175 



P. myrtillina Schub. on leaves of V>n-<-n /////// Mi/rtillii* (bil- 



berry), V. ////'// 'muttim, and />'//>//< /V"/// />///////// (crowherry ). (I'.S. 

 America). 



Erysiphe. 



The perithecia contain several asci, each with two to ei-ht 

 oval hyaline spores. The appendages are like these of N//A^-- 

 ,;,tli>,-u, .simple and thread-like. 



Erysiphe graminis 1 >. C. Mould or mildew of grass and 

 wheat, (Ira-s and cereals, especially wheat, often suffer serious 

 damair from this parasite. The mycelium appears on the leave-, 

 as white or brownish spots, generally on the upper sun 

 Colourless conidia (Oiilium monili<>i<l>, Lk.) are produced acro- 

 petally in chains. The somewhat rare perithecia have la-own 

 appendages, and contain eight to sixteen asci, with four to 

 ei-ht spore- each : the spores mature in spring as the dead 

 leaves lie on the ground. This mildew has inllicted -r. 

 lo-s 1 mill in Europe and America. Ihi-tinu the threatened 

 'Top with "flowers of <ulphur " will 

 probably check the first stages .!' an 

 attack, but care in destroying infected 

 <-rop.> is liy far the most effective 

 preventive. 



Erysiphe martii Lev. Thn fre- 

 quents various I.e^uminosae (clover, 

 beans, vetches, peas, lupine-;, etc.), 

 'ruciferae, and other jdants (Britain 

 and I'.S. America). 



Er. umbelliferarum 1 e I'.ny. 

 ( iccin- on various rmbelliferae 

 i I'.ritain). 



Er. communis Wallr. on tobacco, also "ii various b'auun- 



eiilaci-ae, rajiilionaceae. etc. (I'.ntain and I'.S. America i. 

 Er. tortilis Wallr. on Cormis xmii/fin"/ il'.riiain an 



America). 



Er. galeopsidis I . C. n l.abiatae il'.riiain and 



America). 



Er. cichoriacearum I >. C. on Compositae, Boragineae 



il-o can-in- i-'.n-idei'able dama-e !o ciiciimbei - il'.riiain 

 I S. America i. 



:i.iti"ii "i .1 f..]ii.liuiii i 



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Un-llt-'li-<- lia> ' 



UL-i-iii-tiilii- l,.i-, |.. n, i? 



! IKllI 

 (. \ltlT I I. I 



d I'.S. 



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