208 SALMON : SUPPLEMENTARY 
spores. This is the case, e. g., with the specimens in Rabenh. 
Fung. Eur. 1056 (from Saxony), in which nearly all the asci are 
trisporous, only rarely being bi- or tetrasporous (see p/. 9, f. 14, 
15). This fact is interesting for two reasons. In the first place, 
for the evidence it affords in the question of the specific worth of 
“ P. Candollei Lévy.” (see monograph, p. 230); and, secondly, for 
the parallel it offers to the variation found in Uncinula polychaeta. 
This species of Ucinula in the United States possesses.as a rule 
regularly bisporous asci, only very rarely showing three (or, accord- 
ing to Tracy and Galloway, four) spores in the ascus; in China 
and Japan, however, the asci are usually trisporous, but some- 
times bisporous, or rarely show four or even five spores. In the 
case of U. polychaeta the form which shows an increased number 
of spores in the ascus is more or less definitely connected with a 
certain area in the geographical range of the species, while in P. 
corylea this variation occurs quite independent of locality. 
P. corylea has been described as being sometimes amphigenous ; 
I believe, however, that this is erroneous, and that its mycelium is 
always strictly hypophyllous. The description of the species as 
epiphyllous is probably due to the fact that perithecia attached by 
their penicillate cells occur very commonly on the upper surface 
of leaves, and also to the fact that an epiphyllous species of mildew 
may grow on the same leaf with the Phyl/actinia. In the Kew 
herbarium, ¢. g., there are leaves of a Quercus, from the United 
States, which bear on the under surface the mycelium and peri- 
thecia in all stages of development of P. corylea, while on the upper 
surface there are the mycelium and perithecia of Microsphaera alni, 
and among the mycelium perithecia of P. corylea attached by their 
penicellate cells. . 
Freeman (20) has recorded the occurrence of P. corylea on. 
Tilia sp. from Minnesota, U. S. A., but the author has since 
written to nfe that this record must be expunged, the host-plant 
proving to be probably a species of Cornus. 
Feltgen (18) wrongly refers the name “ Erysiphe stellata ~ ali. 
Marchand to Microsphaera alni. Marchand (49) described hig 
plant as follows: “‘ £. stellata N. Hypophylla, filamentis plurimis, 
tenibus, stellato-expansis. N. 8 coryli N.—Erysiphe corylt Hedw. 
7 alni N.—E alni DC.” The description given, and the synonymy 
quoted, show without doubt that P. cory/ea was intended. 
