GROUPS OF PLANTS. 33 



times it is shiny and white. While it does not possess the warty 

 scales found in the fly agaric, it has occasionally a few mem- 

 branous patches. 



Identification of Edible Fungi. — Various rules have been 

 given for distinguishing the edible from the non-edible fungi, 

 many of which are practically worthless, but the following ^ which 

 have been formulated by Professor William G. Farlow, are well 

 worthy the attention of the amateur collector: 



" I. Avoid fungi when in the button or unexpanded stage; 

 also those in which the flesh has begun to decay, even if only 

 slightly. 



" 2. Avoid all fungi which have stalks with a swollen base 

 surrounded by a sac-like or scaly envelope, especially if the gills 

 are white. 



" 3. Avoid fungi having a milky juice, unless the milk is 

 reddish. 



" 4. Avoid fungi in which the cap, or pileus, is thin in propor- 

 tion to the gills, and in which the gills are nearly all of equal 

 length, especially if the pileus is bright colore4. 



" 5. Avoid all tube-bearing fungi in which the flesh changes 

 color when cut or broken or where the mouths of the tubes are 

 reddish, and in the case of other tube-bearing fungi experiment 

 with caution. 



" 6. Fungi which have a sort of spider web or flocculent ring 

 round the upper part of the stalk should in general be avoided. 



" Rules I, 2, and 5 may for the beginner be regarded as abso- 

 lute, with the exception to rule 2, Amanita ccesarea, the gills of 

 which are yellow. Rules 3, 4, and 6 have more numerous excep- 

 tions, but these rules should be followed in all cases, unless the 

 collector is content to experiment first with very small quantities 

 and learn the practical result." 



Economic Uses of Fungi. — A large number of the Fungi, 

 particularly of the Basidiomycetes, are used for food. There 

 are, however, only a few of these which enter the market. These 

 are derived chiefly from Agarictis campestris (Fig. 21, illus. i) 

 and Agaricus arvensis, although some other species of Agaricus 



* Yearbook of United States Department of Agriculture 1897. 



3 



