202 
that this fungus is closely related to the downy mildew of the grape it 
is safe to conclude that an occasional spraying of the vines with either 
the Bordeaux mixture or the ammoniacal solution of copper carbonate 
would prove an effective remedy. The only difficulty will be experienced 
in getting the liquid upon the under surface of the leaves, where it 
should lodge to be of most value. It remains to be seen whether the 
peronospora will attack and damage the water-melon, musk-melon, cit¬ 
ron, and other cucurbitaceous plants related to the pumpkin, squash, 
and cucumber. 
% 
The potato rot ( Pliytophthora infestans , DBy.) has been unusually 
abundant in New Jersey, so much so that many large potato-growers 
have secured only a small fraction of a crop. The exceptional season 
has been a hard blow to the rot-proof theory that some “potato-seed” 
dealers have advanced. As far as observed there has been no one sort 
of potato that failed to be attacked when the conditions of moisture, 
warmth, etc., were most favorable. Apparently healthy potatoes se¬ 
cured from areas where most of the tubers have decayed show the 
threads of the fuugus in the tissue, and especially in that portion in the 
vicinity of the eyes. Many farmers are still to be convinced that there 
is any danger in using such potatoes for the next season’s planting. 
In July some of the vines of Ampelopsis veitcliii , commonly known as 
the Boston ivy, were found infested with a peronospora, that proved 
upon examination to be the P. viticola , DBy., so prevalent upon the cul¬ 
tivated grapes. Only a few plants out of many hundreds that are to be 
found in this vicinity were attacked, and all of these were young vines. 
In no case was any long petioled or divided leaf found with the mildew. 
The upper and exposed side of the infested leaves became prematurely 
bright-colored over the attacked portion; while beneath, the conidiphores 
were short, quite evenly set, and when the spores were mature the char¬ 
acteristic frosty appearance prevailed. It is evident that this is not a 
favorite host for the peronospora, and in ordinary seasons the vines will 
very likely not suffer from it. The native species of ampelopsis (A. quin - 
quefolia) was often found near mildewed plants of the Boston ivy, but 
in no case was any of the fungus found upon this. It is, however, a 
well-known host. 
The last peronospora of the season is that of the cultivated violet, 
( V. odorata ), and was found upon leaves sent to the station by a grower 
of violets for the New York market, who claims that his crop is a fail¬ 
ure and the loss is hundreds of dollars. A comparison of this peron¬ 
ospora was made with P. violce , DBy., as found upon Viola tricolor 
var. arvense and distributed in Ellis’ N. A. F. (No. 2207). The latter 
is placed among the species with dichotomous (uniformly forking into 
two parts) branching of the spore-bearing threads. In the form upon 
V. odorata there is no indication of this form, but instead it is quite like 
the mildew upon the grape in the manner of bearing the spores. Again, 
the spores of the two are different in size, shape, and color. It is true 
