280 



STRUCTURE AND LIFE HISTORIES 



with the gills down over a piece of white paper, and left 

 for a few hours, a dark purplish deposit will form in lines 

 under each gill. With Amanita the color is white. This 

 deposit (the " spore-print ") is composed of spores, shed from 

 the surfaces of the gills (Fig. 202). Microscopic examina- 



FIG. 204. The meadow mushroom (Agaricus campestris, var. Colum- 

 bia.} Young fruiting bodies (carpophores). The mycelial hyphae arc in 

 the substratum. (Photo by G. F. Atkinson.) 



tion discloses the fact that the gills are composed of a net- 

 work of hyphae. Their surface is covered with innumer- 

 able short, thick, club-shaped bodies, filled with proto- 

 plasm (Fig. 203) . These are the basidia (singular basidium) . 

 Fungi which bear basidia are grouped together as Basidio- 

 mycetes. At the tip of each basidium are two tiny projec- 



