Erysiphe 209 



this example among simple haustoria some occur which are dis- 

 tinctly lobed (Fig. 131). These latter are not quite so large and 

 certainly not so much lobed as in typical E. galeopsidis, but their 



occurrence tends to break down the distinction between the two 

 forms. 



Whilst, therefore, admitting that the form known as E. gale- 

 opsidis on Galeopsis, Laiuium, Stachys, etc., is well characterized 

 by the large, lobed haustoria and absence of spores on the living 

 host plant, it seems that forms of E. cichoraccarum exist in which 

 the latter (and to some extent the former) character is found. 

 Whether these intermediates are numerous enough to compel us 



•ileopsidis 



X the former 





J>3i 



should rank as a species, or more probably as only a variety, can 

 only be proved by further observations, especially with regard to 

 the haustoria of specimens of E. cichoraccaruin on its numerous 

 host-plants. For this purpose young examples are in many cases 

 necessary, as the mycelium is commonly evanescent in the mature 

 condition of the fungus. 



4. E. GRAMINfS DC [Figs. 156," 159, 160] 



Erysiphe graminis DC. Fl. Fr. 6: 106. 1815; Lev. Ann. 

 sci. nat. III. 15: 165. //. 10. / S3. 185 1; Tul. Sel. Fun 

 Carp, i: 212. 1861 ; Cooke, Micr. Fung. 220. //. //. / 

 236. 1865 ; Cooke, Handb. Brit. Fung. 2: 651. 1871 ; Kars't' 

 Myc. Fenn. 2: 193. 1873; Sacc. Syll. Fung, i: 19.' 1882; 

 Wint. in Rabenh. Krypt. Fl. Deutschl. i^ : 30. 1884; Karst. 

 Act. Soc. Faun. Fl. Fenn. 2 : 93. 1885 ; Burr, in Ell. & Everh. 

 N. Amer. Pyren. 15. 1892; Jacz. Bull. I'Hcrb. Boiss. 4 : 728. 

 1S96; Oudem. Rev. Champ. Pays-Bas. 2; 98. 1897. 



Alphitomorpha communis, var. graminearum Wallr. Berl. Ges. 

 Nat. Freund. Verh. i : 31. 1819; Wallr. Fl. Crypt. Germ. 2 : 



71^. 1833. 



Erysibc communis, var. graminum Lk. in Willd. Sp. PI. 6 : 106. 



1824. 



Erysiphe communis Fr. Syst. Myc. 3 : 239 (partim). 1829. 

 E, communis, var. graminum Duby, Bot. Gall. 2 : 869. 1S30 ; 

 Rabenh. Deutschl. Krypt. Fl. i: 232. 1844. 



E. communis, var. graminis Dur. & Mont. Fl. d' Alger. (Crvpt.) 

 565. 1846-9. 



