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TEXTBOOK OF BOTANY 



Fig. 247. Reproductive structures of three species of fungi: A, the sulfur mush- 

 room (Polyponis sulphur ens) ; B, a coral fungus (Clavaria) ; C, stink -horn 

 (Dictijophora) . Photos from W. G. Stover and R. B. Gordon. 



The common meadow mushroom may produce 2 biHion spores, a 

 polypore 10 bilHon, and a good-sized puffball may have 7000 bilHon 

 spores. It has been estimated that only about one spore out of each 

 trilhon spores ever develops into a new plant. The appearance of fruiting 

 bodies is illustrated in Figs. 234 and 247. Owing to the club-shaped 

 hypha on which their spores are borne, such fungi as toadstools, puff- 

 balls, smuts, and rusts are called Basidiomycetes. There are more than 

 20,000 species of basidiomycetes. Some mushrooms are basidiomycetes, 

 but others are ascomycetes. 



The culture of the common meadow mushroom is an important indus- 

 try in scattered localities, where it is carried on in specially constructed 

 buildings with insulated walls, in caves, or in old mine tunnels where 

 the temperature and humidity can be controlled. Light is not harmful, 

 but it is not necessary; and it increases the difficulty of controlling other 

 conditions. After the beds of soil rich in organic matter are prepared and 

 sterilized, they are inoculated with pieces of mycelia of pure races. These 



