198 Transactions British Mycological Society. 



C. Kewensis Mass., in Journ. Bot. 34, 1896, p. 470. = C. 

 stricta. 



C. Krombholzii Fr., Epicr. p. 572. The figures of Krombholz 

 on which this species was founded may have been forms of 

 either C. Kunzei or C. rugosa, possibly both. No species 

 distinct from either that would answer to C. Krombholzii has 

 been seen by the authors. 



C. pyxidata Pers., Comment, p. 47, tab. i, fig. i. Possibly 

 an abnormal form of C. stricta, since it occurred on wood. 



C. rufa Pers., Comment, p. 71, = C. inaequalis. (See these 

 Trans, iii. p. 33.) 



C. rufescens Schaeff., Icon. Fung. tab. 288. = C. botrytis. 



C. spinulosa Pers., Obs. Myc. 2, p. 59, tab. 8, fig. i. Inde- 

 terminable. 



C. striata Pers. ; Persoon's figure suggests a discoloured 

 C. vermicularis. 



C. tiiberosa Sow., Col. Fig. tab. 199. The figure suggests an 

 abnormal form of C. fistulosa, but was referred by Fries and 

 Quelet to the genus Calocera. Probably not determinable. 



C. imcialis Grev. = Pistillaria. 



THE OCCURRENCE OF OAK MILDEW 

 ON BEECH IN BRITAIN. 



By A. D. Cotton, F.L.S. 



The fungus which now so generally occurs on coppiced oak 

 in this country was first noticed in Europe in 1907 and was 

 probably introduced from America. Its spread in Europe 

 was remarkably rapid and by 1909 it was known from almost 

 every European country and had moreover spread through 

 Turkey into Asia Minor. 



The fungus for a time remained unnamed since, owing to 

 the absence of perithecia, it was impossible to determine its 

 generic position. In 1910 Griffon and Maublanc named the 

 conidial stage Oidium alphitoides, and the following year Arnaud 

 and Foex recorded the occurrence of occasional perithecia 

 production from which it was apparent that the fungus was a 

 Microsphaera, and was regarded by them as a form of M. Alni. 

 This view has in the main received acceptance and is endorsed 



