THE TlIALLOPnvrA 



301 



cap or pileus, from the under surface of which hang the gills. A 

 few of the species arc regularly cultivated and constitute a food 

 product of sonic importance. A number are also poisonous, and 



Fig. 177. — A pore fungus. Bnickot-liko fructification of one of the specie 

 which grows on tree-trunk.s. /I, lower surface, showing pore openings. B, upper 

 surface. C, section through a part of the fructification, showing the long, tube- 

 like pores, on the inner surfaces of which the spores are borne. This type of 

 fructification adds a new layer each year, and two such annual layers are here 

 evident. 



-Puff-balls. Cleneral api)carance of young and of mature 

 fructifications. 



the amateur mushroom collector is always in danger of adding 

 them to his menu. In the polypores (Polyporaceae, Fig. 177) the 

 hymenium lines narrow tubes which open by pores on the surface 

 of the pileus. These include many mushroom-like types as well 



