328 



PRACTICAL COURSE IN BOTANY 



while the favorite edible kind (Agaricus campestris), though 

 white-gilled when young, produces dark, purple-brown spores 

 that cannot fail to distinguish it clearly for any one who will 

 take the trouble to make a print. 



378. Economic properties. — Most of the wood-destroy- 

 ing fungi belong to this and allied orders. They are among 

 the worst enemies the forester has to deal with (140), and 



millions of feet of 

 lumber are destroyed 

 every year by them. 



Over seven hun- 

 dred kinds of fungi 

 growing in the United 

 States have been de- 

 scribed as edible, but 

 the evil repute into 

 which the whole class 

 has been brought by 

 the poisonous quali- 

 ties of a few species, 

 and the difficulty, to 

 any but an expert, of 

 distinguishing be- 

 tween these and the harmless kinds, has caused them to be 

 generally neglected as articles of diet. While they are 

 pleasant relishes and furnish an agreeable variety to our daily 

 fare, their food value has been greatly exaggerated. They 

 contain a large proportion of water, often over 90 per cent, 

 and the most valued of them, the Agaricus campestris, is 

 about equivalent to cabbage in nutrient properties. 



Fig. 468. — Portion of the root of a maple afifected 

 with rot caused by the mycelium of a fungus that 

 has penetrated to its interior. 



Practical Questions 



1. Why are mushrooms generally grown in cellars? (186, 343.) 



2. Name any fungi you know of that are good for food or medicine or 

 any other purpose. 



3. Name the most dangerous ones you know of. 



