A text-book of plant diseases caused by cryptogamic parasites

M ASSEE

UN:

UNIVERSITY FARM

731

UNIVERSITY

A TEXT-BOOK OF PLANT DISEASES

A II rights reserved

A TEXT-BOOK OF

PLANT DISEASES

Caused by Cryptogamic Parasites

BY

GEORGE MASSE E

PRINCIPAL ASSISTANT (CRYPTOGAMS), ROYAL HERBARIUM, KEW

LONDON

DUCKWORTH and CO.

NEW YORK : THE MACMILLAN COMPANY
1907

First Edition, Jztly 1899.
Second Edition, April 1903.
Third Edition, 1907.

Edinburgh : T. and A. CONSTABLE, Printers to His Majesty

PREFACE

THE aim of this book is to enable those directly occupied
in the cultivation of plants, and with but a limited period
of time available for study, to determine the nature of
diseases caused by parasites of vegetable origin ; to apply
in the most approved manner those curative and preven-
tive methods which experience has shown to be most
successful in combating the particular form of disease
under consideration ; and finally, to include in the daily
routine of work precautionary measures which, without
being costly, frequently prevent a slight disease from
assuming the proportions of an epidemic.

Those desirous of obtaining fuller information respecting
the life-history of the parasites mentioned in this book,
also of others not included, can do so by consulting the
literature indicated under the different species. In con-
nection with this part of the subject, it may be well to
state definitely that success in the study of plant diseases,
or Vegetable Pathology, must necessarily be preceded by
a correct knowledge of the broad principles of the normal
mode of plant life, known as Vegetable Physiology ; and

a 2

185881

vi PLANT DISEASES

even apart from the subject of diseases, the cultivator
of plants possessed of such knowledge should succeed
better than another following blindly the ' rule-of-thumb '
method, if there is any truth in the saying that 'knowledge
is power.'

A certain amount of repetition will be observed ; this
is quite intentional. Not possessing the fascination of a
novel, it is not for a moment expected that the contents
of this book will be read from cover to cover even by
those most immediately concerned in its contents, but
rather that the particular disease respecting which infor-
mation is desired will be directly sought; hence under
each disease curative and preventive methods are fully
explained, in preference to referring to another disease
where the line of treatment is somewhat similar.

The numerous references to literature given indicate
my indebtedness to other workers in the domain of Plant
Pathology, to each of whom I offer my hearty thanks.

GEO. MASSEE.

PREFACE TO THE SECOND EDITION

NOTWITHSTANDING the short period of time that has
elapsed since the appearance of the first edition of this
little book, several very destructive diseases have either
appeared for the first time or have developed and extended
to an alarming extent during the interval. Chief amongst
such may be instanced the cucumber and melon leaf-
blotch, which has caused a loss of at least ^20,000
during the past two years to the growers of these plants
in the neighbourhood of London alone.

A word of justification is perhaps necessary in con-
nection with the often-repeated remark of gardeners to
the effect that giving the name or discovering the cause
of a disease is of no value unless accompanied by a
remedy for the same. Of course at first sight this infor-
mation appears to convey the same amount of satisfaction
as would the announcement by a fireman that your house
was on fire, but that he could not possibly extinguish the
flames. As a fact, however, the discovery of the cause
of a disease is of primary importance, as it is impossible
to formulate a cure for a disease the cause of which is
unknown.

GEO. MASSEE,

CONTENTS

INTRODUCTION

PAGE

Amount and kind of knowledge required by practical men —
Familiarity with names and habits of parasites — Pre-
ventive measures — Cures — Rule-of-thumb methods of
doubtful value, 1-3

FUNGI

Nature of fungi — Saprophytes — Parasites — Mode of growth
of fungi — Reproduction of fungi — How parasitic fungi
infect their victims — How the spores of fungi are dispersed
— Modes of dissemination of disease that can be prevented
— Danger connected with pruning — Selection of shade
trees, 4-28

LICHENES

Nature of lichens — Saprophytes or parasites? ... 29

ALGAE

Nature of Algae, ......... 29

MYXOGASTRES

Nature of Myxogastres or ' Slime fungi ' — Germination of

spores— Plasmodium stage, 29-30

CONTENTS ix

BACTERIA

PAGES

Nature of Bacteria — Groups of Bacteria — Nitrification induced

by Bacteria, . 30-3 1

FUNGICIDES

Nature of Fungicides — Solutions — Powders — Bordeaux
mixture — Ammoniacal solution of copper carbonate —
Potassium sulphide solution — Iron sulphide solution —
Permanganate of potash solution — Sulphur — Lime —
Resin wash — Jensen's hot-water treatment for wheat and
oat smut — Paraffin — Formalin — Lysol — Resin compound
— Fumigation with hydrocyanic acid gas — Sterilising soil
— Poisonous properties of fungicides, . . . . 31-47

ECONOMIC CONSIDERATIONS

Statistics relating to losses caused by grain rust in Prussia —
Loss through rust of wheat in Australia — Destruction of
vineyards in the United States caused by fungi, . . 47-51

SPRAYING

Various methods of spraying — Spraying apparatus, . . 51-53

FUNGOUS PARASITES

Descriptions, with preventive and curative methods, of the
various kinds of parasitic fungi attacking plants of
economic importance, ....... 53-334

MYXOGASTRES

Description of the diseases popularly known as ' Finger-and-

toe ' and Brunissure, . . . . . . . 334-338

XI 1

PLANT DISEASES

PAGE

PAGE

Phyllosticta prunicola

. 269

Rosellinia necatrix .

. 119

Phytophthora infestans .

• 63

Rosellinia radiciperda .

. 116

Phytophthora omnivora

. 67

Sclerotinia fuckeliana

• -149

Plasmodiophora brassicae

• 335

Sclerotinia sclerotiorum .

• 151

Plowrightia morbosa

• 137

Sclerotinia urnula .

• 154

Plasmopara viticola

• 9.71

Sphaerella fragrariae . -

. 108

Polyporus betulinus

. 190

Stereum frustulosum

- 173

Polyporus hispidus

192

Stereum hirsutum .

- 175

Polyporus sulphureus

• J95

Taphrina bullata .

. 90

Polystigma rubrum

• 135

Tilletia tritici .

. 219

Poria vaporaria

. 181

Uncinula spiralis .

- 93

Pseudopeziza trifolii

. 144

Urocystis colchici .

. 224

Puccinia asparagi .

. 240

Urocystis occulta .

. 222

Puccinia graminis .

12, 248

Uromyces betae

. 229

Puccinia pringsheimiana

• 243

Uromyces caryophyllinus

• 451

Puccinia pruni

. 251

Uromyces colchici .

. 227

Pythium de baryanum .

• 55

Ustilago avenae

. 211

Rhizopus necans .

• 58

Ustilago hordei

• 215

Rhytisma acerinum

• 143

Vermicularia circinans .

- 274

BLACK SCAB OF POTATOES

(Oedomyces leproides, Trabut.)

This must undoubtedly be considered as the most in-
jurious disease that has entered this country during recent
times, and unfortunately promises to prove more destructive
to the potato crop than even the renowned ' Potato disease,'
caused by Phytophthora infestans. The ravages of the
latter are to a very marked extent dependent on weather
conditions, and during a fine dry summer is but little in
evidence. Black scab, on the other hand, when once
introduced into the soil, is quite independent of weather,
and continues its ravages from year to year.

To add to the difficulty, no one has yet succeeded in
unravelling its life-history, or discovered in what way it
passes its time in the ground when free from a potato. It
is perfectly well known that when land once becomes in-
fested, Oedomyces retains its vitality for five years; in other
words, after a period of five years, potatoes planted in
infected land become badly diseased. It is a difficult,
in fact impossible matter to prevent soil infection, when
diseased tubers have once been planted, as in many in-
stances the crop of potatoes become so badly diseased that
many diseased tubers rot and completely decay in the soil
before the crop is lifted.

Beetroot, mangolds, and some other root crops can also
be attacked, but cereals, peas, and beans do not suffer.

The only effective treatment known is to apply gas-lime

xiii

xiv PLANT DISEASES

to infected land, and afterwards, for at least five years, sow
cereals or a crop not attacked, which means avoid growing
root crops.

The only safe method of dealing with diseased tubers is
burning.

The spread of disease by means of hybernating mycelium.

It has been proved in the case of potatoes attacked by
Phytophthora infestans, causing the well-known potato
disease, that the spawn or mycelium of the fungus enters
the young tubers, and when such tubers are used as 'sets,'
the mycelium passes from the tuber and grows up along
with the stems, enters the leaves, and if climatic conditions
are favourable, produces the disease on the leaves. The
mycelium also passes from the parent plant into the new
tubers, which in turn produce diseased plants. By this
method it follows that the offspring of a diseased tuber
is infected for all time. When the foliage of a potato
plant infected by the method explained above, produces
spores, such spores, dispersed by wind or animals, infest
other plants, and the disease is thus distributed. It is
owing to the production of spores on the foliage of potatoes
originally infected by mycelium spreading from the tuber,
that spraying is of some service. Spraying protects the
crop to the extent that it would suffer from the dispersion
of such spores, but it does not prevent the infection of the
new crop of potatoes from infection by the spawn travelling
from the stem of the plant into the new tubers. The fact
that a crop of potatoes remains apparently perfectly
healthy and free from disease, by no means proves that
there is no mycelium present in the tubers or foliage. It
has been definitely proved by experiments conducted at

BLACK SCAB OF POTATOES xv

Kew, that tubers known to contain mycelium produced an
apparently healthy crop, when grown in a comparatively
dry atmosphere, whereas portions of the same tubers, when
grown in a very damp, warm atmosphere, were quickly
destroyed by the disease.

It is highly probable that those sudden outbreaks of
potato disease, occurring simultaneously over a wide area,
and usually attributed to the rapid dispersion of spores,
are in reality due primarily to the presence of hybernating
mycelium in the parent tubers or * sets.' This mycelium
passed up the stem into the leaves, where it remained in
abeyance until its rapid development was favoured by a
succession of dull, damp, warm days. If such conditions
had not been forthcoming, the mycelium already present
in the leaves could not have developed into an epidemic.

Potato disease is now present in every part of the world
where the potato is cultivated, and we have no hesitation
in saying that the disease has been conveyed from one
place to another by means of hybernating mycelium in
the tubers, and not by means of spores. The disease
known as 'Potato leaf-curl,' caused by a fungus called
Macrosporium solani, is also conveyed from one generation
to another by means of hybernating mycelium in the
tubers.

When a potato tuber shows the livid, purplish blotches
so well known as indicative of potato disease, it would
probably not be used as a 'set' by any one. In many
instances, however, the tuber may contain mycelium with-
out showing any stains or discoloration either on the surface
or in the interior. The tubers containing mycelium of
'leaf-curl' never show any stains or discoloration, hence
its detection by the gardener is impossible.

xvi PLANT DISEASES

AMERICAN GOOSEBERRY MILDEW
(Sphaerotheca mors-uvae^ Schw.)

In the first edition of this book, this disease was briefly
alluded to, as proving injurious to European varieties of
gooseberries in the United States. In the second edition
its presence in Ireland was recorded, where it had proved
destructive in some districts, and appeared to be extend-
ing its area. We have now to record its occurrence in
England; it has also appeared in several European
countries. This disease is much more injurious than the
European gooseberry mildew, described at p. 95 of this
book, inasmuch as it attacks the fruit and renders it
useless, whereas the European mildew does not pass on
to the fruit. It first appears on the leaves and young
shoots as a white mildew, resembling in appearance the
hop mildew, to which it is allied. At a later stage the
fruit is attacked. The white mildew film gradually
becomes thicker in substance, and changes to a dingy
brown colour, and can be peeled off the fruit as a thin
felt-like layer. Numerous summer spores are produced
during the white stage; these are scattered by various
means and infect other bushes. At a later stage con-
siderable numbers of the winter form of fruit, under
the form of minute black points, are produced on
the matted, felt-like mycelium, These fruits remain in a
stationary condition during the winter, and start the infec-
tion the following spring. Experiments extending over
the last fifteen years have clearly proved that, by the usual
methods of spraying, this disease can be held in check.
Nevertheless, now that the disease has appeared in Eng-

AMERICAN GOOSEBERRY MILDEW xvii

land, growers of gooseberries have been much disturbed
by alarming statements that unless legislative measures
are at once instituted, gooseberry growing will within a
very short period of time be a thing of the past. How
legislation will in any way assist those who have the
mildew on their bushes at the present moment, is not
explained. One argument is that the mildew has been
introduced from the Continent. Poor Continent, how
conveniently situated to suggest such an idea ; how many
gooseberry bushes do you send us annually ? and why do
you allow the mildew to evade your laws specially for-
bidding its entry into your respective countries?

In reality there is not the slightest evidence that the
mildew was introduced into this country from the Con-
tinent, nor that it was introduced into Europe from the
United States. There are people in this country who state
that they have known the disease for the last thirty, or
even fifty, years without knowing what it was, from a
botanical point of view, and not being specially interested
in it, as it did no material injury. It is quite true these
people may be labouring under a mistake as to the identity
of the disease under consideration ; at the same time their
statements have not been proved to be wrong.

Undoubtedly the disease is a serious one, and not to
be ignored, and if allowed to run its course without any
attempt to check it. would prove, like finger-and-toe,
diphtheria, hop mildew, cholera, or plague, a serious
enemy.

Fortunately, however, remedies are to hand, which, if
applied with promptitude, will hold the disease in check ;
these are as follows : —

In this country the disease, as a rule, confines itself to

xviii PLANT DISEASES

the tips of the shoots, which for a distance of two or three
inches present a brown and shrivelled appearance; just
the appearance of tips that have been injured by. ' green
fly.' On examination of these shoots with a magnifying-
glass, the remains of the brownish matted mycelium of the
fungus can be seen, studded with a number of black
points, which are the winter form of fruit.

All such diseased tips should be removed during the
winter; the prunings, bearing the fungus, should be col-
lected and burned, and not dropped on the ground, accord-
ing to custom. During winter, before the buds begin to
swell, spray thoroughly with a solution of sulphate of
copper, one pound of sulphate dissolved in twenty-five
gallons of water to which a small quantity of soft soap is
added. Bordeaux mixture may be used instead of the
sulphate of copper solution. In the spring, just when the
leaf-buds are expanding, spray with a solution of potassium
sulphide (liver of sulphur) in water. In America it has
been found that half an ounce of potassium sulphide
dissolved in a gallon of water kills the mildew. If this
strength of solution, is found to scorch the foliage, more
water must be added ; in fact it would be advisible to try
first one ounce of the sulphide in three gallons of water.

A 'CLUSTER-CUP' DISEASE OF CONIFERS

(Calyptospora Goeppertiana, Tubeuf.)

' Cluster-cups ' is the popular name of one of the stages
in the life-cycle of many members of the group of fungi
known as rusts, of which rust of wheat is a well-known
example. All the rusts without exception grow on living

A 'CLUSTER-CUP' DISEASE OF CONIFERS xix

plants, and many are numbered amongst the most destruc-
tive of fungus parasites. ' Cluster-cups ' appear under the
form of clusters of minute white warts on living leaves.
These warts eventually burst open at the top and present
the appearance of minute cups with toothed edges curled
outwards, and are filled with bright orange powder which
in reality consists of myriads of spores. The spores from
' cluster-cups ' are scattered by wind and infect some other
kind of plant, and the resulting fungus presents a very
different appearance to the 'cluster-cup' form, although
in reality it is a portion included in the life-history of the
'cluster-cup.'

During recent years silver fir (Abies pectinatd) has
suffered from the attacks of Calyptospora. One stage of
the fungus grows on the Cowberry ( Vaccinum vitis-idaea\
causing the stems to become much thickened and spongy.
Such diseased stems are at first rosy-pink in colour,
gradually changing to deep brown. Diseased Cowberry
plants grow much taller than healthy plants, all the
branches are quite erect, and the leaves are much
dwarfed. If conifers happen to be growing in the neigh-
bourhood of diseased Cowberries, and spores from the
latter are carried on to the surface of young conifer leaves,
they become infected, and within three or four weeks after
infection two rows of cylindrical white cluster-cups appear
on the under surface of the conifer leaves. The spores
from the cluster-cups will infect Cowberry plants, but
will not directly infect other conifer leaves. On the other
hand, in the absence of conifers, the disease can continue
to reproduce itself on the Cowberry alone.

When conifers are attacked almost every leaf is infected.
Such leaves turn yellow and fall early. If this happens

xx PLANT DISEASES

two or three times to young nursery stock, the plants are
much retarded in development, or not unfrequently die
outright. Various other kinds of conifers, in addition to
the silver fir, are subject to this disease.

PREVENTIVE MEASURES. — It is important in selecting a
site for a nursery to ascertain that diseased Cowberries are
not present in the neighbourhood. Diseased plants are
readily recognised by the characters already given, more
especially by their erect habit and great height. If not
abundant, all such may be removed and burned.

PLANT DISEASES

INTRODUCTION

THE knowledge necessary to enable the horticulturalist,
farmer, or forester to utilise to the fullest extent the
discoveries of specialists relating to plant diseases, and
also to convey to others an intelligible account of the
particular form of disease respecting which information
is desired, may be arranged under three sections, as
follows : —

i. Familiarity with the general appearance and name
of the most frequent groups of parasites; their varied
modes of attack, and the special conditions favouring the
same ; also the relationship between the different forms
assumed by certain parasites during different periods of
their existence.

This last item of knowledge would, in one instance, have
saved from destruction a quantity of valuable young
standard pear-trees that were attacked by the pear leaf
cluster-cup fungus (Gymnosporangium sabinae). These trees
were cut down for the avowed purpose of preventing the
spread of the disease ; at the same time the solitary juniper
plant (Juniperus sabinae), the real cause of the mischief,
was, through lack of knowledge, allowed to stand.

n. PREVENTIVE MEASURES. — The old maxim, ' Preven-
tion is better than cure,' embodies the keynote to success

A

2 PLANT DISEASES

in combating, plant diseases ; in fact, if preventive measures
were intelligently, rigorously, and persistently carried out,
based on knowledge corroborated by repeated experiments,
it might safely be predicted that the frequent wholesale
destruction experienced at the present day would not be
repeated.

in. CURES. — Sometimes the attempt at effecting a cure
is a success ; frequently not. To the practical man, who
naturally hopes for a cure at every stage of a disease, the
result is generally disappointing. In the majority of
instances where an annual plant is attacked, cure is practi-
cally impossible, and in the case of perennials, the prospect
of a profitable crop for that year is slight. In such in-
stances, however, the disease can be arrested in its course,
arid a recurrence prevented.

Many people are apt to ridicule and throw discredit on
subjects with which they are not familiar, and possibly
some may consider that the items of knowledge indicated
above as being essential to a thorough grasp of the subject
can lead to no good. To those with the mind thus con-
stituted we fully agree that the attempt would result in no
good : ' A man convinced against his will, is of the same
opinion still.' On the other hand, the mind that can
grasp the fact that a certain amount of knowledge is
essential to the successful issue of any undertaking, will,
it is confidently hoped, not encounter any great difficulty
in acquiring a sound knowledge of the broad outlines of
the subject. The experience of many of the most success-
ful horticulturalists and others testifies that it well repays
the time devoted to the study.

The following remarks, written more than half a century
ago by the pioneer of Vegetable Pathology, so far as the

INTRODUCTION 3

subject of plant diseases is concerned, are unfortunately
to a great extent true at the present day : —

4 Every day's experience shows the wisdom of encouraging
amongst gardeners a higher order of education. It is not
enough for the present state of cultivation, or the require-
ments of intelligent masters, that they should be content
to follow in their predecessors' steps without attempting
anything beyond the usual routine, and taking advantage
of local circumstances either for the prevention of evil or
material improvements. Under a narrow system of educa-
tion and a low standard of qualifications, it may be well
to fall in with the common saw, " But he is a safe man and
will make no experiments," but a sound stock of principles
will at once dissuade from all unsafe experiments, and give
the power of meeting difficulties which to others would be
insurmountable' (Berkeley, Gard. Chron., Nov. 27, 1847).

The rule-of-thumb method of doing anything is pure
mimicry, that is, imitating more or less exactly, depending
on the amount of mimicry possessed by the operator, the
actions of some one else, without knowing or caring for
the reason why. Too much of this checks progress ; the
usual reply, that our forefathers succeeded without learning
all that is by some considered essential to success at the
present day, is not sound argument.

* Knowledge is power,' and the man who possesses the
greatest range of knowledge relating to his special subject
is the one most likely to succeed Hence it follows that
a knowledge of the broad principles regulating the mode
of life of those groups of parasites which prove so injurious
to cultivated plants should be clearly grasped; and as the
fungi are most numerous, they will be dealt with first.

4 PLANT DISEASES

FUNGI

A terse definition of the nature of a fungus is not
possible. Toadstool, mushroom, rust, mildew, and mould
are popular names for different groups of fungi, of which
we have above four thousand species in Britain alone,
whereas the Fungus-flora of the world includes above
fifty thousand species.

Accepting the fact that fungi are true plants, there is
one important feature in their life-history which must be
clearly understood, in order to realise why so many fungi
prey upon and kill plants belonging to other groups of
the Vegetable Kingdom. This feature relates to nutrition.
It is well known that flowering plants derive one portion
of their food from the soil, and another portion from the
air. These substances are inorganic, that is, they are not
the direct products of a living body, but under the
influence of the chlorophyll or green colouring matter
present in leaves these substances become converted into
plant food, an organic substance, the direct result of work
done by the living green leaves.

Now, fungi are entirely destitute of chlorophyll, hence
they cannot assimilate inorganic food, but require organic
food, and this they obtain by feeding on the bodies of
other plants. For this reason we always find fungi follow-
ing in the wake of flowering plants. Some few fungi
obtain their food from animal bodies, living or dead.
The different methods adopted for securing this organic
food enable us to divide the fungi into two groups.

i. Saprophytes. — Those fungi are termed saprophytes
that live on dead organic matter, as dead wood, heaps of
dead leaves, etc. ; and as such are not injurious to living

FUNGI 5

plants, they require no further notice in this work. The
great majority of gill-bearing fungi, or Agarics, belong to
this section.

ii. Parasites. — The enormous assemblage of fungi that
obtain their food directly from living plants, and con-
sequently act prejudicially to a certain extent on the
host, or plant on which they are parasitic, belong to the
present category. As too familiar examples may be
enumerated the various rusts, bunts, and smuts of cereals,
also the many mildews of living plants, along with numerous
other minute fungi which do not possess popular names,
and whose effects on their victims are usually attributed
to other than the true cause.

As a qualification of the above definitions, it must be
remembered that, under certain conditions, fungi which
usually live as saprophytes may become parasites, and
some such are to be numbered amongst the most destruc-
tive of fungi known. On the other hand, many dire
parasites can live as saprophytes during certain periods of
their existence.

MODE OF GROWTH OF FUNGI. — Gardeners and others are
often much disappointed, and their belief in the efficacy of
successfully combating plant diseases is lessened, when they
submit examples of plants which are stated to be showing
the first symptoms of disease, and receive in reply the
statement that it is too late to effect a cure, but that the
disease may, with the exercise of sufficient care and atten-
tion, be prevented from spreading. This unfortunate con-
dition of things is due to the fact that what the practical
man considers as the first stage of a disease, the pathologist
knows to be in many instances the last stage. This differ-
ence of opinion may be explained as follows : —

6 PLANT DISEASES

In preparing a mushroom-bed, it is well known that the
spawn or mycelium must grow and spread in the soil for
some time before it yields a crop of mushrooms. The
spawn or mycelium is the vegetative part of the fungus,
doing the same kind of work done by the root and leaves
of a flowering plant, that is, obtaining and assimilating
food. The part popularly called a mushroom does not
represent the entire fungus plant, but is in reality only
the fruit of the fungus or sporocarp, its use being to produce
spores, the equivalents of seeds ; and it appears above the
surface of the soil so that the ripe spores may be scattered
by wind and rain, the mycelium or vegetative portion of the
fungus remaining underground.

As a second example, take the black smut of oats. It is
well known that the only time this fungus can inoculate
and enter the tissues of the oat plant is just after the oat
seed has sprouted. At this period, if germinating smut
spores are present in the soil in which the young oat plant
is growing, their germ-tubes readily penetrate the delicate
tissues of the young oat, and once inside, the mycelium of
the fungus grows along with the oat plant until the latter is
nearly mature, when the fungus produces its powdery black
mass of spores in the fruit of the oat. To the popular mind
the appearance of the sooty mass of spores, being the first
outward and visible sign of the disease, is considered as
an early stage of its appearance, whereas the mycelium of
the fungus has been feeding on the substance of the oat
plant for months, in fact from the very earliest stage of
its existence.

As a rule the vegetative part of a fungus remains out of
sight, penetrating the tissues of the matrix, or substance on
which it is growing, the fruiting portion or sporocarp of the

FUNGI 7

fungus alone coming to the surface; and as the production
of fruit is the final act in the life of the fungus, it may
be accepted that the fungus has done its worst when it
produces fruit.

The above account shows that the argument frequently
brought forward, that as the fungus (sporocarp) has only
appeared on dying or dead parts, it cannot be the cause of
the disease, is not necessarily correct. On the other hand,
the presence of a fungus on a diseased portion does not
necessarily prove that the fungus was the cause of the dis-
ease. This has to be proved or refuted by proper methods.

An exception to this rule is met with in the group of fungi
represented by the hop mildew (Sphaerotheca castagnei^ Lev.),
where the mycelium or vegetative portion of the fungus
is quite superficial, forming white patches on the surfaces
of living leaves ; certain short branches of the mycelium,
called haustoria or suckers, pierce the epidermis of the leaf,
enter the cells, and absorb the food required by the fungus.
The mycelium consists of very slender, thin-walled tubes
called hyphae. In the fruit and certain other structures
these hyphae are densely interwoven, forming solid parts ;
and often the walls of the hyphae are thickened to such an
extent that a structure as hard as wood is produced.

REPRODUCTION OF FUNGI. — The majority of fungi are
short-lived, and the arrangements for reproduction, or the
continuation of the species, are usually provided for on a
very lavish scale. In this respect again, fungi differ very
materially from flowering plants. In the latter there is only
one form of fruit produced, the seeds of which reproduce
the species; whereas in the great majority of parasitic fungi
there are at least two distinct forms of fruit, and in many
kinds three or even four distinct and very different-looking

8 PLANT DISEASES

forms of fruit are produced throughout the season, each
performing a function not capable of being done by any
one of the other forms. These different kinds of fruit have
received special names, the value of which it is important
to clearly understand.

Taking as a first illustration the Vine Mildew (Plasmo-
para viticola, De Bary), we find that early in the summer
the leaves of diseased plants are more or less covered with
a delicate white mildew on the under surface, which is the
summer fruit, or conidial form of reproduction of the fungus
(Fig. i, i). This fruit originates from mycelium present in
the tissues of the leaf, the fruiting branches emerging
through the stomata or breathing pores of the leaf, for the
purpose of dispersing their conidia in the air. This mildew,
when examined under the microscope, is found to consist
of numerous much-branched hyphae, the tip of each branch
bearing two or three minute reproductive bodies or conidia
(Fig. i, 2). Without at present entering into details, these
conidia are capable of germination the moment they are
mature ; and being produced in immense numbers and in
rapid succession throughout the summer months, and being
readily dispersed by wind, rain, insects, etc., those that
happen to be deposited on the surface of a damp, healthy
vine leaf, germinate at once, enter the tissues of the leaf,
form a mycelium, and in a very short period of time produce
the white mould on the surface of the leaf, which in turn
becomes a centre of disease, producing conidia ready to be
scattered and further extend the mischief. This explains
the rapid extension of a disease which has once gained a
foothold among plants of the same kind that are grown in
considerable numbers, and in contact with each other, as in
vineyards and field crops generally.

Fig. i. — Vine Mildew (Plasmopara viticola).

io PLANT DISEASES

The function of the rapidly groivn, quickly germinating
conidia, produced throughout the summer season, while the
host-plant is in the full vigour of growth, is to enable the
fungus to extend its geographical area of distribution.

When the vine leaves begin to fade, the production of
summer fruit ceases ; and after the leaves have fallen, the
same mycelium, which during the summer has given origin
to conidia, now produces a second kind of reproductive
body called winter fruit, or technically oospores. These
bodies are also sometimes called resting-spores, from the
fact that, unlike conidia, they will not germinate the moment
they are mature, but only after a period of rest. Oospores
are spherical bodies of a dark brown colour, furnished with
a very thick, protective cell-wall, and are produced, often in
immense numbers, in the tissues of dead leaves (Fig. i, 5).
Although such diseased leaves often decay and disappear
during the winter or early spring, the oospores they con-
tained are not destroyed, but retain their vitality, lying on
the ground, and germinate about the month of May, pro-
ducing two or three germ-tubes much branched at the tip
and bearing conidia similar to the summer form of fruit
(Fig. i, 6). These conidia are dispersed by wind, and
those that happen to alight on the surface of a young, damp
vine leaf, germinate, enter the tissues of the leaf, form a
mycelium, which soon gives origin to the summer form
of fruit.

The function of oospores or the winter form of fruit is
that of continuing the species in time, or from one season
to another ; enabling it to tide over that period of the year
when its host-plant is also in a resting condition.

FUNGI n

The rust of wheat (Pucdnia graminis) has a more com-
plicated life-history, possessing four distinct structures
connected with reproduction, and, like many of its allies,
lives on different host-plants during different stages of its
development. Heteroedsm is the term used to denote
fungi that require to grow on two distinct hosts to com-
plete the full cycle of their development.

The spring condition of wheat rust, called the Aecidium
or ' cluster cup ' stage, occurs on the leaves, young shoots,
sometimes also on the flowers and young fruit, of the bar-
berry (Berberis vulgaris\ under the form of clusters of
minute cup-shaped structures with white, fringed margins,
and filled with golden-yellow spores (Fig. 2, 8 and 10).

Other bodies, considered to be in some way connected
with reproduction, known as Spermogonia^ are produced by
the fungus on barberry leaves, accompanying the aecidium
condition, but nothing definite is known respecting them.

The mature aecidium spores are scattered by wind, and
those that happen to alight on the leaves of wheat or
various other grasses, germinate if the surface is damp ;
the germ-tube enters the tissues, where it forms a mycelium,
and in a very short time produces dense groups of rust-
coloured uredospores, which burst through the tissues of
the leaf, forming the rust-coloured streaks on its surface,
known as wheat-rust (Fig. 2, i and 2). Uredo or summer-
spores are produced in immense numbers throughout the
summer months, thus securing the spread of the disease.

During the autumn teleutospores or winter-spores are
produced by the mycelium that gave origin to uredospores
earlier in the season. The streaks formed on the leaves
by the teleutospores are much darker in colour than those
produced by the uredospores (Fig. 2, 5). The teleuto-

I! Y F;

Fig. 2. — Rust of Wheat (Puccinia graminis}.

FUNGI 13

spores remain firmly attached to the leaves, and may
often be found in a living condition on rotten straw in
a manure-heap.

During the spring following their production, the
teleutospores germinate, giving origin to a few very minute
reproductive bodies called secondary-spores (Fig. 2, 7),
which are dispersed by wind. Such of these as alight on
barberry leaves give origin in turn to the aecidium or
cluster-cup stage of the fungus.

The above account briefly describes the complete life-
cycle of wheat rust ; but it is important to remember that
the continuance of the species does not require that it
should be repeated every season. The uredo or summer-
spore condition alone is sufficient to perpetuate the disease
from year to year, growing during the winter on the leaves
of wild grasses in sheltered situations, as hedge-banks, etc.,
and passing from thence to young wheat.

In addition to the above, and other modes of repro-
duction by means of various kinds of conidia or spores,
fungi are also reproduced by the mycelium or vegetative
portion of the fungus, which under certain conditions
becomes highly specialised for this purpose. The most
usual form of vegetative reproduction consists of densely
compacted masses of hyphae called Sclcrotia. These
sclerotia are globose or irregularly shaped masses, varying
in size from that of a pin's-head to a cricket-ball, depending
on the fungus to which they belong. The outside is
generally blackish, the inside white. These bodies are
formed, often in large numbers, in the substance of the
plant on which the fungus is growing. When the host-
plant decays, the sclerotia remain in the soil in an
unchanged condition until the following season, when

14 PLANT DISEASES

they produce some form of reproductive body which
inoculates the young host-plant. In many instances
sclerotia are formed in living parts of the host, especially
in bulbs, where they remain latent until the bulb pro-
duces a new growth, which is infected in due course.

From the above account it will be seen that sclerotia
perform the same function as winter-spores, remaining
passive during the resting condition of the host, and pro-
ducing fruit when the latter commences a new growth.

How PARASITIC FUNGI INFECT THEIR VICTIMS. — The
conidia or spores of numerous parasitic fungi, carried by
wind, rain, or other agents, are deposited on the leaves,
fruit, or other parts of the host-plant, germinate at once,
and enter the tissues. This may be considered as the most
direct and general method of infection.

Armillaria mellea, an exceedingly common gill-bearing
fungus, or ' toadstool,' very destructive to forest and
orchard trees, illustrates a second mode of attack.

The fungus often lives as a saprophyte, growing in
dense clusters on decaying stumps, etc. Its mycelium
forms thin, cordlike strands which radiate in all directions
in the soil ; and if one of these strands of mycelium comes
in contact with the living rootlets of a tree, its tissues are
attacked, the mycelium of the fungus enters the rootlet,
adopts a parasitic mode of life, spreading further and
further into the tissues, until finally the whole root-system
of the living tree is enveloped in a white, felty mycelium,
which gradually extends up the trunk, ending in the death
of the tree.

In the meantime, numerous strands of mycelium origin-
ating from the diseased tree are traversing the soil in
every direction in search of other victims, and by this

FUNGI 15

means neighbouring trees may eventually be destroyed
by the mycelium spreading originally from a single centre
of infection.

A third mode of attack is practised by certain fungi
known as wound-parasites; that is, fungi whose spores
are not capable of directly penetrating living tissues, but
at first require to live as saprophytes, changing gradually
to a parasitic mode of life. This is effected by the spores
of such fungi germinating on a wounded surface, as a
broken branch, pruned branches, the cut surface of which
has not been properly protected, bruises caused by hail-
stones, the nibbling of rabbits, mice, etc. The mycelium
first produced lives in the decaying tissues of the wound,
and gradually attacks the adjoining living tissue.

Forest and fruit trees are more especially attacked by
wound-parasites belonging to the genera Polyporus and
allied forms. As a rule, the heart-wood is first attacked,
the mycelium gradually extending to the circumference,
until finally the trunk becomes quite hollow, owing to the
wood being reduced to powder by the corroding action of
the mycelium of the parasite.

Hollow trunks are generally due in the first instance to
the attacks of parasitic fungi, and are not, as popularly
supposed, the result of old age and what is termed natural
decay.

How THE SPORES OF FUNGI ARE DISPERSED. — Mention
has already been made of the dispersal of spores by wind,
which must be considered as the most general agent for
enabling spores to reach a position suited to their require-
ments ; at the same time, experiments indicate that spores
are not transported over those immense distances that was
at one time considered probable. The influence of wind

16 PLANT DISEASES

in disseminating spores is most apparent where numerous
plants of the same kind grow in close proximity, as in the
case of a field of corn, when a gentle breeze is sufficient to
bring diseased and healthy plants in contact ; and if the
leaves are damp with dew or rain, such conditions are
highly favourable to a rapid extension of disease.

Heavy rain washes spores to the ground, where they
germinate and perish in the absence of the proper host;
whereas a slight shower or gentle drizzle favours the spread
of a disease, by washing spores from one part of a plant to
another or on to adjoining plants.

Insects, birds, snails, and slugs are known to be un-
conscious agents in the dispersion of spores, whereas
dogs, hares, rabbits, etc., running through a field of corn,
potatoes, or turnips, act after the fashion of wind, by
bringing into contact adjoining plants.

Spores or fragments of mycelium capable of growing
are too frequently transported from infected to healthy
localities by human agency. As illustrations may be
mentioned the spores of the ' finger-and-toe ' disease of
cabbages and turnips, which are readily transported in soil
adhering to cart-wheels, tools, shoes, etc. Spores are also
readily transported by clothing ; a gardener moving about
among a number of closely packed chrysanthemums can
hardly fail to brush off some of the powdery uredospores
of the chrysanthemum rust, if such is present, and will
as certainly have the spores brushed off his clothing by
other plants.

Parasitic fungi attacking plants grown under glass are to
a great extent deprived of those means of spore dissemina-
tion so efficient to fungi growing in the open air. This loss
is, however, perhaps more than compensated for by those

FUNGI 17

modes due to human agency already mentioned ; and
perhaps the most efficient method of all is that effected
by syringing. By this means spores are dispersed over
every part of a house, some of which, in the ordinary
course of things, will fall upon damp leaves. Syringing is
simply tempting Providence in those instances where the
house contains plants of one kind only, and where the
presence of a disease is known, or even suspected.

It has been suggested, in the case of the chrysanthemum
rust epidemic, that in one instance the disease was in-
troduced owing to syringing the plants with rain water,
supposed to contain the spores of the fungus that had
been carried from the roof into the cistern.

I am quite conscious of the fact that the practical man
will retort, Gardeners must move about among plants, and
spraying is a necessity. This may be considered good
argument ; nevertheless, it is well to be in possession of
all known facts bearing on the movements of the enemy,
as such knowledge must precede any attempt to apply a
cure.

So far as danger from the use of water is concerned, this
can be obviated by adding a wineglassful of paraffin to
three gallons of water. This proportion is sufficient to
destroy germinating spores, and will not injure, but in
reality benefit, the plants in other ways.

MODES OF DISSEMINATION OF DISEASE THAT CAN BE
PREVENTED. — Dr. Erwin F. Smith, an American vegetable
pathologist, said, in a lecture on plant diseases, 'Competi-
tion is not likely to decrease, nor are prices likely to
advance very much, and the profits must come from
avoiding losses.' Hence the following suggestions : —

Probably the commonest source of plant infection arises
B

i8 PLANT DISEASES

through carelessness in not promptly destroying by burning
diseased plants, fruits, bulbs, etc., which in most instances
can be readily done without much expense or loss of time.
For instance, it is not unusual to see quantities of diseased
leaves and fruit on the ground in orchards. If such are
allowed to remain, the fungi present continue to produce
spores, or winter-spores or sclerotia are formed; and al-
though the leaves and fruit ultimately decay and disappear,
the spores and sclerotia do not perish, but remain on the
ground until the following spring, when they give origin to
spores that are conveyed to the young leaves, and the
disease appears once more. Of course, the cultivator of
plants cannot directly prevent the diffusion of spores by
wind or other agents ; but what he can do — and what it
pays to do — is, by systematic cleanliness and promptitude,
to prevent, to a very great extent, the formation of spores
on the plants over which he exercises control.

Burn all diseased plants, fruit, and bulbs, and do not
throw them on the manure-heap, which means securing a
recurrence of the disease.

It has been already explained that the majority of
parasitic fungi possess more than one form of fruit ; and
furthermore, the summer form of fruit is the one that pro-
duces a quickly spreading disease or epidemic, usually
appearing in late spring or early summer, and con-
tinuing to extend its ravages throughout the season, unless
checked.

When a disease appears, remove the diseased plants, and
spray the remainder at intervals with solution of potassium

FUNGI 19

sulphide if growing indoors, or with dilute Bordeaux mixture
if outdoor shrubs or trees.

Numerous diseased portions of plants find their way to
the manure-heap, either directly — which is a serious mistake
to commit at any time or under any circumstances — or
indirectly, after being used for fodder, as rusted straw of
cereals, chaff, also roots, tubers, etc. In a sweating, moist
manure-heap, the numerous spores and sclerotia present in
such diseased plants find a congenial home, multiplying
rapidly under various spore-forms as saprophytes ; and if
the manure is used while fresh or green, a disease will in
all probability follow, if the plants manured happen to be
of the kind the fungus-spores can attack. 'Smut' of cereals,
drooping disease of paeonies, and many other diseases, have
been proved to have been introduced with manure.

The practice of burying primings, as followed in some
tea plantations, should be discontinued. Such should be
burned. The small amount of advantage gained in the
way of manure is not a sufficient justification, as against
the possible, or probable, danger of further spreading a
disease by following this practice.

Do not throw diseased plants on to the manure-heap, nor
into piggeries, etc. Fresh or green manure should not be used
for land intended for cereals. Only old and thoroughly rotten
manure should be placed on the ground over the roots of rose
trees, young orchard or forest trees, or over perennials that
die down in the autumn.

The destructive sugar-cane disease (Trichosphaera sac-
chart) was disseminated wholesale by the thoughtless

20 PLANT DISEASES

practice of using diseased canes for purposes of propaga-
tion. Bulbs or tubers infested with sclerotia naturally
produce diseased plants ; it is for this special object that
the sclerotia are present. Cuttings from diseased plants
are prone to perpetuate the disease, even if the particular
cutting used appeared to be free from the disease. To
understand this statement, it must be remembered that
when the mycelium of a parasitic fungus has entered the
tissues of a host, it usually spreads far beyond those points
where it announces itself by killing portions of the host,
and producing its fruit on the surface of such dead or
dying parts. Furthermore, mycelium possesses the power
of remaining latent for a long period of time, and of assum-
ing an active condition when favourable circumstances
present themselves.

Finally, the seed of diseased plants often produces
diseased seedlings, as in the ' sleepy disease ' of tomatoes.
An instance of this kind came under my observation : a
fine hollyhock growing in my garden was severely attacked
by the hollyhock rust (Pucdnia malvacearum\ the calyx
and even the carpels being studded with the small brown,
wartlike pustules of teleutospores. The seed of this
diseased plant was sown in due course, and, in a large
percentage of the seedlings, the characteristic fruit of the
fungus appeared on the cotyledons.

Cuttings from diseased plants should not be used for
propagation. Bulbs or tubers produced by diseased plants
perpetuate the disease, and do so with certainty if sclerotia
are present. Seed produced by diseased parents should not
be sown. Seedsmen should be required to give a guarantee
that seed offered for sale was obtained from healthy plants.

FUNGI 21

Certain especially destructive forms of fungi are capable
of living and extending in a vegetative manner in the soil,
and are consequently combated with great difficulty. Such
fungi are unfortunately equally capable of becoming true
parasites when the mycelium comes in contact with the
roots of living plants, and possess the further distinctly
objectionable peculiarity, from the human standpoint, of
not being so fastidious in their choice of a host as is
customary with fungi, but attack, almost indiscriminately,
every plant that comes in their way. Among such may
be enumerated white root-rot (Dematophora necatrix\
New Zealand root-rot (Rosellima radiciperda), tree root-
rot (Armillaria mellea), conifer root-rot (Femes annosus),
and various others.

Where rotting of the roots of trees is caused by fungi that
extend their range by means of mycelium spreading in the
soil, it is advisable, as suggested by Hartig, to isolate such
diseased trees by a narrow trench about eight inches deep,
making the trench sufficiently distant from the trunk so as to
be outside the spread of the roots. Throw the soil removed
inside the trench.

Many parasitic fungi can only live on one particular
host-plant, and the majority are confined in their ravages
to closely related plants, or at most to plants belonging
to the same Order. Hence a disease spreads quickly when
numerous plants of the same kind grow in close proximity,
whereas when the vegetation is of a mixed character, those
plants not susceptible of the disease intercept numerous
spores, and thus to a great extent protect the susceptible
plants.

22 PLANT DISEASES

It is an indisputable fact that the presence of numerous
plants of the same kind, and of the same age, massed
together, not to say crowded, favours the spread of a given
disease ; in fact, all epidemics on a large scale naturally
require such conditions, as the potato disease {Phytophthora
infestans\ rust of wheat (Pucdnia grafftinis), vine mildew
(Plasmopara viticola), larch canker (Dasyscypha calycind),
and others.

It is fully realised that in many instances myriads of
plants of the same kind, and of the same age, must exist,
as in the case of cereals, and in fact practically all field
crops ; nevertheless it is well that the disadvantage of this
method should be known, even if it cannot at present
be obviated.

On the other hand, is it absolutely necessary, or even
advisable, to crowd a house with tomatoes alone, or with
chrysanthemums, or to plant pure forests or plantations?
Experience proves that such a proceeding is not con-
ducive to the well-being of plants so treated, and it rests
with the practical man to avoid the danger as far as
possible.

Avoid massing together plants of the same kind whenever
circumstances permit.

Mention has already been made of the group of fungi
called wound-parasites on account of their gaining admis-
sion to living tissues through some wound or broken
surface. Many such wounds are beyond the control of
human agency, either to avert or to protect from serving
as a starting-point for the attacks of fungi. Among these
are wounds caused by hailstones, cracks and wrenches

FUNGI 23

produced by the weight of snow lying on branches,
frost, punctures made by insects, animals, etc. On the
other hand, many wounds are well under control; broken
branches should be removed, the ' snag ' sawn off, and
the wounded surface protected. In pruning, every wound
should at once be protected by a coat of tar ; and just
now, when it is the rage to prune almost every kind of
tree, however beautiful and flowing its natural contour,
into a conical monstrosity resembling in outline those
wonderful toy trees made in Germany, the wounds made
are so many, that if not promptly protected, attack from
some fungous foe is practically certain. The danger
may not be evident at once, perhaps not for several
years, but the following quotation on pruning young trees,
from Schlich's Manual of Forestry ', may be accepted as
authoritative : —

'As a general rule, plants should not be pruned unless
it is absolutely necessary. Every cut produces a wound,
exposing the plant to disease, which may ultimately render
it unfit for the purpose for which it has been grown.
Recent researches have shown that the unhealthy con-
dition of timber trees may be due to spores of fungi
entering the tissues through wounds received at a very
early age.'

Wounds in ade by pruning should be immediately protected
by a coat of tar or some other substance capable of preventing
the germination of spores on the cut surface.

Most people have observed that even in the worst cases
of a disease, certain plants remain unscathed, and in certain
instances it has been proved that the descendants of these
plants also possess — we had almost written inherited — this

Fig- 3-— Section of the stem of a young apple-tree,
showing the effect of pruning and not protecting the
cut surface. The shaded portion is diseased, and the
tree died from the effect some years after the fungus
first attacked it.

U N I V E R S i i

o>

JALIFOH;

FUNGI 25

immunity. It is also an established fact that in many
instances certain forms or varieties of a cultivated plant are
much more resistant to disease than others. This idea
has been clearly established by Dr. Cobb in connection
with wheat and its fungous enemy (Puccinia gramim's).
Unfortunately, it has also been demonstrated that varieties
that have been proved to be comparatively immune in one
particular district are equally or even especially susceptible
to the disease when removed to another locality ; or forms
that have behaved in an encouraging manner for a certain
period of time have afterwards lost this power. Never-
theless, it is encouraging to know that in particular districts
certain varieties are more disease-proof than others, and in
all probability further investigation of this phase of the
subject will result in the development of disease-resisting
varieties. This peculiarity turns on some, probably slight,*
modifications, morphological or physiological. But it is
always well to remember that however much the host-plant
may succeed, aided or unaided, in guarding itself against
its foe, fungi, on the other hand, have proved themselves
equally capable of adaptation to existing circumstances.

Evidence forthcoming supports the idea that, by careful and
continued selection, disease-proof varieties of plants may be
produced and perpetuated.

Care should be taken to prevent the spread of disease
directly by human agency. This too frequently occurs,
especially in the case of those fungi whose mycelium spreads
in the soil ; also resting-spores and sclerotia. These are
carried from place to place by the soil adhering to shoes, tools,
cart-wheels, etc. Summer-spores are also diffused by adhering
to clothing.

26 PLANT DISEASES

In many instances where the soil has become infested
with resting-spores or sclerotia, it is very unwise to continue
growing the same kind of crop, and under the circumstances
rotation of crops ; selecting those that the fungus present in
the soil does not attack is undoubtedly the best thing to
do under the circumstances. Deep ploughing is some-
times resorted to for the purpose of burying the spores or
sclerotia, but for other reasons this cannot always be done.
Where rotation of crops cannot be followed out, very
frequently what is termed a trap-crop is found to be useful
in clearing the soil of disease germs.

As an illustration of this method, we may take the
case of the disease known as ' finger-and-toe ' of cabbages,
turnips, radishes, and other cruciferous plants. The
myxogaster causing ' finger-and-toe ' is essentially an under-
ground organism, living on organic matter in the soil,
or as a parasite in the roots of plants. It has been
proved that in the case of badly infected soil, if a crop of
any quick-growing cruciferous plant is grown early in the
season, the plants become diseased. After the trap-crop has
thus caught up the disease, it should be removed at once,
and immediately afterwards the same ground may be
planted with cabbages or turnips, which will remain free
from the disease. This. method would undoubtedly prove
of great service in many forms of disease, where the inocu-
lating bodies are present in the soil. The points to re-
member are : the trap-crop should consist of some plant
readily susceptible to the disease it is intended to catch,
and that after becoming diseased, it should be removed
before spores or sclerotia are produced.

Rotation of crops and the employment of trap-crops are to

FUNGI 27

be recommended for the purpose of checking disease, especially
in those instances where the inoculating bodies are present in
t}ie form of testing-spores or sclerotia in the soil.

Shade trees are commonly employed in tropical countries
for the purpose of affording shelter to plants under cultiva-
tion, especially in the case of tea, coffee, and cacao.

This is a subject worthy of much more attention than
it appears to have received up to the present, although
Dr. Watt has some remarks to the point in connection
with tea culture in India.

There is grave danger of introducing or perpetuating
disease unless great care is exercised in the selection of
shade trees.

As previously stated, parasitic fungi as a rule confine
their attacks to closely allied plants, or at most to plants
belonging to the same Order. For this reason it would not
be advisable to utilise as shade trees such as are closely
allied to the plants under cultivation.

Another point of importance is to ascertain whether
fungus parasites likely to attack cultivated plants are
present on wild plants in the jungle or forest.

Hemileia canthii. Berk, and Broome, infests Plectronia
campanulata, Bedd. (= Canthium campanulatum, Thwaites),
a wild plant common to Ceylon and India, and the parasite
on the leaves of this plant is so close to the Hemileia vasta-
trix, Berk., the coffee leaf disease, that it is doubtful
whether the two parasites are not identical, the minute
differences observable being due to difference of host.
Again, Hemileia woodii, Kalchbr. and Cooke, appears to be
not uncommon on two small trees allied to the coffee
plant, Vangueria tn/austa, Bruch, and Vangueria latifolia.

28 PLANT DISEASES

The former occurs in tropical and South Africa, the latter
in Natal. The same parasite also occurs on leaves of an
unknown plant from Natal. This parasite again is so close
to that of the coffee leaf disease, that it is almost certain,
opportunity afforded, the parasite would pass from one to
the other. To start a coffee plantation in the neighbour-
hood of the Vangueria would in all probability mean
disaster. Allied plants usually require the same food con-
stituents, whereas plants belonging to different Orders in
many instances do not rob each other of the same kind of
food derived from the soil, but actually mutually benefit
each other. The value of rotation of crops turns mainly
on this feature in plant life. It has been known for
centuries that the fertility of the soil could be increased
by the growth of leguminous plants, and Dr. Watt — Pests
and Blights of the Tea Plant, p. 169 — has shown that
leguminous trees, as Acacia dealbata, Dalbergia assamica,
Albizzia stipulata (sau tree), and others belonging to the
same family, proved highly beneficial to the tea plant by
enriching the soil, in addition to serving the function of a
shade tree.

Finally, success in eradicating plant diseases depends
almost entirely on universal co-operation. It is compara-
tively waste time and money attempting to hold a particular
disease in check, especially in those instances where spores
are carried by wind, if your neighbour, whose plants are
suffering from the same disease, does not exercise ordinary
precautions.

LICHENES 29

LICHENES

The immense number of plants belonging to this family
differ from fungi in possessing chlorophyll, and conse-
quently can assimilate inorganic matter. A lichen in
reality consists of a body formed of two distinct elements,
a fungus and an alga, the two living together and mutually
assisting each other in the procuration and assimilation of
food, a condition known as mutualism ; differing widely
from those cases where a parasitic fungus lives on another
plant, in which case the parasite has all the advantage,
and the host, or plant preyed upon, all the disadvantage.

Lichens often form leafy expansions covering the trunks
of trees, and such are not parasites, although their presence
does not benefit the tree, especially when young. On the
other hand, many lichens vegetate in the living bark or on
coriaceous evergreen leaves, especially in the tropics, and
may fairly be considered as parasites.

ALGAE

Seaweeds are the best-known representatives of this
family, although numerous representatives live in fresh-
water streams, ditches, and ponds. All the members
possess chlorophyll ; nevertheless, some of the simplest
forms are parasitic on higher plants, while others live in
a condition of mutualism.

MYXOGASTKES

The Myxogastres or ' Slime-fungi ' were at one time
considered as belonging to the fungi, but are now separated
on account of important structural differences, and by some
are considered as belonging to the animal rather than
the vegetable kingdom.

30 PLANT DISEASES

The spores on germination give origin to amoeboid
bodies capable of exercising a sluggish movement. These
bodies coalesce in quantities to form a naked mass of
protoplasm, also capable of movement, called a plasmodium.
This represents the vegetative stage. No mycelium is
developed during any period. The plasmodium eventually
becomes stationary, and resolves itself into a mass of
minute spores.

Several organisms considered to belong to this group are
suspected as being parasitic on plants, the best known and
most destructive being the one causing 'fmger-and-toe'
disease in cabbages, turnips, etc. (Plasmodiophora brassicae),

BACTEEIA

These infinitesimally minute organisms, popularly termed
'germs' or 'microbes,' are better known as the cause of
numerous animal diseases; in fact, it is only in comparatively
recent times that bacteria have been connected with plant
pathology. At the present day numerous plant diseases
are attributed to bacteria, some truly, others doubtfully so.

Bacteria are distinguished according to their shape : —

(1) Cocci are spherical, either solitary or united in groups.

(2) Bacilli are straight rods.

(3) Spirilla are spirally curved rods.

Numerous forms of bacteria possess the power of
voluntary movement, due to the presence of minute cilia
or flagella.

Multiplication takes place in two distinct ways: (i) by
fission — hence the name Schizomycetes sometimes given to
the group. When an individual has attained the normal
size it divides into two portions, each of which continues to
grow until the normal size is reached, when the process is

BACTERIA 31

repeated. (2) By spores, which are termed endogenous,
when formed within the cell ; arthrogenous, when portions
separate from the cell and gradually develop into distinct
individuals.

The changes effected by bacteria on the substance on
which they are living are very varied, and included under
the term metabolism. Bright colours are often produced \.
odours agreeable or otherwise are also common ; some
again induce phosphorescence. Putrefaction and fermen-
tation also result.

Certain species possess the property of forming nitrates
by the conversion of ammonia into nitric acid, saltpetre —
potassium nitrate — being one of the ultimate products.

A most important feature to remember, from the stand-
point of the cultivator of the soil, is the fact that what has
been termed ' nitrification ' of the soil, or the fixation of
nitrogen in a form that can be readily assimilated by
plants, to whose existence it is indispensable, is effected
by bacteria present in the soil ; hence it is important, in
attempting to destroy fungous germs present in the soil,
not to make use of substances also capable of destroying
the indispensable bacteria present.

FUNGICIDES

The various preparations applied to plants for the pre-
vention of diseases caused by parasitic fungi are called
fungicides.

A fungicide to be of value should possess the following
points : (i) Destroy the parasite without injuring the host.
(2) Be easy to prepare and to apply. (3) Cost moderate
or even cheap.

32 PLANT DISEASES

From amongst the numerous solutions and powders that
have been experimented with, the following have proved
most effective : —

SOLUTIONS

(1) Bordeaux mixture.

(2) Ammoniacal solution of copper carbonate.

(3) Solution of potassium sulphide (liver of sulphur).

(4) Solution of iron sulphate.

(5) Solution of potassium permanganate ( = Condy's fluid).

(6) Paraffin. Formalin. Lysol.

POWDERS

(1) Sulphur.

(2) Quicklime.

BORDEAUX MIXTURE. — This substance is universally
admitted to be the most effective fungicide known. Its
various advantages are indicated as follows by Professor
B. T. Galloway of the United States Department of Agri-
culture: (i) Its thorough effectiveness as a fungicide;
(2) its cheapness ; (3) its safety from a hygienic standpoint ;
(4) its harmlessness to the sprayed plant ; and (5) its
beneficial effects on plants other than those resulting from
the mere protection against the attacks of parasites.

The same high authority gives the following improved
method of preparing Bordeaux mixture : —

'All things considered, it is believed that the best
results will be obtained from the use of what is known as
the 5o-gallon formula of this preparation. This contains :

Water .... 50 gallons.
Copper sulphate . . 6 pounds.
Unslacked lime . . 4 pounds.

FUNGICIDES 33

'In a barrel or other suitable vessel place 25 gallons of
water. Weigh out 6 pounds of copper sulphate, then tie
the same in a piece of coarse gunny sack, and suspend it
just beneath the surface of the water. By tying the bag to
a stick laid across the top of the barrel, no further attention
will be required. In another vessel slack 4 pounds of
lime, using care in order to obtain a smooth paste, free
from grit and small lumps. To accomplish this, it is best
to place the lime in an ordinary water-pail and add only a
small quantity of water at first, say a quart, or a quart and a
half. When the lime begins to crack and crumble, and the
water to disappear, add another quart or more, exercising
care that the lime at no time gets too dry. Towards the
last, considerable water will be required, but if added care-
fully and slowly, a perfectly smooth paste will be obtained,
provided, of course, the lime is of good quality. When the
lime is slacked, add sufficient water to the paste to bring
the whole up to 25 gallons. When the copper sulphate is
entirely dissolved and the lime is cool, pour the lime milk
and copper sulphate solution slowly together into a barrel
holding 50 gallons. The milk of lime should be thoroughly
stirred before pouring. The method described ensures
good mixing, but to complete this work, the barrel of liquid
should receive a final stirring, for at least three minutes,
with a broad wooden paddle.

' It is now necessary to determine whether the mixture
is perfect — that is, if it will be safe to apply it to tender
foliage. To accomplish this, two simple tests may be used.
First insert the blade of a penknife in the mixture, allowing
it to remain for at least one minute. If metallic copper
forms on the blade, or, in other words, if the polished
surface of the steel assumes the colour of copperplate, the

C

34 PLANT DISEASES

mixture is unsafe, and more lime must be added. If, on
the other hand, the blade of the knife remains unchanged,
it is safe to conclude that the mixture is as perfect as it can
be made. As an additional test, however, some of the
mixture may be poured into an old plate or saucer, and
while held between the eyes and the light, the breath should
be gently blown upon the liquid for at least half a minute.
If the mixture is properly made, a thin pellicle, looking
like oil on water, will begin to form on the surface of the
liquid. If no pellicle forms, more lime should be added.'

It is very important to remember that air-slacked lime
should never be used in the preparation of Bordeaux
mixture, since its use results in injury to the foliage.

The adhesive property of Bordeaux mixture is much
increased by adding soft soap in quantity equal to that of
the copper sulphate. This is especially necessary when
spraying smooth or waxy leaves, the soap increasing the
tendency of the liquid to spread instead of forming into
large drops, which roll off the surface of the leaf.

Since the discovery of Bordeaux mixture by Millardet in
1885, the general tendency has been to reduce its strength ;
and even prepared in the proportions given above, it some-
times slightly scorches tender, young foliage. Hence it is
advisable to dilute the mixture for spring spraying, using
the full strength when the leaves are full grown, and again
reducing the strength when spraying young fruit. Apples,
pears, and cherries may be sprayed until half grown, when
the operation should cease, otherwise the ripe fruit is liable
to be spotted.

With the dilute mixture found to be efficient, the sprayed
foliage does not present the appearance of having been
whitewashed to the same extent as when a denser mixture

FUNGICIDES 35

was used. Nevertheless, the effect produced is perhaps
sufficient to forbid its use in private or public parks or
gardens, or conservatories. On the other hand, to the
horticulturalist or fruit-grower, where appearances can be
ignored, Bordeaux mixture is at once the most effective
and cheapest fungicide that can be used.

As a typical illustration of the value of spraying with
Bordeaux mixture, the following is taken from Bulletin
No. 7 of the United States Department of Agriculture,
entitled, ' The Effect of Spraying with Fungicides on the
Growth of Nursery Stock.'

Seedlings or grafted stocks of pears, cherries, plums,
apples, etc., are subject to various fungous diseases which
attack the foliage, causing the latter to fall prematurely,
and as a result the following are some of the effects pro-
duced : — (i) In the case of seedlings the active wood ripens
so that the buds cannot be inserted, or if they are inserted
the union with the stock is imperfect, and in consequence
the bud eventually dies; (2) if the bud or graft should
grow, its development is checked by the annual early loss
or drying-up of its leaves. This brings about a stunted
development, from which it is doubtful if the tree ever
recovers.

The experiments were conducted on a large scale, and
continued for three consecutive years, each tree being
sprayed five times each year. An equal number of un-
sprayed trees, growing under similar conditions, afforded
the basis from which the following conclusions were made.

The cost of treating nursery stock with Bordeaux
mixture, the only preparation that can be unqualifiedly
recommended, need not exceed 25 cents per 1000 trees
the first season. The second year the cost of the work

36 PLANT DISEASES

will be also 25 cents, while the third year the cost will be
increased to 35 or 40 cents per 1000, making the total
cost of treating trees until the buds are two years old from
85 cents to $i per 1000.

The net profit resulting from the work in case of the
pears and cherries ranged from $i to $40 per 1000 trees,
the average being $13 per 1000.

In conclusion, it may be said that as a whole the
experiments clearly show that spraying nursery stock with
fungicides is thoroughly practicable; that it results in
better trees ; and finally, that it yields a handsome profit.

AMMONIACAL SOLUTION OF COPPER CARBONATE

Water . . . .16 gallons.

Carbonate of copper . i ounce.

Carbonate of ammonia . 5 ounces.

Mix the carbonate of copper and the carbonate of

ammonia, and dissolve it in about a quart of hot water.

When thoroughly dissolved, add 16 gallons of cold water.

A second method of preparation, as follows, is recom-
mended by Professor Galloway : —

Water . . . .45 gallons.
Strong aqua ammonia . 3 pints.
Copper carbonate . . 5 ounces.

The copper carbonate is first made into a thin paste by
adding a pint and a half of water. The ammonia water
is then slowly added, and if of the proper strength, i.e.
26 degrees, a clear, deep blue solution is obtained, which
does not become cloudy when diluted to 45 gallons.

This preparation, being a perfectly clear liquid, can be

FUNGICIDES 37

used in greenhouses and elsewhere, where, for reasons
already stated, Bordeaux mixture could not be applied. It
is especially useful against the large group of parasitic fungi
having superficial mycelium — Perisporiaceae — including
such pests as rose mildew (Sphaerotheca pannosa\ and
hop mildew {Sphaerotheca castagnei). It may also be
generally used where the object is to check the spread of
a disease extending by means of conidia.

POTASSIUM SULPHIDE SOLUTION

Water .... 2^ gallons.

Potassium sulphide . i ounce.

Dissolve the potassium sulphide, popularly known as
liver of sulphur, in a quart of hot water, then make up to
2\ gallons with cold water. This is also a clear liquid,
and like the former can be easily used without any clogging
at the nozzle of the sprayer. It is useful for checking the
spread of an epidemic, and has proved successful against
the chrysanthemum rust (Pucdnia hieracii).

IRON SULPHATE SOLUTION
Water . . . . 50 gallons.
Sulphuric acid . . i pint.

Iron sulphate . . .25 pounds.

Pour the sulphuric acid upon the iron sulphate, and
then add by degrees the 50 gallons of water. A metal
vessel must not be used for the preparation of this mixture,
as it would be acted upon by the sulphuric acid ; a barrel
is the best to use.

This preparation may be used with great advantage in

38 PLANT DISEASES

those cases where a disease has previously existed, as it
destroys resting-spores that may be concealed in crevices
of bark, brickwork, or on the ground under fruit trees.

In spraying fruit trees, vines, etc., the trunk and branches
should be thoroughly drenched ; but it is all-important to
remember that the spraying should be done during the
winter, or at all events some time before the leaf-buds
begin to swell, otherwise the foliage would be completely
destroyed.

This preparation should not under any circumstances
be applied to leaves or fruit.

PERMANGANATE OF POTASH SOLUTION. — This is the well-
known liquid called ' Condy's Fluid.' However, the most
economical method is to buy the potassium permanganate
in the form of -crystals, which dissolve quickly in water.
The solution should be pale rose colour, and has proved
of use in arresting the spread of various kinds of rust. For
instance, if the leaves of seedling hollyhocks attacked by
rust (Puccinia malvacearuui) are sponged with this solution,
the disease is checked ; rusted carnations also benefit by
being sponged, or, if circumstances admit, submersed in
the solution. Potassium permanganate is too expensive
for use in spraying on a large scale ; besides, the solutions
previously mentioned are more effective. On the other
hand, it may be used in small gardens or for greenhouse
plants with advantage.

SULPHUR. — This is used as a dry powder, in the finely
precipitated condition known as ' flowers of sulphur,' and
has been in vogue for many years previous to the discovery
of liquid fungicides. It is most effective against the fungi
popularly called mildews, belonging to the Perisporiacene,
where the mycelium is entirely superficial, usually forming

FUNGICIDES 39

a more or less dense white felt on the surface of living
leaves, as the hop mildew (Sphaerotheca castagnei).

The finely powdered sulphur is dredged on the leaves
from a vessel resembling a large pepper-pot, or blown on
by means of specially contrived bellows or other apparatus ;
or frequently the primitive method of enclosing the sulphur
in a coarse canvas bag fixed to the end of a pole, which
serves as a handle, is used as a dredger. The leaves
should be damp when the sulphur is applied.

In some instances better results follow when finely
powdered quicklime is mixed with the sulphur, taking care
to always have an excess of sulphur. Quicklime may also be
laid on the ground in the spring under perennial plants that
have suffered from disease and where sclerotia or other rest-
ing forms of reproductive bodies fall to the ground, as the
products of germination are frequently killed by the lime.

Many other fungicides have been recommended for
special diseases, and their application might possibly be
extended with advantage in many instances.

As the result of numerous experiments made with the
object of checking the destructive sooty mould infesting
orange and other citrous fruits, Mr. Webber, a member
of the U.S. Department of Agriculture, strongly recom-
mends the following, known as the resin wash : —
Resin . , . .20 pounds.
Caustic soda (98 p.c.) . 4^ pounds.
Fish oil, crude . . 3 pints.

Water, to make . . 15 gallons.

Boil the resin, caustic soda, and fish oil mixed with
water until the resin is dissolved, then make up to fifteen
gallons with water. This is the stock solution. To use,
add nine parts of water to one part of the stock solution.

40 PLANT DISEASES

An American correspondent states that carnation rust
can be arrested by spraying with a solution consisting of
one ounce of arsenic dissolved in a little alcohol, and
mixed with 100 gallons of water. Care is required on the
part of the operator, on account of the poisonous nature of
the active ingredient.

Paraffin, a wine-glassful to two gallons of water, is
stated to have checked the spread of the chrysanthemum
rust (Puccinia hieracii); possibly other rusts would suc-
cumb to similar treatment, which is in other respects not
at all injurious to plants.

JENSEN'S HOT- WATER TREATMENT FOR WHEAT AND OAT
SMUT. — This method, which experience has proved to be
highly satisfactory, is reproduced as given in the latest
and most approved manner by Swingle, in the Year-Book
of the U.S. Department of Agriculture for 1894: —

' Provide two large vessels, preferably holding at least
20 gallons. Two wash kettles, soap kettles, wash boilers,
tubs, or even barrels, will do. One of the vessels should
contain warm water, say at 110° to 120° F., and the other
scalding water, at 132° to 133° F. The first is for the
purpose of warming the seed preparatory to dipping it
into the second. Unless this precaution is taken it will
be difficult to keep the water in the second vessel at the
proper temperature. A pail of cold water should be at
hand, and it is also necessary to have a kettle filled with
boiling water from which to add from time to time to
keep the temperature right. Where kettles are used, a
very small fire should be kept under the kettle of scalding
water. The seed which is to be treated must be placed,
half a bushel or more at a time, in a closed vessel that
will allow free entrance and exit of water on all sides. For

FUNGICIDES 41

this purpose there can be used a bushel basket made of
heavy wire inside of which is spread wire netting, say
12 meshes to the inch ; or an iron frame can be made at
a trifling cost, over which the wire netting can be stretched.
This will allow the water to pass freely and yet prevent
the passage of the seed. A sack made of loosely woven
material, as gunny sack, can be used instead of the wire
basket. A perforated tin vessel is in some respects pre-
ferable to any of the above. In treating stinking smut
of wheat, the grain should first be thrown into a vessel
filled with cold water; then, after stirring well, skim off
the smutted grains that float on the top, and put the
grain into the basket or other vessel for treatment with
hot water. This skimming is entirely unnecessary with
other grains, and even with wheat when only affected by
the loose smut. Now dip the basket of seed in the
first vessel containing water at 110° to 120° F. ; after a
moment lift it, and when the water has for the most part
escaped, plunge it into the water again, repeating the
operation several times. The object of the lifting and
plunging, to which should be added a rotary motion, is
to bring every grain in contact with the hot water. Less
than a minute is required for this preparatory treatment,
after which plunge the basket of seed into the second
vessel, containing water at 132° to 133° F. If the ther-
mometer indicates that the temperature of the water is
falling, pour in hot water from kettle of boiling water
until the right degree is maintained. If the temperature
should rise higher than 133°, add a little cold water. In
all cases the water should be well stirred whenever any
of a different temperature is added. The basket of seed
should very shortly after its immersion be lifted and

42 PLANT DISEASES

drained, and then plunged and agitated in the manner
described above. This operation should be repeated
six or eight times during the immersion, which should
be continued ten minutes. In this way every portion
of the seed will be subjected to the action of the
scalding water.

'After removing the grain from the scalding water,
spread on a clean floor or piece of canvas to dry. The
layer of grain should not be over 3 inches thick.

' The important precautions to be taken are as follows :—

(1) Maintain the proper temperature of the water (132° to
J33° F.), in no case allowing it to rise higher than 135° F. ;

(2) see that the volume of scalding water is much greater
(at least six or eight times) than that of the seed treated
at any one time; (3) never fill the basket or sack con-
taining the seed entirely full, but always leave room for
the grain to move about freely; (4) leave the seed in
the second vessel of water ten minutes.'

RESIN COMPOUND. — Professor Webber gives the following
formula : —

Resin 8 pounds.

Sal soda . . . .4 pounds.
Water i quart.

After boiling, add sufficient water to make five gallons
of stock solution.

Place the resin and sal soda in a comparatively large
kettle with one quart of water. Boil, meanwhile stirring
briskly, until the resin and sal soda are thoroughly melted
together and form a frothy mixture without lumps. Now
add about four gallons of cold water, pouring it in rather
slowly and with short intervals between to avoid chilling
the mixture too suddenly. When all the water has been

FUNGICIDES 43

added, bring to a boil, then pour out the hot solution,
straining it through a coarse cloth, and add sufficient
water to make exactly five gallons of the solution. This,
if correctly made, forms a thick, dark brown, translucent,
syrupy solution, which may be preserved as a stock
solution.

For use in treating the sooty mould following the white
fly (Aleyrodes dtri\ dilute this stock solution in the pro-
portion of one part to seven parts of water. — Proc. Ninth
Ann. Meeting Florida State Hort. Soc., 1896.

FUMIGATION WITH HYDROCYANIC ACID GAS. — Fumiga-
tion may be accomplished by placing over the tree a tent
of some closely woven material, as 8-ounce duck or
drilling. This should be oiled and painted black if the
treatment is to be made in daylight. The edges of the
tent are held down by a few shovelfuls of earth. For
generating the gas, fused 98 per cent, potassium cyanide,
commercial sulphuric acid, and water are used, in the pro-
portion of i ounce (avoirdupois) of potassium cyanide
to i fluid ounce of sulphuric acid and 2 fluid ounces
of water. To give the proper concentration of gas, the
quantities to be used vary somewhat with the size of
the tree. It is estimated that each 180 cubic feet of
space enclosed in the tent will require about i ounce
of potassium sulphide and the other materials in pro-
portion. The water and sulphuric acid are placed
together in an earthen vessel in the order named,1 and
the vessel is placed under the tent. The potassium
cyanide is then dropped in, and the operator quickly

1 To avoid explosions, the sulphuric acid should always be poured
slowly upon the water instead of pouring the water on the sulphuric
acid.

44 PLANT DISEASES

withdraws from the tent and closes the opening. Care
must be exercised in applying this method of treatment,
as the potassium cyanide and the gas generated are
poisonous. — Webber, U.S. Dept. Div. Veg. Phys. and
Path., Bull. No. 13.

STERILISING SOIL. — As already stated, it often happens
that where large numbers of plants are grown in a limited
space, and consequently crowded, a wave of disease
spreads rapidly, not unfrequently destroying the entire
crop.

When this occurs in houses, the most certain method
for preventing a reappearance of the disease, especially
if it is intended to continue growing the same kind of
crop, is to remove the whole of the soil, thoroughly
sterilise the building from top to bottom with a solution
of iron sulphate, and put in fresh soil.

Where the disease is due to a root parasite, as in the
'sleeping' disease of tomatoes, this method is undoubtedly
the most reliable, and in the end least costly.

However, practical men state that this method is not
always practicable; consequently the next best thing to
do is to sterilise the soil — that is, endeavour to destroy
all the mycelium, resting-spores, sclerotia, etc., that may
be present.

This can be effected with more or less certainty —
depending on the thoroughness with which the work is
done — by various methods.

Thoroughly mixing the soil with quicklime, where the
crop will admit ; or watering with a solution of soluble
phenyle, or with a liquid known in the trade as Jeyes'
fluid. The proportions for either of the two last men-
tioned substances are, one ounce to a gallon of rain-water.

FUNGICIDES 45

The soil should be thoroughly wetted through, and
allowed to remain for a week before anything is sown
or planted.

The above solutions may also be applied with benefit
where fungi, as Armillaria mellea, and other root parasites
appear around the roots of trees, etc.

Mr. G. Abbey, a constant contributor to the Journal
of Horticulture and Cottage Gardener on the subject of
plant diseases — to whom, I am afraid, I am too selfish
to admit the full extent of my indebtedness for the
numerous practical hints on the various diseases to which
plants are subject, the outcome of many years of experi-
ence— suggests the following as remedies against eelworm,
mites at the root, and wireworm : —

'Dress the land in the spring, just before sowing
seeds or setting plants, with nitrate of soda, if Ibs. per
rod, 2\ cwt. per acre, having it crushed fine, and evenly
distributed when the ground is moist, but with a prospect
of fine weather or only slight showers for a few days. This
will kill slugs and leather-jackets, as well as eelworms,
root mites, and wireworms.

'Kainit, also crushed fine, may be used similarly to
the nitrate of soda at the rate of 2\ Ibs. per rod, 3^ cwt.
per acre. In using these substances separately there is
danger of getting too much growth in the plant from
the nitrate of soda, and too little, if not some retardation,
by the use of the kainit ; and in cases of land broken up
from old pasture, or badly infested with grubs and wire-
worms, the quantities separately are not only insufficient,
but not the correct thing for the crop, say potatoes. In
that case, if cwt. of nitrate of soda and 3^ cwt. of
kainit, mixed, per acre, or 3^ Ibs. per rod, will give a

46 PLANT DISEASES

good account of the parasites the land contains, and
produce excellent results in the crop. Half the amount
of this mixture suffices on ordinary land, and is just as
good for tomatoes as for potatoes.'— Journ. Hort. and
Cott. Gardener, July 25, 1895.

The above is introduced for the reason that when applied
to tomatoes, the crop invariably remained untouched by
fungous parasites.

POISONOUS PROPERTIES OF FUNGICIDES

From time to time the serious question as to the
advisability of using fungicides, more especially Bordeaux
mixture, on account of their poisonous properties, has
been discussed, and the tone at one time assumed seemed
likely to deal a death-blow to their use.

The two leading points in the discussion were: (i)
danger to human life by partaking of fruit sprayed with
Bordeaux mixture; and (2) injury to the soil caused by
the constant application of the same solution.

The subject has been investigated, either directly or
indirectly, by leading European and American chemists,
and the verdict is that there is no risk whatever in par-
taking of fruit that has been sprayed, provided the pre-
cautions given below are observed, and that the soil is
in no way injured by the quantity of the mixture it
receives.

The important points to be kept in view in spraying
fruit with Bordeaux mixture are, to decrease the strength
of the solution as the fruit approaches maturity, and to
cease spraying altogether some little time before the
fruit is fully ripe. Lettuce and similar crops that mature

ECONOMIC CONSIDERATIONS 47

quickly should not perhaps be sprayed with Bordeaux
mixture.

This subject is fully discussed, and accompanied by a
voluminous quotation of literature bearing on the subject,
by Dr. Fairchild, in Bull. No. 6, U.S. Department of
Agriculture.

ECONOMIC CONSIDERATIONS

In attempting to furnish statistics bearing on the subject
of loss owing to plant diseases, or the gain resulting from
the use of preventive and remedial measures in combating
these pests, it is with regret we have to admit the fact
that it is necessary to search the literature of other nations
for information.

In Tubeuf and Smith's Diseases of Plants (Engl. ed.),
p. 84, we find the following account : —

1 In the Zeitschrift fur Pflanze.nkrankheiten, 1893, the
International Phytopathological Commission gave, from
estimates furnished by the Prussian Statistics Bureau, a
review of the losses in Prussia from grain rust. Amongst
other estimates we find that in 1891 the wheat harvest
of Prussia reached a total of 10,547,168 doppelcentner
(i doppelcentner = 100 kilogramme), which at 22 marks
per d.c. = ;£i 1,459,690 sterling. Of this 3,316,059 d.c.,
or ;£3>593> 75^ was depreciated by rust. The rye harvest
was 30,593,758 d.c. at 22 marks, of which 8,208,913 d.c.,
or ;£8, 896,364, was depreciated by rust. Oats reached
32,165,473 d.c. at 16 marks, of which 10,325,124 d.c.,
or ^8, 1 38,023, falls to be deducted on account of rust.
Thus on the crops, wheat, rye, and oats, the loss reached
the sum of ^20,628,147 sterling, or almost a third of

48 PLANT DISEASES

the total value 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.

1 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 emphasise the importance of
remedial measures. It must also be borne in mind that
the use of diseased fodder, especially hay, grass, or grain,
infested by rust or smut fungi, is productive of serious
results to the various animals of the farm ; while the use
of meal or flour contaminated with smuts, stinking-smuts,
or ergot, is dangerous to mankind.'

Professor Newton B. Pierce, U.S. Department of Agri-
culture, Farmers' Bulletin No. 30, writes as follows on
the subject of ' Grape Diseases on the Pacific Coast ' : —

'As near as can be learned, the disease first appeared
in 1884; in 1885 many vines were killed, and in 1886
extensive vineyards were destroyed by it in the vicinity
of Anaheim, Cal. From this time on the disease spread,
until now the whole vine-growing regions are denuded
and the disease is at work 50 miles from the point where
it began its ravages. Up to the present time, as before
stated, 30,000 acres of vines have been destroyed, causing
a direct and indirect loss of not less than $20,000,000.'

The above quotations indicate the extent of injury
done by fungi and other enemies, and undoubtedly the
unwritten experience of others who have suffered, if

ECONOMIC CONSIDERATIONS 49

recorded, would furnish evidence of losses of equal or
even greater magnitude. I have been informed that
sometimes ^"200 is lost through disease in a single
tomato-house in Guernsey.

It is in new countries, where cultivators of plants are
comparatively free from the trammels of prejudice, and
do not everlastingly confront you with the statement
that their forefathers did not have recourse to remedial
measures for the prevention of disease, that we look for
corroboration or refutation of the supposed efficacy of
the means advocated for arresting the progress of plant
diseases.

For information on this point we naturally turn to
the United States, where the subject has been more
thoroughly and universally investigated — not in a rule-of-
thumb manner — by highly qualified scientific men, located
in every part of the country, for a longer period of time
than in any other country in the world. The fact that
spraying plants for prevention of disease is now univer-
sally recognised and practised in the United States, proves
that the State did not commit a mistake in affording
every facility for the development and continuation of
such research.

The following extract is from a report by Professor
B. T. Galloway, Chief of the Division of Vegetable
Pathology, U.S. Department of Agriculture : —

* Mr. D. M. Wyngate has a large vineyard near Marl-
borough, New York, and at my request has furnished a
careful estimate of the profit derived the present season
from treatments suggested by this Division. His vine-
yard contains 7450 Concord and 1000 Delaware vines.
The vineyard last year was not treated, and yielded

D

5o PLANT DISEASES

19,690 pounds of fruit, which sold for $625.87. This
year the same vineyard was treated seven times, as
follows : —

' (i) March i, simple solution of copper applied to canes
and posts.

' (2) Just before blossoming, with Bordeaux mixture B.

'(3) Just after the grapes had formed, with Bordeaux
mixture, same as 2.

1 (4) July, same as 2 and 3.

'(5, 6, and 7) At regular intervals between July 10 and
August 25, with eau celeste.

' The total cost of the foregoing treatment, including a
Eureka sprayer, was $112.52, divided as follows: —

Eureka sprayer, . . . $21.50
Material, . . . .38.52
Labour, . . .52.50

The yield of fruit this season was 53,430 pounds, which
sold for $2181.39. Thus it will be seen that the yield
for 1890 (treated) exceeded that of 1889 (untreated) by
33)74° pounds, while there was a net increase in the
profits of $1555.52.

' Turning now to another class of plant diseases, we will
give the results of a series of experiments personally con-
ducted the past two seasons in the nurseries of Franklin,
Davis, and Co., near Baltimore. In the spring of 1889
this firm set out a block of 50,000 pear seedlings with
the expectation of budding them the following July. As
a rule seedlings of this kind are attacked by leaf blight
(Entomosporiuni maculatum, Le*v.) as soon as the foliage
appears, and in consequence it is a rare thing that more
than half of the buds take. In the hope of saving the

ECONOMIC CONSIDERATIONS 51

foliage, the Bordeaux mixture was applied seven times
during the season at a total cost of $60, and as a result
less than one-tenth of i per cent, of the buds failed to
take. This year the same treatment was continued at an
additional expense of $60. Many of the buds have
made a growth of 10 feet during the season, and as the
block now stands it is worth fully $7000. From control
experiments and from the experience of previous years,
it is safe to say that this amount is fully double what the
trees would have been worth had they been left untreated.
These facts are sufficient to bring out clearly the point
we wished to make, namely, that spraying for plant dis-
eases can be done at a handsome profit. In the light
of our present knowledge the work must be regarded as
a legitimate part of one's business. In other words, the
farmers, gardeners, and fruit-growers who neglect such
work at the present day are as much to blame for short
crops as those who fail to perfectly manure and cultivate
the soil/

SPRAYING

There is a difference of opinion amongst experts as to
the relative efficacy of a very fine, as compared with a
somewhat coarse, spray. With cyclone and eddy-chamber
nozzles, it is possible to throw a spray so fine that it hangs
like a mist in the air and does not fall to the ground.
Such fine spray is best for indoor work, but it is not so well
adapted as a somewhat coarser spray for ordinary outdoor
operations, except when the material to be sprayed is low
and easily reached, in which case a fine spray is most
economical and effective, as there is less waste of material,

52 PLANT DISEASES

it being possible to reach with certainty the exact portions
desired.

On the other hand, a very fine spray does not readily
reach the tops of fruit or other trees, consumes more time
in application, and much is wasted by wind driving the
spray in a wrong direction.

Again, if the spray is too coarse, i: forms drops which
either roll off the foliage, or, if they remain, injure the
leaves by producing a scorched appearance.

The various devices for spraying are numerous, ranging
from the hand syringe, useful for spraying in houses, to
huge steam-power contrivances carrying a tank holding
100 gallons or more of solution, and forcing a spray to
the top of a large tree. Perhaps the most generally useful
form is the barrel pump, intended to be fixed to a good
cask mounted on a wheel-barrow.

I have seen very effective spraying done with a simple
bucket-pump costing half-a-crown, the nozzle consisting of
two flat, parallel pieces of tin, the outlet being narrowed
by hammering until a spray of the required degree of
fineness is produced.

If Bordeaux mixture is used, some arrangement, auto-
matic or otherwise, should be present to keep the solution
uniformly mixed, otherwise one portion of the spray will
be too diluted to effect the desired object, and another
portion so concentrated as to injure the foliage.

Although the first cost is greater, it proves most eco-
nomical in the end to have all the pump fittings made of
hard brass formed of copper and tin. Soft brass com-
posed of copper and zinc should be avoided, as it is
corroded by ammonia.

In spraying plants, it must be remembered that efficacy

SPRAYING 53

does not turn on the amount of solution poured over a
plant, but on the amount of the solution that adheres to
the foliage, therefore the periods indicated for a renewal
of the operation must of necessity be modified according
to circumstances. A heavy rain following spraying would
wash off the greater portion of the fungicide at once,
and to wait for ten days before repeating the spraying
under such circumstances would evidently be courting
disaster.

It has been suggested that mixing a small quantity of
dessicated white of egg or dried blood with a fungicide
greatly adds to its adhesive property.

When fruit is commencing to ripen, spraying should
cease, otherwise the fruit is liable to become spotted, and
its market value consequently depreciated.

Lodeman, The Spraying of Plants^ Macmillan and Co.,
1896.

FUNGI

PHYCOMYCETES

SEEDLING CABBAGE DISEASE

(Olpidium brassicae, Dang.
=• Chytridium brassicae, Wor.)

Young cabbage plants are frequently destroyed by this
fungus when growing in damp, shady places. The stem
is attacked and the plant droops, and then falls over
and dies.

The fungus consists of a single cell, and sometimes two
or three are located in one of the cells of the host. The

54 PLANT DISEASES

fungus emits a long tube which passes through the tissue
of the host, and through this tube the zoospores formed in
the fungus cell escape, and inoculate other plants. Thick-
walled, warted resting-spores are also present in the epi-
dermal cells of the host.

PREVENTIVE MEANS. — Dry, airy localities should be
selected for seed-beds. Where the disease has existed,
the ground should not be used for the same purpose for
some time. Remove and burn dying plants to prevent
the resting-spores remaining in the soil.

Woronin, Rungsh. Jahrb. 1878, p. 557, pi. 31, figs. 12-16.

'DAMPING OFF9

(Pytkium de baryanum, Hesse.)

The term 'damping off' is applied to a disease of seed-
lings, characterised by the falling over and dying of the
plantlets, due to the destruction of the fundamental tissue
of the stem just above ground by a fungus called Pythium
de baryanum. Seedlings of cruciferous plants are more
especially attacked, but it also attacks maize, millet, clover,
mangel, cucumber, and has been recorded as occurring on
the prothalli of Ly top odium and Equisetum. Conidia,
sporangia, and sexually produced oospores are formed by
the fungus, but never in the tissues of the host, always on
its surface, or on the adjoining soil, if sufficiently wet.

The conidia form one or two germ tubes almost immedi-
ately after they are mature ; or, under certain circumstances,
after a longer or shorter period of time, even extending to
several months. A second kind of conidia require a period

DAMPING OFF

55

of rest before germination takes place. The sporangia
possess a single tubelike projection into which the proto-
plasm passes and forms a sphere at its tip, which breaks
up into biciliate zoospores.

Fig. 4. — Pythium de baryanum. i, seedlings of cress (Lepidium
sativum} attacked by the fungus ; 2, mycelium bearing conidia at the
tips of the branches, X 300 ; 3, sporangia in different stages, also a free
zoospore, x 300; 4, an oosphere, with the antheridium or male organ,
which has pierced the wall of the oosphere and inserted a slender tube,
for the purpose of allowing the contents of the antheridium to mingle
with those of the oosphere. After this blending of the contents of the two
organs, the oosphere becomes enclosed in a thick wall, to 'form the
oospore or sexually produced resting-spore, x 300; 5, a germinating
conidium, x 300.

Both oospores and resting conidia remain on the ground
and produce zoospores after a period of hibernation.

56 PLANT DISEASES

PREVENTIVE MEANS.— This disease only occurs where
the ground is very wet and the light dull. If seed beds
are formed where the drainage is good, and a fair share of
sunshine allowed, the fungus is completely held in check,
as its reproduction and diffusion depend entirely on the
constant presence of water in the soil.

De Bary, Bot. Ztg. 1881, p. 357, Tab. 5, figs. 1-7.

Marshall Ward, Quart. Journ. Microscop. Sri., vol. xxiii.
(1883), p. 487, pi. 24, figs. i-io.

Massee, Brit. Fung., p. 133, pi. 3, fig. 39.

DAMPING-OFF PROTHALLIA

(Pythium intermedium, De Bary.)

Dr. George F. Atkinson detected this fungus on fern
prothallia in the botanical conservatories of Cornell
University, U.S.A. The affected prothallia were quite
soft, limp, and darker in colour than the healthy ones.

* If the pots or vessels in which the prothallia are grown
are rested in sphagnum, a layer of which can be placed in
the bottom of the wardian case, and after the young pro-
thallia have started, all the watering be applied through
this, the prothallia will do much better than if surface
watering is practised, and far better than where the pots
are rested in a vessel partly full of water. The air of the
wardian case or of the house should not be kept too damp.'

Atkinson, Bull. 94, Cornell Univ. Agric. Expt. Station,
p. 247, i plate.

This Bulletin contains valuable information on the
life-history of other allied species, and is beautifully
illustrated.

JAPAN LILY DISEASE 57

JAPAN LILY DISEASE
{Rhizopus necans, Massee.)

During recent years a destructive wave of fungous disease
almost completely ruined the crop of lily bulbs (Li Hum
speciosum, and L. auratum) raised in Japan for exportation
to Europe.

The bulb is the part attacked, which in the earliest con-
dition shows a slight discoloration at the base when cut
open. The disease extends rapidly, the entire bulb
becoming discoloured, and finally soft and rotten.
Numerous experiments proved the disease to be caused
by a parasitic fungus called Rhizopus means. This fungus
can live as a saprophyte on the humus in the soil, and
attacks the bulbs when lifted. It is a wound-parasite,
and usually obtains access to the bulb through broken
roots.

Diseased bulbs that have become rotten show a white
weft of mycelium, from which numerous clusters of fruit
resembling miniature pins with black heads stand erect;
these are the conidial or summer fruit of the fungus.
Resting-spores are produced in the tissues of the decayed
bulb.

PREVENTIVE MEANS. — In most cases inoculation takes
place when the bulbs are taken up for exportation. If
submerged in a one per cent, solution of salicylic acid for
twenty minutes, and afterwards thoroughly dried, the
spores of the fungus are destroyed. The bulbs should be
thoroughly dry before packing, otherwise if there is the
least tendency to 'sweating,' and there happens to be any
diseased bulbs present, the disease spreads rapidly. The
fungus is presumably abundant as a saprophyte in the soil

Fig. 5. — Rhizopus necans. i, section of a diseased lily bulb, the dark portion at
the base of the bulb is the part attacked by the fungus ; 2, portion showing the
fungus in the fruiting condition, growing on the roots of a bulb, natural size ; 3,
cluster of the fruit-bearing branches of the fungus, X 5 ; 4, a cluster of the sporangeal
form of fruit, X 50; 5, diagrammatic section of a sporangium; «, columella; the
portion b, between the columella and the outer wall of the sporangium, is filled with
co/iidia; 6, spores, some of which are germinating, X 200; 7, spores, showing the
delicate markings on the epispore, X 700 ; 8, mature zygospore, X2ooJ 9, mycelium
of the fungus running between cells filled with starch, Xsoo (from Kew Btilletiii).

JAPAN LILY DISEASE 59

in which the bulbs are grown after the disease has once
appeared, consequently the same ground should not be
again planted with bulbs for some years. Lime or some
similar available substance would assist in freeing the soil
from the pest.

Diseased bulbs should not be allowed to lie and rot on
the soil, but should be collected and burned, otherwise the
resting-spores present in the tissues pass into the soil and
renew the disease.

Massee, Kew Bulletin •, 1897, p. 87, i plate.

Rhizopus nigricans, Ehr., is stated by Dr. Halsted —
N. Jersey Agric. Coll. Expt. Station, Bull. 76. figs. — as
causing a soft rot of sweet potatoes in America. The
fungus enters the root at points where the surface is broken,
develops especially after the roots are stored, more particu-
larly if { sweating ' takes place, thus agreeing in all essential
points as to mode of attack with Rhizopus necans, and in
all probability the remedial measures indicated under the
last-named fungus would be applicable in the present
instance.

WHITE RUST OF CRUCIFEES

(Cystopus candidus, Lev.)

This fungus has a world-wide distribution, and attacks
numerous cruciferous plants, both cultivated and wild. In
Britain it is most abundant on the common weed called
shepherd's-purse (Capsella bursa-pastoris\ attacking every
part of the plant above ground, and producing much dis-
tortion of the affected parts, which are snow-white, and
present a polished appearance at first, owing to the forma-

60 PLANT DISEASES

tion of dense cushions of conidia produced in chains
beneath the epidermis ; finally the conidia become free,
rupture the epidermis, and appear on the surface as a fine
white powder. On germination the conidia produce
zoospores which eventually germinate, and enter into the
tissue of seedlings through the stomata.

^

!J

Fig. 6. — Cystopus candidus. i, diseased leaf of cabbage; 2,
chains of conidia, x 350 ; 3, conidium germinating and producing
zoospores, x 300 ; 4, ripe oospore, x 300.

Oospores are only produced by the fungus parasitic
on shepherd's-purse when parts of the flower are
attacked.

After passing the winter in a resting condition, the
oospores liberate enormous quantities of zoospores, which
attack seedling crucifers.

WHITE RUST OF CRUCIFERS 61

The * Kerguelen's Land Cabbage' (Pringlea antiscor-
buticci), although exempt from the disease in its native
land, could not be kept in cultivation at Kew, owing to
the attacks of this parasite.

Among economic plants attacked may be mentioned
horse-radish, cabbage, radish, cress, wall-flower. The caper
plant (Capparis spinosa) also suffers.

PREVENTIVE MEANS. — Infection only takes place during
the seedling stage, hence the disease does not spread
among older plants.

Diseased plants, both wild and cultivated, should be
destroyed.

De Bary, Ann. Sci. Nat. (.#<?/.), ser. iv., vol. 20.
Prillieux, Malad. des Plantes Agric., i. p. 62, figs,
Wager, Ann. Bot., vol. x. p. 89.

Cystopus tragopogonis, Schrot. = Cystopus cubicus, De
Bary. This fungus forms white blisters on various umbel-
liferous plants, goat's-beard (Tragopogon\ scorzonera,
salsify, etc., frequently attacking all the plants in a bed,
and doing considerable injury. In this species the ter-
minal conidium of a chain differs in structure from the
remainder in having the wall thick throughout, whereas
the others have a thin wall with an equatorial thickened
band. The oospore has the epispore or outer wall densely
covered with minute warts or papillae, whereas the same
structure in Cystopus candidus is ornamented with large,
irregularly-shaped warts.

62 PLANT DISEASES

THE POTATO DISEASE

(Phytophthora infestans, De Bary.)

This terrible scourge was first observed near Boston,
U.S., also in Denmark and Norway, between 1840 and
1842, and by 1845 it had spread over Europe, doing
immense damage. Although the injury done at the
present day is not so severe as during the first decade
after its invasion, it is still with us, and during damp, warm
seasons still does a considerable amount of injury. In
addition to the cultivated potato (Solatium tuberosum), the
parasite also attacks several cultivated exotic species of
Solatium, the common British wild Solanum dulcamara^
and more especially the tomato.

The earliest indications of the disease are the appearance
of small brownish blotches on the leaves ; these gradually
increase in size, followed by a curling of the leaves, and in
an exceptionally severe attack the leaves and stems become
blackened and decayed within a few days, emitting a dis-
agreeable smell. If the brown spots on the under side of
a leaf are examined with a pocket-lens, numbers of delicate
white threads will be seen, especially towards the circum-
ference of the diseased patch. Higher magnification
reveals that these delicate threads are simple or branched
conidiophores, which originate from the mycelium of the
fungus, ramifying the tissues of the leaf, and emerge singly
or most frequently in small clusters through the stomata
of the leaf, for the purpose of producing conidia on the
surface of the leaf, whence they are readily dispersed by
wind, rain, passing animals, etc. The conidia are egg-
shaped and colourless, and are produced at the tips of the
conidiophores, but when a conidium is once formed, the

THE POTATO DISEASE 63

branch or axis bearing it continues to elongate in the same
straight line, leaving the conidium apparently attached to

Fig. 7. — Phytophthora infestans. i, a cluster of conidiophores with
conidia, X 400 ; 2, a free conidium showing its contents breaking up
into zoospores, x 400 ; 3, a conidium germinating and liberating
zoospores, x 400; 4, a zoospore that has become passive and germin-
ated, X4oo ; 5, a conidium germinating by the protrusion of a germ-tube,

its side. After the branch has grown for some time, a
second conidium is produced at its tip, to be again left

64 PLANT DISEASES

behind by the continued growth of the branch above it.
This peculiar mode of reproduction is the only constant
feature that distinguishes the genus Phytophthora from
Peronospora. The conidia give origin to a number of
zoospores when placed in a drop of water, or on a damp
surface, as that of a leaf covered with dew. The zoospores
move about actively for some time in the water, and
finally settle down and emit a slender germ-tube, which
enters the tissue of the leaf through a stoma, or bores
directly through the epidermis.

Conidia that are washed by rain upon young tubers of
the potato that are exposed, produce zoospores, and these
latter infect the young potato, entering its tissues and
forming a mycelium. The mycelium of the fungus also
passes down diseased stems of the potato, and thus infects
the tubers, the mycelium either passing into a latent con-
dition until the following season, when it renews its
activity and grows along with the stems springing from
the tuber ; or it continues to grow after the potatoes are
stored, especially if * sweating' takes place, and in this
manner frequently spreads rapidly through the mass of
tubers huddled together.

The sexual mode of reproduction is not developed in
this species, hence there are no oospores or resting-spores.
The bodies once described as the oospores of this species
were proved to belong to a species of Pythium living as a
saprophyte on tubers killed by the Phytophthora.

PREVENTIVE MEANS. — Much has been written on this
phase of the subject, and the outcome is not all that
could be desired. Spraying with Bordeaux mixture has,
in the hands of many experimenters, proved beneficial,
and furthermore, apart from its action on the fungus, has

THE POTATO DISEASE 65

greatly improved the yield. Potatoes obtained from a
diseased crop should never be used as 'sets,' on account
of the probability, almost certainty, of the presence of
mycelium in the tubers.

Diseased stems, leaves, and tubers should not be allowed
to lie and rot on the ground, neither should they be
thrown into the piggery nor on the manure-heap ; — burning
is the most effectual method. The disease is most severe
where potatoes are grown in a low, damp district.

Although all known varieties of potato are susceptible
to the disease, some are much more so than others, and
endeavours should be made to secure those varieties least
susceptible to the disease in a given district.

De Bary, Journ. Roy. Agric. Soc. Engl., vol. xii., 1876.
Jensen, Mem. Soc. Agric., vol. cxxxi., 1877.
Smith, Gard. Chron., July 1875.
Marshall Ward, Diseases of Plant 's, p. 59, figs.
Prillieux, Malad. des Plantes Agric., vol. i. p. 78, figs.
(1895).

LIMA BEAN MILDEW

(Phytophthora phaseoli, Thaxter.)

A destructive disease has been described as attacking
Lima beans (Phaseolus lunatus) in the United States. The
pods are more especially attacked, less frequently the
leaves and petioles; it is not uncommon on the young
shoots.

Diseased pods show white felty patches which sometimes
extend over the entire surface ; the young shoots are also
swollen and distorted. The disease spreads rapidly.

E

66 PLANT DISEASES

PREVENTIVE MEANS. — Spraying with dilute Bordeaux
mixture.

Thaxter, Bot. Gazette, vol. xiv. p. 273, 1889.

BEECH SEEDLING MILDEW

(Phytophthora omnivora, De Bary.
Phytophthora cactorum, Schrot.)

Hartig has investigated this fungus more especially as a
parasite attacking seedlings of the beech (Fogus sylvaticd),
although, as one of its specific names would lead one to
expect, it attacks many different plants, more especially in
the seedling condition, among which may be enumerated,
Cactus, Acer, Fraxinus, Robinia, Fogopyrum, Sempervivum,
Clarkia, and various conifers.

In seedlings the appearance of dark-coloured blotches
on the cotyledons or the primary leaves indicates the
presence of the fungus ; dark lines also frequently occur
on the stem below the cotyledons, and when this is the
case, recovery is impossible ; whereas if the upper leaves
only are attacked, the plantlets may recover.

Gaps are often made in seed-beds by this fungus, which
spreads rapidly when once introduced. The spread of
the disease is favoured by damp weather, retarded by
drought.

In this species the mycelium is furnished with minute,
roundish haustoria, which pierce the cells and absorb
nourishment. Lemon-shaped, papillate conidia are pro-
duced on the surface of diseased portions. These are
carried by wind or rain to neighbouring plants, where they
germinate, enter the tissues, and thus extend the disease.

BEECH SEEDLING MILDEW

67

Sexually produced oospores or resting-spores are also
produced in the interior of diseased portions of the host.
PREVENTIVE MEANS. — Seed-beds should be freed from

Fig. 8. — Phytophthora omnivora. A beech seed-
ling attacked by the fungus. The dark stem below
the cotyledons, and the blotches on both coty-
ledons, caused by mycelium in the tissues.

shade if the disease appears, as if the young plants dry
quickly the conidia are prevented from germinating. All
diseased plants should be carefully and promptly removed.

68 PLANT DISEASES

Hartig states that the oospores retain their vitality for four
years; hence soil that has produced diseased plants should
not be used again.

Hartig, Unters. aus dem Forstbot. Institut^ 1880, p. 33,
i plate.

De Bary, Beitr. zur Morphol. und Phys. der Pilze, 1881,

p. 22.

Hartig and Somerville, Diseases of Trees, p. 38, figs.

CACAO POD DISEASE

(Phytophthora omnivora^ De Bary.)

This disease has been recognised for some years past,
but has recently become much more general and destruc-
tive to cacao pods in Trinidad. The same fungus is
probably the cause of the cacao-pod disease in Ceylon.

The symptoms of disease are a darkening of the ' shell '
of the pod, which almost invariably commences at one
end, and gradually extends over the entire surface. After
a while the fruit of the fungus shows on the surface as a
delicate white mould, often appearing first in the furrows
on the surface of the pojl.

The white mould represents the conidial form of repro-
duction, and lasts for some weeks, the numerous conidia
produced being carried by wind to other pods, which in
turn become diseased.

The mycelium of the fungus permeates and destroys the
entire substance of the pericarp or ' shell,' and often also
attacks the seeds. Numerous resting-spores are formed in
the diseased fruit, and are liberated when the tissue decays,

CACAO POD DISEASE 69

when they germinate and start the disease the following
season.

PREVENTIVE MEANS. — Spray with dilute Bordeaux mix-
ture, commencing when the fruit is quite young, and
continue at intervals as required.

Remove all diseased fruit from the trees, as when once
attacked it is valueless, and only serves to spread the
disease if allowed to remain.

Do not allow diseased fruit or * shells ' to remain on the
ground in the plantation, as the commencement of the
disease each season depends on resting-spores present in
such material.

The fungus is known to attack a large number of
different plants; and it will be important to ascertain
whether it is present on other plants in the neighbourhood
of the plantation. Seedlings are often attacked.

The disease is most abundant in low, damp situations,
or where the trees are much shaded.

Massee, Kew Bulletin, 1899.

GRAPE MILDEW

(^Plasmopara viticola, Berl. and De Toni.)

This destructive fungus is a native of the United States,
being parasitic on various kinds of wild vine met with in
that country, and also on cultivated vines. It was intro-
duced into France about the year 1878, along with
American vines that were imported to replace those
destroyed by the Phylloxera, also a pest of American
origin.

In France the poles used for supporting vines are

70 PLANT DISEASES

frequently impregnated with sulphate of copper to prevent
decay, and it was observed during the autumn of 1884
that vines supported on poles treated in this manner were
comparatively free from mildew. It is interesting to note,
in connection with the above discovery, the extension of a
rule-of-thumb practice into an important and indispensable
branch of modem horticulture, when fully explained and
utilised in a scientific or methodical and exact manner.
The value of sulphate of copper in preventing the decay
of the poles depended entirely on the property it possessed
of preventing the attacks of fungi, which would otherwise
soon have destroyed the wood. Although this explanation
was not probably known at the time, or even suspected,
until its action in arresting the growth of mildew on living
vines was observed, it must be considered as suggesting
the idea of fungicides and spraying, which at the present
day is practised with very beneficial results by all intelli-
gent plant cultivators in every country, probably least so
in Great Britain.

Mildew attacks the foliage, young shoots, tendrils,
flowers, and young fruit of the vine, but usually appears
first, and is most abundant, on the leaves, where its
presence is indicated by the appearance of pale green
or yellowish spots on the upper surface. These spots
usually continue to increase in number and size, and
gradually change to a brown colour as the tissue of the
leaf dies; finally the leaf becomes brittle and falls, often
within ten days or a fortnight of the first indication of
disease. Very frequently nearly all the leaves of a vine
are attacked, and their premature fall arrests the develop-
ment of the fruit, even if the latter is not directly attacked
by the fungus ; the tree is also so weakened that the pro-

Fig. 9. — Plasmopara viticola. i, Under surface of a vine leaf
showing patches of mildew ; 2, group of conidiophores bear-
ing conidia, x 80 ; 3, three conidia, x 300 ; 4, conidia forming
zoospores ; in a the zoospores are yet within the conidium ; in
b two zoospores have escaped from the conidium, x 300 ;
5, mature oospore or resting-spore, x 300 ; 6, an oospore
germinating and producing a conidiophore, highly mag. (after
Prillieux) ; 7, autumnal form of conidiophore bearing a few
large conidia, highly mag. (after Prillieux).

72 PLANT DISEASES

duction of an average crop of fruit the following year is
very doubtful. Soon after the appearance of the pale
patches on the upper surface of the leaf, corresponding
areas on the under surface will be found covered with a
very delicate white mildew. This is the fruit of the
fungus, which has sprung from the mycelium present in
the tissues of the leaf, and has come to the surface through
the stomata or breathing pores, to form its conidia or re-
productive bodies in the air, where they have an oppor-
tunity of being carried by wind, rain, etc., on to the surface
of other leaves, where, if conditions are favourable, they
germinate within a few hours, entering the tissues of the
leaf, and thus starting a new centre of disease. As the
conidia are produced in immense numbers, even on a
single leaf, it can be seen how rapidly the disease may
spread after its first appearance.

The conidiophores are repeatedly branched near the
tip, the conidia are oval, and produced in twos or threes
at the tips of the branches. On germination the conidia
produce zoospores, which soon become stationary and
germinate. A second form of conidial reproduction is
sometimes produced late in the season, differing from the
one already described in the much larger and fewer
conidia, which are borne on very short, sparingly branched
conidiophores. During the autumn the winter form of
fruit or resting-spores are produced in great numbers in
the tissues of diseased leaves. The tips of certain branches
of mycelium present in the leaves become swollen, and
after a sexual process of fertilisation assume a spherical
form, develop a thick, coloured wall, and remain in an
unchanged condition in the tissues of dead and fallen
leaves. If the leaves decay, the resting-spores are not

GRAPE MILDEW 73

injured, but rest on the soil until the following spring,
when they germinate, producing two or three conidiophores
similar to those growing on the leaf during summer. The
zoospores, from the conidia of these germinating resting-
spores oroospores, being carried by the wind, etc., on to the
young vine-leaves, germinate, enter the tissues, and in turn
produce the mildew or summer form of the fungus.

PREVENTIVE MEANS. — In Britain, where vines are grown
in houses, and comparatively few in number in any one
establishment, but little difficulty should be experienced in
completely arresting any outbreak of mildew. If the disease
appears, spray with dilute Bordeaux mixture as a check to
the spread of the disease, for it must be borne in mind that
when the mycelium has once entered the tissue of a leaf
it cannot be destroyed without also destroying the leaf — the
wisest thing to do, — but spraying will prevent the germina-
tion of spores on leaves that are yet healthy. In such
cases the vines should also be sprayed soon after the fruit
is set, and, if necessary, continued at intervals of a fortnight
until the fruit begins to ripen. Diseased leaves should be
removed, as they soon die, and are but of little service to
the vine, whereas, if allowed to remain, they probably
assist in spreading the disease. All fallen leaves should be
carefully collected and burned, otherwise the presence of
resting-spores in their tissues will in all probability infect
the vine the following season.

In all instances where the disease has previously existed,
it would be wise to thoroughly drench the vines, during
winter before the leaf-buds move, with a solution of sulphate
of iron.

M. Louis Sipiere, writing in the Acad. des Sri., 1895,
states that lysol, a preparation of carbolic acid, is very

74 PLANT DISEASES

efficacious against insects and fungus-spores. It is cheaper
and more easily employed than either sulphur or Bordeaux
mixture. The proportions to be used are 5 grams of lysol
to one litre of water. Three applications are necessary
—spring, early summer, and late summer.

Viala, Les Maladies de la Vigne, p. 57, figs.
Cooke, Gard. Chron^ Jan. 2, 1894.
Prillieux, Malad. des Plantes Agric., vol. i. p. 97, figs.
Massee, Gard. Chron., July 21, 1894.

LETTUCE MILDEW

(Bremia lactucae, Regel.
= Peronospora gangliformis, De Bary.)

This fungus often proves very destructive to cultivated
lettuce, especially when grown in houses, where the con-
stantly humid atmosphere favours its development. The
leaves become more or less covered on the under surface
with an exceedingly delicate white mould, turn yellow, and
die, the whole plant being stunted in growth. Chicory
and artichokes are sometimes also severely attacked, as are
also cultivated cinerarias.

The fungus occurs on many wild composite plants.

PREVENTIVE MEANS. — Dilute Bordeaux mixture checks
the spread of the disease where it can be applied, which is
not the case with lettuce. Houses that become infested
should not be again used for the forcing of lettuce for some
time, lest resting-spores in the soil inoculate the crop.

This species is very sensitive to a lowering of temperature,
and can be checked if the temperature of a house can be
suddenly lowered for a short period.

ONION MILDEW 75

ONION MILDEW
(Pertnospora schleideni, Ung.)

This well-known and destructive parasite occurs wher-
ever the onion is cultivated. The first symptom of its
presence is a small yellowish patch on one or more of
the leaves. These discoloured patches are soon covered
with a delicate white bloom, looking like hoar-frost, which
quickly changes to a greyish-lilac colour. In the mean-
time, the diseased patches extend until the entire leaf is
usually affected, which ultimately dries up and falls back.
A long neck or stalk between the bulb and the base of the
leaves is almost constant in diseased plants. The bulb is
not attacked ; but if, as is usually the case, the disease
appears early, the bulb remains very small.

If a small fragment of the delicate mildew from the
surface of a leaf is examined under the microscope, it will
be seen to resemble a miniature forest ; numerous branches
of the fungus spring from the mycelium present in the
tissues of the leaf, and push into the open air through the
stomata or pores of the leaf for the purpose of producing
spores. Each branch of the fungus, when it has passed
outside the leaf, divides into numerous branchlets, each of
which bears a spore, or reproductive body, at its tip. These
minute spores, which are produced in immense numbers,
are carried by wind or rain on to the surface of neigh-
bouring healthy leaves, where they germinate at once, enter
the tissues of the leaf, and give origin to a mycelium that
soon produces fruiting branches, which grow through the
stomata of the leaf and form their spores in the air, which
serve in turn for the infection of other plants.

A second mode of reproduction is possessed by the

76

PLANT DISEASES

fungus. Numerous globose, thick-walled bodies, called
resting-spores, are produced on the mycelium present in
the tissues of the decaying leaves. These resting-spores

Fig. 10. — Peronospora schleideni. i, a conidiophore that has
emerged through a stoma of the leaf, x 300 ; 2, free conidia,
x 3°° i 3i a resting-spore, or oospore, x 300.

do not germinate until the spring following their produc-
tion, when they inoculate the young onions and start the
disease afresh. During the winter the leaves containing

ONION MILDEW 77

these resting - spores completely decay, but the spores
remain unchanged in the soil until the return of spring.

PREVENTIVE MEANS. — In the early stage of the disease
its spread may be checked by dusting with powdered quick-
lime and sulphur, using twice as much lime as sulphur.
This is best applied with bellows, and when the plants are
damp. Spraying with sulphide of potassium — half an ounce
to a gallon of water — will also answer the purpose.

Prevention rather than cure, however, should be the
constant aim, and this can be assured if the known means
for securing it are systematically and thoroughly carried
out.

It has already been stated that the first appearance of
the disease in the spring depends on the presence of
resting-spores of the fungus, which are produced in the
leaves previously killed by the summer form of the
fungus. Therefore, relative immunity from disease depends
on the amount of care exercised in collecting and burning
all such diseased leaves. If allowed to lie on the ground
and rot, the resting-spores are set free in the soil ; and as
they retain their vitality for at least two years, there is a
constant and practically a certain danger of the disease
breaking out afresh. This may appear a tedious, and some
will say impracticable, method of preventing the disease ;
nevertheless it is certain. If practicable, onions should
not be grown on the same land more than once in three
years, as at the expiration of this period all resting-spores
present in the soil are dead. Damp and shaded situations
favour the spread of the summer, or mildew, form of the
disease.

Prillieux, Malad. des Plantes Agric., vol. i. p. 143, figs.

;8 PLANT DISEASES

COLOCASIA DISEASE

(Peronospora trichotoma, Massee.)

Colocasia escuhnta> Schott, an important food-plant in
the West Indies, is known by one or other of the follow-
ing names in the different islands: 'Cocoes,' 'Tayas,'
' Tanias,' ' Tanniers,' 'Eddoes.'

In the early stage of the disease a ' tuber ' presents a
number of yellow dots when cut across, which correspond
in position to the vascular bundles ; these become darker
in colour, and finally the entire substance, except a thin
peripheral portion, becomes blackish and decayed, but
remains fairly dry. The conidial stage of the fungus
appears on the surface, and oospores are numerous in the
decayed tissue. The disease attacks the roots after they
are lifted.

PREVENTIVE MEANS. — The roots should be thoroughly
dried, and only sound ones used for propagation. Soil
that has produced a diseased crop should not be used again
for colocasias for two or three years.

Morris and Massee, Journ. Linn. Soc., 1887, p. 45, figs.

Peronospora trifoliorum, De Bary. — This species attacks
numerous plants belonging to the Leguminosae, cultivated
and wild ; Trifolium, Lupinus, Medicago, Lotus, Coronilla,
Melilotus, Orients, etc.

The leaves become covered with a pinkish-grey down,
due to the numerous conidiophores. The conidia are
broadly elliptical, greyish-lilac. Oospores smooth, reddish
brown. When clover or lucerne is attacked, the leaves
turn yellow and fall, and the only remedy against a repeti-

COLOCASIA DISEASE 79

tion of the disease is to cut the crop before oospores are
formed.

Peronospora parasitica, De Bary. — This species attacks
numerous wild and cultivated plants belonging to the
Cruciferae. Among the latter may be enumerated turnips,
radishes, rape, cabbage, wallflower, cress, etc. Diseased
parts are covered with a very delicate white mould, and
are often distorted.

Peronospora schachtii, Fuckel. — The central young
leaves of beet and mangold are frequently destroyed by
this parasite ; and if its attack is continued, favoured by
damp weather, the plant is killed. Serious injury has
been done on several occasions to the beet crop in
France. The conidiophores form dense, greyish-lilac
patches of mildew on the under surface of the leaves,
which soon become dry and perish. Numerous resting-
spores are formed in the dead leaves, hence it is important
that all diseased plants should be collected and burned,
and not allowed to lie and rot on the ground. Alternation
of crops is the best course to pursue after the disease has
been present.

Peronospora effusa, Rab., forms delicate greyish-lilac
mouldy patches on the under surface of spinach leaves,
and when present in quantity proves very destructive, as it
spreads rapidly. It also occurs on wild plants, as goose-
foot {Chenopodium). Spraying is practically impossible in
this case, but diseased plants should be collected and
destroyed, otherwise the resting-spores formed in the
decayed soil find their way into the soil, and are liable to
infect future crops.

8o PLANT DISEASES

VIOLET MILDEW

(Peronospora violae, De Bary.)

This pest is not uncommon on the leaves of Heartsease
( Viola tricolor), and has of late years done considerable
injury to the cultivated Neapolitan violet. The under
surface of the leaves is more or less covered with a
somewhat dense, dingy, pale violet-grey felt, and later
in the season oospores are formed in the dying parts of
the host.

The fungus is most abundant during damp weather.

PREVENTIVE MEANS. — So far as I am aware, no liquid
fungicides have been experimented with. Probably
potassium sulphide spray might prove beneficial. Plenty
of air and not too much water retards the spread of the
fungus.

CUCUMBER AND MELON MILDEW

(JPeronospora cubensis, Berk, and Curt.)

Forms a very delicate white mould on the under surface
of various cucurbitaceous plants under cultivation, as
cucumber, melon, squash, etc. Often proves very destruc-
tive if allowed to run its course unchecked. Known in
the United States, and recently in England. I have also
seen the fungus on leaves of Cucurbita pepo, and Cucumis
sativa from Tokyo, Japan.

PREVENTIVE MEANS. — Spray with dilute Bordeaux mix-
ture, taking care to reach and wet the under surface of the
leaves, which is not an easy matter, but it must be done.

TOBACCO MILDEW 81

TOBACCO MILDEW
(Peronospora hyoscyami, De Bary.)

In Europe this fungus is not uncommon on the leaves
of Henbane (Hyoscyamus niger). Farlow has recorded that
it is parasitic on Nicotiana glanca in California, whereas it
occurs as a destructive parasite on cultivated tobacco in
Queensland, from whence specimens were sent to Kew for
determination as far back as 1887.

PREVENTIVE MEANS. — Spraying with dilute Bordeaux
mixture has been found effective in checking the spread
of the pest.

MAIZE MILDEW

(Peronospora maydis, Racib.)

In Java the maize or Indian corn crop suffers severely
from the attacks of a Peronospora. Young plants are
attacked ; as a rule the first two or three leaves are
healthy, later ones becoming whitish or very pale green,
and soon afterwards the plants droop and die.

The conidia emerge through the stomata. The disease
appears in twelve to eighteen days after infecting a leaf
with conidia.

It is supposed that the disease has passed from some
native grass to the maize.

PREVENTIVE MEANS. — No experiments are recorded.
Oospores present in the soil are considered as the principal
factors in infection.

Care should be exercised to prevent the disease from
F

82 PLANT DISEASES

extending to other maize-growing countries. So far as is
known, it is at present confined to Java.

Raciborski, Ber. deutschen Bot. Gesell., vol. xv. p. 475,
figs. 1-4 (1897).

ASCOMYCETES

GYMNOASCACEAE

LEAF CURL
(Exoascus deformans, Fckl.)

This parasite is very destructive to the foliage of the
peach ; the leaves of the almond are also sometimes
attacked. The disease, which is very widespread, is
popularly known as 'leaf curl,' or simply as 'curl,' owing
to the fact that diseased leaves become much curled, dis-
torted, and thickened, and of a pale yellowish green, then
rosy or purplish colour ; finally the convex portions of the
diseased leaves become covered with a very delicate whitish
bloom, which presents a minutely velvety appearance
when seen through a pocket-lens. This appearance is
caused by the fruit of the fungus, which bursts through
the cuticle, and comes to the surface of the leaf for the
purpose of enabling the spores to be diffused.

The young shoots are also often more or less swollen and
distorted by the fungus, whose mycelium is perennial in
the branches, and each season passes into the leaf-buds,
which consequently contain the mycelium of the fungus
in their tissues when they expand the following spring.
New cases of infection must necessarily arise from the
presence of spores floating in the air and alighting on

LEAF CURL 83

young leaves or twigs, but it is not definitely known in
what manner this takes place. When once attacked, a

\)

Fig. n. — Exoascus dejormans. i, two peach leaves curled
by the fungus ; 2, portion of the fungus on the surface of
a leaf; «, asci containing spores, x 300 ; 3, spores from
the asci producing secondary spores by budding. There are
at first eight spores in each ascus, but by a process of bud-
ding each spore produces numerous very minute secondary
spores, so that eventually the ascus is quite filled with
secondary spores ; x 300.

tree rarely entirely recovers, but as a rule becomes more
diseased as time goes on, owing to the spread of the

84 PLANT DISEASES

perennial mycelium, and to the infection of healthy
shoots by spores produced on the diseased portions. In
those years when the disease is especially abundant, it is
not unusual to find the trees completely divested of leaves
before midsummer. Later in the season a second crop
of leaves appear, and these are not attacked by the fungus ;
nevertheless a considerable amount of damage is done,
the crop of fruit in such cases is practically lost, and in
the autumn it is found that the wood is imperfectly
matured.

PREVENTIVE MEANS. — This is a disease which, if sys-
tematically and persistently attacked, could be well kept
in check. Diseased fallen leaves should be collected
and burned; or better, those branches bearing diseased
leaves should be pruned back beyond the point of infec-
tion, and thus get rid of the perennial mycelium, which,
if allowed to remain, follows the developing shoots year
by year. There should be no hesitation about the pruning,
as when a branch is once attacked, all beyond the point
of infection is diseased, and does not produce fruit, but
only fungus spores, which assist in spreading the disease.
I have proved by repeated observations that the mycelium
does not travel backwards from the point of infection, but
forwards ; in other words, it follows the new growth.

The disease is least abundant, or often entirely absent,
in those comparatively rare instances where a genial
spring has allowed the foliage to quickly attain its full
growth without a check, whereas it is rampant when the
leaves have commenced growth under favourable auspices,
and are afterwards checked by a sudden fall in tempera-
ture. During the temporary cessation of growth of the
leaf, the mycelium of the fungus spreads rapidly in its

« POCKET-PLUMS,' OR 'BLADDER-PLUMS' 85

tissues ; and soon after growth of the leaf recommences,
the fungus manifests its presence by causing curling and
discoloration of the tissues. On the other hand, when
evidence of the activity of the fungus has been unmis-
takable, its further course has been completely checked
by a sudden increase of temperature. The disease was
very abundant in the south of England during the season
following the exceptionally cold winter of 1894-95.

Spraying with dilute Bordeaux mixture just when the
leaf-buds are beginning to expand, and again after an
interval of three weeks, would be beneficial as a safeguard
against inoculation from wind-borne spores.

Rathay, Osterr. Bot. Ztg., 1880, No. 7 ; and in LXXXIII.
Bande der Sitzb. d. K. Akad, d. Wissensch., I. Abthl. 1881.

1 POCKET-PLUMS,' or 'BLADDER-PLUMS'
(Exoascus pruni, Fckl.)

The widespread disease of plum-trees, known in different
districts by one or other of the above names, is caused by
a minute parasitic fungus, the mycelium of which is
perennial in the host-plant, living in the tissues of the
young branches, and extending into each new growth of
the host that is formed beyond the point at which the
branch was first infected by the parasite. In this instance
the fruit alone is modified and destroyed by the fungus,
whereas in allied species the leaf is the part which serves
for enabling the fungus to develop its fruit, and expose its
spores on the outside of the host, so that they may be
readily dispersed by wind and other agents when mature.

86

PLANT DISEASES

When the flowers are formed, the mycelium of the fungus
travels from the interior of the branch bearing the flower
into the young ovary, the result of which is that instead
of developing into a normal plum, it grows, under irritating
influence of the parasite, into a deformed, useless structure

Fig. 12. — Exoascus pruni. i, portion of a branch bearing three
diseased plums ; 2, section through a diseased plum.

of variable form and size, shaped like a finger or a club, often
more or less curved and flattened, and having the surface
irregularly wrinkled or warted, at first of a yellowish colour,
afterwards becoming tinged with dingy red. The entire
structure is dry, and not at all fleshy or succulent like a

'POCKET-PLUMS,5 OR 'BLADDER-PLUMS' 87

normal plum. These bodies are also hollow, the 'stone'
containing the seed not being developed. About the
middle or end of July these malformations are covered
with a very delicate bloom which is whitish at first, but
becomes tinged with yellow at a later stage. This
apparent bloom is in reality the fruit of the fungus, and
if a fragment is examined under the microscope, is found
to consist of myriads of upright, closely packed, club-
shaped cells or asci, each of which at first contains eight
spores or reproductive bodies. These asci spring from
the mycelium buried in the tissue of the bladder-plum,
and have burst through the cuticle for the purpose of
liberating their spores in the air.

In addition to attacking various kinds of cultivated
plums, the fungus also deforms the fruit of the sloe or
blackthorn, the bullace, and the bird-cherry.

PREVENTIVE MEANS. — As already stated, the mycelium
of the fungus is perennial, hibernating in the tissues of the
young branches of the host-plant in winter, and extending
into the flower-buds so as to reach the young ovaries,
where it forms its fruit as already described. It follows
that when the mycelium of the fungus has once gained an
entrance into the tissues of a tree, external applications
are of no service; moreover, I find from a series of
observations that the fungus does not spread backwards
in the branch beyond the point of infection, but only
grows along with the new shoots. Therefore, if infected
branches are pruned back beyond the point where the
disease shows itself, it would be arrested, to the extent
due to the presence of perennial mycelium in the branches.
This pruning may be carried out without hesitation, as
diseased branches never recover and bear good fruit, but

88 PLANT DISEASES

simply go on producing fungus spores which serve for
the inoculation of healthy trees or branches. Unfortun-
ately our knowledge of the life-history of this fungus is
incomplete ; we do not know, as yet, in what manner the
spores of the fungus gain access to the plum-tree in the
first instance, neither do we know the particular part of
the tree attacked; but the sudden appearance of the
disease in districts where it was previously unknown
proves conclusively that inoculation by means of spores,
which are probably transported by wind, insects, or other
agents, does take place.

The chances of infection by floating spores can be
considerably reduced by collecting and burning all dis-
eased fruit before the fungus appears on the surface to
liberate its spores. When a tree is once infected, the
disease usually appears year after year in greater quantity
than before, and, as already stated, cure is then practically
impossible, and the wisest policy is to cut such trees down,
and replace by healthy ones.

If your neighbour's trees, over which you can exercise
no control, are diseased, it would be wise to ward off the
chance of your own trees becoming infected, by spraying
with Bordeaux mixture at intervals from the period of
the expansion of the leaves until the fruit is set.

Of course the wild trees previously mentioned as being
hosts of the parasite should not be allowed to grow, unless
for some definite reason, in the neighbourhood of plum-
trees ; and if so, should be carefully watched.

Sadebeck, Die parasitischen Exoasceen, p. 44.
Marshall Ward, Diseases of Plants, p. 107, figs.

'WITCHES' BROOMS' OF CHERRY 89

'WITCHES' BROOMS' OF CHERRY

(Exoascus cerasi, Sadeb.)

This disease, which is not uncommon on the Continent,
is rare in Britain. Cherry-trees attacked by this disease
show dense tufts of branches growing as it were from a
single point, and presenting the appearance of the abnor-
mal developments so much more abundant on the birch,
and known popularly as 'witches' brooms,' 'witches' besoms,'
'birds' nests/ etc., in different parts of the country. These
tufts never bear fruit, and the leaves produced on such
abnormal branches are thick and leathery, of a sickly
greenish yellow or tinged red, and in due course present
a hoary appearance due to the presence of the fruit of
the fungus on their surface.

PREVENTIVE MEANS.— The best way of getting rid of
the fungus, the mycelium of which is perennial in the
diseased parts, is to cut out the tufts, which not only
disfigure the tree, but continually add to the chances of
extending the disease.

The following species also occur in Britain : —

'WITCHES' BROOMS' OF SILVER BIRCH

(Exoascus turgiduS) Sadeb.)

This forms the familiar dense tufts of branches on the
silver birch.

'WITCHES' BROOMS' OF ALDER

(Exoascus amentorum, Sadeb.)

This species deforms and much enlarges the scales of
the female catkins of the alder.

PLANT DISEASES

PEAR LEAF BLISTER

(Taphrlna bullata, Tul.)

This fungus often causes irregularly shaped, thickish
blisters or swollen patches to appear on pear leaves.
Quince leaves are also stated to be sometimes similarly
attacked. The blisters are green at first, then dark brown,

Fig. 13. — Taphrina bullata. i, leaf of pear-tree with blisters
caused by the fungus ; 2, asci with spores seated on the epidermis
of a leaf, x 300.

and finally become delicately frosted on the under surface
with the fruit of the fungus, which bursts through the
cuticle. The leaves do not curl as in the 'leaf curl' of
the peach, but remain flat.

PREVENTIVE MEANS. — The mycelium is not perennial
in the branches of the host-plant in the species of Taphrina^
as is the case with the species of Exoascus, hence its

PEAR LEAF BLISTER 91

appearance year by year depends entirely on the host-
plant being infected by spores floating in the air, or carried
by some outside agency. Collecting the diseased leaves
from large trees is not practicable ; but this is an easy
matter, and well worth the trouble, in the case of nursery
stock, and is the most certain means of stamping out the
disease. Spraying with dilute Bordeaux mixture two or
three times, at intervals of a fortnight, until the leaves are
full grown, holds this, and many other pests, in check,
which are otherwise always ready to attack, and con-
sequently retard the growth of, young trees.

The following species of Taphrina also occur in Britain.
If such become a nuisance, the preventive means suggested
under Taphrina bullata will be found adequate : —

ALDER LEAF BLISTER

(Taphrina sadebeckii> Johans.)

Forms small white or yellowish patches on the under,
less frequently on the upper, surface of the leaves of
alders.

POPLAR LEAF BLISTER

(Taphrina aurea, Fries.)

Forms large golden-yellow blisters, concave on the
under surface of the leaf, convex on the upper surface, on
the leaves of different kinds of poplar.

92 PLANT DISEASES

POPLAR FRUIT BLISTER

( Taphrina johansonii. Sad eb.)

Attacks the carpels of the aspen, causing them to become
very much swollen and change in colour to a bright golden
yellow.

ELM LEAF BLISTER

(Taphrina ulmi^ Johans.)

This fungus forms blisters on the leaves of the common
elm, and on those of the wych elm. These patches are at
first dark, dingy green, then blackish-brown, and often
cover a great portion of the leaf.

PERISPORIACEAE

POWDERY MILDEW OF VINE
(Uncinula spiralis, Berk, and Curt.)

The conidial stage of this fungus has been known in
this country since 1845, when it was described by the Rev.
M. J. Berkeley under the name Oidium tuckeri. It is probably
a native of the United States, where it is common on both
wild and cultivated vines. The fungus forms white or
greyish-white patches on the upper surface of the leaves,
young shoots, and fruit. After the patches have been
present for some time, numerous short branches of the
mycelium grow erect, each branch becoming converted at
its upper part into a chain of oblong conidia. The terminal
conidium is the oldest, and when mature falls off, the one

Fig. 14. — Uncinula spiralis. i, fungus forming white patches
on the upper surface of a vine leaf; 2, part of a vine leaf with the
fungus bearing perithecia ; 3, portion of mycelium bearing erect
chains of conidia at a, a] and haustoria which send slender tubes
into the living cells of the leaf, b, b, x 300 ; 4, a single free
conidium, x 300; 5, a perithecium with its curled appendages,
x ico ; 6, an ascus containing six spores, x 300 ; 7, a free asco-
spore, x 300 ; 8, grapes attacked by the disease.

94 PLANT DISEASES

below following suit ; at the same time new conidia are
being produced at the base of the chain. This formation
of numerous chains of upright conidia gives to the patches
a minutely powdery appearance, hence the popular name.
Myriads of conidia are produced throughout the summer,
and being washed by rain on to the surface of healthy
portions of the vine, where they germinate at once, the
disease spreads rapidly.

Towards the end of summer a second and higher form
of fruit develops on the patches of conidia-bearing
mycelium, first appearing as yellow points, which finally
change to black. These bodies are called perithecia, and
are hollow spheres, containing in their interior spores pro-
duced in asci. The perithecia are provided with several
spreading appendages or branches, each of which is more
or less spirally curved at the tip. The ascospores are
liberated from the perithecia in the spring, when they
germinate and give origin to the conidial form of the
fungus. The conidial form of the fungus was the only one
known in Europe until quite recently, when the perithecia
were observed in France.

PREVENTIVE MEANS. — According to Professor Galloway,
the disease is easily checked. 'It succumbs readily to
sulphur, either in the form of flowers of sulphur, or solutions
of the sulphide. In applying the sulphur, bellows should
be used, and the first applications should be made ten or
twelve days before the flowers open, the second when in
full bloom, and a third three weeks or a month later, if the
disease seems to be on the increase. The best results are
obtained with the thermometer ranging from 80° to 100°
F. In this temperature fumes are given off which quickly
destroy the fungus. We have obtained excellent results in

GOOSEBERRY LEAF MILDEW 95

treating this disease with a solution made by dissolving
half an ounce of potassium sulphide to the gallon of water.
The preparation is cheap, and can be quickly and effec-
tually applied with any of the well-known spraying pumps.
The greatest care should be exercised in making the second
spraying, which, by the way, should be at the same time
as that mentioned for the flowers of sulphur, in order to
protect the blossoms from the fungus.'

Berkeley, Gard. Chron., Nov. 27, 18*7.
Scribner, U.S. Dept. Agric., Bull. n.

GOOSEBERRY LEAF MILDEW

(Microsphaera grossulariae. Lev.)

During certain seasons the leaves of gooseberries are
more or less covered on the upper surface with a very
delicate, whitish, powdery-looking mildew. When the
mycelium is well established on the leaf, numerous erect
chains of conidia appear. Later in the season perithecia
are produced, at first yellow, finally blackish, which contain
resting spores produced in asci in their interior. The
appendages of the perithecia are branched in a compli-
cated manner at the tip.

PREVENTIVE MEANS. — Spray with potassium sulphide
solution, commencing first when the leaves are unfolding.

HOP MILDEW

(Sphaerotheca castagnei^ LeV.)

This scourge of hop-fields is also parasitic on numerous
wild plants belonging to various Orders. It first appears

96 PLANT DISEASES

as very delicate white patches on both surfaces of the
leaves, being usually most abundant on the under side;
during damp weather the patches increase in size, often
covering the entire surface of the leaf and presenting a
mealy appearance, due to the presence of numerous white

Fig. 15. — Microsphaera grossulanae. i, gooseberry
leaf with fungus ; 2, a perithecium with its appendages,
x 75 1 3» ^P °f an appendage, x 300 ; 4, 5, asci contain-
ing spores, x 400.

conidia, which, as usual in the Erysipheae, are produced
in erect chains, the terminal ones falling off as they become
mature, young ones at the same time forming at the base
of the chain. By this method enormous quantities of
conidia are produced throughout the summer months, and

HOP MILDEW 97

being distributed, as fast as they appear, by rain, wind,
insects, etc., greatly facilitate the rapid spread of the
disease. As the season advances, the patches become
darker in colour, due in part to the presence of the
ascigerous form of fruit, the tiny perithecia being first
yellow and finally blackish-brown. Each perithecium con-
tains a single ascus enclosing eight spores. This stage
matures during the winter on the dead parts of the hop or
other host-plant; and it is due to the germinating asco-
spores in the early summer that the disease first appears.
So long as the mildew is confined to the hop leaves, but
little injury is done; but if it passes on to the inflorescence,
and attacks the young cones, serious damage may result.

PREVENTIVE MEANS. — Flowers of sulphur sprinkled over
the foliage checks the disease. Being a superficial parasite,
spraying with potassium sulphide solution or other fungicide
would probably be yet more effectual, if commenced suf-
ficiently early. Aphides and insects should be kept in
check, as these greatly assist in diffusing conidia. Weeds
should not be allowed, as the fungus is common on many
kinds, and may from thence pass to the hop.

De Bary, Fungi, Mycetozoa, etc. (Engl. ed.), p. 201.
Marshall Ward, Diseases of Plants^ p. 149, figs.

AMERICAN GOOSEBERRY MILDEW

(Sphaerotheca mors-uvae^ Berk, and Curt.)

The finer varieties of imported gooseberries have for
several years suffered severely in the United States from
the effects of a minute fungous parasite which attacks the
young leaves and buds, first appearing as a cobweblike

G

98 PLANT DISEASES

mildew, which at a later stage becomes covered with a
delicate white powder, due to the formation of myriads of
conidia. During the early summer the diseased leaves
become brown and dead. The young fruit is also attacked,
usually becoming distorted and dwarfed.

PREVENTIVE MEANS. — Spraying with potassium sulphide
has given satisfactory results ; the first application should
be made before the buds expand, and continued at intervals
often or fifteen days as required.

Halsted, Rep. U.S. Dept. Agric., 1887, p. 373.

HAZEL LEAF MILDEW

(Phyllactinia suffulta, Sacc.)

The under surface of hazel and filbert leaves is not
unfrequently more or less covered with a delicate white
mildew, which commences as scattered patches; these
under favourable conditions grow into each other and
cover the entire surface of the leaf.

Numerous minute, blackish perithecia are formed during
the summer. The appendages of the perithecia are spine-
like, straight, unbranched, and have a swollen base.

PREVENTIVE MEANS. — Similar to those given under
gooseberry leaf mildew. The fungus is also parasitic upon
the leaves of hawthorn, elm, ash, beech, birch, alder,
willow, oak, hornbeam, honeysuckle, spindle-tree, cornel,
and sea-buckthorn.

POWDERY MILDEW OF CHERRY

(Podosphaera oxyacantha, De Bary.)
This pest is more especially injurious to young cherry-
trees, but also attacks the apple, peach, quince, and other

POWDERY MILDEW OF CHERRY

99

cultivated and wild plants belonging to Rosaceae ; it also
occurs on species of Vaccinium and Diospyros.

It appears on young leaves and tender shoots as small

Fig. id.—Phyllactinja su/ulta. i, hazel leaf with
fungus; 2, perithecia, a; appendages, b\ mycelium, c\
ascus escaping from a perithecium, e, X75; 3, asci con-
taining spores, x 300.

white patches, which soon spread and run into each other,
forming a thin white felt ; both surfaces of the leaf are
attacked. Chains of conidia are first formed, and later in

ioo PLANT DISEASES

the season minute black ascigerous fruit appears; each
perithecium contains a single ascus, and near its apex
bears a cluster of almost erect appendages, with much-
branched tips.

If the fungus attacks full-grown leaves, but little injury is
done ; whereas when quite young leaves and tender shoots
are attacked, the injury is often severe.

PREVENTIVE MEANS. — Spraying with potassium sul-
phide, if commenced sufficiently early, checks the disease.
If the disease is allowed to run its course, the fallen leaves
should be gathered and burned, otherwise the ascigerous
fruit on the leaves will inoculate the trees the following
season.

Galloway, U.S. Dept. Agric. Ann. Rep., 1888, p. 352,
pi. vii.

SOOTY MOULD OF ORANGE

(Meliola — Various Species.)

The black incrustation covering the leaves, and some-
times also the fruit, is probably met with wherever the
orange is cultivated. The mycelium forms a black, com-
pact membrane on the upper surface of the leaves, which
not unfrequently cracks and peels off in patches. The
fungus is not parasitic, but appears to assimilate the
' honey-dew ' secreted by aphides and other insects, which
it almost invariably follows ; hence, if the trees are kept
free from such insects, sooty mould could not exist. The
fungus causes injury by preventing the leaves from per-
forming their functions ; fruit covered by the fungus is
also materially injured, and often rendered unsaleable.

SOOTY MOULD OF ORANGE

101

Probably no group of fungi are so imperfectly under-
stood as the black members of the Perisporiaceae, except-
ing the genus Mcliola, which has been recently monographed
by Gaillard. The sooty mould is probably caused by
different species in different countries, as shown by

Fig. 17. — Meliola sp. Sooty mould of orange and citron on
orange leaves.

M'Alpine. In Europe and the United States the disease
is generally attributed to Meliola penzigii, Sacc., and M.
camelliae, Sacc. Both these are, however, excluded from
Meliola by Gaillard, who, however, has not indicated their
affinities ; hence it is convenient for the present to use the

102 PLANT DISEASES

names already given. For the present purpose, however,
this is unimportant, as it is the insects that have to be
dealt with directly, and not the fungi.

PREVENTIVE MEANS. — Swingle and Webber have
demonstrated that ' resin-wash ' is effective, inasmuch as
it destroys the 'honey-dew' secreting insects. Spraying
should be done when the insect is in the larval or pupal
stage ; and it is important that the under surface of the
leaves be thoroughly wetted. Webber has observed that
members of a genus of fungi called Aschersonia are
parasitic on the insects forming * honey-dew,' and are
often present in immense numbers ; and sees in the
introduction and fostering of these parasites a means of
keeping the insects in check. The fungi appear under
the form of small yellowish or orange pustules on the
leaves, and such should be looked upon as friends wher-
ever observed. I have shown that species of Aschersania
— which hitherto were only known to produce a conidial
form of reproduction on living leaves — produce an asci-
gerous form of fruit, following the conidial stage, on fallen,
dead leaves; consequently such dead leaves should be
allowed to remain to produce the ascigerous fruit, and
thus further aid in the multiplication of the fungus.
Fumigation with hydrocyanic acid gas is also very effec-
tive ; treatment to last about forty-five minutes. Should
be done when the temperature is low.

Swingle and Webber, U.S. Dept., Agric. Dept. Veg. and
PhysioL, Bull. No. 8.

Webber, I.e., Bull. No. 13.

Massee, Journ. Bot., vol. vi. p. 357, pi., for description
of ascigerous stage of Aschersonia.

SOOTY MOULD OF ORANGE 103

Capnodium dtricohint^ M' Alpine. — This fungus, known
as ' Black-blight ' in Australia, appears to be widely dis-
tributed on living leaves of orange and lemon trees in
the last-named country. As is the case with allied forms,
this species appears to require the previous presence of
aphides or scale insects to furnish ' honey-dew ' for its
nourishment; consequently the mode of treatment already
given would be found effective.

M 'Alpine, Proc. Linn. Soc., N.S. Wales, 1896, p. 469,
12 pi.

MANGO BLACK-BLIGHT
{Dimerosporium mangiferum, Sacc.
= Capnodium mangiferum, Cke. and Broome.)

This fungus forms intensely black, velvety patches on
both sides of the mango leaves (Mangifera indica), some-
times entirely covering the leaf; and as the fungus spreads
quickly, owing to its varied modes of reproduction, much
injury is done to the trees. It is certain that this species,
like many other black, incrusting, non- parasitic fungi,
follows aphides, scale, or other ' honey-dew '-producing
insects ; hence the preventive means necessary are those
calculated to destroy the insects ; resin-wash being a
proved remedy.

SPHAERIACEAE

SUGAR-CANE DISEASE

(Trichosphaeria sacchan\ Massee.)

This is a wound fungus, gaining access to the interior
of the sugar-cane through the broken ends of lateral

104 PLANT DISEASES

shoots, dead leaf bases, etc., but more especially through
the wounds made by the moth-borer (Diatraea saccharalis,
Fabr.), or the shot-borer (Xyleborus perforans^ Wall.).
When the mycelium attacks the living tissues it usually
first follows the vascular bundles, which assume a bright
red colour, characteristic of the incipient stage of the
disease. Eventually two conidial forms of fruit are
produced, microconidia and macroconidia, which burst
through the siliceous cuticle of the cane, and form sooty
streaks on the surface. Finally, the ascigerous form of
fruit is developed only on very old and much decayed
canes. The disease has been most severe in the West
Indies, but has also been recorded from Mauritius, India,
Java, and Queensland.

PREVENTIVE MEANS. — When the mycelium once gains
an entrance to the tissues of a cane, it spreads through-
out its entire length. Diseased canes yield little or no
sugar, and consequently were used for propagation, being
cut into pieces about one foot long. Diseased canes
were also left lying about on the ground, affording every
facility for the spread of the disease. Now that the fields
are kept clean, and only healthy canes used for propaga-
tion, the terrific wave of disease, which for a time
paralysed the sugar industry in Barbados and other West
Indian islands, is disappearing.

Massee, Ann. Bot., vol. vii. i pi. (1893).
Went, Ann. Bot., vol. x. p. 583, pi. 26.

BLACK ROT OF GRAPES 105

BLACK ROT OF GRAPES
(Guignardia bidwellii, Viala and Ravaz.)

This fungus is probably the most destructive and wide-
spread of enemies against which viticulturalists in the
United States have to cope. The disease was introduced
into Europe along with vines imported from North
America to replace those destroyed by the Phylloxera,
itself a pest of American origin, being first observed in
France by Professor Viala in 1885.

During certain seasons the crop of grapes is much
injured in this country ; and when once established, it is
only by exercising the greatest amount of promptitude and
cleanliness that the fungus can be exterminated. As a rule,
young shoots and leaves are first attacked, the disease
appearing under the form of small brownish patches,
somewhat resembling the blotches caused by sun-scald.
About a fortnight later, the fruit shows symptoms of
disease ; small blackish or brownish spots appear at
different points on the surface ; very soon the fruit becomes
black, shrivelled, and hard, but as a rule does not drop
off. If examined with a pocket lens at this stage, the
surface of the patches will be seen to be studded with
minute black points. These points are pycnidia or summer
fruits, which produce innumerable minute bodies called
stylospores or reproductive bodies in their interior. The
stylospores ooze out of a small opening at the top of the
pycnidia in the form of slender threads, being held together
by a sticky substance ; they are however readily separated
by dew or rain, and those that happen to be carried on to
the surface of a damp grape germinate at once, enter the
tissues, and soon give origin to a diseased spot, which in
course of time produces more stylospores.

106 PLANT DISEASES

Two other forms of summer fruit are also produced by
the fungus under certain conditions.

Finally, a fourth and higher form of fruit appears on
diseased grapes that are lying on the ground during the
winter months ; in this form the spores are produced
in asci, and mature during the following spring. It is
supposed, but not yet definitely proved, that the spores of
this winter form of fruit start the disease afresh in the
spring.

PREVENTIVE MEANS. — All diseased fruit, whether hang-
ing on the vines or lying on the ground, should be collected
and burned: otherwise there is a danger, amounting almost
to a certainty, that the disease will appear during the
following season. In like manner all fruit showing the
least trace of ' spot ' or summer stage of the disease should
be promptly removed before the stylospores are ripe, so as
to check as much as possible the spread of the disease.
In those instances where the disease has previously existed,
the vines should be sprayed with Bordeaux mixture just
when the leaf-buds are expanding, and again at intervals.
After the fruit is half-grown, ammoniacal solution of copper
carbonate should be used for spraying instead of the
Bordeaux mixture, so as to avoid spotting the fruit. It
has been demonstrated in the United States that spraying
with Bordeaux mixture not only checks the disease, but also
keeps the vines healthier and more prolific than unsprayed
vines that have not suffered from the disease.

Scribner, Bot. Gaz., vol. xi. p. 297 (contains the first
account of the ascigerous form of fruit).
Viala and Ravaz., Le Black Rot, 1886.
Massee, Gard. Chron., Jan. 26, 1895, figs.

STRAWBERRY LEAF SPOT 107

STRAWBERRY LEAF SPOT

(Sphaerellafragariae, Tul.)

The leaves of cultivated strawberries are too frequently
attacked by this fungus, which is widely distributed.
Small dusky spots first appear on the upper surface; as
these continue to increase in size for some time, and run
into each other, large blotches are often formed. The
central part of each blotch changes to a pale grey or almost
white, and is bordered by a reddish line. Next, minute
white tufts of mould appear on the white central spots;
these constitute the conidial condition of the fungus —
once considered as a distinct species called Ramularia
tulasnei.

Later in the season the higher stage of the fungus
appears on the white patches, under the form of minute
black points; these are perithecia containing spores pro-
duced in asci. Minute sclerotia are also formed in the
fading leaves.

Conceptacles resembling the perithecia in form are
sometimes present, containing myriads of very minute
conidia.

The ascospores and sclerotia germinate the following
season ; the spores thus produced start the disease again.
If the leaves become badly diseased, the crop of fruit is
materially affected, if not completely lost ; moreover, the
plants become so weakened through loss of leaves that they
are comparatively worthless the following season.

PREVENTIVE MEANS. — The disease can be checked by
spraying with Bordeaux mixture. If the disease has
existed previously, spraying should commence when the
leaves unfold, and be repeated at intervals as required

io8 PLANT DISEASES

until the flowers appear. The disease is often very severe
in the United States. Professor Trelese has the following
note on its prevention: — 'The most convenient way of
effecting this is by mowing badly rusted beds soon after the
fruit is gathered, covering the dry tops with a light coating

Fig. 1 8. — Sphaerella fragrariae. i, strawberry leaf
diseased ; 2, ascus with eight spores from a perithecium
of the Sphaerella or ascigerous condition, x 300 ;
3, conidia of the Ramularia stage, x 300.

of straw, or harrowing up the old mulching, and burning
them. This may seem harsh treatment for the plants, but
it has been resorted to by many berry-growers for the
destruction of insects with most satisfactory results ; and
every one who has tried burning over a strawberry bed has

BEETROOT AND MANGEL ROT 109

been surprised by the vigorous and healthy appearance of
the new foliage which soon unfolds.'

Tulasne, Fungorum Carpologia, vol. ii. p. 108, pi. xxxi.
Prillieux, Malad. des Plantes Agric., vol. ii. p. 268, figs.

BEETROOT AND MANGEL ROT

(Sphaerella tabifica, Prill, and Del.
^= Phoma tabifica, „ „

— Phoma bctae, Frank.)

During the past few' years the beet crop in France and
Germany has suffered severely from a fungous disease.
About the month of August the largest leaves droop to
the ground, as is frequently the case during very hot, dry
weather. This drooping, however, is due to the upper
surface of the leaf-stalk having been more or less
disorganised by a parasitic fungus ; white patches, bor-
dered by an orange-brown zone, are present, often 20-25
mm. long, and finally the tissue becomes brown and dead.
This disease passes from the large leaf-stalks into the root,
penetrating to the heart, and from thence attacking and
killing the young heart-leaves. Superficial minute peri-
thecia containing numerous minute conidia, produced at
the tips of conidiophores, appear on the bleached, dead
parts of the leaf-stalk. Sometimes these reproductive
bodies are also produced on the lamina of the leaf, on
rounded patches of a pale brown colour with darker con-
centric lines. This is the Phoma stage. Later in the
season the ascigerous, or Sphaerella, condition appears on
the dead petioles, in the places previously occupied by the
Phoma. The dead heart-leaves are often more or less

no PLANT DISEASES

covered with greenish-brown velvety patches consisting
of Alternaria, Cladosporium, and Macrosporium spores ;
whether any of these are included in the life-cycle of the
Sphaerella is not yet known. Apparently the same disease
has been recorded by Dr. M'Weeney as attacking stored
mangel in Ireland.

PREVENTIVE MEANS. — As the disease appears somewhat
late in the season, it has been recommended to lift the
crop, if the disease appears, before the fungus passes from
the leaves to the root. All diseased leaves should be
collected and burned or buried, otherwise the ascigerous
condition develops on the dead parts, and a return of the
disease the following season would probably result. Great
care should be taken not to include diseased roots in
storing.

Frank, Zeitschr. fur Zuckerrubenind., 1892, p. 904; and
Zeitschr. fur Pflanzenkr.) vol. iii. p. 90, figs.

M'Weeney, Journ. Roy. Agric. Soc., ser. HI. vol. vi.
pt. 3. (1895) figs.

Prillieux, Malad. des Plantes Agric., vol. ii. p. 263, figs.
(1897).

CHERRY LEAF SCORCH

(Gnomonia erythrostoma, Auersw.)

A disease which every now and again proves destructive
to the cherry crop in various parts of Europe. The leaves
are attacked, soon presenting a scorched appearance,
withering, but hanging on the tree throughout the winter.
Long, slender, colourless, curved conidia are first pro-

CHERRY LEAF SCORCH

in

duced in perithecia seated on discoloured spots on the
leaves. During the winter, the ascigerous form of fruit is
also produced on the dead, hanging leaves.

PREVENTIVE MEANS. — All the dead, infected, hanging

Fig. 19. — Gnomonia erythrostoma. i, a diseased, dry,
shrivelled leaf that has been flattened out to show the
fungus ; 2, ascus and spores, x 300 ; 3, section through
a perithecium and portion of the leaf in which it is
imbedded, slightly x.

leaves must be collected and burned. This must, to
succeed, be general throughout the infected district.

Frank tells of one district in Prussia where this method
was carried on for two seasons, after which the cherry
crop, which had been completely ruined, was restored to
its former productiveness.

H2 PLANT DISEASES

OAK CANKER

{Diaporthe (Chorastate) taleola, Sacc.
Aglaospora taleola, Tul.)

Oak-trees are susceptible to this disease up to the age of
about forty years. Brown dead patches of the cortex indi-
cate the presence of this disease ; and as these patches are
usually of large size, and on different sides of the trunk,
the cortex is killed and the tree dies. Numerous stromata
are formed in the dead cortex ; these first bear a crop of
new-moon-shaped, or sickle-shaped, colourless conidia, and
at a later stage perithecia are formed in the black stromata.
These are flask-shaped, and the necks of two or three peri-
thecia grow together and form a single common neck or
opening, which grows to the surface. Through this neck
the ascospores pass out into the air at maturity.

The ascospores have a single median septum, from
which three spines project ; there is also a spine at each
end of the spore. Both conidia and spores are capable of
inoculating the tree, germinating first on a wounded portion
of the cortex.

PREVENTIVE MEANS. — Hartig suggests that when the
disease appears in a wood, the younger diseased trees
should at once be felled. This gives the remaining trees a
better chance of recovery, and reduces the chances of
infection caused by the friction of branches of adjoining
trees, which injures the bark ; on such wounds the spores
or conidia frequently commence their attack.

Hartig, Forstlich-naturwiss. Zeitschr., Jan. 1893.
Hartig and Somerville, Diseases of Trees, p. 99, figs.

VANILLA DISEASE 113

VANILLA DISEASE
(Calospora vanillae, Massee.)

Some years ago the vanilla industry in the Seychelles
was threatened owing to the attack of a fungus. Material
was forwarded to Kew for examination, and the pest
proved to be the fungus named above, which occurs on
the living leaves and stems as minute dull red or amber-
coloured, subtremelloid specks, springing in groups on
slightly discoloured patches. This stage of fungus agrees
with the form-genus Hainesia. As the diseased parts of
the vanilla plant ( Vanilla planifolia Andr.) wither, the
Hainesia condition is followed by a Cytispora, and finally
by an ascigerous stage. These forms are considered as
later developments of the Hainesia^ and the whole has
been named Calospora vanillae^ Massee.

The same fungus, showing all three stages, has been
received at Kew from Antigua, New Granada, attacking
the same host-plant.

PREVENTIVE MEANS. — Clearing away and burning all
diseased plants, which were allowed to lie and rot on the
ground, has resulted in suppressing the disease, which is
most prevalent in low or badly drained districts.

Massee, Kew Bulletin^ May and June, 1892, i pi

PINE LEAF FUNGUS
(Herpotricha nigra, R. Hartig.)

Abies excelsa, Juniperus communis, and J. nanus are
attacked. It is also very destructive to young larches in
elevated regions. The chocolate-coloured mycelium of

H

H4 PLANT DISEASES

this species completely invests branches and young trees
in a dense weft. The lower branches of young trees
pressed to the ground by snow are often held in this
position by the mycelium. After the leaves are killed they
do not fall to the ground but remain anchored to the
branches by the fungus, and their surface becomes covered
with a brown felt of hyphae on which perithecia are
produced in considerable numbers. The fungus is met
with in elevated regions more especially, and grows actively
under the snow.

PREVENTIVE MEANS. — Nurseries should not be formed
at high elevations, nor in valleys where the snow lies for a
long time.

Hartig, Alleg. Forst. und Jagd., Zeit. 1888.

Prillieux, Malad. des Plantes Agric., vol. ii. p. 212, figs.

SILVER FIR LEAF DISEASE

(Acanthostigma parasiticum, Sacc.
Trichosphaeria parasitica, R. Hartig.)

This fungus is abundant in young fir-woods, attacking
more especially the silver fir (Abies pectinata}^ less frequently
spruces. The mycelium is at first white, then yellowish-
brown, and covers the under surface of the branches. The
leaves are first killed, but do not fall to the ground, being
held to the branch by cobweblike mycelium. At a later
stage the twigs are also killed. In crowded woods the
mycelium passes readily from tree to tree, doing a con-
siderable amount of injury. The perithecia are formed

NEW ZEALAND WHITE ROOT-ROT 115

on a stroma developed on the dead leaves, and are
characterised by the presence of radiating brown hairs
springing from their upper surface.

The parasite is most abundant in damp situations and
where the trees are crowded. In dry, airy districts but
little harm is experienced.

Hartig, Alleg. Forst. und Jagd., Zeit. Jan. 1884.
Prillieux, Malad. des Plantes Agric., vol. ii. p. 208, figs.

NEW ZEALAND WHITE ROOT-ROT

(Rosellinia radiciperda, Massee.)

This fungus is closely allied to the European white
root-rot (Rosellinia necatrix). Mr. Allan Wight of New
Zealand describes its ravages as follows : — ' This fungus, in
the mycelial stage, attacks a great variety of tree roots,
amongst the most conspicuous of which are the apple, pear,
peach, and all other common orchard trees. The white-thorn
is also very subject to its attacks, as well as a great many
Afo'es, and several of the native trees and plants. It also
attacks the cabbage, the potato, docks, sorrel, fern, and,
in fact, is almost omnivorous. Its movements are uncertain ;
sometimes a tree here and there dies, sometimes a whole
row, and very often acres are swept off.'

The bark just underground, or the roots, are first attacked,
and presently a delicate white mycelium is seen on the
surface of diseased parts. This mycelium forms white
strands which run a few inches underground until another
victim is reached. As the disease progresses, numerous

Fig. 20. — Rosellinia radiciperda. i, Ascigerous stage of the fungus showing the
perithecia, natural size ; 2, perithecia enlarged ; 3, section of same, showing the
wall to consist of two layers ; 4, ascus containing spores, also paraphyses, X 300 ;

[Description continued on p. 117.

NEW ZEALAND WHITE ROOT-ROT 117

minute black sclerotia, which eventually give origin to a
conidial form of fruit, are formed in the cortex of diseased
portions. Next the mycelium becomes dark-coloured and
gives origin to globose, black bodies, called pycnidia, con-
taining stylospores or minute reproductive bodies in their
interior. Finally the ascigerous form of fruit is produced
on trunks or stumps that have been dead for some time.

PREVENTIVE MEANS. — Those recommended under
Rosellinia necatrix are applicable.

The following remarks appeared in the Ktw Bulletin in
connection with this disease : —

* Stagnant water should not be allowed to remain in the
soil, as this favours the spread of the fungus. Finally, in
those cases where the fungus has completely devastated
large areas, it is probable that such will be deserted as
unprofitable, the trees being allowed to lie and rot, and the
fungus to spread in the soil. This is disastrous, being in
fact a nursery for the development and diffusion of the
enemy. It is not the object of this note to suggest whose
business it is to prevent such shortsightedness, but to
impress emphatically that such a condition of things should
not be tolerated.'

Massee, Kew Bulletin, 1896, p. i, i pi.
Wight, Journ. Mycol., vol. v. p. 199.

5, tip of an ascus after treatment with a solution of iodine, showing the arrangement
for effecting the opening or dehiscence of the ascus for the escape of the spores,
X3oo; 6, ascospores, one of which is germinating, X45o; 7, brown mycelium with
swellings at intervals, XSSQ; 8, a black sclerotium bursting through the cortex of a
root, producing several clusters of conidiophores bearing conidia, X4O ; 9, a single
conidiophore bearing conidia at its branched tip, XSOQ; 10, free conidia, X 300 ;
ii, a pycnidium springing from the coloured mycelium, X4o; 12, stylospores
developed in the interior of pycnidia, XSDO. — (From Kew Bulletin.)

u8 PLANT DISEASES

WHITE ROOT-ROT

(Rosellinia necatrix^ Prill, and Del.
= Dematophora necatrix^ Hartig.)

Fortunately this scourge is rare in Britain, although too
well known on the Continent, where it attacks vineyards,
orchards, etc., in a wholesale manner. One of the marked
peculiarities of the present fungus is its power of becoming
parasitic upon a large number of plants belonging to widely
separated Orders ; in fact, it may be stated broadly that it
attacks every plant with which it comes in contact.

Hartig enumerates the following as having been destroyed
by the fungus : vines, fruit-trees, potatoes, beans, beet,
young maples, oaks, beeches, pines, and spruces. As with
Armillaria mellea^ the mycelium of the fungus under
consideration spreads rapidly underground, and when it
comes in contact with the rootlets of a plant it kills them,
and gradually works its way into the tissues of the larger
branches of the root. In the case of large plants, the
mycelium, after travelling along the tissues of the root up
to the base of the trunk, bursts through the cortex in the
form of a snow-white, fluffy mycelium, which again enters
the ground and spreads in search of fresh victims.

During the progress of the disease numerous minute
sclerotia are formed in the cortex of the diseased roots ;
and if such roots happen to be exposed to the air, these
sclerotia come to the surface and give origin to groups
of minute, bristle-like, dark-coloured conidiophores which
bear numerous conidia at their tufted tips.

A second kind of fructification sometimes occurs on
decaying roots, under the form of minute, black con-

pfc

Fig. 21. — Roselliuin necatrix. i portion of the root of an apple-tree
partly covered with white, fleecy mycelium 2, brown hypbae showing
pear-shaped swellings, X3<x>; 3, portion of an apple-tree root with sclerotia
bearing clusters of conidiophores, X6; 4, a single tuft of conidiophores,
X 70 ; 5, a branch of the last, bearing conidia, X 300 ; 6, stylospores
produced in pycnidia, X 300 (after Viala); 7, perithecium surrounded by
conidiophores, X 6 (after Viala) ; 8, ascospores, X 350 (after Viala) ; 9, a
sycamore infected with the fungus. The portion above ground is repre-
sented some fourteen days anterior to the rest. The plant is enveloped in
the white woolly mycelium, a ; on the subterranean portion Rhizoctiniae,
consisting of dark mycelium, b, b, are to be seen. Numerous sclerotia,
c, c, project from the surface. — (After Hartig.)

120 PLANT DISEASES

ceptacles called pycnidia, which produce in their interior
numerous spore-like bodies called stylospores.

As previously stated, the mycelium is at first snow-white,
but the older and exposed portions soon change to a smoky
brown colour, and develop pear-shaped swellings at intervals
throughout their length. According to Viala these swell-
ings, under certain conditions, gradually become globose,
and finally become free, and are capable of emitting a
mycelium which forms a new plant.

Finally, the highest or ascigerous condition of fructifica-
tion has been discovered by Viala ; the perithecia are com-
paratively large, black, and surrounded by the bristlelike
conidiophores already described. This last form of fruit
is rare, appearing only on trees that have been dead for
a long time, and much decayed.

PREVENTIVE MEANS. — Owing to the subterranean habit
of the fungus, spraying is out of the question, as is also a
cure when the mycelium is once established in the roots.
The soil should be well drained, as the fungus thrives best
in places that are sodden with stagnant water. If the
disease appears, affected plants should be isolated by
digging a narrow trench about a foot deep round the
trunk at such a distance as to include the main roots ; and
if roots are cut through, they should be followed and
removed. All the removed soil should be thrown inside
the trench. Trees that have been killed should be re-
moved, and special care should be exercised in removing
the stumps to get out all the roots possible, as if these are
allowed to remain they will form centres of infection from
which the mycelium will rapidly spread.

Weeds growing near to infected plants should also be
removed and burned. A method that has proved benefi-

SEEDLING OAK DISEASE 121

cial in France is to expose the base of the trunk as far
down as can be done without injury to the tree, and to
powder both trunk and surrounding soil liberally with
powdered sulphur, repeating the process at intervals.

Hartig, Unters. aus dem Forstbot. Inst. zu Munchen^ vol.
iii. pp. 95-141-

Hartig and Somerville, Diseases of Trees (Engl. ed ),
p. 82, figs.

Viala, Monog. du Pourridie des Vignes et des Arbres
fruitiers, 5 pi.

SEEDLING OAK DISEASE
{Rosellinia quercina^ Hartig.)

Hartig has described a disease which is common in
Germany, attacking the roots of seedling oaks. It presents
several features in common with the parasite called Dema-
tophora necatrix, which, judging from the mature ascigerous
fruit, as described by Viala, is also a species of Rosellinia.

The disease is most prevalent during wet seasons.
Affected plants are indicated by withering of the leaves,
and on being removed from the ground a white thread-
like mycelium, along with minute black sclerotia, are
found. These mycelial strands, which eventually become
brown, traverse the soil and attack the roots of neighbour-
ing plants.

Perithecia, producing ascospores, are also formed on
dying roots. Conidia are also formed on branches of
the mycelium running on the ground.

PREVENTIVE MEANS. — Diseased patches should be iso-
lated by a trench, to prevent the spread of the mycelium.

122 PLANT DISEASES

Dead and diseased seedlings should be removed and
burned.

Hartig, Unters. aus dem Forstbot. Inst., vol. i. p. i.
Hartig and Somerville, Diseases of Trees, p. 78, figs.

Rosellinia ligniaria^ Nitschke. — This fungus has been
observed by Mr. W. Carruthers, F.R.S., to attack living
ash-trees, eventually causing death. Specimens were
exhibited at the Linnean Society's meeting, December 16,
1897.

GUMMOSIS OF ACACIA

(Pleospora gummipara, Oud.
= Coryneum gummiparum, Oud.)

Oudemans states that the production of Arabian and
Senegal gum is due to the presence of this fungous para-
site on species of Acacia.

Oudemans, Hedwigia, 1883, pp. 131 and 161.

HYPOCREACEAE

ERGOT
(Claviceps purpurea, Tul.)

This well-known disease is often abundantly developed
in the ears of various cereals, especially rye; it also
attacks various pasture grasses.

Inoculation takes place when the plants are in bloom,
the mycelium developing in the ovary, replacing the seed.

Fig. 22. — Claviceps purpurea. i, ergot on rye- grass ;
2, ergot on rye ; 3, section of a portion of the conidial
form of fruit, X3oo; 4, a sclerotium or ergot bearing the
stalked, ascigerous form of fruit, natural size ; 5, head of
ascigerous form of fruit showing the warted surface
due to the projecting mouths of the perithecia ; also a
section, showing the perithecia sunk in the fleshy stroma ;
6, an ascus, x 300 ; 7, a single spore, x 300.

124 PLANT DISEASES

A whitish stroma forms on the surface of the ovary, having
its wrinkled surface covered with conidiophores, bearing
very minute conidia. When the conidia are mature, the
stroma becomes bathed in a sweet syrupy substance or
'honey-dew,' which attracts insects, who unconsciously
convey the conidia from one flower to another. As the
conidia germinate at once, the disease, when once intro-
duced, spreads rapidly. After the formation of conidia is
completed, the stroma continues to increase in size, and
becomes black externally, forming the hard, curved body
known as ergot, or properly, a sclerotium. Many of these
sclerotia fall to the ground, where they remain in a passive
condition until the following spring, when they give origin
to two or three stalked bodies which produce ascospores.
Some of these spores, carried by wind, alight on grass
flowers, and inoculation follows.

Apart from the direct loss of crop caused by ergot, its
action on animal life is very disastrous. Rye bread, con-
taining a considerable amount of ergot, causes a terrible
malady, characterised by gangrene of the extremities.
Abortion is also caused by partaking of the sclerotia along
with food. A wholesale epidemic of cattle in the United
States, at first considered to be the much-dreaded ' foot-
and-mouth3 disease, was proved to be caused by ergotised
food.

PREVENTIVE MEANS. — The most certain method is to
collect all the large black sclerotia possible, and, along
with those separated from the grain cleansing, either burn,
or better, sell them to a chemist for medicinal purposes.
By persistent removal of sclerotia, the first or spring inocu-
lation of grass flowers by means of ascospores is much
reduced. If, in addition to this, wild grasses growing in

REED MACE FUNGUS 125

ditches, on waste banks, etc., are kept cut, the conidial
form of the fungus is prevented from developing ; for if
this happens, conidia are almost certain to be conveyed
to cereals or pasture grasses by insects.

Tulasne, Ann. Set. Nat., Ser. in. vol. xx. p. 5, pi. 1-4

(1853).

Rep. Commis. Agric. U.S., 1884, p. 212 (for account of

effect on cattle).

REED MACE FUNGUS

(Epichloe typhina^ Tul.)

A peculiar fungus, strangling the grass on which it is
parasitic. It first appears as a whitish crust of variable
length, completely surrounding the upper leaf-sheath,
causing abortion of the inflorescence, and checking growth
above the diseased portion. When in quantity it does
considerable injury if pasture grasses are attacked, and
scarcely any species of grass is exempt from this parasite.
According to Prillieux, grass containing much of this fungus
proves injurious to horses. The stroma of the fungus is
whitish at first, and in this condition bears numerous
minute, elliptical, hyaline conidia, which are capable of
germinating the moment they are mature, and thus ensure
the rapid spread of the disease. At a later stage the stroma
becomes ochraceous and rough with the projecting mouths
of myriads of perithecia imbedded in its substance. The
asci produced in these perithecia contain very slender,
hyaline, needle-shaped spores.

PREVENTIVE MEANS. — A difficult fungus to eradicate,
as it is often very abundant on grasses in uncultivated
tracts. I once saw many acres of Agrostis canina, L.,

126

PLANT DISEASES

growing on Shiere Common, near Guildford, nearly every
plant of which was attacked by the fungus. It is often

Pig, 23. — Epichloe lyphina. i, fungus on leaf-sheath of
Holcus mollis \ 2, fungus on leaf- sheath QiHolcus lanatus ;

3, portion of fungus showing the warts on its surface
corresponding to the mouths of the.perithecia ; slightly x ;

4, section of a perithecium, x 200 ; 5, an ascus showing
the spores escaping from its apex, x 400; 6, a single
spore, X4co ; 7, conidiophores with conidia, x 300.

abundant on the grass growing on ditch banks and other
damp places, and from thence passes on to the pasture

APPLE-TREE CANKER 127

species of Poa, Holcus, Phleum, etc. If useless grass grow-
ing in damp places is cut as soon as the disease manifests
itself, its spread is much retarded.

Tulasne, Fungi SeL Carp., vol. iii. p. 24.

Prillieux, Malad. des Plantes Agric,^ vol. ii. p. 96, figs.

APPLE-TEEE CANKER

(Nectria ditissima, Tul.)

This parasite by no means confines its attacks to the
apple, but is equally common on the beech, and, according
to Hartig, also invades the oak, hazel, ash, hornbeam,
alder, maple, lime, dogwood, and bird-cherry.

The fungus is usually a wound-parasite, its conidia or
spores germinating in the first instance on some wounded
surface, and from thence invading the healthy tissues.
The bark is first attacked and destroyed, often cracking in
a concentric manner ; afterwards the wood is also destroyed,
the canker often completely girdling small branches. As
a rule a thickened, irregular margin of living bark forms
round the wound, giving a rugged appearance to the parts
attacked, and very characteristic of the disease. Not un-
frequently several diseased spots appear on a branch at
places where there is no evidence of external inoculation,
and Hartig explains this by assuming that when the fungus
has once gained admission to the living tissues through a
wound, the mycelium travels in the substance of the
branch, bursting through the bark at intervals to form its
fruit on the surface. The fungus is somewhat capricious,
not attacking the margin of the wound equally all round,
but often concentrating its work of destruction at one

Fig. 24. — Nectria ditissima. i, a branch recently
attacked, the disease entered at the axil of the small
branch ; a, a, perithecia ; 2, a branch that has been dis-
eased for some time, showing a rugged raised margin
round the wounds ; the end of the broken branch, a, is
the point where the fungus gained an entrance into the
branch ; 3, section through a stroma containing peri-
thecia, a, a, on its surface, X3o; 4, a single perithecium,
x 100 : 5, section of a perithecium, x 100 ; 6, portion of
a stroma bearing conidia, highly mag. (after Hartig) ;
7, a single conidium germinating, highly mag. (after
Hartig) ; 8, portion of the contents of a red perithecium ;
a, an ascus containing eight i-septate spores ; b, b, para-
physes, x 300.

APPLE-TREE CANKER 129

particular point, and then moving to another, resulting in
the canker spots having a very irregular outline.

At those points of the wound where the mycelium is
most vigorous, small white cushions or stromata appear in
the autumn, bearing on their surface very minute conidia,
which become free at maturity, and germinate at once.

During the following spring, a second form of fruit, con-
sisting of clusters of minute, blood-red perithecia, appear
on the cushions which during the previous autumn bore
conidia. These perithecia contain in their interior numei-
ous asci, each enclosing eight spores.

PREVENTIVE MEANS. — Badly diseased branches should
be removed and burned. Where the canker is slight the
affected part should be cut out, and the wound coated
with tar.

Hartig has observed that aphides are often present along
with the fungus, and these may assist in spreading the
disease by carrying conidia, and even unconsciously intro-
duce them into the punctures they make, hence it would
be advisable to apply an insecticide.

Old cankered fruit-trees that have been destroyed by
this or other fungi are too frequently allowed to remain
standing long after it is admitted that they are of no value,
except for firewood. Such trees are in reality acting as
nurseries for the growth and dispersion of fungus parasites,
and should be removed without delay.

Plowright, Gard. Chron., April 19, 1884, figs.
Hartig and Somerville, Diseases of Trees (Engl. ed.),
p. 91.

130 PLANT DISEASES

SPRUCE NECTRIA

(Nectria cucurbitula, Fries.)

Hartig has furnished us with an elaborate account of
this wound-parasite, of which the following is an abstract.

The spruce is most frequently attacked, rarely the silver
fir or Scots pine. Entrance to the tissue of the tree is
often through wounds made by the larva of the moth
called Grapholithj, pactolina^ also through bruises caused
by hail, or cracked branches.

The cortex is the portion most directly affected by the
fungus, although when this is killed, and especially when
it happens near the top of the tree, the wood also dries
up, and the top of the tree becomes yellow, withers,
and dies.

The mycelium is most luxuriant in the sieve-tubes of
the soft-bast, and grows most vigorously when the growth
of the tree is at a standstill. If the dead bark is almost
constantly damp, numerous whitish stromata burst through
to the surface ; these first bear conidia, followed at a later
period by crowded red perithecia containing spores formed
in asci.

PREVENTIVE MEANS. — It is considered advisable to
cut off and burn the tops of dead trees to prevent the
spread of the disease.

Hartig, Unters. aus dem forstbot. Inst. zu Munchen^
vol. i. p. 88, i pi.

Hartig and Somerville, Diseases of Trees, p. 89, figs.

CORAL SPOT DISEASE 131

CORAL SPOT DISEASE

{Nectria cinnabarina^ Fries.)

The numerous bright, coral-like warts, about the size
of a millet seed, thickly studded over the surface of dead
branches, have probably been noticed by most people at
one time or another. These are the conidial condition
of Nectria dnnabarina. The conidia are exceedingly
minute, and produced in myriads. During the autumn
and early winter, these warts assume a darker red colour,
and become minutely warted, due to the formation of the
second or ascigerous form of fruit.

The fungus often lives as a parasite, but is also a wound-
parasite, attacking various trees — sycamore, lime, horse-
chestnut, and more especially the red currant.

The spores or conidia germinate on the surface of a
wound, and the mycelium passes into the living tissue,
where it extends until a portion of the branch is killed,
when the bright-coloured fruit is formed on the surface.

PREVENTIVE MEANS. — As the mycelium spreads quickly
in the branches much beyond the point where it indicates
its presence externally, cuttings should not be taken from
diseased trees.

Diseased branches should be cut off and burned, as
should also rotten sticks lying on the ground.

Cooke, ' A Currant Twig and Something on it,' Card.
Chron., Feb. 28, 1871.

Mayr, ' Ueber den Parasitismus von Nectria cinnabarinaj
Unters, a. d. Forstbotan. Inst. zu Munchen^ vol. iii. p. i,
1883.

Durand, Cornell. Univ. Agric. Expt. Station, Bull. 125,

132 PLANT DISEASES

EGG-PLANT ROT

(Nectria ipomoeae, Hals )

The Fusarium condition causes stem-rot of the egg-
plant (Solatium melongena, L.) and sweet potato (Ipomoea
batatas, Poir.), covering the withered stems with a white
mould. At a later stage clusters of flesh-coloured peri-
thecia appear. The disease usually commences near the
ground-line, and spreads both into the stem and the root.

Halsted, Ann. ,Rep. N. Jersey Agrlc. Eocpt. Station,
1891, p. 281, figs.

Nectria vandae (Wahrlich) is a parasite on the root of
Vanda suavis in cultivation.

Nectria goroshankiniana (Wahrlich) is also parasitic on
the root of cultivated plants of Vanda tricolor.

Wahrlich, Bot. Ztg , July 23, 1886.

CACAO DISEASE

Mr. J. B. Carruthers, who has spent some time in
Ceylon investigating the destructive disease attacking the
cacao tree, has published his report, of which the following
is a summary. The name of the fungus causing the dis-
ease is not given, but the account leaves little doubt that
it is a species of Nectria^ allied to the species causing
canker in the wood of the apple-tree.

The first indication of disease is a darkening of a patch
of the cortex ; if this patch is cut out it is found to be

CACAO DISEASE 133

soft and of a claret colour and full of moisture. At a
later stage minute white pustules appear, especially in
cracks ; these eventually become pink. During the white
stage very minute oval conidia are produced in immense
numbers, and later on larger, crescent-shaped conidia
appear. Finally, when the cortex is dead," or nearly so,
a third ascigerous form of fruit develops ; the sporangia
being globose, crimson, and grouped in clusters.

The disease often spreads rapidly ; in one instance a
diseased patch more than two feet long, and reaching
almost round the tree, had formed ten days after
inoculation.

PREVENTIVE MEANS. — The most satisfactory method
is to cut out the diseased patch, along with a margin of
apparently sound cortex. Covering the wound with tar
is not recommended.

Carruthers, The Tropical Agriculturalist, Nov. i, 1898,
P- 359-

MUSHROOM DISEASE

(Hypomyces, sp. )

Cultivated mushrooms are frequently attacked by fungous
parasites before they burst through the soil, and on appearing
at the surface are completely covered with a more or less
dense white felt of mould ; in other instances the mould
becomes tinted pale rose-colour; such mushrooms rarely
increase in size, and never develop properly, but deliquesce
and disappear. Sometimes the young mushrooms are
only slightly diseased, and in such cases the young gills
are not straight as is usual in healthy specimens, but more

134 PLANT DISEASES

or less wrinkled and puckered, and covered with a delicate
cobweblike white mycelium. All such are destroyed by
the parasite at a later stage of development.

The parasites, so far as at present observed, belong to
Vertidllium and Mycogone^ and are supposed to be con-
ditions in the life-history of some species of Hypomyces^
but this has not been demonstrated.

PREVENTIVE MEANS. — All diseased mushrooms should
be carefully removed and burned as soon as they appear,
otherwise the spores, which are formed in immense num-
bers, are diffused by wind, etc., over every part of the
cave or cellar, and settle down on the soil when a new
bed is prepared, and thus extend the disease. Spraying
the walls and soil, in fact every internal part of the building,
with 2j per cent, of lysol before the spawn is deposited,
destroys all spores present, and has been found to materi-
ally reduce the disease ; it also destroys various insects,
more especially Sciara ingenua, which often proves very
destructive to the mushroom crop. The spores or germs
of many kinds of mushroom disease are undoubtedly
introduced along with the spawn. This danger can be
avoided by using artificially prepared spawn formed from
pure cultures of mycelium, which are placed in sterilised
material. A further advantage in this method is that any
particular strain of mushroom can be procured. This
method is now commonly adopted in France.

A high temperature, and stuffy, stationary air, favour the
disease.

Costantin and Dufour, Rev. Gen. Bot., vol. iv. pp. 401,
462, 549 ; vol. v. p. 497.

PLUM LEAF BLISTER 135

PLUM LEAF BLISTER

(Poly stigma rubrum, Pers.)

A parasite often proves injurious to plum and almond
trees by destroying the foliage. It also attacks the sloe and
white-thorn. Reddish patches appear on the leaf, most
frequently, but not always, on the lower surface; these

Fig. 25. — Polystigma rnbrum. i, diseased plum
leaves ; 2, section through a stroma, showing the peri-
thecia ; 3, asci containing eight spores, produced in a
perithecium, XSOQ; 4, spermatia, produced in spermo-
gonia,

spots soon develop into thickened, cushion-like stromata,
the surface of which, towards the end of June, becomes
thickly studded with minute darker dots, which correspond
to the mouths or openings of flask-shaped receptacles
imbedded in the stroma, called spermogonia. These
structures contain numerous slender, curved bodies, called

136 PLANT DISEASES

spermatia, which escape through the mouth of the spermo-
gonium as a mucilaginous mass, the component spermatia
becoming liberated by dew or rain.

Spermatia continue to be produced until the autumn.

In the autumn perithecia are also developed in the
stroma, their complete condition being attained during the
winter after the leaves have fallen. The spores produced
in the perithecia inoculate the young leaves of the host the
following spring.

PREVENTIVE MEANS. — The injury occasioned by this
parasite is in exact proportion to the amount of leaf surface
it occupies, the mycelium not extending beyond the margin
of the stroma. These patches, however, are sometimes of
large size, covering the greater portion of the surface of
the leaf, and, as frequently nearly all the leaves on a tree
are attacked, ripening of fruit and maturing of the wood
become impossible. The most effective means of pre-
venting a repetition of the disease is by collecting and
burning the diseased fallen leaves.

Frank, Ber. der Deutsch. Bot. GeselL, vol. i. p. 58 (1883).
De Bary, Fungi^ Mycetozoa, and Bacteria (Engl. ed.),
p. 215.

BLACK KNOT

(Plowrightia morbosa, Sacc.)

Undoubtedly the very worst fungous disease attacking
cultivated plum and cherry trees known in the United
States, to which country it is at present confined. Accord-
ing to Dr. Halsted it also attacks the following wild trees
in that country : — Prunus chicasa, Mich., Prunus mari-

BLACK KNOT

137

tima, Wang., Primus americana, Marsh, Primus virginiana,
L., Prunus serotina, Ehrb., and Prunus pensylvanica, L.
The fungus is readily recognised by the formation of

Fig. 26. — Plowrightia morbo^a. i, portion of a plum
branch showing the first stage of the disease ; 2, plum
branch with 'black knot,' the stroma bearing perithecia;
3, conidiophores bearing conidia, X 300 ; 4, ascus con-
taining eight ascospores, x 300.

black, rough excrescences on the branches; these are
often several inches in length, and sometimes cause the

138 PLANT DISEASES

branch to curve at the part attacked. The first indication
of the disease is the swelling of the branch, followed by a
longitudinal cracking and gaping of the bark, the wounded
surface soon becoming covered with a dark olive velvety
coating.

Examined under the microscope, this velvet pile resolves
itself into myriads of upright, simple, or branched coni-
diophores, bearing conidia. These conidia are dispersed
by rain, wind, etc., and those that are located on the
tender bark of young shoots soon form the starting-point
of new knots. Later in the season the olive mould dis-
appears, and in its place a thick outgrowth of compact
fungus mycelium, called a stroma, is produced, hard,
nodulose, and black externally. During the winter numer-
ous cavities are formed in the stroma, each containing
many asci, enclosing eight spores each. In the spring the
ascospores are liberated, and in turn infect the host.
Other conidial forms of reproduction are known.

PREVENTIVE MEANS. — Dr. Halsted says : 'The remedies
to be proposed are few in number, and easily applied. The
old one of removing all the knots with a knife and burning
them is highly recommended. However, when a tree is
thoroughly infested, it is not easy to cut far enough below
the excrescence to remove all the fungus. The writer has
frequently seen vigorous trees, highly prized by the owner,
so severely pruned as to leave only a few stubs in place of
the branches, and upon the tips of each the next season
would grow knots of considerable size. In all such cases
there seems only one thing to be done, and that is to
remove the whole tree and cast it into the consuming
burn-heap — the sooner the better.'

All cultivated varieties are susceptible to the disease,

BLACK KNOT , 139

if not equally so, and conidia or spores from any species
of tree infested appear capable of inoculating any other
species ; hence the work of extermination of diseased trees
must extend to wild as well as cultivated forms, and,
furthermore, to ensure success, the movement must be
general, experience having shown that it is of comparatively
little use attending thoroughly to your own trees if your
neighbour fails to follow suit. Legislative measures have
been pressed into force in some of the States in the United
States for the purpose of endeavouring to enforce this
object.

Farlow, Bull. Bussy Inst., 1875, 3 pi.
Halsted, N.Jersey Agric. Coll. Expt. Station, Bull. 78,
figs.

Plowrightia ribesia, Sacc. — Occurs on living branches
of red and black currant and gooseberry. Black patches
are formed under the epidermis, through which the small
black clusters of perithecia protrude, resembling rough,
black warts.

HYSTEBIACEAE

PINE LEAF-CAST
{Lophodermium pinastri, Chev.)

A tiny fungus, producing very minute, elliptical, black
spots on the leaves of various species of pine, causing the
leaves to fall prematurely, and consequently, especially in
the case of seedlings and young trees, finally killing the
plant. The following is abridged from Hartig's detailed
account of the disease : —

140

PLANT DISEASES

Its presence is often first indicated on the primary
leaves of seedlings by the appearance of brown blotches,
the remainder of the leaf becoming purple red.

1 A condition of the fungus termed spermogonia, forming

Fig. 27. — Lophodermium pinastri. i, leaves
with the fungus, natural size ; 2, ascigerous form
of the fungus, mag. ; 3, spermogonium of the
fungus, mag. ; 4, ascus containing eight spores,
also two paraphyses, highly mag. ; 5, a single spore,
highly mag.

smaller black spots than the elliptical, ascigerous form,
often appears first on the leaves, which it kills. The pre-
sumed reproductive bodies, called spermatia, formed in the
spermogonia, have not been observed to germinate. The
mature, ascigerous form only opens for the escape of the
spores after long-continued rain, which thoroughly soaks

HYSTERIACEAE 141

the leaf, causing the asci to swell, and consequently rupture
the apothecium.

' Diseased seedlings usually die, and do so with certainty
unless about half the number of leaves escape the parasite.'

PREVENTIVE MEANS. — It is certainly not advisable to
plant diseased year-old seedlings, nor those of two years
old or more, as such rarely recover the effects of trans-
planting.

If the mycelium of the fungus passes into the tissues,
and especially if the pith is browned, the plant is certain
to die almost at once.

Seed-beds should not be exposed to the direction of
the prevailing wind, especially if it blows over a diseased
area, as spores are almost certain to be carried, and some
of these are almost as certain to be deposited on the seed-
lings. Neither should the beds be formed under older
pines, as such may possibly have some diseased leaves, and
the spores would be washed down by rain. Weymouth
pines are not attacked by this disease, and may take the
place of pines destroyed by the disease if conditions are
favourable for their growth.

Goppert, Verhandl. d, schlesischen Forstvereins, 1852, p. 67.
Hartig and Somerville, The Diseases of Trees (Engl. ed.),
p. no, fig.

According to Hartig the silver fir also suffers from leaf-
cast, old trees even losing the majority of their leaves,
due to a fungus called Hysterium neruisequium. The fruit
forms n black line on the midrib on the under surface of
the leaf. Another species of Hysterium, H. macrospomm,
sometimes destroys the leaves of the spruce. A brown
coloration indicates the presence of the mycelium of the

142 PLANT DISEASES

fungus in the tissues of the leaf. At a later stage the fruit
appears, mostly on the under side of the leaf, as long,
shining, black streaks.

Hartig and Somerville, The Diseases of Trees (Engl. ed.),
p. 1 08, figs.

DISOOMYCETACEAE

SYCAMORE LEAF BLOTCH
(Rhytisma acerinum^ Fries.)

The large black patches so common on the upper surface
of living leaves of the sycamore (Acer pseudoplatanus\
maple (Acer campestre\ A.platanoides, and A. rubrum, are of
fungous origin, and when present in considerable numbers
on almost every leaf on the tree, do considerable injury
by preventing the leaves from performing their proper
functions. The patches are yellow when they first appear
in June or July, soon changing to pitch-black, having the
surface wrinkled or corrugated. The patches become
thickened and scab-like, due to the formation of a thin
stroma, on the surface of which a crop of minute bodies called
spermatia are produced in the autumn. These spermatia
resemble very minute conidia in appearance, but have not
been seen to germinate, and their function is unknown. In
damp weather they ooze out from below the surface of the
cuticle, and cover the surface of the black patches. During
the winter, after the leaves have fallen, an ascigerous form
of fruit is produced, the spores becoming mature in the
spring.

PREVENTIVE MEANS. — It has been experimentally proved
that the spores produced in asci will give origin to the
black blotches, when placed on young, living leaves, and

DISCOMYCETACEAE 143

no other form of reproduction is known ; hence, if diseased
leaves are collected and burned before the ascospores are
liberated in the spring, the disease will be arrested.

Fig. z%.— Rhytisma acerinum. i, sycamore leaf with
Rhytisma blotches ; 2, section through a portion of a
black patch bearing spermatia, x 200 ; 3, ascus contain-
ing spores, also two curved paraphyses, x 300 ; 4, a
free spore, x 300.

The following species of Rhytisma also occur as parasites,
and if injury is being done, the diseased leaves should be
removed, to prevent inoculation the following spring : —

Rhytisma punctatum^ Fr., forms large black blotches,
surrounded by a yellowish line, on living leaves of Acer
campestre, L., A. pseudoplatanus, L., and A. spicatum, Lam.
In this species the black scab or crust is not continuous
as in It. acerinum, but consists of closely crowded small
pieces.

144

PLANT DISEASES

Rhytisma salicinum, F., forms large pitchy-black patches
on leaves of goat willow (Salix capreae, L.) and several
other species of willow (Salix).

CLOVER LEAF SPOT
(Pseudopcziza trifolii, Fckl.)

A fungus that not unfrequently proves destructive to
crops of lucerne (Medicago sativa) and clover (Trifolium).
The leaves are attacked, and first show minute blackish

Fig. 29. — Pseudopeziza trifolii, i, a clover leaf badly diseased,
nat. size; 2, a pustule or fruit of the fungus bursting through
the epidermis of the leaf, which is torn into triangular teeth,
slightly mag. ; 3, an ascus containing eight spores, also two
paraphyses, X4oo.

specks on the upper surface; these increase in size and
extend through the substance of the leaf, showing on the

CLOVER LEAF SPOT 145

under surface also. At a later stage a small brown pustule
appears in the centre of each spot, and most frequently
on the upper surface of the leaf, looking much like the
brown pustule of teleutospores belonging to some Pucdnia \
but when examined under the microscope, the pustule is
seen to consist of numerous asci, each containing eight
colourless, elliptical spores. These ascospores escape
when mature, and are scattered by wind, inoculating those
leaves on which they happen to alight.

The disease when present usually assumes the character
of an epidemic, due to the rapid and abundant diffusion of
spores, and consequently considerably reduces the forage
by preventing growth owing to the destruction of the
leaves.

PREVENTIVE MEANS. — The disease readily survives the
winter on stray plants in the field or on wild clovers, and
unless precautions are taken is likely to infect the crop
the following season. Burning over the field in late
autumn or early spring, if there is not sufficient dry
material present, straw or other refuse might be spread
over the field and burned.

Frequent cutting of the crop prevents the disease from
doing serious damage.

Combs, Iowa State Coll. of Agrie., No. 9, figs. (1898).

LARCH CANKER

(Dasyscypha calydna^ Fuckel.
= Peziza willkommU, Hartig.)

This beautiful little fungus is very destructive to the
larch (L. europea), especially when crowded and growing

K

146

PLANT DISEASES

in a low, damp situation. The ascopbore is i to 2 lines
across, saucer-shaped, without a stem, but attached by a
narrow point, externally white and downy, inside or
hymenium orange-red. Usually occurring in considerable
numbers on the diseased spots.

The fungus is a wound-parasite, its spores entering the
tissue through wounds caused by insects, hailstones, and

Fig, 30. — Dasyscypha calycina. i, portion of a larch
branch diseased ; 2, two fungi, slightly mag. ; 3, an
ascus containing eight ascospores, also two para-
physes,

more especially by branches being more or less split from
the trunk by snow. The first indication of disease is the
yellowing and wilting of the needles. If the base of a
branch bearing such leaves is examined, a mass of resin
will be found oozing to the surface through irregular fissures
in the bark. By degrees the bark is entirely destroyed

LARCH CANKER 147

above the area occupied by the mycelium of the fungus ;
and, if conditions are favourable, the ascophores of the
fungus appear on those sunk and diseased areas. During
the summer the mycelium does not extend to any great
extent owing to the formation of cork between the healthy
and diseased portions of bark; but in the autumn the
mycelium succeeds in entering the living bast, and
consequently the canker-spot continues to enlarge year
by year.

In those cases where the growth of the parasite is rapid,
compared to the growth of the tree, the canker soon
completely girdles the trunk or branches, the part beyond
the region of disease dying. On the other hand, where the
disease is confined to one side of the trunk or branch, the
struggle between host and parasite may continue undecided
for a long time. Hartig states that in the Tyrol he has
seen larches still alive bearing canker wounds of a hundred
years' standing.

In very damp localities larches soon die when attacked,
and without any large canker wounds making their
appearance. Under such circumstances the mycelium
appears to spread quickly through the entire plant, as
proved by the development of myriads of ascophores over
every part of the tree, and not, as is usually the case in
dry districts, confined to the canker-spots.

PREVENTIVE MEANS. — The larch is truly an inhabitant
of Alpine regions ; and although larch canker exists on
trees growing in the higher Alps, nevertheless it never
extends its ravages to the same extent as when the tree is
planted in damp, stuffy lowland localities, hence such
should not be selected.

The disease can be held in check by keeping a sharp

•f THE

I I fc.1 I 1 1 rr M,

148 PLANT DISEASES

look-out for the disease, and removing the canker-spots on
their first appearance, immediately dressing the wounded
portions with a wash of corrosive sublimate in methylated
spirit, or with a strong solution of sulphate of iron, and
afterwards painting over with tar. The fungicide and tar
should be applied immediately the wound is made; to
delay for a day or two is courting further disease.

Wilkomm, Mikroskopische Feinde des Waldes^Q\.\\. p. 167.
Hartig, Unters. ans dem Forstb. List.) vol. i. p. 63.
Hartig and Somerville, Diseases of Trees, p. 117, figs.

VINE SOLEROTINIA

(Sclerotinia fuckeliana, De Bary.)

This fungous pest of the vine has two very different-
looking forms of fruit. One form appears as a dense,
velvety, olive-brown mould, exceedingly common on fading
and dead leaves and herbaceous stems of plants, and which
under certain conditions becomes a dangerous parasite.
This is the conidial form of reproduction, and was at one
time considered as an independent fungus, known as
Botrytis rinerea. The second or ascigerous condition
resembles a shallow wine-glass in miniature, not usually
more than one-tenth of an inch across, supported on a long,
slender stem, springing from a small black sclerotium, and
brown in colour.

The conidial form is most injurious, and, unlike most
parasites, attacks numerous plants belonging to widely
separated families. It is especially destructive to vines,
destroying the leaves, young shoots, and also the in-
florescence and fruit.

Fig. 31. — Sclerotiniafuckeliana,. i, vine leaf with the Botrytts
form of the fungus gro\ving on its surface ; 2, a conidiophore of
the Botrytis with clusters of conidia, slightly mag. ; 3, a
head of conidia, x 300 ; 4, small black sclerotia bearing the
Botrytis form of fruit; 5, a sclerotium bearing two ascophores,
nat. size ; 6, the same, more highly mag. ; 7, a shrivelled grape
with numerous sclerotia imbedded in its skin ; 8, ascus containing
eight spores, also a paraphysis, x 300.

i$o PLANT DISEASES

As already stated, the conidial form appears as a greyish
or brownish olive mould, often forming large patches
which, when examined under the microscope, are found to
consist of stout, erect, smoky-olive stems or conidiophores,
more or less branched upwards, the tip of each branchlet
bearing a cluster of broadly elliptical, colourless conidia.
The mycelium of the conidial form present in the tissues
of the host eventually forms numerous small black conidia.

These sclerotia, after a period of rest, produce either the
conidial form of fruit, or the higher, ascigerous form.

On the other hand, the spores of the ascigerous stage, on
germination form a mycelium, from which either the
Botrytis or the ascigerous form may eventually develop,
depending on conditions at present unknown.

PREVENTIVE MEANS. — Spraying with dilute Bordeaux
mixture, or with potassium sulphide, destroys the conidia,
and thus checks the spread of the disease. Leaves and
fruit attacked by the fungus should be collected and
burned ; otherwise, if allowed to remain lying about, the
sclerotia present in their tissues will eventually produce
spores, which will again infect the young foliage.

De Bary, Morp. and Phys. Fungi (Engl. ed.), p. 224.
Pirotto, Nuovo Giorn. Bot. ItaL, vol. xiii. p. 130 (iSSi).
Viala, Les Maladies de la Vigne, p. 352, figs.

SCLEROTIUM DISEASE

(Sclerotinia sclerotiorum, Massee.
= Sclerotinia liber liana, Fuckel.)

Probably no other parasitic fungus attacks and kills so
many plants of different species, and belonging to widely

SCLEROTIUM DISEASE

separated Orders. Among others may be enumerated
potato, chrysanthemum, hemp, haricot beans, petunias,
zinnias, cucumbers, swedes, turnips, etc. The stem is the
part most frequently attacked, but, according to Potter,
stored swedes and turnips are also destroyed, the disease
first showing itself just above the ground-line as a delicate
white mould encircling the stem. The mycelium also

Fig. 32. — Sclerolinia sclerotiorum. i, portion of a
chrysanthemum stem containing the black sclerotia of the
fungus, nat. size; 2, a sclerotium bearing five asco-
spores, nat. size ; 3, an ascus with spores, and a
paraphysis, x 300.

penetrates into the interior, and gradually extends upwards.
Finally the stem becomes dry and brittle, and falls down.
If such diseased and fallen stems are cut open, a considerable
number of black sclerotia of very variable size and shape
are met with in the pith, surrounded by mycelium.

When the stems decay, the sclerotia are set free and lie

152 PLANT DISEASES

on the ground until the following spring, when they give
origin to usually several more or less funnel-shaped, brown
ascophores supported on long, slender, crooked, dark-
coloured stems.

The spores are ejected from the asci at maturity, and
germinate at once, soon forming a vigorous mycelium
amongst dead organic matter, which afterwards becomes
parasitic, attacking the stems of annual plants near the
ground-line, and acting as already described. It was
shown by De Bary that the earliest mycelium formed after
germination cannot penetrate living tissues as a parasite,
but must first live for some time as a saprophyte.

In addition to attacking the stems of living plants, this
fungus often proves very destructive to tubers and roots
stored for the winter, as dahlias, artichokes, beetroot, and
more especially carrots, surrounding the tubers with a
white cottony mycelium which rapidly causes rotting and
decay, the mycelium of the fungus becoming studded with
black sclerotia, varying from i line to half an inch or more
in length. The rapidity of the disease is much intensified
if there is any tendency to * sweating ' in the stored roots.

De Bary states that this species does not possess a
Botrytis stage; other later observers, however, incline to
the idea that this condition is sometimes produced.

PREVENTIVE MEANS. — A difficult fungus to combat.
Diseased stems containing sclerotia should be collected
and burned, as should also diseased tubers and roots.

Where the disease has previously existed, and there is a
probability of the presence of sclerotia in the soil, it would
be well to sprinkle the surface with soot or quicklime,
which would destroy the mycelium during its period of
saprophytic existence, previous to attacking the young

COWBERRY SCLEROTINIA 153

stems. Fresh stable manure on the surface of the soil
greatly favours the spread of the disease.

De Bary, Bot. Ztg., p. 458, 1886.

Potter, Journ. Board Agric^ vol. iii. No. 2, figs.

COWBERRY SCLEROTINIA

(Sderotinia urnula^ Rehm.
= Sclerotinia vacdnii, Wor.)

During the early part of summer the leaves and young
stems of the cowberry ( Vacdnium vitis-idaea) often show
dark-brown patches or stains, which soon become covered
with a snow-white delicate mildew, which often assumes a
yellowish tinge when old. This mildew, the conidial or
summer form of fruit of Sderotinia urnula, when examined
under the microscope, is seen to consist of simple or
branched chains of conidia, arranged like a string of beads.
As the conidia become mature, the narrow neck connecting
adjoining conidia undergoes a peculiar change in form and
structure, which results in the conidia assuming a lemon-
shaped form, and becoming free from each other. The
mature conidia have a strong smell, resembling almonds,
that proves very attractive to insects, who, along with wind,
convey the conidia on to the stigmas of the Vacdnium
flowers. These conidia germinate, the germ-tubes passing
down the style into the ovary, where the hyphae forms a
sclerotium in the interior of the fruit. Such diseased
fruits fall prematurely, lie on the ground throughout the
winter, and in the spring one or more dark brown, wineglass-
shaped ascophores grow from the sclerotium contained
within the mummified Vacdnium fruits.

154

PLANT DISEASES

The ascospores produced in the spring germinate and
penetrate the young shoots and leaves of the cowberry,
producing the brown spots previously alluded to, from the

y

f

Fig. 33. — Sclei'otinia urnula. i, conidial condi-
tion in young stage, x 250 ; 2, conidial form of fruit ;
at maturity, the narrow portions, or disjunctors,
deliquesce, and set the conidia at liberty, X25o ;
3, ascospores springing from mummified fruits
filled with sclerotia, X3 ; 4, ascus containing eight
spores, x 250 ; 5, paraphyses, x 250 (after Woronin).

surface of which the summer or conidial form of fruit is
produced in less than three weeks.

The following species of Sderotinia also form sclerotia
in the fruit of different species of Vacrinium : —

Sderotinia oxycocd, Wor., on Vaccinium oxycoccos.

Sderotinia baccarum, Schroter, on Vaccinium myrtillus.

CLOVER SCLEROTINIA 155

Sclerotinla megalospora, Wor., on Vaccinium uliginosum.

Woronin, Mem. Acad. Imp. St. Petersburg, ser. vn., vol.
xxxvi., 1888, 10 pi.

CLOVER SCLEROTINIA

(Scleroiinia trifoliorum^ Eriksson.)

During certain seasons this fungus is very destructive to
the different kinds of cultivated clover (Trifoliunt). It
also attacks Sainfoin (Onobrychis sativa), Lucerne (Medi-
wgo sativa), Fenu-grec (Trigonella foenum-graecuni), and
Medicago luptdina.

The leaves are first attacked, and if the weather is suf-
ficiently moist a delicate white mycelium appears on the
surface, and extends to adjacent plants ; finally the leaves
shrivel and decay. Numerous minute, blackish sclerotia
are formed during winter on the dead leaves and roots
remaining in the ground. During the summer these
sclerotia produce one or two ascophores of the usual
Sderotinia type, brown in colour, quite smooth, stem long
and slender, hymenium or disc concave or saucer-shaped,
thus differing from S. sderotiorum. The spores of the
ascophore form directly inoculate the leaves. Conidial
condition unknown.

PREVENTIVE MEANS.— This disease has only been
recorded as present in Britain quite recently, and may
fortunately still be considered as rare. Where clover fields
are attacked, it is necessary to abstain from cultivating this
crop for several years. I have noticed this disease in a
plot of Trifolium incarnatum once near Sheire, Surrey.
Wherever the disease appears it should be promptly dealt

156 PLANT DISEASES

with, otherwise the green fodder supply for our towns may
suffer to the same extent as the sainfoin crop in some parts
of France.

Eriksson, Kongl. Landthbr.-Akad. HandL o. Tidskr.^
1880, No. i.
Prill ieux, Malad. des Plantes Agric., vol. ii. p. 413, figs.

ONION SCLEROTINIA
(Sclcrotinia bulborum^ Wakker.)

Onions, hyacinths, and probably also other bulbs, are
often destroyed in immense numbers by this fungus.
Yellowish blotches appear on the foliage in spring or early
summer. These blotches are soon covered with a velvety
olive-brown mould. The mycelium passes down the
tissues into the bulb, where blackish sclerotia, varying in
size from a rape-seed to a small pea, are formed, more
especially in the outermost scales of the bulb, in some
instances in such quantities that the surface of the bulb is
almost completely covered. During the following spring
small, brown, cup-shaped ascophores, supported on a
slender, wavy stem, spring from the sclerotia.

PREVENTIVE MEANS. — Spraying with potassium sulphide
solution or with dilute Bordeaux mixture on the first
symptoms of the disease will check its spread by diffusion
of the Botrytis spores. Diseased bulbs should be collected
and burned. It is advisable not to plant bulbs where the
disease has existed for at least three years, as the sclerotia
have been shown to be capable of germination when two
years old.

ANEMONE SCLEROTINIA 157

Wakker, Allgem. Vereen. voor Bloembollen-cultiir, 1883-84.
Massee, Gard. Chron., vol xvi., 1894, p. 160; fig. of
Botrytis and ascophore.

ANEMONE SCLEROTINIA
(Sclerotinia tuberosa, Fckl.)

This fungus is very destructive to the wood anemone
(Anemone nemorosa), also cultivated species of Anemones.
The blackish sclerotium varies in form and size, half to
three-quarters of an inch long, and attacks the rhizomes of
the anemone. In the spring numerous long-stemmed,
smooth, dark-brown ascophores are produced. The fertile
portion is at first pear-shaped and closed, then funnel-
shaped, and at maturity expanding until almost flat.

PREVENTIVE MEANS. — Collecting the ascophores in the
spring checks the spread of the disease.

DROOPING DISEASE OF PAEONIES

(Sclerotinia paeoniae, Massee.
= Botrytis paeoniae, O u d . )

Unsightly gaps often appear in beds of paeonies, caused
by this fungus. Healthy-looking plants some time before
the period of blooming suddenly become limp, the stem
droops, and within a few days the plant dies. If the stem
of a diseased plant is examined, a very delicate white mould
will be seen on its somewhat blackened and shrivelled
surface, just above the ground; and at a later stage,
numerous minute black sclerotia are formed in the tissues,
both above and below ground.

158 PLANT DISEASES

The white mould is a Botrytis, producing myriads of
conidia, which, carried by wind, inoculate other plants in
the vicinity. The sclerotia remain in the soil until the
following season, when they produce conidia which inocu-
late the stem near the ground.

PREVENTIVE MEANS. — Drooping stems should be re-
moved at once to prevent the continued formation of
conidia and sclerotia. Gardeners have observed that the
application of green manure as a top dressing causes
paeonies and other plants to become diseased, and this is
undoubtedly true. The manure, even if it does not contain
spores, affords a congenial matrix for spores and sclerotia
present in the ground, in which they reproduce themselves
rapidly, and in the spring, when the young stems push
through the manure, inoculation is almost certain to take
place.

Where the disease has previously existed, the surface
soil should be removed, and replaced with soil mixed with
lime.

Massee, Gard. Chron., Aug. 13, 1898, fig. 32.

TULIP MOULD

(Sclerotinia parasitica, Massee.
—Botrytis parasitica, Cavara.)

Cultivated tulips are often killed by a mould which
forms olive-brown, minutely velvety patches on the stem,
leaves, and flowers. At a later stage smooth lentil-shaped
sclerotia, at first grey, then black, appear, mostly in the
outer parts of the bulb, sometimes being so numerous as
to form black crusts.

SNOWDROP MILDEW 159

PREVENTIVE MEANS.— When the mould is observed,
the plant should be taken up and burned to prevent the
formation of the sclerotia, some of which are often formed
in the soil close to the bulb, and thus endanger subsequent
crops.

Cavara, App. Pat. Veg., 10, tab. vi. figs. 1-4.

SNOWDROP MILDEW

(Sclerotinia galanthina^ Ludwig.
=Botrytis galanthina, Berk.)

The bulb is first attacked, and as the leaves and flowers
appear above ground they are also seized upon by the
fungus, the result being the plant does not bloom, neither
do the leaves develop properly. A careful examination
at this stage reveals the presence of a delicate whitish
mould covering the leaves and flower spathes, and at a
later stage numerous minute black sclerotia are formed in
the tissues of the decaying leaves and in the outer bulb-
scales. The mould is of the usual Botrytis structure, but
the conidia differ in form and size from those of any other
known species, and the fact of producing sclerotia proves
it to belong to the genus Sderotinia, although the higher
Peziza form of fruit is not yet known. .

PREVENTIVE MEANS. — Experience has shown that
diseased plants do not bloom, consequently all such
should be removed on the first indication of the disease;
by so doing, the formation of conidia and consequent
spread of the disease is checked.

The sclerotia resemble small black grains sunk in the
scales of the bulb ; all diseased bulbs should be destroyed.

160 PLANT DISEASES

Smith, Gard. Chrqn.t March 2nd, 1889, p. 2; 1889,
p. 275, figs.

Ludwig, Lehrbuch der niederen Kryptogamen, p. 335.

Oudemans, Verslag Gew. Verd. der Wis-en Nat. Afdeel.,
1897.

DOUGLAS FIR BLIGHT

(Sclerotinia douglasii, Massee.
—Botrytis douglasii, Tubeuf.)

Seedlings and young trees of the Douglas fir (Pseudo-
tsuga douglasii) Carr.) and Wellingtonia (Sequoia gigantea,
Lindl. and Gord.) sometimes have the lead and upper-
most shoots destroyed by the Botrytis form of Sclerotinia
douglasii. The same fungus appears to attack funiferus
communis. A brownish-grey mould appears on the
branches, which soon become curved and finally die, the
needles in the meantime falling off. The Botrytis con-
tinues to form conidia on the fallen leaves, and minute
black sclerotia are formed on the dead branches. Several
young plants of Sequoia gigantea were killed at Kew by
this fungus.

PREVENTIVE MEANS. — If detected at an early stage,
spraying at intervals with Bordeaux mixture or potassium
sulphide solution would destroy the conidia, and check the
spread of the disease. Badly infected trees should be
removed and burned.

Tubeuf, Beitr. z. Kenntniss d. Baumkr., 1888.

A LILY DISEASE 161

'A LILY DISEASE'

(Sckrotinia, sp. )

Professor Marshall Ward has described the Botrytis
form of a Sclerotinia which forms orange-brown and buff
specks on the stem, pedicels, leaves, and buds of the white
lily (Lilium candidum). The ascigerous condition is not
yet known, and this is mentioned more especially for
the purpose of directing attention to the very elaborate
account of the fungus under consideration, which deals
in a masterly manner with the mode of life of the parasite,
and indicates the method by which the mycelium is
enabled to pass through the living tissues of a host-plant.

Marshall Ward, Annals of Botany, vol. ii. p. 319, pi.
xx.-xxiv. (1889).

Several other species of Sclerotinia attack cultivated and
wild plants. In those cases where injury is experienced,
the only means of prevention is to destroy diseased plants,
and desist from cultivating susceptible plants in soil con-
taining sclerotia.

Peziza vesiculosa, Bull. — Tubeuf gives an account of this
fungus, which is so common as a saprophyte on old manure-
heaps and on richly manured ground. It attacks species
of Bahamina, Hyarinthus, Sidalcea, etc., in gardens.
Plants supposed to have been killed by the fungus were
placed under a bell jar, and were soon covered with
the conidial form of Peziza vesiculosa, as described by
Brefeld.

L

162 PLANT DISEASES

The fungus is one of the largest of the Pezizeae, growing
in clusters; cups bladderlike, with a very small aperture
at first, but expanding when old ; substance fleshy, watery,
brittle, pale brown, one to two inches across.

Ludwig, Zdtschr.fur Pflanzenkr^ 1895, p. 12.

Sil '

?*• •**?***&*? • > ***. __

pig, 34. — Peziza vesiculosa. A group of plants, nat. size.

Bulgaria polymorpha, Wetts. — This species has been
recorded as growing on living oak trunks, and I have also
seen it on living beech.

The fungus is usually densely gregarious, bursting through
the bark as a soft, warty, rust-coloured knob, which
gradually expands until it is half to one inch across, with a
flat, black, highly polished disc or hymenium. Entire
substance springy and soft.

Rhizina inflata, Quelet = Rhizina imdulata. Fries. —
This peculiar fungus, which is not uncommon as a sapro-

A LILY DISEASE 163

phyte, growing on stumps, on the ground, and more
especially peat, has been shown by Hartig to be capable
of living as a true parasite, proving very destructive to
various conifers — Abies pectinata, Tsuga mertensiana, Picca
sitkaensiS) Pinus strobus, and Larix europaea, also Casfanea
vesca.

The ascophore forms a thickish crust one to two inches
across, almost flat or irregularly undulate or warted, of a
dark brown colour, sticky or viscid in rainy weather; the
margin is paler and often irregularly lobed or wavy. There
is no stem, but the crust or sporophore is attached to the
ground by numerous pale rhizoids or strands of mycelium,
which spread in the soil.

If a section through the sporophore is examined under
the microscope, numerous long, cylindrical asci are seen,
each containing eight large, pale brown, spindle-shaped
spores.

The root of the tree is the part attacked ; and if the root
of a tree killed by the fungus is carefully removed, a dense
mass of white mycelium is found surrounding and enclosing
the entire root system. No outflow of resin is present.

PREVENTIVE MEANS. — The only thing that can be sug-
gested is the collection and destruction of the sporophores
of the fungus.

Hartig and Somerville, Diseases of Trees (Engl. ed.),
p. 123, figs.

TREE MOREL
(Cyttaria gunnii, Berk.)

Growing in dense clusters on living branches of the
Tasmanian myrtle-tree (Fagus cunninghamii], in the dense

1 64

PLANT DISEASES

shady forests to the west of Tasmania, in early summer.
Was freely eaten by the aborigines in their wild state. The

1

I

Fig. 35. — Cyttaria gunnii. i, groups of fungi on
living branch of Fagus cunninghamii, somewhat
reduced ; 2, section of fungus ; 3, ascus containing
eight spores, x 300.

fungus grows on rough, swollen knots on the branches,
which sometimes reach a large size, and are due to the
presence of mycelium. The sporocarp is pear-shaped,

TREE MOREL 165

hollow, the thick end furnished with pits lined by the
hymenium; colour whitish; about one inch long.

Cyttaria berteri, Berk. — Top-shaped, orange, up to one
inch across. Edible, growing on living branches of Fagus
obliqua, in Tierra del Fuego, Patagonia, and Chili.

Cyttaria darwinii. Berk. — Subglobose, solid, whitish.
Edible. On living branches of Fagus antarctica and F.
betuloides. Tierra del Fuego, Patagonia, Chili. First col-
lected by Darwin.

Cyttaria hookeri^ Berk. — Obovate or clavate, umbonate,
yellowish cinnamon, half to three-quarters of an inch long.
Edible. On living branches of Fagus obliqua and F.
antarctica. Tierra del Fuego, Patagonia, and Hermite
Island, Cape Horn.

Fischer, Bot. Ztg., 1888, p. 816, t. xii.

HEMI-BASIDIOMYCETES

'JEW'S EARS' FUNGUS
(Himeola auricula-judae. Berk.)

Enumerated by Prillieux and Delacroix (Bull, du Minis-
fere de I'Agric.j xii., No. 5, Sept. 1893) as a wound-parasite,
attacking the mulberry-tree.

The fungus is very thin, and flexible like indiarubber,
more or less shaped like a human ear, flesh-coloured or lurid,
the sterile side minutely velvety. Common in Britain on
living branches of elder (Sambucus nigra), which it kills.

166 PLANT DISEASES

MULBERRY ROOT DISEASE
{Helicobasidium mompa, Tanaka.)

Nobujiro Tanaka has described a disease of the mulberry
tree, which is extensively cultivated in Japan for rearing
silkworms. The fungus first attacks the root of the living
tree, and after about two months, above-ground symptoms
are evident, the growth of shoots is arrested, and the
leaves become gradually smaller, and at length die; the
shoots also die as the disease advances. The lowest roots
are killed first, and the tree pushes out others higher up,
which in turn are destroyed, the tree sometimes keeping
itself alive for three years by the successive formation of
new roots. The diseased roots are covered with an
irregular network of purplish-brown strands of mycelium
0-5-1 mm. thick; some of these radiate into the soil. As
the disease proceeds, the fungus creeps above ground,
forming at first a thin effused mass of mycelium of a dark
purple-brown colour, which more or less covers the base
of the stem and branches ; the surface of this felty mass is
smooth and velvety, and the definite margin paler in
colour. Extraneous matter, as dead leaves, branches, soil,
etc., are often enclosed in the rapidly spreading felt. As
growth proceeds, a portion usually develops at right angles
to the branch, and also extends laterally on one or both
sides. The hymenium is produced on every portion of
the free surface of the felt, and is whitish, with a tinge
of violet. The basidia are curved, 1-3 septate, four-
spored.

Numerous sclerotia are formed in the decaying tissues
of dead roots. No remedial measures are given, but the

RHODODENDRON GALLS 167

fungus probably belongs to the category known as root-
parasites, travelling in the soil by means of mycelial strands
or rhizomorphs.

Tanaka, Journ. Coll. Sci. Imp. Univ. Japan, vol. iv. pt. i,
p. 193, pi. xxiv.-xxvii. (1891).

BASIDIOMYCETES

THELEPHORACEAE

RHODODENDRON GALLS
(Exobasidium rhododendri. Cram.)

The presence of this fungus is indicated by the occur-
rence of gall-like swellings on the leaves of Rhododendron
hirsutum and R. ferrugineum. The galls vary in size from
that of a pea to a marble, are at first of a pale yellowish-
green colour, becoming red on the side exposed to sun-
light. During the summer the entire surface of the galls
becomes covered with a very delicate bloom, due to the
presence of basidia, or spore-bearing organs. The my-
celium of the fungus remains in the tissues of the gall.

PREVENTIVE MEANS. — Collect and burn diseased leaves
before the fruit of the fungus is produced. I have observed
that when infested leaves have been removed sufficiently
early, the disease does not appear the following year on
the same plant ; hence probably there is no permanent
mycelium in the tissues, and the only means of infection
is by spores.

Several other species of Exobasidium form galls on
plants belonging to the following genera : — Rhododendron^

168 PLANT DISEASES

Vacdnium, Andromeda, Ledum, Arctostaphylos, Cassandra^
Saxifraga, Symplocus, Bromus, Arrhenatherum. The treat-
ment is in all instances the same as that given under E.
rhododendrL

Fig. 36. — Exobasidium rhododendri. i, galls
formed by the fungus on leaves of Rhododendron
ferrugineum, about nat. size ; 2, basidia bear-
ing a variable number of spores, x 350.

Exobasidium lauri, Geyl., forms club- or horn-shaped
outgrowths up to one foot long, growing from the leaves of
Laurus nobilis and Z. canariensis in Italy and the Canaries.

'BLISTER BLIGHT' OF TEA PLANT
{Exobasidivm vexans, Massee.)

Dr. Watt, who investigated the pests and blights of the
tea plant in Assam under instructions from the Govern-

BLISTER BLIGHT OF TEA PLANT 169

ment of India, says of the present parasite: 'One of the
very worst blights on tea is known to the planters as
Blister blight. I have seen hundreds of acres completely
ruined by it.'

The fungus attacks the leaves, first appearing as a
minute pink spot, which continues to increase in size ; the
upper surface of the leaf at this point becomes depressed,
forming a circular pit, a corresponding bulging out appear-
ing on the under surface of the leaf at the same point.
Several of these warts or blisters frequently form on a leaf.
The convex surface of the blister eventually presents a
minutely velvety or woolly appearance, due to the forma-
tion of the fruit of the fungus on the surface of the blister.
The first fruit consists of small, one-septate conidia, which
often commence germination in situ. These are followed
by basidia, usually bearing two spores each. Some-
times fruit is also produced on the concave side of the
blister.

When the disease has gained a foothold on the leaves,
it also frequently attacks young shoots.

PREVENTIVE MEANS. — Dr. Watt states that the disease
'invariably appears on tea that has not been pruned in the
autumn. About April it extends to the pruned tea, which
has by then come into leaf.' As to whether it would not
be wise under the circumstances to prune all plants, lack
of practical knowledge prevents me saying ; however, the
statement suggests that the mycelium is perennial in the
branches, and produces the first crop of spores the follow-
ing season, which are carried by wind to the pruned
trees. In addition to collecting and burning diseased
leaves, it is absolutely necessary to cut off all diseased
branches.

i?o PLANT DISEASES

Ascertain that the fungus is not also present on wild
plants in the neighbourhood of the tea plantations.

Watt, The Pests and Blights of the Tea Plant, p. 419.
Massee, Kew Bulletin, 1898, p. 109, figs.

GRAPE FLECK

(Exobasidium vitis, Prill, and Del.
Aureobasidium vitis, Viala and Boy.)

Attention was first called to this disease by Dr. Viala,
who observed it on vines, especially Frankenthal and
Chasselas, in France.

On the fruit a little dingy speck first appears. This
gradually increases in size, and becomes livid, afterwards
depressed, with the skin wrinkled and dry. The diseased
portion eventually becomes sprinkled with minute pale
golden or yellow velvety tufts consisting of the fruiting
portion of the fungus, which originate from the copious
mycelium present in the tissue of the grape. This
mycelium is very slender, branched, white towards the
middle of the fruit, but becoming clear yellow just under
the skin. This fungus illustrates one of the most reduced
or primitive types of the Basidiomycetes at present known.
The velvety tufts on the surface of the fruit consist of
basidia bearing a variable number of spores — 2 to 9 — at
or near the apex.

Prillieux has observed this parasite also on the leaves of
the vine, where it forms little white patches.

Var. album, Montem. — Dr. Montemartini has created

GRAPE FLECK 171

this variety for a whitish form of the fungus found on the
leaves and fruit-stalks of vines growing at Trieste, Austria.

Var. tuberculatum, M' Alpine. — This variety appears
mainly to depend on the presence of a more or less
evident stroma, which, however, may sometimes be absent.
The differences observable in spore or other measurements
are of no value, specific or varietal, when the same are
admittedly so variable as in the present species. The
fungus appears to be widely diffused in Victoria. This
fungus was considered as the type of a new genus —
Aureobasidium — by Viala, who was only acquainted with
the autumn form produced on the fruit of the vine.
Prillieux has shown that it also occurs on the leaves of
the vine under the white form in spring, and correctly
states that it conforms in all important points with the
genus Exobasidium. Further, the amount of variation
presented by the typical form overlaps those peculiarities
considered as characterising the two varieties enumerated
above.

Neither of the authors quoted has suggested remedial
measures.

Viala and Boyer, Une Maladie des Raisins produite par
I Aureobasidium vitis^ i pi.

Prillieux, Mai ad. des Plantes Agricoles, vol. i. p. 298,

fig.

M 'Alpine, Additions to the Fungi on the Vine in Australia,
p. 1 6, figs.

Hypochnus cucumeris, Frank. — This spreads as a delicate
grey film over the stems of cucumbers close to the ground,

172 PLANT DISEASES

causing rot and death of the plant affected. It also occurs
on Lupines and Clover.

Hypochnus solani, Prill, and Del. — Forming greyish-white
patches on the lower parts of living potato stems, but doing
no appreciable damage.

Cortidum comedens. Fries. — This species is stated by
Rostrup to be a wound-parasite on the younger branches
of the oak. The fungus originates below the bark, which
eventually becomes torn and recurved, exposing the
hymenium, which is at first purplish, becoming almost
white; slightly viscid when moist. Not uncommon as a
saprophyte on fallen branches, especially hazel.

PARTRIDGE WOOD
(Stereum frustulosum. Fries. )

This fungus is sometimes a saprophyte, at others a
parasite, attacking various forest trees, but especially oak.
It differs from Stereum hirsutum in having no portion free
from the wood on which it is growing, its entire substance
forming a thickish, much cracked, very hard crust, firmly
attached to the wood. The fungus is perennial, forming
a new hymenium or spore-bearing surface each year, on
the surface of the hymenium of the previous year. Hence
the fungus continues to increase in thickness, and on
section presents a distinctly stratified appearance, a
character by which it is readily distinguished from
various other fungi presenting a similar superficial appear-
ance. The surface of the fungus is cinnamon colour when
in active growth, becoming greyish and minutely primrose

PARTRIDGE WOOD

173

when old. The flesh is brown. Each portion of the
cracked patch is an independent fungus, and these troops
of crowded individuals often form large patches. The

Fig. 37. — Stereum frustulosum. i, a dense group of
individuals growing on a piece of oak wood, rather smaller
than nat. size ; 2, section through portion of a fungus,
showing five zones or layers ; 3, section through the
hymen ium, showing two basidia, each bearing four spores,
also three paraphyses rough on the surface with minute
particles of oxalate of lime, x 300.

basidia are club-shaped and bear four spores at the tip.
The basidia are accompanied by numerous club-shaped
sterile bodies or paraphyses, rough with small particles of
oxalate of lime.

174 PLANT DISEASES

Dr. Hartig, who has studied the action of this fungus
on oak wood, states that the peculiar effect produced on
the wood by the parasite is quite characteristic and distinct
in appearance from that produced by any other fungous
parasite. When the mycelium first attacks the wood, the
latter changes to a clear brown colour, variegated with
numerous white patches, somewhat resembling the plumage
of the breast of a partridge. At a later stage the white
patches become holes in the wood, lined with the white
mycelium of the fungus. The remaining portions of the
wood become darker in colour, and very hard.

At this stage the diseased portions of wood present the
appearance of having been riddled by some boring insect.
Eventually the walls of adjoining cavities are pierced by
the mycelium, and finally the wood is more or less com-
pletely disintegrated.

PREVENTIVE MEANS. — Diseased patches should be re-
moved, the surface being cut away until healthy wood is
reached. The wound should then be protected against
further infection by a coat of tar.

As the fungus is also a saprophyte, dead and fallen timber
should be cleared away.

Hartig, Zersetz. des Holzes, p. 103, pi. xiii.
- Prillieux, Malad. des Plantes Agric., vol. i. p. 307, figs. 121-
127.

STEREUM WOOD-ROT

(Stereum hirsutum, Fries.)

A fungus of very variable form, consistency tough and
leathery, thin, sometimes forming irregularly shaped patches,
lying flat on the bark or wood on which it grows ; most

STEREUM WOOD-ROT

175

frequently, however, the uppermost portion of the thin flap
is free from the wood, and spreads at right angles to the
fixed portion. The upper surface of the free portion is
coarsely velvety, at first dingy yellow, and marked with

3.

Fig. 38. — Stereum hirsutum. i, fungus about half nat.
size ; 2, section through same ; 3, basidia, bearing four spores
each, x 350.

concentric zones, becoming grey or whitish when old. The
margin is often wavy or crisped. The under surface, which
is the hymenium, is smooth, and of a clear ochraceous buff

176 PLANT DISEASES

colour. As a rule the plants are imbricated or growing in
tiers, often almost covering branches, stumps, etc.

The fungus is exceedingly common as a saprophyte,
growing on dead wood ; but Hartig has proved that not
unfrequently it acts as a true and very destructive parasite,
attacking various broad-leaved trees.

Being a wound-parasite, the spores germinate first on
a wounded surface, the mycelium gradually attacking the
sound wood, which it destroys.

The mycelium is perennial, and, having once gained
access to a living tissue, continues to extend until the
whole is destroyed.

The wood attacked becomes pale brown first, afterwards
yellowish white.

The thickening of the cell-walls is first dissolved and
used by the fungus, the intercellular plates alone remaining,
and even these are eventually dissolved.

Professor Marshall Ward has quite recently studied this
parasite, and added considerably to the previous account
given by Hartig; and has furthermore succeeded in pro-
ducing sporophores as pure cultures, commencing with the
spore, and passing through all its phases, the first time this
has been accomplished for a Basidiomycete.

PREVENTIVE MEANS. — Wherever the fungus is found
growing on living trees it should be cut away, the wound
washed with paraffin, or corrosive sublimate in water, and
afterwards painted with tar. As already stated, when the
mycelium has once entered the living wood it is very difficult
to eradicate. I have more than once seen the fruit of the
fungus emerge from such wood, and grow on a wound that
had been treated with paraffin and afterwards tarred.

Decayed wood should not be allowed to accumulate, as

APPLE-TREE HYDNUM 177

it is almost certain to become covered with Stereuin, the
spores of which might alight on the wounded surface of a
living tree.

Hartig, Die Zersetz. des Holzes, p. 129, tab. xviii.
Prillieux, Malad. des Plantes Agric., vol. i. p. 314.
Marshall Ward, Trans. Roy. Soc., vol. clxxxix. p. 123,
pi. 17-21 (1898).

HYDNACEAE

APPLE-TREE HYDNUM
(Hydnum schiedermayeri, Heufler.)

According to Thiimen this fungus is very frequently
destructive to apple-trees, developing under the bark, which
is killed, often extending for several feet as a fleshy,
irregular mass, and bursting through cracks here and there
to form its sporocarps on the surface of the bark.

The fungus is often very large, fleshy, irregularly nodulose,
the nodules or pilei producing long spines on their under
surface; flesh yellow, externally yellow or pileus tinged
flesh-colour. Smell spicy.

PREVENTIVE MEANS. — Badly diseased trees should be
felled and used for firewood. The sporocarps of the fungus
should not be allowed to develop.

Thiimen, Zeitsch. f. Pflanzenkr., vol. i. p. 132.

Hydnum diversidens, Fries. — Very shortly stalked, pileus
variable in form, whitish, upper surface densely covered
with erect, variable, incised teeth ; spines more or less

M

1 78

PLANT DISEASES

clavate on the margin, while on the under surface the
spines are awl-shaped, and bear the hymenium. A
wound-parasite on oak, beech, elm and birch.

Fig. 39- — Hydnum schiedermayeri. Entire fungus ;
about one-quarter nat. size.

During decay the colour of the wood is grey, with a
tinge of yellow, alternating with pale brown stripes. The
ferment secreted by the mycelium causes the inner layers

POLYPORACEAE 179

of the cell-walls to swell into a gelatinous mass without
being changed into cellulose before they are completely
dissolved.

Hartig, Die Zersetztmgscrscheinungen des Holzes, p. 97,
pi. xii.

POLYPORACEAE

( Tramdes pin /, Frie s. )

Very hard, forming an irregular, thick, projecting mass,
often almost triangular in section; pileus dark brown,
concentrically grooved, rough, margin strigose; flesh rusty;
tubes long, stratified, rusty; smell pleasant; two to four
inches across. Hartig, who has given a very elaborate
account of the effect produced by this parasite on the
wood, states that the sporophores sometimes live for fifty
years. The fungus is a wound-parasite, attacking various
coniferous trees, and as a rule does not develop on trees
under fifty years of age, as up to that period wounds are
quickly protected by turpentine, whereas later in life
turpentine in the heart-wood is scanty, and thus the
wounds caused by broken branches are not so quickly
protected against floating spores.

Sporophores are only produced after a luxurious
formation of mycelium is present in the living tissues.
Diseased wood assumes a reddish-brown colour, after-
wards white blotches, and finally holes appear here and
there.

The fungus is very abundant in the pine woods of
North Germany, less so in the spruce woods of South
Germany. It is everywhere rare in Britain.

i8o PLANT DISEASES

PREVENTIVE MEANS. — When a tree once produces
sporophores of the fungus, cure is hopeless, and it is not
even worth while taking the trouble to remove the sporo-
phores, as another crop would soon be produced by the
vigorous mycelium present in the tissues. The best thing
to do is to fell diseased trees, and thus save the bulk of
the timber, for if allowed to stand, the great bulk of the
wood is rendered useless ; besides which, the sporophores
liberate spores that in turn inoculate other trees.

Hartig, Wichtige Krankh. der Waldbaume, p. 43 ; Zer-
setzungs. des Holzes, p. 32, pi. v. and viii.

Hartig and Somerville, Diseases of Trees (Engl. ed.),
p. 191, figs.

Tubeuf and Smith, Diseases of Plants (Engl. ed.), p. 453,
figs.

Trametes suaveoleus, Fr., occurs as a parasite on willows.
Bracket-shaped, pileus whitish, downy ; flesh white, rather
soft and corky; pores white, then brownish. Smell,
especially when vigorously growing, fragrant, resembling
aniseed.

PORIA WOOD ROT

(Poria vapor aria, Fries.)

One of the commonest and most widely distributed of
British fungi, and as a saprophyte occurring on almost
every fallen branch to be found lying on the ground.
Every part of the fungus is inseparably attached to the
matrix, forming a thin crust, white at first, becoming dingy
with age. The entire surface except the extreme margin

PORIA WOOD-ROT

181

is covered with irregularly shaped, minute pores, which
are often slightly curved or inclined to become elongated.
The walls or dissepiments separating the pores are very
minutely toothed when seen under a pocket lens.

t

"

, ff

l

Fig. 40. — Poria vaporaria. i, portion of a fungus, nat.
size ; 2, section of same.

Hartig states that this fungus is very common on spruces
and pines as a parasite, attacking roots or parts above
ground as a wound-parasite. The mycelium often forms
white, branched, floccose strands, somewhat like those of

i82 PLANT DISEASES

the ' dry rot ' fungus (Merulius lacrymans) in chinks, or
between the dead wood and bark.

This fungus also proves very destructive to worked
timber, forming snow-white expansions and long strands
of mycelium on the surface of beams, etc.

Hartig suspects that the white strands of mycelium may
travel underground from a diseased centre, and attack
adjoining trees, but is not certain on this point.

PREVENTIVE MEANS. — When worked timber is attacked,
the only hope of success turns on being able to dry the
timber as quickly as possible by admitting air, otherwise
the fungus spreads rapidly, and quickly destroys the wood
after the manner of { dry rot,' for which it is sometimes
mistaken in the barren condition.

Hartig, Die Zersetzungserscheinungen des Holzes, p. 45,
tab. viii.

Hartig and Somerville, Diseases of Trees, pp. 198 and
213.

ROOT-ROT OF CONIFERS

(Fames annosus^ Fries.
•=.Trametes radiciperda, Hartig.)

Probably the most destructive of fungi attacking
coniferous trees, occurring on species belonging to Pinus,
Picea, and Abies ; has also been noted as attacking
Juniperus communis. Hartig has also seen it on the roots
of old stumps of Betula and Fagus, but doubts its occur-
rence as a parasite on Dicotyledons.

The fungus is a true parasite, germinating spores gaining
an entrance to the living tissues of the root, and forming a

ROOT-ROT OF CONIFERS

183

very thin, white felt of mycelium between the bark and the
wood, hyphae from which attack the wood. The contents
of the living cells change to a brown colour, and finally

Fig. 41. — Fomes annos^^s. i, portion of fungus, half
nat. size; 2, section of same, showing the stratified
tubes in three layers, nat. size ; 3, portion of hymenium
showing the tubes and their openings or pores, slightly
mag.

almost disappear ; the wood next assumes a pale, yellowish-
brown colour with scattered white patches, each having
a black spot in the centre. Finally the cell-walls are

184 PLANT DISEASES

converted into cellulose and used by the fungus as food.
Hartig states that in the Scots fir the disease does not pass
from the root up into the trunk ; this is considered to be
due to the abundance of resin, more especially in the lower
part of the stem, which prevents the upward extension of
the mycelium, whereas in the spruce and Weymouth pine,
which contain but little resin, the rot extends high up the
trunk. During the progress of the disease flat sporophores
are formed on the underground roots ; whereas, after the
tree is dead, more highly developed sporophores develop
on and around the base of the stump.

The sporophore is extremely variable in size and form ;
sometimes, as already stated, resembling a thin white cake,
half to one inch across, with the white hymenium upper-
most.

In the above-ground condition the fungus resembles a
white crust attached to, and following the irregularities of,
the wood, producing here and there a free, projecting
portion, or several of these overlapping. The upper surface
is brown, and very irregularly tuberculose and wrinkled,
the white hymenium being situated on the under surface
of such free, projecting portions. The pores are minute
and rounded. The whole fungus is woody and hard, and
sometimes reaches to six inches across.

PREVENTIVE MEANS. — Diseased trees should be removed
at once, and the site isolated by a narrow trench, taking
care to include within the trench all roots of the diseased
tree, as Hartig has demonstrated that where the root of a
healthy tree is in contact with a diseased root, the fungus
can pass from one to the other.

The sporophores should be collected and burned when-
ever they appear, as their frequent occurrence on roots

GOOSEBERRY POLYPORUS 185

present in the burrows of mice or other animals suggested
the idea to Hartig that the spores might be carried by the
fur of animals — mice, etc. — from one locality to another,
and thus spread the disease. Brefeld has shown that a
conidial form of reproduction is also possessed by this
fungus, which may be a further means of diffusing the
fungus.

Hartig, Zersetzungserscheinungen des ffolzes, p. 14, pi. i.-iv.
Marshall Ward, Timber and some of its Diseases, p. 142.
Brefeld, Unters. aus dem Gessamtgeb. der Mykol.^ vol. viii.
(called Heterobasidion annosum}.

GOOSEBERRY POLYPORUS

(Fomes ribis, Fries.)

A parasite not uncommon on the stems of old gooseberry
and currant bushes, growing in an imbricated manner;
that is, several specimens growing above each other on
the stem of the host.

The pileus is woody, thin, and horizontal, upper surface
yellowish-brown, minutely velvety when young, becoming
almost bald with age, usually with concentric zones. Pores
very short, hymenium brownish-grey; flesh thin, rather
soft, rusty brown.

PREVENTIVE MEANS. — The fungus is perennial, and only,
as a rule, grows on old plants, which from every point of
view should be replaced by young trees.

TINDER FUNGUS

( Fomes fomentarius , Fries.)

This fungus is a very destructive wound-parasite, attack-
ing the beech (Fagus sylvaticd) more especially, although

1 86

PLANT DISEASES

it also occurs on the elm (Ulmus campestris\ and on various
fruit trees, etc. The sporophore resembles a horse's hoof
or an inverted bracket, and varies from three to seven
inches across, or sometimes even more. The upper, convex,

/itt*i& r r, i

- . ii

Fig. 42. — Fomes fowentarius. Entire fungus with a
portion cut out to show the stratified pores, about one-
quarter nat. size.

sterile surface is dingy brown, and marked with concentric
ridges ; when in full vigour the entire upper surface is
covered with a brown powder resembling snuff, a character
by which this fungus can be distinguished from allied
species. The edge is white at first, but finally becomes
dark-coloured like the rest. The hymenium, situated on

TINDER FUNGUS 187

the under surface, is almost flat, powdered with white meal
when young, afterwards rusty brown, and covered with very
minute holes, the openings of tubes which bear the spores
on their walls. The spores are oval and brown. A slice
or section through the entire fungus is more or less tri-
angular, the upper portion or flesh is rust-colour and
rather soft ; the tubes are arranged in layers, or stratose,
and coloured like the flesh.

This fungus resembles in general appearance the ' False
Tinder Fungus ' (fames igniarius\ from which it is distin-
guished by the softer flesh, and more especially by the
brown spores. In the last-named fungus the spores are
colourless.

After gaining access to the living tissues of the tree
through some wound, the heart-wood is first attacked, which
assumes a white colour and becomes broken up into square
pieces by the action of the mycelium, which forms thin,
tough white sheets, spreading from the wood towards the
bark.

According to Tubeuf, the more or less evident groove or
channel, so often present on the trunk above and below a
sporophore of the fungus, is caused by the mycelium having
killed the cambium, and thus prevented the growth of
wood at these parts.

At one time the flesh of this fungus was used for tinder,
and at the present day, after being beaten and converted
into pliant, felt-like sheets, is made into a variety of articles,
fancy and useful, as bedroom slippers, chest-preservers,
purses, smoking-caps, bags, etc. A series of articles manu-
factured from this material are exhibited in No. 2 Museum,
Kew Gardens.

PREVENTIVE MEANS. — When the fungus appears on a

i88 PLANT DISEASES

living tree it should be cut out, and the wound dressed
with tar. As a rule the fungus attacks the lower part of
the trunk, gaining an entrance very frequently at those
irregularities of the surface which are kept constantly wet
by rain or dew trickling down the trunk. All dead trees and
fallen timber should be removed, as these serve as a nursery
for the present and numerous other species of fungi, which
live as saprophytes until an opportunity for attacking living
trees presents itself.

FALSE TINDER FUNGUS

(fbmes igniarius, Fries.)

A wound-parasite, destructive more especially to oak-
trees, but attacking also apple, willow, alder, and various
other trees, exclusive of conifers. The fungus is perennial,
first appearing as a roundish knob, which eventually de-
velops into a hoof or bracket- shaped structure, four to
eight inches across, which usually remains thinner than in
the typical form of Fomts fomentarius. The upper surface
is minutely velvety when young, finally becoming bald,
reddish-brown, and at length blackish, very hard, and
more or less cracked and broken up into ridges. The
hymenium is cinnamon colour, the tubes minute, and in
old plants are stratose or arranged in layers. The flesh is
very hard, rusty brown, and zoned. Spores colourless and
almost globose.

The present fungus superficially resembles Fomes fomen-
tarius, but is readily distinguished by the colourless globose
spores and very hard flesh, which is useless for making
tinder or fungus-felt.

The wood of the host becomes brown during the first

FALSE TINDER FUNGUS 189

stage of attack, and afterwards white, or with a slight tinge
of yellow, and quite soft. The inner layers of the walls of
the cells are first absorbed by the mycelium, the middle
lamellae being afterwards converted into cellulose and
used as food by the fungus. In this way the whole of the
heart-wood is absorbed.

PREVENTIVE MEANS. — The parasite gains an entrance
into the host through wounds, broken branches, holes
made by woodpeckers, etc. If the sporophores are cut
out on their first appearance, and the wounds protected by
tar, the life of the tree may be considerably prolonged ; but
it must be remembered that the mycelium having gained
access to the living tissues of the host, it continues to
spread, and the most certain method is to reduce the possi-
bility of infection to a minimum by destroying the fungus
wherever and whenever it appears, and also to remove old
and useless trees, which favour its growth.

Hartig, Zenetzungserschdnungen des Holzes, p. 114,
pi. xv. and xvi.

Prillieux, Malad. des Plantes Agric., vol. i. p. 359.

BIRCH POLYPORUS

(Polyporus betulinus, Fries.)

This fungus is unfortunately too common on the trunks
of birch trees, and has such marked features that it cannot
be confounded with any other species. The general shape
is that of a horse's hoof. The upper surface is perfectly
smooth, white, or often brownish, the brown skin often
cracking and peeling off. The margin is thick and in-

190

PLANT DISEASES

curved; flesh very thick, soft, pure white; pores on the
under surface very minute, white. Varying in size from
three to eight inches across.

When the fungus first attacks the living wood it pro-

Fi&- 43- — Polyporus bet^ll^n1ls. Fungus about one-quarter
nat. size ; section of same.

duces a brown discoloration, due to a ferment present in
the mycelium ; by means of this substance the thickening
layers of the cell-walls are dissolved and absorbed, the
middle lamellae of the cells alone remaining. Finally
cracks are formed in the soft, decayed wood, containing

BIRCH POLYPORUS 191

white strands of mycelium. The liber and bark are also
attacked, and the fruit of the fungus first appears under
the form of small white knobs in cracks of the bark, each
knob developing into a pileus or spore-producing structure.
Although the pileus is an annual production, it is probable
that the mycelium is perennial in the wood, gradually
encroaching on sound portions of the trunk, and producing
new pilei every season.

PREVENTIVE MEANS. — Healthy trees are first inoculated
at some broken surface by means of floating spores; hence,
to prevent the diffusion of spores, the fungi must be
systematically destroyed. An old birch-tree having the
trunk ornamented with numerous well-developed pilei of
Polyporus belulinus is certainly an artistic object, and
numerous such can be seen in the woods at Birklands, in
Sherwood Forest ; but where the trees are grown for other
purposes, such diseased examples should be promptly
removed, otherwise they form a centre from which myriads
of spores are being liberated annually, and the spread of
the disease under such favourable circumstances is certain.

Prillieux, Malad. des Plantes Agric., vol. i. p. 367.

HEART- WOOD ROT

(Polyporus hispidus. Fries.)

This fungus attacks the majority of broad-leaved trees ,
in orchards the apple is most frequently attacked. The
parasite is readily recognised by its coarsely velvety, dark
brown pileus or upper surface, thick, dark-coloured, fibrous
flesh, and long, yellowish-brown pores. Large specimens

192

PLANT DISEASES

are almost semicircular in shape, fixed to the trunk by a
broad base, and measure six inches to a foot across.
When actively growing the tubes exude water, which drips
away in considerable quantities, even in very dry weather.

l

,,

Fig. 44. — Polyporus hispidus. i, two plants much reduced ;
2, section through a fungus showing the pileus, a, and the tubes,
b ; 3, two basidia bearing spores, x 300.

Every part of the fungus yields a deep yellow colour when
soaked in spirit or in an alkaline solution.

Being a wound-parasite, the mycelium can only gain

HEART-WOOD ROT 193

access to living tissues through a wound. The heart-wood
is first attacked, the trunk eventually becoming hollow,
but frequently continuing to live for some years, until the
outermost and youngest layers of wood are destroyed.
The disorganised heart-wood is of a yellowish-white colour,
and very soft, and there is a narrow band of a dark brown
colour, which indicates the outward point of progress of
the mycelium, which is most vigorous in the region of this
band of colour, and pushing thence into the younger, still
sound wood.

PREVENTIVE MEANS. — Same as for other species of
Polyporus.

Prillieux, Malad. des Plantes Agtic.^ vol. i. p. 352.

HEART-WOOD EOT

(Polyporus sulphureus, Fries.)

This showy fungus is not uncommon as a parasite on
the trunk of various trees, as oak, alder, willow, poplar,
pear, apple, Robinia, and larch. When quite young it is a
roundish, fleshy knob, which grows into an irregularly
flattened body, the margin being often crisped or wavy,
and bearing the very short, minute pores or hymenium on
its under surface. In vigorous specimens there are several
such overlapping portions or pilei, the whole frequently
weighing several pounds, and measuring six inches to a
foot across, or sometimes even much more. The upper
surface is smooth, and varies in colour from pale yellow to
orange, becoming bleached and pale when old. The
under surface is bright sulphur-yellow. The flesh is white,

N

I94 PLANT DISEASES

rather soft, and easily broken. The entire fungus is brittle,
has a very disagreeable smell, and is poisonous.

In addition to the usual means of reproduction by spores,
two other methods of reproduction are known ; one by
means of sporelike bodies called conidia, which are pro-
duced in great abundance from the mycelium growing in
cavities in the wood destroyed by the fungus, or sometimes
in receptacles in the flesh of the fungus itself. The second
form of reproduction in addition to that of the spores also
consists of conidia produced in the interior of special
receptacles, which resemble the young stage of the ordinary
spore-bearing pileus, from which they differ in not producing
pores bearing basidia. These last-named structures were
at one time considered to be an independent fungus be-
longing to a genus called Ptychogaster, and the form we
now know as forming a link in the life-history of Polyporus
sulphur eus was called Ptychogaster aurantiacus.

The fungus is an annual, grows rapidly, and decays in
the autumn. It is a wound-parasite, gaining access to the
living part of the trunk by means of mycelium which
originates from the germination of a spore or conidium on
the surface of a wound, such as a broken branch, or an
imperfectly protected surface exposed by pruning. The
heart- wood is first attacked, the mycelium gradually extend-
ing towards the sap-wood. During decay the wood
changes to a clear reddish-brown colour, cracks, patches
of white mycelium appearing in the crevices.

PREVENTIVE MEANS. — From what has been described
respecting the mode of attack of the fungus, it will be seen
how important it is to trim the ends of broken branches,
and to protect cut surfaces with some fungicide. If the
fungus has gained a footing on the trunk, it should be

Fig. 45. — Polyporus sulphureus. i, an entire fungus about ore-
quarter nat. size ; 2, section through the same, showing the thick,
fleshy pileus at a, and the tubes, which have the cavity lined with
the hymen ium, or spore-bearing surface, at b\ 3, a basidium bearing
four spores, x 300.

i96 PLANT DISEASES

removed, the surrounding wood cut away to the depth of
an inch round the wound formed, so as to remove the
mycelium and conidia that may be present. The cut
surface of the wood should then be washed with a saturated
solution of corrosive sublimate in spirit, and afterwards
painted over with tar. If the broken end of a branch is
attacked, it should be cut off far enough behind the point
of attack to make certain of removing the portion of wood
containing the mycelium of the fungus, and this should
include six inches if practicable ; for, although the fruiting
portion of the fungus is an annual, its mycelium, when
once in the wood, appears to extend its ravages from year
to year. As a matter of course the fungus should be
destroyed whenever it appears, as its spores and conidia
are carried to a considerable distance by \\ind. By destroy-
ing the fungus is not simply meant removing it from a tree
and crushing it under foot, which only in reality means
spreading its spores ; it should be either burned or buried,
the first remedy being most effectual.

Hartig, Die Zersetzungserscheinungen des Holzes, p. 109,
tab. xiv.

Marshall Ward, Timber and some of its Diseases, p. 165.

Various other species belonging to the Polyporeae have
been proved to be parasites, or are suspected of being
such.

Polyporus schweinitzii , Fr. — A large brown fungus with
a coarsely velvety pileus and soft brown flesh, pores
large, irregular. Superficially resembling P. hispidus, but
distinguished by the short central stem. It attacks the
larch, Scots fir, and Weymouth pine.

HEART-WOOD ROT 197

Poly poms borealis, Fr. — -Bracket-shaped, or sometimes
kidney-shaped and narrowed at the point of attachment,
often imbricated ; pileus whitish, hairy ; flesh rather soft,
whitish ; pores irregular in form, edges toothed. Allied to
P. betulinus. Attacks spruce more especially, causing a
white rot of the wood.

Polyporus squamosus, Fries. — Clustered ; pileus broad,
thin, rather soft, upper surface whitish and scaly; pores
short, becoming irregularly torn ; stem short, black at the
base, not central. Common on many kinds of broad-
leaved trees.

Polyporus dryadetis^ Fr. — Bracket-shaped, thick, attached
by a broad base, six to ten inches across, brown, rugged,
margin paler and exuding drops of water; flesh rusty,
velvety, fibrous. Attacks the oak ; the heart-wood is
striped with white or yellowish bands.

Pomes fulvus, Fr. — Very hard, convex above and below ;
pileus even, downy, tawny, then greyish ; flesh rusty ; pores
minute, two to four inches across. Occurs on plum, poplar,
hornbeam.

Fames hartigii, Allesch. — Hard, irregularly bracket-
shaped ; pileus reddish-brown, smooth ; flesh tawny,
stratose ; tubes not distinctly stratified. Occurs on silver
fir and spruce, causing a white rot of the wood.

Fomes pinicola, Schweinitz. — Bracket-shaped, thick be-
hind; pileus grey, margin thickened, reddish; hymenium
yellowish-white; flesh white. Occurs on living trunks of

198 PLANT DISEASES

various conifers, and also on some broad-leaved trees in
the United States.

Poria laevigata. Fries, forms hard rusty-brown crusts
on the bark of birch trunks. A true parasite, destroying
the last-formed wood of each year, hence the annual rings
of wood become free from each other.

Polyporus giganfeus, Fr., often forms dense masses of
overlapping flaps or pilei, two to four feet across. The
pilei are thin, pliant, brownish, slightly zoned ; pores
minute, very short, becoming dark-coloured at once when
bruised, a character by which this species can be recog-
nised from allies. Often springs in dense masses from the
roots of living trees, and is probably parasitic.

Fistutina hepatica. Fries. — The beefsteak fungus ; re-
sembling overlapping flaps of liver in shape, colour, and
consistency; grows on living oaks

Dedaelea quercina, Fries, is very common as a saprophyte
on oak stumps, and is also said to attack living oaks. It
is a bracket-shaped fungus, six to ten inches across ; the
entire substance is tough and corky ; pileus dingy white,
marked with concentric grooves. The hymenium consists
of thick, flexible plates, branching and anastomosing to
form long, wavy, irregular pits.

DRY EOT

{Merulius lacrymans^ Fr.)

Although not destructive to living trees, 'dry rot' is
so well known that a few observations culled from the

Fig. 46. — Merulius lacrymans. ' Dry rot' growing en a
beam ; nat. size of a young specimen.

200 PLANT DISEASES

luminous account of this fungus given by Hartig will be
of value.

Wood that is perfectly sound when felled may become
diseased even before leaving the forest, especially in the
case of peeled trees lying on the ground. During drying,
the wood cracks, and spores often enter these cracks, which
close up when the wood is thoroughly wetted, enclosing the
spores. These germinate and attack the woody tissues,
and too frequently continue their work until the wood is
used, when, if conditions are favourable, the well-known
' dry rot ' soon makes its presence evident.

If fungus mycelium is present in wood used for structural
purposes, and any portion comes in contact with moisture,
as the ends of joists joining a damp wall, the mycelium
soon commences to grow actively. The use of damp
sound-deadening material is very productive of ' dry rot ' ;
clean dry gravel or coarse dry sand is best; and on no
account use coal-dust, cinders, or any other substance
capable of forming an alkaline solution with moisture, as
the spores only germinate in an alkaline solution.

If 'red-stripe' wood is used for beams, etc., the ends
likely to come in contact with damp walls, etc., it should be
thoroughly treated with creosote. * Red-stripe ' is the early
stage of an attack by the mycelium of ' dry rot,' and it is
far better not to use such in buildings ; but as this is con-
stantly done, the next best thing is to use creosote or
some other material that will prevent the spread of the
disease.

The fungus first appears as a thin white film of mycelium,
and gradually becomes thicker at the centre, where it
assumes an irregularly porous structure, and changes to
a rich rusty-brown colour; the substance is soft, and the

TREE ROOT ROT 201

white mycelium at the margin gradually encroaches on the
surrounding parts, being especially favoured by a damp,
stuffy locality.

Hartig, Der dchte Hausschwamm (Merulius lacrymans\
1885.
Hartig and Somerville, Diseases of Trees, p. 212.

AGARICACEAE

TREE ROOT ROT
(Armillaria mellea, Vahl.)

This very destructive fungus is probably the commonest
and most generally distributed of British 'toadstools.'
In addition to attacking nearly all kinds of orchard trees,
it destroys various species of forest trees, including
conifers.

The fungus commonly grows in dense clusters round
the roots of growing trees ; it also frequently occurs on
dead stumps and trunks. Sometimes it appears to be
growing in the naked ground, but in such instances it
originates from buried wood, roots, etc.

The cap or pileus is two to three inches across when
expanded, of a pale honey-yellow or wax-yellow colour,
and is generally ornamented with minute, darker scales ;
the stem is three to six inches long, smooth, and coloured
like the cap, often deeper honey-colour near the base ; the
gills are white when young, becoming cream-colour, and
during the young stage are hidden by a membrane stretch-
ing from the stem to the edge of the cap; as the cap
expands, this membrane breaks away from its edge, and

203

PLANT DISEASES

forms a frill or ring round the stem ; the spores are white,
and are produced in great profusion, settling on objects
near in the form of a dense white powder.

Fig. 47. — Armillaria mellea. Group of plants about one-quarter
nat. size.

The roots of trees are attacked first, the mycelium of the
fungus gradually passing up into the base of the trunk.
The wood is not penetrated to any great depth ; but as the

TREE ROOT ROT 203

portions attacked are vital parts, the young wood, cambium,
and bark, and as the trunk is attacked simultaneously all
round, the tree soon succumbs to its enemy. The mycelium
of A. mellea is so thoroughly characteristic that it can be
recognised with certainty, even when the fructification is
absent. On examining roots attacked by this fungus, its
mycelium is seen under the form of blackish, cordlike
strands of the thickness of fine twine, which creep over the
surface of the roots and the base of the trunk close to the
ground, and in addition radiate in the ground on every
side, where they continue to grow and increase in length
until they come in contact with the roots of neighbouring
trees, which are attacked, and become in turn centres from
which the mycelium spreads in the ground as before, in
search of new victims.

The black, cordlike strands of mycelium, known as
rhizomorphs, do not penetrate the roots, but give off
irregularly arranged delicate branches at intervals; these
branchlets enter the roots and form thin white sheets of
mycelium running between the bark and the wood, and are
known as subcortical rhizomorphs. Hyphae from these
latter penetrate the wood for a short distance, mostly
following the medullary rays, branches of hyphae passing
into the vessels of the wood, which soon become choked
with a dense mass of mycelium. In conifers the mycelium
fills the resin canals, and destroys the cells forming their
walls, the resin exuding through the bark in large masses
at the base of the trunk.

PREVENTIVE MEANS.— In orchards, etc., where only few
trees are attacked, it is advisable, as suggested by Hartig,
to isolate such trees, by digging a narrow trench about a
foot deep round each, at some distance from the trunk;

204 PLANT DISEASES

thus preventing, to a great extent, the spreading of the
underground rhizomorphs to adjoining trees.

Armillaria mellea is edible ; hence if the fungus appears
it may be eaten, and, although rather devoid of flavour, if
properly cooked forms by no means a despisable dish.
However, apart from this, the fungus should always be
collected and burned when it appears in the neighbourhood
of fruit or ornamental trees, as, if the spores are allowed to
disperse, they germinate and produce the creeping rhizo-
morphs. A fertile source of infection consists in the careless
manner in which the base of the trunk or partly exposed
roots of trees are often wounded by the spade, cart-wheels,
and perhaps more especially by grass-cutting machines;
such wounds forming a starting-point for the attack of
various kinds of injurious parasitic fungi. All such wounds
should be at once protected by painting over the broken
surface with tar, which prevents decay and also the germina-
tion of the spores of fungi on the wound.

Hartig, Die Zersetzung. des ffolzes, p. 59, tab. xi., figs. i.-v.
Hartig, The Diseases of Trees (Engl. ed.), p. 207, with figs.
Prillieux, Malad. des Plantes Agric., vol. i. p. 377.
Marshall Ward, Timber and some of its Diseases, p. 155,
figs.

BEECH AGARIC

(Armillaria mutida, Schrad.)

This fungus is a wound-parasite on the beech. At High
Beech, Epping Forest, where this fungus is abundant on
decaying beeches, a healthy branch of a beech having been
broken off, the wound was inoculated with the spores of

Fig. 48. — Armillaria mellea. 2, section through a plant,
a, pileus ; b, gills ; c, ring ; d, ttack cordlike strands of my-
celium ; 3, portion of hymenium or spore-bearing surface of
the gills ; a, basidium bearing four spores, x 300; 4, portion
of a root with branching strands of the mycelium surround-
ing it ; at a, a cluster of young fungi are springing from the
mycelium ; 5, section through the black rhizomorph or my-
celium, showing the thick-walled cells forming the outer
black rind, and the thin-walled, colourless cells forming the
inner portion, x 400.

206 PLANT DISEASES

A. mucida. At the end of the second season after inocula-
tion, the branch was killed for a considerable distance, and
the sporophores of the fungus appeared in abundance.
The spores also germinate readily on very small wounds
made in the bark. A reddish-brown zone indicates the
point reached by the mycelium of the fungus in the wood.
The decayed wood is quite white, and very tender.

The fungus often grows in clusters, and is readily
recognised by being white, and everywhere exceedingly
glutinous, as if smeared with thick gum. There is a ring
on the stem, which is sometimes greyish, as is also the cap.
The fungus is edible, and has a very pleasant flavour.

PREVENTIVE MEANS. — Destroy the fungus, and protect
wounded parts with tar, filling up cavities used for nesting
by birds.

BANANA DISEASE

(Marasmius semiustus, Berk, and Curt.)

In Trinidad and other islands in the West Indies a
banana disease is not uncommon, due to the presence of
a small agaric having the pileus half to one inch across,
very thin, and yellowish-brown ; gills rather wide apart,
thin, dirty white, stem about half to three-quarters of an
inch long, very thin, with a flattish foot of attachment.

These fungi grow in immense numbers on the stem of
the banana plant, and the mycelium permeates the tissues
and attacks the inflorescence or the flower-stalk as it grows
up the centre of the leaf-sheaths forming the ' stem.' In
old or dead plants immense numbers of minute whitish
sclerotia, usually not larger than the head of a pin, are
present in the tissue of the leaf-sheaths.

SUGAR-CANE AGARIC 207

PREVENTIVE MEANS. — Diseased stems should not be
allowed to lie and rot on the ground, otherwise the
sclerotia present will, in some form or other, reproduce
the pest; burning is the only safe method of dispensing
with such diseased material. The fungus should be
removed from stems as early after its appearance as
possible.

Marasmius sacchari, Wakker. — Infection experiments
have proved this agaric to be a true parasite on living
stems of sugar cane in Java.

Wakker and Went, Zeikten van het Sinker tiet op Java,
p. 194, pi. 5.

SUGAR-CANE AGARIC

(Schizophyllum commune, Fr.)

This fungus is said to be parasitic on stems of cultivated
sugar-cane in the West Indies. It has also been recorded
as a parasite on the mulberry-tree by Prillieux.

The pileus is fan-shaped, without a stalk, very thin and
pliant ; upper surface whitish or grey, very hairy, gills
radiating from the point of attachment, forked, pale
brown, margin split.

Prillieux and Delacroix, Bull, du Ministire de CAgric.,
No. 5, Sept. 1893.

SLIMY TREE AGARIC

(Pholiota adiposa, Fries.)

This is a very showy fungus usually growing in clusters;
when fully expanded the cap is two to four inches across,

208 PLANT DISEASES

and the curved stem three to six inches long ; the colour
of every part is clear yellow. The cap is covered with a
glutinous liquid, and like the stem is ornamented with
rust-coloured scales arranged in irregular circles; these
scales, along with the glutinous substance, are usually
washed off by rain as the fungus becomes old. The gills
are at first pale yellow, then rusty orange.

This fungus is not uncommon as a saprophyte, growing
on decaying timber, stumps, trunks, etc. ; but Tubeuf has
shown that not unfrequently it becomes a wound-parasite,
growing on living trunks of silver fir, beech, plum, etc.
The white wood of the fir becomes yellow or honey-
colour with scattered patches of light brown, and eventu-
ally breaks up into irregular pieces under the influence of
the mycelium of the fungus.

PREVENTIVE MEANS. — The only known mode of repro-
duction of the fungus is by means of spores; hence all
fungi should be collected and either burned or buried.
Protect all wounds by applying a coat of tar.

The following Agarics also sometimes grow on living
trees : —

Pholiota aurivella (Batsch) resembles Pholiota adiposa
(Fries) in general appearance, but the stem is always dry,
not sticky. Often solitary.

Pholiota squarrosa (Mull.), densely tufted, dry, yellowish-
brown ; pileus and stem, up to the ring, ornamented with
projecting brown scales. Smell strong.

Pholiota destruens (Brond.). — Pileus dingy white or
yellowish, floccosely squamulose; stem whitish, squamu-
lose. On poplars.

Fig. 49. — Pholiota adiposa. i, cluster of fungi, a
pileus, b, stem ; about half nat. size ; 2, section of
pileus, a, a, lamellae or gills, b, b, the veil, which when
young extends as a membrane from the stem to the
margin of the pileus, and afterwards shrinks and forms
a more or less perfect ring round the stem, almost
obsolete in the present species ; 3, spores, x 300.

210 PLANT DISEASES

RASPBERRY ROOT ROT

(Hypholoma fasicnlare, Fries.)

This fungus, although exceedingly abundant, has not been
notified as a parasite in Europe. However, quite recently
Mr. D. M'Alpine, Government Vegetable Pathologist,
Melbourne, has announced that this species is very
destructive to raspberries in Victoria, forming a dense
white mycelium round the roots after the manner followed
by Armillaria mellea. Sour, damp soil favours the disease,
whereas drainage and the application of lime prevents its
spread.

The fungus grows in dense clusters on and around
rotten trunks, stumps, posts, etc. The general colour is
dingy yellow. The gills are yellowish-green, then clouded
with the dark-coloured spores. Taste very bitter, smell
acrid.

PREVENTIVE MEANS. — M'Alpine says drainage and
liming of the soil, together with the removal and burning
of diseased plants, are the principal measures to be relied
on. The addition of salt to the lime in the proportion of
two of lime to one of salt may be recommended.

USTILAGINACEAE

LOOSE SMUT OF OATS
(Ustilago avenae, Jensen.)

Popularly known as 'smut' or ' slean,' this disease is
known wherever oats are cultivated ; and before the
simple but certain preventive methods were discovered,

LOOSE SMUT OF OATS

211

Swingle estimates the annual loss at not less than
$18,000,000 for the United States alone.

The smut or mass of spores is produced in the ovary,

Fig. $o.—Ustilago avenae. i, a 'strutted' ear of oats;
2, spores, x3oo; 3, germinating spores, XSOQ; 4, secondary
spores conjugating, x 300.

and matures when the oat is in flower, and is dispersed
by wind or rain before harvest.

A form of this species called laevis, on account of the
smooth spores, has been recorded from America, growing

212 PLANT DISEASES

along with the typical form. In this hidden form the
chaff is not destroyed, and the spore-mass is concealed in
the grain.

Brefeld has proved that inoculation can only be effected
when the oat plant is quite in the seedling stage, immedi-
ately after germination. Smut spores adhering to the oat
seed germinate at this period, produce a promycelium,
which bears secondary spores, and these latter inoculate
the young oat plant, the germ-tubes entering its delicate
tissues, and grow along with the oat plant until its flower
is produced, when the fungus produces its spores under
the form of 'smut.'

PREVENTIVE MEANS. — The hot-water method is effective,
as is also steeping the seed in a solution of potassium
sulphide — ij pounds in 25 gallons of water — for twenty-
four hours, stirring thoroughly at intervals. A wooden
vessel should be used.

It has been definitely proved that by using either of
the above methods, a much greater increase in the yield
is obtained than would result by merely replacing the
smutted by sound grain.

Close has recently conducted an extensive series of
experiments, proving that sprinkling the seed grain with
a one per cent, solution of either lysol or formalin entirely
prevented the smut.

Brefeld, Nachrichten aus dem Klub der Landwirthen zu
Berlin, 1888, No. 220 et seq.

Jensen, Journ. Roy. Agrtc. Soc. England, vol. xxiv. pt. 2,
1888.

Rostrup, Nogle Undersogelser angaande Ustilago Carbo,
1890.

LOOSE SMUT OF WHEAT 213

Swingle, Year Book, U.S. Dept. Agric., 1894, p. 414.
Close, JV. York State Stat. Bui. 131, p. 441.

LOOSE SMUT OF WHEAT

(Ustilago tritid, Jensen.)

This fungus attacks the grain and also the chaff,
destroying the whole, and forming a loose black, dirty
mass, which usually disappears before harvest-time, leaving
only the stalk of the ear. The powder is not foetid.

Var. folicola (P. Henn.) develops on the leaf and leaf-
sheath of wheat, and is not uncommon in Egypt.

PREVENTIVE MEANS. — A difficult disease to combat, the
ordinary hot-water method not being effective, neither is
the bluestone method. Kellerman and Swingle state that
certain forms of hot-water treatment are effective, but
these injure the germinative power of the seed. The
safest method is to obtain seed from a locality free from
the disease.

MAIZE SMUT

(Ustilago mays zeae, Magnus.)

This disease appears to occur wherever maize or Indian
corn is cultivated, and has received attention from
scientists for a long time past, Brefeld, however, having
contributed most towards a correct knowledge of its life-
history. The disease usually appears first on the leaves,
and not before the plant is about a yard high ; afterwards
at the junction of leaf-sheath and blade ; finally the ear of
corn is attacked. In some instances one or other alone

214 PLANT DISEASES

of these parts is diseased. On the leaf the first evidence
of disease is the appearance of whitish wrinkled blisters,
usually surrounded by a reddish tinge of colour • at a later
stage the blisters burst and expose the mass of spores.
On the ear large, whitish, polished swellings appear,
reaching in size that of a walnut, and Brefeld states that
in an artificially infected ear the swelling reached the size
of a child's head. As the spores mature the swellings
become darker in colour, and the enclosing membrane
finally ruptures, exposing the dark olive-green mass of
spores.

The spores germinate readily at maturity, and produce
numerous very minute secondary spores ; and it is mostly
by means of these secondary spores that the disease
spreads so rapidly, inoculation taking place in the first
instance from spores that have remained over year
in the soil, or from secondary spores that have con-
tinued to propagate themselves by germination. Unlike
most other cereals, maize can be inoculated at any age,
so long as young growing tissue is present at any point.

PREVENTIVE MEANS. — It has been observed that smut
is most abundant where fresh manure has been used,
the spores probably germinating in the manure, and the
secondary spores continuing to reproduce themselves until
the maize is susceptible of infection.

Brefeld, Unters. aus dem Gesammtgebiete der MykoL,
Hefte iv., xi., numerous figs.

Norton, Kansas State Agric. Coll., Bull. No. 62, 10 pi.

Ustilago hordei, Jensen. — Attacks ears of cultivated
barley; the spore-mass is very hard and persistent, being

MAIZE SMUT

215

surrounded by the unbroken walls of the ovary, and fre-
quently remains intact after harvest. Steeping the seed in

1

Fig. 51.— Ear of barley attacked by Ustilago hordei.

a half per cent, copper solution prevents the disease, as
also does the hot-water treatment.

Ustilago nuda, Jensen. — This species also attacks culti-

216 PLANT DISEASES

vated barley, but differs from the last in the spore-mass
becoming pulverent and dispersed as soon as mature.

Very resistent to fungicides, and best treated with the
hot-water method, having previously been soaked for
several hours in cold water.

Ustilago sorghi. Pass. — Spore-mass forming in the ovary
of Sorghum vulgare and S. saccharatum, and completely
filling it with a dusty mass of spores. The anthers are
also attacked. As a rule all the flowers forming a head
are attacked.

Ustilago cruenta^ Kiihn. — This smut attacks the top of
the culm and branches of the inflorescence, rarely the
ovary of Sorghum vulgare, forming reddish-brown patches
and causing much distortion of the parts attacked.

Ustilago reiliana^ Kiihn. — Attacks Sorghum vulgare and
S. hahpense, and Zea mays in different parts of the world.
The ear is attacked, the spore-masses roundish or elongated,
at first enclosed inasilvery white membrane, then pulverulent
and soon dispersed, leaving only the more persistent parts
of the ear as a skeleton. Brefeld has experimented with
this species, and discovered that the spores germinate in
a nutritive solution after being kept for eight years. The
secondary spores also, if kept dry, retain the power of
germinating for a long time.

Ustilago emodensis, Berk. = Ustilago treubii, Solms. —
Professor Solms Laubach has given an interesting account
of this parasite — Ann. Jard. Bot. Buitenzorg, vol. vi. p. 79,
pi. ix. (1887) — but has overlooked the fact that it was
previously described by Berkeley — Hook. Journ. Bot.t vol.

SUGAR-CANE BRAND 217

Hi. p. 202 (1851). Clustered outgrowths up to one inch
long, longitudinally wrinkled, and capitate, are produced,
the violet spore-mass being formed in the swollen head or
apex of the outgrowths. Much hypertrophy and modifica-
tion of anatomical structure occurs at the diseased points.
Galls are also sometimes formed in the inflorescence.

The host is Polygonum chinense, and the disease is known
from India and Java.

Ustilago esculenta, P. Henn. — This fungus causes con-
siderable distortion or swelling of the stem of Zizania lati-
folia, and the diseased portions are sold as a vegetable in
the market of Hanoi, Tonkin. In Japan it is sold in the
apothecaries' shops under the name of Zizania — root-char-
coal ; the dark spores are used by those having thin eye-
lashes to make them look darker, and mixed with oil they
are used by women having thin or grey hair. The spores
are also much used in Japan in the lacquer industry, to
produce rust-coloured ware when mixed with lac.

Miyabe, Bot. Mag., vol. ix. No. 99, 1895.
Hennings, Hediv., vol. xxxiv. p. 10, 1895.

SUGAR-CANE BRAND

(Ustilago sacchari, Rabenh.)

The leaves are attacked, more especially the upper ones,
while yet unexpanded and embracing each other, the
whole being converted into a projecting, discoloured,
tendril-like production.

Wakker and Went, De Zeiktin van Het Suikerriet op
Java, p. 24, pi. 2.

2i8 PLANT DISEASES

STINKING SMUT OF WHEAT

( Tilletia tritid, Winter.
= Tilletia caries, Tulasne.)

A destructive fungus to the wheat crop, inoculating the
young plantlet, and growing along with it without produc-
ing any external evidence of its existence, except perhaps
just a deeper tinge of green in the leaves, until the wheat
is in bloom, when the rigid, erect ear and spreading florets
and scales betray the presence of the parasite. The spores
are produced in the ovary or grain, and, as a rule, every
grain in the ear is diseased. When mature the mass of
spores liberated on crushing a diseased grain between the
fingers is black, with a tinge of olive, and possesses a very
strong, disagreeable smell, somewhat resembling rotten
fish, especially when moistened.

The spores are always produced at the tips of branchlets
of mycelium, which do not become gelatinised. The epi-
spore, or outer wall of the spore, is furnished with thin
raised ribs, which are so arranged as to form a network
on the surface of the spore. Germination takes place
readily when the spores are placed on a damp surface, an
elongated promycelium being produced in the air, which
bears a tuft of 7 to 12 narrow, elongated, secondary spores
at its apex. These secondary spores usually become con-
nected in pairs by the outgrowth of a narrow neck from
one to the other, and when completed resemble the letter
H. The secondary spores that fuse in pairs germinate at
once, some producing a very slender thread or branch of
mycelium ; others give origin to curved sporidia, which in
turn emit a delicate germ-tube. Both these conditions

STINKING SMUT OF WHEAT

219

are capable of entering the tissues of a very young wheat
plant.

Fig. %2, — Tilletia tritici. i, ear of wheat
diseased ; 2, spore, x 300 ; 3, 4, spores ger-
minating and producing a germ-tube bearing a
cluster of secondary spores at the tip, x 300; 5,
two secondary spores that have conjugated or
become united by a short, transverse neck ; one
of the secondary spores has produced a coni-
dium, x 300 (3-5 after Brefeld).

The secondary spores produced in the air germinate
readily in a nutritive solution as saprophytes, forming a

220 PLANT DISEASES

copious mycelium and numerous conidia. This mode of
reproduction is capable of developing and increasing for
some time under favourable conditions, as in a manure-
heap ; such infected manure, if used on land where wheat
is to be sown, commences the disease.

PREVENTIVE MEANS. — The hot-water method, taking
everything into consideration, is best. Corrosive sublimate
(mercuric chloride) is also efficacious in preventing the
disease. The grain should be sprinkled with a solution of
one. pound of corrosive sublimate to fifty gallons of water;
the wheat should be raked or shovelled about till the surface
of every grain is wet all over. Metal must not come in
contact with the solution, which is poisonous, and should
be used with care.

Bolley and Close, American experimenters, have dis-
covered that formalin (a forty per cent, of formaldehyde),
used at the rate of one pound to fifty to sixty gallons of
water, is effective against stinking smut of wheat and
loose smut of oats. The seed should be soaked two
hours.

Wheat sown in the spring is invariably more 'smutted'
than when sown in the autumn.

Brefeld, Unters. aus dem Gesammt. der MykoL, v. Heft,
p. 146, Taf. xii.-xiii., figs. 25-52 (1883).

Tilletia /em's, Kiihn = Tilletia foetens, Arthur. — De-
veloped in the grain of wheat, like T. tritici, which it
resembles in appearance and smell, but differs in the
perfectly smooth spores. This speoies appears to be most
abundant of the two in the United States, whereas it is
rare in Europe. Treatment same as for Tilletia tritici.

RYE SMUT 221

Tilletia dedpiens, Winter = Tilletia secalis, Kiihn.—
Spore-mass blackish-brown, formed in the ovary in rye,
also in several wild grasses. The Agrostis pumila of
Linnaeus is nothing more than Agrostis vulgar is dwarfed
by this Tilletia.

RYE SMUT

( Urocystis occulta, Rabenh.)

This smut is most abundant on rye, but also occurs less
frequently on oats and barley, and has been met with on
wheat in Australia, according to Wolff.

It forms long grey lines on the leaf-sheaths, leaves, and
upper part of the culm. When the epidermis, which for
some time covers the spores, is ruptured, the streaks are
black and powdery. In diseased plants the tissues are
more or less destroyed and deformed, the ear is arrested in
its development, and the culm often bends over at the
point attacked.

The spores are in small clusters, two to three central
ones, thick-walled, dark-coloured, and fertile, surrounded by
several pale, sterile cells. On germination a germ-tube is
formed, which bears at its tip a whorl of cylindrical,
secondary spores, each of which on germination gives origin
to a slender germ-tube from its basal end. These germ-
tubes inoculate the host-plant by penetrating its tissues
when in the youngest condition, soon after sprouting.
Inoculation cannot be effected at a later stage of growth
of the host.

PREVENTIVE MEANS. — Jensen considers that this smut

222

PLANT DISEASES

can be prevented by immersing the seed for five minutes in
hot water at 127° F.

Fig. 53. — Urocystis occulta. i, upper part of a rye
plant diseased; 2, spores, one of which- has germinated
and produced a cluster of secondary spores at the apex of
the germ-tube, X3oo; 3, a spore that has germinated
and produced secondary spores, two of which have
germinated, a, x 300.

Prillieux, Mai ad. des Plantes Agric., vol. i. p. 187, figs.

ONION SMUT 223

ONION SMUT

(Urocystis cepidae, Frost.)

This disease is up to the present only known to attack
the cultivated onion, and develops during the seedling stage
of the host. As a rule, the first leaf shows the disease before
the second leaf is developed, generally appearing on succes-
sive leaves in the order of their development ; the outer tunic
of the bulb eventually becomes infected. When the fungus
is mature, the epidermis is ruptured and the spores appear on
the surface under the form of large, black, powdery streaks.

Sometimes the first leaf alone is attacked, when the
plant continues to grow ; if more leaves are attacked, the
seedling soon perishes.

White varieties of onion appear to be most susceptible
to the disease.

PREVENTIVE MEANS. — The spores are shed on the
ground in immense numbers, and great care should be
taken not to transport such infected soil to new and
uninfected localities by means of tools, shoes, etc. It is
highly probable that the seedlings are infected by smut
spores present in the soil at the earliest stage of growth,
and cannot be infected at a later stage ; hence it is
recommended that onions should be transplanted, for even
if planted in ground containing smut, the plants remain
free from the disease owing to the period of possible
inoculation having been passed. Furthermore, apart from
the disease, it is maintained that transplanted onions yield
a better crop and mature earlier than onions that have not
been transplanted. All diseased plants should be collected
when the onions are being weeded and thinned. Where
soil has become infected with smut-spores, onions should

224

PLANT DISEASES

not be sown for some years. The disease appeared in one
instance after a period of twelve years' rest, due presumably
to smut-spores still present in the soil.

Thaxter, Ann. Rep. Conn. Agric. Expt. Station, p. 129,
pi. 2 (1890).

Weed, Fungi and Fungicides, p. 152.

COLCHICUM SMUT

( Urocystis colchici, Rab.)

This smut often forms long rows of black, powdery
streaks on the leaves of Colchicum (Colchicum autumnale\

Fig. 54. — Urocystis colchici. i, Portion of a diseased leaf,
nat. size; 2, a single sorus, slightly mag. ; 3, spores, X3oo.

Muscari racemosum, M. comosum, Scilla bifolia, Allium
rotundum, A. cepa, A. magicum, and Paris quadrifoiia.

POTATO SCAB 225

POTATO SCAB

(Sorosporium scabies, Fisch. de W.)

This disease forms large olive scabs or rough patches on
the surface of nearly full-grown potatoes. It is not very
injurious, and in fact is often considered as a sign that the
potato attacked is good and floury. When present in large
quantity the market value is depreciated. Adding lime to
the soil is said to prevent the disease.

BEETROOT TUMOUR

(Oedomyces leproides, Trabut.
= Urophlyclis leproides, P. Magnus.)

Beetroot — Beta vulgaris, var. rapacea — growing in the
grounds of the School of Agriculture, Rouiba, near Algiers,
was attacked by a disease not previously recorded. Large
nodulose or brainlike outgrowths develop near the apex
of the root, and may consist of modified leaves or rootlets;
the tumours are fleshy, attached to the root by a short,
narrow neck, and in the substance are numerous cavities
filled with dark-coloured spores. The spores are subglobose,
produced at the apex of a hypha, which bears a large
vesicular swelling just below the spore.

PREVENTIVE MEANS. — As resting-spores are formed, all
diseased material should be removed from the soil and
burned.

Trabut, Rev. G'enerale de Bot., vol. vi. p. 409, i pi. (1894).
Saccardo and Mattirolo, Malpighia, vol. x. (1895).
Magnus, Ann. Bot., 1897, p. 87, 2 pi.

P

Fig. 55. — Oedomyces leproides. i, a diseased beetroot
2, a spore, XSQO (after Trabut).

COLCHICUM SMUT

227

UEEDINACEAE

COLCHICUM SMUT
( Uromyces cokhiri, Massee.)

For three successive seasons the foliage of a bed of
Colchicum speciosum was completely destroyed by this
fungus, and during the third season plants of Colchicum
bavaricum and C. autumnale growing on either side of the

Fig. 56.— Uromyces colchici. i, portion of a diseased
Colchicum leaf; 2, a sorus or cluster of spores which
has ruptured the epidermis of the host-plant, x 10 ;
3, teleutospores, consisting of several cells united in a
cluster ; the central dark cells are fertile, the pale, peri-
pheral cells are sterile, x 300.

diseased patch were also attacked, although escaping for
the first two seasons. The parasite attacks the leaves
only, commencing at the base of the leaf-sheath and
gradually extending towards the tip of the leaf. The lowest
and oldest leaf is first attacked.

The sori or spore-clusters are very much larger than is

228 PLANT DISEASES

usual in the genus, often elongated when growing on the
leaf-sheath, whereas on the leaf the spots are usually
arranged in circular groups. The sori remain for a long
time covered by the epidermis of the leaf, which is finally
ruptured, exposing the conspicuous black spore-masses.
Teleutospores are alone known, and these remain dormant
during the winter, germinating the following spring.

PREVENTIVE MEANS. — A portion of the plants sprayed
with a deep rose-coloured solution of potassium perman-
ganate ( = Condy's Fluid) just when the leaves appeared
above the soil, and twice later, at intervals of ten days,
remained free from disease, adjoining unsprayed plants
being badly infected.

Diseased leaves should not be allowed to rot on the
ground ; and if the plants become diseased, it is advisable
to remove the bulbs to some locality where the soil is not
infected with teleutospores.

BEET RUST

(Uromyces betae, Kiirm.)

The leaves of beetroot and mangold are often infested
with rust to such an extent that the value of the crop is very
considerably reduced. The cluster-cup or aecidium stage
is the first to show itself; the cups have whitish, torn edges,
and occur in groups on yellowish spots. These are followed
in June by the uredo stage. Finally, the crowded, blackish-
brown pustules of teleutospores follow in August, and con-
tinue to develop until the leaves fade in the autumn.

PREVENTIVE MEANS. — Spraying early in the season with
dilute Bordeaux mixture or solution of potassium sulphide
will arrest the spread of the disease.

The usual difficulties attend an attempt to avoid a re-

BEET RUST

229

petition of the disease. When the crop is lifted, the leaves,
covered with teleutospores, often find their way into the
piggery or cattle-fold, whence many of the teleutospores
eventually find their way back to the field along with

Fig. 57. — Uromyces betae. i, portion of a mangel leaf,
spotted with the teleutospore stage ; 2, portion of a leaf
showing a white patch crowded with aecidia, x 6 ; 3,
section of portion of a leaf showing two clusters or son of
uredospores, xjo ; 4, aecidiospores, xyx> ; 5, uredospores,
X3oo; 6, teleutospores, X3OO.

manure. If the leaves are left to rot in the field the case
is no better.

The fungus also occurs on wild beet, and from thence
has been proved to pass on to cultivated crops.

BKOAD BEAN RUST

( Uromyces fabae, De Bary.)

This parasite is very common on the leaves and stems
of broad beans, peas, also on several wild leguminous
plants, as vetches, etc. The aecidium stage is the first to

230 PLANT DISEASES

appear in the spring; the cups are grouped on conspicuous,
thickened, whitish spots on the stem and leaves. The
uredo stage follows under the form of minute brown spots,
often thickly scattered over the surface of the leaf. Finally,
the teleutospores are developed from midsummer to the
end of November as roundish or elongated spots on stem
and leaves. The uredospores germinate when mature, and
spread the disease, whereas the teleutospores germinate the
spring following their formation, and produce the first or
aecidium condition.

PREVENTIVE MEANS. — Spraying with dilute Bordeaux
mixture arrests the spread of the disease. In dealing with
small quantities, as in gardens, spraying with potassium
permanganate or potassium sulphide effects the same
object. It must be remembered that the disease originates
in the spring from floating secondary spores produced by
germinating teleutospores that passed the winter on the
leaves or stems ; hence infected plants should be burned
as soon as the fruit is gathered, and not allowed to stand
or lie on the ground throughout the winter. In the case
of field crops these facts also apply, although it is difficult
to suggest a practical remedy ; but it is almost certain that
if the straw eventually finds its way to the manure-heap,
many of the teleutospores will survive until the manure is
used, and if this happens to be in a field sown with beans
or peas, infection of the crop will follow.

Wild vetches should not be allowed to grow in hedges
or waste places.

HARICOT BEAN RUST

( Uromyces appendiculatus, Link.)

Haricot beans or ' scarlet-runners ' are often much injured
by this pest. All three stages — aecidia, uredo, and teleuto-

COFFEE LEAF DISEASE 231

spores — develop on the leaves. The two latter often form
myriads of little pustules which cause the leaves to fall
early, and thus the development of fruit is checked.

PREVENTIVE MEANS. — Spraying with potassium sulphide
solution, if commenced sufficiently early, might be bene-
ficial, although I am not aware of its having been tested.
Fallen leaves bearing teleutospores should be gathered and
burned.

COFFEE LEAF DISEASE

(Hemileia vastatrix, Berk, and Broome.)

This terrible scourge, which was first observed in small
quantity on a single estate in the Mandulsima district,
which occupies the south-western portion of the hilly
country of Ceylon, is now widely distributed — India,
China, Malay Peninsula, East Indies, Philippines, Natal,
German East Africa, and probably wherever coffee is
cultivated in the Old World.

The leaves are most frequently attacked, spots being
also sometimes present on young shoots and even on the
fruit.

On the leaves the earliest stage of the disease is indicated
by the presence of more or less circular, discoloured spots.
These continue to increase in size for some time, retaining
their irregularly circular outline, become pale yellow, and
studded with bright yellow clusters of spores, which soon
change to a bright orange colour. The patches show on
both surfaces of the leaf, but the spores are confined to the
under surface.

The spores are produced in dense clusters on the tips
of hyphae which come to the surface of the leaf through
the stomata. Those surfaces of the spore that are in con-

232 PLANT DISEASES

tact when the spores are growing are smooth, whereas the
outer, free portion of the surface is coarsely warted.

PREVENTIVE MEANS. — Very little success in this respect
attended the efforts of those investigators of the disease,
whose primary object was to discover, if possible, some

Fig. 58. — Hemileia vastatrix. i, portion of a coffee leaf
showing diseased patches ; 2, a patch showing sori or
clusters of spores, slightly mag. ; 3, spores, x 350.

means of checking the epidemic. Probably some of the
modern fungicides, as Bordeaux mixture, etc., might prove
more effective. Diseased leaves should be collected and
burned on all occasions.

Full notes respecting the distribution of the different
species of Hemileia^ along with the dangers arising from
want of discrimination in the selection of 'shade trees,'
will be found on p. 27 of this book.

Berkeley, Card. Chron., p. 1157 (1869).
Morris, The Coffee Leaf Disease of Ceylon and Southern
India.

WEYMOUTH PINE RUST 233

Marshall Ward, Sessional Paper s> xvii., Colombo, Ceylon,
1881.

WEYMOUTH PINE RUST

(Crtmartium ribicolum, Deitr.
= Peridermium strobi, Kleb.)

The aecidium stage of this fungus occurs on living bark
of the Weymouth pine (Pinus strobus), and has also been
recorded as occurring on Pinus lambertiana and P.
cenibro. The large aecidia burst through the bark in
considerable numbers, are pale yellow, and contain
minutely warted, subglobose, orange spores. These spores
when placed on living leaves of the black currant (Ribes
nigruvi), also R. aureum and R. alpinum^ germinate and
produce, in the first instance, crowded pustules of uredo-
spores ; afterwards, from the centre of each uredo pustule,
a very slender, hairlike body about one line long springs
up, composed of a mass of teleutospores, which germinate
without falling away ; each teleutospore gives origin to one
germ-tube which bears three or four minute secondary-
spores near its tip. These secondary spores in turn give
origin to the aecidium stage on pine bark. Spermogonia
alone are formed the first year after infection, the aecidia
the following year. The stage on currant leaves was at
one time considered as an independent fungus called
Cronartium ribicolum.

It is somewhat remarkable that, so far as at present
known, this fungus is absent from America, the home of
the Weymouth pine.

PREVENTIVE MEANS. — Requiring the two hosts for its

234

PLANT DISEASES

continuance, the only course is to remove the one con-
sidered as of least value.

JX /?>C^

./•

Fig. 59. — Cronartium ribicolum, i, uredo and teleuto-
spore stages on leaf of black currant ; 2, uredospores,
a, and teleutospores, b, cemented together to form an
erect, hairlike structure, XSQ; 3, uredospore, XSDO;
4, four teleutospores, two of which are germinating, and
one of the germ-tubes has produced four promycelium
or secondary spores, x 300 ; 5, aecidia on bark of Wey-
mouth pine ; 6, aecidiospores, x 300.

Rostrup, Bot. Centralb. xliii. p. 353.

Prillieux, Malad. des Plantes Agric., vol. i. p. 275.

PINE BLISTER-BLIGHT 235

PINE BLISTER-BLIGHT

(Cronartium asclepiadeum, Fr.
=. Peridermium cornm, Rostr. and Kleb.)

The aecidia occur on the bark of Scots fir (Pinus silves-
tris), and produce effects very similar to those described
under Peridermium pini.

The hairlike bundles of teleutospores and uredospores
grow on the under surface of the leaves of Cynanchum
vincetoxicum.

Supposed varieties of this species occur on oaks
(Quercus nigra and Q. tinctoria), also on Comandra umbel-
lata and C. pallida in the United States, also on leaves of
Asclepia speciosa in France.

Prillieux, Malad. des Plantes Agric., vol. i. p. 271, figs.

Cronartium flaccidum, Winter. — Uredospores and teleuto-
spores on the under surface of leaves of cultivated paeonies.
Aecidial condition unknown. Other species are also known,
in which the aecidia are not yet known.

PINE BRANCH TWIST

(Melampsora pinitorqua, Rostrup.
= Caeoma pinitorquum, A. Br.)

The aecidium condition of the present fungus has been
proved by Hartig to be very destructive to young pines,
seedlings being sometimes diseased when just appearing
above ground, whereas at the age of about thirteen years
the disease dies out, and plants that have not been too

236 PLANT DISEASES

severely attacked up to that period recover. Plants that
become diseased when quite young are usually killed, as
the disease appears year after year, if the weather is damp
in May and June, suggesting that the mycelium is per-
manent in the tissues of the host.

In a seed-bed or young plantation it is observed that
the disease spreads centrifugally from a centre, infection
being effected by wind-borne spores, which leads to the
conviction that the aecidiospores can perpetuate the
disease on pines. Spermogonia and aecidia appear on
the leaves or young shoots, the cortex of the latter becom-
ing orange-colour. Growth of the branch is checked at
the part diseased, whereas it continues at other points ;
the result of this unequal growth resulting in a curvature
of the branch, and as the tip of the branch tends to grow-
upwards, double curves are the result.

Rostrup demonstrated by experiment that the teleuto-
spores of a fungus supposed at one time to be a distinct
species called Melampsora fremulae, Tul., growing on dead
leaves of the aspen (Populus tremula\ when caused to
germinate on the leaves or shoots of young pines, gave
origin to the condition called Caeoma pinitorquum, also
previously considered as an independent fungus. He also
produced the uredospore and teleutospore stages on aspen
leaves by inoculation with aecidiospores formed on the
pine.

PREVENTIVE MEANS. — Badly diseased plants should be
removed from seed-beds. Aspens should not be allowed
to grow in the neighbourhood of nurseries or young planta-
tions of pines.

During seasons favourable to the growth of the fungus
on the aspen, its leaves are often quite yellow with the

PINE BRANCH TWIST

237

uredospores during the summer, and consequently fall off
before the normal time. The flat, compact, crustlike
patches of teleutospores develop on the fallen, dead leaves,
and germinate the following spring.

Fig. 60. — Melampsora pinitorqua. i, top of a young pine attacked by
the aecidium stage; 2, two chains of aecidiospores, X4oo; 3, aspen leaf
with pustules of teleutospores ; 4, section through a pustule of teleutospores
still covered by the epidermis of the leaf, x 400.

Hartig, Bot. Centralb., xxiii. p. 362 (1885).

Hartig and Somerville, Diseases of Trees, p. 166, figs.

Prillieux, Malad. des Plantes Agric., vol. i. p. 286, figs.

238 PLANT DISEASES

LARCH LEAF RUST

(Melampsora laricis^ Hartig.
= Caeoma lands ^ Hartig.)

The aecidium stage of this fungus forms yellow pustules
on the leaves of the larch ; as a result the leaves wither and
fall. The branches are not attacked. The uredospore
and teleutospore conditions grow on the leaves of poplars
(Populus tremula, and P. nigrd).

For reasons that cannot be discussed here, it appears
highly probable that this fungus is specifically identical
with Melampsora pinitorqua, the slight differences observ-
able being due to the different host on which the fungus
grows. Melampsora betulina also probably belongs to the
same category.

Hartig, Allgem. Forst und Jagd. Zeit. 1885, p. 356.
Prillieux, Malad. des Plantes Agric., vol. i. p. 292.

FLAX RUST

(Melampsora lini^ Tul.)

The rust is often very destructive to cultivated flax (Linum
ttsifatissimum), and is widely distributed in Europe ; it also
occurs in Australia and the United States. The uredo sori
form small orange spots on the stem, leaves, and some-
times on the sepals. The teleutospore sori form large,
smooth, blackish patches on the stem, sometimes almost
covering and blackening it all over. The teleutospores
are densely crowded side by side, and are covered by the
epidermis of the host. Various other species of Linum
are also attacked, and this is important to bear in mind.

ASPARAGUS RUST 239

Our little purging flat (Linum catharticuni), so abundant in
many pastures, is often orange with the rust, the spores
from which would readily infect any crop growing in the
neighbourhood.

Stems covered with teleutospores should be burned,
otherwise the disease is liable to be perpetuated.

ASPARAGUS BUST
(Pucctnia asparagi^ D. C.)

Too frequently the entire crop of asparagus in a given
district is destroyed by this minute parasite, and quite
recently the disease has suddenly appeared, and done an
unparalleled amount of mischief to asparagus, in the United
States.

The disease usually appears rather late in the season,
after the greater portion of the crop for the year has been
gathered, but not unfrequently the aecidium stage of the
fungus appears on the earliest shoots. This is followed
by the brown pustules of the uredo stage on the stem and
branches ; later in the season black streaks, numerous black
spots, and streaks of teleutospores appear, often in such
quantity as to blacken the stem and branches. This
destruction of the entire plant means an inferior crop the
following season, also a diseased one, unless prompt
measures for its prevention are carried out.

PREVENTIVE MEANS. — The appearance of the disease in
the spring depends on teleutospores in the neighbourhood ;
consequently it is of primary importance that all diseased
plants should be gathered and burned, otherwise many
teleutospores find their way to the ground.

240

PLANT DISEASES

After the crop is gathered, the summer plants might be
sprayed with Bordeaux mixture to keep the fungus in check ;

Fig. 61. — Puccinia asparagi. i, aecidium stage on a
young shoot of asparagus ; 2, teleutospore condition on a
summer plant; 3, aecidiospores, XSOQ; 4, uredospores,
5, teleutospores,

but the important point is to remove diseased plants, and
so by degrees prevent the possibility of infection in the
spring.

MINT RUST

(Puccinia menthae, Pers.)

Whole beds of garden mint, especially when growing in
damp, shady situations, are often completely destroyed by
this parasite, which also occurs on several species of wild
mint, and other Labiate plants.

All three conditions of the fungus develop on the same
host. The orange aecidia or cluster-cups appear first in
the spring, and are most abundant on the stems, which
become swollen and much twisted and distorted.

CHRYSANTHEMUM RUST 241

The uredospores and teleutospores appear later in the
season, mostly on the leaves, the former as pale brown
pustules, which soon become powdery ; the latter form
blackish-brown powdery pustules.

PREVENTIVE MEANS. — When plants are once attacked,
cure is practically impossible, as the mycelium is perennial
in the plant, passing the winter in the part below ground,
and growing up, year by year, with the new stems.

If the disease appears, infected plants should be dug up
at once, and burned, care being taken to remove all the
underground parts, otherwise the disease will appear again
with the new shoots.

CHRYSANTHEMUM RUST

(Puccinia hieracii> Mart.)

A specimen of a supposed new disease of cultivated
chrysanthemums was sent to Kew for examination by the
editor of the Gardeners' Chronicle in 1897. During the
remarkably dry summer of 1898 this disease spread to
such an alarming extent in the south of England and in
parts of France that cultivators of this favourite flower,
remembering the wave of fungous disease that rendered
the successful cultivation of the hollyhock a matter of
impossibility for some years, predicted for it a similar fate.
Fortunately the exercise of prompt measures averted such
a catastrophe.

The uredo or summer fruit forms minute, snuff-coloured
clusters of spores on the under surface of the leaf. In
badly diseased examples the pustules are often so numerous
as to cover the greater part of the surface of the leaf.
Unless checked, this stage of the fungus reproduces and

0

242 PLANT DISEASES

extends itself throughout the summer months. When the
leaves are fading, the teleutospore form of fruit is produced,
which differs from the uredo form in the pustules being
darker in colour, and not powdery. The aecidium stage
is absent.

The teleutospore stage has not up to the present been
observed on the chrysanthemum, and some observers
consider the uredo as belonging to Pucdnia tanaceti.

PREVENTIVE MEANS. — Spray at intervals, dating from
the growth of new leaves, with potassium sulphide solution,
which not only destroys the rust-spores, but also those of
various other fungous pests that attack chrysanthemums.
Remove plants showing the slightest trace of disease.

If the disease has existed, be careful to destroy all leaves
that may be likely to produce teleutospores, otherwise a
recurrence of the disease is practically certain. In the
case of plants grown in houses, the uredo form will continue
throughout the winter on the living leaves, therefore a
constant watch for the fungus is necessary.

Finally, this fungus is by no means uncommon on a
score or more wild species of plants belonging to the
Compositae, and care should be taken not to allow the
disease to be introduced by such outside sources • the
fungus is especially common on wild species of hawkweed
(Hieracium), hence its specific name.

There is no reason why this fungus should not, in
course of time, attack other cultivated composite plants,
as cinerarias, dahlias, etc.

Massee, in Gardeners' Chronicle, and Gardeners' Maga-
zine, with figs., Oct. 8th, 1898.

GOOSEBERRY LEAF CLUSTER-CUPS

243

GOOSEBERRY LEAF CLUSTER-CUPS

(Puccinia pringsheimiana, Klebahn.)

During certain seasons the leaves, and sometimes also
the fruit, of the gooseberry are studded with little groups
of cluster-cups seated on a red or orange patch. When

Fig. 62. — Puccinia pringsheimiana. i, portion of a gooseberry leaf
with three aecidia or ' cluster-cups ' fully expanded, x 15 ; 2, section through
a single cluster-cup showing, at a, the spores, produced in chains, which
afterwards separate into single spores, filling the cup with a yellow powder ;
b, the protective wall or peridium ; c, epidermal cells of the leaf ; d, the
middle cells of the leaf ; e, the mycelium of the fungus running between
the cells of the leaf, xsoo ; 3, portion of the leaf of a sedge, bearing the
sori or minute clusters of uredospores and teleutospores ; 4, a portion of
fig. 3, x 15 times ; 5, teleutospores, XSOQ ; 6, uredospores, X3oo.

mature the cups have White, torn edges, and are filled with
orange spores. The uredo and puccinia forms of the
fungus have only quite recently been identified ; they grow
on the leaves of sedges (Carex).

PREVENTIVE MEANS. — As a rule the fungus does not

244 PLANT DISEASES

appear in sufficient quantity to do any harm. Removing
the infected sedges will prevent its appearance.

Klebahn, Zeitschr. f. Pflanzenkr^ vol. v. p. 76 (1895).
Smith, Gard. Chron.^ vol. xvi. p. 76, 1881, figs.

GRAIN RUSTS

Notwithstanding the combined efforts of scientists and
practical men in various countries to devise some method
for preventing the enormous amount of damage to our
cereals caused by fungi belonging to the genus Pucdnia,
the problem yet remains unsolved. Nevertheless, a large
amount of valuable information has been acquired, and it
is generally acknowledged that we are now in possession
of two general principles bearing on the subject : (i) that
from the present standpoint of knowledge, spraying with
fungicides is of no practical value in preventing rust; (2)
that the production of rust-resisting varieties of wheat
should be aimed at, the results of experiments already
accomplished in this direction being most encouraging.

The essential points that collectively contribute to form
rust-proof varieties are : toughness of the epidermis of the
leaf; leaf narrow, fairly rigid, and erect, or nearly so.

Early sown and early ripening varieties escape rust
best.

Top-dressings of nitrate of soda (Chili saltpetre) make
the foliage soft and broad, and consequently more suscep-
tible to rust. Nitrate of soda retards ripening, and thus
favours rust.

The following is from Dr. Eriksson's latest resume of his
researches on the grain rusts. There are at least ten kinds
of fungus which cause rust in cereals, partly species, partly

GRAIN RUSTS 245

specialised forms of species. In addition to growing on
cereals, these fungi are also met with on numerous wild
grasses ; Puccinia graminis occurs on a hundred different
grasses in Sweden. It was considered until quite recently
that the cereals could be infected by the spores of a rust
produced on any wild grass. This is not the case, but as
a rule the various forms are almost exclusively confined to
one host, and are unable to infect any other cereal but
that one. Thus stems of oats bearing black rust can
propagate black rust to oats, but not to rye, wheat, or
barley ; stems of rye bearing crown rust can propagate
crown rust to rye, but not to wheat ; and so on. Plants of
rye and barley attacked by black rust make an exception
to this rule, as they are able to infect one another; in
some cases also those of wheat propagate black rust to
other cereals.

The propagation of rust is often slight between grasses
capable of serving as a host to the same specialised form.

The germinating power of uredospores and aecidiospores
is often small, or at best capricious. It was discovered
that chilling the spores by putting them on ice or in cold
water for several hours increased the power of germination.

The germinating power of teleutospores depends upon
certain external conditions, and is restricted to a short
period of time, and it appears that only the crop of teleuto-
spores maturing during late autumn is able to germinate
the following spring.

All the modes of propagation enumerated appeared
inadequate to account for the enormous amount of rust
usually present, and the following observations led Eriksson
to formulate a theory of the occurrence of rust to another
cause than that solely due to infection by spores : —

246 PLANT DISEASES

a. The yellow rust appears in certain varieties of wheat
and barley that are especially susceptible, uniformly four
to five weeks after sowing.

b. The intensity has sometimes been stronger in sunny
than in shady places in the same wheatfield.

c. Plants of a variety of barley extremely susceptible to
yellow rust, grown in sterilised soil, and protected from
external infection in isolated glass-houses, have sometimes
become rusted.

1 These results prove beyond doubt that the disease
must come from internal germs inherited from the
parent plant. But in what form are these internal
germs of disease living? Is it easy to follow and identify
them with the microscope ? Not at all. They can only
be detected just before the breaking-out of the young
pustules. The microscope examination induces me to
suppose that —

' The fungus lives for a long time a symbiotic life as a my co-
plasma in the cells of the embryo and of the resulting plant,
and that only a short time before the eruption of the pustules,
when outer conditions are favourable, it develops into a visible
state, assuming the form of a mycelium.''

Eriksson, Bot. Gaz., vol. xxv. p. 26 (1898).

It has been proved experimentally that rust-shrivelled
wheat used as seed produces as good a crop, and one as
free from rust, as when plump seed is used. If Eriksson's
theory is correct, it is not wise to sow rust-shrivelled grain
for seed, as probably the amount of rust produced may be
due to the internal mycoplasma, consequently more grain
is produced which presumably would contain mycoplasma,
and if this should be used as seed the same thing would

BLACK RUST 247

be repeated. There is also a danger of infection by spores
produced by the crop ; a condition accepted by Eriksson,
if only to a limited extent,

The following literature may be consulted as bearing on
the subject : —

De Bary, Mon.-Ber. der -Akad. der Wiss. zu Berlin, Sitz.
1 2th Jan. 1865.

Cobb, Agric. Gaz. N.S. Wales, vol. i. No. 3 ; vol. iv.
No. 6.

Eriksson and Henning, Die Getreideroste, 1896.

Marshall Ward, Ann. Bot., vol. ii. No. 6, 1888.

M' Alpine, Dept. Agric. Victoria, Bull. 14, 1891.

Farrer, Dept. Agric. N.S. Wales, No. 206 (1898).

BLACK RUST

(Puccima graminis, Pers.)

This universally distributed species is the one most
injurious to cultivated cereals, attacking wheat, oats, barley,
and rye, but is most general on wheat. It is also common
on numerous wild grasses, occurring on one hundred
different species in Sweden alone, according to Eriksson.

The aecidia occur in clusters seated on orange spots on
living leaves, young shoots, flowers, and fruit of various
species of barberry — Berberis — and the allied genus
Mahonia. The uredo and teleuto spore conditions form
small streaks on the leaf-sheath, leaf, culm, and less fre-
quently on the chaff of grasses. The uredo streaks are
rusty orange • the teleutospore streaks, which appear later
in the season, blackish. An account of the life-cycle of
this species is to be found at p. IT.

Fig. 63. — Puccinia graminis. i, leaves of wheat plant with rust
pustules of the uredo stage ; 2, a rust or uredo sorus, or group of spores,
x 10 ; 3, uredospores in various stages of development, xsoo; 4, uredo-
spore germinating, x 300 ; 5, portion of culm of a wheat plant showing the
dark streaks formed by the sori of the teleutospore stage on the sheath of
a leaf; 6, teleutospores in various stages of development, X3oo; 7, a
teleutospore that has germinated and produced a germ-tube bearing three
secondary spores, X4Oo; 8, a barberry leaf bearing several clusters of
aecidia ; 9, section of an aecidium showing the pseudoperidium or external
protective covering, a, enclosing numerous chains of aecidiospores, x 300;
10, two aecidia seen from above, slightly mag. ; n, sporules on sterigmata
from a spermogonium, x 300.

CROWN RUST 249

CEOWN RUST

{Puccinia coronata, Corda.)

A widely distributed rust, characterised by the apex of
the teleutospore being ornamented with a varying number
of blunt projections. The aecidia form irregular yellow
patches on the under surface of living leaves, also some-
times on the flowers and fruit of various species of buck-
thorn— Rhamnus.

The uredo and teleutospore stages occur on the upper
surface of the leaves, less frequently on the leaf-sheath,
culm, and chaff.

The minute black teleutospore sori often form irregular
rings.

Met with on wheat, barley, rye, and many wild grasses.

Puccinia phki-pratensis, Eriks. and Henn. — This species
in a wild state occurs on Timothy grass — Phleum pratense
— but artificial infection has proved that it can inoculate
cultivated cereals. The aecidium stage is unknown.

Puccinia glumarum, Eriks. and Henn. = Puccinia rubigo-
vera, D. C. — A widely distributed and destructive species,
attacking wheat, barley, oats, and many wild grasses.

Aecidium stage unknown. Uredo and teleutospore
conditions develop on the leaves and inner side of the
chaff. Teleutospore sori accompanied by paraphyses.

Puccinia dispersa, Eriks. and Henn. — The aecidium forms
irregularly elongated patches on living leaves, stems, flowers,
and fruit of Alkanet — Anchusa arvensis and A. officinalis.
Uredo and teleutospore stages on the leaves of wheat, rye,

250 PLANT DISEASES

and wild grasses belonging to the genera Bromus, Trisetum^
and Triticum. Paraphyses are present in the teleutospore
sori.

Puccinia simplex, Eriks. and Henn. — Aecidium unknown.
Uredo and teleutospore conditions on leaves of barley.
Paraphyses are present in the teleutospore sori.

CELERY LEAF RUST

(Puccinia bullata. Winter.)

This fungus forms small warts on the leaves, which are
brown when the spores rupture the epidermis and are
exposed. It occurs on celery, parsley, and dill, also on
various wild umbelliferous plants, and proves destructive
when present in quantity.

PREVENTIVE MEANS. — Spraying with dilute Bordeaux
mixture checks the spread. Diseased leaves should be
cleared and burned.

Zimmermann, Atlas der Pflanzenkrankheiten, Heft 3
(1886).

Smith, Gard. Chron., 1886, Dec. n, figs.

SUNFLOWER RUST

(Puccinia tanaceti, D. C.)

This rust forms brown pustules on the leaves of the
common sunflower (Helianthus annuus), which are some-
times so abundant that the leaf is destroyed ; and as all
the leaves on a plant are usually attacked, the plant is
prevented from producing fruit.

PREVENTIVE MEANS. — Repeated spraying with Bordeaux
mixture holds the disease in check.

PLUM LEAF RUST

251

The fungus grows on tansy (Tanacetum), and care should
be taken that this host is not allowed to harbour the para-
site in the neighbourhood of sunflowers.

PLUM LEAF RUST

(Puccinia pruni, Pers.)

This rust is very common on the leaves of cultivated
plum-trees, cherry, peach, apricot, and almond, and occurs
wherever these plants are cultivated. The aecidium stage
is absent. The uredo and puccinia stages form small
brown spots on the under surface of the leaves, and are

Fig. 64. — Puccinia pruni. i, portion of a
diseased plum leaf; 2, teleutospore, x 300 ;
3, paraphysis accompanying teleutospores,
X 300 ; 4, uredospore, X 300 ; 5, para-
physis accompanying uredospores, x 300.

so abundant that they almost cover the entire surface.
The uredospores are globose, brown, and minutely warted.
The puccinia-spores or teleutospores consist of two super-
posed globose cells, the uppermost one usually largest, with
a deep constriction where the two join, clear brown, and
warted.

When the leaves are attacked they fall early, consequently
the fruit is poor in quality, and the wood not sufficiently
hardened to resist frost.

PREVENTIVE MEANS. — Spray with dilute Bordeaux

252 PLANT DISEASES

mixture when the leaves are expanding, and again at
intervals if the rust appears. Fallen diseased leaves
should be thoroughly cleaned up and burned.

The fungus is often common on the leaves of the black-
thorn, and care should be taken not to allow this plant to
act as a nurse to the fungus, and thus constitute a centre
of infection.

Prillieux, Malad. des Plantes Agric., vol. i. p. 241.

HOLLYHOCK BUST

(Pucdnia malvacearum^ Mont.)

This rust is a native of Chili, and first appeared as a
pest in Australia, soon afterwards entering Europe through
France, and at the present day is to be met with wherever
the hollyhock is cultivated, and in addition having victim-
ised the wild mallows and allied plants during its distri-
bution. This disease, at the time of its first appearance,
rendered almost impossible the successful cultivation of
the hollyhock; but with the progress made during recent
years in the methods of arresting plant diseases, it can
now be cultivated with success.

The teleutospore phase is the only one formed, and
this appears on the leaves under the form of minute, hard,
pale brown warts ; in many instances the stem, also the
calyx and fruit, are studded with pustules. These teleuto-
spores germinate without a period of rest, the secondary
spores produced continuing the disease. It has been
stated that the teleutospores formed late in the season
act as resting-spores, not germinating until the following
season.

PREVENTIVE MEANS. — Spraying with Bordeaux mixture

PINK RUST 253

is effective. I have ascertained that — without spraying —
when first year plants are diseased, if the fading leaves are
collected, the plants are not diseased the second season,
whereas if the leaves are allowed to decay on the ground
under the plants, they are invariably attacked the second
season ; an observation tending to prove that resting-spores
survive the winter and germinate the following spring. I
have also ascertained that when the carpels are attacked
by the fungus, the seeds produce diseased seedlings, the
cotyledons usually bearing pustules.

PINK RUST

(Puccinia arenariae, Wint.)

During certain seasons this fungus proves very destruc-
tive to pinks and carnations. Teleutospores only are
produced, the small blackish spots being scattered or
arranged in circles on the under surface of the leaves and
the stem. The spores germinate quickly when mature,
hence the disease spreads rapidly.

PREVENTIVE MEANS. — Dilute Bordeaux mixture has
proved effective. I have also seen the disease checked by
sponging with a rose-red solution of potassium perman-
ganate. The fungus is very common on many wild
Caryophyllaceous plants, as chickweed, stitchwort, lychnis,
spurrey, etc.; therefore all such should be kept aloof from
cultivated plants.

HAWTHORN CLUSTER-CUPS

(Gymnosporangium clavariaeforme^ Jacq.)

This destructive parasite is a typical representative of
the group of fungi called Uredineae, the members of which

254 PLANT DISEASES

not only present a very dissimilar appearance, but also
grow as parasites on different plants at different periods
during the completion of their life-cycle. The fungus
under consideration causes spindle-shaped swellings on the
branches oijuniperus communis, and during the months of
April and May numerous flattened, gelatinous masses of
a pale orange colour, and about half an inch in length,
ooze out of these swollen places. The gelatinous out-
growths consist of myriads of reproductive bodies called
teleutospores, imbedded in mucilage. When the teleuto-
spores are mature, they commence to germinate at once,
without falling away.

Each spore produces two long, slender branches or
germ-tubes, each of which bears two or three very minute
secondary spores near its tip. The mycelium of the fungus
is perennial in the juniper branches ; consequently, when a
branch is once infected, a crop of spores is produced each
spring, the diseased patch becoming larger each succeed-
ing year, as the mycelium spreads in the branch. This is
as far as the development of the fungus proceeds on the
juniper. The minute secondary spores, when mature, are
scattered by wind, insects, etc., and those that happen to
alight on the damp surface of a living leaf, young shoot,
or fruit of the hawthorn, or on the leaves of the pear or
the whitebeam, germinate at once, the germ-tube enters
the tissue of the living leaf, and in about three weeks' time
from the period of inoculation produces the second form
of fruit of the fungus, known as the aecidium stage, which
bursts through the tissue of the leaf under the form of
clusters of minute, horn-shaped bodies. These bodies are
hollow, open, and slightly fringed at the tip, and are filled
with minute round bodies capable of germination, called
aecidiospores. Finally, the aecidiospores only germinate

HAWTHORN CLUSTER-CUPS

255

and form a mycelium on branches of juniper, where they
give origin to the first or teleutospore stage of the fungus.

Fig. 65. — Gymnosporangium clavariaefonne. i, teleutospore
stage on branch of juniper ; 2, teleutospores, x 300 ; 3, teleuto-
spores germinating and producing secondary spores a a, x 300;
4, aecidium stage on pear leaf; 5, aecidium stage on branch,
leaves, and fruit of hawthorn ; 6, aecidiospore germinating, x 300.

The aecidium stage of the fungus is often very injurious to
nursery stock, frequently nearly every leaf on the tree being

256 PLANT DISEASES

attacked, the consequence being that the leaves fall quite
early in the season, and the new growth is small in
quantity and imperfectly matured. In the case of full-
grown pear trees, the loss of the leaves early in the
season prevents the formation of a good supply of reserve
material, and consequently a poor crop of fruit the follow-
ing season.

PREVENTIVE MEASURES. — Spraying with fungicides is
of no practical use. The one important point to clearly
understand is the fact that the fungus produces two different
kinds of fruit on different host-plants. The plum tree,
hawthorn, or whitebeam can only be infected by spores
from the stage growing on juniper ; whereas the juniper
can only be infected by aecidiospores formed on one of
the host-plants enumerated. Abolish one of the host-
plants and the mischief ends. Infection has been known
to take place when the two host-plants were half a mile
apart, the spores being carried by the wind. When it is
desirable to retain both trees concerned, then spare no
trouble in discovering the juniper producing the teleuto-
spores, the gelatinous orange masses being quite con-
spicuous in the spring. The most certain method is to
completely remove the infected branches, if this can be
done without disfiguring the tree, as the mycelium of the
fungus is perennial and extends far into the wood, and is
with difficulty destroyed. If it is not desirable to cut out
the diseased juniper branches, remove the bark from the
diseased portion, wash with a strong solution of sulphate
of copper or corrosive sublimate, and afterwards cover the
wound with grafting wax, or paint over with tar. Even
after this treatment a strict watch should be kept on the
branches each spring, otherwise the mycelium present in

PEAR LEAF CLUSTER-CUPS 257

the branch might extend and produce fruit beyond the
portion treated.

The preventive treatment for arresting the ravages of the
species of Gymnosporangium described hereafter is identical
with that given above, some species of juniper being in
every instance one of the two host-plants upon which the
fungus lives and produces its teleutospores.

Plowright, Brit. Ured. and Ustilag., p. 233.

PEAR LEAF CLUSTER-CUPS

(Gymnosporangium sabinae, Winter.)

The teleutospore condition of this fungus grows onfuni-
perus communis,J. oxycedrus,J. virginiana, andy. phoenicea.
The gelatinous masses of spores are formed in the spring,
and are flattened and about half an inch in length, blackish
at first, then reddish-brown. So far as at present known,
the aecidium stage grows only on living pear leaves. The
aecidiospores in turn germinate on young leaves of the
juniper, from whence the mycelium passes into the branch,
where it forms a perennial mycelium, from which a crop of
teleutospores is produced every spring.

Plowright, Brit. Ured. and Ustilag., p. 230.
Prillieux, Malad. des Plantes Agric., vol. i. p. 258.
Fischer, Zeitschr.f. Pflanzenkr., vol. i. pp. 193 and 283.

MEDLAR CLUSTER-CUPS

(Gymnosporangium confusum, Plowr.)

This fungus closely resembles in general appearance and
structure Gymnosporangium sabinae, but differs in its life-
history. The secondary spores will not germinate and

R

258 PLANT DISEASES

produce the aecidium condition on pear leaves, but do so
readily on leaves of the medlar, quince, and hawthorn.
The aecidia, or cluster-cups, are cylindrical and soon split
into shreds; they appear on roundish, thickened, orange
spots, which are often bounded by a reddish or purple
line.

Plo wright, Brit. Ured. and Ustilag., p. 232.

Fischer, Zeitschr.f. Pflanzenkr.^ vol. i. pp. 193 and 283.

MOUNTAIN ASH CLUSTER-CUPS

( Gymnosporangium juniperimim. Winter.)

This is the fourth species having its teleutospore stage
parasitic on Juniperus communis and J. nanus. It is
recognised by the subglobose shape of the soft, gelatinous
spore- masses formed in spring, which are dark brown at
first, changing to orange at maturity. The aecidium stage
grows on living leaves of the mountain ash, and is also said
to have been found on apple leaves. The aecidia are
cylindrical and curved, soon becoming torn into shreds
at the tip. They occur in small clusters on orange-red,
roundish spots.

Plo wright, Brit. Ured. and Ustilag.^ p. 235.

RASPBERRY RUST
(Phragmidium rubi-idaei. Winter.)

This fungus produces its three forms of fruit on the same
host-plant. The aecidium stage is the first to appear, and
may be found in June under the form of small yellow or
greenish-yellow pustules, usually arranged in circles on the

RASPBERRY RUST

259

upper surface of the leaves, less frequently forming elongated
patches on the leaf stalks or stems. Next follows the
uredo stage, which differs but little from the aecidium as
seen with the naked eye : the pustules are small, pale orange,

Fig. 66. — Phragmidium rubi-idaei. i, under surface cf a
raspberry leaflet showing pustules of teleutospores ; 2, teleuto-
spore, x 350 ; 3, section through an aecidium ; a, chains of
warted spores ; b, b, large club-shaped sterile cells forming
the covering of the aecidium, x 300 ; 4, uredospores, x 300.

and scattered, not arranged in circles. Later in the season,
the numerous small black clusters of teleutospores are
produced on the under surface of the leaves.

The teleutospores are very beautiful objects seen under
the microscope, each spore consisting of a single row of

260 PLANT DISEASES

seven to ten cells, dark brown, and minutely warted : stalk
long, colourless, swollen near the free end.

PREVENTIVE MEANS. — Spraying with potassium sulphide
solution checks the extension of the rust. If Bordeaux
mixture is used it should be very much diluted, otherwise
the foliage will be injured. If the disease has run its
course, the fallen leaves should be gathered and burned to
prevent a recurrence of the disease.

Prillieux, Malad. des Plantes Agric., vol. i. p. 251.

ROSE RUST

(Phragmidium subcorticatum, Winter.)

A troublesome pest to cultivators of roses, attacking
more especially hardy hybrid varieties. All three forms of
the fungus are produced on the same host. The aecidia
appear in late spring on the leaves and young shoots, form-
ing powdery, orange patches, and often cause distortion of
the shoots. About midsummer the patches become deeper
in colour, owing to the formation of uredospores. Finally
the teleutospores or resting-spores are produced as minute
black dots on the under surface of the leaves.

PREVENTIVE MEANS. — The appearance of the disease in
spring depends entirely on the presence of teleutospores in
the neighbourhood ; it is therefore necessary to collect and
burn all fallen leaves in the autumn. Plants that have been
attacked the previous season should be thoroughly drenched
with a solution of sulphate of copper in water — 2 ounces
in 3 gallons — in early spring before the buds expand. The
soil round the plants may also be sprayed with the same
solution. Dilute Bordeaux mixture, or ammoniated car-

ROSE RUST

261

bonate of copper solution checks the aecidium and uredo
stages.

Fig. 67. — Phragmidium subcorticatum. i, rose branch
and leaves infected with aecidium stage of disease; 2, leaf
with clusters of teleutospores ; 3, teleutospores, x 300 ;
4, uredospores, x 300.

The fungus also grows on wild roses, and these may
become a source of infection unless precautions are taken.

PINE CLUSTER-CUPS

(Coleosporium senecionis^ Fries.
= Peridermium pini, Wallr.)

One of the heteroecious parasites, the uredo and teleuto-
spore stages forming orange patches on the under surface

262 PLANT DISEASES

of living leaves of groundsel (Senedo vulgaris\ ragwort
(Senedo jacobed), and various other species of Senedo. The
aecidia are of two forms, one cylindrical and slender, formed
on the leaves ; the other much larger and inflated, growing
in crevices of the bark of Pinus siivestris, P. maritima^
P. insignif^ and P. strobus.

PREVENTIVE MEANS. — The injury done is slight, mostly
amounting to a discoloration of the leaves, which, however,
do not fall before the normal time. The removal of species
of Senedo from the neighbourhood arrests the disease.

RHODODENDRON RUST

(Chrysomyxa rhododendri^ De Bary.)

This fungus is heteroecious, the uredo and teleutospore
stages occurring as small pustules on the leaves of species
of Rhododendron, R. hirsutum, and others ; whereas the
aecidium stage grows on the young shoots and leaves of
the spruce. Yellow spots appear on the spruce leaves,
and about August the spermogonia of the fungus appears
on these spots ; at a later period numerous peridia are
produced, and contain such a quantity of spores that when
a diseased tree is shaken the air is filled with a dense
cloud of spores. Diseased leaves die and fall the same
season.

In the present genus the teleutospores consist of a row
of superposed cells. Not a dangerous parasite. The
removal of either of the hosts from the vicinity of each
other checks the disease.

De Bary, Bot. Ztg., 1879.

Hartig and Somerville, Diseases of Trees > p. 177.

PINE CONE FUNGUS 263

Chrysomyxa abietis, Unger. — The teleutospore condition
is alone known, forming pale yellow spots on spruce leaves.
The formation of teleutospore pustules commences during
the year of infection, reaches a certain stage of develop-
ment, and passes into a resting condition until the following
season, when the development is completed, the teleuto-
spores germinating in situ during the month of May,
when the secondary spores produced are conveyed to
young larch leaves, which become infected. Hartig states
that as a rule little injury is caused by the parasite.

PINE CONE FUNGUS

(Ascidium strobilinum, Reess.)

The aecidia are formed on the inner surface of the
carpeilary scales or bracts of cones of the Norway spruce
(Abies excelsa) ; a few aecidia also sometimes develop on
the outer surface of the scales. The mycelium of the
fungus destroys the inflorescence. The aecidia are sub-
globose, or often angular from lateral pressure when
crowded, brown, and opening by an irregular crack.

Hartig states that the diseased fallen cones can be
readily distinguished by opening even in damp weather,
under which condition sound cones remain closed.

Reess, Die Rostpilzformen der Deutschen Coniferen, p. 100.

Aecidium pseudo - columnare^ Kiihn. — The elongated
aecidia grow in two rows on the under surface of the
leaves of Abies pectinata and other species of Abies.

Aecidium magelhaenicum, Berk. — Grows on species of
Berberis. The perennial mycelium distorts the buds of
the host, and causes the formation of ' witches' brooms.'

264 PLANT DISEASES

Aeddium esciilentum, Barcl. — The young shoots of Acacia
eburnea are, in India, distorted and rendered succulent
by the action of this fungus, and such are used as food.

Aeddium ornamentale, Kalchbr. — This aecidium some-
times appears in enormous numbers on branches and
spines of Acacia horrida, at the Cape of Good Hope. The
entire structure and general appearance is completely
altered, the branches formin fantastic curves.

Peridermium harknessi, ^QQ^ — P.filamentosum, Peck.
— The following account accompanied specimens of this
fungus, sent to Kew by Dr. Harkness, from Sacramente,
California : —

* Fungus found growing upon Pinus ponderosa, Dougl.,
up the Sierra Nevada mountains. It attacks the young
tree trunks, and arrests further growth.'

In all the specimens I have had an opportunity of
examining, the fungus has first attacked the stem when
two or three years of age, and in one instance had con-
tinued to grow year by year until the tree was thirteen
years of age, when the specimen had been collected.
During this period of growth, the fungus had caused the
stem at the point of attack to assume a barrel shape, four
inches long, and three inches in diameter. The stem just
below the swelling was one and a half inches across.

The fungus also attacks the following North American
trees : Pinus insignis, Dougl., P. sabiniana, Dougl.,
P. contorta, Dougl.

Peridermium pint, Wallr. — A well-known parasite,
attacking various pines in Europe and the United States.
The mycelium is perennial in the bark, bast, and wood,
and continues to extend year by year. As a rule the
cambium is not destroyed all round the branch at one

PINE CONE FUNGUS

265

point, therefore it continues to grow and yields very
excentric sections, owing to growth being checked by

r

Fig. 68. — Peridermium harkncssi. i, young stem of Pinus
ponderosa, three years old, showing the Peridermium, two-thirds
nat. size ; 2, appearance of a stem eight years old, attacked by the
fungus, the swollen portion being thickly studded with aecidia,
two-thirds nat. size; 3, section through No. 2, the shaded portion
indicates the darkened portion of wood containing mycelium of
the fungus, two-thirds nat. size.

destruction of the cambium on different sides at different
levels. Cells attacked by haustoria lose their contents

266 PLANT DISEASES

and afterwards secrete turpentine in considerable quantity,
which escapes through cracks in the bark. As the disease
encroaches on the wood, the upward passage of water is
checked, and the upper branches die, and are known as
' resin top ' or * resin leader.'

The aecidia appear in late spring, bursting through the
outer dead cortex as irregularly shaped, pale yellow sacs,
which open by an irregular fissure, and liberate the powdery
spores.

Hartig considers that the trunk cannot be infected after
the age of twenty-five years. How inoculation is effected
is not known, neither is the teleutospore form of the
fungus ; consequently the only remedial measure that
can be suggested is the removal of diseased trees.

Hartig, Wichtige Krankh. d. Waldbaumen.

Tubeuf and Smith, Diseases of Plants (Engl. ed.),
p. 411, figs.

Peridermium coruscans, Fr. — This fungus is common on
spruces in Northern Europe, and I have seen it on Abies
pinsapo in England. The whole of the leaves on a young
shoot are attacked, becoming shorter and succulent, and
such branches are eaten in Sweden.

The peridia usually occupy the whole length of the
leaf, rupturing irregularly and exposing the bright yellow,
powdery spores.

Peridermium conorum, Thum.=Aecidium conorum-piceae,
Reess. — The aecidia are large, appearing on the outer
surface of cone bracts of the spruce, few in number (but
not constantly two).

Peridermium elatinum, Wallr. — This species grows on
silver firs, forming cankered swellings on the trunk and

PINE CONE FUNGUS 267

branches. From these swollen spots abnormal branches,
'witches' brooms,' often spring, and are readily recognised
at a distance by growing quite erect, and in the much
smaller yellowish leaves which fall off about the end of
August, the ' witches' broom ' being deciduous.

Aecidia are only formed on the ' witches' broom ' leaves,
and not on the swollen portions of the branch, as in other
species.

The bark is ruptured and thrown off at the cankered
swellings, which consequently often serve as a starting-
point for wound-parasites, especially Polyporus hartigii
and Flammula adiposa.

Hartig and Somerville, Diseases of Trees (Engl. ed.),
p. 17, figs.

Peridermium cerebrum, Peck. — Forms barrel - shaped
swellings on the trunk of Pinus ponderosus^ Dougl., in
America.

Peridermium giganteum, Mayr. — Also forms barrel-
shaped swellings on the trunk of Pinus densiflora^ Sieb.
and Zacc., and P. thunbergii, Parl., in Japan.

Peridermium thomsoni, ^$eik.=Aecidium thomsoni, Berk.,
Gard. Chron., 1852, p. 627, with fig. — Forms large,
elongated aecidia on the leaves of Picea morunda, Link.,
in Sikkim.

Peridermium orientale, Cooke. — Also an Indian species
from the neighbourhood of Simla, growing on leaves of
Pinus longifolia and P. excelsa. The American forms
referred to this species are distinct.

Several other species of Peridermium are parasitic on
the bark or leaves of conifers.

268 PLANT DISEASES

VINE LEAF RUST

(Urcdo vitis, Thumen.
= Uredo vialae, Lagerh.)

This fungus forms small, yellowish, powdery pustules
on cultivated vine leaves, and has been recorded from
the United States and some of the West Indian Islands.

PREVENTIVE MEANS. — The parasite has hitherto occurred
in small quantity, and little or no injury done. Spraying
with a fungicide would probably check its spread, if inclined
to be troublesome.

Lagerheim, Compt. Rend., 1890, p. 728.
Massee, Greviltea, vol. xxi. p. 119 (1893),

CANNA DISEASE

(Uredo cannae, Winter.)

A destructive pest to cultivated cannas in the West
Indies and other parts of the New World, but has not yet
been recorded as doing damage in Europe.

The fungus forms numerous small, orange-coloured
spots on the leaves, which become discoloured and die
in consequence. The summer spores enable the disease
to spread rapidly when once present. Destroying dis-
eased leaves is to be recommended, also spraying with
a fungicide.

SPHAEROPSIDIACEAE

AUSTRALIAN 'SHOT-HOLE FUNGUS '

(Phyllosticta prunicola, Sacc.)

This fungus attacks living leaves of apple, pear, plum,
cherry, apricot, etc. Small brownish spots first appear on

SHOT-HOLE FUNGUS 269

the upper surface of the leaves, which become dry and
brittle, and eventually drop out, giving to the leaf the
appearance of having been riddled with small shot. Tiny
perithecia are produced on the diseased portions. It has
been suggested that the present fungus is a stage of
Leptosphaeria pomona, Sacc,

* '•• ^-^fc

Fig. 69. — Phyllosticta prunicola. I, apple leaves show-
ing the holes formed by the falling away of portions of the
tissue killed by the fungus ; 2, section through a peri-
thecium imbedded in the substance of the leaf, x 18 ; 3,
spores, X3oo.

PREVENTIVE MEANS. — Not very destructive, unless
especially numerous on the leaves, when spraying with
dilute Bordeaux mixture is recommended.

Superficially resembles the 'shot-hole fungus' — Cerco-
spora drcumscissa, — but the fruit is very different.

2;o PLANT DISEASES

CELERY LEAF SPOT

(Phyllosticta apii, Hals.)

Dr, Halsted discovered this disease on celery in the
United States. It differs from Cercospora apii in the spots
on the leaf being dull brown, never pale coloured.

It is described and figured in the N. Jersey Agric. Expt.
Station Report, 1891, p. 253.

Septoria petroselini, Desm., Van Apii, B. and C. — Causes
celery leaves to become brown and studded with small
black dots over the entire surface.

CARROT DISEASE
(Phoma sanguinolentci) Rostr.)

Forming greyish-brown, sunken, cankerlike spots on the
root ; the mycelium during subsequent growth extends into
the stem, where depressed areas are formed which prevent
the umbel from being fully developed, hence no seed is
produced. Numerous minute, dark-coloured perithecia
are present on the diseased patches, the conidia escaping
in long, flesh-red or blood-red strings or tendrils • a char-
acter by which this fungus can be readily distinguished.

PREVENTIVE MEANS. — It is useless planting diseased
roots with the object of procuring seed, as the bloom
is always destroyed. Great care should be exercised in
storing not to include diseased carrots, otherwise the pest
spreads by contact.

CARROT DISEASE

271

Rostrup, Zeitschrift fur Pflanzenkrankh., 1894, p. 195,
pi. iv.

Fig. jQ.—Phoma sangninolenta. i, a diseased
carrot root ; 2, a diseased carrot stem ; 3, portion of
a disease spot, showing perithecia with the conidia
escaping in the form of a mucilaginous tendril,
slightly mag. ; 4, section of a perithecium with the
conidia oozing out in a tendril, highly mag. —
(Zeitschr. fur Pflanzenkr.)

SQUIRT BERRY

(Phoma tuberculatci) M'Alp.)

An Australian grape disease, described by Professor
M'Alpine of the Victoria Department of Agriculture.

272 PLANT DISEASES

The fruit is the part attacked, and when gently pressed
between finger and thumb readily squirts out its contents,
hence the popular name adopted. Berries attacked show
at first a circular patch from ashy-grey to slaty-blue in
colour, dotted and speckled with very numerous gregarious
and confluent tubercles or pustules, for a long time covered
by epidermis. The affected surface usually occupies about
a third of the grape, sometimes almost the whole, and is
somewhat rough in appearance. Towards the end of the
season the berries dry partially, but are always pliable.

The stroma of the fungus is more or less columnar, and
bears the perithecia on its surface. Conidia, oblong or
oval, minute. Various other forms of vegetative bodies,
supposed by the author to be reproductive in function, are
produced on the stroma.

No experiments relating to preventive means have been
tried.

M'Alpine, Add. to Fungi on the Vine in Australia, p.
23, pi. iv.

Phoma solani, Halsted. — Dr. Halsted has described and
illustrated, in the N. Jersey Agric. Expt. Station Report,
1891, a 'damping off' of seedling egg-plants caused by a
Phoma. The disease attacks the seedlings at the base of
the stem, the fruit of the fungus appearing as exceedingly
minute black dots on the diseased parts.

Phoma hennebergii) Kuhn. — Often proves very destructive
to the wheat crop, attacking the glumes and causing the
ears to shrivel. The fungus sometimes also appears on the
leaves.

Frank, Zeitsch. fur Pflanzenkr., vol. iii. 1893, p. 28.

ONION SCAB 273

ONION SCAB

( Vcrmicularia rircinans. Berk.)

This is an erratic parasite, being very abundant during
certain seasons, and entirely absent at others. As a rule
but little injury is done to the bulbs, which are the only
part attacked, so long as they remain in the ground ; never-
theless the unsightly black blotches on the outermost
scales considerably reduce their market value.

The fungus usually appears when the bulbs are nearly
full-grown, under the form of scattered black patches,
formed of minute black, velvety tufts, arranged in con-
centric circles, or irregular, wavy lines. If one of these
mature velvety tufts is examined under the microscope, it
is found to consist of myriads of erect threads, each bear-
ing a long, slender, slightly curved, colourless spore at its
tip, and in addition the tuft is thickly studded with long,
black, projecting spines, which give to it the velvety
appearance when seen through a pocket-lens.

PREVENTIVE MEANS. — Bulbs showing the least signs of
the disease should not be mixed with healthy ones, and the
bulbs should be thoroughly dry before storing, otherwise
the disease will spread quickly ; as, notwithstanding great
care, a few very slightly tainted bulbs are liable to be
passed ; and if there is the least indication of sweating, the
resulting moisture and heat greatly facilitate the growth
of the fungus, which often spreads with startling rapidity.
Diseased bulbs should not be allowed to decay on the
ground, but should be carefully collected and burned,
otherwise the spores remain in the soil for some time in a
condition ready for germinating • and it must be borne in
mind it is only necessary that a single onion should be

S

274

PLANT DISEASES

inoculated, to secure for the fungus a foothold from which
it can attack neighbouring plants, and, in the course of the
season, victimise most or all the plants in the neighbour-
hood.

Fig. 71. — Vermicularia circinans. i, onion
attacked by Vermicularia ; 2, one of the black
tufts of the fungus, x 50 ; 3, portion of a tuft show-
ing the curved conidia borne at the tips of slender
threads or conidiophores, also the long black
spines, X2so.

Berkeley, Gard. Chron., 1851, p. 595, figs.
Stoneman, Bot. Gaz., 1898, p. 98. fig. 16.

GIRDLING OF SILVER FIR 275

GIRDLING OF SILVER FIR

(Fusicoccum abietinum^ Sacc.
,) Hartig.)

Hartig called attention to a disease of the silver fir,
which, although previously undescribed, is very common in
the Bavarian Forest, Black Forest, etc. The disease is
characterised by usually killing the bark all the way round
both small and large branches. If the bark is only killed
on one side of the branch, it is shed, and a callus forms
along the uninjured margin,

Numerous minute black stromata containing cavities
bearing small fusiform conidia are developed in the dead
cortex, and rupturing the tissues appear on its surface.

Hartig and Somerville, Diseases of 'Trees ', p. 138, figs.
Prillieux, Malad. des Plantes Agric., vol. i. p. 285, figs.
Mer., Journ. de Bot., 1893, p. 364.

PEA SPOT

(Ascochyta pisi, Libert.)

Sometimes injurious to cultivated peas (Pisum sativuni),
haricot beans (Phaseolus vulgaris), and species of Vicia^
and Cercis. Pale spots are formed on the pods which
cause them to become stunted and deformed. The leaves
and stem are also attacked.

PREVENTIVE MEANS. — None recorded. Probably spray-

276 PLANT DISEASES

ing with Bordeaux mixture would prove beneficial.
Diseased portions should be burned.

Fig. 72. — Ascochyta pisi. i, pod and leaflet of garden
pea diseased ; 2, section through two conceptacles of the
fungus, slightly mag. ; 3, conidia, x 300.

LEAF SCALD

(Entomosporium maculatum. Lev.)

A very destructive fungus to pear, apple, peach, quince,
cherry, and other rosaceous fruit-trees. Diseased leaves
fall early in the year, and as all the leaves on a tree are
usually attacked, defoliation results; not unfrequently a
second growth of leaves takes place, and these suffer in the
same way, consequently the tree is much weakened, and in
the case of nursery stock the trees are frequently killed
outright, or are so enfeebled that grafting becomes a
difficult matter. In bad cases the fungus also attacks the

LEAF SCALD

277

young shoots, and has been considered as causing the
spottiness and cracking of fruit, pears more especially.
Small red spots appear on the upper surface of leaves when
still young ; these increase in size and become brown,
having one or more minute black spots — the fruit of the
fungus — slightly projecting above the general surface. If
the spots are numerous, as is usually the case, and the leaf

Fig. 73. — Entornosporium maculatum. i, quince leaf
diseased ; 2, spores of the fungus, x 300.

young, it becomes altogether brown, shrivels, and falls off.
If the leaf is older, with rigid tissues, it retains its shape,
but falls to the ground. The spores, as shown in the
accompanying figure, have a very characteristic shape. On
the branches the spots are at first reddish and circular,
elongating, becoming slightly sunken with a central elevation,
and blackish in colour ; these often coalesce to form

278 PLANT DISEASES

irregular patches encircling the branch, in which case the
portion above the diseased area dies.

Dr. Sorauer considers that an ascigerous fungus, called
by him Stigmatea mespili, which occurs on the diseased
spots on fallen leaves previously occupied by the
Entomosporium, is really the higher condition of that
fungus; this idea has not, however, as yet been corrobo-
rated by cultures.

PREVENTIVE MEANS. — Spraying with Bordeaux mixture
holds the disease completely in check ; the first spraying
should be applied, using a very dilute solution, as the
leaves are expanding.

Dead leaves should be collected and burned. Diseased
branches should be removed, as it is probable that the disease
first originates as an epidemic in the spring, from spores
produced by the mycelium permanent in the branches.

Leveille, Bull. Soc. Bot. France, vol. iii. p. 31.

Sorauer, Handb. der Pflanzenkrankheiten, vol. i. p. 372,
pi. xvi., figs. 6-9.

Galloway, Rep. Commits. Agric. U.S., 1889, p. 357, pi.
viii., ix.

Entomosporium thumem, Sacc. — Somewhat similar in
appearance to E. maculatum • occurs on living leaves of
species of Crataegus.

MELANCONIACEAE

GRAPE ROT

(Gloeosporium ampelophagum, Sacc.)
This minute fungus is one of the scourges of European
vineyards, where its ravages have repeatedly proved most
disastrous. In Britain, however, it is not common, and

GRAPE ROT

279

with the exercise of ordinary intelligence and care can be
readily stamped out when it occurs, as but comparatively
few vines have to be dealt with in any one locality. Since

Fig. 74. — Gloeosporium ampelophagnm. i, appearance
of the disease on the leaves, stem, and tendrils of the vine ;
2, diseased grapes ; 3, section through a fruit pustule formed
on a young grape, x 300 ; 4, conidia, X4oo.

1 88 1 it has also caused considerable anxiety and loss to
American viticulturalists, having in all probability been
imported to that country from Europe.

280 PLANT DISEASES

The young shoots, leaves, and fruit are attacked, the
disease often appearing in the spring and continuing till
the cessation of active growth of the host. On the leaves
the fungus forms small, irregularly scattered, greyish spots,
bordered by a dark line ; sometimes the central portion of
the spots becomes dry, brittle, and eventually falls out, form-
ing holes in the leaf. On the young shoots, tendrils, and
leaf-stalks the spots at first resemble those on the leaves,
but soon become elongated ; the central portion sinks
owing to the decay of the tissues, the bark and under-
lying wood, sometimes down to the pith, being destroyed
by the fungus. The spots on the fruit usually retain a
circular outline and become larger than those on the
leaves, and not unfrequently run into each other, forming
irregular blotches, and have a bright red ring inside the
blackish border, hence the American name, ' Bird's-eye rot.1

The growth of diseased fruit is arrested, and finally it
shrinks and dries up, still remaining hanging. As a rule
all the grapes in a cluster become diseased, one infecting
another. The grey central portion of the patch becomes
studded with black points when mature, which when
examined under the microscope are seen to consist of
dense tufts of upright, slender branches or conidiophores,
each bearing a minute, colourless conidium at its tip.

These conidia germinate quickly in water, and are
washed by rain and dew, or carried by insects or birds
from one tree to another, and thus spread the disease.

PREVENTIVE MEANS. — This disease is undoubtedly very
difficult to combat successfully. Dredging with flowers of
sulphur may be practised on the shoots and leaves, repeat-
ing at intervals of ten days if the disease continues to
spread. A small quantity of quicklime should be mixed

APPLE ROT 281

with the sulphur on the second application, and the
quantity of lime should be increased on each successive
application, until the proportions of lime and sulphur are
nearly equal, always keeping just a little more sulphur than
lime. It has been found of service to thoroughly wet the
branches with a solution of sulphate of iron when the vine
is resting.

The use of rich stable manure is stated to make vines
more susceptible to this disease.

Diseased leaves and shoots should be collected and
burned, and diseased fruit should also be removed as
speedily as possible.

Viala, Malad. de la Vigne, ed. iii. p. 204, pi. v. and figs.
Arcangeli, Nuovo Giorn. Bot. Ital. vol. ix. p. 74, pi. ii.
Massee, Card. Chron., Feb. 2, 1895, fig8-

APPLE ROT

( Gloeosporium fructigenum^ Berk. )

This disease, first investigated by Berkeley, is very
destructive to ripe apples, causing the too familiar brown,
sunken patches, the diseased portion having a very bitter
taste.

The disease usually first appears as minute spots when
the fruit is about half-grown, and continues to enlarge,
retaining a rounded form, but frequently increasing in
size so much that several originally distinct spots blend
together, and form a large irregular patch, and not
unfrequently the entire surface is eventually covered.
Black, slightly raised, minute points, often arranged in
irregular circles, form on the diseased parts; these represent
the fruit of the fungus, consisting of numerous closely

282 PLANT DISEASES

packed conidiophores, each bearing a single conidium at
its tip. Eventually the epidermis of the apple is split at
the apex of each pustule, and the spores escape in the
form of a slender tendril, held together by mucus. In the
case of stored fruit, if these spores come in contact with

3,

- 75- — Gloeosporium fruchgenum, i, appearance
of the disease on an apple ; 2, showing the apex of one
of the black pustules or fruit of the fungus ; the spores
are escaping stuck together into a thread or tendril,
through a rupture in the epidermis of the apple, x 50 ;
3, section through one of the pustules showing the
conidiophores bearing conidia at their tip, x 50 ; 4, three
conidiophores, each bearing a conidium at its tip, x 300.

healthy apples, the disease is communicated, and in a very
short time the disease spreads through the entire stock.
A second and higher form of fruit is suspected, but the
genetic connection is not yet proved.

It has been proved in the United States that this fungus
also attacks grapes, pears, peaches, etc.

APPLE ROT 283

PREVENTIVE MEANS. — If apples are large when attacked,
they usually soon fall ; such should not be allowed to
remain on the ground, as the fungus present continues to
form spores if the winter is mild, and proves a source of
infection the following season.

On the other hand, if young fruit becomes diseased, it
usually remains hanging on the tree ; such mummified
fruit should also be removed and burned. Do not throw
diseased fruit into the pigsty or on the manure-heap, but
burn it.

When storing, all fruit exhibiting the slightest trace of
disease should be picked out.

The following quotation shows how the Americans treat
this disease : —

' Mr. Curtiss has repeatedly lost all of certain varieties
[of apples] by this fungus, and his orchard offered a good
field for experiment. In order to make the value of the
remedies used perfectly clear, he left some of the trees
unsprayed, and in one case he only sprayed half a tree,
leaving the other half unsprayed as a check. The remedies
used were potassium sulphide — one half-ounce to a gallon
of water — and the ammoniacal copper carbonate. The
sprayings were not begun until August the i8th for the
potassium sulphide, and August 2yth for the copper car-
bonate, too late in both cases for the best results, as the
disease had already made considerable progress. But
even under these unfavourable conditions the result was
very marked. The apples that were not diseased at the
time of spraying were perfectly protected, while the un-
sprayed trees dropped all their fruit. On the tree that
was half sprayed the difference between the two sides was
as marked as between the sprayed and unsprayed trees.

284 PLANT DISEASES

If the spraying had been done a month earlier, it is reason-
able to suppose that with proper care in application the
rot could have been almost entirely prevented.

* Where copper remedies are used for black rot or mildew,
it is not unlikely that the grapes are in danger from the
ripe rot [= apple rot], and in cases where no remedies
have been used, two or three sprayings will probably pro-
tect the grapes. For this it will not be necessary to go to
the expense of preparing the Bordeaux mixture, but the
ammoniacal solution, or even the potassium sulphide
solution, will probably be satisfactory.'

Galloway, U.S. Dept. of Agriculture, Bull. No. 8, p. 61 ;
and in Ann. Rep. U.S. Dept. Agric., 1889, p. 412, figs.

Southworth, Journ. My col .^ vol. vi. p. 164.

PLANE LEAF SCORCH

(Gloeosporium nervisequum, Sacc.)

A destructive fungus, causing defoliation of planes in
Europe and the United States. When the leaves are just
full-grown, scattered brown spots appear, often following
the veins ; sometimes the patches become very large,
from the meeting and blending of originally distinct areas
of disease. The mycelium passes from the veins into the
leaf-stalk, when the leaf soon falls before it is dead;
by this means trees are often destitute of leaves at mid-
summer. Minute blackish pustules containing the spores
are formed on the veins on the under surface of the leaf.
At maturity the spores ooze to the surface in a mass, held
together by mucilage, are dispersed by rain, and, being
capable of germinating at once, infect fresh leaves.

Platanus ocridcntalis, L., and P. orientalis, L., suffer
severely, P. occidentalism the American species, being most

PLANE LEAF SCORCH

285

susceptible to the disease, both at home and in Europe.
Platanus raccmosa, Nutt. the sycamore of the United

Fig. 76. — Gloeosporium nervisequiim, Sacc. i, a diseased leaf
of plane, reduced ; 2, spores, x 300.

States, is also attacked. It has also been recorded as
occurring on oak leaves in America.

Prillieux, Malad. des Plantes Agric., vol. ii. p. 320, figs.
Stoneman, Bot. Gaz., vol. xxvi. p. 70, figs.

286 PLANT DISEASES

RASPBERRY SPOT

{Glocosporium venetum, Speg.)

A widespread disease, first appearing on the young
canes under the form of small reddish spots. These con-
tinue to increase in size, and frequently run into each
other, forming irregular blotches, which become grey in
the centre, and bounded by a red margin. The minute
spores ooze out from under the cuticle of the central grey
spots, and are at first held together by a viscid substance,
which becomes dissolved by moisture; the spores are
diffused, germinate at once, and spread the disease.
Similar diseased spots are also produced on the leaves.

PREVENTIVE MEANS. — The quickly germinating summer-
spore form is the only known mode of reproduction, and
it is supposed that the mycelium is perennial in the tissues.
Young canes are not killed by the disease the first season,
but succumb the second season, the fruit remaining small
and shrivelled.

All diseased leaves and canes should be removed, and
the canes should be sprayed with a solution of sulphate of
iron — two pounds dissolved in five gallons of water — during
the winter before the leaf-buds expand. After the expan-
sion of the foliage, dilute Bordeaux mixture has proved
beneficial.

CURRANT LEAF SPOT

(Gloeosporium ribis, Mont.)

The leaves of red and black currants and gooseberries
are often attacked by this fungus, and when this occurs to

CURRANT LEAF SPOT 287

a serious extent the leaves fall early, and the fruit does
not ripen properly, if at all. Further, such trees are unable
to accumulate the necessary amount of reserve material,
and consequently do not produce a good crop of fruit the
following season.

The disease usually appears when the leaves are just
full-grown, appearing as minute blackish spots, chiefly on
the upper surface. These spots are caused by dense tufts
of mycelium in the tissues of the leaf, which increase in size
and eventually rupture the epidermis, the minute spores
escaping in the form of a tendril, being stuck together by
mucus. When on the surface, these strings of spores are
washed apart by dew or rain, and find their way to other
leaves, where they germinate, and thus spread the disease.

PREVENTIVE MEANS. — Very dilute Bordeaux mixture,
or potassium sulphide solution, if applied sufficiently early,
checks the disease.

Dudley, Cornell Expt. Station, U.S., No. 15.

BANANA ANTHRACNOSE

(Gloeosporium musarum, Cke. and Massee.)

Forming blackish spots which gradually spread over the
entire surface of the fruit, causing rotting to take place.
The black spots are suffused with a roseate tint when the
spores are extruded.

First described as occurring on ripe bananas at Bris-
bane ; afterwards met with in the United States on the
same host.

Diseased fruit should be removed as soon as the small

288 PLANT DISEASES

black spots are noticed, to prevent the spread of the
fungus.

Stoneman, Bot. Gaz., vol. xxvi. p. 69, fig.

Gloeosporium rhododendri, Briosi and Cavara. — This
fungus forms large yellowish blotches on the leaves. The
minute black pustules containing the spores are arranged
in irregular concentric circles on the bleached spots.

Briosi e Cavara, Fung. Parassiti delle Piante Coltiv. od
Utili, No. 198, fig.

Gloeosporium bicolor, M'Alp. — Forming wax-yellow,
then brown pustules on ripe grapes in Australia. Differs
from allies in the conidia being colourless, even in the
mass. No bitter taste is imparted to the fruit attacked.

M 'Alpine, Add. to Fungi on the Vine in Australia, p. 38.

ANTHRACNOSE OF SCAELET RUNNER

(Colletotrichuni lindemuthianum, Briosi and Cavara.)

A disease commonly attacking the pods of scarlet
runners, less frequently those of French beans, sometimes
also present on the stem and leaves.

On the pods the disease appears first as small dark
spots, bounded by a reddish line. These spots continue to
increase in size and often run into each other, forming
irregular blotches, which become sunk below the general
level of the surface. On the stem the patches corrode the
tissues and kill the part above the wound.

ANTHRACNOSE OF SCARLET RUNNER 289

When pods are badly diseased, they are often con-
torted ; the beans are also some-
times attacked.

Professor Halsted states that
this fungus is parasitic on the
living rind of cucumbers, pump-
kins, water-melons, and musk-
melons.

PREVENTIVE MEANS. — Spray
with Bordeaux mixture when
the disease first appears on the
stem or leaves, which will pre-
vent its passing on to the pods.
Badly diseased plants should be
removed. Seed obtained from
plants where the disease has
existed should not be used.
Plants grown in damp situa-
tions are most liable to the
disease.

Voglino, Fungi Dannosi alle
Piante Coltivate, pi. 8.

Halsted, Bull. Torr. Bot., vol.
xx. p. 246, figs.

Beach, N. Y. Expt. St., Bull

Nn yiR fio-s Fig- 77- Colletotrichutn lindc-

*°> u&a> muthianum. i, diseased pod of

MnccP^ Cn<rJ Chrnti Miv n scarlet runner ; 2, portion of fruit-

ee, Lrara. ^nron., Ma> 7, bearingsurfacejShowingthespores

1898, figS. borne singly at the tips of long

sporophores, also two long spines
projecting above the mass of the
spores,

290 PLANT DISEASES

COTTON ANTHRACNOSE

(Colletotrichum gossypii^ South w.)

Either alone, or accompanying the fungus causing ' black
rust' (Cercospora gossypina, Cke.), this fungus does con-
siderable injury to the cotton crop in the southern United
States. On the ' bolls ' or fruit the fungus causes depressed,
blackish spots, which ultimately assume a reddish tint, due
to the formation of spores. The leaves and stem are also
attacked, soon looking as if killed by frost; the stems
blacken, and the plant usually dies.

Atkinson, Journ. Mycol.> vol. vi. No. 4, p. 173, 2 pi.

HOLLYHOCK ANTHRACNOSE

(Colletotrichum althaeae. South w.)

A fungus that has caused considerable trouble in
America to hollyhocks grown in greenhouses, and has
quadrupled their value in New York. Any part of the
plant may be attacked; on the leaves brown spots are
formed, which may increase in size until the whole leaf is
diseased or withered. The spots vary from light yellowish-
brown to black.

PREVENTIVE MEANS. — Spraying with dilute Bordeaux
mixture at intervals, commencing as soon as the leaves
appear, although not effecting all that could be wished,
proved to be the best fungicide experimented with. Dis-
eased plants should be removed at once.

Southworth, Journ. MycoL, vol. vi. No. 2, p. 45, i pi.

SPINACH ANTHRACNOSE 291

SPINACH ANTHEACNOSE

(Colletotrichum spinaceae, Ellis and Hals.)

This disease has proved especially destructive to spinach
in the United States. The spots formed on the leaves are
at first minute, and present a moist appearance. These
gradually increase in size, become grey, dry, and studded
with numerous dark points, often on both surfaces of the
patch. The fruit comes to the surface through the
stomata.

Halsted, N. Jersey Agric. Coll. Expt. Station, Bull. 70,
figs.

CHERRY AND PLUM LEAF BLIGHT

(Cylindrosporium padi, Karsten.)

According to Fairchild, nursery stock of cherries and
plums are often severely attacked, the leaves falling so
early as to render the first year's growth of stocks almost
insignificant. Plum trees suffer more than cherries, as the
leaves fall while yet green, whereas in the latter the leaves
often assume autumnal tints before falling. Great variation
exists as to the susceptibility of different varieties, the
English Morello cherry being especially victimised.

The disease appears under the form of small, round,
purple spots on the leaf, these eventually become brown,
dry up, and drop out, leaving holes in the leaf.

PREVENTIVE MEANS. — Bordeaux mixture arrests the
disease. Spray first when the leaves are expanding, and
again after an interval of three weeks.

Fairchild, Journ. MycoL, vol. vii. p. 249, pi. xxi.-xxix.
(1893).

292 PLANT DISEASES

CHRYSANTHEMUM LEAF BLIGHT

(Cylindrosporium Chrysanthemi, Ellis and Dearn.)

Mr. J. Dearness has described a chrysanthemum leaf
blight which proved destructive to cultivated plants in
Ontario, Canada. Large dark blotches appear on the
leaves, which turn yellow, and shrivel. When attacked
the flower-buds do not expand.

Numerous fruiting pustules are formed on the diseased
patches ; these produce myriads of long, narrowly spindle-
or club-shaped, colourless, septate conidia, which rupture
the epidermis of the host, become diffused, and spread
the disease rapidly.

The diseased leaves hang down and lie close to the
stem.

PREVENTIVE MEANS. — 'The owners sprayed the plants
with all their fungicides, but without any apparent effect
on the disease. Doubtless the best course is to burn the
affected leaves, or destroy the plant as soon as the disease
is observed.'

FIG TREE DISEASE

(Libertella ulcer at a, Mas see.)

This parasite causes the bark to become cankered and
cracked, large patches completely disappearing as the
disease progresses. When a branch is girdled, the portion
above the wound dies, and then produces the fruit of the
fungus in minute cavities in the bark, the very minute
conidia oozing to the surface in the form of fine hairs,
composed of conidia stuck together by a viscid substance,
which is dissolved by wet. The conidia are not capable

PANDANUS DISEASE 293

of inserting a germ-tube into the unbroken surface of the
bark, but gain an entrance through wounds. A knife used
for cutting out a diseased portion was afterwards used for
making a slight incision in the branch of a healthy plant,
and the disease followed.

PREVENTIVE MEANS. — All wounded surfaces should be
coated with tar at once, and care should be exercised in
pruning or trimming not to cut sound branches with a
knife that has been used for cutting out diseased parts,
until it is disinfected.

Massee, Gard. Mag., July 23, 1898, fig.

PANDANUS DISEASE

( Melanconium pandani, LeV.)

The surface of the trunk, aerial roots, and adventitious
branches of cultivated species of Screwpine (Pandanus)
are sometimes attacked by a fungus which forms small
black pustules, bursting through the epidermis, and at
maturity extruding black, subgelatinous tendrils, consisting
of minute conidia held together by a mucilaginous sub-
stance. These pustules are often produced in immense
numbers, and blacken the parts attacked.

An ascigerous form — Nectria pandani, Tul. — frequently
appears on the Melanconium pustules, and the two are
considered as phases of one fungus, but this has not yet
been proved.

PREVENTIVE MEANS. — If the diseased parts are cut out,
and the wounds covered with a fungicide as soon as the
disease is observed, it may be arrested ; if neglected, the
plant invariably dies.

294 PLANT DISEASES

CHEERY LEAF SPOT

(Coryneum beyerinckii, Oud.)

This fungus attacks not only the cherry but also the
peach, apricot, almond, and plum. Not unfrequently in
spring the young leaves show red or rosy spots on the
under surface; such are also often present on the young
shoots. At a later stage the tissue at diseased points be-
comes brown, and dies, and the conidia of the fungus are
produced in minute black spots grouped on the dead
portions, which finally as a rule fall away, leaving the
leaf perforated. The diseased spots on the twigs are
usually elongated. When the fruit is attacked the flesh
dries up to the stone.

Late in the season a second form of fruit — pycnidia —
appears on the diseased patches on the twigs, and on
mummified cherries an ascigerous condition has been de-
tected the following spring. These are supposed to belong
to the Coryneum, but the point has not yet been definitely
settled. The ascigerous condition has received the name
of Ascospora beijerinckii, Vuill. A certain amount of gum-
ming sometimes takes place on branches attacked by the
fungus, but whether caused by the parasite is not known
with certainty ; Vuillemin thinks not.

PREVENTIVE MEANS. — No methods have been recorded,
but probably spraying at the time when the leaf-buds are
expanding would prove beneficial.

Oudemans, Hedw.^ 1883, p. 113.

Vuillemin, Journ, de Bot., vol. ii. p. 255.

Prillieux, Malad. des Planles Agric., vol. ii. p. 337, figs.

GREY BLIGHT OF TEA PLANT

295

'GREY BLIGHT' OF TEA PLANT

(Pestalozzia guepini, Desmaz.)

Said by Dr. Watt to be one of the most destructive and
dangerous of parasitic fungi to which the tea plant is liable.
It occurs in Assam and Cachar, and probably in all the

\

"^

Fig. 78. — Pestalozzia guepini. I, blotches caused
by the fungus on a tea leaf, slightly reduced; 2,
spores of the fungus, x 350.

tea districts of India, also in Ceylon. The disease first
appears as minute, brownish-grey spots on the upper
surface of the leaves. These spots gradually increase in
size and coalesce, forming large, irregular blotches, which
finally become grey and sprinkled with minute black points,
the fruit of the fungus. During the increase in size the

296 PLANT DISEASES

blotches are often bordered by a dark, slightly raised line.
Diseased leaves are not at all blistered or swollen ; in fact,
the grey patches are thinner than the uninjured portion of
the leaf, owing to collapse of the tissues.

Dr. Watt states that the disease commences for the
most part on one side of a bush, very often on the same
side of all the bushes over an affected plot — a circumstance
that may be taken as indicative of the germs having been
wind-conveyed.

In addition to growing on the tea plant, Pestalozzia
guepini also occurs as a parasite on other species of
Camellia and on Rhododendron in India ; in Europe it is
not uncommon on cultivated camellias and rhododen-
drons. In the United States it also occurs on introduced
species of Camellia and Citrus, from whence it possibly
passed on to the native Magnolia, Finally, it is known to
occur on indigenous plants (Niphobolus) in New Zealand,
and on Alphitonia in Queensland.

PREVENTIVE MEANS. — The remarks I offered in the
Kew Bulletin are repeated here. If the diseased leaves
were collected with the amount of care and intelligence
exercised in collecting sound leaves, and burned at once
after being collected, the disease would soon be stamped
out, as the mycelium of the fungus is not perennial in the
tea plant ; consequently infection and a recurrence of the
parasite depends entirely on inoculation by the numerous
conidia or reproductive bodies of the fungus present on
diseased leaves. Remembering the very different kinds of
plants on which the fungus is known to be parasitic, it is
very probable that it also occurs on wild plants growing in
the vicinity of the tea-gardens. If such proves to be the
case, all such plants should be removed if practicable, as

CONIFER SEEDLING DISEASE 297

the conidia of fungi are carried considerable distances by
wind, birds, and insects, and no amount of attention in
the way of removing the parasite from the tea plants would
avail if the supply of conidia requisite for inoculating the
tea plants were formed on other plants growing in the
neighbourhood.

Watt, The Pests and Blights of the Tea Plant,
Massee, Kew Bulletin, 1898, p. 106, figs.

CONIFER SEEDLING DISEASE

(Pestalozzia hartigii, Tubeuf.)

Seedlings of spruce and silver fir are frequently destroyed
in large numbers, due to the injuries caused by this Pesta-
lozzia. In summer young plants lose their colour and die.
On examination it is found that the cortex just above
ground is destroyed, and closer search reveals the presence
of numerous minute masses of fungus mycelium or stromata
bearing those peculiar conidia characteristic of the genus
Pestalozzia.

PREVENTIVE MEANS. — Remove and burn all diseased
seedlings.

Tubeuf, Beitr. zur Kenntniss der Baumkrankheiten, p. 40,
pi. v., 1888.

Hartig and Somerville, Diseases of Trees, p. 136, figs.

MAPLE BLIGHT

(Septogloeum hartigianum, Sacc.)

The year-old branches of maple (Acer campestre),
especially those forming the crown of the tree, are often

298 PLANT DISEASES

destroyed by the pest named above. Two-year-old shoots
are only very rarely infected. In the month of May the
periderm of diseased shoots is ruptured at intervals longi-
tudinally, exposing the conidial layer of the parasite as a
greyish-green cushion, bounded by the upraised periderm.
Young shoots are infected in May and June by the conidia
before the periderm is formed, and such usually perish the
following season.

PREVENTIVE MEANS.: — Hartig states that the disease can
be prevented by removing the diseased shoots from the
crown in the beginning of May.

Hartig and Somerville, Diseases of Trees, p. 141, fig. 80.

HYPHOMYCETACEAE
MUCEDINEAE

(Oospora abietum, Oud.)

Defoliation of various conifers — Abies excelsa, A. pinsapo,
A. nordmanniana, and A. douglasii — results from the injury
done by an inconspicuous fungus called Oospora abietum.
A single row of minute greenish-grey fluffy tufts on each
side of the nerve, and on both surfaces of the leaf, come
to the surface through the stomata; the delicate hyphae
composing these tufts produce minute, colourless, elliptical
conidia, which, being scattered by wind or rain, alight on
other healthy leaves and spread the disease.

PREVENTIVE MEANS. — It is advised that all fallen leaves
should be collected and burned.

Oudemans, Compt. Rend, de VAcad. Roy. d.Sd. des Pays-
Bas, seance de Jan. 1897.

AMERICAN POTATO SCAB 299

AMERICAN POTATO SCAB

(Oospora scabies, Thaxter.)

This troublesome disease, although so generally dis-
tributed, has only quite recently been thoroughly investigated
by an American — Dr. Thaxter. The parasite usually attacks
the tubers while young, forming rough patches on the
surface, known as ' scab.'

When just dug up, a very delicate greyish mould is present
on young diseased patches, which however soon entirely
dries up and disappears. Beet, swede turnips, carrots, and
cabbages also appear to be susceptible to the same disease,
and should not follow a crop of potatoes, as the germs
remain in the soil for some years.

This parasite has nothing in common with potato scab,
as understood in Britain.

PREVENTIVE MEANS. — Professor Bolley recommends the
following treatment : — Immerse potatoes intended for plant-
ing— contained in a sack of open texture — for an hour and
a half in a solution consisting of two and a quarter ounces
of corrosive sublimate (bichloride of mercury) to fifteen
gallons of water, after which they may be cut and planted
as usual after being spread out to dry. First dissolve the
corrosive sublimate in a few gallons of hot water, and place
the solution in a cask or wooden vessel, as the mixture
corrodes metal. The solution is poisonous, and care should
be used.

It has recently been proved by Professor Arthur that
steeping potatoes in a solution of half a pint of formalin in
fifteen gallons of water for two hours is a complete specific.

Thaxter, Ann. Rep. Conn. Agric. Expt. Station, 1890,
p. 84

300 PLANT DISEASES

Bolley, Bull. No. 4 and No. 9, N. Dakota Agric. Expt.
Station,

Arthur, Indiana St., Bull. No. 65, pp. 19-36.

BROWN ROT OP FRUIT

( Monilia fructigena> Pers.)

One of the commonest and most widely distributed of
moulds against which the fruit-grower has to contend. It
attacks apples, plums, cherries, and other kinds of orchard
fruit, and is also common on various wild fruits belonging
to the Order Rosaceae.

In Britain it is most frequently seen on apples, and
although best known to the casual observer on the fruit,
occurs also on the young shoots, leaves, and even the
flowers.

On the leaves, where the fungus usually appears in the
spring, it forms thin, velvety, olive-brown patches, consist-
ing of chains of barrel-shaped spores, originating from the
mycelium present in the tissues of the leaf. At maturity
the spores become free, and are carried by rain, wind,
insects, or birds on to the surface of healthy leaves or young
fruit, where, if conditions are favourable, a new disease-
spot is formed.

On the fruit the first indication of disease is indicated
by the appearance of brownish scattered patches on the
skin. This is followed by the appearance on the surface
of small tufts composed of chains of spores. As the disease
extends, the tufts of spores are usually arranged in irregular
circles round a central starting-point.

BROWN ROT OF FRUIT 301

Fruit attacked by the fungus does not readily rot, but
remains in a mummified condition throughout the winter,
either lying on the ground, or frequently hanging on the
tree. During the winter, the mycelium, which permeates
every portion of diseased fruit, forms numerous minute,
blackish sclerotia. On the return of spring, these sclerotia
bear a crop of spores, which are carried on to the young
leaves, and a recurrence of the disease ensues.

•¥

' ^«^ •^

Fig. 79. — Manilla fnictigena. I, an apple badly diseased ;
a pustule of the fungus, x 50 ; 3, chains of Manilla spores,
200.

2, a

PREVENTIVE MEANS. — The mycelium is not permanent
in any part of the host ; consequently every spring the trees
are perfectly free from disease, and would remain so if not
inoculated by spores derived from the diseased fruit of the
previous season ; hence all diseased fruit should be collected
and burned. Where the disease has already existed, the
trees should be thoroughly drenched, with a solution of
sulphate of iron in early spring before the buds expand ;

302 PLANT DISEASES

and after the buds have expanded, with dilute Bordeaux
mixture at intervals of ten days.

Smith, Gard. Chron., vol. xxiv. p. 51, figs.
Massee, Brit. Fungus- Flora, vol. iv. p. 281.
Smith, Journ, MycoL, vol. v. p. 123.
Arthur, Fourth Ann. Rep. N. York Agric. Expt. Station,
p. 254 (1885).

DEMATIEAE

APPLE SCAB
(Fusidadium dendriticum, Fuckel.)

The most injurious of fungus parasites attacking the
apple, in many instances rendering unsaleable half or more
of the entire crop, in addition to doing permanent injury to
the trees. It was at one time considered that the disease
was confined to the fruit, but it is now well known that the
leaves and young shoots are also attacked ; in fact, as a
rule the fungus first appears on the leaves under the form
of small, roundish, dark spots, mostly on the upper surface.
These spots soon increase in size, and run into each other,
forming large, irregularly shaped, blackish blotches; and
when conditions are favourable for the growth of the
parasite, the leaves are frequently killed while quite
young.

The dark-coloured mycelium spreads in the leaf or fruit
between the cuticle and the epidermis, the cuticle being
eventually ruptured, and myriads of very short branches
protrude, each bearing a conidium at its tip. The disease is
extended throughout the season by means of these conidia.

APPLE SCAB 303

The disease is tided over the winter by means of the
mycelium present in fallen fruit. Goethe, a German
observer, states that an ascigerous form of fruit is produced

Fig. 80. — Fiisicladium dendriticum. i, appearance
of fungus on the upper surface of an apple leaf; 2, the
fungus on an apple ; 3, conidia, a, borne on the tips of
conidiophores, b, x 300.

on the diseased patches, which matures the following
spring.

PREVENTIVE MEANS. — The following method for combat-
ing the disease is recommended by Professor Galloway : —
'Spray with Bordeaux mixture : first, just as the flower-buds

304 PLANT DISEASES

begin to open ; second, when the petals of the flowers are
falling; and third, when the fruit is the size of peas or
slightly larger. If the season be rainy a fourth treatment
should be given twelve days after the third. Four ounces
of Paris green added to each fifty gallons of the mixture at
the time of the third spraying will hold the codlin moth in
check. The Paris green should first be made into a thin
paste by adding a little water. This paste readily unites
with the mixture, and does not seem to decrease its value
in any way.'

Experience has shown that ordinary Bordeaux mixture
is apt to scorch the foliage, especially when young, hence
it is advisable to use the dilute form.

In cases where the disease has existed previously, the
trees should be thoroughly drenched with a solution of
sulphate of iron during the winter, commencing with the
Bordeaux mixture when the leaf-buds are just expanding.

Galloway, Rep. U.S. Dept. Agric., 1887, p. 341, figs.
Goethe, Gartenflora^ 15 Mai 1887.

PEAR SCAB

(Fusicladium pirinum, Libert.)

This parasite closely resembles in structure and habit
apple scab (Fusicladium dendriticum\ and by some
mycologists is considered as a form of the last-named.
Others, however, look upon the two as distinct, but closely
allied. At all events, the injury done to the foliage and
fruit of the pear is sometimes very severe, especially during
a cool, damp season.

PEAR SCAB

305

PREVENTIVE MEANS.— Similar to those recommended
under 'Apple Scab.'

Goethe, Gartenflora, 15 Mai 1887.
\[

Fig. Zi.—Fusicladitim firinum. i, fungus on the
upper side of a pear leaf; 2, fungus on a pear; 3,
conidia, a, borne on the tips of conidiophores, b, x 30*0.

SWEET-CHESTNUT DISEASE
(Acrosptira mirabilis. Berk.)

The ripe fruit of the sweet-chestnut (Castanea vesca,
Gaertn.) is sometimes filled with a dense blackish-olive
felt belonging to the fungus named above. Nothing as to
the life-history of the parasite is known. The disease

U

306 PLANT DISEASES

appears first at the apex of the fruit, and inoculation
probably takes place through the stigma.

GUMMOSIS OF PRUNUS JAPONICA
(Cladosporium epiphyllum, Fr.)

During two successive seasons a considerable number of
examples of the beautiful flowering shrub, Prunus japonica,
Thunb., growing in Kew Gardens, were either killed or
much injured by a disease agreeing in nature with what
has been termed gummosis. Stout branches are most
frequently attacked; the disease is indicated by the
appearance of tearlike drops of almost colourless gum
oozing from the branches. The drops are solitary or crowded,
and rapidly increase in size, eventually forming irregularly
nodulose masses varying in size from a marble to that of a
walnut. During damp weather the masses are soft and
gelatinous, with just sufficient consistency to hold together,
whereas in dry weather they shrink considerably and
become horny. Finally the masses are dissolved and
washed to the ground by rain.

As already stated, the small drops are colourless,
gradually changing from grey to black as they increase in
size. If a large black mass is hardened by placing it in
methylated spirit, and then cut through, it will be seen that
the surface alone is black, the colour gradually becoming
lighter inwards, and white at the centre.

This extrusion of gum is entirely due to the action of a
minute fungus which does not differ structurally from the
exceedingly common Cladosporium epiphyllum. Repeated
experiments prove that the fungus is a wound-parasite,
gaining an entrance into the tissues through small wounds

GUMMOS1S OF PRUNUS JAPONICA 307

in the bark, broken branchlets, and more especially at those
points where leaf-buds or flower-buds have been broken
off by birds. An olive patch of Cladosporium first appears
at the diseased point, and after the conidia are dispersed the
drop of gum appears, and into this gum the hyphae of the
fungus extend, keeping pace with its increase in size, but
not projecting beyond the surface of the gum-mass. The
hyphae at first are colourless and very slender, but as the
mass increases in size the tips of the hyphae nearest the
circumference become tinged olive, and broken up into
short, irregularly shaped chains of cells. When the mass
has reached its full size, the peripheral portion is densely
crowded with the coloured chains of cells, many of which
produce dense masses of cells or micro-sclerotia with thick,
dark-brown walls. When this stage of development has
been reached, if the mass remains damp and distended,
the large brown cells and micro-sclerotia give origin to
myriads of very minute hyaline conidia which are con-
tained in the dense gum-mass, and have been produced
in the absence of oxygen, or in an anaerobic manner. If
conditions remain unchanged, the minute conidia, when
liberated from the mother-cell, increase at a rapid rate by
germination, or in a yeastlike manner, until finally the
originally black surface of the mass becomes white and
opalescent. Eventually the mass is washed to the ground
by rain, and there the conidia continue to reproduce
themselves by gemmation.

After a gum-mass has been removed, a large cankered
wound, sometimes extending to the pith, is revealed.

On the other hand, if the black masses are washed to
the ground by rain, and dissolved before the commence-
ment of the production of conidia, the large brown cells and

§

• • f // 1

H

[For description see p. 309.

GUMMOSIS OF PRUNUS JAPONICA 309

micro-sclerotia, fully exposed to the air, produce a chain of
two or three very large, colourless cells, and these in turn
bear numerous smaller, elliptical conidia. When mature the
conidia become free and reproduce themselves quickly by
gemmation. This condition of conidia formation corre-
sponds to the stage known as Dematium pullulans^ De
Bary, and is the aerobic mode of reproduction of the
Cladosporium.

Numerous pure cultures of the various phases described
above were made, and inoculations with the olive conidia
of the ordinary condition of Cladosporium^ and also with
the conidia of the aerobic stage, produced the disease.
Inoculation with conidia of the anaerobic condition gave
no result.

This is the first instance where gummosis has been
directly proved to be caused by a fungus.

PREVENTIVE MEANS. — Diseased branches should be
removed, or, better still, collar-pruning should be resorted

Fig. 82.— Cladosporium epiphyllum. i, portion of a branch of Prunus
japonica, bearing two masses of gum, half nat. size ; 2, Cladosporium form
of fruit, x 250 ; 3, section of a portion of the periphery of a black gum-
mass, showing the hyphae of the Cladosporium, x 50 ; 4, dark-coloured
tips of hyphae from the periphery of a gum-mass, bearing large, thick-
walled, brown cells, X25o; 5, large thick-walled cells germinating in a
nutrient solution in the absence of air, and producing yeastlike cells, which
reproduce themselves by gemmation, X25o; 6, stray cells emitting a
germ-tube, seen in the material described under 5 ; 7, micro-sclerotia
germinating under conditions similar to those described under 5, and
producing similar conidia, x 400 ; 8, large, brown, thick-walled cells
germinating in a nutrient solution, with free access of air, and producing
the form of fruit known as Dematium pullulans, x 250 ; 9, conidia of the
Dematium increasing by germination, X25o; 10, fragments of sporophores
of Cladosporium producing a slender form of Dematium pullulans, x 250 ;
ii, a form of Macrosporiiim often appearing on old canker-spots caused
by the Cladosporium : no genetic connection between the two could be
established, x 300 ; 12, spore of Macrosporium germinating, x 400. (From
Kew Bulletin.}

310 PLANT DISEASES

to; and to prevent a recurrence of the disease from conidia
present in the soil, the surface soil should be removed and
fresh soil added, with a layer of quicklime on the surface.
Massee, Kew Bulletin, 1899, p. i, i pi.

PLUM SCAB

(Cladosporium carpophilum, Thiimen.)

This disease has received the name of 'scab' in the
United States. It attacks the fruit of cultivated plums,
cherries, and almonds. On half-grown fruit the fungus
forms greyish or olive-brown spots, which extend radially;
when numerous the fruit shrivels, and often cracks.

PREVENTIVE MEANS. — Bordeaux mixture has been sug-
gested for checking the disease ; it should contain a little
treacle or soap to secure adhesion. Spraying should cease
when the fruit commences to ripen.

Pammel, Iowa Agric. Coll. Expt. Station, Bull. No. 23,
p. 918, 2 figs. (1894).

LEMON AND ORANGE SCAB

(Cladosporium citri — pro tern.}

This disease, so fully described and illustrated by
Swingle and Webber, proves very injurious to lemon and
orange trees in Florida and Louisiana. The disease is
indicated by the presence of numerous small warts or
excrescences on the leaves and fruit. When the fruit is
attacked quite young, the warts are often numerous, and
measure up to J-inch high and across, although often
smaller. The disease is caused by a minute fungus, which
covers the warts with a delicate mould, grey at first, then

LEMON AND ORANGE SCAB 311

dusky, finally black. Trees growing in low, moist situa-
tions are most subject to scab ; in fact, the spread and
development of the fungus requires the almost constant
presence of moisture in the air. The sour orange (Citrus
bigaradid) is especially susceptible to this disease.

PREVENTIVE MEANS. — Spraying with ammoniacal solu-
tion of copper carbonate is effectual ; so is Bordeaux
mixture, but the latter is more or less injurious to the
foliage and fruit. Spraying should commence when the
fruit is just set, and continued at intervals.

All diseased fruit, whether on the ground or still on the
tree, should be collected and burned.

Sour orange-trees should be cut down, also all shoots
from sour stocks.

In planting avoid low-lying, damp situations.

The fungus causing this disease has been referred to by
the authors as Cladosporium sp. I have added the specific
name citri^ not for purposes of priority, but for convenience
of reference to the diagnosis in the systematic appendix.

This Cladosporium species is evidently quite distinct
from Cladosporium e/egans, Penzig, which forms arid,
brown spots on living leaves of oranges in Italy.

Lamson-Scribrier, Bull. Torrey Bot. Club^ vol. xiii. p.
181.
Swingle and Webber, U.S. Dept. Agric., Bull No. 8.

TOMATO LEAF RUST

(Cladosporium fulvum, Cke.)

This disease often proves destructive to tomatoes both
in Europe and the United States, especially where the
plants are grown under glass. The leaf is the part most

312

PLANT DISEASES

frequently attacked, although the fungus sometimes passes
on to the young fruit also. Small brown spots appear first
on the young leaves, which gradually increase in size until
the greater part of the surface is covered ; the leaves
gradually become blackish-brown, shrivel, and die. The

Fig. 83. — Cladosporium fulvum. i, under surface of a
diseased tomato leaf; 2, a tuft of conidiophores bearing
conidia, x 300.

under surface of the leaf corresponding to the dark patches
is covered with a short felt of a rusty-brown colour. This
felt consists of closely packed, sparingly branched clusters
of coloured conidiophores bearing elliptical, one-septate
conidia at their tips. The sporophores are knotted or
swollen at the joints. Blackish stripes are often present
on the stems of diseased plants.

TOMATO LEAF RUST 313

PREVENTIVE MEANS. — Spraying with dilute potassium
sulphide solution, or with dilute Bordeaux mixture, will
check the disease if resorted to sufficiently early, and
repeated at short intervals. If the disease has previously
existed, spraying should be commenced before the disease
appears. Diseased plants should be removed to prevent
an epidemic.

Plowright, Card. Chron., Oct. 29, 1887, figs.
Galloway, Ann. Rep. U.S. Dept. Agric., 1888, p. 347,
i pi.

Cladosporium elegans, Penzig. — This fungus appears as
minute blackish tufts seated on arid spots on living orange
leaves in Italy. The specific diagnosis proves this to be
distinct from the United States species, causing 'scab'
on leaves and fruit of the lemon. To which species the
fungus causing a somewhat similar disease in Japan and
Australia belongs, cannot be determined in the absence of
specimens.

MAIZE BLIGHT

(Helminthosporium turricum, Pass.
= Helminthosporium incotispicuum, Cke. and Ellis.)

This fungus often proves destructive to maize or Indian
corn (Zea mays), and has been recorded from Southern
Europe, Queensland, and the United States. Small pale
patches appear on the leaves, and continue to increase
in size and run into each other, forming large patches, until
finally the greater portion of the blade is covered, the
midrib alone remaining rigid. The spots finally change to
a pale brown, often with a darker border, and are more or
less covered at this stage with a very delicate dusky mould,

314.

PLANT DISEASES

which when magnified is seen to consist of pale olive
upright conidiophores, each bearing at its apex or tip a
large spindle-shaped, many-septate, pale olive conidium.

In some cases the blotches become much elongated, and
do not run into each other. The mycelium spreads in the

Fig. 84. — Helminthosporium turcicum. i, portion
of an Indian corn leaf, diseased ; 2, a tuft of conidio-
phores bearing two conidia, x 300.

tissue, which finally becomes dry and brittle. The appear-
ance of the fruiting condition on the surface of the leaf
depends much on climatic conditions; if uninterruptedly
warm and moist, the leaves often become brittle, and fall
to the ground in fragments before the conidia are formed ;
these however do develop on the pieces lying on the ground.

MAIZE BLIGHT 315

On the other hand, if warm weather is suddenly followed
by a chill, fruit is usually formed in abundance. The disease
may appear during any period of growth of the host.

PREVENTIVE MEANS. — A difficult disease to combat;
perhaps burning after the corn has been gathered would be
to a certain extent effective in preventing a return of the
disease the following season. The most certain means of
effecting this, however, would be by the rotation of crops ;
and as maize impoverishes the soil to a very marked extent,
this course is, under all circumstances, advisable.

Bancroft, Proc. Roy. Soc. Queensland, vol. iii. p. 108.

Helminthosporium gramineum, Erikss. — Forms elongated
olive blotches on leaves of barley, the injury done being
in proportion to amount of fungus present.

Helminthosporium feres, Sacc. — Also attacks the leaves
of barley, forming long olive blotches, and causing the
leaves to shrivel.

A form of this species — Forma Avenae sativae, Briosi
e Cavara — forms numerous narrow, elongated, dry patches
on the leaves of oats, and when in profusion arrests the
maturing of the fruit.

SEEDLING PEA BLIGHT

(Brachysporium pisi, Oud.)

Oudemans has described a disease which proves de-
structive to young pea plants (Pisum sativum}.

The leaves show blackish mouldy patches, become
yellow, and soon die. The dark patches consist of myriads
of upright dark threads, each bearing a coloured, elliptical,
three-septate conidium at its tip.

Preventive measures are not given, but probably dilute

3i6 PLANT DISEASES

Bordeaux mixture, or potassium sulphide solution, which
has proved effective against allied fungi, would arrest the
spread of the disease.

Oudemans, NederL Bot. Yen., 1898, p. 527.

CELERY LEAF BLIGHT

(Cercospora apii, Fr.)

During a damp season celery leaves often show pale
spots which rapidly increase in size and often cover the
greater portion of the leaf. The portion not attacked

Fig. 85. — Cercospora apii. i, celery leaf attacked by the fungus;
2, fruit of fungus, x 300.

turns yellow, and the leaf dies. As a rule the disease
spreads rapidly unless checked by a spell of dry weather,

CELERY LEAF BLIGHT . 317

which prevents the spores germinating on the leaves.
The fruit-bearing branches of the fungus come through
the stomata of the leaf and produce spores on the surface.
When the greater part of the foliage is thus destroyed, the
crop is a failure.

PREVENTIVE MEANS. — Spraying with an ammoniacal
carbonate of copper solution has been proved to be
effectual in checking disease, but it is very important to
commence quite early, as the plants are most susceptible
to the disease when quite young.

Professor Galloway states that spores found on frag-
ments late in spring germinated readily, hence all dis-
eased leaves should be collected and destroyed.

Galloway, Ann. Rep. Commis.of Agric., U.S.> 1886, i pi.;
also in Rep. 1888, p. 398.

Halsted, N. Jersey State Ag. Expt. St. Rep. 1891,
p. 250, fig.

'SHOT-HOLE FUNGUS'

(Cercospora circumscissa^ Sacc.)

This well-known pest attacks the leaves of peach, apricot,
cherry, almond, and nectarine. Small circular patches of
the leaf, bearing conidia on one or both surfaces, become
dry, contract, and drop away, leaving a hole in the leaf;
numerous such holes are often present on a single leaf,
giving it the appearance of having been riddled with small
shot. Such diseased leaves fall early in the season before
the formation of wood has been completed, consequently
there is a poor crop of fruit the following season. The
young branches, and even the fruit of the peach, are some-
times attacked. The disease often spreads quickly, being

318 PLANT DISEASES

favoured by the dispersion of the dropped-out portions of
the leaf bearing conidia.

PREVENTIVE MEANS. — Spray with ammoniacal solution
of copper carbonate, the first time just when the leaves

Fig. 86. — Cercospora circumscissa. i, peach leaf diseased ; 2, cluster
of conidiophores bearing conidia, X4oo.

are expanding, and repeating at intervals. Bordeaux mix-
ture should not be used for peach or almond, as the leaves,
and even young shoots, are injured by dilute solutions.

Pierce and Galloway, Journ. Mycol., vol. vii. p. 66, 4 pi
(1894).

MIGNONETTE DISEASE 319

Cercospora viticola, Sacc. — Forms irregular, dry, brown
spots on vine leaves, and is most abundant during a damp
season. The discoloration extends through the leaf. Most
abundant on the lower, shaded leaves.

Cercospora beticola, Sacc. — Forms irregular, dry, pallid
blotches on leaves of beet (Beta vulgarts). Can be held
in check by spraying with Bordeaux mixture.

MIGNONETTE DISEASE

(Cercospora resedae, Fuckel)

This fungus often proves destructive to cultivated
mignonette, especially when grown under glass, causing
dry brownish spots to appear on the leaves. It can be
controlled by spraying with Bordeaux mixture.

Cercospora violae, Sacc. — This species causes dry, pallid
spots to form on the leaves of Viola odorata, the sweet
violet, and often proves troublesome when the plants are
grown under glass. Spray with dilute Bordeaux mixture.

FAIRY-RING OF CARNATIONS

(Heterosporium echinulatum, Cke.)
This disease often proves destructive to cultivated
carnations and pinks, especially when the plants are ex-
posed to a chill, or when a moist, warm period in spring
is followed by a sudden lowering of temperature.

The characteristic arrangement of the small black
clusters of the fruit of the fungus in irregular circles,
seated on pale spots on the leaf, resembling the 'fairy-
rings ' formed in pastures by Marasmius oreades, renders
the determination of this disease quite certain, even
without microscopic examination.

320 PLANT DISEASES

Numerous minute sclerotia are formed in the dying
leaves; these remain in a passive condition until the

W •:*

Fig. 87. — Heterosporium echinulatum. i, portion of a
diseased carnation ; 2, a small tuft of fungus fruit, showing
the large, minutely warted, septate spores borne singly at the
tips of crooked sporophores ; a, portion of a compact mass
of mycelium from which the cluster of conidiophores spring,
and which eventually forms a sclerotium, XSQO; 3, a spore
that has germinated in water ; the germ-tubes bear short
branchlets, each of which produces a dark-coloured secondary
spore at its tip, x 300.

following season, when they produce minute conidia,
which, when placed on living leaves of carnation, give
origin to the first patches of disease.

FAIRY-RING OF CARNATIONS 321

PREVENTIVE MEANS. — Spraying with potassium sulphide
checks the disease. All diseased leaves should be picked
off and burned. By consistently attending to this point,
the disease does not spread, and the danger of a re-
appearance of the disease the following season is much
diminished.

When plants are grown under glass, the foliage
should be kept as free from moisture as possible, as, if
the surface is dry, floating spores alighting on the leaves
do not germinate. Secure good ventilation, and avoid
watering the foliage.

Smith, Gard. Chron.^ 1886, p. 244, fig.

Heterosporium grari/e, Sacc. — Often disfigures or kills
the leaves of cultivated species of Iris, Freesia^ Antholyza,
and Hemerocallis.

The mycelium is localised, but as the diseased spots —
elliptical, pale brown, with a darker margin — are often
abundant, and also large, up to half an inch long, attacked
leaves soon die. The pale spots eventually become
studded with the minute olive-brown tufts of conidio-
phores, bearing the large, warted conidia at their tip.

Damage has been done to members of one or other of
the above-named genera in Europe, Cape of Good Hope,
New Zealand, and United States.

PREVENTIVE MEANS. — Spraying with ammoniacal copper
carbonate solution checks the disease — at least, when
present on Freesia recurva. I have not experimented in
the case of other genera. Clear away diseased leaves,
and do not disperse the conidia in so doing.

322

PLANT DISEASES

CARNATION MACROSPOEIUM

(Macro sporium nobile, Vize.)

As seen with the naked eye, this fungus forms minute,
dark-coloured spots on the stem and both surfaces of the
leaves of cultivated carnations. The spots are irregularly

\ * I 'I !."»

Fig. 88. — Maerosporium nobile. i, portion of a car-
nation showing the disease ; 2, two conidia, x 300 ; 3,
portion of a conidium germinating, x 300 ; 4, Ftts-
arium spores, x 400.

scattered, and the mycelium is widely diffused in the
tissues before these spots or clusters of conidia appear
and burst through the epidermis. The conidia are large,
pale olive-brown, and consist of many cells joined to-
gether. Later in the season numerous minute black
sclerotia are imbedded in the diseased parts of the plant.

POTATO LEAF CURL 323

PREVENTIVE MEANS. — Spraying with a solution of
ammoniacal copper carbonate, or of potassium sulphide,
arrests the spread of the fungus. The wisest plan is to
remove diseased plants before the conidia diffuse, and by
picking off the leaves the formation of sclerotia is pre-
vented. If stems are also attacked they should be cut off.

POTATO LEAF CURL

(Macrosporium solani, Cooke.)

The well-known disease of the foliage of potatoes known
as ' leaf curl ' attacks the stem, usually close to the ground
at first, and gradually creeps up, first causing the leaves to
curl, and finally the stem also collapses. When the leaves
first curl, there is usually no external sign of the fungus,
but at a later stage the stem and leaves become more or
less studded with blackish, minutely velvety patches.

These dark patches are due to the production of in-
numerable conidia on the surface of the host. The
conidia are large, olive-brown, and divided into numerous
cells by septa crossing at right angles.

This fungus is closely allied to, if not identical with,
the Macrosporium causing ' black stripe ' or blotch on the
tomato.

PREVENTIVE MEANS. — The spores persist through the
winter on fragments of leaves and stems ; hence, to prevent
a repetition of the disease, it is essential the potato ' tops '
should be carefully collected and burnt in the autumn.

Spraying with dilute Bordeaux mixture, if commenced
sufficiently early, prevents the disease from doing serious
mischief.

324 PLANT DISEASES

TOMATO BLACK ROT

(Macrosporium tomato^ Cooke.)

This disease appears to be present wherever the tomato
is cultivated. The fruit is most frequently attacked, but
the fungus is also often present on the stem and leaves.
The fungus is a wound-parasite, and on the fruit most
frequently effects an entrance through minute cracks round

Fig. 89. — Macrosporium tomato, i, a diseased tomato ;
a, conidia of the fungus in various stages of develop-
ment, x 300.

the style, or at the point of insertion of the stem, but may
appear on any part of the fruit where a puncture of the
skin large enough to admit of the entrance of the germ-tube
of a spore is present. A dark-coloured mycelium forms
in the tissues, and rapidly destroys the cells, consequently
the area occupied by the fungus sinks a little below the
general surface of the healthy part of the fruit. At a later
stage the sunken surface of a diseased spot becomes covered
with a delicate, velvety pile of a brownish or blackish-olive
colour. Microscopic examination shows this pile to consist

TOMATO BLACK ROT 325

of closely packed, dark-coloured conidiophores, each bear-
ing a dark, many-celled conidium at its tip.

When mature, the conidia germinate quickly in water,
each cell of the spore producing a germ-tube capable of
inoculating a tomato if placed on a wounded surface. The
present fungus is suspected of being a condition of some
higher form, but this has not yet been definitely proved.

PREVENTIVE MEANS. — Thorough spraying with potassium
sulphide solution at frequent intervals. All diseased parts
should be cleared away and burned, otherwise they con-
tinue to grow on shrivelled fruit, stems, and leaves. The
use of green stable manure is considered to favour the
disease, and also causes the fruit to crack, thus rendering
it susceptible to a high degree.

Smith, Gard. Chron., Oct. i, 1887, fig. 89.

Plowright, Gard. Chron.^ Nov. 12, 1881, figs. 118, 119,
122.

Galloway, Ann. Rep. U.S. Dept. Agric., 1888, p. 339,
pi. iii.

IBIS BULB SCAB

(Mystrosporium adustum, Massee.)

Bulbs of Iris reticulata are frequently destroyed by a
fungus which forms black crustaceous patches on the
outer sheath, the hyphae gradually extending to every
part. The conidia are very large, dark brown, and divided
into a number of cells by cross-walls or septa.

PREVENTIVE MEANS. — If only slightly attacked, soaking
the bulbs for two hours in a solution of one part of formalin
to three hundred parts water will destroy the fungus before
it enters the deeper parts of the bulb.

326 PLANT DISEASES

Diseased bulbs should be collected and burned to prevent
the dispersion of conidia.

Mystrosporium alliorum, Berk. — This species sometimes
forms dark patches on onion bulbs.

Mystrosporium abrodens, Neumann. — Said to be destruc-
tive to the wheat crop in some districts in France. Dark
patches are formed in the leaves and nodes, the latter
becoming weak. The plant bends over. The ears are
imperfectly developed.

Neumann, Soc. Biol. Toulouse, 1892.

THREAD BLIGHT OP TEA PLANT

(Stilbum nanum, Massee.)

Indian tea-planters have known this most destructive
fungus for at least the last thirty years. The name ' thread
blight' is given on account of the very thin strands or
films of white mycelium that are firmly attached to the
branches and under surface of the leaves of the tea plant.
The mycelium also runs under the surface of the branches,
living in the tissues of the bark, and coming to the surface
here and there to spread over the outside of leaves and
twigs.

The fruit only appears to be formed on very old, rotten
branches that have fallen to the ground and become
decayed, and resembles pins in miniature — a very slender
stem and a round head, the whole not half a line high.
Repeated observation proves the fruit to be very rare,
and infection from spores may be left out of consideration,
except in the case of reclaimed ground, where the trees
have been neglected for some time.

THREAD BLIGHT OF TEA PLANT 327

The amount of evidence forthcoming seems to suggest
that the mycelium travels underground, and first attacks
the root, afterwards passing up the stem, either externally
or internally, always finally coming to the surface.

PREVENTIVE MEANS. — It seems to be generally admitted
that thread blight is common in the jungle on various
plants; and to prevent its spread to the tea plants, narrow
trenches should be kept open. These need not be very
deep, as underground mycelium runs near the surface.
By similar means, diseased patches in the plats should be
isolated. Prunings should be burned and not buried, as
each buried mass may prove a centre of infection. If
quicklime is available, and not in other respects injurious
to the tea plant, a shallow trench should be made round
the stem, filled with lime, or lime mixed with sulphur, and
covered over with soil.

Spraying with Bordeaux mixture or with potassium
sulphide would check the external spread of the mycelium
on the plant.

Watt, Pests and Blights of the Tea Plant, p. 433.
Cunningham, Scientific Mem. Med. Officers of Army of
India, pt. x. p. 20.

Massee, Kew Bulletin, 1898, p. in, figs.

COFFEE TWIG DISEASE

(Necator decretus, Massee. )

Bursting through the epidermis of young shoots as
minute white spots, which soon become orange-red and
gelatinous. Said to be a destructive parasite on coffee
trees at Singapore. Commencing at the tips of young

328 PLANT DISEASES

branches and extending downwards. Removing diseased
branches checks the spread of the disease.

Massee, Kew Bulletin, 1898, p. 119.

SLEEPING- DISEASE OF TOMATO

(Fusarium ly coper siti, Sacc.)

This disease was first recorded from Guernsey, where
the culture of tomatoes constitutes at present the principal
source of revenue. It has also been recorded quite
lately from widely separated localities in Britain. In some
instances where only a small area is under cultivation, the
annual loss has amounted to ^300, and in some instances
an average-sized house containing tomatoes will, if attacked
by the disease, mean the loss of ;£ioo to ^200 in a
season.

The disease is indicated by the dull colour of the leaves,
which commence to droop ; this is quickly followed by a
collapse of the stem, hence the name ' sleeping disease.'
If the plants are not attacked until the fruit is present,
this frequently ripens, and to the naked eye, or even when
examined microscopically, appears to be free from disease;
nevertheless it is well known that seed obtained from dis-
eased plants produces diseased seedlings.

The root is invariably attacked first, the fungus gaining
an entrance through the rootlets, gradually extending to
the taproot and lower portion of the stem. Its presence
is indicated to the naked eye by a brown discoloration
of the vascular bundles, and when this stage is reached
the plant droops, or ' sleeps.' Shortly after the sleeping
stage has been reached, the portion of stem just above
ground is more or less covered with a very delicate white

SLEEPING DISEASE OF TOMATO

329

mould. This mould consists of fruiting branches or coni-
diophores which bear conidia at the tips of their whorled
branches. The conidia fall to the ground, where they

Fig. 90. — Fusarium lycopersici. i, Diplocladium
stage, XSQO; 2, Fusarium stage, X3Oo; 3, resting-
spores,

germinate, producing a mycelium which attacks the root-
lets of tomato, and continue the disease.

This is the first, or Diplocladium stage of the fungus,
which is quickly followed by the second, or Fusarium con-
dition, which forms from the same mycelium that pre-
viously produced the Diplocladium. The spindle-shaped,
curved spores of the Fusarium stage are produced in

330 PLANT DISEASES

immense numbers and germinate quickly, hence the very
rapid spread of the disease can be readily understood.

It is somewhat remarkable that the young rootlets of
the tomato are the only part of the plant through which
the fungus can gain admission to its interior. All attempts
to inoculate above-ground portions with either Diplo-
cladium or Fusarium spores have failed.

The probable explanation of this is that the fungus
commences life as a saprophyte, and afterwards becomes
parasitic. Numerous strands of mycelium are also present
in the soil, where they spread, and in due course produce
a third form of fruit, known as resting-spores. These
remain dormant for a season and then germinate, forming
a mycelium capable of attacking the rootlets of tomatoes.
By this means the disease is communicated to a new crop
of tomatoes the following season.

PREVENTIVE MEANS. — Owing to the mode of attack,
spraying with fungicides is of no avail. It is considered
fortunate by growers if even a small quantity of fruit is
obtained from a diseased crop ; but this is obviously un-
sound reasoning, especially where tomatoes are grown in
the same house and in the same soil year after year, for
the simple reason that when a diseased crop is allowed to
stand and mature its fruit, resting-spores innumerable are
produced in the soil, ready to attack the succeeding crop,
which in turn can only yield a very small quantity of
fruit.

Plants should be removed on the first symptoms
of disease, and the soil mixed with quicklime. Where the
plants in a house have been badly diseased, all the soil
should be removed, and the walls, etc., drenched with a
solution of iron sulphate.

RED MOULD OF BARLEY 331

Seed obtained from diseased plants, or from a neigh-
bourhood where the disease prevails, should not be used.

Massee, Gard. Chron., June 8th, 1895 ; also repeated in
Journ. Roy. Hort. Soc., vol. xix. pt. i, figs. (1895).

Collenette, Journ. Roy. Hort. Soc.^ vol. xix. pt. i (1895).

RED MOULD OF BARLEY

(Fusarium heterosporum, Nees.
=• Fusisporium hordei, W. G. Sm.
=Ftisisporium lolii, W. G. Sm.)

Not uncommon on barley and rye, also occurring on
maize and on several other grasses, as rye grass (Lolium)
Holcus, Paspalum, Panicum, and Molinia. Met with in
Europe, South Africa, and United States. The grain is the
part attacked, and this is distorted and swollen by the dense
tufts of sporophores which burst through the pericarp,
and form an orange, crimson, or deep red subgelatinous
mass on the surface of the fruit. The sporophores are
branched, each branchlet bearing at its tip a slender, colour-
less, sickle-shaped spore, which usually becomes five-
septate at maturity. Barley attacked by the fungus
becomes valueless for malting purposes. A pure culture
of the mould placed in sterilised beer-wort of specific
gravity 1.057 gave rise to a peculiar ferment, producing
alcohol and carbonic acid gas.

PREVENTIVE MEANS. — Use healthy seed not obtained
from a district where the disease is known to occur, and
be especially careful to prevent contamination from the
fungus living on wild grasses growing in ditches or hedge-
rows.

332

PLANT DISEASES

Matthews, Journ. Roy. Microscop. Soc.^ 1883, p. 321,
2 pi.

Smith, Diseases of Field and Garden Crops, p. 209, figs.
Frank, Jahrb. d. Deutsch. Landwirth. Gesell., 1892.

Fig. 91. — Fusarium heterosporum. i, portion of an
ear of rye showing diseased grains; 2, diseased grains ;
3, portion of a diseased grain showing the dense clusters
of sporophores on its surface, slightly x; 4, spores,

FOOT-ROT OF OEANGE AND LEMON

{Fusarium limonis, Briosi.)

A fungus causing considerable injury to orange and
lemon trees in Europe and the United States. Its pres-
ence is indicated by the exudation of masses of gum near
the base of the trunk. The diseased patches are small at
first, but gradually increase in size, spreading round the
trunk and passing into the roots, extending through the
bark and cambium into the wood, killing the tissues. At
the same time the leaves are few in number, small, and
yellowish, and many of the smaller branches die.

RED MOULD OF WHEAT 333

This disease is known as 'mal-di-gomma' in Italy, and
' foot-rot ' in Florida.

PREVENTIVE MEANS. — Remove the soil from the base
of the trunk, and cut away the diseased patches, paint-
ing the wounds with some fungicide. Good drainage is
essential.

Briosi, Men. della R. Acad. Lincei, 1878.
Webber and Swingle, U.S. Americ. Dept. Agric., Bull.
No. 8 (1896).

BED MOULD OP WHEAT

(Fusarium culmorum^ W. G. Sm.)

This fungus attacks wheat, forming cream - coloured,
yellow, or orange subgelatinous expansions on the ear,
gluing the spikelets together, and arresting the growth of
the grain. The spores are larger than those of F. hetero-
sporum, fusiform, 3-5-septate, orange, soon breaking up at
the septa.

Smith, Diseases of Field and Garden Crops, p. 208, figs.

Fusarium solani, Sacc., is said to cause the rotting of
potato tubers, but the matter requires further investigation.

Fusarium pannosum, Massee. — This remarkable fungus
forms broadly effused, felty, gelatinous expansions of a
clear vermilion colour on the living trunk of Cotnus
macrophylla. Wall., in the Punjab.

OLIVIA LEAF BLOTCH

(Chaetostroma cliviae, Oud.)

Yellow blotches of large size and varied form appear on
the leaves of Clivia nobilis^ at first towards the margin,

334 PLANT DISEASES

and finally scattered over the entire surface. At a later
stage these blotches are studded with minute black spots
or stromata, which on being magnified are seen to be
bordered with a fringe of black, pointed hairs. The con-
idia are long, narrowly cylindrical, and colourless. No
preventive measures appear to have been tried, but
probably the spread of the disease could be checked by
cautious spraying with a fungicide, very dilute to com-
mence with, until its action on the foliage is observed.

Oudemans, Comp.Rend. Acad. Roy. Sci. Pays-Basy 1896,
p. 226.

MYXOGASTRES

' FlNGER-AND-TOE '

(Plasmodiophora brassicae, Woronin.)

This destructive disease, known in different parts as
'finger -and -toe,' 'club-root,' and 'anbury,' attacks the
various kinds of cabbage, turnips, radishes, wallflowers,
in fact most cultivated plants, as well as weeds belonging
to the Order Cruciferae.

The root is the part most frequently attacked, the
presence of the parasite being indicated by the formation
of numerous nodules, or wartlike outgrowths, or the entire
root becomes swollen and clubbed, eventually rotting and
emitting a very disagreeable smell.

The disease also exists in the leaves, at least in the case
of cabbages, but no distortion occurs, as in the root.

Berkeley appears to have been the first to investigate
the disease; and, although he failed to determine the
true cause, was convinced, as the result of microscopic

"N

\

Fig. 92. — Plasmodiophora brassicae. i, a young turnip
showing the early stage of the disease ; 2, a cabbage plant
with clubbed root ; 3, two diseased cells from the root of
a cabbage, one contains plasmodium, the other is crowded
with the minute spores of the parasite ; 4, three myxa-
moebae or motile bodies produced by the spores on
germination, very highly mag.

336 PLANT DISEASES

examination, that the organism concerned differed from
anything previously connected with plant disease.

Woronin, a Russian botanist, was the first to clearly
work out the life-history of the organism causing the
disease, his attention being called to the subject by the
offer of a reward by the Russian Government for the dis-
covery of the serious disease affecting the cabbage crop in
that country.

The disease is contracted in the first instance by spores
present in the soil, which enter the living cells of the root
of the host. When once inside a living cell, the parasite
does not form a mycelium as in the fungi, but a glairy
mass of protoplasm called a plasmodium, which slowly
alters its form from time to time, and constitutes the
vegetative condition of the parasite. Cells containing
plasmodium increase enormously in size, and furthermore
the plasmodium passes from one cell to another, devour-
ing their contents. After remaining in the vegetative state
for some time, and producing the swellings in the root
alluded to, the plasmodium undergoes certain changes,
and eventually becomes resolved into myriads of exceed-
ingly minute, round spores, which on the decay of the
root are liberated in the soil. What takes place after the
spores are set free, as to whether they germinate, form a
plasmodium that exists as a saprophyte for some time, is
not known ; but it is known with certainty that if cabbages,
turnips, or other allied plants are sown or planted in soil
that has produced diseased plants the previous season, or
even two or three years previously, such plants will become
diseased.

PREVENTIVE MEANS. — From what has been stated, it
will be seen that it is simply courting disaster sowing or

MYXOGASTRES 337

planting cabbages, turnips, etc., in diseased soil ; on the
other hand, repeated experiments have proved that the
application of quicklime destroys the germs in the soil.
In the New Jersey Agricultural Coll. Experiment Station,
Bulletin No. 98, devoted to the subject, it is stated : ' Lime
is an effective preventive of the club-root, and, by its
constant use, at the rate of seventy-five bushels or so
per acre each year, cabbages have been grown at frequent
intervals — almost yearly — upon the same soil.'

The use of artificial manures containing acids, phos-
phates, and sulphates, favours the spread of the disease.
It has been demonstrated that soil from an infected
locality, carried by means of cart-wheels, tools, etc., is
sufficient to start the disease in a new locality.

Weeds such as shepherd's-purse, charlock, garlic-
mustard, and other crucifers should not be allowed to
grow in places where cultivated plants belonging to the
same Order are. grown.

Do not throw diseased plants on to the manure-heap,
but burn them.

Dr. Halsted states that the plants are most susceptible
to the disease during the first three weeks after germina-
tion, and that thirty - five bushels of lime per acre is
sufficient to arrest the disease.

Woronin, Pringsh. Jahrb., vol. xi., 1878, 6 pi.
Marshall Ward, Diseases of Plants, p. 47, figs.
Eycleshymer, Journ. MycoL, vol. viii. p. 79, 2 pi.
Massee, Proc. Roy. Soc., vol. Ivii., 1895.
Halsted, American Card., vol. xix. p. 373 (1898).

338 PLANT DISEASES

BRUNISSUEE

In Europe and North America a disease of the vine,
characterised by the appearance of brown spots on the
leaves, which eventually extend, and cover more or less the
entire surface, has been considered by Viala and Sauvageau,
as due to the presence of an amoeboid organism in the
cells, to which they have given the name Plasmodiophora
vitis, Viala and Sauv.

The California vine disease is also considered by these
authors to be caused by an organism allied to the last,
which they named Plasmodiophora californica, Viala and
Sauv.

I have demonstrated elsewhere that Brunissure, also
the disease on the leaves of cultivated orchids, known as
'spot disease,' is entirely due to physical causes.

Viala and Sauvageau, Journ. de Botanique, 1892, figs.
Viala, Malad. de la Vigne^ ed. iii.
Massee, Ann. Bot., vol. ix. p. 421, i pi.

BACTERIA
BACTERIOSIS OF TOMATOES

Prillieux has described a bacterial disease of tomatoes,
which is very destructive in the north and central parts of
France ; it has also occurred in England.

Inoculation is supposed to be effected through the style
of the flower, and from this point a blackening of the fruit
extends in circles until the whole is destroyed.

Prillieux, Malad. des Plantes Agric., vol. i. p. 19, fig.

HYACINTH BACTERIOSIS 339

HYACINTH BACTERIOSIS

{Bacterium hyacinthi, Wakker.)

A destructive disease of hyacinths, well known in Holland,
attacks the bulbs in the resting condition, and also shows
itself in the foliage. The presence of the parasite is
indicated by the appearance of yellow spots on the bulb
or leaves, due to the presence of a yellow mucus teeming
with bacteria, located in the vessels and intercellular spaces
of the fundamental tissue. Infection of healthy plants with
this mucilage produces the disease.

Wakker, Onderzoek der Zeikten van Hyacinthen, Haarlem,
1884.
Prillieux, Malad. des Plantes Agric., vol. i. p. 22, fig.

PINK BACTERIOSIS OF WHEAT

(Micrococcus tritiri, Prill.)

A bacterial disease of grains of wheat, indicated externally
by a rose or purplish colour. The colour is brightest and
most pronounced in the superficial layer consisting of
proteids, less marked where starch predominates.

The starch is first attacked, causing the grain to become
more or less hollow, afterwards the gluten, and finally the
cell-walls.

The bacteria are globose or ovoid, depending on the phase
of development, and form a thin, opaque, colourless, nodu-
lose layer lining the cavity in diseased grains.

This is interesting as being the first account of a bacterial
disease of cultivated plants causing real damage.

Prillieux, Ann. des Set. Nat. Bot., 6th sen, vol. viii., 1879;
and in Malad. des Plantes Agric., vol. i. p. 7, figs.

340 PLANT DISEASES

BLACK ROT OF CABBAGE

(Psendomonas campestris, E. F. Smith)

A disease of cabbages and other Cruciferous plants,
known in the United States for the last dozen years, and
also recently detected in England, is diagnosed as follows
by Dr. Erwin F. Smith : —

' This disease may appear on the plant at any stage of
growth, and is characterised by the following symptoms :
Dwarfing, or one-sided growth of the heads, or, if the
disease is very severe and has begun early in the season,
by the entire absence of any heads, and in extreme cases
by the death of the plant. Occasionally the heads rot and
fall off, but this is not a necessary consequence, the soft,
bad-smelling rot being due to the entrance of other
organisms. If the stumps of affected plants are broken
or cut across, a brown or black ring will be observed
corresponding to the woody part of the stem, this being
the part of the stem specially subject to the disease. In
bad cases this blackening may be easily traced upwards into
the centre of the head, and is generally worst on one side.
In the leaves the symptoms usually begin at the margins,
and consist in yellowing of all affected parts except the
veins, which become decidedly brown or black. The leaves
appear to have " burnt edges." '

The disease is caused by a yellow bacterium which enters
the plant above ground, and usually at the margin of the
leaves, through minute openings called water-pores, situated
on the teeth of the margin of the leaf.

Slugs and caterpillars also spread the disease by gnawing
alternately diseased and healthy plants, or by carrying the

BLACK ROT OF CABBAGE 341

germs on their body, and, in crawling, depositing them in
the region of the water-pores.

PREVENTIVE MEANS. — Rotation of crops is the best
means of ridding the soil of the pest. Care should be
taken not to allow Cruciferous weeds to flourish, otherwise
the benefit of rotation of crops is lost, as the weeds may
continue the disease. Slugs and cabbage-feeding cater-
pillars should be kept in check. Removal of infected leaves
in the early stages of the disease should prove beneficial,
as the disease passes down the leaf to gain access to the
stem. Finally, it has been shown that when diseased
cabbages have been converted into manure, the cabbages
manured with this material have shown the disease.

Smith, in U.S. Dept. of Agric., Farmers' Bulletin No. 68 ;
also in Centralb. filr Bakter. Parasitenk. u. Infektionkrank-
heiten, 2 Abt, Bd. iii. pp. 284, 408, 478, pi. i.

OLIVE TUBERCULOSIS

(Bacillus oleae, Trev.)

In Italy and other portions of the Mediterranean region,
olive trees are subject to a peculiar disease caused by a
Bacillus, which causes the formation of irregularly nodulose
tubercles on the branches. These tubercles vary in size
from one-quarter of an inch to an inch in diameter, and
superficially resemble galls of insect origin.

PREVENTIVE MEANS. — Removal of affected branches
checks the spread of the disease.

Savastano, Annuario R. Scuola Sup. d? Agric. in Portia,
vol. v. fasc. 4, 1887.

Voglino, / Fungi Dannosi alle Piante Coltivate, i pi.
Pierce, Journ. My col., vol. vi. No. 4, p. 148, 2 pi.

342 PLANT DISEASES

BACTERIAL DISEASE OF TOMATO, EGG PLANT,
AND IRISH POTATO

{Bacillus solanacearum, E. F. Smith)

Dr. Erwin F. Smith has described in detail a bacterial
disease of the above-named plants in the United States.
Plants belonging to Physalis and Petunia were also proved
to be susceptible to the disease. The disease first causes
the foliage to wilt ; at a later stage the stem and branches
become discoloured and die. On cutting across a branch
in the early stage of the disease the woody cylinder shows
a brownish discoloration, and the vessels are filled with
bacteria, which ooze out at the cut surface in tiny dirty-
white or yellowish drops.

In potatoes the disease passes down the stem and into
the tubers, causing a brown or black rot.

In the egg plant (Solanum melongena) the symptoms are
similar to those in the tomato and potato.

PREVENTIVE MEANS. — The disease has been proved to
be transmitted by leaf-eating insects, the Colorado potato
beetle (Doryphora decemlineata) being used for experi-
menting on the potato ; consequently leaf-eating and leaf-
puncturing insects should be kept in check. Diseased
plants should be removed on the first indication of wilting.
Rotation of crops should be resorted to where the disease
has been present.

Smith, E. F., U.S. Dept. of Agric., Bulletin No. 12,

2 Pl.

LICHENES

Ths larger foliaceous lichens are not parasitic; as to
whether the smaller crustaceous forms that appear to be

LICHENES 343

immersed in the bark, or the numerous species present on
persistent, coriaceous leaves in the tropics, are more or
less parasitic is yet an unsettled question. Apart from
this, it is known that lichens are often injurious to trees
when present on the trunk and branches in quantity, and
this is more especially the case with nursery stock.

It has been shown by Waite that spraying with Bordeaux
mixture of full strength kills the lichens present on pear
trees. This method would, as a matter of course, prove
equally effective in the case of other kinds of trees.

Finely powdered lime sprinkled on the branches during
damp weather is also said to remove lichens.

Cephaleurus mycoidea^ Karsten = Cephaleurus virescens,
Kiinze; Mycoidea parasitica, Cunningham. — This lichen
is abundant on the polished, coriaceous leaves of many
kinds of plants in tropical regions; among genera of
economic importance may be mentioned Coffea, Cituts,
Camellia, Anona> Cinnamomum, and Quassia. Dr. Watt
states that in Assam it may be said to occur on any tree
or bush the leaves of which have, like the tea plant, a fairly
hard and polished epidermis on the upper surface.

On leaves the plant first appears as circular orange
patches ; at a later stage the patches change to green,
or greyish-green, finally becoming white and polished
like porcelain, and are circular or irregularly branched.
Minute black spots are usually present on the white
patches, corresponding to the ascigerous form of the
fungus.

So far as the tea plant is concerned, it appears that so
long as the disease is confined to the leaves but little
injury results, whereas, according to Cunningham, when it

344 PLANT DISEASES

attacks branches it becomes an undoubted parasite, and
kills the parts attacked. As the disease on branches in all
probability in many instances originates from infection by
reproductive bodies formed on leaves in the first instance,
its presence under any circumstances should be regarded
with suspicion. Dr. Watt states that in the present state
of knowledge regarding this blight the following remedial
measures seem worthy of consideration : —

i st. Where shade trees are found to cause the leaves of
tea underneath to be coated with the grey lichenoid
formation and the orange-red algal patches, the trees in
question should be removed.

2nd. Where the leaves of any plot of tea are found to
be abnormally attacked by the alga, they should be plucked
off and destroyed, or washed with Bordeaux mixture. In
neighbourhoods liable to the form that invades the stem,
every orange- red spotted leaf should be carefully removed
and destroyed.

3rd. The seedlings in the nursery, if found to manifest
the orange-red spots, should be washed with the above-
mentioned fungicide, and in districts liable to the stem
invasion they should be dipped into a tub of that fluid at
the time of transplantation.

Cunningham, Trans. Linn. Soc. (Bot.}, ser. n. vol. i.
p. 301, pi. xlii. xliii. (1879).

Marshall Ward, Trans. Linn. Soc. (£>ot.\ ser. in. vol. ii.
p. 87, pi. xviii. xxi. (1884).

Karsten, Ann. Jar d. Bot. Buitenzorg^ 1891, pi. iv.-vi.

Cephaleurus parasiticus, Karsten. — Common on leaves of
Calathea and Pandanus at Buitenzorg, Java. The epider-

DISEASES OF UNCERTAIN ORIGIN 345

mal ceils contain the alga, which spreads over the leaf,
blackening and killing it.

Karsten, Ann. Jard. Bot. Buiten., vol. x., i pi. (1891).

Cephaleurus minus, Karsten, destroys the leaves of
Zizyphus jujuba in Java.
Karsten, I.e.

DISEASES OF UNCERTAIN ORIGIN
(Rhizoctinia violacea, Tul.)

This remarkable fungous parasite, the fruit of which is
not yet known with certainty, is too well known as being
most destructive to saffron (Crocus sativus). The roots
of many other plants are also attacked, including beet-
root, potato, lucerne, carrot, asparagus; also many wild
plants. The tubers or roots are invested by a more or
less dense violet or brownish mycelium, which gives off
violet rhizomorphs that anastomose irregularly, and traverse
the soil, attacking adjacent roots. By this method the dis-
ease extends rapidly from a diseased centre, unless very
prompt measures are adopted. Two forms of sclerotia
are also developed, one kind being often as large as a
hazel-nut, and minutely velvety, the other small, glabrous,
and often densely crowded, resembling the perithecia of
some Rosellinia in general appearance.

An ascigerous form of fruit — Leptosphaeria rirtinans,
Sacc. — found on dead roots of lucerne (Medicago sativd)
killed by the Rhizoctinia, may prove to be the perfect form
of fruit, but this point is as yet undecided.

PREVENTIVE MEANS. — If the disease appears, the area
should be isolated by a trench, throwing the removed soil

346 PLANT DISEASES

into the diseased part, and all plants included should be
carefully removed and burned. When a field has once
become thoroughly infested, it has been proved that after
an interval of twenty years saffron has been attacked at
once, the fungus having lived in the meantime on the roots
of various weeds.

Cereals which are not attacked by the Rhizoctinia should
be sown on infected ground, and all weeds should be kept
flown ; by these means alone can the fungus be destroyed.

Prillieux, Malad. des Plant es Agric., vol. ii. p. 144, figs.

COTTON ROOT-ROT

( Oz o n in m a u ricom u m )

Bulletin No. 7 of the Texas Agricultural Experimental
Station is devoted to an account of the above disease.

Ozonium was by the older mycologists considered as a
true genus of Fungi; it is now known to consist only of
sterile mycelium, usually of a brown or orange colour.
Opinion differs as to the perfect or fruiting condition of
Ozonium mycelium, which is probably a name covering
the mycelium of many distinct species. The cotton rot
has not yet been connected with any fruiting stage. It
attacks the roots, more especially the taproot, which is
surrounded by a weft of brown strands of mycelium.
When this stage has been reached, the cotton plant wilts,
then blackens and dies. The disease travels in the soil,
spreading irregularly in all directions from the point first
attacked.

Numerous forest and orchard trees, excepting the genus
Pninus, also suffer from root-rot caused by this fungus, as
do also the tubers of the sweet potato. Wet seasons, and

THE PEACH ROSETTE 347

especially rain followed by heat, favour the spread of the
disease, which is always worst on badly drained land.

PREVENTIVE MEANS. — Rotation of crops appears to be
the only known means of holding the pest in check.
Members of the grass family should be used as the alter-
nating crop, as these are not attacked by the fungus.

THE PEACH ROSETTE

A peculiar and very destructive disease attacking peach,
plum, and almond trees is described by Dr. Erwin F.
Smith as being very prevalent in Georgia. It agrees in
some important points with the disease known as peach
yellows, which has been investigated by the same author,
but differs in the following particulars, which may be con-
sidered as furnishing the characteristics of peach rosette : —

(1) The entire tree is more apt to be attacked all at
once, and the disease is more quickly fatal. Trees often
die the first year, and I have not heard of any cases living
beyond the second season. What corresponds to the first
stage of yellows seems to be wanting.

(2) On the parts attacked many obscure buds and all
or most of the winter buds push into diseased growths
suddenly in early spring. The primary shoot-axes grow
only an inch or two, but send out many short branches.
This gives to each growth a compact, tufted form, and to
the affected tree a very peculiar appearance, unlike any-
thing heretofore described, and much resembling the work
of insects. These stunted, green or yellowish rosettes often
form the only foliage of large trees, projecting from the
ends of long, naked twigs like leafy galls, or like house
leeks tied to the ends of sticks.

348 PLANT DISEASES

(3) The lower leaves on these tufts or rosettes roll and
curl, turn yellow, dry up at the ends and edges, and fall
early. They begin to drop before midsummer, and a
slight jar shakes them off by the hundred.

(4) On the trunk and base of the main limbs it is rare
to find anything more than rosettes, and often these are
also wanting, the diseased growths being confined to the
extremities of the branches.

(5) Diseased trees seldom bear fruit of any sort.

The following is Dr. Smith's summary : — The Scolytus
rugulosus does not cause this disease, nor do I think it due
to any other insect Whatever be its cause, the disease is
evidently increasing, and peach-growers should be on the
alert to destroy it as soon as it appears. The affected trees
should be dug out and burned as soon as discovered. The
contagious nature of the disease is now beyond dispute,
and it is not wise to let them remain a single day.

Smith, Journ. MycoL, vol. vi. p. 143, pi. viii.-xiii. (1891).

SLIME-FLUX

Weeping wounds, the liquid portion of which consists
of various micro-organisms mixed with water, forming a
glairy, repulsive mixture trickling down the trunk, are not
uncommon on many fruit and forest trees. Such represent
the ' Schleimfluss ' of the Germans, and the ' Ecoulement
blanc, rouge, musque,' etc., of the French. There is at
present a difference of opinion as to whether such outflows
originate the disintegration of tissue at the point from which
the mucus originates, or otherwise.

L'ecoulement blanc, viscid and alcoholic, is frequent on
oaks, but occurs also on other trees. It is the result of the
fermentation of all the elements of bark and cortex, down

PHYCOMYCETES 349

to the cambium zone, the agents in these pathological pro-
cesses being Endomyces magnusii, Ludw. ; Saccharomyces
ludwigii, Hansen ; and Leuconostoc lagerheimi, Ludwig.

A very full abstract of all that has been done in this
particular branch of vegetable pathology, accompanied by
copious references, is contained in Revue Mycologiquey
1896, by Professor Ludwig.

FUNGI
PHYCOMYCETES

Vegetative mycelium not forming a compact mass, but
ramifying in the living tissues of plants or animals, rarely
saprophytic. Asexual mode of reproduction by conidia
produced on the surface of the host, which on germination
produce zoospores or germ-tubes. Sexual reproduction by
zygospores or oospores, produced in the matrix, which
germinate only after a period of rest.

Chytridiaceae. — Parasitic on aquatic or aerial plants or
animals. Mycelium absent or very rudimentary ; asexual
reproduction by zoospores ; sexual reproduction by con-
jugation.

Olpidium, A. Braun. — Vegetative condition passive
naked protoplasm, the product of one spore. This becomes
enclosed in a thin cellulose wall, and forms the zoosporan-
gium, the uniciliate swarmspores escaping through a beak,
or the wall becomes very thick, and a resting-spore is
formed, which gives origin to zoospores. Sexual reproduc-
tion absent.

Parasitic in living cells of plants or animals.

Olpidium brassicae, Dang., Ann. Sri. Nat., 1886, p. 327
(Chytridium brassicae, Wor., Prings. Jahrb., vol. xi. p. 557).

35° PLANT DISEASES

Sporangia scattered, or several in a cell, globose, with
a thin, colourless wall and a long, slender tube, which
often passes through four or five layers of cells to reach
the surface of the host. Swarmspores globose, oneciliate,
with a glistening oildrop, and a vacuole. Resting-spores
colourless or yellowish, solitary or clustered, thick-walled,
warted. Germination unknown.

Saprolegniaceae. — Asexual reproduction by zoospores
formed in zoosporangia borne on the hyphae ; sexual
reproduction by antheridia and oospheres, producing
oospores.

Pythium, Pringsh. — Mycelium parasitic in living plants,
intra- and intercellular; zoosporangia usually terminal,
wall thin ; zoospores always naked; resting conidia inter-
stitial or terminal, often produced in large numbers ;
oogonia monosporous ; wall of oospore colourless, smooth
or ornamented.

Pythium de baryanum, Hesse, Ueber Pythium, etc.,
Hallenser Dissertat^ 1874. — Mycelium branched, septa
rare ; resting conidia spherical, thin-walled, terminating
short branches, or interstitial, 20-25 P diam. Zoospo-
rangia globose or broadly elliptical, often shortly papillate,
terminal or intercalary ; oogonia globose, membrane not
perforated; oospores globose, wall colourless, smooth, 15-
18 p diam., forming a mycelium, and not zoospores, on
germination. Antheridia clavate, on very short branches
immediately below the oogonia, or on distinct branches.

Pythium intermedium, De Bary, Bot. Ztg., 1881, p. 554,
tab. v., f. 14-16. — Conidia terminal, globose, in chains of
2-5, terminal one largest, 18-24 ^ diam., on germination

PHYCOMYCETES 351

producing either a germ-tube or zoospores. Sexual repro-
duction unknown.

Mucoraceae. — Mycelium and sporangiophores hyaline or
coloured ; asexual reproduction by spores and chlamydo-
spores ; sexually by zygospores. Aerial.

Rhizopus, Ehrh. — Vegetative hyphae creeping, producing
fasciculate rhizoids that penetrate the substratum; spor-
angiophores usually fasciculate, erect, coloured ; sporangia
globose, with a columella, many-spored, dark-coloured at
maturity. Zygospores formed in the substratum, con-
jugating branches straight; suspensors very short and
stout, without branchlets. Germination unknown.

Rhizopus nigricans, Ehrenb., Nova Acta A cad. Leop., x.
T, 198, tab. xi., f. 1-7. — Sporangiferous hyphae erect, in
fascicles of 3-10, springing from stoloniferous hyphae that
give off rhizoids at corresponding points ; .sporangia
globose, blackish-olive, granular, 100-300 //, diam., colum-
ella hemispherical ; spores broadly elliptical or globose,
grey, variable in size, 8-14 //, diam. Zygospore subglobose
or tun-shaped, 150-200 /*. Epispore brown, with rounded
warts.

Rhizopus necans, Massee, Kew Bulletin, 1897, p. 87,
i pi. — Sterile hyphae, creeping, forming a thin white
felt ; sporangiferous hyphae fasciculate, simple or forked,
coloured, about 2 mm. high, 20-25 f- thick, springing from
long, creeping stolons, which give off fasciculate rhizoids ;
sporangia globose, blackish-brown, smooth, about 250 p.
diam., columella large, subglobose; spores subglobose,
minutely striate, pale olive-brown, 5-6 /x ; zygosore tun-
shaped, 100-120 /A diam., blackish, covered with spinous
warts.

352 PLANT DISEASES

Peronosporaceae. — Conidiophores usually branched;
conidia generally producing zoospores ; sometimes directly
forming a germ-tube ; sexual reproduction by antheridia
and oosphores producing oospores.

Cystopus, Lev. — Conidia concatenate, chains vertical,
numerous, forming a sorus, which remains covered by the
epidermis of the host until the conidia are mature, and
then bursts through. Conidia all alike, producing zoo-
spores; or the terminal conidium thicker walled, giving
origin to a germ-tube, or sterile and protective in function.
Oospores globose, epispore usually ornamented.

Cystopus candidus, Lev., Ann. Sci. .Nat., ser. HI. vol.
viii. p. 371. — Sori white, shining, then powdery, often
large and confluent, conidia all similar, globose, smooth,
15-17 fj. diam. Oospore subglobose, 28-50 /*, epispore
yellowish-brown, with blunt warts, which sometimes pass
into short, crooked ridges.

Cystopus tragopogonis, Schroet, Krypt.-Flor. Schles.,
in. i. p. 234. — Sori white, globose or oblong, flat, often
concentrically arranged ; terminal conidium largest, thick-
walled, sterile, remainder shortly cylindrical, thin-walled,
with an equatorial thickened ring, 16-22 //,. Oospores
globose, 45-65 /*, brown, with large, hollow warts, which
are themselves minutely warted.

Phytophthora, De Bary. — Mycelium spreading in the
tissues of the host, haustoria few or wanting; gonidio-
phores generally sparingly branched, gonidia at first
terminal on the branches, then apparently lateral also,
owing to continuation of growth of apex of conidiophore
beyond the point of origin of the first conidium, elliptical,
apex papillate, usually producing zoogonidia on germination.
Oospores globose, epispore smooth, rather thin, brown.

PHYCOMYCETES 353

Phytophthora phase oli, Thaxter,^/. Gaz., vol. xiv. p. 273
(1889). — Mycelial hyphae branched, rarely penetrating the
cells of the host by irregular haustoria. Conidiophores
strongly swollen at their point of exit through the stomata,
arising singly, or one to several in a cluster; simple, or
once dichotomously branched, and once to several times
successively inflated below the apices; conidia oval or
elliptical, with truncate base and papillate apex, 35-50 x
20-24 p. Germination by zoospores, usually fifteen in
number, or rarely by a simple hypha of germination.
Oospores unknown.

Phytophthora infestans, De Bary, Journ. Bot., n. ser. vol.
v. p. 149 (1876). — Mycelium slender, haustoria absent;
conidiophores solitary, or in clusters of 2-5, emerging
through the stomata, simple or sparingly branched up-
wards, tapering upwards, above with scattered, swollen
portions, corresponding to the points of origin of conidia,
up to i mm. high, 10-12 p thick below, hyaline, forming
a very delicate mould on the leaf ; conidia lemon-shaped,
colourless, with a prominent papilla, 25-30 x 15-20 ft, pro-
curing on germination 6-16 swarmspores; oospores un-
known.

Phytophthora cactorum, Schroeter, Krypt. FL Schles.,
p. 236 = Phytophthora omnivora^ De Bary. — Hyphae vari-
ously branched, haustoria absent; conidiophores slender,
simple, or sparingly unilaterally branched, often nodulose
at intervals below the apex; conidia lemon-shaped,
50-60x35-40 /*, liberating on germination up to 50
zoospores ; oospore globose, smooth, yellowish-brown,
24-30 p diam., often conglomerated.

Plasmopara, Schroeter. — Mycelium stout, furnished with

354 PLANT DISEASES

small, entire, ovate haustoria. Conidiophores erect,
sparingly branched ; conidia generally papillate. Oospores
globose, epispore thin, smooth, brownish.

Plasmopara viticola, Berl. et De Toni, Sacc., SylL, vii.
p. 239 (\'&(&<£) — Peronospora viticola^ De Bary. — Mycelial
hyphae thick, often constricted and varicose, haustoria
minute, spherical ; conidiophores fasciculate, coming to
the surface through the stomata, slender, 250-850 yu, high,
branched near the apex ; primary branches 3-5, alternate,
secondary branches short, 3-4-furcate, ultimate branchlets
pointed, straight, short, usually 4, bearing the ovoid, smooth,
colourless, not papillate, very variable in size, smallest
8x12 /x, the largest 17X30 /x ; oospores subglobose,
30-35 [L diam., wall thin, brownish, smooth or slightly
wrinkled epispore, often very numerous in dead portions
of the host plant.

Bremia, Regel. — Mycelium with vesicular or clavate,
simple haustoria ; conidiophores repeatedly dichotomously
branched, tips of ultimate branchlets vesicular and bearing
several short, subulate sterigmata ; conidia sphaeroid,
papillate; oospores globose, minute, epispore yellowish-
brown, subrugulose.

Bremia lactucae, Regel, Bot. Ztg.^ 1843, p. 665, tab. iii.,
f. B. — Mycelium stout, often contorted ; haustoria clavate,
simple; conidiophores 2-6 times dichotomously, or some-
times trichotomously branched, ultimate branchlets inflated
at the tips, the inflated portion bearing several conical,
short spicules, each bearing a subglobose conidium with a
broad, depressed apical papilla, 16-23 /* j oospores globose
yellowish-brown, pellucid, epispore rugulose, 25-35 p.

Peronospora, Corda. — Mycelium generally bearing fill-

PHYCOMYCETES 355

form, branched haustoria; conidiophores solitary or
fasciculate, emerging through the stoma of the host,
dichotomously branched, ultimate branchlets often acute
and curved ; conidia ovate or elliptical, not papillate at
the apex, giving off a lateral germ-tube on germination ;
oospores globose or subglobose, epispore smooth or
variously ornamented.

Epispore of oo spore rugulose or netted.
Peronospora trichotoma, Massee, Journ. Linn. Soc.
(Bot?}, xxiv. 45, 2 figs. (1888). — Mycelium thick, haustoria
clavate; conidiophores fasciculate, 2-3 times trichoto-
mously divided ; conidia small, obovate, or subglobose,
i2Xio/x; oospore globose, epispore brown, with ridges
anastomosing to form an irregular network, 35-40 /*.

Peronospora parasitica, De Bary, Ann. Set. Nat, ser. iv.
vol. xx. p. no (1863). — Mycelium thick, much branched,
haustoria numerous, branched ; conidiophores stout,
flaccid, irregularly 5-8 times dichotomous or trichotomous,
branches always repeatedly bifurcate, the last two orders
of branches slender and curved ; conidia broadly elliptical,
20-22X16-20 n, apex very blunt, pure white; oospores
globose, 26-43, smooth or slightly rugulose, pale yellowish-
brown.

Peronospora effusa, Rabenh., Herb. Myc., Ed. i., 1880.
— Forming effused, greyish spots ; conidiophores fasci-
culate, emerging through the stomata, short, thick, 2-7
times dichotomously branched above, ultimate branch-
lets thick, shortly subulate, curved downwards ; conidia
elliptical, pedicellate, pale dingy lilac, 25-35x15-24 /A;
oospores globose, epispore clear brown, more or less
irregularly wrinkled, 25-40 /*.

356 PLANT DISEASES

Epispore of oospore smooth.

Peronospora schleideni, linger., Bot. Ztg.t 1847, p. 315.
— Forming greyish-lilac tufts ; conidiophores erect, 250-
400 /A high, branched alternately, or in a dichotomous
manner, ultimate and penultimate branches strongly
curved; conidia obovate, apex obtuse or subacute, pale
dingy violet, 44-52X22-25 /A; oospores broadly elliptical
or globose, epispore thin, smooth.

Peronospora trifoliorum, De Bary, Ann. Set. Nat., ser. iv.
vol. xx. p. 117 (1863). — Conidiophores 350-450 p high,
forming broadly effused tufts, equally or irregularly 6-7
times dichotomous, rarely trichotomous, primary branches
4-5 times dichotomous ; ultimate branchlets pointed,
slightly curved ; conidia ellipsoid, about 21 //, diam., wall,
pale violet; oospores globose, epispore thick, smooth,
brown, 25-34 p diam.

Peronospora schachtii, Fuckel, Symb. Myc., p. 71
(1869-70). — Forming dense grey tufts; conidiophores
erect, 6-8 times dichotomous, primary branches 2-5, short,
ultimate branchlets generally unequal, short, straight,
wide - spreading, obtuse ; conidia ovate, pale umber,
20-24X15-18 /A; oospores globose, wall thick, smooth.
Very closely allied to P. effusa.

Peronospora violae, De Bary, Ann. Sci. Nat., ser. iv.
vol. xx. p. 125.— Forming somewhat dense, clear, pale
violet tufts; hyphae rather short, about 300 //, 4-7 times
dichotomously branched, ultimate branchlets short, acute,
deflexed; conidia elliptical, blunt, shortly apiculate, aver-
aging 25 X 18 p, pale violet; oospore with a golden-brown
epispore.

Peronospora cubensis, Berk, and Curt.,/ourn. Linn. Soc

PHYCOMYCETES 357

(Bot.}, vol. x. p. 363 (1869). — Forming very delicate white
patches on the under surface of the leaf; conidiophores
repeatedly dichotomously branched, branches spreading,
ultimate branchlets acute, straight, spreading; conidia
hyaline, elliptical, 25-32X18-20 /*.

Peronospora hyoscyami, De Bary, Ann. Set. Nat., ser. iv.
vol. xx. p. 123. — Forming dirty greyish-violet tufts of the
under surface of the leaf, sometimes small, at others
effused over the greater portion of the surface; conidio-
phores 300-500 p. high, averaging 300 /*, 5-8 times
dichotomously branched near the apex, branches spread-
ing, ultimate ones very divergent, short, awl- shaped;
conidia small, elliptical, ends obtuse, pale dingy violet,
15-24X13-18^; oospore unknown.

Peronospora maydis, Raciborski, Ber. Deutschen Bot.
Gesell., xv. p. 475, 4 figs. (1897). — Conidia emerging
through the stomata, 0-3 mm. high, and up to 25 p thick,
with 1-3 main dichotomous branches, which are divided
at the tip into 3-6 conical, pointed branchlets, each bearing
a smooth, hyaline, globose conidium 15-18 /*- diam. ;
oospores globose, membrane smooth, 14-24 //, diam.

ASCOMYCETES

Spores produced in large mother-cells or asci ; asci
either naked, or more frequently produced within an
excipulum, or a perithecium ; perithecium either with a
distinct opening through which the asci escape at maturity,
or rupturing in an irregular manner, but never exposing
the disc or hymenium ; excipulum expanding and exposing
the hymenium at maturity.

Gvmnoasaceae. — Perithecium and excipulum absent,

358 PLANT DISEASES

hence the asci are naked, and almost free on the surface of
the host, i-4-8-spored, the asci frequently becoming crowded
with myriads of secondary spores produced by germina-
tion of the ascospores within the ascus ; paraphyses rare.

Exoascus, Fuckel. — Mycelium perennial in the host-
plant, in some species much reduced, and located between
the cuticle and the epidermis, in others more abundant,
intercellular in the tissues below the epidermis, and causing
malformations, as 'witches' brooms/ etc. Asci formed
in a series below the cuticle through which they emerge
to the surface at maturity, sometimes furnished with a
stem-cell which is cut off from the ascus by a septum ;
stem-cell or base of ascus usually penetrating between the
epidermal cells of the host. The asci at first contain 8
spores, but these often produce secondary spores of small
size which completely fill the ascus.

Exoascus deformans, Fuckel, Symb. Myc., 1869, p. 252.
— Asci cylindrical, apex rounded, 35-40X9-10 /*, stem-cell
6-8 X 6-9 /*, base somewhat pointed, and penetrating between
the epidermal cells.

Exoascus pruni, Fuckel, Enum. Fung. Nassoviae^ 1861,
p. 29, fig. 26. — The asci are 40-55x8-15 //,, stem-cell
10-16 /x, high, and about 5 //. broad at the base, which is
seated upon the epidermal cells, but not penetrating be-
tween them ; spores averaging 4-5 /x, diam.

Exoascus cerasi, Sadeb., Jahrb. der Hamburgischen
Wissensch. Anstalten, x. 2, 48 (1893). — Asci slender, clavate,
apex rounded, 30-50x7-10 //,, stem-cell 10-16x5-8 /*,
occasionally only about 3-5 p thick ; spores 6-9 X 5-7 /*.

ASCOMYCETES 359

Exoascus amentorum, Sadeb., Sitz.-Ber. d. Ges.f. Bot.
z. Hamburg, iv., 1888, p. 90. — Asci subcylindrical, base
more or less pointed, often immersed for one-third of its
length between the epidermal cells, 40-45 X 10 p, stem-cell
absent ; ascospores usually 8, 5 /x diam.

Exoascus turgidus, Sadeb., Jahrb. der Hamburgischen
Wissensch. Anstalten, x. 2, 59 (1893). — Asci 46-50 //- long,
apex rounded or more or less narrowed, widening below to
about 15 /x wide; stem-cell conical, up to 30 \L long
the pointed end passing between the cells of the host.

Taphrina, Fries. — Mycelium not perennial in the host
plant. Asci as in Exoascus, but the original 8 ascospores
produce quite early a large number of secondary spores,
consequently the ascus is crowded with minute spores as
soon as mature.

Taphrina bullata, Sadeb., Jahrb. der Hamburgischen
Wissensch. Anstalten, viii. 29, tab. 4, f. 4 (1890). — Asci
36-40 x 8-9 /x, stem-cell 10-15 X 8-9 fo not entering between
the epidermal cells, and not narrowed at the point;
ascospores 5 /x diam.

Taphrina sadebeckii, Johans., Ofvers. af K. Vet.-Akad.
Fork., 1885, p. 38. — Asci varying in length between 41-55 /"•,
and up to 15 /x broad, stem-cell 18-22 /x high, and fairly
thick, base rounded and but little, if at all, passing between
the epidermal cells ; ascospores 6 /u. diam., secondary
conidia more frequently present in the asci.

Taphrina ulmi, Johans., Ofvers. af K. Vet.-Akad. Forh.,
1885. — Asci very variable, for the most part short, cylin-
drical, apex rounded, 12-20x8-10 /x, stem-cell 3-6 /x high,
and 15-17 /x broad ; ascospores 3-5 /x diam.

Taphrina johansonii, Sadeb.,yh;^r^. der Hamburgischen

360 PLANT DISEASES

Wissensch. Anstalten, x., 2, 74 (1893). — Asd subclavate,
apex mostly rounded, 92-105 //, long, 16-25 /* thick at the
free part, portion between the epidermal cells 30-50 /x long,
base about 8 //, wide ; ascospores about 4 ^ diam.

Taphrina aurea, Fries, Obs. Myc., pt. i. p. 217 (1815).—
Asci very variable, sometimes slender and deeply sunk
in the leaf, 80-112 x 20-2 7 p; others are stouter, rounded
below, and entering but little between the epidermal cells,
measuring 80 x 30-40 p ; ascospores about 4 p diam.

Perisporiaceae. — Perithecia distinct, not produced on a
stroma, coriaceous or subcarbonaceous, not provided with
a distinct mouth, hence splitting irregularly to allow of the
escape of the asci ; mycelium superficial.

Microsphaera, Lev. — Perithecia containing many asci;
asci ovoid or oblong, 4-8 spored ; appendages branched at
the tip.

Microsphaera grossulariae, Lev., Ann. Set. Nat., 1851,
vol. xv. p. 1 60, tab. 9, f. 25. — Mycelium cobweblike,
greyish-white, on both surfaces of leaves; perithecia
scattered, 75-120 /*, appendages 10-20, once to twice as
long as diameter of perithecium, 4-6 times dichotomously
forked at the tips ; asci 3-5, ovoid ; spores 4-6, variable in
size, 15-30 p long.

Uncinula, Lev. — Perithecium containing several asci,
which are 2-8-spored ; appendages free from the mycelium,
curled at the undivided tips.

Uncinula spiralis, Berk., Crypt. Bot., p. 268, f. 64.—
Mycelium arachnoid, amphigenous, often evanescent;
perithecia minute, scattered, globose, blackish-brown,
appendages 10-20, variable in length, septate, occasionally
forked, tips loosely and spirally twisted, basal portion

ASCOMYCETES 361

coloured; asci ovate, pedicellate; spores 4-6, elliptical,
ends rounded, 20x8-10 /x.

Oidium stage ( = Oidium tuckeri).

Phyllactinia, Lev. — Perithecia globoso-depressed, con-
taining many asci, large, appendiculate, seated on arach-
noid mycelium ; asci 2-4-spored ; appendages acicular,
straight, radiating, base inflated into a vesicle.

Phyllactinia suffulta, Sacc., Mich., ii. p. 50. — Amphi-
genous or often most abundant on the under surface of
leaves, cobweblike, often evanescent ; perithecia scattered,
hemispherical, at length depressed, large; asci 4-20, ovate,
pedicellate, 80x50 /x, 2, seldom 3-4, spored, spores ovate,
variable in size, 40-52X22-25 /x.

Sphaerotheca, Lev. — Perithecia containing one ascus
only; ascus subglobose, octosporous; spores elliptical,
continuous, hyaline ; appendages of the perithecium
filamentous, tips not branched, mixed with the mycelium.

Sphaerotheca pannosa, Lev., Ann. Sci.Nat., 1851, vol. xv.
p. 138, pi. 6, f. 8. — Mycelium cottony then densely felted,
white, then tinged ochraceous, persistent; perithecia
minute, globose, scattered ; appendages, floccose, hyaline,
short; asci subglobose; spores 8, elliptical, 22-25 X
13-16 p.

Conidia in chains, terminal one the oldest, elliptical,
hyaline, 20-30 X 13-16 p.

Sphaerotheca castagnei, Lev., A?in. Sci. Nat., 1851,
vol. xv. p. 139, pi. 6, f. 9, 10. — Forming a white, cobweb-
like, often evanescent mycelium on both surfaces of leaves
or on inflorescence ; perithecia scattered, spherical, minute;
appendages numerous, short, brownish appendages with

362 PLANT DISEASES

flexuous tips, mixed with the mycelium; asci globose or
broadly ovate, 55-68x42-54 /x; spores up to 8, broadly
elliptic, hyaline, 15-20X12-15 /x.

Sphaerotheca mors-uvae, Berk, and Curt, Grev., iv.
p. 158. — Mycelium dense, thickish, margin white, centre
brownish ; perithecia minute, closely gregarious, black,
globoso-depressed, rugose, left prominent by the collapsing
mycelium, spores 15 /A long.

Erysiphe, Hedw. — Perithecia superficial, spherical or
hemispherical, submembranaceous, yellow then blackish;
appendages simple or vaguely branched, never dichotomous,
intermixed with the mycelium, often undifferentiated or
absent; asci, many in a perithecium ; spores hyaline;
conidia Oidium erysiphoides.

Erysiphe communis, Fries, Summa Veg. Scand., p. 406.
— Mycelium effused, arachnoid, persistent, or evanescent,
on both surfaces of the leaf; haustoria lobed ; perithecia
minute, scattered, or gregarious; appendages short; asci
subglobose, 4-8-spored, 4-8 in a perithecium, no X 72-
80 /x; spores elliptical, 40-42, 20-22 p.

Asterula, Sacc. — Perithecia seated on blackish, radiating,
subsuperficial mycelium, lenticular or globoso-depressed,
almost mouthless, membranaceous ; asci generally octo-
sporous ; spores continuous, hyaline.

Asterula beijerinckii, Sacc., SylL, ix. 376 = Ascospora
beijerinckii, Vuill., Journ. de Bot.^ 1888, p. 255 figs. —
Mycelium plentiful, crustaceous ; perithecia globoso-
depressed ; mouth very minute or absent, 100-130 /x diam.,
black, carbonaceous, erumpent ; asci numerous (up to 40),
obovate, then cylindrical, 110X20 /A; spores elliptical,
ends obtuse, continuous, hyaline, 17X5-7 /*•

ASCOMYCETES 363

Pycnidia = Phyllosticta beijerinckii^ Vtiill. — Perithecia
globose, pierced, surrounded by septate hyphae, 150 \i
diam., conidia elliptical, 6x5^, extended in a viscid
tendril. Considered by Vuillemin as the higher form of
Coryneum beyerinckii.

Dimerosporium, Fuckel. — Perithecia superficial, mouth-
less, membranaceo-carbonaceous ; asci short, 8-spored ;
spores i -septate, hyaline or fuscous ; mycelium copious,
black, subcrustaceous, often bearing conidia.

Dimerosporium mangiferum, Sacc., SylL, i. p. $$=Cap-
nodium mangiferum, Cke. and Broome, Grev. iv. p. 117. —
Effused, sometimes almost covering the entire surface of
the leaf, amphigenous, velvety, intense black ; perithecia
narrowly ovate, elongated; asci broadly piriform, 48-50 x
30 /u, ; spores 8, hyaline, i-septate, elliptical, slightly con-
stricted at the septum, 12-15 x 5-6 /*.

Meliola, Fries. — Perithecia seated on superficial spots
or effused patches of black, radiating mycelium, globose,
mouthless, membranaceous, often surrounded by specialised
bristles or appendages ; asci often short and broad, 2-8-
spored ; spores typically oblong, 2-5-septate, fuscous ;
sometimes truly continuous or muriform, hyaline, or
fuscous.

Meliola penzigii, Sacc., Sy/t., i. 70. — Mycelium crus-
taceous, effused, black, readily peeling off ; perithecia
subglobose, superficial, glabrous, springing from threads
of mycelium, umbilicate, black, 150-160 p diam. ; asci
obovate, apex rounded, sessile, 8-spored ; spores distichous
or irregularly grouped, ovate-oblong, 3-septate with one or
more vertical septa also, constricted, 11-12X4-5 /*, hyaline

364 PLANT DISEASES

then tinged brown. Secondary fruit, Coniothecium Hetero-
botrys, Chaetophoma, Capnodium, etc.

Capnodium, Mont. — Mycelium effused, black, spreading
over leaves, branches, and fruit ; perithecia rather fleshy
or carbonaceous, simple or branched, vertically elongated,
often torn at the mouth ; asci obovoid or oblong ; spores 8,
ovoid-oblong, typically 3-4-septate, sometimes muriform,
fuscous.

Capnodium citricolum, M 'Alpine, Proc. Linn. Soc. N.S.
Wales, 1896, pt. 4, pi. xxiii.-xxxiv. — Forming black,
sootlike incrustations, peeling off as a thin membrane,
often covering entire surface of leaf. Perithecia intermixed
with spermogonia, antennaria, ceratopycnidia, and pycnidia,
sea-green to sage-green appearing black, oblong to oval
or variously shaped, rounded and smooth at free end, with
netlike surface, 112-250X52-112 //; asci cylindric-clavate,
subsessile, apex rounded, 8-6 or 4-spored, 70-80 x 19-20 /*;
spores brown, oblong, sometimes a little fusoid, generally
obtuse at both ends, constricted about the middle, 5-6-
septate, often with longitudinal or oblique septa, arranged
mostly in two ranks, but occasionally in three, averaging
21-24x8-9*5 p; paraphyses hyaline, elongate-clavate, as
long as the asci, 9*5 /* broad towards apex.

Torula, Coniothecium, and Heterobotrys stages occur.

Sphaeriaceae. — Perithecia distinct or produced in
numbers in the substance of a stroma, membranaceous,
coriaceous, or carbonaceous, distinct from the substance
of the stroma (when the latter is present), blackish, fur-
nished with a distinct mouth through which the ascospores
escape.

ASCOMYCETES 3^5

Spores continuous, hyaline,

Trichosphaeria, Fckl., Symb. Myc.> p. 144. — Perithecia
subglobose, superficial, sparsely or densely pilose, some-
times seated on a byssus ; asci oblong or cylindrical, 8-
spored ; spores continuous, ovate, oblong-ovate, or sub-
cylindrical, very rarely appendiculate, always hyaline.

Trichosphaeria sacchari, Massee, Ann. Bot., 1893, p.
515, pi. xxvii. — Perithecia broadly ovate, blackish-
brown, sparsely clothed with long, dark, rigid hairs; asci
cylindrical ; spores 8, obliquely i-seriate, hyaline, con-
tinuous, elliptic-oblong, 8-9 X 4 p ', paraphyses absent.

Melanconium stage ; oozing out to the surface of dying
canes in the form of black, curved tendrils ; conidia pro-
duced in conceptacles situated in a stroma formed under
the epidermis, i-septate, pale-brown, cylindrical, straight or
very slightly curved, 14-15 X 3*5-4 /*.

Macroconidia. — Forming an intensely black, velvety layer,
lining cracks and cavities in decaying canes ; conidia in
chains originating within the ruptured apex of a hypha ;
terminal conidium globose, 20-25 //. diam., the others barrel-
shaped, 18-20X12 /*, blackish-brown.

Muroconidia. — Similar in origin and structure to the
Macroconidia, but smaller ; growing on the diseased surface
of the cane, and forming black, velvety patches.

G-uignardia, Viala and Ravaz. — Perithecia innate, lenti-
cular, usually with a projecting mouth, membranaceous ;
asci 8-spored, usually subclavate ; spores elongated, con-
tinuous, hyaline ; paraphyses absent.

Guignardia bidwellii, Viala and Ravaz, Bull. Soc. Myc.
France, viii. p. 63 (1892) — Spermogonia (= Haemaspora

366 PLANT DISEASES

ampelicida Engelm.). — Conceptacles innate, subglobose,
mouth piercing the matrix ; spermatia hyaline, cylindrical,
slightly constricted at the centre, 1*5 X '5 //•, borne on very
slender conidiophores. Germination unknown.

Pycnidia {=Phoma iivicola^ Berk, and Curtis). — Con-
ceptacles indistinguishable from those of the spermogonia ;
conidia hyaline, elliptical, variable in size, 6-9 x 3-4 ^.

Perithecia. — These are the conceptacles of the Phoma
stage, which produce asci the following season ; asci
clavate, obtuse, narrowed below, straight or slightly curved,
65-70X10-11 p; spores 8, continuous, hyaline, slightly
obovate, 12-15x6-7 /A; paraphyses absent.

Spores \-septate, hyaline.

Sphaerella, Ces. and De Not. — Perithecia membran-
aceous, subglobose or depressed, covered by the epidermis
or erumpent, mouth indented or shortly papillate; asci
8-spored ; spores elongated, i-septate hyaline, or very
slightly tinged ; paraphyses absent.

Sphaerella fragariae, Sacc., *$>//., ii. p. 505. — Perithecia
gregarious, often circinating, globose, black, innato-erump-
ent, seated on pale spots surrounded by a purple ring
previously occupied by the conidial form 90-130 fj. diam. ;
asci oblong, 8-spored, 40 //, long; spores i-septate, slightly
constricted, hyaline, 15x3-4 /*.

Conidia (Ramularia tulasnei^ Tul.). — Conidiophores
springing in tufts from the whitish, bordered spots; conidia
narrowly elliptic-oblong, continuous, or i-3-septate, variable
in size, 20-50X2-5-4 /*, hyaline.

Spermogonia. — Conceptacles resembling the perithecia in
form, rather smaller, and mixed with the latter, containing
myriads of ovoid spermatia about 3 /*. long.

ASCOMYCETES 367

Sphaerella tabifica, Prill, and Dell., Bull. Soc. Myc.
France, vii. 23, figs (1891). — Perithecia rotund, brown,
erumpent, mouth papillate, 150 p diam. ; asci oblong-
clavate, obtuse, stipitate, 60-12 p ; spores hyaline, 2-celled,
upper cell ovate-rotund, lower narrower, slightly attenuated,
septum below the middle, constricted, 21 x T5 f*> 2-seriate;
paraphyses absent.

Conidial stage (Phyllosticta tabifica^ Prill, and Dell.,
Phoma betae, Frank). — Conceptacles subglobose, pierced
by a pore at the summit; conidia escaping in a muci-
laginous tendril, elliptical, hyaline, 5-7 X 3-4 p.

Gnomonia, Ces. and De Not. — Perithecia covered or
erumpent, glabrous, submembranaceous, often scattered,
ostiolum more or less elongated, cylindrical, central, or
lateral ; asci 4-8-spored, tunic often perforated at the
apex ; spores elongated, i -septate, hyaline ; paraphyses
usually absent.

Gnomonia erythrostoma, Auersw., Myc. Eur. Pyren.^ p.
26, f. 127. — Perithecia innate, erumpent, shortly rostellate,
texture parenchymatous, rufescent ; asci cylindrical, shortly
stipitate, apex obtuse, apical lumen bifoveolate, 8-spored,
100-110X12-15 p-} spores distichous, cylindric-oblong,
rounded at both ends, spuriously i-septate below the
middle, not constricted, 4-guttulate, hyaline, furnished with
a small curved appendage which soon disappears, 18x5-6
fj,-, paraphyses absent. Fuckel describes spermagonia as
follows : — Resembling Septoria. Perithecia ? subsuperficial,
gregarious on large, discoloured spots ; spermatia filiform,
continuous, curved, elongated, hyaline.

Dipaorthe, Nits. — Perithecia membranaceous or subcoria-
ceous, often greyish within, most frequently furnished with

368 PLANT DISEASES

a filiform, long ostiolum, rarely short ; asci fusoid, 8-spored.
Spores fusoid or subellipsoid, i -septate, generally constricted
at the septum, hyaline, with or without appendages.

Sub.-Gen. Chorostate, Sacc. — Perithecia aggregated in
clusters in a Valsoid manner.

Diaporthe (Chorostate) taleola, Sacc., Fung. Yen., ser. iv.
p. 12. — Aglaospora taleola, Tul. — Stroma cortical, perithecia
numerous, small, crowded in the centre, disc white, ostiola
punctiform-immersed, smooth; asci cylindrical, 8-spored,
152X14 fS spores obliquely i-seriate, oblong-ovate, ends
obtuse, i-septate, constricted, hyaline, with i slender ap-
pendage at each end, and 3 appendages springing from the
median septum, 18-24 x 7-9 /*.

Spores 2-111 any-septate, hyaline.

Calospora, Sacc. — Stroma immersed in the bark, valsoid,
pustulate ; asci typically 8-spored ; spores oblong or fusoid,
2-pluriseptate, hyaline, with or without appendages ; para-
physes present.

Calospora vanillae, Massee, Kew Bulletin, 1892, p. m,
i pi. — Perithecia subglobose, narrowed above into a neck ;
asci cylindric-clavate, 90-100X12-14 /^; 8-spored; spores
elliptical, 3-septate, hyaline, 15-16x5^; paraphyses slender.
Cytospora form ; perithecia globose, conidia hyaline,
elliptical, continuous, 14-16 x 6-7 //. HainesiatQim. Dull
red or amber-coloured, gelatinous pustules, conidia sub-
hyaline, continuous, 9-10X3*5-4 /*.

Herpotricha, Fckl. — Perithecia carbonaceous, globose,
clothed with long, crisped, creeping hairs, vertex flattened,
subglabrous, discoloured, mouth minute, papillate ; asci
oblong, stipitate, 8-spored ; paraphyses usually present ;

ASCOMYCETES 369

spores subdistichous, ovate-oblong, or fusoid, i- then many-
septate, both ends sometimes papiilately-apiculate, hyaline.

Herpotricha nigra, Hartig, Hedw., 1888, p. 13. — My-
celium blackish-brown, widely effused, slender, furnished
with haustoria, attacking living leaves which it kills;
perithecia subglobose, black, 0*3 mm. diam , clothed with
long deflexed hairs towards the base; asci 76-100X12 /A;
spores distichous, i- soon 3-septate, constricted at the
middle, 4-guttulate.

Acanthostigma, De Not., Sfer. ItaL, p. 85. — Perithecia
free, spherical, fragile, clothed with setae or hairs, papillate,
with a perforate mouth ; asci 8-spored ; spores elongate-
fusoid, 1-5 septate, hyaline ; paraphyses present in some,
absent in other species.

Acanthostigma parasiticum, Sacc., Sy/t., vii. 855.—
Perithecia subglobose, minute, mouth distinct, the upper
portion with rigid, divergent bristles, o'i-Q'25 mm. diam.,
and with the bristles 0*7 mm. diam. ; asci 50 n long, soon
disappearing ; spores fusoid, straight, or curved, smoky-grey,
15-20 p long, soon 2-3-septate.

Spores continuous, coloured.

Rosellinia, De Not. — Perithecia subsuperficial, sub-
globose, papillate, subcarbonaceous, black, glabrous, or
hairy, or seated on a byssus ; asci cylindric or cylindric-
clavate, 8-spored, spores continuous, broadly ovate or
elongated and cymbiform, brown, with or without append-
ages ; paraphyses present.

Rosellinia quercina, Hartig, Baumkrankh., p. 100, pi.
8, 9. — Perithecia scattered or subgregarious, seated on a
black byssus or subiculum, large, black, globose, obtusely

2 A

370 PLANT DISEASES

papillate, about i mm. diam., smooth ; asci cylindrical or
subclavate, base narrowed, 160-170x8-10 /*, 8-spored;
spores obliquely i-seriate, fusoid, guttate, both ends acute,
brown, 28 x 6-7 p.

Kosellinia ligniaria, Nits., Fuckel's Symb. Myc., 150 (1869-
70). — Perithecia gregarious, globoso-conic, superficial, black,
sparingly covered with minute hairs, J mm. diam. ; asci
cylindrical, stipitate, 8-spored, 80-96x10-12 //- ; spores
obliquely i-seriate, ends obtuse, blackish-brown, continuous,
16X87*.

Rosellinia necatrix, l&er\.=Dematophora necatrix^ Hartig.
— Perithecia densely gregarious, seated on a byssus or
subiculum, obovate, blackish, nearly 2 mm. diam., surrounded
at the base by fascicles of conidiophores ; asci cylindrical,
8-spored ; spores fusiform, often inaequilateral, continuous,
brown, 40 X 7 /* ; paraphyses filiform ; conidiophores spring-
ing from small black sclerotia, fasciculate, branched; conidia
elliptical, hyaline, 2-3* ^ long ; pycnidia springing from
sclerotia, black, subglobose; stylospores hyaline, elliptical,
continuous, or 1-3 celled, averaging 25X8 /x.

Sosellinia radiciperda, Massee, Kew BulL> 1896, p. i,
i pi. — Ascophores densely gregarious, seated on a black,
velvety byssus, globoso-depressed,mamillate, black, glabrous,
large; asci cylindrical, apex truncate; spores 8, i-seriate,
elliptic-fusiform, slightly inaequilateral, continuous, brown,
40-45X12 /x; paraphyses filiform; pycnidia globoso-
depressed, sparingly pilose, black, stylospores elliptic-oblong,
continuous, hyaline, continuous, 7-8 X 4-5 ^ ; conidiophores
springing in fascicles from small black sclerotia, much
branched at the apex ; conidia terminal on the branchlets,
hyaline, continuous, elliptic-oblong, 7X4 ft.

ASCOMYCETES 371

Spores muriform.

Pleospora, Rabenh. — Perithecia scattered or subgre-
garious, immersed, or erumpent through the epidermis,
spherical, ostiolum generally papillate, glabrous, membran-
aceous, rarely hard (Sckropled} ; asci clavate, 4-8-spored ;
spores elongated, yellowish, or fuliginous, rarely hyaline
( Catharinid] ; conidia, pycnidia, and spermogonia some-
times present.

Pleospora gummipara, Oud., Hedw.^ 1883, p. 162. —
Perithecia formed in the neighbourhood of the pycnidia
and conidia, black, glabrous, globose, J-J mm. diam.,
membranaceous, sometimes bearing sessile Coryneum
conidia on the surface; asci 90 x 18-20 //, 8-spored; spores
biseriate, 3-septate, constricted at the septa, then becoming
muriform, dark brown, 24X12 ^ ; paraphyses absent;
pycnidia, conceptacles resembling the perithecia, conidia
brown, continuous, then transversely septate, finally muri-
form, about 7 p diam.

Conidia = Coryneum gummiparum, Oudem., Hedw., 1883,
p. 131. — Fruit clusters very minute, dotlike, black,
gregarious ; conidia springing from a brownish prosenchy-
matous cushion, oblong or oblong-ovate, pale smoky-olive,
3-septate, slightly constricted at the septa, 14x6^; conidio-
phores colourless, shorter than the conidia.

Hypocreaceae. — Perithecia free, or more or less immersed
in a somewhat soft, fleshy, waxy, or rarely a byssoid stroma,
somewhat fleshy, or waxy-membranaceous, generally reddish
(rarely bluish, olive-yellow, or pallid), never carbonaceous,
mouth distinct ; asci 4-8-many-spored, usually containing
8 spores ; secondary conditions of fruit frequent.

372 PLANT DISEASES

Claviceps, Tul. — Stroma stipitate, erect, capitate, spring-
ing from a sclerotium ; perithecia immersed in the stroma,
very slightly protruding ; asci cylindric-clavate ; spores
filiform, continuous, hyaline ; spermogonia and conidia
present in some species.

Claviceps purpurea, Tul., Ann. Set. Nat., 1853, vol. xx.
tab. 3. — Mycelium developing in the ovary of various
grasses and forming first a whitish, minutely velvety body
on the surface of the ovary, covered with conidiophores
bearing very minute conidia ( = Sphacelia segetum, Lev.).
Next the sclerotium increases in size and becomes horn-
shaped or cylindrical, slightly curved, purple-black, and
rugulose externally. After a period of rest the sclerotium
gives origin to one or several stipitate, subglobose, purplish,
warted stromata 2-4 mm. diam., stem often crooked, 1-3
cm. long ; asci narrow, 8-spored ; spores filiform, hyaline,
continuous, arranged in a parallel fascicle, 50-70 x i'5 /^.

Epichloe, Fries. — Stroma sessile, effused, girdling the
culm in grasses, bright-coloured or blackish, at first bear-
ing conidia ; perithecia immersed, mouth scarcely promi-
nent ; asci 8-spored ; spores filiform, almost as long as the
ascus, hyaline or tinged yellow, continuous or multiseptate,
in some species separating at the septa into numerous
cells, arranged in a parallel fascicle in the ascus.

Epichloe typhina, Tul., Fung. Carp.^ iii. p. 24. — Stroma
entirely encircling the culm of various grasses, up to 3
cm. long, at first whitish and producing ovoid, hyaline
conidia 4-5 X 3 fj< ; then yellow and finally tawny orange,
minutely granulose from the projecting mouths of the
perithecia ; asci cylindrical, slightly constricted just below

ASCOMYCETES 373

the truncate apex, 130-200x7-10 /*; spores filiform,
hyaline, very delicately multiseptate, I3o-i5ox 1-1*5 /*•

Nectria, Fries. — Perithecia distinct, caespitose, or scat-
tered, sometimes seated on a fleshy stroma that has pre-
viously borne conidia ; ostiolum usually papillate, fleshy, or
submembranaceous, soft, glabrous, downy, squamulose, or
byssoid, brightly coloured, usually red or orange; asci
cylindric-clavate, 8-spored; spores elongated, hyaline,
i-septate ; paraphyses absent or indistinct.

Nectria cinnabarina, Fr. — Perithecia caespitose, crowded
on a pulvinate hemispherical, fleshy pink stroma, which at
first bears minute, hyaline conidia, 6-8 Xi '5-2 p(=Tuber-
cularia vulgaris) ; perithecia spherical, corrugated, cinnabar,
then reddish-brown, mouth papillate; asci cylindric-sub-
clavate, apex slightly narrowed, 8-spored, 60-90x8-12 p;
spores i-2-seriate, oblong, ends obtuse, straight or slightly
curved, hyaline, i-septate, 14-16x5-7 /^.

Nectria ditissima, Tul., Carp., iii. p. 73, tab. 13, f. 1-4. —
Perithecia usually broadly effused in very dense clusters,
globose, obtuse, then papillate, polished, bright blood-red ;
asci cylindric-clavate, 82X8 /*, 8-spored ; spores ovate-
oblong, i-septate, hyaline, 14x5-6 /*.

Conidial form, Tubercularia crassostipitata, Fckl.,
conidia ovate-oblong, continuous, 6-8 X 3-4 /*.

Nectria cucurbitula, Fries, Summ. Veg. Scand.^ 388. —
Perithecia usually in numerous scattered, very dense
clusters, globose, polished, vermilion, shortly and obtusely
papillate, not collapsing; asci cylindrical, slightly con-
stricted below the apex, shortly stipitate, 8-spored, 100-
IIOX9-IO//-; spores i-seriate, oblong-biconoid, i-septate,
constricted at the septum, hyaline, 14-18x6-7 //.

374 PLANT DISEASES

Nectria ipomeae, Halst, Rep. N. Jersey. Agric. Expt.
St., 1891, p. 281, figs. — Perithecia in little clusters, conico-
globose, acutely papillate, verrucosely squamulose, red;
asci cylindric-clavate, 8-spored; spores hyaline, cylindric-
oblong, i-septate, slightly constricted at the septum.

A Fitsarium condition is present with this species.

Nectria pandani, Tul., Fung. Carpol., iii. p. 71 (as a foot-
note).— Perithecia crowded, globose-ovate, papillate, pallid ;
asci cylindrical , 80 x 6 /x ; spores monostichous, shortly
lanceolate, straight, 10X4 ft, i-septate.

Often accompanied by a conidial form scarcely differing
from Acrostalagmus tinnabarinus, except in its pale colour.
The Nectria springs from pustules of Melanconium pan-
dani, Lev., of which it is suspected as being the ascigerous
condition.

Nectria vandae, Wahrl., Orchideenwurzelpilze, p. n,
f. 20, 23, 24. — Perithecia solitary or 3-5 or more in a
cluster on a reddish, well-developed stroma, pear-shaped,
red, very furfuraceous, substance thickish, white near the
ostiolum ; asci 8-spored ; spores obliquely i-seriate, ellipti-
cal, 8-10 X 4*4 /A, i-septate, slightly constricted at the
septum, hyaline.

Conidia cylindrical, ends rounded, 20-30 x 3 '3-4*4 /A,
borne on long conidiophores, forming dense tufts.

Nectria goroshankiniana, Wahrl., Orchideenwurzelpilze,
p. n, f. 17, 22, 25. — Perithecia solitary or 3-5, rarely
more, in a cluster, seated on a reddish-brown, well-
developed stroma, ovoid, apex subacute, deep red,
squamulose; substance thin, deep-red; asci 8-spored;
spores obliquely i-seriate, lanceolate-elongate, i-septate,
slightly constricted at the septum, tinged brown, I2-I5X

ASCOMYCETES 375

4-5 ju, ; conidia same as in N. vandae, inserted in tufts at
the apex of the sporophore.

Polystigma, Pers. — Stroma rather fleshy, parenchy-
matous, effused, innate on the leaf, ochraceous, tawny, or
reddish ; perithecia immersed ; asci 8-spored ; spored ovoid
continuous ; spermogonia usually present.

Polystigma rubrum, D. C, Mem. Mus., p. 337, pi. 4,
f. 7. — Hypophyllous, suborbicular, reddish, then reddish-
brown, ostiola sunk ; asci clavate, 8-spored ; spores ovoid,
obtuse, straight, subhyaline, 10x6 /*.

Spermogonia (Libertella rubra, Bonor). — Spermatia fili-
form, curved, 30 /u long.

Dothidiaceae. — Compound, stroma pulvinate, effused,
or linear, coriaceous or carbonaceous (not fleshy), blackish
(not brightly coloured) ; perithecia or loculi confluent and
homogeneous with the substance of the stroma, but dis-
tinctly defined, mouth distinct ; asci 4-8-spored ; spores
often hyaline, rarely brownish ; secondary forms of fruit
common.

Plowrightea, Sacc. — Stroma convex-pulvinate, often
confluent, and form an extended crust, thickish, coriaceous,
becoming black ; asci elongated, 8-spored ; spores ovoid
or elliptical, i-septate, hyaline, or faintly tinged with
yellowish green ; conidia and pycnidia known in some
species.

'Plowrightia morbosa, Sacc., *$>//., ii. 638 (1883).—
Stromata caestipose, forming large, elongated, nodulose,
rigid, black incrustations on branches. Conidiophores
bearing ovoid olive conidia, about 16 /A long, first covering
young stromata with a blackish-olive velvety layer; peri-

376 PLANT DISEASES

thecia crowded, variable in form; asci cylindric-clavate,
110-150X16-18 fi ; spores obovate, hyaline, i-septate,
basal cell much the smaller of the two, 15-20x8-10 ^ •
pycnidia resembling the perithecia, containing elliptical,
pale yellow, 3-septate stylospores, 10-12x6-7 p-, sper-
mogonia also similar to perithecia, containing exceedingly
minute spermatia.

Plowrightia ribesia, Sacc., Syll., ii. p. 635 (1883).—
Stroma transversely erumpent, convex, black, minutely
granular with the ostiola, up to 2 mm. long ; loculi
occupying the periphery, minute; asci 85-100X12-14 /* ;
spores 8, distichous, elongato-fusoid, slightly curved, un-
equally i-septate, yellowish-white, 18-20x5-6 /A.

Hysteriaceae. — Ascophore erumpent, innate, or super-
ficial, elliptical or linear, or vertical and compressed,
carbonaceous or membranaceous, dehiscing by a long,
narrow slit, black or blackish-brown, disc not exposed at
maturity ; asci 4-8-spored ; spores hyaline or coloured,
continuous or septate ; paraphyses usually present.

Lophodermium, Chev. — Perithecia innate, elongated,
membranaceous, dehiscing by a longitudinal slit ; asci
clavate or cylindric-clavate, 8-spored ; spores hyaline,
filiform guttulate, almost as long as the ascus, arranged in
a parallel fascicle ; paraphyses filiform.

Lophodermium macrosporum, Rehm, Krypt.-Flora,
p. 45. — Apothecia black, elliptical, arranged on either side
of the nerve ; asci clavate, apex narrowed, 100X15-21 p;
spores needle-shaped, continuous, 75Xi'5/*j paraphyses
filiform, apex hooked.

Lophodermium nervisequum, Rehm, Krypt.-Flora,

ASCOMYCETES 377

p. 44. — Perithecia forming a single line on the nerve on
the under side of the leaf; spermogonia a year earlier on
the upper surface; asci clavate, apex narrowed, 70-100 x
15-20 p ; spores linear-clavate, continuous, 50-60 x 2-2*5 A* >
paraphyses hooked at the tips.

Lophodermium pinastri, Chev., Flor. Paris, i. 430. —
Perithecia scattered, many usually surrounded by a black
line, epiphyllous, innately immersed, elongated, black,
glabrous, finally longitudinally split, disc livid; asci
cylindric-clavate, apex narrowed, 8-spored, 115-165x14-
17 /A ; spores in a parallel fascicle, filiform, apex thickened,
guttulate, hyaline, ioo-i4oX i'5-2 /A; paraphyses slender,
tips curved.

Discomycetaceae. — Excipulum fleshy, rarely subcarbon-
aceous, clear-coloured, rarely blackish, glabrous, downy,
or hairy, closed at first, then expanding and exposing the
disc at maturity, sessile or stipitate, sometimes springing
from a sclerotium ; asci 4-8-rarely-many-spored ; spores
hyaline, rarely coloured, continuous or septate ; paraphyses
present.

Rhytisma, Fries. — Ascophores crowded on a thin,
broadly effused, black, crustlike stroma ; elongated, often
more or less wavy, finally gaping and exposing the pale
disc ; asci clavate, 8-spored ; spores linear, hyaline,
continuous, arranged in a parallel fascicle in the ascus ;
paraphyses slender, often curved at the tip.

Conidia are formed on the stroma before the ascospores
in some species. By some considered as belonging to the
Pyrenomycetae.

Rhytisma acerinum, Fries. — Stroma forming thin, black,
crustlike patches on living leaves, J-i in. broad; ascophores

378 PLANT DISEASES

appearing in the spring on fallen, dead leaves, elongated,
wavy, gaping, disc pale ; asci clavate ; spores needle-shaped,
about 60-80 X i '5-2 -5 //, ; paraphyses slender, curved at the
tip; conidia cylindrical, hyaline, straight, or curved,
6-9 X i /*.

Rhytisma punctatum, Fr. — Strom a black, broken up
into small detached pieces, seated on a yellow spot on
living leaves ; ascophores circular or elongated ; asci
clavate, tip narrowed ; spores 8, needle-shaped, apex blunt,
base pointed, arranged in a parallel bundle, 35-40 X 1*5-2 ft;
paraphyses slender ; conidia cylindrical, straight, hyaline,
5-6x1-5 j*.

Khytisma salicinum, Fries, Vet. Akad. HandL, 1819,
p. 104. — Stroma forming circular or irregular, thickish,
shining black patches on the upper surface of leaves ;
asci clavate, apex narrowed ; spores 8, needle-shaped,
pointed at both ends, curved, continuous, guttulate, hyaline,
65-95 X i'5-2'5 ft; paraphyses slender, tips wavy.

Pseudopeziza, Fckl. — Parasites or saprophytes ; asco-
phore erumpent, sessile, sometimes narrowed at the base,
glabrous, minute; asci narrowly clavate, apex usually
narrowed, 4-8 spored; spores hyaline, smooth, narrowly
elliptical or fusiform, continuous or i-septate; paraphyses
present.

Pseudopeziza trifolii, Fckl., Symb. Myc., p. 290. — Epi-
phyllous, sessile, gregarious, in small clusters on dark spots,
erumpent, soon plane, dingy yellow, glabrous, about J
mm. across; asci clavate, 8-spored, spores irregularly
2-seriate, hyaline, elliptic-oblong, or sometimes slightly
broader at the apex, 10-15x5-6 ft; paraphyses hyaline,
rather stout, sometimes branched.

ASCOMYCETES 379

Dasyscypha, Fries. — Ascophore minute, shortly stipitate
or sessile, closed at first, gradually expanding externally,
and the margin pilose or downy ; asci cylindric-clavate,
8-spored; spores irregularly 2-seriate, hyaline, smooth,
narrow, and elongated, continuous or i-septateat maturity;
paraphyses lanceolate or cylindrical, often longer than the
asci.

Dasyscypha calycina, Fuckel.— Caespitose, gregarious, or
scattered, narrowed into a short, stout, stemlike base, rather
fleshy, up to i line broad; disc orange-yellow; externally
white, villose; asci subcylindrical ; spores hyaline, elliptic-
fusiform, continuous, 18-25x6-8 /*; paraphyses slender,
cylindrical.

Sclerotinia, Fuckel. — Ascophore solitary or gregarious,
springing from a sclerotium, stipitate, at first closed,
gradually expanding until saucer-shaped or plane, glabrous,
brown ; asci narrowly cylindrical, 8-spored ; spores obliquely
i-seriate, hyaline, continuous, and smooth; paraphyses
slender.

Conidial form {—Botrytu and Afoniltd) often present;
ascophore absent in some species, the conidial form
absent in others.

* Ascigerous and conidial forms known.

Sclerotinia fuckeliana, Fuckel, Symb. Myc.t p. 320.—
Ascophores 1-3 springing from a small sclerotium, soon
plane, 0-5-3 mm. broad, yellowish-brown ; stem very slender,
5-10 mm. high; asci cylindric clavate, 130X12-13 /x;
spores elliptical, hyaline, 10-11x6-7 /*.

Conidial form ( — Botrytiscinerca, Pers.). — Sterile hyphae
creeping, fertile, erect, gregarious, simple or sparingly

380 PLANT DISEASES

branched, and with several short, simple, or divided
branchlets near the apex, ultimate branchlets spinulose,
septate, slightly constricted at the septa, smoky-brown,
200-300 X 12-16 fj, ; conidia broadly elliptical or subglobose,
apiculate, almost colourless, 10-12 p diam., forming
globose heads.

Sclerotinia bulborum, Rehm, Krypt.-Flora, p. 819.—
Ascophores 1-3 in number, springing from an irregularly
elliptical sclerotium, blackish externally, 8-12 mm. diam.;
at first closed, then expanding, brown, 3-5 mm. • stem
slender, 10-15 mm- l°ng; asci narrowly cylindrical; spores
8, elliptical, 14-16x7-8 /*; paraphyses slender.

Botrytis form. — Compact, brownish-buff tufts, tips of
fertile branchlets spinulose, each spine bearing a smooth,
hyaline, elliptical, apiculate conidium, 9-10x7 /*.

Sclerotinia oxycocci, Wor., Mem. Acad. St. Petersb., 1888,
p. 28, pi. vii. — Ascophore slenderer than in 6". vaccinii^
stem slender, crooked, 5 mm. long, fixed to the ground by
rhizoids, springing from a fruit sclerotium ; asci cylindrical,
spores 8, of two different sizes, 4 measuring 12-14x6/4
and 4 measuring 8x3-4^; paraphyses clavate, tips brown.

Conidia Oidium-lfee, forming a whitish mould on leaves
and slender branchlets ; broadly elliptical, 25-28 X 16-22 /* ;
disjunctors present.

Sclerotinia urnula, Rehm, Krypt.-Flora Disc., p. 804
( = S. vaccinii) Wor.). — Ascophore solitary, rarely two
from a fruit-sclerotium, chestnut-brown, 5-15 mm. broad,
stem usually crooked, slender, 2-10 cm. long, fixed to the
ground by rhizoids near the base ; asci cylindrical, 150-
180X7-8 /x, 8-spored, spores of two sizes, elliptic-oblong,
ends obtuse, the four largest 12-15x5-6 /*, the other four

ASCOMYCETES 381

slightly smaller ; paraphyses slightly clavate, tips brownish.
Conidia Otdium-\\\iQ. Forming a delicate white mould
on leaves and twigs. Conidia in chains, lemon-shaped,
31-32 x 19-25 fj.; disjunctors present.

Sclerotinia baccarum, Rehm, Hedw., 1885, No. i.—
Ascophores usually 2-3, from a sclerotium, brown, 3-10 mm.
broad, narrowed into an often crooked, dark stem 0*5-5 cm-
long; asci cylindrical, 120-150X10-12 /A, 8-spored, four of
which are only perfect as a rule, elliptical, ends obtuse,
18-21X9-11 ft', paraphyses septate, clavulate.

Conidial form OtdiumAike, forming a white mould on
the concave side of curved branches, concatenate, nearly
globose, with disjunctors.

Sclerotinia megalospora, Woronin, Mem. Acad. St.
Petersb., 1888, vol. xxxvi. No, 6, p. 35, pi. 9, 10. — Asco
phore solitary, or sometimes two springing from the fruit-
sclerotium, dark brown, 3-7 mm. broad ; stem very slender,
2-4 cm. long ; asci cylindrical, very large, 8-spored ; spores
elliptical, 19-25x14-16 //,; paraphyses stout, branched
above, septate.

Conidia Oidium~\\\iQt forming a greyish hue on the nerve
of the under side of the leaf, produced in chains, globose,
24-30 p diam. ; disjunctors minute.

** Ascigerous form only known.

Sclerotinia sclerotiorum, Massee, Brit. Fungus-Flora,
iv. p. 280. — Solitary or 2-4 ascophores springing from a
black, usually elongated, often irregular sclerotium 1-2 cm.
long ; at first small and closed, expanding until almost plane,
pale brown, 3-7 mm. broad ; stem slender, 1-3 cm. long ;
asci narrowly cylindrical; spores 8, elliptical, 9-13X4-6 /A;
paraphyses slender.

382 PLANT DISEASES

Sclerotinia tuberosa, Fckl., Symb. Myc.> p. 331. —
Ascophores 2-6, springing from an irregularly elliptical
sclerotium, up to 3Xi'5 cm. buried in the ground, ex-
ternally black, inside white ; ascophore at first pear-shaped
and closed, then funnel-shaped, finally almost plane, bright
brown, 1-3 cm. across; stem slender, 2-7 cm. long; ascus
cylindrical; spores elliptical, 15-18x6-7 /a; paraphyses
septate, slightly thickened upwards.

Sclerotinia trifoliorum, Erik., Kgl Landtbr. Ak. Handl^
1880, No. i. — Apothecia usually solitary, springing from a
small black sclerotium, at first closed, then expanding,
yellowish-brown, i-iomm. across; stem slender, 3-28 mm.
long; asci cylindrical, 160-180 x 12-14 /*; spores elliptical,
ends obtuse, 16-18x8-9 /*; paraphyses slender, septate, up
to 7 /A thick at the enlarged apex.

* * * Conidial form only known.

Sclerotinia galanthi, Ludw., Lehrb. d. nied. Krypt^
p. 355. — Ascigerous condition unknown.

Conidial stage (Botrytis (Polyactis) galanthina, B. and
Br.). Forming a grey mould on dying leaves and flower-
spathes; hyphae shortly branched upwards, coloured,
branchlets thickened at the tips; conidia obovate i5-i8x
lo-n /*, forming heads, springing from slender sterigmata.
Numerous small black sclerotia are formed on the dead
parts of the host, and in the bulb scales.

Sclerotinia douglasii, Massee ; Botrytis douglasti,
Tubeuf, Beitr. z.Baumkr., 4, tab. i ; Sacc., SylL x. 536.—
Conidiophores brownish, passing through the stomata,
solitary or fasciculate, branched towards the summit, almost
continuous, branchlets dilated and denticulate at the

ASCOMYCETES 383

tips; conidia grouped in heads, almost colourless, about
9X6 /*.

On living leaves and youngest internodes of seedling
Abies douglasii and Sequoia gigantea.

Distr. — Germany, Holland, England.

Sclerotinia parasitica, Massee ; Botrytis parasitica,
Cavara, App. Pat. Veg., 10, tab. vi. f. 1-4; Sacc., SylL, x.
536. — Conidiophores grey, scattered, erect, basal joint
inflated ; conidia obovate, large, shortly pedicellate, on
short umbellately arranged branchlets, hyaline or tinged
grey, 16-21 X 10-13 /* j sclerotia formed in the parenchyma
of the host, globoso-depressed, smooth, greyish, then
black, 2-3 mm. diam., sometimes numerous, and forming
black crusts.

Botrytis on leaves, stem, and flowers of cultivated tulips;
sclerotia more especially on the bulbs.

Distr. — Holland, Britain.

Sclerotinia paeoniae, Massee ; Botrytis (Phymatotrichum)
paeoniae, Oud., Comptes Rendus de FAcad. Sci. Pays-Bas,
1897. — Conidiophores pale brown, erect, very numerous,
not caespitose, but equally diffused over the infected part,
•J-i mm. high, branched upwards, branchlets 3-5, spirally
arranged, spreading, simple or variously divided, tips
dilated, muriculate. Conidia forming heads, oblong or
ovate-oblong, colourless or tinged, attached to very slender
sterigmata springing from the inflated tips of the branch-
lets. On the stems of cultivated paeonies.

Distr. — Holland, England.

Sclerotinia douglassii, Massee = Botrytis douglassii,
Tubeuf. — Mycelium endogenous, fuliginous, septate, 14 ft
thick ; fertile hyphae subfasciculate, tinged brown, erect,

384 PLANT DISEASES

dendroidly branched upwards, subcontinuous, branchlets
spreading, tips dilated, toothed ; conidia crowded in heads,
ovoid, subhyaline, 9 X 6 \i. Minute black sclerotia are
formed in the parts attacked. Ascigerous stage un-
known.

Peziza, Dill. — Ascophore sessile, fleshy, brittle, closed
at first, gradually expanding, often until quite flat, or even
recurved, externally warted or scurfy; flesh composed of
large polygonal cells ; asci cylindrical, 8-spored ; spores in
i row in the ascus, hyaline, elliptical, continuous; para-
physes present.

Peziza vesiculosa, Bull. — Clustered, fragile, globose, and
closed at first, gradually expanding, disc pale brown, exter-
nally brownish, granular, whitish downy towards the base,
1-2 in. across ; tissue parenchymatous, cells irregularly
polygonal, large ; asci cylindrical, 8-spored, spores in one
row, smooth, hyaline, bluntly elliptical, 21-24X11-12 /z ;
paraphyses septate, clavate. Conidial stage (=Oedo-
cephalum fimetarium, Reiss) white, with erect fertile hyphae
having the apex globose and studded with very delicate
spicules, from which the conidia spring and form a dense
head. Conidia hyaline, continuous, obovate, 8-ioX
3*4 M-

Bulgaria, Fries. — Ascophore more or less gelatinous,
erumpent, at first closed, the disc gradually expanding and
becoming plane, narrowed into a short, thick, stemlike
base ; asci narrowly clavate, 4-8 spored ; spores in one row
in the ascus, continuous, brown ; paraphyses slender, tips
curved.

Bulgaria polymorpha, Wettst. — Gregarious or clustered,
bursting through the matrix as a rusty-brown, scurfy knob,

ASCOMYCETES 385

the disc gradually expanding until flat, black, shining,
J-iJ in. across ; flesh gelatinous, brown ; asci usually con-
taining only four elliptical, slightly curved, brown spores,
measuring 10-14 X 5-6 /*,; paraphyses brownish, curved at
the tip.

Rhizina, Fries. — Ascophore sessile, expanded from the
first, and forming a crustlike, fleshy structure, furnished
on the under surface with numerous fibrillose, rootlike
strands ; asci cylindrical, 8-spored ; spores continuous,
hyaline, elliptical, or fusiform ; paraphyses present.

Rhizina inflata, Quelet. — Crustlike, wavy, bay-brown, or
umber, margin paler, form variable, often lobed, smooth,
1-3 in. across, rhizoids pale, numerous ; asci cylindrical ;
spores 8, fusiform, tinged brown at maturity, 32-36 x
9-10 //. ; paraphyses septate, clavate, tips brown, mixed
with the paraphyses are stouter, brown, clavate bodies
without septa.

Cyttaria, Berk. — Ascophore obovate or subglobose,
fleshy, stuffed, or hollow, surface furnished with alveolae
lined by the hymenium, and at first covered by a veil ;
asci cylindrical, 8-spored ; spores continuous, hyaline,
elliptical, smooth ; paraphyses numerous.

Cyttaria darwinii, Berk., Linn. Trans., xix. p. 37. —
Whitish, globose, 2-4 cm. diameter, at first even, then
alveolate, always stuffed; asci 150-160X10 /x ; spores 8,
uniseriate, elliptical, ends obtuse, smooth, 14-16x8 p.

Fischer states that spermogonia are immersed in the
lower part of the ascophore, containing elliptical conidia
2X1-5 /^.

Cyttaria hookeri, Berk., Hook., Fl. Antarct., p. 452. —
2 B

386 PLANT DISEASES

Yellowish-cinnamon, obovate, umbonate, 1-2 cm. high,
stuffed, even, glabrous, fertile loculi apical; asci 200-250 x
20 fj.; spores elliptical, ends obtuse, tinged olive, 15 X
10 /A; paraphyses tinged olive at the tip.

Cyttaria gunnii, Berk., Hook., Lond.Journ., 1848, p. 576,
tab. xx., xxi. — Broadly piriform, at length hollow, smooth,
loculi small, dehiscing by an irregular, large opening, densely
gregarious, 1*5-2 '5 cm. broad, whitish ; asci cylindrical ;
spores broadly elliptical, i-seriate, hyaline.

Cyttaria berterii, Berk., Linn. Trans., xix., p. 37.—
Yellow or orange, obovate 1-3 cm. diam., loculi sub-
globose, at first closed; asci cylindric-fusoid, 100X7-8 /*;
spores elliptical, ends obtuse, 15 X 5-6 //- hyaline, 2-guttulate
— possibly becoming i-septate.

BASIDIOMYCETES

Spores produced (usually four in number) at the apex of
continuous (non-septate) basidia. Basidia closely packed
side by side to form the hymenium, which may be exposed
from the first (Hymenomycetes), or enclosed in a peridium
until maturity (Gastromycetes).

Agaricaceae. — Hymenium occupying the entire surface
of radiating gills or lamellae. Sporophore with a central
stem, dimidiate, or rarely resupinate.

Armillaria, Fries. — Pileus symmetrical, more or less
fleshy; gills adnate or slightly decurrent; stem central,
passing continuously into the flesh of the pileus, furnished
with a ring ; spores white, elliptical.

Armillaria mellea, Vahl. — Pileus 2-5 in. across, convex,
then expanded, often dark or covered with olive down

BASIDIOMYCETES 387

when young, then honey-colour, with minute scales ; gills
adnato-decurrent, white, with a pallid tinge; stem 3-5 in.
long, dingy ochraceous, honey-colour below, often more or
less floccose below the ring; spores white, elliptical, QX
5-6 p.

Usually tufted, with blackish, cordlike mycelium per-
meating the bark or soil.

Armillaria mucida, Schrad. — Pileus 1-4 in. across,
hemispherical, then flat, whitish, or grey, very glutinous ;
gills broad, white ; stem 2-5 in. long, thickest at base,
white, often with dark squamules, ring tumid; spores
elliptical, 14-16x8-9 /x.

Often clustered.

Marasmius, Fries. — Tough, thin, dry, reviving their
form when moistened (not putrescent). Veil absent (except
in one sp.) ; stem cartilaginous or horny; gills tough, sub-
distant or distant, often connected by veins, edge acute ;
spores white or pallid.

Marasmius semiustus, Berk, and Curt. — White, becoming
rufous when dry ; pileus excentric, convex, then plane,
rugulosely sulcate, glabrous, J-f in. across ; gills approach-
ing the stem, distant, connected by wrinkles ; stem J in, or
more long, compressed, glabrous, producing a small, whitish
sclerotium in the decaying tissues of the host, 2-3 mm.
diam.

Marasmius sacchari, Wakker, De Ziet. van het Suikerriet
op Java, p. 194, pi. v. (1898). — Gregarious or fasciculate at
the base, variable, flesh membranaceous, persistent ; pileus
white, broadly campanulate, then dingy white and plane or
cup-shaped, 15 mm. diam.; gills white, simple, or bifur-
cate; stem central, white, 15 mm. long, apex tubiform,

388 PLANT DISEASES

base villous, hyphae white ; spores hyaline, continuous,
irregularly oblong, ends attenuated, rounded, i6-2oX
4-5 /*•

Schizophyllum, Fries. — Pileus without flesh, dry ; gills
coriaceous, flabelliformly branched, edge split open longi-
tudinally.

Schizophyllum commune, Fries. — Pileus very thin, fan-
shaped, white or grey, downy, often lobed, 1-2 in. broad;
gills pale brown with a purple tinge, split portions of
edge of gills revolute ; spores dingy, 4-6 x 2-3 p.

Pholiota, Fries. — Pileus more or less fleshy ; gills adnate,
with or without a decurrent tooth, or rounded behind and
adnexed, tawny or ferruginous at maturity, as are also the
spores ; stem central, furnished with a distinct interwoven
ring.

Pholiota aurivella, Batsch, Consp.^ f. 115. — Pileus 3-6 in.
across, fleshy, campanulate, then convex, gibbous, slightly
viscid, tawny yellow, variegated, with adpressed, darker
scales; gills sinuate, ad fixed, 2-3 lines broad, white, then
straw-colour, finally rusty umber ; stem 4-6 in. long, almost
equal, curved, yellowish, with scattered, adpressed, rusty-
brown, floccose squamules, stuffed, often hollow with age;
ring rather distant, imperfect; spores elliptical, 5X2*5 /*.

Pholiota squarrosa, Mull, Fries, Syst. Myc. i. p. 143.—
Pileus 2-4 in. across, fleshy, campanulate, then expanded,
often gibbous, dry, yellowish-brown, covered with darker,
innate, squarrose scales; gills slightly decurrent, crowded,
about 2 lines broad, pallid olive, then ferruginous ; stem
3-5 in. long, 3-5 lines thick, slightly narrowed towards the
base, flexuous or ascending, pale tawny-brown and covered

BASIDIOMYCETES 389

with darker, recurved scales as far up as the superior spread-
ing, floccose ring, smooth and pale above the ring, stuffed ;
spores ferruginous, 8X47*.

Pholiota adiposa, Fries, Syst. Myc., i. p. 242. — Pileus 2-4
in. across, fleshy, compact, convex, obtuse, glutinous,
yellow, with concentrically arranged, superficial, seceding,
darker squarrose scales; flesh whitish; gills adnate, 3-4
lines broad, yellow, then ferruginous ; stem glutinous, 3-6
in. long, up to f in. thick, subequal, base somewhat
bulbous, yellow, with concentrically arranged, ferruginous,
evanescent squamules up to the superior, floccose, radi-
ating ring, stuffed ; spores elliptical, ferruginous, 7X3^.

Pholiota destruens, Brond, Crypt. A gen., tab. 6.— Pileus
fleshy, irregular, floccose with paler lanose squamules when
dry, yellowish white, margin involute, fibrillose, 3-4 in.
across ; stem solid, 4-7 in. long, up to i in. thick at
the base, narrowed upwards, albo-squamulose up to the
fugacious ring ; gills adnexed, striato-decurrent, crenu-
late, pallid, then umber- brown ; spores elliptical, 8-9 X
5-6 fi.

Hypholoma, Fries. — Pileus fleshy, margin incurved when
young ; stem central ; veil interwoven, adhering in frag-
ments to the margin of the pileus (appendiculate), not
forming a distinct ring on the stem ; gills adnate or sinuate ;
spores purple-brown or deep purple.

Hypholoma fasciculare, Huds. — Fasciculate ; taste in-
tensely bitter; pileus '1-3 in. across, convex, then expanded,
subumbonate, thin, glabrous, tawny, margin yellow; gills
adnate, closely crowded, narrow, yellow, then greenish, sub-
deliquescent ; spores elliptical, 7 x 4 /*. Stem 3-4 in. long,

390 PLANT DISEASES

fibrillose, hollow, yellow as is also its flesh; veil sometimes
appendiculate.

Polyporaceae. — Sporophore with a central stem, dimi-
diate, or resupinate ; hymenium lining the cavities of long
or short, densely packed tubes, or shallow depressions;
basidia tetrasporous.

Polyporus, Mich. — Stem central or lateral, or sessile and
dimidiate, etc. ; pileus fleshy, tough, rather soft and moist,
at length becoming harder (rarely of a cheesy texture and
fragile), externally neither sulcate nor zoned, but the
internal texture consisting of radiating fibres often more
or less zoned ; pores never stratose ; tubes not separable
from the sporophore, pores at first obsolete, then rounded,
angular, or torn.

Polyporus schweinitzii, Fries, Syst. Myc., i. p. 351. —
Pileus 12-20 cm. across, tomentose, tomentum matted into
little rugged tufts, dark brown with a rusty tinge ; flesh
thick, spongy, fibrous, brown ; stem thick, very short,
brown, sometimes obsolete, more or less central when
present ; tubes about i cm. long, pores large, irregular,
and variable in form, yellow, with a tinge of green ; spores
elliptical, obliquely apiculate, pale yellow, 7-8X4 /*.

Polyporus squamosus, Fries, Syst. Myc., i. p. 343.—
Broadly flabelliform, fleshy but thin, pliant, pale yellow
or whitish, with large adpressed, centrifugally arranged
brown scales, 12-25 cm- across, single or usually several
pilei springing from the same knob ; stem excentric or
lateral, short, base black ; tubes very short, becoming
large, angular, running down the under side of the stem,
whitish ; spores elliptical, colourless, 12X5 p.

Polyporus giganteus, Fries, Syst Myc., i. p. 356.—

BASIDIOMYCETES 391

Formed of numerous imbricated pilei forming clusters
several feet across ; stem short, much branched, springing
from a tuberous base ; pilei thin, fleshy, tough, then
coriaceous, dimidiate, flaccid, slightly zoned, rivulose,
depressed behind, bay-brown ; tubes very short, pores
minute, roundish, at length torn, pallid, becoming dark-
coloured when bruised.

Polyporus sulphureus, Fries, Syst. Myc., i. p. 357.—
Horizontal, attached by a broad base, usually imbricated,
undulate, almost glabrous, yellow, pale flesh-colour, or
tinged red, 10-20 cm. across ; flesh thick, yellow, then
whitish, cheesy; pores up to 1-5 cm. long, pores minute,
plane, sulphur-colour ; spores elliptical, hyaline, slightly
papillose, 7-8 X 4-5 p ; smell unpleasant.

Polyporus dryadeus, Fries, Syst. Myc.^ i. p. 374 (in part).
— Pileus 10-25 cm. across, 6-10 cm. thick, semicircular,
sessile, horizontal, attached by a broad base, pulvinate,
fleshy, then corky, cuticle thin, soft, smooth, rugged,
becoming even, ferruginous, then brown, margin often
exuding drops of water ; flesh ferruginous, somewhat
zoned, rather velvety, fibrous when cut ; tubes 2-5 cm.
long, thin, soft, ferruginous, pores round, paler, about
J mm. across ; spores colourless, elliptical, 5 X 3 /*.

Polyporus hispidus, Fries, Syst. Myc., i. p. 362. — Pileus
sessile, attached laterally, horizontal, more or less convex,
compact, fleshy, rusty-brown, hispid, 10-18 cm. broad;
flesh spongy, ferruginous, formed of diverging fibres, 2-5
cm. thick ; tubes 2-3 cm. long, yellowish, then brown, but
paler than the pileus, pores minute, margin fimbriate,
inclined to separate, often exuding water in drops ; spores
elliptic, oblong, orange-brown. 10x7 /*•

392 PLANT DISEASES

Alcohol dissolves out of any part of the fungus a yellow-
brown colouring matter.

Polyporus betulinus, Fries, Syst. Myc., i. p. 358. — Pileus
8-15 cm. across, thick, corky, elastic, hoof-shaped, sessile,
obliquely umbonate behind at the point of attachment,
margin obtuse, incurved, sterile, pileus covered with a
thin, greyish, brownish, or whitish crust which peels off,
exposing the white flesh, zoneless, glabrous ; pores up to
f cm. long, pores minute, unequal, whitish ; spores white.

Polyporus borealis, Fries, Syst. Myc., i. p. 366. — Hori-
zontal, subspathulate, or reniform, either narrowed behind
into a short, more or less distinct stem, or thick and sessile,
4-8 cm. broad, whitish, then dingy yellow, spongy, then
corky, compact, hairy, often radiately rugose, rigid and
incurved when dry ; flesh thick, whitish, formed of parallel
fibres; tubes 4-8 mm. long, pores unequal, white, dis-
sepiments thin, torn ; spores colourless, subglobose, 4 /*
diam. ; inodorous when fresh, but with a slight spicy smell
when dry.

Femes, Fries. — Pileus hard and woody from the first,
flesh composed of interwoven hyphae, covered with a hard,
crustaceous cuticle, not zoned but often concentrically
grooved; perennial, forming successive strata of tubes,
the last formed and external layer of pores only living.

Fomes fomentarius, Fries, Syst. Myc., i. p. 374. — Hoof-
shaped, 10-20 cm. across, 8-15 cm. thick at the base,
distantly concentrically sulcate, glabrous, opaque, fuliginous
or dingy brown, cuticle thick, hard, persistent, margin at
first with a white bloom, then ferruginous ; flesh rather
soft, compactly floccose, foxy rust-colour ; tubes very long,
2-6 cm. long, distinctly stratose, ferruginous, pores sub-

BASIDIOMYCETES 393

angular, about J mm. across, powdered with white at first,
then ferruginous; spores brown, elliptical, base abruptly
truncate, 6x3-5-4 /*.

Fomes igniarius, Fries, Syst. Myc., i. p. 375.— At first
tubercular, immarginate, even, with a thin, flocculose,
adpressed hoary covering, then thinly hoof-shaped, fer-
ruginous, at length blackish-brown, opaque, cuticle very
hard, margin rounded ; 10-15 cm- across, sometimes larger;
flesh zoned, ferruginous, very hard ; tubes 2-6 cm. long,
stratose, very small, when old, filled with white mycelium,
general surface of hymenium convex, pores \-\ mm. across,
rounded, at first hoary; spores subglobose, hyaline, 6-7 /*,
cystidia few, 10-25x5-6 p.

Fomes pinicola, Fries, Elench., p. 105.— Pileus woody,
pulvinate, then hoof-shaped, glabrous, unequal, tawny, then
becoming blackish, margin cinnabar when mature; flesh
hard, pallid ; pores minute, pallid, then yellowish-white.

Large, truly perennial and reviving, growing by additions
to the margin, pores not distinctly stratose ; odour acid.

Fomes fulvtis, Fries, Epicr., p. 465.— Pileus woody, very
hard, triangular in section, sessile, attached by a broad
base, even (not concentrically sulcate), at first villose,
tawny inside and out, then hoary ; pores short, rounded,
minute, cinnamon, at first covered with a greyish-yellow
bloom ; three to four in. across, sometimes imbricated.

Fomes annosus, Fries, Syst. Myc., i. p. 375. — Very
irregular in form, often horizontal and imbricated ; pileus
convex, becoming plane, tuberculoso-zoned, radiately
rugulose, during the first year brown, silky, margin
whitish, second season covered with a glabrous, blackish-
brown rigid cuticle, 10-16 cm. across; flesh rather thick,

394 PLANT DISEASES

whitish ; pores at first pure white, about J cm. long,
medium size; spores colourless, elliptic-oblong, 6x4 /*.

Biscuit-like sporophores, entirely white, are often formed
on subterranean roots.

Fomes ribis, Fries, Syst. Myc.^ i. p. 375. — Imbricated,
horizontal, coriaceous, rigid, flattened, almost even, fer-
ruginous, velvety, margin acute, base often thinner than
the margin, 6-10 cm. across ; flesh thin ; tubes about 2 mm.
long, pores minute, tawny.

Poria, Pers. — Entirely resupinate, forming more or less
extended patches or thin membranaceous expansions, often
inseparable from the matrix ; pores covering the entire
surface except the extending margin.

Poria vaporaria, Fries, Syst. Myc., i. p. 382. — Broadly
effused, thin, inseparable, the white mycelium penetrating
the matrix ; pores large, angular, or inclined to be sinuous,
often oblique, dissepiments often eroded ; entire fungus
white, then straw-colour or ochraceous.

Trametes, Fries.— Sporophore corky or woody, dimidiate
or resupinate; pores roundish, often elongated radially;
dissepiments rather thick, unequal in depth, and not
forming a heterogeneous stratum, hence the trama is
continuous with the flesh of the sporophore.

Trametes pini, Fries, Syst. Myc., i. p. 336. — More or
less semicircular in outline, horizontal, attached by a broad,
thick base ; pileus rusty-brown, then blackish, concentric-
ally sulcate, rough, margin strigose ; flesh rusty, hard ;
pores irregular in form, deep and indistinctly stratified in
old specimens, bright ferruginous with a yellow tinge,
becoming dusky.

BASIDIOMYCETES 395

More or less triangular in section, 2-5 in. across ; smell
slight, pleasant.

Trametes suaveoleus, Fries, Epicr., p. 491. — Horizontal,
3-6 in. across, often i in. or more thick at the point of
attachment, becoming thinner towards the margin; pileus
villose, whitish, zoneless ; flesh thick, white, corky ; pores
J in. or more in length, irregularly rounded, rather large,
white, becoming fuscous ; spores cylindric-oblong, 6 X 2*5 //, ;
odour distinctly spicy.

Daedalea, Pers. — Dimidiate or resupinate; firm, corky,
or woody ; pores becoming elongated and irregularly
sinuous, dissepiments corky and often flexible ; basidia
tetrasporous ; spores hyaline.

Daedalea QLuercina, Pers., Syn. Fung.) p. 500. — Pileus
dimidiate, sessile, 4-10 in. across; every part pale wood-
colour, upper surface rugulose, uneven ; fleshy, corky,
elastic; pores at first rounded, becoming very much
elongated and contorted, broad ; dissepiments very thick,
flexible.

FistUlina, Bull.— Hymenium formed on the under surface
of a fleshy hymenophore, at first warted, the warts develop-
ing into cylindrical tubes which remain distinct and free
from each other, and bearing the tetrasporous basidia
in their interior; conidia produced in cavities of the
hymenophore.

Fistulina hepatica, Fries, Syst. Myc., i. p. 396. — Pileus
roundish in outline, or subspathulate, dimidiate, attached
by a broad base, or substipitate, blood-red, fleshy, and soft,
streaked internally ; tubes at first pallid, then red ; spores
broadly elliptical, salmon-colour, 5-6X3-4 /*; conidia
6-10X5 /Jt, salmon-colour.

396 PLANT DISEASES

Merulius, Hall. — Hymenium developing on a loose weft
of mycelium, surface variously plicate or wrinkled, the folds
forming irregular pores, and sometimes obsoletely toothed ;
spores colourless or coloured; substance often sub-
gelatinous.

Merulius lacrymans, Fries, Syst. Myc., i. p. 328 (1821).
— Broadly effused, usually entirely resupinate, but some-
times effuso-reflexed, thick, soft, and rather moist, silky or
velvety below, yellowish-brown in the centre, shading off
to the tumid, silky, white, or yellow margin; folds of
hymenium wavy, forming irregular pits ; spores rusty-
yellow, obliquely elliptical, 10-12 x 5-6 /x.

Hydnaceae. — Hymenium borne on acute spines, teeth,
warts, or irregular folds; basidia tetrasporous except in
Knieffia and Mucronella, where they are said to be mono-
sporous.

Hydnum, Linn. — Hymenium inferior or superior, borne
on pointed spines that remain perfectly free and distinct
from each other at the base.

Hydnum schiedermayeri, HeufL, Oest. Zool. Bot. Zeitschr.,
1870, p. 33. — Fleshy, broadly effused, immarginate, 4-10
in. across, irregularly tuberculose, with tufts of pendulous,
subulate spines up to i in. long, often compressed, and
the tip more or less fimbriate ; flesh yellow, becoming
rufescent.

Hydnum diversidens, Fries, Syst. Afyc., i. p. 411. —
Pileus 2-3 in. across, fleshy and irregularly tuberculose or
lobed, sometimes substipitate, whitish or yellowish, upper
surface with erect, irregularly notched teeth ; the margin
clothed with club-shaped, sterile teeth ; under surface with
simple, awl-shaped, regular spines 3-6 lines long.

BASIDIOMYCETES 397

Thelephoraceae. — Sporophore with a central stem, dimi-
diate, or resupinate ; hymenium smooth or with only very
slight traces of inequality of surface ; basidia tetra-
sporous.

Stereum, Pers. — Furnished with a central stem, sessile
and dimidiate, or entirely resupinate ; hymenium smooth,
even, originating from a compact, intermediate layer ;
basidia tetrasporous, hyaline, or tinted.

Stereum hirsutum, Fries, Epicr., p. 549. — Wholly
resupinate, or most frequently effuso-reflexed, the upper
portion projecting at right-angles from the matrix, and
often crisped or lobed ; pileus coarsely strigose, dingy
ochraceous, becoming pale and greyish, indistinctly zoned,
flesh thin, tough, and pliant ; hymenium even, glabrous,
naked, bright ochraceous, or pale tan colour j spores
elliptical, hyaline.

Stereum frustulosum, Fries, Epicr., p. 552. — Tuber-
culose, woody, crowded, and almost confluent, looking like
one much-cracked specimen, under surface and glabrous
margin brownish-black ; flesh distinctly stratose ; hymenium
convex, cinnamon, becoming pale, pruinose; spores ellip-
tical, ends subacute, 4-5X3-3*5 /*.

Corticium, Fries. — Hymenophore broadly effused, en-
tirely adnate to the substratum ; hymenium smooth, waxy,
consisting of basidia and paraphyses only which spring
directly from the mycelium without an intermediate com-
pact stratum ; spores continuous, hyaline.

Corticium comedens, Fries, Epicr., p. 565 (1836-38). —
Effused, inseparable, formed below the cortex and exposed
by the rupturing and recurving of the bark, dingy lilac.

39§ PLANT DISEASES

becoming pale, spores cylindric-ellipsoid (sausage-shaped),
slightly curved, 14-16x6-7 /A.

Hypochnus, Fries. — Resupinate, membranaceous, texture
loose, homogeneous, floccose, collapsing; hyphae filiform,
branched and anastomosing, the tips of the uppermost
branches becoming changed into basidia bearing 2-4-6
sterigmata ; spores elliptical or globose, hyaline, or coloured ;
epispore smooth or rough.

Hypochnus cucumeris, Frank, Hedw., 1883, p. 127.—
Forming grey or greyish-brown membranaceo-fibrillose
patches on the lower part of the stem of the host, up to
i mm. across ; basidia elongated, bearing four sterigmata
at the apex ; spores ovoid, hyaline.

Hypochnus solani, Prill, and Del., Bull. Soc. Myc., 1891,
p. 220, fig. — Membrane effused, thin, slightly granular,
cracked when dry, scarcely adhering to the cuticle, greyish
white, internally brownish ; basidia globoso-ovate, apex
rounded ; spores hyaline, ovate, base apiculate, 10x6 /*.

Exobasidium, Woronin. — Effused, incrusting, waxy ;
basidia crowded, cylindric-clavate, bearing a variable
number of spores at the apex.

Typically parasitic on living plants, which are deformed
by the fungus.

Exobasidium rhododendri, Cramer, in Rabenh. Fung.
Eur., No. 1910. — Forming gall-like swellings on the leaves,
at first pale-green, becoming more or less tinged red;
basidia stout, number of sterigmata variable, often four;
spores hyaline, smooth, broadly elliptical, 8-10x6-7 /u.

Exobasidium vexans, Massee, Kew Bulletin, 1898, p.
in, figs. 6-10. — Forming large blisters on the leaves,

BASIDIOMYCETES 399

convex on the upper surface, remaining green (so far as
observed), 4-12 mm. diam., the convex surface becoming
minutely velvety from the hymenium ; basidia cylindrical,
30-35 X 5-6 //., bearing 2 sterigmata ; spores ovate-oblong,
continuous, hyaline, glabrous, 5X3^; conidia developed
before or along with the basidia, fusiform, hyaline, i-septate,
slightly constricted, 14-16x5-6 /x.

Exobasidium lauri, Geyl., Bot. Ztg., 1874, p. 322, tab.
vii. — Effused, yellowish, then brownish, smooth, forming
woody club- or horn-shaped excrescences 5-10 cm. long;
basidia cylindric-clavate, apex rounded and bearing four
sterigmata, mixed with filiform paraphyses ; spores oblong,
curved, base somewhat acute, hyaline, 15-16 //, long.

Exobasidium vitis, Prillieux, Malad. des PI. Agric.y i. p.
298 — Pustules numerous, distinct from each other, small,
somewhat golden in colour; fertile branches forming the
basidia ; number of spores borne by the basidia variable,
often six, cylindrical, slightly curved, 6-25 x 1-5 /x.

HEMIBASIDIOMYCETES

Basidia elongated, transversely septate, each cell pro-
ducing a spore; basidia densely packed side by side to
form the hymenium.

Hirneola, Fries. — Cartilagineo-gelatinous, soft and tre-
melloid when moist, rigid when dry ; sporophore cup-
shaped or saucer-shaped, thin ; basidia rod-shaped or
fusoid, transversely septate, each cell producing a single
monosporous sterigma ; spores hyaline, oblong, curved.

Hirneola auricula-judae, Berk., OutL, p. 289, pi. 18, f. 7.
— Thin and elastic when moist, becoming dark brown or

400 PLANT DISEASES

blackish, hymenium venoso-plicate, 1-3 in. across; spores
reniform, 20-25 X 7~9 f > pileus greyish-olive, minutely
tomentose.

Helicobasidium, Pat. — Resupinate, incrusting, soft ;
basidia straight at first, then distinctly curved at the apex,
with a variable number of transverse septa, bearing 2-4
sterigmata from the convex surface of the curved portion ;
spores hyaline, continuous, ovoid, often slightly curved.

Helicobasidium mompa, Tanaka, Journ. Coll. Sci. Imp.
Univ. Japan, vol. iv. pt. i. pi. xxiv.-xxvii. (1891). — Pileus
sessile, resupinate, somewhat orbicular or oblong, often
irregularly lobed, 5-10 cm. across, 2-4 mm. thick, at first
velvety and membranaceous, then subcoriaceous, some-
what convex, incrustate, purplish-brown, at length albo-
pruinose ; hymenium white ; basidia curved, i-3-septate,
tetrasporous ; sterigmata elongated ; spores ovoid, curved,
hyaline, 10-12X5-7 /*.

USTILAGINACEAE

Mycelium parasitic in the tissues of living plants, abun-
dant, but soon disappearing; teleutospores formed in the
interior of hyphal branches, which often become gelati-
nous ; spores on germination producing a continuous or
sparingly septate promycelium, which bears secondary
spores. Secondary spores either producing a delicate
germ-tube, or bearing conidia, which often reproduce
themselves by gemmation.

Ustilago, Pers. — Vegetative mycelium spreading in the
tissues of the host, soon disappearing ; spore producing
hyphae branched, the spores formed in the interior of
gelatinised, clustered terminal branches; spores i-celled,

USTILAGINACEAE 401

on germination producing a short, septate promycelium,
which bears minute, lateral, and terminal secondary
spores.

Ustilago avenae, Jensen. — Spore-mass blackish-brown,
soon pulverulent, formed in the ovary ; spores globose or
broadly elliptical, 6-8 ft diam., or 7-9x6-7 //, delicately
verruculose ; promycelium septate, sporidiola oblong,
produced at the septa.

Var. levis, Kell. and Swing., 11. Rep. Agr. Kansas, p. 25,
tab. 5, f. 56-60. — Spores smooth and slightly darker in
colour than in the type form.

Ustilago tritici, Jensen, in Kell. and Swing., 11. Rep.
Agr. Kansas, p. 214 and 262, tab. 2 and 6. — Spore mass
dark olive-brown, loose, formed in the ovary ; spores
ovoid, elliptic, or subglobose, 5 '5-7*5x5 -6 /x, dilute olive,
minutely verruculose ; promycelium branched, septate ;
secondary spores.

Forma folicola, P. Henn., Zeitschr. fiir Pflanzenkr.^ 1894,
p. 139. — Developed on leaves and leaf-sheaths of Triticum
vulgare\ spores either quite smooth, or delicately punc-
tulate, yellowish olive-brown, 4-5-7 X 4*5-6 /x.

Ustilago nuda, Kell. and Swing., u. Rep. Agr. Kansas, pp.
215 and 277, pi. 2, f. 7-17. — Spore-mass olive-brown, pro-
duced in the ovary, soon free and powdery ; spores ellip-
tical to globose 5-7 X 5-6 ft, olive-brown. The promycelium
does not produce secondary spores, but forms a sparingly
branched, septate mycelium.

Ustilago hordei, Kell. and Swing., n. Rep. Agr.
Kansas, pp. 215 and 268, pi. 2, f. 2-6. — Spore-mass black,
compact, not becoming pulverulent, and enclosed in the

2 C

402 PLANT DISEASES

ovary ; spores globose or subangular from mutual pressure,
blackish-brown, 6-7-5 /* j promycelium 3-4-septate, pro-
ducing secondary spores.

Ustilago maydis, Corda. — Forming large tubercular
masses on the inflorescence, often many centimetres in
diameter, also corrugated pustules on the leaves ; pustules
at first covered by the silvery epidermis, then olive-brown
and pulverulent ; spores globose or broadly elliptical,
8-13X8-11 ju, pale brown, pellucid, minutely aculeate;
promycelium 3-4-septate, bearing fusoid secondary spores
at the septa and apex.

Ustilago sorghi, Passer. — Spore-mass blackish-brown,
formed in the ovary or in the anthers, soon pulverulent ;
spores globose, oblong, or angular, 5-9-5 X4~5'5 /*> epispore
smooth, pale olive ; promycelium cylindrical, constricted
near the spore ; secondary spores oblong, numerous.

Ustilago cruenta, Kiihn. — Spore-mass olive-brown,
formed at the apex of the culm and in the branches of
the inflorescence, forming large reddish-brown patches,
rarely in the ovary, the attacked branches are usually much
bent and distorted ; spores globose or broadly elliptical,
5-12X5-9 p', epispore olive-brown, smooth; promycelium
cylindrical, generally 3-septate ; secondary spores elliptic-
fusoid, produced laterally and at the apex.

Ustilago reiliana, Kiihn. — Pustules formed in the
inflorescence, often finger-shaped, at first enclosed in a
silvery membrane, then becoming pulverulent, blackish-
brown ; spores subglobose, pellucid brown, delicately
echinulate, 9-12 /* diam. ; promycelium septate, producing
elliptical secondary spores.

Ustilago emodensis, Berk., Hook, Journ. Bot.^ vol. iii.

USTILAGINACEAE 403

p. 202 (1851).= Ustilago treubii, Solms, Ann. Gard. Bot.
Buitenzorg, vol. vi., 1887, p. 79, pi. ix. — Spore-mass violet,
forming tubercles in the inflorescence, or causing the
formation of clustered, elongated, furrowed outgrowths
up to i in. long, and terminating in a capitate head con-
taining the spore-mass. Spores violet or lilac, smooth,
globose, or broadly elliptical, 5-6 //. diam. ; promycelium
short, continuous ; secondary spores coalescing in pairs
before germination.

Ustilago esculenta, P. Henn., Hedwigia, 1895, P- I0-—
Spore-mass olive-brown, forming spherical or elongated
tubercles in the unexpanded inflorescence, which is de-
stroyed : at first covered by the whitish cuticle ; spores
subglobose, 7-9 X 6-8 /*, brown, smooth.

Ustilago sacchari, Rab., his, 1870. — Spore mass black ;
spores globose or angularly globose, 8-18 /* diam., olive-
brown or rufous ; epispore thick, smooth.

Tilletia, Tul.— Spores isolated, formed by a swelling of
the tips of fertile hyphae, forming a powdery mass at
maturity ; promycelium bearing a terminal cluster of
elongated, cylindric-fusiform secondary spores, which after
conjugating in pairs either give origin to a curved spori-
dium, or protrude a delicate germ-tube.

Tilletia tritici, Winter, Krypt.-Flora, i. p. no (1884).—
Spore-mass produced in the ovary, blackish, with an olive
sheen, foetid; spores globose, brown, 17-22 /x diam.,
border i-i'5 p, not paler; epispore furnished with ridges
anastomosing to form a rather large-meshed network,
meshes often variable in size and form.

Tilletia levis, Kiihn, Rab., Fung. £ur., No. 1697 (1873).

404 PLANT DISEASES

— Spore-mass produced in the ovary, deep brown, with an
olive tinge, foetid ; spores globose, elliptical, etc., variable
in form and size, averaging 17-21 /x, or 15-26 X 10-15 ft ; wa^
about 2 fj, thick, pale olive-brown, or sometimes almost
cream-colour ; epispore perfectly smooth,

Tilletia decipiens, Winter, Krypl.-Flora., i. p. in (1884).
— Spore-mass formed in the ovary, blackish-brown, foetid ;
spores globose, irregularly or angularly globose, or broadly
elliptical, clear brown, 20-27 /A diam. ; border about 3 /*
wide, not appreciably paler ; epispore with raised ridges
anastomosing to form an irregular, small-meshed network.

Urocystis, Rabenh. — Sori erumpent, large, black, pulveru-
lent; glomerules of one or more large, central, dark-coloured,
fertile spores, surrounded by smaller, pale-coloured, sterile
spores ; germination as in Tilletia.

Urocystis colchici, Rab., Fung. Eur., No. 396. — Sori
black, usually large, elongated ; spore-clusters globose or
oblong, 20-33 X 16-20 /*, central spores 2-4, smooth, chest-
nut-brown, 10-15 /* diam.; sterile peripheral spores with
thickish walls, sometimes arranged in two strata, pale
yellowish-brown, 7-11 /x.

Urocystis cepulae, Frost, Ann. Rep. Mass. Board of
Agric., p. 164 (1876-77). — Sori forming large black, pul-
verulent streaks on the leaves and bulb ; spore-clusters
18-25 ju, diam., usually only one dark brown, central, fertile
cell, surrounded by numerous small, pale, sterile cells.

Urocystis occulta, Rab., in Klotzsch Herb. Myc.^ ii.
No. 393; Sacc., Syll., vii. p. 515. — Forming long streaks
on leaf-sheath, leaves, culm, and also in the inflorescence,
at first covered by the epidermis, then black and powdery ;

USTILAGINACEAE 405

glomerules of spores globose or elliptical, iy-24X 15-20 /A,
fertile central spores 18-20 /z diam., dark brown ; peripheral,
pale, sterile spores forming an interrupted zone; spores
soon germinating ; sporidiola rarely conjugating, producing
a germ-tube from the base.

Sorosporium, Rudolphi. — Resting-spores of uniform size,
small, all fertile, at first in dense clusters, soon breaking
up, produced by tufts of intertwined hyphae which become
gelatinised, the entire spore-mass at first involved in
a gelatinous integument ; promycelium filiform ; sporidia
unknown.

Sorosporium scabies, Fischer de Waldh., Aper$u, p. 33.
= Tuberdnia scabies, Berk. — Sori forming large, olive, scab-
like expansions ; spore-clusters globose or elliptic-oblong,
forming a hollow sphere, perforated, here and there, 20-50 p.
diam. ; resting-spores subangular from mutual pressure,
smooth, pale olive-brown, about 5 /* diam.

Described from Berkeley's specimens in Herb. Kew.

Oedomyces, Sacc. — Mycelium very delicate, intercellular,
sporiferous branches bearing a terminal spore, immediately
below which is a large vesicular swelling ; spores rarely
solitary, most frequently occurring in great numbers;
epispore thin, brown, smooth.

Oedomyces leproides, Trabut, Rev. generate Bot., 1894,
No. 70, i pi. ; Sacc., *$>•//., xi. p. 234. — Forming large,
nodulose, fleshy tumours on the upper part of the root of
Beta vulgaris, var. rapacea \ spores globoso-depressed,
umber, 40-50 X 30 ft, acrogenous ; mycelium inflated into
a vesicle below the spore \ spores produced in masses
within spherical cysts in the substance of the tumours.

406 PLANT DISEASES

UREDINACEAE

Mycelium developed in the tissues of living plants.
Spores produced at the tips of hyphae, usually of more
than one kind, as spermogonia, aecidia, uredospores,
teleutospores; the latter on germination form a pro-
mycelium, which is typically 4-septate, each cell producing
a conidium borne on a slender sterigma.

Uromyces, Link. — Spermogonia present in many species;
aecidia having the pseudoperidia usually well developed ;
sori of uredospores flat, small ; son of teleutospores more
or less pulverulent, flattened or pulvinate, teleutospores
i-celled, with a single apical germ-pore, stipitate ; second-
ary spores subhyaline, ovoid or elliptical.

Uromyces appendiculatus, Link., Obs., ii. p. 28.— Sper-
mogonia on white spots; aecidia on spots 1-2 mm. broad,
shortly cylindrical, margin deeply cur, whitish, aecidio-
spores angularly globose, 17-32X14-20, hyaline, slightly
punctulate; uredospores in small pale brown sori, 24-33 X
16-20, pale brown, aculeolate; teleutospores forming small
blackish sori, elliptical or subglobose, smooth, dark brown,
apex much thickened, and with a small, hyaline, wartlike
papilla, 26-35 * 20-26 IJL.

All forms produced on same leaf.

Uromyces colchici, Massee, Grev.t xxi. p. 6. — Sori
numerous, large, elliptical, sometimes circinating, blackish-
brown, on both surfaces of leaf and on leaf-sheath;
teleutospores broadly elliptical or subglobose apex, slightly
prominent, germinating pore i ; epispore dark brown,
smooth, up to 2 fJL thick, 28-38x21-28 p, pedicel hyaline,
persistent, base attenuated, 70-80 x 5-6 /*.

UREDINACEAE 407

Uromyces fabae, De Bary, Ann. Sci. Nat., ser. iv. vol. xx.
1863. — Spermogonia yellowish, in little groups on leaves
and stem ; aecidia scattered in rings or orbicular patches,
margin white, torn ; aecidiospores orange, verruculose,
16-26 p diam. ; uredospores forming powdery, pale brown
sori, globose or irregularly elliptical, etc., ochraceous,
aculeate, 17-35 X 17-25 /x; teleutospores forming blackish-
brown sori, often numerous and confluent, ovoid or clavate-
ellipsoid, smooth, brown, apex darker and thickened,
apiculate, 24-47 x I7~3°/z^ pedicel hyaline, long.

Uromyces betae, Kiihn, Bot. Ztg., 1869, p. 540. —
Spermogonia yellowish, in small groups ; aecidia crowded
on yellowish, often large patches, white, margin torn ;
aecidiospores angularly globose or elliptical, orange, smooth,
22-26x16-22 /*; uredospores forming small sori, often
orbicularly arranged, yellowish-brown aculeolate, or almost
smooth, 23-32X17-24 /A; sori of teleutospores blackish-
brown, scattered, or in groups ; ovate or ellipsoid, smooth,
brown, with an apical hyaline wart, 26-35 X 19-25 /* ; pedicel
slender.

Hemileia, Berk, and Broome. — Sori pustular, orange-
brown, hypophyllous ; spores ovate or piriform, oblique,
i-celled, one portion of the epispore smooth, the remainder
warted ; promycelium one or several ; secondary spores
spherical.

Hemileia vastatrix, Berk, and Broome, Gard. Chron.,
Nov. 6, 1869, figs. — Pustules orange, then rufous: spores
subreniform, attached obliquely at the base, convex free
surface coarsely warted, the two lateral faces that are in
contact with others during growth, smooth, 35-39 X 10-14 /*•

Hemileia woodii, Kalchbr. and Cooke, Grev.t ix. p. 22

408 PLANT DISEASES

(1880). — Sori pulvinate, minute, often densely gregarious,
orange ; spores subreniform, convex, free portion warted,
remainder smooth, 30-35 x 10-12 /*.

The sterile cysts mentioned by the authors are only
young, still smooth spores; the same occurs in H.
vastatrix, when the pustules are examined while young.

Hemileia canthii, Berk, and Broome, Journ. Linn. Soc.
(Bot.} xiv. p. 93 (1875). — Sori scattered on pale spots,
hypophyllous; spores subreniform, free convex surface
warted, remainder smooth, 25-30 X 10-12 p.

Cronartium, Fries. — Aecidia produced on conifer leaves,
pseudosporidia elongated, aecidiospores concatenate ;
uredospores included in a pseudoperidium, brown; teleuto-
spores i-celled, aggregated into a column which springs
from the sorus of uredospores.

Cronartium ribicolum, Deitr., Arch. Naturk. Liv. Esth.
und Kur lands, ii. p. 287. — Aecidiospores large, epispore
warted, one part smooth ; sori of uredospores forming
pustules, orange-rufous, minute, rounded, pseudopericlia
hemispherical, perforated at the apex, uredospores ellipti-
cal or ovoid, 19-35X14-22 //., epispore hyaline, aculeate,
contents orange ; teleutospores forming a columella up to
2 mm. high, curved, yellowish-rufous.

Cronartium asclepiadeum, Fries, Obs. Myc., \. p. 220.—
Aecidiospores 22-26, rarely 30X16-20 /x, epispore partly
reticulated, partly warted; uredospore sori hypophyllous,
scattered, brown ; uredospores variable in form, echinate,
16-32x12-18 fjij pale orange; columella of teleutospores
terete up to 2 mm. long ; teleutospores oblong, truncato-
obtuse, 12 /A broad ; sporidiola globose, smooth, pale
yellow,

UREDINACEAE 409

Cronartium flaccidum, Winter, Krypt.-Flora, i. p. 236. —
Uredospore sori forming pustules, minute, ochraceous,
or pale brown, pseudoperidium very firm, plano-convex;
uredospores roundish, ovate, piriform, etc., i8-44X 12-20 /x,
aculeate, pale orange; teleutospores forming a cylindric-
oblong, often curved or tortuous column 2 mm. high, pale
brown, teleutospores oblong or cylindrical, ends obtuse,
brown, 8-12 /A diam.

Aecidium condition unknown.

Melampsora, Cast. — Spermogonia forming minute, orbi-
cular, covered patches ; aecidia (Caeoma form), destitute
of a pseudoperidium ; spores in chains ; uredospores pro-
duced singly at the tips of sterigmata, aculeolate, enclosed
in a more or less developed pseudoperidium ; teleutospores
i -celled, obovate-cuneate, compacted into a firm, crustlike,
plane stratum ; sporidiola subglobose, yellow, or orange.

Melampsora pinitorqua, Rost. = J/. populina, LeV.—
Caeoma stage, sori mostly linear, up to 2 cm. long, solitary
or crowded, orange, spores round or polygonal, 15-20 /*,
warted, pale rufous yellow ; uredospore sori rounded, often
bullate and confluent, orange-rufous, spores elliptic or
ovoid, 28-38 x 13-20 ju, aculeate, orange; paraphyses more
or less abundant, up to 50 p long, swollen apex 17-20 /x
broad ; teleutospore sori epiphyllous, flattened, often
confluent, at first rufous-brown, then blackish-brown,
teleutospores 40-45 x 13 /*; sporidiola globose, orange.

Melampsora laricis, Rost, Caeoma laricis, Hartig.—
Melampsora tremula caeoma stage, sori narrow, 500 p. to
5 mm. long, on a yellow spot ; spores round or elliptical,
16-24x12-17 /*, delicately warted, orange-yellow; uredo-
spore sori often expanded on twigs, rufous orange, rounded

4io PLANT DISEASES

on the leaves, spores elliptical or ovoid, I5-24X 13-18 ^u,
aculeate, orange rufous, paraphyses numerous, clavate;
teleutospore sori hypophyllous, very numerous, rufous-
brown at first, then pitch-brown, crustlike teleutospores,
43-55Xn-i2/x.

Melampsora lini, Tul., Ann. Sci. Nat, 1854, p. 93.—
Uredospore sori scattered, covered with a deciduous
pseudoperidium, rotund, orange, minute; spores sub-
globose or obovoid, pedicellate, echinate, 15-24x14-18 /x,
orange-yellow ; paraphyses curved, apex strongly sphae-
roidally or ovoidly incrassated, iy-2o/x; teleutospore sori
flattened, at first rufous-brown, then blackish ; teleutospores
densely packed under the epidermis, cylindrico-prismatic,
45-60 x 1 7-20 /A.

Puccinia, Pers. — Aecidia, spermogonia, and uredospores
as in Uromyces ; teleutospores transversely i-septate, rarely
2-septate, each cell having one germ-pore ; sori flattened or
convex, at first covered by the epidermis of the host;
sporidiola ovoid or reniform, generally hyaline.

* Eupuccinia, Schrot. — Spermogonia, aecidia, uredo-
spores, and teleutospores produced in a living host ;
teleutospores germinating after a period of rest. (Not
on a living host.)

f Auto-Eupuccinia, De Bary. — Spermogonia, aecidia,
uredospores, and teleutospores produced on the same
host.

Puccinia asparagi, D.C.,JF7or.Fr.ii.p. 595. — Spermogonia
in small clusters ; aecidia forming longitudinal lines on the
stem, margin whitish, torn; spores 15-28^, epispore hyaline,
delicately verruculose, contents yellow ; uredospores 20-30
X 17-25 /u, delicately echinulate, pale brown; teleutospores

UREDINACEAE 411

elliptical or elongate-clavate, base rounded, slightly con-
stricted ; apex rounded, 35-52 x 17-26 /x, smooth, chestnut-
brown ; pedicel persistent ; forming elongated blackish sori
on the^stem, rarely on the leaves.

Puccinia menthae, Pers.,S}>n.FuKg., p. 227. — Spermogonia
honey-colour, in little clusters ; aecidia on stem or leaves
forming large, inflated, coloured spots, large, plane, spores
verruculose, pale yellow, 40 x 17-26 /A; uredospores elliptic
or ovoid, aculeate, pale brown, 17-28 X 14-19 /x; teleutospore
sori hypophyllous, rarely on the stem, scattered or aggre-
gated ; spores elliptical, or shortly cylindrical, ends rounded,
scarcely constricted, apex slightly thickened, 26-35 x J9'
23 ft, minutely warted, with a broad, colourless, or pallid
apical papilla, dark brown ; pedicel longer than the spore,
hyaline, slender.

Puccinia hieracii, Mart, Fl. Mosq., p. 226. — Spermogonia
in little groups ; aecidia arranged in rings or without order
on purplish spots, margin broad, white, torn; spores 30 x
16-23 /A, pale yellow, smooth or minutely verruculose; uredo
sori on both surfaces, rounded, scattered, or gregarious ;
spores globose or elliptic, 17-32 x 16-26 //, chestnut-brown,
aculeate, with two or three germ-pores ; teleutospores in
similar sori, crowded, spores elliptic or ovoid, apex rounded,
often narrowed below, very finely punctate, 24-45 * 17-28 /*
brown ; pedicel slender, longish, hyaline, soon deciduous.

ft Hetero-puccinia, Schrot. — The sporidiola do not
infect the same species of host-plant that produces the
teleutospores, but a different one which bears the sper-
mogonia and aecidia.

Puccinia pringsheimiana, Kleb., Zeitschr. f. Pflatizenkr.,
v, p. 79. — Spermogonia honey-yellow, in small groups;

412 PLANT DISEASES

aecidia often forming concentric rings, crowded on rounded,
reddish spots, peridia shortly cylindrical, margin white,
torn; spores 10-20 p, orange; epispore hyaline, scarcely
wrinkled ; teleutospores forming sori on leaves or culms,
elongated, brown, pulverulent, blackish ; spores clavate-
oblong or oblong, apex much thickened, rounded, or
truncate; base often narrowed, smooth, brown, 35-50 X
15-20 fJL ; pedicel rigid, persistent.

Puccinia graminis, Pers., Tent. Disp. Meth. Fung., p. 39,
tab. 3, f. 3 (i797).

i. Diseased spots on the leaves 3-4 mm. diam., centre
red, margin yellowish, sometimes also formed on twigs,
flower, and fruit ; aecidia shortly cylindrical, margin
spreading and torn ; spores subglobose, smooth, yellow,
14-26 //. diam. ; spermogonia on opposite side of leaf to
the aecidia.

n. Sori forming yellowish, rust-coloured streaks 2-3 mm.
long, or sometimes much longer ; uredospores broadly
elliptic, dingy yellow, spinulose, iy-4ox 14-22 /*.

in. Sori forming blackish streaks up to 10 mm. long,
often much shorter ; teleutospores fusiform or club-shaped,
with a long pedicel, slightly constricted at the septum,
smooth, chestnut-brown ; apex rounded or narrowed, with
the wall thickened, 35-60 X 12-22 p.

Puccinia coronata, Corda, Icon. Fung., i. p. 6, tab. 2,
f. 96.

i. Aecidia on irregular yellow patches on the under
surface of the leaves, especially along the nerve ; also
on the flower-buds and fruit ; aecidiospores spinulose,

18-25 X 14-19 p-

ii. Sori orange-red, narrow, and elongated, mostly on the

UREDINACEAE 413

upper surface of the leaf, rarely on the leaf-sheath, culm,
or glumes ; uredospores globose or broadly elliptic,
spinulose, yellow, 20-32 //, or 21-32 X 20-24 /A.

in. Sori blackish, small, numerous, often forming rings
on the leaf, surrounded by brown paraphyses ; teleutospores
shortly stalked, mostly clavate, apex truncate, with a
variable number of processes of variable length, 25-57 p
long, basal cell 8-19 /x wide, terminal cell 10-19 //. wide.

Puccinia dispersa, Eriksson and Henn., Getreidr., p. 210,
tab. x., xi., figs. 119-123.

i. Aecidia forming large orange patches on stem, leaves,
and calyx ; aecidiospores spinulose, 20-30 /x- diam., or
20-30 X 19-22 fj..

ii. Sori small, i mm. long, and nearly as broad, crowded
in groups on the leaves, ochraceous brown; uredospores
globose or broadly elliptical, spinulose, yellow, 19-29 /x
diam.

in. Sori blackish, irregularly scattered on the under
side, rarely on the upper side of the leaf, each sorus
surrounded by curved, brown paraphyses ; teleutospores
shortly stalked, mostly elongate club-shaped, unsym-
metrical, 40-50 /A broad, terminal cell 14-19 p broad;
promycelium colourless.

Puccinia glumarum, Eriksson and Henn., Getreidr., p.
141, tab. v.-ix., figs. 52, and 57-108.

i. Unknown (wanting?).

ii. Sori minute, yellow-brown, densely crowded on the
leaves, more scattered on the inner surface of the glumes ;
uredospores globose or shortly elliptical, spinulose, yellow,
25-30 /A diam.

Hi. Sori forming crowded, blackish streaks on the leaf-

414 PLANT DISEASES

sheaths, more scattered on the inner surface of the glumes;
each sorus encircled with curved, brownish paraphyses;
teleuto-spores shortly stalked, mostly elongated, club-
shaped, unsymmetrical, apex flattened or with 1-2 blunt
prominences, 30-40 fj. long, basal cell 9-12 //, wide, terminal
cell 16-24 fj. wide ; promycelium contents yellow.

Puccinia simplex, Eriksson and Henn., Getreidr., p. 238,
tab. xi., figs. 124-128.

i. Unknown (absent?).

n. Sori very minute, up to 0-5 mm. long, sparingly
scattered on the upper side of the leaves, citron-yellow;
uredospores globose or shortly elliptical, spinulose, yellow,
19-22 ^ diam., or 22-27 X I5~I9 P-

in. Sori very minute, blackish, scattered on the leaves,
somewhat longer on the leaf-sheath, each sorus with brown
paraphyses ; teleutospores stipitate, mostly i-celled, un-
symmetrical, 24-30X16-18 /A, rarely 2-celled, clavate, apex
blunt or narrowed, 40-48 /* long, basal cell 16-18 //- broad,
terminal cell 19-24 //, broad.

Puccinia phlei-pratensis, Eriksson and Henn., Getreidr.,
p. 130, tab. v., f. 55, 56.

I. Unknown (absent?).

ii. Sori often crowded, yellowish brown, 1-2 mm. long,
on leaf-sheaths and culm ; uredospores oblong, pear-shaped,
spinulose, dirty yellow, 18-27 x 15-19 P-

in. Sori blackish, on leaf-sheath and culm, 2-5 mm. long ;
teleutospores fusiform or club-shaped, constricted at the
septum, chestnut-brown, apex rounded or narrowed, wall
much thickened, 38-52 x 14-16 //.

** Brachypuccinia, Schrot. — Sperm ogonia, uredospores,

UREDINACEAE 415

and teleutospores produced on the same host-plant ; aecidia
not produced.

Puccinia bullata, Schrot., Rilze Schles., p. 335. — Sper-
mogonia honey-colour, arranged in rounded groups ;
uredospores irregularly globose, aculeate, ochraceous-
brown, apex incrassated, 23-38x20-26 ft, with two lateral
germ-pores, shortly pedicellate ; teleutospores deformed,
slightly constricted at the septum, both ends rounded,
rarely narrowed at base or apex, smooth, brown, apex
thickened, 30-56X17-28 ft; pedicel deciduous, slender,
longish.

*** Hemipuccinia, Schrot. — Uredospores and teleuto-
spores produced on the same host ; spermogonia and
aecidia unknown.

Puccinia tanaceti, D. C, Flor. France, ii. p. 222.—
Uredo sori hypophyllous, scattered, erumpent, orbicular,
plane, very minute, brownish, crowded, spores elliptic or
ovate, 19-35 X 16-25 V"> muricato-aculeate, ochraceous ;
teleutospores forming sori on both sides of the leaf,
blackish, pulvinate, erumpent, orbicular, scattered, or
crowded, spores elliptical or clavate, apex much thickened,
cells almost equal, constricted at the septum, 32-60 x 17-28
ft, smooth or apex punctulate, chestnut-brown ; pedicel
hyaline, up to 100 ft long.

Puccinia pruni, Pers., Syn. Fung., p. 226. — Uredospores
hypophyllous, sori minute, orbicular, confluent, cinnamon-
brown, 10-35X10-18 fit spinulose, sessile, apex generally
thickened ; paraphyses numerous ; sori of teleutospores
hypophyllous, scattered or confluent, plane, brown ; spores
oblong formed of two globose cells, lower one generally
smallest, 28-45x17-24 ft, covered with aculeate warts,

416 PLANT DISEASES

brown, pedicel short, hyaline, deciduous ; paraphyses
numerous, brown.

**** Leptopuccinia, Schrot. — Teleutospores only known,
generally in compact, crowded, pulvinate sori germinat-
ing on the living host ; sori often powdered with the
whitish or rufescent sporidiola.

Puccinia malvacearum, Mont, Gay's Hist.fis.y. polit. de
Chile, viii. p. 43. — Hypophyllous, sori hemispherical, hard,
gregarious, small, brown ; teleutospores ovoid-oblong, 35-75
X 1 2-26 p, fuscous, smooth, slightly constricted at the
centre, obtuse or acuminate, pedicel very long ; up to
120 /*, hyaline.

Puccinia arenariae, Schrot., Pilze Schles., p. 345.—
Teleutospore sori rounded, pulvinate, often arranged in an
orbicular manner or in elongated crusts, pale brown, then
blackish-brown, often becoming pulverulent and greyish
from the sporidiola ; spores fusoid or clavate, apex rounded
or conoidly incrassated, slightly constricted, base narrowed,
ochraceous-brown, smooth, 30-50 X 10-20 /*; pedicel hyaline,
equal or longer than the spore, persistent.

Gymnosporangium, Hedw. — Teleutospores forming large
subgelatinous masses distinct from the substratum, rarely
forming small, adnate, convex patches, transversely
i-septate, very rarely biseptate, each cell with 2 or 4
germ-spores.

All known species have spermogonia and aecidia on
one host, teleutospores on another distinct host; uredo-
spores unknown.

Gymnosporangium sabinae, Winter, Krypt.-Flora, i.
p. 232. — Spermogonia rufous-orange, then black, conoidly

UREDINACEAE 417

prominent, epiphyllous, rarely on fruit or branches, rather
large, in small groups on yellow or rufescent spots ; sporules
minute, pale orange; aecidia hypophyllous, opposite the
spermogonia, forming large, convex tubercles, numerous,
yellowish, ventricose, 2 mm. long, 1-1-5 mm- broad, apex
closed, sides perforated or subcancellate ; aecidiospores
in chains, 22-44X17-26, brownish, angularly rounded,
delicately warted ; sori of teleutospores irregularly conoid
or cylindrical, obtuse, sometimes compressed or branched,
yellowish-rufous, gelatinous, 8-10 mm. long; teleutospores
ellipsoid 38-50X23-26 /A; scarcely constricted at the
septum, chestnut-brown, each cell having four germ-pores.

Gymnosporangium juniperinum, Fries, Syst. Myc., iii.
p. 506. — Spermogonia epiphyllous, rather large, sub-
prominent, conoid, brownish-orange, in small groups on
yellowish or orange spots; pseudoperidia hypophyllous,
aggregated, tubular, cylindrical, very long (up to 8 mm.
long and i mm. wide), seated on orange spots, incurved,
whitish, then yellowish, margin denticulate, spreading;
aecidiospores in chains, angularly spherical, brownish-
yellow, 20-28X10-24 /*, delicately verruculose, with six
germ-spores ; sori of teleutospores simple or caespitose,
subgelatinous, hemispherical or conoid, tawny, becoming
swollen, orbicular, piriform, etc., in damp weather, golden,
finally wrinkled and collapsed ; teleutospores ellipsoid or
oblong, ends attenuated, 40-75X17-27 /a, not constricted
at the septum, slightly tinged brown, pedicel very long.

Gymnosporangium clavariiforme, Rees, Wint., Krypt.-Fl.^
i. p. 233. — Spermogonia epiphyllous or fruticolous, erump-
ent from a thickened, orange or yellow patch, spermatia
yellow, oblong; pseudoperidia springing from coloured

2 D

4i8 PLANT DISEASES

spots like the spermogonia, gregarious, cylindrical, whitish,
splitting from apex to base into reflexed filaments, aecidio-
spores war ted, catenulate, yellowish, 22-45x19-35 p',
teleutospores oblong-fusoid, i-septato, not constricted,
yellow, 90-120X15-18 /A, with very long, slender, hyaline
pedicels, forming subgelatinous, elongato-clavate, com-
pressed, simple or bifid, yellowish-orange masses about
i cm. long, or sometimes longer.

Gymnosporangium confusum, Plow., Brit. Ured. and
Ustilag.^. 232. — Pseudoperidia on thickened, reddish spots,
orange above, and often surrounded by a reddish or purple
line, cylindrical, or cylindric-fusiform, opening by lateral,
longitudinal fissures, at length fimbriate ; spores sub-
globose, pale brown, 15-20 //, diam. ; teleutospore
mycelium perennial; spore-masses vernal, at first tuber-
culate, dark chocolate-brown, almost black, soon becoming
cylindrical, often compressed, 5-8 mm. long, then rich
chestnut-brown, swelling when moist, and speedily covered
with golden-yellow promycelium spores ; spores smooth,
oval, or elliptical, generally acute at both ends, of two
kinds, the more numerous with hyaline walls and orange-
yellow contents, the other with dark brown, thick walls,
40-50X20-25 /u,, with from 2-4 germ-tubes; pedicel long,
80-100 p, hyaline.

Phragmidium, Link. — Spermogonia flattened, orbicular;
aecidia (Caeomd) in roundish clusters, confluent, and
broadly effused ; aecidiospores in chains ; uredospores
formed singly at the tips of hyphae ; teleutospores trans-
versely 3-many-septate, upper cell with i germ-spore, the
remainder with 4 germ-spores each.

Phragmidium rubi-idaei, Karst, Myc. Fenn. Hypoderm^

UREDINACEAE 419

p. 52. — Aecidia generally hypophyllous, rarely on petiole or
stem, in chrome-yellow, orbicular groups having the centre
depressed, or forming oblong pustules on petiole and stem ;
aecidiospores aculeolate, orange-yellow, 20-28 ft ; paraphyses
clavate, orange; uredospore sori minute, scattered or
circularly arranged, yellow, spores aculeate, orange, 16-22 ft ;
teleutospore sori hypophyllous, minute, black ; teleutospores
oblong, apiculate, warted, 5-io-septate, black, opaque,
90-140X20-35 ft, pedicel slightly incrassated below,
uo-i6oX 17-20 ft.

Phragmidium subcorticatum, Winter, Krypt.-Fl.^.^. 228.
— Aecidia hypophyllous, effused, various in form, often
confluent, reddish-orange becoming pale, large, aecidio-
spores irregularly globose; epispore hyaline, contents orange,
aculeolate, 1 7-28 X 12-20 ft; uredospore sori soon naked,
hypophyllous, scattered or crowded, on pale spots, orbicular,
yellow, minute ; uredospores variable in form, 17-32 x 12-24
ft, delicately aculeolate; teleutospore sori hypophyllous,
scattered or aggregated, orbicular, black, minute ; teleuto-
spores oblong, obtuse with a white apiculus, 3-8-septate,
verrucose, dark brown, 75-100X26-30 ft, pedicel 100-120 ft
long, thickened in the middle up to 22 ft.

Coleosporium, Lev. — Spermogonia and aecidia developed
on leaves of conifers ; uredospores at first grouped in
moniliform series, orange or yellow, echinulate; teleuto-
spores transversely 3 to many-septate, forming a flat, some-
what mucous, orange or yellow, flat layer, closely compacted,
on living host plant ; sporidiola large.

Coleosporium senecionis, Fr., Summa Veg., p. 512. —
Spermogonia scattered ; aecidia of two forms, one solitary
or few in number, on the leaves, cylindrical, up to 2^5 mm.

420 PLANT DISEASES

long ; others on the bark, often 6 mm. broad, saccate, torn,
crowded, white, spores various in form, up to 40 X 17-28 /*,
warted, orange ; sori of uredospores yellowish-rufous, soon
pale, pulverulent ; spores in short chains, soon separating,
elliptical or subcylindrical, orange, warted, 20-40 X 14-26 p;
sori of teleutospores forming waxy, slightly convex crusts,
yellowish-rufous then red, spores cylindrical or cylindric-
clavate, up to 110X17-35 /*•, apex flattened, generally
4-celled, bright rufous-orange.

Chrysomyxa, Unger. — Teleutospores transversely many-
septate, arranged in a single series, or sometimes branched,
lower loculi sterile, coalescing in a yellow or reddish,
somewhat waxy, flat or slightly convex stratum ; pro-
mycelium generally 4-septate, each cell producing a
single secondary spore on the apex of a slender sterigma ;
uredospores as in Coleosporium ; aecidia as in Pucdnia.

Chrysomyxa rhododendri, De Bary, Bot. Ztg., 1879,
p. 809, t. x., f. 1-6. — Aecidia on yellowish spots, in 1-2
rows on the needles ; pseudoperidia cylindric, margin torn,
white, up to 3 mm. long, cells much compressed; aecidio-
spores variable in form, 17-45x12-22 //,, warted, orange-
yellow; uredospore sori rounded, oblong, or angular,
scattered or gregarious, on variously coloured spots ; uredo-
spores generally subpolygonal, globose, or oblong, I7-28X
15-22 /x, warted, orange-yellow ; teleutospore sori convex,
irregularly arranged in large or small groups on reddish-
brown spots ; teleutospores 10-14 /"* broad, not dilated
upwards, obtusely rounded.

Chrysomyxa abietis, Unger, Beitr. zur VergL PathoL,
p. 24, fig. — Sori of teleutospore stage (hybernating mycelium)
linear, seriate, waxy, reddish-yellow, seated on yellowish

UREDINACEAE 421

spots ; teleutospores cylindrical, slightly clavately thickened
upwards, often branched, up to 100 p long, and 9-12 //.
broad, having up to 12 cells; epispore hyaline, contents
reddish-orange; secondary spores globose, 4-6 /*, rufous-
orange.

Aecidium, Pers. — Pseudoperidium cupulate or sub-
urceolate, rarely cylindrical, generally pale-coloured, margin
often crenate or laciniate and revolute; aecidiospores
globose or angular, continuous, most frequently orange-
yellow, catenulate, smooth, or verrucose.

Uredo- and teleutospore conditions, if present, not
correlated with the Aecidium.

Aecidium magelhaenicum, Berk., Hook., FL Antart., ii.
p. 450. — Aecidia generally scattered over the entire under
surface of the leaf, cylindrical, whitish, margin incised;
spores polygonal, 20-40X16-24 /u, epispore hyaline,
verruculose, contents orange.

Aecidium ornamentale, Kalchbr., Flora, 1876, p. 362.—
Aecidia very numerous, occupying the entire surface of the
branch, pale flesh-colour, concave or often obconic, or
narrowly cylindrical, margin slightly torn ; spores angularly
globose, orange-red.

Aecidium esculentum, Barcl. — Pseudoperidia gregarious,
immersed, conoid, for a long time closed, i mm. diam. ;
spores very abundant, in long series, subcuboid, 28-40 x
16-19 /x; spermogonia minute, depressed, superficial,
100-120 \L diam., 30-40 p high.

Aecidium strobilinum, Rees, Rostp., p. 105. — Aecidia
densely gregarious, numerous, generally covering the inner
surface of cone scales, brownish, hemispherical, or polygonal

422 PLANT DISEASES

from mutual pressure, up to i mm. diam., dehiscing in a
circumscissile manner; aecidiospores 18-35X16-22 //,,
epispore hyaline, contents yellowish rufous, then pale.

Aecidium pseudo-columnare, Kiihn, Hedw., 1884, p. 168.
— Aecidia hypophyllous, 2-seriate, discolouring but not
deforming the leaves, 0*5-2 mm. high, margin irregularly
torn, whitish; spores variable in form, 22-37x18-26 /*,
whitish, delicately verruculose.

Peridermium, Lev. — Pseudoperidia growing on bark,
cone scales, or leaves, erumpent, saccate or tubular, apex
torn ; spores in chains, becoming free, globose or elliptical ;
epispore hyaline, warted or reticulated, contents orange ;
spermogonia truncato-conoid.

Peridermium harknessii, Moore, in Ellis and Harkn,,
Calif. Fungi, p. 17. — Pseudoperidia crowded, irregular,
large, growing all round the branch ; aecidiospores irregular
in form, orange, at length whitish, 35-40 //, diam., very
minutely echinulate.

Peridermium orientale, Cke., Indian Forester, iii. p. 91.
— Pseudoperidia solitary or scattered, large, for a long
time closed and triquetrous, at length opening at the apex,
orange-rosy; spores generally subglobose or broadly
elliptical, very uniform, orange, 15-18x10-12 /*, epispore
thin, densely verruculose.

Peridermium coruscans, Fries, Summa Veg. Scand.,Tp.$io.
— Pseudoperidia numerous, longitudinally arranged, at first
closed, ellipsoid, then membranaceous, elongated, whitish,
tubular, apex divaricating, pale red ; spores usually globose,
orange-yellow, 30-35 x 20-24 /*, epispore thin, obsoletely but
very densely verruculose.

Peridermium conorum, Thiim., Mon., p. 313. — Aecidia

UREDINACEAE 423

more or less covering the outer surface of cone scales ;
spores oblong-polyhedric, about 24-33X18-22 //., warted,
areolate, orange-yellow.

Peridermium elatinum, Kze. and Scbw., D. Schw.,
No. 142. — Spermogonia immersed, conoidly prominent,
honey-colour; aecidia hypophyllous, in 1-2 rows, white,
irregularly torn; spores elliptic or polygonal, 16-30 X 14-17
/x, epispore hyaline, coarsely warted, contents orange.

Uredo, Pers. — Sori generally orange-yellow, subpul-
verulent, superficial or erumpent, pseudoperidium absent ;
uredospores formed singly at the tips of fertile hyphae.

Uredo vitis, Thiim., Die-Pilze des Weinstockes, p. 182.
Sori hypophyllous, usually minute and more or less
crowded, bright yellow, resembling minute aecidia under a
lens, due to the elevated margin composed of paraphyses ;
spores piriform or broadly elliptical ; epispore thin, minutely
verruculose, colourless, contents orange-yellow, i8-3ox
15-18 /A; paraphyses colourless, cylindrical, slightly curved,
33-35 X 7-9 P-

Uredo cannae, Wint, Hedw., 1884, p. 172. — Sori
generally hypophyllous, rarely also epiphyllous, without
spots, either densely scattered over the entire surface, or
collected in groups, minute, pale yellow, for a long time
covered by the epidermis; spores variable in form,
yellowish, echinulate, 25-45 X 16-23 p.

SPHAEROPSIDIACEAE

Fungi with perithecia containing conidia borne at the
tips of slender conidiophores ; asci absent.

Probably representing phases in the life-cycle of asciger-
ous fungi.

424 PLANT DISEASES

Phyllosticta, Pers. — Perithecia formed under the epi-
dermis, lenticular, membranaceous, mouth or pore of
dehiscence often protruding, seated on discoloured spots
on leaves, rarely on branches. Conidia minute, ovoid or
oblong, continuous, hyaline or tinged greenish-yellow.

Phyllosticta prunicola, Sacc., Mich., i. p. 157. — Spots
epiphyllous, subcircular, dingy brown or ochraceous,
margin similarly coloured ; perithecia scattered, dotlike,
slightly prominent ; spores ovoid or elliptical, dilute olive,

On leaves of Prunus domesticus. P. cerasus, and Pirus
malus, also on various cultivated rosaceous fruit-trees.
Distr. — Western Europe, United States.

Phoma, Fries. — Perithecia subcutaneous, then erump-
ent, membranaceous, subcoriaceous, or subcarbonaceous,
globose or compressed, glabrous, not beaked, ostiola
minute, sometimes obsolete ; conidia hyaline, continuous,
often 2-guttulate, elliptical, cylindrical, fusoid or globose;
conidiophores slender, usually simple.

Phoma rostrupii, Sacc., SylL, xi. 490 ; Phoma sanguino-
lenta, Rostrup, Zeitschr. f. Pflanzenkr., iv. p. 195, pi. 4.
(1894). — Perithecia hemispherical, gregarious, or crowded,
greyish-black; conidia elliptical, 4-6x1*5-3 i*> oozing out
of the mouth of the perithecium in damp weather in the
form of a long, curved, blood-red or violet-red tendril.

Phoma sanguinolenta, Rostrup, Tidssk. for Landok v.
Rackke., Bd. vii. p. 384 (1887). — Perithecia gregarious on
depressed areas on the stem, or causing large cankerlike
depressions on the root ; conidia 4-6 X i '5-3 /*, escaping
in the form of a flesh or blood-red tendril.

.) the carrot (Daucas Carota\ Europe, United States.

SPHAEROPSIDIACEAE 425

Phoma hennebergii, J. Kiihn, Hedw., 1877, p. 121. —
Perithecia scattered on brown spots, erumpent, rounded,
black, TOO /*diam. ; conidia cylindrical, continuous, some-
times slightly curved, 14-18X2-2-5 /A, hyaline.

Hab.t Paleae and leaves of Triticum sativum, Germany,
Denmark.

Vermicularia, Fries. — Perithecia erumpent or subsuper-
ficial, membranaceo-carbonaceous, black, globoso-conical,
at length concave, apex perforated or mouthless, clothed
with long, rigid, septate, fuliginous hairs ; conidia typi-
cally cylindric-fusoid, often inaequilateral, continuous,
borne on variously formed basidia.

In some species the perithecium is imperfect or pezizoid.

Vermicularia circinans. Berk., Gard. Chron., 1851, p.
595. — Spots orbicular, perithecia concentrically arranged,
seated on radiating, hyaline, septate mycelium, very
minute, furnished with long, rigid hairs; conidia oblong,
obtuse, 2 -many-nucleate, hyaline, 10-14x3-4 p.

Fusicoccum, Corda. — Stroma subcutaneous, erumpent,
black, internally divided into several cells or cavities, the
walls of which are lined with spindle-shaped, continuous,
straight conidia.

Differs from Cytispora in the larger, fusiform conidia.

Fusicoccum abietinum (Hartig), Prill, and Dela., Bull.
Soc. Myc. France, Feb. 1890; Sacc., Syll., x. p. 241. —
Stromata black, conical, subgregarious, apex piercing the
tumid cortex, 400-600 //. diam. pluricellular within; conidia
hyaline, fusoid, ends acute, straight, pluriguttulate, 12-14
X 5-6 /x ; conidiophores acute, 10-15 X 1*5-2 /*.

In living bark of Abies excelsa.

Distr. — Germany, France.

Quite distinct from Dothiorella pitya, Sacc.

426 PLANT DISEASES

Ascochyta, Lib. — Perithecia generally gregarious on dis-
coloured patches on leaves or branches, membranaceous,
innate, an apical mouth or pore protruding, compressed-
globose; conidia elliptical or elliptic-oblong, i-septate,
hyaline or tinged greenish-yellow.

Ascochyta pisi, Lib., Ex. PL Ard., No. 12. — Spots
subrotund, yellowish with a darker margin, perithecia
gregarious, brown, ostiolum protruding ; conidia oblong,
hyaline, i-septate, 14-16x4-6 /A; extruded in reddish
viscid tendrils.

Septoria, Fries. — Perithecia subcuticular, globoso-lenti-
cular, furnished with a pore, laxly membranaceous, typi-
cally developed on decoloured areas on leaves ; conidia
rod-shaped or filiform, pluriseptate or pluriguttulate, rarely
eguttulate, hyaline ; basidia minute.

Septoria petroselini, Desm., Crypt. France, £xs., No.
674. — Spots brown, then white, determinate, on both
surfaces; perithecia minute, delicately membranaceous,
perforated, lenticular, parenchymatous, olive; conidia
filiform, straight or flexuous, 6-io-guttulate or delicately
septate, hyaline, 3 5-40 x 1-2 ft.

Entomosporium, Lev. — Perithecia hemispherico-appla-
nata, mouthless, black (spurious ?) ; conidia consisting of
two superposed cells, with two or more cells springing
from the median septum, all the cells setigerous.

Entomosporium maculatum, Lev., in Moug. Stirp. Vog.,
No. 1458. — Perithecia epiphyllous, flattened, imperfectly
ostiolate ; conidia 4-celled, 18-20X12 /x., hyaline, lateral
cells smaller, depressed, with very long setae ; pedicel
filiform, 20 X i /*.

MELANCONIACEAE 427

MELANCONIACEAE

Perithecia and asci absent; conidia produced on a
more or less developed cushion or stroma formed beneath
the surface of the matrix, and becoming erumpent

Probably forms of higher species.

Gloeosporium, Desm. — Sporodochium formed below
the epidermis of the host, discoid or pulvinate, at length
often erumpent, pallid or brown ; conidia ovate-oblong,
rarely oblong, hyaline, continuous, often extruded in
the form of a sphere or tendril consisting of the conidia
held together by mucilage; basidia usually acicular, fas-
ciculate.

Gloeosporium nervisequum, Sacc., Mich., ii. p. 381.—
Pustules hypophyllous, erumpent, slightly prominent, brown,
then black, seated on brown, dry patches of the leaf, most
frequently following the larger veins, but sometimes form-
ing broad patches; conidiophores slender, 12-15x4-6/4;
conidia oblong-ovate or pear-shaped, hyaline, 12-15 x 5"6 /*•

On living leaves of Platanus orientalis, P. occidentalis,
also other species of Platanus, and said to occur on oak
leaves in the United States.

Distr. — Europe, United States.

Gloeosporium ribis, Mont, and Desm. in Kickx1 FL
Crypt. Fland., ii. p. 95. — Spots minute, rounded, often con-
fluent, brown ; pustules epiphyllous, blackish, flattened ;
conidia hyaline, oblong, curved, apex obliquely pointed,
10-12 X 5-6 p.

On living leaves of Ribes nigrum, R. rubrum, R. aricu-
lare, and R. grossulariae.

Distr.— Europe, Asiatic Siberia, Australia, United States.

428 PLANT DISEASES

In the American form on tf. nigrum the conidia are
larger, equal at both ends, 15-25 p long. An apparently
distinct var. or species.

Gloeosporium venetum, Speg., Mich., i. p. 477. — Spots
yellowish or ochraceous, small and rounded, or larger
and irregular towards the margin of the leaf, and sur-
rounded by a dusky purple line ; pustules minute, promi-
nent, solitary or gregarious ; conidia elliptico-cylindrical,
hyaline, contents granular and guttulate, 7-8X2-2*5 //..

On living leaves and stems of Rubus chamaeodorus and
R. idaeus.

Distr. — Europe, North America, Australia.

Gloeosporium ampelophagum, Sacc., Mich., i. p. 217. —
Spots or pustules subcircular, often confluent, blackening,
drying, and hardening the cortical strata of grape berries,
centre of spots greyish or rosy-primrose, due to the presence
of the extruded conidia ; pustules originating beneath the
epidermis, minute, densely gregarious, stroma thin, pul-
vinate, pallid, prosenchymatous, component cells minute,
the superficial ones shortly apiculate and bearing the
conidia; conidia oblong, ellipsoid or ovate, 5~6X3'5 /*,
2-guttulate, hyaline.

Gloeosporium fructigenum, Berk., Gard. Chron., 1856, p.
245. — Pustules concentric, dingy rose- red, erumpent through
a simple or laciniate pore, pulvinate ; conidia oblong or
cylindrical, often curved, 20-30X5-6 /x, hyaline; basidia
subequal in length, simple, rarely furcate, continuous.

Gloeosporium musarum, Cke. and Mass., Grev., xvi.
p. 3. — Pustules innate, erumpent, gregarious, with a rosy
tinge; conidia elongate ellipsoid, ends rounded, continu-
ous, hyaline, 10-12X4-5 /*, contents granular.

MELANCONIACEAE 429

Gloeosporium rhododendri. — Briosi e Cavara, Fung.
Par., No. 198. — Spots very large, irregular, dry, zoned;
pustules black, rugulose, shining, concentrically arranged
with a black bounding line; conidia cylindric-oblong,
straight or slightly curved, ends obtuse or obliquely trun-
cate, 15-20X4-5 p.

Colletotrichum, Corda. — Acervuli innato-erumpent,
plane, discoid or elongated, black, surrounded by long,
blackish setae; conidia tereti-fusoid, continuous, hyaline,
springing from the tips of short, fasciculate conidiophores.

Colletotrichum lindemuthianum, Briosi e Cavara,
Piante Dan. Exs.> No. 50. — Forming spots on the
epicarp, rarely on stem or leaves, subrotund, dry, and
brownish, at first bounded by a red line ; conidiophores
bursting through the epidermis in tufts on the diseased
spots, fasciculate, cylindrical, simple, 45-55 p long; conidia
acrogenous, oblong, straight or curved, ends rounded,
I5'I9><3*5'5'5 fr hyaline; spines few in number, or^some-
times apparently absent.

Colletotrichum spinaciae, Ellis and Halst.. Journ.
1890, p. 34. — Maculicolous, spots round, dirty-white or
greenish, 2-4 mm. diam., with a slightly raised border ;
acervuli on both sides, punctiform, 40-75 p in diam.,
clothed with a few (3-12) erect or spreading bristle-like
hairs 60-75 //. long x 4-4*5 p thick at the sub-bulbous base,
hyaline and subacute above, dark brown below, continuous
(or faintly septate ?) ; conidia subfalcate-fusoid, hyaline,
2-4 nucleate, 14-20 x 2^5-3 /*, ends subacute, basidia short.

Colletotrichum althaeae, Southw., Journ. Myc., 1890,
p. 46, pi. iii. — Epiphyllous and caulicolous, erumpent,

430 PLANT DISEASES

forming brown spots on the leaves, and light yellowish-
brown to black sunken spots on the petiole and stalk;
spores irregularly oblong, hyaline, flesh-colour in the mass,
11-28x5 p; conidiophores colourless, cylindrical; setae
dark brown, abundant, once or twice septate, usually
colourless below, 60-109X3-5 /*.

Colletotrichum gossypii, South w., Journ. Myc., 1890,
p. 100, pi. iv. — Sori orbicular, dark-coloured, or covered
with a pink powder ; acervuli erumpent ; conidia irregularly
oblong, usually with a lighter spot in the centre, often
acute at one end, colourless singly, flesh-coloured in mass ;
conidiophores colourless, varying in length, at least longer
than the mature spore, produced on a stroma ; setae single
or in tufts, dark brown at base, nearly colourless at the
apex.

Cylindrosporium, Unger. — Pustules or nuclei formed
under the epidermis, white or pallid, discoid or subeffused ;
conidia filiform, continuous, hyaline, often flexuous.

Considered as conidial forms of species of Entyloma.

Cylindrosporium chrysanthemi, Ellis and Dearn., Can.
Rec. Sd.j 1893, p. 271. — Spots rather indefinite, i cm.
and more broad, becoming blackish ; pustules innate, on
both surfaces, 100-170 /A .diam. ; conidia fusoid, almost
straight, 50-100X3-4*5 fa at length escaping.

Cylindrosporium padi, Karsten, Symb. Myc. Fenn.t
pt. xv. p. 159. — Forming angular, brownish spots on both
sides of the leaf; pustules hypophyllous, covered by the
inflated epidermis; conidia filiform, flexuous, hyaline,
eventually appearing at the surface, 48-62 x 2 p.

Libertella, Desm. — Acervuli or conidia masses of various

MELANCONIACEAE 431

form, for a long time covered by epidermis, which is
eventually ruptured, the conidia usually escaping in the
form of mucilaginous tendrils, bright-coloured or pallid ;
conidia slenderly fusiform, elongated, continuous, hyaline.

Libert ella ulcerata, Massee (sp. nov.). — Pustules gre-
garious, numerous, minute, eventually rupturing the epi-
dermis, the conidia being extruded in the form of pale-
coloured, viscid tendrils; conidia fusiform, ends acute,
continuous, curved, hyaline, 55-60X4 /*.

Melanconium, Link. — Pustules or nuclei subcutaneous,
conoid or discoid, black; conidia produced singly at the
tips of basidia, globose or oblong, continuous, fuliginous,
often extruded as viscid masses or tendrils.

Melanconium pandani, Lev., Ann. Set. Nat., Bot., 1845,
p. 66. — Acervuli erumpent, large, black, conoid, often
aggregated in black, warty lines, 1-2 mm. diam. ; conidia
oozing out in black tendrils or irregular masses, pale olive,
elliptic, oblong, straight or slightly bent, often 2-guttulate,
size variable, 5-9 X 3-4 /*; conidiophores elongated, branched,
curved.

Described from a portion of Leveille's specimen, now in
Herb., Kew.

Coryneum, Rees. — Fruit pustules discoid or pulvinate,
subcutaneous, erumpent, compact, black ; conidia oblong
or fusoid, 2-many-septate, fuliginous; basidia filiform.
Conidia never extruded as a viscid tendril.

Coryneum beyerinckii, Oud., Hedw., 1883, p. 113.—
Fruit clusters very minute, dotlike, black, gregarious ;
conidia springing from a brownish, parenchymatous,
pulvinate stroma, crowded, oblong or oblong-obovate, pale

432 PLANT DISEASES

olive, usually 3-septate, very slightly constricted at the
septa, 28-32X11-13 fJ'j conidia slightly thickened below,
hyaline, 28-32X2-3 p.

Pestalozzia, De Notaris. — Pustules subcutaneous, at
length erumpent, discoid or pulvinate, black; conidia
oblong, 2-many-septate, coloured (at least the median
cells), rarely entirely hyaline, apex hyaline, i-many-ciliate,
apical on slender, hyaline basidia.

Pestalozzia guepini, Desm., Ann. Sci. Nat., 1840, vol.
xiii. p. 182, tab. 4, figs. 1-3. — Pustules minute, dotlike,
slightly convex, black, at first covered by the epidermis,
then erumpent, seated on large, bleached spots; conidia
elliptical ends narrowed, 3-4-septate, end cells hyaline,
intermediate ones coloured, terminal cell conoid, terminated
by 3-4 hyaline hairs as long or longer than the conidia,
which are 20-25 /* l°ng; conidiophores slender, hyaline.

Pestalozzia hartigii, Tubeuf, Beitr. Baumkr., p. 40, tab.
5. — Pustules immersed, globose, springing from a- flattened
stroma ; conidia emerging in black masses, at first hyaline,
continuous, then 3-septate, ovate-oblong, the 2 central
cells large, multiguttulate, coloured, terminal cells small,
hyaline, 18-20 //. long, setae 1-4, slender, hyaline, 20 x i /A;
basidia slender, hyaline, 30-50 //, long.

Septogloeum, Sacc. — Pustules growing on living plants,
minute, produced beneath the epidermis, sometimes erump-
ent, pallid; conidia oblong, 2-pluriseptate, hyaline; re-
sembling Gloeosporium, but with septate conidia.

Septogloeum hartigianum, Sacc., in Hartig, Forst
Zeitschr., 1892. — Pustules innato-erumpent, sparsely longi-
tudinally gregarious, oblong-linear, bordered by the

HYPHOMYCETACEAE 433

ruptured periderm, 1-2 mm. long, 0^3 mm. wide, brown,
stromatic base white, producing on its surface the crowded,
parallel, cylindrical with inflated base, hyaline conidio-
phores 30-35x6-7 /A; conidia ovate-oblong, ends obtuse,
almost straight, typically 2-septate, 24-36x10-12 /x, sub-
hyaline.

HYPHOMYCETACEAE

Superficial or subsuperficial, rarely endoparasitic on
insects ; hyphae often profuse, bearing naked, free conidia ;
asci, perithecia, and ascophore absent.

Mostly representing phases in the life-cycle of higher
fungi.

Mucedineae. — Hyphae and conidia hyaline or clear-
coloured ; not brown or blackish.

Oospora, Wallr. — Tufts delicate, effused or pulvinate,
lax or rather compact ; fertile hyphae short, slender, simple,
or sparingly branched; conidia concatenate, globose or
elliptical, colourless or clear-coloured.

Oospora abietum, Oud., Ct. Rend, de FAcad. Roy. d. Sc.
des Pays-Bas, seance de Jan. 1897. — Tufts minute, sub-
pulvinate, forming lines on the leaf near the nerve,
emerging from the stomata ; conidiophores short, simple ;
conidia elliptical, ends rounded, continuous, 10-12x6-7 /*,
caducous.

Oospora scabies, Thaxter, Ann. Rep. Conn. Agric. Expt.
Station, 1891, p. 152. — Vegetative hyphae hyaline or
brownish from the general discoloration of the sub-
stratum, '4- *6 /x, rarely as much as i p, diam., curving
irregularly, septate or pseudoseptate, branching; aerial
hyphae at first white, then greyish, evanescent, breaking

2 E

434

PLANT DISEASES

up into bacteria-like segments, after producing terminal
spirillum-like ' spores ' by the coiling of their free extremi-
ties. Forming a firm, lichenoid pellicle on nutrient jelly,
and usually when growing in contact with the air produc-
ing a deep, black-brown discoloration of the substratum.
Producing the disease known as ' Scab ' on potato tubers,
and a similar affection of beetroots.

The above is the author's amended diagnosis given in
Journ. Mycol., vii. p. 280 (1893). It is stated that the
fungus obtained accidentally from water by Sauvageau, and
described as Oospora metchnikowi (Ann. d. Vlnst. Pasteur,
tab. vi. p. 242) is probably identical with O. scabies.

Monilia, Pers. — Hyphae erect, vaguely branched, often
forming dense tufts, rarely effused, producing denticulate
conidiophores here and there ; conidia rather large, formed
in chains.

Monilia fructigena, Pers., Syn., p. 693.— Tufts compact,
pulvinate, often confluent and forming concentric rings;
hyphae fasciculate, with short branchlets, which bear
simple or branched chains of ovoid, oblong, or lemon-
shaped, hyaline, or pinkish conidia, 25 x 10-12 ^.

Dematiae. — Hyphae or conidia, or both, brown or
blackish.

Fusicladium, Bon. — Hyphae short, straight, sparingly
septate, somewhat fasciculate, olivaceous ; conidia ovoid
or subclavate, for a long time continuous, at length often
i-septate, acrogenous, solitary or in pairs.

Fusicladium pirinum, Fckl., Symb. Myc., p. 357.—
Effused, olive, velvety; conidia ovate-fusoid, 28-30x7-
9 p, continuous (always ?), guttulate, olive ; conidiophores
short, terete, apex denticulate,

HYPHOMYCETACEAE 435

Fusicladium dendriticum, Fckl., Symb. Myc., p. 357.—
Effused, velvety, olive, often epiphyllous, and forming
dendritic patches ; hyphae filiform, fasciculate, erect, 50-
60 X 5 /*, sparingly septate ; conidia apical on the conidio-
phores, fusoid-obclavate, 30 x 7-9 p, for a long time
continuous, at length i-septate, not constricted, olive.

Fusicladium fagopyri, Oud., Ct. Rend, des Seance
Acad. Roy. Sc. Pays-Bas, 1897, p. 88. — Conidiophores
erect, solitary, almost contiguous, straight or flexuous,
sometimes nodulose, continuous or i -septate, olive, 70-80
X 7 p ; conidia apical, solitary, for the most part ovate,
pale olive, continuous or i-septate, 14X9 p.

Acrospeira, Berk, and Broome. — Sterile hyphae decum-
bent, forming a weft, fertile hyphae erect, branched,
septate, tips of branches curved, septate; conidia more or
less globose, warted, produced laterally near the tips of the
curved branches, dark-coloured, as is also the mycelium.

Acrospeira mirabilis, Berk., Intr. Crypt. Bot., p. 305, f.
69A. — Sterile hyphae blackish-olive, floccose, interwoven,
fertile, erect, vaguely branched above, tips of branches
curved and closely septate ; conidia subglobose, lateral near
the tips of the branches, dark-coloured, minutely warted,
15-20 [i diam.

Cladosporium, Link. — Hyphae subdecumbent, branched,
olive; conidia at first subglobose, then elliptical, typically
becoming i-septate, rarely 2-3-septate.

Cladosporium fulvum, Cke., Grev., 1883, p. 32. —
Effused, somewhat felted, tawny ; conidiophores erect-
wavy, septate, nodulose, sparingly branched, tawny ;
conidia elliptical or elliptic-oblong, i-septate, scarcely con-
stricted, pale tawny, translucent, 10-20X4-6 //..

436 PLANT DISEASES

Cladosporium citri, Penzig. — Sporophores tufted, erect,
brown, branched, septate, 30-75X2-4^; conidia fusiform,
dusky, usually continuous, occasionally i-3-septate, 8-9 X
2-5-4 p.

Cladosporium elegans, Penzig, Mich., iL p. 471. — Tufts
epiphyllous, gregarious, distinct, seated on arid spots;
conidiophores erect, fasciculate, simple, sparingly septate,
distinctly sinuous, brown, 160-200X5-6 /x; conidia apical
and lateral, continuous or i-septate, elliptic-oblong,
epispore delicately granulated, pale brown or yellowish,
18-20X5-6 p.

Cladosporium epiphyllum, Mart., ErL, p. 351. — Tufts
arranged in dark olive patches, which are often large and
dense ; hyphae at first erect, then more or less flaccid,
branched and interwoven, pale olive ; conidia very abun-
dant, pale olive, at first continuous then i -septate; pro-
duced in short chains, which sometimes remain attached,
and then the conidium appears large and more than
i-septate, averaging 10-12X4-6 p.

Cladosporium carpophilum, Thum., Fung. Pomic., p. 13.
— Spots orbicular, often confluent, blackish-green, forming
circles ; hyphae short, erect, continuous, slightly branched,
slender, fuscous; conidia ovate, ends obtuse, continuous
or rarely i-septate, 20X5 ^, pale brown.

Helminthosporium, Link. — Conidiophores almost simple,
few septate, often nodulose, oliveaceous, scattered or
usually fasciculate; conidia apical, elongated, cylindrical,
clavate, fusiform, etc., 3-many-septate, epispore smooth,
olive.

Helminthosporium teres, Sacc., Fung. Ital.> tab. 833;
Sacc., Syll.) iv. p. 412. — Spots oblong, on both surfaces,

HYPHOMYCETACEAE 437

olive; conidiophores fasciculate, 100-130X12 /*, cylin-
drical base slightly thickened, fuliginous ; conidia acro-
genous, cylindrical, both ends rounded, straight, 100-115
X 18 /u, 4-5-septate, not constricted, dark olive.

Forma Avenae sativae, Briosi e Cavara, Fung. Par.
Exs., No. 80, differs from type in the conidiophores not
being fasciculate but scattered, 150-200X9-12 /*, and the
slightly smaller conidia, So-noX 15-16 p.

Helminthosporium turcicum, Pass., Boll. Comiz. Agr.
Farm. Ott., 1876; Helminthosporium inconspicuum, Cke.
and Ellis, Grev., vi. 88, pi. 99, f. 17 (1877). — Conidio-
phores gregarious or subfasciculate on large, dry, brownish
spots, 150-180x6-9 /x, few septate, pale olive, apex almost
hyaline, sometimes more or less nodulose ; conidia spindle-
shaped, ends acute, 5-8-septate, pale olive, 80-140x20-
26 [L. Examination of authentic specimens from both
authors enabled me to prove their identity.

Helminthosporium gramineum, Erikss., Bot. CentralbL,
xxix. p. 92 (1887).— Conidiophores solitary, or in clusters
of 2-4, yellowish, i-5-septate, often angularly bent ; conidia
yellowish, straight, elongate-cylindrical, i-5-septate, 50-
100 X 14-20 /z.

Brachysporium, Sacc. — Hyphae rigid, subsimple, brown ;
conidia ovoid or piriform, brown, 2 or few septate, brown.
Often growing on wood.

Distinguished from Helminthosporium by the shorter
conidia ; doubtfully valid.

Brachysporium pisi, Oud., Nederl. Bot. Ver., 1898, p.
527. — Tufts effused, delicate, blackish ; conidiophores
fuliginous, solitary or spuriously caespitose at the base,
septate, smooth, or sometimes torulose near the septa,

438 PLANT DISEASES

100-250 x 5-6 //, • conidia solitary at the apex of the conidio-
phores, elliptical, ends broadly rounded, 3-septate at
maturity, slightly constricted at the septa, pale fuliginous,
28-30X11-12 }JL ; epispore densely and very minutely
echinulate under a high power.

Cercospora, Fresen. — Hyphae somewhat flaccid, simple
or slightly branched, fuscous ; often growing on living
leaves and forming pallid, dry spots ; conidia worm-
shaped, olive or subhy aline, multiseptate.

Cercospora circumscissa, Sacc., Fung. Ven., ser. v. p.
189. — Forming spots on both sides of living leaves; spots
circular, pallid, dry, the dry portion at length falling out;
hyphae fasciculate, nodulose, brownish; conidia acicular,
attenuated towards the apex, septate, tinged brown, 50 x
3 '5-4 /*•

Cercospora apii, Fresen., Beitr., p. 91, pi. xi. figs. 46-54.
— Spots subcircular, on both surfaces, pale brown, 4-6 mm.
diam., with an irregularly narrow raised margin ; hyphae
generally bypophyllous, in minute, brown, gregarious tufts,
i-2-septate, subundulate, 40-60 X 4-5 /^ ; conidia slightly
obclavate, 3-io-septate, 50-80 X4/*, subhyaline.

Cercospora violae, Sacc., Fung. Ven., ser. v. p. 187. —
Forming spots on both surfaces of the leaf; spots sub-
rotund, dry, pallid; hyphae short, simple, 30-35X4 /*,
fuliginous; conidia very long, 150-200X3*5 /*, rod-shaped,
suberect, multiarticulate, hyaline.

Cercospora resedae, Fuckel. — Tufts gregarious, grey,
minute, appearing on dry spots on the leaf, 2-4 mm. diam. ;
hyphae closely crowded, quite simple, continuous or

>

HYPHOMYCETACEAE 439

sparingly septate, straight, slightly tortuous upwards, 50-
70 x 4-5 /*, brown ; conidia acrogenous, narrowly obclavate,
4-5-septate, hyaline, ioo-i4dX 2*5-3 /*•

Cercospora viticola, Sacc., Syll., iv., No. 2200. — Spots
appearing on both surfaces of the leaf, subcircular or
irregular, 2-10 mm. diam., often numerous and growing
into each other ; hyphae often hypophyllous, in densely
fasciculate tufts, filiform, septate, 50-200X4-5 /*, straight,
ochraceous, apex obtuse and obsoletely denticulate ;
conidia elongate-obclavate, narrowed upwards, 3-4-septate,
guttulate, 50-70 X 7-8 p, ochraceous-olive.

Cercospora beticola, Sacc., Fung. Ven.^ ser. v. p. 189. —
Forming spots on both surfaces of the leaf; spots vague in
form, dry, 2-3 mm. or more across, often bordered with
red ; hyphae fasciculate, often continuous, cylindrical, 40-
50x4-5 ^, brownish, apex nodulose ; conidia acicular, 70-
120X3 /^, densely and delicately septate, hyaline.

Heterosporium, Klotzsch, Herb. Myc., i., No. 67 (1832).
— Conidiophores fasciculate, simple or sparingly branched,
septate, often nodulose, olive-brown ; conidia solitary or in
chains of two or three, cylindric-oblong, 2-5-transversely
septate ; epispore minutely warted or granular, pale olive,
springing from the apex of the conidiophores.

Growing on branches, twigs, and leaves ; often forming
blackish-olive, velvety patches. Helminthosporium only
differs from the present genus in the conidia having the
epispore smooth.

Heterosporiura echinulatum, Cke. — Clusters small, often
numerous, seated on brown spots usually on the upper

440 PLANT DISEASES

surface of the leaf; conidiophores, springing from a small
stroma, 100-200x8-10 /*, olive, septate, nodulose; conidia
terminal or lateral near the apex of the conidiophores,
olive, minutely warted, 2-5 septate, cylindrical, constricted
at the septa, 30-50 x 10-15 /*.

Heterosporium gracile, Sacc., Syll.t iv., No. 2308. — Form-
ing rather large, elliptical, or roundish brown spots bounded
by a darker line; conidiophores septate, nodulose, olive,
70-90 X 10-14 /z; conidia elliptic-oblong, i-3-septate, obtuse
at the ends, minutely warted or granular, pale olive, 35-
70 x 14-20 /A.

On living leaves of species of Iris, Freesia, Antholyza,
and Hemerocellis.

Distr. — Europe, Cape of Good Hope, New Zealand,
United States.

Macrosporium, Fries. — Conidiophores subfasciculate,
softish, erect or ascending, subsimple or branched, coloured,
bearing at or near the apex oblong or clavate, muriform,
coloured conidia.

Some are known to be, and others are suspected of
being, conidial forms of ascigerous fungi.

Macrosporium nobile, Vize, Grev. — Conidiophores fas-
ciculate, short, erect, septate, brown, simple ; conidia
subpiriform or irregular, 4-10 septate, muriform, constricted
at the septa, brown, 60-80 x 40 //•.

Macrosporium tomato, Cke., Rav. Amer. Fung. £xs., No.
603. — Spots orbicular, black; hyphae short, robust, flexuous,
septate; conidia clavate, apex slightly narrowed, scarcely
stipitate, parenchymatous, brown, 100-120X20-22 ft.

Macrosporium solani, Ellis and Mart., Amer. Nat., 1892,

HYPHOMYCETACEAE 441

p. 1003. — Conidiophores erect, curved, caespitose, septate,
50-70X3-4*5 p ; conidia brown, obovate-oblong, many-
septate,, muriform below, septate above, apiculus hyaline,
length including apiculus 100-140 X 15-18 p.

Mystrosporium, Corda. — Conidiophores simple or spar-
ingly branched, rather short, rigid, typically brown • conidia
elliptical, oblong, or subglobose, many-septate, muriform,
dark brown, acrogenous, solitary or rarely subsolitary.

Mystrosporium adustum, Massee. — Forming black
patches on bulbs of Iris reticulata ; hyphae forming a
crust, dark brown, 5-8 p thick, certain cells often inflated ;
conidia elliptic-oblong or ovate, ends obtuse, with 5-7
transverse septa, becoming muriform, septa often oblique,
sometimes with transverse septa only, 45-60X20-22 //,,
smooth, dark brown, translucent, terminal or at the tips
of short branches, solitary.

Mystrosporium alliorum. Berk., Sacc., Syll., iv., No. 2592.
—Conidiophores brown, septate, often flexuous ; conidia
terminal or on short lateral branches, elliptic-oblong or
subpiriform, constricted in the middle, becoming multi-
septate and muriform, septa sometimes oblique, epispore
brown, minutely but distinctly warted, 30-45x8-12 /u,.

Described from Berkeley's type, which has been dis-
covered in the Kew Herbarium.

Stilbum, Tode. — Stroma terete; apex capitate, bearing
the conidia on the tips of the component hyphae ; conidia
minute, continuous, at first involved in mucus.

Stilbum nanum, Massee, Kew Bull^ 1898, p. 112, figs.
11-13. — Conidiophore very minute, scarcely 0^5 mm. high,
gregarious, pale yellow ; stem equal, thin ; capitulum

442 PLANT DISEASES

globose or obovate; conidia very numerous, minute,
hyaline, continuous, elliptical, at first involved in mucus,
5X2-5 p.

Necator, Massee. — Sporodochia shieldlike or discoid,
slightly convex, orange-red, erumpent, gelatinous, covered
by a layer of conidia agglutinated together • conidia oblong
or elliptic, continuous, catenulate, chains at length breaking
up, contents orange.

Necator decretus, Massee, Kew Bulletin, 1898, p. 119.—
Sporodochia discoid, loosely gregarious, sessile, erumpent,
i-i'5 mm. diam., sometimes oblong, 2-2*5 X 1*5 mm., white,
then orange-red ; conidia continuous, ellipsoid, catenulate,
14-18x7-8 p.

Fusarium, Link. — Sporodochium pulvinateor subeffused,
often more or less gelatinous when moist ; conidia fusoid
or falcate, typically pluriseptate at maturity, acrogenous
on branched sporophores.

Subg. Fusamen. — Conidia elongated, continuous.

Subg. Septosporium. — Conidia short, continuous.

Fusarium solani, Sacc., Mich., ii. p. 296. — Globose,
irregular, tomentose, whitish ; hyphae branched ; conidia
fusiform-falcate, 3-5-septate, 40-60x7-8 /*, subhyaline.

Fusarium lycopersici, Sacc., Mich., ii. p. 296. — Hyphae
creeping, variously branched, bearing scattered, subsimple
sporophores; conidia falcate, ends acute, 25-30X3*5-4 /*,
hyaline, then orange.

Fusarium heterosporum, Rees, Nat, Act. Cur., ix.
p. 135. — Sporodochium subtremelloid, spreading, deep
red ; conidia at first globose then fusiform, 30-35 long,
3-septate.

HYPHOMYCETACEAE 443

Fusarium pannosum, Massee, Kew Bulletin, 1898, p.
117. — Sporodochia erumpent, 5-10 cm. diam., suborbicular,
often confluent, bright vermilion, fleshy, subgelatinous,
compact ; hyphae creeping, densely interwoven, branched,
sparingly septate, 4-5 /x thick, hyaline ; conidiophores
sparingly branched, branchlets fusoid ; conidia fusoid,
falcate, ends acute, 3-septate, 35-38 x 5 /*.

Fusarium limonis, Briosi, Act. Staz. Chim. Agrar. Roma,
1878. — Sporodochia gregarious, confluent, white; hyphae
spreading, branched, septate ; conidiophores erect or
ascending, oppositely or alternately branched ; conidia
very variable, acrogenous, continuous, or septate at the
middle, or 2-3-septate, oblong or fusiform, slightly curved,
attenuated, slightly constricted at the septa, hyaline, 26-
27X2-4-2-8 /A.

Chaetostroma, Corda. — Sporodochium discoid or pul-
vinate, black, bordered with black, rigid hyphae; conidia
ovoid or subfusiform, rarely subglobose, borne solitary
at the tips of slender conidiophores, rarely in chains.

Chaetostrcma cliviae, Oud., Ct. Rend. A cad. Sc. Pays-
Bas, 1896, p. 226. — Sporodochia innate on large yellow
spots, inordinate, shining black, orbicular, elliptical or
irregular in shape, up to \ mm. long, finally with a central
opening or a longitudinal slit; surrounded by black,
pointed, septate, more or less flexuous hairs about 210X5
p ; conidia cylindrical, ends rounded, continuous, hyaline,
23-28 x 5-7 /*•

ADDENDA

THE following were unfortunately omitted from their
proper place in the book :—

ROSE MILDEW

(Sphaerotheca pannosa, Lev.)

Too frequently the foliage, young shoots, and flower-
buds of cultivated roses become more or less covered with
a delicate white mildew, which soon presents a mealy
appearance, due to the formation of myriads of conidia.
The conidia are scattered by wind, insects, birds, or syring-
ing ; and generally the disease spreads at an alarming rate,
unless prevented, after having once appeared. As a rule
the leaves curl and fall early in the season, while formation
of conidia is still progressing. On the young shoots and
fruit, the more permanent parts, after the crop of conidia
is completed, the mycelium increases in quantity, finally
presenting a dense, velvety appearance, and often with a
dingy yellow tinge. Later in the season winter fruit, under
the form of minute black points, may be found imbedded
in the dense mycelium. The spores of the winter form
of fruit germinate the following spring, and produce the
conidial phase of the disease.

PREVENTIVE MEANS. — Flowers of sulphur mixed with
about one-third of its volume of slaked lime dusted on the

444

ADDENDA 445

foliage prevents the spread of the disease. Spraying with
potassium sulphide solution answers the same end, and is
not so unsightly on the foliage. Diseased shoots and
fruit should be cut off in the autumn before the winter
fruit falls to the ground.

Sphaerotheca pannosa, Lev. — Mycelium forming a white,
pruinose stratum on living leaves, fruit, and young shoots
of wild and cultivated species of Rosa, Diseased leaves
usually curl and fall after producing conidia only. On the
shoots and fruit the mycelium becomes felted and velvety,
and bears later in the season minute blackish perithecia
immersed in its substance ; perithecia subglobose, append-
ages hyaline, short, ascus solitary, subglobose, 8-spored;
spores elliptical, 20-27 x 12-15 /*•

AMERICAN COFFEE DISEASE

(Stilbum flavidum, Cooke.
—PistiUinaflaviday Speg.)

This disease is almost as destructive to the coffee
industry in the New World as Hemileia vastatrix is in
the Old World.

The symptoms of the disease are unmistakable ; circular
whitish blotches occur on the leaves, often in considerable
numbers, and are equally marked on both surfaces. Using
a pocket-lens, very minute fungi resembling a miniature
pin in shape, and of a clear yellow colour, can be seen
grouped on the spots on the upper surface of the leaf. The
berries are also sometimes attacked, being marked with
circular spots. On the young shoots the pale diseased
spots are elongated.

446 PLANT DISEASES

The disease occurs in Costa Rica, Venezuela, Guatemala,
and New Granada.

PREVENTIVE MEANS. — Although by no means a new
disease, no serious attempt appears to have been made
to arrest its progress. Being quite superficial, it is quite
probable that spraying with Bordeaux mixture, or with
ammoniacal solution of carbonate of copper, would prove
effective. All diseased leaves and fruit should be collected
and burned, otherwise spraying is of little avail.

Stilbum flavidum, Cooke, Grev., 1880, p. n. — Forming
circular bleached spots on living leaves, the bleached
patches pass quite through the leaf; sporophores occur
on upper surface of the leaf, gregarious on the patches,
very minute, entirely clear yellow, 1-2 mm. high, stem
very slender, straight, or flexuous, head globose; conidia
elliptical or subglobose, 2-2*5 x I'5~2 /*•

This is considered by Spegazzini to be a Basidiomycete,
and renamed Pistillaria flavida \ however, I have failed to
find basidia, and so prefer to retain the species under
Stilbum.

APPENDIX

PEA AND BEAN MILDEW
(Peronospora viciae, De Bary.)

Cultivated peas, broad beans, and tares are often
seriously infested by this parasite, which forms a dense
pinkish-grey felt on the leaves, more especially on the
under surface. In severe cases the young pods are also
attacked, but even when this is not the case the injury
done to the foliage alone is sufficient to destroy the crop.

A second species, called Peronospora trifoliorum, De
Bary, mentioned on page 78, also attacks the plants
named above, and to the ordinary observer is indis-
tinguishable from P. viciae. Both are amendable to the
same line of treatment.

PREVENTIVE MEANS. — In the case of peas or broad
beans grown in gardens on a small scale, thorough dusting
with a mixture of powdered sulphur and quicklime at
intervals will hold the mildew in check.

Both kinds of fungi mentioned above are common on
various wild plants belonging to the Leguminosae, and
from thence may pass on to cultivated plants.

447

448

PLANT DISEASES

DISEASE OF YOUNG FRUIT-TREES

(^Eutypella pnmastri, Sacc.)

During the past few years young fruit-trees have in
several places suffered severely from the attacks of a

FIG. i. — Eutypella prunastri. i, portion cf stem of a
plum-tree, showing the conidial condition of the fungus
growing in the living bark ; 2, portion of stem showing the
second condition of the fungus on dead bark. Nat. size.

minute and very inconspicuous fungus. Apples, pears,
and plums, more especially the variety called 'Victoria/

APPENDIX 449

have fared worst in this respect; cherries, peaches, and
apricots to a smaller extent. The stem is the part
attacked, and the tree almost invariably dies the second
season after infection, caused by the complete girdling
and destruction of the cambium. The earliest indication
of the disease is the presence of very slightly depressed or
sunken patches of the bark, which are rough with crowded
and very minute brownish points, just visible to the naked
eye. These points correspond to the openings of the first
or conidial form of fruit of the fungus, from which myriads
of exceedingly minute spores escape at maturity; these
spores are carried by wind, insects, etc., and in turn infect
neighbouring trees.

During the second spring after infection the patches
increase in number, the bark becoming more shrunken,
brown, dead, and not easily removed from the wood. A
crop of spores is again produced the second season, after
which the tree usually dies, unless all the patches of disease
happen to be located on one side of the trunk, when the
tree may continue to prolong its existence for another year.

After the tree is quite dead the diseased patches that
previously produced the conidial form of fruit now give
origin to a second and higher form of fruit, which is recog-
nised by the more scattered and larger pustules or fruit
clusters which burst through the bark.

PREVENTIVE MEANS. — Up to the present all cases of
disease observed have occurred where the trees were
growing in clay land, and the too common practice of
planting too deep in the ground also favours the disease.
The circumstances point to the fact that ample aeration
of the soil is very important.

Up to the age of at least ten years the wounds caused
2 F

450 PLANT DISEASES

by pruning branches or shoots from the stem should be
at once coated with tar. To guard against infection from
spores floating in the air, the stem should be coated with
a mixture of soft soap, quicklime, and washing soda.

Diseased plants should be removed and burned without
delay.

The fungus is often very common on blackthorn, wild
plum, and bullace, and from thence may pass on to young
fruit-trees, hence a sharp look-out should be kept for such
diseased plants in hedgerows, etc.

Massee, Gard. Chron., Sept. 27, 1902, fig. 80. Journ.
Board Agric., ix. p. 361, pi. vi. (1902).

VIOLET DISEASE

(Phyllosticta violae, Desm.)

Cultivated violets, especially when forced too much,
often suffer from this fungus, which has proved very diffi-
cult to check when once established. At first rounded
bleached spots appear on the leaves; these gradually
increase in size and often run into each other, forming
irregular blotches, which show equally on both surfaces
of the leaf. At a later stage very minute black dots
appear on the dead bleached spots. These black points
are the fruit of the fungus, which consist of hollow recep-
tacles containing numerous colourless cylindrical spores
which ooze through a minute opening at the top of the
receptacle in the form of a minute tendril.

PREVENTIVE MEANS. — Spraying with potassium sulphide
will prevent the rapid spread of the fungus, if commenced
at the first sign of the disease, which is in most instances

APPENDIX 451

traceable to the plants being kept in active growth
throughout the year, and consequently being much
weakened and rendered very susceptible to the disease.
A period of rest in a cold frame results in sturdy, disease-
resisting plants.

CARNATION RUST

(Uromyces caryophyllinus, Schroeter.)

A fungus which now and again does a considerable
amount of damage to carnations, as it spreads with great

FIG. 2. — Carnation rust, i, on carnation leaf; nat. size;
2, teleutospores, x 400; 3, uredospores, x 400.

452 PLANT DISEASES

rapidity when once established. Uredo- and teleuto-
spores are frequently to be found growing together in
small pustules forming irregular patches on both surfaces
of the leaves. The pustules or heaps of spores are at
first covered by the white epidermis of the leaf, which
eventually ruptures, exposing the dark-brown masses of
spores. Unlike the Pink rust (Pucdnia arenariae^ Wint),
the Uromyces is not a native of Britain, and has probably
been introduced along with carnations, and in like manner
is transferred from one place to another in this country;
hence it is important to examine carefully all newly-
received carnations.

PREVENTIVE MEANS. — The same as those recommended
under Pink rust, p. 253.

AMERICAN GOOSEBERRY MILDEW

(Sphaerotheca mors-uvae. Berk, and Curt.)

This gooseberry disease, described at p. 97, has quite
recently appeared in a very destructive form in Ireland,
where it appears to be extending its area.

STRAWBERRY MILDEW

(Sphaerotheca castagnei, Lev.)

This destructive parasite, well known as ' hop mildew,'
under which name it is described at p. 95, has recently
completely overrun strawberry gardens in different parts
of the country. The foliage is attacked first, but the
delicate white bloom is not so evident on the leaves as
when it passes on to the fruit, which when ripe is often

APPENDIX 453

completely covered with a white minutely velvety layer of
the conidial form of the fungus. When this occurs the
fruit is practically useless, being unsightly and also insipid,
owing to the greater part of the sugar having been ex-
tracted by the fungus.

PREVENTIVE MEANS. — Great attention is necessary in
order to successfully combat the disease. Wherever the
fungus is known to exist, or where it was present during
the previous season, the foliage should be thoroughly
dusted with flowers of sulphur and quicklime, taking care
to cover the under surface of the leaves, commencing when
the leaves first expand, and repeating at intervals of eight
days. By this means the disease is arrested before it
passes on to the young fruit.

The ascigerous form of fruit, which enables the fungus
to first start growth in the spring, is rarely if ever produced
on the strawberry fruit, but only on the leaves, hence
where the disease has previously existed, it would be
advisable to burn the diseased foliage as described on
p. 108. By this means not only are the resting spores on
the leaves destroyed, but also those that have fallen to
the ground.

POTATO BLACK-SCAB

(Oedomyces leproides, Trabut.)

This fungus, which is described on p. 225 as attacking
beetroot in Algeria and France, has recently been observed
in various parts of England, causing the formation of a
similar disease on potatoes ; a blackish irregularly nodulose
scab is produced which often spreads until the entire sur-
face of the tuber is covered.

454 PLANT DISEASES

Massee, Journ. Board Agric., ix. p. 307, pi. i. (1902).
Potter, under the name of Chrysophlyctis endobiotica,
ibid., p. 320, pi. iv.

FAIRY RINGS

(Marasmius oreades, Fries.)

Fairy rings, in spite of their associations, do a certain
amount of injury to the grass amongst which they grow,
and their presence on lawns is decidedly objectionable.
The fungus named above, which is the one most frequently
forming fairy rings in this country, may be collected and
eaten, being perfectly safe, and of good flavour. This
method of collecting does not, however, destroy the under-
ground spawn or mycelium, which migrates outwards, and
next season will form a fairy ring just outside the ring of
the previous season.

Various other kinds of fungi in addition to the Mar-
asmius also form rings at times, but all are equally amend-
able to the following mode of treatment.

PREVENTIVE MEANS. — Soak the ground thoroughly with
full strength Bordeaux mixture, four times at intervals of
eight days ; or soak with a solution of sulphate of iron in
water, at the rate of one pound of sulphate of iron to a
gallon ; of water, for later applications use the solution half
the above strength. Success depends on the solution
being brought into contact with every part of the infected
area, and also well beyond the zone where the toadstools
are growing. Loosening the turf with a fork enables the
liquid to penetrate more freely.

M'Alpine, Bull. Dept. Agric. Victoria, May 1898.

APPENDIX 455

OAK CANKER

(Stereum quercinum. Potter.)

Professor Potter has described a disease of the oak
caused by a fungus — Stereum querrinum — which proved to
be new to science. The destruction arises from the local
destruction of the cambium year by year, by which the
formation of bast and wood is prevented. The parasite is
dormant during the summer and becomes active during
the winter season, hence the fungus annually destroys the
attempt on the part of the tree to form a callus, and even-
tually an open wound is formed which never heals. The
Stereum appears to be a wound parasite, an entrance
being first effected around the insertion of a dead branch.
Its action on the wood is specially noticeable in the brown
discolouration of the medullary rays. The appearance of
'partridge wood,' so characteristic of the action of Stereum
frustulositm, is not produced by S. querdnum.

Potter, Trans. Engl. Arbor. Soc., p. i, figs. 1-4 (1901-
1902).

CUCUMBER AND MELON LEAF-BLOTCH

(Cer corpora melonis^ Cke.)

This fungus, although first described so recently as 1896,
and at the time considered as a rarity, constitutes at the
present day the most destructive and widespread of
diseases with which the grower of cucumbers, melons,
and other economic cucurbitaceous plants has to contend.
On the other hand, the disease is purely an artificial
creation, being forced into luxuriant growth in the
cucumber-house, saturated with moisture, and exhibiting

456 PLANT DISEASES

anything between 80° and 90° F., where the 'soft' foliage
with ever-turgid cells forms a very suitable medium, on
which the fungus develops so rapidly and luxuriantly that
the whole of the plants in a house 200 feet long are not
unfrequently completely destroyed within a week of the
first appearance of the pest.

The leaves are attacked first ; minute pale-green spots,
looking almost transparent when held between the eye
and the light, are first observable ; these soon increase in
size and run into each other, at the same time becoming
brown, and the whole leaf dies almost at once. This
destruction of the foliage takes place so rapidly that the
plants are simply killed by the over-activity of the roots.

When the diseased leaves turn brown, myriads of conidia
appear on the surface, each supported on a long, slender
stem. These conidia are quickly carried from diseased to
healthy plants by insects, mites, spraying, etc.

Those conidia that fall to the ground germinate at once,
and form a mycelium which spreads rapidly in the soil,
and eventually produces conidia, which also become dis-
persed and aid in spreading the disease. The mycelium
can live in soil until the following season, when conidia
are again formed, and the infection of a new crop follows.

PREVENTIVE MEANS. — Spraying with dilute Bordeaux
mixture containing an insecticide will check the fungus
and also insect-carriers of the spores. The soil should
also be sprayed.

The soil should be thoroughly disinfected after the crop
is removed.

As much air should be admitted into the houses as
circumstances will permit.

Massee, Leaflet No. 76, Board of Agric. (1902).

APPENDIX 457

POTATO BAOTERIOSIS

(Bacillus solanacearum, E. F. Sm.)

A very distinct and well-marked bacterial disease of
potatoes has recently been observed in the north of Eng-
land and in Scotland, and consequently requires a more
detailed notice than that given at p. 342. The disease
has been recognised for some time in the United States,
where it has been carefully studied by Dr. E. F. Smith.
A marked characteristic of the bacterium causing this
disease is the production of a brown colouring matter in
the tissues attacked, hence the course of the disease can
be clearly followed in the haulm and tubers.

The presence of the parasite is first indicated by the
wilting and shrivelling of the leaves. Soon afterwards
dark brown streaks may be seen in the stem. These dark
streaks gradually extend downwards, and pass along the
underground branches into the tubers. Once in the tuber
the disease shows as an imperfectly formed pale-brown
ring, situated at some little distance from the outside of
the tuber. As the disease progresses the brown ring
becomes broader and darker in colour, until finally only
the skin remains, the entire starchy portion of the tuber
having crumbled to powder, and the myriads of bacteria
it contained set free in the soil, where they live until an
opportunity is offered for infecting a fresh crop.

Tomatoes and egg-plants also suffer severely from this
disease in the United States.

PREVENTIVE MEANS. — The leaves or stem are, as a
rule, first inoculated, the bacteria gradually following the
vascular bundles of the stem down into the tuber. In
some instances infection of the tubers may occur directly

458

PLANT DISEASES

FIG. 3. — Bacteriosis of potatoes. Potatoes cut across to
show the disease, i, in an early stage ; 2, advanced stage
of disease.

APPENDIX 459

by the bacteria present in the soil. Dr. Smith considers
that the rapid spread of the disease is caused by insects
of various kinds feeding alternately on diseased and healthy
plants. To prevent such an epidemic, when the disease
is known to be present, the crop should be thoroughly
sprayed with an insecticide, or better, with Bordeaux
mixture containing an insecticide, such a wash being pro-
tective against both insects and Phytophthora infestans.

Diseased tubers should be gathered and burned, not
buried, nor thrown on the manure heap.

When the disease is present and shows a tendency to
spread, the crop should be lifted at the earliest oppor-
tunity, as by so doing many of the tubers may be saved
if allowed to dry thoroughly on the land, and afterwards
used as soon as convenient.

Potatoes showing indications of an internal brown-
coloured ring should not be used for ' sets.'

Smith, Erwin F., U. S. Dept. Agric. Bull., No. 12
(1896).

Massee, G., Journ. Board of Agric., ix. p. 308, pi. xi.
(1902).

INDEX OF PARASITES, FUNGICIDES, AND
BOTANICAL TERMS

ACANTHOSTIGMA PARASITICUM,
114, 369.

Acrospeira mirabilis, 305, 435.
Aecidium, n.

— conorum-picae, 266.
esculentum, 264, 421.

— magelhaenicum, 263, 421.

ornamentale, 264, 421.

pseudo-columnare, 263, 422.

strobilinum, 263, 421.

thomsoni, 267.

Aglaospora taleola, 112.
Algae, 29.
Alternaria, no.

Ammoniacal solution of copper car-
bonate, preparation of, 36.
Anbury, 334.

Anthracnose of scar let -runner, 288.
Armillaria mellea, 14, 201, 386.

mucida, 204, 387.

Arsenic, 40.
Arthrogenous, 31.
Aschersonia, 102.
Ascochyta pisi, 275, 426.
Ascospora beyerinckii, 294, 362.
Asterula beyerinckii, 362.
Aureobasidium vitis, 170.

BACILLI, 30.
Bacillus oleae, 341.

solan acearum, 342.

Bacteria, 30.

Bacterium hyacinthi, 339.
Black blight, 103.
knot, 136.

— rot of grapes, 105.

• rust, 247.

Bladder plums, 85.

Blister-blight of tea plant, 168.

Blood, dried, 53.

Bordeaux mixture, preparation of,

32.
Botrytis cinerea, 148.

douglassii, 160.

galanthina, 159.

paeoniae, 157.

parasitica, 158.

Brachysporium pisi, 315, 437.
Bremia lactucae, 74, 354.
Brown rot of fruit, 300.
Brunissure, 338.
Bulgaria polymorpha, 162, 384.

CAEOMA LARICIS, 238.

pinitorquum, 235, 236.

Calospora vanillae, 113, 368.
Canker, apple-tree, 127.
Capnodium citricolum, 103, 364.

mangiferum, 103.

Carbolic acid, 73.
Cephaleurus minus, 345.

parasiticus, 344.

mycoidea, 343.

— virescens, 343.

Cercospora circumscissa, 317, 438.
gossypina, 290.

resedae, 319, 438.

violae, 319, 438.

— viticola, 319, 439.
Cercospora apii, 316, 438.
Chaetostroma cliviae, 333, 433.
Cherry leaf scorch, no.
Chrysomyxa abietis, 263, 420.

rhododendri, 262, 420.

Chytridium brassicae, 53.
Cladosporium, no.

461

462

PLANT DISEASES

Cladosporium carpophilum, 310,
436..

citn, 310, 436.

elegans, 311, 313, 436.

epiphyllum, 306, 436.

fulvura, 311, 435.

Claviceps purpurea, 122, 372.

Club-root, 334.

Cluster-cup, n.

Cocci, 30.

Coleosporium senecionis, 261, 419.

Colletotrichum althaeae, 290, 429.

gossypii, 290, 430.

lindemuthianum, 288, 429.

spinaceae, 291, 429.

Condy's fluid, 38.

Conidia, 8.

Coral spot disease, 131.

Corticium comedens, 172, 397.

Coryneum beyerinckii, 294, 431.

gummiparum, 122.

Cronartium asclepiadeum, 235, 408.

flaccidum, 235, 409.

ribicolum, 233, 408.

Crown rust, 249.

Cylindrosporium chrysanthemi, 292,

430-

padi, 291, 430.

Cystopus candidus, 59, 352.

cubicus, 61.

tragopogonis, 61, 352.

Cytispora, 113.

Cyttaria berteri, 165, 386.

darwinii, 165, 385.

gunnii, 163, 386.

hookeri, 165, 385.

DAEDALEA QUERCINA, 198, 395.
Damping off, 54.
Dasyscypha calycina, 145, 379.
Dematium pullulans, 309.
Dematophora necatrix, 116.
Diaporthe (Chorastate) taleola,

112, 368.

Diatraea saccharalis, 104.
Dimerosporium mangiferum, 103,

363-

Diplocladium, 329.
Disease, spread of, 17.
Doryphora decemlineata, 342.
Drooping disease of Paeony, 157.
Dry rot, 198.

ECONOMIC CONSIDERATIONS, 47.
Ecoulement blanc, 348.
Egg, dessicated white of, 53.
Endogenous, 31.
Endomyces magnusii, 349.
Entomosporium maculatum, 276,
426.

thumeni, 278.

Epichloe typhina, 125, 372.

Ergot, 122.

Eriksson's theory of the grain rusts,

245-

Erysiphe communis, 362.
Exoascus amentorum, 89, 359.

cerasi, 89, 358.

deformans, 83, 358.

pruni, 85, 358.

turgidus, 89, 359.

Exobasidiura lauri, 168, 399.

rhododendri, 167, 398.

vexans, 168, 398.

vitis, 170, 399.

var. album, 170.

var. tuberculatum, 170.

FAIRY-RING OF CARNATION, 319.
False tinder fungus, 188.
Finger-and-toe, 334.
Fistulina hepatica, 198, 395.
Femes annosus, 182, 393.

fomentarius, 185, 392.

fulvus, 197, 393.

hartigii, 197.

igniarius, 187, 393.

— — pinicola, 197, 393.

ribis, 185, 394.

Foot-rot of orange and lemon, 332.

Formalin, 32.

Fumigation with hydrocyanic acid

gas, 43.
Fungi, definition of, 4.

dispersion of spores of, 15.

how they attack plants, 14.

mode of growth of, 5.

reproduction of, 7.

Fungicides, 31.

poisonous properties of, 46.

Fusarium culmorum, 333.

heterosporium, 331, 442.

hordei, 331.

limonis, 332, 443.

lycopersici, 328, 442.

INDEX OF PARASITES, ETC.

463

Fusarium pannosum, 333, 443.

— solani, 333, 442.
Fusicladium dendriticum, 302, 435.
fagopyri, 435.

pirinum, 304, 434.

Fusicoccum abietinum, 275, 425.
Fusisporium lolii, 331.

GLOEOSPORIUM AMPELOPHAGUM,
278, 428.

bicolor, 288.

fructigenum, 281, 428.

musarum, 287, 428.

nervisequum, 284, 427.

— rhododendri, 288, 429.
ribis, 286, 427.

venetum, 286, 428.

Gnomonia erythrostoma, no, 367.
Grain rusts, 243.
Grapholitha pactolina, 130.
Grey blight of tea plant, 295.
Guignardia bidwellii, 105, 365.
Gummosis of Primus japonica, 306.
Gymnosporangium clavariaeforme,

253, 47.

confusum, 257, 418.

juniperinum, 258, 417.

sabinae, 257, 416.

HAINESIA, 113.

Haustoria, 7.

Heart- wood rot, 191, 193.

Helicobasidium mompa, 166, 400.

Helminthosporium gramineum, 315,

437-

inconspicuum, 313.

teres, 315, 436.

turcicum, 313, 437.

Hemileia canthii, 27, 408.

vastatrix, 27, 231, 407.

woodii, 27, 407.

Herpotricha nigra, 113, 369.

Heteroecism, n.

Heterosporium echinulatum, 319,

439-

gracile, 321, 440.

Hirneola auricula-judae, 165, 399.
Honey-dew, 100.

Hot-water treatment, Jensen's, 40.
Hydnum diversidens, 177, 396.

scheidermayeri, 177, 396.

Hydrocyanic acid gas, 43.

Hyphae, 7.

Hypholoma fasciculare, 210, 389.

Hypochnus cucumeris, 171, 398.

solani, 172, 398.

Hypomyces, 133.

Hysterium macrosporum, 141.

nervisequum, 141.

IRON SULPHATE SOLUTION, pre-
paration of, 37.

JAPAN LILY DISEASE, 57.
Jensen's hot-water treatment, 40.
' Jew's ears ' fungus, 165.

KAINIT, 45.

LEAF CURL, 83.

scald, 276.

Leptosphaeria circinans, 345.

pomona, 269.

Leuconostoc lagerheimi, 349.
Libertella ulcerata, 292, 431.
Lichenes, 29, 342.
Loose smut of oats, 210.

wheat, 210.

Lophodermiummacrosporium, 376.

nervisequum, 376.

pinastri, 139, 377.

Lysol, 32, 73.

MACROSPORIUM, no.

nobile, 322, 440.

solani, 323, 440.

— tomato, 324, 440.
Mal-di-gomma, 333.
Marasmius sacchari, 207, 387.

semiustus, 206, 387.

Matrix, 6.

Melampsora betulina, 238.

laricis, 238, 409.

lini, 238, 410.

pinitorqua, 235, 409.

tremulae, 236.

Melanconium pandani, 293, 431.
Meliola camelliae, 101.

penzigii, 101, 363.

Merulius lacrymans, 198, 396.
Metabolism, 31.
Micrococcus tritici, 339.
Microspbaera grossulariae, 95, 360.
Monilia fructigena, 300, 434.

464

PLANT DISEASES

Morel, tree, 163.
Moth-borer, 104.
Mutualism, 29.
Mycelium, 6.

hibernating, 87.

Mycogone, 134.
Mycoidea parasitica, 343.
Mycoplasma, 246.
Mystrosporium abrodens, 326.

adustum, 325, 441.

alliorum, 326, 441.

Myxogastres, 29.

NEGATOR DECRETUS, 327, 442.
Nectria ditissima, 127.

cinnabarina, 131, 373.

• cucurbitula, 130, 373.

goroshankiniana, 132, 374.

ipomeae, 132, 374.

pandani, 293, 374.

— vandae, 132, 374.

New Zealand white root-rot, 115.
Nitrate of soda, 45.
Nitrification of soil, 31.

OEDOCEPHALUM FIMETARIUM,

384-

Oedomyces leproides, 225, 405.
Oidium tuckeri, 92.
Olpidium brassicae, 53, 349.
Oospora abietinum, 298, 433.

— scabies, 299, 433.
Oospores, 10.
Ozonium auricomum, 346.

PARAFFIN, 40.
Parasites, 5.
Partridge wood, 172.
Peridermium cerebrum, 267.

conorum, 266.

cornui, 235, 422.

coruscans, 266, 422.

elatinum, 266, 423.

filamentosum, 264.

giganteum, 267.

• harknessi, 264.

ornamentale, 264.

pini, 261, 264.

strobi, 233.

thomsoni, 267.

Permanganate of potash solution,
preparation of, 38.

Peronospora cubensis, 80, 356.

- effusa, 79. 355-

gangliformis, 74.

hyoscyami, 81, 357.

maydis, 81, 357.

parasitica, 79, 355.

sachtii, 79, 356.

schleideni, 75, 356.

trichotoma, 78, 355.

trifoliorum, 78, 356.

violae, 80, 356.

Pestalozzia guepini, 295, 432.

hartigii, 297, 432.

Peziza, 159.

vesiculosa, 161, 384.

willkommii, 145.

Pholiota adiposa, 207, 389.

aurivella, 208, 388.

destruens, 208, 389.

squarrosa, 208, 388.

Phoma abietina, 275.

betae, 109.

hennebergii, 272, 425.

sanguinolenta, 270, 424.

solani, 272.

tabifica, 109.

tuberculata, 271.

Phragmidium rubi-idaei, 258, 418,

subcorticatum, 260, 419.

Phycomycetes, 53.
Phyllactinia suffulta, 98, 361.
Phyllosticta apii, 270.

prunicola, 268, 424.

Phylloxera, 69.

Phytophthora cactorum, 66, 353.

infestans, 62, 353.

omnivora, 66, 68, 353.

phaseoli, 65, 353.

Pistillaria flavida, 445.
Plasmodiophora brassicae, 334.

californica, 338.

vitis, 338.

Plasmodium, 30.
Plasmopara viticola, 8, 69, 354.
Ploeospora gummipara, 122, 371.
Plowrightia morbosa, 136, 375.

ribesia, 139, 376.

Pocket plums, 85.
Podosphaera oxyacantha, 98.
Polyporus betulinus, 189, 392.

borealis, 197, 392.

dryadeus, 197, 391.

INDEX OF PARASITES, ETC.

465

Polyporus giganteus, 198, 390.

hispidus, 191, 391.

schweinitzii, 196, 390.

squamosus, 197, 390.

sulphureus, 193, 391.

Poly stigma rubruni, 135, 375.
Poria laevigata, 198.

vaporaria, 180.

Potassium sulphide solution, pre-
paration of, 37.
Powdery mildew of vine, 92.
Pruning, 23.

Pseudomonas campestris, 340.
Pseudopeziza trifolii, 144, 378.
Ptychogaster aurantiacus, 194.
Puccinia arenariae, 253, 416.

— asparagi, 239, 410.

bullata, 250, 415.

coronata, 249, 412

— dispersa, 249, 413.

— glumarum, 249, 413.

— graminis, n, 247, 412.

hieracii, 241, 411.

malvaceafum, 252, 416.

menthae, 230, 411.

phlei-pratensis, 249, 414.

pringsheimana, 243, 411.

pruni, 251, 415.

rubigo-vera, 249.

— simplex, 250, 414.

— tanaceti, 242, 250, 415.
Pythium de baryanum, 54, 350.
intermedium, 56, 350.

QUICKLIME, 39.

RAMULARIA TULASNEI, 107.
' Red stripe ' in wood, 200.
Reed-mace fungus, 125.
Resin wash, 39, 42.
Resting-spores, 10.
Rhizina inflata, 162, 385.

undulata, 162.

Rhizoctinia violacea, 345.
Rhizomorphs, 203.
Rhizopus necans, 57, 351.

nigricans, 59, 351.

Rhytisma acerinum, 142, 377.

punctatum, 143, 378.

salicinum, 144, 378.

Root-rot of conifers, 182.
New Zealand, 115.

Root-rot, white, 116.
Rosellinia ligniaria, 122, 370.

necatrix, 116, 370.

quercina, 121, 369.

radiciperda, 115, 370.

Rotation of crops, 26.

SACCHAROMYCES LUDWIGII, 349.
Saprophytes, 4.
Scab, 299.

of apple, 302.

Schizomycetes, 30.

Schizophyllum commune, 207, 388.

Schleimfluss, 348.

Sciara ingenua, 134.

Sclerotia, 13.

Scolytus rugulosus, 348.

Sclerotinia baccarum, 154, 381.

bulborum, 156, 380.

douglassii, 160, 382.

fuckeliana, 148, 379.

galanthina, 159, 382.

libertiana, 150.

megalospora, 155, 381.

oxycocci, 154, 380.

paeoniae, 157, 383.

parasitica, 158, 383.

sclerotiorum, 150, 381.

trifoliorum, 155, 382.

tuberosa, 157, 382.

urnula, 153, 380.

vaccinii, 153.

Secondary spores, 13.
Septogloeum hartigianum, 297, 432.
Septoria petroselini, var. apii, 270,

426.

Shade trees, 27.
Shot-borer, 104.
Shot-hole fungus, Australian, 268.

317.

Sleeping disease of tomato, 328.
Slime-flux, 348.

fungi, 29.

Soil, nitrification of, 31.

to sterilise, 44.

Sorosporium scabies, 225, 405.

Spermogonia, n.

Sphaerella fragrariae, 107, 366.

tabifica, 109, 367.

Sphaerotheca castagnei, 95, 361

mors-uvae, 97, 362.

pannosa, 361, 444.

2 G

466

PLANT DISEASES

Spirilla, 30.
Sporocarp, 6.
Spraying apparatus, 52.

methods of, 51.

Squirt berry, 271.

Stereum frustulosum, 172, 397.

— hirsutum, 174, 397.
Sterilising soil, 44.
Stigmatea mespili, 278.
Stilbum flavidum, 445.

— nanum, 326, 441.
Stinking smut of wheat, 218.
Sulphur, 38.

flowers of, 94.

Summer fruit, 8.

TAPHRINA AUREA, 91, 360.

— bullata, 90, 359.

— johansonii, 92, 359.

— sadebeckii, 91, 359.
ulmi, 92, 359.

Thread blight of tea plant, 326.
Tilletia caries, 218.

decipiens, 220, 404.

foetens, 220.

levis, 220, 403.

secalis, 220.

— tritici, 218, 403.
Tinder fungus, 185.
Trametes pini, 179, 394.

radiciperda, 182.

suaveoleus, 180, 395.

Trap-crop, 26.

Trichosphaeria parasitica, 114.
sacchari, 103, 365.

UNCINULA SPIRALIS, 92, 360.
Uredo cannae, 368, 423.

Uredo vialae, 268.

vitis, 268, 423.

Urocystis cepulae, 223, 404.
colchici, 227, 404.

— occulta, 221, 404.
Uromyces appendiculaius, 230, 406.

— betae, 228, 407.

colchici, 226, 406.

fabae, 228, 407.

Urophlyctis leproides, 225.
Ustilago avenae, 210, 401.

cruenta, 216, 402.

emodensis, 216, 402.

esculenta, 217, 403.

hordei, 214, 401.

mays zeae, 213, 402.

nuda, 215, 401.

reiliana, 216, 402.

sacchari, 217, 403.

sorghi, 216, 402.

— treubii, -216.
tritici, 213, 401.

• var. folicola, 213, 401.

VERMICULARIA CIRCINANS, 273,

425-
Verticillium, 134.

WHITE ROOT-ROT, 116.

rust of crucifers, 59.

Winter fruit, 10.
Witches' brooms, 89.
Wound-parasites, 15.

XYLEBORUS PERFORANS, 104.
ZOOSPORES, 64.

INDEX OF HOST-PLANTS

ABIES, 182.

excelsa, 113, 263, 298.

douglassii, 298.

— nordmannia, 298.

— pectinata, 114, 163, 263.

pinsapo, 266, 298.

Acacia dealbata, 28.

eburnea, 264.

gummosis of, 122.

horrida, 264.

Acer, 66.

campestre, 142, 143.

platanoides, 142.

— pseudoplatanus, 142, 143.

— rubrum, 142.

— spicatum, 143.
Agrostis canina, 125.
pumila, 221.

— vulgaris, 221.
Albizzta stipitata, 28.
Alder, 89, 91, 127, 193.
Alkanet, 249.
Allium cepa, 224.

magicum, 224.

— rotundum, 224.
Almond, 83, 135, 251, 317.
Alphitonia, 296.
Anchusa arvensis, 249.

officinalis, 249.

Andromeda, 168.
Anemone nemorosa, 157.

sclerotinia, 157.

Anona, 343.
Antholyza, 321.

Apple, 115, 177, 191, 193, 276, 268,
300.

rot, 281.

scab, 302.

tree canker, 127.

Apricot, 251, 268, 317.

Arctostaphylos, 168.
Arrhenatherum, 168.
Asclepia speciosa, 235.
Ash, 127.
Asparagus rust, 239, 345.

BALSAMINA, 161.
Banana anthracnose, 287.

disease, 206.

Barley, 214, 247, 249, 313.

red mould of, 331.

Beans, 116.

Beech, 116, 127, 162, 178, 204, 208.

seedling mildew, 66.

Beetroot, 79, 116, 319, 345.

rot, 109.

tumour, 225.

Beet rust, 228.
Berberis, 247, 263.

vulgaris, u.

Beta vulgaris, 319.

Betula, 182.

Birch, 178, 189, 198.

polyporus, 189.

silver, 89.

Bird-cherry, 87, 127.
Black currant, 233, 286.
Blackthorn, 87.
Broad bean rust, 228.
Bromus, 168, 250.
Bullace, 87.

CABBAGE, 61, 79, 115, 334.

black rot of, 340.

seedling disease, 53.

Cacao disease, 132.

pod disease, 68.

Cactus, 66.
Calathea, 344.
Camellia, 296, 343.

467

468

PLANT DISEASES

Canna disease, 368.
Canthium campanulatum, 27.
Capsella bursa-pastoris, 59.
Carex, 243.
Carnation, 253.

fairy ring, 319.

macrosporium, 322.

Carrot disease, 270, 345.
Cassandra, 168.
Castanea vesca, 163.
Celery leaf blight, 316.

leaf spot, 270.

Cercis, 275.

Chenopodium, 79.

Cherry tree, 89, 136, 268, 276, 300,

3i7-

leaf blight, 291.

mildew, 98.

rust, 250.

spot, 294.

Chestnut disease, 305.
Chrysanthemum, 151.
leaf blight, 292.

— rust, 241.
Cineraria, 242.
Cinnamomum, 343.
Citrus, 296, 343.

bigaradia, 311.

Clarkia, 66.

Clivia leaf blotch, 333.

nobilis, 333.

Clover, 144, 172.

leaf spot, 144.

sclerotinia, 155.

Cocoes, 78.
Coffea, 343.
Coffee disease, 27.

American, 444.

leaf disease, 231.

twig disease, 327.

Colchicum autumnale, 224, 227.

bavaricum, 227.

smut, 224, 227.

speciosum, 227.

Colocasia disease, 78.

esculenta, 78.

Comandra pallida, 235.

umbellata, 235.

Conifer root-rot, 182.

seedling disease, 297.

Coronilla, 78.

Cotton anthracnose, 290.

Cotton root-rot, 346.
Cowberry sclerotinia, 153.
Crataegus, 278.
Cress, 61, 79.
Cucumber, 151.

mildew, 80.

plant disease, 171.

Cucumis sativa, 80.
Cucurbita pepo, 80.
Currant, black, 139.

red, 131, 139.

leaf spot, 286.

Cynanchum vincetoxicum, 235.

DAHLIA, 242.
Dalbergia assamica, 28.
Diospyros, 99.
Dock, 115.
Dogwood, 127.
Douglass pine blight, 160.

EDDOES, 78.
Egg-plant, 272.

bacterial disease, 342.

rot, 132.

Elder, 165.

Elm, 92, 178, 186.

Equisetum, 54.

FAGOPYRUM, 66.
Fagus, 182.

antarctica, 165.

betuloides, 165.

cunninghamii, 163.

obliqua, 165.

sylvatica, 66, 185,

Fenu-grec, 155.
Fern, 115.

Fig-tree disease, 292.
Filbert leaf mildew, 98.
Flax rust, 238.
Fraxinus, 66.
Freesia recurva, 321.
French beans, 288.

GOAT'S-BEARD, 61.
Gooseberry, 139, 286.

American, mildew, 97.

leaf cluster-cups, 243.

mildew, 95.

polyporus, 185.

Grape disease, 271.

INDEX OF HOST-PLANTS

469

Grape fleck, 170.

mildew, 69.

rot, 278.

Grapes, 282, 288.
black rot of, 105.

HARICOT BEANS, 151.

bean rust, 230.

Hawkweed, 242.
Hawthorn cluster-cups, 253.
Hazel, 127, 172.

— leaf mildew, 98.
Heartsease, 80.
Helianthus annuus, 250.
Hemerocallis, 321.
Hemp, 151.
Hieracium, 242.
Holcus, 331.

lanatus, 126.

mollis, 126.

Hollyhock anthracnose, 290.

rust, 252.

Hop mildew, 95.
Hornbeam, 127, 197.
Horse-chestnut, 131.

radish, 61.

Hyacinth, 156, 161. •

bacteriosis, 339.

Hyoscyamus niger, ST.

INDIAN CORN, 81.
Ipomaea batatas, 132.
Iris, 321.

bulb scab, 325.

— — reticulata, 325.

JUNIPERUS COMMUNIS, 113, 182,
254, 257, 258.

nanus, 113, 258.

oxycedrus, 257.

phoenica, 257.

virginiana, 257.

KERGUELEN'S LAND CABBAGE, 61.

LARCH, 193, 196.

canker, 145.

leaf rust, 238.

Larix europaea, 163.
Laurus canariensis, 168.

nobilis, 168.

Ledum, 168.

Lemon, foot-rot of, 332.

scab, 310.

tree, 103.

Lettuce mildew, 74.
Lilium auratum, 57.

candidum, 161.

cpeciosum, 57.

Lily disease, 161.
Lima bean mildew, 65.
Lime, 39.

tree, 127, 131.

Linum catharticum, 239.

usitatissimum, 238.

Lolium, 331.
Lotus, 78.

Lucerne, 144, 155, 343.
Lupin, 172.
Lupinus, 78.
Lycopodium, 54.

MAGNOLIA, 296.
Mahonia, 247.
Maize, 81.

blight, 313.

mildew, 81.

smut, 213.

Mango black-blight, 103.
Mangold, 79.

rot, 109.

Maple, 116, 127.

blight, 297.

Medicago, 78.

lupulina, 155.

sativa, 144, 155, 345.

Medlar cluster-cups, 257.
Melilotus, 78.
Melon mildew, 80.
Mignonette disease, 319.
Mint rust, 230.
Molinia, 331.

Mountain ash cluster-cups, 258.
Mulberry tree, 165, 207.

root-disease, 166.

Muscari comosum, 224.

— racemosum, 224.
Mushroom disease, 133.
Myrtle tree, Tasmanian, 163.

NECTARINE, 317.
Nicotiana glauca, 81.
Niphobolus, 296.
Norway spruce, 263.

470

PLANT DISEASES

OAK, 116, 162, 172, 178, 193, 197,
198, 285, 348.

canker, 112.

seedling disease, 121.

Oats, 247.

loose smut of, 210.

Olive tuberculosis, 341.
Onion mildew, 75.

scab, 273.

sclerotinia, 156.

smut, 223.

Onions, 326.
Onobrychis saliva, 155.
Orange, foot-rot of, 3.

scab, 310.

sooty mould of, 100.

PAEONY, DROOPING DISEASE OF, 1 57.

Pandanus disease, 293, 344.

Panicum, 331.

Paris quadrifolia, 224.

Paspalum, 331.

Pea seedling blight, 315.

spot, 275.

Peach, 83, 115, 251, 276, 282, 317.

rosette, 347.

Pear, 115, 193, 268, 276, 282.

leaf blister, 90. —

cluster-cups, 257. —

scab, 304. ^

Peridermium orientale, 267.
Petunia, 151.
Phaseolus lunatus, 65.

vulgaris, 275.

Phleum pratense, 249.
Picea, 182.

morunda, 267.

sitkaensis, 163.

Pine, 116.

blister-blight, 235.

branch twist, 235.

cone fungus, 263.

cluster-cups, 261.

leaf-cast, 139.

— fungus, 113.
Pink rust, 253.
Pinks, 319.
Pinus, 182.

contorta, 264.

densiflora, 267.

excelsa, 267.

insignis, 262, 264..

Pinus lambertiana, 233.

longifolia, 267.

maritima, 262.

ponderosa, 264, 267.

sabiniana, 264.

siivestris, 262.

strobus, 163, 233, 262.

— • thunbergii, 267.
Pisum sativum, 275, 315.
Plane leaf scorch, 284.
Platanus occidentalis, 284.

• orientalis, 284.

racernosa, 285.

Plum, 85, 136, 197, 208, 268, 300.

leaf blight, 291.

blister, 135.

rust, 257.

scab, 310.

Polygonum chinense, 217.
Poplar, 91, 92, 193, 197, 208.
Populus nigra, 238.

tremula, 236, 238.

Potato, 115, 116, 157, 172, 345.

bacterial disease, 342.

disease, 62.

leaf curl, 323.

rot, 333.

scab, 225.

American, 299.

— sweet, 59.

Pringlea antiscorbutica, 61.
Prothallia, damping-off, 56.
Prunus americana, 137.

chicasa, 136.

japonica, gummosis of, 306.

maritima, 137.

pensylvanica, 137.

serotina, 137.

virginiana, 137.

Pseudotsuga douglassii, 160.
Purging flax, 239.

QUASSIA, 343.
Quercus nigra, 235.

tinctoria, 235.

Quince, 90, 276.

RADISH, 61, 79, 334.
Rape, 79.
Raspberry, 210.

rust, 258.

spot, 286.

INDEX OF HOST-PLANTS

471

Red currant, 131, 139, 286.
Rhododendron, 296.

— ferrugineum, 167.

— galls, 167.

— hirsutum, 167, 262.

— rust, 262.
Ribes alpinum, 233.

— aureurn , 233.
— nigrum, 233.

Robinia, 66, 193.
Rose mildew, 444.

rust, 260.

Rye, 122, 247, 249.

grass, 331.

smut, 221.

SAFFRON, 345.
Sainfoin, 155.
Salsify, 61.
Sambucus nigra, 165.
Saxifraga, 168.
Sau tree, 28.
Scarlet-runner, 230, 288.

anthracnose, 288.

Scilla bifolia, 224.
Scorzonera, 61.
Scots fir, 130, 196.
Screw pine disease, 293.
Sedge, 243.
Sempervivum, 66.
Senecio jacobea, 262.

vulgaris, 262.

Sequoia gigantea, 160.
Shepherd's-purse, 59.
Sidalcea, 161.
Silver birch, 89.

fir, 130, 141, 197, 208, 266, 297.

girdling of, 275.

leaf disease, 1 14.

Sloe, 135.

Snowdrop mildew, 159.

Solanum dulcamara, 62.

melongena, 132.

tuberosum, 62.

Sorghum halapense, 216.

saccharatum, 216.

vulgare, 216.

Sorrel, 115.
Spinach, 79.

• anthracnose, 291.

Spruce, 116, 130, 197, 297.
Strawberry leaf blight, 107.

Sugar-cane agaric, 207.
— brand, 217.

disease, 103.

Sunflower rust, 250.
Swedes, 151.
Sycamore, 131.

leaf blotch, 142.

Symplocus, 168.

TANACETUM, 251.

Tanias, 78.

Tanniers, 78.

Tayas, 78.

Tea plant, blister blight of, 168.

• grey blight of, 295.

thread blight of, 326.

Timothy grass, 249.
Tobacco mildew, 81.
Tomato, bacterial disease of, 342.

bacteriosis, 338.

black rot, 324.

leaf rust, 311.

sleeping disease, 328.

Trifolium, 78, 144.

— incarnatum, 155.
Trigonella fenu-graecum, 155.
Trisetum, 250.

Triticum, 250.
Tsuga mertensiana, 163.
Tulip mould, 158.
Turnips, 151, 334.

ULMUS CAMPESTRIS, 186.
Unonis, 78.

VACCINIUM, 99, 168.

— myrtillum, 154.

oxycoccos, 154.

uliginosum, 155.

vitis-idaea, 153.

Vanda tricolor, 132.

— suavis, 132.
Vangueria infausta, 27.

— latifolia, 27.
Vanilla disease, 113.

planifolia, 113.

Vicia, 275.

Vine, 116, 170, 319.

leaf rust, 268.

powdery mildew of, 92.

sclerotinia, 148.

Viola odorata, 319.

472

PLANT DISEASES

Viola tricolor, 80.

Violet, 319.

Neapolitan, 80.

WALL-FLOWER, 61, 79, 334.
Wellingtonia, 160.
Weymouth pine, 196.

rust, 233.

Wheat, 220, 221, 247, 249, 326.
— bacteriosis, 339.

— disease, 272.

Wheat, loose smut of, 213.

red mould of, 333.

stinking smut of, 218.

Whitethorn, 115, 135.
Willow, 180, 193.

ZEA MAYS, 216, 313.
Zinnia, 151.
Zizania latifolia, 217.
Zizyphus jujuba, 345.

INDEX TO THE APPENDIX

AMERICAN GOOSEBERRY MILDEW,
452.

BACILLUS SOLANACEARUM, 457.
Bean and pea mildew, 447.

CARNATION RUST, 451.
Cercospora melonis, 455.
Cucumber leaf-blotch, 455.

EUTYPELLA PRUNASTRI, 448.

FAIRY RINGS, 454.

Fruit-trees, disease of young, 448.

GOOSEBERRY, AMERICAN, MILDEW

OF, 452.
Grass, 454.

MARASMIUS OREADES, 454.

Melon leaf-blotch, 455.

OAK CANKER, 455.
Oedomyces leproides, 453.

PEA AND BEAN MILDEW, 447.
Peronospora trifoliorum, 447.

viciae, 447.

Phyllosticta violae, 450.
Potato bacteriosis, 457.
black-scab, 453.

SPHAEROTHECA CASTAGNEI, 452.

mors-uvae, 452.

Stereum quercinum, 455.
Strawberry mildew, 452.

UROMYCES CARYOPHYLLINUS, 451.
VIOLET DISEASE, 450.

Edinburgh : Printed by T. and A. CONSTABLE.

UNIVERSITY OF CALIFORNIA
NCH OF THE COLLEGE OF AGRICULTURE

THIS BOOK IS DUE ON THE LAST DATE
STAMPED BELOW

Mas s ee

3B731

A text-b

of plant

diseases

1907

LIBRARY, BRANCH OF THE COLLE-GE OF AGRICULTURE