HEMIBASIDIOMYCETES 



339 



this structure, Brefeld placed Pilacre in the Protobasidio- 

 mycetes. 



A vertical section of a species of Pilacre resembles 

 superficially that of a typical Lycoperdon, although there is 

 no near affinity between the two. 



The stem is solid, and expands at the apex into a more 

 or less globose head or columella, from which the fertile 

 hyphae originate. These hyphae are densely crowded 

 and radiate in every direction, forming a globose head. 

 Each hypha gives off at different levels short lateral 

 branches which bear clusters of protobasidia. Each 

 hypha runs out into a sterile terminal portion furnished 

 with variously coiled and contorted branches. These 

 sterile tips become more or less interwoven and linked 

 together by their spiral branches, and collectively form 

 a kind of external protective covering or peridium, which 

 encloses the central spore-producing mass of hyphae. 

 The fruit is thus said to be angiocarpous. 



Tremelleae 



The species are soft and gelatinous when moist, be- 

 coming rigid and horny when dry, but again becoming 

 gelatinous when moistened. According to Brefeld and 

 others, the basidia are longitudinally divided by two septa 

 crossing each other at right angles. I am not convinced 

 that this is the true explanation of the appearance pre- 

 sented by the basidia. When quite young the basidium 

 appears as a smooth, broadly obovate body terminating a 

 slender hypha. As it increases in size, when viewed from 

 above, two very slight depressions crossing at right angles 

 are visible on its upper surface. The four portions of the 



