Observations on the development of Uncinula spiralis. ! 
B. T. GALLOWAY. 
WITH PLATES XXXII AND XXXIII. 
At the meeting of this Association held in Indianapolis in 
1890, the writer presented a note on Uncinula spiralis B. 
C., calling attention to a number of experiments which es- 
on Ampelopsis. Since presenting the note in question some 
additional studies on the life history of the fungus have been 
afforded. 
The fungus in question, commonly called the grape pow- 
dery mildew, is widely distributed in this country, occurring 
on various species and varieties of Vitis and also on A mpelopsts 
quinguefolia. In California and elsewhere on the Pacific 
coast the fungus is especially prevalent on varieties of Vztts 
vinifera, and it also attacks these plants in the eastern United 
States when grown out of doors and in greenhouses. What is 
doubtless the same fungus occurs in Europe, where it has long 
been known as Osdium T,; uckeri. The native spore form of 
this fungus was wanting, however, for a long time on Euro- 
pean vines, and it is only recently that Prillieux? has noted 
its occurrence in France. According to Prillieux, the per- 
ithecia found in Europe do not differ materially from those 
ner, and others, that the forms are identical. The present 
T e Uncinula usually becomes sufficiently abundant to be 
easily found on cultivated varieties of grape, as well as on 
Ampelopsis, earlyin July. Toward the latter part of August 
pe Ure ition GA. A. A. S. Seetneteis mecine Ansut, UAE 
re . - - - -» , gus id = 9° 
A *Sur les perithéces de I’ Uncinula rer - France et Tidentité de l’Oidium 
Pope si de Il’ Oidium Européen. Bull. de la Soc. Mycologique de France 
[486] 
