AUTOBASIDIOMYCETES 443 



folds or veins. The sporophores are generally fleshy, with a defi- 

 nite cap, or pileus, usually provided with a central stalk, but also 

 excentric, sessile, etc. Marasmius, Clitocybe, and Armillaria are 

 some of the principal parasitic genera. 



Corticium, including resupinate species without setae (cystidia) 

 on the hymenium. The spores are generally small, hyaline, and 

 without appendages. 



Stereum is a diverse genus with broader characteristics. The 

 sporophores are differentiated into several layers. They are only 

 partially if at all resupinate, and often shelving, or even slightly 

 stalked. 



Hydnum. The sporophores are provided with awl-like teeth 

 arising from tuberculate, branched, or cap-like portions of the 

 sporophore. No cystidia are present. 



Fomes, with sporophores generally bracket-like or hoof-shaped, 

 sessile or stalked, and woody even when young. The pores are 

 narrow, and the tissue between these is heterogeneous with the 

 general tissue of the sporophore. 



Polyporus is similar to the preceding, except that the sporophore 

 is at first fleshy, becoming harder, and it may be exceedingly diverse 

 in form and size. 



Trametes. In this genus the species are generally of the texture 

 of Fomes or Polyporus ; but the general tissue of the sporophore 

 penetrates between the pores, so that there is homogeneity of 

 substance. 



Marasmius is a genus of the relatively small gill-bearing fungi 

 in which the plants become dry, yet, when remoistened, regain 

 much their original forms. The cap is fleshy to leathery, the gills 

 tough and distant, producing white spores, and the stipe cartilagi- 

 nous or horny. 



Clitocybe, with more or less fleshy cap and stalk, the latter 

 centrally placed, is characterized by decurrent gills (lamellae) and 

 by the absence of any appendages, such as veil or volva. The 

 spore powder is white and the spores hyaline. 



Armillaria. These forms are quite similar to the preceding ex- 

 cept that when young the cap is attached to the stem by a veil, 

 which upon breaking forms a more or less persistent ring (annulus) 

 on the stem. 



