[Vol. 12 

 302 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



undifferentiated hypha, numerous in the subhymenium; cystidia 

 incrusted or not incrusted, 30-60 X 6-10 n; spores hyaline, even, 

 10-13 X 3-4 (x. 



Fructifications 2-10 cm. long, 1-3 cm. broad. 



On bark of fallen limbs of Populus and other frondose species. 

 Canada to New York and westward to Washington, in West 

 Indies, and in Europe. 



The type of P. Allescheri and specimens of similar structure 

 cited below differ so slightly from P. mutata that I have separated 

 them from the latter only by all their gloeocystidia being of 

 slender elongated form and perhaps specially differentiated 

 middle portions of hyphae, while the gloeocystidia of P. mutata 

 are terminal portions of hyphae and hyphal branches which are 

 in many cases pyriform and in others afford indication by a pyri- 

 form base of having finally grown out from a pyriform body into 

 an elongated gloeocystidium. It may be that when someone 

 can keep under observation and examination a specimen of 

 P. mutata during its season, he may find that pyriform gloeo- 

 cystidia are present abundantly up to the time of copious spore 

 production and then finally all become elongated so that the 

 fructification would be referable to P. Allescheri. In this event 

 P. Allescheri will become a synonym of P. mutata by priority 

 of the latter. 



While P. mutata has become correctly understood in Europe 

 through my exchanges with Bresadola there is a misunderstanding 

 there concerning P. Allescheri. Von Hohnel & Litschauer 

 studied the original specimen of P. Allescheri in Bresadola Herb, 

 and state, loc. cit., that this consists of a mixture of fructifications 

 of P. cremea and P. Allescheri, the latter as described by Bresadola 

 and figured in his plate. The specimen shared with me by Bresa- 

 dola is in such close agreement with the plate that the colored 

 drawing of the upper figure may have been made from it, and it 

 agrees also with the description. Its data as to collection is given 

 "ad corticem Fagi silv. Bavaria. Allescheri The portions of the 

 original specimens communicated to Bourdot & Galzin and to 

 Miss Wakefield are apparently of the P. cremea component, 

 referred to by v. Hohnel & Litschauer. 



Specimens examined: 



