4 G. MASSEE ON BASIDIOMYCETES. 



attention will be chiefly directed to three leading ideas, which 

 have been persistently followed, and the gradual perfection of 

 which has resulted in the building up of the Agaricinse, the most 

 modern group, at the same time the most perfectly adapted to 

 existing requirements, as proved by its universal distribution and 

 immense numbers. 



The points are : (1) The production of the largest area of hyme- 

 nium or spore-bearing surface, with the least possible expenditure 

 of material ; (2) The protection of the hymenium from rain, 

 dust, etc. ; (3) The protection of the spore-bearing structure from 

 living enemies, and the facilitation of spore dispersion. The 

 gradual evolution of these points will be compared and contrasted 

 in the following families of the Hymenomycetes : — Clavariece, 

 Thelephorese, Hydnese, Polypor£e, Agaricinse. 



Clavarie.e, — The oldest type, and consequently showing the 

 least amount of differentiation, although within the group itself 

 there is a marked advance in the perfection of those ideas which 

 are so pronounced in the higher families. In Clavaria, the 

 central genus of the group, the simplest forms consist of a 

 «obweb-like spreading mycelium, from which minute, club- 

 shaped, erect s2)oro2)hores or fertile portions spring, every portion 

 of which is covered by the hymenium or spore-bearing structure. 

 In other species the clubs are larger, but still simple or typically 

 club-shaped — hence the name of the group. In one British 

 species — Clavaria pistillaris, the clubs or individual plants are 

 four to seven inches high and often more than an inch in 

 ■diameter at the thickest part. The special point of progress 

 •observable in this group consisted in the gradual modification of 

 the original simple club-shaped sporophore into a branched 

 one, and this idea is carried to the extreme in such species as 

 Clavaria ahietina and C. coralloides, where the fungus resembles a 

 much -branched tree in miniature, the numerous slender branches 

 being everywhere covered by the hymenium ; and although in 

 the two last-named species the weight of an entire specimen is 

 much less than of Clavaria pistillaris, nevertheless the area of 

 spore-bearing surface is very much greater than in the last- 

 named species, due to the branching of the sporophore. In 

 .Sparassis, the most highly differentiated genus in the family, 

 the entire structure consists of thin, much contorted plates, 

 entirely covered with the hymenium, the whole resembling, in 



