CARPOPHYTA. 179 
870. The Mushroom (Agaricus 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, VZand VIZ). 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 
