172 BOTANICAL GAZETTE [MARCH 
show the success it has attained. Many of the appressoria of 
this species agree with De Bary’s haustoria appendiculata. Fig. 19, 
being a side view, shows only one outline of the organ of attach- 
ment. Long infested blades of Poa show signs of injury from 
the fungus. “In California it has been destructive to wheat” 
(13).5 Certainly these haustoria give the impression of activity 
not gained from other Erysiphez. 
The habit or structure of the other species of Erysiphe stud- 
ied do not differ so much from the account given of £. communis 
that a detailed description is necessary. Basal (and even higher) 
cells of hairs are especially favorable places for the study of 
haustoria. Fig. 76 represents such a cell from a hair of Eupator- 
tum perfoliatum infested by Erysiphe Cichoracearum. The nucleus 
of the cell lies between two of the haustoria and seems to be dis- 
organized. The cell is slightly plasmolyzed. The dark globules 
(stained red in the sections) do not seem to be degeneration 
products due to the action of the fungus, for the cells in unin- 
fested leaves contain them. They are probably due to the fix- 
ing reagents. This plant, it is well known, contains a volatile 
oil and aresin. It is probable that the globules are related to 
these substances. It is very common to find such products as 
these in the autumn, when this material was gathered. 
UNCINULA SALICIS. 
Uncinula Salicis on Salix discolor exhibits peculiarities in its 
appressoria and haustoria, which apparently have not been 
reported heretofore. De Bary (12, p. 27) mentioned the lobed 
appressoria (haustoria lobulata) of this species, then called i 
adunca, but he did not report any peculiarities in the haustoria ; 
and Galloway examined U. spiralis (U. necator). It has fre- 
quently been stated by De Bary and others (12; 323 363 205 18 ; 
14, p. 555; 13, p. 2; 19) that the Erysiphee always confine their 
absorbing organs to the epidermal cells of the host. Berkeley ; 
it has been mentioned, believed in the hemi-endophytic habit of 
’The writer has never found it difficult to collect material, with ascospores 
developed, in August and September. 
