197 
an endophytic member of the Erysiphaceae . 
‘ Oidium obductum , Ell. & Lang. /. M intuit , E. & E.. on Mimulus glu- 
tinosus. Berkeley, California. (W. C. Blasdale.)’ On examination, this 
was found to be the conidial stage of a fungus possessing endophytic 
mycelium and branched conidiophores emerging through the stomata of 
the leaf (Figs. 11-13). In these characters it resembled O. taurica in 
its conidial stage, but the conidia of this fungus on Mimulus differed 
at first sight in being thick, uniformly oblong or cylindrical, and usually 
more or less angular in outline. This difference in the shape of the 
conidium, together with the fact that O. taurica has not hitherto been 
reported from America 1 , inclined me at first to the belief that the fungus 
might prove to be a new species of Oidiopsis , endemic to America, and dis- 
tinct from the Old World species. On examining, however, further material 
of O. taurica on its numerous hosts in Europe and Africa, I discovered 
conidia of the same type in three cases, viz. on Daucus maximus from Greece, 
on Chondrilla juncea from Hungary, and on Foenictdum vulgare from Algeria. 
As in these cases perithecia are present, it seems clear that the American 
plant belongs to O. taurica . The plant on Daucus maximus was published 
as a new species under the name of Erysiphe lanuginosa by Fuckel in 1871, 
the specific characters relied upon being certain mycelial and perithecial ones 
which proved, however, not to be distinctive (see 2 , p. 218). In the diagnosis 
given, the conidial stage is thus described : £ Fungo conidiophoro dense 
lanuginoso-tomentoso, candido, late efifuso, caules foliaque tota occupante, 
conidiis oblongo-ovatis, utrinque obtusis,hyalinis, 32 mik. long., 16 mik. crass.’ 
I consider the distinctive shape shown constantly by the conidium 
in all the examples examined on these four host-plants (Mimulus glutinosus, 
Daucus maximus , Chondrilla juncea , and Foeniculum vidgare') of sufficient 
value for the separation of the plant as a variety, and I propose to use the 
name of lanuginosa (Fckl.) in giving the present form varietal rank. 
The occurrence of O. taurica , in the conidial stage only, in a single 
locality in North America is a very surprising fact ; it seems, too, somewhat 
unlikely — -considering the careful attention that has been paid to the Family 
by numerous mycologists in the United States— that the perithecial stage 
occurs frequently, if at all. 
I should like here to draw attention to the curious case of parallel varia- 
tion shown by O . taurica and Phyllactinia corylea. As I have lately pointed 
out ( 5 ), we find a marked variety of P. corylea , distinguished by the shape 
of the conidium, on certain of its host-plants. Now the shape of the 
1 It may be pointed out here that the fungus occurring on Euphorbia sp., in the Argentine 
Republic, lately published by Spegazzini (^14) as E. taurica Lev., var. andina, does not belong 
to E. taurica. As recorded in my Supplementary Notes (3, p. 191 ), this fungus on Euphorbia, 
while much recalling E. taurica in habit, and in the large size of some of the perithecia and their 
asci, clearly belongs to E. Cichoracearum DC. I have lately re-examined the authentic example in 
the Kew Herbarium, and can state that it shows the ectoparasitic mycelium and the conidial 
( Oidium ) stage characteristic of E. Cichoracearum. 
