooil, alter becoming celluhtse, has l)een 
dissolved out entirely. riie middle lamellae are dissohi-d out 
first in attacks of this fungus, ijie tertiary lamellae remainim.' 
longest intact (Fig. \'l). The dark cenlres of iiiyecliuni iii-i'lf 



' 'I'lif (liHliiictioM lietwceii till' j(eiiuia /'i>/i//>i>iiis iiml 'J'lfuin/' ■< i« Imtlly ili'tiiu'<l. 
A rein vest igat if m of tlie syHteiimtic rt'latiitii.s|ii|iM <>f tlu- wlioU- lii-iiiipof l'<i|y|><)ti'at' 
woiilil ill fuct )>e ailviHuhle. 

-I!. Hartij{, ZiritlziiiiiiierMr/iiiititiiijfii, I'l. \'. iiinl \ 1. ; W'uhtiij' Kritukh'itni. 
\'\ III ; Lf/irliiir/i il. lianmkraiikhiih II, IS'M i Knjiii.sli truiiHlation l>y Sdnifrville). 



454 



BASIDIOMYCETES. 



white wood-spots, so characteristic of Pulyporus annosus {Tram, 
radiciperda), appear only rarely in this species. 

The destruction of spruce and fir goes on from pith to 1 lark ; 
in tlie pine, however, it seems to be confined to the heart-wood, 




Fig. 283. — Trmiietes pini on Spruce (Picea 
cxce.lxa). Sporophore on the stem beneath a 
snag-branch, (v. Tubeuf phot.) 



Fig. 284. — Traiiutcis pini on Spruce. 
Board showing the characteristic 
white ceUulose-spots in the wood, 
(v. Tubeuf phot.) 



and is prevented from entering the sap-wood by a firm zone 
permeated with resin. 

Kemedial measures are the removal of all diseased stems 



TllAMETES. 455 



at thinning: and the prevention of unnecessary injuries to living 
branches or stems. 

Trametes suaveolens (L), common on dead willow, is also 
reported as parasitic on living stems. (liritain and I'.S. America.) 



AGARICINEAE. 

Agaricus. 

Sporophores umbrella-shaped and Heshy, and decaying soon 
after discharge of the spores. Hymenium on the under side 
of the umbrella, and spread over a series of radiating gills or 
lamellae, easily divisible in a longitudinal direction. 

The genus is divided into sections and subgenera distinguished 
by the colour of the spores; the Coprinavii are black-spored : 
the spores of the PratiUi are dark purple, brownish-purple, or 
dark brown; oi the Dennini brown, yellowisli-lirown, or orange: 
of the Hjiporhodii rosy or salmon-coloured: of the Lcucospori 
wliitc. 

Agaricus (Armillaria) malleus Vahl.^ dhitain and r..s. 
America.) The honey-fungus or " liallimasch." The sporophores 
are present in nundjers towards the clo.se of summer on tree- 
.stools of all kinds, and on the bark of dead or living I'onifers : 
also on tindjer, and even on earth. The Hesliy stalk is somewhat 
thickened towards its liase, and towards the u)>per part bears 
the membranous yellowish annulus (Fig. 2X0). The cap sur- 
mounting the stalk is honey-coloured or brownish with daik 
scales. The spores are wiiite and bestrew adjacent objects with 
a mealy dust. Tiie sporophores are edible. 

Tiic' connection between the sporo])hores and the rhi/oinor]ih- 
strands was jiroved l)y Hartig. These rhi/.omorphs are very 
common and vary much in form ; they oeeur as round brown 
strands runinng ihinugli tlie earth fioni root to root of attacked 
trees; inside hollow stems and in wooden water-jiipes, they 
retain their rounded form, Init under the bark of trees thev 
become dark brown Ihittened liands (Fig. L'SS). Thry are not 
uncommon on timber: in mines they may lie frei|Ui'ntly 
seen hanging from the woodwoik as tangled elumjis, with 

' \i. Iliiitii;, lyi'/i'i'/i Kidiiklii il' II, I'l. I. iiml II.; /.> r^i l-.tiini^i rscli- iiiuiuf n, 
I'l. \i. I). I'.aiy, liotitii. Z.iliiii.i, |S.-.!I. Ki-.-fcl.i, SrfiimiiK //»/-.', il.fi. m., |S77. 



456 



BASIUIOMYCETES. 



numerous branches like the runners of some hanging plant, c.y. 
Aaron's Beard (Sa.mfraga sarmentosa). The rhizomorphs live as 
saprophytes and have been long known to emit phosphorescent 
light. Sporophores are developed directly on them, and if one 
sows the spores, a delicate hyphal tissue is produced, which, 
under suitable conditions, passes gradually over into the rhizo- 
morph-strand. Brefeld succeeded in raising rhizomorphs from 
spores in artificial nutritive media. 



yi V^>9^'^;. 






















»V-*.' 




Fio. 2S5. — Agaricus mclleus near a Beech-stool, (v. Tiibeuf phot.) 



The ^_i7«ric2<s-mycelium forms fan-shaped snowy-white firm 
membranous expansions under the bark of newly killed or still 
living trees. They are quite distinct from the much more delicate 
mycelial expansions of Polyporus annosus, and offer a particularly 
easy means of distinguishing between the two species. Another 
indication of Agaricvs is the great outflow of resin from the bark 
at the base of the stem and from roots, whereby hard clumps of 
earth are formed round the roots. The passage of the rhizomorphs 
into tlie white membranous mycelium is easily observed. The 



AGAKICUS. 



457 



rhizomorphs distribute the fungus in the earth and otlier dead 
substrata, as well as bore into the bark of healthy Conifers. 

This parasite attacks not only the indigenous Conifers (spruce, 
silver fir, pine, larch, and juniper),' but also the introduced 
forms — Weymouth pine, Douglas Mr, Pinus rigkla, Abies Piclita, 
Ficca sitchensis, various CKpressincae, etc. It also seems to attack 
broad-leafed trees, at least as a wound parasite.- 

In regard to the interesting structure of the rliizomorphs, 
and the characteristic mode of wood-destruction caused bv 




Fig. •2>ili.—.4iiari'<-UK iioU'Iik. Siioroplmti.- 
cluvelcji>ed from a rhizoiiiorph-stniiui ; the 
other branch lx.'.ir8 arrested sporoiihores. 
(After K. Harti^.) 







Fi(i. 287. — AjHii'lnin iiietteun. Seetiini 
through a lamella. (/, The hypliae forming 
the siibstmee of the lanielLi arc much 
hraiiched, and send twigs outwards which 
end in cluV>-8haped basidia, a ; on many of 
these are developed stcrigmata with apiees 
swollen into sj>ores, li; <•, isolated thread- 
like arrested Ixisidia projecting aKtve the 
liynienial layer, (.\fter K. Ilartig.) 



tiiis fungus, I give directly the accDiint by Ilaitig in his 
" Li'hrbuch." ^ "The pathological .syniptoiiis can only be ex- 
plained in the light of the })cculiar oigani/.atirtn of the mycelial 
growth that li\cs in the cortical tissues. Tiic apex nt' the 
rhiz(jiiiorphs consists of delicate ])S('udopai-ciicliyma, which, 
ehjiigaling by the division and growth of the cells, j)roduces 
delicate hyphae on the inside at a certain distance trnm the 

'I fouinl it on juniper in tlie piiio-forests near KI»c'r.sMiiltlf. (Aufli.) 
- The niycfliuni <l<u;>i not seem capalile of penetriiting iininjureil l>r<>ail-leuveil 
tree.s, l)Ut li. Ihivtin (For'<//.-iiitt unrigs. Ztilarhriff, 1S94, p. 42S) mentions attack 
an<l ileath of cut roots of healthy oaks. 

^ R. Hartig, Lihrlnirh il. /iiiiimkntidln itm, 1MS!». Tlie translation given 
here is from I'rof. Somerville's Knglisii edition of Hartig's te.\t-lMH>k, p. 
210. (K.lit.) 



458 



BASIDIOMYCETES. 



point, whereby a felted tissue, called the medulla, is produced 
in the interior. The outer parts of the pseudoparenchyraa, on 
the other hand, coalesce to form the so-called rind, which when 
young gives off numerous delicate hyphae, and these, taking 
advantage of the medullary rays, penetrate the wood, and 
especially the resin-ducts, should such be present. In the wood 
the growth is upwards. This filamentous mycelium, which pro- 
gresses much more rapidly in the interior of the wood than 
the rhizomorphs whicli grow in the cortex, completely destroys 




Fig. 288. — Apai'icus hielUus. Rhizomorphs in the form of dai'k atiastomosing 
bands, developed between the bark and wood of a tree. (v. Tubeuf phot.) 



the parenchyma that exists in the neighbourhood of the resin- 
ducts, and to all appearance this is accompanied by a partial 
conversion of the cell-contents and the cell-walls into turpentine. 
The turpentine sinks down under its own weight, and in the 
collar, where the cortex is withered, having been killed by 
rhizomorphs, it streams outward, pouring partly in between the 
wood and the cortex, and partly into the surrounding soil at 
places where the cortex has ruptured owing to drying. On 
this account the disease was formerly called ' IJesin-flux ' or 



AGARICUS. 459 

' Kesin-glut.' In the upptT parts of the stem, where tlie eiiinbium 
and cortex are still sound, the turpentine also tiows laterally, 
by means of the ducts of the medullary rays, from the injured canals 
towards the cambium and cortex. In the latter this accumulation 
induces the formation of large resin-blisters. When, during the 
summer, the cambium is forming a new ring, the plethora of 
resin has the effect of causing the production of numerous resin- 
canals, which are usually large and abnormally constructed, and 
these impart to the wood-ring formed during the year of sick- 
ness a very striking and characteristic appearance. 

" The mycelium gradually spreads from the cells of tiie 
medullary rays and from the resin-ducts into the vascular 
elements of the wood, where it produces a form of decay which 
may be termed a variety of white-rot. During the progress of 
the decomposition from the surface of the stem inwards a certain 
stage is reached, which is highly favourable to the development 
of the mycelium. While previously it was simply filiform and 
furnished with numerous lateral hyphae, it now develops large 
bladder-like swellings, and at the same time the hyphae change 
into a kind of large-meshed parenchyma, which, like the tyloses 
in tlie vessels of many dicotyledonous trees, completely fills up 
the lumina of the tracheides, On account of the mycelium 
assuming a brown colour when in this condition, it makes the 
portion of diseased wood which it infests appear, to the naked 
eye, like a black line. As this kind of mycelium soon dies 
off" and is dissolved, being replaced by a delicate filamentous 
mycelium, it seldom happens that tlic /one which it occupies 
exceeds the breadth of three to four trachcids. The walls of 
the elements of the wood afterwards display a cellulose 
reaction, and speedily di.ssolve tVoui ihe lumen oiii wards. 

"On account of the trees drying up, alU-r the rhizinnorphs 
have s])read from the point of infection on the roots into the 
stem, and again from tlu,' stem into the hithrrto s((und roots, 
decomposition (jf the stem usually ceases liefore tiie mycelium 
has ailvanced from the alburnum into the duramen. It is only 
in tlic stool and roots that decay rajiidly sjpii-ads through"Ut 
thi- whole of the wood. " 

-Methods for cxtcniiinating tliis parasite are uiikimwii, lieymiil 

removal of diseased plants and eoneetidli ui spuruphi iies. It 
woiilil eertainlv be advisable not to plant yoinig <'(>nilers un 



460 



BASIDIOMYCETES. 



cleared forest-land where the fungus sporophores are numerous 
on dead stools or roots. 

Agaricus (Pholiota) adiposus Fr.^ (P]ritain and U.S. 
America). This is a conspicuous bright yellow or honey-yellow 
toadstool, with a glistening slimy cap which, as well as the 
stalk, is beset with concentric darker scales (Fig. 289). The 
scales and delicate annulus become indistinct or disappear on 
old sporophores or after much rain. The stalk is thick, fleshy, 
and stiff, and while growing so changes its direction as to keep 
the cap always in a horizontal position. The pileus or cap, at 




Fig. 289. — Agaricus adiposi/s. A, A mature and a very young sporophore grown 
in the forest ; the other sporophores were raised on Fir-wood in a cellar. The 
latter have longer thinner stalks, and a basal swelling beset with white down. 
B, Mature and germinating spores, (v. Tubeuf del.) 



first globose, opens out cone-shaped or flat with a diameter of 
about 5 cm. Eemains of the velum adhere to the margin. The 
underside of the cap is at flrst yellow, later mouse-grey. 
The lamellae are of three sizes, the largest extending from 
margin to stalk. From the lamellae arise the basidia, with 
four sterigmata each giving off a single spore. The spores 
fall at maturity, and cover neighbouring objects with a brown 
dust. They are oval with a length of 7-1 0^ and a breadth 
of 5-6/x. 

The sporophores spring up rapidly in large numbers on 

' V. Tubeuf, " Eine neue Kranklieit d. Weis.staune." Zeifftchr. f. Forxt u. Jafjd- 
wesen, 1 8!)0. 



AGARICUS. 



461 



living steins of silver Hr, beech, etc., and on t'elled wood/ In 
the forest, on newly erected piles of firewood, the yellow stools 
may frequently be found in every stage of development growing 
from the cut billets, while they are especially numerous on the 
rotting useless timber left Iving. In cellars tjr other moist 




Fi(i. 2'JiJ. — .-/yiiiicu^ aiiijiOMU:!. Destruc- 
tion i)( Kir-wood. The deeiily-turrmlcd 
cross-tissuruM contain white mycelium ; the 
remainder of the wood iH yellow, (v. 
Tuheuf phot.) 




Fl(i. 291. — Affuricui aJijxmag. Destruc- 
tion of Fir-wood. Later stage. The 
corroded fissures no longer contain my- 
celium. (V. Tubeuf phot.) 



chainber.s, the si)oi()i)hores may be abundantly produced till 
Cliristmas, but out-of-doors, August is the time of friiclilitalion. 
The mycelium forms felted masses uiKk'i- the bark m in crack.s 
<jf the wood, and thence the sporophon-s arise a.s liiiU' j)ah'- 
yellow buttons, which grachially unfold and become din'ereuliated 
into cap and .stalk. Wbib- (|iiilc vouiil,', they sbuw the darker 



' l'iovioii8 to tlic puliliciitioii of v. Tiil)fiifH iiivi-sti^'iitinii tlu- fiiiij,'ii.s hail .>nl\ 
been olmervcil on living Ixecli und fclleil wood. 



462 



BASIDIOMYCETES. 



scales arranged regularly in concentric lines. The stools break 
out from living stems through cracks in the bark or from wounds, 

e.g. those made by wood-peckers. 

The fir- wood, normally white, assumes, 
when diseased, a yellow or honey-colour, 
more or less like the sporophore, while 
here and there, parts may become light 
brown. The hyphae grow in all direc- 
tions, but especially as white strands up 
and down the year-rings, while others 
in horizontal and vertical direction break 
up the wood into irregular patches 
(Fig. 290). In the final stages of 
destruction the wood will be found 
laminated into its separate year-rings 
and very much broken up into irregular 
pieces (Fig. 291). 

The sporophores of this Agaricus are 
not uncommon protruding from bark- 
cankers caused by Accidium clntinam, 
and its mycelium assists in the destruc- 
tion of the stem. 




Fig. 292. — Agaricus adiposus 
and Polyporus Hartigii. Destruc- 
tion of Fir- wood. The boundary 
of the regions affected by the 
two fungi is formed by a very 
dark line of demarkation. To 
the right the destruction is that 
produced by Poiyporov.s Hartigii, 
to the left by Agaricus adiposun. 
(v. Tubeuf phot.) 



Agaricus (Pholiota) squarrosus (Mull.). On 
living and dead stems of broad-leaved tree.i. 
(Britain.) 

Ag. (Ph.) destruens (Brond.). On living 
and dead stems of poplar. (Britain.) 
Ag. (Ph.) aurivellus (Batscli.). On living and dead stems of broad-leaved 
ti^ees. (Britain.) 



" FUNGI IMPEEFECTI." 

The fungi placed here have life-histories which as yet have 
not been completely investigated, most of them being known 
only in the form of pycnidia or conidia. The number of species 
was at one time much larger, but it is gradually being re- 
duced as the forms are proved to be stages in the life 
of some species of definite systematic position in the other 
groups already considered. 

The group may be divided into the provisional sub-groups, 
the S-phaeroi^sideae, Melanconieae, and Hyphomycetes. 



FUNGI IMPERFECTI. 4C3 

I. SPHAEROPSIl>EAE. 

Conidia abjointed from conidiophores contained in darl- 
colovrcd pycnidia somewhat spherical in form. The various 
species are provisionally arranged in genera according to the 
colour of the conidia and the number of cells contained in 
them. The families here included are the Sphacrioidcae, Ncc- 
irioidcac, Leptostromaccac, and Excipulaceae. 

I FAM. SPHAERIOIDEAE. 
Hyalosporak. 

Phyllosticta. 

Fungi with colourless spores, and i)roducing sharply detined 
spots on living leaves. They occur on all kinds of woody plants, 
but as a rule the injury caused is too slight to be called a disease. 

From the long list given by Saccardo (Vols, iii., ix., and x.) 
the following have been selected : 

Phyllosticta persicae Sacc. This produces on leaves of peach 
brownisli-yullow spuis, frequently marked Ijy concentric zones. 
The name " shot-hole fungus " has sometimes been applied to 
this and other allied forms, because the leaves become more or 
less perforated by the withered spots falling out. The pycnidia 
on reaching maturity rupture the lower epidermis of the leaf 
in a star-like manner. lUiosi and Cavara do not regard this 
parasite as very harmful, because leaves attacked by it remain 
alive without serious prejudice to their function. 

Ph. pirina Sacc. has been observed injurious to pear-trees at 
( ieisciihriiii (( irrmany). 

Ph. prunicola Sacc. is the cause of spotting of leaves of 
apple, plum, cherry, and apricot. (I'.S. America.)^ 

Ph, cytisi Desm. ()u leaves of Ci/fisiis Lahuriunn in 
Britain ami Europe. 

Ph. acericola Cook et Ellis. On various species of 
niapli' (Acir i/nsi/an-jiio/i, etc.). It is descj'ilied by (!allo\vay- 

' 'I'liu cliiff iuitlinritics for tlie <tcciirii'iice of tin- "Flint;! iniiK-rfui'ti " in 
Britain uiul Noitii Aiutiica iiio Miis.see (//ciVm/i Fiiii'iiit Fluni, lsy.">), Karlow 
an<l Seyiiioiir {IIomI-IikIi .r for i'.S. Ann rim, IS'.II), ami .Saccarilo (Si/llmjt 
/uui/orujn). I'rofeHsor .). \V. 11. Trail kimlly revistil tin- reconU for Hritain. 
(Edit.) 

■-(Jalloway. '• Kt-jMirt of Ht-ct. of Vv^vl. I'atlioloj^y for ISSS." [/.S.A. I>'i>t. 
of Aijriniltun , \\'a«liington. 



464 FUNGI IMPERFECTI. 

as injurious, especially in nurseries and groves where the trees 
are grown in number. 

Ph. sphaeropsoidea E. et E. is another American species 
which has become prominent on account of its ravages in 
nurseries of horse-chestnut. The disease appears about the end 
of June, and by August the foliage of attacked trees is almost 
entirely dead. 

Ph. grossulariae Sacc. On leaves of Rihes G'rossidana in Italy and North 
America. 

Ph. vulgaris Desni. A common species on leaves of species of Lonicera. 
(Britain and U.S. America.) 

Ph. sambuci Desm. On species of Samlmcus. (Britain.) 

Ph. cornicola (D.C.). On leaves of species of Coriuis in America. 

Ph. limbalis Pers. On oblong white spots on leaves of box. (Britain.) 

Ph. tiliae Sacc. et Speg. On leaves of Tilia. (Britain.) 

Ph. maculiformis Sacc. is probably a stage of Sphaerella maculiformis 
Auersw. It is a dangerous parasite causing a leaf-spot on sweet chestnut 
{Castanea) and other trees. 

Ph. violae Desm. A source of considerable damage to violets in America ; 
it also occurs in Europe and Britain. 

Ph. althaeina Sacc. has been reported as dangerous to hollyhock in the 
United States.^ 

Ph. phaseolina Sacc. appears occasionally as a parasite on leaves of 
kidney beans. (U.S. America.) 

Ph. viciae (Lib.). On Vicia sepium. (Britain.) 

Ph. cirsii Desm. On leaves of Cirsium. (Britain.) 

Ph. apii Hals.i produces a leaf -spot on celery, and has caused con- 
siderable loss in America. 

Ph. tabaci Pass, occurs on leaves of tobacco in Italy. 

Ph. bataticola Ell. et Mart., and others, have been recorded on sweet 
potato in America. 

Ph. betae Oud. occurs on leaves of sugar beet and mangel. 

Ph. tabifica Prill- Prillieux believes the disease of beet- 
root known as " heart-rot," to be due to this Phyllosticta. It is 
probably a conidial form of Sijhaerclla tabifica Prill. The symp- 
toms of disease are withering of the outer leaves, followed by 
the appearance of whitish spots with withered tissue filled up 
with mycelium. Thence the disease spreads into the younger 
parts and causes " heart-rot " of the root. 

Frank is of opinion that " heart-rot " is caused by Sjxirides- 

^ X. J. Agric. Exptr. Station Report, 1891. 

-Prillieux et Delacroix, Bullet, de la soc. mycol. de France, vii., 1891. 



PHYLLOSTICTA. 465 

mium imtrcfacicns Fuck. This is probably the cj^use of the 
gradual blackening of the leaves, yet it does ni»t appear to 
lose its saprophytic nature. 

Frank also gives Flioma hdar Fr. as one cau.se of tlie heart- 
rot of the sugar beet (conip. Flioma). 

It will thus be seen that the cause of the rotting of beet- 
root, sugar beet, and mangold is still very obscure.^ 

Ph. galeopsidis Sacc. On leaves of d'a/eopsis Tetraltit. (Britain.) 
Ph. atriplicis ])f.-;iii. On leaves of Chenopodiuni ami Atriple.r in Europe 
and Ijiitaiii. 

Ph. chenopodii Sacc. has been found injurious to spinacii in America. 
Ph. podophylli (Curtis). In leaves of Podophyllum peltutum in America. 
Ph. primulicola Desni. On withering leaves of PriJimla. (Britain.) 
Ph. ruscicola l)ur. et Mont. On leaves of species of Rhschh. (Britain.) 

Depazea. 

A provisional genus including species of which the spores 
or conidia are unknown, so that the forms included in it will 
probably l)e found to be related to various groups. They live 
in many cases on living leaves, causing discoloration. Some 
of them are : 

Depazea acetosae Op. On Ramex Acetosa. 

D. impatientis Kinliu. On Impatiens Noli-tangere. 

D. geicola (Fries). On Gettm urbanum. 

Phoma. 

Conidia unicellular and cohmrless. Pycnidia black and em- 
bedded, Itut iiaving a distinct pore. The species produce spots 
with ill-di'tiiK'd margins. 

Phoma abietina llaiLig- {Fn-iifnnin/t Klnitiniiin I'rill. ct 
Dclac). This {tarasite is a fri;([U('nt cause of ilcath tn thf 
.silver lir. The In'anclies liecome brown, yet retain their needles, 
hence when they occur i-solated amongst neighbouring green 
liranches tiiey are at once conspicuous. On close e.Niimination 
of the di-ad or dying br;nich('s, areas nf sliruidv or con- 

' AcLonliii^,' tu KarUon (I'ltroirxk. Akad. /. Lauduirthsi-hajl, iNiMl) uikI H»ll 
riegel (Z'itsr/i. ili m Vinin f. J{iihfnzurk'>'rtniliiMtri>' d. drulsch. litirheH, 181K)) 
iiim,'c-t.s take no part in it. 

'-l^a^ti^,', L' hrliiirli d. Iinn)idraid/uit> ii, K<1. II. (Kiij.;li.Mli Kilitiun hy W. 
SoiiuTvillt;). Mcr, K. , Junrufd ilf /i(if'iiii({w, \H'X\. 

'2('. 



466 



FUNGI IMPERFECTI. 



stricted tissue will be found extending quite round the twig 
(Fig. 293), At these places the bark and cambium have been 

killed, whereas the higher 
portions of the twig have 
continued to increase in 
thickness. Numerous 

small black pycnidia 
break out on the bark 
of diseased places and 
give off small unicellular 
spindle-shaped conidia, 
which convey infection 
to new hosts in August 
or September. Killed 
branches die and dry 
up without casting their 
needles.^ 

Ph. pithya Sacc. 
causes a disease similar 
to the preceding on the 
Douglas fir {Pscudotsuga 
Douglasii). The pycnidia 
of the fungus are found 
on dead constricted parts 
of twigs, and they, as well 
as other symptoms of the 
disease, closely resemble 
those of Phoma ahietina. 
Eostrup^ defined and de- 
scribed it as Ph. ^;iYA?/a 
Sacc. Magnus also re- 
cords it on branches of 
Pinus sylvcstris in Berlin 
botanic garden. 
Other species of Phoma frequent other conifers and broad- 




Fio. 203.— P/io/iict oJjuAiHiK Twig of Silver Fir show- 
ing the constriction charactei-istic of this disease, 
dotted over with pycnidia. (After R. Hartig.) 



/ ^ Bohm {Zeitsch. f. Forst- u. Jagd-wesen, 1896, p. 154) describes and figures 
an attack of this parasite on Pseudotsuga Douglasii in North Germany. One 
cannot, liowever, avoid suggesting some confusion between this and Ph. pithya 
described next. (Edit.) 

-E. Rostrup Undersocqdser over SnyJtes vampes Angreb paa Skoiiraeer, 
188.3-1888. 



I'HUMA. 



46( 



leaved trees, but details in regard to their parasitism are 
wanting. 

Ph. Hennebergii Kiihn.^ lirown-spot of wheat-ear.s. This 
produces, on ilit' ulunies of wheat, brown spots with projecting 
pycnidia from which unicellular C(midia emerge. The grains of 
attacked ears shrivel up and become spotted, while the value 
of the chaff as fodder is much diminished. Whole fields may 
be attacked, showing marked discoloration, and j)r(njncing Itut 
few healthy ears." The fungus may also 
appear on the leaves and produce pycnidia. 

Ph lophiostomoides Sacc.^ Lopriore 
regards this as a parasite on cereals, but 
Cavara looks on it as saprophytic on the 
dead ])lants. 

Ph. ampelinum De Bary (Sphaceloma 
(iiiipeliniiiii i)i' i'>aryj. Anthracnose of the 
Vine.* The mycelium of this fungus can 
penetrate into leaves, green bark, or fruit, 
and kills the tissues. Spots are first pro- 
duced, then enlargement (jf the neighbour- 
ing tissues takes place, causing the spots 
to appear as if sunk in depressions, and 
reminding one of hail- wounds. On leaves 
and grapes, tlie spots are sharply defined, 
at first dark-l»rown, later with greyish 
centres and dark-Virown margins. In the 
later stages the dried-up spots may drop out of the leaves. 

Anthracnose, or " birds-eye rot," constitutes one of the dreaded 
vine diseases of America and Europe, so tliat it has received 
much attention, both as to its life-history and remedial measures ; 
as yet however with but partial success. Copper sulphate 
solutions seem to be fairly succes.sful remedies, as shown from 
results of the many experiments recorded in llie .Journal of 

' Kiihii, J/tdirii/id, 1.S77, J). 1'21 ; also in Kiilienliorst'.s /'»;/;/«< /(/•<)/). N<>. •J-Jlil. 
Friiiik, Ziittih. Jar l'il<iiitfiikrankli>iltn, ill., iS'.t.S, p. "JS. 

- Krik.sson (Mllthl. (l< r k. Landh. Aknd. Stdcklioliii, ISOO) ri-conla a citso <tf 
thiH kind, Imt tlie coiiidia lire (Iniwii two-celh-W ii.s in a /)iji/otliiin, wliert'iiH 
Kiilm's r)!i^inal ilrawiiig.s have only onecolleil conidia. 

•""Cavara et KriksHon, Zt.it.ic/i. /. I'jl(in-,i ukrunkhiiliu, in,, |». 'l'.\. 

*<ir)etlie, Mitlhl. uh. ilm. sr/iiinrzi n lininnrd. /{then. l.,ei|i/i),', IS7J<. * oriiu, 
Ihd/</. d< In Sor. holan. (U Fmun , 1H7«. rrillieux (ithm), 1H7!». Uatliay, " t>rr 
JU'irkrof," IS'.H. Scriltner, /tijiort »/ I'.S. Anm: /)r/,r. t,j Aiirindlurr, IS.SO. 



Fig. 2!I4. — /'Aoi.iu uiiiikU- 
inuii. IJrown conoave spots 
on shoot and berry of Viii». 
(V. Tuljciif del.) 



468 FUNGI IMPERFECTI. 

Mycology and the bulletins and reports of the American experi- 
mental stations. (Compare also (Uoeoaporium ampelophagiim 
(Pass.) p. 484.) 

Ph. betae Frank. ^ The younger leaves of well-developed 
beet-root become black, and the disease extends into the root. 
Mycelium fills the diseased parts and penetrates into healthy 
tissues. Pycnidia are developed on the diseased spots. The 
fungus is no relation of Sporidesmium p)ui''efaciens, a form to 
which a root-rot is ascribed by Frank. It is however proljably 
identical with Prillieux's Plujllosticta tahifica. Kriiger found 
the disease so common, that in many localities as many as 80 per 
cent, of the plants were destroyed. Sorauer regards the root-rot 
of beet to be sometimes caused by Phoma, sometimes by 
Sporidesmium, perhaps in some cases by both together. 

Ph. sanguinolenta llostr.- attacks carrot plants in their first 
year, causing greyish-l»rown depressed spots on the bulbs with- 
out however appearing to be very injurious to them. When 
the seedlings are planted out in spring, the mycelium 
extends into the stem and causes the umbel to wither at 
flowering so that no seed is formed. Pycnidia are developed 
from all attacked spots and give off conidia as red tendril-like 
bodies — hence the species-name. Certain varieties of carrot 
appear to resist attack by this parasite better than others. 

Ph. solani Hals. This causes damage to the egg-plant 
(Sola/ium m.dongcna).^ Young plants die off on the hot-beds, 
their stems dying near the earth and shrivelling up. The 
pycnidia of this Phoma appear on the killed parts. 

Ph. cydoniae Sacc. has been reported as injurious to quince 
trees. (U.S. America.) 

Many species cause leaf-spot diseases. Some of the more 
important British and American species are : 

Ph. pinastrella Sacc. On Finns si/lvestris and others. (Britain.) 

Ph. strobi (13. et Br.). On Pinus Strohus. (Britain.) 

Ph. taxi (Berk.). On yew. (Britain.) 

Ph. Candollei (Berk, et Br.). On box. (Britain and U.S. America.) 

Ph. sorbi (Lasch.). On leaves of Pyras Aucuparia. (Britain.) 

1 Frank, Zeitsch. /. FJlanzenkrankheiten, iii., p. 90, aiul Deutsche landw. Pr. 
No. 89, 1893. Kriiger, Zeitucli. f. PJlanzenkrunlcheiten, iv., 1894, p. 195. 

-Described and figured by Halsted in Bulletin 91, N. J. Agric. Exper. 
Station. 1892. 



I'HOMA. 469 

Ph. malvacearum West. On mallows aiid hollvliock in Enrnpe. 

Ph. longissima (IVrs.). In species iif Unibelliferae and ("lienupo«liaceae 
in Eiiidjje and Anieiit-a. 

Ph. errabunda De.-^ui. In steni.s of Virbascum. (iJiitain.) 

Ph. cucurbitacearum (Fr.). < )n fruits of various species of Cunir- 
bitaoeae in Europe ami America. 

Dendrophoma. 

Pycnidia similar to Plumxa, conidiophores however bearing 
several ciiiiilia citlin- (ui Uranches or little processes 

Dendrophoma Marconii ( av. attacks Hemp {Cannabis sativa), 
causing dark oblong spots on the green stem. Tlic pycnidia 
are embedded and Ineak through the epidermis with a round 
pore. The conidioj)hores are branched, with swollen ends 
carrying little short rod-like unicellular conidia. In ca.sc of 
attack, which generally occurs towards the close of the 
vegetative period of the hemp, it is suggested to cut the 
crop somewhat prematurely, and thereby prevent maturing and 
spreading of the fungus. 

D. convallariae Cav. proihices dark elonf^ated spots on leaves of <'oii- 
vallarifi m (ijalis, 

D. valsispora Pen/., is recorded by Penzi;Lf on living' leaves of Cifrifs 
Limoiiniii (Lemon). 

Sphaeronaema. 

I'ycnidia embedded, mendtranous, and long-lieaked. C'onitlia 
ovoid or oblong, unicellular, and almost colourless. 

Sphaeronaema fimbriatum [V\\. et Hals.), {C< rafon/stis 
jLiiihiidiii VA\. cL JlaLs.). Jjlack lot or black shank of sweet 
potato.' The parasite .shows itself as black depressed spots on 
the lower parts of young plants, and these may extend over 
the whole .shoot. The disease is best recognised on the tubers, 
wlnrc it consists of dark, somewhat greenish spots, varying 
fi(jm ] to 4 inches in iliameter, and extending some distance 
int(j the tissue. These sjiots when once seen cannot be mis- 
taken, as they are sunk areas with distinct margins, like sjiuts 
burned into the potato with a pieci' of metal which has left 
the skin uninjured. 'i'lie jnycelium eonsi.sts of thick-walled 
olive-brown liyphae, uliidi cause death and dest nn t ion in the 

' Ulilstcd iili.l l-'iiiirliij.i, Ji.nr. i./.Ui/r,,/,.,!;/, \'..|. \tl., IMH. with l''i^;ill .m. 



470 FUNGI IMPERFECTI. 

cells of attacked tissues. There are three modes of spore pro- 
duction : (1) brown macro-conidia inside the tissues; (2) colour- 
less micro-conidia on the spots; (o) spherical pycnidia with long- 
necks ending in a fringed opening. A sclerotial form is also 
strongly suspected. Remedial measures recommended are, de- 
struction of all diseased parts, change of crop on diseased fields, 
and selection of healthy seed and strong sprouts. 

Several other species of this genus are recorded from North 
America, but details in regard to their mode of life are 
wanting. 

Asteroma. 

Fungi forming star-like, dark-grey, mycelial patches on the 
surface of plants. Pycnidia very small and containing tiny 
ovoid or short cylindrical spores. Several species frequent 
living leaves.^ 

Asteroma impressum Fuck. On Tussilago farfara. 
A. prunellae Part. On leaves of Prunella vulgaris. (Britain.) 
A. ulmi Klotscli. (Britain), and A. maculare End. On Ulmvs. 
A. padi (D.C.) causes a leaf-fall on I'runus Padus. (Britain.) 
A. geographicum Desm. is found on the leaves of species of Crataegus. 
Primus, and Pyrus in Europe and America. 



Pyrenochaeta. 

Pycnidia emergent or sessile, beset with bristles. Conidia 
oblong, on Ijranched conidiophores. 

Pyrenochaeta rubi-idaei Cav. forms black spots on leaves 
of Rubus Idaeus. The pycnidia are spherical with a tuft of 
bristles projecting from their terminal pore. The conidia are 
little, oval, and with one or two cells ; they are produced from 
slightly branched conidiophores. 

Vermicularia. 

Conidia unicellular, rarely bicellular, generally spindle-shaped ; 
they are produced inside pycnidia, and are embedded amongst 
brown septate hairs. The species are a frequent cause of leaf- 
spot, but most of them have not yet been sufficient!} investigated. 

^ Cicinohulus Cesafii De Bary, allied to this genus, is a parasite on Oidium 
7'tickeri, the dreaded vine-parasite. 



VERMICULARIA. 471 

Vermicularia trichella Fr. otriirs on liviiiLC leaves of ivy aiul (jtlier plants. 
(Britain.) 

V. ipomoearum Scliw. On .species of Ipomoea in America. 

V. microchaeta Pasc. On living leaves of Cninellia japouica in Italy. 

V. circinans licrk. Onion rot in I]ritain ami U.S. America. 

Placosphaeria aiul Cytospora are genera cuiitainiiig forin.s 
para.siiic uii liviug plants, but of little practical importance. 



Phaku.sporae. 

Coniothyrium. 

Pycnidia brown ur l)lack. Conidia lirown, unicellular, .spheroid 
or ovoid, and borne <in .short eonidiophores. 

Coniothyrium (Phoma) diplodiella Sacc.^ A\'iiite-rot of the 
vine. I'his di.sease has a wide distribution in Hungary, and ha."? 
also been observed in France, Italy, and America. It has caused 
considerable damage, especially in Northern Italy, where it was 
for a long time regarded as the black-rot. 

According to Mezey, this parasite is distinguished from 
Lacstadia (black-rot) in the following points : — The pycnidia 
and conidia are larger; the mature pycnidia are greyisii or 
light brown (never black), the mature conitlia are brownisli. 
Tlie disease attacks the fruit only, causing it lu fall off. IJathay, 
however, states that it also attacks young shoots, infection taking 
place from the fruit. Diseased grapes become soft, rotten, and 
wrinkled ; the ridges are beset with pycnidial pustules, as in 
black-rot, but the grapes never become luittle and hard. 

Viala and IJavaz^ have recently succeeded in rearing perithecia 
from twigs and fruit-stalks set in sterilized moist sand. None 
could be found on grape-s. The perithecia are globular, enclosed 
in a l)lack covering several cells thick, and with a large crater- 
like aperture. The asci and para))hyses arise only from the tlt'))lh 
of the perithecium, the latter being longer than the former and 
fretjuently branched. Tin; asci are elul)-shaped ami shorl-stalki'ii, 
and contain eight spindle-sha[)ed colourless or yellowish asco- 
spores, divided Ijy onct to three cross-septa. They germinate and 
j)roduce one oi' more gi'lin-tubes. 

' Kiithiiy, "Der White- Kut." Dii IC, ,W«(,/,,'. \H\r2. 

(jeneral dcsc-riplion in /u/ioif !), .V» ic Yorl: A'lrir. Erp>r. S/it/iuii, IS'.M). 
'-"Vialii imtl Kiiva/., <'<,iiij>/. nwl., i \i\., l.S'.tl, p. WW. 



472 FUNGI IMPERFECT!. 

A new genus Gharrinia, belonging to the Sphaeriaceae of the 
Ascomycetes, has been formed to receive this species. 

Sphaeropsis. 

Pycnidia black and spherical, with an aperture. Conidia ovoid 
or oblong, unicellular, dark-coloured, and on stalk-like conidio- 
phores. 

Sph. malorum Peck. The cause of a disease in America, 
known as the black-rot of apple and quince. The mycelium 
permeates and destroys the skin of the fruit, which, in con- 
sequence, becomes dried up and munnnified. It also occurs in 
Britain. 

Other species attack plants of various Kosaceae. 

Phaeodidymae. 

Diplodia. 

Pycnidia, small, spherical, and dark-coloured : the conidia are 
two-celled when mature. 

Diplodia gongrogena Temme.^ Temme discovered a mycelium 
and the pycnidia of this Diplodia in aspen {Poindus tremulae) 
exhibiting hypertrophied outgrowths of wood and riud. As yet 
it has not been possible to artificially produce these malformations 
on the aspen, nor other somewhat similar ones which occur on 
the willow. 

Other species of this genus attack many trees, e.g. holly, lilac, 
horse-chestnut, mulberry, and various conifers. 

Hyalodidymae. 

Ascochyta. 

Conidia ovoid or oblong, bicellular, and hyaline. The pycnidia 
have a central aperture, and are embedded in discoloured portions 
of leaves or twigs. 

The following species are of practical importance : 
Ascochyta pisi Lib. (Britain). Briosi and Cavara state that 

'Temme, Land/cirlh. Jahrhuch, 1887. 
Thomas, Verhand. d. hofan. Verein d. Prov. Brnndenhiirg, 1874. 



ASCOCHYTA. 



473 





this fungus is injurious to Fisuin mticurn, Fhasroh's rii/;/riris, 
Vicia sativa,eXc. It causes spots on leaves and ])()ds, fnllcjwed l)y 
(Iryinci up of the former and deformation uf the kilter. The 
p}'cnitlia appear as tiny ])oints on the spots, and y;ive out hicellular 
cyhmhical conidia. 

As. Boltshauseri Sacc.^ 
This species was tirst observed 
in Switzerland on bean {Fha- 
seolus vulgaris). Leaves of all 
ages become brown -spotted, 
and premature defoliation may 
follow. The spots are marked 
by concentric zones, and bear 
pycnidia. The conidia are 
two- to three-celled, being 
distinguislied in this and by 
their larger size from the 
preceding species. 

The following species fre- 
quent living leaves : 

Ascochyta tremulae Tliiini. On 
tlie iisjieii. 

A. metulispora, B. tt IJr. (Jii 

A. armoraciae Fuck. < )i) 
(Ilritiiiii.) 

A. periclymeni Tliiiiu. (Jii Lniiti-ent I'l ridiiini-iiuui. 

A. maculans Fuck. On JlecWa Ildix. 

A. Ellisii riiiiiu. On Vitis La1>ruHca in Anierira. 

A. brassicae Thiiui. ( )m /J/-a.tsiiii uleracea. 

A. dianthi (A. 8.). On Diant/mx. (Britain.) 

A. pallor l!erk. On Rubus hhiens. (Britain.) 

A. viciae 'I'lail. On Vicin sepinm, etc. (Biitain.) 

A. malvicola Sacc. On Mah'a sijlreatris. (Britain.) 

A. graminicola Saic. ( )ii variuus j,'ra.ssfs. (liritain.) 

A. scabiosae Ilalili. < »ii Knautia urcensis. 

A. nicotianae l',i^>. ( )n Xicotiunn Tahncrum. 

A. digitalis I'lK-k. On Diijltuhn piir/nirfn. 

A. fragariae Sacc. has hccn found injuri<ius ti> tlic stra\vl)crrv ticp in tin- 
rnitfd .Stat.s. 

A. aspidistrae ^'ivin {(i<trdtner's C'/ironir/,\ xvii., IM>.'t) a.s a parasite on 
.[.■<iiiilixtrii \\\ liritain. 



Fig. 29£.— .-(^'o-/', ./f.< /,..<, on IVii. KularK'fd 
suction of pycnidia, und still more enlarged 
conidia. (v. Tubeuf del.) 



eavcs uf the a.sli in Scotland. 
Armoracia rustieana (Horse-iatli.sli). 



' HoIIhIiuumc T .\liirissv«il, Z'ilxrlnill /. /'fliur.ndnniUi' !'• n. I., p. I .■{."> 



474 FUNGI IMPERFECTI. 

Actinonema, 

Pycnidia small and situated uii a gossamer net of mycelium. 
Conidia hyaline and divided by one or more cross-septa. 

Actinonema rosae Lib. {Asteroma radiosmn Fr.). This pro- 
duces black radiating spots on rose-leaves, on which pycnidia 
with bicellular conidia are developed. A premature defoliation 
takes place, which in turn causes the upper buds to unfold in 
autumn before their time. The mycelium is distributed both 
inside the leaves and superficially. Timely removal of diseased 
leaves and defoliated shoots might be recommended as remedial 
measures. 

A. tiliae Allesch. shows itself in spotting of the leaves and 
petioles of lime, and may bring about defoliation of the whole tree. 

A. fagicola Allesch. produces white spots with dark margins 
on living beech leaves, and causes gradual discoloration of the 
whole leaf. According to Allescher,^ this disease brings about 
premature defoliation of beech. As yet it has been observed only 
in Upper Bavaria. 

A. fraxini Allesch. On living leaves of the ash. 

A. crataegi Pers. attacks leaves of Pyrus Aria, P. torminalis, and 
Viburnum Opnlus. 

A. podagrariae Allesch. On living leaves of Aegopodimn Podagraria., 
and Chaerophylliini hirsutnm. 

Darluca. 

Darluca genistalis (Fr.). On living leaves of Cytisus sagittalis. This may, 
however, be only a parasite on Uromyces cytisi with which it is frequently 
observed, just as Dar. filum occurs on several Uredineae. 

Diplodina. 

Similar to Diplodia, but having colourless conidia. 
D. castaneae Prill, et Delac." produces canker-spots on the 
stems of chestnut, and brings about death. 

PlIR.VGMOSrORAE. 

Hendersonia. 

Pycnidia formed under the host-epidermis, which is later 
ruptured. Conidia brown, two- or more-celled. 

^ Allescher, Iledivigia, 1894. 

'^ Prillieux et Delacroix, Bull. toe. mycoL de France, 1893. 



HKNDERSOMA. 475 

Hendersonia foliicola (]5erk.) (Ikitain ami Europe). The 
black ;^lul»ular p\(iiitlia are produced superHcially on leaves of 
Juniperus communis. The couidia are elliptical in shape, three- to 
five-celled, and abjointed from filamentous conidiophores. (This 
species is not identical with Pod iosoina Junipcri /3 minor Corda, 
which is more like the needle-frequenting form of Gi/muo- 
sporciiKjium juniperinum.y 

Spvernl species are found on livin^f leaves : 
H. cydoniae C et Ell. oii quince in America. 
H. mail Tliiini, on apple. 

H. rhododendri Tliiim, on li/tododendrou hirsutuiii in Northern Italy and 
Germany. 

Cryptostictis. 

Similar to Hendersonia, but having ciliate spores. 
Or. cynosbati (Fuck.). Sorauer" regards this as parasitic 
on Horn ronina, and causing death of portions of the rind. 

Stagonospora, Couturea, Asteromidium, and Camarosporium contain 
species said to frequent livin;^ leaves of various plants. 

SCOLECOSPORAE. 

Septoria. 

Spores generally multicellular and hyaline ; produced from 
short conidiophores, contained in lens-shaped embedded pycnidia. 

Septoria parasitica Ilartig.^ This disease may be frequently 
ob.sfr\L'd in vcjung plantations and seed-beds of Spruce. The 
symptoms are very like those following damage by frost, brown 
needles appearing in May towards the base or middle parts ot 
young shoots, and followed by a premature needle-cast. The 
disease is most a])i)arent on lateral shoots, which become sharply 
bent d(jwnwards, the green needles hanging liiiii>ly till llu\ 
wither and fall as the whole shoot shrivels up. 

'i'he i»ycnidia are little, black, and sjjhcrical : tlu-y are pro- 
duced during the sumnicr, parlicularly tnwaids ilic lnwci- end 

' K. V. 'riil>euf, " (;fiieratii>n.'*-wecli«el ( iyimiii.sp<>riiiij;iiiiii-.\rti-ii," Cutfra/ltl. f. 
liaktu-idldijii- II. J'tiranitfiiL'iniilr, 18!H. 

- llaiidliiirh il. /'JIaiiztiikraiil:hf iti ii, II., 187(5, p. .'ISS. 

^K. HartiK, Ziilsrh. f. Forsl. n. Ja'/itirtnni, 181K) ; ui'l l'ur>t/l,h nittiinri.^s. 
ZeitHfhrift, 1893. 



476 



FUNGI IMPERFECTI. 



of the shoots, and either rupture the epiderinis or grow out from 
the leaf-scar cushions (Fig. 297). The conidia are abjointed 
from filamentous conidiophores inside the pycnidia, and emerge 
as tendril-like structures. They are two-celled, small, cylindrical, 

and pointed at both ends. 
Germination takes place 
easily in water, and the 
disease spreads rapidly over 
the young developing shoots 
during May. The mycelium 
permeates the twig, living 
both inside the cells and 
between them. 

The disease has been 
observed on Pieea exaisa 
and P. Mcnziesii, not only 
in nurseries and on young 
trees, but also in pole- 
forest, where it frequents 
the upper crown and causes 
death. At the beginning 
of an attack the pruning 
of diseased twigs in young 
plantations should be at- 
tended to. 

Septoria rubi (Westend.).^ Blackberry leaf-spot. This is a 
parasite of some economic importance in the United States, where 
it interferes with the blackberry culture. It also occurs in Europe 
and Britain. 

S. ribis Desm. produces a somewhat similar disease on leaves 
of currant and gooseberry.^ (Britain and US. America.) 

S. piricola Desm. occurs throughout all Europe, causing little greyish 
spots on leaves of pear trees. It is probably a pycnidial form of Splwcrella 
IvciUae Sacc. 

S. crataegi Kich. A common sjiecies on leaves of Crafaegia in Euro])e. 

S. cerasina Peck. On leaves of Prunus serotina in tlie United States. 

]\Iany forms of Septoria infest cultivated vegetables : 

S. petroselini Desm. is the cause of dry spots appearing on leaves of 




Fig. 296. — Sfplnria parasiticd. a. Young diseased 
shout of Spruce, with apex still fresh and green. 
h, Needle diseased towards base. <; Apex of a two- 
year-old shoot, into which the disease has extended 
backwards from the .younger shoot ; the brown 
discoloration of cortex and pith is indicated by 
shading. (After R. Hartig.) 



^Description in Bulletin, No. fi, Ohio Ai/ric. Exper. Station, 1891. 
-Description in Bulletin, No. LS, Iowa Agrir. Exptr. Station, 1891. 



SEPTORIA. 



477 



cultivated jjarslev in Europe ami 
enemy of tflt-iv in tlie United St; 

S. armoraciae Sacc. On 
horse-radish in America. 

S. consimilis Ell. et Mart, 
frequents lettuce in America. 

S. lycopersici Speg. This 
para.site, originally observed in 
America, has recently been de- 
scribed by Briosi and Cavara on 
tomatoes in Italy. It causes 
spots on leaves, stems, and 
fruits, inflicting thereby con- 
siilerable loss on cultivators. 

The following are im- 
portant tbrni.s on otlier 
cultivated plants : 

S. graminum iJesm. 
causes light spots on leaves 
of wheat, oats, and grasses. 
It has been observed to 
injure the cereal crop in 
Italy.^ It is recorded for 
Uritain and U.S. America. 

S. cannabis (Lasch.). 
This on leaves of hemp pro- 
duces spots, which are at 
first whitish, then yellowish 
with dark margins. The 
pycnidia are embedded in 
the upper side of the leaf. 

The following species 
have caused injury to 
garden plants : 

S. dianthi Desm. Car- 
naLiou-.spoi. Tiie disease 
appears on tlie leaves and 
stems as rounded spots of 



iiritain. A variety {apii Br. et C'av.) is an 
•ites. 




Kio. 297. — ri, Leudur-oboot uf .Spnico, purtlally 
killed and defoliutc*!. />, Pycnldiu L-niuiv>i>K' froiii 
till! rind mid llif Iciif-jtcurs { x 6). c, Kuniiiktioii 
i)f ciinidiii Inside !i iiycnidiiini ( x '.'10). (/, Si«iroN 
KLTinlniitin^' In water. < , S|Hireii K'-'nalniitin); in 
nutritive gelatine, (.\fter K. Ilartig.) 



' Cuvara (^»:i/Wt. /. Pjlami nkrankluili n, in., p. 'J3) regards tliis ami .S*. tritici 
with its variftie.s, as forms of a single species ; also Kriksaon (Om ^'liijrii 
HJukilomur a oiUwle I'uzter, 1890). 

- AtkiiiBoii, " ( 'iiriiation DiHcases," at Anierican C.uu.ii i.m ."^cx iiiv, Is't.H 



478 FUNGI IMPERFECTI. 

dirty white or brownish colour with a darker margin. The 
pycnidia appear as black points on the spots, and ruj^ture the 
epidermis before giving off their septate spores. 

S. anemones Desm. On Aiwmo7ie. (Britain.) 

S. lychnidis Desm. On Lychnis diurna. (Britain.) 

S. epilobii West. On Epilobium. (Britain.) 

S. stachydis D. et R. On Stachys. (Britain.) 

S. urticae D. et E. On Urtica dioica. (Britain.) 

S. cyclaminis Dur. et Mont. This produces roundish spots with 
concentric markings on the leaves of Cyclamen which then gradually 
wither. 

S. chrysanthemi Cav. causes a leaf- spot on Chrysanthemum japonicum and 
G. indicum. 

S. exotica Speg. attacks cultivated New Zealand species of Veronica. 

S. hydrangeae Bizz. causes injury to cultivated Hydrangea. 

S. sedi West, injures Sedum under cultivation in the United States 
and Britain. 

Other species on many other herbs in Britain and America. 

Many species of SeiJtoria have been recorded on trees and 
shrubs, e.g. : 

S. rosae Desra. On roses. (Britain.) 

S. hederae West. On ivy. (Britain.) 

S. fraxini Desm. On the ash. (Britain.) 

S. nigro-maculans Thum. On green walnuts, stunting their growth. 

S. castaneae Lev. On the sweet chestnut. 

S. aesculi (Lib.). On the horse chestnut. (Britain.) 

S. pseudoplatani Rob. et Desm. On leaves of sycamore. 

S. populi Desm. On leaves of poplar. 

S. didyma Fuck. On Salix triandra and S. cdba. 

S. cornicola Desm. On leaves of CorniLS sanguinea. 



Phleospora. 

True pycnidia are not formed, but the conidia are abjointed 
from cavities in the stroma ; they are hyaline, rod- or spindle- 
shaped, and consist of two or more cells. 

Phleospora aceris (Lib.). On living leaves of Acer Pseudoplatanus. 
(Britain.) 

Phi. mori (Lev.). On living mulberry leaves ; probably related to 
SpJiaerella mori. (Britain.) 

Phi. ulmi (Fr.). On living leaves of elm. (Britain and America.) 

Phi. oxyacanthae (K. et S.). On living leaves of Crataegus Oxyacantha. 
(Britain.) 



DILOPHOSPORA. 479 

Dilophospora. 

Dilophospora graminis I)<siii. (Britain.) This attacks rve, 
wheat, and various grasses. (Jbhuig light spots are produced 
and Lear the pycnidia ; when these occur in the flower heads, 
stunting of the grain takes place. (See also DUupJiid, p. 222.) 

2. FAM. NECTROIDEAE. 

The fungi of this i'amily are chietly pycnidial forms of the 
Asconiycetes, and as such have already been considered. 

3. FAM. LEPTOSTROMACEAE. 

lIVALOSroliAE. 

Leptothyrium. 

Pycnidia black and discoid. Spores ovoid or spindle-shaped, 
unicellular, and hyaline. 

Leptothyrium periclymeni ( Desm.). ( )n living leaves of 
specie.-^ of Lnuiccra. (fjiitain.j 

L. alneum (Lev.) produces roundish leaf-spots on species of 
Ainiis. (15ritain and America.) 

L. acerinum (Kunze) causes spotting (»f the leaves of Acer 
campestrr and A. 'platanokhs. (Britain.) 

Several other species occur both in Europe and America. 



Melasmia. 

The l)lack pycnidia occupy black extended stromata. Cnnidia 
siiii]tle and unicellular, Ixirne on rod-like conidiopliores. 

Melasmia berberidis Thiim. et. Wint. < )i) living leaves 
of barljcrry. iJrown spots are produced, bearing tlie pycnidia 
as black pcjints ; the spots cause total or partial death of ilie 
leaves, frequently ending in defcjlialimi of the shrubs. 

M. empetri Magn. ( I'.ritain.) This species was observed by 
Magnus ^ causing an ciudeniic disease (tn crowberry. The 
symptoms were al)nni-nial fbingaiinn (if young twigs, and ihi' 
leaves remained smaller than usual. The rind (»f the slt-m was 
found to be permeated by a mycidium which jinujuced black 

^ Birirhh '/. ilnitHch. hofan. UtHtll., 1880. Witli illu«triaioiiM. 



480 FUNGI IMPERFECTI. 

pustules bearing the pycnidia of this Melasmia. The cells of 
the cortex dried up, and the rind became detached from the wood 
in the following year. The leaves were never found attacked. 
(The species is not a Rhytisma ; nor does any species of Rhytisma 
produce similar hypertrophy of its host.) 

M. acerina, M. punctata, and M. salicina are now recognized only as 
pycnidia of the species of Rhytisma bearing these same specific names. 

Leptostroma. 

Pycnidia oblong, black, and flattened. Conidia ovoid or 
oblong, unicellular, and whitish. 

Leptostroma punctiforme Wallr. Found on the leaves of 
Salix, Rosa, Biums, EuphorMa, etc. 

L. caricinum Fr. frequents leaves of Carcx and Eo'iojjhorum 
in Europe and North America. 

The parasitism of other species is uncertain. 

Labrella and Discosia are genera whose species have not as yet pro- 
thiced diseases of any serious economic importance. 

Phragmosporae. 

Entomosporium. 

Entomosporium maculatum (U.C.) Lev} This fungus, under 
the name of leaf-blight of pear and quince, is the cause of 
considerable loss in the cultivation of these crops. Defoliation 
takes place early in the season and young seedlings are forced 
to form a new set of leaves, whereby their reserves of food are 
exhausted. If this be repeated several times the plants become 
exhausted and are killed off in winter. Stocks already budded 
seem to remain immune if not already diseased. The leaves 
are first attacked, but later the succulent growing apex of the 
twigs may also succumb. The parasite hibernates on the bark 
in small depressions containing the pycnidia ; thence it spreads 
in early spring, so that pustules appear on the young leaves 
before they are fully developed. 

Spraying with Bordeaux mixture, or solution of copper acetate 

1 Galloway and Southworth (Report for 1888 of Section of Veyetabk Pathology, 
Dept. of Agriculture, U.S. America) give a historical account of the fungus 
and a bibliography. (Edit.) 



ENTOMOSPORIUM. 461 

(G oz. in 2G galls, water) have both produced good results in 
checking the disease.^ 

E. mespili (D.C). (See Stigmatea mespiH, \>. 210.) 
Scor.KcnsruHAK. 

Brunchorstia. 

Brunchorstia destruens J^iiks.s. {Ji. jiini Allesch.). In Nor- 
way almost all the plantations of Austrian Ijlack pine {Finus 
Laricio) from five to thirty years old have become diseased and 
died out. Similar ravages have also been observed in Germanv. 
Brunchorst ascribes this to a parasitic fungus whose mycelium 
may be found in all parts of diseased twigs and needles, and 
whose pycnidia are formed on the killed remains. The disease 
begins in young first-year twigs, the mycelium growing in 
the cortex, pith, and wood. The needles are attacked in 
summer, become brown from tlie base upwards, and the 
pycnidia make their appearance under tlic scale-leaves. 

Brunchorst - describes the fungus as follows : Pycnidia par- 
tially emliedded in the tissues of the liost-plant ; the smaller 
ones being simple, the larger divided ]>y complete or partial 
partitions. The inner wall as well as the partitions of the 
pycnidium are closely beset with straight basidia, from the 
apices of which stylospores with two to five septa are abjointed. 
Paraphyses are never present. The peritiiecia are black, oljlong 
or rounded, sliglitly grooved, and 1-2 mm. in diameter: they 
dehisce by one or more irregular pores in the wall. The 
.spores are very minuic (.".0 — 40 = ."./x), tapering, and rounded 
at each end. 

Scliwarz considers Jiriimliorsfia as a conidial form of Cnuin- 
(juim ubirfis already described (p. 20 1). 

It may be here mentioned that drying-uji of pinr-twigs may 
be (hie to ht-ating by tlic sun in frosiy weather, or to frost 
itself;^ these aie, however, quite disiinel from the (Hsease just 
described. 

' Kuiicliild {Journal nf Myrolinji/, \'ul. vii.) ^'ive.n if.sult.s (if tiviitiiuiit with 
variuiiH fuiij^iuiileH on seveiiil viirieties of peiir iiml (|iiiiicu. (Kilit.) 

'-"('eher eiiie neiie Krankheit il. Sili\var/.f<iliro." ISerguiiH Miihuuiii, ISSlt. 

^ K. Hiirtig, " \'ertiockiifii u. Kifriinii tl. Kiefenizwuigc," ForstlichmttitrwiKn. 
Z'-itxrhnyy, 1m;k> uml I.S«».">. 



482 FUNGI IMPERFECTI. 

4. FAM. EXCIPULACEAE. 

The parasitic nature of the species of this family has not as 
yet been investigated to any extent. 



II. MELANCONIEAE. 

True pycnidia are not formed, but the conidia are developed 
in clusters or aggregations covered over at first by the epi- 
dermis of the host-plant, which is ultimately ruptured. 

ITyalosporae. 

Gloeosporium. 

Conidial clusters colourless or grey, never black ; they rup- 
ture the overlying epidermis and give off unicellular conidia, 
one from each conidiophore. 

Gloeosporium fructigenum Berk.-^ (Britain and U.S. America). 
Apple Rot or Ripe-rot. This is a very serious disease for 
American cultivators. It not only attacks apple, but also the 
grape, pears, peaches, and egg-plants." On the apple it appears 
first as brown spots wdiich become more conspicuous as the 
fruit enlarges. The spots on first sight look like decay, but 
they are quite firm and soon bear pustules of a white or 
pinkish colour turning to black. The attacked part of the apple 
has an intensely bitter taste, and should be carefully removed 
before eating the fruit. On grapes the fungus produces tiny 
raised pustules, which on the white varieties are situated on 
spots with a purple centre and a brown margin ; the pustules 
when mature give off flesh-coloured conidia. The grapes 
gradually shrivel up, but do not become black as in the case 
of the black-rot, nor do they assume a bitter taste as the 
apples do. 

The apple bitter-rot makes rapid progress amongst stored 
fruit, especially before it has been sorted out. Care should 
therefore be taken that diseased apples are removed as soon 
as possible. 

The spraying of trees bearing young fruit with copper car- 

' Southwoith, Journal of Mycology, vi. , p. ] 64. 
-Halsted, BnUetin of the Torrty Club, 1893, p. 109. 
Massee, Gardener's Chronicle, Vol. xiv. , 1S93. 



GLOEOSPORIUM. 483 

bonate or potassium sulphide solutions has good ett'ects on the 
yield of the orchards. In vineyards under treatment for l)lack- 
rot or mildew, there is little chance (jf tlie ripe-rut fun;j;us 
appearing. 

It is probable that the species knuwu as Ul. plwmoidcs 
Sacc. on tomato, Gl. pijnratum E. et E. on peppers (Capsicum 
"iiin'inn), and Gl. mdangcac E, et Hals, on the egg-plant, are 
identical witli GL friictigcnvm. At least they very much 
resemble each other, even on their widely ditt'ering substrata, 
and cross-infections have Ijeen carried out. 

Gl. venetum Speg. {Gl. necator Ell. et Ev.) Anthracnose of 
raspberry and blackberry.^ This disease appears on both canes 
and leaves. On the young shoots it produces small reddish- 
purple spots during early summer ; 'as the season advances the 
spots run together into irregular blotches of more or less 
greyish colour with a dark purple margin. The ripening fruit 
remains small and shrivels up. Leaves may also bear spots, 
but they more frequently remain smaller and have an unhealthy 
look. The conidia are at first enveloped in a thin covering, 
which l)ecomes gelatinous when wet, so that they escape. The 
mycelium is believed to perenn;ite in stems or decayed remains, 
and so to carry the parasite from season to season. Owing 
to the delicate nature of raspl)erry foliage, fungicides nuist be 
used with great care. J)ilui<' Bordeaux mixture is said to be 
safe and beneficial. The l)urning of diseased canes should 
• crtainly Ite carried out each autumn. 

Gl. ribis (hili. ). This attacks currant laishes tin-oughout 
I'^uroite and America in much the same way as Gl. inufntii. 
The leaves wither and fall, so that the fruit-crop suffers. 
( Ihitain.) 

Gl. amygdalinum IJrizi.- This has recently lieen described 
as dfsiiiitt.i\c i<i ahnond cultivatinu in Italy. The mycelium 
inhabits twigs and fruits, and gives dtl" lut'ts ul' conidi'iphures 
bearing conidia; as a result, wounds are pr<>ducc<l in the 
ei>id(?rmis and stunting of the h(tst-tissues takes })lace. 

Gl. rosae Hals, is described as injurious t<» rtise-cullure in 
America. It may be itlentical with some of the species of 
Gloivsjutriimi alreaily mentionecl as freipienling Kosaceae. 

' U.S. Aiiin-liu Ihjit. of AijiirnliHii , Id pint for 18H9, contains a goiiil account. 
- I'.ri/.i, Z'i/.tr/i. J. I'jlair.iidrankliiilm, \s'M\, p. ti.'i. 



484 FUNGI IMPERFECTI. 

Gl. ampelophagum (Pass.)^ Black-rot of the vine. This 
disease is very injurious and has a wide distribution in Europe. 
It is known under many names such as " Pock, Brand, Eost, 
Jausch, Brussone, and Nebbia nera," though probably these 
names include several distinct diseases. The identity of this 
Gloeosjjorium is somewhat uncertain, and it may really be 
identical with Pkoma amjx'linum (p. 467). Eathay ascribes the 
black rot to Sphacdoma (Phoma) amjielinum, w^hile Thiimen 
regards Crloeosporhim as the cause. Briosi and Cavara consider 
the two species of fungi as distinct. Thiimen says that the 
patches of Gloeosporium are for a considerable time disc-like 
and of a light-grey rose colour ; those of Phoma, on the other 
hand, are always depressed and brown. Eathay, however, de- 
scribes the spots of Phoma as at first dark brown, and later 
ashy grey with a brown margin. 

The spots appear on green parts of the vines during April 
and May. Those on the leaves frequently fall out, leaving 
holes. On the grapes the spots are smaller and produce a 
brown coloration extending deep into the fruit. The conidia 
are small, hyaline, oval, and unicellular ; they are abjointed 
from very short conidiophores arranged in little clusters. The 
conidial patches rupture the host-epidermis, and the conidia are 
liberated. 

Thiimen suggests that the soil of vineyards should be kept 
well cleaned, and that the stake mode of culture be used in pre- 
ference to an overhead trellis ; he also recommends the washing 
of all parts of suspected vines during winter with 10 to 15 
per cent, solution of sulphate of iron. This treatment is said 
to have been very beneficial in keeping many vineyards quite 
healthy and free from fungi. 

Gl. nervisequium." This parasite occurs on species of Platanus 
in Europe and America. Brown spots appear on the leaves, 
especially on the veins ; these as they extend cause sudden 
withering and fall of the leaves. Pustules containing a stroma 
develop on the spots, and unicellular, ovoid, hyaline conidia are 
abjointed from club-shaped conidiophores. 

1 Thiimen, Die Pocheii an Wein ?«. Ohst. 1885 ; Die Be/cumpfuw/ d. PilzkmvJc- 
heifcn, 18S6; De Bary, Annalen d. Oeno/ogie, iv. ; Viala, Leii maladien de la Vigne ; 
Briosi e Cavara, Funghi para»it . , iii. ; E. Ecithay, " Der B/ack-Bot," 1891. 

- U.S. America Department of Vegetable Pathology, Report for 1888, gives a 
general account of this disease. 



GLOEOSPORIUM. 485 

Several fungi of very near relationship, if nut acliially iilt'ntiial, 
occur on Platan us} All cause considerable disfiguration uf the 
foliage, so that a systematic destruction of all ynung diseased 
branches is strongly reccjinn'.ended. 

Gl. cingulatum Aiks' This is the cause of Anthracnose on 
J'rivet {Lujtistruin ctihjan) in the United States. The following 
is Atkinson's diagnosis : " Affected areas light brown, either 
oblong on one side of the stem or completely girding it. Acer- 
vuli 100 to 150 in diameter, rupturing the epidermis, in age 
black from the dark stroma lying in the base or extending 
irregularly up tlie sides, frequently forming a pseudopycnidium. 
Basidia numerous, crowded, simple, liyaline, or when very old 
}»erhaps faintly fuliginous. Spores oblong, or elliptical, straight 
or little curved, usually pointed at the base. From pustules 
on the stem they measure 10-20 by 5-7; in artificial cultures 
they are frequently much larger, but when crowded in the metlia, 
or when the nutrient substances are nearly exhausted, they may 
be considerably smaller. On stems of LiyHntruin viil;jan\ 

"This is quite distinct from Gloeosporinm li(justriiu(tn Sacc." 

Many species of Glocosporium frequent broad-leaved trees 
and causi- iiiDrc or less injury to the foliage. 

Gl. rhododendri Br. et ('a v. attacks tlie leaves of outdoor 
cultivated rhododendrons in autunni, or indoor species in 
winter. Large yellow spots marked with concentric zones 
are formed, and bear the pycnidia ; finally the leaves dry up 
and fall off. 

Gl. violae I'., et Br. attacks violets in Britain ami I'.S. 

Alll<-ric:|. 

Gl. vanillae < 'ke. et Ma.ss. {Calosimra ran ill a,' ^Mas.sre.-') 
This causes a dangerous disease on Vanilla planifulia ami other 
< )rchideae in Mauritius and other jiarts of the tropics. Death 
is brought about l<y the (iloeu.sjiorlnm (ffain.'ira) form of the 
fungus, the higher reproductive organs only appcariiiL; whi'u tlu- 
leaves are killed. 

< )ther species are known, Init llicir econonnc iiiip>rtanci' is not 

'v. 'l'ii\fl, liohiii. Zi'iliUKi, lSS(i; I^ccltic (111 S.iIpIiiii, Hinii iitti. tif J>t>titiii<itie, 
1 S!l-_>. 

- AtkiiiH<»n, "A New .Viitlir-iciiose of tin- I'livct," ('unull Vnir. Aijrir. Kr/Mi-. 
.S'tntiini linlhtin, So. 4'.l, ISK'J. 

' .\IilH.-,oe, K'lr Hull. Ill,, ISil'J, p. Ill 



486 FUNGI IMPERFECTI. 

Myxosporium. 

Conidia ovoid, hyaline, and abjointed from rod-shaped basidia 
situated in cavities of the cortical tissues of arboreous plants ; 
a true pycnidium is not formed, and the reproductive mycelium is 
only covered over by tlie epidermal layers of the host. 

Myxosporium devastans Eostr.^ is said to attack and kill 
young twigs of Bdula verrucosa. The conidial patches are 
developed in the killed rind, and give off unicellular colourless 
conidia. 

M. carneum Lil;>. is parasitic on twigs of beech. 

M. laneola Sacc. et Ronm. causes death of oak-twigs. 

The other known species have as yet been observed only as saprophytes. 



Colletotrichum. 

Conidial patches surrounded by setae ; characters very like 
GI()rosj)(n-i/nn. 

Colletotrichum Lindemuthianum (Sacc. et Magn.).- This 
disease, first observed by Lindemuth in 1875, has assumed 
great importance as a disease of the kidney bean {Phascolvji 
vulgaris) both in Europe and America. Young pods are most 
frequently attacked, but neither stems nor leaves are exempt. 
The pods show brown depressed spots with a distinct margin. 
The unicellular and oblong conidia are given off from short 
conidiophores developed on the spots. Germination takes place 
at once, the germ-tube forming an adhesion-disc on the host- 
epidermis, and from this a hypha penetrates into the tissues 
to develop into a brown mycelium. Frank obtained brown 
spots and mycelium on young beans twenty-four hours after 
infection. 

C. Lagenarium (Pass.) {C. oligocliaetum Cav.). This parasite 
is very injurious to seedlings of water melon (Cucumis citrullus), 
melon {C. Mdo), and the gourd {Cucurhita Lagenaria). Leaves 
and fruits may be attacked, but it is the cotyledons and stems 
of the seedling plants wliich most frequently fall a prey. Spots 

iRostrup, Tidsd-riftf. Skorraesni, 1893. 

- For the relationship of this with the following species, as well as their 
synouomy, see Halstecl in BnUetin of Torrey Botavical Club, 1893, p. 246. 
Description, treatment, and bibliography by Beach, " Bean-si^ot disease," Genera 
JS'. Y. Exper. Station Bvll(ti)i, No. 48. 



COLLETOTRICllLM. 



487 



appear on the leaves, and dt-pressions on the stem, sometimes 
extending so far round that the wlmlc shoot dries up. The 
conidial patches are very nnich the same nw tlie diflfrcnt liosts, 
and consist of short conidiophores from 
whicli oval, unicellular, hyaline conidia 
are alijointnl. 

C. lycopersici ('hest. is the cause nf 
a spot-disease on the fruit of tomato in 
the Unit.'d States. 

C. spinaciae Ell. et. JIals. causes a 
destructive disease on cultivated spinach. 

C. malvarum Br. et Casp. (C. a/tltaai> 
Southw.') jiinihices a disease of cultivateil 
hollyhock. It is most injurious to tin- 
seedling plants, and has caused great 
loss in America and Sweden. The fungus 
may attack any organ, and produces spots 
which enlarge so rapidly that death of the 
liost may result. 

C gossypii Soutliw.- Anlhracnose of 
Cotton, 'i'his disease, although it may 
lie found on stems and lea\'es, is most 
frequent and most conspicuous on the 
fruits or " bolls " of the cotton-plant. 
The first signs are tiny depressed spots 
of a reddish-brown colour, and as these 
enlarge they cause blackening of neigh- 
bouring tissue. When the spores are developed the spots 
become dirty grey, or perhaps ]iiid<ish if the spores are ]tresent 
in large numbers. Fruit attacked in this way does not mature 
well, and the yield of cotton is greatly prejudiced. Atkinson 
found the cotyledons easy to infect wiih tiie disease. 'I'he 
spores are obhmg and tajiering, with a shallow constriction in 
the middle; they are borne either on short colourless basidia 
or iin long, olive-coloured, septate setae, both kinds of conidio- 
phorc beiu'j jiroduced in aeer\uli or patches. 

C. adustum llll. is tin- raiisr nf ,1 li;if-s|i((t oil (>nui;:f in Fli.rid.i. 




FlO. •29S.—Colletotrichum Lixde- 
iiiuthianvm on jwd of Kidney 
Bean. Enlarged pustule and 
cunidia. 



Soutliwortli, 'A New Hollyhock I)i«ertae,' ./hi// /ci/ <;/ ,1/ ;/<(./(»///. vi., IS'.Hi. 
■ S.iutliwortli, JiniriKiI of Mj/iii/tiiij/, vi., IH'.K), p. UK). 
.Xtkinsnii, A/'il.fiiim .\'<irlr' Kj/'' r. Stii/imi Hull, tin. No. 41, IMVJ. 



488 



FUNGI IMPERFECTI. 



Faded spots appear on the leaves, becoming later greyish brown dotted 
over with minute black points, the conidial patches.^ 

C. ampelinum Cav. causes little dry spots on the leaves of vine, fie- 
quentjy in such numbers that the whole leaf dries up. 

C. kentiae Hals, attacks palm-seedlings so 
that their leaves do not unfold. 

C. cyclameneae Hals, occurs on Cyclamen. 



Scoleco-Allaxtosporae. 

Cylindrosporium. 

The white and shining conidial 
cushions are embedded in the host- 
plants. The conidia are filamentous, 
frequently somewhat twisted. 

Cylindrospormm Tubeufianum Alles- 
cher. This attacks the living green fruit 
of the bird-cherry, and causes the forma- 
tion of brown spots from which pustules 
break out ; the premature dropping of 
diseased fruits follows. In the locality 
where I observed this disease, numerous 
trees were attacked and most of the fruit 
on each was badly diseased. The my- 
celium spreads through epicarp and 
mesocarp, but does not penetrate into 
the endocarp, so that the development 
of the embryo is not directly interfered 
with. The conidia originate in pycnidial 
cavities without any special peridium ; 
their shape is given in the annexed 
diagnosis.- The pycnidial cavities arise 

under the epidermis which is afterwards ruptured and with the 

cells underlying it becomes brown and dead. 

'This note is taken from Underwood, Journal of Mycology, vir. ,but no 
mention is made of it in the later paper by Webber and Swingle (" Diseases of 
Citrous Fruits in Florida," U.S.A. Dept. of Agriculture Bulletin, 8, 1896). (Edit.) 

- AUescher gives the following diagnosis of this species : Pu>itulis primum 
convexis, epicarpio tectii, dein apptlanatifi ncutiformihusre, epicarpio rupto cincfi>i, 
nubcircxdaribuH, saepe cae-^pitosis vel conJlue.ntibuH, luteo-brunneoli'^, subfurfuraceis ; 
acerimlift, minutis, innatis, erumpentibus ; conidiis Jiliformitnis, curvatis vel flex- 
uosis multiguttidatiH, hyalinis 40-60 = 2-3/x. Hub. in fructibus immaturis Prnni 
Padi, quos necat. 




^^--yC-o 



Fig. 299. ■ — Cylindrosporium 
Tuhcujianuiii on fruits of Prunus 
Padui. The unshaded parts re- 
present parts still green and 
living, although bearing pustules 
here and there ; the remaining 
parts are completely beset by 
pustules, so that the cells are 
killed and brown. 4 natural 
size. (v. Tubeuf del.) 



CYLINDROSPORIUM. 



489 



As yet the disease has been observed in quantity only in 
the neighbourhood of Oberammergau (Upper Bavaria). 

C. padi Kaist. Leaf-bh'glit of clierry and plum. This dis- 
ease is most destructive in the nursery, causing premature 
defoliation of young trees ; it may also cause severe injury to 
fruit-bearing trees. The leaves become spotted and perforated 
by holes caused by the falling out of withered spots. Spraying 
with dilute Bordeaux mixture early in the season is said to 
liave "ood effects.^ 




IK 



Fio. :J00.— A fruit from Fig. 2110 (enlarged). A, Two pustules still further 
enlarged. B, Pustules before and after rupture of the epidermis, f, Isolated 
cunidia. (v. Tul^euf del.) 

C. filipendulae Thiini. occurs on leaves of Spiraea FHipeii<Iiihi. 

C. ficariae lli-ik. On leave.s of Ranunndun Ficaria. (Britain.) 

C. viridis E. ft E., and C. minus E. ot E. On K-avcs of Fi<i.iiitii.i rinifi.i 
in till- Ciiitt'd States. 

C. cercosporoides E. et E. On living leaves of tulij) tree. 

C. saccharinum E. et E. ()ii livini,' leaves of , !<•"/• .■«i,;-/,ai-iti)t/n in the 
(nited States. 

Cryptosporium. 

('(jiiidial cushions shaped like ])yeni(lia. Cunidia rixl-likt' (ir 
Spilldlr-sliapcl. 

Cryptosporium leptostromiforme Kiihii.-' This fiingus fnrms 
rn\vs (if black stidinala mi lln; stems ul' Jujiiiics: in ibc slrniuala 
are tuiined iiycnidia-like cavities with several lurk-like (>]ienini^s, 
and in them cunidia are ^iveii oil' from coniilidjphnies. The 
conidia are rods with mnnded ends 7->^''>in loii'^ and abmit 
- fi broad : they emerge linm ihc necks of the cavities as 
long tendril-like chains, and may be continuously «4iven oM 

' Fainliilil {Jounia/ <>/' .1/ ;/«■(,/,,.///, \ii., p. '2V.>) jjivuH rcbults of uiiii.liiil 
t ri;atiiieiit. 

-.1. Kiiliii. Ji.rirhi, ,/. h,„'hr,,ih. l„->l.. Hiille, I.SSO. 
FiHeliiT, " <'ri//ilin/,„iiiiiii /' /i>'i>/,iiiiii/iinil' ." Hre.slail, 1 SO.'l. 



490 FUNGI IMPERFECTI. 

throughout the whole summer. Fischer has proved experi- 
mentally that the conidia germinate easily in water, that the 
germ-tubes penetrate into living lupines, and produce a mycelium 
which spreads through stems and leaves to develop stromata on 
all the organs of the plant. The formation of both pycnidia and 
conidia goes on throughout the autumn and following spring on 
dead plants, the fungus being capable of living as a saprophyte 
and of hibernating. The disease may occur with great severity. 
Fischer describes cases wdiere more than the half of the plants in 
a field were attacked and died before flowering or soon after. 
There is thus a loss not only in lupine seed, but also in the good 
effects which the crop has as a " green manure." 

Fischer gives the following measures for keeping this pest 
in check : " Where the fungus has obtained a footing, lupines 
should not be planted till at least the year after next, and then 
only as a catch-crop on stubble : it would be still safer to keep 
lupines off the land till the third or fourth year. After lupines 
as a catch-crop, they may safely be sown again in spring as a 
seed crop, after the lapse of a clear year. No lupines should 
be cultivated near diseased fields. Instead of ploughing-in a 
catch-crop of lupines directly, it should be dried and used as 
litter for cattle, because the excrement has been found to kill 
the fungus ; the lupines after lying over winter in the manure- 
heap could then be used as manure in spring. Similarly when 
the lupines have been grown for seed, they should be closely 
mowed down so that little stubble is left ; the straw may then 
be used for litter." 

This fungus has not as yet been observed on plants other than 
lupines. 

DiDYMOSI'ORAE. 

Didymosporium. 

Conidia brown, oval or spindle-shaped, bicellular, and not 
i:)roduced in chains. 

Didymosporium salicinum Vuill. Vuillemin reports this as 
very destructive to the Osier cultivation in Bourgogne. 

Marsonia. 

Conidia transparent, two-celled, and not produced in chains. 
The species live on leaves. 



MARSONIA. 491 

Marsonia juglandis (Lil-.) produces on leaves o{ Jwjlans little 
greyish yellow spots with brown margins ; thereon stromata are 
formed, which rupture the epidernris and liberate the large sickle- 
shaped conidia. (Britain.) 

M. populi (Lib.). On leaves uf .species of l'vpiif>i.< in Europe and Britain. 

M. potentillae (Desm.). On species of Potentilla. (Britain.) 

M. campanulae Bres. et All. On Campanuhi latifoUa. 

The following; are North American species : 

M. toxicodendri (Ell. et Mart.). On Khus To.rivocfendron. 

M. quercus Peck. On (Juercus ilicifoUa. 

PflRAGMOSroRAK. 

Coryneum. 

The conidial patches are black and disc-like, and rupture the 
host-epidermis. The conidia are oblong or spindle-shaped, 
yellowish, and pluriseptate ; they are abjointed fr<»ni short 
conidiophores. 

Coryneum Beyerinkii < »ud.' This is stated by lU-yerink to 
be the cause of a '" gum-tlux " of cherry and allied species of 
Rosaccae. Tt is the corridial form of Ascospora (see p. 211). 

C. camelliae ]\Iass.- occurs on living Camellia leaves at Kew. 
(Ihitain.) 

Pestalozzia. 

Conidia spindle-shaped, with two or more brown nu'(Han cells 
and hyaline terminal cells, tlie one at the free end carrying 
several ciliate processes. 

Pestalozzia Hartigii Tub." Tin- external etlects of this 
disca-f ha\(' hfcn long known, although tlie fungus causing it 
has only been recently detected. It attacks ynuug ]ilants of 
various trees and shrubs. The sym])toms are yellow discoloration 
of the foliage, and constriction of the stem just ab(jve tin* level 
of the S(jil, followed by death of the whole jdant. At tin- 
constriction of the stem tlu' rind uraihially tlries up. whereas 
nciuddjourini,' portions continue to ^row in thicknt'ss till finally 
the bulk is rupture(l ( Fiuj. ilOl'). In tin- U\iiiL: pari of the 

' OmteiiiunB, I/nlirii/in, ISS.S. 
-(.'ooke, (irtnlltii, xx., p. 8, IsiH. 

^ V. Tuliciif, Jifitnii/r :nr Kntulnix'< il. /{iniiiiLi'iidfn itm, 18NS ; aiul Fornt/irh- 
iicifiinrlxM. Xi llxrhrit'l, iHihi. 




Fig. 301. — PestalozzUi Hariigii. Young Spruce Fig. 308. — Peslalozzia Hartlgii. Conidia and coni- 

showing constriction just over the surface of the diophores on part of stroma. (After v. Tubeuf.) 

soil. (After v. Tubeuf.) 



I'ESTALOZZIA. 



493 



rind of young plants of spruce and silver tir, I succeeded in 
finding near the place of constriction, a delicate mycelial stroma 
enclosing some cavities (pseudopycnidia). Conidia were formed 
inside these cavities and emerged to the exterior. They belong to 
the genus Pestalozzia, and have two brown median cells, a trans- 
parent stalk-cell to which the long stalk is attached, and a 
transparent terminal cell carrying two or three transparent thread- 
like appendages (Fig. 30-")). Germination results in the emission 
of a strong germ-tube from one of the three lower cells. If at 
any time the conidia dry up, the two clear trans] )arent cells 




Fifi. 304.— /*..<(<'/'-:;;.' /■, ■ II (l,o> //),«/■,,< .1/. ,i:,.,.o. At tho J.laocs 

marked X cambium and riud have been killed, so that ^owth in thickness no 
longer takes place ; the hijfhcr jiarts, hcjwever, have continued to thicken, but 
are gnidually dying, (v. Tubeuf jdiot.) 

collapse and the ai)i)endages easily fall oft", so that on material 
of this kind the conidia are only two-celled and brown. The 
mycelium after cultivation in nutritive gelatine soon juddiues 
conidia. 

This fungus was found by iJostnip ou brceli, producing luucb 
the same effects as just descrilx'd. On this host it has been 
found very destructive in young naturally regenerated forest, 
the loss in l>avaria and Wurtcmlmrg within very recent years 
having Itecn estimated at ."lO ]ier cent. It also occurs on ash. 
sycanioic, and other trees. 

P. funerea l><'sm. (Uiitain and I'.S. Anirrica). 'I'bf si)ori'S of 



494 FUNGI IMPERFECTI. 

this fungus were found by Boehra^ on diseased cypress trees, and 
although investigations are not yet complete, it is believed that 
this Pcstalozzia is the cause of a well-known disease on cypress. 
The symptoms on Chamaccyparis Mcnziesii are local constriction 
of stems and branches, and death of portions beyond. The rind 
and cambium of constricted places are killed, the bark becomes 
split, and the wood dries up. P. funcrea is a well-known sapro- 
phyte on twigs and needles of Cupressus, Juniperus, and other 
Conifers ; its occurrence as a parasite has been suggested several 
times. 

P. gongrogena Temme" is said to cause the canker of willow. 
In diseased willows Temme found an intercellular and an 
intracellular mycelium with pycnidia and conidia of Pcstalozzia, 
but other pycnidia of unknown affinity were also present. 

P. insidiens Zab. On bark of Ulmvs americana. (U.S. 
America.) 

P. phoenicis Grev. causes a disease on indoor cultivated palms. 

The following are some of the more important forms frequenting 
living leaves : 

p. Guepini Desm.^ (U.S. America). The conidia of this species 
are found on large spots with dark margins on living leaves of 
Camellia japonica, Magnolia, Citrus, Rhododendron, and other 
plants. Spore-patches appear on the epidermis, and give off 
conidia embedded in a mucilaginous slime. The conidia have 
three dark median and two hyaline terminal cells, the distal one 
bearing the characteristic appendages. The leaves are permeated 
with mycelium and fall prematurely. 

P. inquinans C. et Hark. On Eucalyptiis in California. 

P. stictica B. et C. On Flatanus occidentalis and Tilia in United States. 

P. concentrica B. et Br. On leaves of Crataegus, Pyrus, Castanea, and 
Quercvs in North America. 

P. suffocata E. et E., and P. discosioides E. et E. On cultivated and 
wild rose shrubs in America. 

Pestalozzina. 

Conidia similar to those of Pcstalozzia., but all the cells 
hyaline. 

^ Zeitschrift f. Forst. n. Jayd-iveseji, 1894, p. 63. 

^Thiel's landwirth. Jahrhuch, 1887; and Ba: d. deufsch. hotan. Ges,, 1890. 
'■'' Aiinal. des Science natur., Ser. ii., Vol. Xlii., 1840; Briosi et Cavara, Funghi 
parasit. , vi. 



PESTALOZZINA. 



495 



Pestalozzina Soraueriana Sacc.^ occurs on foxtail ^n-a.ss 
{Alopecurns pratensis). The conidial tufts develop on spots which 
appear on the gradually witlierin;^ leaves. The bristle-appendages 
on the terminal cell of the eonidia are lateral, only one heing 
tt'rminal. This disease was first observed bv Wcinzierl at A'it-nna, 



«r-***»Vr?:V 







Fl<;. :i()o.—S-j'to'jlo't'.„i Jhnti'ilanuin on Ao ,- <•(•,«/)..<?,.. Tliu <lc.iA twi^s exliibit 
black iM^iiits and linc.s--the jiycnidia of the iiur.usitc. (v. Tubciif pliiit.) 

and has not as yi.-t been found out of that nt'ighbourhoud ; ii 
attacks the pure-culture seed-beds only. 



Septogloeum. 
Like ^7("M^y//</■/■/////, cxiTi.t that it lias jiliiricelliihir i-diiidia. 
Septogloeum Hartigianum Sacc.-' Twigs of the conmu.n 
iii;il>lf (J"/- KiiiijKs/o ) are subject to a disease, whicli e.\hil»ils 

' .Soriiiier, Zi itMchri/t /. J'flnnztiikiniikhiittn, 18!I4, p. '2\'A. 
- R. Hiirtig, Foritliifiiiatiiririns. Ziitirhrij't, 18!»L*. ji. "JS'.l. 



496 FUNGI IMPERFECTI. 

itself in the drying-up of young twigs before their buds open 
in spring. The older branches, however, assume their normal 
foliage. Examination of diseased twigs reveals the mycelium 
of a parasitic fungus living both inside and between the 
cells of rind and wood. Conidial patches break through 
the host's epidermis about May as long greyish-green lines. 
The conidia are hyaline, three-celled, and cylindrical with 
rounded ends ; the conidiophores are short thick rods. In May 
and June the spores are capable of infecting new hosts, and 
germinate in a few hours. Infection of twigs takes place in 
summer, and the mycelium spreads through the first-year 
shoots, without, however, giving any external indication of its 
presence till the follow^ing spring, when the twigs dry up as 
already described. 

S. ulmi (Fr.) may be a form of PhyUachora ulmi. The 
mycelium lives in parenchymatous cells, and causes the formation 
of brownish-yellow spots on leaves of the elm. The conidial 
patches form tiny points on the lower surface of the leaf; they 
consist of pycnidia-like structures without a peridium, arising 
from a stroma developed under the epidermis. The conidia are 
spindle-shaped and pluricellular. 

S. mori (Lev.) is stated by Briosi and Cavara to produce yellow 
spots with brown margins on the leaves of Morns alba and M. nigra. 
Death and premature defoliation of the host then take place. 
The conidial patches develop under the epidermis, and rupture 
it as the conidiophores emerge ; they have no real peridium, 
hence the fungus cannot belong to the group Phhosijora, as 
Saccardo supposed. The conidia are long, cylindrical or fila- 
mentous, and pluricellular. 

Amongst the more important North American species are : 

S. profusum (E. et E.). On living leaves of Corylus 
amcricana. 

S. fraxini TTark. On Fraxinus Oregana. 

S. apocyni I'eck. On Aijocynum cminahinnm. 

III. HYPHOMYCETES. 

Conidia produced neither in pycnidia as in Sphaeropsideae, 
nor from a special stroma as in Melanconideae, but free on 
conidiophores given off from the mycelium. 



HYPHOMYCETES. 497 

The group is subdivided into the families of the Muccdineac, 
Dematieae, Stilbeae, and Tuhercularieae} 

I. FAM. MUCEDINEAE. 
1. Sect. Amerosporae. 
1. Suhsect. Micronemeae. 

Oospora. 

Conidia, transparent or only slightly coloured, globose or 
ovoid, non-septate, and produced in regular chains from simple 
short conidiophores ; they thus resemble the genus To'nda in the 
Di'jixifini' . 

Oospora scabies Thaxt.- is said to cause the well-knuwn 
scab or scurf on beet and potato. This consists in portions of 
the surface of the subterranean tubers swelling out as rouf'h 
brown excrescences. Other authors ascribe this disease to 
bacteria. 

Microstroma. 

funidia unicellular, transparent, oval, and shortly stalked. 

Microstroma album (Desm.). Tins, although common on 
living leaves of several species of Querent, is not a serious 
disease. The conidial patches on the under side of the loaves 
arc white and very thin. (liritain.) 

M. juglandis (Bereng. ) frequents tlie leaves of Jurjhin.^ ngia 
and ./. (iiirri'n in Europe and Xurth America. 

Monilia. 

Conidia oval or spindle-shaped, and j)r«xlueed in chains from 
bi'anelied coiiiilinjiliores. 

Monilia fructigena Pers. (Ihiiain and I'.S. Aiuerica.) i'his 
is ihe cause of eertaiii widespread diseases — the brown-nil ol' 
cherry and plum, the jjeach-rot, and a rot on apples and pears. 
It has Iteen the subject of many papers since Thiiaien lirsi 
described it in 1879.^ All parts of tiie host are attacked, and 

'This i.s tlie arrangement fdllowetl hy MasHi'i-, " Jirif<.Kh Fuuijwh Floiii," \'o\. 
III.; there the eharaeters of the various suh-ilivisions may l)e obtained. (Kdit.) 

■•'Thaxter, Connect irut Aijnr. Erptr. Station, liejwrl, 189(). 

•'AnionvHt the more iniportaiit tlcHeriptions are: Thilmeii, Fiiii'/i /'mnirofu, 
IST'.t; Smitli (Worth. <i.), l.'inli m r's Chrunich, ISS.'), p. .VJ ; .\rtlair, A'mc yurk- 
Ai/rir. h'jjiir. S/tifion, IV., LSS."). 

•J I 



498 



FUNGI IMPERFECTI. 



exhibit reddish or yellow spots ; therein the mycelium spreads 
rapidly and gives off tufts of conidiophores which rupture the 
epidermis. The conidiophores are septate, branched, and give 
off' chains of unicellular oval conidia. Meanwhile the affected 
fruit becomes rotten and gradually shrivels up, it remains, 
however, hanging on the tree throughout the winter. During 





Fig. 306. — Monitia fruclkjena. A, Apple showing the grey conidial patches as 
more or less concentric lines. B, Young Peach, slirivelled up in consequence of 
attack, (v. Tubeuf del.) 

next spring, when the fruit is again moist, further conidia are 
given off'. Infection takes place by wounds or even through 
the epidermis of young leaves and blossoms. The conidia have 




Pig. 307. — Monilia fructiqena. Branched conidiophore with chains of conidia. 
a. Branched hypha of Monilia in the tissue of an Apple, (v. Tubeuf del.) 

been found to retain their vitality for two years. Smith ^ 
found that twigs were also affected by the disease, so that a 
gummy degeneration took place in the soft bast and cambium. 
As remedial measures, the gathering of all diseased fruit left 
hanging over winter is strongly recommended. This, as well 
as other diseased parts, should be burned as soon as possible. 

^ Smith (Erwin), Journal of Mycoloijy, vii., p. 36. 



MOMMA. 499 

"Washing of stems with a sohitioii of iinii sulphate in spring 
before the buds unfold is suggested, also spraying of young 
foliage with dilute Bordeaux mixture. 

Oidium. 

Mycelium epiphytic on living plants. Citnidia unicellular 
and barrel-shaped, produced in chains on erect eonidiophores. 
Many have already been proved to he conidial forms of 
Erysipheae. 

Oidium erysiphoides Fr. frecj^uents living leaves of hop, 
clover, cucumber, cic, and is proljably the conidia of species 
of Uri/siphr on these hosts. ( IJritain and U.S. America.) 

0. Tuckeri Berk. On leaves and l)erries of the vine (see 
J^iii-i ii iijii , |i. 176). 

0. leucogonium Desm. On roses; probably the cunidial form 
(;f ,'<jiliih rnHi.ni paiinosa (see p. 172). 

0. farinosum Cooke. On living leaves of apple-trees. 
< Britain.) 

0. chrysanthemi IJabh. On leaves of cultivated chrysan- 
themum, (ihilain.) 

0. aceris Rabach. On leaves of Acer Pseudoplatanm. It is 
proltably llic cunidial stage of Uncinula hieornix. (Britain.) 

0. mespilinum Thiim. On leaves of medlar. (Britain.) 

0. destruens Peck. On Amdanchicr canadensis and Prnnus 
-'i-ntinii in America. 

0. tabaci Thiim. ()n leaves of tobacco. 

monilioides Link, probably the conidial stage of Eri/siphc 
ijraniinln, occurs on living grasses over the whole world (see p. 175). 

2. Sub-sect. M'lcronemeae. 

Botrytis. 

Mycelium grey. Conidia nujre nr less spherical, and pro- 
<luced in aggregations on the ends of branched conidiophores. 
•Many of the species are saprophytes, others are parasitii- on 
plants or insects, and others form sclerotia : the latter have 
dready l)een considered under Schrutinia (see p. 2(j7). Tlie 
lollowing an; known to 1)6 parasitic on plants: 

Botrytis cinerea I'ers. This enemy of many plants has already 
men noticed as Sihrotinvi Fuchiliniui ; so also Ji. Dntnjliisn Tulieuf. 



500 FUNGI IMPERrECTI. 

B. galanthina Sacc. occurs on the bulbs of Galanthus nivalis 
in Britain. 

B. parasitica Cav. produces sclerotia and conidia on Tulipa 
Gcsiur'ni iiK in Italy (Sclcrotiam tulipac). 

B. vulgaris Fr.^ This is a very common species, and includes 
several well-marked varieties. It is 'said to be parasitic on 
cultivated lettuce causing a " leaf-rot." 

B. fascicularis Sacc. is reputed to be the cause of a " fruit- 
mould " on the egg-plant {Solanum Meloiujcna) in the United 
States. 

A Botrytis is figured by Atkinson- as frequent on diseased 
carnation -plants. 

Ovularia. 

Conidiophores simple except for tooth-like projections near 
the apex on which the conidia are developed. Conidia uni- 
cellular, colourless, solitary, rarely in chains. 

" Closely allied to Ramularia, but distinguished by the one- 
celled conidia" (Massee). 

Ovularia pulchella (Ces.). Briosi and Cavara distinguish this 
as a disease of Lolium italicum in Italy. The leaves become 
black-spotted and permeated with an intercellular mycelium, 
from which arise the erect, branched, septate conidiophores. The 
more vigorous conidial patches have a delicate rose colour. 

0. necans Pass, produces large spots on the foliage of quince 
and medlar, so that the leaves gradually wither and dry up. 
Conidia appear as a white powder on the dead remains. This 
fungus is recorded from both Italy and France. 

The following are British species occurring on leaves ; several 
of them, however, are placed by Saccardo under Ramularia : 

Ovularia lychnicola (Cke.) Mass. On Lychnis diurna. 

O. senecionis (Sacc). On Senecio vulgaris. 

O lactea (Desm.). On species of Viola. 

O. armoraciae (Fuck.). On cultivated horse-radisli. It is reported as 
somewhat destructive in the United States. 

O. interstitialis (B. et Br.). On under surface of leaves of primrose^ 
forming yellow spots in the angles of the veins. 

O. primulana Thiim. On leaves of Primula. 

O. cochleariae ((Jke.). On Cochlearia officinalis. 

^ Wehmer on species of Botrytis, Zeitschrift f. Pflanzenkrankheiten, 1894. 
2 Atkinson, "Carnation Diseases," at Amer. Carnation Society, 1893. 



UVULARIA. 501 

O. alnicola (Cke.). On A huts t/lutinosa. 
O. scelerata (Cke.). On Ranunculus sceleratiis. 

O. rosea (Fuck.) produces irregular brown spot.-^ on tlie leaves of 
v'arious species of willow. 

O. asperifolii (Sacc). On Sjpnphytum ojicinalts. 

O. veronicae (Fuck.). On .spot.s on leaves of Veronica Chamaedn/g, etc. 

O. lamii (Fuck.). On Lamium. 

O. syringae (Beik.). On Syringa. 

O. sphaeroidea Sacc. causes spots on leaves of Lotu.'t. 

O. carneola Sacc. On spots on leaves of Scropludarin nodom. 

O. bistortae (Fuck.). On sj)ots on leaves of Polygonum Bistorta. 

O. obliqua (Cke). On leaves of Runxex. 

2. Sect. DiDYMu.sroiiAE. 

Didymaria. 

Conidia two-celled, colourle.s.s, and produced siiioly at the 
exti«'niity of siin])le erect conidiophore.s. 

Didymaria prunicola Cav. Cavara states that this causes 
raised roundi.-ih spots on the upper surface of leaves of plum : 
finally the leaves gradually dry up and fall off. Slender two- 
celled conidiophores are produced, and give off each a two-celled 
obovoid conidiuni. 

D. Ungeri (onl. On living leaves of Ranunculus repens. (Britain.) 

D. astragali (Kll. et Hoi.). Found on leaves of Astragalus canadensis. 

D. spissa Hark. (Jn leaves of Solidago occidental is ; both species in 
North Aini-rit-a. 

Bostrichonema. 

Conidiophores erect, spirally twisted, unbranched, and non- 
septate. Conidia elli])tie or oblongs two-celled, and hyaline. 

Bostrichonema alpestre Ces. ( )n living leaves oi Fo/i/i/oiwui 
via Jill rii III and /'. Uistortu. (IJritaiii.) 

B. modestum (15. et 15. AVhite). < >u leaves of Alrlnniillu 
tiljiuKi. (I5ritaiii.) 

:'.. SkcT. I'MIIA'iMiiSPuR.VE. 

Ramularia. 

( 'oujiliophoies eiiier'..;iiig in tiit'ts from the stouiala : they give 
oil' a terminal conidiuni, then bend o\cr ami jiroduee a hileral 
conidium, ami so on they liiamh in a syni|iodial manner, pro- 



502 FUNGI IMPEKFECTI. 

ducing conidia at the end of each branch. Conidia septate 
oval or cylindrical, and light-coloured. 

" The parasitic habit, simple or sparingly branched hyphae, 
denticulate and bearing the septate conidia at the tips, charac- 
terize the genus, which differs from Ondaria only in the 
septate conidia " (Massee). 

Ramularia cinarae Sacc. is said by Prillieux^ to have caused 
great destruction in the cultivation of artichokes. The leaves 
became spotted and died, so tliat no flower-heads were produced. 

The following are British species : 

Ramularia hellebori Fuck. On leaves of Hellehorits foetidus and H. 
viridix. 

R. epilobii (Sclm.). On leaves of Epilohium. 

R. ulmariae Cooke. On leaves of Spiraea Ulmaria. (U.S. America.) 

R. geranii Fuck. On under surface of leaves of various species of 
Geranium. 

R. lampsanae (Desm.). On Lampsana and Hypochoeris. 

R. pruinosa Speg. On Senecio jaeobea. 

R. plantaginis El. et Mart. On leaves of Plantago major. (U.S. Am.) 

R. variabilis Fuck. On leaves of Digitalis undVerbascum. (U.S. America.) 

R. calcea Ces. On leaves of Glechoma hederacea. 

R. urticae C!es. On leaves of species of Urtica. (U.S. America.) 

R. pratensis Sacc. On Rtimex Aeetosa. 

R. rufibasis (B. et Br.). On Myrica Gale. 

Some of the more important North American species are: 
Ramularia rufomaculans Peck. On the buckwheat {Fagopyrum escvlen- 
tum), it has ])i'oved a somewhat injurious fungus. 

R. albomaculata Peck. On leaves of Garya americana. 

R. viburni E. et E. On leaves of Viburnum Lentago. 

R. celtidis E. et K. On leaves Celtis occidentalis. 

R. desmodii Cooke. On leaves of various species of Desmodium. 

R. brunnea Peck. On living Tussilago farfara. 

R. areola Atks.- This causes spots on the foliage of cotton. 
" Spots amphigenous, pale at first, becoming darker in age : 
irregular in shape, limited by the veins of the leaf, conidia in 
profusion giving a frosted appearance to the spots. Conidio- 
phores fasciculate, in small clusters distributed over the spots. 
Conidia oblong, usually aliruptly pointed at the ends" (Atkinson). 

R. Goeldiana Sacc. is said to kill leaves and twigs of Coffea 
orahira in lirazil. 

^"Maladie d. Artichauts," B}iUetin dc la soc. mycolog. de France, 1892. 
-Atkinson, Botanical Gazette, xv. , 1890, p. 166. 



PIRICULARIA. 



503 



Piricularia. 

Conidia grey, pluricellular, somewhat pear-shaped, and pro- 
duced from tlie a])ex of simple erect conidiophores. 

Piricularia oryzae Br. et Cav. This species is described 
by Briosi and Cavara as causing a disease of rice in Northern 
Italy. The plants become spotted and reddish-])ro\vn in summer, 
finally withering. The conidiophores arise on the spots on the 
lower surface of the leaf, and bear light-grey three-celled 




Fio. 308. — Mastigotporium aWuii). (v. Tubeiif del.) 

conidia. Diseased plants may lie found 1>earing this fungus 
only, frequently however it is in company with other fungi. 



Cercosporella. 

Conidia hyaline, similar to th(jse of t'lrcoxporn, and produced 
from sinijilc or branclicil hyaline conidiophores. 

Cercosporella persica Saec. is parasitic on living leaves of 
peach. Ill .Viiicrica it has been known since ISllO, and receives 
the naiiiL' of "frosty mildew." It causes yellow spot.s on the 
jow.-r surface nf the leaf. 

C. pastinacae Karst. (jccurs on lising leaves of cuhi\ated 
jtar.siiip. 



504 



FUNGI IMPERFECT!. 



Mastig-osporiura. 

Conidia hyaline and four-celled, frequently bristled. 

Mastigosporium album Eiess. produces oblong dark spots 
with light margins on leaves of living grass. The conidia 
are produced on the margins of the spots {Fig. 308). 



Fusoma. 

Similar to Fusarium, l)ut the mycelium is loose and not 
Conidia spindle-shaped and septate. 



aggregated into a tuft 




Fig. 309. — Fusoma paraslticum. Dis- 
eased Pme-seedliiigs, with, a, root killed ; 
b, hj'poootyl killed ; c, first leaves aud 
plumule killed. (After R. Hartig.) 




Fig. 310. — Epidermis of a Pine-seedling 
with a stoma. Some hyphae of Fusoma 
have produced partial dissolution of cell- 
walls. (After R. Hartig.) 




Fig. 311. — Fusoma parasilicum. Coni- 
dia— immature, mature, aud germinat- 
ing. (After R. Hartig.) 



Fusoma paraslticum Tub.^ is the cause of a disease of seed- 
lings, particularly those of Conifers. The first symptoms are 
dark patches on the seedlings, followed by their collapse. There- 

1 R. Hartig, For^tlich-naturrvisH. Zeitschri/f, 1893, p. 432. 



FUSOMA. 505 

after in moist weather or under artificial cultivation, a 
light-grey mycelium appears bearing numerous slightly curved, 
tapering, pluriseptate conidia (Fig. oil). In liavaria and 
Baden this parasite has caused great loss in the seed-beds of 
conifers. 

F. inaequale Iloyer. On living leaves <jf Taraxaemn ojficinale. 

Septocylindrium. 

Conidia cylindrical, hyaline w pale-coloured, with two or 
nirtre septa, and produced in chains. 

Septocylindrium aromaticum Sacc. occurs on living Acorits 
Ciihi nil's, killing leaves and even plants. The mycelium grows 
intercellularly and produces spots. The conidiophores emerge 
in tufts from stomata included in the spots, and give olf long 
thread-like, pluriseptate, hyaline conidia. 



2. FAM. DEMATIEAE. 

1. Skct. Ameku.si'urae. 

1. Snbsect. Micronemeae. 

Many of the genera of this subsection contain species i'ound 
on the living leaves of plants, l»ut none of tlieiu are yet of 
economic importance. 

2. Siihstct. }fiii-ronemeue. 

Hormodendron. 

Mycelium grey, epiphytic, and creeping. Conidiojihores erect, 
branched, and septate. Conidia spherical or ovoid, unicellular, 
and )iriMhicc(l in chains. 

Hormodendron hordei I'>i.' Tliis producis a characteristic 
spotting III the haiihiis ;iiiil leaves of barley, accttnii>anicd by a 
stunting of the whole plant and jxmr develnpnient i»f the eai-s. 
'i'his is not a true parasite, but when it aj)j)ears in (luantily 
il has consideraltle effect, attacking whole fields and causing 
great injury. 'I'he sp(»ls and c<»ni(Ua are fnund also t.n wild 
Hin-ihuia inn li III! Ill on the margins of roads and lields. 

' llniliM.' ill Zopfs liiilntif :. /'hi/iio'. ". .V.. <•/,//. ./, ,/,.,/. nfi<i>n~i,i- n. iv., 
JH'M. 



506 FUNGI IMPERFECTl. 

2. Sect. Didymosporae. 

1. S'n.bsn'ct. Micrunemeae. 

Dicoccum. 

Conidia oblong, two-celled, and arising from short simple 
conidiophores. ^Mycelium subcuticular. 

Dicoccum (Marsonia) rosae (Bon.) causes brown spots on 
living leaves of roses, and a premature leaf-cast takes place. 
Little mycelial stromata develop between the epidermal cells 
and their cuticle, and give off two-celled hyaline conidia. 

D. uniseptatum B. et Br. forms dark patches on twigs of 
Glcrnafis cltnlhu. (Britain.) 

D. lathyriimm Ell. et CTall. On living leaves of Lathyrtts 
ochrolcucus in America. 

Cycloconium. 

Mycelium subcuticular. Conidia one- to three-celled. 

Cycloconium oleaginum Cast.^ When this fungus is present, 
the leaves of the olive show roundish light-brown spots with 
dark margins, then becoming discoloured, they roll up and drop 
off. The mycelium grows in the walls of the epidermal cells, 
branching dichotomously ; branches of the hyphae break out 
through the cuticle as sac-like cells, which become the conidio- 
phores. The conidia consist of one to three cells. Kruch 
states that Cercoqjura cladosjwrioides is often present along with 
this disease of the olive, and may take some part in causing it. 

Peglion states that this or an allied species occurs on leaves 
of Quercus Ilex. 

2. Suhsect. Macronemeae. 

Passalora. 

Conidia oblong or Spindle-shaped, two-celled, and borne on the 
apex of greenish pluriseptate conidiophores, arising from an 
olive-green mycelium. 

Passalora bacilligera INI. et Fr. occurs on living leaves of 
Alniis ghitinosa. (Britain.) 

P. microsperma Fuck. This frequently covers the whole 
lower surface ol' the leaves of Alnvs incana with little tufts of 

' Kruch, Bullelm soc. hot. UaL, 1892. 
Boyer, Herherrhes .sur Its maladies de VOlivicr, Montpellier, 1892. 



PASSAL<»RA. 



50( 



brown septate conidiophores, bearin;^ lunir, twd-ct'lli-il, oliuvate 
coiiidia. 

Fusicladium. 

Mycelium greenish and sparinj^dy septate. Conidiophores in 
tufts, short, erect, and bearing terminal eonidia. Conidia ovoid 
or clavate, and one or two-celled. 

The species are conidial forms of Vrnturia, and have already 
been considered. Some of the better-known forms an- : 

Fusicladium dendriticum AVallr. (liritain and U.S. America). 
Tins allacks llie leaves, sliools, and fruits of tiie api»le (see ]>. 21 S). 




Fk). ^Vl.— Vtntvria (FimifUutiiuit) tlendriticuui foniiilig brown «ii<it8 on un 
apple ; those still in the earlier stages have a radiate margin and War conidia. 
'I'he cnliirged section shows two rows of large-celled parenchyma of the apple, 
covered bv a stroma of i)seiidi "parenchyma bearing conidiophores and conidia. 
(V. TuU-iif del.) 

F. pirinum (Lib.) (I'.S. America). This is a cause of 
"spotting" on leaves and fruits of tlie .pear, also of species of 
Crfifatf/us aiul Amclanchii:i: The conidial i)atches are lirowni.^h 
in colour. Teglion states liiat this parasite forms sderutia in 
the bark of twigs. it is ])rol»al»ly a conidial form of Venturin 
ililiiiliii mr. I'lji'i- 

F. cerasi (K'abh.) attacks the cheiiy orchards with such 
viruleii<t' that the cidp may be rendered ijuite im.-^aleabK'. 

F. eriobotryae Cav.' Cavara states that this attacks tii.- 

'Ciiviiiii, A'i'(/'-''i (/i I'dlitUxjin I'fijilntr, \H\f2. 



508 FUNGI IMPERFECT!. 

leaves of Mesjyilus {Eriobotrya) Jcqjoriica causing them to become 
spotted and to wither. The hyphae live in the epidermis, 
and form a stroma from which conidia are given off. 

F. tremulae Frank. Frank ^ gives this as the cause of a 
disease of the aspen {Poindus tremula). The leaves turn 
brown and fall, the shoots in consequence soon drying up. 
Conidia are developed on the surface of dead leaves and ger- 
minate on living leaves of aspen, producing a gerra-tube which, 
after forming an adhesion-disc, penetrates into the cavity of 
the epidermal cells. 

F. depressum B. et Br. is foiuul on living leaves of Angelica sylvestris. 
(Britain and U.S. America.) 

F. praecox Rabh. On living leaves of Tragopogon orientalis. 

F. sorghi Pass. On living leaves of Sorghum halepense. 

The ft;llo\ving are North American species : 

F. caryogenum Ell. et Langl. On leaves of C'arya olivaeformis. 

F. effusum Wint. On leaves of Carpinus americana. 

F. destruens Peck. On living Avena satioa. 

F. fasciculatum C et E. On leaves and stems of Euphorbia. 

Scolecotrichum. 

Mycelium greenish. Conidia oblong or oval, produced both 
terminally and laterally on the conidiophores. 

Scolecotrichum melophthorum (I'rill. et Del.).- This pro- 
duces a melon disease in France known liy the name " Nuile." 
It consists in the fruits and stems becoming spotted, the tissue 
being completely destroyed. 

Sc. graminis Fuck. Occurs on grasses, especially on the oat. 
PammeP reports it as also injurious on barley during 1891, 
in some parts of the United States : the diseased leaves were 
marked with brown or purplish brown spots. 

Sc. fraxini Pass. On living leaves of Frcurinus excelsior 
and F. Oiiias. 

Cladosporium. 

Mycelium greenish. Conidia globose or ovoid, one to four- 
celled, and of variable form. The species are mostly sapro- 
phytes on substrata of all kinds. 

^ Btr. d. deuUcli. hotan. Gtiell, 188.S, p. 29. 
- Bidletin de la nor. mycolorj. de France, 1891. 
" Jo^irnal of Mycolo(iy, vii., p. 96. 



(LADusi'uiurM. 509 

Cladosporium herbarum (Pers.). Tliis species is found every- 
where on dead plant remains, but it is also connnon on livini; 
leaves of many plants. The tirst suggestion that this form 
nnght occur as a parasite came from Haberlandt ^ and Frank." 
It possesses a dirty-grey, thick, septate mycelium, which may 
be colourless when young or growing inside a suljstratum ; it 
applies itself closely to the surface of plants and even pene- 
trates through the stomata or cell-walls into the tissues. Tlie 
conidiophores are erect, otherwise variable in form ; they give 
off conidia from the apex or from lateral processes. The 
conidia are oval and contain a variable number of cells. Organs 
of plants attacked show grey spots, and withered ]«arts if they 
are still alive. 

The following are some of the papers describing Cladosporium 
herbarum as, in certain circumstances, a parasite. Prillieux and 
Delacroix,^ on apple-trees and raspberry-bushes ; (.'avara,^ un 
raspberry, cycads, agave, and other plants ; Sorauer,' on peas. 
Ix)priore ^ describes this fungus as the cause of a " black " 
disease on ears of wheat : the results of infection were liowever 
somewhat variable. 

Kitzema Bos reports it as producing disease, and in some 
cases death, in fields of oats. Kosmahl and Xobbe " found 
that seedlings of Pinus rigida blackened and ilied suddenly in 
the beginning of May, apparently from the attacks uf this 
fungus. Janczewski" states that this Cladoaporium is a conidial 
form of Sjihiiinlhi Tula^iiiei, a new species of Ascomycele 
established by liini."' 

CI. elegans I'enz. Tiiis causes on tiie orange a disease or 
"scab/" whiili has Ix^en injurious lioth in SmUhern luirope anil 
the Southern States of America.'' It attacks chietly wild orange 

' Frii/i/iiiij's /ainlirirtli. ZiifiDi'j, 1S7S. 

■^JJi< KmnkheiO-u <l> r rflauz'ii, 'Jii.l l"Mit., 1S!»(!, ii., p. _".»_'. 

'^ BtdUtiii lie la nor. vnjroloij. df Frunr, , vii. 

* litnu- iiit/coloi/ifiiie, 1S!M. 

^ Ilaudliurh d. /'jlaitfitkraiikhi ifi n, lSS(j. 

'^liirirhtt d. d.ntxrh. hofnii. UimII, ISW ; Landwlrth. Jahrl>u>h, l«JM. 

' K.it rails du liidhlin dr rAcadnnie d,A sci. d> Cracori^, ISJh.'. ISJCJ, ISJU. 

•* S(.ho8takowit«ch (t'lani, 189.") (crg/.lul.) (li«tiiiguiMlif8 Clailonpurium from otlicr 

' .Scribiier, /iiifhlhi of Turn ;/ ('/iil>, Xlii.. l.SS(i, p. 1S|. I'ikIlmwiwhI, 7aii»-»m/ i./' 
My<i)lii<iy, VII., J). 'M. Swiiiglf iiiul Wfltlur, "UisuuMfa of ( itmuM KruiU," 
U.S.A. /)>j>(. (,/ A>in<nt/un lUdhliii M. iS'.Mi. 



510 FUNCxI IMPERFECTI. 

trees, more rarely the sweet orange and lemon. The disease 
first appears as whitish or cream-coloured spots on leaves, young- 
twigs, or fruit. If the spots are numerous the leaves become 
badly curled or twisted, and covered with wart-like eruptions. 

CI. viticolum Ces. is regarded as a dangerous parasite of the 
vine. 

CI. carpophilum Thiim. This species has been found para- 
sitic on plum and peach in the United States. Its mycelium 
creeps over the surface of leaves and fruit, causing pale-coloured 
spots which extend and run together, spoiling the appearance 
of the fruit. The disease as yet does not appear to have a very 
wide distribution, nor is it directly very injurious, but as 
cracking of the ripe fruit occurs when it is present, the way is 
opened for entrance of fruit-destroying fungi. 

CI. condylonema Pass, also occurs on leaves of the plum. 
It causes leaf-spot and leaf-curl. The mature conidia have 
fine spines on their coat. 

CI. fulvum Cooke. (Britain and U.S. America.) This is the 
cause of a disease of tomato. It attacks leaves and shoots of 
plants cultivated indoors, and soon causes their death. Prillieux 
and Delacroix ^ have described a somewhat similar disease in 
France, found, from artificial infection, to be produced by some 
species of Cladosporium, but whether this particular species, 
they did not state. 

CI. cucumerinum Ell. et Arth.- causes a disease of cucumber 
Frank ^ describes a disease which he found to be due to a 
Cladosporium {CI. cucumcris n. sp.). This attacked the fruit of 
both cucumbers and melons in cultivation under glass at Berlin, 
and caused great damage ; brown rotten depressions appeared 
on the fruits, and thereon the tufts of conidiophores. 

CI. macrocarpum Preus. causes a " scab " disease of spinach in 
the United States {N.J. Agric. Exikt. Station Bulletin, 70, 1890). 

Other species that may be parasitic are : 

CI. pisi fug. et Mace. On living pods of Pisum sativum in Italy. 
CI. epiphyllum Mart. On leaves of Quercus, Platanus, Populus, Hedera^ 
etc. (Britain and U.S. America.) 

CI. juglandinum Cooke. On leaves of the walnut. (Britain.) 

' Bulletin de la .wr. 77iyrolo<j. de France, 1891. 
-Description in Mass. Agric. Exper. Station Report, 1892. 
'' Ztitfichrift f. Pflanzenkrankhtittn, iii., 1893. 



CLADOSPOIUIM. 



'11 



CI. Scribneriamum Cav. ( )ii leaves of Betxda popuUfolia in America 
and Italy. 

CI. hypophyllum Fiiek. On leaves of Clmai rampcstris. 

CI. tuberum Cooke. lu the tubei-s of Batatas edulU in Carolina, U.S.A. 



3. Sect. Phragmosi'ur.\e. 
1. Sifbsect. Micronerivac. 

Clasterosporium. 

Conidia brownish, cyliiidriciil or spindle-shaped, and consisting 
of three or four cells. 

Clasterosporium amygdalearum (Pass.) attacks the leaves of 
almond, peach, apricot, cherry, and jihnii. An intercelhdar 
mycelinm has been fonnd, and roundish dry spots with reddish 
margins are formed. Thereon tufts of short conidiophores are 
developed, bearing cylindrical, thick-walled, pluricellular conidia. 

CI. glomerulosum Sacc. {Sporidcsmium glom. Sacc, 1878, and 
P/eospo/v roivjhitiaaia Goebel, 1879). Cloel»eP tirst described 
this species as a parasite on Junipems communis. A colourless 
intercellular mycelium is present, and in conseciuence the 
needles turn brown, die, and fall oil' 
prematurely. On the upper side of 
the needle the mycelium emerges 
through the stomata, and forms 
dark -grey coils from which the 
grey, ovoid, pluricellular conidia are 
given off. 

Ceratophorum. 

Conidia luow iiish, spindle-shaped 
or cylindrical, three or more celled, 
the upj>er ci'll witli tcrniinal 
blistlcs. 

C setosum Kirch. Dark spots occurring on the leaves, 
jjetittle.s, and .shoots of young plants of Ci/tisus Lain/ rn inn, etc., 
wt-rc foinid to enlarge and bring abo\it death and defoliation. 
J\iiiliiu'i found llir leaf-tissue permeated by a cojourlfss septate 
mycelium, which gives off conidia on bolli .sides of the leaf. 
The conidia resembled those of J\stif/oz:i(i, but their cell-number 

' W'urtetnhunj nnfunl•i^^l. Jahreitheftf, 1879. 
X'it^cliri/l }'. I'flaioukniidhtit'ii, IS'h.', |>. .f-M. 




Flti. 'iXZ.—Ctralophoi-uiii iHlotuui on 
Ci/tisM capitdtut. Lciif with diHcuutixl 
apices. An iiwjlntod iipuro wltli lu 
^IipcQciagcM. (After Kirchiiur.) 



512 FUNC4I IMPKRFECTI. 

was variable, and the terminal cells, although lighter than the 
median, were not quite hyaline. The terminal cell bore several 
very long bristles. 

C. ulmicolum E. et K. On living leaves of JJlmus fulva in 
America. 

Helminthosporium. 

Conidia brown, cylindrical or spindle-shaped, and pluricellular. 
Mycelium well-developed and brownish. 

" Distinguished from Clctdosporium by the conidia being more 
than one-septate at maturity " (Massee). 

Helminthosporium gramineum (Eabenh.) ^ This causes a 
disease on barley, both in Europe and the United States ; as yet, 
however, it is not very common. It attacks generally the lower 
leaves, producing long, narrow, dark-brown spots with yellow 
margins. The leaves so attacked gradually wither, but do not 
prejudice the yield of grain seriously. On the spots are 
developed the black septate conidiophores, each with a large 
black conidium with from two to eight cross-septa. 

H. turcicum Pass, causes long spots on the leaves of Zea mats 
both in Italy and America. The spots are yellow with indistinct 
dark margins, and from them arise patches of grey septate 
conidiophores. The conidia resemble those of the species last 
described, so that some authorities regard the two forms as one. 
Briosi and Cavara describe the mycelium as consisting of 
branched septate hyphae, the cells of which frequently become 
irregularly swollen. The young Indian corn leaves are killed, 
and the crop may, in consequence, be seriously injured. 

H. teres Sacc. This is a form of IT. gramineum which 
Briosi and Cavara distinguish as occurring on oats. Infection 
takes place at the apex of the leaves, and the mycelium spreads 
through the parenchyma causing elongated dry spots, so that 
the leaf ultimately dries up and dies. The conidiophores are 
developed singly, not in tufts, and the conidia are smaller than 
those of H. fjramineicm. The conidia are greenish, thick-walled, 
pluricellular, and produced terminally. 

H. gracile (Wallr.) causes long marginate spots on the leaves 
of Iris gcrmaiiica. 

'Eriksson, Botan. Centralhlatt, xxix., 1887. Kirchner, Zeif.schrift f. PJlanzen- 
krankheUm, i., 1891, p. 24. 



CKRCOSPOUA. 513 

Cercospora. 

Cunidia elongated and slender, olive-irreen, and septate. My- 
celium greenish. 

'' J)istinuuisli('(l liy the veiiniforni septate conidia " (Massee). 

Cercospora circumscissa Sace.^ This is a parasite which 
occurs on cultivated almond, peach, and nectarine, as well as 
on wild Frumis serotina in the United States. The leaves are 
attacked while still young, and exhibit by reflected light a 
yellowish spot with a dark centre. The conidia arise on the 
spots as dark-green clusters, thereafter the diseased tissue shrinks, 
becomes detached, and falls out, leaving " shot-holes " not 
unlike those produced by species of Phyllostida. Defoliation 
may occur in severe cases of attack. As a result of the 
injury to the foliage, the new wood does not mature well, 
and second growth may take place during the same season ; 
shoots of this kind will probably dry up during winter. The 
fungus may also directly kill the tissue of twigs as far as the 
cambium. The fruit is never attacked directly, but may be 
seriously affected through the injury to leaves or twigs. 

In order to minimize the disease, it is recommended to burn 
all fallen foliage, and to turn the earth thoroughly below infected 
trees. Pierce obtained a crown of very healthy foliage on almond 
trees treated with (1) ammoniacal solution of cojiper carbonate, 
and (2) modified eau celeste. 

C. persicae Sacc. On leaves of peach. (U.S. America.) 

C. acerina Hartig- appears on brown spots on the cotyledons, 
young leaves, and stalks of young plants of Aver. The conidia 
are grey, pluricellular, and slightly curved (Fig. 314). The 
mycelivmi inhaljits the intercellular spaces (tf the parts attacked, 
and forms resting .^clerotia in tlie tissues of dead leaves. 

C. viticola ((Jes.).'* This fungus is found in Mumpc and the 
I'nited States on VifU vinifrra and V. La/iriisiit. It causes 
spots on tlie leaves, and from these arise close columns of 
septate conidioiihorcs which give oil' thick pluricellular conidia. 

C. beticola Sacc.' inllicts considcralijc injury on cultivated 

' I'itrif, JdiiiihiI i>/ A/yiii/di/i/, vn., p. (><> iiinl |>. ■_'.'{'_'. 
'■* R. Hartig, Uiifeniitr/tiiiiiji u nits il. /or-'lhotriii. Instilul, I., Miiiiicli. 
•' DeBciiptioii mill treatiiKiit in A'*"' York- Aijrii-. h'j/>ri: Stntioii JiijMni u>i 
1M!»(», i». M-J4. 

''I'lnmuii, /Ji' lifkiiiiiiil'uiiti il. /'i/'.k/riid/n it'll iiii.s, n r Kiillitniruiir/mr, |H,S«5. 

L'K 



514 



FUNGI impp:rfecti. 



sugar beet and beet-root. It is easily recognized by the 
numerous sharply defined spots produced on the leaves. The 
conidia are very long and pluriseptate. In the United States 
this is one of the most serious of beet diseases.-^ As preventive 
treatment, great care should be taken to destroy all infected 
material. A long rotation should also prove a good remedy. 




Fig. 314. — Ctrcospora acciina. 2, Seedling of Acer, with a cotyledon brown and 
withered, and a leaf partially so. 4, Section through a diseased cotyledon ; the 
conidiophores (d) emerge from the epidermis, and bear long tapering septate 
conidia; (, sclerotia formed inside the diseased tissues for hibernation. 5, Ger- 
minating conidia. (After R. Hartig.) 

C. apii Fres. Common on celery {Apium graveolens) and par- 
snips {Pastinaca sativa) throughout all Europe and North America. 
It causes leaf-spots at first yellowish then enlarging and turn- 
ing brown. The mycelium grows in the intercellular spaces of 
the leaf, and gives off tufts of conidiophores through the 
stomata. The conidia are long, tapering, obclavate bodies with 
an attachment-scar at their larger end.- 

0. asparagi Sacc. occurs on asparagus in Italy ; C. caulicola 
Wint. frequents the same host in America. 

C. Bloxami B. et Br. On Brassica in Britain. 

C. armoraciae Sacc. On horse-radish. 

iPammel. loira Agric. Exper. Station B^dhtin, li5. 1891. 
'■^Description in Neiv Jersey Agric E.vper. Station Bulletin 2, 1S91. 



CERCOspoRA. ol5 

C. resedae Fuck.^ This fungus is the cause of a garden 
mignuneite disease very common in America and Eurtipe. It 
causes little depressed spots with brownisli or yellowish borders, 
which begin as reddish discolorations of the ]enf. The leaves 
gradually wither and dry up, so that the flowers suffer. The 
mycelium grows inside the leaves, and gives oH" tufts of conidio- 
phores through the stomata. The conidia are elongated, septate, 
and spindle-like or club-shaped. Spraying with 15i»rdeaux 
mixture was found to give good results. 

C. cheiranthi Sacc. produces roundish leaf-spots <»n wall- 
liowtT, and, if severe, causes death of tlie leaves and juenuiture 
<lefoliation of the plants. 

C. rosaecola Tass. This causes leaf-spot on cultivated and 
wild roses in the United States. The lirst indication of disease 
is the appearance of black spots with reddish margins. The 
conidiophores emerge from the stomata in tufts, and cany hmg 
obclavate conidia. 

C. angulata Wint. is one of the causes of leaf-spot on 
currant, and occurs often in company with S<pforiu rPns. (T.S. 
America.) 

C. violae Sure, occurs on leaves of Viol" odoratu. 

C. malvarum Saoc. On species of Malca. 

C. althaeina Sacc. On hoUyliock in the United States. 

C. neriella .Sacc. causes leaf-spot on Xerimn Olennder. 

C. Bolieana (Thlini.) ])roduces olive-lnown spots on It-avcs ami truit-i 
<jf tlif Fi'_r, iiiJMiini,' the crop. 

C capparidis Sacc. On Cupparis spinOK'i in Italy. 

C. gossypina Cooke is given by Atkinson as a fungus fiecpicntly iiresent 
oil diseased plants of cotton. - 

."^accardo records over 230 species of Cerrospora, most of whiih lause 
spotting of living or fading leaves of many plants, e.g. I'Iiusi-dIuh, Lupiiiii.<, 
Trifoliam, Vicia, (jh'dittrhia, Solannm niyrum. Datura, Iticiniis, AinpflopniK, 
Liriuilendron, Tilin, Rosa, PottuUilla, KahuM, (.'//(/vtiia, /'teha, Uliainuiin, 
h!uony)nus, Ailnnthus, IIIihh, Santbitcus, Vilmrninii, (Ufa, Si/ringa, Munt«, 
Frcurinwi, Voffea, Lignstriim, ilercnrialis, etc. 

Heterosporium 
< 'oniiliophores simph- oi branched. ('t)nidia njive, nblong, 
|>hiiist'pt;ite, and witli a spiny or warty outer coat. 

' K.iir.hil.l in U> port i>/ Sirfi„u ,,/ \'..i>hil,/, I'atlmlojy fur iSSil, I'.S. I>fpt. 
of .Aj^riciiiture. 

- Jtofniiiral d'n'rth', |S!I|, \>. lil. 



516 FUNGI IMPERrECTI. 

"Resembling HdviinfJio.^porium in general habit and structure, 
in fact only distinguished by the minutely warted conidia " 
(Massee). 

Heterosporium echinulatum (Berk.).^ (Britain and U.S. 
America.) The '"fairy ring spot" of Carnations. This is a 
serious enemy of cultivated carnations, and causes great damage. 
It was first described by Berkeley in 1870 as a carnation pest. 
The symptoms are light-coloured spots on which are concentric 
rings of dark-coloured conidiophores. These arise from dark- 
coloured portions of the mycelium inside the leaf and give off 
conidia wnth three or more cells. The conidia are at first 
terminal, l)ut after one has been formed the conidiophore 
branches laterally and produces another conidium, repeating this 
process for a considerable time. The spots are produced on 
leaves, leaf-stalks, and sepals, causing them to wither. In 
consequence the flowers do not unfold and the plants are 
rendered unsightly. 

Cultivation of the carnation in dry airy conditions is said 
to keep this disease in check. 

The following are British species occurring generally on 
fading leaves : 

H. variabile ( 'ooke. On spinach. 

H. ornithogali Klotzsch. On Ornithogalum, Convallaria, and other 
species of Liliaceae. 

H. typharum C. et M. On Typha angtistifolia. 

H. laricis C. et M. On larch needles. 

H. asperatum Massee.''^ Occurs as a parasite on Smilacina stellata. 

Napicladium. 

Conidia oblong, three or more celled, and produced singly 
on the end of short conidiophores. 

" Somewhat resembling Hdminthosiwrivm and Bracliysporium, 
but distinguished by the less rigid fertile hyphae and the 
large solitary conidia " (Massee). 

Napicladium (Helminthosporium) arundinaceum (Cord.). 
(Britain.) This lives parasitic on the leaves of Pliragmitcs 
comrmmis, and spreads rapidly from plant to plant. The leaves 

1 Worth. G. Smith, Gardener's Chronicle, xxvi., 1886, p. 244. 
Atkinson, ^^ Carnation Diseases" at American Carnation Society, 1893. 
• ^Massee, American Journal of Microscopy. Fehruary, 1S9.S. 



NAl'ICLADILM. 517 

become coated with coiiidia and assume a leaden .i,'rey colour, 
so that in many cases only the points remain «,'reen. Finally 
the attacked leaves die and diy u}*. 



4. Sect. Dictyosporak. 

1. Subiie<:f. Micrniiemi'ae, 

The forms included under genera of this L,'roui» (e.g. Sporu- 
dtamium and Coniothecium) have as yet been littK- investi<'ated 
in regard to their parasitic nature. 

2. Suhsect, Macronemeae. 

Macrosporium. 

Conidia grey, muriforni, and Nome on tlie a))ex of simple or 
Itranclied conidio[)hores. 

Macrosporium sarcinaeforme Cav.^ Cavara ilescribes a 
browning and death of a wliole tield of red clover {Trifoluim 
prutcnsr), and ascribes it to this fungus. ^linute spots were 
produced, at first light-coloured, tlieu brown, Hnally coalescing 
so as to cause drying-up of the whole leaf. The sliort thick 
conidiophores were develo))ed on the lower surface of the leaf, 
and gave off jiluricellular terminal conidia. 

M. solani Ell. et Mart. This is described- as occurring along 
with the •• hhick-rot " of the tomato in the Ignited States. It is 
said to cause a rot in the fruit and a leaf-blight on both tomato 
and potato. Along with this sjieeies there also occur a Fnsdiiinn 
(p. oL'O) and frequently a ('/(((/(>sj)i,,-iui/i ; as yet the relationship.s 
of the different forms, and the ))art they take in causing the 
diseases ascribed to them, is but im])erfectly investigateil. 

Sorauer'* ascribes a disease un tlie ])utato in (lermany to tids 
species or to an Altinuiria {A. solani). He also l)elieves that 
it is tht; cause of the "early blight" of Ameiican potato crops, 
but further investigation is still reipiired. 

Many oilier species of Macrosporiinn have been described on 
jihmts of economic importance, yet most of them occur oidy on 
j)arts S(jmevvhiil faded or languid, so that they caniiol be regardeil 

' Hrioni mill Caviira, Fiiinj/ii /inrnsif., v. 

■Ji'^jitiif »/ llf Sirtion III' I'liji till,/. I'dllinltxiy /i>r ISSS. f.S. I )i |iartin«lit of 
Agricultiiiu. 

■ Z' i/srftriff J. I'jlnir.iiik-rmikhiit' II, IS'.Mi, p. I. 



518 FUNGI IMPERFECTI. 

as important parasites. Amongst these are the following British 
and North American species : 

M. brassicae FJerk. On cabbage, generally somewhat decayed. 

M. sarcinula Berk. On encumber. 

M. nobile Vize. On Dianthus. 

M. alliorum Cke. et Mass. On onion. 

M. ramulosum Sacc. On celery. 

M. catalpae Ell. et Mart. On CataJpa Bignonioides. 

M. nigricantium Atks. is a semi-parasite accompanying other diseases 
of the cotton plant. 

Mystrosporium. 

" Allied to Macrosporium, but distinguished by the more rigid 
and darker-coloured hyphae and conidia " (Massee). 

Mystrosporium abrodens Neumann.^ This is described as 
the cause of a disease which destroyed one-tenth of the total 
wheat-crop in the Haute-Garonne of France. The fungus 
attacked the nodes and leaves, forming dark patches ; the nodes 
were weakened and frequently broke over, while the ears were 
badly developed. 

Alternaria. 

Conidia grey, muriform-septate, flask-shaped, and borne on 
short simple conidiophores. 

" Distinguished by the clavate or flask-sliaped muriformly 
septate olive conidia being united in chains and connected 
by narrow isthmus-like portions " (Massee). 

Alternaria brassicae (Berk.) (Britain). This species causes 
on leaves roundish black spots marked with concentric lirown 
zones. The mycelium lives in the leaf- parenchyma and gives 
off tufts of conidiophores through the stomata. Briosi and 
Cavara state that it causes considerable damage to Brassica 
oleracea, Cochlearia officinalis, and Armoracia. (Probably the 
same species as Polydesmus exitiosv.s Kuhn.) 

Other diseases have been ascribed to species of Altcriuiria. 

Septosporium. 

Conidia brown, and muriform-septate. Conidiophores of two 
kinds — short and fertile, or elongated and sterile. 

Septosporium heterosporum Ell. et CJall. causes a leaf- 

' " Uu noiueaii parasite de bk-."' Societc dt Biolofj. a Toidoii-se, 189'2. 



sp:PT0SP0KirM. 519 

spot on Vifis calif ornica in California. The leaves become 
quite black on the lower surface, brown un the upper. The 
fungus has not as vet been reported on cultivated vines. 

Fumago. 
Conidia grey and two- or three-celled. 
The species belong to Ciipnodium (see p. ISl). 

3. FAM. STILBEAE. 

1. SeR. HVALOSTILBKAE. 

Sect. A merosporae. 

Stysanus. 

Conidia pale-coloured, more or less spherical, and developed 
on a dark cylindrical or clavate erect stroma. 

Stysanus veronicae Pass.^ This produces irregular spots on 
the k'a\t'.s (if cukiviiied Vrronicd lonijifolia in Italy, and causes 
the plant to wither. The euhunnar stromata are produced on 
the lowtn- surface of the leaves, and give oft' unicellular c(jnidia. 

St. ulmariae M'W.- On Spina Ulmariu in Ireland. 

Isaria. 

Stroma erect, clavate, generally branched and bearing Lcuidin- 
phores all over. The conidia are abjointed from the apex nf 
the (•(iiiididphores, and are unicellular, hyaline, and rounded. 

Isaria fuciformis lierk.^ This disease, first ob.served in 
Au.stralia, is described liy Smitli as occurring in England. It 
attacks grasses, especially Fistura, during summer. The stems 
and ears are glued together by the fungus-strtmia, and conidia 
are developed on all parts of tlie plants. 

•2. Ski:. I'ii.vko.stii.hk.ve. 
Serf. Fli rai/inos/xirue. 

Isariopsis. 

('onidiii palc-(,T)li.ured, (-ylindiical, and iijuricfllulai-. 
Isariopsis griseola Sacc^ pmdiues spots (tn leaves ni living 

' JI,ilirl<iia, 1S77, p. I •_'.•{. 

-M'Weeney, Jrish \(i/iirn/isf, 18i(."), ]>. -.'TH. 

•'Worth. C Siiiitli, />ii(<»ws 0/ Fi'ld ami (Innhn l'n>i>'<, LoikIi.ii, |ss4. j. .m. 

■* IJrioHi aii<l (';iviir;i, Fiiiii/hi ixiraiit. 



520 FUNGI IMPERFECTI. 

cultivated kidney bean. The mycelium lives in the leaf-tissues 
and forms stromata under the stomata, from which the conidio- 
phores arise in tufts. The fungus often occurs along with 
Uromyces 'jjhascoli. 

Other species of Isariopsis are recorded on the living leaves 
of various host-plants, e.g. Gcrastium and SteUaria. 

4. FAM. TUBERCULARIEAE. 

Volutella. 

The conidial patch or sporodochium is disciform, regular, 
and fringed, or studded over with elongated spine-like hyphae. 
Conidiophores simple or branched, and bearing elliptical or 
oblong conidia. 

The majority of the species of Volutella frequent only dead 
plant remains. Atkinson,^ however, describes and figures a 
widespread carnation-disease in North America, which is ascribed 
to a species as yet unnamed. Fresh cuttings are most commonly 
attacked, and exhibit dirty brown depressed areas, which soon 
ruin the cutting for purposes of cultivation. 

Fusarium. 

Sporodochium more or less effused. Conidia spindle-shaped 
or sickle-like, pluricellular when mature. The conidiophores 
are branched, and give off the conidia from their apex. 

Fusarium heterosporium Nees. Frank - found a field of 
rye near Kiel completely destroyed, and the ears quite over- 
grown by this fungus. I have found it on ears of Lolium 
perenne and Molinia cocrvlea in Bavaria. 

Species of Fusarium have been frequently described as causing 
injury to cereal and grass-crops,^ in some cases to a serious 
extent. 

While most of the species of Fusarium are found only on 
dead or dying plant-remains, a parasitic mode of life has been 
ascribed to some. 

Fusarium lycopersici Sacc.^ The " Sleeping Disease " of 

^ " Carnation. Dineaaes" in Keport of American Carnation Society, 1893. 
'^Jahrbuch d. deutsch. landioirth. GeselL, 1892. 
■'Worth. G. Smith, Diseams of Crops, 1884, p. 208. 

Rostrup (Fusarium avenaceum on Oat) Landboshrifter, v., 1893. 
^Massee, Gardener's Chronicle, xvii., 1895, p. 707. (Edit.) 



KL'SAKllM. 521 

tomatoes. This tomato disease has proved very destructive 
during recent years in liritain, particularly in the Isle of 
Wight and the Channel Islands. Plants are attacked when 
quite young, but the disease seldom manifests itself outwardly 
till the plant is full grown. The first symptom of disea.se 
is drooping of the leaves, with or without discoloration. At 
this stage the roots of attacked plants will be found to have a 
yellowish brown colour in the wood region. The mycelium 
of this fungus will be found in the vessels and other elements 
of the root. They are believed to originate from resting-spores 
which have hibernated in the soil and given off germ-tubes l)y 
which young rootlets were infected. The mycelium makes its 
way up the tomato stem, discolouring the vascular bundles as it 
goes. The conidia are produced on all diseased organs as a 
whitish bloom on the epidermis. The earlier conidia (I)iplo- 
chidium) are oval and one- or two-celled, but they are soon 
replaced by pale orange crescent-shaped conidia of the true 
Fusariinn type. The resting-spores are produced on the hyphae 
in the tissues of the decaying host-stem ; after hibernation, they 
germinate and produce hy])hae which give off the Diploiladiuin 
stage. Masses f(jund tliat only the germ-tubes from resting- 
spores were al)le to infect tomato planta The same author 
does not consider fungicides of much avail on account of the 
disease beginning from the roots. Careful removal and destruc- 
tion of all infected material, and a liberal appliiatii>n ^^'i lime 
to the soil are measures recommended. 

Fus. limonis r.iinsi {Fusisporium limoni-i Hriosi). This is 
given b\' P>rii)si as the cause of " mal-di-gomma " of uraui^e 
and lemon trees in Italy and elsewhere/ Webber and Sw ingle - 
ascribe the disease of tlie orange and leiunn in Flniida knnwn 
as " foot- rot " t(j the same fungus. In Florida the damage done 
is great and much more serious than that causi'd by any other 
disease of the same plants. It may be recognized by ihe 
exudation of gum fidin patches near tiie base of the tree. Tlu' 
patches enlarge and the disease spreads round the trunk aiul 
downwards into the roots, passing inwards from bark to eandmim 
and Wood, kiljinu' the tissues as it g(jes. Other syMiptoms 

' BrioHi, " Mul ili goiniiia," Mnnofin dilln H. Aind. i/i i Liiicri, Uuiiie, lS~H. 

- WeMxr ami Swingle, " KiHcii.sca of citroiiH fruits in Floiida." i'.S. Amrrim 
Jh/>f. of A'jrlrit/tnn liulhiiii, N... M, iS'.Ki. (K.lit.) 



522 FUNGI IMPERFECTI, 

are sparse foliage, small yellowish leaves, and death of the 
smaller branches over the tree. Sweet seedling orange {Citrus 
avrantium) and lemon {C. livionum) are most subject to this 
malady, the grape-fruit (C. decumana) is only slightly liable, 
and the sour orange {C. higaradia) is almost wholly exempt. 
For this reason sour orange stocks should be used on lowlands 
and flatwoods, and grape-fruit stocks on the higher lands. The 
most efi'ective treatment is to remove the soil around the crown 
roots by using a jet of water. Diseased bark should also be 
cut away and the wounds painted over with carbolic acid or 
sulphur wash. Good drainage to promote root aeration and 
the avoidance of excessive use of nitrogenous manures are also 
recommended. 

Fus. vasinfectum Atks.^ A species found by Atkinson to 
cause a cotton-disease known as " frenching." This consists in 
a discoloration of the leaf from the margins inwards, at first 
pale or yellow, but turning to brown. A mycelium was found 
in the tissues of the stem, causing the vascular bundles to 
assume a light brown colour. The host-plants are either killed 
or so seriously affected that the crop is injured. The conidia 
formed are of the pleuriseptate slightly curved Fvsarium type. 

Atkinson - in the course of his investigations on carnation 
diseases found a Fusarium present in all cases of the " carnation 
rosette." The stems remain short and stunted with their leaves 
small and crowded together. A mycelium was present in the 
tissues of the stem and caused discoloured spots. 



II. THE PATHOGENIC SLIME-FUNGI. 

MYXOMYCETES. 

The Myxomycetes ^ rank amongst the lowest of plant-forms. 

They show so close relationship to the lowest animals that 

certain groups {Monadind) receive greater consideration from 

the zoologist than from the botanist. They exhibit in their 

^Atkinson, "Cotton Diseases," Alabama Ag7'ic. Exjxr. Station BuUetin, No. 
41, 1892. (Edit.) 

-'■''Carnation Diseases" at American Carnation Society, 1893. 

•*The more important literature dealing with this family will be found in: 
De Bary, Morphology and Biology of the Fvngi (English Edition) ; Lister, The 
Myretozoa, London, 1895 ; Zopf in 8chenk's Handhuch der Botanik, ill., 1887 j 
Schroeter, "Myxomycetes" in Die natilrlirh. Pflanzenfainilien , i., 1892. 



THE PATHOGENIC SLIME-FIN(;1. 523 

mode of reproduction a close reseniblanee to the Fungi, and as 
a result of their lack of chlorophyll, they share with Bac- 
teria and Fungi the peculiarities of saprophytic and parasitic 
nutrition. 

The vegetative body of the Slime-fungi consists of naked 
protoplasm without a firm membrane. Multiplication is cHected 
chietly by spherical spores with the same external appearance 
as the usual fungus-spore. Immediately on reaching maturity 
the spores germinate in water and burst, setting free a mass of 
plasma provided with a nucleus and vacuoles, and in which an 
outer movable hyaloplasma can be distinguished from an enclosed 
granular plasma. The hyaloplasma gives off delicate pseudopodia 
capable of extension and retraction, it may also take the form 
of a tlagellum or of cilia. The organism is enabled by means 
of the pseudopodia to creep over firm objects as an " amoeba " ; 
by the cilia it can propel itself through water, as a " swarmer " 
or "zoospore." A zoospore in the course of its development 
generally loses its cilia and becomes an amoeba, and both 
forms can multiply by division. The amoebae creep together 
in large numbers, and either coalesce completely into masses, 
oT remain simply in contact as aggregations. In tliis way 
Plasmodia are formed, frequently of considerable size and of 
conspicuous colour. The plasmodia maintain a constant move- 
ment, both as a whole and in the form of internal streamings. 
Ifesting stages have been observed at each motile stage of 
the life-history ; thus swarm-spores rest as microcysts, young 
Plasmodia as thick-walled cysts, and mature ]»lasmodia as multi- 
cellular sclerotia. 

Multiplication of the ^lyxomycetes also takes phice by spon- 
formation. In the Acrasieae and Phytomyxinae tiie spores are 
developed freely from the plasma. Tiie Kxosporeae, a very 
small division, lia\f their spores deveh^ped on the outside 
of sporophores. In the greater number (Endosporcae) the 
spfjres are formed in special enclosures, which may be a spor- 
angium produced from u single jilasmodium, or an aethalium — a 
cushion-like structure consisting of numiiuus imperfectly defineil 
sporangia. 1'he sporangia are often of cnnsidenible size, some- 
times not uidike the sporocarjis of the ( lasteromyeetes, splierieal 
or jn-ar-shaped and stalked. Spdrangia of this liighly developt>d 
kiml iiiav t^ven exiiibit a certain (litleicntiatinn iutu a wall or 



524 THE PATHOGENIC SLIME-FUNGI. 

rind of compact plasma enclosing the spores, and frequently a 
supporting skeleton or capillitium is present consisting of 
numerous filaments of hardened plasma. 

Schroeter divides the Myxomycetes into three divisions, the 
Acrasieae, Phytomyxinae, and Myxogasteres (including the Exos- 
poreae and Endosporeae). Parasitic forms occur only in the 
second of these groups. If, however, all the forms included 
by Zopf in his group of Mycetozoa be taken into account 
many of them will be found to act as parasites and to cause 
frequent epidemics amongst algae and lower fungi. 

We shall here consider only the genera Plasmodiophora, 
Tetramyxa, and Sorosphacra. The genus Phytomy.ca of Schroeter, 
containing those micro-organisms which cause the root-tubercles 
of Leguminosae, has already been considered in our general 
part (see p. 101). 

Plasmodiophora. 

Spores spherical and developed inside the host-cells. This 
genus causes diseases of ccmsiderable economic importance. 

Plasmodiophora brassicae Wor.^ This species attacks all 
kinds of cabbage, kale, turnip, kohl rabi, and other varieties of 
Brassica Rcvpa, B. Napus, B. oleracca, and other edible Cruciferae; 
also other plants from the same order, such as Iberis umbcllata, 
Capsella hursa-pastoris, Mathiola incana, etc. 

The symptoms of the disease are manifold swelling, out- 
growth, and branching of the roots at all stages of growth, 
with a more or less marked stunting of the foliage, according 
to the season of attack (Fig. 315). The forms assumed by 
deformed roots are very variable and have gained the disease 
many designations. In ]:'>ritain it is known as " finger and 
toe disease," " club-root," " clubbing," and " anbury " ; in Bel- 
gium as " maladie digitoire " or " Vingerziekte " ; in Germany 
as "Ivropf" or " Kohlhernie." 

The disease was first recorded in Scotland about 1789, but 
now it has a very wide distribution, appearing in all places 
wliere cabbage, turnips, and allied vegetables are cultivated on 
a large scale. The roots after swelling become rotten and 

1 Woronin, PriiKj.-iheim's Jahrbnch, xi. , 1878, p. 548. Eycleshymer {Journal, 
of Mycolof/y, vii., p. 79) gives a good account of its distribution in America. 
Massee, Transact ion fi of Boyal Society of London, LVii., 189.1. 



PLA.SMuDRtl'lIOKA. 



OL'O 



decay, so that not only is the root itself worthless, but the 
aerial shoot is badly developed. The destruction is greatly 
favoured by moist rainy years. 

The malformations of the root are the result of hypertrophy 
of the host-cells due to a stimulus exerted by the plasniodiuni 
of Plasmodi&phora , not only on the contents of cells inhabited 
by it, but also extending into the cells of the whole neigli- 
bouring tissue. The cells so inilnenced enlar^i*' in size and 




Kiij. ;il6. — flasmoiiiophofa Itriuiiirae. Effcuta uii 'i'iirnii>» gmwii in f^cutluiia. 
(v. Tubcvif phot.) 



become divided iij) by new cidl-walls. Tin- plasiiKMljuiu niakt-^ 
its way frdiu cfll to cell by means of the wall-j)its, and 
by aljsorbing the contents it gvow.s and tills ihe whnle cell. 
( )n exhaustion of foud, and without previous enclosure in a 
luenibrane, the jilasmodiuin tonus itself into sjtores. so that the 
tissues of attacked roots become completely tilled with thick- 
walled s])ores, which are set free; only after decay of the 
surrounding tissues and eell-iueinliranes. The spores hibernate. 
anil in spriiiL,' inyxanioebae sli]i out, capable .if iidccling 



526 



THE PATHOGENIC SLIME-FUNGI. 



young roots of newly germinated cabbage, turnips, etc. They 
do this by penetrating the cell-wall, probably that of a hair 
to begin with, and the malformation ensues. The myxamoebae 
possess a tiagellum and pseudopodia, so that they are j&tted for 




Fig. 316. — Plasmodiophora brassicae. Effects on Turnip gi-own in Russia. 
(After Woronin.) 



different modes of locomotion. When entrance into a host-cell 
has been effected, a plasmodium is formed and growth proceeds 
as just described. 

Wakker^ describes, an enlargement of the attacked cells 
and an irregular growth of the roots, associated with a rudi- 

^ Pringsheim's Jahrbuch, 1892. 



PLASM(JD1»)1'HUKA. 



OL'7 



mentary condition and twisted course of the vessels, and an 
accumulation of transitory starch in the tissues. 

[The methods at our disposal for combatini,' this parasite all 
work indirectly. Its spores seem to retain their vitality for two, 
three, or more years, hence one very evident measure is not to 
plant the same crop in succession on land which has been attacked. 
As, however, all Cruciferae are liable to injury from this source. 




Flfi. 317. — I'latiitodioi'liOi-a br 



■III on Tiiiiiii). (.Vflcr WMiouin.) 



neither would it be advisable to h't say, turnips fttjlow 
cabbai^fe ttr kohl rabi on infected laml. For the same rrason 
weeds belon<(in^' to the ordri- ( "iiicirerae should not be allnwcd 
to (obtain a fo()tin;4 near land where plants liable to " liiiLji-r and 
toe" are under cultivation. In Scothmd, where turnips an* 
necessary in all eroii-rotatioiis, a four-year rotation does not 
^ive cfiinplete exemption from ibis disease, nor is live years 



528 



THE PATHOGENIC SLIME-FUNGI. 



considered quite a safe interval, but seven years is, and with 
good management the disease, though by no means uncommon, 
only then attains serious dimensions in moist seasons. Massee 
points out that the development of the fungus is favoured by 
acids and checked by alkalis ; this explains the well-known 
beneficial effects of dressings of lime or potash in keeping the 
disease in check. With a six or seven-year rotation, and the 
application of lime once in the rotation, the disease should 




Fig. 318.— Hypertrophied cells from a Cabbage-root attacked by Plasmodiophora 
brassicae. Several of the cells are filled with spores, (v. Tubeuf del.) 



never be very injurious. The direct application of farmyard 
manure to the turnip crop should also be avoided, especially 
if the stock which made the manure was fed on diseased turnips ; 
this is necessary because it has been found that the spores are 
not killed when eaten by animals.] (Edit.) 

Plasmodiophora vitis Yiala et Sauv.^ This is said to 
cause a Vine disease known as " Brunissure," which within 
recent years has caused considerable loss in France, North 
America, and Soutliern Paissia.^ The early symptoms are light- 
brown star-shaped spots on the upper surface of the leaves 
between the ribs. The spots enlarge and cause a premature fall 
of the leaf, whereby the grapes are prevented from maturing. 

1 Viala et Sauvageau, Compl. rend., cxiv., 1892. 

^Cooke [Garde.ney.'i Chronide, 1893) refers swellings found by him on roots of 
the vine in England to the action of this fungus. (P]dit.) 



I'LASMUDIUI'IIUIIA. 52y 

The above-named investigators found plasniodia in various stages 
of development in the palisade cells, and later in the spongy 
parenchyma of diseased leaves. On treatment with " eau de 
javelle " the plasmodia remained visible, whereas the contents 
of healthy cells disappeared. Spore-formati(tn has not as yet 
been observed. The same parasite has been seen in vines in 
the IJhine district. 

llecently Debray and lUive^ have, in consequence of their 
researches on Brunissure, removed the fungus from the genus 
Plasmodiophorn, and founded for it a new group Psriulocoinmi^, 
with a position near Vampyrella and Myxomycetes. This same 
fungus they also found in a large number of plants from thirty 
ditl'erent natural orders. 

Plasmodiophora californica \'iala et Sauv.- is another vine 
parasite which causes greater damage than the preceding species, 
lieddisli leaf-spots are produced, and extend so rapidly that the 
leaves may drop early in spring. The parasite also affects the 
shoots to such a degree that an abnormal nundjer of shortened 
Itranches are developed, the wood of which exhiliits brown 
stripes in autumn. 

It has not as yet been quite provetl that the plasma observed 
in withered vine leaves really consists of plasmodia of the 
al)ove two species of Plasmodiophora, nor have spores been 
found. The true cause of tlie diseases has proliably still to be 
explained. 

In cases of root-deforniatiou in jx-ar, Muller-Thurgau-' observed 
a .slime-fungus in cells of the root-parenchyma. 

Tetramyxa. 

Spores united four together as tetrads and enclosed in a 
delicah' iiK'inbrane. 

Tetramyxa parasitica (ioeb.' First found by (loebel in 
ditches of marshy meadows, causing tuberous lialls of a whitish- 
green to brown colour on leaves, llowers, and stalks of Jiiij>/>ia 
riistilliitii. Sections of the swellings showed the parenehyma 
to b(i divisibb' into a dark lirown (jriilral pai'l consisting of 

' CWi///. rciuln., (X.\., 189.")-, ami " l.<i lintnisHun," lirrtte dt I'iticu/titrt , ISUS. 
• Coin/jt. rtnil., <xv., 18(1*2, p. (iT. 
■'Jahri/iherirht il. I'em.S/nt. WiKlmntciil , II. 
M;()el)il, Flora, 1SS4. Mt-iiti(it<l in SicptliUi.l l.y I'mf. 'I'r.iil. 

•J I. 



530 THE PATHOGENIC SLIME-FUNGI. 

killed cells, and a lighter coloured peripheral part. The cells 
of young tubercles contain multinuclear plasniodia, which at the 
time of spore -formation break up into portions round each 
nucleus (spore-mother cells). These portions then divide into 
four spores, each with a nucleus. The spores remain enclosed 
in a delicate membrane as spore-tetrads, the characteristic feature 
of this species. The upper part of leaves containing galls 
frequently died. 

Sorosphaera. 

Spores enclosed in large numbers in a delicate membrane, 
and forming a single layer round a central cavity. 

Sorosphaera veronicae Schroet.^ causes quill-like outgrowths 
and malformations in the stems and leaf-petioles of species of 
Veronica ( V. hcdcrifolia, V. triplujlla, V. chamaedrys). The galls 
consist of enlarged parenchymatous cells containing numerous 
spherical or elliptical light-brown balls about 15 or 22^ broad. 
The balls are enclosed in very delicate membranes, and consist 
of a single layer of spores surrounding a small cavity. The in- 
dividual spores are elliptical or oblong in shape, about 8-9 /x 
long and 4-4" 5 /x broad. 



III. THE PATH(3GENIC BACTEEIA. 
SCHIZOMYCETES, 

Although the bacteria and allied forms included in this 
group are the cause of many diseases of mankind and of 
warm-blooded animals, yet very few diseases of plants are 
ascribed to their agency. ' The true Fungi, on the other hand, 
which we have seen to cause so many diseases amongst plants, 
only very rarely appear as enemies of the higher animals. The 
few cases in which bacteria have been stated to cause injury 
to plants are all as yet incompletely investigated and uncertain 
in two re.spects. Thus although a plant-disease undoubtedly 
exists accompanied by the appearance of bacteria, these bacteria 
may not be the cause of the disease ; nor need it follow 
that the phenomena accompanying an attack l^y bacteria are 
necessarily symptoms of disease. On this account we shall 

1 Schroeter, Emjler-Prantl nalilHich. J'JIanzen/amilien. 



THE PATlRiUENH: liA( TKlllA. 531 

consider those phenomena, which have been described as 
bacterial diseases of plants, very brieHy and with a certain 
reserve. This part of the work has been considerably facilitated 
by the use of Ludwijj;'s compilation of bacterial diseases,^ and by 
Migula's account of them from the bacteriolo-^icial point of view. 

Migula considers that only live diseases of plants have been 
<lefinitely proved to be due to bacteria, namely, pear or apple 
I)light, sorgluim blight, the bacterial disease of the niaize, the 
bulb-rot of hyacinths, and the wet-rot of potatoes. We shall, 
however, indicate briefly some other plant diseases which are 
suspected to have a bacterial origin. The slime-Huxes of trees 
have been already considered along with the genus Eiulomijces 
(p. 141), so that we om\t them here. 

Pear and Apple Blight. 

This destructive disease of the apple and jjcar in Xurth 
America has been proved by the investigations of JUirrill - 
and Arthur to be, without doubt, of bacterial origin. The 
disea.se has been known for over 100 years, and occurs 
with disastrous effects on fruit-trees in the orchards, as well 
as on crabs and other wild species. Pear trees seem to sutler 
most in the Eastern States, apple trees in Iowa and elsewhere, 
wiiile none of the species of Pi/rHS, Cijdonia, and Sorlm.^ are 
<,'.xempt from attack. 

The disease appears first on tiie burk as little dead spots; 
these, however, rapidly enlarge till death of twigs, branches, and 
even stems may follow. As a result of death of twigs, the 
leaves turn l)rown and fall, while a dark lluid exudes from the 
diseased bark. The presence of Itactcria has been }»rov(.'d in 
this exuded .saj) as well as inside the cells, and infections have 
been successfully carried out from pure cultures. Tiic name 
Micrococcus amylomrouH was given by I'.iiirill to (he organism. 
It flourishes on the sour umipc fruit, and in tin- tis.sufs of 

' L' lirhiirfi ilf-r iiitilfrKH Kry/t/oi/dint ii, 1S!('J. 
Mi^jiilii, Kritinrhe Uthertikht d. I'tlan-i nkvankhi ili n <lnrch liakt»rku rmtr- 
iff/i/, |H',)-_'. 

I'rillieux et Delacroix. " MiiliuUes baccillaircs." ('ninjifes rtntlii, IS'.M. 

- Bunill, Tht Amn-iran Xuturn/k/, ISSI. 

.\rtliur, III iiort of Xmr York- A'jrir. Ej.-jiii: S/dtioii, \HH~. 

W'iiitf, Ymihook of U.S. Ih/it, ui' A<iiiiii/tiin , iSll.'i ; <It»i i iption aiui 
treatment. 



532 THP^ PATHOGENIC BACTERIA. 

diseased branches, and is one of those forms which does not 
liquefy gelatine. One characteristic reaction is, that as destruc- 
tion of the tree-rind proceeds, fermentation takes place with 
production of carbon dioxide, hydrogen, butyric acid, and alcohol. 
The bacterial colonies should be carefidly cut out when 
detected. 

Bacteriosis of Carnations. 

Arthur and Bolley have recently described a bacterial dis- 
ease of carnations common in North America.^ It attacks the 
leaves almost exclusively, causing pale spots which later become 
whitish depressed areas. The plants are seldom killed outright 
and the leaves remain attached, but they are stunted in size, 
and the yield of flowers is prejudiced. The disease is favoured 
by poor cultivation in moist surroundings, and is more prevalent 
indoors. A very efficient remedy is to avoid watering the 
foliage, except at long intervals ; by means of wire-netting it is 
possible to water the roots without touching the foliage. (Edit.) 

Twig-galls of the Olive" (" Eogna or Loupe "). 

Twigs of the olive are frequently beset with knots varying 
from the size of peas to that of hazel-nuts. These consist 
chiefly of parenchyma which begins to decay internally before 
the gall has ceased growing ; finally the gall also dies. In this 
way cavities in the twigs are formed in w^hich Prillieux found 
large masses of bacteria (Bacillvs oleae), to whose action he 
ascribes the formation of the galls, as well as the decay of the 
tissues. Infection from pure cultures is yet required to show 
whether the galls are really due to the action of the bacteria, 
and whether the above-mentioned Bacillus is the real cause. 
I had the opportunity of personally inspecting the disease on 
olives near Eiva, and found that the galls really contained 
nests of bacteria, while death of twigs above the galls was 
very frequent. 

Similar symptoms of disease occur on willow, birch, pine,^ 
and other trees, but they have not been investigated. 

^Arthur and Bolley, Purdue UnirevHity Ayric. Exper. Stafio7i, Bull., 59, 1896. 

-Prillieux, " Les' tumeurs bacilles de I'Olivier, etc.," Revue gener. de 
hotanique, 1889. 



TWIG-GALLS OF THK ALEPPO PINE. 533 

Twig-galls of the Aleppo Pine.' 
The galls occurring on the twigs and branches of Pinu.'i 
halepc'iisis are even larger than those on the olive ; they are 
particularly common in the woods near Coaraze in the Maritime 
Alps. The galls contain masses of bacteria situated in canals 
and cavities in the parenchyma, and throughout the woody 
tissues inside the galls. Prillieux regards bacteria as the cause 
of the galls, and lie believes that they jjenetrate the healthy 
bark and form nests which kill the parenchyma. Experimental 
infection has, however, not yet been carried out. 

Canker of the Ash. 
Sorauer- regards the well-known ash-canker as the result 
of the action of bacteria, but Xoack thinks this improbable. 
■ Bacteria were found in the canker-spots only in summer, and 
might easily have got there accidentally after the formation of 
the galls. Galls of the ash caused by attacks of the in.sect 
Phi/tuptas may frequently contain bacteria. 

Canker of the Ivy, 
Lindau^ describes a cancerous formation on ivy-twigs, accom- 
panied by death of portions of the leaves. The diseased places 
contained slimy masses of bacteria, and the canker-spots, thou^'h 
at first isolated by formation of wound-cork, continued to extend 
till they reached the wood, which was ultimately killed. I'ure- 
culture and infection-experiments were not carried out, and the 
author himself was unable to determine whether the bacteria 
were primary agents in the canker-formation or only late arrivals. 

Lilac Disease. 

SfU'auer^ observed ma.sses of bacteria enclosi'd in cavities in 
young twigs of lilac which after becoming black-spotted had 
in many cases broken over. The attack and the i)arl taken in 
il by the bacteria were n<tt however investigated lurlher. 

' \'iiilleinin, " Sur iiiic tiiiiit.-m- ilii Tin ilAleii,"' Com/il. rnul., cvii., IHSS; 
I'rilliuiix (lor. cil.). 

-Suraucr, Atlu^ <L I'jldir.i iiLiiiiikln iltn ; N'oju-k, "l>fr Km-lu-iikifliM,'' Z'tl- 
Hihiij'l /. J'jhiini-iikraiikhtltm, iH'Xi, p. lO.S. 

'L'nuhw, /^lifirfiri/l /. I'jhtnztnkniidli, il> h, IS'.IJ, p. I. 

'S.,r,nii:r. Z-ilHi-hrijI /. /'jhiiiv iikimik/i- i/> n, IS'.M, p. Lsit, an.l |S!(J. p. :tU. 



534 THE PATH0C4EXIC BACTERIA. 

Bacterial Disease of the Mulberry.^ 

Cavities containing bacteria have been found in brown spots 
on diseased leaves and twigs of the mulberry. A form 
" Bacterium mori " was isolated and found to reproduce the 
disease when used to infect healthy leaves. I have myself 
observed, in the arboretum of the forest experimental station 
at Munich, most of the new twigs of an old mulberry tree 
beset with brown spots over the whole green tissue. The 
leaves on such twigs were not spotted, but died off prematurely. 
The spots indicated cavities filled with bacteria and a slimy 
substance. 

" Mai nero " of the Vine. 

This name is given to certain diseases of the vine, the cause 
of which has never been satisfactorily explained. Baccarini^' 
succeeded in obtaining all the symptoms of the disease after 
infecting healthy twigs by grafting on diseased pieces. Prillieux 
and Delacroix^ describe a similar disease prevalent in Tunis 
and throughout France, with the name " Aubernage." The 
wood when attacked exhibits black points which rapidly 
enlarge and coalesce, causing it to decay. All diseased elements 
were found to contain a brown gummy substance in which a 
form of Le2}tothrij-h?iQ.teYi\\\n swarmed. Inoculation of healthy 
vines produced the disease in the following year. 

Certain diseases of the grape have also been ascribed to 
bacterial action, and investigations are at present in progress. 

Sorghum Blight. 

A disease of species of Sorghum has been long known in 
America, especially on S. saccharatum, one of the sources of 
sugar. The symptoms are red or black spotting of the leaves 
and other parts of the plant. The disease may even be severe 
enough to cause death of the host-plants. Burrill in 1886 
found a bacterial form present in the spots, and named it 
Bacillus sorghi. Kellermann and Swingle^ obtained pure cultures, 

^ Boyer and Lauibcit, "Deux maladies du Alftrier," Compt. rend., cxvii., 1893. 

'^ Ma/pii/hia, vr. ; also Bullet, d. Soc. botai). Ital., 1894. 

•'"La gommose bacillaire d. Vigiies," Comptes rend., cxviii., 1894. 

* Report of hold III red department of Kansas State A(/rir. College, 1889. 



SORGHUM BLIGHT. 535 

and carried out successful experiments in infection of healthy 
Sorijliirin. 

Diseased fields should have the Sonjhuni stultble burnt out, 
and other crops cultivated on them for several years. 

Bacterial Disease of Maize. ^ 
From dark slimy spots on young maize-plants which had ilied 
from some unknown disease, liurrill isolated Burillus stcaUs. 
Pure cultures were obtained and minutely described, but no 
record is given of its use in infection-experiments. 

Red-coloration of Wheat. 
This is a phenomenon not uncommon on wheat-grain, where 
it may Ije epidemic. Prillieux- ascribes it to a Micrococcus 
which he found associated with it ; as, however, neither pure 
cultures were made nor any experiments in infection carried 
out, the cause of the disease is still doulilful. Examination of 
diseased grain showed that the starch-grains and even cell-walls 
had been dissolved. 

Mosaic Disease of Tobacco. 

This disease of ihi- tubaceu is well known in the Nether- 
lands. It makes its appearance as a mosaic-like pattern on 
tlie leaf, due to isolated spots becoming light-green, then dying. 
Mayer '^ ascribes the disease to the influence of bacteria, altiiough 
infection-experiments have hitherto failed : other observations 
on the disease do not conlirm this coutdusion. 

Potato-Rot.^ 

Kuhii described a dry-r<tt or tul)ei-rot of thr }>otalo which 
had been known since IS.'JO. The disea.se appears generally 
after harvest and lasts till spring. The tubers shrivel up and 
become very brittle. 

' liiiirill, A'jrir. Ex/ttr. Slation, C'liir. of Illinois, 1MS!>. 

• Aiiital's il. Mri. wit It,:, ScT. vi., 8, 187H, p. 248. 

■' " Ucber die Mosaik-kiiiiikheit dea TabakH," VtrsurhHulafiuu, WA. .'{'_', ISS(>. 

^ Kulin, /)if Kraid/ii it< II <l. K ii/tnr<j> inir/iMt-, iHfiS. 

Thu tfxtbooks of Kruiik ami Soriiuer. 

lifiiike anil Hi'itbolil, Dir Znxrlziiiiij il. Knrtofil i/nnh /'i/.-, IsTH. 

Kramer, < h^ilnri iri,. Innilnirlh. Cnitrti/Un/t, IMJII. 



536 THE PATHOGENIC BACTERIA. 

Another disease of potato-tubers quite distinct from the 
above is " wet-rot," which is widely distributed, and has been 
known since 1845. It appears on the field and shows itself 
by a putrefaction of the tubers. Kramer investigated tubers 
whose contents had liquefied inside the swollen skin. They 
contained unaltered starch-grains, remains of t