230 PHYLUM VII. CARPOMYCETEAE 



ground by the rapid growth of a central mass of stalk 

 tissue, and later by a rupture of tissues the hymenium be- 

 comes external. 



386. At maturity the spore fruit of the Mushroom 

 consists of a short thick stalk, bearing an expanded um- 

 brella-shaped cap, beneath which 

 are many thin radiating plates, the 

 gills. Each gill is a mass of fila- 

 ments whose enlarged end-cells 

 (basidia) come to, and completely 



FIG. in. Development of cover, both of its surfaces. The 



basidia produce spores in the usual 



manner for plants of this class, that is, upon slender stalks. 



387. In the Pore fungi (Polyporaceae) the basidia line 

 the sides of pores; in the Prickly Fungi (Hydnaceae) and 

 Coral fungi (Clavariaceae) they cover the surface of spines 

 and branches; while in the Leathery fungi (Thelephora- 

 ceae, Stereum, etc.) they form a smooth surface. 



388. Nothing is yet known as to their sexual organs. 

 Several botanists have described such supposed organs 

 upon the vegetative filaments before the formation of the 

 spore fruit, but there are grave doubts as to the correct- 

 ness of the observations, and it is the general opinion that 

 these organs have become obsolete. 



389. The vegetative filaments (mycelium) of some 

 species of this order (as Fomes fomentarius, etc.) often 

 form thick, tough, whitish masses of considerable extent 

 in trees and logs. 



390. We know but little as to the germination of the 

 spores and the subsequent development of the vegetative 

 filaments. 



391. Several families of more or less reduced basidium 

 fungi which probably have been derived from the fore- 

 going families, as the Ear Fungi (Auriculariales) , Jelly 



