CHAPTER XXV 



BASIDIOMYCETES 



In the Basidiomycetes, the gonotocont forms its spores exogenously 

 in the manner of conidiophores instead of endogenously as in the Asco- 



mycetes. The sporophore is called the 

 basidium and the spores basidiospores. 



The mycelium of the Basidiomycetes is 

 divided, according to its morphological and 

 cytological relationships, into three classes 

 which are called primary, secondary and 

 tertiary, because of their sequence in time 

 (Falck, 1909; Bensaude 1918). 



The primary mycelium comes directly 

 from the germinating basidiospore and in 

 most families is developed as the usual 

 vegetative hyphae; in a few, it possesses 

 the character of sprout mycelium, for the 

 most part transitorily and under definite 

 conditions of nourishment. The hyphae 

 are comparatively slender; they intertwine 

 irregularly and anastomose so generally 

 that sometimes a real mycelial net results. 

 The branches are approximately equal to 

 the main axis in form and size. 



According to the cytological relation- 

 ships, these mycelia produced from the 

 basidiospores may be divided into four 

 types, partly related to the nuclear condi- 

 tions of the basidiospores themselves. In 

 the first type, to which, among others, 

 belong Corticum varians, Peniophora Sam- 

 buci (C. serum), and Collybia conigena 

 (Kniep, 1915, 1917, 1919) and most of the 

 Uredinales, the mature basidiospores and 

 the cells of the primary mycelium are 

 uninucleate (Fig. 263, 2 to 4). 

 In the second type, which includes Peniphora gigantea (Kneiffia 

 gigantea), the mature basidiospores are binucleate, but only one nucleus 



396 



Fig. 263.- — 1. Collybia conigena. 

 Uninucleate hyphae producing 

 oidia. 2 to 4. Corticium varians. 

 Germination of basidiospore. ( X 

 670; after Kniep, 1917.) 



