68 
Mycologia 
viscosa, from New Holland.” At the risk of appearing to be 
trite we may remark in passing that not only has there been 
advances made in mycology, but in other fields of botany as well 
in the past third of a century. Moreover some geographic names 
have also changed. New Holland is one of these, being labeled 
on our maps to-day New Guinea. As to the hosts in question 
both genera appear among the Scrophulariaceae in De Candole’s 
Prodromus while in Engler and Prantl’s Pflanzenfamilien they 
both appear under Solanaceae. In other words De Bary’s 
taxonomy and geography were correct in his own day. This same 
reference to scrophulariaceous hosts is quoted by Lindau 2 and is 
given hy Clinton as a reason for suspecting the validity of P. 
Thalictri. 
Various theories have been advanced as to the means by which 
the present species maintains itself from year to year, one of them 
being that the fungus lives over in the soil or in the diseased 
tubers and debris from the crop. A paper by Stewart (1913I 
details some experiments on this question. Soil was taken from 
a field which had produced a crop of blighted potatoes. Diseased 
and partially decayed tubers and blighted stems were placed in the 
soil which was subsequently kept outdoors until spring, when it 
was planted with tubers procured from a blight-free field and 
treated with disinfectants. No infection occurred, nor could it be 
induced by painting the leaves with mud prepared from this soil 
and the diseased potatoes. The author considers his results in- 
conclusive, but indicating that it is highly improbable that the 
disease persists in the soil over winter. 
7. Phytophthora Thalictri Wilson & Davis 
The oospores of this species were found by Clinton (1909: 894) 
who says that “ so far as could be determined, the antheridia and 
oogonia were developed from dififerent mycelial threads.” In the 
light of present knowledge this would indicate that these organs 
are of the same nature as those of P. infestans. The oogonia are 
reddish-brown, a little deeper tinted than those of P. Phaseoli, 
moderately thin walled, and measuring 25-33 /* diameter. The 
oospores are hyaline or very light colored, with medium thick, 
2 Sorauer. Pflanzenhr. ed III. 2: 140. 1908. 
