HOW TO USE THE KEY 



tipes. Turning to the full description of Collybia velutipes in 

 Chapter V(page 163) the identification is further corroborated. 



Another example of the use of the key might be in the case 

 of Lepiota americana. We have collected specimens of a 

 gilled mushroom having a prominent knob protruding from 

 the center of the cap. Looking in the key under "Form of 

 Cap," we find eight species mentioned. Reading their con- 

 densed tabulated descriptions, it is quickly found that only 

 one of them is said to be colored white with reddish scales 

 upon its surface. It is probable therefore that our specimens 

 are either Lepiota americana or else that they are some un- 

 common variety not mentioned in this book. 



Turning the pages next to the full description of Lepiota 

 americana, it is seen to tally in every respect with the specimen 

 before us and on the next occasion when this mushroom is 

 found, it is probable that it will be at once recognized as 

 would be the face of an acquaintance. 



It is the aim of the key, so far as it may be possible, to 

 assist the reader in identifying specimens of gilled fungi with- 

 out the necessity of ascertaining the color of their spores. 

 The reason for this aim is that it often requires many hours 

 to learn the color of spores by taking a spore print (see page 

 4). Nevertheless, a knowledge of the spore color of a mush- 

 room is one of the greatest of all helps in determining its iden- 

 tity, and such knowledge is often indispensable. ^ Spore prints, 

 however, are furnished by Nature and may be ready and 

 waiting for the collector's recognition. It is not uncommon to 

 find the colored spore-dust about growing mushrooms — 

 rusty, pink, white, purplish-brown or black dust, shed by 

 mature plants on their stems, on the caps of neighboring fel- 

 lows or upon the wood or ground that harbors them. These 

 indications of spore color should always be sought by the col- 

 lector and their presence should be noted. 



^ Figs, s to 8 and PI. lA. 



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