HYMENOMYCETES 349 



one side of the sporophore fertile, or covered with the 

 hymenium, while the other side is sterile and protective. 

 A section at once reveals the true structure. Acurtis, 

 included by Saccardo under the Clavariaceae, is a spurious 

 genus founded on abnormal growth. 



In the Ascomycetes the genus Xylaria has the sporo- 

 phore clavate, and either simple or branched, and super- 

 ficially resembling species of Clavaria, from which it is 

 distinguished by the absence of basidia, and the presence 

 of asci. 



Finally, some authors have removed the genus Sparassis 

 from the present family and placed it in the Thelephoraceae. 

 This is undoubtedly a mistake. As already stated, one sur- 

 face of the sporophore is always sterile ; in other words, 

 the hymenium is confined to one surface in the last-named 

 family, and the whole structure is tough and elastic. In 

 Sparassis the substance is crisp and very brittle, and both 

 surfaces of the folds of the sporophore are covered by the 

 hymenium, as in all species included in the Clavarieae. 



Thelephoreae 



The dominant character of this family is the even surface 

 of the hymenium. In Hypochnus, the most primitive genus, 

 the characteristic feature of the Hymenomycetes, that is, a 

 continuous, compact spore-bearing surface or hymenium, is 

 absent, and it is only owing to the presence of typical 

 basidia that it is included in the Basidiomycetes. The 

 sporophore consists of very loosely interwoven hyphae 

 trailing over the substratum, like some mould, and the 

 tetrasporous basidia are produced in small, scattered 

 clusters. Hypochnus is very closely allied to Zygodesmus, 

 a genus usually placed in the Hyphomycetes or moulds, 



