Notes ON THE ERYSIPHACEAE 193 
The fungus recorded by Raciborski (60) as Oidium tabaci 
from Java is probably the conidial stage of E. cichoracearum. 
Examples of the form of £. céchoracearum (on Galium) with 
perithecia containing asci without any trace of spores (see mono- 
graph, p. 208) occur in the Paris Museum, labelled “ &. Martii Lév. 
sur Galium. Souk el Arba [Algeria]. ter Janvier 1893.” 
As E. cichoracearum frequently proves a serious enemy to 
cucumber culture—more especially to cucumbers forced in the 
greenhouse for a winter cropthe following notes on the success- 
ful treatment of the disease may be given. Humphrey (31*) 
states: “The disease may be kept in check in the greenhouse by 
spraying the plants as often as is necessary with a solution of 
Sulphide of potassium (liver of sulphur) in water, an ounce of the 
sulphide to four gallons of water. A stronger solution injures 
the plants and fruits. Spraying with ammoniacal carbonate of 
Copper (3 oz. carbonate of copper dissolved in one quart of am- 
monia ; dilute with water to 2 5 gallons) has been found even more 
effective. But Professor Bailey’ finds more effective than either 
€xposure to sulphur vapor. This is accomplished by closing the 
house as tightly as possible for half an hour or an hour at a time, 
while it is filled by the vapor arising from a vessel of sulphur kept 
a little above the melting point on a small oil stove. The vessel 
should be porcelain-lined, to protect the iron from the action of 
the sulphur. Great care must be taken'to avoid the ignition of 
the sulphur.” It may be noted that Humphrey found that the 
conidia of E. cichoracearum on cucumber leaves differed consider- 
ably in size in examples from different localities. 
_ Stewart (81) records cases of field-grown cucumbers thickly 
bn with mildew. (See also for ‘ Cucumber mildew,” Bailey 
=). 
Oidium chrysanthemi Rabenh. Hedwigia, 1: 19-21. pl. 3. f. 2: 
1853, is probably the conidial stage of E. cichoracearum, and 
and frequently very troublesome on cultivated chrysanthemums. 
The fungicides recommended above should be used to check the 
disease, 
E. GaLeopsipis DC. (Monograph, p. 204) 
Distrib. add : Europe: Bulgaria (10). 
Asia : Siberia, Yeniseisk, “flum. Yenisei inter 58° et 71°” 
