Ervsiphe 189 



The plant issued as *'var. delphiniV (on stems of DclpJiiiiuini) 

 Ell. & Everh. N. A. Fung. no. 835 does not differ from many 

 common forms of E. polygenic and cannot be separated from the 

 type. 



An interesting ErysipJie has been sent to me by Professor Mi- 

 yabe from Japan (Kyoto, April, 1899, coll. T. Nishida), growing 

 on Qucrnts glauca, which I cannot separate from E, polygoni. This 

 form has a rather distinct habit ; the persistent, thin, siibcrustace- 

 ous mycelium forms definite patches on the upper surface of the 

 leaf, and on these the perithecia are more or less gregarious. The 

 diameter of the perithecium is about 90 // ; the asci are 4-6, ovate to 

 ovate-oblong, often without a stalk, 50-58 x 30—35 /^, spores 4-6, 

 21 X 10 /^. The appendages are from 2 to 3 times the diameter of 

 the perithecium, rather numerous but distinct, colorless, becoming 

 shining, and are more or less irregularly bent, or geniculate, at in- 

 tervals. Except in the rather marked habit, the fungus does not 

 differ in any w^ay from many common forms of E, polygoiii. This 

 is the first record of the occurrence of an Erysiphe on Qno'ais in 

 the Old World. The Californian E, trnia on Qjterais agrifolia is 

 quite distinct from the present form. 



The record of E. Martii by Cooke (S3) on Popiilus ciliata 

 is an error, the fungus being Uncimda salicis. The specimens 

 published as E, Martii in Rab. Fung. Eur. 1737, on Rubia pcrc- 

 grina^ and in Roumeg. Fung. Gall. nr. 3316 on Aspcnda odoraia 

 are some sphaeriaceous fungus. 



E, polygoni is the cause of the disease knowm as the '* blight" 

 or "mildew'* of several cultivated plants of economic importance. 



In the first place, it causes the *' bean " and "pea blight," 

 well known to market gardeners. Bessey (40), speaking of this 

 disease in the United States, says, "pea blight has for many years 

 been very destructive to late peas in the West ; it has, in fact, 

 rendered the growth of the later varieties in some instances al- 

 most impossible." As regards remedies against the disease, Gal- 

 loway (135) mentions a case wdiere a crop of beans badly mil- 

 dewed was "thoroughly dusted with flowers of sulphur, and in a 

 week the fungus had entirely disappeared, and the plants produced 

 a good crop." The following advice is given: "A powder made 

 by mixing equal parts of air-slacked lime and flowers of sulphur 



