THE HYMENOMYCETES 



26T 



of Fig. 237) and in a ring attached to the stalk below the gills 

 (Fig. 237, r), while in certain types (Amanita, etc.) there is a 

 large cup (volva) at the base of the 

 plant out of which the stalk rises. 



It is becoming rather general popu- 

 lar usage to apply the term mushroom 

 to all toadstools and other fleshy 

 fungi which are edible. There are no 

 general rules for distinguishing mush- 

 rooms from toadstools which do not 

 have exceptions; but the collector 

 may readily learn the characters of 

 the most -poisonous species, and like- 

 wise become acquainted with a num- 

 ber of choice forms which are easily 

 recognized. 1 It is a good principle, 

 however, to rest satisfied with a 

 knowledge of a few absolutely safe 

 mushrooms and not to experiment 

 with those that are not fully known. 



The most poisonous species of the gill ^ *.'* 



r FIG. 238. Gills of mushroom 



fungi are in the genus Amanita and . (Coprinus comatus) 



have large volvas, rings, and white Across section of gills showing 



spores, and may be readily recognized fruiting surface (hymenium) ; 



when carefully examined. There are 



also some very poisonous species of 



Boletus among the pore fungi. The 



commonest mushroom of the market 



(Agaricus campestris) is a form extensively cultivated, but 



which also grows in the fields. These mushrooms are raised 



in cellars and caves, in specially prepared, heavily manured 



beds, which are planted with masses of mycelium called 



1 See Farlow, " Some Edible and Poisonous Fungi," United States Depart- 

 ment of Agriculture, Division of Vegetable Physiology and Pathology, Bul- 

 letin 15, 1898. 



, portion of fruiting surface 

 illustrating three basidia with 

 spores and two from which 

 the spores have fallen off, 

 showing the spore-bearing 

 stalks (sterigmata) s 



