CASP0P3TTA. 179 



370. The Mushroom (Agarious campestris) so commonly- 

 cultivated may be taken to illustrate the mode of develop- 

 ment of the Toadstools. The vegetative filaments com- 

 pose the so-called " spawn" which grows through the de- 

 caying 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. . 



371. 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. 98, FT and VII). The basidia produce 

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

 upon slender stalks. 



372. In the Pore-fungi (Polyporus) the spore-bearing 

 cells line the sides of pores ; in the Prickly Fungi (Hydnum) 

 they cover the surface of spines; while in the Ear-fungi 

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



373. But little is known as to the sexual organs. Several 

 botanists have described such supposed organs upon the 

 vegetative filaments before the formation of the spore- 

 fruit, but there are still some doubts as to the correctness 

 of the observations. 



374. The vegetative filaments (mycelium) of some species 

 of this order (as Polyporus fomentarius, etc.) often form 

 thick, tough, whitish masses of considerable extent in 

 trees and logs, and constitute the Amadou, or German tin- 

 der of the shops. 



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



