340 



pileus (pi) resting on a central stalk ; underneath the cap 

 appears a series of thin radiating plates whicli are known as 

 the lameUce or gills; part way down the stem appears a 

 shreddy membranous ring called the annulus ; this ring {an) 

 is orignally in the form of a veil which extends from the 

 stem to the margin of the pileus so as to completely cover 

 up the gills ; as the pileus grows larger the veil breaks 

 away trom the edge of the pileus and remains in the form 

 of a more or less complete ring about the stem. These 

 parts are shown in Figure 1 which illustrates this species. 



Fig. 1 Agaricus campestris ; Edible; showing mycelium {my) 

 constituting the underground growing portion of the plant; the 

 annulus (an); and the pileus or cap (pi) being turned toward 

 us does not show the gills or lamellae beneath. The line a a repre- 

 sents the surface of the ground. Color of pileus white or grayish. 

 About % natural size of ordinary specimens, though the size varies 

 grea ly ; the stem also is often very short. 



The common field agaric has a normally white pileus 

 though this may be more or less varied with grayish flecks 

 or spots. It can be readily distinguished by the four fol- 

 lowing marks, all of which should be present to be certain 

 of the species, though the first two will separate it from . 

 all the deleterious forms that might be confused with it : 



