8 



STUDIES OF AMERICAN FUNGI. 



FIGURE 7. Agaricus campestris. Plant in 

 natural position just after rupture of veil, 

 showing tendency to double annulus on the 

 stem. Portions of the veil also dripping 

 from margin of pileus. (Natural size.) 



tured, and in Fig. 6 the veil 

 has just been torn apart. 

 The veil of the common 

 mushroom is very delicate 

 and fragile, as the illustra- 

 tion shows, and when it is 

 ruptured it often breaks 

 irregularly, sometimes por- 

 tions of it clinging to the 

 margin of the cap and por- 

 tions clinging to the stem, 

 or all of it may cling to the 

 cap at times ; but usually 

 most of it remains clinging 

 for a short while on the 

 stem. Here it forms the 

 annulus or ring. 



The Color of the Gills. The 

 color of the gills of the com- 

 mon mushroom varies in 



different stages of development. When very young the gills are 



white. But very soon the gills become pink in color, and during 



the button stage if the veil is broken this pink color is usually 



present unless the button is 



very small. The pink color 



soon changes to dark brown 



after the veil becomes 



ruptured, and when the 



plants are quite old they 



are nearly black. This 



dark color of the gills is due 



to the dark color of the 



spores, which are formed 



in such great numbers on 

 the surface of the gills. 

 Structure of a Gill. In 



Fig. 8 is shown a portion 

 of a section across one of 

 the gills, and it is easy to 



FIGURE 8. Agaricus campestris. Section of 



See in what manner the gill showing /V = trama; j// = subhymeni- 



Spores are borne. The gill um; 4=basidium the basidia make up 



the hymemum ; .r/=stengma ; ^=spore. 



is made up, as the illustra- (Magnified.) 



