IV.] FUNGI. 357 



5. Natural Order, Fungi. — The Mushroom and Mould 

 Family. 



Type — Any species of Agaric [Agaricus). 

 With a vegetative system growing under the surface of 

 soil containing decaying organic matter, and consisting of a 

 flocculent network of delicate cellular threads, forming what 

 is called the mycelium. The fructification is borne above 

 the surface, in the form of an umbrella-like disk called the 

 pileus, upon a stout stem. The margin of the pileus is at 

 first united by a membrane to the stalk, from which it 

 breaks away, leaving a ring-like scar. Upon the under-side 



Fig. 239. Mushroom (A^artcus). 



of the pileus numerous vertical plates radiate from the top 

 of the stem to the margin of the pileus. If a very thin, 

 transverse section of one of these plates be cut with a sharp 

 knife, and examined under a powerful microscope, the sur- 

 face will be found to be studded with large cells, each of 

 wliich bears four very minute stalked spores upon its apex. 



