BOLBITIUS FLAVIDUS 71 



comparison makes it clear that during the expansion of the pileus 

 the paraphyses about double theJr superficial area, whilst the shafts 

 of the basidia remain unchanged. The number of paraphyses which 

 enclose the shaft of each basidium varies from three to five, but is 

 most often four. 



The basidia are monomorphic, i.e. they are all of about the same 

 length and equally protuberant at maturity. This is shown in 

 Fig. 35 which represents semi-diagrammatically a cross-section 

 through the hymenium and subjacent cells. The monomorphism of 



Fig. 35. — Bolbitius flavidus. Semi-diagrammatic vertical section througli the 

 hymenium shortly after the beginning of spore-discharge. The paraphyses 

 and subhymenium are unshaded. The basidia are in various stages of 

 development : a, youngest basidium, not projecting ; b, older basidium, pro- 

 jecting above paraphyses ; c, sterigmata developing ; d, spores developing ; e 

 and /, spores growing larger ; g, spores full size but unpigmented ; /(, i, j, 

 spores becoming brown ; k, spore -discharge in progress, two spores have 

 already been discharged and a third, with a drop of water excreted at its 

 hilum, is about to be discharged ; I, all four spores have been discharged ; 

 m, collapsed basidium. Magnification, 352. 



the basidia is correlated here, as in the Panaeolus Sub-type, with the 

 fact that adjacent basidia do not bear full-sized spores at one and 

 the same time. In being monomorphic and not polymorphic, the 

 basidia of Bolbitius flavidus differ in a striking manner from those 

 of Lepiota cepaestipes, Psatkyrella disseminata, and all species of 

 Coprinus, for in these fungi the basidia are dimorphic, trimorphic or 

 tetramorphic. 



The shape of the basidia is peculiar : the narrow shaft, on passing 

 to the exterior of the hymenium, becomes rather suddenly swollen 

 into a rounded extremity upon the end of which are developed the 

 four sterigmata (Fig. 35). This form of basidium-body may be of 

 general occurrence in Bolbitius, for I have noticed it in another 



