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MEMOIRS

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TORREY BOTANICAL CEDE

VOLUME IX

A MONOGRAPH

OF

THE ERYSIPHACEAE

BY

BERNESTI S. SALMON, ELS

NEW YORK

1900

A MONOGRAPH

THE ERYSIPHACEAF

ERNEST S. SALMON, F.L.S.

IssuED OCTOBER 4, 1900.

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INTRODUCTION

The Zrysiphaceae are popularly known in different countries as
“White” or “Powdery Mildews," “ Blight,” Mehlthau, Blanc,
Honungs-dagg, etc. Throughout the summer they are con-
spicuous in their “ Oidium,” or conidial stage on many common
plants, e. g., roses, hops, vines, peas, maples, P/antago, Heracleum,
Pol Spiraea, Corylus, Quercus, Crataegus, etc., and give to
the infected parts of the host-plant a whitish mealy or dusty ap-
pearance due partly to the white web-like mycelium, and partly to
the presence of myriads of rapidly-formed white conidia.

Later in the summer, and in autumn, the ascigerous form of
fruit is produced in the shape of small, more or less globular,
dark brown or black perithecia, usually provided with special out-
growths termed appendages. After producing these the mycelium
often dies away, and the perithecia are left as small, blackish,
globular bodies on the surface of the leaves and stems of the host-
plant. Sometimes, however, the mycelium is thick and persistent,
and the perithecia are then found more or less immersed in it.

The Zrysiphaceae are characterized by the truly parasitic habit,
the white mycelium, the production of large, colorless (or white)
non-septate conidia on simple, erect conidiophores (forming the
Oidium stage), and the indehiscent perithecia, or cleistocarps
(mostly provided with appendages of a very definite form), con-
taining non-septate ascospores. The family thus limited contains
the genera Podosphaera, Sphaerotheca, sonra; Microsphaera,
Erysiphe, and Phyllactinia.

Memoirs Torrey Botanical Club, Volume IX. :

(1)

2 A MONOGRAPH OF THE ERYSIPHACEAE

The limitation of the Family Zrysiphaceae to these six genera
is not in universal use. Saccardo in the * Sylloge " (307)* divides
the family into two sections: Amerosporae, with the characters
* sporidiis ovoideis continuis hyalinis" contains the above six
genera; the other, Dictyosporae, “ sporidiis clathrato-septatis"" in-
cludes the single genus Saccardia. Saccardo has, however, in a
later work (313) excluded Saccardia from the family. Karsten
(196) creates the sub-family “ Zrysipheae Karst.” to include as
well the genera Capnodium, Perisporium, Anixia, and Eurotium.
Schroeter (319) includes in the family Apiosporium and Lasio-
botrys, and Jaczewski (176) Eurotium, Apiosporium, Dimerosporium,
and Microthyrium.

The muriform spores of Saccardia seem sufficient to place this
genus outside the Erysiphaceae; Apiosporium, Dimerosporium,
Lasiobotrys, and Capnodium differ in the black mycelium, etc.;
Eurotium and Anixia are saprophytic; Perisporium has septate
spores, and Microthyrium is far removed in the scutiform, not
cleistocarpous perithecia. All these genera, also differ in not
possessing the “ Oidium” form of conidia.

The Erysiphaceae belong to the Order Perisporiales of the
Class Ascomycetes. In the same order is the Family Perispori-
aceae, to which the Zrysiphaceae show nearest relationship.
The closed perithecium, or cleistothecium, as it is sometimes
termed, of the present family, must be considered as showing
a low degree of development, and places the Zrysiphaceae
(together with the Perisporiaceae) among the simplest forms of
the Ascomycetes. The characteristic feature of the Zrysiphaceae
is their true parasitism: the small size of the perithecia, and
the abundant formation of conidia, capable of quickly infecting
new hosts, must perhaps be considered rather as being adapta-
tions to this mode of life than as primitive characters. Too much
significance must not be attached to the presence of appendages
to the perithecia. These appendages are strictly homologous to
the mycelial outgrowths from the external cells at the base of the
perithecium which occur in many genera of the Ascomycetes. In
the Family Ascobolaceae of the Order Pezizales these outgrowths
(called collectively the “secondary mycelium” by Woronin) re-

* The numbers refer to the Bibliography given at the end of the volume,—ED.

MORPHOLOGY AND LIFE-HISTORY 3

call at once the appendages of some species of iow (see
Woronin, Beitr. Morph. Phys. Pilz 2: 3, pl 2. f. 7,8). We
must remember, too, that in Ærysiphe and Sphaer ue the appen-
dages are often obsolete. The function of this “secondary my-
celium ” is, generally, to secure the attachment of the perithecium
to the substratum ; in the Zrysiphaceae the outgrowths have ap-
parently been specially modified for purposes of distribution.

Harper (161) has some interesting remarks on the subject of
the relationship of the ExyszpAaceae.

MORPHOLOGY AND LIFE-HISTORY.

The ordinary vegetative mycelium consists of very numerous,
delicate, white or colorless septate hyphae, frequently branched and
more or less densely interwoven. The septa divide the hyphae into
rather long cells, which according to Harper (161) contain, as a
rule, only one nucleus, although cases where two to four nuclei occur
are not uncommon. In all the genera except Phyllactinia, the hy-
phae of the vegetative mycelium produce haustoria at intervals
which pierce the cuticle and swell out into a bladder-like form in the
epidermal cells. These haustoria serve both to attach the fungus to
its host and to draw nourishment from it. The haustorium is
very narrow at the point where it pierces the cell-wall, and is fre-
quently, at its entrance into the interior of the epidermal cell, sur-
rounded by a sheath-like process proceeding from the cell-wall
(see Fig. 155). According to Harper (161) each haustorium con-
tains a single nucleus, situated towards the end, or in the middle
of the bladder-like swelling or sac. This sac applies itself closely
to the nucleus of the epidermal cell, and at length is completely
surrounded by this nucleus, which gradually becomes disorgan-
ized, forming a thick granular coat round the haustorium. Finally,
the whole of the protoplasmic content of the host cell becomes
disorganized. The haustoria originate from the mycelium in three
different ways ; they may spring direct from the under surface of
a hypha at a point where it is closely applied to the surface of the
host plant, and at once pierce the cuticle. These are termed austoria
exappendiculata,; or at certain places, at the side of the hypha,
flattened semicircular processes appear, usually small, not exceed-
ng: in width the diameter of the hypha, and from the under sur-

4 A MONOGRAPH OF THE ERYSIPHACEAE

face of these (which are closely appressed to the cuticle), or from
the hypha itself at the point where the swelling originates, the
haustoria are produced in the usual manner—these are termed
haustoria appendiculata ; or, finally, the hyphae are sometimes
provided with processes, often on both sides at the same point,
which are more or less deeply lobed or crenulate at the margin,
or reniform in shape, and from these swellings, or from the hypha
itself adjacent to them, the haustorium proceeds—these are haus-
toria lobulata (Fig. 128).

The genus Phyllactinia shows some important differences in
the manner of producing haustoria. As pointed out by Palla
(264), in his valuable paper, the vegetative mycelium on the under
surface of the host-leaf does not send haustoria into the epidermal
cells, but forms special hyphal branches, of limited growth, which
enter the stomata, penetrate into the intercellular spaces, and finally
send haustoria into the surrounding cells of the spongy-paren-
chyma (Fig. 163). Each of these special branches, or “ Ernäh-
rungshyphe," consists of two, three, or rarely more cells, and is
sometimes sufficiently long to extend through the spongy-paren-
chyma to the palisade-ceils, but no haustorium has been observed
to be formed in the cells of this layer. Each * Ernährungshyphe,”
of which sometimes two pass through the same stoma, produces a
single haustorium, in all cases, from its last cell. Sometimes two
haustoria (produced by different hyphae) are found in one cell.
The haustorium itself does not differ from that found in the other
genera of the Erysiphaceae.

With the exception of the haustoria, and the special branches
of Phyllactinia, the mycelium of the Erysiphaceae is entirely super-
ficial, z. e., external to the tissues of the host-plant. In the rose
mildew, Sphaerotheca pannosa, it has been frequently stated that
the mycelium hibernates during the winter months within the tis-
sues of the host-plant, but this statement appears to rest merely on
supposition.

The first kind of reproductive bodies borne by the mycelium
are the asexually-produced conidia, which are formed under favor-
able circumstances, throughout the summer and during the early
part of autumn. The mycelium produces special hyphal branches,
the conidiophores, which are erect, simple, colorless or white, thin-

MORPHOLOGY AND Lirke-HisrORY 5

walled, one-to-many septate, about 10% thick, and from 110 to
380 high. From these the conidia are formed by abstriction,
either singly at the apex or in long chains in basipetal succes-
sion. The conidia are continuous, 7. e., non-septate, colorless or
white, oblong, cylindrical, or barrel-shaped, smooth, thin-walled,
and from 20-50 x 10-24 in size. Harper (161, p. 664) states
that a single nucleus passes from the parent-hypha into the young
conidiophore, and that from it arise the nuclei of all the conidia
subsequently formed.

Conidial forms of the Erysiphaceae were formerly classified as an
autonomous genus of the Hyphomycetes under the name of Oidium.
It soon became observed, however, that the Oidium was frequently
succeeded by species of the Erysiphaceae, or that the Oidium
even occurred among the perithecia of the latter. Berkeley in 1841
(26, see also 29) was among the first to give conclusive evidence
ofthe organic connection of the Oidium with the Erysiphaceae.
It is now well known that during the stage in which the conidial
form is just passing over into the perithecial, conidiophores and
perithecia may frequently be observed in organic connection.

The conidia are usually formed in immense numbers through-
out the summer, and being easily carried by the wind, are the means
of rapidly spreading the fungus during the growing season. It
may be noted that Wagner (380) observed in several instances the
distribution of conidia effected by snails, and mentions that the
conidia of Erysiphe polygoni on plants of Hypericum by this means
were carried to plants of Aquilegia, and those of Sphaerotheca
Castagnei on Impatiens to other plants (see also Stevens (340*) ).

The conidia are capable of immediate germination on reaching
the epidermis of a suitable host-plant. Even in a dry atmosphere,
but more readily in a damp one, or in water, one or more delicate
germinal tubes are produced near one end of the conidium. Soon
the first haustorium is formed (sometimes immediately on ger-
mination), and from this center hyphae grow out, branching,
crossing, and developing haustoria. ` The vegetative mycelium
thus formed continues to develop, and under favorable conditions
begins to produce conidia in a few days.*

Cen, E
* Dangeard (96) has observed cases of conidiophores being produced direct from
the germinating conidium.

6 A MONOGRAPH OF THE ERYSIPHACEAE

The second phase in the life-history of the Evysiphaceae occurs
later in the summer, or in autumn, usually when the vitality of the
host-plant begins to diminish. The formation of conidia is then
gradually superseded by that of perithecia, containing ascospores,
or resting-spores, whose function is to carry the fungus in a dor-
mant condition through the winter, when host-plants are not
available.

The history of the development of the perithecium was first
investigated by de Bary (98 and 99). At the crossing point of
two hyphae, or at the place where two neighboring hyphae touch,
each develops a small upright branch, which is soon cut off by a
septum from the parent hypha. One of these branches swells to
an oval-oblong shape, and becomes the oögonium. The other
lengthens slightly, and applies itself closely to the side of the
oögonium, curving above so that its end lies on the apex. The
uppermost part is then cut off by a septum, and forms the anthe-
ridium.

De Bary observed no breaking down of the wall between the
antheridium and the oögonium, and so supposed that no conju-
gation took place, but nevertheless considered that these organs
represented a true sexual apparatus, and that the perithecium sub-
sequently formed was to be regarded as the result of a sexual act.
This last conclusion has lately been strikingly verified by the
work of Harper. The following details are taken from the two
important papers of this author (160 and 161).

The oögonium and antheridium each contain a single nucleus,
At the time of fertilization the cell-wall between the two organs is
dissolved, and the nucleus of the antheridium enters the oogonium,
„and unites with its nucleus. At this point the protoplasm of the
antheridium is in direct contact with that of the oogonium ; soon,
however, after the passing over of the nucleus of the antheridium
into the oögonium, a fresh wall is formed between the two organs,
and then only a small quantity of protoplasm is found in the an-
theridium. At the time when the union of the two nuclei takes
place, the development of the walls of the future perithecium
begins. From the stalk cell of the oögonium a number of hyphal
branches spring, closely pressed side by side, and grow upwards,
forming a single layer round the oogonium. The stalk cell of the

: MORPHOLOGY AND LIFE-HISTORY T

oögonium then swells to a circular shape, and a second series of
hyphae, internal to the first, grow up in a similar manner. The
hyphae of both series branch and intertwine, completely growing
together, and forming finally a pseudo-parenchymatous tissue. A
number of branches grow from the internal layers of this primary
coat towards the interior of the developing perithecium and, re-
peatedly branching, fill up all interstices. The cells of these
branches, which are very rich in protoplasm and contain several
nuclei, disappear in the course of the growth of the perithecium,
becoming absorbed by the developing ascus or asci. The cells of
the outer layers become greatly flattened, and lose their protoplas-
mic contents, the external ones becoming dark brown and forming
the outermost wall of the perithecium.

The odgonium after fertilization is known as the carpogonium,
and undergoes certain changes, which vary slightly according as
one or several asci are formed.

In Sphaerotheca, where a single ascus is found, the following
growth takes place. At about the time when the two primary
layers of hyphae have grown up from the stalk-cell, the carpo-
gonium begins to elongate, and nuclear division takes place, result-
ing in the formation of a single, more or less curved row of five
or six cells. In the penultimate cell of this row,two large nuclei
are always present, while the other cells contain only one each.
This penultimate cell is the young ascus. It swells strongly, so
that the apical cell of the series is pushed aside and downwards,
and finally absorbed.. The two nuclei now fuse, and the ascus
rapidly increases in size, pressing together and flattening the cells
of the inner layers of the young perithecium. The nucleus in-
creases in size, and finally divides three times, providing the nuclei
for the eight ascospores which are subsequently produced by free-
cell formation. In Ærysiphe, where several asci are produced in
the perithecium, the development is, with slight modifications, the
same as that of Sphaerotheca (see Harper (161)).

The fusion of the nuclei in the young ascus is evidently to be
regarded as a vegetative one, similar to that which occurs in
basidia, cystidia, and the asci of the other fungi—even some-
times, according to Massee (240), in the hairs of some of the
Discomycetes. Dangeard (96) however, regards the fusion of

8 A MONOGRAPH OF THE ERYSIPHACEAE

nuclei in the young ascus as of sexual significance, and denies the
primary sexual fusion of the nuclei of the .oógonium and anther-
idium ; but, as Wagner (379*) points out, the weight of evidence
is against accepting Dangeard's theory.

When the perithecia are about half-grown, certain cells of
the outer wall, situated either apically, equatorially, or basally
begin to grow out into the appendages. These appendages, if
basal, may be floccose and more or less similar to the hyphae of
the mycelium, with which, as in the genus Zrysiphe, they are fre-
quently interwoven ; usually, however, they are quite distinct from
the myselium, erect or radiating, and sharply characterized in
shape. In Phyllactinia they are acicular and bulbous at the base
' (figs. 170, 171); in Uncinula hooked at the apex (see Plates
4 and 5), and in Podosphaera and Microsphaera they are variously
branched in a dichotomous manner (see Plates 1 and 2).

It is difficult to say definitely what part the appendages play in
the life-history of the Zrysiphaceae, although it is generally sup-
posed that they are concerned with the distribution of the peri-
thecia (see Gardner, 142).

The perithecium of Phyllactinia, besides the acicular append-
ages, possesses a basal mass of special branched hyphae, which
certainly serve in the first place to attach the perithecium to the
leaf, and in some cases, perhaps many, causes it subsequently to
adhere to foreign substances.

The asci contained in the perithecia are colorless sacs, stalked
or sessile, globose to cylindrical in shape, and from one to 66 (or
more) in number. They contain from two (or abnormally only
one) to eight spores. The wall of the ascus is from 1-5 p thick,
and usually becomes very thin at the apex of the ascus. No true
paraphyses are present, although this name has been given by
some authors to the isolated portions of the inner wall, often of a
filiform shape which sometimes occurs in the perithecia (especially
in Phyllactinia).

The ascopores are colorless, continuous (7. e., non-septate),
granular, oval, oblong, or occasionally roundish, with obtuse ends,
rarely slightly curved, 15-34 (rarely reaching 50) x 8-25 pin size.

The perithecia are truly cleistocarpous, the asci being liberated
by the irregular rupture of the wall. This takes place in the

MORPHOLOGY AND LIFE-HISTORY 9

spring following the season in which the perithecia were produced.
In some cases, as in Erysiphe galeopsidis, and, as a rule, in Æ.
graminis, the ascospores are not formed until the following spring,
the protoplasm of the asci remaining throughout the winter in a
granular condition. It appears that the ascospores are incapable
of immediate germination, and require to pass through a resting
stage, lasting the winter months. Galloway (139) and also
Worthington G. Smith (329) state that in the spring the perithe-
cia, under favorable conditions, suddenly burst and forcibly eject
the asci. Harper (161, p. 663) mentions that the cells of the inner
wall of the perithecium permanently retain their nuclei and proto-
plasmic contents, and suggests that they may produce a substance
capable of swelling in water, and so causing the rupture of the
perithecium. :

The ascospores in a damp atmosphere or in water send out in
a few hours germ tubes, which (according to Wolff ) on reaching
the epidermis of a suitable host-plant penetrate and form a haus-
torium, from which center the ordinary vegetative mycelium is
produced. Very.little, however, is known on the subject, and no
records exist, apparently, of any artificial infection of host-plants
by means of ascospores. Galloway (139) has made some valuable
observations on the ripening and germination of the ascospores in
Uncinula necator and Wolff (398, 399) in the case of Erysiphe
graminis, and Tulasne has recorded cases of the commencement
of germination of the ascospores of Phyllactinia corylea, Sphae-
rotheca pannosa'and Erysiphe tortilis.

With the formation of perithecia the mycelium frequently en-
tirely disappears. Sometimes, however, as in Sphaerotheca pannosa
and Erysiphe graminis, it is persistent, and produces special
branches in the form of long, branched, interlaced, shining, thick-
walled hyphae, in which the perithecia are more or less immersed.
It has been stated that in certain species, viz, Sphaerotheca pannosa,
Podosphaera oxyacanthae, P. leucotricha and Uncinula necator, the
mycelium is perennial, passing the winter months in a state of hi-
bernation; definite proof of. this, however, has not been given in
any case.

It is sometimes found that perithecia, which externally present
the normal appearance, instead of containing asci, emit when opened

10 A MONOGRAPH OF THE ERYSIPHACEAE

a stream of very small, biguttulate spores, 6.5-10.5 x 3. 5-64
in size, immersed in a colorless mucilaginous substance. In such
cases there may usually be found on the same mycelium paler and
smaller bodies, globular, oval, or pyriform in shape, without appen-
dages, and containing the same kind of spores. Similar bodies
are frequently formed in the joints of the conidiophores when they
usually bear at their apex the shrivelled remains of the chain of
conidia.

Prior to De Bary’s searching investigations into this subject in
1870 (99), these bodies were known as pycnidia, and the con-
tained spores as stylospores, and by the older botanists were thought
to be another form of reproduction of the Evysiphaceae. De Bary,
however, showed that the pycnidia and spores belonged to a minute
fungus living parasitically within the hyphae of species of the Zry-
siphaceae. The vegetative mycelium of this parasitic fungus (Am-
pelomyces quisqualis) is composed of a great number of closely
septate hyphae, which run singly inside the hyphae of the host.
The fruit of the Ampelomyces is produced either in the perithecia,
conidiophores, or cells of the host mycelium. If the species
attacked is in the perithecial stage, the parasite forms its fruit in
the interior of the perithecium, absorbing the asci and sometimes
sending its hyphae into the appendages. The variation in shape
of the pycnidia is due to the difference in the maturity of the peri-
thecia attacked. If the host is in the conidial condition, the fruit
of the Ampelomyces is produced in the transformed cells of the
conidiophores, and in this case the presence of the parasite seems
to prevent any subsequent formation of perithecia.

De Bary succeeded in infecting germinating conidia of species
of the Zrysiphaceae with the spores of A mpelomyces, and found
that the latter on germination at once penetrated the germinal
hyphae of the conidia.. In some cases, the spores of the Ampelo-
myces germinated after they had been kept for three months in a
dried condition. They are, therefore, probably capable of infect-
ing fresh hosts after passing through the winter in a resting state.
Ampelomyces has been observed on most of the species of the
Erysiphaceae, and no doubt plays an important part in checking
their spread, by lessening their vitality, and often preventing the
formation of perithecia (see Griffiths, 1 53, pp. 184, 185).

HISTORICAL 11

In the Erysiphaceae, as in other groups of parasitic fungi, we
find that in some years, from unknown causes, the species attack
certain host plants in a marked manner. This is well illustrated
by the wave of disease, caused by Sphaerotheca humuli, which
periodically sweeps over the cultivated hop, and in the attacks,
by the same fungus, in certain years on cultivated strawberries ;
and it is not the less noticeable with regard to wild host-plants.
Some interesting biological notes, on this and other points, are
given by Griffiths, in his paper on “ Some Northwestern Zrysipha-
ceae” (152).

The frequency with which great devastation is caused by mem-
bers of the present family to cultivated plants of high economic
value makes the study of their life history a matter of importance.
The two worst diseases are those caused by the vine and hop
mildews (Uncinula necator and Sphaerotheca humuli), which at
certain periods have caused wholesale destruction to the cultivated
vines and hops of the world. Other well-known diseases are
caused by the rose mildew (Sphaerotheca pannosa), the apple
mildew (Podosphaera leucotricha) and the pear and cherry mildew
(P. oxyacanthae), the gooseberry mildew of America (Sphaerotheca
mors-uvae) and the gooseberry mildew of Europe (Microsphaera
grossulariae), the pea, bean and turnip mildew (Erysiphe polygoni),
and the corn mildew (E. graminis).

All these diseases, it is now proved, are able to be held in
check by the prompt use of certain fungicides. I have endeav-
ored to give full instructions for the preparation and use of the
best remedies under each species of mildew causing a disease.

HISTORICAL

Linnaeus in the Species Plantarum (1753) mentioned a fungus
under the name of Mucor Erysiphe—“ Mucor albus, capitulis fus-
cis sessilibus. Habitat in foliis ZZumuli, Aceris, Lamüii, Galeopsidis,
Lithospermi.’ By this name the four species of the Erysiphaceae
now known as Sphaerotheca humuli, Uncinula aceris, Erysiphe
galeopsidis (on Lamium and Galeopsis) and E. cichoracearum were
in all probability intended. In 1767, in the “ Mundus Invisibilis "
(222) Linnaeus spoke of Erysiphe as a genus (giving, however, no
strict definition). Persoon, in I 796 (Obs. Myc. 1: 13), gave the

12 A MONOGRAPH OF THE ERYSIPHACEAE

name Sclerotium Erysiphe to Linnaeus’ species, and in 1801 (Syn.
Meth. Fung. 1: 124) separated the plant on Corylus as var. f
corylea (= Phyllactinia corylea).

In 1804, in a work by Rebentisch (295) we meet with the first
illustration. The fungus was called Sclerotium suffultum, and
represents the species now known as Phyllactima corylea.

In 1805 De Candolle (62) published the mss. genus “ Erysiphe
Hedw. f.,” and very briefly described, often under several different
names depending on the host-plant, the species now known as
Phyllactinia corylea, Uncinula salicis, Erysiphe polygoni, E. cicho-
racearum, and Microsphaera berberidis. De Candolle in 1806, in
the Syn. Pl. Gall. added Arysiphe aceris (= Uneinula aceris) ; in
1807 (64) E. oxyacanthae (= Podosphaera oxyacanthae), and in
1815, in vol. 6 of the Flore Francaise the species now called Micro-
sphaera euonymi, M. astragali, M. alni var. lonicerae, Sphaerotheca
humuli, Uncinula prunastri, Erysiphe graminis and E. galeopsidis.

In 1815, also, Bivoni Bernardi (41) described and figured Ery-
siphe vagans (= Phyllactinia corylea) and E. clandestina (= Unci-
nula clandestina). The figures of both are good, and in that of the
latter species the uncinate apex of the appendages is carefully shown.

In the same year Fries in Obs. Myc. p. 206, united all the
hitherto described species under the name of Erysiphe varium.

The alteration of the spelling of the genus to “ Erysibe” orig-
inated with Nees von Esenbeck, in 1817 (257), who used the
name “ Erysibe suffultum Rebent.” for the Erysiphe suffultum of
that author, and subsequent authors followed in attributing the
word “ Erysibe" to Rebentisch.

In 1819 the most important of the early works on the Zry-
siphaceae appeared. These were Wallroth’s two papers, one en-
titled “ Naturgeschichte des Mucor Erysiphe,” in the Berlin Gesell.
Nat. Freunde Verband 1: 6-45; the other, called “ De Mucore
Erysiphe Linnaei observationes," in the Annal. Wett. Gesell. 4:
226—247. UT

Through Wallroth's work an important addition was made to
the existing knowledge of the family. It may be said that in all
works prior to this date the host-plant on which the Erysiphe grew
afforded the chief specific character. Wallroth pointed out that
the same species often grew on a great number of different host-

HISTORICAL 13

plants and insisted on the need of each species being defined by
morphological characters. Attention was also directed to the
value of the appendages as affording diagnostic characters, and the
various shapes and mode of branching shown by these organs
were carefully noted.

With respect to nomenclature, Wallroth made some unfortu-
nate changes. Regarding the name Zrysiphe as unsuitable (on ac-
count of its derivation from the Greek word ’spvaißn, which is
stated to have meant rodigo, or rust), Wallroth proposed A/phito-
morpha in its place, and used the name Erysibe to supersede the
genera Uredo, Ustilago, etc. These changes, however, were not
adopted by subsequent authors, and it need only be mentioned that
in accordance with the laws of botanical nomenclature, Wallroth's
reasons for overthrowing the name Zrysiphe for the present group
are insufficient.

An appendix by Schlechtendal immediately followed Wall-
roth's paper in the Berlin Verhandl. This work is especially in-
teresting from the fact that it is here for the first time clearly rec-
ognized that the Zrysiphaceae may be divided into two groups, one
in which the perithecia contain a single ascus with eight spores,
the other in which these contain severalasci. This important fun-
damental difference is well shown in a figure.

From 1819 until 1851 little advance was made.

In 1823 Kunze (208) founded the genus Podosphaera for the
“ Sphaeria myrtillina” of Schubert, and gave good figures illus-
trating the characters of the genus.

Link, in 1824, in Willdenow's “ Species Plantarum," arranged
the species described up to that time in two sections, " sporangi-
olo unico," and “ sporangiolis pluribus."

In 1825-27 Greville, in the Scottish Cryptogamic Flora, de-
scribed and figured Erysiphe pisi (= E. polygoni), E. adunca (=
Uncinula salicis), and Eurotium rosarum (= Sphaerotheca pannosa).

Perhaps the most important works about this time were Fries’
Syst. Myc. (1829), Duby’s Botanicon Gallicum (1830), and Wall-
roth’s Fl. Crypt. Germ. (1833), although they added but little to
the existing knowledge of the Erysiphaceae.

In 1834 Schweinitz (322) published an account of the North
American forms, in which sixteen new species were described ;

14 A MONOGRAPH OF THE ERYSIPHACEAE

‘many of these, however, were the same species on different host
plants.

In 1838 Corda (92) figured Erysiphe Perisporium (= E. poly-
goni) and E bicornis (= Uncinula aceris).

During 1846-9, Durieu and Montagne (109) described several
species from Algeria.

In 1851 Léveillé published in the Ann. Sci. Nat., his classical
monograph entitled ‘‘ Organisation et Disposition méthodique des
espéces qui composent le genre Érysiphé." In this work after
dividing the Erysiphaceae into two sections, “‘ Sporangium unicum ”
and “Sporangia plurima," Léveillé arranged the species in five
genera, viz, Podosphaera Kze. and Sphaerotheca Lev. belonging to
the first section, and Phyllactinia Lev., Uncinula Lév., Calocladia
Lév. (afterwards changed to Jzrosphaera (see L c., 381) and
Erystphe Hedw. f. DC. (emend.) belonging to the second.

These genera, based on characters shown by the appendages,
are still found to embrace all the known species of the Zrysipha-
ceae. For establishing these extremely natural genera, and for
the broad view shown in the treatment of species, Léveillé’s work
has long been recognized as of the highest value.

In 1861 the brothers Tulasne described fully and illustrated
sixteen species of the Erysiphaceae in the first volume of the Selecta
Fungorum Carpologia. The five plates, engraved on copper, con-
tain the most beautiful illustrations of the family existing, and
show well the stages in the life-history of both the conidial and
perithecial form. The genera established by Léveillé are not
kept up, the species all being referred back to the old genus
Erysiphe.

In 1870 De Bary’s great work on Zrysiphe in the “ Beiträge
zur Morphologie und Physiologie der Pilze" appeared. Here the
general life history of the Erysiphaceae, and especially the history
of the development of the perithecia, were minutely investigated.
In a systematic appendix De Bary divided the family into two
genera—Podosphaera, with the characters “ carpogonia orthotropa.
Ascus in quoque perithecio unicus (rarissime, lusu, 2), octosporus ;
and Erysiphe, “ carpogonium campylotropum. Asci in quoque
perithecio 4 aut plures.”

In 1872 Cooke and Peck published their papers (90 and 91) on

CONNECTION BETWEEN Host AND PARASITE 15

the Erysiphaceae of the United States, describing a number of new
species.

Karsten (1873) in Myc. Fenn. (192) and, later (1885) in the
Act. Soc. Faun. Fl. Fenn. (196) described the Zrysiphaceae of
Finland, and in 1884 Winter monographed those of Germany in
Rabenhorst’s Krypt. Fl. Deutschl. (394).

In 1887 the important work entitled the “ Parasitic Fungi of
Illinois, Part 2, Erysipheae” by Burrill and Earle appeared. It
would be difficult to praise this work too highly for the clear de-
scriptions of the species (28 in number), the careful enumeration
of the host-plants, and especially for the broad view shown in the
conception of what constitutes a natural species. Burrill’s excel-
lent account of the North American species in Ellis and Ever-
hart’s N. Amer. Pyrenomycetes (1892) is based on the above
work, and contains some important additions.

In 1893 Schroeter enumerated the Zrysiphaceae in Cohn’s
Krypt. Fl. von Schlesien, in 1896, Jaczewski published his “Mon-
ographie des Erysiphées de la Suisse” (176), and in 1897 Oude-
mans described the species found in the Netherlands (263).

In 1895 Harper’s valuable work (160) on the history of the
development of the perithecium appeared.

At the beginning of 1899 Palla published his important paper
“Ueber die Gattung Phylactinia.” It is here pointed out that
Phyllactinia differs from the other genera in producing its haus-
toria from hyphae sent through the stomata of the host-leaf. As
a result of this interesting discovery, the Zrysiphaceae are now
divided into two sub-families, the Erysipheae and the Phyllactineae.

In Saccardo’s “Sylloge Fungorum” (1882-1899) an enu-
meration of all the published species of the Erysiphaceae is given.
Meschinelli (248), in his work on fossil Fungi, describes and fig-
ures a genus Zrysiphites, with one species (= Erysiphe protogaca
Schmalh.) found on Ficus kiewiensis in one of the Tertiary forma-
tions in Russia.

GENERAL REMARKS ON THE CONNECTION BETWEEN Host
AND PARASITE
In the Zrysiphaccae, perhaps as much as in any group ot
fungi there has been, especially in the past, an undue multi-

16 A MONOGRAPH OF THE ERYSIPHACEAE

plication of species. For example, more than twenty forms
of Phyllactinia corylea (notwithstanding that this is the most
sharply characterized species in the family) have been published
as new species. For the most part, these “species” were sup-
posed to be confined to the host-plant on which they were discov-
ered, and after which they were named ; this was the case with
Erysiphe fraxini, E. betulae, E. alni, E. mali, E. fagi, E. quer-
cus, E. pyri, E. ilicis, E. cerasi, etc.

It is interesting to note that even among the earlier authors
this unscientific practice of making a new species of a form be-
cause it occurred on a new host-plant did not pass unreproved. -
As early as 1819 Wallroth (383, p. 18) says: “Es ist ein ganz
irriger Glaube und ein unverzeihlicher Fehler der F lüchtigkeit, wenn
wir * * * so viel Arten der Epiphyten aufgestellt und nach den
Pflanzen selbst, auf denen sie hervorbrechen, benennt finden als
deren selbst sind.” Again, in 1851, when Léveillé arranged in
clearly defined species the great mass of named forms (often dis-
tinguished merely by the host on which they grew) which had
accumulated since Wallroth’s time, the same warning is repeated ;
“Pour les reconnaitre on deyra les étudier seulement quand ils
auront atteint leur plus haut degré d’organisation et ne plus faire
attention aux végetaux sur lesquels on les rencontre. Cette
maniere de les denommer est essentiellement vicieuse, elle conduit
a la confusion et ä l’erreur.”

In Saccardo’s * Sylloge" 111 species, and 1 variety, and 20
species “ dubiae vel inquirendae," are enumerated, To this num-
ber must be added 8 species and 6 varieties, either accidentally
omitted from the Sylloge, or published subsequently.

In the treatment of the family in the present paper 49 species
and II varieties are recognized. Of these three species and two
varieties are new to science.

This great reduction of species will not be wholly unexpected,
as a similar process has been found necessary in the treatment of
the family by several authors, in works published subsequently to
the * Sylloge." Winter, for instance, in his work on the Erysi-
Phaceae of Germany, reduced several of the European species enu-
merated in the “ Sylloge," and in 1887 Burrill and Earle (61) sim-
ilarly accounted for many of the American species of Schweinitz,

CONNECTION BETWEEN Host AND PARASITE 17

as well as for several of those described by later American
authors.

The further reduction of species that has been made in the
present work may be ascribed mainly to two causes: (1) The ne-
cessity of adopting a wide view of a species when dealing with
material from all parts of the world; and (2) The adoption of the
principle that classification must be based primarily on morpholog-
ical characters.

As a necessary consequence of adherence to the latter view,
the connection of a’parasitic fungus with a certain host-plant can-
not be considered as affording a character of specific importance.
If it were to be proved that two forms of a fungus, morpholog- .
ically indistinguishable from one another, occurring on different
species of host plants, were incapable of infecting any but their
respective hosts, then these two forms might be classified as
* biological " varieties or species, and in such a case the connec-
tion between the parasite and its host would become a character
of systematic importance. No such evidence, however, is at
present adduced in connection with the members of the Zrysi-
phaceae. For the present, therefore, to mention one example,
such a species as Sphaerotheca epilobii, supposed to be confined
to species of Zpilobium, but morphologically indistinguishable
from certain forms of the polymorphic S. kumuli, cannot be main-
tained.

The question of the systematic value of the connection be-
tween host and parasite is one of great importance. The connec-
tion is frequently treated as affording a character of primary spe-
cific importance, and it will, perhaps, not be out of place here to
utter a protest.against this practice. The method of classification
commonly followed in dealing with parasitic fungi is well illus-
trated in the treatment the genus Phoma has received. Over
1,000 species are enumerated in Saccardo's “ Sylloge," and the
majority of these are named after the host-plant on which they oc-
cur. That the connection of parasite and host is here made the
character of primary importance can be seen from the treatment of
the genus given in local floras. Allescher in enumerating 570
species of Phoma, in Rabenhorst's Kryptogamen Flora Deutsch-
lands, has adopted an arrangement thus described : ** Die Arten der

18 A MONOGRAPH OF THE ERYSIPHACEAE

Gattung Phoma, sind im Folgenden je nachdem sie auf Holzge-
wächsen, krautartigen Dicotyledonen, Monocotyledonen, oder
Kryptogamen wachsen, und in jeder Abtheilung nach den alpha-
betisch geordneten Nährpflanzen angeordnet.” When in place of
such an arrangement as this, where the connection between host
and parasite is considered of primary specific importance, and
where a mere alphabetical list is substituted for a natural classifica-
tion, a monograph of the genus Phoma appears in which the species
are defined by morphological characters, a more scientific method
in the classification of fungi will have commenced.

After the forms of the Zrysiphaceae have been grouped around
what may be termed ‘‘ morphological centers," the next most im-
portant work is to experiment biologically with them. Such ex-
perimental work remains, unfortunately, almost entirely to be
done. A few instances are on record of attempts to sow the
spores of one species on the host-plants peculiar to another species,
e. g., the spores of E. graminis on the host-plants of ZE polygoni,
and those of E polygoni on the vine, the host-plant of Uncinula
necator ; in all cases without success.

An experiment performed by Magnus (mentioned in detail under
Sphaerotheca), although unfortunately incomplete, is of great inter-
est. Conidia of Sphaerotheca humuli growing on the hop, were
taken and sown on Taraxacum officinale, a common host-plant of S.
humuli var. fuliginea. This variety (considered a distinct spe-
cies by Burrill and most American authors) is distinguished
by the much larger cells of the perithecium, usually dif:
ferent character of the appendages, etc. The conidia of S.
humuli germinated on the Zaraxacum, and produced a mycelium
bearing conidia. Observations were not continued to see if peri-
thecia would be produced. From this experiment we are led to
one of three conclusions. We must suppose either : (1) That the
conidia of S. kumuli on this host would have produced ultimately
the perithecia at present considered characteristic of the var.
fuliginea, in which case we should have to consider the latter as
merely a form of S. humuli induced by growing on certain host-
plants. This view is rather favored by the fact that in some
species we have certain forms associated with certain hosts which
present slight morphological differences, although these are not

RELATION BETWEEN Host AND PARASITE 19

sufficiently marked to prevent the forms from being considered as
belonging to the species. Or (2) We must suppose that the coni-
dia of S. kumuli on a strange host-plant, although producing a
mycelium capable of giving rise to conidia, might be unable to con-
tinue its development and produce perithecia, in which case the
form would quickly die out. Certain Ordium-forms, e. g., that on
species of Myosotis, appear seldom, if ever, to produce perithecial
fruit. Finally, (3) That the conidia might have ultimately produced
perithecia similar to those of ordinary S. humuh, This seems
perhaps unlikely, when we remember that S. kumuli has never
been recorded on Taraxacum, notwithstanding that this plant is
a common weed in many places (e. g., hop-gardens) where s.
humult grows.

The compilation of a list of the host-plants of the Erysiphaceae
is attended with many difficulties.

1. In the first place the fungus has frequently been wrongly
determined in Exsiccati. An instance will make this clear, and il-
lustrate how wrong plants may become recorded as hosts for certain
species. In eleven examples from certain Exsiccati “ Sphaerotheca
Castagnei" is given as the species occurring on these hosts :—
Inula hirta (Sacc. Myc. Ven. 630), Plantago maritima (Rab.
Fung. Eur. 1916), P. major (Rab. Fung. Eur. 1048), Achillea Ptar-
mica (Rab. Fung. Eur. 1051), Senecio sylvaticus (de Thüm. Fung.
Austr. 441), Eupatorium. cannabinum (Cooke, Fung. Brit. Exsicc.
ed. 2, 591, 592), Trifolium medium (Syd. Myc. March. 3052),
Calystegia sepium (Syd. Myc. March. 43 2), Catalpa syringaefolia
(Syd. Myc. March. 1640), Falcaria vulgaris (Syd. Myc. March.
1541) and Stachys alpina (Sacc. Myc, Ven. 1491). In the first
six specimens the fungus is Exysiphe cichoracearum, in the next
four E. Polygoni and in the’ last Æ. galéopsidis. Here we have
eleven species of host-plants wrongly given for one species in
specimens sent out in exsiccati. It is, moreover, probable that
the error does not stop here, but that it is perpetuated by the
fungus on these hosts being named and recorded as “S. Castag-
nei” without examination by subsequent collectors ; itis significant
that four of the plants given above are stated to be hosts of .S.
Castagnei by several authors.

2. The list of host-plants has been further complicated by the

20 A MONOGRAPH OF THE ERYSIPHACEAE

practice followed by many authors of determining a plant specific-
ally in its conidial (Ozdium) stage. As yet, we do not know enough
about the conidial form (which is possibly as variable in some
species as the perithecial is known to be) to be able to determine
it specifically with safety, and it is certain that the practice of doing
so had led to many errors. I have, therefore, as far as it has been
possible, omitted in my host-index those records in which the
fungus has been observed only in the conidial condition. The
treatment which the fungus on Cucurbitaceae (Cucumis, Cucurbita)
has received, affords evidence of the danger of naming the conidial
forms. In herbaria and published records the fungus is stated
almost without exception, to be Sphacrotheca Castagnei. Schroe-
ter, however, having observed the perithecial stage on Cucurbita
Pepo, has named it Erysiphe polygoni. In collections and exsiccati
this fungus on Cucurbitaceae exists apparently only in the conidial
stage, and the only specimen that I have seen with perithecia
occurred on Cucurbita Pepo, in late autumn, at Reigate, Surrey,
England. On this specimen the fungus is undoubtedly Erysiphe
eichoracearum, the species recorded on Cucurbitaceae by American
mycologists.

3. Certain common species of Erysiphe are, in my experience,
always wrongly determined. . In Europe there is a species, not
uncommon on Valeriana officinalis which, without exception, has
been referred to E. communis. (E. polygont) by authors; it is, how-
ever, undoubtedly Æ. cichoracearum. The fungus not uncommon
on Anchusa officinalis and Echium vulgare has been named E,
eichoracearum, and no records exist of E. polygoni occurring on
these hosts, yet all the specimens I have seen in herbaria are really
to be referred to the latter species. The only fungus on Galium
that I have seen is E cichoracearum, yet it is always named in
European herbaria and exsiccati Æ. communis (E. polygoni), and
is so recorded in all works.

I have thought it advisable, therefore, on account of the con-
fusion that exists in many cases, to compile a host-index from
‚personal observations, chiefly with the view of seeing if any facts
of interest could be gained on the subject of the general relation
between parasite and host. By means of the abundant material
received from many parts of the world, and through the examina-

RELATION BETWEEN Host AND PARASITE 21

tion of the chief herbaria, I have been enabled to observe the oc-
currence of species of the Arysiphaceae on 1002 different species of
host-plants.* To make the list, as far as possible, complete, I have’
incorporated 367 additional host-plants recorded in the literature
of the subject, and have also noted all those cases in which a dif-
ferent species of mildew to that personally observed on any host-
species has been recorded by authors. In both the latter cases
the plants are distinguished in the host-index by an asterisk,
and the.authority for each record is indicated in the list of host-
plants given under the respective species of fungus. The names
of the host-plants have been, so far as possible, brought into ac-
cordance with those of the Index Kewensis.

The restriction of the parasite in its choice of host-plants varies
greatly in the species of the Erysiphaceae. Many species, e. g.,
Erysiphe tortilis on Cornus sanguinea, Uncinula geniculata on Morus
rubra, and Podosphaera biuncinata on Hamamelis Virginiana have
a more or less wide geographic distribution, and yet, so far as at
present known, are absolutely confined to their respective host-
plant. About as many instances occur in which the hosts of the
fungus are limited to one genus; e. g., Uncinula aceris, its var.
Tulasnei, and U. circinata are confined to species of Acer; U.
flexuosa to species of Æsculus, and Sphaerotheca lanestris to species
of Quercus. A few species are limited in their choice of host-
plants to certain families, e. g., Uncinula salicis on Salicaceae,
Sphaerotheca pannosa on Rosaceae, Erysiphe graminis on the
Gramineae. Finally, many species occur on a great number of

* A word may be given here on the right manner of using the host-index. Rightly
used, it affords, when the name of the host-plant is known, a useful clue toward iden-
tifying an unknown species, and in a certain sense serves as a key to all the species of
the Erysiphaceae, wrongly used, it may easily be the means of perpetuating errors. To
illustrate, if there be but one species of fungus recorded on the host-plant in hand, it i

en necessary merely to turn to the description of the fungus and see if the icis
to be named agree in the characters given. The practice of naming a fungus from a
host-index, without examination, cannot be too strongly condemned. If several spe-

host-plant in hand is not to be "es among those of the host-index, it is not to be as-

sumed that this gives any reaso: supposing that the fungus is a new species, as the

host list is necessarily very gieren in such cases the keys to an genera and spe-
ies must be consulted,

92 A MonoGRAPH OF THE ERYSIPHACEAE

host-plants of very different affinities. I have observed Phyllactinia
corylea on hosts belonging to 48 genera, in 27 different families,
and Erysiphe polygoni on 190 different species of host-plants, be-
longing to 89 genera. The latter species has been reported on
146 additional host-plants (some of which, however, must be
considered doubtful).

The members of the Erysiphaceae fall into the following divi-
sions; 15 species and 2 varieties are confined to a single species of
host-plant ; 15 species and 5 varieties to species belongings to one
genus; 4 species and 1 variety to those belonging to one family,
and 15 species and 3 varieties show little or no preference in select-
ing their hosts. In the species of the first division it seems reason-
able to suppose that the connection between host and parasite
must bea very intimate one. In those of the last division it seems
probable that the connection is slight.

The number of cases in which more than one species or va-
riety of mildew has been observed on one species of host-plant is
rather large; on one host-species five different mildews have been
recorded in one case, four in four cases, three in 24 cases, and two in
163 cases. These numbers have been obtained by taking into ac-
count all the published records, and are therefore (especially with
regard to those cases in which two species of mildew have been re- |
corded on the same host) probably far too high. In the present con-
fusion that exists concerning the hosts of many species it is impossi-
ble to give exact numbers ; probably, in the last case mentioned, 100
in the place of 163 would be nearer the mark. In many cases it is
probable that an error in identification has led to different species of
the Erysiphaceae being recorded for one host-plant. For instance,
on Verbascum phlomoides I have seen Erysiphe taurica ; E. cichorace-
arum is recorded by Magnus, and Æ. polygoni by Dom. Saccardo ;
E. cichoracearum grows commonly on Achillea Ptarmica, and it
may perhaps be doubted if the two other species—Z£. taurica and
E. polygoni, recorded on this host, really occur. It is needless to
give further examples, as these can be found in the host-index.
On the one hand it is quite certain that in a large number of cases
more than one species of mildew grows on one host-species ; on
- the other hand, it is equally certain that in many of the recorded
cases of this kind wrong determinations have been made. It is hoped

RELATION BETWEEN Host AND PARASITE 28

that by means of the asterisk prefixed to the plants in the host-
index attention will be directed to this point, and so lead mycol-
ogists to clear up these doubtful records. The work is difficult, as
it consists in many cases in proving that a certain species does not
grow on a certain host-plant; this can only be hoped to be ac-
complished by continued observations for many years, at the end
of which time it might be safe to disregard many published
records.

One curious source of error still remains to be noticed. It
has, up to the present, been generally supposed that it is a safe
practice to consider perithecia found on any host-plant as originat-
ing there. Many cases that have come under consideration prove
that this is not so. In some instances stray perithecia of certain
species occurring on strange hosts have been published as new
species. This is the case with “ Zrysiphella Carestiana,” which
was founded on perithecia of Phyllactinia corylea accidentally
adhering to the pileus of Fomes fomentarius. “ Uncinula Co-
umbiana" is, I believe, merely U. salicis on the leaves of Scu-
tellaria, and “ Erysiphe vitigera" appears to have been established
on stray perithecia of Æ. cichoracearum, occurring on the vine.
Similiar cases, mentioned in detail under the respective species are
the following: Uncinula salicis on Artemisia vulgaris, U. prunastri
on Lonicera Xylosteum, U. Delavayi on Celtis, Phyllactinia corylea
on probably many herbaceous hosts and Microsphaera alnion Pop-
ulus grandidentata. Uncinula geniculata has occurred ‘appar-
ently accidentally on Aydrophyllum appendiculatum. I have
seen, in herbarium specimens, Podosphaera tridactyla adhering
in a tangled mass to a leaf of Fagus sylvatica, and perithecia of
Phyllactinia corylea accidentally present on a rose leaf. A few
perithecia of Microsphaera alni have been seen among those of M.
diffusa on a leaf of Desmodium paniculatum, and, also, in a speci-
men named M. grossulariae, adhering to the margins of goose-
berry leaves.

The accidental presence of perithecia on plants may perhaps
be accounted for in some cases by the rubbing together of dried
specimens in herbaria, or possibly by the repeated use of the same
drying paper to which perithecia would adhere, in pressing the
leaves.

24 A MONOGRAPH OF THE ERYSIPHACEAE

DISTRIBUTION.

The Zrysiphaceae have practically a world-wide distribution.
It can, however, be said that their headquarters are in the North
Temperate Zone, as they occur in the greatest numbers in the Uni-
ted States and parts of Europe. The most southern record is
that of Phyllactinia at the Beagle Channel, Tierra del Fuego, in
the extreme south of South America. One species probably,
Erysiphe cichoracearum, has been recorded from the tropical island
of St. Thomas, off the west coast of Africa; Phyllactinia corylea
occurs in Guatemala, and Sphaerotheca pannosa is reported from
the West Indies. As regards the northern limit, Zrysiphe cichora-
cearum is found in Lapland, and Podosphaera oxyacanthae in Green-
land. i

As examples of species with a very wide range of distribution
may be mentioned Erysiphe polygoni, E. cichoracearum, E. graminis,
Microsphaera alni, Podosphaera oxyacanthae, Uncinula salicis, Sphae-
rotheca humuli, and Phyllactinia corylea.

Arranging the species as they occur on the main areas of land
we have the following table :

ij 0.0 vo.
` of species of vars. endemic species. endemic vars.
Europe, 27 5 9 3
Africa, 7 I PE LE
sia, 25 3 4 I
Australia and
New Zealand, 5 re SC =
America, 31 7 I4 5

We find, therefore, that out of the 49 species and r1 varieties
of the Erysiphaceae, no less than 27 species and 9 varieties are
endemic in the above sense, that is to say, nearly four-sevenths of
the species and 9 out of the 11 varieties.

These 27 “endemic” species and 9 varieties are variously fur-
ther limited in distribution, and it is interesting to note that most of
them are confined either to a single species of host.plant or to
one genus ; e. g., Erysiphe trina is known only from California on
the single species Quercus agrifolia, while E. tortilis has a wide
European range on Cornus sanguinea.

The number of species confined to the Old World is 18, with

DISTRIBUTION 25

4 varieties ; to the New World, 14 species with 5 varieties ; leav-
ing 17 species and 2 varieties common to both.

In dealing with the features of distribution, however, we must
remember that while Europe and the United States. have been
well-worked for the Zrysiphaceae, little has yet been done in in-
vestigating the family in Africa, Asia and Australia.

An interesting fact is the occurrence in Japan of two species,
Uncinula Clintonii and U. polychazta, hitherto supposed to be en-
demic to America. Sphaerotheca mors-uvae, widely spread in the
United States on species of Ribes, appears to be identical with the
European species S. Zozntosa growing on species of Zuphorbia.
Microsphaera euphorbiae is not uncommon in the United States
on Euphorbia and Astragalus, and appears in Asia (Turkestan) on
Colutea and Astragalus (M. coluteae). Uncinula necator, long sup-
posed to be endemic to North America, was discovered in 1892 in
France, and has now been found in species of Actinidia-in Japan.
U. Australiana, on Lagerstroemia ovalifolia in New South Wales,
has been sent by Prof. Miyabe, on Z. /ndica, from Japan.

Most of the species of the Erysiphaceae show a wide range of
variation in their characters, and the description of each species
given in the following pages will usually be found to be much
wider than that hitherto given by authors.

Examination of a large amount of material has shown con-
clusively that such characters as the persistence or evanescence of
the mycelium, the size of the perithecium, the number of asci,
and in many cases the number of spores are far more variable
than is generally supposed. On the other hand, just as we find
that a classification based on differences in the shape of the ap-
pendages divides the family into natural genera, so also we find
that frequently the best specific characters are those derived from
the appendages. The minute differences in the shape, mode of
branching, etc., of the appendages are specifically constant, and
usually show far less variation than other characters. It is im-
portant to note, however, that the mature condition of the ap-
pendages is necessary to show these specific characters ; many
erroneous descriptions have arisen from the examination of only
immature stages.

At the end of the synonomy of each species, a list of exsic-

H

L4

26 A MONOGRAPH OF THE ERYSIPHACEAE

cati is appended. Only those are quoted which have been per-
sonally examined, and unless prefixed by an asterisk, or followed
by information as to the source, all the numbers refer to the copies
in the Kew Herbarium. Those distinguished by an asterisk are
to be found in the Herbarium of the British Museum (Natural
History). It is necessary to state exactly what copies have been
examined, as—in the case of microscopic fungi especially— different
copies of the same numbers in exsiccati may contain different species.

I have not attempted to deal with the described species of
Oidium in the present work, only mentioning those which are
generally admitted to be the conidial stage of known species of
the Erysiphaceae, as, e. g., O. Tuckeri and Uncinula necator, O.
monilioides and Erysiphe graminis, etc. In all probability the
genus Oidium is not autonomous, but consists entirely of conidial
forms of the Erysiphaceae. About 50 species of Oidium have been
published ; of these six are already known to be the conidial stage
of certain species, and over twenty-five of the remaining species
grow on plants known to be the hosts of species of the Erysiphaceae.
I have not included in the descriptions of the species of the Æryst-
phaceae the characters shown in the conidial (Oidium) stage. In
many species, indeed, this stage has not, at present, been observed.
In those cases where only dried material was available, the ex-
amination would not have been satisfactory, as in studying the
Oidium-form living material is necessary in order to arrive at such
characters as the number of conidia produced in the chain, the
size and shape of the ripe conidium. I hope at some future time
to investigate this branch of the subject.

aterial examined has been for a large part found in the rich patas of
Brie in the Royal Herbarium, Kew. This collection includes
ec

SS In this occur, besides Berkeley’s types, no less than 98 specimens sent by
Léveillé to dis author ( Léveillé's herbarium, M. P. Hariot informs me, w
in 1870 during the Franco-Prussian war); also a number of specimens sent by Castagne,
Kidigi óh "ee and a few examples from Schweinitz’ herbarium. For the great facil-
ities afforded me in the use of this collection I am under obligations to the Director of
the Royal Gardens, Kew.

Next in er bes bete the pre collection me sent on loan by Prof.
F. S. Earle. the American rey ee
€ is valuable as being the material used by Professor Burrill and Professor ee
well-known work on the family (61).

ACKNOWLEDGMENTS 21

r other American material I am indebted to Prof. W. Trelease, who kindly sent
for Gras the iine T the Missouri Botanic Gardens; also to Mr. S Ld
Ellis, Prof. G. P. Clin PO Lon. Pammel for the Zrysiphaceae in the ER
of the Iowa emt Fw eng College; and to Pro i
mens, many of great interest from the Herbarium of the United States Department of
Agriculture. These latter are now deposited in the Royal Herbarium, Kew
Mr..David Griffiths kindly sent me a large collection (over 100 specimens) gathered
in South Ee Wyoming and Montana; these also are now placed inthe Royal
Herbarium, Kew.
M. P. Hariot courteously sent me on loan the Erysiphaceae contained in the Paris
Museum. This collection is of great interest, as it includes Montagne’s herbarium,
as examined by Léveillé. In this herbarium are ane 25 specimens of Wall-
Wer: eegen by Léveillé ; see 214, p. I 15); 33 specimens from Léveillé's herba-
rium ; and numerous en from Castagne and other authors
o Prof. W. Tranzschel I am indebted for the loan of a representative collection of
Russian Zrysiphacea es
Prof, Kingo Miyabe sent a large and extremely valuable collection, accompanied
by notes of Japanese specimens. This contained several species not hitherto recorded,
from Asia, and included two | new omg and one new variety. The specimens are de-

the Upsala Museum, Bee: those of Fries’ herbarium; Prof. L. Jost st for the loan
of Duby’s herbarium, and also specimens from a Nees von i Esenbeck; etc., con-
tained in the herbarium of the University of Strassburg ; M. Casimir de Candolle for

cimens from De Candolle's herbarium ; Prof. E. aie for Ott’s herbarium in the

the geg? e the herbarium of the St. Petersburg Botan ic © Garden $ Prof. C
his collection x seien Erysipha

I wish also to thank the Reeg at the British Museum (Natural History) for
= me every opportunity of studying the collection of Erysiphaceae in this erba-

lel ase types, to the following botanists:
C. H.

Pilop: que C. H. Dem "e Prof. A. Macacsy Diete, Prof. P. Gennardius, Prof.
.W. B .W.D.H

: Kelsey
Prof. G. de , Prof. D. McAlpine, Prof, T. H. McBride, Prof. G. Massalongo,
Prof. E. Palla, M. N. Patouillard, Prof. E. poen. Prof. C. H. Peck, Prof, O. Penzig,
Dr. H. Rehm, Prof. E. Rostrup, Prof. A. D. Selby, Prof. A. B. Seymour, Rev. A. C.

I have especially.to thank Prof. P. Magnus, Prof. P. A. Saccardo, Mr. P. Sy-
dow, and Prof. L. M. € not only for several CET specimens, but also for
information given on several poin

To M: rge Massee for e constant advice and kind assistance in many ways,
I wish to express my most sincere thanks.

24

28 A MONOGRAPH OF THE ERYSIPHACEAE }

List OF NEW SPECIES AND VARIETIES
Uncinula salicis, var. Miyabei.
Uncinula Fraxini,
Uncinula Sengokut.
Microsphaera alni, var. ludens.

ERYSIPHACEAE Lév.

Parasitic on living (phanerogamic) plants ; vegetative mycelium
white, external to the host-plant, either (Erysipheae) forming haus-
toria in the epidermal cells, or (Phylactinieae)*sending special
branches for a short distance through the stomata into the inter-
cellular spaces, and from these branches sending haustoria into the
surrounding cells ; hyphae thin-walled, septate, much-branched
and interwoven ; conidia large, continuous (non-septate), colorless
or white, cylindrical, oblong, or barrel-shaped, produced singly or
in concatenate chains in basipetal succession on erect, simple,
septate, colorless conidiophores ; perithecia arising directly from
the mycelium, sessile, at first colorless, then yellow, becoming
finally brown or black, membranaceous, indehiscent, globose or
globose-depressed, sometimes becoming concave; walls many-
layered, pseudo-parenchymatous, the apical, equatorial or basal
cells of the outer wall usually giving rise to definite outgrowths,
the appendages, which are either more or less similar to the mycelial
hyphae, or quite distinct from them, and variously shaped, simple or
branched at the. apex, erect or radiating, sometimes colored ; asci

or many, arising from the base of the perithecium, colorless,
cylindrical, oblong, ovate or globose, frequently pedicellate, 2-8-
spored ; spores continuous (non-septate), colorless, oblong or oval,
with obtuse ends, straight or rarely slightly curved ; paraphyses

absent. )
Sub-family ERYSIPHEAE Palla. :

Mycelium wholly external to the tissues of the host-plant ;
sending haustoria into the epidermal cells only. Ze

: , Key to the Genera E

1. Ascus solitary. qu 3

Asci several. Se

2, Appendages of the perithecium basal, sometimes obsolete, not branched in a definite

er at the apex. | Sphaerotheca.

Appendages of the perithecium branched at the apex, or if unbranched, arising api-

_ cally. : 0 Podosphaera.

3. Appendages of the perithecium nearly always simple (branched in U, aceris (see

Fig. 87)), uncinate at the apex. ` Uncinula.
Appendages not uncinate.

wo

PODOSPHAERA 29

4. Appendages branched in a definite manner at the apex, or if unbranched Eu astra-
gali) white, assurgent and fasciculate. Tcrosphaera.
Appendages simple, or irregularly branched (no definite apical branching), some-
times obsolete, usually more or less similar to the mycelium, and rn with

it, very rarely ( Æ. Zortilis) brown, assurgent and fasciculate. rysiphe.

PODOSPHAERA Kunze, Myk. Heft. 2: 111. 1823

Perithecia globose, or globose-depressed ` ascus solitary, sub-
globose; spores eight. Appendages equatorial or apical, dark
brown or colorless, dichotomously branched at the apex, branches

mple and straight, or swollen and knob-shaped ; very rarely (P.
leucotricha) of two kinds, one set apical, brown, rigid, unbranched
or rarely 1—2 times dichotomous at the apex, the other set basal
short, flexuous, simple or vaguely branched, frequently obsolete.
Etym. zo'c, pes, and ogaroa, sphaera.—Distrib. Europe, Africa, n
North America, and probably Australia.—4 species and 1 varie

The single ascus separates the genus from all others of the pea
siphaceae except Sphaerotheca, from which it is at once distinguished
by the definite equatorial or apical appendages. P. leucotricha
which has hitherto been placed in the genus Sphaerotheca, and
known as S. mali, is anomalous among the Bd x in possess-
ing two kinds of appendages.

Key to the Species of Podosphaera :
I. Basal appendages send en appendages usually unbranched. 4. Ke com
Basal appendages >
Appendages erecto-fasciculate, springing from near the seni of the perithecium. .- 4.
E ages more or less spreading and equatorially ins 4.
3. Appendages 6-12 times the diameter of the oe a tees: or occasionally `

pale brown towards the bas 2. Schlechtendahi,
Appendages 1-8 times the FS of the perithecium, dark brown for more than
half their length. I. oxyacanthae var. tridactyla.

4. i colorless, or faintly tinged with brown at the base, branches of erg not

3. biun
Ner dark-brown for more than half their length, ultimate branches Se e
apex knob-s shaped. I. oxyacanthae.

1. PODOSPHAERA OXYACANTHAE (DC.) de Bary. [Figs. 96, 97, 99-
108, 115]

Erysiphe oxyacanthae DC., Mem. Soc. d’Agric. Depart. Seine
10:235. 1807; DC. Fl. Fr. 6: 106. 1815; Duby, Bot. Gall.
2:868. 1830; Dur. et Mont. Fl. d'Algér. (Crypt.) 564. Ad.
Tul. Sel. Te ‘Carp. I: 202, Së, SE e Ve

30 A MONOGRAPH OF THE ERYSIPHACEAE

Alphitomorpha clandestina var. oxyacanthae Wallr. Berl. Ges.
Nat. Freund. Verh.1:36. 1819; Wallr in Ann. Wett. Ges.
4:242. 1819; Wallr. Fl. Crypt. Germ. 2:754. 1833.

Sphaeria myriillina Schub.; Fon. Flor. Gegend. Dresd. 2:
356. 1823.

Podosphaera myrtillina Kze. and Schmidt, Myk. Heft. 2 : 113.
$4. 2. f. 8. 1823; de Bary, Beitr. Morph. Phys. Pilz. 1: $ XIII.
48. 1870 ; Sacc. Syll. Fung. 1: 2. 1882 ; Wint. in Rabenh. Krypt.
Fl. Deutschl. 1?:29. 1884; Karst. Act. Soc. Faun. Fl. Fenn.
25:95. 1885; Schroet. in Cohn's Krypt. Fl. Schles. 3°: 233.
1893; Jacz. Bull. l'Herb. Boiss. 4:744. 1896; Oudem. Rév.
Champ. Pays-Bas, 2:81. 1897.

Erysibe clandestina Lk. in Willd. Sp. Pl. 6: 103. 1824; Ra-
benh. Deutschl. Krypt. Fl. 1:237. 1844.

Erysiphe clandestina (oayacanthae) Fr. Syst. Myc. 3: 238.
1829.

E. myrtillina Fr. Syst. Myc. 3:247. 1829.

Erysibe myrtillina Rabenh. Deutschl. Krypt. Fl. 1:237. 1844.

Podosphaera-Kunzei Lév. Ann. Sci. Nat. III. 15: 135. AX. 6.
f. 6 (partim). 1851; Karst. Myc. Fenn. 2:198. 1873

P. clandestina LEV. Ann. Sci. Nat. III. 15: 36. ie cf. X
1851; Cooke, Handb. Brit. Fung. 2:648. 1871.

P. oxyacanthae (DC.) de Bary, Beitr. Morph. Phys. Pilz.
1:$ XIII. 48. 1870; Sacc. Syll. Fung. 1:2. 1882; Wint. in Ra-
benh. Krypt. Fl. Deutschl. 1’: 29. 1884; Earle, Bot. Gaz. 12:
26. 1884 (excl. syn. P. tridactyla and Alphit. tridactyla; Burr.
and Earle, Bull. Ill. State Lab. Nat. Hist. 412. f. 7 (syn. excl.
partim). 1887; Atkins. Journ. Elisha Mitch. Sci, Soc. 7 : 69.
1891; Burr.; Ell. and Everh. N. Amer. Pyren. 21. MX. 4 (syn. excl.
partim). 1892; Schroet; Cohn's Krypt. Fl. Schles. 3: 234
1893; Jacz. Bull. l'Herb. Boiss. 4:743. 1896; Oudem. Rev.
Champ. Pays-Bas. 2:79. 1897.

P. minor E. C. Howe, Bull. Torr. Club, 5:3. 1874; Sacc. Syll.
Fung. 9: 364. 1891.

© Microsphaera fulvofulcra Cooke, Grevillea, 5: 110. 1877;
Sacc. Syll. Fung. 1: 14. 1882, and 9: 364. 1891.

[P] Podosphaera clandestina Lév. var. ramulicola Thüm. Bull.

Soc. Imp. Nat. Mosc., 56: 126. 1882.

POoDOSPHAERA 31

P. aucupariae Erikss. Fung. par. scand. exsicc. no. 233 (cum
diag.) 1886; Sacc. Syll. Fung. 9: 364. 1891.

P. myrtillina var. major Juel. Ofvers. K. Oet. Akad. Förh.
51:496. 1895. ;

Exsicc.: Bri. and Cav. Fung. par. 215; Rab.-Wint. Fung. Eur.
3042, 3241, 3242, 3656; Syd. Myc. March. 1064, 1543, 2227,
*3559; Rehm. Ascom. 798, 900; Roumeg. Fung. Gall. Exsicc.
2735, 3736; Westend. Herb. Crypt. Belg. 280, 1057 ; and 740
sub Zrysiphe penicellata var. mespili ; Fckl. Fung. Rhen. 728, 729;
Desmaz. Pl. Cr. Fr. ed. 1: ser. 1: 919; and 1305 sub Zrysibe
penicellata var. mespili, *ser. 2: 919, *ed. 2: ser. 1; 219; and 705
sub Æ. penicellata var. mespili; Ell. and Everh. N. Am. Fung.
55, 55b, 2335; "Ell. and Everh. Fung. Columb. 107; *Sacc.
Myc. Ven. 1374; *Seym. and Earle, Econ. Fung. 126, 130,
132, 133, 418, 430; Lib. PL Cr. Ard. Fasc. 3. 278, Karst.
Fung. Enun. Exsicc. 277; de Thüm. Fung. Austr. 440, 446;
Rab. Fung. Eur. 566; *Wartm. and Schenk, Schweiz. Krypt.
628; *Gandog. Fl. Alger. Exsicc. 1984; *Erikss. Fung. par
scand. 32, 135; "Krieg. Fung. Saxon. 72.

Amphigenous, mycelium variable, sometimes persistent in
thin patches, at others wholly evanescent ; perithecia scattered to
more or less densely gregarious in clinging masses, subglobose,
64—90 p in diameter, cells 10-18 # wide; appendages spreading,
more or less equatorially placed, occasionally springing from nearer
the apex, extremely variable in number and length, from 4—30 in
number, and from 14-6, or rarely 10 times the diameter of the
perithecium, usually unequal in length on the same perithecium,
septate, dark brown for more than half their length, usually nearly
to the apex, becoming thick-walled throughout, with the lumen
more or less obliterated, apex 2—4 times dichotomously branched,
branches usually short and equal ( sometimes slightly elongated ),
ultimate branches rounded, swollen, and more or less knob-shaped ; -
ascus broadly obovate, broadly oblong, or subglobose, variable in
size, 58-90 x 45-75 #; spores normally 8, very rarely 6, varia-
ble in size, 18-30 x 10-17 f. e

Hosts.— Amelanchier Canadensis, Crataegus Azarolus (272), C.
coccinea, C. Crus-galli, C. Oxyacantha, C. rivularis, C. sanguinea
(350), C. spathulata, C. subvillosa (269), C. tomentosa and vars.
punctata and pyrifolia, Diospyros Virginiana (299), Prunus Ameri- `
cana, P. avium, P. Besseyi, P. Cerasus, P. Chicasa (324), P. de-

y A MoNOGRAPH OF THE ERYSIPHACEAE

missa, P. domestica, P. Pennsylvanica (382), P. Persica (382), P.
pumila, P. serotina, P. Virginiana, Pyrus Aucuparia, P. coronaria
(97) (137), P. Cydonia, P. Germanica, P. Malus, Spiraea betulifoha,
S. discolor (159), S. salicifolia, S. tomentosa, Vaccinium inter-
medium (319), V. Myrtillus, V. uliginosum.

Distribution. —Europe: Britain, France, Belgium, Nether-
lands (253), Germany, Switzerland, Italy, Austria-Hungary,
Denmark, Norway, Sweden, Finland, Russia. Africa: Algeria.
Asia : Siberia (Minussinsk) (350), Japan. North America : United
States—Maine (163), Vermont, Massachusetts, Connecticut, New
York, New Jersey (53), Virginia, North Carolina, Ohio (71) (324),
Michigan, Indiana, Alabama, Illinois, Wisconsin, Missouri, Iowa,
South Dakota, Nebraska, Kansas, Montana, Idaho, Utah (363),
Wyoming, Colorado, California. Canada—Ontario, New Bruns-
wick, Greenland (300).

Examination of a very large series of specimens has convinced
me that the plants hitherto known as Podosphaera oxyacanthae
and P. myrtillina are not specifically distinct. The distinguishing
characters relied upon have been these: P oxyacanthae, ap-
pendages 8 or more, shorter than or about equaling the diameter
of the perithecium ; P. myrtillina, appendages 4-10, spreading on
all sides, or even deflexed, 3 or more times exceeding the diameter
of the perithecium. In Europe these two forms, P. oxyacanthae
on Crataegus and Mespilus, and: P. myrtillina on Vaccinium Myriil-
lus and V. uliginosum, could perhaps, taken by themselves, be
kept distinct as varieties, for the distinctive characters are scarcely
of specific value, besides occasionally showing a tendency to fail. -
On dealing with other material, however, it is seen very clearly that
there exists every intermediate link between these two forms.

Let us take first the European form on Pyrus Aucuparia, de-
scribed by Eriksson as a new species. P. aucupariae, with the fol-
lowing diagnosis: “Hypophylla. Mycelium evanidum. Perithecia
sparsa, sphaeroidea, minuta. Appendices paucae (4-6), diametrum
perithecii ter superantes, e parte superiore perithecii radiatim diver-
gentes * * * Mea species P. aucupariae differt a P. oxyacanthae
appendicibus longioribus, a P myrtillina Kze. appendicibus
paucis, a P. tridactyla (Wallr.) de en appendicibus radiatis, ab
his utrisque peritheciis hypophyllis.

PoDOSPHAERA 93

In Eriksson's own specimens (Fung. par. scand. exsicc. nr.
233), however, the appendages measure 1% to 234 (averaging 2)
times the diameter of the perithecium. In the specimen in Rab.-
Wint. Fung. Eur. 3241 the appendages are slightly more unequal
in length, varying from 1-3 times the diameter of the perithecium.
As regards the number of the appendages, this is in Eriksson's
P. aucupariae 4-8, and in European specimens of P. myrtil/ina,
4-10.

On the whole, P. aucupariae connects P. oxyacanthae with
P. myrtillina, and cannot possibly be considered a separate
species.

It is, however, in dealing with American specimens that we see
how completely ** P. myrtillina” merges into P. oxyacanthae.

The American plant is often erroneously called " P. tridactyla `
by American mycologists, or P. Kunzei (which includes P. zridac-
tyla) is quoted wholly as a synonym; other authors, e. g., Earle
(110), have supposed that. the European P. myrtillina might be
something different from any of the American forms. As a matter
of fact, were the species P. oxyacanthae and P. myrtillina to be
kept distinct most the American forms would fall under the latter,
although occurring on other hosts than Vaccinium, while Z.
oxyacanthae would have to be confined to certain forms on Cra-
faegus, and to the form on Spiraea, which has been called P.
minor E. C. Howe.

A study of American examples on Crataegus, Prunus, P yrus,
Spiraea, etc., shows conclusively, however, that only a single
species exists, but one which is extremely variable in the length
and number of its appendages. Earle has some interesting re-
marks in his “Notes on the North American Forms of Podo-
sphaera” (110) on the subject of this variability, and this author's
conclusion that all the American forms must be included under the
single species P. oxyacanthae is undoubtedly correct. A specimen
in Professor Earle’s herbarium shows clearly how completely the
long- and short-appendaged forms are connected. This specimen
is labeled “on Crataegus, Deland, Illinois, Sept., 1889. A. B
Seymour.” Many of the perithecia are identical in the few short
appendages with those of the European P. oxyacanthae on Cra-
taegus Oxyacantha ; other perithecia show, quite gradually, an in-

34 A MONOGRAPH OF THE ERYSIPHACEAE

crease in both the number and length of the appendages, until they
cannot be separated from the more common long-appendaged
American form. P. minor Howe (Microsphacra fulvofulcra Cooke)
on Spiraca tomentosa also shows much the same variation in the
length of the appendages.

These short-appendaged forms show the range of variation of P
` oxyacanthae in one direction, in the other we meet with a very long
* appendaged form on Vaccinium uliginosum, which has been de-
scribed as ‘ P. myrtillina var. major Juel.’’’ Professor Juel has kindly
sent me a specimen (now in the Kew Herbarium) of this form, In
this specimen I find that contiguous perithecia have appendages vary-
ing from 2% to 10 times the diameter of the perithecium. I have
seen exactly the same form— with the appendages varying in
length from 6-10 times the diameter of the perithecium—in Rus-
sian specimens in Professor Tranzschel’s herbarium. As this
great variation occurs in perithecia on the same leaf, it is obviously
impossible to treat the length of the appendages as a character of
diagnostic value, and in other respects the form shows no differ-
ences.

In conclusion, it appears then that we must allow to the present
species—P. oxyacanthae—a range of variation in the length of its
appendages of from less than the diameter of the perithecium to
ten times exceeding it. The existence of a perfect series of con-
necting links justifies this treatment, as does also the fact that simi-
lar variation in the same characters is found in other species. In
the var. £ridactyla of the present species the appendages vary from
1-8 times the diameter of the perithecium. In the series of forms
of Microsphaera alni, the one long known as “ M. Hedwigii’’ cor-
responds exactly in the short, few appendages with the form of
P. oxyacanthae on Crataegus Oxyacantha and Mespilus, and my-
cologists now admit that “ M. Hedwigü’’ must be united with the
longer appendaged forms of M. alni.

In some examples of American P. oxyacanthae on Crataegus
the perithecia form densely matted patches about the midrib of the
leaf. Perhaps the plant described by Thümen (350) as Podosphaera
clandestina var. ramulicola is a similar form. The following de-
scription is given: “ Periitheciis dense aggregatis, numerosissimis,
pulviniformibus ; mycelio candido, non evanido ; ascis sporisque

PODOSPHAERA 35

typicis. In ramulis vivis Crataegi sanguineae Pall. in sylvis pr.
Minussinsk.

P. oxyacanthae is known in America as the ‘ Cherry Powdery
Mildew”’; also as the “ Apple Powdery Mildew,” although it is
possible that under the latter name P. /eucotricha is sometimes in-
tended.

Pammel (266 and 267) describing the “ Cherry Powdery Mil-
dew ” states that the disease can be treated successfully with Bor-
deaux mixture and ammoniacal carbonate of copper.

Galloway (136) speaking of an “ Apple Powdery Mildew,”
which was identified as the present species, states that it causes the
most serious injury to fruit trees, especially to the young stock of
nurseries. In one case, owing to the presence of the mildew, of
some stocks budded, only about two thirds of the buds took.
Full details are here given of the preparation and application of
the ammoniacal carbonate of copper, which was found perfectly
successful as a fungicide. The interesting statement is made that
“P. oxyacanthae probably winters in a mycelial stage.”

Benson (24) attributes a disease on apple trees, widely spread
over the colony of New South Wales, to “ P. Aunzei Lév.," and
recommends the diseased trees, when in bud, to be sprayed with `
Bordeaux mixture, followed with a dressing of ammonio-carbonate
of copper. As the fungus was, apparently, observed only in the
conidial stage, the identification with the present species remains
doubtful.

Waite (382) states of the present species that “ young cherry
trees are the chief. sufferers from its attacks, but it also does con-
siderable harm to the peach and to young apple trees in the nur-
sery, and occasionally seriously injures the quince." It is also
noted that the most destructive form of the fungus usually bears
but a few perithecia, and often fails to produce any before frost puts
an end to the season's growth. Spraying with a mixture of half an
ounce of potassium sulphide in a gallon of water is recommended.

P. oxyacanthae sometimes attacks Crataegus Oxyacantha so
severely that it kills the plant. Eriksson (119) records such cases
from the neighborhood of Stockholm, where young trees up to 4
feet high were destroyed. It is also stated that the fungus fre-
quently produces no perithecia on this host.

ie A MONOGRAPH OF THE ERYSIPHACEAE

Rose (299) records the occurrence of P. oxyacanthae on the
Persimmon (Diospyros Virginiana), and remarks that all the asci ex-
amined '* contained 9 spores, differing in this respect from any of
the species of Podosphaera.

Var. TRIDACTYLA (Wallr. [Figs. 109-114]

Alphitomorpha tridactyla Wallr. Fl. Crypt. Germ. 2: 753.
1833. i
A. (Erysiphe) Brayana Doith, Flora, 21: 475. pl. r. f. 7.
1838. |
Erysibe tridactyla Rabenh. Deutschl. Krypt. Fl. 1: 237. 1844.

E. Brayana Rabenh. Deutschl. Krypt. Fl. 1:237. 1844.

Erysibe tridactyla Desmaz. Ann. Sci. Nat. III. 3: 361. 1845.

Podosphaera Kunzei Lév. Ann. Sci. Nat. III. 15: 135 (partim).
1851; Cooke, Handb. Brit. Fung. 2: 647 (excl fig.). 1871.

Erysiphe tridactyla. Tul. Sel. Fung. Carp. 1: 201. pl. 4. f.
II-13. 1861.

Podosphaera tridactyla (Wallr.) de Bary, Beitr. Morph. Phys.
Pilz. r: $ XIII. 48. 1870; Sacc. Syll. Fung. 1: 2. 1882; Win.
in Rabenh. Krypt. Fl. Deutschl. 1?: 28. 1884; Karst. Act.
Soc. Faun. Fl. Fenn. 2:95. 1885; Schroet. in Cohn’s Krypt. Fl.
Schles. 3: 233. 1893; Jacz. Bull. Herb. Boiss. 4: 744. 1896;
Ouden. Rev. Champ. Pays-Bas. 2: 81. 1897.

Exsicc.: Sacc. Myc. Ven. 783; and 616 sub Uncinula Wail-
roth; de Thim. Fung. Austr. 122, 439 and 463 sub U. Wallro-
thi; Rehm. Ascom. 850; Rab. Fung. Eur. 565, 565b, 2412;
Rab. Herb. myc. ed. 2, 475 ; and 487 sub Zrysibe adunca var.
Pad Vize. Fung. Brit. 195; Fckl. Fung. Rhen. 726, 727 ; Des-
maz. Pl. Cr. Fr. ed. I, ser. 1, 1514,* 2194 and. fed, 2, ser. I,
1014, 844; Syd. Myc. March. 1141 ; Roumeg. Fung. Gall. exsicc.
1498; de Thiim. Myc. univ. 159; *Erbar. Critt. Ital. ser. 2,
494 ; Brit. & Cav. Fung. par. 292 ; * Erikss. Fung. par. scand. 136.

Amphigenous; mycelium usually evanescent, rarely subper-
sistent ; perithecia scattered to more or less densely gregarious,
subglobose, 70-105 (in diameter, cells 10-15 wide ` appendages
2-8, usually about 4, 1-8 times the diameter of the perithecium,
usually unequal in length on the same perithecium, springing in a
cluster from the apex of the perithecium, more or less erect, when
long often fasciculate, septate, dark brown for more than half their

PoDOSPHAERA 87

length, apex 3-5 (rarely 6) times dichotomously branched, primary
branches (and rarely the secondary) usually more or less elongated,
and sometimes slightly recurved, ultimate branches rounded,
swollen and more or less knob-shaped ; ascus globose or sub-
globose, 60-78 x 60-70 ; spores 8, 20-30 x 13-15 4, sometimes
slightly curved.

Hosts.—Prunus Armeniaca, P. communis, P. domestica, P.
insititia, P. Padus, P. spinosa, Spiraea Douglas [Pyrus Auca-
paria (319)].

Distribution. —Europe : Britain, France, Belgium (46, 209).
Netherlands (263), Germany, Switzerland (176), Italy, Austria-
Hungary, Denmark, Norway, Sweden, Russia. Asia: Japan.
North America: United States, Washington.

The apical insertion of the more or less erect, often fasciculate
appendages, together with a marked tendency for the apex of the
appendages to become more elaborately divided are the character-
istic features of the present plant. The apex of the appendages,
besides being more branched than in the type, frequently develops
long primary branches ; this latter character is not, however, abso-
lutely confined to the present variety, as it occurs rarely in examples
of P. oxyacanthae. Considering European specimens alone, it might
be contended that these characters are constant and important
enough to give a specific rank. Occasionally, however, amongst
these, examples occur in which a slight spreading tendency is
"shown in the appendages. This tendency is more marked in the
American example, which consequently forms a link with P.
oxyacanthae. \

Without exception all the American plants labelled “ P. Kun-
sei” (the name under which Léveillé united “ P. tridactyla ”
and “ P myrtillina’’) that I have seen, belong to P. oxyacanthae,
and the only specimen which belongs to the present variety is one
sent to me from the herbarium of the U. S. Dept. of Agric.
named “ Sphaerotheca humuli (DC.) Burr. on Spiraea Douglasit,
Seattle, Washington, Oct., 1891 (A. M. Parker)." In this specimen
(now in the Kew Herbarium) the long, more or less erect append-
ages springing from near the apex of the perithecium refer the
plant to the var. ¢ridactyla, and are quite different to the append-
ages of the form of P. oxyacanthae which occurs commonly on
American species of Spiraea. Nevertheless, in some perithecia

38° A MONOGRAPH OF THE ERYSIPHACEAE

the appendages here and there have a tendency to spread, and
thus show characters connecting P. oxyacanthae with its var.
tridactyla.

The published records of “P. tr wdactyla’’ (Wallr.) from Amer-
ica (53) (249) (366), etc., almost certainly all belong to P. oaya-
canthae, as the former name has been in error, commonly used by
American mycologists as a synonym of the latter species.

The Japanese plant occurs on Prunus communis, and was sent
to me by Professor Miyabe. The appendages are few, short, and
fasciculately erect, with a large very widely branched apex.

Schroeter’s (319) record of the occurrence of the present plant
on Pyrüs Aucuparia probably refers to P. oxyacanthae.

McAlpine (225) records “ P. tridactyla de Bary” on “young
leaves and shoots of Apple," from Victoriaand New South Wales,
but very probably this record rests merely on the occurrence of an
Oidium on this host, and the fungus may prove to belong to P.
leucotricha ; the Apple is not known as a host-plant for the var.
tridactyla.

In the present variety the length of the E cd varies
from 1-8 times the diameter of the perithecium, and there is also
great variation in the manner of the branching of the apex (see
Figs. 109-113).

2. P. SCHLECHTENDALII Lév. [Figs. 118, 123]

P. Schlechtendalii Lev. Ann. Sci. Nat. III. 15:29. X. 6. f. 7.
1861; Sace Syl Fung: 1: 3. 1882

Hypophyllous ; mycelium evanescent; perithecia scattered,
subglobose, 78—90 5; in diameter, cells 10-1 5 » wide; appendages
5-12, unequal in length, 6-12% times the diameter of the perithe-
cium, erecto-fasciculate, springing from the apex of the perithe-
cium, and forming a long flaccid, somewhat flexuous bundle,
which is more or less entangled in the hairs of the leaf, septate,
colorless above, occasionally pale brown towards the base, apex
2, very rarely 3 times dichotomously branched, end of ultimate
branches more or less thickened, primary and secondary branches
usually recurved; ascus subglobose, 76-84 x 68-74 4; spores 8,
23—28 x 13-15 u, sometimes slightly curved.

Hosts.— Salix alba (214), S. viminalis.

Distribution.—Europe : France.

There is a good specimen of this extremely interesting species

PODOSPHAERA 39

in Berkeley's Herbarium at Kew, sent to that author by Léveillé
himself. P. Schlechtendalii has apparently disappeared since its
discovery in 1851; I have seen no other example than the one
mentioned above, and it is very probable that the Kew specimen
is the only one in existence.

Quite lately (1897) Speschnew (338) has recorded 7 Schlech-
tendalii as occurring, rarely, on the willows of the islands of R.
Alazan, Transcaucasia. If the identification is correct, the reap-
pearance of this long-lost species in so distant a locality is very
interesting. ;

Léveillé (214, p. 137), found the original species at Neuilly,
near Paris, on the leaves of Salix alba and S. viminalis, and in his
description makes the following observations: ‘‘ Cette espéce, qui
n’a pas encore été signalée, est une des plus remarquables et des
plus faciles ä reconnäitre. Ses appendicules, au nombre de huit
ou dix, ont de dix ä onze fois la longueur du diametre des concep-
tacles, et leur extrémité présente des rameaux filiforme contournés
en vrille. Cette extrémité est assez difficile a voir; il faut beau-
coup de précautions pour la detacher, sans la briser, des poils qui
recouvrent la face inférieure des feuilles."

3. P. BIUNCINATA Cooke & Peck [Fig. 98]

P. biuncinata Cooke & Peck, Journ. of Bot. 1: 11. 1872; Peck,
Reg. Rep. 25: 94. 1873; Sacc. Syll. Fung. 1:3. 1882; Atkins.
Journ. Elisha Mitch. Sci. Soc. 7: 69. 1891; Burr. in Ell. and
Everh. N. Am. Pyren. 22. 1892.

Exsicc.: de Thüm. Myc. Univ. 2050; Ellis, N. Amer. Fung.
1326; Rab.-Wint. Fung. Eur. 3540; *Seym. and Earle, Econ.
Fung. 135 ; *Ell. and Everh. Fung. Columb. 509. `

Amphigenous ; mycelium persistent, arachnoid and effused, or
evanescent ; perithecia scattered, or often densely gregarious, sub-
globose, 55-72y in diameter; appendages 4-15, equatorially
placed and spreading, 3-5 times as long as the diameter of the
perithecium, straight or slightly flexuous, aseptate, smooth,
usually colorless throughout, sometimes with a faint tinge of
brown at the base, narrow (4-5 wide), thin-walled above, be-
coming thick-walled and refractive at base, apex once or rarely
twice dichotomously branched, primary - branches long or short,
more or less recurved ; secondary branches, when present, shorter,

40 A MONOGRAPH OF THE ÉRYSIPHACEAE

tips of ultimate branches straight, blunt; ascus globose, or sub-
globose, with a minute stalk, 45-50 x 40-48; spores 8, 20-24
x 11-13 f.

“This is a very distinct species. The branches at the tips of
the appendages are slightly curved, and diverge nearly at right
angles to the appendage. When mature, the plants often become
collected in entangled masses, giving the leaf the appearance of
being coated with dusty cobwebs” (Peck, Reg. Rep. 25: 95).

Host.—Hamamelis Virginiana.

Distribution.—North America: United States—Massachusetts,
Connecticut, New York, North Carolina, Ohio (71), Indiana, Ala-
bama (12), Illinois, Wisconsin. Canada—Ontario.
~ P. biuncinata is known at once by the long spreading colorless
appendages. The apex of the appendages is usually only once
forked, rarely the primary branches are again divided (see fig. 98).
I have once observed two asci in the same perithecium.

4. P. LEUCOTRICHA (Ell and Everh.) |Figs. 119-122]

Sphaerotheca leucotricha Ell. and Everh. Journ. Mycol. 4: 58.
1888 ; Sacc. Syll. Fung. 9: 365. 189r.

S. mali Burr. in Ell. and Everh. N. Amer. Pyren. 6 (excl.
syn. . Erysiphe mali Duby). 1892; Magnus, Bericht. Deutsch.
Bot. Gesell. 16: 333. a 27. 1898; Grout, Bull. Torr. Club,
26 : 374. Pl. 364. 1899. |

Albigo leucotricha (Ell. and Everh.) Kuntze, Revis. Gen. Plant.
F: Ee |

Exsicc.: *Syd. Myc. March. 3161, sub S. castagnei Lév.;
Warlich, Parasit. Pilz. 17, 18, sub S. castagnei Lév. (in Herb.
Hort. Imp. Petropol.).

Mycelium amphigenous, persistent, thin, effused ; perithecia
densely gregarious, rarely more or less scattered, 75-96 in di-
ameter, subglobose or sometimes slightly pyriform, cells 10-16 nm
wide, usually 10 ^; appendages of two kinds, one set springing
from the apex of the perithecium, the other inserted basally ;
apical appendages 3-11 in number, usually 3-5, more or less
widely spreading, or erecto-fasciculate, 4-7 times the diameter of
the perithecium, septate when young, becoming thick-walled, with
the lumen more or less obliterated, colored dark brown in the
lower half, paler towards the tip, apex undivided and blunt, or
rarely once or twice dichotomously divided ; basal appendages

PODOSPHAERA 41

sometimes nearly obsolete, sometimes well-developed, short, more
or less tortuous, pale brown, simple or irregularly branched ; ascus
oblong to subglobose, 55-70 x 44-50 #; spores 22-26 x 12-14
nm, crowded in the ascus.

Hosts.—Pyrus Malus, P. Sieboldi.

Distribution.—Europe : Germany, Austria-Hungary (Tyrol),
Russia (Tauria. Asia: Japan. North America: United States :
Vermont, Wisconsin, Mississippi (60), Iowa, Missouri (117), Kan-
sas (154).

In its characteristic form this species, when in fruit, produces
matted patches on the young stems of the apple, occasionally
occurring on the petioles or very rarely scattered on the leaves.
The patches of densely compacted perithecia among the persistent
mycelium, from their long, more or less erect rigid appendages,
give a densely hirsute appearance to the infected stem. These
apical appendages are, however, apparently very deciduous.

The present species was first described in 1888 as Sphaerotheca
leucotricha by Ellis and Everhart (117). Burrill (60), in 1892
changed the name to S. mali (Duby), identifying it with the Zry-
siphe mali of that author. Burrill remarked as follows: “ This
exceedingly interesting species has not been well separated from
Podosphaera oxyacanthae which occurs on the same host, and to
casual observation has much the same appearance. In our species
the tips of the large appendages are occasionally forked (once or
even slightly twice), which again may have been confusing. But
these vague stiff branches are totally unlike the dichotomous divi-
sions of Podosphaera, and otherwise the species are very distinct.
The tuft of short, interwoven, rudimentary appendages, like a dense
cluster of short roots, is a very characteristic mark.” — Duby's
Erysiphe mali Bot. Gall. 2 : 869, however, is not the present spe-
cies but is Phyllactinia corylea, as an examination of the type in
Duby's herbarium at the University of Strasburg showed.

From the study of many examples of the present plant, in-
cluding authentic specimens kindly sent by Professor Ellis, I am
led to refer the fungus to the genus Podosphaera rather than to
Sphazrotheca. The apical appendages are quite different from
anything found in the genus Sphaerotheca, while similar in struc-
ture and insertion to those of Podosphaera oxyacanthae var. tri-

42 A MONOGRAPH OF THE ERYSIPHACEAE

dactyla, to which plant I consider P. leucotricha to be most nearly
allied. From all known species of Zrysipheae the present plant
differs in possessing two kinds of appendages, and suggests, I think,
the manner in which Sphaerotheca may have arisen from some
such genus as Podosphaera. In the present species there are signs
that the more specialized apical appendages are beginning to die
out, as is shown by the fact that these only rarely develop to the
stage of forking, commonly remaining undivided and blunt at the
apex. On the other hand, the Sphaerotheca-like basal appendages
have already appeared. These are sometimes obsolete, sometimes
well developed and densely clustered.

P. leucotricha was known only from North America, until
Magnus (228) recently reported it from the Tyrol. It appears
certain, however, that it is really quite common in parts of Europe
in the Oidium stage on the young stems and buds of apple, but
that it has been passed over on account of the fact that it only very
rarely produces perithecia. Professor Magnus kindly sent me his
specimens from the Tyrol for examination, and I found them to
agree perfectly with American examples.

Quite similar to the Tyrolese specimens are Russian ones
which I have found contained in the Herbarium of St. Petersburg,
under the name of Sphaerotheca castagnei (W. Wahrlich, Parasit,
Pilze, 17 and 18); this is also the case with the specimens (simi-
larly named) from Germany issued in Syd. Myc. March. no. 3161.

P. leucotricha has also occurred among the Japanese Erysiph-
aceae sent to me by Prof. Miyabe. This example (now in the
Kew Herbarium) is growing on Pyrus Toringo (P. Sieboldi), and is
without doubt the same as the American and European species.
The apical appendages are here sometimes very poorly developed,
or even apparently absent, sometimes long and characteristic ; the
curious root-like basal appendages are developed prominently.
The perithecia are clustered in the characteristic manner, forming
‘blackish masses on the persistent white powdery mycelium. This
occurrence, besides adding Asia to the range of distribution, gives
a new host-plant for the species.

P.-leucotricha is so prevalent in some parts as to form a disease.
Pammel (267) says “In some parts of the United States apple
seedlings are seriously affected with this disease. It rarely affects

PoDOSPHAERA 43

old trees but is especially common on “suckers,” coming up
around large trees in the orchard and nursery." Ammoniacal
carbonate of copper and Bordeaux mixture were found efficacious
as fungicides. It is probable that the common American “apple
powdery mildew " disease, generally attributed to P. oxyacanthae,
is in many cases caused by the present species.

Sorauer has given an account in Hedwigia (332) of a mildew
disease of apple trees, in which the fungus is identified as
“ Sphaerotheca Castagnei Lév. f. mali." Professor Sorauer kindly
sent mea series of microscopical slides of this mildew, and in these
the characteristic perithecia of the present species are clearly to
be seen. The thick-walled septate rigid appendages are wrongly
described in Hedwigia as being basal. They are in reality (as the
specimens show) apical ; most of the perithecia possess also the
characteristic root-like basal appendages. Professor Sorauer (loc.
cit.) gives some interesting details of the manner in which the
fungus attacks the apple trees, and mentions that, in severe cases,
the weaker shoots of the tree are killed. It is also stated that a
hibernation of the mycelium takes place on the young shoots.

Cobb (73, p. 279) gives an account of a disease prevalent in
Australia, called the “ powdery mildew of the apple." No peri-
thecia were found by the author, although the fungus is referred
to * P. Kunzei Lév." It is, however, more probable from the de-
scription that P. /eucotricha is the cause of the disease. Some in-
teresting information is given, as follows: “No account of the
diseases of the apple would be complete without mention of the
powdery mildew which does so much damage to young apple-
trees (especially seedlings) in nurseries. In Australia the disease
is by no means confined to nurseries. I have repeatedly had ex-
amples sent in from trees two, three, and four years old; in fact,
orchardists send in this disease oftener than any other apple disease,
scab excepted ; so there can be no doubt that it is a plague o.
them as well as to nurserymen. * * * The leaves near the ends of
the branches are the first to go.” Spraying with ammonio-car-
bonate of copper or Eau Celeste is recommended.

Although P. /eucotricha is at present supposed to be a rare
species, it will very probably prove to be widely distributed and
common, and has most likely been hitherto passed over by my-

44 A MONOGRAPH OF THE ERYSIPHACEAE

cologists on account of the peculiarity it possesses of very rarely
forming perithecial fruit; in its conidial stage it is probably fre-
quently recorded as P. oxyacanthae. It will probably be found to.
occur in Britain, although I have not at present seen an example.
It is very probable that what has been known as Oidium farinosum
Cooke will prove to be the conidial stage of the present species.
This Odium is not uncommon on apples in some parts of England,
and attacks especially the young leaves and leaf-buds, causing the
leaves to fall prematurely and hindering or completely Hee
the formation of young wood.

A good account and figure of P. leucotricha has been recently
given by Grout (154) in the Bull. Torr. Club.

SPHAEROTHECA Lév. Ann. Sci. Nat. III. 15: 138. 1851*

Perithecia subglobose, ascus solitary, 8-spored. Appendages
floccose, brown or colorless, potrei Serien im and often i in-

* Kuntze (207) h jl tt CAL "mA f
ust give way to the nasties name A/bigo. Kuntze tem: Albigo Steud. s Ehrh. fe
disces. (1824) oe 52 and 54 = Sphaerotheca Lév. 1851. Es ist en humuli
Alphi-

Steu l. ** Ehrh.” = Albigo macularis SE Nom. 270. **Ehrh. in sched.’

tomorpha macularis humuli Wall. * * * Albigo ist zwar ein nome nudum,
scheint mir aber sicher recognoscirbar.’’ Kuntze then proceeds to transfer to Stee
all the species of SORTA mentioned in Saccardo’s Sylloge. Magnus (232) has
criticised the above statements and expressed the opinion that the name Aldigo has no

claim to be adopted, but has Geet that perhaps the name Sphaerotheca macularis
(Ehrh.) ought to be employed in the place of S. kumuli DC.

Neither Kuntze nor Magnus, ee reached ves origin of the name Albigo.
This is found in Ehrhart’s Beitr. zur Naturkunde, 7 : 84. 1792, where the following
description is given: ** Mehlthau — mihi zum Unterschied von der Rubigine
(Rost, Rótheln, Karfaugel) * ist ein bipes staubartiges Wesen, welches
gewöhnlich auf der untern Seite der Blätter des Hopfens, der Erbsen, und mehreres
Pflanzen, sitzet, und zur Zeit der Réife hin und wieder mit kleinen, schwarzen Kügel-

uet ist.” Ehrhart concludes p vn that this substance is really a fun-

—“ ind zwar der Mucor Erysiphe .ist. Wer ihn aus diese gegen
nicht kennen lernen kann, der eg: meine Plantas cryptogamas 100,
wo er getrocknete Exemplare davon finden wird." M. P. Sydow kindly aee

* for me the copy of Ehrhart's Exsiccati in the Berlin Museum, and informs me that the
specimen No. 100 is labelled merely Mucor Erysiphe Linn. No mention of Aigo
occurs, nor is any diagnosis given. As Ehrhart's remarks quoted above show, this
author used the word 4/^;go in a quite general sense for all BÉ ve we it
nowhere defined as a genus. Consequently, there are no grounds for substituting this
name for Léveille's Sphaerotheca. The name ** S. macularis ee p ” which Magnus
has supposed should n werten that of Aumuli DC. for the Hop Mildew, has
also no claim to be recogni

SPHAEROTHECA 45

terwoven with the mycelium, simple or vaguely branched ; fre-
quently obsolete. Etym. syapa, sphaera, and Önxn, theca.

Distribution. —Europe, Africa, Asia, Australia, North and South
America— 5 species and I variety.

The single ascus and floccose appendages, more or less re-
sembling the mycelial hyphae, separate Sphaerotheca from all other
genera. The most interesting features shown are the production
of special thick-walled, interlaced hyphae from the vegetative
mycelium, forming a persistent pannose covering for the more or
less immersed perithecia (S. pannosa, S. lanestris, etc.) and the
complete separation of the inner wall of the perithecium from the
outer, which takes place is some species (S. phytoptophila, S. lanes-
tris). S. phytoptophila only occurs, apparently, in association with
a species of gall-mite (Phytoptus).

Key to the Species of sphaerotheca

. Mycelium persistent, thick, pannose, forming dense patches composed of special hy-
ae, in which the perithecia are more or less immersed. Gs
Mycelium without these characters. *

to

. Persistent mycelium usually satiny and shining, white, sometimes becoming gray or
pale brown 2. pannosa.

Persistent mycelium dark brown.

3. Inner wall of perithecium separating from the outer, hyphae of persistent myceliur
very tortuous. 4- lanestris.
Inner wall not separating, hyphae straighter. 3. mors-uvae.
4. Perithecia-60-78 u in diameter, ascus 60-75 X 42-50 u, inner wall of perithecium
separating from the outer. 5. phytoptophila.
Perithecia 50-120 u in diameter, ascus 45-90 X 507724 ; inner wall scarcely sepa-

|. rating. >

5. Cells of outer wall of perithecium 10-20 wide, averaging I5 #- 8 humuli,
Cells 20-30 (rarely 40) u wide, averaging 25 A. I. humuli, var. fuliginea.

1. SPHAEROTHECA HUMULI ( DC.) Burr. [Figs. 116, 117}.

Mucor Erysiphe Linn. Sp. Pl. 2: 1186 ( partim). 1753.

Sclerotium Erysiphe Pers. Obs. Myc. 1:13 (partim). I 796 ;
Pers. Syn. Fung. 124 (partim). 1801.

Erysiphe hitmuli DC. Fl. Fr. 6:106. 1815; Duby, Bot. Gall.
2:868. 1830; Tul. Sel. Fung. Carp. 1 : 211. pl 4. /. 9. 1861.

E sanguisorbae DC. Fl. Fr. 6: 108. 1815; Duby, Bot. Gall.
2:868. 1830. +

46 A MONOGRAPH OF THE ERYSIPHACEAE

Alphitomorpha macularis Wallr. Berl. Ges. Nat. Freund. Verh.
1:35 (partim). 1819; Wallr. Fl. Crypt. Germ. 2:756. 1833.

A. clandestina, var. alchemillae Wallr. Berl. Ges. Nat. Freund.
Verh. 1: 36. 1819.

A. ferruginea Schlecht. Berl. Ges. Nat. Freund. Verh. 1 : 47.
1819.
. aphanis Wallr. Ann. Wett. Ges. 4:242. 1819.
. humuli Wallr. Ann. Wett. Ges. 4: 243. 1819.
. epilobii Wallr. Ann. Wett. Ges. 4: 243. 1819.

Erysibe macularis, var. humuli Fon, & Schub. Fl. Gegend,
Dresd. 2: 304. 1823.

E. macularis Schlecht. Fl. Berol. 2:168. 1824. Rabenh.
Deutschl. Krypt. Fl. 1:231. 1844. |

E. humuli Lk.; Willd. Sp. Pl. 6: 10]. 1824.

E. epilobii Lk.; Willd. Sp. Pl. 6:102. 1824.

E. fuliginea Lk.; Willd. Sp. Pl. 6: 102 (partim). 1824 ; Ra-
benh. Deutschl. Krypt. Fl. 1: 230 (partim). 1844.

E. ferruginea ( poterti ) Lk: Willd. Sp. Pl. 6: 103. 1824.

E. aphanis Lk: Willd. Sp. Pl. 6: 104. 1824.

Erysiphe alchemillae Grev. Fl. Edin. 460. 1824.

E. macularis Fr. Syst. Myc. 3: 237. 1829.

E. fuliginea Fr. Syst. Myc. 3: 238 ( partim). 1829.

E. ferruginea Fr. Syst. Myc. 3: 238. 1829.

E. communis Fr. Syst. Myc. 3: 239 (partim). 1829.

E. poteri Duby, Bot. Gall. 2: 868. 1830.

E. alchemillae Duby, Bot. Gall. 2: 870. 1830.

Erysibe alchemillae Desthaz. Pl. Cr. Fr. ser. 1, no. 517. 1831.

Alphitomorpha horridula, var. spiraeacearum and dryadearum
Wallr. Fl. Crypt. Germ. 2: 756. 1833.

Erysibe potentillae Lib. Pl. Crypt. Ard. fasc. 3, no. 279. 1834.
E. horridula Rabenh. Deutschl. Krypt. Fl. 1:235 (partim).
1844. |
Erysiphe erodii Dur. & Mont. Fl. d'Algér. (Crypt.) 567 (excl.
syn.) 1846-9 ; Mont. Syll. Crypt. 253. 1856; Sacc. Syll. Fung.
&:20; 1902.

E. glomerata Mer. Addit. Rev. Fl. Par. 497. 1847.

Sphaerotheca Castagnei Lév. Ann. Sci. Nat. III. 15: 139. pl. 6.
f. 9, 10, ro’ (partim). 1851; Cooke, Micr. Fung. 218. A. rz. f.

Qa Hh od

SPHAEROTHECA 47

216 (partim). 1865; Cooke, Handb. Brit. Fung. 2: 645. f.
312 (partim). 1871; Karst. Myc. Fenn. 2: 197 (syn. excl. par-
tim). 1873; Sacc. Syll. Fung. 1:4 (partim). 1882; Wint;
Rabenh. Krypt. Fl. Deutschl. 1?:27 (partim). 1884; Karst.
Act. Soc. Faun. Fl Fenn. 2:94 (partim). 1885; Jacz. Bull.
Herb. Boiss. 4: 725 (partim). 1896; Oudem. Rev. Champ.
Pays.-Bas. 2: 83 (partim). 1897.

Erysibe horridula, var. ulmariae Desmaz. Pl. Cr. Fr. ed. I, n.
2196; ed. 2, n. 1846, and Ann. Sci. Nat. III. 18: 370. 1852.

Erysiphe dipsacearum Tul. Sel. Fung. Carp. 1: 210. Pl. 4. Fi
4-8 (syn. excl. partim). 1861.

Podosphaera epilobii De Bary, Beitr. Morph. Phys. Pilze t:
§ xii. 48. 1870.

Sphaerotheca pruinosa Cooke & Peck, Journ. of Bot. I: IT.
1872; Peck, Reg. Rep. 36: 94. 1873; Sacc. Syll Fung. 1: 3.
1882; Burr. & Earle, Bull. Ill. State Lab. Nat. Hist. 2: 399.
1887 ; Burr; Ell. & Everh. N. Amer. Pyren. 5: 1892.

S. Niesslii Thuem. Verh. k. k. zool.-bot. Gesell. Wien, 29:
524. 1880; Sacc. Syll Fung. 1: 4. 1882; Wint.; Rabenh.
Krypt. Fl. Deutschl. 17: 28. 1884.

S. epilobii (Lk. Sacc. Syl. Fung. I: 4 1882; Wint.;
Rabenh. Krypt. Fl. Deutschl 17: 27. 1884; Karst. Act. Soc.
Faun. Fl. Fenn. 2: 95. 1885; Burr. ; Ell.and Everh. N. Amer.
Pyren. 8. 1892 ; Schroet. ; Cohn's Krypt. Fl. Schles. 3: 232. 1893.

S. fugax Penz. and Sacc. Att. R. Instit. Ven. VL: 23519.
1884; Sacc. Syll. Fung. Addit. ad vol. I-IV: 1. 1886 ; and
9: 365, 189r.

S. humuli (DC.) Burr. Bull. Ill. State Lab. Nat. Hist. 2:
400. 1887; Burr; Ell. and Everh. N. Amer. Pyren. 5. 1892.

Albigo humuli * Ehrh.” Steud., Kuntze, Revis. Gen. Plant. 3°:
442. 1892.

A. epilobii (Lk.) Kuntze, Revis. Gen. Plant. 3°: 442. 1892.

A. fugax (Penz. and Sacc.) Kuntze, Revis. Gen. Plant. 3°:
442. 1892. ;

A. Niesslü (Thuem.) Kuntze, Revis. Gen. Pit 3°: 442
1892.

A. pruinosa (Cke. and Peck) Kuntze, Revis. Gen. Plant. 3°:
442. 1892.

48 A MonoGRAPH OF THE ERYSIPHACEAE

S. humuli (DC.) Schroet.; Cohn's Krypt. Fl. Schles. 3: 231
(partim). 1893.

Exsicc.: Klotzsch, Herb. Myc. 63, and spec. sub Erysiphe
communis, var. geranit; Rehm. Ascom. 250; Cooke, Fung. Brit.
Exsicc. 91 ; ed. sec. 590; Roumig. Fung. select. exsicc. 4840,
5622; Speg. Dec. Myc. Ital. 40; Rab. Fung. Eur. 557, 558,
1047, 1049, and 1430 sub E communis; Syd. Myc. March.
1075,:2660, 2661, *3724, *4245 ; Sacc. Myc; Ven. 627, 628;
de Thuem. Fung. Austr. 235, 443, 654, 755, and 1239 sub E
communis; de Thuem. Myc. univ. 960, 1540, and 2056 sub £.
lamprocarpa ; Fl. Exsicc. Austro-Hungar. 380 ; Westend. Herb.
Crypt. Belg. 407, 829; Desmaz. Pl. Cr. Fr. ed. 1, ser. 1, 165,
517, 1113, 1302, 1303, and 2196 sub Arysibe horridula ?, *ed. 2,
Ser. 1, 513, 702, 703, 812, 1846 ; Fckl Fung. Rhen. 711, 712,
713, 718, 721, 2234, 2235; Oudem. Fung. Neerl Exsicc. 72;
Rab. Herb. Myc. ed. 2, 460, 468, and 481 sub Zrysibe horridula ;
Roumeg. Fung. Gall. Exsicc. 640, and 3517, 3742, sub E com-
munis; Ayres, Myc. Brit.; Jack, Lein. and Stitzenb. Krypt. Bad.
033,827; Lib. PL Crypt Ard. fasc. 3, 279 ; and fasc. 4, 381;
Rab.- Wint. Fung. Eur. 3041 ; Berk. Brit. Fung. 313, sub Zrysiphe
communis ; Karst, Fung. Fenn. Exsicc. 278 ; Vize Fung. Brit. 91,
sub Sphaerotheca pannosa ; Rab.-Wint.-Patzsch. Fung. Eur. 3856;
Erbar. Critt. Ital. ser. 1, 143, ser. 2, 1067; Ell. N. Amer. Fung.
557c; *Erikss. Fung. par. scand. 137a, 137b, 138, 234a, 234b;
*Seym. and Earle, Econ. Fung. 278, 432, and 131a, sub Sphaero-
theca pannosa; *Wartm. and Schenk, Schweiz. Krypt. 321;
*Kneiff. and Hartm., Pl. Crypt. Bad. 158; *Cav. Fung. Long.
Exsicc. 30; *Romell, Fung. exsicc. praes. scand. 60.

Amphigenous ; mycelium usually evanescent, but sometimes
persistent, and forming white orbicular spots or irregular patches
on the upper surface of the leaf ; perithecia’ usually somewhat gre-
garious, but varying from scattered to densely gregarious or even
caespitose, 58-120 win diameter, cells small, averaging 15 » wide,
but varying from 10-20 nu wide ; appendages very variable, few or
numerous, usually long, often exceeding 9 times the diameter of
the perit thecium, more or less straight, septate and colored dark
brown throughout, but sometimes short, tortuous, interwoven and
pale brown, sometimes even obsolete, very rarely flexuose and
more or less shining white throughout; ascus broadly elliptical

*

SPHAEROTHECA 49

to subglobose, rarely shortly stalked, 45-90 x 50-72 4; spores 8,
20-25 (rarely 30) x 12-18 p, averaging 22x15 f

Hosts — Agrimonia Eupatoria, Alchemilla arvensis, A. vulgaris,
Collomia gracilis, C. heterophylla, C. linearis, Dipsacus laciniatus,
D. sylvestris, Epilobium adenocaulon, E. alpinum, E. cephalostigma,
E: coloratum, E. hirsutum, E. jucundum, E. montanum, E. palustre,
E. parviflorum, E. parvifforum X roseum, E. pubescens, E. roseum,
Erodium moschatum, Fragaria glauca, Geranium caespitosum, G.
Carolinianum, G. Ibericum, G. incisum, G. maculatum, G. Nepa-
lense, G. palustre, G. pratense, G. Richardsoni, G. sylvaticum,
Geum album, G. Kokanicum, G. macrophyllum (265), G. strictum,
G. Virginianum, Gilia aristella, G. heterophylla, G. linearis, Humu-
lus Japonicus, H. Lupulus, Morina persica, Neillia opulifolia, Phlox
longifolia, Potentilla Anserina, P. bifurca, P. Comarum, P. fragari-
oides, P. glandulosa, P. palustris, P. reptans, P. Tormentilla, Pote-
rium Canadense and var. medium, P. officinale and var. carneum, P.
Sitchense (cult.), P. tenuifolium and var. album, Pyrus Aria, Rhus
copallina, R. glabra, R. typhina (60) (282), Ribes floridum, Rosa
Arkansana, R. blanda, R. lucida, R. Woodsii, Rubus Canadensis, R.
hispidus, R. odoratus, R. spectabilis, R. strigosus (60), R. triflorus,
Scabiosa Caucasica, Shepherdia argentea, S. Canadensis, Spiraea
Aruncus, S. Camtschatica, S. salicifolia (163), S. Ti hunbergit, S. Ul-
maria, Viola Canadensis, V. canina var. sylvestris.

Distribution —Europe: Britain, France, Spain and Portugal
(77), Belgium, Netherlands, Switzerland, Italy, Germany, Austria-
Hungary, Denmark, Norway, Sweden, Finland, Russia. Africa:
Algeria. Asia: Transcaucasia (338), Turkestan, Siberia (Minus-
sinsk), Japan. North America: United States—Maine (163), New
Hampshire (124), Massachusetts, New York, Pennsylvania, New
Jersey, Virginia, South Carolina, Ohio, Michigan, Indiana, Ala-
bama (12), Tennessee, Illinois, Mississippi, Wisconsin, Missouri,
Iowa, Minnesota, South Dakota, Nebraska, Montana, Wyoming,
Colorado, Utah, California, Washington, Canada, Newfoundland,
New Brunswick, Ontaria.

- Var. fuliginea (Schlecht)

Alphitomorpha fuliginea Schlecht. Berl. Ges. Nat. Freund.
Verh. 1: 47.. 1819.

50 A MONOGRAPH OF THE ERYSIPHACEAE

Erysibe fuliginea Lk. ; Willd. Sp. Pl. 6: 102 (partim). 1824;
Rabenh. Deutschl. Krypt. Fl. 1: 230 (partim). 1844.

Erysiphe fuliginea Fr. Syst. Myc. 3: 238 (partim). 1829.

E. communis Fr. Syst. Myc. 3: 239 (partim). 1829.

E. fusca Fr. Syst. Myc. 3: 242. 1829.

E. lamprocarpa, var. plantaginis Duby, Bot. Gall. 2: 869
(partim). 1830.

E. doronici Duby, Bot. Gall. 2: 870. 1830.

Alphitomorpha lamprocarpa, var. balsaminae Wallr. Fl. Crypt.
Gerni. 2: 758. : 1833.

A. communis, var. personatarum Wallr. Fl. Crypt. Germ. 2:
758 (partim). 1833.

A. fumosa Wallr. Fl. Crypt. Germ. 2: 760 (syn. excl. partim).
1833.

Erysiphe gerardiae Schwein. Syn. Fung. Am. Bor. 269. 1834;
Sácc. Syll. Fung. 1: 22. 1882.

E. erigerontis Canadensis Lév.; Mer. Supp. Rev. Fl. Par. 459.
1843.

Erysibe lamprocarpa, var. balsaminae Rabenh. Deutschl. Krypt.
FL 17232, —1844.

E. communis Rabenh. Deutschl. Krypt. Fl. 1: 232 (partim ).
1844.
E. circumfusa Rabenh. Deutschl. Krypt. Fl. 1 : 232 ( partim ).
1844.

E. fusca Fr. Rabenh. Deutschl. Krypt. Fl. 1: 235. 1844.

Erysiphe plantaginis Cast. Cat. Pl. Mars. 188. 1845.

E. xanthii Cast. Cat. Pl. Mars. 188. 1845.

Sphaerotheca Castagnei Lev. Ann. Sci. Nat. III. 15: 139. pi. 6.
J 9, 10, ro’ (partim). 1851; Cooke, Micr. Fung. 218. ai rz. f.
216 (partim). 1865; Cooke, Handb. Brit. Fung. 2: 645. f. 372
(partim). 1871; Syll Fung. 1:4 (partim). 1882; Wint.;
Rabenh. Krypt. Fl. Deutschl. 17: 27 (partim). 1884; Karst. Act,
Soc. Faun. Fl. Fenn. 2: 94 (partim). 1885; Burr. & Earle, Bull.
Ill. State Lab. Nat. Hist. 2: 400. f. 3. 1887; Atkins. Journ.
Elisha Mitch. Sci. Soc. 7: 64. 1891; Burr.; Ell. & Everh. N.
Amer. Pyren. 8. ar 1892; Jacz. Bull. l'Herb. Boiss. 4: 725
(partim). 1896; Oudem. Rév. Champ. Pays.-Bas. 2: 83 (partim),
1897. :

A

SPHAEROTHECA 51

Erysiphe detonsa Westend. (non Fr.) Bull. Acad. Roy. Belg.
18:403. M. 1.3. 1851.

Sphaerotheca detonsa Kickx. Fl. Crypt. Fland. 1: 375. 1867.
Lamb. Fl. Myc. Belg. 2:175. 1880; Sacc. Syll. Fung. 1:4.
1882 ; Oudem. Rev. Pyren. 11. 1884.

Podosphaera Castagnei (Lév.) de Bary, Beitr. Morph. Phys.
Pilz. 1: § xiii. 48. 1870.

Erysiphe fuscata Berk. & Curt. Grevillea, 4: 159. 1876 ; Sacc.
Syll Fung. 1: 19. 1882.

Sphaerotheca drabae Juel, Bot. Notis. 9. 1890; Sacc. Syll.
Fung. 9: 366. 1891; Juel, Bot. Centralbl. 45: 274. 1891;
Juel. Ófvers. K. Vet. Akad. Förh. (Stockholm), 496. 1895.

Meliola (Meliopsis) calendulae Malb. & Roum. Rev. Myc. 7:
go. 1886.

Sphaerotheca calendulae (Malb. & Roum.) Malb. Bull. Soc.
Myc. France, 4: xxxii 1888; Sacc. Syll. Fung. 9: 366.
1891.

Albigo calendulae (Malbr. & Roum.) Kuntze, Revis. Gen.
Plant: y- 442. 1892.

A. drabae (Juel) Kuntze, Revis. Gen. Plant. 3°: 442. 1892.

Sphaerotheca humuli (DC.) Schroet. in Cohn’s Krypt. Fl.
Schles. 3: 231 (partim). 1893.

S. Castagnei, var. submutica Juel Öfvers. K. Vet. Akad. Förh.
(Stockholm), 51 : 497. 1895.

S. erigerontis Oudem. Rev. Champ. Pays.-Bas. 2: 84. 1897.

Exsıcc.: Fckl. Fung. Rhen. 714, 715, 716,717, 720, 722, 724,
1745, and 651 sub Zrysiphe lamprocarpa; Rab. Fung. Eur.
1046, 1046b, 1050, 2026, 2414, and 580 sub Sphaerotheca pan-
nosa Bon., and 1058, 2034 sub Zrysiphe lamprocarpa ; Westend.
Herb. Crypt. Belg. 281, 555, 1056; and 972 sub £. communis ;
Rab. Herb. Myc. ed. 2. *459, 484 sub Erysibe communis, and
458 sub|£. /amprocarpa ; de Thuem. Myc. univ. 556, 1839; Syd.
` Myc. March. 194, 297, 833, 834, 1140, 1239, 1542; and 1639,
sub Erysiphe communis ; and 286 sub E. /amprocarpa ; ard 1147,
*3719 sub E cichoracearum ; Roumeg. Fung. Gall. exsicc. 1537,
' 2168, 2657, 2741, 3658, 3739; and 1982, 1985 sub E com-
munis ; Desmaz. Pl. Cr. Fr. ed. 1, ser. 1, 761 sub Zrysibe persona-
torum; and 1304 (A only) sub Æ. communis; ser. 2, 673 ; Sacc.

52 A MONOGRAPH OF THE ERYSIPHACEAE

Myc. Ven. 145, *630, 631, 632, 633, 629, 899, 1375, 1376, 900,
901; and 611 sub Lrysiphe lamprocarpa; Kunze, Fung. select.
exsicc. 574 ; Jack. Lein. & Stizenb. Krypt. Bad. 828 ; de Thuem.
Fung. austr. 123, 442, 444, 653, 756; Oudem. Fung. Neerl.
exsicc. 272; Speg. Dec. Myc. Ital. 83, 83 bis; Rehm. Ascom.
544, 545, 600, 750; and 450 sub? E communis; Erbar. Critt.
Ital. ser. 1, 878, ser 2, 1068; Rab.-Wint. Fung. Eur. 3657 ;
Cooke, Fung. Brit. exsicc. ed. sec. 595 sub E /amprocarpa ;
Kneiff. & Hortm. Pl. Crypt. Bad. 16; Ell. N. Amer. Fung. 557
a and b; *Seym. & Earle, Econ. Fung. 300a, 300b, 309, 325;
Klotzsch Herb. Myc. 1745 sub Erystbe communis (in Herb. Mus.
Florence) ; *Ell. & Everh. Fung. Columb. 311, 418, 504 ; *Krieg,
Fung. Saxon. 577, 578, 722, 723; *Wartm. & Wint. Schweiz.
Krypt. 725 ; *Erikss. Fung. par. scand. 290.

Perithecia usually smaller, sometimes only 50 ug in diameter ;
wall usually harder and more brittle, cells larger, irregularly
shaped, averaging 25 » wide, but varying from 20-30 p, rarely
40 » wide; appendages usually short, pale brown, tortuous and
interwoven, but sometimes long, nearly straight, and dark brown ;
spores 20-25 X 12-15 p.

Hosts. —Adenocaulon bicolor, Adenostyles albida, Ajuga ciliata,
Arctium majus, Arnica cordifolia, A. montana, Astragalus alpinus,
Bartsia Odontites, Bidens cernua, B. chrysanthemoides, B. connata,
B. frondosa, B. tripartita, Calamintha Chinensis, Calendula arvensis,
C. officinalis, Carpesium abrotanoides, Cnicus Weyrichi, var. Gray-
anum, Collomia linearts (151), Coreopsis aristosa, C. aurea (265),
C. tripteris, Crepis paludosa, C. runcinata, Dimorphotheca fluvialis,
Doronicum Austriacum, D. grandiflorum (294), Draba alpina, var.
glacialis, D. hirta, D. incana, Erechtites pracalta, Erigeron acris,
E. annuus, E. Canadensis, Euphrasia officinalis, Fatoua pilosa, var.
subcordata, Fragaria glauca (151), Gerardia grandiflora, G.
quercifolia, Gaillardia aristata, Helianthemum vulgare, Hieracium
sp., Hydrophyllum Virginicum, Impatiens noli-tangere, I. textori,
Inula dysenterica, Lactuca brevirostris, L. Floridana (97), L. Rad-
diana, L. Sibirica, Leontodon autumnalis, Lophanthus anisatus,
Melampyrum nemorosum, M. pratense, M. sylvaticum, Microseris
aphantocarpha, Pedicularis cheilanthifolia, P. Groenlandica, P.
lanceolata, P. pycnantha, P. resupinata, Phlox dwaricata (60),
Physalis Alkekengi, Plantago lanceolata, P. media, Prenanthes alba

SPHAEROTHECA 53

(97), P. altissima (60), P. purpurea, Prunella vulgaris, Sanvitalia
procumbens, Saxifraga rotundifolia, Scabiosa arvensis, Scrophularia
canina, Senecio Cacatiastrum, S. cordatus, S. fluviatilis, S. Fuchsü,
S. lugens, S. nemorensis, S. Sarracenicus, S. subalpinus, S. trian-
gularis, Siegesbeckia orientalis, Taraxacum officinale, Tellima
grandiflora, Thalictrum alpinum, Troximon glaucum, T. officinalis
(151), Verbena sp., Vernoma Noveboracensis (363), Veronica longi-
folia, V. spartia, V. spicata, V. Virginica, Viola cucullata (36 3)
Xanthium Canadense, X. Italicum, X. macrocarpum, X. spinosum,
X. strumarium.

Distribution. —EvroPeE : Britain, France, Belgium, Nether-
lands, Switzerland, Italy, Germany, Austria-Hungary, Roumania,
Denmark, Norway, Sweden, Finland, Russia.

Asta: Turkestan, Siberia (Minussinsk), Japan.

NoRTH AMERICA: United States—Maine, Massachusetts,
New York, Pennsylvania, Maryland, New Jersey, West Virginia,
(249), South Carolina, Ohio, Michigan, Indiana, Illinois, Alabama,
Wisconsin, Missouri, Iowa, Minnesota, South Dakota (151),
Montana, Wyoming, Colorado, California, Washington ; Canada,
New Brunswick, Ontario.

Hosts recorded for the aggregate “S. Castagnei Lév. ” Arabis
alpina (176), Aster Bellidiastrum ( 3), Caltha palustris (2 30),
Carlina vulgaris (261) (290), Cichorium Intybus (214), Crepis tec-
torum (319), Cucumis sativus (22) (132) (133) (345) (377), Cu-
curbita (35) (132) (133) (176) (209) (214) (271), C. maxima (68),
C. Pepo (22) (377) (390), Dipsacus fullonum (272), Epilobium
angustifolium (391), E. tetragonum (319), Eupatorium cannabinum
(209) (214), Geranium dissectum (176), G. molle (205*), Heuchera
parvifolia (6), Hieracium sabaudum (214) Impatiens Balsimina
(43), Zapsana communis (272) (319), Linaria vulgaris (107), Ly-
cium ovatum (319), Pedicularis foliosa (290), Pentstemon barbatus
(107), Plantago major (390 and 391), Platanus occidentalis (22)
(296), Potentilla approximata (235), P. Pennsy vanica (347), Poter-
ium Sanguisorba (214) (229) (230), Rhinanthus angustifolius (319),
R. minor (3), Saxifraga punctata (311), Scabiosa integrifolia (214)
Scorzonera sp. (349), S. radians (235), Senecio Jacobaea ( zro) 5.
lyratifolius (3), S. spathulaefolius (1 76), S. sylvaticus (22) (344)
(345), S. vulgaris (230) (263) (353), Spiraea filipendula (58),

54 A MONOGRAPH OF THE ERYSIPHACEAE

Thalietrum simplex (348), Thelesperma filifolium (288), Trifolium
(204) (209), Urtica (177), Vitis vinifera (22).

. Burrill (61) was the first to point out that the old “ Sphacro-
' was an aggregate species, comprising two
sets of forms on different host plants which show constant differ-
ences in the size of the cells of the outer perithetical wall. Rely-
ing on this character, and on others mentioned below, Burrill
divided **.S. Castagnei Lév." into two species. S. humuli and
S. Castagnei. These two plants I have described above under
the names of S. kumuli and its variety fuliginea, as from the
study of a large amount of material I feel convinced that the two
are not specifically distinct.

To separate the two forms as species, Burrill relied on differ-
ences in these characters: the size of the cells of the outer peri-
thecial wall, the nature of the appendages, and the size of the
spores. S. Aumuli is stated to have cells usually less than 15 #
wide, appendages slender, 3 or more times as long as the diameter
of the perithecium, usually colored throughout when mature,
mostly free from the mycelium, and spores averaging 20 u long ;
S. Castagnei, cells 20-30 » wide, appendages long, stout, usually
colored throughout, but sometimes colorless, flexuous, somewhat
uneven in width, more or less interwoven with the mycelium, and
spores small, about 15 yw long.

The difference in the average size of the cells of the outer
wall of the perithecium, here pointed out, is certainly found, but,
at the same time, is not quite so sharply defined. In S. humuli
I have found the cells to vary from 10-20 p in width, occasionally
a single cell may measure 25-28 y, but the average width may be
stated as about 15 x; in the var. fuliginea the cells are much more
irregular in shape and measure, from 20-30 wide, occasionally
reaching to 40 » (it may be noted that the larger size and the
irregularity in shape of each cell is often seen to be caused by the
absence of a wall, which is sometimes clearly indicated) across
the middle. Occasionally, the cells in the var. fuliginea are not
wider than 20-25 y, and very rarely, indeed, as, e. g., in the speci-
men in Sacc. Myc. Ven. 1376, we find here and there a few cells
as narrow as 15 p—in fact, in this example, the cells have a
range of 15-25, or rarely 30 4 in width. On the other hand, in

theca Castagnei Lev.'

SPHAEROTHECA 55

a few forms of S. humuli, e g., specimens on Geum album, the
cells here and there become largely and slightly irregular in shape,
and I have found contiguous cells to measure 10 » and 28 nu wide,
although in the specimen in question the cells averaged under
20 p. Nevertheless, on the whole, with the few and rare excep-
tions noted above, the difference in the size of the cells is constant
and strongly marked, so that there is usually no difficulty in re-
ferring at once any specimen, by means of this character, to either
S. humuli or its var. fuliginea. The difference can be well seen
by comparing together the two commonest examples of these
plants, viz, S. kumuli on the hop, with S. humuli, var. fuliginea on
the dandelion.

I do not find the other separative characters put forward by
Burrill to hold good. Identically formed appendages are found
in certain examples of the two plants, and we can only say that as
a rule S. kumuli has longer, straighter, darker colored appendages,
while in the var. fuliginea they are, as a rule, shorter, paler, and
more tortuous. But to this rule there are certainly numerous
exceptions, and we find forms of S. humut, e. g., on Geum album,
Rubus, Gilia linearis, Geranium, etc., which have appendages iden-
tical in all respects with those usually characteristic of the var.
fuliginea, from which these examples can be separated only by
the small size of the cells of the perithecium. Similarly, certain
forms of the var. fuliginea, e. g., those on Microseris tenella, Senecio
lugens, etc., have long, deeply colored appendages, very closely
approaching those of typical S. kumuli.

The size of the ripe spores in the two plants is difficult to ascer-
tain, as the spores are formed very tardily, and in many of the
most interesting specimens it is frequently the case that no ripe
spores are to be found. As far as I have been able to observe, how-
ever, the difference in size given by Burrill does not appear to be
constant ; certainly the spores of the var. fuliginea often much
exceed ihe length given by this author, viz, 15 #; in the speci-
men in Syd. Myc. March. 297 (on Veronica long ifolia) they fre-
quently measure 25 o long.

There remains, therefore, only the difference in the size of the
perithecium, and this, while affording a fairly reliable character,
cannot, I think, be considered as one of more than varietal impor-
tance.

56 A MONOGRAPH OF THE ERYSIPHACEAE

A few words of explanation are necessary in connection with
the names here adopted for the two plants. Erysiphe humuli DC.
(1815), being the oldest name of either of the two, must stand as
the specific name of the plant here considered the type and called
S. humuli (DC.) Burrill. The other plant has, as already men-
tioned, been called S. Castagnei Lév. by Burrill, but this name
cannot be retained, and the oldest name Alphitomorpha fuliginea
Schlecht. (1819) must be adopted in its place. It is true that in
Schlechtendal’s description the large cells of the perithecium,
which form the essential character of the variety, are not mentioned,
so that the identity is established solely by means of the host-
plant (Veronica) given. As, however, we know that on this host
it is exclusively the large-celled form which occurs we can safely
adopt the name fulginea—just as has been already done in fact,
in the similar case of “ Erysiphe humuli” on the hop.

A form of S. kumuli which occurs on Pyrus Aria has been
described as a distinct species by de Thuemen under the name of
S. Niesslii. The separative characters relied upon were the smaller
perithecium and ascus, and especially the scattered habit ot the
plant. In examining a large series of S. humuli, however, it is
seen that the characters given cannot be considered distinctive of
the form on Pyrus Aria alone as we find examples on many other
hosts, e. g., on Potentilla, in which exactly the same habit is found.
In specimens on Potentilla, just as in “ S. Niesslii” on Pyrus Aria,
the appendages of the perithecium tend to become obsolete, per-
haps owing to the densely tomentose surface of the host-leaf in
both cases. The perithecia of “S. Wiess/ii” that I have examined
average 60 p in diameter (de Thuemen stated the average to be 86
nl, This is rather below the usual size for S. humuli, but perithecia
ofthe same size do occur on Potentilla and other hosts, with asci o,
as small a size as that given for “ S. JVzess/i" It may be noted too,
that in S. kumuli var. Juliginea perithecia with a diameter of only
50 # occur. On the whole, **.S. Niesslii” cannot be regarded as
anything more than a small form of S. Juli. :

E. epilobii is identical with certain forms of S. humuli. No
sufficient distinguishing characters have been given in any diagnosis
of this form, and it is evident that, as a general rule, specimens
have been referred to “ S. epilobii” merely from their occurrence
on species of Epilobium.

SPHAEROTHECA 57

Erysiphe erodii was the name given by Durieu and Montagne
in 1846-9, to a fungus occurring on Erodium moschatum at Oran,
Algeria. In their account of the plant, the authors described the
perithecium as containing many asci. In 1851 Léveillé identified
“E, erodii” with Sphaerotheca Castagnei. The correctness of this
identification has since been questioned by Montagne and also by
Saccardo (“Asci plures, ergo non Sphaerotheca”). An examina-
tion of the original Algerian specimens, however, confirms Léveillé's
determination, and shows the fungus to agree in all characters
with S. kumuli.

Professor Penzig kindly sent me for examination the type
specimen of S. fugax Penz. and Sacc. on Geranium sylvaticum.
The fungus shows these characters: perithecia 80-98 yin diameter ;
cells 15-20 wide, appendages long, up to 7 times the diameter
of the perithecium, colored pale brown for most of their length,
ascus 80-95x65-75 u, spores 20-22xX13-15 4. I cannot, in
fact, find that the plant differs in any way from S. humuli, which
occurs frequently on species of Geranium.

S. drabae Juel is certainly to be referred to S. mmu? var.
fuliginea, and the same is the case with. the S. Castagnet, var.
submutica of the same author. I am indebted to Professor Juel.
for specimens (now in the Kew Herbarium) of both these forms.
In the original diagnosis, S. drabae (on Draba hirta) is described
as having no appendages, and in a later description, where the
plant is recorded as occurring on Draba incana, Astragalus alpinus,
and Thalictrum alpinum Juel (186) remarks “ Rostrup hat einen
Zweifel aber den Wert dieser art ausgesprochen (Bidr. Kundsk.
Norges Sopart II. Christiania Vid.-Selsk. Forhandl., 1891) und
vermutet dass dieselbe von SpA. Castagnei nicht verschieden sei.
Bei Sph. drabae sind die Perithecien nur am Grunde durch einige
Hyphen mit dem Mycel verbunden, aber entbehren gänzlich der
Anhangsel.’’ In the numerous specimens of S. drabae sent to
me, however, I find, as a rule, a few short, pale brown, tortuous
appendages on the perithecium, and rarely the appendages are
even numerous. In the characters of the appendages, and in the
large perithecial cells, the specimens agree perfectly with S. humaulı
var. fuliginea. “S. Castagnei var. submutica" is the ordinary
form of the var. fuliginea on species of Melampyrnm.

58 A MoNOGRAPH OF THE ERYSIPHACEAE

A species of Sphaerotheca was published as S. pruinosa by
Cooke and Peck, in 1872, with the following diagnosis: “ Am-
phigenous. Mycelium effused, arachnoid, subpersistent. Con-
ceptacles minute, globose, scattered. Appendages few, inter-
woven, colorless.—On both surfaces of leaves of Rhus glabra,
Albany, New York. Habit and character of mycelium very dis-
tinct from S. pannosa. The colorless appendages will not permit
of its being confounded with S. Castagnei. Sporidia .0007-.0008
in. x .0004 in." Examination of the type specimens on Rhus glabra,
and of others on R. copallina, shows the fungus to possess these
characters : mycelium persistent, thin, and effused, perithecia
more or less scattered, 70-105 tin diameter, cells small, 8-15 u
wide ; appendages rather few, variable in length, sometimes, 6 times
the diameter of the perithecium, usually shorter, more or less
flexuous or angularly curved, usually more or less refractive and
shining white throughout, with the lumen obliterated, sometimes
brownish at base, very rarely pale brown nearly to the apex ; ascus
elliptic-oblong to subglobose, 70-90 4x 50-65 p, spores 8, 22-25
X 12-15 p.

As Cooke remarks, the habit and mycelial characters separate
the plant from S. pannosa, and the affinity is certainly wholly with
S. humuli, to which species, indeed, I have felt obliged, for the
reasons given below, to unite this form on Rhus. When investi-
gating the so-called **.S. pannosa” of many American mycologists
I was at once struck by the resemblance of some specimens of
this fungus on Rose-leaves to “ S. pruinosa.” In the first speci-
men examined, “on cult. roses, Madison, Wis., 1880 (Henry) "
(in the Herbarium of the Missouri Botanic Garden), the re-
semblance was so close that there could be no doubt that
the fungus on Rhus and this on Rosa belonged to the same spe-
cies. At that time I thought it might be possible, relying on the
white shining appendages to keep the plant distinct from S. humuli.
Since then, however, I have seen more material of this fungus on
American roses. For this I am indebted chiefly to Professor
Seymour and Professor Clinton, and the specimens sent (now in the
Kew Herbarium) show clearly that although this fungus on Rosa
has in many examples, quite colorless appendages like those of
“ S. pruinosa,” in others it may show distinctly colored appendages,

SPHAEROTHECA 59

and become indistinguishable from certain forms of S. humuli.
Evidence on another side also points to “ S. pruinosa” being only
a form of S. humuli. The form of S. humuli on Geranium sylva-
ticum published by Penzig and Saccardo as “ S. fugax" is de-
scribed as having appendages “‘hyalinae vel basi dilute fuligineae,"
and it was probably on account of this character that the authors
considered their plant as showing affinity with S. pruinosa. Al-
though in the type-specimen of “ S. fugax” the perithecia I exam-
ined showed more or less colored appendages, other examples
that I have seen of S. kumuli on species of Geranium have
had appendages colorless and shining in the upper half quite
agreeing in all respects with certain specimens on Kosa from
America.

It may be objected that as S. kumuli already contains so many
forms which differ in slight characters (e. g., the scattered or clus-
tered habit, a persistent or evanescent mycelium, long or very
short or even rudimentary appendages) it is inadvisable to include
under the name a form with shining white appendages. But if we
were to separate by means of this character, the plant on Rhus as
even a variety of S. kumuli, we should have to recognize, it seems
to me, very arbitrary and unnatural limits. In the first place,
with regard to the specimens on A/us, the occasional occurrence
of color in the appendages would have to be overlooked ; certain,
if not all, specimens on American roses (referred to above)
would have to be included in the variety, although forms on
species of Geranium would be found to completely connect them to
the type. It seems more natural, I think, to regard “ S. pruinosa”’
as only a form of S. kumuli. We may perhaps regard this white
appendaged plant on Rhus together with certain specimens on
Rosa, as a marked form developing into a new species, but at the
present time too closely connected by intermediates to be separ-
ated systematically. :

Halsted (156) records the occurrence of S. pruinosa on Phy-
toptus distortions on the inflorescence of Rhus glabra.

S. calendulae (Malb. & Roumeg.), on Calendula arvensis is S.
humuli, var. fuliginea ; the asci contain eight spores not six as de-
scribed. Fuckel records a fungus, observed only in the conidial
stage on Rubus Idaeus, under the name of Erysiphe ? rubi (Symb.

60 A MONOGRAPH OF THE ERYSIPHACEAE

Myc. 86, Wint. in Rabenh. Krypt. Fl. Deutschl. 17: 34. Itis prob-
able that this fungus is S. kwmuli, as this species occurs on sev-
eral American species of Rubus. The record of “ S. Castagnei”
on the vine probably rests merely on the occurrence of “ Oidium
Tuckeri" on the plant, as the latter was supposed by Fuckel
and others, to be a conidial form of “ S. Castagnet.”

S. humuli, when it occurs on hops, is well-known as “ hop
mildew," a disease which causes serious injury in hop-gardens.
On the leaves, the fungus does not occasion much damage, prob-
ably only slightly weakening the vitality of the host-plant, but
when it occurs on the cones it materially injures their quality, and
in severe attacks causes them to completely shrivel up. The
“hop mildew,” although recorded on cultivated hops on the Con-
tinent in many places, does not apparently cause so much damage
there as in England, where it is one of the most dreaded diseases
ofthe hop-grower. In the United States, also, although Burrill
(60, p. 6) says that S. kumuli “is a very destructive parasite, es-
pecially on cultivated hops"' the disease would appear, judging
from the absence of any reports (which have been so much made
by American mycologists on other plant-diseases) to be less prev-
alent or less severe than in English hop-gardens. As in the vine
powdery mildew, sulphur has been found to be an efficacious
remedy. The best results have followed from the use of flowers
of sulphur applied during sunshine. For full details of the prepar-
ation and application of the sulphur reference may be made to the
papers of Whitehead (392, 393) on the subject.

I cannot confirm the statement made in the Journal of the
Board of Agriculture for 1897 (181) that in hop-cones infected by
S. humuli the mycelial hyphae penetrate into the epidermal cells
of the bracts, as in material examined I have found within these
cells only the usual haustoria.

Whitehead (393, p. 247) recommends as a preventive method
against the hop-mildew the removal of all other plants which are
the hosts of the fungus from the hop-gardens, and mentions espe-
cially Zaraxacum, Senecio vulgaris and other Composites, and
Plantago. These host-plants of the old aggregate species “S.
Castagnei” all belong, however, to the form now separated as S.
humuli, var. fuliginea, while the hop-mildew is caused by the type

SPHAEROTHECA 61

S. humuli. The weeds that should be destroyed in English hop-
gardens are those which are known to be the hosts of S. Aumulı,
viz: Agrimonia Eupatoria, Alchemilla arvensis, Dipsacus sylvestris,
species of EZpilobium, Geranium, and Potentilla, and Spiraea
Ulmaria.

We are, however, at present, quite ignorant as to how far any
form of a mildew is capable of spreading from one host to another.
There is also the question—a most important one for systematists—
of the influence of the host-plant upon its parasite. The experi-
mental work necessary to answer these two questions is almost
entirely wanting. Magnus (227, p. 68), however, records the
following extremely interesting facts: “Ueber die Frage, ob die
parasitischen Erysipheen von einer Nahrpflanzenart leicht auf eine
Art iibergehen, sind mir keine Versuche bekannt. Ich selbst habe
einen einzigen hierhingehörigen Versuch mit Erfolg aufgestellt.
Es war mir auffallend dass Sphaerotheca Castagnei Lév. auf zwei
so verschiedenen Wirthspflanzen wie Humulus Lupulus and Tar-
axacum officinale auftreten sollte, zwei Wirthspflanzen, die ebenso
verschieden sind nach ihrer systematischen Verwandlschaft, wie
nach der physikalischen Beschaffenheit der Oberfläche ihres Laubes,
wie nach ihrer chemischen Beschaffenheit. Ich nahm Anfang Juli
1896 Blätter von Humulus Lupulus, die mit dem Oidium befallen
waren, und legte sie auf die Blätter eines pilzfreien Zaraxacum.
Am 27 Juli zeigten sich auf den Blättern des Taraxacum zahlreiche
scharf umschriebene Rasen des Oidium, and zwar nur auf den
Blättern des Taraxacum, die ich mit den Mehlthau tragenden
Hopfenblättern belegt hatte." Later, Magnus (2 30), noticing that
the two forms on Humulus and Taraxacum had been considered
as distinct species by Burrill, thus commented on his experiment :
“Nur möchte ich bemerken, dass ich mit Erfolg das Ordium von
Humulus Lupulus auf Taraxacum officinale geimpft habe. Dies
braucht nicht zu widersprechen der Auschauung, dass meistens auf
Compositen und auf Humulus Lupulus verschiedene Sphaerotheca-
Arten auftren, da recht gut so wohl auf dem Hopfen (auf dem ich
selbst Sphaerotheca humult (DC.) und Phyllactinia suffulta (Rebent.)
Sacc. bemerkt habe und auf dem Burrill (N. Amer. Pyren.) noch
Erysiphe cichoracearum DC. angiebt), als auch auf Zaraxacum
officinale zwei nahe verwandte Sphaerothecen gedeihen könnten.”

62 A MoNoGRAPH OF THE ERYSIPHACEAE

Magnus’ experiment is valuable in showing that the conidia of
S. humuli will germinate and produce a conidia-bearing mycelium
when shown ona house plant upon which (it is almost safe to
say) the ascigerous stage never occurs in nature. Unfortunately,
the experiment was not continued long enough to ascertain
whether perithecia would be produced. It is possible that the
fungus would not have been capable of producing these on the
unusual host-plant. This supposition would explain the fact of
S. humuli never having been recorded on Taraxacum, although in
nature its conidia may frequently germinate upon this extremely
common plant. On the other hand, it is possible that the conidia
of S. kumuli might have ultimately produced upon the Taraxacum
the large-celled perithecia which we at present consider distinctive
of the var. fuliginea (which is very common on 7: araracum) ` in
other words, it is possible that the difference in size of the cells
of the perithecial wall is due to the effect of certain different
host-plants on the same species of a parasitic fungus. We know
that in some forms of certain species of the Erysiphaceae, char-
acters to which even specific value has been given are directly
correlated with the occurrence of the fungus on a certain host-
plant—'* Mierosphaera pulchra” on Cornus alternifolia affords a
good instance. In this plant which is now allowed by all mycol-
ogists to be only a form of M. alni, a characteristic and more
elaborate branching of the apex of the appendages is connected
with the occurrence on Cornus ; in the case of S. humuli a similar
correlation may exist between the size of the cells, of the perithe-
cium and the host-plant.

S. humuli, in addition to causing the hop-disease, sometimes
seriously attacks cultivated strawberries. In America the disease
is known as the “ strawberry mildew,” and is stated (8) to attack
the fruit (both ripe and unripe) and fruit-stalks, as well as the
leaves of strawberries. The fungicide recommended is a mixture
composed of a quarter of an ounce of sulphide of potassium in a .
gallon of water; or, according to Humphrey (169), a preparation
made as follows : one ounce of carbonate of copper, mixed with
five ounces of carbonate of ammonia, and dissolved in a quart of
hot water ; when dissolved, sixteen gallons of water are-added.

In the Journal of the Board of Agriculture for 1898 (183) a

SPHAEROTHECA 63

disease is described which seriously affected some English straw-
berries during that year. Its attacks are described as follows:
“ This disease makes its appearance in May, in the form of white
spots upon the leaves. These gradually spread and cover the leaf
surfaces and extend to the fruit, covering it with white filaments,
which may easily be mistaken for common mould. * * Itismost
rapid and destructive in its action as the fruit approaches ripeness.
As in the case of the allied hop-mildew, which “runs” with
great rapidity in the hop-cones as they approach maturity, the
full virulence of the strawberry mildew is concentrated upon the
ripening fruit, so that the latter is spoiled before it is fit to pick."
The fungus causing this disease is here identified as S. phaerotheca
pannosa, but it is most probable that S. kumuli was really the
species that occurred. The description given of the fungus is
rather unsatisfactory (e. g., the perithecia are stated to contain
several asci); the figures of the perithecium, however—one of
which shows a perithecium in section with a single ascus—repre-
sent S. kumuli fairly well. It is recommended that imperfect
strawberry plants should be sprayed either with “a weak Bor-
deaux mixture, composed of 4 Ibs. of sulphate of copper and 3
lbs. of lime to 50 gallons of water, or with a composition of 2 Ibs.
of sulphide of potassium (liver of sulphur) to 50 gallons of water.”

S. humuli illustrates in a striking manner the impossibility of
placing any systematic value on the position or the scattered or
clustered habit of the perithecia. On Pyrus Aria, Potentilla argentea,
etc., the perithecia are uniformly and distantly scattered over the
lower surface of the leaf; on perhaps the majority of the host-
plants they are more or less gregarious, often on both sides of the
leaf, but frequently only on the upper surface, or commonly they
occur on the stem; on Gilia linearis, etc., the perithecia are closely
crowded into dense patches on different parts of the plant, while
on Neillia opulifolia, and in a few other cases, they are so densely
caespitose that they more or less encrust in places considerable
portions of the stem, petiole, etc.

Professor Selby has sent me a plant (now in the Kew Her-
barium) on Shepherdia Canadensis from Michigan, U. S. A., under
the MSS. name of Sphaerotheca shepherdiae. The distinctive char-
acters were considered to be the crowded habit of the small peri-

64 A MONOGRAPH OF THE ERYSIPHACEAE

thecia which here and there form black masses on the stem, and
the rudimentary appendages. After a careful examination of the
specimens sent I am quite unable to separate the fungus from S.
humuli, and feel convinced that it is only one of the many forms
of this species, and that the slight characteristics which it presents
(which are not, however, confined to the fungus on Shepherdia) may
be regarded as probably due in this case, to the position of the
fungus among the densely arranged peltate scales of the stem of
the host-plant. Griffiths (151) records S. kumuli, var. fuliginea
on Shepherdia argentea and S. Canadensis, and Burrill (60) the
same on S. argentea; probably in both cases the fungus is the
one above referred to S. kumuli.

Except in America, S. Aumuli has not hitherto been distin-
guished from the var. fuliginea, and the European host-plants, as
far as I have been able to see specimens of the fungus on them,
are here for the first time separated under the two forms. The
fungus recorded on host-plants which I have not seen I have been
obliged to leave under the aggregate species, “ S. Castagnei Lev."
Many of these hosts, e. g., species of Epilobium, Potentilla, etc., might
probably be safely considered those of S. kumuli ; others, e. g.,
species of Senecio, Impatiens, Balsamina, etc., as belonging to
the var. fuliginea.

Although so many authors have referred the fungus on Cz-
curbita and Cucumis to “ S. Castagnei,’ it seems very probable
that a mistake has been made in the identification, and that the
fungus in question is an Zrysiphe. In the first place, although
one finds in herbaria very numerous examples of a fungus in the
conidial (Oidium) stage on leaves of Cucurbita and Cucumis referred
to S. Castagnei, in my experience no specimens in the perithecial
stage are to be found in herbaria on these hosts. It is evident,
therefore, that for some reason it has been the practice among
mycologists to name any Oidium on Cucurbita and Cucumis, S.
Castagnei Lev. There can be no doubt also that this fungus on
cucurbitaceous plants is extremely slow in producing perithecia,
and the only example I have seen in this condition was gathered
in the late summer at Reigate, England, in 1898. This, as already
mentioned, proved to be Erysiphe cichoracearum.

The practice of referring a fungus in its Odium stage to a

SPHAEROTHECA 65

certain species of the Erysiphaceae has led, I feel convinced, to
very numerous mistakes, and has made any compilation of a host-
index from published records alone utterly misleading.

Further, not only are wrong host-plants for a certain species
thus given, but as a natural consequence our knowledge of the geo-
graphical distribution of the species in question becomes erroneous.
For instance, Winter (111) records the occurrence of “ Sphaero-
theca Castagnei” “ in foliis Cucurbitacearum from the island of St.
Thomas, Africa, an occurrence extremely interesting not only
geographically, but also climatically, as the island is on the
equator. In the present confusion it is impossible to say whether
the fungus was really “ S. Castagnei’’ in a perithecial stage, or,
whether, as is more probable, it was not merely an Oidium which
had been referred to S. Castagnei in accordance with the usual
custom.

The fungus recorded as “ S. Castaguei" on apples proves to
be Podosphaera leucotricha ; the records of the present species on
Trifolium and Urtica probably belong to Exysiphe polygont.

2. S. PANNOSA (Wallr.) Lev.

Alphitomorpha pannosa Wallr. Berl. Ges. Nat. Freund. Verh.
1:43. 1819; Wallr. Fl. Crypt. Germ. 2:760. 18

Eurotium Rosarum Grev. Scot. Crypt. Fl. 3: Ps eg f.
1823, and 6: Synops. 7, 1826.

Erysibe pannosa Schlecht. Fl. Berol. 2: 170. 1824: LES
Willd. Sp. Pl. 6: 104. 1824; Rabenh. Deutschl. Crypt. Fl. 1
230. 1844.

Erysiphe pannosa Fr. Syst. Myc. 3: 236. 1829; Duby, Bot.
Gall. 2: 869. 1830 ; Berk. in Sm. Engl. Fl. 5: 325. 1836; Tul.
Sel. Fung. Carp. 1 : 208. pl. 4. f. 1-3. 1861.

Sphaerotheca pannosa Lév. Ann. Sci. Nat. HL I5:158. M. 6.
f.8. 1851; Cooke, Mier, Fung. 218. pl. I1. f. 217,218. 1865;
Cooke, Handb. Brit. Fung. 2: 645. 1871; Sacc. Syll. Fung. 1:
3. 1882; Wint. Rabenh. Krypt. Fl. Deutschl. 1°: 26. 1884; Karst.
Act. Soc. Faun. Fl. Fenn. 2: 94. 1885; Burr. & Earle, Bull. Ill.
State Lab. Nat. Hist. 2: 398 (partim). 1887; Cooke, Handb.
Austral. Fung. 313. p/. 25. f. 239. 1892; Burr.; Ell. and Everh.
N. Amer. Pyren. 6 ( partim). 1892; Schroet.; Cohn's Krypt. Fl.

66 A MONOGRAPH OF THE ERYSIPHACEAE

Schles. 3: 230. 1893; Jacz. Bull. l'Herb. Boiss. 4:726. 1896;
Oudem. Rév. Champ. Pays-Bas. 2: 82. 1897.

Podosphaera pannosa de Bary, Beitr. Morph. Phys. Pilz. 1:
§ xiii., 48. 1870.

Abigo pannosa (Wallr.) Kuntze, Revis. Gen. Plant. 3°: 442.
1892.

Exsicc.: Desmaz. Pl. Cr. Fr. ed. 1: ser. 1 : 404; Baxt. Stirp.
Crypt. Oxon. fasc. 2: 92; Lib. Pl. Crypt. Ard. fasc. 1: 80:
Cooke, Fung. Brit. Exsicc. 9o, ed. sec. 589; Rab. Fung. Eur.
2214; Rehm. Ascom. 796 ; Fckl. Fung. Rhen. 72$; Berk. Brit.
Fung. 96; * Rab. Herb. Myc. ed. 2: 459; Wahrlich. Parasit.
Pilze. 31 (in Herb. Hort. Imp. Petropol.) ; * Syd. Myc. March.
4514; *Erikss. Fung. par. scand. 33; *Seym. & Earle, Econ.
Fung. 131b.

Mycelium persistent, forming on the stem, calyx, petiole, and
rarely on the midrib at the back of the leaf, dense satiny patches,
at first shining white, but often becoming gray, dingy buff, or rarely
pale brown, composed of densely interwoven special hyphae,
which are about 6 » wide, sparingly branched, somewhat rigid, re-
fractive and thick-walled, with the lumen becoming obliterated ;

Distribution. — EvRoPE. — Britain, France, Portugal (395),
Spain (—), Belgium (14) (209), Netherlands ( 1), Switzerland
(176), Italy, Germany, Austria-Hungary (20) (43) (95), Den-
mark, Norway, Sweden, Russia.

Asıa —Cyprus, Transcaucasia (338), India (85).

AUSTRALIA.— Queensland (89), Victoria, New South Wales
and Queensland (225).

NORTH AMERICA.— United States : Tennessee, Illinois (probably
in many other states, but has been generally confused with .S.
humuli ).

SPHAEROTHECA 67

[W. Inpies.—Jamaica (76). ]

[Sours America.—Quito, Ecuador (275). ]

The present species is sharply marked off from all the species
of the Erysiphaceae by its pannose satiny patches of persistent
mycelium, in which the perithecia are usually completely immersed.
Under the microscope these patches are seen to be composed of
special hyphal branches from the ordinary . vegetative mycelium,
about 6 u wide, somewhat rigid, more or less straight, sparingly
branched, with numerous free, somewhat tapering ends, The
hyphae are thick-walled, becoming more or less solid at maturity
through the obliteration of the lumen, and are shining white and
refractive, so that each hypha has somewhat the appearance of a
solid glass rod. Among these densely interwoven hyphae the
perithecia are produced. These are interesting in being some-
times distinctly pear-shaped ; the appendages are short, or quite
rudimentary.

Although S. pannosa in its Oidium-stage (O. leucoconium
Desmaz.) often covers the upper surface of rose-leaves, I have not
been able to find, in the considerable amount of material exam-
ined, any perithecia formed here. It is only rarely, indeed, that
perithecia are formed on the leaves at all (the stem usually being
chosen), and then it is always in the characteristic pannose patches
on the petiole or at the back of the midrib, and not scattered over
the surface.

It has frequently been asserted that the mycelium of S. pan-
nosa is perennial, and reappears in successive years on the same
shoots of infected roses, and it has been supposed by many authors
that the mycelium is capable of entering at times into the tissues
of the host-plant, although no direct evidence exists, apparently,
to support this view (cf. Winter (394, P- 26) and Schroeter (319,
p. 230) where the author remarks: Dieser Pilz kann auf den
befallenen Stöcken überwintern und wird selbst durch Pfropfreiser
übertragen”). In the examination of shoots of rose-bushes cov-
ered with patches of S. pannosa in different stages of development,
I have found only the usual haustoria in the epidermal cells, and
no signs of an internal mycelium. It was noticeable, too, in the
specimens examined that the fresh centers of disease which ap-
peared in the spring did not occur at the places (marked by con-

68 A MONOGRAPH OF THE ERYSIPHACEAE

spicuous scars or the nearly black and decaying remains of the
old persistent mycelium) where the fungus grew in the previous
year. Eriksson remarks on the subject (rro)z-* Die bei
diesem Pilze vorhandenen Perithecien scheinen ubrigens nicht fiir
sich allein das Fortleben des Mehlthaues in dem Grade wie er dem
Gartner jetzt bekannt ist, genugend zu erklaren, besonders wenn
man an die in den- Gewächshäusern so verheerende, so weil
bekannt nie perithecienführende Form der Krankheit denkt. Ihre
dortige Lebenskräftigkeit muss unzweifelhaft auf andere Ueber-
winterungsweisen, z. B. auf ein unter günstigen Umständen in die
peripherischen Gewebe der Nährpflanze eindringendes und da
fortlebendes Mycelium, auf ein saprophytisches, hefepilzänhliches
Entwicklungsstadium des Pilzes im Sinne Brefeld’s oder dgl. zu-
rückgeführt werden. Mikroskopische Beweise fiir die eine oder
andere Annahme sind jedoch noch nich gebracht worden.”

In Europe S. pannosa is not uncommon, indeed in its Oidium-
stage it is very frequent, on wild and cultivated roses, although
perithecia are produced less commonly. From Asia (Cyprus)
Professor Gennardius has sent me specimens on Rosa damascena,
which are identical with European examples. Cooke (85) states
that in India roses suffer the attacks of S. pannosa in the same
way as they do in Europe; and in the same author's work on
Australian fungi (89) S. pannosa is recorded (an unsatisfactory
figure is given) “ on rose-leaves ” from Queensland.

How far these records and those of S. pannosa from the West
Indies and South America rest on the occurrence of an Oidium-
stage on rose-leaves, identified as that of S. pannosa merely from
growing on this host-plant, it is impossible to say. The prevalent
practice of naming species of the Erysiphaceae in the conidial stage
cannot be too strongly condemned, for it is notas a rule from reli-
ance on morphological characters that such naming takes place,
but simply from the assumption that the species of fungus which
occurs on a certain host-plant in one part of the world will be the
same as that growing on the same host in other parts.

The danger of making such assumption is well seen in connec-
tion with a mildew common on American roses, which on account
of its occurrence on roses has been wrongly referred to the present
species. To any one familiar with the appearance of S. pannosa

SPHAEROTHECA 69

in Europe, with its distinct habit, the remark of Burrill (60, p. 6),
that the affinity between S. pannosa and S. humuli is quite as
close as between S. humuli and its variety fuliginea appears
strange, and still more so does Earle’s note on the specimen of
"bh pannosa”’ in Seymour and Earle's Economic Fungi, no. 131a,
that “this form is so like S. humuli (DC.) Burrill that it causes
doubt in my mind as to whether the two can be kept distinct."
On examining American material it became at once clear that
what has passed in the United States for S. pannosa is for the most
part a quite distinct species, viz, S. kumuli. This form of A
humuli on rose-leaves is a very interesting one, and when, as is
frequently the case, the appendages are colorless and shining,
is identical with “ S. pruinosa” on Rhus. At other times
however, the appendages are more or less colored, and there seems
little doubt that Earle's opinion that the form is not distinct from
S. humuli is correct.

It is a most interesting fact that in America S. kumuli should
have attacked roses, while in Europe, where S. kumuli is equally
common, only S. pannosa is known on this host. The case, how-
ever, is quite analogous with that of another species of the Zry-
siphaceae, viz, Microsphaera aimi which is very common in the
United States on Syringa vulgaris, yet in Europe, where both the
fungus and the host-plant occur frequently, there is no record of
the lilac being attacked by M. almi.

I have seen only two specimens of true S. pannosa from America
—one in Seymour and Earle’s Economic Fungi, no. 131b, on
Rosa sp. from Tennessee ; the other sent to me by Professor Keck
Clinton “on Rosa sp. ; stems ; Illinois.” Owing to the confusion
that has existed between S. kumuli and S. pannosa, mentioned
above, it is impossible at present to give the distribution of the
latter species in America.

S. pannosa is the “ rose-mildew," so well known to rose-grow-
ers, and if unchecked is a dangerous disease, quickly spreading
from bush to bush in its conidial (Oidium) stage. As in the case
of the vine-mildew, however, a fungicide which is usually effica-
cious is found in flowers of sulphur, or potassium sulphide (half
an ounce of sulphide of potassium dissolved in a gallon of water).
For roses grown under glass, Maynard (243) reports that a sure

70 A MONOGRAPH OF THE ERYSIPHACEAE

and safe remedy is found in the use of evaporated sulphur. The
author gives these directions: “In the use of this remedy a
small kerosene stove with a thin iron kettle was used, and the
sulphur kept boiling two or three hours thrice each week, when the
house was kept closed. Care must be taken that only enough
heat is used to boil the sulphur, and that it is not set on fire.”
Guercio and Baroni (101*) recommend as a fungicide the follow-
ing mixture : carbonate or crystals of commercial soda, kg. 1.5,
Norwegian vegetable tar, kg. 0.5; water, liters 100. The soda
and tar must be boiled together in about two liters of water, and the
rest of the water then added at the ordinary temperature. Spray-
ing with this mixture is stated to have been completely successful
in checking the disease in cases where the use of sulphur and sul-
phate of copper had little effect.

The records of “ S. pannosa” on gooseberry in America be-
long to S. mors-uvae ; those on Rubus, and probably also on rasp-
berries, to S. kumult. The record of S. pannosa on Spiraea Ul-
maria (391) probably refers to S. kumuli. Worthington G. Smith
(330) states that S. pannosa “ sometimes grows on Spiraea and
the hop, but hop-mildew is of course a different fungus.” Here
again, notwithstanding the concluding remark, S. humuli has prob-
ably been confounded with the present species.

3. S. MORS-UVAE (Schwein.) Berk. and Curt.

Erysiphe mors-uvae Schwein. Syn. Fung. Am. Bor. 270.
1834.

Sphaerotheca mors-uvae (Schwein.) Berk. and Curt. Grevillea,
4: 158. 1876; Sac Syll Fung, I: 5. 1882; Burr. and
Earle, Bull. Ill. State Lab. Nat. Hist. 2: 399. 1887; Burr. ;
Ell. and Everh. N. Amer. Pyren., 7. 1892.

Albigo mors-uvae (Schwein.) Kuntze, Revis. Gen. Plant. 3? :
442. 1892.

Exsicc.: Rab.-Wint. Fung. Eur. 3239; Ell. and Everh. N.
Amer. Fung. 1536 ; Roumeg. Fung. Gall. Exsicc. 3882.

Amphigenous ; mycelium persistent, when mature forming
dense pannose patches, composed of sparingly branched, more or
less flexuous, brown hyphae, which are about 5 p wide, at first
pale brown and plainly septate, becoming dark brown and thick-

SPHAEROTHECA 71

walled so that the septa and lumen become obliterated ; perithecia
gregarious, more or less immersed in the persistent mycelium,
sub-globose or sometimes slightly irregular in shape, 76-110 nm
diameter, cells large, at first well-defined, then becoming obscure,
variable in size, 10-25 f£ wide, usually 15-20 #; appendages
usually few (or even obsolete), pale brown, short, and tortuous,
rarely more numerous, and longer, up to 5 times the diameter of
the perithecium ; ascus elliptic-oblong to sub-globose, 70-92,
rarely 92-110 x 50-62 u; spores 20-25 X 12-15 fi.

Hosts. —On the berries, and occasionally stems and leaves of
wild and cultivated species of Ribes; A. cereum (6), R. Cynosbati,
R. divaricatum, var. irriguum, R. floridanum, R. gracile (—), R
Grossularia, R. Hudsonianum, R. lacustre, R. Missouriense, R. pros-
tratum, R. rotundifolium, R. rubrum.

Distribution—NortuH AMERICA: United States—Maine (163),
New York, Pennsylvania! New Jersey (53), Ohio ! Michigan, Illi-
nois ! Mississippi (361), Wisconsin (97), Missouri! Iowa! Dakota!
Nebraska! Montana! Wyoming! Colorado (157) (170).

Botrytis euphorbiae Cast. Supp. Cat. Pl. Mars. 81. 1851.

Erysiphe (Sphaerotheca) tomentosa Otth, Mitth. natur. Gesell.
Bern. 1865: 168. 1866.

Sphaerotheca tomentosa Otth ; Jacz. Bull. l Herb. Boiss. 4: 723.
1896; Sacc. Hedwigia, 35: Repert. XXIII. (1896) ; Dom. Sacc.
Att. Soc. Ven.-Treub. Sci. nat, (17) A. 5. f. 1. 1896; Sacc.
Syll. Fung. 14: 462. 1899. ;

Erysiphe gigantasca Sorok. & Thuem ; de Thuem. Myc. univ.
no. 645. 1877; Sacc. Syll. Fung. 1: 18. 1882.

Sphaerotheca gigantasca (Sorok. & Thuem.) Bàuml. in Rehm,
Ascom, fasc. XXI. n. 1049. 1891; Hedwigia, 30: 261. 1891;

Schroet.; Cohn's Krypt. Fl. Schles. 3: 232. 1893.
| Albigo tomentosa (Otth) Kuntze, Revis. Gen. Plant. 3°: 442.
1892.

Exsıcc.: de Thuem. Myc. univ. 645* ; Syd. Myc. March. 3462
(sub S. Castagnei). ;

Hosts.—Euphorbia dulcis, E. helioscopia, E. palustris (20*), E.
Peplus, E. platyphyllos, E. stricta, E. virgata (164*).

Distribution —EuRoPE: France, Switzerland, Germany, Aus-
tria-Hungary, Denmark, Russia. mus

S. mors-uvae is distinct from S. pannosa (with which it has

12 A MONOGRAPH OF THE ERYSIPHACEAE

been occasionally confused in America) in the dark-brown color
of the persistent mycelium, the usually smaller ascus, etc.

In 1865 Otth (262) described a species of Sphaerotheca on the
leaves and stems of Euphorbia dulcis in Switzerland, under the
name of “ Erysiphe (Sphaerotheca) tomentosa,’ with the following
description; “ Epiphylla caulinaque. Subiculum maculaeformi-
effusum, tomentosum, rufum, in ambitu albidum, e floccis longis-
simis, rufis, eseptatis, contextum. Conceptacula subiculo inspersa,
subimmersa vel plus minus emersa. Appendiculae a subiculi
floccis minime distinctae. Sporangium unicum, sporis octonis
foetum.” In 1877 the same plant was published as a new species
under the name of Erysiphe gigantasca by Sorokin and de Thuemen
(in de Thuemen’s Myc. Univ., no. 6 54) on the stems of Euphorbia
platyphyllos and E. dulcis in Russia. In 1881 Baumler (20*)
recognizing that Sorokin and Thuemen's plant was a Sphacrotheca,
called it S. gigantasca. Jaczewski in 1896 revived the forgotten
name of Otth’s S. tomentosa.

An earlier name, however, for this plant on Euphorbia is that
of Botrytris euphorbiae, published by Castagne (67) in 1851 fora
fungus on Euphorbia Peplus. The identity is pointed out by M.
Hariot in a note attached to a specimen of “ Botrytris euphorbiae
Cast’’ in the herbarium of the Paris museum, in which it is stated
that in this author's opinion the fungus is “ Erysiphe gigantasca
Sorok. & Thuem." The specimen is very young, and the mycelium
has not yet attained its characteristic brown color, but I was able
to find a few perithecia, showing a single ascus, and there can be
no doubt that the Botrytis euphorbiae of Castagne is the same
fungus as Otth's Sphaerotheca tomentosa.

Although the specific validity of this European fungus on
Euphorbia has not hitherto been questioned, it appears to me that
it cannot be separated from S. mors-uvae. After much comparison
I have failed to find sufficient characters to separate this European
plant on Euphorbia from the American one on Ribes. Although
as a rule the fungus on Euphorbia affects the stems rather than the
leaves, there are specimens in Otth's herbarium, noted as “forma
epiphylla," in which it forms irregular pannose or felted patches
on the leaves, exactly resembling those of S. mors-uvae on the
fruit of American gooseberries. The dark brown hyphae of the

SPHAEROTHECA 13

persistent mycelium in the two forms (on Euphorbia and Ribes) are
morphologically the same ; the only difference I have been able to
detect is that in the form on Zuphorbia the hyphae are perhaps
slightly more flexuous, and the perithecia are sometimes more
irregularly shaped, with a slightly larger (especially longer) ascus ;
but these differences are not, I believe, constant, and at any rate are
not more marked than those often found in the forms of one spe-
cies on different host plants. On the other hand there is so close
a resemblance in the habit and general morphological characters
of the two forms that I feel compelled to consider them as belong-
ing to one species. It would be extremely interesting if experi-
mental work could be carried out to test the correctness of this
view that the fungus on American gooseberries and on European
spurges belongs to the same species. The plant on Euphorbia is
apparently not common in Europe, but where it does occur it
should be seen if the conidia are capable of infecting gooseberries ;
in America attempts should be made to infect species of Euphorbia
with the conidia of .S. mors-uvae on Rides.

I have, in two instances, seen perithecia containing three asci
in American specimens of S. mors-uvae; the asci were much
smaller than usual (about 60x 35 4) and ovate-oblong in shape.

The record by Berkeley (35) of the occurrence of the present
species on “ grapes ” is due to some error, as in the specimen (now
in the Kew Herbarium) to which reference is made, the fungus is
growing on the leaves and the berry of some species of Aides.

In America S. mors-uvae is common on wild and cultivated
species of Rides, and is well known as a widely-spread disease
under the name of the '*'gooseberry-mildew." As the specific
name denotes, the fungus is especially harmful in attacking and
destroying the fruit, covering the berries with its persistent felted
dark-brown mycelium. It is not, however, confined to the fruit,
but often forms large confluent patches on the stems and leaves.

As a fungicide, Goff (147) recommends potassium sulphide.
The mixture used was one-half or one-fourth of an ounce of the
sulphide to a gallon of water, and was applied ‘‘as soon as the
leaves had begun to expand (May 3), and the application was re-
peated after every hard rain until June 24, nine sprayings having
been made in all. The new growth, as well as the crop of fruit,

14 A MONOGRAPH OF THE ERYSIPHACEAE

was very perceptibly greater on the treated plants." In a series
of experiments, on a large scale, carried on by Close (72) the
same fungicide was found the most effective. The potassium
sulphide solution here used was of the strength of one oz. to two
gallons of water. Spraying should be begun very early, just as the
buds are breaking, and continued at intervals of about ten days.
It was found that English vari2ties and their seedlings were, as a
rule, more subject to attack than the American varieties.

The gooseberry disease caused by S. mors-uvae is confined to
North America; the disease, called in Europe the “ gooseberry
mildew,” is due to the attacks of Mierosphaera grossulariae and is
not so dangerous, as it attacks only the leaves of gooseberry
bushes.

4. S. LANESTRIS Harkn.

S. Janestris Harkn. Bull. Calif. Acad. Sci. 1: 40. 1886;
Sacc: Syll. Fung. Addit. ad Vols. I-IV: 1. 1886; and 9: 364.
1891; Burr.; Ell. and Everh. N. Amer. Pyren. 9. 1892.

Albigo lanestris (Harkn.) O. K. Revis Gen. Plant. 3°: 442.
1892. :

Exsicc.: EU and Everh. N. Amer. Fung. sec. ser. 1537;
Rab.-Wint. Fung. Eur. 3240; *Seym. and Earle, Econ. Fung.
188.

Hypophyllous; mycelium persistent, when mature more or
less covering the under surface of the leaf, and composed of a
compact rather dense mass of much-branched, very tortuous, in-
terwoven, brown hyphae, which are thick-walled, or more or less
solid through the obliteration of the lumen ; perithecia gregarious,
imbedded in the persistent mycelium, subglobose, 80-120 p in
diameter, cells of outer wall obscure, irregularly shaped, 10-20 1
wide, inner wall becoming completely free from the outer,
formed of sub-hexagonal colorless cells with refractive walls, about
15 # wide ` appendages very short or obsolete, often entirely ab-
sent; ascus large, from elliptic- to broadly-oblong, more or less
distinctly stalked, 100-130 x 60-75 1; Aten 8, 24-30 x 18-
20 p.

Hosts.— Quercus agrifolia, Q. alba (12) (361), Q. macrocarpa,
Q. minor (361), Q. Prinus, Q. rubra (361).

Distribution —NORTH America: United States—Alabama,
Illinois! Mississippi (361), Missouri! Iowa (361), California!

SPHAEROTHECA 75

“Very conspicuous upon the growing shoots of Quercus agri-
folia—the Oidium as a white mealy stratum from Feb.-May, fol-
lowed by the ascophore on the leaves below. San Francisco”
(Harkness, 1. c.).

S. lanestris is a very conspicuous fungus in its dense scattered
or confluent patches, of a dull, dark-brown color when mature, on
the under side of oak leaves. In general habit it approaches,
through its persistent brown mycelium, S. mors-uvae, from which
it is, however, quite distinct in the more closely interwoven hyphae,
which are much more tortuous or even angularly bent, the sepa-
rating inner wall of the perithecium and the larger, usually slightly
stalked ascus.

The inner wall of the perithecium is formed of colorless angular
cells, about 15 x wide, with refractive walls, and, as the perithe-
cium approaches maturity, becomes completely separated from the
outer wall. When a nearly ripe perithecium is pressed open, the
ascus is forced out enveloped in the still unbroken inner wall.
Even with a perfectly ripe perithecium, when the free ascus es-
capes, the inner wall on gentle pressure usually follows the ascus
in the shape of a hollow globular body split towards the apex.
In this character S. /anestris recalls S. phytoptophila (see fig. 124).

Burrill (60) says, “ The perithecia * * * when carefully sepa-
rated appear to be absolutely without appendages.” Although
this is frequently the case, I have occasionally seen a few very
short, pale brown appendages at the base of the perithecium,
usually very much shorter than, and never exceeding, its diameter.

Harkness (158) described the Oidium form of S. lanestris as
follows “O. ventricosum; segments swelling in the center and
becoming barrel-shaped, 34-38 x 20-22 p, and filled with numer-
ous round or elliptic bodies, 5-6 x 2-4 #, which are freely dis-
charged from the ends, as the joints separate." It seems prob-
able that what was seen was merely the granular protoplasm
escaping from injured conidia.

Tracy and Galloway (363) remark of S. lanestris, “ the dense
mycelium completely covers the young leaves and. twigs, causing
the former to shrivel SES cease growing before they attain one-
fourth their usual size.”

76 A MONOGRAPH OF THE ERYSIPHACEAE

5. S. PHYTOPTOPHILA Kellerm. & Swingle. [Figs. 124-126 |

S. phytoptophila Kellerm. & Swingle, Journ. Myc. 4: 93.
1888; Kellerm. & Swingle, Ann. Rep. Kansas Exper. Sta.
I: 310: £N» 2.7: 9I. 1859. ace. Syll Pung. 92 : 36%
. 1891; Burr.; Ell. Everh. N. Amer. Pyren: 9. 1892.

Albigo phytoptophila (Kellerm. & Swingle) Kuntze, Revis. Gen.
Plant. 3°::442: 3.1892,

Exsıcc.: Kellerm. & Swingle, Kans. Fung. 23; Ell. & Everh.
N. Amer. Fung. sec. ser. 2336; Rab.-Wint.-Pazsch. Fung. Eur.
3954; *Seym. & Earle, Econ. Fung. 148.

Mycelium evanescent, or subpersistent ; perithecia more or less
gregarious, 60-78 # in diameter, cells small, about ou wide,
often indistinguishable, inner wall colorless or pale yellow (cells
10-15 4 wide, with refractive walls), usually separating entirely
from the outer wall ; appendages usually short, sometimes obso-
lete, more or less tortuous, pale or dark brown, sometimes as long
as 4 times the diameter of the perithecium, septate, occasionally
branched ; ascus elliptic-oblong to globose, and 60-75 x 42-50%;
spores 8.20—25 x 12-15 p.

Host.— Celtis occidentalis, on distortions caused by a species of
Phytoptus (gall-mite).

Distribution. —NORTH AMERICA : United States—Ohio, Indiana,
Illinois (60), Missouri, Iowa, Kansas.

Kellerman and Swingle (197) give the following description of
the present species: ‘‘ Mycelium very sparse; perithecia globular,
dark brown or black, obscurely reticulate, 60-80 micr., mostly
65-75 micr. in diam., appendages few, more or less evanescent,

Asci large, hyaline, broadly oval, containing 8 spores, which are
hyaline, oval, un in size, I3x 24-18 micr. Conidial stage:

mycelium more abundant, conidiophores hyaline, erect, total
height endlos conidia) 150-220 micr. by 9-13 micr. in diam
conidia oval, yaline, continuous, granular within, 15x 21-29,
mostly 15x 27 micr.

“The fungus is found associated with Phytoptus (an unde-
scribed species) on Hackberry (Celtis). The distortions caused
by the insect, or perhaps by both insect and fungus, consist of a
multitude of abnormal, more or less abortive branchlets that
form a compact knot, Y2—114 inches in diam.; a few of the
branchlets are prolonged a few inches and themselves bear smaller

SPHAEROTHECA TT

knots of similar structure. The abortive branchlets have exces-
sively numerous buds all infected by the insect, and covered by
the fungus. The conidial stage is found associated ‘with the
perithecia and sometimes even extending out on the twigs to
the under side of the leaves. The perithecia are found in the
spring but do not mature their spores till late fall or winter.” e

The more obscure cells of the outer wall of the perithecium,
the tendency of the inner wall to separate completely from the
outer, and the smaller average size of the perithecium and ascus
seem to be the only characters separating the present plant from
S. humuli, and are hardly important enough, by themselves, to
give specific rank. There is some evidence, however, which points
to the possibility of S. phytoptophila being distinct as a “ biological ”
species, and it is from these considerations, viz: that it is possible
that the present plant is a species closely allied morphologically to
S. humuli, but yet physiologically so dependent on its special host
as to be unable to grow elsewhere, that I have kept the two
distinct.

In the specimens I have seen of S. phytoptophila the inner wall
of the perithecium, composed of colorless, angular (often hexag-
onal) cells with refractive walls, shows a marked tendency to
separate completely from the outer wall. "When a ripe perithecium
is burst by pressure, causing the expulsion of the ascus, the inner
wall, often in the form of a hollow oval body split at one side, is
forced out at the same time (see Fig. 124). If the peritheeium
Which is opened is immature, the inner wall is frequently pressed
out unburst, completely enclosing the ascus. In .S. humuli, the
inner wall very rarely, if ever, presents this appearance, usually
closely adhering in fragments to the outer wall, or becoming more
or less absorbed. The small size of the ascus and perithecium
could probably be matched in certain forms of S. humuli.

The following observations of Halsted's (155) made on living
examples of S. phytoptophila are of great interest: “At this
season of the year (January) all traces of the mildew are absent
from anything except the infested or abnormal branches, and
upon these the’ perithecia are limited to the bud-scales, with a
particular preference shown to the lower portion of the scale.
Upon further study, the buds infested were found to be much

T8 A MONOGRAPH OF THE ERYSIPHACEAE

larger than those upon healthy branches and contained the peri-
thecia in all their tissues. For example, a bud well up from the
base of a twig might not show any signs of perithecia upon the
exterior, but when the large loose scales were removed the bases
of the inner ones would expose a dark covering consisting of the
mildew perithecia. Longitudinal sections through such buds
showed that the living tissue of an ordinary bud was absent, and
its space was occupied by an entangled mass of fungous fruit.
. . . As fungus parasites thrive upon compounds rich in albu-
minous substances, and as the Phytoptus induces a rapid and,
therefore, comparatively succulent growth upon a tree that nor-
mally has a dense wood, firm bark, and minute, closely protected
buds, it may, however, not be so strange that the Sphaerotheca
will flourish upon the distortions caused by the mite when it fails
to gain a foothold upon a healthy twig. . . . It was, moreover,
observed that in a cross-section of the stimulated branch there
was considerable starch scattered through the bark, while in the
healthy and mature twigs, where the buds were normal, smooth-
coated, and varnished, there was no starch outside the ring of
firm wood. This starch in the bark may be the secret of the suc-
cess of the Sphaerotheca upon the infested branches."

It is this apparently intimate association of S. phytoptophila
with the galls of the Ce/Zs that suggests the idea of the plant being
biologically distinct, and experiments bearing on this point, either
the sowing of the conidia of S. phytoptophila on host-plants of .S.
humuli or, conversely, attempts to infect the galls of the Celtis
with the conidia of S. /usiu/? are very desirable.

Kellerman and Swingle (198) mention that they were unable
to find any haustoria in living specimens, but consider that this
may have been due to the distorted nature of the epidermal cells.

Other cases of the occurrence of species of the Erysiphaceae
on galls caused by mites are known. The form of Micro-
sphaera alni described as “ M. erineophila” occurs on “ erineum "
galls on leaves of Fagus ferruginea; M. alni also occurs
under the same conditions on leaves of Cephalanthus occi-
dentalis. In both these cases, the presence of the galls seems
to cause the appendages of the fungus to become colored,
but there is no reason for considering the form a distinct species,

UNCINULA 79

nor to suppose that any intimate connection exists between the
fungus and the mite. I have once seen Uncinula circinata on
“erineum” galls on the leaves of Acer rubrum, and in this
instance the unusual habitat had no observable effect on the
fungus. Halstead (156) records the occurrence of “ Sphaerotheca
Pruinosa” on Phytoptus distortions on the inflorescence of Rhus
glabra. All these cases, however, differ from that of S.
Phytoptophila in one important respect, viz., that the species of
fungi recorded are found commonly on the same host-plant when
this is not attacked by mites, while S. phytoptophila (or any species
of Sphaerotheca) has not been recorded from Celtis unless this
host-plant has been altered by the attacks of the Fhytoptus.

Anderson and Kelsey (7) mention an association with mites of
“S. Castagnei" on Shepherdia argentea,and of S.mors-uvae on Ribes
rotundifolium, stating that **in both cases the distorted leaf-axils,
abnormally developed buds, and thickened brittle upper leaves
bore the perithecia of largest size and in greatest numbers." In-
stances are also given of mites occurring with “ S. Castagnei” on
Geranium incisum, with Erysiphe communis on Oxytropis Lamberti,
Astragalus triphyllus, and A. adsurgens, and with E cichora-
cearum on Chrysopsis villosa, Helianthus (several species), Cnicus
undulatus, Erigeron macranthus and Mertensia Sibirica. In all
these cases, however, we may note that the fungus in question
occurs commonly on unattached parts of the host-plant mentioned,
and in many cases it is very probable that the presence of the
mites is merely a coincidence.

UNCINULA Lév. Ann. Sci. Nat. III. 15: 151. 1851
Perithecia globose to globose-depressed ; asci several, 2-8
spored; appendages simple, or rarely (U. acerts) once or twice
dichotomously forked, uncinate at the apex, usually colorless,
rarely dark brown at base or throughout. Etym.: dim. of uncus.
Distribution.—Europe, Africa, Asia, Australia, North and
South America—18 species and 2 varieties.
The genus is distinguished at once by the uncinate apex of the
appendages.
Key to the Species of the Genus Uncinula
I. Appendages colored.
Appendages colorless.

A MONOGRAPH OF THE ERYSIPHACEAE

2. Appendages colored for half their length or mo 5. necator.
A tects ve colored only at base (up to the ER a: 16. australiana.
3. Asci 2-3-sp :
Asch 4-8- cni 6.
4. Asci more than 30, perithecia very large, 215-320 u in diameter. 12. polychaeta.
Asci 4-20, perithecia 85-165 u in diameter. 5.
5. nn es 9-25, perithecia average 95 x in diameter, asci 3-6. 4. clandestina.
Appendages Se, O, perithecia average 130 u, asci 8-20. 8. macrospora.
6. See all simple, i
Appendages some or all branched. 20.
7. Appendages e narrow, 3-4 4 wide, asci 4—7-spore 8.
Appendages stouter, er, or if narrow with asci 8- d IO.
8. Asci about 25, pre ane 150-200 u in diameter. 13. confusa.
— Asci 5-8, perithecia 86-122 u in deeg 9.
9. Appendages 50-160, 14-3/ diameter of we 7. parvula.
Appendages 24-46, 114-2 diameter of perithecia, e geniculate. II. geniculata.
10. Appendages stout, 7-8 u wide near the
Appendages narrower near the base. ae
11. Appendages very few, 6-12, enlarged upwards. 15. Delavayi.
Appendages crowded, 20-36, scarcely or not at all enlarged upwards.
18. Sengokut.
12. Rude meii abruptly flexuose or angularly bent. . 13.
Appendages straight. 14.
13. Appendages iint equalling eier of perithecium, flexuose above, not angularly
bent, spores usually 9. flexuosa.
Appendages en CH 115-2 diameter of paran more or less angularly
bent, spores 4-6, rarely 7. . salicis, var. Miyabei.
14. Appendages. p^ ck- Women er or rough at base. I
Appendages thin-walled throughou 17.
I5. Mycelium persistent, pui vows perithecia 156-268 < in diameter
: 2. aceris, var. Tu wlasnei.
Mycelium evanescent or subpersistent, perithecia 64-146 u in ee 16
16. Asci ovate or elliptic-oblong, 24-30 u wide, spores 16-20 x8-Iou. 3. _ prunastri
Asci broadly ovate to subglobose, 34-40 u wide, spores 20-25 X 10-13 u
10. Clintoni.
17. = 4-6- A 5 : iy xe
ci 7-8-s S |
18, Pech gam win diameter, appendages not exceeding en of peri

rcinata.
neg 76-138 u in diameter, "e I1/-24 times dis i ihe.
cium.

19.
. Perithecia 120-138 w in diameter, appendages 35-60, mone persistent, more
d.

or less densely compacte I4. australis.
Perithecia 76-105 u in —À appendages 10-28, mycelium evanescent,
17: “ea
Mycelium densely compacted, appendages mostly single. 2. aceris, var, Tulas
Mycelium not See compacted, appendages all or nearly all branched.

2. aceris.

UNCINULA 81

I. UncinuLA saticis (DC.) Winter. [Figs. 62, 63, 85]

Erysiphe salicis DC. Fl. Fr. 2: 273. 1805 ; Duby, Bot. Gall.
2:871. 1830; Tul. Sel. Fung. Carp. z : 198. pl. 2. f. r. 1861.

E. populi DC. Syn. Pl. Fl. Gall. 57. 1806; de Bary, Beitr,
Morph. Phys. Pilz. 1: $ xiii, 52. 1870.

E. varium Fr. Obs. Myc. (partim) 1: 206. 1815, and 2:
366. 1818.

Alphitomorpha adunca, var. populi Wallr. Berl. Ges. Nat.
Freund. Verh. 1: 37. 1819.

A. populi Wallr. Ann. Wett. Ges. 4: 236. 1819.

A. obtusata Schlecht. Berl. Ges. Nat. Freund. Verh. r: 50.
1819.

Erysibe populi DC. Gray Nat. Arr. Brit. Pl. 1: 589. 1821.

E. adunca var. populi Lk. ; Willd. Sp. Pl. 6: 111. 1824.

E. obtusata (salicis) Lk. ; Willd. Sp. Pl. 6: 117. ar 1824.

E. adunca Schlecht. Fl. Berol. 2: 169. 1824.

Erysiphe adunca Lk. ; Grev. Scot. Crypt. Fl. 5: A. 296. 1827;
and6: (Synops.) 9. 1828; Berk.; Sm. Engl. Fl. 5: AJ. 2. 327.
1836.

E. adunca, vars. populi et salicis Fr. Syst. Myc. 3: 245. 1829.

E. adunca, var. populi Duby, Bot. Gall. 2: 870. 1830.

E. capreae (DC. Herb.) ex Duby, Bot. Gall. 2: 871. 1830.

Alphitomorpha adunca, var. amentacearum Wallr. Fl. Crypt.
Genn Ju 1833

Erysibe adunca var. amentacearum Rabenh. Deutschl. Krypt.
FL 22 235, 1894:

Uncinula adunca Lev. Ann. Sci. Nat. III. 15: 151. X. 7.

f. 15.* 1851; Cooke, Mier, Fung. 219: a rr. f. 221-224.
1865; Cooke, Handb. Brit. Fung. 2: 646. f. 374. 1871; Peck,
Trans. Alb. Inst. 7: 214. f. 7-3. 1872; Karst. Myc. Fenn., 2:
196. 1873; Sacc. Syll. Fung. 1: 7. 1832.

U. luculenta. E. C. Howe, Journ. of Bot, II. 1: 170. 1872.

U. heliciformis E. C. Howe, Bull. Torr. Club, 5: 4. 1874;
Sacc. Syll. Fung. 9: 367. 1891.

U. salicis (DC.) Wint.; Rabenh. Krypt. Fl. Deutschl. 1?: 40.

* Excl. syn. Vader su ci depressa, var. artemisiae Wallr. and Zrysibe de-
pressa, var. artemisiae

82 A MONOGRAPH. OF THE ERYSIPHACEAE

1884; Karst. Act. Soc. Faun. Fl. Fenn. 2: 94. 1885; Burr.
and Earle, Bull. Ill. St. Lab. Nat. Hist. 2: 410. 1887

Schroet. ; Cohn's Crypt. Fl. Schles. 3::245: 1803; Jacz. Bull,
l Herb. Boiss. 4: 742 (syn. excl. partim). 1896; Oudem. Rev.
Champ. Pays-Bas. 87. 1897.

Erysiphe populi Patouill. Journ. de Bot. 2: 217 (cum icon.).
1888 ; Sacc. Syll. Fung. 9: 370. 189r.

Uncinula Columbiana Selby, Bull. Ohio Agric. Exper. Sta.
(Techn, Ser) 1: 201.9 E 1893; Sacc. Syll. Fung. zr:
252, . 1805.

U. salicis, var. epilobii Vestergr. Botan. Notiser, 2 56. 1897;
Sacc. Syll. Fung. 14: 462. 1899.

Exsicc: Bri. e Cav. Fung. par. 69, 171; Fckl. Fung. Rhen.
699, *700, 2236; Cooke, Fung. Brit. Exsicc. "DSL 2,597;
de Thüm. Fung. Austr. 130, 131, 132, 236, 655 ; de Thüm. Myc,
univ. 959; Desmaz. Pl. Cr. Fr. ed. I, Ser. I, 268, 2195, *ed. 2,
ser. I, 113, 1845; Rehm, Ascom. 549, 550; Rab. Fung. Eur.
560, 1045, 2316, 2317; Rab. Herb. Myc. ed. 2, 464, 465 ; Rab.-
Wint. Fung. Eur. 3046; Baxt. Stirp. Crypt. Oxon. fasc. 2, 29;
Karst. Fung. Fenn. 367; Sacc. Myc. Ven. 615, 890; Ellis, N.
Amer. Fung. 425; Roumeg. Fung. gall. exsicc. 970 ; Syd. Myc.
March. 836, 1657, 2329; Jack, Lein. and Stizenb. Krypt. Bad.
630; Westend. Herb. Crypt. Belg. 80; Ellis and Everh. Fung.
Columb. 109, *314; Ellis and Everh. N. Amer. Fung. 3007 ;
*Wartm. and Schenk, Schweiz. Krypt. 320; *Kneiff. and Hartm.
Pl. Crypt. Bad. 17; *Seym. and Earle, Econ. Fung. 198 ; *Hoppe,
Fung. Epiphyt. 5, 6, sub Sclerotium erysiphe Pers. ; Jacz. Kom.
Tranz. Fung. Ross. Exsicc. 28 (in Herb. Hort. Imp. Petrop.) ;
*Erikss. Fung. par. scand. 34; Schleich, Crypt. exsicc. 77 (in
Herb. DC.).

Amphigenous ; mycelium evanescent, or persistent and then
usually thin and effused, but sometimes densely compacted and
forming definite circumscribed patches ; perithecia densely gre-
garious or more or less scattered, globose-depressed or lenticular,
90-175 in diameter, averaging 135 p, cells 10-15 # wide; ap-
pendages usually numerous, often densely crowded and 100-1 50,
or more, sometimes fewer, rarely only 30-15, 34-214 times the
diameter of the perithecium, simple, aseptate, or occasionally 1-

UNCINULA ; 83

septate at the base, hyaline and thin-walled throughout, usually
gradually and slightly enlarged upwards, apex simply uncinate or
occasionally more or less helicoid; asci 8-14, rarely only 4—6,
elliptic-oblong or broadly ovate, usually stalked, 55-80 x 30-40 D
averaging 68 x 36 p; spores 4-6, 20-26 x 10-15 p.

Hosts —Populus alba, P. angustifolia (6), P. balsamifera and
var. candicans, P. ciliata, P. grandidentata, P. heterophylla, T
monilifera, P. nigra, P. pyramidalis, P. tremula, P. tremuloides, P.
trichocarpa, Salix alba, S. angustifolia (57), S. aurita, S. Capraea
and var. pendula, S. cinerea, S. cordata, S. daphnoides, S. discolor, S.
flavescens and var. Scouleriana, S. fragilis (22) (344), S. glauca (6),
S. humilis, S. incana (230), S. Zvida, S. longifolia (6), S. nigra
and var. fa/cata, S. nigricans, S. petiolaris, S. purpurea, S. pyrolae-
Jolia (347), SS. repens, S. sericea, S. Seringiana, S. triandra, S,
Urbaniana, S. viminalis [Betula alba (107) (176) (204) (214)
(307) (394), Buxus sempervirens (383)].

Distribution —Furore: Britain, France, Portugal, Belgium,
Netherlands (263), Germany, Switzerland, Italy, Austria-Hungary,
Denmark, Norway, Sweden, Finland, Russia.

Asta: Transcaucasia (338), Siberia (Minussinsk), India, China
(Yunnan), Japan.

NORTH America: United States—Maine, Vermont, Massa-
chusetts, New York, New Jersey (53), Carolina (90), Ohio, Mich-
igan, Indiana, Illinois, Mississippi (361), Wisconsin, Missouri,

owa, Minnesota, Kansas, Dakota, Montana, Wyoming, Wash-
ington, California. Canada—Ontario, Quebec.

The most widely distributed and the most variable species of
the genus, but, as a rule, easily recognized by the numerous simple
appendages slightly exceeding the diameter of the perithecium.
The appendages are usually slightly enlarged upwards (but not
sufficiently so as to make the apex club-shaped) and remain
hyaline and thin-walled throughout, not becoming thick-walled
or refractive towards the base, as is the case with several allied
species.

Although there can be no doubt that the two forms growing
respectively on poplars and willows constitute but a single species,
we usually find these two forms characterized as follows. The form
of U. salicts occurring on species of Salir has uniformly larger peri-

84. A MONOGRAPH OF THE ERYSIPHACEAE

thecia, the appendages in proportion to the diameter of the perithe-
cium are shorter, nearly always more or less crowded, and have a
small and closely uncinate apex ; the asci are usually 4-spored. In
the form of U. salicis occurring on species of Populus the perithecia
average smaller, the appendages are fewer—in rare cases as few
as 15—longer, more flaccid, with the apex frequently more loosely
uncinate, and the asci are more often 6-spored. So many exam-
ples, however, on both Salir and Populus show characters inter-
mediate in every respect—for instance, it is not at all uncommon
to find forms on Populus in which the appendages are very crowded
—that, as already mentioned, the two forms cannot be considered
specifically distinct. We may, however, perhaps regard them as
incipient species which are being evolved on different host-plants.

Léveillé (214), Winter (394), Jaczewski (176), Saccardo (307),
and other authors have recorded U. salicis as growing on Betula,
but I have not been able to find specimens on this host-plant in
any herbarium. It may be that perithecia (without appendages)
of Phyllactinia corylea—a species which occurs commonly on
Betula—have been mistaken for immature examples of the present
species, and the same suggestion may be made with regard to
Wallroth’s (383) record on U. salicis on Buxus sempervirens.

Léveillé (214, p. 151) recorded Artemisia vulgaris as a host-
plant for U. salicis, and (l.c., p. 152) gave “ Alphitomorpha depressa
var. B artemisiae Wallr.” as a synonym of the present species.
Léveillé remarked, “ J'ai recu beaucoup d'échantillons d'Erysiphés
sur l'Armoise sous le nom d' Erysiphe depressa, et pas un ne se
rapporte avec celui de Wallroth, que renferme l'herbier de M.
DeCandolle. C'est cette espèce que je réunis al’ Uneinula adunca
[U. salicis], parce qu'elle en présente tous les caractères ; l'autre
est un Erysiphé proprement dit" In Berkeley's herbarium, at
Kew, there is a specimen from Léveillé's herbarium, labelled in the
latter author's handwriting “ Uncinula aduca. — Alphitomorpha
depressa Wallr. 3. artemisiae. Specim. Wallrothii.”

On this specimen (on the leaf of Artemisia vulgaris) there are
two species, viz : Uncinula salicis and Erysiphe cichoriacearum. Of
the former species, I found only two perithecia. These were quite
loose and merely entangled in the hairs of the leaf, and I feel no
hesitation in regarding their presence as accidental. Wallroth’s

UNCINULA 85

Alphitomorpha depressa, var. artemisiae is certainly Zrysiphe
cichoracearum, as an examination of Wallroth’s type shows. Other
authors also (107) (204) have stated that Uncinula salicis occurs
on Artemisia, but it is very probable that the statement is often
copied from Léveillé. Paque (270) has lately (1885) recorded U.
salicis on this host, but the specimens kindly sent to me by this
author prove to be Erysiphe cichoriacearum.

The record by Cooke and Peck (91, p. 170) of the occurrence
of the present species on Aesculus is a mistake, and refers to
Uncinula flexuosa.

Uncinula luculenta E. C. Howe is one of the forms of U.
salicis on poplar, and has been correctly referred to this species
by American botanists.

U. heliciformis E. C. Howe (on Populus balsamifera in the
United States) cannot be separated from U. salicis, although it is
in certain respects a marked form. Howe (167) described the `
appendages as “spirally coiled above, colored at base," and on a
specimen (now in the Kew Herbarium) sent to Cooke, has
remarked, “possibly a variety which unites U. spiralis B. & C.
with U. ampelopsidis Peck." ‘An examination of this specimen
showed the perithecia to be 80-120 in diameter with 24-38 col-
orless aseptate appendages, about 134 times the diameter of the
perithecium. The apex of the appendages is, when mature, 2-3
times coiled in a helicoid manner (Fig. 85), and in this respect is
similar to that of U. necator (U. spiralis). In all other characters,
however, especially in the colorless aseptate appendages “ U.
heliciformis" shows no affinity whatever with this species. It is
certain, too, that a more or less helicoid apex to the appendages
must be regarded as a character of very little value, as it appears
occasionally in species which normally have a simply uncinate
apex, e.. g., U. macrospora, U. fraxini, etc. Among some speci-
mens of U. salicis sent to me by Professor Massalongo, from
Italy, an example occurs on Populus nigra in which many, though
not all, of the appendages have a distinctly helicoid apex. On
the whole, therefore, “ U. heliciformis’’ must be ranked as only an
interesting form of U. salicis.

Erysiphe populi Patouill. on Populus tremula from China
(Yunnan) is U. salicis, and was described from immature peri-

86 A MONOGRAPH, op THE | ERYSIPHACEAE

thecia before the appendages had. become uncinate (see figure in
Journ. de Bot. 2: 217. 1888). M. Patouillard kindly sent me
specimens (now in the Kew. Herbarium), on which. was noted
“ Erysiphe (Uncinula) populi Pat; diffère de U. adunca [ U.
salicis| par ses théques sub-6-spores.” Examination showed the.
asci to be 4-6-spored, . and inthis and all other characters M.
Patouillard's plant agrees perfectly with U. salicis. -

U. Columbiana Selby was published. as growing on Een
lateriflora at Columbus, Ohio. The author. remarked (324),
“ This species resembles U. circinata C. & P. in.-the form. of
perithecia,, but is distinguished from it by the more abundant my-
celium, by the broader asci, and the fewer and larger spores. ` Un-
like previously reported species of the genus its host is a herb and
one commonly affected by an Zrysiphe. ^ The material on hand is
mature though rather scanty.": Professor Selby very. kindly sent
me the type specimens for examination. I found the perithecia to
measure 100-150 4 in diameter, the appendages are.numerous,
hyaline and thin-walled throughout, simply uncinate, 1—1 17 times
the diameter of the perithecium ; the asch are about 60 x 35 0
5- or 6-spored, spores 20—22.x 10 p. In:all respects, therefore,
the specimen agrees well with U. salicis; U. circinata differs in the
larger perithecia, shorter appendages, larger asci, and 7—8 spores.
Professor Selby's material shows some perfectly ripe perithecia,
but is rather scanty, and I have not been able to satisfy myself
perfectly that the Uncznula was growing on the Scutellaria. There
is certainly a species of mildew growing on the Scutellaria leaves,
as is shown by the presence of some young perithecia on the my-
celium, but, as far as I have been able to see, these are too young
to show any appendages, and it is just possible that they do not
belong to the Uncinula, but to Erysiphe cichoracearum, which is
not uncommon in America on this Seuze//arza. -The Uncinula has
not been reported subsequently on Scutellaria, and considering
that there is a possibility that its presence on this plant was ac-
cidental, it will be wiser to wait for confirmation before recording
Scutellaria lateriflora as a host plant for Uncinula salicis. Perhaps
a parallel case to the above is afforded by the occurrence of U.
geniculata on Hydrophyllum, mentioned below or of U. salicis on
Artemisia (see above). By a curious mistake Saccardo gives, in

UNCINULA ns 87

his Host Index, “Uncinia Columbiana” . as..the host oke of
Selby’s species.

. U. salicis has been hitherto BEER from Asia only from: Si-
beria (Minussinsk). It appears, however, to be not uncommon in
Japan, whence Professor Miyabe has sent me specimens on. five
species. of. Salix and on three species of Populus; from China
(Yunnan) it.has been recorded, as mentioned above, under the
name of Arysiphe populi. The present species occurs also in: India,
but. has been recorded as Erysiphe Martii by Cooke, in Grevillea
(83)... The specimen, collected at Simla on. Populus: ciliata, is in
the Kew Herbarium ; it is somewhat immature, but shows some
fully ripe and deeg perithecia. `

Oestergren (372) has recently described a SE DES Urai
under the name of- Uneinula salicis (DC.) Wint. var. epilobii n. v.,
on which the following interesting observations Gen given in:
translation) are made :

"The host-plants which are given in. the terat for Un-
cinula salicis belong to the genera Salix, Populus and Betula ; it
was, therefore, quite surprising to find the above form, which very
closely agrees with U. salicis, on a host so widely different from
these genera as Epilobium angustifolium. U. salicis appears, how-
ever, to have been once before recorded on a herbaceous plant, as
Winter (Die Pilze Deutschl. ete., 2: 40) remarks that this species
“soll auch auf Artemisia vulgaris gefunden worden sein, doch
erscheint diese Angabe sehr unwahrscheinlich.”. As mentioned
above, the form found on Epi/obzum agrees in its chief characters
with U. salicis.. It appears worthy of note that the appendages
which are here so numerous at the base of the perithecium are
only of the same length as the perithecium, while in the type on
the contrary they attain to quite double this length, and it is
worthy of remark, also, that at the time of maturity of the fungus
the mycelium appears to have almost completely disappeared,
while in the type, on the other hand, it is generally persistent. I
have, however, found the same behavior with regard to the my-
celium in several examples of U. salicis in the botanical collections
of the Upsala Museum. As the biological adaptation of the Zry-
sipheae to different host-plants i is almost unknown, it may be best
to denote the morphological agreement of this form with U. salicis

88 A MonoGRAPH OF THE ERYSIPHACEAE

by placing it as a variety under this species, although it is, perhaps,
not improbable that it is, biologically, distinct from it. The most
obvious presumption would be that the perithecia of the Uncinula
in question had been transferred by the wind to the Epilobium from,
€. g., some Salix bushes growing in the neighborhood. Apart
from the fact that there were none of the usual host-plants of U.
salicis in the neighborhood one must quite reject this presump-
tion when one observes (under a slight microscopic magnification)
how firmly the perithecia of the var. epilobii are fixed to the sub-
stratum by means of the appendages radiating on all sides. More-
over, the infected shoots were densely covered along their entire
length with perithecia, whereas no signs of the fungus could be
found on herbaceous plants growing in the neighborhood."

I have not seen a specimen of this Uncinula on Epilobium, but
from the diagnosis and the author’s remarks there seems no reason
whatever for separating it from U. salicis. Certainly the charac-
ters chiefly relied upon, viz, the length of the appendages and
the evanescence of the mycelium, cannot be considered distinctive
of the “ var. epilobii” (cf. the diagnosis of U. salicis given at p.
82). The question whether any form on a certain host-plant is
biologically distinct can only be answered by experiment, for its
mere assumption would lead to the establishment of a new “ bio-
logical" variety or species at each occurrence of a species on a
new host-plant. Also, remembering the case of the accidental
occurrence of U. salicis on Artemisia (and perhaps also on Scutel-
laria) mentioned above, it will be best to wait until perithecia have
been seen growing on a mycelium on the Epilobium before record-
ing the latter as a host-plant for U. salicis, although in the present
case the crowded habit of the perithecia makes it seem probable
that the Eplobium was serving as a host-plant.

The fungus described as parasitic on perithecia of Uncinula
salicis by Cocconi (75*), under the name of Phoma uncinulac, is
probably Ampelomyces.

~ Var. Miyabei var. nov. [Figs. 73-78]

Amphigenous, or epiphyllous ; mycelium usually evanescent,
or (on the upper surface of the leaf ) subpersistent, thin and effused,
rarely forming definite spots; perithecia gregarious or more or

UNCINULA 89

less scattered, globose-depressed, 70-120 A in diam., aver. 95 y,
cells about 10 x wide; appendages 11-48 in number, usually from
20-30, 133 to twice the diameter of the perithecium, very rarely
only equalling the diameter, simple, smooth or often rough towards
the base, aseptate, thin-walled and hyaline above, often becoming
refractive at the base, 4-6 ^ wide, usually slightly enlarged up-
wards and about Gu wide, more or less abruptly flexuose or
angularly bent in the upper half, sometimes irreguiarly swollen or
sub-nodulose, apex simply uncinate, or frequently sub-helicoid ;
asci 4-7, broadly ovate to subglobose, with or without a short
stalk, 40-56 x 30-38 4 ; spores 4-6, or rarely 7, 19-21 x 10-12 jt.

Hosts — Alnus incana, A. maritima (A. Japonica).

Distribution. —Asıa: Japan (Sapporo, K. Miyabe, October,
1890, September, 1894, September and October, 1895, on Alnus
Japonica; G. Yamada, September, 1896, on A. incana).

The present plant shows some affinity with U. geniculata and
U. flexuosa in the usually flexuose or angularly bent appendages,
but in all other characters it is so closely allied to U. salicis that
it seems best to place it a variety under this species. In the notes
which Professor Miyabe sent with the specimens of Japanese Zry-
siphaceae, the present plant is thus referred to: “ Related to U.
salicis, but perithecia smaller (100 4). Appendages fewer in num-
ber (22-30), slightly flexuose and nodose, longer (180-200 /).”
In certain forms of U. salicis on poplar, however, we meet with
perithecia only 9o y in diameter, with only from 15-30 appendages,
which frequently reach to 2% times the diameter of the perithe-
cium. Asa rule, however, U. salicis can be at once distinguished
from the present variety by the larger size of the perithecia, which
average 135 4 in diameter (those of the variety averaging 95 ft),
and the more numerous appendages.

It is, however, by certain characters of the appendages that
the var. Miyabei is best distinguished. If several perithecia are
placed under the microscope, it will be seen that the appendages
of by far the greater number are abruptly flexuose or angularly
bent in the upper half, as shown in figs. 73, 74, 75» and in this
respect are somewhat similar to those of U. geniculata. Further,
the appendages of the var. Miyabei become, when mature, refrac-
tive and thick-walled at the base, whilst in the type, as far as I
have seen, they invariably remain thin-walled throughout.

90 A MONOGRAPH: OF, THE ERYSIPHACEAE

At first sight, the present variety appears to much resemble.
U, geniculata, but on closer comparison it is seen that in the latter
species the appendages are always — narrower, not enlarged
upwards and more delicate. ;

Rarely, the appendages. of, the present plant are more or less.
regularly flexuose and not angularly bent; there is then some
slight approach towards ©. flexuosa, which siden m the shorter
appendages, 8-spored asci, etc. Very rarely, and perhaps abnor-
mally, a single apperidage is found branched at the apex (figs. 76,
77) Wes | JM Ce

The only example sent on Alnus incana differs from those on
A. Japonica in the mycelium forming definite spots on the upper
surface of the leaf. The perithecia are seated on these, and as
a rule, although not invariably, are larger.

zU AcERIS (DC.) Sacc: [Fig. 87]

Mucor Erysiphe Linn. Sp. Pl. 2: 1186 (partim). 1753.

Erysiphe aceris DC. Syn. Pl Fl Gall. 57. 1806; Duby,
Bot. Gall. 2: 870. 1830; Tul Sel. Fung. Carp. r: 197. X. 2.
$%2,7...1801; de Duy, Bar. Morph. Phys. Pg 2: 5 xii,
$2. 1870. |

E. varium Fr. Obs. Myc. (partim) 1: 206. 1815; 2: 366.
1818. ! |

Alphitomorpha bicornis Wallr. Berl. Ges. Nat. Freund. Verh.
I: 38. 1819; Wallr. Ann. Wett. Ges. 4: 235. 1819; Wallr.
PI Crypt, Ger. 2: 755. 18511.

Erysibe aceris DC., Gray, Nat. Arr. Brit. Pl. 1: 589. 1821.

`E. bicornis (acerum) Lk. Wit. 5b I O: 412, 1824;
-Rabenh. Krypt. Fl. Deutschl. 1: 235. 1844.

Erysiphe bicornis Fr. Syst. Myc. 3: 244 (partim). 1829;
Berk.; Sm. Engl. Fl. 5: 327. 1836; Corda, Icon. Fung. 2
28 pl. 13.f. 100. 1838. |

Uncinula bicornis Lev. Ann. Sci. Nat. III. 15: 153. pl. 7. f.
17 (partim). 1851; Cooke, Mier, Fung. 219. fl. r1. f. 225-228.
1865 ; Cooke, Handb. Brit. Fung. 2: 647. 1871.

U. aceris (DC.) Sace Syll. Fung. 1: 8. 1882; Whit in
Rabenh. Krypt. Fl. Deutschl. 1°: 41. 1884; Schroet. in Cohn's
Crypt. Fl. Schles. 3: 246. 1893; Jacz. Bull. l'Herb. Boiss. 4:

ob UNGINULA uy a Ganti A 91

738 (excl. syn. U. Tulasnei Fckl.). 1896; Oudem. Rév. Champ.
Pays.-Bas. 2.: 88. 1897. . Pita i
Exsicc.:, Rab.-Wint. Fung. Eur. 2941 ; Brit. and Cav. Fung.
par. 70; Rehm. Ascom.. 77; Sacc: Myc, Ven. 146; de Thüm.
Fung. austr. 133, and Myc. Univ. 154; and (cum Phyllactinia
corylea),;1055 ` Bad Mygi March, ‚143, *658, *3674, :*4231;;
Kunze, Fung. ‚select..exsicc. 236, 575; Desmaz. Pl. Cr. Fr. ed. 1,
SEF st 207, 1 1125, %ed...2,.ser. 1,15 12;,.Mize,,.Fung. iBrit.;1975
and. *198 sub. Migrosphaera , Hedwigit; Westend. Herb. Crypt..
Belg. 550 ;..Cooke, ,Fung,. Brit. Exsice, 93, ed. 2, 282 ;. Jack,
Lein. and. Stizenb..: Krypt. Bad. 51; ,Ayres,. Myc... Brit. 28:
Roumeg. Fung. Gall, Exsicc.. 971; Fekl.. Fung. Rhen. 701;
Klotzsch, Herb, Myc. 179; *Rab, Fung. Eur. 559; *Wartm.,and
Schenk.: Schweiz. Krypt..212; *Kneiff. and Hartm; Pl. Crypt.
Bad. r4 ; Erb, Gritt: Ital. ser. 2, 818,.1364 (in. Herb. Mus. Flor-
ence). y, ; bru. Lb

Amphigenous ; mycelium evanescent, or. persistent as. a thin.
effused film-; perithecia scattered or subgregarious, hemispherical
or globose-depressed, large, 120-225 fin diameter, usually about
180 on, cells ill-defined; about 10 x wide; appendages numerous,
12-34, rarely equalling the diameter of the perithecium, smooth,
colorless, thick-walled to:the apex, usually a very few simple, the
rest bifid, with occasionally one or both of the branches: again.
forked, apex of the. simple appendages or of the branches unci-
nate; asci 4-12, usually 6-10, sub-pyriform or oblong, with. or
without a short stalk, 70-95 X 45-55 H: spores usually 8, rarely
6, 22-26 x 13-15 p.

Hosts — Acer campestre, A. monspessulanum, A. pictum, A. pla-
tanoides, A. pseudo-platanus, A. rubrum (394), A. spicatum, A.
tataricum [Phillyrea media (214)].

Distribution. — EvROPE: Britain, France, Belgium, Nether-
lands (263), Germany, Switzerland, Italy, Austria-Hungary,
Denmark, Sweden, Russia.

Asia: Transcaucasia (338), Japan.

U. aceris is recognized at once by its forked appendages (Fig.
87) which more or less cover the upper half of the perithecium,
forming a kind of crown (see Tulasne's beautiful figures, Sel.
Fung. Carp. 1: (4 2f 2-3) ^ — :

Nearly all authors have described the perithecia as becoming

92 A MONOGRAPH OF THE ERYSIPHACEAE

depressed, or pezizoid in age. This statement rests on a curious
misconception. On looking at a leaf on which there are mature
examples of U. aceris we nearly always find that some perithecia,
as seen from above, appear very concave, or even cup shaped ;
a closer examination, however, shows that these are perithecia
which have become turned over, so that the upper half, with the
appendages which it bears, is pressed to the surface of the leaf
The base of the perithecium, thus exposed, soon loses all traces
of mycelial hyphae, and becomes concave, simulating the truly
“pezizoid” perithecia of such species as Erysiphe taurica. `
Whether this turning over of the perithecium is natural, and
due to some growth of the mycelium or action of the appendages,
or whether it is accidental, I am not able to say. The appen-
dages, which through the turning over of the perithecium are
pressed against the leaf, sometimes seem to become slightly
attached to it, and it is noticeable that the apices of these
appendages show, under the microscope, signs of having become
slightly disorganized; they may possibly, therefore, adhere to the
leaf through some mucilaginous degeneration. Observations on
living plants are necessary before the question of how this curious
reversal (already in 1861 observed by Tulasne (370)) of the peri-
thecia takes place can be answered,

Acer campestre and A. pseudo-platanus are the usual host-
plants of the present species ; it is only very rarely indeed that U.
aceris occurs on A. platanoides, being usually replaced on this host
“by the var. Zu/aszei,* and it is not common on the other species
of Acer mentioned (A. monspessulanum, A. rubrum, etc.) The
Japanese examples occurred on A. pictum and A. Spicatum, and are
very interesting geographically.

As a rule, the simple appendages are very few in number, and
more or less completely hidden by the very numerous forked
ones; on Acer fartaricum, however, the simple appendages are
numerous, and this form certainly shows an approach, in this re-
spect, to the var. Twlasnei ; the mycelial characters, however, are
those of the type.

U. aceris is not known to occur in America; the only record

Eriksson, however, states that he has frequently observed both these plants grow-
ing together on Acer p/atanoides in nurseries at Stockholm.

UNCINULA 93

of its occurrence there, by Harkness and Moore (159) rests on an
error.

Eriksson states (119) that the present species causes much
damage to young trees of Acer in the nurseries at Stockholm, and
recommends as preventive measures the collection and burning of
the diseased leaves.

The conidial stage of the present species was described as
Oidium aceris Rabenh. Flora, 12: 207. 1854.

— var. Tulasnei (Fckl.) [Figs. 90-92]

Mucor Erysiphe Schrank, Prim. Fl. Salisb. 240 (partim). 1792.
Erysiphe bicornis Fr. Syst. Myc. 3: 244 (partim). 1829.
Erysibe aceris Wahl. Fl. Suec. 2: 1086. 1833.

Uneinula bicornis Lev. Ann. Sci. Nat. III. 15: 135 (partim).
1851.

U. Tulasnei Fckl. Fung. Rhen. ur. 1746. 1866 ; Fckl. Symb.
Myc. 81. 1869-70; Sacc. Syll. Fung. 1: 9. 1882; Wint. in
Rabenh. Krypt. Fl. Deutschl. 1°: 41. 1884.

Exsicc.: Fckl. Fung. Rhen. 1746 ; Syd. Myc. March., 2835,
* 4232, and 2764 sub U. bicornis; Rab. Fung. Eur. 1915; * de
Thuem. Myc. univ. 644, and Fung. austr. 1251 ; * Erikss. Fung.
par. scand. 35.

less, smooth, thick-walled, with the lumen nearly or wholly oblit-
erated in the lower part; asci 8—20, broadly ovate or elliptic-
oblong, 64-98 x 40-50 /, averaging 80 x 43 #; spores 8, rarely
6 or 7, 26-30 x 14-17 4t.

Hosts—Acer monspessulanum, A. platanoides, A. pseudo-Pla-
tanus (176) (210).

Distribution. —EvRoPE : France, Germany, Switzerland (176),
Austria-Hungary, Norway, Sweden, Russia.

U. aceris, var. Tulasnei is somewhat variable in the nature of
its appendages; sometimes these are all simple, when there is a

94 A MONOGRAPH OF THE ERYSIPHACEAE

certain resemblance to U: salicis, from which it is distinct in its
large size, usually 8-spored asci, and thick-walled appendages ;
sometimes many of the appendages are bifid, when an approach is
made towards the type. In U. aceris, however, although simple
appendages do occur, these are always very few in number, and
rarely, if ever, as numerous as in the var. 7u/asnei (see, however,
note.above). Moreover, the densely compacted persistent my-
celium is never found in U. aceris type.

Fuckel first separated the present plant as a distinct species
(U. Tulasnei), and gave in the diagnosis the character “ conidiis
concatenatis, perfecte globosis, 8 mik. diametr." Subsequent
authors have repeated the statement, and have relied on this
character as the chief one for separating the plant. Thus Saccardo
(307) says of U. Tulasnei, “ Praecipue habitu et conidiis globosis
dignoscenda species," and Winter (394, P. 42), “ Unterscheidet
sich von U. aceris hauptsächlich durch die kugeligen Conidien, die
bei jener, wie bei allen anderen Umeinula arten elliptisch sind."

Eriksson (119, ai 4: f. 70-12) figures these small globular
conidia, and contrasts them with the much larger conidia of U.
acerıs proper.

Examination of herbarium material makes me doubt whether
authors have been right in regarding these bodies as the conidia of `
the present plant. In certain specimens I have found, on the same
leaf, the two kinds of conidia represented in Figs. 90-92. Fig.
90 is evidently the form described by the above authors (cf. Eriks-
son’s figures) ; the conidiophores are very small, and with the small
more or less globose spores (about 8 win diameter) bear no re-
semblance to the Oxdium-form of other members of the Erysi-
phaceae. The other form (Fig. 91), present in about equal num-
bers agrees closely with the figures of the conidia and conidiophores
of U. aceris given by Eriksson (loc. cit., J. 7,8). His possible that
the small form is some species of Oospora associated accidentally
with the Uncinula.

The mycelial characters, which give the present plant so differ-
ent an appearance from the type, we know to be of very slight
systematic value (cf. remarks on “Erysiphe densa Berk), -and
other. characters seem hardly important enough to give a higher
than varietal rank under U. aceris.

UNCINULA 95

As to how far the present plant has been confused with U.
aceris, it is almost impossible to say. Fries (130, p. 244) (1829)
remarked under Zrysiphe bicornis, “ Species in Acere platanoide
fruticosa obvia eminus a reliquis dignoscitur maculis suis crustosis,
candidissimis, contiguis, determinatis, sericeis, semper epiphyllis.
Thallus tam insignis in nulla alia observatur." This evidently ap-
plies to the var. Tulàsnei. Léveillé, also (214), in 1851 included
the present plant under his Uncinula bicornis, as his description
and remarks on p. 154 show : there is also a specimen of the var.
‚Tulasnei in Berkeley's herbarium at Kew, named in Léveillé's
handwriting U. dicornis (see also. Tulasne (370, p. 197).

Acer platanoides is the usual host-plant for the present species,
and on this tree it appears to be not uncommon on the Continent.
It sometimes however occurs on A. monspessulanum (A. trilobatum),
and Jaczewski (176) and Le Breton and Niel (210) have recorded
it on A. pseudo-Platanus.

Eriksson (119, p. 7) records the present variety as often oc-
curring with U. aceris on the same plant of Acer platanoides, and
states that it causes great damage to this tree in the neighborhood
of Stockholm, not only to young plants in nurseries, but also to
large trees.

3. U. prunastri (DC.) Sacc. [Figs. 79, 80]

Erysiphe prunastri DC. Fl. Fr. 6: 108. 1815; Tul Sel
Fung. Carp. 1: 199. 1861; de Bary, Beitr. Morph. Phys. Pilz.
1: $ xui, $50. 1870.

Alphitomorpha adunca, var. prunastri Wallr. Berl. Ges. Nat.
Freund. Verh. 1: 37. 1819.

A. prunastri Wallr. Ann. Wett. Ges. 4: 237. 1819.

Erysibe adunca, var. prunastri Lk. Willd. Sp. Pl. 6: 112
1824.

Erysiphe adunca, var. prunastri Fr. Syst. Myc. 3: 245. 1829;
Duby, Bot. Gall. 2: 870. 1830.

Alphitomorpha adunca, var. rosacearum Wallr. Fl. Crypt. Germ.
2: 755 (partim). 1833.

Erysiphe adunca Fr. Kickx. Fl. Crypt. Erw. Louv., 139:
(partim). 1835.

Erysibe adunca, var. rosacearum Rabenh. Krypt. Fl. Deutschl.
I: 236 (syn. excl. partim). 1844.

96 A MONOGRAPH OF THE ERYSIPHACEAE

Uncinula Wallrothit Lév. Ann. Sci. Nat. III. 15:183 G49)
f. 16. 1851; Cooke, Handb. Brit. Fung. 2: 647. 1871.

U. prunastri (DC.) Sacc. Syll. Fung. 1: 7. 1882; Wint.;
Rabenh. Krypt. Fl. Deutschl 1?: 41. 1884; Schroet.; Cohn's
Krypt. Fl. Schles. 3: 245. 1893; Jacz. Bull. l'Herb. Boiss. 4:
742. 1896; Oudem. Rev. Champ. Pays.-Bas. 2: 87. 1897. `

Exsicc.: De Thüm. Myc. univ. 1450; Cooke, Fung. Brit.
Exsicc. 217 ; ed. sec. 281; Desmaz. Pl. Cr. Fr. ed. 1, ser. 1, 1306 ;
*ed. 2, ser. 1, 706; Roumeg. Fung. Gall. Exsicc. 3649; Roumeg.
Fung. Sel. Exsicc. 4928; Rab. Fung. Eur. 2133; Syd. Myc.
March. 835, *3823; Fckl. Fung. Rhen. 1747; *de Thüm. Fung.
austr. 463; *Sacc. Myc. Ven. 616 ; *Erb. Critt. Ital. ser. 2, 831
(cum Podosphaera oxyacanthae var. tridactyla); *Rab. Herb. myc.
ed. 2, 758; *Erikss. Fung. par. scand. 140; Westend. Herb.
Crypt. Belg. 969 (in Herb. Jard. bot. Bruxelles),

Amphigenous ; mycelium evanescent ; perithecia gregarious
or scattered, very variable in size, from 80-146 ^ in diameter,
usually about 105 p, globose-depressed, cells about IO ^ wide,
somewhat translucent ; appendages very variable in number, from
12-60, 1 44 to twice the diameter of the perithecium, rough (rarely
smooth) and thick-walled below, thin-walled above, colorless, asep-
tate, slightly enlarged upwards to a simply uncinate apex measur-
ing about (äu across; asci 7-18, ovate or elliptic-oblong, very
shortly stalked, 42-58 x 24-304; spores 5-7, 16-20 x 8-10 p.

Hosts —Prunus insititia, P. pumila, P. spinosa | Crataegus
(338)].

Distribution. —EUROPE : Britain, France, Belgium, Nether-
lands (263), Germany, Switzerland (176), Italy, Austria-H ungary,
Denmark, Norway, Sweden.

[Asıa: Transcaucasia (338)].

A very variable species in the size of the perithecium and
number of the appendages. When the latter are few, U. prunastri
recalls, by the rough base and enlarged apex of the appendages,
U. clandestina, but that species is distinct in the 2-3-spored asci;
when the appendages are numerous the present species approaches
U, salicis, to which, of the European members of the genus, it is
most allied, differing in the smaller perithecia and asci, the thick-
walled and nearly always rough base of the appendages, and the
smaller, usually 6-spores. The real affinity of U. prunastri is,
however, with U. Clinton (see remarks under that species).

UNCINULA 97

U. prunastri has hitherto been recorded ona single host-plant,
Prunus spinosa. I have, however, found examples contained in
the Herbarium of the Upsala Museum, on P. pumila, and have
also lately seen specimens growing on P. insititia, from France
(Bagnères de Bigorre, Pyrenees, 2000’ J. H. Burkill, Aug., 1899).

There is a specimen, in Cooke’s Herbarium, at Kew, labelled
“U. Wallrothit, f. Lonicerae Xylostei, M. Cerva. Belluno. 18 " in
Professor Saccardo's handwriting. On the honeysuckle leaves
there are certainly several perithecia of U. prunastri, but there is
no evidence to show that these grew there. The perithecia appear
to be all merely entangled in the leaf-hairs, and not fixed, and on
the slight traces of mycelium — on the leaf I could find no
signs of young perithecia.

Speschnew (338) records U. prunastri from Transcaucasia with
the following note. “ Le distingue du précédente [U. salicis] par
6 spores dans chaque ascus et a été trouvé sur une espece de
Crataegus, au parc de Tzinondaly, en septembre."

U. prunastri has been recorded from America, by E. C. Howe,
in Cooke and Peck's ** Erysiphei of the United States (91, p. 170),
by Bessey (40, p. 7), and in Farlow and Seymour's Host-Index
(125, p. 15), but the specimens referred to are all U. necator; the
same is also the case with the specimen in Ravenel's Herbarium at
the British Museum (S. Kensington) labelled ** U. Wallrothii Lév.
on Ampelopsis, Pennsylvania, Dr. Michener, ex Curtis.”

4. U. CLANDESTINA (Biv. Bern.) Schroet. [Fig. 93]

Erysiphe clandestina Biv. Bern. Stirp. Rar. Sic. man. 3: 20. A.
K F4 IBIE i

Abee adunca, var. ulmorum Wallr. Berl. Ges. Nat.
Freund. Verh. 1: 37. 1819; Wallr. Fl. Crypt. Germ. 2: 755.
1833.

Erysibe adunca, var. ulmorum Lk. in Willd. Sp. Pl. 6: 112.
1824; Rabenh. Krypt. Fl. Deutschl. 1: 236. 1844.

Erysiphe adunca Fr. Syst. Myc. 3: 245 (partim). 1829.

E. ulmi Cast. Cat. Pl. Mars. 192: 1845.

E. adunca, var. ulmorum Dur. & Mont., Fl. d'Algér. (Crypt.)
567: 1846-9

98 A MONOGRAPH OF THE ERYSIPHACEAE

Uncinula Bivonae Lév. Ann. Sci. Nat. IH. Iun: Hier dae dee a
1851; Sacc. Syll. Fung. 1: 6. 1882; Wint.; Rabenh. Krypt.
Fl. Deutschl. 17: 40. 1884; Jacz. Bull. l'Herb. Boiss. 4: 741.
1896.

Erysiphe Bivonae Tul. Sel. Fung. Carp. I: 200. 1861.

- Uncinula clandestina (Biv. Bern.) Schroet.; Cohn's Krypt.
Pl. Schles-.3.-. 245. -: 12003.

Exsicc.: Rab. Fung. Eur. 2030; Fckl. Fung. Rhen. 698;
Rehm. Ascom. 400; Desmaz. Pl. Cr. Fr. ed. 1, ser. 1, 920, and
“ed: 2, &er. 1, 220; Sacc. Myc Ven. 617; de Ihim. Myc:
univ. 755; Rab. Herb. Myc. ed. 2, 466; *Wartm. & Wint.
Schweiz. Krypt. 824.

Amphigenous : mycelium evanescent, or subpersistent as a very
thin effused film; perithecia closely gregarious in small patches,
or scattered over the surface of the leaf, rounded-lenticular, 85-
115 # in diameter, averaging 95 y, cells 10-14 # wide: append-
ages few, 9-25, rarely 25-30, usually about 15, equalling or (usu-
ally) slightly exceeding the diameter of the perithecium, simple,
colorless, aseptate, or occasionally septate near the base, thick-
walled and usually rough below, thin-walled and swollen into a
somewhat club-shaped apex above ; asci usually 4, rarely 3, 5, or
6, broadly ovate to globose, with or without a very short stalk,
40-45 x 32-40 p, averaging 45 X 35 A; spores 2, very rarely 3,
30-34 X 15-18 p, sometimes slightly curved.

Hosts.—Ulmus campestris, U. montana.

Distribution.—EvRorx : England (239), France, Belgium (209),
Germany, Switzerland, Italy, Austria-Hungary, Poland.

AFRICA: Algeria.

Asia: Japan.

A well-marked species in the few, somewhat club-shaped ap-
pendages and the 2-spored asci.

U. clandestina is not known to occur in America, all the rec-
ords of its occurrence in the United States being erroneous, and
mostly referring to U. macrospora. The plant recorded as U.
Bivonae by Cooke and Peck (9o, p. 11) is U. Clintonü, and the
host-plant is Tiia Americana, not Ulmus as stated. The claim
of U. clandestina to be considered as British rests on the authority
of Cooke, who records (239) this species as growing on the elms
in the Royal Gardens, Kew; I cannot, however, find specimens
from this locality in this author’s herbarium at Kew. The African

UNCINULA 99

(Algerian) specimen is in Montagne’s herbarium in the herbarium
of the Paris Museum. The Japanese example (now in the Kew
Herbarium), on Ulmus campestris, was sent to me by Prof. Miyabe,
and agrees perfectly with European specimens. This is the first
record of U. clandestina from Asia.

5. U. necator (Schwein.) Burr. [Fig. 86]

Erysiphe necator Schwein. Syn. Fung. Am. Bor. 270. 1834;
Sacc. Syll. Fung. 1: 22. 1882.

E. Tuckeri Berk. Journ. Hort. Soc. Lond. 9: 66. 1855; de
Bary, Beitr. Morph. Phys. Pilz. 1: $ xiii. 50. 1870; Sacc. Syll.
Fung. 1: 20. 1882; Wint. in Rabenh. Krypt. Fl. Deutschl. 1°:
34. 1884.

Sphaerotheca Castagnei, var. vitis Fckl. Symb. Myc. 79. 1869-
70.

Uneinula Americana E. C. Howe, Journ. of Bot. II. 1: 170.
1872; Sacc. Syll. Fung. 1: 8. 1882.

. U. spiralis Berk. & Curt. Grevillea, 4: 159. 1876; Atkins,
Journ. Elisha Mitch. Sci. Soc. 7: 66. 1891; Jacz. Bull. l Herb.
Boiss. 4: 739. 1896.

U. subfusca Berk. & Curt. Grevillea, 4: 160. 1876.

U. spiralis, var. racemosum 'Thüm. Pilz. des Weinst. 12. 1878.

U. ampelopsidis Peck, Trans. Albany Inst. 7: 216. f. 16-78,
1872; Peck, Reg. Rep. 25: 96. 1873; Sacc. Syll. Fung. 1: 7.
1882 ; Burr. & Earle, Bull. Ill. State Lab. Nat. Hist. 2: 406. f. 5.

U. necator (Schwein.) Burr.; Ell. & Ever. N. Amer. Pyren.

I5. 1802.
Erysibe Tuckeri (Berk.) Schroet. ; Cohn's Krypt. Fl. Schles.
3: 241. 1203

Exsicc.: Rab.-Wint. Fung. Eur. 3745 ; Ellis, N. Amer. Fung.
133; de Thuem. Myc. univ. 1143, 19, 38; Roumeg. Fung. sel.
Exsicc. 4757; * Seym. and Earle, Econ. Fung. 4, 5; * Ell. and
Everh. Fung. Columb. 415; * de Thuem. Pilz. des Weinst. E

Amphigenous, mycelium usually subpersistent, very thin and
effused, or forming circumscribed patches, sometimes evanescent :
perithecia usually epiphyllous, sometimes hypophyllous, occasion-
ally occurring on the inflorescence, globose-depressed, more or less
scattered, 70-128 in diameter, averaging 98 y, cells distinct,

100 A MONOGRAPH OF THE ERYSIPHACEAE

rather irregular in shape, 10-20 0 wide, appendages very variable
in number and length, 7-32, rarely irregularly crowded and as
many as 40, I-4 times the diameter of the perithecium, smooth,
simple, septate, thin-walled, light or dark amber-brown in the
lower half, flexuous and flaccid when long, subrigid and straight
when shorter, apex more or less helicoid when mature, often
strongly so: asci 4-6, rarely 6-9, broadly ovate or ovate- oblong
to subglobose, with or without a short stalk, 5000 x 30-40 1;
spores 4-7, 18-25 X 10-12 p.

* Hyphasma, tenuissimum album, floccis valde tenuibus, or-
biculatum, non constringens. Sporangiolis minutissimis, raris,
fusco-nigris, globosis. Ubi omnino evoluta, etiam haec species
destruit uvas . . . in uvis Vitis Laóruscae varietatibus cultis in
vineis nostris " (Schwein, Zoe. cit.).

Hosts.—Actinidia arguta, A. Kolomikta, A. polygama, Ampe-
lopsis cuspidata (60), Vitis aestivalis (60), V. Californica (373), V.
cordifolia (97) (249), V. flexuosa, V. hederacea (Ampelopsis quin-
quefolia), Vitis Labrusca and var. Catawba, V. riparia (60), V. ru-
pestris (373), V. vinifera.

Distribution (of perithecial form only).—Evurore : France.

Asia: Japan.

NORTH AMERICA : United States—Maine, Massachusetts, New
York, Pennsylvania, Maryland, New Jersey, West Virginia (249),
Ohio, Michigan, Indiana, Alabama (12), Illinois, Mississippi, Wis-
consin, Missouri, Iowa, Kansas, Texas (373), New Mexico, South
Dakota (151), California. Canada—Ontario.

Uncinula necator is at once known by the colored appendages,
which are, however, very variable in number and length.

The form on Vitis hederacea (Ampelopsis quinquefolia) is the
Uncinula ampelopsidis of Peck (U. subfusca Berk. and Curt.) and
at first sight seems to be distinct in the shorter, fewer (7-22) ap-
pendages, 1-3, usually 177 times the diameter of the perithecium,
not flexuous nor flaccid, and distinctly wider both in the lower
half (7-8 » wide), and towards the apex (8-10 nl These charac-
ters are shown by most forms on this host-plant, and were they
confined to this might entitle the plant to a varietal rank. But, as
most American mycologists now admit, they are not so. In the
ordinary examples of U. necator on Vitis Labrusca, V. vinifera, etc.,
the long appendages are about 5 x wide, flexuous and weak, but

UNCINULA 101

in the forms where the appendages tend to become shorter they
also immediately become wider, more rigid, and less flexuous, and
one is finally forced to the conclusion that “ U, ampelopsidis”’ is
but the last member of a chain of closely connected forms.

The occurrence of U. necator on species of Actinidia—a genus
of plants belonging to Ternstroemiaceae, an order in no way related
to Vitaceae—is very interesting, not only because the vine mil-
dew has hitherto been supposed to be confined to vines, but also
for the evidence it gives on the question, mentioned below, of the
native country of U. necator. Professor Miyabe sent me numerous
specimens (now in the Kew Herb.) of this form from Japan as
“ Uncinula actinidiae" Miyabe mss., but on examination the speci-
mens proved to agree well with certains forms of U. necator from
America. . Some of the Japanese specimens have perithecia with
few (about 8), short, wide appendages, 1—1 14 times the diameter of
the perithecium ; others have more numerous, sometimes irreg-
ularly crowded appendages, up to 28 in number, flaccid and three
times the diameter of the perithecium. These Japanese specimens
further strengthen the view that no sharp line can be drawn be-
tween the long- and short-appendaged forms of the present plant.
Some of the appendages of the Japanese specimens show a dis-
tinctly swollen base (Fig. 86). The apex of the appendages, when
mature, is strongly helicoid.

U. necator, or “ Oidium Tuckeri” as the conidial stage has long
been called in Europe, is well known as the vine mildew, a dis-
ease which has caused the most serious injury to cultivated vines
in both the Old and the New World. The literature concerning
“ Oidium Tuckeri,’ dealing with its systematic position, until quite
recently a matter of doubt, its appearance, mode of attack, reme-
dies, etc., is so vast that only a few references to the most impor-
tant works can be given here. Briefly, the history of this vine
mildew is as follows: In 1847 Berkeley (27) wrote in the Gard-
eners’ Chronicle that “ The grapes in the neighborhood of Margate
(England) have for the two last years been attacked by a peculiar
mildew of a most destructive character.” Berkeley named the
fungus Oidium Tuckeri, but even here hinted of its connection wi
an Erysiphe. The disease appeared almost immediately in all the
vineyards of the Mediterranean region, and by 1851 it had been

102 A MoNoGRAPH OF THE ERYSIPHACEAE

observed in France, Switzerland, Germany, Italy, Asia Minor,
Syria, Algeria, etc.; in 1852 it caused wholesale destruction in
Madeira ; in 1866-7 it was recorded from Australia ; it is common
throughout the United States, has lately occurred in Brazil and has
been reported on vines in Japan ; it is now, in fact, a disease almost
certain to appear wherever grapes are grown.

Fortunately, a cheap and reliable remedy has been found
against the vine mildew in the form of sulphur (flowers of sulphur,
or solutions of the sulphide), and the disease is now held com-
pletely in check by means of the use of this fungicide. Galloway
(137) (138) recommends the following method: 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 ob-
tained when the applications are made 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 treating this disease with a solution made by
dissolving half an ounce of potassium sulphide to the gallon of
water. (In preparing the solution, half an ounce of the “ liver of sul-
phur ” was dissolved in one pint of hot water ; as soon as dissolved,
the cold water (1 gallon less 1 pint) was poured with the hot solu-
tion, and the whole immediately strained through a thick osnaburg
cloth into a tin can and closely stopped.) This preparation is
cheap and can be quickly and effectually applied with any of the
well-known spraying pumps. The greatest care should be exer-
cised in making the second spraying, which should be at the same
time as that mentioned for the flowers of sulphur, in order to pro-
tect the blossoms from the fungus. For other preparations, and
their method of application, etc., reference may be made to Viala
(373)-

It is important to distinguish clearly between the two diseases
that have been called the “vine disease” or “ vine mildew,” the
one due to the attacks of ‘‘ Oidium Tuckeri,’ the other to those of
Peronospora viticola, as the remedies for the latter (Bordeaux mix-
ture, l’eau céleste, sulphate of copper) have been found to be of no
effect against Odium Tuckeri. It is therefore well to adopt the

UNCINULA 103

distinctive names proposed by Riley for these two diseases, and
now generally in use in America, viz., powdery vine mildew for
U. necator (Oidium Tuckeri) and downy vine mildew for Perono-
spora viticola.

Although Oidium Tuckeri was so terribly prevalent in Europe
since its appearance in 1845-6, no perithecia were found associ-
ated with it for the first 47 years of its occurrence, and during this
time its true systematic position was much questioned. Berkeley
(32), recognizing its close resemblance to the conidial stage of
species of Erysiphe, changed the name in 1855 to Erysiphe Tuckeri.
When, however, the Uncinula on the American vines became
generally known, it began to be suggested that “ Oidium Tuck-
eri” might be merely the conidial stage of this fungus ; and Far-
low (121) and Viala and Ravaz (375) among others pointed out
the exact resemblance of the American and European Oidium
forms. Many mycologists, however, would not admit the iden-
tity of the two, contending that the Osdium Tuckeri of the Old
World had larger conidia than those of the American U necator,
Fuckel considered Oidium Tuckeri to be the conidial condition of
a variety of Sphaerotheca Castagnei ; whilst others believed it to
be that of Erysiphe communis (E. polygoni). In 1844 Berkeley
recorded (37) the occurrence of a species of Erysiphe, apparently
identical with Æ communis,’ growing with U. necator on Vine
leaves sent from Washington. [This was probably either a stray
perithecium of Æ. polygoni, or probably immature examples (with
young straight appendages) of C. necator.| However, in 1892
Couderc (93) discovered in several places in France, perithecia on
vines attached by “ Oidium Tuckeri,’ and showed that they were
identical with those of U. necator. In the following year Viala
(1894) reported an abundant formation of perithecia of U. necator,
or diseased vines in many parts of France. This unusual pro-
duction of the perithecial stage has been attributed to the sudden
alternation of high and low temperatures which took place in
these years. Through the kindness of Mr. Jaczewski I have seen
specimens (now in the Kew Herbarium) of French examples of
U. necator and have found them to agree in every way with Ameri-
can examples of this species.

Mycologists, e. g., de Bary, von Mohl, Viala, Worthington G.

104 A MONOGRAPH OF THE ERYSIPHACEAE

Smith—have considered that “ OzZium Tuckeri"—the conidial
stage of U. necator—was originally brought from the vines of
America to Europe, and thus introduced at once spread over all
the Mediterranean vineyards, but that from some cause due to the
effect of the change of environment, the fungus lost the power of
producing perithecia. Several fungous diseases are now known to
have been introduced in this way from America to Europe, and so
long as America was the only native country known for U. necator,
the idea of the American origin of “ Oidium Tuckeri” was natu-
ral, although it appears that no direct evidence on the point ex-
ists; now, however, that we know that U. necator is native to the
Old World, occurring on native plants in Japan, it is a question
whether it may not have invaded Europe from the East. Vitis
vinifera is wild in western temperate Asia (and perhaps in the
Mediterranean region), being especially frequent in Armenia, Cau-
casia, and the region round the Caspian Sea, and it is possible
that U. necator will be found to occur in wild vines in these coun-
tries. It is, of course, possible that “ Oidium Tuckeri’’ existed on
European vines before the great outbreak of it in 1847—52——and
there is some evidence favorable to this view—but that, at this time,
for some unknown reason it first increased to such an extent as to
form a dangerous disease. (For further details of the history of
“ Oidium Tuckeri" reference can be made to the following authors :
Viala (373), von Mohl (250, 251, and 252) and Montagne (254).

As it appears that the formation of perithecia is exceptional in
U. necator on European vines, the question presents itself as to
how the fungus, in this absence of ascospores, bridges over the
period of winter. It has been stated this is effected by a hibernat-
ing mycelium ; other authors, e. g., Viala, suppose that the conidia
have acquired the power of being able to hibernate.

It is worth noting that Viala tried many experiments with the
view of seeing if vines could be infected with the conidia of Zry-
siphe polygoni, and conversely, if the host-plants of E polygoni
could be attacked by “ Oidium Tuckeri,” but with negative results
in both cases.

Galloway (139) has made some valuable observations on the
ripening of the perithecium and the germination of the ascospores
of the present species. Infected leaves of Ampelopsis and Vitis

UNCINULA 105

were placed in the autumn in sacks on the open ground. Although
the appendages of the perithecium soon disappeared, the asci and
spores underwent little change until the end of December, when
. many of them were found to be dead or more or less collapsed.
All attempts to germinate the ascospores before January failed,
and it was only after repeated trials through February and March
that success was attained. The perithecia were from time to time
removed from the leaves and placed in a drop of sterile water in
Van Tieghem cells. In one instance, which may be taken as
typical of the usual development, some perithecia were placed in
cells on January 7th. Twenty days later no change had taken
place, the cell having been kept free from jars. The cell was then
placed under the microscope, and gently jarred with a needle,
whereupon one of the perithecia suddenly burst and the asci
escaped into the surrounding water. The first ascus was violently
ejected from the perithecium to a distance equal to about twice
the length of the former. This was immediately followed by a
second and a third ejected in the same way. The ruptured wall
of the perithecium then closed and no more asci escaped. No
sooner were the asci free than their spores began to escape or else
to break up within the ascus. In the former case they escaped
from the top, side or bottom of the ascus. A large part of the
spores burst as soon as they were set free. Nearly all the spores
that failed to burst began to send out germ tubes in four or five
hours, and at the end of twelve hours the tubes had reached a
length twice that of the spore or more. A number of attempts
were made to infect leaves with ascospores, but the results were
in every case negative.

6. U. cırcınaTa Cooke & Peck

U. circinata Cooke and Peck, Journ. of Bot. II. 1: 12. 1872;
Peck, Trans. Albany Inst, 7: 214. f. 7-9. 1872; Peck, Reg.
Rep. 25: 96. 1873; Sacc. Syll. Fung. 1: 8. 1882; Burr and
Earle, Bull. Ill. State Lab. Nat. Hist. 2: 408. 1887; Burr. ; Ell.
& Everh. N. Amer. Pyren. 17. 1892.

Exsıcc.: EI. N. Amer. Fung. 427; de Thüm. Myc. Univ.
2051; Roumeg. Fung. select. exsicc. 4927; Ell. and Everh.
Columb. Fung. 110; *Seym. and Earle, Ecan. Fung. 115, 116.

106 A MONOGRAPH OF THE ERYSIPHACEAE

f, averaging 190 p, cells obscure, irregular, 10-14 1 wide; ap-
pendages very numerous, usually densely crowded, just falling
short of the diameter of the perithecium, simple, smooth, aseptate,
rather delicate, about 5 o wide, thin-walled and hyaline throughout,
apex simply uncinate; asci 9-26, usually about 1 5, narrowly
ovate or cylindrical, sometimes ovate-oblong, with or without a
short stalk, 68-86 x 29-40 p; spores 8, sometimes 7, 18-22 x
10-14 f.

Hosts —Acer dasycarpum, A. Pennsylvanicum (60), A. rubrum,
A. saccharinum, A. spicatum.

Distribution. —NORTH AMERICA : United States—Maine (163),
Vermont, Massachusetts, New York, Pennsylvania, South Carolina
Ohio, Michigan, Indiana, Alabama, Illinois, Wisconsin, Missouri
(363), Iowa. |Canada— Ontario.

“ This species is related to U. bicornis [ U. aceris], from which
it is distinguished by its hypogenous habit, more numerous spo-
rangia and always simple appendages. It usually occupies the
whole under-surface of the leaf.” (Peck, 25 Rep.)

This distinct and endemic species, which apparently takes the
place of the European U. aceris on the maples of North America,
is somewhat intermediate between U. aceris and U. salicis, agree-
ing with the former species in the 8-spored asci and large perithecia,
and with the latter in the numerous, simple, thin-walled appen-
dages. From U. aceris, var. Tulasnei it differs in the more or less
evanescent mycelium, and thin-walled appendages. When well-
developed the appendages cover the whole of the upper half of the
perithecium.

7. U. PARVULA Cooke & Peck

U. parvula Cooke & Peck, Journ. of Bot. II. 1: 1 70 1572;
Burr & Earle, Bull. Ill. State Lab. Nat. Hist. 2: 409. 1887; Sacc.
Syll Fung.9: 367. 1891; Atkins. Journ. Elisha Mitch. Sci. Soc.
7: 67. 1891; Burr.; Ell. & Everh. N. Amer. Pyren. 18. 1892.

U. Torreyi Gerard, Trans. Albany Inst. 7: 21 S Ix

Amphigenous ; mycelium evanescent ; perithecia usually hypo-
phyllous, scattered, globose-depressed, small, 86-122 o in diam-
eter, averaging 98.4, cells about ton wide; appendages numer-

UNCINULA 107

ous, 50-160, %-% the diameter of the perithecium, simple,
colorless, aseptate, becoming more or less thick-walled through-
out, smooth, delicate, 3-4 » wide, slightly attenuated upwards,
apex simply uncinate ; asci 5-8, broadly ovate with or without a
short stalk, 50-64 x 34-38; spores 4-7, usually 6, 20-24
x 10-12 p.

Hosts.—Celtis Americana, C. occidentalis.

Distribution —NoRTH America: United States—New York,
New Jersey, South Carolina, Indiana, Alabama (12), Illinois, Mis-
sissippi, Missouri, Iowa, Kansas (386), Washington. “ From the
Atlantic coast to Washington ; not apparently abundant, but often
collected from widely separated localities ” (Burrill (60)).

An interesting species (endemic to North America), distinct
from U. salicis in the small perithecia with shorter, more delicate
and narrower appendages, which become more or less solid through
obliteration of the lumen at maturity.

8. U. MACROSPORA Peck

U. macrospora Peck, Trans. Albany Inst. 7: 215. f. 4-6. 1872;
Peck, Reg. Rep. 25: 96. 1873; Sacc. Syll. Fung. 1: 7. 1882;
Burr. & Earle, Bull. Ill. State Lab. Nat. Hist. 2: 407. 1887 ;
Atkins. Journ. Elisha Mitch. Sci. Soc. 7:66. 1891; Burr. ; Ell.
& Everh. N. Amer. Pyren. 18. 1892.

U. intermedia Berk. & Curt. Grevillea, 4: 160. 1876; Sacc.
Syll. Fung. 1: 7. 1882.

Exsicc.: Ell N. Amer. Fung. 426; de Thüm. Myc. Univ.
2053; Rab.-Wint. Fung. Eur. 3244; *Seym. & Earle, Econ.
Fung. 154, 156a, 156b; TEI & Everh. Fung. Columb. 223, 414.

Amphigenous; mycelium evanescent, or subpersistent and

not or scarcely enlarged upwards, apex usually simply uncinate,
icoi 4-20, sub-pyriform

15-18 p.

108 A MONOGRAPH OF THE ERYSIPHACEAE

Hosts.—Ostrya Virginica, Ulmus alata, U. Americana, U. fulva.

Distribution —NORTH AMERICA: United States—Massachu-
setts, New York, North and South Carolina, Ohio, Michigan,
Indiana, Alabama, Illinois, Mississippi, Wisconsin, Missouri (363),
Iowa, Kansas, South Dakota (151).

Quite distinct from U. Bivonae, its nearest ally, in the larger
perithecia, with more numerous appendages and asci. U. Bivonae
is frequently recorded as occurring in America, but this is incorrect,
and the specimens so named have proved (with one exception) to
belong to the present species.

9. U. FLExuosa Peck. [Figs 83, 84]

U. flexuosa Peck, Trans. Albany Inst.7: 215. f. 70-12. 1872;
Sacc. Syll. Fung, 1: 8. 1882; Burr & Earle, Bull. Ill. State Lab.
Nat. Hist. 2: 408. 1887 ; Atkins. Journ. Elisha Mitch. Sci. Soc.
7: 66. 1891; Burr. ; Ell. & Everh. N. Amer. Pyren. 16. 1892.

Exsicc.: de Thüm. Myc. Univ. 2052; Ell. N. Amer. Fung.
661; Rab.-Wint. Fung. Eur. 3658; *Seym. & Earle, Econ.
Fung. 118a, 118b; YEI & Everh. Fung. Columb. 416.

Hypophyllous, or sometimes amphigenous; mycelium evan-
escent or under surface of leaf, but sometimes subpersistent in very
thin patches on the upper surface; perithecia more or less scat-
tered, rounded-lenticular, 85-156 " in diameter, averaging 100 D.
cells distinct, averaging 17 & wide ; appendages variable in num-
ber, 14—60, usually about 30, about equalling the diameter of the
perithecium, simple, colorless, and aseptate, hyaline, enlarged, and
abruptly flexuose upwards, becoming refractive and thick-walled,
and often rough below; asci 4-11, broadly ovate, with a short
stalk, 50-58 x 30-38 5; spores usually 8, sometimes 7 or (rarely)
6, 18-22 x IO p.

“The flexuose appendages are characteristic of this species.
They sometimes appear as if twisted like the blade of a screw-
auger (Peck, loc. cit.).

Hosts —Aesculus arguta (386), A. flava (60), A. glabra, A.
Hippocastanum, A. Pavia.

Distribution. —NoRTH AMERICA: United States—Massachu-
setts, New York, New Jersey, South Carolina, Ohio, Indiana,
Alabama, Illinois, Mississippi (361), Missouri, Kansas (386).
Canada—Ontario.

UNCINULA 109

Very variable in the size of the perithecia and number of the
appendages, but easily recognized by the abruptly undulated
upper half of the appendages (Fig. 83) and the usually 8-spored
asci.

Saccardo’s description of U. flexuosa, “ peritheciis 80-90 p d.,
appendicibus 15-25 ” applies only to the small form of the spe-
cies, such as, for instance, the specimen in the Kew Herbarium
from South Carolina (** C. H. P., 192), where the perithecia are
frequently only oo nu in diam., with 25 or fewer appendages.
Peck and Saccardo compare U. flexuosa with U. salicis, but there
is no close relationship between these two species, and it is U.
Clintonii that is undoubtedly the nearest ally to the present spe-
cies. The small forms of U. ffexuosa, mentioned above, approaches
certain examples of U. Clintonii very closely, and can only be
separated by the—in this form—slightly-undulated appendages,
which are shorter, and by the 8-spored asci.

10. U. Cuintont Peck. [Figs. 81, 82]

U. Clintomi Peck, Trans. Albany Inst. 7: 216. f. 73-75.
1872; Peck, Reg. Rep. 25: 96. 1873; Sacc. Syll. Fung. 1: 7.
1882; Burr.; Ell & Everh. N. Amer. Pyren. 15. 1892.

Exsicc.: Ell. N. Amer. Fung. 662; *Seym. & Earle, Econ.
Fung. 105; *Rab.-Wint.-Pazsch. Fung. eur. 4051; *ElL &

. Everh. Fung. Columb. 413.

simple, colorless or sometimes brownish-amber at base, refractive,
thick-walled and often rough below, smooth, thin-walled and
swollen above, measuring 20-30 H across the simply uncinate
clavate apex ; asci 4-10, or 2-4, usually 3 (on Zelkova), broadly
ovate to subglobose, very shortly stalked, 40-62 x 34-40 /^;
spores 3—7, usually 5-6, more or less crowded in the ascus, 20
—25 X 10-13 4.

Hosts — Aphananthe aspera, Tilia Americana, Zelkova acumi-
nata.

Distribution. —Asıa : (on Aphananthe and Zelkova) Japan.

110 A MONOGRAPH OF THE ERYSIPHACEAE

NORTH AMERICA : (on 7ilia) United States: New York, Mary-
land, Ohio, Michigan, Indiana, Illinois, Wisconsin, Iowa, Minnesota;
Canada— Ontario.

This species shows great affinity with the European U. pru-
nastri, from which it differs in the usually fewer and always broader
asci, larger spores, and usually more swollen apex of the append-
ages. With regard to the last character, however, there is cer-
tainly much variation, as a glance at Fig. 81 will show, and it
would be unsafe to place any great value on this point. _

U. Clintonü has been hitherto regarded as confined to North
America, where it occurs not unfrequently on the single host-plant,
Tilia Americana, Among the Japanese specimens of Erysiphaceae,
however, sent to me by Professor Miyabe there occurs an Uneinida,
which, although differing slightly from the American examples
must, I think, be included under the present species. Two speci-
mens were sent, one on Zelkova acuminata (Z. Keaki) from Kobe,
(K. Miyabe, Aug. 1889), the other on Aphananthe aspera from
Tokyo (K. Sengoku, Oct. 1898).

The first specimen sent was that on Zelkova, and as this differed
in several characters from the American form, I was at first in-
clined to rank it as a variety minor under U. Clintonii. The speci-
mens showed these characters: mycelium epiphyllous, subpersis-
tent, very thin, effused; perithecia uniformly scattered over the
upper surface of the leaf, small, 64-86 p. in diameter, averaging
78 », cells 10-20 4 wide; appendages 12-25, unequal in length,
from equalling to twice exceeding the diameter of the perithecium,
colorless, simple, thick-walled, refractive and narrow (about 47
wide) at the base, thin-walled and enlarged upwards, about 20 D
wide across the simply uncinate apex ; asci 2-4, usually 3, 40-50
X 34-40 p, subglobose, with or without a very short stalk ; spores
3-5, crowded in the ascus, 20-24 x 10-12 p.

This “ var. minor” could be thus contrasted with the American
plant: U. Clintonii (American) ; perithecia 80-1 30 # in diameter,
appendages 22-30 wide across the apex, asci 4-10. “Var.
minor” (Japanese); perithecia 64-86 p in diameter, appendages
about 20 wide across the apex, asci 2-4, usually 3.

The second Japanese specimen sent (on Aphananthe), however,
broke down these distinctions, as this form has perithecia 75-

UNCINULA 111

100 # in diameter, appendages 20 » wide across the apex, and from
3to 6 asci. In the American examples the appendages vary from
10 to 35 in number, and are usually about 20, and are from I to 2,
or even 274 times the diameter of the perithecium ; in the Japanese
example on Aphananthe the appendages vary from 7 to 18, and are
usually about 12, and equal or slightly exceed the diameter of the
perithecium. They are also, as a rule, slightly wider at the base
than is usually the case in American U. Clintonit.

Both the Japanese specimens agree with U. Clintonit in the small
subglobose asci, and spores distinctly larger than those of U.
prunastri, and it seems best therefore, so long as U. Clintonit and
U. prunastri are maintained as distinct species to regard the Japa-
nese plants as belonging to the former species. It may be pointed
out that these forms on Ze/kova and Aphananthe differ just as
slightly from one another, as either of them does from typical U.
Clintonit. ;

II. U. GENICULATA Gerard

U. geniculata Gerard, Bull. Torr. Club, 4: 48. 1873; Sacc.
Syll. Fung. 1:8. 1882; Burr. ; Ell. & Everh. N. Amer. Pyren.

Exsıcc. : Rab.-Wint.-Pazsch. Fung. Eur. 3955; *Seym. &
Earle, Econ. Fung. 152.

Epiphyllous; mycelium thin, arachnoid, forming definite
patches, or more or less effused, sometimes evanescent ; perithecia
subgregarious on the patches, or scattered, small, 90-120 nm in di-
ameter, usually about 100 y, globose-depressed, cells rather irreg-
ular, 10-15 wide ; appendages 24-46, 1% to twice the diameter
of the perithecium, delicate, 3-4 /^ wide, some usually abruptly
bent or geniculate, simple, colorless, aseptate, thin-walled, smooth
or minutely rough at base, apex simply uncinate: asci 5-8,
broadly ovate, very shortly stalked, 48-56 x 34-38 #: spores
4-0, 22 x I2 f

Flost.—Morus rubra.

Distribution —Nortu America: United States—New York
(144), Indiana, Alabama, Illinois, Missouri, Kansas.

This species approaches slightly certain forms of U. salicis, but
is distinct in the smaller perithecia, with fewer delicate narrower
appendages, which are not enlarged but usually slightly attenu-
ated upwards. In U. salicis the appendages are, as a rule, much

112 A MONOGRAPH OF THE ERYSIPHACEAE

more numerous, and always stouter and wider (5-7 p wide).
Moreover, in most perithecia of U. geniculata at least one or two
of the appendages show an abrupt geniculate bend, and this char-
acter, when present, is quite sufficient to distinguish the present
plant from all the species of Uncinula except some forms of U.
salicis, var. Miyabei, and from this variety U. geniculata differs in
the much narrower appendages, not enlarged upwards. Some-
times, however, all the appendages are straight, and U. geniculata
is then best known by the rather few, delicate, narrow append-
ages. The asci are described as being 6-spored, but they are fre-
quently 4-spored. The fewer and much longer appendages at
once separate the present plant from U. parvula.

U. geniculata is confined to the United States ; the record by
Issatchenko (171) of its occurrence in Russia rests on an error.

Among the specimens of Erysiphaceae sent to me from the
Herbarium of the U. S. Department of Agriculture was one labelled
“ Erysiphe cichoracearum DC. On Hydrophyllum appendiculatum.
Crawfordsville, Indiana. E. M. Fisher, Oct., 1890. No. 1003.”
This specimen showed, on examination, only perithecia of a species
of Uncinula scattered irregularly over the surface of the leaf.
Feeling doubtful if this Uneinwla really originated on this host-
plant, I wrote to Professor Galloway on the subject, who replied,
“I regret to state that we are unable to give you any information:
in regard to the care of the material labelled ZE cichoracearum on
Hydrophyllum appendiculatum. It has for some years been in
mycological envelopes, labelled as above, and whether it was previ-
ously in contact with any host bearing Uxcinu/a, it is now impossi-
ble to ascertain. Nothing but perithecia of Uncinula appear to be
upon several specimens examined to-day, and we are fearful that
the first determination was an error.” After a careful comparison
of the perithecia, I found them to agree in all characters with those
of the present species— U. geniculata—which has been recorded
only on Morus rubra. The leaves of the Zydrophyllum show
patches of mycelium on the upper surface, and on these as well as
on parts of the leaf without mycelium, the perithecia of U. genic-
ulata are scattered. These perithecia appear more or less loose,
and can be easily lifted off with a needle, and I was not able to
observe any connection with the mycelium, nor the occurrence of

UNCINULA 113

any young perithecia. On the whole, it must be left doubtful for
the present, for reasons stated in the preface whether //ydro-
phyllum appendiculatum is really a host-plant of U. geniculata. I
have gone fully into the above case because it affords an exact
parallel to that of the single occurrence of U. sa/icis on Scutellaria
lateriflora.

12. U. POLYCHAETA (Berk. & Curt.) ex. Ellis. [Fig. 89]

Erysiphe polychaeta Berk. & Curt. Grevillea, 4: 159. 1876.

Uncinula Lynchii Speg. Fung. Argent. Pug. 2: 17, 44. 1880.

Pleochacta Curtisii Sacc. & Speg., Sacc. Michelia 2: 373.
1881 ; Sacc. Syll. Fung. 1: 9 (partim). 1882 & Addit. ad vols. 1-
4:2. 18806.

Uncinula polychaeta (Berk. & Curt.) ex. Ellis in Journ. Myc. 2:
43. 1886; Tr. & Gall. Bot. Gaz. 13: 29 syn. excl. partim. (cum
icon.) 1888 ; Massee, Grevillea, 17: 78. 1889 ; Sacc. Syll. Fung.
9:367. 1891; Atkins. Journ. Elisha Mitch. Sci. Soc. 7: 67. pl.
I. f. 5, I1. 1891; Burr.; Ell. & Everh. N. Amer. Fyren. 18.
1892.

Exsicc.: Rav. Fung. Carol. Exsicc. fasc. 4, 68 & Ell. & Everh.
N. Amer. Fung. 2113, sub U. polychaeta Berk. & Curt.; *Seym.
& Earle, Econ. Fung. 149; *Speg. Dec. Myc. Argent. 39.

Hypophyllous ; mycelium dense, forming irregular whitish `
patches, or completely evanescent ; perithecia gregarious on the
patches of mycelium, or when these are absent, scattered over the
surface of the leaf; rounded-lenticular, very large, 215-320 tin
iameter, averaging 255 pn. cells obscure, appendages very numer-
ous, usually about 200, closely crowded, 1(—24 the diameter of
the perithecium, smooth, thick-walled with the lumen more or less
completely obliterated, simple, colorless, narrowed upwards to the
closely uncinate apex, aseptate; asci very numerous, 34—66,
cylindrical or subcylindrical, rarely oblong, more or less abruptly
attenuated into an evident stalk, 70-84 x 20-26 p; spores 2-3,
(very rarely 4), 26-30 x 12-14 P

Hosts.—Aphananthe aspera, Celtis occidentalis, C. tala, C.
Mississippiensis, Celtis sp. (Chinese).

Distribution. —Asıa: China (Yunnan), Japan.

Nortu America: United States—South Carolina, Alabama,
Mississippi.

Sours America: Argentine (Buenos Ayres).

114 A MONOGRAPH OF THE ERYSIPHACEAE

Very distinct in the large perithecia—the largest in the genus
—the closely crowded short appendages, more or less attenuated
upwards into the small closely involute apex, and the very numer-
ous 2-3-spored asci.

U. polychaeta has been recorded hitherto only from America,
but specimens sent to me as “ Uncinula adunca Lev. sur Celtis,
Yunnan, China (leg. Delavay),” by M. Patouillard prove to be-
long to the present species, and so give an interesting extension to
the range of this species hitherto supposed to be endemic to
America. Whilst agreeing in all other respects, the Chinese
specimens differ in having asci which are regularly 3-spored ; in
American examples the asci, in my experience, are nearly always
2-spored, with rarely a rudimentary third spore present. Tracy
and Galloway (362), however, in their remarks on the American
plant, say “spores usually two, oval, subhyaline, nearly filling the
ascus. Sometimes three or even four spores are found in an as-
cus. When three occur in an ascus, two are of nearly the usual
size, and the third quite small, and when four occur all are small.”
It would thus obviously be unsafe to separate in any way the
Chinese from the American plant.

Since the above remarks were written Prof. Miyabe has sent
me a plant named “Uneinula n. sp. related to U. polychaeta, but
trisporous. On Aphananthe aspera, Tokyo, Japan, October 29,
1895 (K. Sengoku).” In this Japanese example most of the asci
are 3-spored, although they may be frequently found only 2-
spored, and the fungus is evidently to be referred to U. polychaeta.

It is necessary to keep the specific name polychaeta for the
present species. It was described as Erysiphe polychaeta Berk. &
Curt. and stands first on the same page where Uncinula polychaeta
Berk. & Curt. was published. The latter species has been re-
named U. confusa by Massee.

The genus Pleochaeta Sacc. and Speg. Michelia 2: 373. 1881
must be rejected, being founded on young examples of the present
species in which the appendages were immature and without the
uncinate apex. Ellis (1 16) and Massee (238) have pointed this
out, and Saccardo himself has, in the Sylloge, 9: 367. 1891
withdrawn the genus. [Pleochaeta, however, is still kept up in a
subsequent paper by Saccardo (313) published in 1896 and in the

UNCINULA 115

Syll. Fung. 14: 16. 1899; Lindau also (in Engler and Prantl’s
Pflanzenfamilien, 1': 328, 331. 1897) retains the genus].

13. U. confusa Massee

Uncinula polychaeta Berk. & Curt. Grevillea, 4: 159. 1876.

Pleochaeta Curtisii Sacc. & Speg.; Sacc. Syll. Fung. 1: 9
(partim). 1882.

Uncinula confusa Massee, Grevillea, 17: 78. 1889; Sacc.
Syll. Fung. 9: 367. 1891; Burr; Ell & Everh. N. Amer.
Pyren. 19. 1892.

“ Peritheciis sparsis ; appendicibus multis. On leaves of Ce/tzs
occidentalis, Car. No. 5619. Perithecia scattered ; appendages
about 28, 1 14 longer than the diameter of the perithecia, hyaline.”
(Berk. Grevillea, 4: 159. 1876).

* Hypophyllous; mycelium very scanty, not forming spots;
perithecia scattered, usually not more than two or three on a leaf,
150-200 yz diam., appendages 25—28, simple, colorless, very slen-
der, about 300 x 2-3 ww; apices strongly involute, not at all in-
crassated ; asci about 25, cylindrico-clavate, tetrasporous; spores
colorless, simple, elliptic-oblong, 20 x 10 2” (Massee, Grevillea,
17: 77. .1889). :

Massee’s description was based on the result of an examination
of the type specimen of “Uneinula polychaeta” in the Kew Her-
barium. Unfortunately, I have not been able to find on this type-
specimen any perithecia which show the characters described by
Berkeley and Massee, but, curiously enough, I have found several
perithecia of Uncinula parvula on the leaf, agreeing perfectly with
this species in possessing a diameter of 100-110 p, 50-70 short,
narrow appendages, 5-6 broadly-ovate asci, and 4-7 spores.

The question naturally presents itself, Could this have been the ©
fungus examined by either Berkeley or Massee ? I do not think
this is possible. In Berkeley’s description the rather contradic-
tory characters, “ appendicibus multis" and * appendages about
28” appear, but, what is very important, on the type sheet at
Kew, Berkeley has given a drawing of a perithecium showing 28
appendages, slightly exceeding the diameter of the perithecium.
In the diagnosis, moreover, the appendages are described as “ 1%
longer than the diameter of the perithecia.” In Massee’s descrip-
tion the additional characters given, “ perithecia 150-200 /4 diam.,

116 A MONOGRAPH OF THE ERYSIPHACEAE

asci about 25, cylindrico-clavate’’ quite prohibit us from suppos-
ing that U. parvula was under observation.

We seem forced to the conclusion, therefore, that U. confusa
is a distinct species, one that has apparently disappeared since its
original discovery.

U. confusa and U. polychaeta were for some time greatly con-
fused with one another. Both species were originally described
on page 159 of Grevillea, 4: 1876; the former appears first on
the page as “Erysiphe polychaeta Berk. and Curt."; the latter as
“Uncinula polychaeta Berk. and Curt." The essential characters
given for each were these: Æ. polychaeta, appendages many, about
equal to the diameter of the perithecium, straight, asci elongated,
clavate ; U. polychaeta, appendages about 28, 177 longer than the
diameter of the perithecium. As a matter of fact, the first species
proved to be a true Uncinula, and the description ** appendages
straight" referred only to the immature condition.

“Erysiphe polychaeta” has occurred in several places in North
America, whilst ** Unczuula polychaeta” has not been refound since
its original discovery. It was not unnatural, therefore, that many
botanists meeting with an Uncinula on leaves of Celtis should refer
it to the Uncinula polychaeta of Berk. and Curt., rather than to
the Arysiphe polychaeta of these authors. This was done by
Ravenel (Fung. Carol. Exsicc. fasc. 4: 68) and by Ellis and Ever-
hart in their Exsiccati (N. Amer. Fung. 2113). The same mis-
take was made by Ellis in the Journal of Mycology, 2: 52, 53.
1886, where an attempt was made to reconcile the description of
the few appendages of U. polychaeta Berk. and Curt. with the
presence of numerous ones in the plant under observation by say-
` ing “ The statement in Grevillea that the number of appendages is
about 28 is evidently a typographical mistake for 228," and finally
by Tracy and Galloway, who gave an excellent figure and descrip-
tion, and who similarly supposed that the description “about 28”
was probably a misprint for 280.

Massee (238) first pointed out that “ Erysiphe polychaeta ”
was an Uncinula, and that this was the species which the authors
mentioned above had had under observation, and wrongly identi-
fied with the “ Uncinula polychaeta” of Berk. and Curt. The
specific name “ polychaeta " having to be used, in accordance with

UNCINULA 417

the rules of priority for the Uneinula, originally called “ Erysiphe
polychaeta,” it became necessary to rename the Uncinula polychaeta
of Berk. and Curt, which is now known as Uncinula confusa
Massee.

14. U. AUSTRALIS Speg. [Fig. 61]

ncinula australis Speg. Fung. Guaran. Pug. I: 66, n. 167.
1886 ; Sacc. Syll. Fung., addit. ad. vols. I.—IV : 1. 1886; and 9:
366. 189r. ;

Epiphyllous; mycelium persistent, densely compacted and
effused over the surface of the leaf, or thinner and in scattered
patches; perithecia scattered, 120-138 “in diameter, globose-
depressed, cells small, about 8 x wide ; appendages numerous, 35-
60, 1%-1% times the diameter of the perithecium, simple,
colorless, aseptate, thin-walled throughout, rough and slightly
enlarged in the upper half, but not swollen at the apex, which is
simply uncinate ; asci about 10, broadly ovate, shortly stalked,
58—65 x 32-38 u; spores 8, rarely 7, 18-20 x 10-12

* Epiphylla; mycelium arachnoideum, grisecenti-album, late
folia ambiens, eisque arcte adnatum, tenue, compactiusculum, non
pulverulentum ; perithecia densiuscule hinc inde sparsa, globoso-
depressa, minuta (100-120 diam.) atra, glabra, membranaceo-
coriacella, contextu parenchymatico, parum perspicuo, fuligineo,
basi 20—40 appendicibus radiantibus ornata ; appendices divaricatae
(100-130 x 4-7), utrinque gradatim, attenuatae et laeves, medio
Saepius incrassatulae ac minutissime densiusculeque granuloso-
papillosae, apice saepius semel plus minus ve circinatae (rarius
rectae atque obtusata), hyalinae. Asci et sporae non visa." (Speg.,
loc. cit.)

Host.—Eugenia sp.

Distribution.—SovrH AMERICA : Paraguay.

The first description given above is drawn up from the speci-
mens in the Kew Herbarium, and in the Herbarium of the Paris
Museum, labelled ** B. Balansa, Pl. du Paraguay, 1878-1884.
Nr. 3814. Uncinula australis Speg. Fung. Guaran. pug. r: 00.
Feuilles d’ Eugenia. Naranjo, sur- la -Cordillere de Péribébuy, 24
mai 1883." I have seen no other examples. The original speci-
mens from which Spegazzini drew up his diagnosis, given above.
were too young to contain asci, and the description of the ap-
pendages as sometimes “straight and obtuse" doubtless refers to
the immature condition.

118 A MoNOGRAPH OF THE ERYSIPHACEAE

U. australis is apparently distinct from U. salicis in the 8-spored
asci.

15. U. Deravayi Patouill. [Fig. 88]

U. Delavayi Patouill. Journ. de Bot. 2: 217 (cum tcon.).
1888 ; Sacc. Syll. Fung. 9: 367. 1891.

Hypophyllous ; mycelium evanescent; perithecia subgrega-
rious, rounded-lenticular, 98-136 y in diameter, cells large, 15-20
D wide, appendages very few, 6-12, usually shorter than the di-
ameter of the perithecium, rarely slightly exceeding it, simple,
stout, 7-8 y wide near the base, hyaline, thin-walled and enlarged
at the apex, becoming thick-walled, refractive and sometimes rough
towards the base, usually slightly curved throughout their length,
colorless, aseptate; asci 4-11, broadly ovate or oblong, very
shortly stalked, 58-68 x 34-38 5; spores 6 or 7, rarely 5, 20-
22x 10-12 p.

Host — Ailanthus sp.

Distribution —Asıa : China (Yunnan).

Of a distinct habit in the short, stout, usually curved appen-
dages, not exceeding 12, and usually about 8 in number. U. Del-
avayt is most nearly allied to U. Sengokui, which differs in the
more numerous, crowded appendages, not or scarcely enlarged
upwards.

I am indebted to M. Patouillard for a specimen (now in the
Kew Herbarium) from which the above description was drawn up.

M. Patouillard gives (274) a good figure of the present species.

16. U. AUSTRALIANA McAlpine. [Figs. 94, 95]

U. Australiana McAlpine, Journ. Linn. Soc. N. S. Wales, 24:
302. M. 23. f. 5-9. 1899.

Amphigenous ; mycelium persistent or subpersistent ; perithecia
usually gregarious in patches on the mycelium, sometimes more
or less scattered, 90-140 y in diameter, usually about 11 5 æ, cells
10-15 4 wide; appendages 7-20, usually about 12, about equal-
ling the diameter of the perithecium, rarely I 14 times the diameter,
I-septate and colored pale- or dark-brown at the base (sometimes
one here and there aseptate and colorless), simple, smooth, thin-
walled, narrowed upwards when young, not enlarged upward when
mature, about 5 # wide in the upper half, apex usually helicoid ;
asci 3—5, broadly ovate to subglobose, with or without a short
stalk, 42-50 x 30-40; spores 5-7, rarely 8, 20-22 x 10-12 y.

UNCINULA 119

Hosts.—Lagerstroemia Indica, L. ovalifolia.

Distribution.—Asia: Japan (Sendai, K. Miyabe, Aug., 1893,
and Tokyo, S. Hori., 1896).

AUSTRALIA: New South Wales Botanic Gardens, Sydney.

At the beginning of 1899 Professor Miyabe sent me among
some Japanese Erysiphaceae an Uncinula on Lagerstroemia Indica,
with the following note; “ U. /agerstroemiae n. sp. Appendages
very characteristic, their tips are circinate very tightly in a helicoid
manner; 78-120 X 4.54. Their number is few (3-7).

Subsequently I received from Professor McAlpine an Uncinula
on Lagerstroemia ovalifolia (“sparingly on leaves, but covering
entire inflorescence”) from the Botanic Gardens, Sydney, under
the name of U. Australiana McAlp.; with a note that this name
would shortly be published.

A comparison of the Japanese and Australian plants showed
them to be identical.

U. Australiana is somewhat intermediate between U. necator
and U. Sengokui. The latter species differs in the colorless, more
numerous, crowded appendages, distinctly stouter throughout, and
8-9 u wide in the upper half (where those of U. Australiana are
only about 6 » wide); U. necator (to the few, short-appendaged
forms of which the present species closely approaches) differs in
the always more colored appendages. In U. Australiana the color
is strictly limited to the base, not occurring above the septum ; in
all forms of U. necator the color extends upwards for a consider-
able distance. In the present species, also, it is not at all uncom-
mon to find some of the appendages of a perithecium quite color-
less. *

17. U. fraxini Miyabe mss. sp. nov. [Figs. 69-72]

Amphigenous; mycelium evanescent ; perithecia scattered,
small, 75-105 in diameter, usually 80-90 /, globose-depressed,
cells distinct, irregular in shape, averaging IO # wide * append-
ages 10-28, 114 to 2% times the diameter of the perithecium,
straight or slightly curved, simple, aseptate, thin-walled and
hyaline throughout, apex simply uncinate or sometimes distinctly
helicoid ; asci 4-7, usually 5 or 6, oblong to subglobose, occasion-
ally shortly stalked, 45-58 x 30-40 ft; Spores 8, 16-18 x
9-10 p.

*Since the above remarks were written, McAlpine (225*) has published an ac-
count of his species. It is here stated that the appendages are sometimes forked.

120 A MONOGRAPH OF THE ERYSIPHACEAE

Flost.—Fraxinus longicuspis.

Distribution.—Asi^ : Japan (Sapporo, K. Miyabe, Sept.,
1893).

Among the collection of Japanese Erysiphaceae Professor
Miyabe sent me specimens of the above plant under the mss. name
of U. fraxini. As it appears to be a distinct species hitherto un-
described, I have drawn up the above description from the mate-
rial sent. Professor Miyabe sent the following notes with the
specimens: “ U. fraximi n. sp. Perithecia 82-98 p; appendages
11-20, 170-225 y long, slender; asci (6) 30 x 45-49 D 8-
spored; spores 14-15 x 7-8 yp.”

U. fraxini may be known by the evanescent mycelium, hya-
line and thin-walled appendages, and the 8-spored asci.

18. U. Sengokui sp. nov. [Figs. 64-68]

Amphigenous ` mycelium evanescent, or subpersistent, very
thin and effused over the upper surface of the leaf; perithecia sub-
gregarious or scattered, 98-135 yw in diameter, cells 10-15 p wide;
appendages more or less crowded, 20-36, equally or (usually)
slightly exceeding the diameter of the perithecium, simple, color-
less, aseptate, or occasionally I-septate, stout, 7-8 p wide in the
lower half, not or scarcely enlarged upwards, often curved through-
out their length, hyaline above, becoming refractive and thick-
walled at the base; asci 7-12, ovate to broadly ovate, usually
shortly stalked, 48-58 x 30-34 u, spores 5-6, 18-20 x 10

Flost.—Celastrus articulatus.

Distribution.—Asia : Japan (Komaba, Tokyo, October, 1895,
K. Sengoku).

Among the collection of Erysiphaceae sent to me from Japan
by Professor Miyabe, the above species of Uncinula appears to be
new. Its affinity is undoubtedly with U. Delavayi, but the more
numerous crowded appendages not or scarcely enlarged upwards
easily distinguish the present species.

U. Sengokut, except for the absence of color in the appendages,
much resembles certain Japanese forms of U. necator.

From all forms of U. CZntonii,the present species may be dis-
tinguished by the wider base of the appendages.

MICROSPHAERA 121

MICROSPHAERA Lev. Ann. sci. nat. III. 15: 154, sub Ca/o-
cladia, & 381. 1851

Perithecia globose to globose-depressed: asci several, 2-8-
spored. Appendages not interwoven with the mycelium, branched
in a definite manner at the apex, which is usually several times
dichotomously divided, and often very ornate, rarely (JZ. astra-
galt) undivided or once dichotomous. Etym. jzxpoc, parvus, and
ogarpa, sphaera.

Distribution.—Europe, Asia, and North America; 13 species
and 6 varieties.

As a rule, the genus Microsphaera is easily known by the
much-divided and ornate apex of the appendages. In one species,
however, M. astragali, the appendages are very frequently un-
branched at the apex, and through this species Microsphaera ap-
proaches the genus Zrysiphe. From all species of Erysiphe, how-
ever, M. astragali is distinct in the long, white, assurgent, fascic-
ulate appendages. In Æ. tortilis, where the habit is somewhat
similar, the appendages are brown. At first sight it seems unnat-
ural to separate in different genera these two species, and some
authors have preferred to place M. astragali in the genus Erysiphe.
Apart from the fact, however, that the apex of the appendages in
M. astragali is sometimes definitely branched in a dichotomous
manner (so making the view possible that the unbranched condi-
tion is to be considered merely as the result of immaturity), this
species is evidently too closely allied to M. Bäumleri to be sepa-
rated generically from it; while E tortilis is similarly very close to
certain forms of EI polygoni. Magnus (231, p. 150) has lately
proposed that the characters of the two genera Microsphaera and
Erysiphe should be emended, but the definitions proposed by this
author (which involve the transference of Æ. tortilis to the genus
Microsphaera) seem to me to be less natural than that which gives
the strictly apical branching of Microsphaera as the difference of
chief generic importance. Magnus (/. c.) speaks of angularly bent
appendages as being distinctive of the genus Erysiphe ; this .char-
acter, as separating the two genera, would, however, break down
in M. euphorbiae and in many forms of £. communis. A

I have not seen sufficiently mature examples of M. umbiliei on
Cotyledon (Umbilicus) Semenovii and M. ferruginea on Verbena

122 A MONOGRAPH OF THE ERYSIPHACEAE

hybrida to be able to indicate the essential specific characters”
(probably to be found in the shape of the mature apex of the ap-
pendages). These two species, therefore, are not included in the
key ; descriptions, however, of the speeimens will be found at the
close of the account of the genus.

>

sa

m

p

Key to the Species of Microsphaera*

. Asci im en densely crowded, flaccid, about equalling the diameter
f the um.

. Mougeotii.
Asci more > mung? 2

Appendages 213-7 times the diameter of the perithecium, usually much contorted

and — bent, apical branching very irregular and lax, with the branches

ry flexuous and more or less curled. 9. euphorbiae.
Katzen Sé or short without the above characters.

. Tips of some or all of the ultimate branches of the appendages recurved. 4.

Tips not recurved. ER

. Appendages 8-12 times the diameter of the perithecium. Io Guarinonit.

Appendages less than 8 times the diameter of the perithecium.
Appendages long and flaccid.
Appendages short, not exceeding 214 times the diameter of the perithecium, not
flaccid 8.
Apex of appendages much branched, branching ornate, more or Ge close, spores
22-26 I2-I5 u. i, var. extensa
Apex less "Some more or less widely forked, or esis pei and ud.
spores 18-23 X 9- $
Appendages usually 3 2 not exceeding 517 times the diameter of the perithecium,
asci 3-7, ovate-globose, 38-48 u long. 4. alni, var. divaricata.
Appendages 2 a“ -8 times the diameter of the perithecium, asci 2-16, ovate-oblong,
45-72 u lo 4. alni, var, vaccinii.
Appendages more or less contorted, apical branching very lax and irregular
4. alni, var. die
Appendages not contorted, apical branching closer and regular. 9.
Tips of the ultimate branches of the appendages not all regularly and distinctly re-
curved. var. lonicerae.
Tips all regularly and distinctly recurved, 10.
Axis of some of the appendages not a dichotomously at the apex, but bear-
ing sets of opposite branches (Fig. 16). 4. alni, var. calocladophora.
Appendages regularly dichotomous = apex. 4. alni.
Appendages 3-7 times the diameter of the perithecium, RR nearly to aj

apex.
8. Russellü,
Appendages colorless. 12

* M. umbilici and M. ferruginea are not included in this key (see above).

MICROSPHAERA 123

m
N

. Appendages long and penicillate. 13.
Appendages not penicillate. 15.

13. Apex of appendages often undivided, or irregularly 1-2 times dichotomous.
3. as’ragali.

Apex more divided,

m
>

ee 4-6 times the diameter of the perithecium, branching diffuse and ir-
egular Bäumleri,

I3.
dree 2 = s hey times the diameter of the perithecium, apex more divided,
br 2. euonym

anching clo
15. Branching of the appendages lax, irregular. 16.
Branching closer and regular. 17.

m
fo.)

i er 2-4 times the diameter of the perithecium, not contorted, ultimate
nches long, forming a narrow fork. . diffusa.
hiemes I-2 times the diameter of the perithecium, more or less contorted,
branching more irregular, with short ultimate branches. 4. alni, var. ludens.

-
SI

. Apex of appendages with very short primary and secondary branches more or less
digitate (Fig. 34). grossulariae.
Apex primary and secondary branches longer.

18. Apex with short, widely spreading, usually curved ultimate branches.
4. alni, var. lonicerae.

Apex with long, straight ultimate branches, not widely spreading. I. derberidis.

1. M. BERBERIDIS (DC.) Lév. [Figs. 40, 41]

Erysiphe berberidis DC. Fl. Fr. 2: 275. 1805; Tul. Sek
Fung. Carp. 1: 204. pl. 5.f. r. 1861; de Bary, Beitr. Morph.
Phys. Pilz. 1: § xiii. 51. | 1870.

Alphitomorpha penicillata, var. berberidis Wallr. Berl. Ges. Nat.
Freund. Verh. 1: 40. 1819; Wallr. Fl. Crypt. Germ. 2: 754.
1833.

Erysibe berberidis DC.; Gray, Nat. Arr. Brit. Pl.1:590. 1821.

E. divaricata B Schlecht. Fl. Berol. 2: 169. 1824.

E. penicillata, var. berberidis Lk.; Willd. Sp. PLO: 114. 1824;
Rabenh. Deutschl. Krypt. Fl. 1: 236. 1844.

Erysiphe penicillata, var. berberidis Fr. Syst. Myc. 3: 244.
1829; Duby, Bot. Gall. 2: 871. 1830.

E. penicillata Lk. ; Johnst. Fl. Berw. 2: 143. 1831; Berk.;
Sm. Engl. Fl. 5: 327 (partim). 1836.

Erysibe divaricata Rabenh. Fl. Lusat. 2: 420 (partim). 1840.

Microsphaera berberidis Lev. Ann. sci. nat. III. I5: 159. 2.
Zo f. 28 (sub cea 1851; Cooke, Micr. Fung. 219. A.

124 A MONOGRAPH OF THE ERYSIPHACEAE

II. f. 229—232. 1865; Cooke, Handb. Brit. Fung. 2: 649.
1871; Sacc. Syll Fung. 1: 13. 1882; Wint.; Rabenh. Krypt.
Fl. Deutschl. 17: 36. 1884; Karst. Act. Soc. Faun. Flor. Fenn.
2:91. 1885 ; Schroet.; Cohn’s Krypt. Fl. Schles. 3: 243. 1893 ;
Jacz. Bull. Herb. Boiss. 4: 746. 1896; Oudem. Rev. Champ.
Pays.-Bas. 2: 92. 1897.

Calocladia berberidis Lev. Dietr. Blick. Crypt. Ostseeprov. 336.
1856; Karst. Myc. Fenn. 2: 196. 1873.

Podosphaera berberidis Lev. ; Quél. Champ. Jur. Vosg. 3: 106

Exsicc.: Rab.-Wint.-Patzsch. Fung. Eur. 3855; Rab. Fung.
Eur. 555, 2318; Rehm. Ascom. 499; Fckl. Fung. Rhen. 693;
de Thim. Fung. austr. 137; Syd. Myc. March. 246; Roumeg.
Fung. Select. Gall. Exsicc. 159; Oudem. Fung. Neerl. Exsicc.
153; Rab. Herb. Myc. ed. 2, 459; Cooke, Fung. Brit. Exsicc.
95, ed. sec. 283; de Thim. Myc. univ. 1838; Kunze. Fung.
select. exsicc. 320; Westend. Herb. Crypt. Belg. 738; Desmaz.
PL Cr. Fr éd r ser. & 819; Vize Pung. Bnt 93; *Erikss.
Fung. par. scand. 143.

Amphigenous ` mycelium evanescent, or sometimes sub-per-
sistent in irregular patches, or very thinly effused over the whole
surface of the leaf; perithecia usually scattered, occasionally more
or less densely gregarious, 90-125 & in diameter, cells 10-15 A
wide; appendages 5-20, 114—214 times the diameter of the peri-
thecium, colorless, thin-walled above, becoming thick-walled in
the lower half when mature, aseptate, smooth, apex regularly 4
times dichotomously branched, branching rather close, branches of
the last order more or less parallel, never widely spreading, tips of
ultimate branches not recurved; asci 4-9, ovate-oblong, very
shortly stalked, 48-56 X 26-32 #; spores 3-6, usually 4, 18-22 x
rılp

Flost.—B. aquifolium, B. vulgaris.

Distribution —EUROPE: Britain, France, Belgium, Nether-
lands, Germany, Switzerland, Italy (307), Austria-Hungary,
Servia (318), Norway, Sweden, Finland (192), Russia.

Asia :— Cyprus, Transcaucasia (338), Turkestan, Japan.

Somewhat intermediate between JM. grossulariae and M. alni,
var. lonicerae. The apex of the appendages is regularly 4 times
divided, and the straight ultimate branches do not spread widely,
but lie more or less parallel to one another, in this respect some-

MICROSPHAERA 125
what recalling those of M. grossulariae. In M. berberidis, how-
ever, the branches of the first and second orders are of about equal
length to the others, so that the manner of branching of the whole
apex differs conspicuously from that of M. grossulariae, where the
primary and secondary branches are extremely short (cf. Figs.
34, 35, and 40, 41). M. grossulariae has, also, shorter appendages
and slightly larger spores.

M. alni, var. lonicerae differs from M. berberidis in the spread-
ing ultimate branches of the apex of the appendages, which occa-
sionally have recurved tips, the usually fewer asci, etc.

At the beginning of last November my attention was directed
to some bushes of Berberis (Mahonia) aquifolium in a shrubbery
near Reigate, Surrey, England, which were, chiefly on the young
shoots, more or less white with the mycelium of M. berberidis.
The perithecia were densely gregarious on both sides of the leaf,
and agreed in all characters with examples of the species on the
usual host, 4. vulgaris. This occurrence on an evergreen species
of Berberis is very interesting, as hitherto in its wide range in Eu-
rope, and in Asia, the species has been supposed to be absolutely
confined to a single species or host-plant, viz. Berberis vulgaris.

The Japanese example of the present species was sent to me
by Prof. Miyabe, and agrees perfectly with the European plant,
and the same is the case with beautiful specimens sent by Prof.
Gennardius from Cyprus.

2. M. EvoNvur (DC.) Sacc.

Erysiphe euonymi DC. Fl. Fr. 6: 105. 1815; Duby, Bot.
Gall. 2:871. 1830.

Alphitomorpha comata Wallr. Berl. Ges. Nat. Freund. Verh. 1:
40. 1819; Wallr. Fl. Crypt. Germ. 2: 757. 1833.

A. euonymi Wallr. Ann. Well. Ges. 4: 245. 1819.

Erysibe comata (Wallr.) Ficin. Schub. Fl. Gegend. Dresd. 2:
xix. 1823; Lk. in Willd. Sp. Pl. 6: 114. 1824; Rabenh.
Deutschl. Krypt. Fl. 1: 231. 1844.

Erysiphe penicillata, var. cuonymi Fr. Syst. Myc. 3: 244.
1829.

E. comata Lk. ; Secret. Mycogr. Suisse, 3: 653. 1833.
Microsphaera comata Lev. Ann. Sci. Nat. III. 15: 157. fV. 9.

126 A MONOGRAPH OF THE ERYSIPHACEAE

23 (sub Calocladia). 1851; Cooke, Handb. Brit. Fung, 2:
649. 1871.

Calocladia comata Lév. ; Dietr. Blick. Crypt. Ostseeprov. 336.
1856.
Podosphaera comata (Lev.) Quel. Cham, Jur. Vosg. 3: 106
1875.
Microsphaera euonymi (DC.) Sacc: Syll. Fung. 1: 11. 1882;
Wint.; Rabenh. Krypt. Fl. Deutschl. 17: 37. 1884; Schroet.;
Cohn's Krypt. Fl. Schles. 3: 242. 1893; Jacz. Bull. l'Herb.
Boiss. 4: 749. 1896; Oudem. Rév. Champ. Pays.-Bas. 2: 9o.
1897.

Exsicc.: de Thuem. Fung. austr. 1238 ; Sacc. Myc. Ven. 892;
Syd. Myc. March. 199, *4335, *4336; Fckl. Fung. Rhen. 692;
Cooke, Fung. Brit. Exsicc. 94 ; Rab. Fung. Eur. 438, 1324, 2319;
Rehm. Ascom. 248; Roumeg. Fung. Gall. exsicc. 3224; Vize.
Fung. Brit. 196 ; *de Thuem. Myc. univ. 847 ; *Kneiff. & Hart.
Pl. Crypt. Bad. 55 ; Wint. Fung. Helvet. Supp. 84 (in Herb. Earle).

Usually hypophyllous, very rarely amphigenous ; mycelium
evanescent or nearly so; perithecia more or less densely gre-
garious, 85—138 y in diameter, cells obscure, about 10 p wide ; ap-
pendages 6-14, 217—571; times the diameter of the perithecium,
flaccid, colorless, thin-walled above, becoming thick-walled to-
wards the base, aseptate, smooth, fasciculate and forming a flaccid
** pencil " which lies on the surface of the leaf, apex variously 3—5
times dichotomously, or sub-dichotomously, branched, branching
variable, lax or close, tips of ultimate branches usually straight ; asci
3-7, ovate to broadly ovate, 50-60 x 30-38 p, with a short stalk ;
spores 3-5, 20-23 x 10-12 yp.

Hosts.—Euonymus Europaeus, E. verrucosus (294).

Distribution —EUROPE : Britain, France, Belgium (47) (209),
Netherlands (263), Germany, Switzerland, Italy, Austria-Hungary,
Denmark, Finland, Russia.

A well-characterized species in the fasciculate habit of the
long appendages (which form when mature a flaccid “pencil ”),
and the much-branched apex.

In other characters M. euonymi is very variable, especially as
regards the manner of branching of the apex of the appendages.
The branching is sometimes somewhat lax, and the apex is 3
times dichotomously divided, with the primary and secondary
branches more or less recurved, often strongly so, and even the

MICROSPHAERA 127

tips of the ultimate branches show, in this form, a slight tendency
to become recurved; the specimen in de Thüm. Fung. austr.
1238 illustrates this form. More frequently, however, the apex
is closely 4-5 times branched, when the dichotomous arrange-
ment often ceases at the branches of the third order, and the subse-
quent branches are irregularly arranged, short, often very flexuous
and lying in different planes, with the tips not at all recurved, e.
g., the specimen in Rabenh. Fung. Eur. 1324. In other speci-
mens, again, the branching is dense, the primary branches short,
and the subsequent ones long, straight and narrow.

M. euonymi is confined to Europe ; the record of its occurrence
in California “on Zuonymus” by Harkness and Moore (159) is
doubtless an error.

3. M. astracarı (DC.) Trev. [Figs. 47-51]

Erysiphe astragali DC. Fl. Fr. 6: 105. 1815; Duby, Bot.
Gall 2: 871. 1830; Tul. Sel. Fung. Carp I: 200. M. 2.J. £
1861; de Bary, Beitr. Morph. Phys. Pilz. 1: $ xiii. 51. 1870.

Alphitomorpha holosericea Wallr. Berl. Ges. Nat. Freund. Verh.

41: ISIQ.

A. astragali Wallr. Ann. Wett. Ges. 4: 244. 1819

Erysibe holosericea (astragali) Lk: Willd. Sp. Pl. 0: 215
1824; Rabenh. Deutschl. Krypt. Fl. ı: 231. 1844.

Erysiphe communis, & E. holoserieca Fr. Syst. Myc. 3: 240.
1829.

Alphitomorpha sericea Wallr. Fl. Crypt. Germ. 2: 757. 1833.

Microsphaera holosericea Lév. Ann. Sci. Nat. III. 15: 159. A.
9. f. 27 (sub Calocladia). 1851.

M. astragali (DC.) Trev., Spighe e Paglie, 1: 39. 1853 (fide
Sacc.); Sacc. Syll. Fung. 1: 12. 1882; Wint.; Rabenh. Krypt.
Fl Deutschl. 1?: 35. 1884; Jacz. Bull. l'Herb. Boiss. 4: 746.
1896 ; Oudem. Rev. Champ. Pays.-Bas. 2: 91. 1897.

Calocladia holosericea Lév. Dietr. Blick. Crypt. er
336. 1856; Fckl. Symb. Myc. 82. 1869-70.

Erysibe astragali Schroet.; Cohn’s Krypt. Fl. Schles. 3:
1893.

Exsicc.: Desmaz. Pl. Cr. Fr. ed. 1, ser. 1, 924,*ed. 2, ser. I, 224,
Rab. Fung. Eur. 439, 2413; Westend. Herb. Crypt. Belg. 1059;

128 A MONOGRAPH OF THE ERYSIPHACEAE

Roumeg. Fung. Gall. Exsicc. 1164, 3141; de Thüm. Fung. austr.
459; Fckl. Fung. Rhen. 694; Sacc. Myc. Ven. 148; Rab. Herb.
myc. ed. 2, 469; Oudem. Fung. Neerl. Exsicc. 159; Erb. Critt.
Ital. 144, *193; Rehm. Ascom: 448; * Syd. Myc. March. 979;
* Romell. Fung. exsicc. praes. scand. 62.

Hypophyllous, or amphigenous ; mycelium evanescent, or
sometimes faintly persistent ; perithecia usually densely gregarious,
but sometimes scattered, globose-depressed, 95-146 x» in diameter,
cells small, about 10 & wide, appendages 5-18, 4-10 times the
diameter of the perithecium, smooth, colorless and aseptate (some-
times brown towards the base, and then usually septate), hyaline
above, becoming thick-walled and refractive in the lower half when
mature, flexuous, sub-flaccid, penicillate, apex frequently un-
branched (? immature) or once or twice dichotomously branched,
branching lax and vague, primary branches usually long, and
more or less recurved, tips of ultimate branches not recurved ; asci
5-12, ovate-oblong to broadly-ovate, 52—68 * 3 p usually
stalked ; spores 3-6, usually 4, 20-23 x 10-1

Hosts —Astragalus Cicer (164*) (384), 4. i pU ıyllos, A.
onobrychis (390).

Distribution. —EUROPE : Britain, France, Belgium, Netherlands,
Germany, Switzerland, Italy, Austria-Hungary, Denmark, Nor-
way, Sweden, Russia.

M. astragali is related M. Bäumleri and M. euonymi in the
flaccid penicillate appendages, but differs from both species in the
apex of the appendages being less branched. In the present
species the very long and flexuous appendages, which are about
6 » wide, are thick-walled and shining in their lower half, and
whether seen singly under the microscope or in dense clusters on
the leaf, present a shining silky appearance which makes the old
specific name of holosericea very appropriate. The apical branch-
ing of the appendages is extremely ill-defined, in fact, there are
usually only two or three appendages in any perithecium which
show any signs of branching at all. I have once seen the apex
feebly 3-times dichotomous, rarely it is twice dichotomous, but is
usually (when branched at all) only once forked, as is generally
described.

Several authors, on account of this slight branching of the ap-
pendages, have placed the present species in Erysiphe ; the apical
branching, however, when present, is regularly dichotomous and

MICROSPHAERA 129

definite, and unlike that found in Zrysiphe, and the proper position
of the present plant is certainly in Microsphaera, to one species of
which— 7. Baumleri—it shows a close relationship.

M. astragali is confined to Europe ; the plants referred to this
species from North America all belong (as far as I have seen) to
M. euphorbiae. This is the case with the specimen “ M. holoseri-
cea Lév., on leaves of Astragalus Cooperi, Buffalo, N. Y. (C.H.
Peck, n. 198)," recorded by Cooke and Peck in the Journal of
Botany (91), and mentioned in Saccardo's Sylloge, 1: 12; also
with the specimen named “ M. holosericea” on an unnamed host-
plant (probably Astragalus Drummondi), n. 1572, Flora of Col-
orado, Colorado Springs (5500 ft.), 1879 (M. E. Jones); and with
other examples.

Massalongo (237, p. 127) has recorded “ M. astragali f
cytisi" on “Cytisus alpinus (vel C. Laburnum)." Specimens (now
in the Kew Herbarium) kindly sent to me by this author prove to
belong to M. Guarinonit.

Winter records M. astragali on Astragalus virgatus, but the
fungus so-named on this host in the Exsiccati quoted by this
author (de Thuem. Fung. austr. 1237) is Erysiphe polygoni.

4. M. ani (Wallr.). [Figs. 1-14]

Alphitomorpha penicillata, var. alni Wallr. Berl. Ges. Nat.
Freund. Verh. 1: 40 (syn. excl.). 1819.

A. alni Wallr. Ann. Wett. Ges. 4: 237 (syn. excl) 1819.

A. penicillata, var. rhamni cathartici Schlecht. Berl. Ges. Nat.
Freund. Verh. 1: 49. 1819.

Erysibe penicillata Lk. ; Willd. Sp. Pl. 6: 113 (excl. vars.
grossulariae and berberidis, and syn. E aim DC.). 1824; Rabenh.
Deutschl. Krypt. Fl. 1: 236 (partim). 1844.

Erysiphe penicillata Fr. Syst. Myc. 3: 244 (partim). 1829;
Duby, Bot. Gall. 2: 871 (partim). 1830; Berk.; Sm. Engl. Fl.
5: 327 (partim). 1836.

E. viburni Duby, Bot. Gall. 2: 872. 1830.

Alphitomorpha penicillata Wallr. Fi. Crypt. Germ. 2: 754 (par-
tim). 1833.

Erysiphe densissima Schwein. Syn. Fung. Am. Bor. 269. 1834.

130 A MONOGRAPH OF THE ERYSIPHACEAE

E. ceanothi Schwein. Syn. Fung. Am. Bor. 269. 1834; Sacc.
Syl, Fung. 1: 22 1882.

E. viburni Schwein. Syn. Fung. Am. Bor. 269. 1834; Sacc.
Syll Fang: 1.1921... 1982,

E. syringae Schwein. Syn. Fung. Am. Bor. 270. 1834; Sacc.
Syl Funp. T: 201... 1582

E. quercinum Schwein. Syn. Fung. Am. Bor. 270. 1834;
Sack. Sylke Fungi: 22. 1882.

Microsphaera Hedwigit Lev. Ann. sci. nat. III. 15: 155. a
8. f. 19 (sub Calocladia). 1851; Cooke, Mier, Fung. 219. 1865;
Cooke, Handb. Brit. Fung. 2: 648. f. 376. 1871; Sace: Syll.
Fung. 1: 11. 1882; Oudem. Rév. Champ. Pays.-Bas. 2: 9o.
1897.

M. penicillata Lév. Ann. sci. nat. III. 15: 153. pl. 8. f. 21
(sub Calocladia) (excl. syn. E. alni DC. & Sclerot. Erysiphe, var.
alnea Schleich). 1851; Cooke, Mier, Fung. 219. AX. rz. f. 234.
1865; Cooke, Handb. Brit. Fung. 2: 649. 1871; Sacc. Syll.
Fung. I: 13. 1882; Oudem. Rév. Champ. Pays.-Bas. 2: 92
(excl. syn. E. alni DCL 1897.

M. Friesti Lev. Ann. sci. nat. III. 15: 156. pl. 8. f. 20 (sub
Calocladia) (excl. syn.). 1851; Sacc. Syll. Fung. 1: 13. 1882.

Calocladia Friesii Lev. Dietr. Blick. Crypt. Ostseeprov. 337.
1856.

Erysiphe alni Tul. Sel. Fung. Carp. 1 : 203. pl. 2. f. 5-7 (excl.
syn. E almi DC.). 1861.

Calocladia Hedwigi Lév. Fckl. Symb. Myc. 81. 1869-70.

C. penicillata Lév. ; Fckl. Symb. Myc. 81. 1869-70; Karst.
Myc. Fenn: 2: 196. 1873.

Microsphaera pulchra Cooke & Peck, Journ. of Bot. II. 1 : 12.
1872; Peck, Reg. Rep. 35: 95... 1873; Sace 5yll. Pung, 1: 12.
1882.

M. Friesü, var. syringae Cooke & Peck, Journ. of Bot. II. 1:
12. 1872.

M. Friesti, var. vaccinit Cooke & Peck, Journ. of Bot. II. 1:
12. 18073.

M. semitosta Berk. & Curt. ex Cooke & Peck, Journ. of Bot. II.
1:13. 1872;Berk. & Curt. Grevillea, 4: 160. 1876 ; Sacc. Syll.
Fung. 1: 11. 1882; Burr. & Earle, Bull. Ill. State Lab. Nat.

MICROSPHAERA 131

Hist. 2: 415. 1887; Atkins. Journ. Elisha Mitch. Sci. Soc. 7 : 69.
pl. 1. f. 12-14. 1891; Burr. ; Ell. & Everh. N. Amer. Pyren.
25. 1892.

M. sparsa E. C. Howe; Cooke & Peck, Journ. of Bot. Ii. 1:
i25 ' ERR

M. penicillata, var. alni Cooke E Peck, Journ. of Bot. II. 1:
HH. EE

M. densissima ( Schwein.) Cooke & Peck, Journ. of Bot. II. 1:
171. 1872; Peck, Reg. Rep. 26: 80. 1874; Sacc. Syll. Fung.
1. 152. 188m

M. menispermi E. C. Howe, Bull. Torr. Club, 8:1. 1995455
Sacc. Syll Fung. 9: 369. 1891; Burr. ; Ell. & Everh. N. Amer.
Pyreti; 22..-:4892,

M. platani E. C. Howe, Bull. Torr. Club, 5: 4. 1874; Sacc.
Syll. Fung. 9: 369. 1891.

M. viburni E. C. Howe, Bull Torr. Club, 5: 43. 1874 ;
Sace Syll. Fung. 9: 369. 1891.

Podosphaera Hedwigit (Lév.) Quél. Champ. Jur. Vosg. 3:
106. 1875.

P. penicillata (Lév.) Quel. Champ. Jur. Vosg. 3: 106. 1875.

Microsphaera abbreviata Peck, Reg. Rep. 28: 64. pl. 2. f. 4,
51876 ; Sate: Syll. Fung. £: Ii. -1882

JM. Ravenelü Berk. Grevillea, 4: 160. 1876; Sacc. Syll.
Fung. 1: 14. 1882; Burr. & Earle, Bull. Ill. State Lab. Nat.
Hist. 2: 420. f. 8. 1887; Burr. ; Ell. & Everh. N. Amer. Pyren.
23. 1892.

M. erineophila Peck, Bull. Torr. Club, 10: 75. 1883 ; Burr.
& Earle, Bull. Ill. State Lab. Nat. Hist. 2: 419. 1887; Sacc.
Syll. Fung. Addit. ad Vols. L-IV.: 2. 1886; and 9: 368. 1891;
Burr. ; Ell. & Everh. N. Amer. Pyren. 29. 1892.

M. alni (DC.) Wint. ; Rabenh. Krypt. Fl. Deutschl. 1°: 38.
1884; Karst. Act. Soc. Faun. Fl. Fenn. 2: 92 (excl. syn. Z. aimi
DC.) 1885; Burr. & Earle, Bull. Ill. State Lab. Nat. Hist.
2: 421 (excl. syn. E alni and M. Van Bruntiana E. C. Howe).
1887; Atkins. Journ. Elisha Mitch. Sci. Soc. 7: 71. 1891;
Burr.; Ell. & Everh. N. Amer. Pyren. 27 (excl. syn. Æ abri
DC. and E betulae DCL 1892; Schroet. ; Cohn's Krypt. Fl.
Schles. 3: 244. 1893; Jacz. Bull. l'Herb. Boiss. 4: 748 (excl.
syn. E. a/ni). 1896. ` -

183 A MONOGRAPH OF THE ERYSIPHACEAE

M. nemopanthis Peck, Reg. Rep. 38: 102. 1886; Sacc.
Syll. Fung. Addit. ad Vols. L-IV.: 2. 1886; and 9: 368.
189r.

M. quercina (Schwein.) Burr.; Burr. & Earle, Bull Ill.
State Lab. Nat. Hist. 2: 424 (partim). 1887; Atkins. Journ.
Elisha Mitch. Sci. Soc. 7: 72. 1891; Burr. ; Ell. & Everh. N.
Amer. Pyren. 28 (partim). 1892.

M. quercina, var. abbreviata Atkins. Journ. Elisha Mitch. Sci.
293... Oge

Exsıcc.: Syd. Myc. March *247, 657, 2662, *3672, *3720,
* 3721, *3947, *4334, *4433; Fckl. Fung. Rhen. 690, 691, 695 ;
Lib. Pl Crypt. Ard. fasc. 1, 81; Rab. Fung. Eur. 437, 2031,
*2032; Sacc. Myc. Ven. 147, 618, 619, 893 ; Desmaz. Pl. Cr.
Pe oth r wer d 025 022 JA. & B. gái, "ed. 2, ser. t, 22t,
222, 223; de Thüm. Fung. austr. 138, 139; Baxt. Stirp. Crypt.
Oxon.; Rehm. Ascom. 299, 446, 599, 848; Bri. & Cav. Fung.
par. 40; Cooke Fung. Brit. exsicc. 218; de Thuem. Myc. univ.
56, 155, 557, 558, 958, 2054, 2055; Westend. Herb. Crypt.
Belg. 112; and 831 (in Herb. Jard. bot. Bruxelles); Kunze.
Fung. select. exsicc. 237, 318, 576; Rab. Herb. Myc. ed. 2, 474;
and 462 sub Zrysibe guttata, var. betulae; Ell. N. Amer. Fung.
428, 432, 659, 767, 770, 1325; Ell. & Everh. N. Amer. Fung.
660, 1539, 1945; and 559 sub M. Dubyi; sec. ser. 1783, 3008;
Rab.-Wint.-Pazsch. Fung. Eur. 3953; Rav. Fung. Amer. Exsicc.
87, 626, 627; Rav. Fung. Car. Exsicc. 67, 68; Vize. Fung. Brit.
198, 473; Roumeg. Fung. Gall. Exsicc. 3650; Rab.-Wint. Fung.
Eur. 3044, 3245, 3744; Roumeg. Fung. select. exsicc. 4563 ;
SEIL & Everh. Fung. Columb. 111, 508; *Wartm. & Wint.
Schweiz. Crypt. 825 ; *Wartm. & Schenk, Schweiz. Krypt. 424;
*Seym. & Earle, Econ. Fung. 45, 124, 176, 183, 187; Wint.
Fung. Helvet. Supp. 85 (in Herb. Earle); Klotzsch. Herb. Myc.
178 (in Herb. Upsala Mus.); Schleich. cent. exsicc. 68 (in Herb.
De Candolle).

Amphigenous ; mycelium evanescent, or persistent, and then
thin and usually more or less effused over the surface of the leaf,
or rarely (as sometimes on Quercus, Alnus, Viburnum and
Vaccinium) forming definite, more or less rounded patches ; peri-
thecia scattered or more or less densely gregarious, globose de-
pressed, very variable in size, usually small, 66-110 # in diameter,

>

MICROSPHAERA 133

sometimes 110-135 np. cells 10-15 p wide, rarely 15-18 p; ap
pendages very variable in number and length, 4-26, %-2 % times
the diameter of the perithecium, usually about 1 7 times diameter,
more or less rigid, colorless throughout or amber-brown at base,
or rarely colored to the commencement of the apical branching,
smooth, or occasionally rough toward the base, which usually be-
comes thick-walled, aseptate or occasionally 1-2-septate toward
the base, apex variously but always more or less closely, 3-6
times dichotomously branched, tips of ultimate branches regularly

and distinctly recurved ` asci 3-8, ovate to ovate globose, 42-70

X 32-50, usually but not always shortly stalked; spores 4-8,
18-23 X 10-121.

Hosts — Alnus glutinosa, A. incana and var. virescens, A, mar-
ima, A. rubra, A. serrulata, A. viridis, Apios tuberosa, Astragalus
adsurgens (60), Betula alba, B. lenta, B. lutea, B. pumila (60)
(97), Carpinus Americana (60), Carya alba, C. sulcata, Castanea
dentata (249), C. sativa and vars. Americana and Japonica, Ceano-
thus Americanus, Celastrus scandens (60), Cephalanthus occidentalis,
Cornus alternifolia, C. Amonum (60), C. macrophylla, C. stolo-
nifera (363), Corylus Americana, C. rostrata and var. Mandshurica,
Euonymus atropurpureus, Fagus atropunicea (249), F. ferruginea,
Forestiera acuminata, Gleditschia triacanthos, Gymnocladus sp.,
lex decidua, I. mollis (371), I. verticillata (97), Juglans cinerea, J-
nigra, Lathyrus ochroleucus, L. palustris (61), L. pratensis, L. veno-
sus, Ligustrum medium, Lonicera flava, L. glauca, L. glaucescens,
L. hirsuta (60), Z. involucrata, L. oblongifolia, L. parviflora, L. sem-
perivirens, L. Sullivantit (60), Lyonia paniculata (60), Menispermum
Canadense, Nemopanthus fascicularis, Ostrya Virginica, Picrasma
quassioides, Platanus occidentalis, Quercus alba, Q. aquatica, Q. bi-
color, Q. bicolor x macrocarpa, Q. bicolor x Michauxn, Q. Catesbaet,
Q. coccinea and var. tinctoria, Q. crispula, O. dentata, Q. falcata,
Q. imbricaria, Q. lyrata, Q. macrocarpa, Q. nigra, Q. obtusiloba,
QO. Phellos, ©. Prinus, Q. Robur, Q. rubra, Rhamnus cathartica,
Rhododendron nudiflorum, Sambucus Canadensis ( 122), (265),
Schizandra Chinensis, Syringa Amurensis, var. Japonica, S. Persica
(269), S. vulgaris, Tecoma radicans, Ulmus Americana, Vaccinium
corymbosum, Viburnum acerifolium, V. dentatum, V. Lantana, V.
Lentago, V. Opulus, V. prunifolium, V. pubescens, V. Tinus (246),
Vicia Americana and var. ‚linearis, Zelkova acuminata [Populus
Zranilidentata].

134 A MONOGRAPH OF THE ERYSIPHACEAE

Distribution. —EvRoPE: Britain, France, Belgium, Nether-
lands, Germany, Switzerland, Italy, Austria-Hungary, Denmark,
Norway, Sweden, Russia.

Asta: Transcaucasia (338), Japan.

NoRTH AMERICA: United States—Maine, Vermont (153),
Massachusetts, Connecticut, New York, Pennsylvania, Maryland,
New Jersey, Delaware, West Virginia, North and South Carolina,
Ohio, Michigan, Indiana, Alabama, Illinois, Mississippi, Wisconsin,
Missouri, Iowa, Minnesota, South Dakota, Kansas, Montana,
Wyoming, Colorado, California (159), Washington. Canada, New
Brunswick, Ontario, Manitoba.

The most variable species of the Erysiphaceae. Starting with
the forms described as M. Hedwigit, M. Friesii and M. penicillata
by Léveillé, examination of authentic specimens in the Kew Her-
barium shows conclusively that these represent but a single species.
The specific character on which Léveillé relied for the separation
of Hedwigit, Friesii and penicillata was the presence of respectively `
4, 6 and 8 spores in the ascus. Dealing only with the authentic
specimens from Léveillé's Herbarium, we find up to 7 spores in
specimens named Hedwigi, 4-7 spores in Pies, and 4-8 spores
in penicillata. It is quite clear, therefore, that the species under
consideration must be allowed a range of 4-8 spores. We may
note, too, that in these same specimens, the perithecia vary in
diameter from 68-110 p.

Winter (394) has already pointed out that these three species
of Léveillé's must be united, and has adopted as tlie oldest name
for the plant Zrysiphe alni DC., calling the present species, there-
fore, M. a/ni (DC.) Wint. Unfortunately, this identification is in-
correct, as De Candolle's Æ. alni is really the species now known
as Phyllactinia corylea. De Candolle described his species as fol-
lows (Syn. Pl. Fl. Gall. p. 57): “ Hypophylla, filamentis plurimis
expansis longissimis liberis," and added as a synonym “Sclerotium
Erysiphe alnea Schl. cent. exs. nr. 68." De Candolle added in
Lam. Enc. Meth. (Bot.) 8: 219, these remarks, “ Il y a beaucoup
de rapport entre cette espèce et la précédente [Arysiphe coryli
Hedw. = Phyllactinia corylea] ; elle en diffère par les filaments de sa
base, beaucoup plus longs, plus étalés et en plus grand nombre."
This description leaves no doubt that examples of Phyllactinia

MICROSPHAERA 135

corylea on Alnus were under observation. M. Casimir de Candolle
has kindly sent me the example of ‘Schleich. cent. exsicc. n.
68" from De Candolle’s herbarium, and the fungus proves to be
Phyllactinia corylea.

Wallroth was apparently the first to confuse the present spe-
cies of Microsphaera with De Candolle’s plant, as this author gives to
his Alphitomorpha penicillata, var. alni, which from the description
we recognize as a Microsphaera ; the synonym Erysiphe alni DC.
Fortunately, therefore, we can still, by adopting Wallroth’s varietal
name, retain the specific name alni for the present species.

Returning to the study of the various forms of M. alni (Wallr.)
we find that in American examples the perithecia, which are some-
times (e. g., in certain specimens on Corylus Americana) only 66 n
in diameter may reach to as much as 130 in diameter on other
hosts. In American material, further, the appendages gradually
become longer, reaching in rare cases a length of 2% times the
diameter of the perithecium. Also, the branching of the apex of
the appendages tends gradually to become more elaborate, reach-
ing its height in the forms on Cornus and Quercus which have
been described as M. pulchra, M. densissima, and M. quercina.

M. pulchra has already been united by American mycologists
to M. alni, and there can be no doubt of the correctness of this
arrangement. This plant on Cornus alternifolia is nevertheless one
of the most striking of the American forms, and in its extreme state,
with the perithecia 130 a in diameter, with 17-22 appendages 114
to twice the diameter, and especially the very ornate apical branch-
ing, producing a more or less square outline (Figs. 4—6) seems at
first almost worthy of separation. There is, however, no diffi-
culty with sufficient material at hand, in seeing that « M. pulchra `
is too intimately connected with many. American forms of M. alni.
I have seen specimens on Alnus incana from New York with peri-
thecia averaging 120 pin diameter, with 20-26 appendages, not
much exceeding the diameter of the perithecium, but with the
apical branching very similar to that of “M. pulchra.” Moreover,
the large sized perithecia and numerous appendages are not invari-
ably found in “M. pulchra” itself; in the type specimen there
occur side by side with perithecia 130 nm in diameter, with 16-20
appendages, smaller ones (containing ripe asci) 9o # in diameter,
with only 6 appendages.

136 A MONOGRAPH OF THE ERYSIPHACEAE

M. quercina (Schwein.) Burr. is maintained as a species by
Burrill in Ellis and Everhart’s N. Amer. Pyrenomycetes. This
species on American oaks has been built up out of Erysiphe quer-
cina Schwein., Microsphaera extensa Cooke and Peck, and M. ab-
breviata Peck.

M. abbreviata Peck, occurring on certain oaks, was described
(279) as “ allied to M. Hedwigii [= M. a/ni], from which it is sep-
arated because of the short scabrous appendages." These char-
acters prove wholly insufficient to distinguish this form, and “ M.
abbreviata" may safely be considered a synonym of M. a/ui.

AM. extensa Cooke and Peck, however, is a marked plant in its
typical form with the long flaccid appendages, and althougn con-
nected by intermediates with M. alni, I consider it is worthy of
being separated as a variety.

M. quercina (Schwein.) Burr. has always been recognized as a
somewhat unsatisfactory species. Burrill, e. g., says (60, p. 29),
“ It must be acknowledged that it is well nigh impossible to dis-
tinguish some forms referred to M. alni from certain specimens
placed under M. quercina, except by reference to the host-plants."'
By separating M. extensa as a variety, and uniting the other forms
on oaks with MM. alni, from which they do not differ except in
occasionally showing a slightly more elaborately branched apex,
we get a more natural arrangement of the American forms of
Microsphaera on Quercus.

AM. densissima (Schwein.) Cooke and Peck (91) must certainly
be referred to M. alni. The plant is thus described : * Hyphasma
very dense, between filamentose and himantioid, indefinite suborbi-
cular patches %-2 in. broad, somewhat radiating at the margin,
persistent ; concepticles few, scattered ; appendages 6-10, sporangia
4-8 ; sporidia 8. Remarkable for the definite orbicular patches of
mycelium. On leaves of Quercus." In Cooke and Peck's type
the persistent mycelium forms definite suborbicular spots on which
the perithecia are seated; in all other respects the characters
shown are those of ordinary M. alni. Curiously in the specimen
of “ Erysiphe densissima’” from Schweinitz's herbarium, in Berke-
ley's herbarium at Kew (which is identical in other respects with
Cooke and Peck's specimen, and is accepted as the same species
by Cooke), the mycelium is completely evanescent. It is quite

MICROSPHAERA ' 48%

certain that in M. alni, as in many species of the Erysiphaceae, the
mycelial characters are too variable to be of any systematic value.
In an interesting series of specimens in the Kew Herbarium, from
the herbarium of W. R. Gerard the mycelium on some leaves is
persistent in suborbicular patches, on other leaves subpersistent
and more or less effused, finally on others the mycelium is wholly
evanescent and the perithecia are seated on the discolored patches
of the leaf. Occasionally, too, on other hosts than Quercus, M.
alni shows a persistent mycelium forming definite spots as is seen in
certain specimens on Viburnum, Alnus, etc. The definite subor-
bicular patches of persistent mycelium could not therefore, even if
constant, be considered as distinctive of “ M. denszssima."

Howe’s plant, originally published as M. sparsa in the Journal
of Botany (91) and later (168) as M. viburni (Schwein.) agrees
with specimens of Zryszphe viburmi Schwein. from Schweinitz's
herbarium, and does not differ from ordinary M. alni. The same
is the case with Æ. ceanothi Schwein., E. syringae Schwein., M.
platani Howe, and M. nemopanthis Peck.

M. Ravenelii Berk. (on Gleditschia triacanthos), since its publi-
cation in Grevillea in 1876, has been kept distinct as a species by
all authors, but neither in the type-specimen at Kew, nor in the
numerous specimens so-named in American collections that I have
examined, can I find any characters separating it from M. alni.
` Often the apex of the appendages is only 3 times dichotomously
branched (the tips of the ultimate branches are always regularly
recurved) and the plant is then identical with the usual European
forms of JZ alni ; frequently, however, the apical branching is
more elaborate, sometimes even extremely ornate, and then re-
sembles that of American forms of JM. alni on Quercus, Cornus,
etc. In the type-specimen the appendages are colorless, or some-
times tinged amber-brown at the base. Burrill says “appendages
usually hyaline, occasionally colored for a distance, the color end-
ing at an abrupt line like a septum." As mentioned below
the occurrence of partially colored appendages is found sporadically
in many forms of M. alni, and no systematic value can be attached
to this character.

M. semitosta Berk. & Curt., on Cephalanthus, has, since its pub-
lication in Grevillea in 1876, been maintained as a distinct species by

138 A MONOGRAPH OF THE ERYSIPHACEAE

American authors. Examination of Berkeley & Curtis' type in the
Kew Herbarium shows the fungus to have these characters : “ per-
ithecia 75-100 » in diameter, appendages 5-9, 3/ to slightly longer
than the diameter of the perithecium, with the tips of the ultimate
branches, when mature, distinctly recurved ; asci and spores as in
M. alni. The appendages are mostly tinged amber-brown in the
lower half, and under low magnification there often seems asharpline
of demarcation between the colored basal part and the colorless up-
per portion. This appearance however, is due merely to the presence
of air in the colored basal part, and is common to several species
of Microsphaera and Uncinula. Sometimes, however, the appen-
dages are faintly colored throughout, and the plant then shows much
resemblance to “ M. erineophila Peck," a form discussed below.
Apart from the more or less colored appendages the form on
Cephalanthus is quite similar to many examples of JZ a/mi on
other hosts, especially to the small form called by Léveillé “ 7.
Hedwigit.”’

Burrill & Earle (61, p. 414) in their key to the genus Micro-
sphaera place M. semitosta is the section “ Tips of the appendages not
recurved,” and M. alni in the section “ tips recurved when mature.”
Burrill, too, says of M. semitosta, “ tips obtuse not recurved.” The
mature apex, however, certainly shows recurved tips, and is, in all
the specimens I have seen, quite similar in all respects to that of
M. alni.

It is worthy of note that Burrill says “ primary branches
long”; so that it appears that the form on Cephalanthus sometimes
shows the same kind of variation from the type as do the Japanese
forms mentioned later.

The only peculiarity, then, that distinguishes M. semitosta
is the more or less colored appendages. This character is, I am
quite convinced, insufficient to separate it from JZ. alni, being one
which, in the forms of this species, cannot be considered of any
systematic value. In specimens of M. alni on Carya sulcata
(Urmeyville, Indiana, Coll. E. M. Fisher, 1890. Ex-Herb. U. S.
Dept. Agric. n. 1148 (specimen now in the Kew Herbarium)) the
appendages are usually colorless, or only fairly tinged, but occa-
sionally here and there one appendage shows a sharply marked off
colored basal part like that which occurs in the Cephalanthus form.

MICROSPHAERA 139

In certain specimens of M. alni on Vicia Americana (usually
named “ M. Ravenelii’’ in herbaria) just the same occasional color-
ing of the appendages is found. In otherwise typical specimens of
M. alni on various hosts I have frequently met with an occasional
colored appendage, e. g., in certain specimens on Platanus occiden-
talis the coloring is limited by a septum-like line exactly as in
* M. semitosta" ; and the same is the case, although rarely, with
examples on Betula alba, where the coloring may extend to three-
quarters the length of the appendage.

M. erineophila Peck * is another with colored appendages which
cannot, it appears, be considered distinct from M. alni ; Peck, in the
original description, says “closely related to M. penicillata [ M.
alni], of which perhaps it may be a mere variety, but it is readily
distinguished by its colored appendages and nucleated spores.’
The “nucleate” appearance of the spores may be safely disre-
garded as a character, and we have then only the colored appendages
as a supposed distinctive cl ter separating the plant from M. alni.
Relying on this point, subsequent American authors have kept up
M. erineophila as a distinct species. I cannot follow this arrange-
ment. In the first place, as mentioned above, we find quite com-
monly in ordinary M. alni the base of the appendages becoming
colored, and in the form described as “ M. semitosta” the color
usually reaches to half the length of the appendage. Ina form of
M. alni on Carya alba (Rab.-Wint.-Pazsch. Fung. Eur. 3953) the
perithecia are exactly similar in size, and in the number and length
of the appendages, to those of “ M. erineophila,” but as regards the
coloring of the appendages are intermediate. The appendages of
some perithecia are quite colorless, of others tinged amber brown
throughout. If we were to separate the form “M. erincophita "
from M. alni, the plant on Carya alba would certainly have to be
included under the former—the appendages consequently would
have to be considered as varying from colorless to colored, and in
the former case the plant would only be characterized by the small
size, short appendages, etc.—characters which, as we have seen in
the case of M. Hedkwigii, are quite insufficient.

With regard to M. erineophila on Fagus ferruginea there
seems some connection between the coloring of the appendages

r
-

* On ** erineum " —galls on the leaves of Fagus ferruginea.

140 A MonoGRAPH OF THE ERYSIPHACEAE

and the occurrence of the fungus on the “ erineum," as we find a
form of M. alni with uncolored appendages, but otherwise cer-
tainly indistinguishable, on the leaves of the same host-plant when
no galls are present.

On the other hand, the coloring-matter appears in the ap-
pendages of JZ alui on other hosts without the occurrence of
galls. This is well seen in the curious form of M. alni on Corylus
rostrata, var. Mandshurica (more fully referred to later on), and
also in a very interesting specimen (now in the Kew Herbarium)
sent to me by Professor Galloway from the Herbarium of the U.
S. Dept. of Agriculture. This specimen was labelled “M. semitosta
B. and C. on Cephalanthus SEN Needham, Indiana. E. M.
Fisher, September, 1890, No. 1154." The material consists of
four leaves; three of these have traces of “erineum ” on them,
while the fourth is quite free. On all the leaves, however, the
perithecia have appendages which are colored throughout, exactly
as in “M. erineophila,’ with which the fungus often agrees in all
characters. On the three leaves where galls are present, the
perithecia, unlike those of “M. erinecophila” on Fagus ferruginea
are scattered over the surface, and occur only rarely, probably
only accidentally, on the galls. Sometimes the appendages are
longer (twice the diameter of the perithecium), and the apical
branching shows signs of becoming more widely forked, when we
are reminded of the form on Corylus rostrata, var. Mandshurica.

In conclusion it is seen from the above remarks that we have
in the series of forms of M. alni ones that show a colored base to
the appendages, others in which the appendages are colored half
way (' M. semitosta "), and finally those in which the color reaches
to the commencement of the apical branching (“M. erineophila,”
and certain forms on Corylus rostrata, var. Mandshurica, and Cepha-
lanthus occidentalis) I feel convinced, therefore, that in M. alni the
absence or presence of color in the appendages must be regarded
as a character of no systematic value.

Nor can we regard M. erincophila as a “ biological species ”
dependent on the gall (as is perhaps the case with Sphaerotheca
phytoptoph la), since we find the same form occurring on leaves of
Cephalanthus occidentalis free from the “ erineum."

M. alni occurs apparently only very rarely on the host, plant

MICROSPHAERA 141

Menispermum Canadense. The form on this host-plant has been
described as a distinct species, M. menispermi E. C. Howe.

Burrill (60), in his critical work on the American species of
Microsphaera, has maintained M. menispermi as a distinct species.
“ Remarkable for the variation in structure and size. In some
perithecia only one ascus is found, while in others in the same
microscopical preparation at least seven have been seen. The
appendages on a single perithecium are somewhat equal in length,
but are often exceedingly variable in the division of the tips.
Sometimes there is only a single fork with two equal, straight,
obtuse branches, and again, the exceedingly ornamental tips fill
the field of the microscope with its complex scroll-work."

Iam indebted to Professor Underwood for sending me an
authentic specimen of M. menispermi from the Ellis Herbarium.
Examination of this specimen (now in the Kew Herbarium) showed
that without doubt the fungus must be referred to M. alni, and,
judging from this specimen ‚alone, it cannot be considered even a
marked form of this variable species. The specimen showed these
characters, mycelium evanescent, perithecia more or less scat-
tered, 100-135 in diameter, appendages 12-20, about equalling
the diameter of the perithecium, colorless, apex 4-6 times closely
and regularly dichotomously branched, tips of ultimate branches
regularly and distinctly recurved, asci 4-8, spores 4-8. The
branching of the apex of the appendages is often very ornate, but
corresponds exactly with that of many common American forms
of M. alni. From some of the characters given by Burrill in his
description—e. g., appendages sometimes seven times the diameter
of the perithecium—it seems just possible that some other plant
may have been under observation. However this may be, it is
safe to consider M. menispermi E. C. Howe as a synonym of M.
alni, as is seen by the characters shown by these authentic speci-
mens (collected by Howe), which agree, moreover, exactly with
Howe's original description.

There is a specimen in the Kew Herbarium labelled “Wicro-
sphaera, on Populus, New York, Gerard, 130.” The fungus on this
is M. alni, and the host-plant P. grandidentata. M. alni has not
been reported on Populus, and in the present case I feel doubtful
whether the perithecia originally grew on the leaves, or have

142 A MONOGRAPH OF THE ERYSIPHACEAE

simply adhered to them. A few perithecia of Phyllactinia corylea
occur also. z

Professor Miyabe has sent me specimens (now in the Kew Her-
barium) of two very interesting forms of M. alni from Japan.
These specimens, while certainly belonging to M. alni, are valu-
able in showing what marked variations occasionally occur. The
first of these forms (on Ligustrum medium) has often quite colorless
appendages and the compact apical branching characteristic of J.
alni; in many perithecia, however, the apex of some of the ap-
pendages forks widely, the primary branches being sometimes quite
long. Not infrequently, also, the appendages are coloredibrown
near the base, and a few perithecia were observed in which the
color, although faint, reached to the base of the apical branching.
The other form, on Corylus rostrata, var. Mandshurica is more re-
markable, and, taken by itself, might certainly be considered dis-
tinct. The appendages of most perithecia are rather long, often
twice the diameter of the perithecium, and are multiseptate and
uniformly colored brown to the commencement of the apical
branching. The apical branching is rather irregular, the primary
branches being frequently long. Nevertheless, even in this form
with usually strongly colored appendages, we get occasionally
colorless appendages, and a small compact apex branched in the
normal manner for M. alni. The wide branching of some of the
appendages of these two forms tends to connect them with the var.
divaricata, while the quite sporadic appearance of colored append-
ages shows that, in M. alni, no value can be attached to this
character.

Magnus (227) in an interesting and well-illustrated paper on
the forms. of M. alni, comments on the curious fact that this
species is abundant on Syringa vulgaris in North America, while
no record exists of its occurrence on this host in Europe.

~ Var. lonicerae (DC.) [Figs. 19-22]

Erystphe lonicerae DC. Fl. Fr. 6: 107. 1815: Tul. Sel. Fung.
Carp. 1: 205. pl. E 4... 1861.

Alphitomorpha divaricata, var. lonicerae Schlecht. Berl. Ges.
Nat. Freund. Verh. 1:49. 18 19.

MICROSPHAERA 143

Erysibe divaricata, var. lonicerae Lk.; Willd. Sp. Pl. 6: 113.
1824.

Erysiphe penicillata, var. lonicerae Fr. Syst. Myc. 3: 244. 1829.

E. divaricata, var. lonicerae Duby, Bot. Gall. 2: vali 1830.

E. divaricata Lk: Johnst. Fl. Berw. 2: 142. 1831.

Alphitomorpha ale, var. caprıfohacearum Walle PA pg
Germ. 2: 754 (partim). 1833.

Erysiphe penicillata Kickx. Fl. Crypt. Env. Louv. 138 (par-
tim). 1835; Berk. in Sm. Engl. Fl. 5: 327 (partim). 1836.

Erysibe penicillata, var. caprifoliaccarum | Rabenh. Deutsch.
Krypt. Fl. 1: 236 (partim). 1844.

Microsphaera Ehrenbergii Lév. Ann. sci. nat. III. I5: 155.
pl. 8. f. 22 (sub Calocladia). 1851; Sacc. Syll. Fung. I: 14,
1882; Wint. in Rabenh. Krypt. Fl. Deutschl. 1°: 39. 1884;
Karst. Act. Soc. Faun. Fl Fenn. 2: 92. 1885; Schroet.;
Cohn's Krypt. Fl. Schles. 3: 244. 1893; Jacz. Bull. l'Herb.
Boiss 4: 748. 1896; Oudem. Rév. Champ. Pays.-Das. 2: 93.
1897.
M. Dubyi Lev. Ann. sci. nat. III. 15: 158. A. ot 26 (sub
Calocladia). 1851; Sacc. Syll. Fung. 1: 10. 1882.

Calocladia Ehrenbergü Lév.; Dietr. Blick. Crypt. Ostseeprov.
336. 1856; Karst. Myc Fenn. 2: 105 . 1873.

Microsphaera lonicerae (DC.) Wint. Rabenh. Krypt. Fl.
Deutschl. 1: 36 (excl. syn. Æ. abnormis Duby). 1884; Karst.
Act. Soc. Faun. Fl: Fenn. 2: 9r. 1885; Schroet. ; Cohn's
Krypt. Fl. Schles. 3: 243. 1893; Jacz. Bull. l'Herb. Boiss. 4:
747. 1896; Oudem. Rév. Champ. Pays.-Bas. 2: 89. 1897.

Exsicc.: Bri. & Cav. Fung. par. 71 ; Desmaz. Pl. Cr. Fr. ed.
I, ser. I, I I 1I, *ed. 2, ser. 1, 511; Kunze, Fung. Select. Exsicc.
319; Sacc. Myc. Ven. 891; de Thüm. Myc. univ. 450, 1056;
Roumeg. Fung. Gall. Exsicc. 767, 827, 1540, 3938; Syd. Myc.
March. 735, *3722, *3919; Rehm. Ascom. 349, 847; Zopf. &
Syd. Myc. March. 83; Westend. Herb. Crypt. Belg. 1388 ; and
112 (a only) (in Herb. Jard. bot. Bruxelles), de Thüm. Fuse:
austr. 135; Oudem. Fung. Weerl Exsicc. 154; Fckl Fung.
Rhen. 696; Rab.-Wint. Fung. Eur. 2651; Rab. Fung. Eur.
*556; and 296 sub M. Hedwigü;, *Erikss. Fung. par. scand.
exsicc. 144, 235; Rab. Herb. Myc. ed. 2, 473-

144 A MONOGRAPH OF THE ERYSIPHACEAE

Amphigenous ; mycelium usually subpersistent and effused
over the surface of the leaf, or forming patches, sometimes evanes-

base, thin-walled above, becoming thick-walled towards the base,
apex 3-4 times more or less closely dichotomously branched,
(rarely trichotomously branched in the branching of the first and
second orders), tips of the ultimate branches mostly straight,
occasionally one here and there recurved ; asci 2-7, usually about
4, broadly ovate to globose, 40-56 x 34-48 p, with or without a
short stalk ; spores 3-6, 20-24 x 10-12 y.

Hosts.—L onicera alpigena, L. Caprifolium, L. flava, L. hispida
(95), L. implexa, L. lutea, L. nigra, L. Periclymenum, L. tata-
rica, L. Xylosteum, Syringa vulgaris (3) (227).

Distribution—Evrore: France, Belgium, Netherlands, Ger-
many, Switzerland, Italy, Austria-Hungary, Sweden, Finland,
Russia.

The present plant differs from M. alni only in the usually more
loosely branched apex, with the tips of the ultimate branches for
the most part straight, with occasionally one here and there re-
curved. At first view, one. is inclined, from analogy, to consider
these few recurved tips as the: mature form, and to dismiss the
straight ones as immature. Examination of considerable material
shows, however, that this view cannot be taken, and that the re-
curved form is really in the present plant the exceptional one.

The extreme form of the var. /omicerae with a loosely and rather
vaguely branched apex, with the ultimate branches more or less
unequal, and their tips all straight, is very different from typical
M. alni with its compact apex and regularly recurved tips. This is
the form described by most authors, who consequently place the
plant in the section of the genus characterized by having the tips
of the ultimate branches not recurved. Léveillé describes this
form (under the name of M. Duéyi), and figures the apex of the
appendages as very unlike that of M. alni. Nevertheless, in the
two specimens of “ M. Dubyi,” on Lonicera Caprifolium and L.
Xylosteum, at Kew, from this author’s herbarium, some perithecia
may be found in which the appendages have the tips of the ulti-
mate branches distinctly (although only here and there) recurved.

MICROSPHAERA 145

Leveillé described the plant on Zonicera tatarica as a distinct
species—M. Ehrenbergü, but it is certainly not distinct from that
on Z. Caprıfolium, etc. Specimens on L. tatarica have, perhaps,
more often recurved tips here and there, and a slightly more com-
pact branching of the whole apex, and shorter appendages than
those on L. Caprifolium, etc., but these characters are certainly
not invariable, and are, besides, frequently met with in, e e, the
plant on Z. Xy/osteum, which has always been referred by authors,
including Léveillé, to Dudyz.

The size of the perithecium and number of the appendages
are very variable; I have seen perithecia, side by side on a leaf,
70 # in diameter with 5 appendages, and 105 rin diameter, with
22 appendages.

The var. Zonzcerae is confined to Europe ; the numerous records
of the plant on species of Lonicera in America all refer to typical
M. alni. This is the case with Cooke and Peck’s record of
“M. Dubyi” in the Journal of Botany (9o, p. 13); with Peck’s
records in the 26th and 29th Reports of the N. York St. Mus.
(278 and 280) on Lonicera glauca, etc., and Saccardo’s record of
"AM. Dubyı” from North America on L. parviflora. In these
American specimens, and in the numerous other ones that I have
seen in herbaria (including one named “M. finitima Howe,” in
the Kew Herbarium), the fungus clearly belongs to M. alni, and
shows no approach whatever to the var. /onicerae of European
honeysuckles. The apex is very ornate with regularly and dis-
tinctly recurved tips, in fact, many of the specimens show exactly
the same elaborate type of branching as that of “ M. pulchra,” a
form of M. a/ui on Cornis alternifolia.

The present plant can scarcely claim a higher rank than that
of a variety of M. alni. Not only do we frequently find some of
the tips of the ultimate branches here and there recurved, but fur-
ther proof of affinity with M. alni is shown by the occurrence, al-
though only very rarely, of an apex in which all the tips are re-
curved, and which taken by itself, would pass for that of M. alni.
This is found, e. g., in the specimens in Oudem. Fung. EEN
Exsicc. no. 154.

As we know that M. alni is an extremely variable plant, all
the above facts lead us to the conclusion that this species has pro-

146 A MONOGRAPH OF THE ERYSIPHACEAE

duced on European honeysuckles a variety, /onicerae, charac-
terized by a slightly different branching of the apex, but which
occasionally shows signs of reverting to the type.

It is, perhaps, of interest to note that in an immature condi-
tion, the apex of the appendages of M. alni, is often exactly sim-
ilar to the mature apex of the var. /omicerae.

Allescher (3) has recorded “ Microsphaera Ehrenbergii” on
Syringa vulgaris from Bavaria, and has stated that the S yringa
affected stood in the immediate neighborhood of a bush of Lonicera
tatarica attacked by the same fungus. Magnus (227, p. 68) has
confirmed the identification, and considers the case to afford con-
clusive proof that the variety Jonicerae (= M. Ehrenbergü) has
here passed over from the Zonicera to the Syringa. The figure
which Magnus gives (loc. cit., f. 16) certainly seems to represent
the apical branching of the var. lonicerae rather than that of M.
alni proper, a species which occurs very commonly on Syringa in
North America.

The present variety /onicerae has hitherto been supposed to be
the only Microsphaera which occurs on Lonicera in Europe ; the
occurrence of M. alni, var. divaricata on Lonicera caerulea in Italy
is noted later.

— Var. divaricata (Wallr). [Figs. 23-26]

Alphitomorpha divaricata Wallr. Berl. Ges. Nat. Freund. Verh.
1:39. 1819; Wallr. Fl. Crypt. Germ. 2: 754. 1833.

Erysibe divaricata, var. Jrangulae Lk.; Willd. Sp..PL 6 : 113-
1824.

E. divaricata (Wallr.) Schlecht. Fl. Berol 2: 169 (partim).
1824; Rabenh. Deutschl. Krypt. Fl. 1:2 36 (excl. syn. Erysiphe
Daphnes Duby). 1844.

Erysiphe penicillata, var. rhamni frangulae Fr. Syst. Myc.
3:244. 1820.

E. divaricata, var. frangulae (Lk.) Duby, Bot. Gall. 2 : 870.
1830.

E. divaricata (Lk.) Secret. Mycogr, Suisse, 2306318477

Microsphaera divaricata Lév. Ann. sci. nat. HE gu. ; 75%.
pl. 8. f. 18 (sub. Calocladia). 1851; Sacc. Syll Fung. I.: 11.
1882; Wint. Rabenh. Krypt. Fl. Deutschl 22: 38. 1884;

MICROSPHAERA 147

Karst. Act. Soc. Faun. Fl. Fenn. 2: 91. 1885; Schroet.; Cohn’s
Krypt. Fl. Schles. 3: 242. 1893; Jacz. Bull. l'Herb. Boiss.
4:749. 1896.

Calocladia !divaricata Lév.; Dietr. Blick. Crypt. Ostseeprov.
335. 1856; Karst. Myc. Fenn. 2: 195. 1873.

Exsicc.: Fckl. Fung. Rhen. 689; Syd. Myc. March. 337;
Karst. Fung. Fenn. Exsicc. 279; de Thüm. Myc. univ. 2151;
Roumeg. Fung. select. exsicc. 4758; *de Thüm. Fung. austr.
140 ; * Westend. & Wall. Herb. Crypt. Belg. 1387 ; *Erikss. Fung.
par. scand. 141; *Erbar. Critt. ser. 1, 142 (sub Zrysiphe loni-
cerae).

Amphigenous; mycelium evanescent or subpersistent and
more or less effused, or forming definite patches; perithecia gre-
garious or scattered, variable in size, 72-136 p in diameter, cells
10-18 4 wide; appendages 4-16, 1 17-5 15, usually 3-4 times the
diameter of the perithecium, flaccid when long, smooth, thin-walled
above, becoming thick-walled at base when nature, colorless and
aseptate, or I-3-septate in the lower half, and then usually dark
brown towards the base, apex 2—4 times dichotomously branched,
primary branches usually long, divergent, and often recurved, tips
of ultimate branches recurved ; asci 3-7, broadly ovate to globose,
usually very shortly stalked, 28—48 x 30-38 0 ; spores 4-6, 18-23
X 9-12 p.

Hosts —Lonicera caerulea, Rhamnus Frangula.

Distribution. — EUROPE : France (307), Belgium, Germany,
Italy, Austria-Hungary, Denmark, Norway, Sweden, Finland,
Russia.

In its extreme form, when the appendages are long, and the
apex is divided into long primary and secondary recurved branches
(Figs. 24-26), the present plant seems distinct enough from M.
alni to claim the position that all recent authors give it as a
distinct species. But in the forms where the appendages are
shorter—sometimes only 1 1% times the diameter of the perithecium,
the branching of the apex not unfrequently becomes closer (Fig.
23), and a relationship with M. alni is then at once apparent.
Nevertheless, it would perhaps be possible to consider M. divaricata
specifically distinct from M. a/ni if we confined ourselves to the
study of European examples of the latter, relying for specific
characters on the longer, flaccid appendages with a loosely-
branched apex in distinction to the short, more or less rigid ap-

148 A MONOGRAPH OF THE ERYSIPHACEAE

pendages with a much more closely and regularly branched apex
of M. alni.

The study of American examples of M. alni, however, at once
shows us that we have long-appendaged forms certainly connected
with this species; it is impossible, e. g., in face of the numerous
intermediates, to regard the plant described as M. exclusa Cooke
and Peck (a form with very long appendages) as anything but a
well-marked variety of M. almi.

More than this, there occurs in America a plant on Vaccinium,
etc., described as M. vaccinii, but which must also be regarded as
a variety of M. alni in which we occasionally find much the same
kind of apical branching as in the var. divaricata. It is even possi-
ble that it will eventually be found necessary to unite the American
variety vaccinii with the European var. divaricata.

Considering these facts, we are forced to the conclusion that
in America, where the species is apparently more abundant than
in Europe, M. alni has varied and produced long-appendaged
varieties on several host plants, while in Europe only one very
similar variety has been produced on Rhamnus Frangula.

A further proof of the relationship of the present plant with M.
alni is afforded by the Japanese specimens of M. alni on Corylus
rostrata, var. mandschurica, which frequently show a loosely-
branched apex with spreading branches.

. Speshnew (338) records M. divaricata on Rhamnus cathartica
from Transcaucasia. As this plant is a common host for M. alnı,
it will be best to wait for confirmation before accepting this record
of the occurrence of divaricata in Asia, on a new host-plant.

Since the above remarks were written I have seen examples—
one in the Herbarium of the British Museum (South Kensington),
and one in the Herbarium of the Florence Museum, of the speci-
men no. 142 (1142) in the Exsiccati “Erb. Critt. Ital. ser. ı.”
(Part of the latter specimen is now deposited in the Kew Her-
barium.) These specimens are labelled ** Erysiphe lonicerae,” and
the host plant is Lonicera caerulea. The fungus, however, is not
the species named (which is described above, as M. alni, var.
lonicerae) but belongs to the present variety divaricata.

These examples on Lonicera coerulea have long flaccid append-
ages, 4-7 times the diameter of the perithecium, with often the

MICROSPHAERA 149

characteristic apical branching of typical divaricata ; sometimes,
however, the branching is slightly more compact.

This occurrence on a species of Lonicera is extremely interest-
ing, as it has been hitherto supposed that the var. divarıcata was
absolutely confined to Rhamnus Frangula, and that the only plant
which occurred on Lonicera in Europe was M. alni, var. lonicerae.

— Var. vaccinii (Schwein.).

Erysiphe vaccinit Schwein. Syn. Fung. Am. Bor. 270. 1834;
Sacc. Syll. Fung. 1: 21. 1882.

Microsphaera vaccinii Schwein. Cooke & Peck Journ. of Bot.
H iers 1872; Peck, Reg. Rep. 33: 05. 19735 Sacc: Syll
Fung. 1: 13. 1882; Burr & Earle in Bull. Ill. State Lab. Nat.
Hist. 2: 417. 1887; Atkins. Journ. Elisha Mitch. Sci. Soc. 7 : 70.
1891 ; Burr. in Ell. & Everh. N. Amer. Pyren. 25. 1892.

AM. elevata Burr. ; Bull. Ill. State Lab. Nat. Hist. 1: 58.
pl. 2. f. 4. 5. 1876; Sace. Syll. Fung. 1: 770. 1882; Burr &
Earle, Bull. Ill. State Lab. Nat. Hist. 2: 427. 1887; Sacc. Syll.
Fung. 9: 369. 1891; Burr. ; Ell & Everh. N. Amer. Pyren.

Exsicc.: Ell North Amer. Fung. 430; Rab.-Wint. Fung.
Eur. 3539; *Seym. &. Earle, Econ. Fung. 145; SEIL & Everh.
Fung. Columb, 506.

Epiphyllous, rarely amphigenous ; mycelium persistent, very
thin and effused over the upper surface of the leaf, or forming ir-
regular patches, sometimes completely evanescent; perithecia
globose or globose-depressed, more or less scattered, very variable
in size, 70-145 5 in diameter, cells 10-20 » wide; appendages
4-22, 214-8 times the diameter of the perithecium, rather delicate
and thin (about 5 4 wide), sometimes slightly angularly bent,
flexuose, flaccid, colorless or occasionally amber-brown at the base,
smooth or sometimes slightly rough towards the base or for most
of the length, aseptate thin-walled above, becoming thick-walled
below when mature, apex 2-4 times dichotomously branched,
branching variable, sometimes very close and compact, sometimes
widely forked, with the primary branches long and occasionally
recurved, tips of ultimate branches regularly and distinctly re-
curved ; asci 2-16, 45-72 x 28-38 p, ovate or ovate-oblong, with
or without a short stalk ; spores 4-6, 18-22 x 10-13 f.

Hosts.—Andromeda sp., Catalpa bignonioides, C. speciosa,
Epigaea repens, Gaylussacia resinosa, Lyonia paniculata (371),

150 A MONOGRAPH OF THE ERYSIPHACEAE

Vaccinium Canadense, V. Myrtillus, vars. macrophyllum and micro-
Phyllum (151), V. Pennsylvanicum, V. vacillans.

Distribution. —NORTH AMERICA: United States—New Hamp-
shire, Massachusetts, Connecticut, New York, New Jersey, Mary-
land, West Virginia, (249) North Carolina, Ohio, Michigan, In-
diana, Alabama, Illinois, Wisconsin, Missouri, Iowa, Wyoming.
Canada— Ontario.

The present plant is extremely variable in nearly all its char-
acters.

Schweinitz, in 1834, first described the plant as growing on
Vaccinium Pennsylvanicum, as Erysiphe vaccinii; in 1872 Cooke
& Peck described a plant on Vaccinium vacillans as Microsphaera
vaccinii, giving E. vaccinii Schwein. (partly) as a synonym.

Burrill has maintained M. vaccinii (Schwein.) Cooke & Peck
as a species, and has described the appendages as “6-20, hyaline,
smooth, slightly colored at base, 2 or 3 to as many as 6 times the
diameter of the perithecium, branching various, usually 3 or 4

_ times forked, with the tips truncate or bifid, not recurved, occa-

sionally more ornate, with tip distinctly recurved. This is a vari-
able species not only in the character of the mycelium, but in the
length and branching of the appendages. In most cases the tips
are swollen and not at all recurved.”

I am indebted to Professor Earle, Professor Ellis, Professor
Underwood, and other American botanists for numerous speci-
mens of the American forms of Microsphaera on Vaccinium and
Fpigaca.

In the first place, it is evident, from the study of these, that it
is incorrect to consider, as has been hitherto done in America, all
the forms that grow on species of Vaccinium as belonging to
“M. vaccinii” On E. corymbosum the only fungus that I have
seen is certainly to be referred to M. alni type; this is, no doubt,
the plant recorded by Cooke & Peck (90, p. 12) as “ M. Friesü
Lev. var. vaccinii.”

On other species of Vaccinium, however, and on Epigaea, the
fungus differs from M. alni in having long, very flaccid, thinner
appendages, with the apical branching much more variable. Bur-
rill’s description of the tips of the ultimate branches as “truncate
or bifid, not recurved " undoubtedly refers to the immature condi-
tion only.

MICROSPHAERA 151

On the whole, the present plant appears clearly marked off
from typical M. alni by the long flaccid appendages, and their
usually more irregularly branched apex. It is more difficult to
separate it from M. alni var. extensa. I do not think it advisable
at present, however, to unite these two forms. In the var. vac-
cini the apex of the appendages is almost constantly more irregu-
larly and widely branched than that of the var. extensa, indeed the
primary branches are sometimes long, divergent, and slightly re-
flexed as in the var. divaricata. In the var. extensa the apex is
usually as ornate and as closely branched as in certain forms of
typical M. alni. It must, however, be mentioned that cases have
occurred, although very rarely, where the apical branching of the
var. vaccinii has been quite similar to that of the var. extensa, and
it is certainly possible that these two varieties will eventually have
to be united.

I feel no hesitation in considering M. elevata Burrill, on Catalpa,
as a form of the present plant.

At first sight this form, which occurs on Catalpa bignonioides
and C. speciosa appears to have these distinctive characters:
smaller perithecia with fewer appendages, and a smaller more
closely branched apex. The size the perithecium, however, is
certainly variable, not only in this form on Catalpa, where it ranges
from 70-130 p in diameter, but also in the plant on Vaccinium and
Epigaea. In Cooke & Peck's type of M. vaccinii at Kew, the
perithecia, although varying between wide limits, average 115%;
in other specimens, e. g., those in Ell. N. Amer. Fung. no. 430,
the perithecia are smaller, about 95 » in diameter. In specimens
on Epigaea repens, in which the apical branching of the appen-
dages is the same as that of the plant on Vaccinium, the perithecia
are frequently only 85 o in diameter. As regards the number of
the appendages, this is about 14 in Cooke & Peck’s type, in
Ellis’ specimen fewer (7 or 8), and on Zpigaca frequently only 4
or 5. Nor is the small compact closely-branched apex of the ap-
pendages absolutely characteristic of the plant on Catalpa, as I
have seen just the same characters in a specimen on Vaccinium
(now in Kew Herbarium) sent to me by. Professor Underwood.
The same, small, compact apex is also seen in the plant on Gay-
lussacia resinosa, which has been referred by all authors to M.

vaccini,

152 A MONOGRAPH OF THE ERYSIPHACEAE

— Var. extensa (Cooke & Peck). -[Fig. 18]

M. extensa Cooke & Peck, Journ. of Bot. II. 1: 12. 1872;
Peck, Reg. Rep. 25: 1873; Sacc. Syll. Fung. 1: 13. 1882.

M. quercina (Schwein.) Burr. ; Burr. & Earle, Bull. Ill. State
Lab. Nat. Hist. 2: 424 (avidin: 1887; Burr.; Ell. & Everh.
N. Amer. Pyren. 28 (partim). 1892.

M. quercina (Schwein.) Burr., var. extensa Atkins. Jour. Elisha,
Mitch: Sci. 506,7: 72. 1891.

Exsıcc.: Rab.-Wint. Fung. Eur. 5033; de Thuem., Myc.
univ. 756; Kellerm. & Swingle, Kans. Fung. 11.

Epiphyllous ; mycelium persistent, effused or forming irregu-
lar spots ; perithecia more or less densely gregarious, often forming
floccose patches 90-140 y in diameter, averaging 115 yp; cells
10-20 # wide ; appendages 8-19, 214-6 times the diameter, of the
perithecium, rather delicate, flexuose, flaccid, narrow (about 5 A
wide), sometimes slightly angularly bent, usually smooth, occasion-
ally rough at the base, colorless, aseptate, thin-walled throughout,
or rarely becoming thick- walled towards the base, apex 3-5 times
more or less closely dichotomously branched, tips of ultimate
branches regularly and distinctly recurved ; asci 3—8, ovate or
broadly ovate, shortly stalked, 58-72 x 34-45 p; spores 4-8,
usually 6, large, 22-26 X 12-15 #

Hosts.—(Quercus alba, Q. discolor, Q. nigra, Q. palustris, Q.
rubra.

Distribution —NoRTH |. AMERICA: United States—Massachu-
setts, New York, Pennsylvania, New Jersey, North Carolina (9), In-
diana, Illinois, Wisconsin, Missouri, Kansas.

The variety erzensa differs from the type in the longer, narrower,
flaccid appendages and slightly larger spores. The branching of
the apex is not as a rule different from that of certain forms of
M. aint, and is much closer and more elaborate than that of the
var. vaccinü. Cases occur, however, although rarely, in which
the manner of branching of the apex is the same in these two
plants ; the var. vaccinii can then be separated by its larger spores.

The present plant was described as a species, M. extensa, by
Cooke & Peck, but there can be no doubt that it is too close to
M. alni to be allowed this position. In its well-marked state the
appendages are about 4% times the diameter of the perithecium,
flaccid, and narrow, and so appear very different from the stouter

MICROSPHAERA 153

(7 4 wide), more or less rigid appendages of M. alni. Certain
specimens, however, especially some on Quercus alba, show all in-
termediate stages between M. alni, and the var. extensa, and in
these it is clearly seen that as the appendages become shorter they
become, pari passu, stouter, and gradually pass into those of ordi-
nary M. alni as it occurs on oaks. The specimens in Ellis’ N.
Amer. Fungi, no. 429, show such intermediate stages between M.
alni and the var. extensa.

Hosts.— Quercus aquatica, Q. laurifolia, Q. nigra.

Distribution.—NoRTH AMERICA : United States—South Caro-
lina, Alabama, Florida.

The peculiar variation of growth shown in the axial elongation
of the apex of the appendages constitutes a striking character at
first sight (see Figs. 15-17), and one which might, if constant, be
considered of specific value.

The character, however, is certainly not invariable. On the
perithecia of specimens belonging to the var. calocladophora, we
quite commonly find single appendages which show the same regu-
larly dichotomous apical branching as that found in the forms of
M. alni on American oaks.

On the other hand, in certain specimens of otherwise typical
M. alni, we find a single appendage here and there showing the
axial elongation characteristic of the var. calocladophora. As an
instance of this may be mentioned the specimens in the Herbarium
at the British Museum (South Kensington) labelled “ M. extensa,
on fallen leaves of water oak. Quercus aquatica, Aiken, South
Carolina. H. W. Ravenel, Nov., 1881," and “ M. pulchra" on
Cornus alternifolia. In both these specimens, among perithecia
with appendages normal for M. alni, there occurs rarely a single
appendage with the apex formed as in the var. calocladophora.

In the face of these connecting links on both sides, it is impossi-
ble to consider the present plant as specifically distinct. Under-
wood and Earle (371, p. 178) have some interesting remarks on
this point. |

— Var. calocladophora (Atkins.) [Figs. 15-17]

M. densissima EIL S Mart. Journ. Myc. I : 101. 1885; Sacc.
Syll. Fung. Addit. ad. Vols. L-IV.: 2. 1886and 9: 368. 189r.

154 A MONOGRAPH OF THE ERYSIPHACEAE

M. calocladophora Atkins. Journ. Elisha Mitch. Sci. Soc. 7: 73
(cum icon.) 1891; Burr. in Ell. & Everh. N. Amer. Pyren. 29.
1892; Sacc. Syll. Fung. 1: 253. 1895.

Exsıcc.: *Seym. & Earle, Econ. Fung. 179; Rab.-Wint.
Fung. Eur. 3538; Ell. & Everh. N. Amer. Fung., sec. ser. 1538;
Rav. Fung. Amer. Exsicc. 625, sub M. extensa.

Main axis of many of the appendages not dividing dichotomously
at the apex, but growing on and bearing sets of opposite branches,
which occasionally show the same axial elongation ; asci 62-75
X 42-45 t; spores large, 24-28 x 12-15 p.

— Var. ludens var. nov. [Figs. 27-30]

Perithecia more or less densely gregarious ; appendages nu-
merous, often crowded, about 175 times the diameter of the peri- `
thecium, usually flexuose-contorted or angularly bent, apex usually
very irregularly and widely branched, 4-5 times dichotomous, pri-
mary branches usually rather long, and those of the subsequent
orders unequal and irregularly placed, with the tips straight ; some-
times the branching is closer and more regular, with the tips dis-
tinctly recurved ` asci and spores as in M. alni

Hosts.— Vicia Americana and vars. linearis and truncata.

Distribution —NoRTH AMERICA: United States—South Da-
kota (Brookings (D. Griffiths, Aug. 1892) and Snoma (Griffiths
and Carter, Aug. 1897)), Wyoming (French Creek, Williams and
Griffiths, Aug. 1898).

Among the duplicate specimens (now in the Kew Herbarium)
sent to me from the fine collection of Erysiphaceae made by Grif-
fiths in Dakota, Wyoming and Montana there are examples of a
Microsphaera, growing on the species of Vicia named above, which
are very difficult to place.

Griffiths has named and recorded this Microsphaera as M. dif-
fusa. This led me to examine again all the material of M. diffusa
at my disposal, and to compare them with the present plant.

From all specimens seen of M. diffusa Griffiths plant differs
in possessing, frequently, a recurved tip to the ultimate branches.
Sometimes we find a single appendage with the tips all regularly
and distinctly recurved, and the mode of branching of the whole
apex not very unlike that of M. alni, and certainly like that of
some of its varieties, e. g., var. divaricata (Figs. 28, 30). On the
other hand a large proportion of the appendages show an apical

MICROSPHAERA 155

branching of a very different type to that of JZ alni ; the branch-
ing being very lax and irregular, with straight tips to the ultimate
branches (Figs. 27, 29).

In the latter case there is much resemblance to M. diffusa,
but in that species we find the ultimate divisions (of the mature
apex) forming long, rather slender, nearly parallel branches.
These long ultimate branches are characteristic of M. diffusa,-and
are not found in the present plant, in which, moreover, as men-
tioned above, we frequently find some appendages with recurved
tips, another character which never occurs in M. diffusa.

The appendages of the present plant are usually angularly
bent, or even more or less contorted ; this character together with
that of the great variability in the apical branching, give much the
appearance of a “sport” ; but as the plant has been collected in
three different localities on different host plants, it can hardly be
dismissed as this.

M. euphorbiae has the same curiously contorted appendages,
but differs in the longer appendages, with very flexuous apical
branching, etc. If we consider the bent appendages as a character
of the first importance, the present plant should rank as a variety
of M. euphorbiae rather than of M. alni; but it is possible that
the more or less contorted growth of the appendages is due, in
the present case, merely to the great crowding of the perithecia
and the consequent interlacing of their appendages. Moreover,
in some perithecia the appendages are nearly or quite straight;
this is, however, very exceptional.

. Except in the very variable nature of the apical branching, and
the contorted appendages, the present plant does not differ from
M. alni.

The usually very lax and irregular apical branching certainly
separates the present plant widely from the ordinary forms of M.
alni, and it is only the occasional occurrence of appendages with
‘recurved tips and a closer type of branching that has led to its
being placed, with some hesitation, as a new variety under M.
alni. ;

It may be well here to review the position of these six vari-
eties of M. alni. In America we have the four varieties extensa,
calocladophora, vaccinii, and ludens. The position of these to the
type may be stated as follows :

156 A MONOGRAPH OF. THE ÉRYSIPHACEAE

Var. exfeusa is a robust form produced on certain species of
oaks, and in its extreme state is very distinct in the long flaccid
appendages. The apical branching does not deviate from the or-
nate type commonly found in American examples of M. alni on
oaks. The spores appear to be distinctly larger. A complete
series of intermediate forms exist connecting this variety with the
type.
Var. calocladophora is another robust form, similarly confined
to certain American oaks. The distinguishing character is the
axial elongation shown in the apex of most appendages. The
spores are large. Connecting links, both on the side of the vari-
ety and of the type, are occasionally found. `

Var. vaccinii differs from the two varieties mentioned above
in the smaller spores, and in the variable nature of the apical
branching of the appendages. The long, thin appendages and
usually looser apex distinguish it from the type, although as the
appendages tend to become shorter, they become stouter, with the
apical branching more approaching that of M. alni. Certainly
allied to the European var. divaricata.

Var. /udeus occurs on Vicia Americana, and is known at once
by the more or less contorted appendages, with very lax and vari-
able apical branching. The tips of the ultimate branches are very
frequently straight.

e two European varieties are /ozicerae and divaricata.

Var. /onicerae.—This has perhaps some claim to be consid-
ered a distinct species which has been evolved on species of Loni-
cera in Europe, perhaps in the same way as M. berberidis has on
Berberis ; to this species, indeed, the present variety shows some
affinity. On the other hand, relationship with M. alni is shown
in the fact that the characteristically straight tips of the var. /on:-
cerae are occasionally recurved as in this species.

Var. divaricata.—This has hitherto been supposed to be con-
fined to Rhamnus Frangula ; asingle occurrence, however, on Zon-
icera nigra has been noted. Inits extreme form this variety is very
different from any European forms of M. alni in the long, divergent,
usually reflexed branches of the apex of the long appendages.
Oceasionally, however, the appendages are shorter, and the apical
branching more like that of M. alni. Intermediate forms also

MICROSPHAERA 157

exist. This variety shows great affinity with certain forms of the
American var. vaccinit.

5. M. GROSSULARIAE (Wallr.) Lév. [Figs. 34, 37 and 43]

Alphitomorpha penicillata, var. grossulariae Wallr.; Berl. Ges.
Nat. Freund. Verh. 1: 40. 1819; Wallr. Fl. Crypt. Germ. 2: 755.
1833.
A. grossulariae Wallr. Ann. Wett. Ges. 4 : 236.

Erysibe penicillata, var. grossulariae Lk.; Willd. Sp. Pl. 6:
114. 1824; Rabenh. Deutschl. Krypt. Fl. 1: 236. 1844.

Erysiphe penicillata, var. grossulariae Fr.; Syst. Myc. 3 : 244.
1829 ; Duby, Bot. Gall. 2: 871. 1830.

E. penicillata Spreng.; Fl. Hal. 581 (partim). 1832; Berk.
Sm. Engl. Fl. 5 : 327 (partim). 1836.

Microsphaera grossulariae Lév. Ann. sci. nat. III. 15 : 160.
pl. 9. f. 25 (sub Calocladia). 1851; Cooke, Micr. Fung. 220.
1865 ; Cooke, Handb. Brit. Fung. 2 : 649. 1871; Wint. Rabenh.
Krypt. Fl. Deutschl 17: 37. 1884; Karst. Act. Soc. Faun. Fl.

1892; Schroet. Cohn's Krypt. Fl. Schles. 3: 244. 1893 ; Jacz.
Bull. l'Herb. Boiss. 4 : 747. 1896; Oudem. Rev. Champ. Pays.-
Bas. 2:90. 1897.

Calocladia grossulariae (Lév.) Dietr. Blick. Crypt. Ostseeprov.
S27. 1856.

Erysiphe grossulariae (Lév.) de Bary, Beitr. Morph. Phys.
Pilz I: Sxi $2. 1500

Microsphaera Van-Bruntiana Ger. Bull: Torr. Club, 6: 31.5
1875; Sacc. Syll. Fung. 1: 14. 1882; Atkins. Journ. Elisha
Mitch. Sci. Soc. 7: 71. 1891.

Podosphaera grossulariae (Lév.) Quel. Champ. Jur. Vosg. 3:
106. 1875. |

Exsicc.: Rab. Fung. Eur. 1044; Fckl. Fung. Rhen. 697 ;
Roumeg. Fung. Gall. Exsicc. 1539, 2167; Syd. Myc. March.
734; de Thüm. Fung. austr. 136, 460; Ell. N. Amer. Fung. 769,
1324; Cooke, Fung. Brit. Exsicc. ed. sec. 284; Desmaz. Pl. Cr.
Fr. ed. I, ser. 1, I IIO, "ed. sec., Ser. I, 510; Vize. Fung. Brit.
94; Flor. Gall. et Germ. Exsicc. 598; Rab.-Wint. Fung. Eur..
3247; Rehm. Ascom. 849; *de Thüm. Myc. univ. 2242; *Ell.

158 A MONOGRAPH OF THE ERYSIPHACEAE

& Everh. Fung. Columb. 315; *Erikss. Fung. par. scand. 142;
*Krieg. Fung. saxon. 725.

Epiphyllous or amphigenous ; mycelium evanescent, or sub-
persistent, thin and effused on the upper surface of the leaf; peri-
thecia scattered to densely gregarious, globose-depressed, very
variable in size, 65-130 y in diameter, cells 14-20 nm wide ; ap-
pendages 5-22, I-134 times the diameter of the perithecium,
colorless, smooth, aseptate, thin-walled above, becoming thick-
walled in the lower half, when mature, apex 4- 5 times closely and
regularly dichotomously branched, branches of the first and second
orders very short, all the segments deeply divided (giving a some-
what digitate appearance to the whole apex), ultimate branches
forming a narrow fork, tips not recurved; asci 4-10, broadly
= ovate or oblong, usually with a very short stalk, 46-62 x 28-
38 4; spores 4-6, very rarely only 3, variable in size, 20-28 x
12-16 p.

Hosts —Ribes floridum (6), R. Grossularia, R. nigrum (6), R.
rotundifolium (6), R. sanguineum, Sambucus Canadensis, S. race-
mosa and var. pubescens.

Distribution —EvroPE: Britain, France, Belgium, Netherlands
(263), Germany, Switzerland, Austria-Hungary, Denmark, Sweden,
Finland (196), Russia.

Asia: Japan.

NORTH AMERICA: United States—Vermont, Massachusetts,
New York, Pennsylvania, West Virginia (249), North Carolina
(13), Ohio, Indiana, Alabama (12), Illinois, Wisconsin, Missouri,
Kansas (386), Montana (6), California (159).

A well-marked species in the deeply divided segments of the
appendages. The branches of the first and second orders are very
short, so that the divisions of the segments reach nearly to the
center, giving a somewhat digitate and very characteristic appear-
ance to the whole apex (see Figs. 34, 35).

The American M. Van-Bruntiana (on Sambucus Canadensis) is
identical with the present species, although in the original descrip-
tion the branches of the appendages are described as “truncate at
their apices." When mature, however (Fig. 43), the branches
are bifid in just the same manner as in M. grossulariae, and the
original description was no doubt taken from an immature appen-
dage, such as is shown at Fig. 36, drawn from an American

specimen.

MICROSPHAERA 159

M. grossulariae is confined in Europe to Rides Grossularia ; in
America it attacks several other species of Aes, and also, very
frequently, Sambucus Canadensis and S. racemosa.

Professor Miyabe has sent me specimens on Sambucus racemosa
var. pubescens from Japan. This is the first record of the occur-
rence of the species in Asia.

In Europe M. grossulariae sometimes occurs in such quantities
on cultivated gooseberries as to cause a disease. In the Journa}
of the Board of Agriculture for 1898 (184) it is reported that this
disease was very troublesome in England during that year, caus-
ing the leaves of the gooseberry-bushes affected to shrivel and fall
off. The following notes on prevention and remedies are given :
“ The leaves from infected bushes should be raked from under them
and burnt. . . Any dead leaves remaining on infected trees should
be picked off and burned, as far as possible. Where there is a
sign of infection the leaves should be dusted thoroughly above
and below with very finely powdered sulphur put carefully on with
a knapsack powder-distributer on a still, hot, sunny day. Sul-
phide of potassium diluted with water in the proportion of 2% oz.
of sulphide to five gallons of water, and sprayed over and under
the leaves in a fine spray, has been found to be efficacious. This
dressing should be applied very early when the leaves are small
and young, and should be repeated in about sixteen days."
Bordeaux mixture, composed of 3 lbs. of sulphate of copper and
3 lbs. of lime to 25 gallons of water, or if used later in the season
when the foliage is strong and fully developed, composed of 4 Ibs.
of sulphate of copper and 4 lbs. of lime to the same quantity of
water, is also recommended.

The American “ gooseberry mildew,” which attacks chiefly the
berries, is Sphaerotheca mors-uvae.

6. M. Mouceorı Lév. [Figs. 59, 60]

M. Mougeotii Lév. Ann. sci. nat. III. I5: 158. pl. 9. f. 24 (sub
Calocladia). 1851; Cooke, Mier. Fung. 219. 1865; Cooke
Handb. Brit. Fung. 2: 649. 1871.

Erysiphe Mougeotii de Bary, Beitr. Morph. Phys. Pilz. 1-
SH oi 1870.

. Podosphaera Mougeotii (Lév.) Qual. Champ. Jur. Vosg. 3:
106. 1875.

160 A MONOGRAPH OF THE ERYSIPHACEAE

Microsphaera Lycü (Lasch.) Sacc. E Roum. Michelia, 2:
310. . 1881; Sacc. Syll. Fung. 1: 10. 1882; Wint.; Rabenh.
Krypt. Fl. Deutschl. 17: 37. 1884; Schroet.; Cohn’s Krypt.
Fl Schles. 3: 243. 1893; Jacz Bull. l'Herb. Boiss. 4: 745.
1896; Oudem. Rev. Champ. Pays.-Bas. 2: 89. 1897.

Exsicc.: de Thuem. Fung. Austr. 461 ; Roumeg. Fung. Gall.
exsicc. 1165, 2740; Rab. Fung. Eur. 1428 ; Syd. Myc. March.
837; de Thuem. Myc. Univ. 2152.

Amphigenous ; mycelium thin, effused and subpersistent, or
evanescent; perithecia usually epiphyllous, sub-gregarious or
scattered, globose-depressed, 115-170 yz in diameter, cells obscure,
8-13 4 wide; appendages very numerous and densely crowded,
about equalling the diameter of the perithecium, flaccid, thin-
walled throughout, aseptate, smooth, colorless, sometimes slightly
nodulose, apex 2-3 times dichotomously branched, or occasion-
ally, especially in the branching of the first order, trichotomously
divided, branching very loose, irregular, and widely spreading,
tips of ultimate branches not recurved ; asci 10-18, ovate or ovate-
cylindrical, often somewhat truncate at apex, shortly stalked,
48-56 X 24-30; spores 2, 20-24 x 12-15 u

Hosts —Lycium barbarum, L. Europaeum, L. ovatum (56) (319).
L. ruthenicum (307) (394).

Distribution.—Evrore : Britain, France, Belgium (44) (209),
Netherlands (263), Germany, Italy (307), Austria-Hungary,
Russia, (172).

A very distinct plant, differing from all other species of the
genus in the densely crowded, widely branched appendages and
the 2-spored asci.

The appendages at first spread upwards, so that the perithecium,
seen from above, appears enveloped in a white mycelium-like mass ;
eventually the appendages become reflexed, and the exposed upper
half of the perithecium becomes concave. The appendages
usually branch at about half their length, and fork widely, measur-
ing from 100-150 it across the apex.

M. Mougeotii is confined to Europe ; the species recorded under
this name from North America proves to be M. diffusa.

Saccardo and Roumeguere, followed by all modern authors,
uses the name M. Lyci (Lasch.) for the present species. This name,
however, published in Sacc. Fung. Gall. ser. III. no. 1174 (1850),

MICROSPHAERA 161

was not accompanied by a diagnosis, and therefore cannot take
precedence over Léveillé's name Mougeotii (1851).

7. M. piFFUsA Cooke & Peck. |Figs. 31-33]

AL diffusa Cooke & Peck, Journ. of Bot. II. 1: 13. 1872;
Peck, Reg. Rep. 25: 95. 1873; Sacc. Syll. Fung. 1: 12. 1882;
Burr. & Earle, Bull. Ill. State Lab. Nat. Hist. 2: 416. 1887;
Atkins. Journ. Elisha Mitch. Sci. Soc. 7: 69. 1891; Burr.; Ell. &
Everh. N. Amer. Pyren. 24. 1892.

M. symphoricarpi E. C. Howe, Bull. Torr. Club, 5: 3. 1874;
Burr. & Earle, Bull. Ill. State Lab. Nat. Hist. 2: 417. 1887;
Sacc. Syll. Fung. 9: 369. 1891; Burr.; Ell. & Everh. N. Amer.
Pyren. 24. 1892.

Exsicc. (sub M. diffusa): Ell. & Everh. N. Amer. Fung.
sec, ser. 1540; Rab.-Wint. Fung. Eur. 3654; Rav. Fung. Amer.
Exsicc. 628. (Sub M. symphoricarpi); Rab.-Wint. Fung. Eur.
3655; Ell. N. Amer. Fung. 768; Rehm. Ascom. 846; "SEIL &
Everh. Fung. Columb. 224.

Amphigenous ` mycelium persistent, thin and effused, or sub-
persistent and forming vague patches, or quite evanescent ; peri-
thecia scattered or gregarious, globose-depressed, very v ariable in
size, 55-126 p in diameter, averaging 90-100 p, cells We? D
wide ; appendages very variable in number and length, 4-30, or
rarely crowded and as many as 50, 1%-7 times the diameter of
the perithecium, smooth, aseptate or 1—3-septate in the lower half,
colorless or pale brown towards the base, flaccid when long, thin-
walled above, becoming thick-walled towards base, apex 3-5 times
dichotomously or sub-dichotomously divided, branching diffuse
and irregular, branches of the higher orders sub-nodulose, often
apparently lateral, tips of ultimate branches not recurved ; asci
4-9, 48-60 x 28-30 p, ovate-oblong with a very short stalk ;
spores 3-6, usually 4, 18-22 x 9-11 y.

Hosts. —Sub JM. diffusa) Apios tuberosa, Desmodium Cana-
dgnse, D. canescens (265) (324) 366), D. cuspidatum (61), D. pan-
iculatum, D. sessilifolium, Glycyrrhiza lepidota, Lespedeza ge
L. hirta, L. striata, L. violacea, Phaseolus pere nnis. (Sub M.
symphoricarpi) Symphoricarpos occidentalis, S. orbiculatus, S. race-
mosus and var. pauciflorus (6).

Distribution.—NORTH AMERICA: United States (sub M. diffusa)
—Connecticut, New York, Pennsylvania, South Carolina, Ohio

162 A MONOGRAPH OF THE ERYSIPHACEAE

(324), Michigan, Alabama, Illinois, Mississippi, Wisconsin, Mis-
souri, Iowa, Minnesota, South Dakota, Kansas, Montana, Wyo-
ming. (Sub M. symphoricarpi) Pennsylvania, Virginia, Ohio,
Indiana, Illinois, Missouri, North and South Dakota, Kansas,
Montana, Idaho, Colorado, California, Washington.

A species very variable in every character except the irregular
diffuse branching of the apex of the appendages, in which a good
specific distinction is found. The dichotomous nature of the branch-
ing ceases in the higher orders, so that the youngest branches are
irregularly arranged, and often appear as lateral outgrowths; a
slightly nodulose appearance of the branches is also characteristic
of the present species (see Figs. 31, 32).

After seeing a large amount of material, I feel convinced that
the plant on Symphoricarpos—M. symphoricarpi, E. C. Howe,
should be referred to M. diffusa. In this form the perithecia are
perhaps slightly smaller on the average, although the size varies
greatly (I have seen contiguous perithecia on a leaf measuring 55
and 104 p in diameter); the appendages are usually fewer
(4-24), and tend to become longer than in typical M. diffusa; but
these characters are not constant. In certain specimens on Am:
phoricarpos, perithecia taken from the same leaf show a variation
in the length of the appendages of from 1 % to 7 times the diameter
of the perithecium ; while, on the other hand, M. diffusa on other
host-plants frequently possess appendages reaching to four times
the diameter of the perithecium,* and as few as 12 in number. In
the peculiar character of the apical branching of the appendages
the form on Symphoricarpos agrees well with M. diffusa, and as
this is, I consider, the most important specific character, I feel lit-
tle hesitation in treating the two plants as one species. It is nec-
essay to point out that in the form on Symphoricarpos the appen-
dages are very slow in reaching their full development, and unless
perfectly mature examples are examined, the apex of the appen-
dages appears less diffusely branched. In specimens with a fully
developed apex, however, as is the case, e. g., with those on S.
occidentalis (Fort Collins, Colorado (C. F. Baker) and on 5.
racemosus (Datah Co., Idaho, June, 1897 (L. F. Henderson)) both

* Burrill & Earle fae P- ssi Lise Proin specimens on Lespedeza capitata with
appendages ‘“‘ 5 or 6 ti

MICROSPHAERA 163

in Professor Earle’s Herbarium—the identity in the nature of the
apical branching of the form on Symphoricarpos and of M. diffusa
on other hosts is clearly seen.

Burrill (60) remarks on “ M. symphoricarpi (which is given
specific rank)" ; “much like some forms of M. vaccinii.” The lat-
ter plant is, however, far removed in the distinctly recurved tips of
the ultimate branches of the apex of the appendages.

M. diffusa has been recorded on Lathyrus ochroleucus by
Burrill (60) and Trelease (366). From the remarks of the latter
author, however, that the appendages were “absolutely indistin-
guishable from those of M. pulchra “ there can be no doubt that
the fungus was really M. alni. Vicia is also given as a host-plant
by Burrill (60) for the present species, but it seems probable that
M. alni, var. ludens has been mistaken for M. diffusa in this case.
I have seen specimens of typical M. a/ni on both Lathyrus ochro-
leucus and Vicia Americana. i

The records of M. Mougeotii Lév. (M. Lycii) from America
belong to the present species.

8. M. RussELLII Clinton. [Figs. 38, 39]

M. Russellii Clinton ; Peck, Reg. Rep. 26: 80. 1874; Sacc.
Syll Fung. ı: 12. 1882; Burr. & Earle, Bull. Ill. State Lab.
Nat. Hist. 2: 415. 1887; Burr; Ell. & Everh. N. Amer. Pyren.
25 - T1805

Exsicc.: Ell. & Everh. N. Amer. Fung. sec. ser. 2008, 3517 ;
*Seym. & Earle, Econ. Fung. 270, 270b ;* Ell. & Everh. Fung.

small, 6-14 x wide ; appendages 5-14, 3-7 times the diameter of

very irregular and lax, primary branches usually long and forking
widely, tips of ultimate branches not recurved ; asci 4-9, narrowly
to broadly ovate, or (in small perithecia) ovate-globose, shortly
stalked, 42-56 x 24-32 #; spores 3-5, usually 4, 18-22 x I0-

2 p.
Hosts.—Oxalis corniculata, var. stricta, O. Suksdorfii, O. violacea
(60).

164 A MONOGRAPH OF THE ERYSIPHACEAE

Distribution —Nortu AMERICA : United States—Vermont, New
Hampshire, Massachusetts, New York, West Virginia (249), Ohio,
Indiana, Illinois, Wisconsin, Missouri, Iowa, Washington. Canada
—Ontario.

Very distinct among the species of the genus in the long flac-
cid colored appendages. The nature of the final branching of the
apex of the appendages is very hard to see in M. Russellu, as in
this species, as in many of the genus Microsphera, the appendages
are extremely slow in arriving at maturity, and perithecia are fre-
quently found in which the asci and spores are formed, although
the appendages are still unbranched. Figs. 38, 39 represent the
most branched form of the apex of the appendages that I have
seen. Burrill (60) says “ appendages simple, bifid, or two or three
times irregularly branched, branches long, often distorted, tips not
swollen or recurved.”

g. M. EUPHORBIAE (Peck) Berk. & Curt.

Erysiphe euphorbiae Peck, Reg. Rep. 26: 80. 1874; Sacc.
Syll Fung. 1: 18. 1882.

Microsphaera euphorbiae Berk. & Curt. Grevillea, 4: 160.
1876 ; Sacc. Syll. Fung. 1: 13. 1882 ; Burr. & Earle, Bull. Ill.
State Lab. Nat. Hist. 2: 418. 1887; Atkins Journ. Elisha
Mitch, Sci. Soc. 7: 70. M. 1. f. 1-4. 1891 ; Burr.; Ell. & Everh.
N. Amer. Pyren. 26. 1892.

M. coluteae Kom. Scripta Bot. Hort. Univ. Imp. Petropol. 4:
270. 1895.

Exsicc.: Ell. N. Amer. Fung. 431; Rab.-Wint. Fung. Eur.
3246 ; Jacz.-Kom.-Tranz. Fung. Ross. Exsicc. 79

Amphigenous; mycelium usually subpersistent, thin and ef-
fused, sometimes evanescent; perithecia often gregarious in floc-
cose patches, but sometimes scattered, 85-145 x» in diameter,
rarely reaching to 180 u, globose-depressed, cells 10-15 » wide; .
appendages 7-28, 217-8 times the diameter of the perithecium,
usually narrow (about 5 4 wide), more or less flexuose-contorted
angularly bent, and nodulose, but sometimes wider and not an-
gularly bent, always very flexuose, colorless, thin-walled above,

very irregular and lax, branches strongly flexuose, often more or
less curled, lips of ultimate branches straight or recurved ; asci

MICROSPHAERA 165

4-13, more rarely 13-26, ovate or ovate-oblong, with a short
stalk, 48-66 x 26-35 m; spores usually 4, sometimes 3, 5 or 6,
19-21 x 10-12 p.

Hosts — Astragalus adsurgens, A. Cooperi, A. Drummondiü, A.
Mortoni, Colutea arborescens, C. cruenta, Euphorbia corollata, E.
hypericifolia, E. marginata (60) (386), E. Presti.

Distribution.—AsiA : Turkestan.

NORTH AMERICA : United States—New York, North and South
Carolina, Michigan, Alabama (12), Illinois, Mississippi, Wisconsin,
Missouri (363), Iowa, Kansas, Montana, Colorado.

A very interesting and marked species in the contorted angu-
larly-bent appendages, which occur almost constantly in all ex-
amples, and when present, are sufficient, taken in conjunction with
the flexuose branching of the apex, to identify the species at
once. Where the appendages are not thus characterized, e. g., as
in the form on Colutea (referred to below), the best distinctive
character is found in the very vaguely and widely branched apex
of the appendages, the branches of which are irregularly ar-
ranged, very flexuose, or variously contorted and twisted.

Up to the present time, M. euphorbiae has been considered as
occurring only on species of Euphorbia, but I have no hesitation
in referring to this species American plants occurring on Astragalus
adsurgens, A. Cooperi, A. Drummondii, and A. Mortont. The
fungus on A. Cooperi has been recorded by Peck (60) (91) (280)
as “ M. holosericea Lev.” [M. astragali ] ; that on A. adsurgens I
have found labelled ** M. Ravenelii” in herbaria, and that on A.
Mortoni named Erysiphe communis. All the specimens on the
species of Astragalus mentioned above have the same peculiarly
contorted appendages and irregular branching of the apex as occur
in examples of M. euphorbiae on species of Euphorbia.

Komarov (206) has recently described a species of Micro-
Sphaera, occurring on Astragalus and Colutea in Turkestan, under
the name of M. coluteae, with the following diagnosis: “ Bifrons,
mycelio arachnoideo, persistente, bene evoluto. Conceptaculis
minutis subglobosis. Appendiculae graciles, conceptaculo multo
longiores, uncinatae, ramulis ultimis apice turgidis incurvis. Asci
8 subovoidei brevi pedunculati. Sporae in quovis asco 2-6,
saepius 3-4. Conidiis cylindrico-ovoideis. Conceptacula ad 9o s

166 A MONOGRAPH OF THE ERYSIPHACEAE

appendices 300—400 4; asci 42-45 X 22-504; sporae 14-22 X
5-14 4; conidia 28-32 x 10-13 fe.

I have seen the following examples, of this plant: Jacz.-Kom.-
Tranz. Fung. Ross. Exsicc. nr. 79, “in fol. vivis Astragali SP
Ad. fluv. Seravschan (Turkestan)" ; a specimen in the Herbarium
of the University of St. Petersburg, from “ Darch, 6000 feet.
Seravschan" super, “ on Colutea cruenta Ait." ;anda specimen from
the same locality as the last, on Colutea arborescens, in Professor
Tranzschel's herbarium. These two forms on Colutea and Astra-
galus are sightly different. On the former host-plant the fungus
forms conspicuous floccose patches, due chiefly to the appendages
being more assurgent than usual; the perithecia are large, 100-
180 4 in diameter, the appendages are 7-28 in number, and very
long, reaching sometimes to 8 times the diameter of the perithe-
cium, not angularly bent, nor nodulose, though very flexuose, usu-
ally slightly rough for nearly the whole length ; the apical branch-
ing is very wide—often measuring more than 200 jr wide—and
irregular, and the branches are very flexuose and contorted ; the
asci are 6-23 in number, with 4—5 spores. On Astragalus the ap-
pendages are intricately contorted and angularly bent, but the
branching of the apex is often identical with that of the form on
Colutea, although the branches are frequently even more flexuose
and curled, the ultimate ones being sometimes almost spirally
coiled. Good figures of these two forms have been given by Mag-
nus (231. f. 8-73).

The characters shown in the branching of the apex, and, in the
form on Astragalus, in the peculiar contorted appearance of the
appendages, certainly in my opinion, refer “ M. coluteae” to M.
euphorbiae. l had already, before seeing Komarov's specimens,
referred American forms on certain species of Astragalus to M.
euphorbiae, and I now feel convinced that we have this species oc-
curring in North America on Euphorbia and Astragalus, and in
Asia on Astragalus and Colutea.

I have not seen any examples of M. euphorbiae from Europe.
Bommer and Rousseau (45) have recorded “ Erysiphe euphorbiae
Peck,” in a conidial stage on Euphorbia amygdaloides from Bel-
gium ; it is quite possible, however, that this fungus may prove to
be Sphacrotheca tomentosa (S. mors-uvae). European specimens in

MICROSPHAERA 167

herbaria, named Æ. euphorbiae Peck ” have all proved on exami-
nation to be this species of Sphaerotheca. Lambotte (209 supp.),
however, records a plant from Belgium, which may possibly be-
long to M. euphorbiae. It is recorded as “ Erysiphe euphorbiae
Peck,” but the brief description given is not sufficient to identify
the plant with certainty ; Theques largement ovées 3—4, spores 3—4,
épaisses, 25 x 16 ; appendices peu longs, flexueux, colorés ; périthe-
ces petits ; mycelium mince. Feuilles d'Euphorbe."

I follow Burrill in regarding Microsphaera euphorbiae Berk. &
Curt. as identical with Erysiphe euphorbiae Peck ; I have not seen
an authentic specimen of the latter. Burrill speaking of M. eu-
phorbiae, says (60, p. 26) “Erysiphe euphorbiae is evidently the
same thing. The name seems to have been founded upon speci-
mens in which the appendages were not branched.”

ro. M. Guarinonu Bri. & Cav. [Figs. 42, 44]

M. Guarinonii Bri. & Cav. Fung. Par. n. 172 (cum diag. et
icon.) 1892; and in Hedwigia, 31: 142. 1892; Cav. in Atl.
Istit. Bot. Pavia, II. 3: 329. 1894; Sacc. Syll. Fung. I1: 252.
1895.

Exsicc.: Bri. & Cav. Fung. Par. 172.

Amphigenous; mycelium subpersistent, effused ; perithecia

primary branches long, widely spreading, and more or less re-
curved, sometimes more compact, tips of ultimate branches re-
curved when mature; asci 4-10, ovate-oblong, with or without a
short stalk, 55-68 x 30-38 /4; spores usually 6, sometimes 4 or 5,
20-23 x 10-13 A.

Host.—Laburnum vulgare.

Distribution —EUROPE : Italy.

A very beautiful species, quite distinct in the very long, flex-
uose appendages, 3-4 times dichotomously branched, with the
tips of the ultimate branches recurved.

Briosi and Cavara show the ultimate branches recurved, but
figure the tips of these as straight ; this, however, is not the form
of the mature apex (see Figs. 42, 44). The asci are described as

168 A MONOGRAPH OF THE ERYSIPHACEAE

8-spored, but in the specimens I have examined no ascus has con-
tained more than 6 spores.

M. Guarinonii has hitherto been recorded from only a aM
locality in Italy—Varallo, where it was discovered in 1891, and
published the next year in Briosi and Cavara's Exsiccati. I have,
however, seen specimens from two other Italian localities. One
is contained in the Herbarium of the Florence Museum. This
specimen was named Zrysiphe Martii, “ on the leaves of Cytisus
Laburnum, Boscolongo, 1877 (Da Borzi)," with the note attached
* appendicibus longissimis hyalinis, ascis ovatis in pedicello pro-
ductis, 8-sporis.” The other specimen was recorded by Mas-
salongo (237, p. 127) as “ M. astragalt B cytisi,' from S. Mauro
di Saline, Verona, October 5, 1892.

11. M. umsırıcı Kom. [Figs. 45, 46]

M. umbilici Kom. Scripta Bot. Hort. Univ. Petropol. 4: 270
1895.

Exsicc.: Jacz. -Kom. -Tranz. Fung. Ross. Exsicc. 29.

Amphigenous ; mycelium evanescent ; perithecia scattered or

ing rather close, branches of the higher orders more or less irreg-
ularly placed, tips of the ultimate branches not recurved ; asci
4-14, ovate-oblong, shortly stalked, 58-70 x 23-38 u ; spores 3-
5, 22-25 X 10-13 D

“ Mycelio Seen persistente, matricis superficiem totam
occupante. Peritheciis minutis subglobosis. Appendiculae peri-
theciis aequantes rectae breves ad basin leniter coloratae, ramulis
ultimis apice turgidis. Ascis in quovis perithecio 5-8, ovoideis
vel ellipsoideis brevipedunculatis ; sports 3-2 cylindrico ovoideis.
Conidiis cylindricis utrinque rotundatis. Peritheciis 90-120 p ; ap-
pendiculis 90-130 ; ascis 40-54 x 30-45 ; sporis 16-22 x 8-12;
conidiis 25-32 x 8-12” (Kom. Zee. cit.).

Host —Cotyledon Semenovii (= Umbilicus Semenovii).

Distribution. —Asıa ` Turkestan (Seravschan).

I have not seen sufficiently mature examples of this plant to be
able to express an opinion as to its position. The only specimens
examined (from which my description was drawn up) have been those

MICROSPHAERA 169

in the exsiccati quoted. These specimens, although many peri-
thecia contain asci and spores, are too immature to show with cer-
tainty the form of the mature apex of the appendages. The most
developed stage in the branching of the apex that I have seen is
shown at Fig. 45. It is, however, possible that this does not
represent the final form, and the somewhat swollen tips of many
of the branches rather favors the view that further division takes
place. It is frequently the case in species of Microsphacra that
the asci and spores are developed long before the apical branching
of the appendages has attained its mature form.

12. M. FERRUGINEA Erikss. [Figs. 56-58]

M. ferruginea Erikss. Fung par. scand. n. 145 (cum diag.)
1883; Erikss. Bidr. Kanned. vara odl. växt. sjuk. 46. 1885.

Exsıcc. *Erikss. Fung. par. scand. 145.

Amphigenous ; mycelium subpersistent ; perithecia scattered,
70-100 4 in diameter, cells small, rather regular, 10-12 f wide;
appendages 4-7, rarely 7-10, about 1% times the diameter of the
perithecium, colorless, smoth, thin-walled above, becoming thick- `
walled below, apex 3-4 times dichotomously branched, branching
rather vague and lax, tips of the ultimate branches not tecutved ;
asci 4—6, ovate- oblong, with or without a short stalk, 45-52x 26
—30 #; spores 4-?, 20XI

“ Caespites amphigeni, E pulveracei, demum late ef-
fusi et confluentes. Conidia utrinque rotundata, pallide fusca, pel-
lucida, 28-32 yp longa, 16-18. y lata. Perithecia fusco-atra,
sparsa, mycelio densissimo arachnoideo persistente intexta, 80-90
pin diam. Appendices 6-10, perithecium aequantes vel duplo
longiores, 4-6: eis dichotomae, hyalinae. Asci 6-8 in quoque
perithecio, 44-50 y longi, 26-30 y lati. Sporae 6-8 in quoque
asco, 16-18 u longae, 10-12 1 latae. (Erikss. Zoc. cit.)

Host —Verbena hybrida (cult.).

Distribution. —EUVROPE : Sweden.

The specimen which Professor Eriksson kindly sent to me for
examination from his herbarium, and that in the Exsiccati quoted,
are unfortunately both immature. Only a very few perithecia are
sufficiently mature to show any apical branching at all of the ap-
pendages. Figs. 56 and 57 show the apex of the most developed
appendages seen, but it is very possible that the form here rep-
resented is not that of the fully mature apex. It would be hardly

170 A MONOGRAPH OF THE ERYSIPHACEAE

wise, therefore, to express any opinion as to the position of the
species.

Eriksson (119) gives the following account of the damage
caused by M. ferruginea to cultivated plants of Verbena hybrida.
“So sind seil mehreren Jahren zu Rosendal alle Freilandgruppen
von Verbena hybrida stark mehlthaukrank gewesen. Dieser Mehl-
thau sucht aufangs hauptsächlich die Unterseite der Blätter heim,
die ein bleichrostfarbiges Aussehen mit hier und da eingestreuten
Staubgruppen von derselben Farbe bekommen, bis endlich das
Blatt ganz eingesponnen ist. Die Pflanze hat jetzt eben so wie an-
dere mehlthaukranke Pflanzen ein mehr oder weinger weisses
Aussehen ausgenommen. . . . Da die Krankheit trotz reich-
lichem Schwefeln fortdauert, so hat man sich schliesslich genö-
thigt gefunden, mit der Cultur der Verbenen, wenigstens der
älteren, durch Stecklinge vermehrten Varietäten fast gänzlich
aufzuhóren . . . Bei Rosendal hat man in den letzten Jahren
aus Samen, die un Frühjahre ausgesäet waren, kräftigere und dem
Mehlthaue weinger ausgesetzte Exemplare gezogen."

13. M. BÄunrerı P. Magn. [Figs. 52-55]

P. Bäumleri P. Magn. Bericht. Deutsch. Botan. Gesell. 17:
148. Pl. 9. f. 17-18. 1899.

M. Marchica P. Magn. Bericht. Deutsch. Botan. Gesell. r7:
149. Pl. 9. f. 19. 1899.

Exsicc.: Rehm. Ascom. 249 sub Erysiphe Martii.

Hypophyllous (very rarely amphigenous); mycelium subper-
sistent or evanescent ; perithecia more or less densely gregarious
in floccose patches covering the surface of the leaf, globose-de-
pressed, becoming hemispherical, 80-150 in diameter; appen-
dages 8-20, usually 8-14, 4-6 times the diameter of the perithe-
cium, flaccid, penicillate when mature, smooth or slightly rough,
colorless, thick-walled at base, apex about 3 times dichotomously
branched when mature, branching vague and lax, branches of the
higher orders more or less irregularly placed, tips of the ultimate
branches not recurved ; asci 4-12, ovate to oblong, usually shortly
stalked, 55-70 x 30-38 5; spores 4-6 (8 recorded by Magnus),
20-22 x 10-12 p. ;

Hosts.— Vicia cassubica, V. sylvatica,

Distribution —EvRoPE : Britain (Scotland), Italy, Austria-
Hungary, Germany, Russia.

MICROSPHAERA 111

When working through the material of the Erysiphaceae in the
Kew Herbarium at the end of last year, I noticed certain speci-
mens named “ Erysiphe communis” in Berkeley's herbarium (on
Vicia sylvatica, from Scotland), and others named “ Æ. Marti,” in
Rehm’s Ascomyc., n. 249 (on V. cassubica, from Franken), which
clearly belonged to the genus Microsphaera. This was also the
case with specimens sent as “ Æ. Marti,” about the same time, by
Professor Massalongo from Italy, and with Russian specimens,
named “Æ astragali?’ in Professor Tranzschel's Russian her-
barium—both on V. sylvatica.

These specimens showed the apex of the appendages about
three times dichotomously branched, with the branching vague
and irregular. A very slow development of the apical branching
was evidently characteristic of the plant, and the appendages in
this and other characters closely resembled those of M. astragali,
to which species I had intended referring the plant as a new
variety, differing from the type in the more branched apex of the
appendages.

Magnus (231) has since described the plant on Vicia sylvatica,
(from Hungary), as a new species, Microsphaera Bäumleri, and has
at the same time published another species, M. Marchica, on V-
cassubica.

M. Bäumleri is described as follows: “ Sie hat schóne lange
Appendiculae, die an den Enden ein bis vier Mal dichotom
getheilt sind. Die letzten Verzweigungen der Appendiculae sind
stets ziemlich lang und stets gerade vorgestreckt, vorne stumpf
abgerundet ohne jede Spur einer Krümmung. . . Sie ist durch die
ziemlich langen, wenig divergirenden, gerade vorgestreckten, vorn
stumpf abgerundeten Enden der letzten Gabelungen der Appen-
diculae vor den anderen in der alten Welt auf Papilionaceen auf-
tretenden Microsphaeren recht ausgezeichnet. Auch bei ihr kom-
men zuweilen unverzweigte Appendiculae vor. Der Durchmesser
- der Perithecien is durchschnittlich 120 a. Der Ascus enthàlt
meist 8 Sporen. Die Ascosporen sind 18 » lang und 10 a
breit. Sie schliesst sich der M. diffusa C. et P. am

M. marchica is thus described : “Die Perithecien sind 110—
130 p breit «s. Die Appendiculae entspringen von der oberen
Hälfte des kugeligen Apotheciums und richten sich meist

172 A MONOGRAPH OF THE ERYSIPHACEAE

schopfartig auf, wie bei M. astragali. Sie sind meist einfach, nur
selten an der Spitze zweitheilig oder zweimal zweitheilig. Sie sind
etwa vier—bis sechsmal so lang als das Perithecium. . . . Die
Appendiculae sind an den Enden breit abgerundet stupt s
Auch schliesst sie sich verwandtschaftlich der M. coluteae Kom.
und M. Bäumleri P. Magn. nahe an.”

Professor Magnus has very kindly sent me specimens (now in
the Kew Herbarium) of M. Mäumleri and M. Barchica. M. Baum-
leri shows the characters as given in my description above.

M. Marchica I consider is founded on an immature stage of the
same species. In Magnus’ figure (231, f. 79) the appendages are
represented as unbranched, and in the diagnosis are said to be
“ meist einfach, nur selten an der Spitze zweitheilig oder zweimal
zweitheilig." The specimens sent by Professor Magnus (which
agree with the description given) are certainly too immature to show
the nature of the final branching of the apex. The appendages in
these specimens are either undivided at the apex, or have begun to
fork once or twice. The specimens on the same host (Vera cas-
subica) in Rehm’s Ascomyc. n. 249, which certainly represents
the same plant, is much more mature, and the appendages here
show so close a resemblance in their branching to that of M.
Bäumleri, and the habit of the two plants are so similar, that I feel
bound to consider them as belonging to one species.

The other plant on Vicia sylvatica mentioned by Professor Mag-
nus (231, p. 148), of which specimens were sent, I consider also
to be M. Bäumleri in an immature condition.

The affinity of M. Bäumleri is certainly with M. astragali. M.
diffusa, to which the present species has been compared, differs
widely in the shorter, non-penicillate appendages, more branched
apex of the appendages, etc. In M. astragali the appendages are
usually unbranched, sometimes once forked, or rarely twice dicho-
tomous. I have once, however, seen a specimen in which the
apex showed signs of becoming 3 times dichotomously branched.
(Fig. 47). How far the usually unbranched condition of the ap-
pendages of M. astragali is to be considered as the result merely
of immaturity, remains at present doubtful; it is possible that
further investigations of fully mature specimens may prove that
_ the apex becomes branched regularly in age, and even that M.

_ Béumleri should be united with M. astragali.

ERYSIPHE 173

M. cuonymi, also, is related to the present species in the peni-
cillate (though usually shorter) appendages, but differs in the
closer and more elaborate branching of the appendages.

M. Bäumleri has hitherto been recorded only from Germany
and Austria, but specimens from the following countries belong
here: Scotland, New Pitsligo (specimen in Herb. Berkeley at
Kew) ; Italy, Verona (Massalongo, Sept., 1887); Russia, Bologov,
prov. Novgorod (Tranzschel, Aug., 1897).

ERYSIPHE Hedw. f.; DC. (emend. Lév.) Ann. sci. nat. III.
I5: 161. 1851
Perithecia globose, or globose-depressed, sometimes becoming
concave; asci several, 2-8-spored. Appendages floccose, simple
or irregularly branched (never with a definite apical branching),
sometimes obsolete, usually more or less similar to the mycelium
and interwoven with it, very rarely (Æ. tortilis) brown, assurgent
and fasciculate. Etym. engt, robigo.
Distribution. —Europe, Africa, Asia, Australia, New Zealand,
North America—8 species and ı variety.

The genus is characterized by the floccose appendages (some-
times obsolete or apparently absent), simple or vaguely branched,
more or less similar to the hyphae of the mycelium, and frequently
interwoven with them. Sphaerotheca is distinguished by the single
ascus. Æ. tortilis has a habit approaching that of some species of
Microsphaera—a genus connected on its side with Erysiphe through
M. astragalı.

Key to the Species of Erysiphe

1. Asci (of mature perithecia) not ‘containing spores on the living host-plant. 2
Asci (of mature perithecia) containing spores.
2. Perithecia large, 135-280 u in diameter, av eraging 200 u, more or less immersed
n the lanuginose persistent mycelium . graminis.
ege smaller, 80-140 4, not edi in a lanuginose Rn 3.
3. Haustoria lobed. Se
Haustoria not lobed. 2, Stage
4. Asci 2-spored, rarely (and never uniformly) 3- spored. S:
Asci 3-8-spored, rarely (and never uniformly) 2- -spored. 8.
LT dam 52-60 u in diam.; asci 3, 48-50 X 2 28-36 u. 8. trina.
240 u in diam.; asci more than 3, larger. 6.
6. Zëmmer large, becoming pezizoid, 135-240 in diameter, usually about 200 u;

asci 7-38, usually about 20, 75-110 u long, averaging 90 u, spores së Ge
long, averaging 32 X 18 u long. 6.

174 A MONOGRAPH OF THE ERYSIPHACEAE

Perithecia 80-140 u (very rarely 100—175); asci 4-25 (very rarely as many as 36).
usually 10-15, 58—90 = long ; spores 20-28 u long, averaging 34 X 14 u.
7. Haustoria lobed.

3. galeoßsidis.
Haustoria not lobed.

2. cichoracearum,
8. Perithecia =. gn u in diameter, usually about 90 u; asci usually few, 2-8, rarely
2, 46-72 (rarely 80) u lo
äeren Ge 130-280 u in diameter, averaging. 180-200 u ; asci 9-42, ro-
115 a lon

9. Appendages very long, 10-20 times the diameter of the perithecium, assurgent and
fasciculat 5. žortilis.
Appendages ER or short, spreading horizontally, often interwoven pes the my-

I. golygoni.

IO. Perithecia more or less immersed in the lanuginose persistent mycelium.

4. graminis.
Perithecia not immersed in a badge persistent mycelium.

II. Spores 4-6, 20-22 X 10-1 E age var. sepulta.
Spores 8, rarely 6 or 7, RR roundish, 16-20 X 10-15 u 7. aggregata.

I. ERYSIPHE PoLyconı DC. [Figs. 132-139, 143, 155, 158]

Mucor Erysiphe Linn. Syst. Veg. 825 (partim). 1774.

Sclerotium Erysiphe Pers. Obs. Myc. 1 : 13 (partim). 1796;
Pers. Syn. Meth. Fung. 124 (partim). 1801.

S. Erysiphe, var. herbarum Alb. & Schwein. Consp. Fung.
Lusat. 76. 1805.

Erysiphe polygoni DC. Fl. Fr. 2 : 273. 1805.

E. convolvuli DC. Fl. Fr. 2 : 274. 1805.

E. pisi DC. Fl. Fr. 2: 274. 1805 ; Grev. Scot. Crypt, FE 3 :
J^ 734. 1825.

E. heraclei DC. Syn. Pl. Fl. Gall. 57. 1806.

E. aquilegiae DC. Fl. Fr. 6: 105. 1815.

E. scandicis DC. Fl. Fr. 6: 107. 1815.
E. varium Fr. Obs. Myc. 1 : 206 (partim). 1815; and 2 : 366.
1818.

Erysibe pycnopus Mart. Fl. Crypt. Erlang. 329. 1817.

E. macropus Mart. Fl. Crypt. Erlang. 329. 1817.

Alphitomorpha communis Wallr. Berl. Ges. Nat. Freund. Verh.
I : 31 (excl. vars. graminearum, labiatarum, cichoracearum). 1819;
Wallr. Fl. Crypt. Germ. 2 : 758 (partim). 1833.

A. urticae Wallr. Ann. Wett. Ges. 4: 238. 1819.

A. trifoliorum Wallr. Ann. Wett. Ges. 4: 238.

A. hyperici Wallr. Ann. Wett. Ges. 4: 239. 1819

ERYSIPHE 175

A. heraclei Wallr. Ann. Wett. Ges. 4: 240. 1819.
A. pisi Wallr. Ann. Wett. Ges. 4: 241. 1819.
Erysibe polygoni DC.; Gray, Nat. Arr. Brit. Plzrz:g99- r921;
. Schroet. Cohn’s Krypt. Fl. Schles. 3: 234. 1893.

E. pisi DC.; Gray, Nat. Arr. Brit. Pl. x: 589. 1821; Schroet.
Cohn’s Krypt. Fl. Schles. 3: 236. 1893.

E. convolvuli DC.; Gray, Nat. Arr. Brit. Pl. 1: 589. 1821.

Erysibe communis Fic. & Schub. Fl. Gegend. Dresd. 2: 304.
1823; Lk. Willd. Sp. Pl. 6: 105 (excl. vars. graminum, labiata-
rum, cichoraccaruin). 1824 ; Rabenh. Deutschl. Crypt. Fl. 1: 232
(partim). 1844.

Erysiphe trifolii Grev. Fl. Edin. 459. 1824.

E. lathyri Grev. Fl. Edin. 460. 1824.

E. robiniae Grev. Fl. Edin. 460. 1824.

E. asperifoliorum Grev. Fl. Edin. 461 (partim). 1824.

E. ranunculi Grev. Fl. Edin. 461. 24.

[?] Exysibe epimischa (Physalis) Lk. ; Willd. Sp. Pl. 6: 110.
1824.
Erysiphe communis Grev. Scot. Crypt. Fl. Synops. 9. 1828;
Fr. Syst. Myc. 3: 239 (partim). 1829; Duby, Bot. Gall. 2:
869 (excl. vars. graminum, labiatarum, cichoracearum. 1830;
Berk.; Sm. Engl. Fl. 5, pt. 2, 325 (partim). 1836; Dur. &
Mont. Fl. d’Algér. (Crypt.) 565 (excl. var graminis). 1846-9;
Liv. Ann, sek nat EE 171.. DE fr Je 38%. 1851} Tal. Sel
Fung. Carp. 1: 214. 1861; Cooke, Micr. Fung, 221. $l. 72.
f. 240-242. 1865 ; de Bary, Beitr. Morph. Phys. Pilz. 1 : $xiii. 50.
1870; Cooke, Handb. Brit. Fung. 2: 652. 1871; Karst. Myc.
Fenn. 194. 1873; Sacc. Syll Fung. 1: 18. 1882; Wun:
Rabenh. Krypt. Fl. Deutschl. 17: 32. 1884; Karst. Act. Soc.
Faun. Fl. Fenn. 2: 93. 1885; Burr. & Earle, Bull. Ill. State
Lab. Nat. Hist. 2: 402. 1887; Atkins. Journ. Elisha Mitch.
Sci. Soc. 7:64. 1891; Burr.; Ell. & Everh. N. Amer. Pyren.
10. 1892; Jacz. Bull. l'Herb. Boiss. 4: 731. 1896; Oudem.
Rev. Champ. Pays.-Bas. 2: 97. 1897.

Perisporium erysiphoides Fr. Syst. Myc.3: 251. 1829.

Erysiphe daphnes Duby, Bot. Gall. 2: 370; . 1830.

Alphitomorpha nitida Wallr. Fl. Crypt. Germ. 2: 757. 1833.

Erysiphe liriodendri Schwein. Syn. Fung. Am. Bor. 269.

176 A MONOGRAPH OF THE ERYSIPHACEAE

1834; Sacc. Syll. Fung. 1: 21. 1882; Burr. & Earle, Bull. Ill.
State Lab. Nat. Hist. 2: 401. 1887; Burr.; Ell. & Everh. N.
Amer. Pyren. 10. 1892.

Erysiphe macularis Kickx. Fl. Crypt. Env. Louv. 138 (par-
tim). 1835.

E. Perisporium Cord. Icon. Fung. 2: 28. pl. 15. f. 99. 1838.

Erysibe nitida (delphinit) Rabenh. Deutschl. Krypt. Fl. 1:
234. 1844;

Erysiphe convolvuli sepii Cast. Cat. Pl. Mars. 188. 1845.

E. ranunculi Cast. Cat. Pl. Mars. 189. 1845.

E. polygoni Cast. Cat. Pl. Mars. 189. 1845.

Erysibe ulmariae Desmaz. Ann. sci. nat. III. 6: 66. 1846 ;
Desmaz. Fl. Crypt. Fr. ser. 1, n. 1515. 1846; *Desmaz. Mém.
Soc. Roy. Sci. Lille for 1846: 141. 1847; Desmaz. Ann. sci.
nat. II. 8: 14. 1847.

Erysiphe Martti Lév. Ann. sci. nat. III. I5: 166. pl. ro.
f. 34 (syn. excl. partim). 1851; Cooke, Mier. Fung. 220. pl. zr.

f. 237-239. 1865; Cooke, Handb. Brit. Fung, 3: Osr.: 187%;
Karst. Myc. Fenn. 2: 193. 1873; Sacc. Syll Fung. I: 1g.
1882; Wint; Rabenh. Krypt. Fl. Deutschl. 1?: 31. 1884; Karst.
Act. Soc. Faun. Fl. Fenn. 2: 93. 1885 ; Jacz. Bull. l'Herb. Boiss.
4: 728. 1896. Oudem. Rev. Champ. Pay.-Bas. 2: 97. -1397:

E. densa Berk. Hook. Fl. Nov. Zeal. 2: 208. ‘pl. ros. f. 16.
1855; Hook. Handb. New Zeal. Fl. 637. 1867; Sace. Syll
Tang i: 18. IBB?

E. ulmariae Desmaz.; Kickx. Fl. Crypt. Fland. 1 : 381. 1867;
Sacc. Syll Fung. 1: 19. 1882; Oudem. Rév. Champ. Pays.-
Basi2: 99. 1897.

E. umbelliferarum de Bary, Beitr. Morph. Phys, Pilz. 1: § xiii.
50. 1870; Sacc. Syll. Fung. 1: 17. 1882; Wint.; Rabenh. Krypt.
Fl. Deutschl. 1?: 31. 1884; Karst. Act. Soc. Faun. Fl. Fenn. 2:
93. 1885; Oudem. Rév. Champ. Pays.-Bas. 2: 96. 1897.

E. vernalis Karst. Myc. Fenn. 2 : 193. 1873; Karst. Helsing.
Faun. Fl. Fenn. Notis. 13: 247. 1874; Sacc. Syll. Fung. I:
19. 1882; Karst. Act. Soc. Faun. Fl. Fenn. 2: 93. 1885.

E. Marti Lév. f. acaciae Erikss. Bid. Kanned. vara odlade vaxt.
sjuk. 51. 1885.

Erysibe heraclei DC. ; Schroet. ; Cohn’s Krypt. Fl. Schles. 3:
239. 1893.

ERYSIPHE geyi

Erysiphe communis, var. umbelliferarum (de Bary) Jacz. Bull.
l Herb. Boiss. 4: 733. 1896; Jacz.-Kom.-Tranz. Fung. Ross.
Exsicc. no. 130 (cum diag.). 1896.

E. communis, var. ulmariae Jacz. Bull. l Herb. Boiss. 4: 734.
1896.

Microsphaera caraganae Magn. Bericht. Deutsch. Bot. Ge-
sellsch. 17: 150. AM. 9. f. 1-4. 1899.

Erysiphopsis parnassiae Halsted, Bull. Torr. Club, 26: 594.
1899.

Exsicc.: Bri.e Cav. Fung. par. 173; Rab. Fung. Eur. 31,
562, 563, 564, 1057, 1060, 1061, 1062, 1063, 1064, 1065, 1068,
1069, 1426, 1431, 1522, 1736, 1918, 2027, 2134, 2415, 2521;
Syd. Myc. March. 198, 338, 653, 659, 838, 839, 980, 981, 1077,
1142, 1143, 1198, 1240, 1638, 2222, 2328, 2658, 2659, 2765,
*3669, *3671, *3718, *3822, *3914, *3915, *3916, *3917,
* 4241, and 432, 655, 1541, 1640, 3052 sub .SpAaerotheca Casta-
gnei; Fckl. Fung. Rhen. 660, 661, 662, 663, 664, 665, 666,
667, 668, 669, 671, 675, 676, 677, 678, 679, 680, 681,
682, 683, 684, 685, 686, 687, 1738, 1742, 1743, 1744, 2914
and 432, 1541, 3052, sub Sphaerotheca Castagnei; Rab. Herb.
Myc. ed. 2, 462, 466, 467, *476, 477, 479, * 480, 482, 483, *486,
670; Roumeg. Fung. Gall. Exsicc. 1376, 1379, 1534, 1539, 1983,
2072, 2074, 2373, 2450, 2556, 2557, 3226, 3646, 3741, 4565,
and 3645, sub E /amprocarpa ; Desmaz. PL Crypt. Pr. ser G
166, 264, 265, 459, 1108, 1304 (B only), 1515, 1518, 2197, 2198;
ser. 2; 671, 672; "ed. 2, 8er. 1, 109, 508 (A only), 813, 1015,
1018, 1847, 1848; Jacz.-Kom.-Tranz. Fung. Ross. Exsicc. 130;
de Thuem. Fung. exot. dec. 12, sub Æ. /amprocarpa ; de Thuem.
Fung. austr. 143, 144, 145, 146, 239, 240, 241, 447, 448, 449,
453, 454, 455, 458, 651, 652, 857, 955, * 1044, I 141, 1143, 1240,
1241, 1242, 1243 and 457 sub Z. horridula ; and 1237 sub Mi-
crosphaera astragali ; Sacc. Myc. Ven. 68, 149, 150, 151, 602,
603, 604, 605, 609, 610, 695, 786, 787, 896, 897, 898, 1170;
Rehm. Ascom. 350, 398, 399, 449, 500, 546, 547, 650, 799,
800; Fries, Scleromyc. Suaec. 69; Cooke, Fung. Brit. Exsicc.
96, 99; ed. 2, 288, 593, 594, 600; Vize. Fung. Brit. 95, 98;
Westend. Herb. Crypt. Belg. 120, 408, 553 (e only), 737, 830,
1389; de Thuem. Myc. univ. 156, *449, 1449, 1937,.2057 ;- Karst.

178 A MONOGRAPH OF THE ERYSIPHACECE

Fung. Fenn. Exsicc. 280, 368, 784 ; *Wartm. & Schenk, Schweiz.
Krypt. 524, 525,629; Wahrlich. Parasit. Pilz. 28, 29 (in Herb.
Hort. Imp. Petropol.); *Funck, Crypt. Gew. Fichtelgeb. 384 ;
*Erikss. Fung. par. scand. 38a, 38b, 148a, 236, 237, 340;
*Schmidt & Kunz. Deutschl. Schw. ccxxii.; Seym. & Earle, Econ.
Fung. 252; *Kneiff. & Hartm. Fl. Crypt. Bad. 159; *Krieg.
Fung. Saxon. 71, 822, 823, 824, 825, 827, 828, 829, 830, 831;
*Gandog. Fl. Alger. exsicc. 1980, 1983; *Ell. & Everh. Fung.
Columb. 614; *Cav. Fung. Long. exsicc. 118; Oudem. Fung.
Neerl. Exsicc. 73, 74, 155, 156, 157, 158; Zopf & Syd. Myc.
March. 52; Jack, Lein. & Stizenb. Krypt. Bad. 631, 632 ; Speg.
Dec. Myc. Ital. 84, 84bis ; Klotzsch, Herb. Myc. 61 ; and 65 sub
E. urticae ; and 1743, 1744 (Herb. Mus. Florence); Berk. Brit.
Fung. 200, 201, 203, 269 ; Baxt. Stirp. Crypt. Oxon. fasc. 2, 97 ;
Rab.-Wint. Fung. Eur. 3243 ; Kunze, Fung. select. exsicc. 60;
Erbar. Critt. Ital. ser. 1, 192 (in Herb. Mus. Florence);- Linhart,
Fung. hungar. 457 (in Iowa State College Herb.); Ell. & Everh.
N. Amer. Fung. 835, 2112, sec. ser. 3103.

Amphigenous ; mycelium very variable, persistent, thin, effused
and arachnoid or rarely thick, dense and lichenoid, or more often
completely evanescent; perithecia gregarious to scattered, rarely
densely gregarious, usually rather small, about 9o p, but varying
from 65-180 pin diameter, cells usually distinct, 10-15 p wide,
rarely 20 y wide ` appendages very variable in number and length,
sometimes few (3—7), distinct and long (10 times or more the di-
ameter of the perithecium), or more rarely few and short, usually
numerous and crowded, more or less densely interwoven, and long
or short, always spreading horizontally, often interwoven with the
mycelium, simple or rarely much branched, and then widely and
irregularly forking, sometimes angularly bent, or flexuose-con-
torted, colored dark or pale brown at the base or throughout, or
quite colorless, rarely becoming shining white, septate when col-
ored; asci usually few, 2-8, rarely as many as 22, variable in
shape and size, usually small and ovate, but varying from ovate to
broadly ovate or subglobose, with or without a short stalk, 46—72
(very rarely reaching to 80 DIN 30-45 ft; spores 3-8, usually
3-6, very rarely (and never uniformly), only 2, 19-25 x 9-14 f.

Hosts.— Achillea Ptarmica (350), Aconitum Anthora (341), A.
Fischeri, A. Napellus, A. paniculatum (176), Actaea spicata, Adonis
vernalis (22), Aegopodium Podograria (176) (230) (390), Aethusa
Cynapium, Ajuga reptans (353), Albizzia lophantha, Alnus incana,

ERYSIPHE 179

Alyssum calycinum, A. campestre (272), Amelanchier alnifolia
(200), A. maculatum (6), Amphicarpaea Edgeworthii, var. Japonica,
A. monoica, Anchusa officinalis, Anemone dichotoma, A. ranuncu-
loides (108), A. thalictroides (280), A. Virginiana, Angelica syl-
vestris, Anthriscus Cerefolium, A. sylvestris, Antirrhinum Orontium
(230), Aquilegia Canadensis, A. vulgaris, Arabis Turrita (230),
Archangelica officinalis, Arenaria decipiens, A. Juniperina (389),
Aristotelia racemosa, Asperula odorata (3), Aster commutatus (119),
Astragalus adsurgens, A. baeticus, A. caespitosus, A. Canadensis,
A. caryocarpus (60), A. decumbens (6), A. frigidus, var. Americanus,
A. Gebleri, A. glycyphyllosus (359) (390), A. Aypoglottis (6), A;
Junceus (363), A. Lamberti, A. multiflorus (6), A. oroboides and
var. Americanus, A. reflexistipulus, A. triphyllus (7) (60), A. vir-
gatus, Baptisia tinctoria, Brassica Rapa, B. Sinapistrum (56) (271),
B. sinapoides (214), Breynia acuminata, Calendula arvensis (55),
C. officinalis (22) (209), Caltha palustris, Calystegia sepium, Cam-
panula rapunculoides, Capsella Bursa-pastoris, Caragana arbo-
rescens, Carduus sp., Carum Persicum (233), Cassia Chamaecrista
(361), Catalpa syringaefolia, Caucalis Japonica, Centaurea scabiosa
(364), Chaerophyllum aromaticum, C. aureum, C. bulbosum (345)
(383), C. hirsutum, C. nodosum (383), C. temulum, C. Villarsti
(230), Chelone glabra (122), Cicuta virosa (319), Cimicifuga foetida
(347), Circaca Lutetiana, Clematis alpina, and var. Sibirica (341), É
Flammula (cult.), C. fusca, var. yezoeüsis, C. integrifolia (319), C.
leucantha (319), C. ligusticifolia (363), C. recta, C. Virginiana, C.
Vitalba, Cnicus lanceolatus, Colutea arborescens, Conium maculatum
(285) (319), Convolvulus Ammannü, C. arvensis, C. sagittatus,
Coronilla Emerus (285), C. varia (230), Crambe Sewerzowi (206),
Cucumis sativus (230), Cucurbita (39), C. Pepo (230) (319), Cuphea
viscossissima, Cytisus purpureus (378), Dahlia (cult.) (363), Daphne
alpina, Daucus grandiflorus, Delphinium Ajacis, D. azureum (263),
D. Consolida, D. elatum, D. formosum, D. grandifiorum (288), D.
orientale, D. tiroliense (230), D. vestitum, Desmanthus brachylobus
(cult.), Diervilla Japonica, Diplotaxis tenuifolia (214), Dipsacus `
laciniata, D. sylvestris (56) (133) (319) Draba hirta (60), Echium
vulgare, Elsholtzia cristata, Erectites pracalta~ (35), Eryngium
macrocalyx, Erysimum cheiranthöides (107), EF. odoratum (353),
Fagopyrum esculentum, Falcaria vulgaris, Falcata comosa (386),

180 A MONOGRAPH OF THE ERYSIPHACEAE

Galium (35) (394), G. Aparine (3) (56) (107) (133) (205*) (230)
(263) (290) (319), G. boreale (206) (359), G. Mollugo (133), G.
sylvaticum (3) (205*) (290) (391), Geranium dissectum (3), G.
maculatum, G. molle (263), G. pratense (107) (132) (133) (345),
G. pusillum (345), G. pyrenaicum (214), G. Richardsoni (60) (199),
G. sylvaticum (290), G. tuberosum (206), Geum urbanum, Gutier-
resia Euthamiae (199), Gypsophila Gmelini, Heracleum asperum
(cult.), Æ. flavescens (345), H. palmatum, H. Sibiricum, H. Sphon-
dylium, Hesperis matronalis, H. tristis (22), Heuchera Americana
(157*), Hosackia parviflora, Hyoscyamus niger (347), Hypericum
atomarium, H. hirsutum, H. montanum, H. perforatum, H. quad-
rangulum, Inula salicina (22) (348), [satis tinctoria (50), Johrenia
sp., Lactuca muralis (3), Lithospermum arvense ( 3), Lathyrus
Aphaca, L. montanus (115) (133) (311), L. Nessolia (263), L. pisi-
forms, L. polymorphus (363), L. polyphyllus, L. pratensis, L. tuber-
osus, L. uliginosus, L. venosus, Lespedeza striata (151), Zinaria
genistifolia (22), Liriodendron Tulipifera, Lotus corniculatus (383
and 384), Z. major, L. Purshiana, Lunaria rediviva (290), Lupinus
albus, L. angustifolius (319), L. argenteus var. argophyllus (363),
L. laxiflorus, L. luteus, L. parviflorus, L. perennis, L. sericeus,
Lychnis alba (319) (344), L. dioica, L. sylvestris (22), Lycopersicum
esculentum (342), Lycopsis arvensis, Lythrum Salicaria, Malcomia
maritima (56), Medicago falcata, M. lupulina, M. sativa, Melilotus
alba, M. officinalis, Myrrhis odorata, Oenothera albicaulis, O.
biennis, O. sinuata (12) (60), Onobrychis viciaefolia (22) (56)
(230) (290), Ononis arvensis, O. hircina (319), O. spinosa, Orobus
Lathyroides, Oxytropis Lamberti, Paconia obovata, P. officinalis, P.
peregrina, Parnassia Caroliniana, Pedicularis resupinata (309);
Peucedanum alsaticum (22), P. Cervaria (22) (377), P. oreoselinum,
P. sativum, P. terebinthaceum, Phaseolus helvolus (363), P. perennis
(60), Phloiodocarpus dahuricus, Physospermum commutatum, Picris
hieracioides ( 347), Pilea stipulosa, Pimpinella magna, P. Saxifraga,
Pisum sativum, Polygonum aviculare, P. dumetorum, P. lapathi-
folium, P. Persicaria (66), P. ramosissimum, and var. prolificum
(151), Potentilla (176), Prenanthes purpurea (133) (290), Psoralea
tenuiflora (60) (151), Quercus glauca, Ranunculus abortivus, R.
aconitifolius (290) (319) ( 364), R. acris, R. arvensis, R. Asiaticus
(354), R. bulbosus, R. Cymbalaria, R. Flammula, R. lanuginosus

ERYSIPHE 181

(176) (319), R. Lingua (318), R. macranthus (6), R. montanus, R.
multifidus, R. Pennsylvanicus, R. repens, R. sardous, R. sceleratus
(6) (199), R. septentrionalis (60), R. trachycarpus, Robinia Pseuda-
cacia (95) (319), R. viscosa, Rumex Acetosella, R. Hydrolapathum
(318), Saxifraga cortusaefolia, Scabiosa arvensis, S. stellata (50),
S. Succisa (107), S. sylvatica, Scandix Pecten- Veneris, Scutellaria
lateriflora (35) (386), S. scordüfolia, Selinum carvifolia, Sselie
(349), S. Libanotis (164*), Silaus flavescens (319), Silene noctiflora
(22), Siler trilobum (391), Sisymbrium alliaria (22), S. officinale
(56), S. Sophia, Sium erectum, S. latifolium (319), Smyrnium
olusatrum (18), Sonchus (172), S. arvensis (22), Spartium junceum
(272), Spiraea ulmaria, Statice Gmelini, S. Limonium, Symphytum
officinale (3), Teucrium Chamaedrys (20), Thalictrum angustifolium
(319), T. aquilegifolium, T. Cornuti, T. favum, T. minus and var.
elatum, T. simplex, Thermopsis montana, Thesium Bavaricum (378),
T. ebracteatum (107), Thlaspi arvense (310), Tragopogon (301),
Trifolium agrarium (290) (319) (384), T. alpestre, T. arvense, T.
filiforme, T. hybridum, T. incarnatum, T. involucratum, T. longipes,
T. Lupinaster, T. medium, T. minus, T. monanthum (60), T.
montanum, T. moranthum, T. pauciflorum, T. pratense, T. pro-
cumbens, T. repens (18) (290) (319), T. rubens, Trigonella cretica,
T. Foenum-graecum, Trollius Europaeus, Urtica cannabina, U. dioica,
U. urens (263), Valeriana capitata (206), V. officinalis (22) (107)
(132) (133) (192) (230) (319), Valerianella dentata (319), V. ri-
mosa (73*), Verbascum phlomoides (302), V. Thapsus (107) (263),
Verbena urticifolia (35), Veronica Teucrium (22), Vicia Americana
(60) and var. Zinearis (5) (6), V. cassubica (319) (359), V. Cracca,
V. Faba (214), V. gemella (383), V. hirsuta (38 3), V. oroboides, V.
pallida, V. sativa (107) (214) (260) (383) (384), V. sepium, V. syl-
vatica, V. unijuga, Vincetoxicum officinale (22) (344).

Distribution. —Evrore : Britain, France, Spain, Portugal (260)
(355), Belgium, Netherlands, Switzerland, Italy, Germany, Austria-
Hungary, Servia (318), Denmark, Norway, Sweden, Finland, Rus-
sia. ;

Arrica: Algeria, Canaries (253).

Asta: Turkey (Marash), Cyprus, Transcaucasia (338), Persia
(233) (389), Turkestan, Siberia (Minussinsk), Soongaria, India,
Japan.

182 A MONOGRAPH OF THE ERYSIPHACEAE

NEW ZEALAND.

AUSTRALIA : Victoria (225).

NORTH AMERICA : United States— Maine, Massachusetts, New
York, Pennsylvania, Maryland, New Jersey, Delaware, Virginia,
Carolina, Ohio, Michigan, Indiana, Alabama, Illinois, Mississippi,
Wisconsin, Missouri, Iowa, Minnesota, South Dakota, Nebraska,
Kansas, Montana, Idaho, Wyoming, Colorado, Utah, Nevada,
California, Washington ;—Canada, New Brunswick, Ontario, Mani-
toba.

E. polygoni (E. communis and E. Marti of most authors) is the
commonest and the most variable species of the Erysipl LAS
may be seen from the specific description given above, the present
species is variable in every character ; nature of the mycelium, size
of the perithecium, number, length, color, etc., of the appendages,
number of asci and spores. It may seem, at first sight, undesira-
bleto allow so wide a range of variation to a single species, yet
from the study of a very considerable amount of material it has
seemed to me impossible—so closely are the extreme forms linked
to the type—to separate any of these forms as varieties, much less
as species. Asa matter of fact, although several forms here in-
cluded under Æ. polygoni have been separated as distinct species,
E. polygoni itself has been frequently confused with E cichora-
cearum, as a glance at any large herbarium will show. Before
attempting to separate and give names to the most striking forms
of E polygoni, it seems to me wiser to collect the vast number of
forms of the two mildews (recorded as parasitic on no less than 602
species of plants) round the two specific centers here distinguished
as E. polygoni and E. cichoracearum.

Moreover the forms which have been hitherto separated from
E. polygoni as distinct species are certainly not satisfactorily defined.

E. Marti (E. pisi) still appears in many works as distinct from
E. polygoni, although the name appears practically to be one ap-
plied to examples of E. polygoni on certain host-plants quite as
much as to a form based on any morphological characters. Ori-
ginally, Æ. Martii was distinguished from — E. communis” by
Léveillé on the ground of possessing colorless appendages ; De
Bary, however, finding that this supposed character did not hold
good, united the two, and many subsequent authors followed this

ERYSIPHE 183

arrangement. Winter (394) and Schroeter (319), however, still
keep the two apart as distinct species, although both authors ad-
mit that, perhaps, the character of colored or colorless appendages
is variable. Asa matter of fact, as Burrill (60) has pointed out,
many of the specimens in the exsiccati quoted by Winter as be-
longing to Æ. Martii have distinctly colored appendages. An ex-
amination of specimens named E. Martii in herbaria shows at once
that in the forms of the present species, no satisfactory systematic
character exists in the absence or presence of color in the ap-
pendages, as a complete series of connecting links occurs, often,
even in specimens on the same plant, as may be seen in some ex-
amples on Lupinus. In many cases, though not in all, the ab-
sence of color is dependent merely on the age of the specimen as
at full maturity colorless appendages frequently become dark
brown. Æ. Marti, therefore, I think, may be safely considered a
synonym of the present species.

Oudemans (263) has attempted to separate certain forms of
E. polygoni by the number of spores in the ascus: Æ. umbelh-
ferarum on plants belonging to the Umbelliferae (e. g., An-
thriscus, Heracleum) is stated to have 3-4 spores; E. communts
and E Martii (on Polygonum, Hypericum, etc.), 4-8 spores. These
characters, however, altogether fail, and it need only be mentioned
that on Hypericum and Polygonum we quite commonly find asci
containing only 3 spores, while 3-6 spores occur frequently in
specimens on Heracleum, etc. It will certainly be admitted by
any one dealing with sufficient material of E polygoni that the
number of spores varies from 3-8 in this species.

E. umbelliferarum (E. heraclei) is generally separated, how-
ever, not by the number of spores, but by the shape of the conidia.
De Bary first pointed out this character when founding the species,
describing the conidia of £. communis as “ ellipsoidea” and those
of E. umbelliferarum (on Angelica, Chaerophyllum, Anthriscus,
Pastinaca, Falcaria and Heracleum) as “ exacte cylindrica” ;
further remarking “ dass diese Art £. umbelliferarum von E.
communis durch die Perithecien kaum verschieden ist. Dagegen ist
sie ausgezeichnet durch die Form: der Conidien, welche genau
walzenförmig, an beiden Enden flach, und mindestens (doch nicht
immer) sehr langgestreckt sind. Bei den vorher genannten Arten

184 A MONOGRAPH OF THE ERYSIPHACEAE

allen haben die Conidien die (im Profil elliptische) Gestalt einer
schmalen an den Enden abgerundeten Tonne."

Winter, Schroeter, and others, have followed De Bary in main-
taining Æ. umbelliferarum as a distinct species, confined to Umbelli-
ferae and distinguishable from Æ. polygoni (E. communis) only by the
shape of its conidia. I have, however, found generally in study-
ing specimens of Oidium in the fresh state that the shape (and size)
of the conidium is subject to so much variation that I am strongly
inclined to doubt the advisability of employing such characters for
systematic purposes, and especially of considering them of specific
importance. In the present case, although only examination of
living material of the forms on the different host-plants can satis-
factorily settle the whole question, it appears to me very doubtful
from the study of herbarium material, if the cylindrical form of
conidium is exclusively confined to examples on Umbelliferae and
whether conidia of both shapes do not occur in the same speci-
men. Certainly the conidia of E polygoni on some host-plants,
e. g., Clematis alpina, are more or less cylindrical. No differences
are to be found in the perithecial form of fruit of examples on
Umbelliferae to those of E polygoni on other hosts.

In dealing with the variation in mycelial characters we come
to two very interesting forms, viz, Æ. Ziriodendri Schwein and E
densa Berk.

E. liriodendri is maintained as a species by Burrill (60), who
remarks that it “ may be identified by its abundant, white myce-
lium, especially on the young stems."

I have examined many specimens of this form on Liriodendron,
and have found no characters except the persistent mycelium by
which it can be separated from typical E polygoni. When occur-
ring on the stems, E Ziriodendri has a thin persistent myce-
lium, but it is to be noted that on the leaves the mycelium is sub-
evanescent, and then the fungus cannot possibly be distinguished
from many of the forms of E polygont on other hosts. Nor can
the persistent mycelium on the stem be considered absolutely pe-
culiar to the form on Liriodendron; in the herbarium of the Up-
sala Museum there is a specimen of E polygoni on the stems of
Thalictrum aquilegifolium in which the mycelium is persistent, and
in some places almost pannose in consistency. This specimen

ERYSIPHE 185

forms a quite similar state to that of Æ. Zriedemdri and more-
over quite commonly on Thalictrum minus, Polygonum aviculare,
etc. E. polygoni shows a tendency towards developing a persistent
mycelium.

More marked than Æ. “irtodendri is a form on Diervilla
Japonica from Sapporo, Japan (K. Miyabe and N. Hiratsuka) sent
to me by Professor Miyabe under the mss. name of Zrysiphe
diervillae, with these notes, “ E diervillae ripens its perithecia only
in the early spring of the next year. Mycelial layers are formed
on the young branches and persistent capsules. Perithecia 120-
135 u, asci 37-45 x 67-86, ascopores (6-7) 11 x 224.” This
form on Diervilla covers the stem and fruit of the host-plant with
soft dense patches of persistent mycelium, in which the perithecia
are more or less imbedded. Except in these characters, however,
the fungus is not different from Æ. polygoni, and it is to be noticed
that here and there on the stem, perithecia occur from which the
mycelium has almost or quite disappeared, and so are more or less
naked as in ordinary Æ. polygoni.

Even more striking is the plant published by Berkeley as
Erysiphe densa, on Aristotelia racemosa from New Zealand.
Berkeley remarked : “ This differs from Æ. Marti Lév. merely in
its thick persistent mycelium, which gives it a very lichenoid ap-
pearance, especially when on the upper surface of the leaf." . There
is a fine series of “ E densa” in the Kew Herbarium, and the
specimens show in a very clear manner how variable the nature of
the mycelium is in the present species, even on the same host-
plant. In this series, the mycelium on most of the leaves is very
dense and compact, more or less thick, and lichenoid, either
limited to spots or extending more or less completely over the
whole upper surface of the leaf. The fungus in this condition
seems quite distinct from E. polygoni, in which a persistent lichen-
oid mycelium has not been recorded on any host. On other
leaves of Aristotelia in this series, however, we find only a thin
layer of persistent mycelium, from arachnoid to merely pruinose
in consistency. Finally, on some leaves we find an absolutely
evanescent mycelium. I can find no difference in the perithecia
from those of E. polygoni, and under the circumstanees, consider-
ing the variable nature of the mycelium, I do not think E

186 A MONOGRAPH OF THE ERYSIPHACEAE

densa—although so marked in its extreme state—can be given
even a varietal rank. Nothing can be more marked, at first sight,
than the forms of Æ. taurica with persistent densely compacted
mycelium, yet we find that this species may not uncommonly occur
with an evanescent mycelium ; in the same way we must, it seems
to me, considering the evidence afforded by the forms on Lirio-
dendron, Diervilla and Aristotelia, allow to E polygoni a similar
range of variation in mycelial characters.

Karsten, in the second part of Myc. Fenn. has described a
species of Erysiphe as follows : “E. vernalis Karst. Mycelium arach-
noideum, saepissime evanidum. Asci in quovis perithecio 8
ovoideo-sphaeroidei, breviter pedicellati 8-spori. Appendiculae
sat longae, cum mycelio intertextae. Hab. In ramulis vivis
Alni incanae fine mensis Maji ad Mustiala semel observata.
A sequente [Z. Martii Lév.] fort: non distincta." In the No-
tiser ur Sallsk. Faun. Fl. Fenn. Fórh. 13: 247 the following
further description is given, “ Perithecia hemisphaerica, mycelio
emersa, fusca, latit. circiter 0.1 mm. Asci 8ni. brevissime pedicel-
lati, ovoidei- vel oblongato-sphaeroidei, longit. circit. 69 mmm.,
crassit, circit. 39 mmm. Sporae 8nae, sphaeroideo-ellipsoideae,
longit. 16-18 mmm., crassit. 11-12 mmm. Appendiculae hy-
alinae. . . . Species quasi media inter Erys. graminis et Erys.
Martii."

Professor Karsten has kindly sent me specimens (now in the
Kew Herbarium) of £. vernalis, and after a careful study of the
plant and comparison of it with numerous forms of E polygoni, I
do not see by what characters it can be separated from this spe-
cies. Itis, nevertheless, a rather marked and extremely interest-
ing form. The fungus occurs on the young shoots of A/nus incana ;
the mycelium is more or less evanescent on the internodes, and the
perithecia are here scattered, but at the base of the buds the perithecia
become gregarious, and the mycelium is persistent. The perithecia
average about 120 p in diameter, and the appendages are rather
long, not much interwoven, hyaline and quite similar in every way
to those of many forms of E polygoni. The asci are usually rather
numerous, sometimes as many as 15, and may reach to 80 pin
length ; in shape they are usually broadly-ovate to ovate-oblong ;
very rarely, however, they show a tendency to become subcylin-

ERYSIPHE 187

drical, the 7-8 spores measure about 18x 12 y. Many forms of
E. polygoni approach so closely to all the above characters (this is
the case, e. g., with the form of Albizzia (Acacia) called by Eriks-
son Æ. Martii forma acaciae) that it seems impossible to separate Æ.
vernalis from them. On the other hand, Æ. vernalis, shows
undoubted affinity with the American species Æ. aggregata
on alder-catkins. ` E vernalis has smaller perithecia, fewer,
smaller, less cylindrical asci, and less interwoven appendages ; oc-
casionally, however, the asci show a tendency to become sub-
cylindrical and the roundish spores are the same in both plants.
It is possible that, if more intermediates occur, Æ. aggregata may
have to be regarded as only a well marked variaty of Æ. polygoni.

Magnus has considered the fungus growing on Caragana arbo-
rescens and Colutea arborescens as belonging to the genus Micro-
sphaera, and has published it as a new species, M. caraganae. I
had already seen specimens of this plant on Co/utea in Syd. Myc.
March. 980, and on Caragaza in Syd. Myc. March. 3718, and had
referred them to E. polygoni. Professor Magnus has kindly sent
me very beautiful specimens (now in the Kew Herbarium) of
« Microsphaera caraganae, on Caragana arborescens Wannsee,”
and after examining these I still feel convinced that the fungus is
nothing but a form of Erysiphe polygoni. . None of the specimens
possess appendages with apical branching of the definite type found
in Microsphaera ; as a rule, the appendages are unbranched, and
the branching that does occasionally occur is always quite vague.
The appendages are usually about 9 in number, rather distant from
one another, septate, and more or less colored towards the base.
Occasionally the appendages are as few as four, and the coloring
extends almost to the apex. A few perithecia were observed in
which the appendages, 4 or 5 in number, were stouter than usual,
rounded at the end, and colored deep brown throughout —much
recalling the American form of E polygoni on Parnassia mentioned
below. As Magnus points out, there appear often among the
normal appendages very short rudimentary ones. This character,
however, as well as that of the few and distant appendages, can
be in no way considered peculiar to the form on Caragana and
Colutea, as both are found in many common forms of undoubted
E. polygoni. In the present form the appendages become more

188 A MONOGRAPH OF THE ERYSIPHACEAE

free from the mycelium than is usually the case, and, as the peri-
thecia are often densely gregarious, give a slightly floccose appear-
ance to the leaf. This habit (which is found in some species of
Microsphaera), however, is not confined to the plant on Caragana
and Colutea, as in the forms of E. polygoni on Lupinus (European
and American) exactly the same appearance is found.

A very striking form of Æ. polygoni occurs in America on
Parnassia Caroliniana. I have seen two specimens of this, one from
Madison, Wisconsin (Halsted and Tracy, August, 1893), ex herb.
S. M. Tracy (in the Herbarium of the Missouri Bot. Garden),
where the fungus is labelled ** Evysiphe spatulata”; the other from
Syracuse, New York (L. M. Underwood, July, 1899), named
Erysiphe communis. The striking feature of this form is the pres-
ence of few, brown, usually short, stout, rigid appendages. The
perithecia are 70-85 in diameter, the asci 3-6, 50-58 x 30-36 p,
spores 3-5, very rarely 2,20 x 104. Except in the appendages,
the fungus agrees well with certain common forms of £. polygoni.
In the Wisconsin specimen the appendages give a very distinct ap-
pearance to the form ; they are usually few and very short, in fact
often rudimentary and only about a quarter of the diameter of the
perithecium in length, very stout (about 10 u wide), and dark
brown throughout ; in the New York specimens, however, most
of the perithecia have longer appendages, 3—4 times, or more, the
diameter of the appendages, paler towards the apex, and 7-8
# wide, and it is then at once seen that the present plant is closely
connected with many forms of Æ. polygoni on various host-plants,
€. g., Some specimens on species of Clematis and on Caragana
arborescens are very similar. On the whole, I am inclined to re-
gard the fungus on Parnassia rather as a starved form of E. poly-
gont, caused perhaps by growing on an unsuitable host-plant

as a true variety.

(Since the above remarks were written, Halsted (157*) has
founded a new genus, Erysiphopsis, on this fungus on Parnassia
Caroliniana. Y am quite unable to follow this treatment. Any
one at all acquainted with the forms of Erysiphe polygoni will, I
think, at once admit that the füngus in question clearly belongs to
the genus Erysiphe, and is, moreover, I believe, so close to certain
forms of this species that (as mentioned above) it seems doubtful
if it can be separated even as a variety.)

ERYSIPHE 189

The plant issued as “ var. de/phinü” (on stems of Delphinium)
Ell & Everh. N. A. Fung. no. 835 does not differ from many
common forms of Æ. polygoni, and cannot be separated from the
type.

An interesting Erysiphe has been sent to me by Professor Mi-
yabe from Japan (Kyoto, April, 1899, coll. T. Nishida), growing
on Quercus glauca, which I cannot separate from Æ. polygoni. This
form has a rather distinct habit ; the persistent, thin, subcrustace-
ous mycelium forms definite patches on the upper surface of the
leaf, and on these the perithecia are more or less gregarious. The
diameter of the perithecium is about 90 7 ; the asci are 4-6, ovate to
ovate-oblong, often without a stalk, 50-58 x 30-35 #, spores 4-6,
21x10 p. The appendages are from 2 to 3 times the diameter of
the perithecium, rather numerous but distinct, colorless, becoming
shining, and are more or less irregularly bent, or geniculate, at in-
tervals. Except in the rather marked habit, the fungus does not
differ in any way from many common forms of Æ. polygoni. This
is the first record of the occurrence of an Zrysiphe on Quercus in
the Old World. The Californian Æ. trina on Quercus agrıfolia is
quite distinct from the present form.

The record of Æ. Martii by Cooke (83) on Populus ciliata
is an error, the fungus being Uxcinula salicis. The specimens
published as Æ. Marti in Rab. Fung. Eur. 1737, on Rudia perc-
grina, and in Roumeg. Fung. Gall. nr. 3316 on Asperula odorata
are some sphaeriaceous fungus.

E. polygoni is the cause of the disease known as the “ blight ”
or “ mildew ” of several cultivated plants of economic importance.

In the first place, it causes the “bean” and “pea blight,”
well known to market gardeners. Bessey (40), speaking of this
disease in the United States, says, ‘‘ pea blight has for many years
been very destructive to late peas in the West; it has, in fact,
rendered the growth of the later varieties in some instances al-
most impossible.” As regards remedies against the disease, Gal-
loway (135) mentions a case where a crop of beans badly mil-
dewed was “thoroughly dusted with flowers of sulphur, and in a
week the fungus had entirely disappeared, and the plants produced
a good crop.” The following advice is given: “A powder made
by mixing equal parts of air-slacked lime and flowers of sulphur

190 A MONOGRAPH OF THE ERYSIPHACEAE

will be found a very good remedy. The powder should be dusted
on the foliage at the first appearance of mildew and the operation
repeated every ten or twelve days, or more often if there is an
abundance of rain. If one has a spraying machine, a solution
made by dissolving 3 ounces of carbonate of copper in 2 quarts
ef aqua ammonia diluted to 22 gallons will be found an efficient
remedy. This solution should be applied every twelve or fifteen
days, beginning at the first appearance of the disease.”

The “mildew of turnips” is also caused by Æ. polygoni.
Hitherto the fungus causing this disease has been known only in
its conidial stage, and has been wrongly identified as Oidium Bal-
samit (Mont. mss.) Berk. & Broome. Worthington G. Smith
(329, p. 76) first gave it this name, and described the disease as
follows: “ Ozdium Balsamii, Mont., first attracted attention as a
pest of turnips in September, 1880, when Prof. James Buckman,
F.L.S., of Bradford Abbas, Dorsetshire, saw the fungus grow-
ing in such profusion over hundreds of acres of Swede turnips
that the boots and clothes of persons walking through the turnip
fields were whitened with the spores. Until 1880 the fungus was
not supposed to be common in Britain. . . . Important as this
Oidium is to agriculturists, no one at present has worked out its
life-history, or knows whence it comes, where it goes, what other
form it takes, or how it hibernates through the winter. The fun-
gus is more prevalent when a humid September follows on a dry
August." Trail (365) notices the disease, and says of “Oidium
Balsamii,” “ It is of considerable practical interest, since it attacks
various cultivated plants. Near Aberdeen [Scotland] I have seen
it in great plenty upon turnips, preferring the Swedish to the com-
mon yellow turnip.”

In the beginning of November, 1898, my attention was di-
rected to some fields of turnips, near Reigate, Surrey, England,
which were, in places, quite white with mildew. On examination
it was found that this appearance was caused by the presence of
an Odium, which agreed with specimens in the Kew Herbarium
named QO. Balsamii, on turnips, by Worthington G. Smith. 0.
Balsami (Mont. mss.) is thus described by Berkeley and Broome
(38): “ Candida, articulis doliiformibus utrinque angustatis. On
the leaves of Verbascum nigrum, Wothorpe, Aug. 23, 1853. This

ERYSIPHE 191

species was sent from Milan by Balsamo to Dr. Montagne, under
the name of Oidium Tuckeri, but it is a very different species, dis-
tinguished by the very peculiar shape of its spores. The length
about .oo15. Balsamo’s plant grew on Verbascum montanum.
No Erysiphe has at present been observed in connection with this
species. The same species occurs on strawberries, to which it is
very destructive. See Gard. Chron., April 15, 1854."

In Berkeley’s herbarium at Kew there is the specimen of O.
Balsamii from Montagne’s herbarium referred to above, and the
conidia here are more or less barrel-shaped, ranging from 28-30
x 14-18 win size (Fig. 161). In the turnip mildew the conidia
are subcylindrical, with rounded, unconstricted ends, 30-40 x 13-
15 7, produced singly on the conidiophores (Fig. 162). Probably
O. Balsamit on species of Verbascum is the conidial stage of
Erysiphe cichoracearum or E. taurica ; the Oidium on strawberries is
probably that of Sphaerotheca humuli.

After a careful search on the Ozdium-infected turnips, referred
to above, I found on a few plants some scattered patches of the
perithecia of Zrysiphe polygoni. These perithecia occurred chiefly
on the stem and petioles, only very rarely on the leaves. The
perithecia are mostly gregarious in scattered patches among the
subpersistent mycelium and contain about 6 asci, with 4-5 spores.
The appendages are colorless, or occasionally one here and there
is colored, and are variable in number and length, usually about
2-4 times the diameter of the perithecium. The turnip crop was
very poor, but as the plants were infested with “ green-fly” (Ap/u-
des), it is impossible to say to what extent the inquiry was caused
by the fungus alone. The remedies given above for the “ pea
blight” would probably be equally efficacious here.

— Var. sepulta (Ell. & Everh.). [Fig. 157]

Erysiphe sepulta Ell. & Everh. Bot. Gaz. 14: 286. 1889.

E. cichoracearum DC. Burr.; Ell. & Everh. N. Amer. Pyren.
12 (form on Bigelovia graveolens only). 1892 ; Jones, Proc. Calif.
Acad. Sci. Il. 5: 731. 1895:

Amphigenous; mycelium evanescent or subpersistent ; peri-
thecia large, 140-220 p in diameter, averaging 180 p, cells indis-
tinct ; appendages numerous, rather short, delicate, colorless, hya-

192 A MONOGRAPH OF THE ERYSIPHACEAE

line, densely interwoven ; asci very numerous, from 20 to 34, or
more, large, broadly ovate-oblong to subcylindrical or subpyri-
form, 70-100, usually about 85, x 30-36 p, usually stalked;
spores 4-6, 20-22 x 10-12 H.

Host.—Bigelovia graveolens and var. albicaulis.

Distribution.—NortH AMERICA: United States ;——Montana,
Wyoming, Colorado, Utah (179).

Two forms of Erysiphe occur on species of Bigelovia (B. grave-
olens) and its var. albicaulis, and B. viscidiflora(B. Douglasii) in the
United States. The Zrysiphe on B. viscidiflora has regularly bi-
sporous asci, and although a marked form from its large size must
be referred to E. cichoracearum, as has already been done by Ameri-
can mycologists. The Erysiphe on B. graveolens is very different.
The perithecia, which occur in scattered patches on the stem, are
at first more or less immersed and firmly imbedded in the pannose
tomentum of the host-plant; at maturity, however, the perithecia
break through the tomentum of the stem, and appear in naked
black patches. The perithecia are, as a rule, very large, and con-
tains a great number of asci. The asci are large, rather irregular in
shape, sometimes subcylindrical or somewhat pyriform, and con-
tain constantly 4-6 spores, are about 22x11 on in size. These
characters give the plant, in my opinion, a position somewhat in-
termediate between Æ. polygoni and E aggregata ; from the former
it differs in the larger size, and larger and more numerous asci,
from the latter in the more interwoven appendages and 4-6 longer
spores. American mycologists have placed this form in Æ. cicho-
racearum, merely for the reason, it appears that, as mentioned
above, on another species of Bigelovia (B. viscidiffora), E. cichora-
cearum, with its normal bisporous asci, is found. We must re-
member, however, that many cases occur in which distinct species
of the Erysiphaceae are found on even the same species of host-
plant, and very commonly we find two or more species of mildew
on different species of host-plants belonging to the same genus.

The name Æ. sepulta was published in the Bot. Gazette, 14:
286. 1889, as follows: “ Erysiphe sepulta Ell. & Everh. n. sp.
This species is so named only provisionally, and may yet prove to
be only an old species under peculiar circumstances. . . It comes
so near to È. cichoracearum that it may well be doubted if it be a
new species; but the perithecia appear imbedded in the woolly

ERYSIPHE 193

coat of the host." Burrill (60), in his description of Æ. cichora-
cearum says: “ Sporidia large, quite uniformly 2, but occasionally
varying to 3 or even 4” (on Bigelovia 5 or 6), and, under the same
` species, adds the further remarks. “ A form on Ligelovia graveo-
lens has 20-30 asci, many of which have 3-5, and perhaps more,
sporidia, and the appendages are short and almost hyaline. Taken
by itself, it could hardly be admitted as belonging to the present
species. Ellis and Everhart provisionally propose the name £.
sepulta for it. But on Bigelovia Douglasii, growing with the pre-
ceding, the fungus is in all characteristics the same, except that
the sporidia are uniformly 2, in the specimens examined, and so re-
ported by others. The asci are often as many as 30 in both cases,
a number much greater than commonly given for typical Æ.
cichoracearum. On other host species the number of asci is ex-
ceedingly variable, mostly only 4-8, but in some collections east
of the Mississippi river reaching 20, with apparently no way of
distinguishing different species among the variable forms. Those
on Bigelovia are indeed further aberrant, but it does not seem
wise to separate one or both as specifically distinct, either from
each other, or from those with which they are undoubtedly allied
on the host-plants enumerated above.”

Jones (179), in * E. cichoracearum” on Bigelovia graveolens
from Utah, remarks: “asci numerous, 15-20 or more ; sporidia
uniformly 4—6, much smaller than in the type. . . The characters
given above would suggest a relationship to E. communis rather
than to E cichoracearum, but no forms of that species have so far
been reported on Compositae.”

It may, however, be pointed out that, among Compositae, a
form of Æ. polygoni occurs on the stem of species of Carduus and
Cnicus, which although very unlike the var. sepulta in its small
size, yet approaches it in possessing numerous asci (23 or more).
The form of E polygoni described as Æ. vernalis, also, must
be considered in dealing with the question of the position of the

present plant.
2. E. cıcHorACEARUM DC. [Figs. 140, 151]

Mucor Erysiphe Leyss. Fl. Hal. 305. 1783.
Erysiphe cichoracearum DC. Fl Er 22.274.: 1806 ; Wint. ;

194 A MONOGRAPH oF THE ERYSIPHACEAE

Rabenh. Krypt. Fl. Deutschl. 17: 33. 1884; Karst. Act. Soc.
Faun. Fl Fenn. 2: 94. 1885; Burr. & Earle, Bull. Ill. State
Lab. Nat. Hist. 2: 404. f. 4 (excl. syn. E sepulta) 1887; At-
kins. Journ. Elisha Mitch. Sci. Soc. 4:065. 1891; Burr.; El.-&
Everh. N. Amer. Pyren. 12 (excl. syn. Z. sepulta). 1892.

E. varium Fr. Obs. Myc. 1: 206 (partim). 1815; 2: 366
(partim). 1818.

Alphitomorpha communis, var. cichoracearum Wallr. Berl.
Ges. Nat. Freund. Verh. 1 : 31. I819.

A. depressa Wallr. Berl. Ges. Nat. F reund.: Verh; 1:34.
1819; Wallr. Fl. Crypt. Germ. 2: 25% 1833.

A. circumfusa Schlecht. Berl. Ges. Nat. Freund. Verh. I: 49.
1819.

A. bardanae Wallr. Ann. Wett. Ges. 4:239. 1819.

A. cynoglossi Wallr. Ann. Wett. Ges. 4:240. 1819.

A. artemisiae Wallr. Ann. Wett. Ges. 4:240. 1819.

Erysibe biocellata Ehrenb. N. Act. Acad. Leop. Car. Nat. Cur.
TO: 211.2. 73. 1821; Lk: Willd. Sp. PL 6: 109. 1824.

E. depressa, var. artemisiae Wallr, Ficin. & Schub. Fl. Gegend.
Dresd. 2: xix. 1823.

E. communis Schlecht. Fl. Berol 2: 168. 1824; Rabenh.
Deutschl. Krypt. Fl. 1 : 232 (partim). 1844.

E. circumfusa Schlecht. Fl. Berol. 2: 169. 1824; Lk.; Willd.
Sp. Pl. 6: 109. 1824; Rabenh. Deutschl. Krypt. Fl. r: 232
(partim). 1844.

E. depressa Schlecht. Fl. Berol. 2: 169. 1824; Lk.; Willd.
Pl. 6: 110. 1824; Rabenh. Deutschl. Krypt. Fl. 1: 232 (par-
tim). 1844.

E. communis, var. cichoracearum Lk.; Willd. SR PL 06: 107.
1824.

. lamprocarpa, var. plantaginis Lk.; Willd. 5511. 6:109.
1824.
Erysiphe artemisiae Grev. Fl. Edin. 459. 1824.

E. arctii Grev. Fl. Edin. 460. 1824.

E. asperifoliorum Grev. Fl. Edin. 461 (partim). 1824.

E. bardanae Chev. Fl. Par. 1: 381. 1826.

E. communis Fr. Syst. Myc. 3: 239 (partim). 1829; Berk.;
Sm. Eng. Fl. 5: 325 (partim). 1836,

ERYSIPHE 195

E. communis, var. cichoracearum Duby, Bot. Gall. 2: 869.

1830.

A. lamprocarpa, var. plantaginis Duby, Bot. Gall. 2: 869.
1830.

E. compositarum Duby, Bot. Gall. 2 : 870 (excl. var. cyzarae).
1830.

E. knantiae Duby, Bot. Gall. 2: 870. 1830.

Alphitomorpha horridula Wallr. Fl. Crypt. Germ. 2: 755
(partim). 1833.

A. lamprocarpa, var. plantaginis Wallr. Fl. Crypt. Germ. 2:
758. 1833.

A. communis Wallr. Fl. Crypt. Germ. 2: 758 (partim).
1833.
Erysiphe ambrosiae Schwein. Syn. Fung. Am. Bor. 270. 1834;
Sacc. Syll. Fung. 1: 22. 1882.

E. verbenae bane Syn. Fung. Am. Bor. 270. 1834 ; Sacc.
Syll. Fung. 1: 22. 1882.

^ E. phlogis "ee Syn. Fung. Am. Bor. 270. 1834 ; Sacc.
Syll Fung. 1:21. 1882.

E. asterum Schwein. Syn. Fung. Am. Bor. 270. 1834 ; Sacc.
Syll. Fung. 1:23. 1882.

Erysibe lamprocarpa Rabenh. Deutschl. Krypt. Fl. 1: 232
(partim). 1844.

E. horridula Rabenh. Deutschl. Krypt. Fl. 1:235 (partim).
1844.

Erysiphe scorzonerae Cast. Cat. Pl. Mars. 189. 1845.

E. lamprocarpa Kickx. Fl. Crypt. Env. Louv. 140 (partim).
1835; Dur. & Mont. Fl. d’Algér (Crypt.) 567. 1846-9; Lev.
Ann. sci. nat. III. 15 : 163. $4 zo. f. 31 (partim). 1851; Cooke,
Micr. Fung. 220. pl. r2. f. 250, 257. 1865; de Bary, Beitr.
Morph. Phys. Pilz. 1: § xiii. 49. 1870; Cooke, Handb. Brit.
Fung. 2: 650. f. 317. 1871; Karst. Myc. Fenn. 192 (partim).
1873 ; Sacc. Syll. Fung. 1 : 16. 1882; Jacz. Bull. l Herb. Boiss.
4:730. 1896; Oudem. Rév. Champ. Pays.-Bas. 2:94. 1897.

E. orontii Cast. Supp. Cat. Pl. Mars. 52. 1851.

E. linkii Lev. Ann. sci. nat. III. 15: 161. M. ro. f. 20. 1851;
Cooke, Micr. Fung. 220. fl. 72. f. 248, 249. 1865 ; Cooke,
Handb. Brit. Fung. 2: 650. 1871; Karst. Myc. Fenn. 2: 191.

196 A MONOGRAPH OF THE ERYSIPHACEAE

1873 ; Sacc. Syll. Fung. 1 : 16. 1882; Wint.; Rabenh. Krypt.
Fl. Deutschl. 1: 30. 1884; Karst. Act. Soc. Faun. Fl. Fenn.
2:92. 1885; Jacz. Bull. l Herb. Boiss. 4 : 727. 1896 ; Oudem.
Rev. Champ. Pays.-Bas. 2:93. 1897.

E. Montagnei Lév. Ann. sci. nat. III. 15: 169. pl. rr. f. 36
(excl. syn. E lappae Cast) 1851; Cooke, Micr. Fung. 220
. (excl. syn. E. compositarum, var. cynarae). : 1865; Cooke, Handb.
Brit. Fung. 2: 651. 1871; Sacc. Syll. Fung. 1: 17. 1882.

E. horridula Lév. Ann. sci. nat. III. 15: 1720: Pl. In fo 37.
1851; Cooke, Journ. of Bot. 4: 98. 1866; Cooke, Handb.
Brit. Fung. 2: 652. 1871; Karst. Myc. Fenn. 2: 194. 1873;
Sacc. Syll. Fung. 1: 17. 1882; Oudem. Rev. Champ. Pays.-
Bas. 2: 96. 1897.

Uncinula adunca, var. artemisiae Prod. Fl. Bat. 2: 33. 1866.

Erysiphe spadicea Berk. & Curt* Grevillea, Tva ee VAE
Sacc. Syll. Fung. 1: 18. 1882.

E. horridula, var. cynoglossi Sorok. 147. M. 88 (13). f. 191—194.
1889. f
E. lamprocarpa, var. plantaginis Sorok. Rev. Myc. 148. ai 89.
(75). f. 240. 1889.

Erysibe cichoracearum DC. Schroet.; Cohn’s Krypt. Fl. Schles.
3: 238. 1893.

Exsicc.: Westend. Herb. Crypt. Belg. 226, 409, 410, 411,
553 (f only), 1058; Rab, Fung. Eur. 561, 673, 1059, 1067,
1149, 1325, 1523, 2320, 2520; Rab. Herb. Myc. ed. 2, 470,471,
*485, 486, *669 ; Desmaz. Pl. Cr. Fr. ed. I ser 1,405, 518,
1108 (B only), 1109 (A only), 1304 (A only), 1516, 1517; *ed.
2, ser. I, III, 508 (B only), 814, 1016, 1017 ; de Thüm.; Fung.
austr. 237, 452, 456, 754, 856, 1043, 1144, *1145, 1247, 1250;
de Thuem. Myc. univ. 55, 449, 1353, 1840; *de Thuem. Fung.
exot. dec. 32, 34; Oudem. Fung. Neerl. Exsicc. 75, 76, 260;
Roumeg. Fung. Gall. exsicc. 2339, 3738 ; Roumeg. Fung. Sel.
Gall. Exsicc. 261, 533 ; Fckl. Fung. Rhen. 648, 650, 652, 653,
655, 657, 658, 670, 673, 674, 688, 1567, 1739, 1740: *Seym. &.
Earle, Econ. Fung. 46, 293a and b, 295a and b, 305, 321, 346 ;
"EIL & Everh. Fung. Columb. 312, 313, 613 ; Syd. Myc. March.
652, 656, 840, 1145, 1146, *1147, 1148, 2326, 2327, 2766, 3051,
3460, *3918, *4015 ; *Gandog. Fl. Alger. Exsicc. 1981 ; Sacc.

ERYSIPHE 197

Myc. Ven. 608, 904; Bri. & Cav. Fung. par. 263, 264; Rehm.
Ascom. 396, 397; Cooke, Fung. Brit. Exsicc. 97, 199, *200,
466 ; ed. 2, 285, 287; Vize. Fung. Brit. 96, 199; Ayres. Myc.
Brit. 77 ; *Erikss. Fung. Par. Scand. 37a, 146, 147a and b, 148b,
289, 339; *Fl. Exsicc. Austr.-Hungar. 1173; Ell. & Everh. N.
Amer. Fung. 2916, 3006 ; Rav. Fung. Car. Exsicc. 69 ; *Kneiff.
& Hartm. Pl. Crypt. Bad. 13, 161 ; Wahrlich, Parasit. Pilz. 25, 26,
27 (in Herb. Hort. Imp. Petropol); Lib. Pl. Cr. Ard. 183 (in
Herb. Jarb. Bot. Bruxelles).

Sub Zrysiphe polygoni ; Rab. Fung. Eur. 1066, 1742, 1917;
+Desmaz. PL Cr. Br. ed. 1, set. 1, 1108B, éd... 2, sér. 1. 509A;
*Krieg. Fung. Saxon. 826; Syd. Myc. March. 1144; *Karst.
Fung. Fenn. 785; Berk. Brit. Fung. 202; Klotsch. Herb. Myc.
60; Westend. Herb. Crypt. Belg. 1058; Roumeg. Fung. Gall.
Exsicc. 2271; de Thüm. Fung. austr. 1250; Fckl. Fung. Rhen.
670.

Sub E taurica; Roumeg. Fung. Sel. Exsicc. 4564.

Sub Sphaerotheca Castagnet; Rab. Fung. Eur. 1048, 1051,
1916; de Thuem. Fung. austr. 441; Cooke, Fung. Brit. Exsicc.
ed. 2, 591, 592; Sacc. Myc. Ven. 630.

Sub Erysiphe galeopsidis ; Westend. Herb. Crypt. Belg. 409;
Desmaz. Pl. Cr. Fr. ser. 1, 1517.

Amphigenous; mycelium usually evanescent, sometimes per-
sistent and effused, usually white, rarely with a pinkish tinge;
perithecia sub-globose or globose-depressed, often becoming con-
cave, gregarious or scattered, 80-140 nu in diameter, very rarely
140-180 u, cells variable in size, often very distinct, and 10-20 #
wide, sometimes smaller, 10 # wide, and obscure; appendages
very variable, long or short, brown or sometimes colorless, usually
numerous, densely interwoven, vaguely branched, septate, light or
dark-brown throughout, and from 2-4 times the diameter of the
perithecium, but sometimes very few, and short or even rudi-
mentary ; asci usually numerous, about 10-15, but varying from
4-25, very rarely as many as 36, variable in size and shape, from
narrowly ovate or subcylindrical to broadly ovate, or rarely sub-
globose, more or less stalked, 58-90 x 30-50 #4; spores 2, rarely
(and never uniformly) 3, 20-28 x 12-20 p, usually about 24 x
14 p.

: ac s Millefolium, A. Ptarmica, Actinomeris squar-
rosa, Adenostyles alpina (3), A. viridis, Ambrosia artemisifolia, A.

198 A MONOGRAPH OF THE ERYSIPHACEAE

psilostachya, A. trifida and var. integrifolia, Amsinckia spectabilis, An-
chusa Italica (56), A. officinalis (22) (107) (229) (319) (345), Antır-
rhinum Orontium, Aplopappus sp., Apocynum (84), Arctium majus,
A. minus, A. nemorosum, Artemisia Absinthium, A. biennis (60), A:
campestris, A. discolor (6), A. dracunculoides, A. glauca, A. Japon-
ica, A. Ludoviciana, var. guapolodes, A. vulgaris, Asclepias variegata,
Asperugo procumbens, Asperula odorata (176), Aster adscendens (6),
A. canescens, A. communis, A. commutatus, A. conspicuus (6), A.
cordifolius, A. corymbosus (363), A. diffusus (10) (12) (265), A.
Drummondi (265), A. ericoides and var. villosus (324), A. foliaceus,
var. Eaton, A. Fremonti, A. grandiflorus (2 39), A. junceus (265),
A. laevis and var. laevigatum, A. longifolius, A. macrophyllus (61),
A. multiflorus (6), A. oblongifolius (61), A. paniculatus, A. prenan-
thoides, A. puniceus, A. sagittifolius, A. salicifolius (60), A. Shortü
(324), A. Tradescanti, A. umbellatus (60), A. vimineus, var. foli-
olosus (61), Ballota nigra (263), Balsamorhiza sagittata, Boltonia
asteroides, Bigelovia viscidiflora, Borago officinalis, Calendula off-
cinalis (205*), Campanula sp. (347), C. glomerata (235), Carda-
mine sp., Carduus acanthoides, C. tenuiflorus (56), C. viridis (230),
Carlina acaulis (20) (272) (319), Centaurea Jacea (3) (290) (319)
(345), C. nigra, C. nigrescens, C. scabiosa, Cerinthe minor (22),
Chrysopsis villosa, Cichorium Intybus, Clematis orientalis (206),
C. altissimus and var. discolor, C. arvensis (319), C. cardun-
culus (214), C. eriophorus, C. heterophyllus, C. lanceolatus, C.
oleraceus, C. rivularis (319), C. undulatus, var. canescens, Cousina
uncinata (239), Crepis paludosa (3 53), C. parviflora, Crupina vul-
garis, Cucurbita Pepo, Cynoglossum Morisoni, C. officinale, Dahlia
(324), Dysodia chrysanthemoides (363), D. papposa (386), Echino-
spermum Lappula ( 347), £. Redowskii ( 199), E Virginicum, Echium
(344), E. Italicum (389) E. vulgare (22) (263) (271) (272) (345)
(377 ) (390) (391), E/isia Nyctelea, Epilobium tetragonum (345),

rigeron armerifolius (6), E. corymbosus (6), E. divaricatus (6), £.
elatus, E. glabellus (6), E. macranthus, E. strigosus (6), Eriogonum
nudum, Eupatorium cannabinum, E. perfoliatum, E. purpureum,
Gaillardia aristata (6), Galium Aparine, G. boreale, G. triflorum,
Geum urbanum (353), Gnaphalium sylvaticum, Grindelia squarrosa,
Gutierrezia Euthamiae, Helenium autumnale, Helianthella Parryi
(363), Helianthus annuus, H. Californicus, var. Utahensis (6), H.

ERYSIPHE 199

doronicoides, H. giganteus, H. grosse-serratus (263), H. Maximili-
ani, H. orgyalis, H. petiolaris, H. rigidus, H. strumosus, H. tuber-
osus, and var. subcanescens, Helichrysum arenarium, Hieracium
. albiflorum, H. boreale (205*), H. Canadense (61), H. incisum (230),
H. lycopsifolium, H. murorum (3) (345), H. prenanthoides, H.
sabaudum (214) (263), H. vulgatum (319), Humulus Lupulus (60),
Hydrophyllum Canadense, H. capitatum, H. macr ophyllum (324),
H. occidentale (259), H. Virginicum, Hyoscyamus albus, H. niger,
Hypericum humifusum (18), Inula Britannica (319), Z. Helenium
(272) (363), Z. hirta, I. Oculus- Christi, I. salicina, Iva frutescens
(60), 7. xanthifolia (36 3), Kuhnia eupatorioides, Lactuca muralis
(345), Z. pulchella (6), L. Scariola, L. viminea (344), Laportea bul-
bifera, Lapsana communis (20), Lithospermum arvense, L. officinale
(22) (390), Lycodesmia juncea, Lycopsis arvensis (107) (214), Ly-
copus Europaeus, Madia glomerata, Mentha aquatica, M. arvensis,
Mertensia maritima, M. Sibirica, Mikania scandens (10) (12), Mimu-
lus luteus (363), Myosotis intermedia (56) (263), M. sparsiflora (345),
M. sylvatica (56), Napaea dioica, Nicotiana Tabacum, Onopordon
‘Acanthium (319), Onosma simplicissimum (347), Parietaria debilis
(6), P. officinalis (230), P. Pennsylvanica, Phacelia circinata, P. Men-
zıesü, Phlomis tuberosa, Phlox divaricata, P. Drummond (366), P.
paniculata, Pilea pumila (265), Plantago Bellardi, P. Coronopus,
P. Kamtschatica, P. Lagopus, P. lanceolata, P. major and var.
Asiatica, P. maritima, P. media, P. Psyllium (214), Potentilla sp.
(347), P. bifurca (350), P. viscosa (235), Prenanthes alba (60), P.
purpurea, Prunella vulgaris (107), Pulmonaria mollis, P. officinalis,
Rudbeckia hirta, R. occidentalis (363), Rumex Acetosella ( 319),
Salvia glutinosa (15) (73*) (271) (272), Saussurea salicifolia, Scor-
sonera hirsuta (66), S. Hispanica, S. humilis, Scutellaria lateriflora,
Senecio hydrophilus, S. sylvaticus, S. vulgaris, Sesbania (1 59),
Silphium terebinthinaceum, Solanum Carolinense, Solidago Cana-
densis, S. Missouriensis (6). (386), S. nana, S. occidentalis (6), S.
rigida '(6), S. serotina, Sonchus arvensis, S. asper, S. oleraceus,
Stachys palustris (199) (363), Stevia sp., Symphytum officinale, S.
tuberosum, Tanacetum vulgare, Taraxacum officinale (3) (132)
(163) (176) (177) (271) (272) (290), Tecoma radicans (265),
Teucrium Canadense (366), T. Chamaedrys (237), Tragopogon
porrifolius, T. pratensis, Trigonella (206), Valeriana officinalis,

200 A MONOGRAPH OF THE ERYSIPHACEAE

Verbascum nigrum, V. phlomoides (20) (230) (272), V. pulveru-
lentum (319), V. thapsiforme (263), V. Thapsus (230), Verbena
angustifolia, V. Aubletia, V. bracteata (61), V. hastata, V. laevis,
V. officinalis (60), V. stricta, V. urticifolia, Verbesina encelioides
(363), V. occidentalis (9), Vernonia Baldwini, V. fasciculata, V.
Noveboracensis, Xanthium Canadense, X. Strumarium.

Distribution.—Evrore : Britain, France, Belgium, Netherlands,
Switzerland, Italy, Germany, Austria-Hungary, Servia (318),
Greece, Denmark, Norway, Sweden, Lapland (192), Finland (192),
Russia.

AFRICA : Algeria, Egypt.

Asta: Persia (389), Turkestan, Siberia (Minussinsk), Japan.

NEW ZEALAND.

NORTH AMERICA: United States—Maine, New Hampshire,
Vermont, Massachusetts, New York, Pennsylvania, Maryland,
New Jersey, Virginia, North and South Carolina, Ohio, Michigan,
Indiana, Alabama, Illirois, Mississippi, Wisconsin, Missouri, Iowa,
Minnesota, South Dakota, Kansas, Montana, Idaho, Wyoming,
Colorado, Utah, California, Washington. Canada—Newfound-
land, New Brunswick, Ontario.

E. cichoracearum, although very variable, is not as a rule a
difficult species to recognize under the microscope. In rare cases,
it closely approaches certain forms of E polygoni, with which it
has been much confused ; Æ. cichoracearum and E. polygoni, how-
ever, must certainly be considered as distinct species. In by far
the greatest number of cases, the present species may be at once
distinguished by the numerous, regularly 2-spored asci. The com-
paratively few forms of Æ. polygoni which have numerous asci are
always 4-8-spored. Although Æ. cichoracearum shows rarely one
or two asci in a perithecium with 3 spores, and although in £.
polygomi, as a rare exception, an ascus may contain only 2 spores,
yet as the result of an examination of many hundred specimens of
both species, it appears to me safe to consider the 2-spored ascus
as the central specific character of Æ, cichoracearum, and the 3-8-
spored ascus as that of £. polygoni. Usually unfailing characters
are also found in the large wider asci and larger, distinctly wider
spores of the present species. Often, moreover, £. cichoracearum
has a habit, difficult to define, by which it is known from Æ. poły-

ERYSIPHE 201

goni, as, e. g., on the leaves of Plantago, where the gregarious
perithecia more or less completely surrounded by the densely in-
terwoven, deep brown appendages give a characteristic appearance.
On the other hand, however, especially in cases where the peri-
thecia are small and scattered, forms of Æ. cichoracearum occur
which cannot be separated by the lens alone, or even by microscopic
examination of any external characters, but in these cases a safe
distinction will be found in the regularly 2-spored asci with larger
and wider spores. Asa rule, too, E cichoracearum is not found
with the few distinct appendages characteristic of many forms of
E. polygoni ; on Hydrophyllum Virginicum, however, a form occurs
with small perithecia (sometimes only 88 o in diameter), few asci
(often only 6), and appendages few and more distinct than usual ;
the asci, however, are regularly 2-spored.

It must be noted here that Z. cichoracearum has been frequently
stated to possess asci with 3-4 spores. Léveillé described and
figured Æ. horridula (the name given to the form of E. cichora-
cearum on Symphytum and Lycopsis) with 3-4 spores. In Le-
veillé's own specimens, however, in Berkeley’s herbarium at Kew,
from the same locality (Magny en Vexin) as that mentioned in
Ann. Sci. Nat., the asci are regularly 2-spored. In other spec-
imens on Symphytum 1 have occasionally found 3 spores, but only
by way of exception. Léveillé also described Æ. /amprocarpa
(the form of Z. cichoracearum on Flantago, etc.) as 4—8-spored, but
this was evidently only by a slip, as E /amprocarpa is figured
as 2-spored, and is placed in the key in the bisporous section of
the genus. Æ. spadicea Berk. & Curt. has been correctly referred
to E. cichoracearum ; the type specimen at Kew shows regularly
bisporous asci, although the species was described as having 8
spores.

E. cichoracearum has been confused not only with E polygoni,
but also with Æ. taurica and Sphaerotheca Castagnei. To E
taurica the present species is certainly closely allied, but may be
distinguished by the smaller size of the perithecia, asci and
spores ` Sphaerotheca is widely separated by the single ascus.

It has often been stated that Æ. cichoracearum occurs on Ta-
raxacum officinale, and in many exsiccati specimens supposed to
be this species on this host have been published. All these, how-

202 A MONOGRAPH OF THE ERYSIPHACEAE

ever, have proved on examination to be Sphaerotheca humuli, var.
fuliginea, and there seems reason to doubt if Æ. cichoracearum has
really ever occurred on Taraxacum.

In the case of the species which occurs commonly (in the coni-
dial condition) on the leaves of Cucumis and Cucurbita in cultiva-
tion, the determination has apparently been equally unsatisfactory.
Nearly all mycologists (e. g., Léveillé, Fuckel, Jaczwski, Passerini,
etc.) refer the fungus to Sphaerotheca Castagnei ; Schroeter,
however, places it under Æ. polygoni, and records the finding of spec-
imens with perithecia on Cucurbita Pepo. The perithecial stage of
this fungus on Cucurbita and Cucumis is evidently rare, and in all the
herbarium specimens and those in exsiccati (all named Sphacro-
theca Castagnei) examined I have found only the conidial stage. I
have, however, collected specimens on Cucurbita Pepo, at Reigate,
Surrey, England, in 1898, with a few perithecia, and the fungus here
was undoubtedly Æ. eichoracearum, the asci being regularly 2-
spored. It is interesting to note that a few American authors have
similarly determined the fungus ; e. g., Humphrey (169) records Æ.
cichoracearum on cucumber (Cucumis). It is, of course, possible
that more that one species of Erysiphe occurs on these host-plants,
but in the present case it seems more probable that the fungus has
been constantly named Sphaerotheca Castagnei merely because
this species was originally recorded on these host-plants, and it
would be very interesting to know if any example with perithecia
of Sphaerotheca really exists.

The Erysiphe on Valeriana officinalis has been referred without
exception (by Fuckel, Magnus, Karsten, Schroeter, etc.) to E
polygoni, but all the specimens I have seen so named, have proved
on examination to be Æ. cichoracearum. On the other hand, the
Erysiphe which occurs on thistles has been referred entirely to
E. cichoracearum, while, as a matter of fact, on the stems of
Cnicus lanceolatus, etc., an interesting form of E polygoni oc-
curs not uncommonly. Similarly, the Erysiphe on Anchusa and
Echium has been referred to E. cichoracearum, but all the speci-
mens I have seen so named in exsiccati, etc., prove to be E poly-
goni. The fungus on Cnicus eriophorus (in Montagne's herbarium)
referred to E taurica by Léveillé (2 14) is E. cichoracearum. The
Erysiphe on species of Galium, which has hitherto been referred to

ERYSIPHE 203

E. polygoni also belongs to the present species, and together with
the forms on Mentha, Lycopus and Scutellaria are peculiar in usu-
ally showing on the living host-plant no trace of spores in the
asci. These forms, as well as their connection with Æ. galeopsidis,
are discussed further.

A rather marked form of E. cichoracearum occurs on Senecio
vulgaris (Margery, Reigate, England, Oct., 1898). Here the my-
celium is persistent and covers the stems with a continuous white
covering, in which the perithecia are more or less immersed, giv-
ing an appearance very similar to that of the forms of E polygoni
on Liriodendron, Diervilla, etc. We not unfrequently find, how-
ever, E. cichoracearum on other host-plants with a thin effused
persistent mycelium on the leaves, as in some American examples
on species of Helianthus and on Ambrosia trifida—sometimes, as
in some specimens on Hydrophyllum Virginicum the mycelium has
a decidedly pink color.

An American form on Bigelovia viscidifiora (D. Douglast )
(Willis, Montana, Oct., 1888, leg. F. W. Anderson, in Herb
Missouri Bot. Gard.) is remarkable for the often large size of the
perithecia, which measure from 100-175 ^£, and for the numerous
asci, which are sometimes as many as 36. In these characters the
fungus approaches both Æ. polygoni var. sepulta and Æ. taurica ;
from the former it differs in the regularly bisporous asci, from the
latter in the slightly smaller perithecia, apparently not becoming
conspicuously concave or pezizoid, slightly smaller asci and
smaller spores. Although this form has been generally referred
to Æ. cichoracearum by American botanists, it must be considered
a marked form of this species in the larger perithecia and more
numerous asci (I have not seen elsewhere in Æ. cichoracearum
perithecia larger than 140 » in diameter), and certainly makes the
nearest approach of any American Zrysiphe to the Old World
species Æ. taurica. I have seen only the one specimen quoted
above, and this, unfortunately, for the most part scarcely mature.

In Grevillea, 15: 98. 1887 the following description of an
Erysiphe was given: “ E. vitigera Cke. et Mass. Hypophylla,
. mycelio floccoso, persistente, peritheciis gregariis, minutissimis
4 mm. diame.) sphaeroideis; appendicibus obsoletis vel cum
mycelio intertextis, ascis poriformibus (4 in singulo perithecio)

204 A MONOGRAPH OF THE ERYSIPHACEAE

50 x 30 p, bisporis. Sporidiis ellipticis, hyalinis, 18 x 9 u. On
leaves of grape vine. Near Melbourne (Mueller). Allied to E
lamprocarpa, but apparently distinct from all the disporous species.
We have seen the floccose mycelium before, but without peri-
thecia. Hitherto we have not been successful in detecting or iden-
tifying the conidia. Destructive to the vines in Australia, but
there is no evidence on which to connect it with Oidium Tuckeri,
but on the contrary, the floccose mycelium is much more woolly,
and commonly sterile, at least in so far as we have seen specimens.
Leaves and twigs sent to us from Australia last year with a thick
cottony-white mycelium, but without fruit of any kind, was prob-
ably the same species. It has every apy ce of being a danger-
ous pest." On the sheet with the type-specimens at Kew, there
is a drawing (reproduced in Cooke's Handbook of Australian Fungi)
(89) or of an ascus with two spores, but on the type-specimens
themselves I can find no fungus. The host-plant is one of the
forms of Vitis vinifera in which the under surface of the leaves,
the young wood, etc., are covered with a more or less dense cob-
webby tomentum, and it appears that this has been mistaken for
floccose mycelium, as of this there is no trace. The description
given above of the mycelium—« commonly sterile," etc.—favors
this view. It is possible that the perithecia which were seen were
stray ones of E. cichoracearum.

The fungus described by de Thuemen (354) as Oidium tabaci,
on Nicotiana Tabacum, from Portugal is apparently the conidial
form of Æ. cichoracearum, as on specimens sent to me by Professor
Gennardius, from Argos, Greece (named Q. tabaci), there occur
numerous perithecia of this Erysiphe (see Passinini 2 72):

3. E. carEopsipis DC. [Figs. 127-129]

Mucor Erysiphe L. Sp. Pl. 2: 1186 (partim). 1753.

Erysiphe galeopsidis DC. Fl. Fr. 6: 108. 1815; de Bary,
Beitr. Morph. Phys. Pilz. r°: &xiii. 49... 1870: Sace. Syll.
Fung. 1: 16. 1882; Wint.; Rabenh. Krypt. Fl. Deutschl, 1?: 33.
1884; Karst. Act. Soc. Faun. Fl. Fenn. 2: 93. 1885; Burr. &
Earle, Bull. Ill. State Lab. Nat. Hist. 2: 404. 1887; Burr. ; Ell.
& Everh. N. Amer. Pyren. 13. 1892; Jacz. Bull. l'Herb. Boiss.
4: 731. 1896; Oudem. Rev. Champ. Pays.-Bas. 2: 95. 1897.

ERYSIPHE 205

Alphitomorpha communis, var. labiatarum Wallr. Berl. Ges. Nat.
Freund. Verh. 2: 31. 1819.

A, lamprocarpa Wallr. Berl. Ges. Nat. Freund. Verh. 1 : 33.
1819.

A. ballotae Wallr. Ann. Wett. Ges. 4: 239. 1819.

A. labiatarum Wallr. Ann. Wett. Ges. 4: 241. 1819.

Erysibe lamprocarpa, var. galeopsidis Ficin. & Schub. Fl. Ge-
gend. Dresd. 2: 305. 1823.

E. lamprocarpa Schlecht. Fl. Berol 2: 169. 1824; Lk:
Willd. Sp. Pl. 6: 108 (excl. var. plantaginis). 1824.

E. communis, var. labiatarum Lk. ; Willd. Sp. Pl.6 : 106. 1824.

Erysiphe labiatarinm Chev. Fl. Par. 1: 380. 1826.

E. communis Fr. Syst. Myc. 3: 239 (partim). 1829.

E. lamprocarpa ; var. galeopsidis Duby, Bot. Gall. 2: 869.
1830.

Alphitomorpha lamprocarpa ; var. labiatarum Wallr. Fl. Crypt.
Germ 23 :797.:1853

Erysiphe quisquiliarum Schwein. Syn. F ung. Am. Bor. 270.
1834; Sace Syll. Fung. 1 : 23. 1882.

E. chelones Schwein. Syn. Fung. Am. Bor. 270. 1834 ; Sacc.
Syll. Fung. 1: 21. 1882.

E. lamprocarpa Kickx. Fl. Crypt. Env. Louv. 140. 1835;
Lev. Ann. sci. nat. III. 15 : 163 (partim). 1851; Karst. Myc.
Fenn. 2: 192 (partim). 1873.

Erysibe lamprocarpa Rabenh. Fl. Lusat. 2 : 420. 1840.

SE lamprocarpa, var. labiatarum: Rabenh. Deutschl. Krypt. Fl.

en em

E rn DC. ; Schroet. ; Cohn’s Krypt. Fl. Schles. 3:
239.. 18

Exsicc.: Fckl Fung. Rhen. 654, 656; Karst. Fung. Fenn.
Exsicc. 172; Sacc. Myc. Ven. 612, *613, 902; Lib. PL Crypt.
Ard. fasc. 2, 183; Cooke, Fung. Brit. Exsicc. ed. 2, 200 (spec. on
Stachys only), 596 ; Desmaz. Pl. Cr. Fr. ed. 1, ser. 1, 516; ser.
- 2, *110; de Thim. Myc. Univ. 1252; Syd. Myc. March. 336;
Westend. Herb, Crypt. Belg. 409; Rab. Fung. Eur. 1738, 1740,
1741; de Thüm. Fung. austr. 753, *1043, 1142 ; Roumeg Fung.
Gall. Exsicc. 2451; Rab. Herb. Myc. ed. 2, 485 ; Sacc. Myc.
Ven. 613; & 1491 sub Sphaerotheca Castagnei ; *Kneiff. & Hartm.
Pl. Crypt. Bad. 160; *Erikss. Fung. Par. Scand. 37b.

206 A MoNOGRAPH OF THE ERYSIPHACEAE

Hosts —Ballota nigra, Chelone glabra, Chelonopsis moschata,
Eupatorium ageratoides [?], Galeopsis Tetrahit, G. versicolor, La-
mium album, L. amplexicaule (176) (230), L. Galeobdolon, L. ma-
culatum, L. intermedium, L. purpureum, Leonurus Cardiaca, Mar-
rubium vulgare, Phlomis Herba-venti (172), Salvia sp. (176), S.
verticillata (3) (290), Scutellaria lateriflora (61), S. parvula (61),
(363), Stachys alpina, S. aspera and vars. glabra (324) and Japonica,
S. ciliata and var. pubens, S. cordata (324), S. Germanica, S. melis-
saefolia, S. palustris, S. sylvatica, Teucrium Canadense, Verbena
urticifolia (10).

Distribution. —EUROPE: Britain, France, Spanish Peninsula
(110), Belgium, Netherlands, Switzerland (176), Italy, Austria-
Hungary, Denmark, Norway, Sweden, Russia.

Asta: Turkestan (Seravschan) (206), Siberia (Minussinsk)
(311) (347), Japan.

NORTH AMERICA : United States—Massachusetts, New York,
Delaware, Michigan, Indiana, Illinois, Wisconsin, Minnesota,
South Dakota, Kansas, Montana, Wyoming, Washington ; Can-
ada—Newfoundland, Ontario.

De Bary (99, p. 49), in 1870, revived the name E galeopsidis
DC. for the Erysiphe on Galeopsis Tetrahit, Stachys sylvatica and
Lamium purpureum, distinguishing it from E lamprocarpa (E.
cichoracearum) described as having “haustoria exappendiculata
v. appendiculata, non lobulata," by the presence of ‘haustoria
' lobulata”” De Bary made the following observations on E
Saleopsidis : “ Diese Form unterscheidet sich von der vorigen (LE.
lamprocarpa) durch die gelappten Haustorien-Anhängsel, sie ist
sonst der auf Plantago und Borragineen wachsenden /amprocarpa
sehr ähnlich. Eine Haupteigenthümlichkeit, wegen deren ich sie,
zur Zeit weingstens, von allen anderen Formen trennen muss, ist
die, dass sie nicht wie letztere noch auf dem lebenden Pflanzen-
theil Sporen in ihren Ascis bildet, sondern hier immer ohne
Sporen vorkommt,"

All subsequent authors have followed De Bary in maintaining .
E. galeopsidis as a distinct species, and have relied on the lobed
haustoria and absence of spores in the ascus as separative char-
acters from £. cichoracearum. Most authors state that the spores
(two in a) are produced in the following year, and that the

-

ERYSIPHE 207

species is confined to certain host plants belonging to the Labiatae.
In the size, etc., of the perithecia, nature of appendages, number
and size of asci, etc., there is no difference—as indeed is generally
admitted—between Z. galeopsidis and E. cichoracearum, so that the
claim of the former to rank as a distinct species rests on two sup-
posed separative characters, viz.: the lobed haustoria and the non-
development of spores on the living host-plant.

This latter peculiarity is found also as a rule in E gramints,
but we must notice that in this species spores are sometimes pro-
duced in late summer or autumn,’so that in E graminis, at least,
it is seen that this character is not one of specific importance.

So long, however, as the absence of spores and the presence
of lobed haustoria could be considered as correlated characters,
and ones not occurring in E cichoracearum, E. galeopsidis could
be maintained as a distinct species. Some cases I have examined,
however, make me doubt if we can consider either of these char-
acters as absolutely characteristic of E. galeopsidis. In the exam-
ination of a large amount of material I have certainly found that
the Zrysiphe on species of Lamium, Galeopsis, Stachys, etc., in-
variably contain asci without any trace of spores, and in all cases
where examination was made the mycelium was found to possess
lobed haustoria. But, on the other hand, as regards this character
of the non-production of spores, there are forms of E cichorace-
arum which appear to be connecting links. Such are the forms
on Mentha arvensis, M. aquatica, Lycopus Europaeus and Scutellaria
lateriflora. On these host-plants, some specimens of the fungus,
apparently mature, have perithecia in which the asci show no trace
of spores, and are in fact indistinguishable, as regards perithecia,
from E. galeopsidis ; in other specimens two more or less well-
formed spores are found in the ascus. The haustoria of the fun-
gus on these hosts are not lobed (although there is sometimes a
tendency for them to have a crenulate margin), and for this
reason, probably, De Bary placed the fungus on Mentha and Ly-
copus under £. cichoracearum. The fungus on Scutellaria very
rarely shows any signs of the formation of spores in the ascus,
` and it is probably on this account that Burrill places it under E
&ateopsidis ; the haustoria, however, are not definitely lobed. An-
other striking case is that afforded by the fungus on species of

208 A MoNOGRAPH OF THE ERYSIPHACEAE

Galium. Curiously enough, this form in Europe has been referred
by all botanists to E communis (E. polygoni ), although it undoubt -
edly belongs to Æ. circhoracearum, of which it appears to be a
form approaching Æ. galeopsidis. In all the European specimens
I have examined the perithecia have contained asci without any
trace of spores, and the habit, size, shape and number of asci,
etc., further show that the fungus does not belong to E polygoni.
Moreover, in Turkestan specimens on Galium boreale and other
species of the genus, and in American ones on Galium aparine
and G. triflorum the asci are régularly bisporous with apparently
ripe spores. For this reason American mycologists have placed
the form under Æ. cichoracearum. The shape of the haustoria in
the form on Galium appears also variable. These, although
small, and in this: respect very unlike those of E galeopsidis, are
sometimes, although rarely, distinctly lobed ; in other specimens
they resemble those of Æ. cichoracearum. It appears, therefore,
from the above cases, that Æ. cichoracearum is sometimes similar
to £. galeopsidis in not producing spores on the living host-plant.

The difference in the size and shape of the haustoria in Æ.
cichoracearum and E galeopsidis is, as a rule, striking. The
haustoria of the former species (examples on about thirty different
host-plants were examined) are small and simple, those of the lat-
ter are much larger, much lobed irregularly, or often more or less
reniform (deeply bi-lobed) in shape. Among some American ex-
amples, however, I was surprised to find in two specimens named
E. cichoracearum on Eupatorium. ageratoides (one from Madison,
Wisconsin, Sept., 1882, L. H. Pammel) in Professor Earle’s
- herbarium ; the other from Oregon, Illinois, Sept. 12, 1888 (in the
Herbarium of the University of Illinois), haustoria of exactly the
same size and shape as those on examples of E. galeopsidis on Gale-
opsis. Unfortunately, both these specimens are apparently rather
young, and the asci contain no spores, It is, therefore, impossible
to say whether we have in this case a form of Æ. cichoracearum
with lobed haustoria, or whether it may not possibly be that of £.
galeopsidis, hitherto supposed to be confined to Labiatae and Chelone
among Scrophularineae, sometimes occurs on Compositae. In an-
other case the fungus is undoubtedly Æ. cichoracearum. This is the
specimen on Sonchus arvensis in Syd. Myc. March. 3051, and in

ERYSIPHE 209

this example among simple haustoria some occur which are dis-
tinctly lobed (Fig. 131). These latter are not quite so large and
certainly not so much lobed as in typical E. galeopsidis, but their
occurrence tends to break down the distinction between the two
forms.

Whilst, therefore, admitting that the form known as £ gale-
opsidis on Galeopsis, Lamium, Stachys, etc., is well characterized
by the large, lobed haustoria and absence of spores on the living
host plant, it seems that forms of Æ. cichoracearum exist in which
the latter (and to some extent the former) character is found.
Whether these intermediates are numerous enough to compel us
to unite E. galeopsidis with £. cichoracearum, or whether the former
should rank as a species, or more probably as only a variety, can
only be proved by further observations, especially with regard to
the haustoria of specimens of E, cichoraccarum on its numerous
host-plants. For this purpose young examples are in many cases
necessary, as the mycelium is commonly evanescent in the mature
condition of the fungus.

4. E. craminis DC. [Figs. 156, 159, 160]

Erysiphe graminis DC. Fl. Fr. 6: 106. 181 5; Lév. Ann.
sci. nat. III. 15: 165. pl. ro. f. 33. 1851; Tul. Sel. Fung.
Carp. 1: 212. 1861; Cooke, Micr. Eung.:220. M. ir. J. 335,
236. 1865; Cooke, Handb. Brit. Fung.2: 651. 1871; Karst.
Myc. Fenn. 2: 193. 1873; Sacc. Syll Fung. z: 19. 1882;
Wint. in Rabenh. Krypt. Fl. Deutschl 1: 30. 1884; Karst.
Act. Soc. Faun. Fl. Fenn. 2: 93. 1885; Burr. in Ell. & Everh.
N. Amer. Pyren. 15. 1892; Jacz. Bull. l'Herb. Boiss. 4: 728.
1896 ; Oudem. Rév. Champ. Pays-Bas. 2: 98. 1897.

` Alphitomorpha communis, var. graminearum Wallr. Berl. Ges.
Nat. Freund. Verh. 1: 31. 1819; Wallr. Fl. Crypt. Germ. 2:
758... 1811.

Erysibe communis, var. graminum Lk. in Willd. Sp. Pl. 6: 106.
1824. :

Erysiphe communis Fr. Syst. Myc. 3: 239 (partim). 1829.

E. communis, var. graminum Duby, Bot. Gall. 2: 869. 1830;
Rabenh. Deutschl. Krypt. Fl. 1: 232. 1844.

E. communis, var. graminis Dur. & Mont. Fl. d’Alger. (Crypt.)
565. 1846-9.

210 MONOGRAPH. OF THE ERYSIPHACEAE

Erysibe communis Rabenh. Fl. Lusat. 2: 419. (partim).
1840.

E. graminis DC. Schroet.; Cohn, Krypt. Fl. Schles. 3: 240.
1893.

Exsicc.: Bri. & Cav. Fung. Par. 174; Lib. Pl. Crypt. Ard.
fasc. 2, 182; Roumeg. Fung. Gall. Exsicc. 766, 1163 ; Syd. Myc.
March. 1139, 1350, *3461, *4123; Desmaz. Pl. Cr. Fr. ed. 1
ser. I, 1109 (B only), *ed. 2, ser. t, 509 B; Rab. Fung. Eur.
671; Karst. Fung. Fenn. Exsicc. 677; Rab. Herb. Myc. ed. 2,
473, 759; de Thüm. Fung. Austr. 1244; de Thüm. Myc. univ.
257; Fckl. Fung. Rhen. 659; Westend. Herb. Crypt. Belg. 554;
Vize, Fung. Brit. 143; Klotzsch, Herb. Myc. 62; Jack, Lein. &
Stizenb. Krypt. Bad. 829 ; Ayres, Brit. Fung. 23; Ell. & Everh.
N. Amer. Fungi, 2813; Erb. Critt. Ital. ser. 1, 286 (in Herb.
Mus. Florence); *Ell. & Everh. Fung. Columb. 505; *Erikss.
Fung. par. scand. exsicc. 238; *Seym. & Earle, Econ. Fung. 96.

Usually epiphyllous, but sometimes amphigenous ; mycelium
more or less persistent, effused or forming scattered patches, at
first white, frequently becoming pale brown or gray; perithecia
large, 135-280 # in diameter, usually'about 200 p, scattered or
gregarious, globose-depressed, becoming concave, usually more
or less immersed in the lanuginose persistent mycelium, which is
formed of sparingly branched, curved, rather rigid thick-walled or
solid, shining, interlaced hyphae, 4-5 p wide, cells of perithecium `
obscure ; appendages rudimentary, few or numerous, very short,
simple or sparingly branched, pale brown; asci numerous, 9-30,
usually from 15-20, varying from cylindrical to ovate-oblong,
more or less longly pedicellate, 70-108 x 25-40 p; spores 8 (or
d 4), 20-23x 10-13 jr, seldom produced on the living host-

ant.

Hosts.—Agropyron caninum (319), A. glaucum, A. repens,
A. scabrum, A. tenerum (151), Agrostis alba (263), A. éxarata
(60), Alopecurus agrestis (56), Apera Spica-Venti, Arrhenatherum
avenaceum (370), Avena fatua (66), A. sativa, Beckmannia erucac-
formis, Bromus asper (319), B. breviaristatus, B. madritensis (16),
B. mollis (3) (132) (224) (229) (319) ( 399), B. rubens, B. secalinus
(319), B. sterilis, B. tectorum ( 399), B. unioloides (60) (151), Dac-
tylis glomerata, Deschampsia caespitosa (319), Elymus condensatus
(363), Festuca arundinacea (176), F. elatior, F. gigantea (y *

heterophylla (319), Glyceria aquatica (6), G. nervata (6), Holcus .

ERYSIPHE 211

mollis (319), Hordeum jubatum (6), H murinum (272), H. seca-
linum, H. vulgare, Lolium perenne (107), Milium effusum (319),
Panicum sanguinale (60), Phleum pratense (345), Poa annua, P.
Buck eyana, P. bulbosa, P. nemoralis, P. pratensis, P. serotina, P.
sinaica (233), P. tenuifolia, P. trivialis, Saccharum officinarum
(143), Secale cereale (22) (69) (399), Sesleria caerulea (107), Zri-
ticum sativum, T. Spelta, T. vulgare.

Distribution —EvROPE: Britain, France, Spanish Peninsula
(101), Belgium, Switzerland (176), Italy, Germany, Austria-Hun-
gary, Denmark, Norway, Sweden, Finland, Russia.

AFRICA : Algeria.

Asta: Cyprus, Transcaucasia (338), Persia (233), Turkestan
(Seravschan) (206), Siberia (235) (348), Japan.

AUSTRALIA : Thistle Island, Victoria and New South Wales
(225).

NORTH AMERICA : United States— Massachusetts, New York,
Pennsylvania, West Virginia (249), South Carolina (3 5), Michigan,
Illinois, Mississippi (361), Iowa (165), South Dakota, Kansas,
Montana, Idaho, Wyoming, Colorado, Nevada (363), California,
Washington ; Canada—Newfoundland, Ontario.

A very distinct species in the large size of the perithecium, and
the large, usually numerous, asci. In these characters it some-
what recalls Æ. /aurica, which differs, however, in the constantly -
bisporous asci. In E graminis the asch usually show no trace of
spores, being filled merely with granular protoplasm. When the
spores are produced they are eight in number; according to
Wolff, however, sometimes the number is only four. In Europe,
E. graminis, as a general rule, is characterized by this absence of
ascospores on the living host plant, and in the numerous material
examined only two cases have occurred in which any signs of
their production were observable. Among the twenty four ex-
amples of Æ. graminis in European exsiccati, mentioned above,
only one (Rab. Fung. Eur. no. 671) showed spores in the ascus.
This specimen was gathered on Triticum sativum in August ; two
of the asci, each containing 8 spores, are represented at Fig. 159.
The other specimen (in the Herbarium of the Florence Museum)
is on Bromus sterilis, and was collected in October. Here eight
very young spores were seen in some of the asci. In the United

212 A MONOGRAPH OF THE ERYSIPHACEAE

States, however, the development of ascospores in autumn, or
even late summer, appears to be not uncommon. Anderson (6)
mentions that ripe ascospores have been found on a species of Poa
in Missouri in July, on Beckmannia erucacformis and Hordeum
Jubatum in October, and on Poa tenuifolia in November, or usu-
ally by the middle of October. Ina specimen on Poa nemoralis,
gathered by Griffiths & Carter in South Dakota in August, I have
found 8 well-formed spores in the ascus.

A very interesting account is given by Wolff (399) of the de-
velopment and germination of the ascopores. This author found
that if perithecia of E graminis containing asci in which no spores
are yet formed are placed in water (damp atmosphere, or even a
position on water was found to produce no result) they showed,
after two or three days, a change in the protoplasmic contents of
the asci, leading up gradually, in the course of five or six days, to
the formation of usually eight, or seldom only four, spores.
These ascospores, like the conidia, were found to germinate read-
ily in a damp atmosphere or in a drop of water. In dry air, how-
ever, at a temperature of 22°, they perished after 1 or 114 hours.
Under favorable conditions each ascospore was found to produce
several germinating tubes, which at most reached to twice the di-
ameter of the spore and which perished if after a period of 30
hours at the longest they failed to reach the epidermis of a suit-
able host-plant. If, however, this was reached the hyphae pene-
trated it and proceeded to form a mycelium in the same manner
as those of a germinating conidium, 2. e., by first forming a haus-
torium, and then spreading from this center. It may be noted that
Wolff tried to infect grasses with Z. communis (E. polygoni ), and
conversely the host plants of E. polygoni (Trifolium, Lupinus, etc.)
with Æ. graminis, but without success in either case.

The perithecia of E graminis, when carefully isolated from the
persistent mycelium are seen to possess only very short rudi-
mentary appendages ; a few surrounding hyphae of the persistent
mycelium often adhere to the perithecia when the latter are taken
out, and these hyphae have apparently been mistaken by many
authors for true appendages.

Garovaglio and Cattaneo (143) give an interesting account of
the manner in which Æ. graminis attacks wheat. These authors

ERYSIPHE 213

were unable to find any spores in the asci of perithecia occurring
on living host-plants, but by placing leaves bearing perithecia in
water, and leaving them in this position for some days under a
bell jar, they were able to induce the formation of spores (8 in
each ascus) Æ. graminis occasionally causes serious damage to
forage and cereal crops, especially to wheat. It is stated in the
Jour. Roy. Agric. Soc. England, for 1898 (184), that the fungus
“appears to be greatly encouraged in wheat that is growing lux-
uriantly from an abundance of nitrogenous manure. . . . Sprink-
ling with flowers of sulphur may be useful if applied in the early
stages of the attack." Outbreaks of the disease to a serious de-
gree have been reported on the continent, occurring especially on
winter-sown cereal crops; sulphur has been employed with suc-
cess (see 188, 189, 191 and 400). Anderson (4), speaking of the
attacks of Æ. graminis in Montana, U. S. A., says: “it affects
chiefly the Poas, and is especially damaging to P. tenuifolia, one
of our most valued forage grasses."

Oidium monilioides Desm. is the conidial stage of the present
species.

The record of “ E. graminis” on Circaea Lutetiana in Lamb.
Fl. Myc. Belg. 2, 188, is evidently an error for £. polygoni.

Burrill (60, p. 15) concludes his description of E graminis
with the following remark : ** Anderson says there are sometimes
as many as 20 sporidia in an ascus—a variation not reported else-
where." I cannot help thinking that “ 20 asci in a perithecium "'
was originally intended.

5. E. roRrILIS (Wallr.) Fr.

Alphitomorpha tortilis Wallr. Berl. Ges. Nat. Freund. Verh. 1 :
35. 1819; Wallr. Fl. Crypt. Germ. 2: 756. 1833.

A. corni Wallr. Ann. Wett. Ges. 4: 244. 1819.

Erysibe tortilis Lk. Willd. Sp. Pl. 6: 111. 1824; Rabenh.
Deutschl. Krypt. Fl. 1: 231. 1844 ; Schroet. in Cohn's Krypt. Fl.
Schles. 3: 241. 18034.

Erysiphe tortilis Fr. Syst. Myc. 3: 243. 1829; Berk. Sm.-
Eug. Pl. 5: 327. 1836; Levi Ann: wi we IE 15: et pl.
r J 35. 1858, Iul Sel Pune. Cu EI Wg. 7. 6.
1861; Cooke, Micr. Fung. 221. %. r2. ff. 245, 246. Geen de

214 A MONOGRAPH OF THE ERYSIPHACEAE

Bary, Beitr. Morph. Phys. Pilz. 1: $ XII. sr. 1870. Cooke,
Handb. Brit. Fung. 2: 651. - 1871; Sacc. Syll. Pung. £515
1882 ; Wint. Rabenh. Krypt. Fl. Deutschl. 17: 32. 1884; Jacz.
Bull. l'Herb. Boiss. 4: 729. 1896; Oudem. Rev. Champ. Pays.-
Bas. 2: 95. 1897.

E. corni Duby, Bot. Gall. 2: 870. 1830; Cast. Cat. Pl.
Mars. 191. 1845.

Exsıcc. : Rab. Fung. Eur. 672, 1521, 2033; Syd. Myc. March.
197, 1637; Desmaz. Pl. Cr. Fr. ser. 1, 266, * ed. 2, ser. 1, 815;
Cooke, Fung. Brit. Exsicc. 98, ed. sec. 286; Vize, Fung. Brit.
97; Rehm, Ascom. 548; Berk. Brit. Fung. 204; Oudem. Fung.
Neerl Exsicc. 161; Roumeg. Fung. Gall. Exsicc. 974; Fckl.
Fung. Rhen. 672; de Thüm. Fung. austr. I34; Sacc. Myc. Ven.
601; Rab. Herb. Myc. ed. 2, 472; de Thüm. Myc. univ. 258 ;
Kunze, Fung. Select. exsicc. 61, 577; Westend. Herb. Crypt.
Belg. 552; Vestergr. Microm. rar. select. 103; Erb, Crit, Hal
ser. 2, 986 (Herb. Mus. Florence); * Krieg. Fung. Saxon. 724;
* Wartm. & Schenk, Schweiz. Krypt. 42 5.

Hypophyllous, very rarely epiphyllous ; mycelium arachnoid,
effused, evanescent, or very slightly subpersistent in scattered

65-110 # in diameter, cells distinct, 10-20 # wide, usually over
15 #, appendages well developed, very long, 10-20 times the
diameter of the perithecium, 8—20 or more in number, 4—5 nm wide,
brown, paler above, septate, flexuose, assurgent and fasciculate
above, flaccid ; asci 2—5, usually 4, broadly ovate to subglobose,
with or without a stalk, so-60 x 36-45 ^; spores 4-8, usually 8,
20—24 X 10-14 p.

Hosts.—Cornus alba (3) (263), C. sanguinea.

Distribution —EvRoPE: Britain, France, Belgium, Netherlands,
Switzerland, Italy, Germany, Austria-Hungary, Denmark, Sweden,
Russia.

Distinct in the genus in the possession of the always long,
well-developed appendages, assurgent and fasciculate above after
the manner of some species of Microsphaera.

E. tortilis is frequently recorded (c. g., by Bessey (40, p. 13),
Trelease (366, p. 9), Rose (299)) from the United States on
Clematis Virginiana, but the numerous specimens I have seen so
named all belong to E polygoni, and it seems very probable that

ERYSIPHE 215

E. tortilis is confined to Europe. Burrill (60) records the present
species as occurring in the United States, remarking as follows:
“On Cornus sanguinea, Missouri (Tracy and Galloway). This is
here included solely upon the authority given, and apparently upon
one collection. In Europe the fungus is common on the same
host, and as this is abundant in cultivation with us, it is altogether
probable that this parasite may be frequently found."

It may be noticed that certain forms of Æ. polygoni (especially
those on Clematis) are very similar to E tortilis when examined
under the microscope with the appendages flattened horizontally
by the pressure of a cover-glass; when examined a situ on the
leaf, however, it is seen that in E ¢ortilis the appendages are as-
surgent, altogether free from the surface of the leaf, and fascicu-
lately wound together, while those of the form of Æ. polygoni in
question spread horizontally on the leaf.

E. tortilis is sometimes recorded on Cornus Mas, but all the
specimens so named that I have seen have proved to be Phyllac-
tinia corylea. The record by Bagnis (18) of the occurrence of the
present species on ellis annua requires confirmation.

It is possible that the earliest specific name for this species
is corni, given by Wallroth in the Ann. Wett. Ges., in 1819.
The name Zorte, given by the same author in the Verhandl.
Berl. Gesell. Nat. Freund., dates from the same year, and there
appears to be no evidence as to which work appeared first. Un-
der these circumstances, I have used the name ‘¢ortilis, as being
the one in general use, and as that retained by Wallroth himself
in his later work, Flora Crypt. Germaniae.

6. E. raurica Lév. [Figs. 145-150, 152-154]

Erysiphe compositarum Duby, Bot. Gall. 2: 870 (partim).
1830.

E. taurica Lév. Demidoft’s Voy. Russ. merid. (bot.) 119. A. 6.
f. 5. 1842; Dur. & Mont. Fl. d'Algér. (Crypt.) 566. 1846-9;
Lév. Ann. sci. nat. III. 15: 161. pl. ro. f. 30. 1851 ; Sace. Syll.
Fung. 1: 16. 1882.

Erysibe depressa Rabenh. Deutschl. Krypt. Fl. 1: 232 (par-
tim). 1844.

Erisyphe pieridis Cast. Cat. Pl. Mars. 192. 1845.

216 A MONOGRAPH OF THE ERYSIPHACEAE

E. lappae Cast. Cat. Pl. Mars. 192. 1845.

E. Duriaei Lev. Ann. sci. nat. III. 15: 165. pl. ro. f. 32.
1851; Sacc. Syll. Fung. 1: 17.- 1882.

E. lanuginosa Fckl. Bot. Zeit. 27. 1871; Sacc. Syll. Fung.
15-20. 1882.

E. Saxaouli Sorok. Rev. Myc. 146. pi. 89 (15). f. 237-236.
1889; Sace. Syll. Fung. 9: 370. 1891.

E. armata Sorok. Rev. Myc. 146. pl. 88 (13). f. 195—203.
1889; Sacc. Syll. Fung. 9: 370. 189r.

E. alhagi Sorok. Rev. Myc. 147. pl. 89 (15). f. 237-239.
1889; Sacc. Syll. Fung. 9: 371. 189r.

E. pegani Sorok. Rev. Myc. 148. pl 91 (16). f. 246-251.
1889; Sacc. Syll. Fung. 9: 371. 1891.

E. lichenoides Trab. & Sacc.; Sacc. Syll. Fung. 11: 253.
1895.

E. papilionacearum Kom. Scripta Bot. Hort. Univ. Imp.
Petropol. 4: 271. 1895.

E. lanata P. Magn. Verh. k. k. zoöl.-bot. Gesell. Wien, 49:
100. pl. 3. f. 20-22. 1899.

Microsphaera Bornmuelleriana P. Magn. Verh. k. k. zodl.-bot.
Gesell. Wien, 49: 100. p/. 3. f. 23-255 18.90.

Exsıcc. : Roumeg. Fung. Select. Exsicc. 601 7; Rab. Fung.
Eur. 1520; and 1735 sub E communis; Sacc. Myc. Ven. 1169
sub Æ. /amprocarpa ; Syd. Myc. March. 1076 ; and 1351 sub E
cichoracearum ; de Thüm. Myc. Univ. 21 53 sub Æ. /amprocarpa ;
Erb. Critt. Ital. ser. 2, 145 sub E communis ; and 445 sub £.
Montagnei (in Herb. Mus. F lorence). j

Amphigenous, often covering the whole plant; mycelium
usually persistent, effused, densely compacted, tomentose-mem-
branaceous, or crustaceous, usually white, rarely pale buff in

_

| the p
sistent mycelium, large, 135—240 ^ in diameter, usually about
200 #, soon becoming concave, cells obscure ; appendages usually
very numerous, densely interwoven, rather short, more or less
vaguely branched, colorless or brown, sometimes very short or
even obsolete ; asci 7-38, usually about 20, large, from narrowly
cylindrical to ovate, usually longly pedicellate, 75-110 (usually
about 90) x28—40 p; spores 2, large, variable in size, usually
about 32 x 18 p, but varying from 28—40 x 14-22 p, Sometimes
slightly curved.

ERYSIPHE 217

Hosts.—Acanthophyllum glandulosum, Alhagi camelorum (206),
A. maurorum, Althaea ficifolia, A. kurdica, Arctium minus, Arte-
misia Dracunculus, Astragalus sp., Capparis spinosa, Carduus
crispus (132), Carlina corymbosa, C. lanata, Carthamus lanatus,
Carinthe major (214), Chondrilla juncea, Cicer songaricum (206),
Clematis songarica, Cnicus arvensis (214), C. cardunculus, C. lan-
ceolatus (55) (132), Coccinea dubia (206), Cynara cardunculus,
Daucus maximus, Diarthron vesiculosum (206), Dorycinum herba-
ceum (214), Elaeoselinum Lagascae, Eryngium campestre, E Noë-
anum (233), Euphorbia lanata, Exochorda Alberti (19), Foenicu-
lum vulgare, Gundelia Tournefortii, Haloxylon ammodendron, Hap-
lophyllum Sieversianum (206), Hedysarum Falconeri, Helianthemum
oelandicum, Inula nervosa, Nepeta podostachys, Odontospermum
aquaticum, Peganum Hamala, Phlomis Herba-venti, P. tuberosa
(214), Picris hieracioides, Psoralea drupacea, Salsola canescens
(233), Saussurea (214), Scutellaria multicaulis, Taraxacum mon-
tanum, Teucrium chamaedrys, Thevenotia scabra (233), Thymelaea
sp. Verbascum Blattaria, V. phlomoides, V. speciosum, Vicia tenu-
Yolia, Zygophyllum Fabago.

Distribution. —EUROPE: France, Spain, Italy, Greece, Ger-
many, Austria-Hungary, Russia.

AFRICA : Algeria.

Asta: Turkey, Syria, Persia, Turkestan, India.

E. taurica has been much confused with both Æ. cichoracearum
and Æ. polygoni. From the latter species the very numerous regu-
larly bisporous asci at once distinguish it. From the former it is
known by the large size of the asci and spores, and from both by
the very large concave or “ pezizoid ” perithecia. The latter fea-
ture, indeed, is so characteristic that it makes Æ. taurica one of the
few species of the Erysiphaceae which can be safely determined
with the lens. ;

I am quite convinced that E Duriaei Lév., E. lanuginosa
Fckl., Æ. lichenoides Trab., and E. papilionacearum Kom., all be-
long to the present species. Æ. Duriaei (on species of Phlomis) and
E. papilionacearum (on Astragalus, Psoralea and Cicer) have been
stated to differ from Æ. taurica in having colored appendages ; the
former, also, in possessing only 8 asci. These characters do not
hold good. There is a specimen of E Duriaei in the Kew Her-

E

218 A MONOGRAPH OF THE ERYSIPHACEAE

barium from Léveillé’s herbarium, labelled ** Gallia austral. ad fol.
Phlomidis herba-venti," which is apparently the specimen referred
to by Léveillé in his monograph. In this specimen the perithe-
cium contains up to 30 asci. In authentic specimens of Æ. papi-
lionacearum, as well as in the example of E Duriaei mentioned
above, the appendages are sometimes colorless, sometimes pale
brown, and we find just the same variation in these characters in
authentic specimens of Æ. taurica on other hosts. Both plants
must be undoubtedly referred to E. ¢aurica, and it may be noticed
that Komarow (206, p. 39) although giving £. papilionacearum
specific rank, speaks of the plant as forming a passage from /aurica
to Duriaei. E. lanuginosa, on Daucus maximus from Greece, was
originally described by Fuckel as ** 8-12-spored,” and this descrip-
tion has been copied by subsequent authors. Examination of
authentic specimens shows however that the asci are constantly
bisporous, and the plant, together with that on Foeniculum vulgare
from Algeria, described by Trabut and Saccardo as A. lichenoides,
present no distinguishing characters from Æ. taurica.

In the Revue Mycologique for 1889 Sorokine published the
following new species of Erysiphe from Central Asia (Turkestan) ;
E. Saxaouli on Haloxylon Ammodendron, E. armata on Malva
sp.; E. alhagi on Alhagi camelorum, and E. pegani on Peganum
Hamala. 1 have not been able to see authentic specimens of
these plants, but from the descriptions and figures given by Soro-
kine, I have little hesitation in referring them all to Æ. taurica.
I have seen an Zrysiphe (representing probably Æ. pegani and E.
Saraouli) on Peganum Hamala and Haloxylon Ammodendron
from Turkestan, which is certainly Æ. taurica ; as regards Æ. alagi
Komarow reports Æ. taurica on Alhagi camelorum. Komarow
(206, p. 275), who has collected since in the same region as Soro-
kine did, has already expressed the opinion that these three
species were founded on immature examples of Æ. taurica.

Since the above notes were written, Magnus (233) has pub-
lished as new species, under the names of Ervsiphe lanata and
Microsphaera Bornmuelleriana, two plants occurring ‘respectively
on Euphorbia lanata and Acanthophyllum glandulosum, collected
by Bornmiiller in Persia. Both these plants I refer to E taurica,

E. lanata is thus described: “ Diese schöne Erysiphe bildet

ERYSIPHE 219

einen dichten weissen filzigen Mehlthau auf der Euphorbia lanata
Sieb. Die Perithecien haben 120-150 » Durchmesser ; sie haben
nur an der Basis ganz kurze, flockige, hyaline Appendiculae von
der Lange etwa eines Drittels des Durchmessers der Perithecien ;
diese enthalten sehr zahlreiche Asci, 20 und mehr. Der Ascus
enthalt drei oder vier oder auch fiinf Sporen (mehr habe ich nicht
gesehen, konnten aber recht wohl auftreten). Die Ascosporen
sind oval, 27 » lang und 13.5 p breit."

I am indebted to Professor Magnus for kindly sending me the
type specimens of Æ. lanata and M. Bornmuelleriana for exam-
ination.

The size of the perithecia of Æ. lanata is somewhat larger than
that given in the description, as in mature examples it is usually
190-210 4. The asci, also, appear to be constantly bisporous.
In some of the unripe asci there are, besides the two young spores,
one or two drops of oily matter; in the ripe ascus, however, only
2 large spores were observed. If more than 2 spores do occur, it
is certainly only very rarely ; and in the habit, large perithecia,
with very numerous large asci the plant on Euphorbia lanata
agrees perfectly with Æ. /azrzca. On looking over the specimens
of Euphorbia lanata in the Kew Phanerogamic Herbarium, I found
plants, on three sheets, more or less covered with the present fun-
gus. The first plant came from Persia, “ prov. Tarsistan, ad.
Persepolis, c. 1600 m. s. m." (Bornmiller, Iter Persico-turcicum
1892-3, 4675) ; the two others from Syria, one labelled “ Rel-
iquiae Mailleanae no. 1675 " ; the other collected by Sir J. D.
Hooker and Mr. D. Hanbury in 1860. There is also a fungus in
the Kew Herbarium labelled “ S. Castagnei ad. Euphorb. sp. nr.
Kellal, 10,000 Pers. austr. (Prof. C. Haussknect, Iter orientale,
1868)" This proves on examination to be Æ. taurica, and is ap-
parently the same plant as that to which Magnus (233, p. 100)
refers.

M. Bornmuelleriana is thus described: ‘ Diese schóne Joo:
sphaera ist durch den Charakter ihrer Appendiculae sehr ausgezeich-
net. Der Durchmesser der Perithecium schwankt von 147-231 #,
ist durchschnittlich 197 #. Sie sind an ihrer Basis von einem dich-
teren Kranze von Appendiculae umgeben, deren Hóhe etwa die den
Durchmesser der Perithecien erreicht. Die Appendiculae sind in

990 A MONOGRAPH OF THE ERYSIPHACEAE

der für Mierosphaera charakteristischen Weise zwei bis drei Male
dichotom oder trichotom getheilt und ihre letzten Enden sind zart
und lang schlauchfórmig verlàngert, wie das auch bei der nord-
amerikanischen Microsphaera Van-bruntiana Ger. auf Sambucus
Canadensis der Fall ist. Während aber bei allen anderen Micro-
sphaera-Arten, die ich kenne, die Appendiculae einzeln frei von
einander vom Perithecien abstehen, verflechten sie sich hier zu
einem dichten Filze mit einander, der die Basis des Peritheciums
umgibt und die Perithecien etwa emporhebt. Während sonst die
Verzweigungen der wiederholt dichotom getheilten Appendiculae
von Microsphaera starr sind, bleiben eben hier die langen schlauch-
formigen Endzweige der Appendiculae zart und hyalin, und ver-
flecten sich etwas gekrauselt durch einander. Die Perithecien en-
thalten zahlreiche Asci. Im Ascus wurden 4-6 Sporen beobachtet,
manchmal in einem Ascus zwei grosse und zwei kleine, offenbar
abortirende Sporen. Die Ascosporen sind oval, etwa 30 y lang
und ron breit.”

This plant is certainly not a Microsphaera, but belongs to Zry-
siphe, and in my opinion cannot be separated from Æ. taurica. It
has no points of resemblance whatever with Microsphaera Van-
Bruntiana (M. grossulariae). The branching of the much-inter-
woven appendages is quite vague and ill-defined, and similar to
that found in Æ. zaurica on other hosts. Even in “ M. Bornmuel-
leriana ” the appendages are not by any means always 2-3 times
di-trichotomous, but are frequently only once or twice vaguely
branched (see Figs. 145, 146, 147). Just thesame kind of vague
branching is found in some appendages of * E, Janata” on Eu-
phorbia (see Fig. 148). Further, in all the perithecia which I have
examined, the asci are bisporous, and the whole habit of the plant,
the large “ pezizoid ” perithecia, large asci and spores, etc., are
quite characteristic of E taurica.

Erysiphe intertexta Berk. mss. in Herb. Kew on Capparis sp.,
“between Lama Yara and the Phatu Pass, 1848, Dr. Thomson,”
is E. taurica.

In mycelial characters Æ. zaurica is extremely variable, and
there is no doubt that it is partly due to this fact that the species
has been described under so many different names. When per-
sistent, the mycelium varies from felted tomentose to crustaceous

ERYSIPHE 221

or lichenoid ; its color is usually white, but sometimes (as on Cap-
paris herbacea, Clematis songarica) it shows here and there patches
of a pale buff color, at these spots the mycelium somewhat re-
sembles thin washleather. Sometimes, however, the mycelium is
completely evanescent, as Léveillé, indeed, pointed out in 1851.
We sometimes find on a plant whose leaves are for the most part
entirely covered with densely compacted persistent mycelium,
some leaves here and there on which there is no trace of mycelium,
the perithecia occurring quite naked on their surface; also on
some plants which have a dense covering of stellate hairs on the
leaves (e. g., Verbascum Blattaria, V. phlomoides, Phlomis Herba-
venti) the mycelium is apparently never persistent,

The persistent mycelium and large subimmersed perithecia
give to E graminis an external resemblance to the present species,
but E zaurica is most closely allied to E cechoracearum ; indeed,
occasionally certain forms of the latter species on Arctium show a
slight approach towards Æ. Zaurica.

Komarow (206, p. 277) notes that in Seravschan (Turkestan)
at the height of 6,000 feet Æ. taurica is one of the most widely-
spread species, up to 4,000—5,000 feet, occurring on almost all the
plants of the steppes, but that higher than 6,000 feet the fungus
does not occur, although several of its hosts ascend to a higher
altitude.

E. taurica has been reported from Asiatic Siberia on Achillea
Ptarmica, but the specimens I have seen from there all belong to
E. cichoracearum. Léveillé (214, p. 162) gives Cnicus eriophorus
as a host-plant for Æ. taurica, but a specimen so named in Léveillé's
handwriting in Montagne's herbarium, on this host, is Æ. cichora-
cearum.

The conidia of E taurica are very large; in examples on
Euphorbia and Acanthophyllum they frequently measure 50 x 18 p.

7. E. AGGREGATA (Peck) Farl. [Fig. 144].
Erysiphella aggregata Peck, Reg. Rep. 28: 63. pl. 2. f. 1-3
1875; Sace. Syll Fung. 1: 23. 1962.
Erysiphe aggregata (Peck) Farl. Bull. Buss. Instit. 2: 227.
1878; Burr. Ell. and Everh. N. Amer. Pyren. 14. 1892.
Exsicc. Seym. & Earle, Econ. Fung. 168; de Thuem. Myc.

232 A MONOGRAPH OF THE ERYSIPHACEAE

Univ. 753, 754, *Eli. & Everh. Fung. Columb. 222 oh, &
Everh. N. Amer. Fung. 2763.

mphigenous ; mycelium evanescent or here and there per-
sistent, at first white becoming yellowish, perithecia more or less
densely gregarious, sometimes very crowded and forming a crust-
like covering, globose-depressed, variable in size, 130-230 pin
diameter, usually about 180 p; cells 10-15 wide, usually 10 p,
often obscure; appendages numerous, densely interwoven, from
equaling to 2-4 times exceeding the diameter of the perithecium
or less branched, irregularly swollen and bent at intervals, at first
thin-walled and septate, becoming thick-walled towards base ;
asci numerous, usually about 20, but sometimes as many as 42,
from ovate-oblong to more or less cylindrical, large, 80-115 x
30-40 #; spores 8, rarely 7, very rarely 6, somewhat roundish,
16-20 x 10-15 p, usually about 18 x 12 H.

Host.—On female catkins of alder; Alnus incana, A. serru-
lata, A. viridis.

Distribution —NoRTH AMERICA : United States—New Hamp-
shire, Massachusetts, New York, New Jersey, Pennsylvania,
Canada, New Brunswick, Ontario,

Peck (279, p. 63) originally published the present species as
the type of a new genus, with the following description : ** Ery-
siphella nov. gen., perithecia destitute of appendages, spores def-
inite. This genus differs from Perisporium in having a definite
number of spores in an ascus, and from Uncinula, Microsphaera
and Zrysiphe in being destitute of appendages.”

The present species really possesses, however, as Farlow (i23)
has already pointed out, very numerous appendages, and is cer- `
tainly to be referred to the genus Erysiphe. The appendages are
more or less densely interwoven, forming usually a pulvinate mass
at the base of the perithecium, and are somewhat easily broken
off, so that often on quite old perithecia only the broken ends are
to be found, or sometimes even these are not to be seen.

Although distinct in its curious habitat on the female catkins of
alders, E. aggregata morphologically must be considered very
close to E polygoni, from which it differs only in the large peri-
thecia, and larger, more numerous, subcylindrical asci, The eight
roundish spores give a characteristic appearance at first sight to A.
aggregata, but just the same shaped spores are found in the in-

ERYSIPHE 223

teresting form (occurring on young twigs of Alnus incana in Fin-
land) published as a distinct species, Æ. vernalis, by Karsten, but
which I have felt compelled to regard as only a form of Æ. poły-
gon. E. aggregata can be separated from this form on the
twigs of Alnus in Europe only by the larger average size of |
the perithecia and asci, and the greater number of the latter— _
characters of not very high specific importance. It is quite pos-
sible, I think, that Æ. aggregata may have to be considered only
a well-marked variety of Æ. polygoni, rather than a distinct species.
Valuable evidence on this point might perhaps be obtainable from
the experiment of sowing conidia of E. aggregata on host plants
of Æ. polygoni, or conversely by infecting alder catkins with the
conidia of Æ. polygoni.

8. E. TRINA Harko. [Figs. 141, 142]

Erysiphe (Erysiphella) trina Harkn. Bull. Calif. Acad. Sci. 1: 41.
1886 ; Sacc. Syll. Fung. Addit. ad Vol. L-IV.: 3. 1886; 9: 370.
1891; Burr. in Ell. & Everh. N. Amer Pyren. 14. 1892.

Exsicc.:: Ell. & Everh. N. Amer. Fung. 2337 ; * Ell. & Everh.
Fung. Columb. 23.

Epiphyllous ; mycelium persistent, effused or forming irregular
patches ; perithecia minute, at first yellow, becoming yellowish-
brown, globose, more or less gregarious, small, 52—60 p» in diam-
eter, averaging 55, cells at first evident, 8-10 p wide, soon be-
coming indistinct as the wall becomes semi-transparent ; appendages
usually 3 or 4, short and very rudimentary, sometimes apparently
absent; asci 3, very rarely 2, brodly ovate to subglobose, with or
without a minute stalk, 48-50 x 28-36 a; spores 2, large, some-
times slightly curved, 25-34 x 14-164

Host.—Quercus agrifolia.

Distribution —NORTH AMERICA : United States—California.

E. trina is a very marked and interesting species, only known
at present from California, on the single host-plant Quercus agri-
folia. The perithecia are very small, and yellowish-brown at ma-
turity ; the outer wall is very thin, membranaceous, and semitrans-
parent, so that the outline of the large spores is clearly visible in
the unopened perithecium (see Fig. 141). Although described as
without appendages, there are usually a few rudimentary ones
present at the base of the perithecium.

224 A MONOGRAPH OF THE ERYSIPHACEAE

Sub-family PHYLLACTINIEAE Palla.

Mycelium not sending haustoria into the epidermal cells of
the host plant, but forming special branches of limited growth,
which pass through the stomata into the intercellular spaces of
the leaf. Each of these intercellular hyphae sends a single haus-
torium into the cells of the surrounding tissue (spongy paren-
chyma).

One genus, Phyllactinia.

PuyrracrINiA Lév. Ann. sci. nat. III. 15: 144. 1851.

Perithecia large, globose-depressed to lenticular, asci many, 2-
or rarely 3-spored. True appendages equatorial, rigid, acicular,
with a bulbous base; apex of perithecium provided with a mass
of densely crowded branched outgrowths from the epidermal
cells. Etym. q»32ov, folium, and axctz, radius. Distrib. Europe,
Africa, Asia, North, South and Central America.—1 species.

Phyllactinia is known at once by the large perithecia and the
rigid colorless acicular appendages with a bulbous base.

PHYLLACTINIA CORYLEA (Pers.) Karst. [Figs. 163-175 |

Sclerotium Erysiphe Pers. Obs. Myc. 1: 13 (partim). 1796.

S. Erysiphe B corylea Pers. Syn. Fung. 124. 1801; Alb.
& Schwein. Consp. Fung. Lusat. 76, 1805.

S. suffultum Rebent. Prod. Fl. Neomarch. 360; A. 3. J. 14.
1804.

Erysiphe coryli Hedw. f. ex DC. Fl. Fr. 2: 172. 1805.

£. fraxini DC. Fl. Fr. 2: 273. INO S

Dematium Erysiphe Spreng. Fl. Hal. 387. 1806.

Erysiphe alni DC. Syn. Pl. Fl. Gall. 57. 1806; DC. Lam.
Enc. Méth. (Bot.) 8: 219. 1808; DC. Fl. Fr. 6: 104. 1815.

E. oxyacanthae DC. Secret. Mycogr. Suisse, 3: 655 (syn. excl.
partim). 1833; Cast. Cat. Pl. Mars. 190. 1845.

E. betulae DC. Fl. Fr. 6: 107. 1815; Duby, Bot. Gall. 2:
870. 1830.

E. varium Fr. Obs. Myc. 1: 206 (partim). 1815; 2: 366
(partim). 1818.

E. varium, var. suffultum Fr. Obs. Mye, 31 906, 1815,

E. vagans Biv. Bern. Stirp. rar. Sic. man. SI MN. s. f. 3.
1815.
Erysibe pachypus Mart. Fl. Crypt. Erlang. 393. 1817.

ERYSIPHE 225

E. suffulta (Reb.) N. v. Esenb. Syst. Pilz. Schw. 148. ai rg.
134. 1817; Ueberbl. des Syst. 38. 1817.
Alphitomorpha guttata Wallr. Berl. Ges. Nat. Freund. Verhand.

Th

I: 42 (excl. syn. Æ. salicis DCH, 1819; Wallr. Ann. Wett. Ges.
4: 245 (excl. syn. E salicis DC.) 1819; Wallr. Fl. Crypt. Germ.
2: 760. 1833.

Erysibe orbiculatus Ehrenb. N. Act. Acad. Leop. Car. Nat.
Cur. 10: 203. M. 12. 1821; Lk., Willd. Sp. Pl-6: if$.- i824.

E. alni DC., Gray. Nat. Arr. Brit. Pl. 1: 589. 1821.

E. guttata, var. fagi (Wallr.) Ficin. and Schub. FI. Gegend.
Dresd: a: 305. 1823.

E. guttata Lk., Willd. Sp. Pl 6: 116. 1824; Rabenh.
Deutschl. Krypt. Fl. 1: 234. 1844.

Erysiphe guttata Fr. Syst. Myc. 3: 245. 1829; Duby, Bot.
Gall. 2: 871. 1830; Berk., Sm. Engl. Fl.5: 327. 1836; Tul.
Sel. Fung. Carp. 1: 194. A. r. 1861; de Bary, Beitr. Morphol.
Phys. Pilz. 1, § XIII. 52. . 1870.

E. detonsa Fr. Syst. Myc. 3: 247. 1829.

E. mali Duby, Bot. Gall. 2: 869. 1830.

E. fagi Duby, Bot. Gall. 2: 871. 1830.

E. abnormis Duby, Bot. Gall. 2: 871. 1830.

E. roboris Gachet, Act. Soc. Linn. Bord. I. 5: 227.: 1838,

Alphitomorpha lenticularis: Wallr. Fl. Crypt. Germ. 2: 759.
1833.

Erysibe coryli Wahlb. Fl. Suec. 2: 1086. 1833.

Erysiphe lenticularis Kickx, Fl. Crypt. Env. Louv. 1 39. 1835.

E. quercus Mér. Rev. Fl. Par. 459. 1843.

Erysibe lenticularis Rabenh. Deutschl. Krypt PL ri 234
1844.
Erysiphe nivea Cast. Cat. Pl. Mars. 190. 1845.

E. pyri Cast. Cat. Pl. Mars. 190. 1845.

E. ilicis Cast. Cat. Pl. Mars. 191 (syn. excl). 1845.

E. cerasi Cast. Cat. Pl. Mars. 191. 1845.

Erysibe lenticularis, var. carpini Desmaz. Ann. sci. nat. III. 3 :
361. 1845. :

Erysiphe aceris Westend. Herb. Crypt. Belg. nr. 551 (cum diag.).

E. marissali Westend. Bull. Acad. Roy. Belg. 18: 403. pl 7.
Jed iB. ij

226 A MONOGRAPH OF THE ERYSIPHACEAE

E. guttata, var. mespili Cast. Supp. Cat. Pl. Mars. 53. 1851.

Phyllactima guttata Lev Ann. sci. nat. III. 15: 144. X.
A. if. 1851 7 Gomke, Micr. Fung:: 218. Al. 17. f. 219, 220.
1865; Cooke, Handb Brit Fung. 2: 646. f. 373. 1871;
Karst. Myc. Fenn. 2: 197. 1873.

P. Candolla Ley Ann. sci. nat. III. 15: 150. 2. 7. f. 72.
1853 y Sacc. Syll. Kung. E: 5... 1882.

P. suffulta (Reb.) Sacc. Mich. 2: 50. 1880; Sacc. Syll. Fung.
I: 5. 1882; Oudem. Rev. Pyren. 11. 1884; Wint., Rabenh.
Krypt. Fl. Deutschl. 17: 42. 1884; Burr. & Earle, Bull. Ill.
State Lab. Nat. Hist. 2: 411. f. 6. 1887; Speg. Fung. Pat. 34.
1887; Atkins. Journ. Elisha Mitch. Soc. 7: 68. pl. 2. 1891;
Burr., Ell. & Everh. N. Amer. Pyren. 20. ai 3. 1892; Schroet.,
Cohn's Krypt. Fl. Schles. 3: 246. 1893; Jacz. Bull. l'Herb.
Boiss. 4: 736. 1896; Oudem. Rév. Champ. Pays.-Bas, 2: 85.
1897.

P. corylea (Pers.) Karst. Act. Soc. Faun. Fl. Fenn. 2: 92.
1885.

P. antarctica Speg. Fung. Pat. 34. 1887; Sacc. Syll. Fung.
: 366. 1891.

P. suffulta, var. macrospora Atkins. Journ. Elisha Mitch. Soc.
4:58. 1891,

Erysiphella Carestiana Sacc. Malpighia, 11: 282. 1897 ; Sacc.
Syll. Fung. 14: 463. 1899.

Phyllactinia berberidis Palla, Bericht. Deutsch. Botan. Gesell.
17: 05. pl. 5. 1899.

Exsicc. Bri. & Cav. Fung. par. 11, 170; Rab. Fung. Eur. 166,
440, 1052, 1053, 1054, 1055, 1056, 1148, 1519, 2028; Sacc.
Myc. Ven. 67, 620, 621, 622, 623, 624, 625, 894, 895, 1377; Fckl.
Fung. Rhen. 702, 703, 704, 705, 706, 707, 708, 709, 710, 764;
de Thüm. Fung. austr. 124, 124b, 123, 125, 127, 128, 120, 445,
446, 855 ; Rav. Fung. Amer. exsicc. 85, 86, 623, 624; Roumeg.
Fung. gall exsicc. 1071, 1570, 2418, 2449, 2734, 3520, 3737;
4756; Cooke, Fung. Brit Exsicc. * 92, 598; ed. sec. 598; de
Thüm. Myc. univ. 137, 158, 1939; and 846 sub Microsphaera
penicillata ; Oudem. Fung. Neerl. Exsicc. 162, 163; Rab. Herb.
myc. ed. 2, 461, * 462, 463; Lib. Pl. Crypt. Ard. fasc. 1, 82;
Westend. Herb. Crypt. Belg. 413, 658, 739; Kunze, Fung. select.

o

ERYSIPHE 227

exsicc. 59, 235; Desmaz. Pl. Crypt. Fr. ed. 1, ser. 1, 167, 1307,
1308, 1519, 2199, 2200, *ed. 2, ser. I, 112, 707, 708, 1019,
1849; Syd. Myc. March. 239, 245, 433, *3673, * 3723;
Jack, Lein, u. Stizenb. Krypt. Bad. 247, 555; Rab.-Wint. Fung.
Eur. 3047, 3048,.3049; Baxt. Stirp. Crypt. Oxon. fasc. 2, 96;
Fl. Exsicc. Austr.-Hung. 381 ; Roumeg. Fung. Select. Gall. Ex-
sicc. 260; Ell. N. Amer. Fung. 1327; Berk. Brit. Fung. 205;
Moug. and Nestl. Stirp. Crypt. Vosges, 83; Vize, Fung. Brit.
92; Fl. Gall. et Germ. Exsicc. 1200; Rehm, Ascom. 797 ; Wint.
Fung. helvet. Supp. 86, 87 (in Herb. Earle); *Seym. and Earle,
Econ. Fung. 142, 143, 153,177; * Erikss. Fung. par scand. 139a,
139b ; * Kneiff. and Hartm. Pl. Crypt. Bad. 56, 162; * Funck,
Crypt. Gewach. Fichtenb. 123 ; * Wartm. and Schenk, Schweiz.
Krypt. 14, 422, 423 ; Erb. Critt. Ital. ser. 1, * 191, * 594 ; et 591 in
Herb. Mus. Florence ; * ser. 2, 836, 837 ; * Hoppe, Fung. Epiph.
15, 16; * Wartm. and Wint. Schweiz. Krypt. 724, 823; Klotzsch,
Herb. Myc. 180 (in Herb. Upsala Mus.); * Wagn. Crypt. Herb.
Biel. 10; * Gandog. Fl. Alger. exsicc. 1982; * Romell. Fung.
exsicc. praes. scand. 61; * Ell. and Everh. Fung. Columb. 108.

Usually hypophyllous, very rarely amphigenous ; mycelium
often evanescent, but sometimes more or less persistent, and then
thin and effused, or rarely forming definite patches ; perithecia
usually scattered, but sometimes gregarious, large, globose- de-
pressed to lenticular, 140-270 p in diameter, or rarely reaching to
350 w in diameter, cells rather obscure, 15-20 # wide, apex of
perithecium provided with a mass of densely crowded special out-
growths from the external cells, each outgrowth when mature ter-
minating in a fascicled head of numerous short hyphal branches,
which, when the perithecium becomes turned over, grow more or
less mucilaginous and fix the perithecium upside down to the
substratum ; true appendages equatorial, usually from 5-18, oc-
casionally as many as 25, I-3 times the diameter of the perithe-
cium, acicular, rigid, straight or occasionally slightly flexuose
towards the apex, aseptate, colorless or very rarely yellowish-
brown at the apex, swollen at the base into a hollow bulb; asci
5—45, subcylindrical be Gi Seier 60-105 x 25-40 p, very
rarely as large as 120 x 50 p, more or less stalked; spores 2,
rarely 3 (4 recorded baten authors), variable in size, sometimes
curved or rather irregular in shape and larger at one end than at
the other, 30-42 y, rarely reaching to 50 #, x 16-25 sr, when 3,
smaller, about 24 x I4 p.

228 A MONOGRAPH OF THE ERYSIPHACEAE

Flosts.—Acer campestre (214) (263) (272) (387), A. platanoides
(272), A. Pseudo-Platanus, A. saccharinum (97), Actinidia arguta,
Alnus glutinosa, A. glutinosa x incana, A. incana and var. vires-
cens, A. maritima, A. rubra, A. serrulata, Amelanchier Canadensis,
Anarthrophyllum rigidum (336), Angelica syluestris, Artemisia vul-
garıs, Asclepias Syriaca (280), Berberis vulgaris, Betula alba, B.
lutea (153), B. nana, B. nigra, B. occidentalis, B. papyracea,
Broussonetia papyrifera, Buxus sempervirens (41), Carpinus Ameri-
cana, C. Betulus, Carya sp. (97), Castanea dentata (249), C. sativa
and var. Americana, Catalpa bignonioides, C. speciosa, Celastrus
scandens, Cephalanthus occidentalis, Chelone glabra (324), Chionan-
thus Virginica (214) Clematis Vitalba (130), Colliguaja Brasiliensis
(335), Cornus Amomum, C. candidissima (280), C. circinata (280),
C. florida, C. Mas, C. Nuttallii, C. sanguinea, C. stolonifera, Cory-
lus Americana, C. Avellana and var. /aciniata, C. Colurna, C. ros-
trata, C. tubulosa, Cotoneaster sp., Crataegus coccinea, C. Crus-galli
(280), C. occidentalis, C. Oxyacantha, C. rivularis, C. sanguinea
(349), C. tomentosa and var. pyrifolia, Desmodium Canadense (60),
Elsholtzia (273), Erythrina sp., Euonymus Europaeus (22), Fagus
ferruginea (61) (97) (280) (324), F. sylvatica, Fragaria sp., Frax-
inus Americana, F. excelsior and var. diversifolia, F. Mandshurica,
F. Ornus, F. oxyphylla (214), F. pubescens, F. quadrangulata, F.
. sambucifolia, F. viridis, Hamamelis Japonica, H. Virginiana (97)
(153) (163), Heuchera parvifolia (6), Hippophaé rhamnoides, Hu-

mulus Lupulus (230), Dex decidua, Juglans (130), Liriodendron
Tulipifera, Lonicera Caprifolium, L. Xylosteum, Magnolia acuminata
(280), M. Fraseri (249), M. Kobus, Mercurialis perennis, Morus
. alba, Negundo aceroides (151), Nyssa sp., Olea Europaea (41),
Ostrya Virginica, Paliurus aculeatus, Parmentiera alata, Paulownia
imperialis, Philadelphus Lewisti, Prunus Americana (371), P. Avium
(214), P. Cerasus, Pyrus amygdaliformis, P. communis, P. Ger-
mania, P. torminalis (214), Quereus aquatica, Q. Catesbaei, QO.
coccifera (396), Q. coccinea and var. tinctoria, Q. discolor, Q. falcata,
Q. Ilex, Q. Kelloggü, Q. macrocarpa, Q. nigra, Q. palustris, Q.
Phellos (12) (371), Q. Robur, Q. rubra, Rhamnus alpina, Rhododen-
dron (Azalea) sp., Ribes Cynosbati, R. Grossularia, R. Magellani-
cum (336), Rubus fruticosus (3) Salix sp., S. Caprea (214), Sam-
bucus sp. (130), S. nigra (214) (293) (316), Syringa vulgaris (290);

ERYSIPHE 229

Tanacetum vulgare, Typha latifolia (5),UImus alata, U. Americana,
U. campestris, U. montana, Vaccinium stamineum, Vitis Labrusca
(36), Xanthoxylum Americanum.

Distribution.—Evrore: Britain, France, Portugal (396), Bel-
- gium, Netherlands, Germany, Switzerland, Italy, Austria-Hungary,
Denmark, Norway, Sweden, Finland, Russia.

ArRICA: Algeria.

Asta: Turkey (Aleppo), Transcaucasia (338), Siberia (Minus-
sinsk) (235), China (Yun-nan) (273), Japan.

SOUTH AMERICA: Paraguay (335), Patagonia (336), Tierra
del Fuego (337).

CENTRAL AMERICA: Guatemala.

NORTH AMERICA : Mexico; United States—New Hamp-
shire, Massachusetts, Connecticut, New York, Pennsylvania, West
Virginia, South Carolina, Ohio, Michigan, Indiana, Alabama, Illi-
nois, Mississippi, Wisconsin, Missouri, Iowa, Minnesota (325),
South Dakota (151), Kansas (386), Montana, Wyoming, Cali-
fornia, Washington ; Canada— Ontario, Newfoundland.

Phyllactinia corylea is the most sharply characterized and one
of the most widely spread species of the Erysiphaceae. The large
size of the perithecium, and the acicular appendages with a bulbous
base, enable the present species to be easily recognized, usually
with the naked eye.

Nevertheless, as will be seen from the synonomy, P. corylea
has had many names given to it. This has been due partly to the
fact that the appendages are either very fragile or deciduous, and
so the fungus under different conditions has been supposed to
belong to different species; for the most part, however, these
names owe their origin to the fact that P. corv/ea grows on a very
large number of hosts, and in former times the occurrence of a
species of mildew on a new host-plant usually led to the descrip-
tion of the fungus as a new species.

There can be no doubt, when sufficient material is examined,
that only a single species of PAy//actimia exists. Whether on its
numerous hosts in America (where Burrill states that “ scarcely a
deciduous-leafed tree seems proof against it "), whether on Par-
menticra alata in Guatemala, Erythrina in Mexico, on Morus alba
and Paulownia imperialis in Japan, or on the Cupuliferae of Europe,

230 A MONOGRAPH OF THE ERYSIPHACEAE

the variations that occur are never important enough to make us
doubt that we are dealing with one cosmopolitan species, able to
live not only on a great number of different trees, but also, ap-
parently, on some herbs (see list of host-plants above).

I have united P. Candollei Lév., P. antarctica Speg., and P.
berberidis Palla with the present species.

Léveillé described P. Candollei from specimens occurring on
the leaves of a species of Nyssa in North America, and remarked
(214, p. 150), "Cette espèce ressemble à la précédente [P. corylea];
la seule difference repose dans les sporanges, qui sont au nombre
de huit et qui renferment quatre spores au lieu de deux." I have
examined two specimens of Léveillé's plant; one in Berkeley's
Herbarium at Kew, the other in Montagne's Herbarium in the
Paris Museum; both specimens are named in Léveillé's handwriting.
Many of the asci in these specimens were found to be 2-spored
(in one perithecium all the asci were bisporous), but most con-
tained 3 spores; I did not observe 4 spores in any. The asci
were frequently above 8 in number, in one case being as numerous
as 18; this character, however, is not important, as there are often
less than 8 asci in undoubted examples of P. corylea. The two
examples showed no other differences, and there is therefore no
reason to consider “ P, Candollei”’ as more than a mere form of
P. corylea with frequently 3 (or even, perhaps, sometimes 4) spores
in the ascus. It is curious that Phy//actinia has not been reported
on Nyssa since Léveillés time. The specimen on which Berkeley's
record of “ P.. Candollei,’ from Canada (Poe), in Grevillea, 4: 158.
1876, was based, agrees in every way with P. corylea.

I have not been able to see a specimen of P. antarctica Speg.,
found on Ribes Magellanicum in Patagonia, but from the description
given have no hesitation in referring it to P. corylea. Spegazzini
records: “ P. suffulta (Reb.) Sacc. [ P. corylea] as occurring on
Anarthrophyllum rigidum from the same region, and gives a good
description of the fungus. Speggazzini's diagnosis of P. antarctica,
however, applies better to the more usual form of D corylea than
does his diagnosis of the form of “ P. suffulta" mentioned above,
and there can be no doubt that both specimens are referable to P.
corylea.

P. berberidis Palla is a very interesting form. In Palla's valu-

ERYSIPHE 231

able paper mentioned above, the Phvllactinia growing on bar-
berry leaves is described as a new species under this name.
The author remarks (264, p. 64) that “ die Phydlactinia der Ber-
beritzenblätter zwar sehr nahe der P. suffulta der Haselnussblätter
steht, sich aber von ihr constant vor allem durch die an der Spitze
stark gebräunten Perithecien-Anhängsel unterscheidet und dem-
nach als eine eigene Art anzusprechen ist." At page 56 (loc. cit.)
the same character is more closely described: ‘An ihrer Spitze .
sind die vollkommen ausgebildeten Anhängsel bei P. suffulta
ziemlich stark verschmalert und häufig etwas geschlängelt ; die
abgestorbenen Plasmareste sind stets farblos und reichen sehr oft
nicht bis in das Ende der zart-wandigen Spitze hinein, an der nicht
selten das Anhängsel collabirt erscheint. Bei P. derberidis sind
die Anhàngsel an der Spitze nur wenig verschmälert ; die hier
vorhandenen abgestorbenen Plasmareste sind immer mehr minder
stark gebräunt und gehen bis in das Spitzen-ende hinein ; meist
erstreckt sich die Färbung auf das ganze obere Drittel, und nicht
selten reicht sie bis zur Mitte des Anhängsels herab.”

The brown celor of the protoplasmic contents of the apex of
the appendages is probably best seen in living plants ; and becomes
partly lost in dried material. In the dried specimens (now in the
Kew Herbarium) kindly sent to me by Dr. Palla, the apex of the
appendages is yellow-brown, and the appendage has the appear-
ance shown at Fig. 171 (cf. M. 5. f. 2 of Dr. Palla's article).

The other minor differences described as existing between the
perithecia of P. berberidis and P. corylea certainly do not hold
good when dealing with the numerous forms of the latter—as
perhaps might be expected from the author’s statement that only
examples of P. corylea occurring on Corylus in Austria were taken
into consideration in making the comparison.

With regard to the value that should be attached to the pres-
ence of the colored tips of the appendages it seems to me very
probable that the color is to be considered as wholly due to the
influence of the particular host on the fungus. We know that the
barberry contains a yellow coloring matter (berberin), and I am
inclined to attribute to the effect of this substance on the fungus
not only the colored tips of the appendages, but also the very
bright yellow color of the asci and spores. With regard to these

232 A MoNOGRAPH OF THE ERYSIPHACEAE

highly colored asci and spores there is every appearance of the
condition being a pathological one.

On the whole, it appears best to consider the Phyllactinia on
Berberis as a form slightly affected by certain peculiarities of the
host-plant, and not morphologically distinct from P. corylea.

Dr. Palla is mistaken in stating that PAyllactinia had not pre-
viously been reported on Berberis. Saccardo has distributed
specimens from Italy (Sacc. Myc. Ven. 895, Phyllactinia guttata,
f. Berberis vulgaris); Passerini (272), and many other authors
have recorded it from other places in Europe, and Berkeley (35),
Farlow (122), Burrill (60), etc., report it from America.

Erysiphella Carestiana was described by Saccardo as being
destitute of appendages, and consequently referable to the genus
named. Professor Saccardo very kindly sent me the type-speci-
men for examination. The fungus is 7. corylea; some of the
perithecia have lost their appendages, but some show a few perfect
ones, and many have retained a ring of the bulbous bases of the ap-
pendages. The fungus was recorded. as growing on the damp
pileus of Fomes fomentarius, but there is now. every reason, I
think, for believing that it did not originate there. Certainly the.
perithecia adhere firmly to the pileus of the Fomes, but there is as
regards the present species, clear evidence for disregarding mere
attachment as a proof that the fungus originally grew there. Dr.
Palla, when sending me specimens of the Phyllactinia on Berberis,
wrote that the fungus was always hypophyllous, and mentioned that
the perithecia which were to be found on the upper surface of the
leaves sent, owed their presence there to the pressure of the under
sides of other leaves. Without such warning, one would certainly
have considered these perithecia as originally growing on the
upper surface of the leaf, for they were firmly attached to the sub-
stratum, and like the specimens on the pileus of the Fomes re-
quired some little force to move them with a needle.

This reattachment of the perithecium is brought about by the
mucilaginous branches of certain special apical outgrowths. In
the case of the Phyllactinia on the Fomes, Professor Saccardo
states (52) that the pileus of the “ host -fungus was moist; this
favors the idea that a reattachment by means of the mucilaginous
branches had taken place. I am glad to be able to state that

ERYSIPHE 233

.
Professor Saccardo now agrees with the view that the position of
Lhyllactinia on the Fomes is in all probability an accidental one.

Hitherto the presence of attached perithecia on a leaf has nat-
urally been considered as conclusive proof that the fungus orig-
inated there, but for the reasons mentioned above, such proof now
becomes invalid. ‚It is therefore very desirable that the reported
occurrences of P. corylea on herbs should be investigated in the
field, as it is impossible to prove from the examination of her-
barium specimens (unless perithecia can be observed springing
from a mycelium) if the fungus originated on the plant in question.
An observation of Fuckel’s (133, p. 80) perhaps refers to this
reattachment of perithecia. This author remarks “ dass die Peri-
thecien auf in der Nahe stehende Pflanzen, wie Graser usw. ueber-
wucherten. Dasselbe mag wohl auch der Fall sein mit jenen,
welche Bagge auf Pertusaria fand.”

Professor Miyabe has sent me specimens (now in the Kew
Herbarium) of a very beautiful form of P. corylea from Japan,
growing on Paulownia imperialis. The form is remarkable for its
large size. Many of the perithecia reach a diameter of 350 4;
the appendages are more numerous than usual, being sometimes
as many as 25, when they are arranged so closely round the peri-
thecium that their bulbous bases touch one another. In these
perithecia the asci and spores show, likewise, a tendency to be
larger than usual. Intermixed with these large perithecia, how-
ever, are others which, in the smaller size of all their parts, agree
perfectly in every respect with ordinary P. corylea. Altogether,
we cannot consider that the Phy/lactinia on Paulownia is anything
but a luxuriant form of P. corylea, which it would be inadvisable
to separate even as a variety. It is most probable that further
search on other Japanese plants would bring to light a complete
series of forms of Phyllactinia intermediate in size between this
large form on Paulownia and those of normal size.

Since writing the above, I have noticed that Atkinson (9) has
described a form of Phyllactinia occurring on certain American
oaks (Quercus Phellos, Q. nigra) as variety macrospora. The
form, from the description, is evidently comparable to the Japanese
plant mentioned above. The perithecia, apparently, are not so
large (200-250 # in diameter), but the very large asci, reaching

234 A MONOGRAPH OF THE ERYSIPHACEAE

to 120 x 50 5, and spores 35-50 y long, are similar to those of
the Japanese form. Both, I feel convinced, are to be considered
as merely large forms of P. corylea, quite unable to be separated
systematically.

Erysiphe detonsa Fries is, in all probability, the present species,
as Léveillé has contended (214, p. 145). Inthe Friesian Herbarium
there is a specimen named “ E. detonsa” in Fries’ handwriting,
and this is certainly P. corylea. This specimen occurs on the
wood of Fraxinus, however, and is, therefore, not the type which
is described in Syst. Myc. as growing on Tanacetum vulgare. I
have seen the specimens on Tanacetum vulgare (in Montagne's
Herbarium at the Paris Museum), which Léveillé has stated came
from the same source as those on which Fries founded his species,
and find that these also belong, as Léveillé has said, to P. corylea.
It is true Fries says of his plant “ peridiolo solitario" ; with the
exception of this character, however, the description applies well
to imperfect examples of 7. corylea, and it is to be noted that
Fries says ''Peridia . . . facie E guffatae." The fungus identi-
fied by Kickx as Fries E detonsa is the Sphaerotheca called
S. humult, var. fuliginea (see Sacc. Syll. Fung. r: 4; also
Oudem. Rév. Champ. Pays-Bas, 2: 84-85.

In the description of P. corylea above it is mentioned that the
perithecia possess a mass of special apical outgrowths. The nature
of these outgrowths has been until quite recently completely mis-
understood. Each outgrowth, which springs from the external face
of a cell of the outer wall of the perithecium, consists of a stalk-
cell (Fig. 173, a), bearing a terminal mass of densely-clustered,
short, swollen, more or less tubular branches (Fig. 173, ^). Some-
times the stalk cells branches irregularly before giving rise to the
branches. Ata certain stage of development, the branches of each
outgrowth become mucilaginous, and their separate walls more or
less indistinguishable (Fig. 174, @). Inthis mucilaginous condition,
the outgrowths which arise in a dense mass from the apical cells,
cause the firm attachment of the perithecium to the substratum.
During the process of this mucilaginous degeneration, the walls of
the hyphal branches become more or less dissolved and are invis-
ible without staining, while the protoplasmic contents of each
branch remain distinct, especially toward the apex (Fig. 175); at

ERYSIPHE 235

this stage each outgrowth has much the appearance of a stem-cell
bearing a number of stalked spores. An interesting point in con-
nection with these apical outgrowths is the power they possess,
after the perithecium on which they occur has been detached from
its original substratum, of again becoming mucilaginous and so
causing the reattachment of the perithecium to foreign objects. As
mentioned above, the occurrence of P. corylea on the pileus of
Fomes fomentarius is probably to be accounted for in this way, and
the same explanation is perhaps to be given to many of the re-
corded cases of the occurrence of P. cory/ea on herbaceous plants.

The explanations given of the apical outgrowths by previous
authors have been very different. Nägeli (256) described the
structures as a parasitic fungus under the name of Schinzia penicillata
(afterwards changed to Waegelia penicillata by Rabenhorst) Bon-
orden (49) stated that they were part of the fungus, but that they
sprang from the inner wall of the perithecium and surrounded the
asci. Tulasne (369 and 370) fully described the outgrowths, and
placed these structures on the organic apex of the perithecium (see
370, tab. r). Vuillemin (379) repeated Bonorden’s error of sup-
posing that the structures originated internally.

Quite recently, however, Neger (258) has published a prelimi-
nary note on Phyllactinia, in which the author attributes to the
outgrowths the function of anchoring the perithecium to the leaf;
the conclusion to which I had already arrived from the study of a
large amount of herbarium materials from all parts of the world
(see Journ. of Botany (314), where a more complete account of the
views of previous authors on the nature of the outgrowths is given).
In this article I stated that the penicillate cells spring from the
base of the perithecium. In a paper by Dr. Neger (Bericht.
Deutsch. Botan. Gesell. 17: 235-242. fl. 23. 1900) appearing
shortly afterwards, the author, from the study of living specimens,
described and figured these outgrowths as springing from the
apex of the perithecium. This led me ‘to reéxamine perithecia,
with the result that I found Dr. Neger's statement to be perfectly
correct. I can only suppose that in the section from which the
Fig. 6 (Journ. of Bot.) was drawn, the asci were really loose, and
dragged round in the process of cutting. The firm attachment of
the perithecium by the outgrowths also led me at that time to

236 "A MONOGRAPH OF THE ERYSIPHACEAE

think that the latter sprang from,the organic base of the perithe-
cium, whereas as Dr. Neger (7. c.) has shown, the perithecium,
when so fixed, is really turned upside down. Neger has briefly
mentioned that ina Phyl/actinia from the Argentine examined by
him the outgrowths were characterized by a much-branched stalk-
cell, and on this account the author regards the fungus as a new
species of Phyllactinia, and proposes the name P. c/avariaeforuus.
As a full description and figures of the plant are promised, the
question of its specific distinctness must be left open until these
appear, although as I have already pointed out (314, p. 453. f. 3)
the validity.of the character relied upon seems doubtful.

Richon (298) describes a fungus which. attacks the leaves and
stems of Poa nemoralis and Festuca sylvatica, and gives the name
“ Erysiphe graminis? DC." to the plant, but remarks: ‘Les
périthéces soul ornés de 6 ou 8 appendices, simples et renflés à la
base. Il constitue probablement une variété de Phyllactinia suf-
fulta non signalée par les auteurs et différente de /' Erysiphe gram-
imis de Saccardo.” It will be well to ascertain if the Phyllactinia
was actually growing on the plants mentioned, before adding
grasses to the list of the host-plants of the species.

P. corylea is sometimes mentioned among the diseases attack-
ing cultivated nut trees, but I have found no statement that it has
ever caused any serious injury. Pammel (268, p. 103) mentions
that Phyllactinia “ occurred destructively on Fraximus,” at Ames,
Iowa.

DOUBTFUL OR EXCLUDED SPECIES

Erysiphe radiosum Fr. Obs. Myc. 1: 207. 1815 = Actino-
nema 1osae (Lib.) Fr.

E. album Fr. l. c. No specimen seen.

Alphitomorpha rosarum Wallr. Ann. Wett. Ges. 4: 238.
1819. No specimen seen. Wallroth gave the following descrip-
tion: “A subiculo subtilissimo fere obsoleto, sporangiis parvis
sparsis sphaericis, capillitio obsoleto. Hypophylla in Rosa cinna-
momed, rarior. Species ob minutiem sporangiorum facile praeter-
videnda, nec quoque subiculo detegenda, quod cum tomento folii
obductum est. Dubiam igitur modo indico." In Fl Crypt.

Germ. 2: 755. 1833. Wallroth placed it as a variety under
“A. penicillata”

ERYSIPHE 237

4A. epigaea Wallr. Berl. Ges. Nat. Freund. Verhandl. 1: 44.
1819; and Ann. Wett. Ges. 4: 246. 1819. From the descrip-
tion given there is no doubt that this fungus is to be placed out-
side the Erysiphaceae, as Dietrich (107, p. 343) has already re-
marked. Karsten (194) considers it the ‘sclerotium-stage” of
Lanosa nivalis Fr.

A. epixylon Schlect. Berl. Ges. Nat. Freund. Verh. 1: 50.
1819. No specimen seen.

Erysibe acariforme (Sow.) Gray, Nat. Arr. Brit. Pl. 1: 590.
1821 = Hypoxylon coccineum Bull.

E. Sowerbit Gray, l. c. = Coprinus radiens (Desm.) Fr.

Erysiphe Tordylii Chev. Fl. Par. 1: 380. 1826. On Tordylium
maximum. No specimen seen; very probably Æ. polygoni.

Erysibe Wallr. Fl. Crypt. Germ. 2: 198-218. 1833. All
the species of this genus belong to the Uredineae (Uredo, Ustilago,
Puccinia, Tilletia, etc.).

Erysiphe lathyri Mer. Rev. Fl. Par. 459. 1843. On Lathyrus
latifolius. No specimen seen.

E. saxifragae sibericae Mer. l. c. On Saxifraga Siberica.
No specimens seen.

E. tiliae Mér. /.c. On the lime. No specimens seen.

Phyllactinia Schweinitzii Lev. Ann. sci. nat. III. 15: 150. pl
7.f. 13. 1851; Sacc. Syll. Fung. 1: 6. 1882. Leéveillé made
two sections of his genus Phyllactinia—one characterized by the
bulbous appendages, the other described as possessing “ Appen-
diculae nigrae vesicula basilari destitutae." The latter contained
only P. Schweinitzü, described as follows: “ Hypophylla. My-
celio arachnoideo evanido. Conceptaculis magnis, sparsis, hemi-
sphaericis, demum depressis. Sporangiis . . . sporis . . . ap-
pendiculis nigris. Hab. Meudon, ad folia Quercus sessiliflorae.
Obs. J'aurais dü passer sous silence cette espéce, comme je l'ai fait
de beaucoup d'autres dout je n'ai pas vu la fructification, mais je
ne le pouvais pas; ses appendicules solides, noires et dépourvues
de vésicules à la base lui impriment un caractére particulier qui
empéche de la confondre avec aucune autre espéce connue jusqu'à
ce jour.” Nothing further has been known about this species
since Léveillé's time, and I have not been able to find any exam-
ple among the specimens of Erysiphaceae sent by Léveillé to

238 A MONOGRAPH OF THE ERYSIPHACEAE

various authors. From the description of the appendages the
plant evidently does not belong to the genus Phyllactinia—very
probably not to the Erysiphaceae at all. The diagnosis given,
however, is much too incomplete to admit of an identification of
the plant, and if, as seems to be the case, no specimens exist,. the
name should be dropped.

Erysiphe nervisequia Westend. Bull. Acad. Roy. Belg. 21:
231. 1854. Westendorp’s description is as follows: ‘ Subicule
nul, peridium punctiforme, trés-petit (1/10° de mille de diamétre),
globuleux, d’abord orangé, puis brun et enfin noir, luisant, atta-
ché par quelques fibrilles rares au support et contenant un seul
péridiole globuleux—Cette espece, qui forme des lignes pointillées
sur les nervures de la feuille . . . se developpe sur les deux faces
des feuilles du Stachys palustris.’ Namur, Belgium. I have
seen specimens from Westendorp’s herbarium (as well as others
sent to me by Professor Pàque as Erysiphe communis var. labia-
tarum), and find that the fungus does not belong to the Ery-
siphaceae. The perithecia are from 70-80 yp in diameter, rather
irregular in shape, but more or less globose-depressed, with a
fragile, membranous wall composed of small rather distinct dark
brown cells, 4-5 # wide. The perithecia occur scattered sparingly
on both sides of the leaf, and also occasionally in denser patches
on the stem. The so-called *'péridiole"' js in reality a multicel-
lular structure, and is perhaps the separating inner wall of the
perithecium. Within this oval or spherical structure, some bodies
which resembled very young asci were observed, but none of the
` material examined was ripe enough to allow of the generic identi-
fication of the fungus. It seems probably, however, that the
plant will prove to belong to the Eurotieae.

Erysibe andreaeacearum and E. chroolepidis Reinsch. Contrib.
Algol. et Fungol. 96 (1874-5) belong to the Algae. Hariot
(Journ. de Bot. 3: 405. 1889) states that the latter species is
Trentepohlia Monilia de Wildem. (see however, Magnus, 230).

? Phyllactinia fungicola (Schulz.) Sacc. Syll Fung. 1: 6.
1882. Erysiphe fungicola Schulz. Oest. Bot. Zeit. 26: 58. 1876.

Saccardo gives the following diagnosis: “ Peritheciis brunneo-
fuscis, sphaericis, 300 f diam., subiculo mucedineo stellatim
effuso insidentibus ; conidiis in hyphis acrogenis brunneis ; appen-

j

ERYSIPHE 239

dicibus radiatis, basi inflatis; ascis vesicularibus, copiosis, 1—2-
sporis; sporidiis ovato-cylindraceis, 4x 1.5. Hab. In superficie
Boleti duriusculi Slavonia.—Videtur Phyllactiniae species, sed ob
habitationem insuetam dubia. Turning to Schulzer, we find this
description ` ** Ervsiphe fungicola Schlzr. fand ich gegen Ende
Oktober, im Nustarer Walde bei Vinkovce, zerstreut auf der
Oberflàche meines Boletus duriusculus im erkrankten Zustande.
Die Pyrenien sind schwarzbraun, kuglich, dann am Scheitel ein-
sinkend, 0.3 mm. breit. . . . Sie sitzen, jede für sich, auf einen
aus strahlenformigen kiirzeren und langeren Hyphen bestehenden
Mycelium. Die längeren, unter sich von fast gleicher Grösse,
verdicken sich an der Spitze und es entsteht eine einfache oder
einmal septirte, braune, später abfallende Conidie oder Chlamy-
dospore, während der Faden selbst ungefärbt ist. Weiter oben
gehen vom Pyrenium in geringer Zahl steif-radienförmige an der
Basis blasig erweiterte Fulcri mit einfacher Spitze ab. Ihre
Länge beträgt beilàufig den doppelten Pyrenium-Durchmesser.”

The asci and spores are described as in Saccardo’s translation,
except that the size of the latter is stated to be 40x15 p.
Although the characters of the occasional septation and the brown
color of the spores do not fit Phyllactinia corylea, Schultzer’s de-
scription in other respects seems to point to this species. P.
corylea has been recorded lately as occurring on the pileus of Fomes
Jomentarius, but in this case the occurrence of the Phyllactinia was
merely accidental. .In the case of "E fungicola,” the presence
of mycelium and conidia indicate (if these really were in connec-
tion with the perithecia) that the fungus originated on the Boletus.

Erysiphe ? scandens Ernst (Monatsch. Ver. Beförd. Gart. preuss.
Staat. 1878 : 400)=Pellicularia Koleroga Cooke (see Grevillea, 9 :
IO. 1880).

Microsphaera Bresadolae (Quel.) Bres. in litt., Sacc. Syll. Fung.
9: 368. 1891; Podosphaera Bresadolae Quélet in Bresad. Fung.
Trid. 25. JL 30. f. 2. 1881. Quélet's description is as follows:
“ Perithecia globosa, membranacea, superficialia, sparsa, minutis-
sima, late reticulata, e luteolo rufescentia, demum nigricantia, 90
mmm. diam. ; appendiculae hyalinae, perithecio duplo majores,
apicibus ie dichotomo ramosis praeditae; asci subglobosi,
8-spori, mox evanidi, 50 mmm., sporae ovatae, luteolae, echinu-

240 A MONOGRAPH OF THE ERYSIPHACEAE

latae, 15-20x 12 mmm. Autumno. In pileo Arrheniae auriscal-
pium Fr. in sylvis umbrosis mixtis. Val di Sole. Podosphaera
clandestinae Lev. affinis." Saccardo gives the same description
and adds “ascis . . . in quoque perithecio pluribus. . . . Etsi.
matrix tam absona, species generis optima videtur." In Quélet's
figure a perithecium is shown with appendages which certainly
recall those of the genus Microsphaera. On the other hand, the
echinulate yellowish spores, if these are correctly described, would
be anomalous characters. Overlooking these spore characters,
the suggestion may perhaps be made that perithecia of some spe-
cies of Microsphaera, e. g., M. alni, may have accidentally become
attached to the pileus of the Arrhenia. Abbe Bresadola informs
me that unfortunately the type specimen is lost.

BIBLIOGRAPHY 241

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242 A MONOGRAPH OF THE ERYSIPHACEAE

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386. Walters, L. A. Er detta of Riley County, Kansas. Trans.
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387. garen G. D. "Not. sur quelq. Crypt. inéd. ou nouv., etc.
Bull. Acad. roy. Belgique, 18: 403. 1851.

388. ër? £31: 231. 1884

389. Wettstein, R. v. In Stapf's Die bot. Ergebn. der Polak. Exped.
nach Persien, I: 4. 1885.
go ———— Vor E zu ein. Pilzfl. Steiermark. Verh. k. k. zool.-bot.
Gesell. Wien, ee 578-580. 1886.

L. c. 38: 196,197. 1888.

` Whitehead, c. Fifty Years of Hop Farming. Journ. Roy.

in Soc. England, III. 1: 334, 335. 1890.

393- Hop Cultivation. Z. c. 4: 246-249. 1893.

394. Winter, G. Die Pilze, in Rabenhorst’s Krypt. Flora von
Deutschland, Oesterr. und der Schweiz. I’: 22-42. 1884.

Contrib. ad. flor. myc. lusitan. ser. v. Bol. Soc. Brot.
4:30. t $198

390. Se L. t. 3: 54. 1888.

397- Contrib. para o estudo da Flora d'Africa; Fungi. Z. c.
3: i: 3866:

398. Wolff, R. Keimung der Ascosporen von Zrysiphe graminis Lév.
Bot. Zeit. 183, 184. 1874.

— Beitrag. zur Kenntn. der Schmarotzerpilze (Zrysiphe
graminis und E. communis), 1-39. pl. 3, 4. 1875.

400. Zeitsch. für Pflanzenkrankheiten 1: 28. 1891; 4: 335. 1894.

=

395-

260 A MONOGRAPH OF THE ERYSIPHACEAE

EXPLANATION OF PLATES
( Unless otherwise stated, all figures are magnified 400 times )
PEATE T
Figs. 1-14. Microsphaera alni, apex of the appendage in different forms of the
species. I, from a specimen on rita ue es md 2, on Gleditschia sags sine
(from the type specimen of “ M. Ravenelii”’); 3, on Viburnum Opulus . peni-
cillata,’’ from specimen from mie: s herb.); 4, 5, 6, on Cornus eh (from
the type MERCURE of ** M. pulchra’’); 7, on Castanea un 8, on Betula alba
“M. Friesri," from specimen from Léveillé's herb.); 9, 10, on ** erineum’ *-galls on
the leaf of Fagus ferruginea (“ M. erineophila”’ jn on d emopanthes fascicularis
(**M. Nemopanthis’’); 12, on Viburnum Lantana (** M. Hedu wigii, from specimen
from Léveillé's herb. Nr I3, I4, on SE occidentalis (from the type specimen
of “M. semitosta’’),
15-17. M. alni var. rege dos apex of E appendages.
ne. 18. M. alni var. extensa, apex of an append
I9, 20. M. alni var. lonicerae en irme named ** JZ, Dubyi"' from
Leib s herb. E
Figs. 21, 22. M. alni var. lonicerae (from specimen named “ Ar Ehrenbergii " ).
Figs. Aa M. alni var. divaricata, apex of three appendages,

PLATE 2
Fig. 26. M. alni var. divaricata, apex of an append
Figs. 27-30. M. alni var. ludens, apex of four mor i
Figs. 31-33. M. diffusa, apex of three appendages, 31, from specimen on Desmo-
dium, Wisconsin; 32, from type specimen of M. di 7ffusa ; 33, from specimen on Sym-
phoricarpos racemosus (**M. sy mphoricarpi’ GE

Figs. 34-37. M. grossulariae ; a 35, apex of two appendages from European
specimens on Ribes grossularia ; 37, part of the outer wall of the perithecium, from
same specimens, 36, apex of an appendage (immature) from an American specimen on

Sambucus ( “M. Van-Bruntiana"
Figs. 38, 39. M. Russellii, apex of two appendages.
Figs. 40, 41. M. berberidis, apex of two appendages.
Fig. 42. M. guarinonii, half of the apex of an appendage.

PLATE 3
Fig. 43. Af. dite oni mature Des of an appendage, from an American speci-
men on Sambucus (** M. Van-Bruntiana Un.
Fig. 44. M. guarinonii, apex of a nearly mature appendag
Figs. 45, 46. d" ve apex of an appendage, ascus and ascospore.
Figs. 47-51. M. astraga guttas apex of four appendages, 5I, part of perithecium,

Figs. 52-55. 7. Bau sad apex E two appendages, ascus and ascospores.
Figs. 56-58. M. ferruginea, apex of two appendages, ascus and ascospore.
Figs. 59, 60. M. Mougeotii, apex of an nit. and ascus.
Fig. 61. Uncinula australis, asci and ascospore:
igs. 62, 63. “U. Gester Bea ascus and ascospores (from type
specimen).

EXPLANATION OF PLATES 261

PLATE 4
Figs. 64-68. U. Sengotui ; 64, perithecium with appendages, X er = 66, three
appendages ; 67, asci and ascospores; 68, part of outer wall of perithec

Figs. 69-72. U. fraxini; 69, perithecium with appendages X 1 egg en single ap-

pendages, and the apex of three others; 71, asci and ascospores; 72, part of wall of
perithecium.

Figs. 73-78. U. salicts var. Miyabei, 73, perithecium with appendages, X 150;

4, 75, three appendages; 76, 77, branched apex of two appendages; 78, asci and
es;

PLATE 5
Figs. ^i 80. U. prunastri, appendages, asci and ascopores.
Figs. 81, 82. U. Clintonii, appendages, asci and ascopores
Figs. s T 4. o exuosa, two append and erin co

nidium.
Fig icis, helicoid apex of Cep ege from specimen on Populus
odio hoi U. pe iformis’?
Fig. 86. U. necator, base of an appendage, showing abnormal enlargement, from

—

specimen on Actinidia from Japan.

Fig. 87. U. aceris, apex of five appendages (a, slightly flattened ).

Fig. 88. U. Delavayi, asci and ascospores.

Fig. 89. U. polychaeta, asci and ascopores,

Figs. 90, 92. Ordium-like fungus ae with the mycelium of U. aceris, var.
Tulasnet ; 90, conidiophores ; d conidia.

Fig. 91. Odium occurrin one same leaf with the above.

g.

Figs. 94, 95. C. Ge two appendages, asci and puo ge

Figs. 96, 97. ee oxyacanthae, appendage from European specimen on
Crataegus Oxyacantha ; a, b, c, successive stages in the Meier. of the young ap-
pendage.

Fig. 98. P. biuncinata, apex of three appendages.

PLATE 6

Figs. 99-108. P. oxyacanthae, apex of appendages and asch ; 99, 100, from spec-
imens on Pyrus Aucuparia (** P. aucupariae’’); 101, 102, from Aneticen specimens ;
103, erg specimens on Pyrus Germanica (** P. Clandestina’’ ex herb. Léveillé);
105, from specimen on Spiraea M ( ** Microsphaera fulvofulcra » 106, 107,
108, three asci, showing variation in size.

Figs. 109-114. P. See var. ¢ridactyla, apex of appendages, ascus and
ascospores.

Fig; HE 2. eheu conidial ( O/dium) stage showing conidiophore and
conidia.

Figs. 116, 117. Sphaerotheca humuli (on Spiraea ulmaria), conidial ( Oidium)
stage (116, portion o d a leaf, showing mycelium and five conidiophores, X 150; 117,
o^ Sid our onidia).

118. vede: Schlechtendalii, ascus and ascospores.

PLATE 7
Figs. 119-122. Folsphuers leucotricha ; 119, 120, two ge with apical and
basal appendages, X 95; , ascus and ascospores; 122, branched apex of two ap-

pendages.

262 A MONOGRAPH OF THE ERYSIPHACEAE

Fig. 123. P. Schlechtendalii, apex of two appendag

Figs. 124-126. Sphaerotheca gegen 124, er artificially burst open,
forcing out the ascus and the inner wall, X 255; 125, portion of the inner wall; 126,
ascus and seen ES

127-129. Erysiphe galeopsidis on Stachys sylvatica ; 127, conidiophores and

ssa: re 129, hyphae, showing lobed haustoria (128 X 980).

Fig. 130. Lobed haustoria of Erysiphe on Eupatorium ageratoides, X 670.

Figs. 131. Haustoria of Ærysiphe A on Sonchus arvensis, X 670.

Figs. 132-139. E. polygoni; 132, asci (a typical Isis ; 133, from specimen on

Lupinus ; 134, from specimen on Ger lanceolatus; 135-139, ascospores; 135, from
ecimen on Polygonum ; 1 Ps on Circaea en: 137, on Lupinus ; 138, on Cnicus
lanceolatus ; 139, on Parnassia Carolini

Fig. 140. 2. WË (on A en conidiophore and conidia; a, 4, c, d,
successive stages in the development of the young conidiophore
à PLATE 8
Figs. 141, 142. Erysiphe trina; ae two p I42, ascus and ascospores.
Fig. 143. Asci and ascospores of * E, vernalis,

Fig. 144. E aggregata, two

Figs. 145-150, 152-154. Æ. taurica ; 145-147, 149, mm appendages and ascus,
from the type specimens of ** Mier data ee '; 148, 150, two append-
ages and ascus from the type specimen of ** E. Janata EE 7 153, ascus and ascospores

from berg from Léveillé’s herbarium; 1 m ascus of ** E. papilionacearum.”’
Fig. - E. cichoracearum, asci and as
Fig. er E. polygoni on Polygonum guides: section showing a hypha of the
nee forming a haustorium in an epidermal cell, X 670.
156. E. graminis, on Hordeum, conidial stage ( Oidium monilioides).

PLATE 9
Fig. 157. E. poly goni var. sepulta ; asci es.
eg 158. E. polygoni, on Donnie glauca; ascus and ascospores.
160. EZ. graminis A Ku two asci, with 8 spores formed in each, from
the specimen in Rab. Fung. Eur. ; 160, two asci (from European examples).
g. 161. ** Oidium pipi t pues (from specimen from Montagne's her-
berum) í
Fig. 162. ** O, Balsamii’’ on turni ps (W. G. Smith in herb. Cooke).
Figs. 163-175. Ph ee corylea ; section of leaf of Berberis vulgaris, showing
a special hypha (** Ernihrungshyphe "') of the se passing through a stoma into
the intercellular spaces, and sending a hausterium into a cell of the spongy parenchyma
(the lower half of the hypha is seen passing behind some Weg in an intercellular space );
164, ascus from Japanese specimen on acte: alba ; 165, ascus and ascospores from Jap-
ese specimen on Paulownia imperialis ; 166, ascus with three spores (from specimen
of ** P. Candollei”’ from Léveillé's ed ) ; 167-169, ascus and ascospores; 170-172,

degeneration) ; 175, apex of one Ge the branches of an 1 outgrowth, at the stage when
the we i is partly disso I ved and invisible without staining, protoplasmic contents evi-
70.

HosT-InDEx 263

HOST-INDEX
Records for plants prefixed by * (before the generic or specific name) have not been
personally verified ; the authority for these will be found indicated in the list of host-
plants given under the species in question. . = Erysiphe, M. = Microsphaera ;
P. corylea = Phyllactinia ; P. = Podosphaera ; S.— Sphaerotheca ; U. — Uncinula.
Acanthophyllum glandulosm E. taurica.
Acer campestre U. aceris
* corylea.
A. dasycarpum U. circinata.
A. pessul U. aceris an
var. Tulasnei
*A. P yl U. circinata.
A. pictum U. aceris.
A. platanoides U. aceris and
var. Tulasnei
* EE corylea.
A. Pseudo-p!atanu U. aceris and
corylea
* u J. aceris var. Tulasnei.
A. rubrum U. circinata
* E j U. aceris,
A. saccharinum U. circinata.
si E P. corylea
A. spicatum ..U. circinata and :
U. aceris.
A, Tataricum U. aceris
Achillea Millefolium, Ptarmica E cichoracearum
i E. polygoni
= H E. taurica.

Aconitum *Anthora, Fischeri, Napellus, *paniculatum......... E. polygoni.

Actaea spicata

Actinidia arguta : U. necator and P. corylea
A. Kolomikta, polygama U. necat

Actinomeris squarrosa : ^x eese.
Adenocaulon bicolor on var. SCH

E. cichoracearum.
E r

Aesculus *arguta, *flava, gn Hippocastanum, Pavia...... P flexuosa.
Aethusa Cynapium......... E. polygoni.
Agrimonia Eupatoria S. humuli.

Agropyron *caninum, glaucum, repens, scabrum, *tenerum..E. graminis.
is *alba, *exarat +

Aaus sp U. Delav
Ajuga ciliata.... nk var. fuliginea.
*A reptans E polygoni.

264 A MONOGRAPH OF THE ERYSIPHACEAE

Albizzia oplhantha 2s e
Alchemilla arvensis, vulgaris S. humuli.
Alhagi *camelorum, maurorum E. taurica.
Alnus glutinosa M. alni and P. corylea.
“ X incana P. corylea.
A. incana P. corylea, E. aggregata,
polygoni (vernalis)
M. alni and U. salicis
var. Miyabei.
A. incana var. virescens M =. and. P. —

A. maritima

and U. salicis var. Mi-

yabei.
A. rubra M. alni and P. corylea.
DI ae

A. serrulata

and E. aggregata.
nd

A. viridis M. alni a
E. -a

*Alopecurus agrestis.. ERA gram

Althaea ficifolia, Kurdica E. tauri

lyssum calycinum, *campestre E Gig
Ambrosia artemisixfolia, psilostachya, trifida and var. integri-

folia E. cich earum

*Amelanchier alnifolia E. polygoni.

A. Canadensis P. oxyacanthae and
corylea.

*A. maculatum ygoni.

* Ampelopsis cuspidata U. necator
Amphicarpaea Edgeworthii var. Japonica, monoica ............E. polygoni
Amsinckia spectabilis E cichoracearum

AE cots ky corylea
*Anchusa Italica E. cichoracearum.
e officinalis polygoni.
ic E. cichoracearu
nada sp. M. alni var. vaccinii.
Anemone dichotoma, *ranunculoides, *thalictroides, Virgini-
polygoni
Angelien sylvestris P. corylea and
E. polygoni.
Anthriscus Cerefolium, sylvestris ....E. polygoni.
Antirrhinum Orontium E. cichoracearum.
T E. polygoni.
ra Spica-venti graminis.
viae aspera U. polycheta and
; à U. Clintonii
Apios tuberosa M. diffusa and M. alni.
„Aplopappus Ss ji E. cichoracearum.
*Apocynum sp
Aquilegia RE vulgaris. E. polygoni.

Host—INDEx

*Arabis alpina

265

S. ** Castagnei."'

SA. Turrita

Archangelica officinalis

E. polygoni,
oe

rctium maj jus,

E

A. minus

A. nemorosum

rum and S.
humili var. fuliginea.
E. taurica and

E. cichoracearum.

E est s

Arenaria deep *juniperina

ristotelia racemosa

E polyg

Arnica cordifolia, montana
* A ] } avena cenm

ep densa
S. humuli var. fuliginea,

aminis.

Artemisia Absinthium, *biennis, campestris, *discolor, dra-

cunculoides

Dracunculus

> cichoracearum.
taurica,

A.
A. EN Japonica, Ludoviciana and var. gnaphalodes, =

E. cichoracearum,

g
A. eloo
*

P. corylea
U. salicis.

ER Syriaca..
A. variegata

L0

perugo procumbens

E. cichoracearum.
[73

Aspe
— odora

DI

E. polygoni.

*Aster adscendens

*A. Bellidiastrum

E. cichoracearum.
** Castagnei.”’

A. canescens, communis, commutatus

.
cichoracearum

*A. commutatus

E. polygoni.

A. nspicuus, ioe *corymbosus,
Bon ericoides and var. *villosus, eas var, "eg
i, *grandi , *junceus, laevis and var. laevi-
gatus, longifolius, ek hyllus, *multiflorus, *oblongi-
olius, paniculatus, prenanthoides, puniceus, sagittifolius,
*salicifolius, *Shortii, Tradescanti, *umbellatus, *vimineus
var, reg sus E. cichoracearum.
Astragalus sp. E, taurica.
A. adsurgens E

DÉI

SC Zoe

A. al pinus

E od var. fuliginea.

A. baeticus, caespitosus, Canadensis, *caryocarpus............. E. polygoni
SA. Cicer
A. Cooperi M. euphorbiae.
*A. decumbens E ly
Drummondii M. euphorbiae
frigidus var. d Gebleri E. polygoni,
" Glycyphyllos......... M. astragali
A. *Gl ig Ae *hypoglottis, *junceus, Lamberti...........E. polygoni.
A. Mortoni M. euphorbiae.

266 A MONOGRAPH OF THE ERYSIPHACEAE

*A. multiflorus E. polygoni.
ZA. Onobrychis M. astragali. `
A. oroboides var. Americanus, reflexistipulus, *triphyllus,
irrigatus E. polygoni.
Avena *fatua, sativa E. graminis.
un nigra E. galeopsidis.
DÉI

E. cichoracearum
alsamorhiza sagittata "
oO

Baptisia tinctoria E. polygoni.
Bartsia Odontites S humuli var. fuliginea.
kmannia erucaeformis E ien nis.
*Bellis annua E. tortil
erberis Aquifolium M Sethetiale:
B. vulgaris M. berberidis and
P. corylea,
E alba M. alni and P. corylea.
i U. salicis.
B. URS bii PR ees M. alni.
B. * lutea, nana, nigra, occidentalis, papyracea P. corleay.
*B. pumila. alni.
Bidens cernua, ch tl , connata, frondosa, tripartita.S. humuli var. fuliginea,
Bigelowia graveolens and var. albicaulis E. polygoni var
sepulta.
B. deca: ..E. cichoracearum.
Bolton Bun LU Meo RA We
"me i i

Brassica Rapa, *Sinapistrum, een th he iis polygoni.
PPS EBD Getae rca escis E
Bromus *asper, bre eviaristatus, armen re wën,

loides

alinus, sterilis, *tectorum, *unio «ss I». giaminis.
Broussonetia pap ifera P. corylea.
KM a TO ar e
* S es U. salic
eg Eege, ere EL S; bumuli var. maa
Ee ey
* & d meant E A E.
C. officinalis..... ....... es. humuli var. zen
bel EE E E. cichoracearum
* = ee ee dt E S de E. polygoni,
irn gruen ce N EL LER ^
jpg NI UE ebd eun ee S. “ Castagnei.’’
E E. polygoni.
ER E E. cichoracearum
See E. polygoni
ee... taurica,
E 2 in dass

SEENEN awe, Cichoracearum.
A ; «E. polygoni

MEM. Torr. Bor. CLUB, 9. PL

E. 8. SALMON, DELT.

THE HELIOTYPE PRINTING CO., BOSTON

Mem. Torr. Bor. CLUB, 9. PR

E. 8. SALMON, DELT.

THE HELIOTYPE PRINTING CO., BOSTON

Mem. Torr. Bor. CLUB, 9.

E. 8. SALMON, DELT.

rog pr cu ec e UE

Mem. Torr. Bor, CLUB, 9. Pr. 4.

E. 8. SALMON, DELT.

| THE HELIOTYPE PRINTING CO., BOSTON

Mem. Torr. BoT. CLUB, 9.

Pr. 6.

MEM. Torr. Bor. CLUB, 9.

E. 8, SALMON, DELT.

THE HELIOTYPE PRINTING CO., BOSTON

Mem. Torr. Bor. CLUB, 9.

E. 8. SALMON, DELT,

THE HELIOTYPE PRINTING CO., BOSTON

Mem. Torr. Bor. CLUB, 9.

THE HELIOTYPE PRINTING CO., BOSTON

Mem. Torr. Bor. CLUB, 9.

THE HELIOTYPE PRINTING CO., BOSTON

: Host—INDEX

C, acanthoides

267

E. cichoracearum.

E taurica
E

crispus
C. geren *viridis

*Carlina acaulis

E. este lanata

E. taurica

*C, vulga:

S. ** Castagnei.’’

re abrotanoides

ee S. humuli var. fuliginea.

Carpinus Americana
* [73 D

P. corylea.
M

C. Betulus

Carthamus lanatus

*Carum Persicum

*Carya sp

C. alba, sulcata

*Cassia Chamaecrista

TRNA dentata

E. polygoni.
M. alni.

C. sativa, and var. weier?

var. Japonica

corylea
P. corylea p M. alni.
M. alni

Geng bignonioides, speciosa

M Wetz var. vaccinii and

C, syringaefolia

Caucalis Japonica

P. corylea.
E. polygoni.
ee

Ceanothus Americanus

Celastrus articulatus

C. scandens
* [11

Celtis Americana

C. Mississippiensis
-C, occidentalis

*
C. tal

a
Centaurea *Jacea, nigra, nigrescens, Scabiosa

*C. Scabiosa

M. alni and P. corylea.

Cephalanthus occidentalis
*Cerinthe major

taurica.
E. cichoracearum.

. minor

*
peas aromaticum, aureum, *bulbosum, hirsutum,
*nodosum,

temulum, pesci

Chelone glabra
* DI DÉI

DÉI ee

Chelonopsis moschata
*Chionanthus Virginica

corylea.
E. galeopsidis.
P. corylea

Chondrilla juncea

is villosa

€.
*Cicer Songari cum

taurica.
E. cichoracearum.
taurica.

268 A MonoGRAPH OF THE ERYSIPHACEAE

- Cichorium Intybus E. cichoracearum.
* s & S t5 Castagner."
*Cicuta virosa E. polygoni
*Cimicifuga foetida > e

Circaea Lutetiana T

Clematis alpina and *var. Sibirica, Flammula, fusca var.

Yezoensis, *integrifolia, *leucantha, *ligusticifolia............ e

*C. orientalis E. cichoracearum.

C. recta. E. polygoni. '

E. Songarica E. taurica

C. DUUM Vitalba E. polygoni.
*C. Vitalba P. co

Cnicus altissimus, and var. discolor, *arvensis E. cichoracearum.
*C, arvensis E. taurica.

C. Cardunculus Pë

C. forem eriophorus, heterophyllus, lanceolatus...... = cichoracearum.

C. lanceolat en.

* [23 E. ta

C. oleraceus, *rivularis, undulatus and var. canescens. owes vos rum.

. Weyrichii var. Grayanum S. humuli var. fuliginea.

*Coccinea dubia ae aoe a E. taurica
*Colliguaja B: P. corylea.

Collomia ferus puse i linearis S. humuli.

*C. linearis S. humuli var. fuliginea.

Colutea arborescens ; M. euphorbiae and
oni.

. polygo:
C. cruenta M. euphorbiae.

Conium maculatum E pus
Convolvulus Ammannii, arvensis, sagittatus

Coreopsis aristosa, *aurea, tripteris S. humuli var. —:
*Cornus alba E tortilis

C. alternifolia ni

C. Amonmum... aes P. corylea
EI DI M

C. *candidissima, *circinata, florida P. corylea

C, macrop. ylla M. alni.

C. Mas, Nuttallii, sanguinea P. corylea

C. sanguinea E. tortilis.
C. stolonifera P. corylea
* " M. alni

polygoni
` alni id P. corylea.
C. romam and var. laciniata, Colurna, rostrata .....,.......,, P. imm
C. rostrata and var. Mandshurica..................
Sé PR

Coronilla *Emerus, *varia
lus Americana

rr eee ee *

pene
é4

M. umbilici.
i ce

E. polygoni.

U. prunastri.

*Crataegus sp.
C.*Azarolus, coccinea

C. coccinea

P. oxyacanthae.
P. corylea.

P €

E Crus-galli
*

occidentalis

P. co

C. Oxyacantha, rivularis, *sanguinea

C. spathulata, *subvillosa, tomentosa
E ntosa

orylea.
P. corylea and P oxya-
canthae

P. oxyacanthae.
corylea.

€ var. punctata

LL var. pyri folia

Ty
P. oxyacanthae.
Er and P.

Crepis p paludosa

corylea.
S. humuli var. I.

C. *psludosa, parviflora

E. cichorac

earu
S. humuli var. ine
S Casta. agne

*Cucumis sativus
* [73 DÉI

*Cucurbita maxima

Pepo
T x E Truppen
Më E. ** Castagnei.’’
Cuphea viscosissima E. polygoni

EEUU uso Uo sa ak oe iuncti es "Uaanene ue er rnus E. taurica.
Cynoglossum Morisoni, officinale. E. cichoracearum
*Cytisus purpureus E ni.
Dactylis giomerata E inis.

E. cichoracearum

E

II

Daphne alpina

E. polygoni.

Daucus erandiflorus
S

ee

E. taurica,

D. maximus

UM Ajacis, *azureum, consolida, elatum, formosum,
orum, orientale, *Tiroliense, vestitum

E. polygoni.
E. graminis.

E. polygoni.

: diffusa,

DM.

D. *canescens, Hit paniculatum, sessilifolium...... p di

nc

*Diarthron vesiculosum

^

polygon
S ge var, fuliginea.

la Tapo
LUE od
Dimorphotheca pluvialis

P. oxyacanthae.

*Dipsacu 5 Ful lonum

D. laciniatus

.S. humuli.

D. syl vestris

270 A MoNOGRAPH OF THE ERYSIPHACEAE

* We E. polygoni.
Doronicum Austriacum, *grandiflorum S. humuli var. fuliginea..
*Dorycnium herbaceum.....u.esesesennnsunenenerennennn nnne there E. taurica,
Draba alpina var. glacialis, hirta S. humuli var. fuliginea.
*D. hirta SET NE. E. D olygöni.
in S. humuli var. fuliginea.
piorum yii INE ia *papposa E. cichoracearum
Echinospermum ae SRedowskii, Virginicum............ T
*Echium Italicum er
E. vulgare E. polygon
= A E eg A mae
Elaeoselinum Lagascae ). taurica.
Ellisia Nyctelea E. cichoracearum.
*Elsholtzia sp corylea.
E. cristata E
*Elymus condensatus E. graminis.
Epigaea repens M "d var. vaccinii
Epilobium adenocaulon, alpinum S. hum
E. angustifolium S y else
* DI

U, salicis.
E. cephalostigma, coloratum, hirsutum, jucundum, montanum,
arviflo

alustre, parviflorum, parviflorum X roseum, eegen
seum S. humuli.
*E. tetragonum S Castagnei.’’
* « Tuch im
Erechtites praealt S. humuli var. EES
We e E. polygoni.
Erigeron acris, annuus S. humuli var. ee
*E, armerifolius E cea

Se we S. humuli var, ie
E. *corymbosus, *divaricatus, elatus, *glabellus, macranthus,

*strigosus E. cichoracearum.
Eriogonum nudum E. cichoracearum
Erodium moschatum S. humuli.

Ery ium campestre E. taurica.
B. mscrocalyx. iss .E. polygoni.
*E. Noéanum E. taurica.
Erysimum reca ues *odoratum E. polygoni.
itia P. corylea.
ugenia sp. GE ont U. australis.

“ ea.

*E, verrucosus M ony
Eupatorium ageratoides E. ? galeopsidis
E. cannabinum E. cichoracearu

E S. *' Castagnei.""
E liatum, purpureum E. cichoracearum.

» M. euphorbiae.

Host-Inpex 271

E. dulcis, helioscopia S. mors-uv
E. hypericifolia M euphorbiae
E. lanata E. tauri

M mag" ZS

E. pls, Peplus, platyphyllos S. mors-uvae.
E M. euphorbiae. +
S. mors-uvae.

S humuli var. fuliginea.

E. stricta, *virgata
Euphrasia Kee, s

*Exochor Alberti E. tau
agopyrum esculentum E wv
Fagus *atropunicea, ferruginea Ini. .
*F. ferruginea P. corylea.
F. sylvatica ec
Falcaria vulgaris ... E. polygoni,
DI

Falcata comosa
Fatoua pilosa, var. subcordata

S. humuli var. fuliginea.

Festuca *arundinacea, elatior, *gigantea, *heterophylla...... E. graminis.
Foeniculum vulgare E. taurica.
Forestiera acuminata f. alni
Fragaria sp P. corylea.
F. pad S. hum

S aai var. fuliginea.

Fraxinus Americana, excelsior and var. diversifolia P. corylea.
. longicuspis. U. fraxini,
F. Mandshurica, Ornus, *oxyphylla, pubescens, quadrangu-
lata, sambucifolia, viridis P. corylea
Gaillardia aristata S inis: var, fuliginea.
DÉI DI E. cichoracearum
Galeopsis Tetrahit, versicolor E. galeopsidis.
Galium Aparine E. cichoracearum
DÉI D lyg 1
= boreale E. cichoracearum.
E. polygoni.
G. ES *sylvaticum, E. polygoni.
G. tri E. cichoracearum.
Gaylussacia resinosa M. alni var. vaccinii.
Geranium caespitosum, Carolinianum ENNEN ..S. humuli.
*G, dissectum S. Castagnei.”
A E. polygoni.
G. ibericum, incisum, maculatum S. humuli.
G. maculatum, *molle E. polygoni
SC molle S. ** Castagnei.”’
G. nepalense, palustre, *pratense S. humuli.
G. wee Ke? um *Pyrenaicum... sk dissi euer nn E, polygoni.
G. Richardso S. humu i.
x e E. polygoni.
G. sylvaticum S. humuli
Hi * tuberosum = pol ygoni.

S. humuli var. fuliginea.

Gerardia grandiflora, quercifolia

272

Geum album, Kokanicum, *macrophyllum, strictum....

A MONOGRAPH OF THE ERYSIPHACEAE

E, humuli.

G. urbanum E. polygoni.
* E. cichoracearum.
G. Virginia S. humuli
Gilia Suen PESCH linearis zi
Gleditschia triacanth M. alni.
Glyceria *aquatica, *nervata E. graminis.
Glycyrrhiza lepidota M. diffusa.
Gnaphalium sylvaticum E. cichoracearum.
Örindelie squarrosa =
Gundelia Tournefortii E. taurica.
Gutierrezia Euthamiae E. cichoracearum.
* “ ui E. polygoni
Gymnocladus sp ......... ERLERNEN M. alni.
MI Gmeini E. polygoni
Halox E. taurica
Hamam zeg man P. corylea.
H. Virginiana P. biuncinata.
" .e P. corylea
*Haplophyllum Sieversianum E. taurica
Hedysaru m Falconeri E. taurica.
elenium Keen E. cichoracearum.
*Helianthella Parryi «
Helianthemum Oelandicum E. taurica
H. vulgare S,

Pisia ee EE and var. *Utahensis, doroni-

igant
petiolaris, rigidu
ns

"cm Maximiliani, orgyalis,
strumosus, tuberosus, and var. wb

E

um arenarium

Helichrys
Heracleum ` asperum,

Sphondylium

*flavescens, palmatum,

Sibiricum,

Hesperis matronalis, *tristis

hereto] m

*Heuchera Americana

m parvifolia

Picus

NN rd

H. Stater *boreale, E *incisum, lycopsifolium,

humuli var. fuliginea.

cichoracearum.
ae
polygoni.
ee

corylea.
** Castagnei.’’

humuli var. fuliginea.

urorum, prenanthoid E. cichoracearum.
Rage sabaudum S. '' Castagnei.’’
*vulgatum E. cichoracearum.
mee rhamnoides....... P. corylea. .
REESE. is.
Posen aeneo *murinum, secalinum, vulgare............. mu
Hosackia parvi E polygoni.
Humulus geng Lupulus. S, humuli.
Dt Lupulus E. cichoracearum.
E lea.

“Hyp a

HosT-InDEx

273

H. Canadense, capitatum, *macrophyllum, *occidentale, Vir-

cichoracearu

ginicum
H. Virgi nicum

umuli var. fuliginen.

Hyoscyamus albus, niger

*H. niger

cichoracearum.

Hypericum sep tdg hirsutum

m mb
PO

ar

*H. humifusı

Sei

EE

montanum, perforatum, quadrangulum
1

FE
Ilex decidua

polygo
pate mer M. alni.

I. *mollis, *verticillata

alni
ie Casta agnei,”’
humuli var. fig,

bau pj O0 Oo. iS "d 3

*Inula Britann cichora

I. dysenterica humu il var, i: fag:

I. *Helenium, hirta cichoracearum

I. nervosa aurica.

I. Oculus-Christi, salicina cichoracearum,

*I. salicina yo dcm
*]satis tinctoria

Ds *fentescens. *xanthifoliiigios uet ec ee E. cichoracearum.

Johrenia sp E. polygoni
*Juglans P. corylea

J. cinerea, nigra M. alni.

Kuhnia énpatorioides E eichoracen,

Laburnum vulgare enter Me UE. M. nii.

DUDEN DICVEOSUNE, * ordain. ooo uus RR S. man var. fuliginea.
*L. muralis E. cichoracearu
EE EE EE sys E.

‘*L. pulchella E. cichoracearum.

L. Raddiana S. humuli var. fuliginea.

L. Scariola E. cichoracearum.

L. Sibirica S. humuli var. fuliginea,
*L. viminea esse Gcharae

nn keen E on Australiana,

um album, *amplexicaule, EE *intermedium,
nati pürpureum Reet coste or o PE Lo eas .E. galeopsi

Laportea bulbifer: E. cichoracearum
Bie um — Ge E. cichoracearum.

* S. ** Castagnei.”’

mes d ok *montanus, *Nissolia E. polygoni.
ochroleucus M. alni.

e SN M. diffusa.

*L, palus M. alni.

E pisiformis, *polymorphus, polyphyllus, agree rn

E praten

L. lea uliginosus, venosus E ple €

L. venosus
T "n1

S. humuli var. ae

E. galeopsidis

274 A MonoGRAPH OF THE ERYSIPHACEAE

Lespedeza capitata, hirta, striata M. diffusa.
*L. striata E. polygoni
L. violacea. M. diffusa
igustrum medium M. alni
ne genistifolia E. polygoni.
garis S. ** Castagnei,’’
Liriodendron Tulipifera P. corylea and
E. polygon
Lithospermum arvense E. cichoracearum.
* Mi DÉI g i
L. officinale E cichoracearam.
*Lolium perenne à E. gramin
Lonicera alpigena M. alni var E
erulea alni var. divaricata.
L. Caprifolium M. alni var. lonicerae.
"n P. corylea.
. flava M.alni and var.lonicerae.
L. glauca, glaucescens, *hirsuta M. alni.
L. *hispida, implexa M. alni var. lonicerae.
L. involucrata 1. alni
L. lutea, nigra M. alni var. lonicerae.
L. ig cts, sehe M. alni.
L. Peri M. alni var. lonicerae.
L.: sempervirens, WEEN M. alni.
L. tatarica, Xylosteum M. alni var. lonicerae.
L. Xylosteum P. corylea.
phanthus anisatus S. humuli var. fuliginea.
Lotus Resin ora *major, Purshiana E. polygoni.

*TLunaria redivi

Lupinus SCH =... *argenteus, var. see

laxiflorus, luteus, parviflorus, eme sericeus,
Lychnis ie pom Degen e
Lycium barbarum, Europaeum, eer E EE M. Mougeotii.
jy 5 tu L. ** Castagnei.’’
*L. Ruthenicum ........ ougeotii.
Lycodesmia juncea E. cichoracearu
*Lycopersi t E. polygoni
Lycopsis arvensis :
ER. x. E. cichoracearum.
Lycopus s a ey
*Lyonia paniculata .. M. alni and var, vaccinii,
Lygodesmia junc: E. cichoracearum.
Lyt Salicaria E. polygoni.
Madia glomerata E. cichorac
Magnolia *acuminata, groer, Kobus ... P. corylea.
*Malcomia maritima . E. polygoni.
Marrubium vulgare ................. E. galeopsidis.
Medicago falcata, lupulina, sativa E lies

Melampyrum nemorosum, pratense, sylvaticum..................S. humuli var, fuliginea.

Host—INDEXx 275

Melilotus alba, officinalis oo

Meni spermum Canadense i M

Mentha aquatica, arvensis.......... eee nnnm rmn E. bei ues
Mercurialis perennis ............ eee nnn Se P. co

Merten ngia maritima, Gesten E E. cichoracearum.
Micr h S. humuli var. fuliginea.
*Mikania scandens E. cichoracearum.
* Milium effusum E. gr

*Mimulus luteus.................- eee E. cichoracearu

Persica S. humuli
Morus alba P. corylea
rubra U. geniculata

Myosotis *intermedia, *sparsiflora, *sylvatica E. cichoracearum.
Myrrhis odo E. pol i
Napaea dioica E. cichoracearum.
*Negundo aceroides P. corylea
Neillia opulifolia S. humuli
Nemopanthus fascicularis alni

Ne epeta podostachys E. tau

Nicotiana Tabacum E. cichoracearum.
Nyssa iem P. corylea.
Odontosp um aquaticum E. taurica.

OEn Beds Verger biennis, *sinuata E. polygoni.
*Olea Europaea P. corylea
*Onobrychis viciaefolia E. polygoni

Ononis arvensis, *hircina, repens, spinosa
anthit

*Onopordon Acanthium E. cichoracearum.
1 lici 5 D

*Onosma p
Orobus lathyroides E. polygoni.
Ostrya Virginica : U. macrospora, M. alni
and P. corylea.
Oxalis corniculata, var. stricta, Suksdorfii, *violacea . ........ x Russellii.
Oxytropis Lamberti E. polygoni.
Paeonia obovata, officinalis, peregrina......... ..-. eene =
Paliurus aculeatus. ... P. corylea.
anicum sanguinale E inis.
Parietaria *debilis, *officinalis, Pennsylvanica............ ia E. cichoracearum.
Parmentiera alata......... co
ia sroliniana Se E. poly
Paulownia imperialis ...........-«--- P. corylea.
Poller ies N a humuli var. Em.
SP. foliosa. ....,. e rne trc S. ** Castagnei
P. Groenlandica, lanceolata, pycnantha, resupinata,...........5. humuli var. duliginen;
E EE E. polygoni.
Pevanmh.: Hemala.... ert SE E. taurica,
*Pentstemon barbatus........en eee . ** Castagnei.”’
Peucedanum *Alsaticum, RE, Orcosclinum, sa lieu
erebinthaceum...........- n it ea bei pense qiie sili polygoni.
celi E. cichoracearum.

a circinata, Monitii c

276 A MONOGRAPH OF THE ERYSIPHACEAE

E polygoni.

*Phaseolus helvolus
is

Teo) Lewisii

gie eum
Phloiodocarpus Dahuricus
Ph

hlomis ne venti
LE

P. tuberosa
* fad

E. cichoracearum

Phlox divaricata
* DÉI cr

S. humuli var. fuliginea.
E irharacearım i

*P. Drummondii

S. humuli

E. cichoracearum

a
ce Alkekengi

humuli var. ER

deca mum commutatum

crasma RER

.E. polygoni.
M. alni

E. taurica.

Zeie RER a
Lem: “

*Pilea pumila

polygoni.
E. cichoracearum.

P. stipulosa
Lu

E. polygoni.
et

Pimpinella magna, Saxifraga
Pis 1

m sativum

Plantago Bellardi, *Coronopus, Kamtschatica, Lagopus, lan-
l

ceolata

E. cichoracearum.

P. lanceolata

S. humuli var. fuliginea.

E. cichoracearum.

er major, and var. Asiatica
oe

P. maritima, media

S. ** Castagnei."'
E. cichorac

media

xp, Psyllium

earum,
S. humuli var. fuliginea.
E. cichoracearum.

cmq Occidenta'is

M. alni.

S. ** Castagnei.”’

Poa annua, pena bulbosa, nemoralis, pratensis,

inaica, tenuifolia, trivialis

serotina, graminis.
Polygonum iiie, dumetorum, EN *Persicaria,
issimum and var. *prolificu E. polygoni.
Populus alba, *angustifo balsaniife and var, candicans,
ciliata, ag entata, p sva monilifera, nigra,
pyrami tremula, tremuloides, trichocarpa. ............... U. salicis.
*Potentilla wi: E. polygoni.
P. Anseri S. humuli.
*P, approximata S = Castagnei ep
P. bifurca S. humuli.
* DÉI n

A Ee fragarioides, pn. palustris .................5. humuli.

Le Castagnei. 2

Host-Inpex

277

E reptans, Tormentilla

*P. viscosa

cichoracearum

S. humuli.
E

Poterium Canadense and var. medium, officinale, and var. car-

neum

S. humul

*P. Sanguisorba

*Prenanthes alba
* €& DÉI

*

: i.
S. ** Castagnei.’’
S. humuli

P. Sitchense (cult.), tenuifolium and var. album
lb

cichoracearum

S. humuli var. fuliginea.
E. cich

P. *al tissima, purpurea

t

S. humuli var, fuliginea.
E. cichoracearum

P. purpurea
=. L3
m

E ygoni.

Prunella vulgaris
* “ec “

S. humuli var. pr ca
E. cichoracearum

Prunus Americana
* DÉI Ce

P isse
corylea.

P. Armeniaca

ry
P. oxyacanthae var,

tridac

P. Avium

*

P Eiere ka
P. corylea

P. Besseyi

P. oxyacanthae

P. Cerasus

ea and P. oxya-

*P. Chicasa

canthae
P. oxyacanthae

P. communis

P. oxyacanthae var.

P. demissa, domestica

P. domestica, insititia.....

P. insititia

*P. Mahaleb

P. Padus

*P Pennsvlvanica
= J

*

*

*

P. Persica
[77

E en

P. pumila

P. serotina

D

P spinosa

dact. sis and U. poo

P. Virginiana P. nd
Psoralea drupacea E. taurica.

P. tenuiflora E. polygoni

Pulmonaria mollis, officinalis E. cichoracearum.
rus laliformi P. corylea.

P. Aria : S. humuli.

P. Au cuparia

P. oxyacanthae var. tri-
actyla.

278 A MONOGRAPH OF THE ERYSIPHACEAE

P. communis

P. *coronaria, Cydonia, Germanica

A, f
P. Germanica

P. corylea.

P. oxyacanthae.
orylea

corylea.
P. leucotricha and

P. Malus

oxyacanthae,
P. Sieboldi P. leucotricha.
*P. torminalis P. corylea.

Quercus agrifolia

S. lanestris and E. trina.

QO. alba

M. alni and var. extensa-

Cc

*

S. lanestris.

M. alni and var. calocla.

G. aquatica

Q. ges and X macrocarpa, and X Michauxii, Catesbaei. an alni.
Q.C

tesbaei, *coccifera

dophora and P. corylea.

P. corylea.

Q. coccinea and var. tinctoria

(9. Peur dentata

M. alni and P. corylea.
M. alni

Q. disc

P. corylea and M. alni

var, extens
C falenta un edis M. alni and n corylea.
Q. glauca polygoni
Q. Ilex P. corylea.
*Q. ilicifolia M. alni or var. extensa
imbricaria M. alni

M. alni var. caloclado-

E
Q: latirifolia

- phora
M. alni.

Q. lyrata, macrocarpa
Q. macrocarpa

S. lanestris and P. cory-

*Q. minor

S. lanestris

Q. nigra

M. alni Ss vars. ex

and calo en
and P. corylea.
alni.

Q. obtusiloba
lustris

M. alni var. extensa and

P. corylea

Q. Phellos M Kee

y P. corylea.
Q. Prinus M. alni and S. lanestris.
Q. Robur P. corylea and M. alni
Q. rubra M. alni and var. extensa

a and P. corylea

à | S. lanestri
. Ranuncu olius, acris, arvensis, *Asiati-

us abortivus, *aconitif
cus, ores Cymbalaria, Flammula,* lanuginosus, *Lin-
gua, *macranthus, montanus, multifidus, Pennsylvanicus,
peu, sardous, *sceleratus, *septentrionalis, trachyc

car-

Md. alpina.

E. polygoni.

» P. corylea.

Host—INDEx 279

R, cathartica M. alni
» " M. alni var. divaricata
R. Frangula M. alni var. divaricata.
Ebonodhas *angustifolius, *minor S. ** Castagnei.”’
Rhododendron sp P. corylea.
R. nudiflorum í M. alni. -
Rhus copallina, glabra, *typhina S. humuli.
Ribes paon Cynosbati S. mors-uvae.
R. Cynosbat P. corylea.
R. doen var. irriguum, Floridanum S. mors-uvae.
R. floridum S. humuli.
7 M. grossulariae
R. *gracile, Grossularia S. mors-uvae.
R. Grossularia Y M. grossulariae and
P. corylea
R. Hudsonianum, lacustre S. mors-uvae.
R. P. corylea.
R. Missouriense S. mors-uvae.
HR. TE M. grossulariae.
R. prostratum, rotundifolium S. mors-uvae.
*R. rotundifolium M. grossulariae.
R. rubrum S. mors-uvae. -
R. sanguineum M. grossulariae.
Robinia *Pseudacacia, viscosa . E. polygoni
Rosa alba S. pannosa
R. Arkansana S. humuli.
arvensis S. pannosa
R. blanda S. bh li
R. canina, centifolia, *cinnamomea, damascena, *dumetorum,
Doemer Gallica, *glauca S. pannosa.
R. lucida S. humuli
R. pomifera, *rubiginosa, tomentosa, villosa S. pannosa.
Woodsii S. humuli.
bus Canadensis E
*R. er fruticosus ”’ P. corylea.
R. hispidus, SR p *strigosus, triflorus.........S. humuli.
Rudbeckia hirta, *occiden E. cichoracearum.
Rume lla E. polygoni.
m T E.
*R. Hydrolapath E. polygoni
*Saccherum officinarum .E. i
Salix Weeer eech F. Sector
S, alba BR EN e salic
KU e ee eh Schlechtendai
S. *angustifolia, Mia, Caprea and var. padula Ee Us sali
EC nenne .P. corylea.
S. spin cordata, daphnoides, discolor, gege and var
Scouleriana, *fragilis, *glauca, humilis, *incana, livida,

"api nigra and var. fdicata, nigricans, petio tiolaris

280 A MONOGRAPH OF THE ERYSIPHACEAE

purpurea, *pyrolaefolia, repens, sericea, Seringiana,

triandra, Urbaniana, viminalis U. salici

S. viminalis t Be,
*Salsola canescens E. taurica.
*Salvia glutino E. cich
*S. verticillata . E. galeopsidis.
Sambucus Canadensis s M. grossulariae.
" ee i.
*S. nigra Peo

S. racemosa and var. pubescens M. grossularia
Sanvitalia erpa S. humuli var. fuliginea.
*Saussurea E. taurica

S, ais d E. eich

axifraga cortusaefolia E. polyg
*S. punctata . S. ** Casta

S. rotundifolia

S pnm var. SCH
Scabiosa arvensis
éé [21

See E. SER,

. Caucasica...... S. humuli.
*S. integrifolia S. ‘* Castagnei.’’
S. *stellata, *succisa, sylvatica. E. polygoni.
Scandix P. ris a
Schizandra Chinensis..................... M. alni.
DOO MU elei mere T e S. ** Castagnei,’’
S. *hirsuta, Hispanica, humilis , E. cichoracearum
S. radians S. * Castagnei.”’
phularia canina.... S. humuli var. fuliginea.
PREMIER ne EE E. cichoracearum, U. Co-
lumbian
* zb ipe E. galeopsidis
* DÉI HI lygo
S. multicaulis, E. taurica.
*S. terre E. galeopsidis
S. scordiifolia. E. polygoni
*Secale cereale............ E. graminis.
linum carvifolium E. polygoni,
Senecio ge cordatus, Fuchsii.. S. humulifvar. fuliginea,
. hydrophilus.. ..... .E cicero
"S. ka Xem * S. ** Castagnei.
S. Ingens......... Mete * .... S. humuli var. e
"S. on Zi -..S. Castagn
eene S. humuli var. "fuligine.
*S. "bibo See Seene een, ** Castagnei.’’
e SE SCENE S. humuli var. fuliginea.
S. sylvaticus : i s.e... E. cichorac
ll, = ** Castagnei.’’
S. triangularis............... ER. eg var. fuliginea.

tasses H cr SENAAT

Host-Inpex

281

nre E. cichoracearum.
Seseli T hanti E. polygoni.
*Sesleria caerulea E. graminis.
Shepherdia argentea, Canadensis S. humuli.
Siegesbeckia orientalis S. humuli var. fuliginea.
XQ: a E po olyg

*Silene noctiflora

*Siler trilobum bid
Silphium terebinthi E. cichoracearum.
Sisymbrium *Alliaria, *officinale, Sophia E. polygoni
Sium erectum, *latifolium E. polygoni.
myrnium Olus atrum 6
Solanum Carolinense....... E. cichoracearum.
Solidago iun nes *Missouriensis, nana, *occidentalis,
*ri gida, serotina cichoracearum,
Sonchus arvensis ër
* ze [23 polygoni.
S. asper, oleraceus E. cichoracearum.
*Sp tium junceum E polygoni
Se Aussen id
S. betulifolia P BEE
S. Camtschatica S. humuli
*S, discolor ee P. oxyacanthae
S. Douglasii P. oxyacanthae
var. tridactyla.
Kach Filipendula S. ** Castagnei.’’
S. salicifolia P. oxyacanthae.
* Thunbergii S. humuli.
S. tomentosa P. oxyacanthae.
S. Ulmaria E. polygoni and
S. humuli

Stachys alpina, aspera and vars. *glabra and Japonica, ciliata
var. pubens, *cordata, Germanica, melissaefolia, palus-

tris E. galeopsidis.
*S. palustris ... E. cichoracearum.
S. sylvatica E. g eopsi is.
Statice Gmelini, Limonium E. polygoni
Stevia sp E. cichoracearum.
Symphoricarpos occidentalis, orbiculatus, racemosus and var.
*pauciflorus M. diffusa.
sco coge officinale E. cichoracearum.
F ;
S. tuberosum E. cichoracearum.
Syringa Amurensis var. Japonica, *Persica, vulgaris........ .... M. alni.
*S. vulgari M. alni var. lonicerae.
= T j P. co

'Tanacetum vulgare

E. taurica.

Taraxacum montanum

rylea.
E. cichoracearum and
P. cory

282 MONOGRAPH OF THE

ERYSIPHACEAE

T. officinale
* ee

S. humuli var. fuliginea.

E. cichoracearum
alni

Tecoma radicans
* DÉI [73

ni.
E. cichoracearu

Tellima grandiflora

Teucrium Canadense

S. humuli var. Kia.
E. galeopsidis.

Chamaedrys

E Sieste

E taurica
E a

* DÉI

Thalictrum al pinum

E, polygoni,
S. humuli var, fuliginea.

Y. Pid), aquilegiifolium, Cornuti, flavum, minus

and var. elatum, simplex

RE ee

E. polygo

*Thelesperma filifolium

So sd tela
[23

Thermopsis montan

Thesium *bavarum, d

.E. polygoni.
M ce

*Thevenotia ae

E. taurica.
E

*Thlaspi arvense
Thymelaea sp

Tilia Americana

*Tragopogon sp

T. porrifolius, pratensis

E. polygo

cichoracearum

*Trifolium sp

T. *agrarium,

S. ** Castagnei.’’

pestre, arvense, filiforme, hybridum, incarna-

tum, ene longipes, Lupinaster, medium, *minus,

anthum, montanum, moranthum
Zem procumbens, *repens, rubens

pauciflorum, pra-

E 08 A

*Trigonella sp ra

T. Cretica, Foenu E leere

Triticum sad ivum, Spelta, vulgare E. graminis

Trollius Europaeus E. polygoni

Troximon glaucum, *officinalis S. humuli var. fuliginea.
*Typha latifolia P. corylea

Ulmus alata

U. Americana

U. macrospora and P.

U. campestris

corylea
M Wegen, P. cory-
lea, and M. alni,

U. fulva

U REN and P-
cory

U. montana

U. macro

spora.
U. clandestina and P.
cory

*Urtica sp S. ** Castagnei.’’
U. cannabina, tes *urens E. polygoni.
Vaccinium M. alni var. vaccinii.
V. corymbosum alni.
V. *intermedium, Myrtillus P. oxyacanthae.

V. Myrtillus vars. macrophyllum and *microphyllum, Penn-
anicum

sylv

M. alni var. vaccinii.

Host-Inpex 283

V. stamineum P. corylea.
V. uliginosum P. oxyacanthae.
V. vacillans M. alni var. vaccinii.
*Valeriana capitata E. polygoni.
V. officinalis E. cichoracearum.
e E. polygoni.
Valerianella *dentata, *rimosa E. polygoni.
Verbascum Blattaria E. taurica.
V. nigrum E. cichoracearum.
v. phlomoides E. taurica.
i E. polygoni.
* “ *pul lent E. cichoracearum.
V. spec E. taurica.
e Le *Thapsus E. cichoracearum.
*V. Thapsus E po ygoni
rbena sp ..S. humuli var. fuliginea.
V. angustifolia, Aubletia, *bracteata, hastata nenn E. cichoracearum
V. hybrida M. ferruginea
V. laevis, *officinalis, stricta, urticifolia E. cichoracearum,
*V, urticifolia E. galeopsidis.
* E i
Meis *encelioides, *occidentalis E. cichoracearum.
ee

Vernon i Pantai, fasciculata, Noveboracensis ..
V RT

Se
S. humuli var. fuliginea.
ae kr

Veronica longifolia, spicata
* crium

E. polyg
V. Virginica S ech var. fuliginea.
Viburnum acerifolium, dentatum, Lantana, Lentago, Opulus,
prunifolium, pubescens, *Tinus alni.
*Vicia sp M. diffusa
V, Americana and var. linearis M. alni and var. ludens.
*Americana and var. *ludens E. polyg
V, Americana var. truncata M a var. degen
V. cassubica M. Baumleri.
V. *cassubica, Cracca, *Faba, *gemella, *hirsuta, oroboides,
pallida, *sativa, sepium, sylvatica polygoni.
V. sylvatica M. Baumleri.
V. tenuifolia E. taurica.
V. unijuga ...... E. polygoni.
*Vincetoxicum officinale 1

Viola se canina var. sylvestris S. humuli.
S. humuli var. fuliginea.

went ht

V. cucullat
Vitis Sege, *Californica, *cordifolia, flexuosa, hederacea,
a

d var, Catawba necator.
*V. Labrusca ........». een nr HI P. corylea.
x M tate See vinifera ..... EE U. necator.
*V. vinifera .... S. rr Castagnei.”’
Xanthium Canadense ...........-- ; S. humuli var. fuliginea

and E. cichoracearum.

ylum EIER
Zelkova acumitats

ERRATA.

Page 8, line 21, for ** a basal,” read re an apical.’

Page 8, line 22, for ** in the first place,’’ read ** SN uently,

Page 8, line 7 from bottom, insert comma after ** shape,’’ and for ** occurs ’’ read
** occur,"

Page Io, line 6, insert comma after “ M hes Praia

Page 23, lines 17, 18, for ** Coumbiana”’ read * Columbiana.’

Page line 5, insert comma after ‘‘interest’’; line 18, insert comma after
“ notes,” and delete comma at e id of line; line 25, for Goen "re or Ottis”
line 36, for “ Prof. A. Macacsy Diete” read “ Prof. A . Magacsy Diet

esii Ge * Th 12, for ** pentcellata’’ read GA line 16, for
** Fen

age 32, line 31, SCH comma after ** species.’
Page 33, line 20, insert comma after ** distinct," and ‘of’? after ze iram E
Page 34, line 2 from bottom, for ** Beier read ** peritheciis.’
Page 36, line 18, for “ Win." read “Wint.” ; line 22, for **Ouden." read

Lë

Page 50, line 8 from bottom, insert ** Sacc.” — x Pueri Fung."

Page 52, line 9, for ** Hortm." read ** Hartm

Page 53, line 3, for ** Cacatiastrum "7 read “ Fits strum.

Page 54, line 8, read comma after ** species"' ; line 9 from bottom, delete comma
after ‘“ measure ’’ ; line k hee: bottom, insert comma after “ indicated," and carry
io to end o

Page 55, line 2, Pe E Ge read **]

Page 56, line 14, for “ fulginea’’ read “fuliginea ” ; line 10 from bottom, for
to” rend. '* of. ^
Page 57, line 12 from bottom, for **aber'' read **über" and for “art” read

9?

Page 61, line - for ** Verwandlschaft"" read ** Verwandtschaft’’; line 7 from
bottom, for ** Auschauung’’ read ** Anschauung "' ; line 5 from bottom, for “ auftren 77

Page 62, line 3, for **shown on a house plant" Wee **sown on a host-plant"' ;

Page 63, line 18, for ** imperfect” read ** infected.

Page 68, line CN for ** weil” read ** weit” ; line 15, for ** nich ” read “ nicht” ;
line 21, insert ** from ” after ** suffer."

Page 71, line Ge from bottom, for ** Treub. "read ** Trent."

Page 79, line 15 from bottom, for ** mere read ** eine "

Page 84, line 18 from bottom, for **on U. gend m gr ele

Page 87, line 13, for ** Oestergren ” read ** Vestergren.

Page 95, line 4 from bottom, for ** ef da a “Enr”

Page 97, line 15, for ** Le" read ‘

( 285 )

286 A MoNOGRAPH OF THE ERYSIPHACEAE

Page 103, line 25, for ** probably " read ** possibly.’

Page 103, line 28, for ** attached ” read ze attacked."

Page 103, line 3o, delete comma at end of line

Page 103, line 31, for ** or" read “of.”

Page 108, line 20, for ** or" read “on.”

Page 109, line 13, for “ forms’’ read “ form."

Page 109, line 25, for ** perisistent”’ read ** persistent."

Page 117, line 1, delete comma after ‘‘Uzcinuda’’ and insert comma after “ pri-

Page 117, line 18, for “ grisecenti ” read ‘‘ grisescenti. e

Page 121, line 3 from bottom, for “Æ. communis’? read SE polygont.”’
Page 122, line 4, insert ** examined” after ze vm ens.’

Page 127, line 23, for ze & " read ** G."
Page 128, line 24, insert ‘‘to’’ after “ related.”
Page 135, line 8, replace semicolon after **Microsphaera’’ by comma.
Page 136, line 12 from bottom, for ** indefinite" read ve in definite."
Page 138, line 3 from bottom, for “fairly " teg We M iy."
Page 139, line 10, insert ** form ” after **an
Page 141, line 4, after * species" read ee e pum of the plant."
Page 141, line 11, for “ tips fill” read * tip fills.
Page 143, line 4 from bottom, for ee Weerl " E ** Neerl.”’
Page 148, line 6, for ** exclusa” read ** extensa.
Page 148, line 11, insert comma after ** a/ni.”
Page 150, line 10 from bottom, for ** E." read « p."
Page 152, line 14, delete comma after ** diameter.”
Page 153, after line 8, insert s ymy and description of var. KEE
(Atkins. ) given at page 153, last three incs, and page 154, lines 1
age 158, line 9, delete comma after ** half.”

Page 162, lines 29-30, for “ necessay "' read omnea
Page 164, last line, for zs lips’’ read ** tips.’

Page 166, line 10, for ** sightly " mead “ slightly."
Page 168, line 9 from bottom, for /* 3-2" read "4-6."

, Page 170, line 5, for ze cored `" read ** seit ’’; line 7, for ** aufangs ” read ** anfangs’’;
line 17, for “un” read “im”; line 18, bad *‘weinger ’’ read ** weniger ’’; line 20,
for, “P. Bäumleri” read “M. ‘Baum leri

Page 171, line 6 from bottom, for tis ” read “ist
Page "5 line 8, for ve Mäumleri” and abo cit ” read rr Bäumleri” and
** Marchica
179, line Cie ior ` giyerpřyllosus? ' read “ glycyphyllos”; line 24, for
** yezoeüsis’’ read ** ezoensis."
Page 180, line mg for ** Nessolia’’ read CM és
Page 181, line 7, for ze Ssevie”’ read ** Seseli.’

^
n

ERRATA 287

Page 187, line 3, for ** of’’ read ** on "; line 5, delete comma after ** vernalis.”

Page 192, line 21, insert ** which" after ‘spores.’

Page 195, line 7, for **knantiae " read ** knautiae.’’

Page 204, line 10 from bottom, for ** Passinini " read ** Passerini.”

Page 215, last line, for ** Erisyphe" read “Erysiphe.”

Page 217, line 5, for rr Carinthe” read ** Cerinthe’’; line 8, for ** Dorycinum
read ** Doryenium.’’

Page 225, line 7, for ** orbiculatus' read ** orbicularis.”

Page 233, line 2, insert “the” before ‘‘Phyl/actinia.’’

Page 234, line 6 from eem, — comma after ** outgrowths,”’

Page 235, line 5, delete ** again.’

Page 236, line 15, for ** soul"' read ** sont’’; line 7 from bottom, insert period
after “A”

Page 237, line Ih for ** radiens’’ read ** radians’’; line 7 from bottom for
“dout” read ** dont.’

Page 244, no. 77, for ** Calmeiro " read ** Colmeiro.”

246, no. 106, for ** Hayl’’ read “ Hem ; no. III, for rr Mycelogensi’’

read ‘‘ Mycetogenesi"' ; no. 125, delete “ Part 3.’

Page 248, no. 160, for rr Sphraco-’’ read rr Sphaero-.’?

Page 250, last line, for ** 1858,” read ** 1851."

Page 251, no. 222, for ** 17—,’’ read “ ee

Page 252, no. 237, for ** Malphigia’’ read ** Malpighia.’’

Page 256, no. 321, for ** Shumacher ” deeg e geären "

Page 258, no. ve "ei ** Nauv." read “ Nouv.’

Page 259, no. 384, for ** Wetteranisch.’’ read ** Wetterauisch.”’

Page 262, line 11 from bottom, for ** hausterium’ aee ** haustorium.

Page 264, line I, for ** oplhantha "7 gg EH freiem

Page 266, line 20, for ** corleay ” read *

Page 272, last line, insert ** see page Md.

3?

AVote.— The numbers occurring in the geographical bulbos and following cer-
tain host- e ia to € records, which will be found in the works of au-
thors quoted under the respective number in the Bibliography; in all other cases, the
occurrence of the ava on the host-plants given, and its geographical distribution,
have been personally verified.

INDEX.

(Synonyms in Roman ; adopted specific and varietal names in Italics. )

Albigo calendulae, 51 signis on — 195
drabae, 51 dearum, 4
epilobii, 47 var. ale 46
fugax, 47 humuli

uli, hyperici, is 4
lanestris, 74 labiatarum,
leucotricha, 40 lamprocarpa, 20

ors-uvae r. balsami
Niesslii, 47 ar. labiatarum, 205
nnosa, 66 o begs 195
phytoptophila, 76 gees, 225
pruinosa, 4 macularis, 46
Sammer 71 nitida, 175
Alphitomorpha adunca var. amentacearum, een 81
I
var. populi, 81 pistes 129
var. prunastri, 95 b , e
r. rosacearum, 95 P En
var. ul: 97 var. caprılo Mio, $67 143
aln ^ v n grossulariae
anhani rhamni cahita, 129
artemisiae, 194 Less, ` 75
astragalı, 127 populi, 81
ballotae, 205 > prunastri, 95
bardanae, 194 rosarum, 236
erus, 9o M nr
ortilis, 213
acl, 36
ee var. KE 46 mium, 174
var. oxya urticae, 17
comata, 125 Botrytis euphorbiae, 71
communis, 174, 195
var. cichoracearum, 194 en rat
ar. graminearum, 209 ën E34,
var. labiatarum, 20 ze li 14
var. nata o :
corni, 213 vus ee: 143
: riesii
cynoglossi, 194 N
grossulariae, 15
depressa, ro He gii, I 30
var. lonicerae, 142 holosericea, 127
epigaca, 237 » penicillata, 130
erase pet | Dematium Erysiphe, 224
euonymi, 125 ses 237
a, 46 acariforme, 237
aceris, 90, 93
adunca, 81
. amentacearum, 81
var. populi, 81
. prunastri, 95

INDEX 289 ©

Erysibe adunca, var. ulmorum, 97
alchemillae, 46
alni, 225
andraeacearum, 238
nis, 46

1 S, 90
biscia 194
Br a,

circumfusa, 50, 194
clandestina, 30

mata, I2 `
communis, 50, 175, 194, 210
var. cichoracearum, 194

ci
ar, graminu
var. labiatarum, 205
rina sre 75
ryli, 225
depres, 194, 2 15
r. artemisiae, 194
div Re 23, 146
var. 23
var. frangulae, 146
var. onicerae, 143
epilob

epimiche, 175
ferruginea, 46
ec e "46, 50
SS 205
minis, 210

lamprocarpa, I95, 205
balsaminae, 50

ar. - galeopsidis 205

arum, 205

pisi, 17

Erysibe polygoni, 175
uli, 81

ulmariae, 176

ERYSIPHE, f 73

m
agregata, 221
6
al cile. 46
alhagi, 216

cerasi,
chelones, 205

cichoracearum, 191, 193

clandestina, 30, 97

comata, I2

communis, 46, 50, 127, 175, 194, 205,

var. cichoracearum, I95
raminis, 209

dipsacearum,
divaricata, rg 146

290 A MONOGRAPH OF THE ERYSIPHACEAE

pe ghi var. frangulae, 146 mne. erer ne var. euonymi, 125
157

r. lonicerae, 143 ossular
doronici, 50 nig arene d
aei, 216 rhamni- ME 146
veda cadens, 50 Pone. f 176
x erodii, 46 phlogis, 195
euonymi, 125 picridis, 215
euphorbiae, 164 pisi, 174
fagi, 225 Deg in
ginea, 46 polychaet
fraxini, 224 polygoni, L3 E 197
fuliginea, 46, 50
fungicola, 238 e St, Ce
SC Ze? peterii, 46
... 95
een 197, 204 pyri, 225
gerardiae, 50 quercinum, 130
gigantasca, 7I quercu:
glomerata, 46 quisquiliarum, 205
raminis, 2 radi 2
grossulariae, 157 anunculi, 175, 176
guttata, 225 robi
mespili, 226 roboris, 225
heraclei, salicis,
olosericea, 127 rc aeri 45
h la, I9 saxaouli,
var. cynoglossi, 196 Sieger? E 237
muli, 45 scandens, 239
ilicis ees scandicis, 174
knautiae 195 scorzonerae, 195
abia s 3 P
lamprocarpa, 1 195, 205 spadicea, 196
galeopsidis, 205 syringae, 130
var. plantains, 50, 196 taurica, 197, 215
lanata, | tiliae, 237
| t tosa, 7I

umbeiiferarum, 176
vaccin ar
va ans,

T E 20s dre 194, 224
suffultum,

| Erysiphella aggregata, 221
Carestiana, 226
trina, 223
Erysiphopsis parnassiae, 177
Eurotium rosarum, 65
Meliola (Meliopsis) calendulae, 51

apr ian cry 121
Gei Ee
dnt, dd
var. € alocladaphors isga
6

ubyl, I

viburni, 131
Mucor Erysiphe, 45, 90, 93, 174, 193, 204
Oidium, 26

INDEX

Oidium iat 93

baleamii, 190, IgI
Pen
leucoconium, 67
monilioides, 213
tabaci, 204
Tuckeri, 101--104
ventricosum,

Perisporium erysiphoides, 175
PHYLLACTINIA, 224
antarctica, 226
berberidi

ata, 226
Schweinitzi," 237
suffu

var. macrospora, 226
Pleochaeta Curtisii, 113, 115 —

biuncinata, 39

tagnei,
zeen Së
amulicola, 30
6

Sclerotium Erysiphe, 45, 174, 224
. corylea, 224
var. herbarum, 174
suffultum, 224
Sphaeria myrtillina, 30

— n

epilobii, 47

291

292

gax, 47

Ni

pannosa, 65

phytoptophila, 76
"uinosa, 47

tomentosa, 71
UNCINULA, 79

aceris, 90
var. Tulasnei, 93
|. .. adunca, 81

Sphaerotheca erigerontis, 51

A MONOGRAPH OF THE ERYSIPHACEAE

Uncinula clandestina, 97, 98
intonit, I

Clin
Col i 2
con

geniculata, 111
heliciformis, 81
intermedia, I
luculenta, 81
Lynchii, 113
macrospora, 107
necator, 99
parvula, 106
polychaeta, 113, 115
astri 95, 96