6 4 
Journal of Agricultural Research 
Vol. V, No. a 
PERONOSPORA FICARIAE 
On May io, 1911, Peronospora ficariae was very prevalent on Ranunculus 
fascicularis in the vicinity of Madison. This fact, coupled with De Bary’s 
(3) statement in connection with his discussion of the perennial nature 
of mycelium of Phytophthora infestans , that Peronospora ficariae is peren¬ 
nial in the tissues of Ranunculus ficaria , led the writer to determine whether 
it survives the winter in the mycelial stage on Ranunculus fascicularis also. 
Eighteen plants, very generally infected with the disease, were staked on 
the date above mentioned so that they could be readily located through¬ 
out the winter and following spring. On February 2, 1912, five of the 
plants were chopped out of the frozen ground and carried into the 
greenhouse, where the adhering soil was allowed to thaw out and was 
removed from the fascicled roots, after which the roots were carefully 
washed until free from soil and then transplanted in greenhouse soil. The 
plants, two of which refused to grow, started very slowly, the first one 
coming up on March 3, and two others the following day. The young 
plants were chlorotic, distorted, and yellowish green, but there was no 
evidence of Peronospora ficariae present until they had been held under 
small bell jars for 24 hours, after which the fungus present on the 
deformed leaves fruited profusely, showing plainly that the fungus was 
alive in the host tissues during the winter. 
The 13 plants that were left in the marked space from which the 5 
were taken were also watched carefully after they began to come up. 
On April 5 five appeared, and these were covered with small bell jars. 
On the following day conidiophores and spores of Peronospora ficariae 
were collected from the underside of the leaves, showing that in this 
case also the plants were infected before they reached the surface of the 
soil. The results of these experiments confirm De Bary’s (3) statement 
and also show that Peronospora ficariae is perennial not only in Ranun¬ 
culus ficaria but also in Ranunculus fascicularis . 
PERONOSPORA VICIAE 
Peronospora viciae occurs on several of the legumes. On May 11, 
1913, the writer found it to be quite abundant on Vicia sepium , a peren¬ 
nial common in the District of Columbia. At that time about 25 per 
cent of the plants, which were from 4 to 6 inches high, were infected with 
the disease, the fungus sporulating profusely and the plants giving every 
evidence of systemic infection. The location of these plants was staked 
off on the date above mentioned and the patch kept under observation. 
On April 5 the following spring the plants started to come up, the tallest 
being only 2 inches, and at this early stage nine were found to be system- 
ically infected. It was not uncommon to find a healthy and a diseased 
plant within 2 inches of each other. If infection was caused by oospores 
or conidia, it is difficult to understand why the infection was not general 
