592 



MUSHROOMS, EDIBLE AND OTHERWISE 



cured in the market in two forms, flake spawn and brick spawn. In both forms 

 the mycelium growth is started on a prepared medium mainly consisting of 

 manure and then arrested and dried. The flake spawn is short-lived by reason 

 of its loose form, in which the mycelium is easily accessible to the air and de- 

 structive bacteria. It deteriorates rapidly in transportation and storage and can 

 only be used to advantage when fresh. Growers, especially in the United States, 

 have therefore discarded it in favor of brick spawn, which affords more protec- 

 tion to the mycelium and can be safely transported and stored for a reasonable 

 period. 



Until recently the manufacturer of spawn was compelled to rely entirely 

 upon the caprice of nature for his supply. The only method known consisted 

 in gathering the wild spawn wherever nature had deposited it and running the 

 same into bricks or in loose material, without reference to variety. Neither the 

 manufacturer nor the grower had any means of ascertaining the probable nature 

 of the crop until the mushrooms appeared. 



Figure 503. Agaricus villaticus. 



PURE CULTURE SPAWN. The recent discovery of pure culture spawn 

 in this country has made possible the selection and improvement of varieties of 

 cultivated mushrooms with special reference to their hardiness, color, size, flavor 

 and prolificness, and the elimination of inferior or undesirable fungi in the crop. 



