FUNGI 



381 



rately the graceful pattern of 



the gill edges. (See Figure 



178) 

 The spores of toadstools 



and of all other fungi which 



belong to the same group are 



borne at the ends of very 



slender branches which arise 



from a structure, usually club- 

 shaped, which is called the 



basidium. (See Figure i^g.) 

 When conditions are just 



right, the sporophores of fungi 



suddenly appear. Moisture, 



temperature, and the amount 



of food present in the hyphae 



are some of the conditions 



upon which the appearance of 



sporophores depends. This is well illustrated in the grow- 

 ing of mushrooms for market. Good mushrooms sell for 



as much as a dollar a pound, 

 and thousands of pounds are 

 grown artificially every year. 



The mushroom grower plants 

 what is called spawn. The 

 spawn of mushrooms is simply 

 a mass of mycelium in a state 

 of suspended animation. It is 

 the object of the mushroom 

 grower to get this spawn to 



Fig. 178. - The spore print of a ^ucc as many sporophores as 



mushroom. See context. — Afler ^ j r r 



Andrews. possible; the spreading of the 



Fig. 177. — A common edible mush- 

 room. The gills show plainly. 

 Note the ring of tissue surrounding 

 the stipe aijd. indicating the former 

 attachment of the edge of the 

 pileus. — After Gibson. 



