202 BOTANY. 



derground or in the substance of decaying wood. These 

 filaments are loosely interwoven, becoming in some cases 

 densely felted into tough masses or compacted into root- 

 like forms (Pig. 118, A, m). Sooner or later these under- 

 ground filaments produce the spore-fruits, which are 

 mostly umbrella-shaped, as in common Toadstools and 

 Mushrooms, or of various more or less irregular shapes, as 

 in the Pore-fungi, Club-fungi, etc. 



368. The Mushroom (Agaricus campestris) so commonly 

 cultivated may be taken to illustrate the mode of develop- 

 ment of the Toadstools (family Agao'icacem). The vegeta- 

 tive filaments compose the so-called "spawn" which grows 

 through the decaying matter from which it derives its 

 nourishment. Upon this at length little rounded masses 

 of filaments arise, which become larger and larger and 

 gradually assume the size and shape of the mature spore- 

 fruit, the Mushroom of the markets. 



369. At maturity the spore-fruit of the Mushroom con- 

 sists of a short thick stalk, bearing an expanded umbrella- 

 shaped cap, beneath which are many thin radiating plates, 

 the gills. Each gill is a mass of filaments whose enlarged 

 end-cells (basidia) come to, and completely cover, both of 

 its surfaces (Fig. 118, F/and VII). The basidia produce 

 spores in the usual manner for plants of this class, that is, 

 upon slender stalks. 



370. In the Pore-fungi {Polyporacem) the spore-bearing 

 cells line the sides of pores; in the Prickly Fungi {Hyd- 

 nacem) they cover the surface of spines; while in the Ear- 

 fungi {ThelephoracecB, Stereum, etc.) they form a smooth 

 surface. 



371. But little is known as to the sexual organs. 

 Several botanists have described such supposed organs 



