36 



STUDIES OF AMERICAN FUNGI. 



Still undeveloped, are quite well marked out. Just underneath the 

 pileus layer are the gills, in the section one gill is exposed to view 

 on either side. In the section of the larger button the free edge of 



the gill is still closely applied to the 

 stem, while in the small one the gills 

 are separated a short distance from 

 thestems showing "gill slits." Here, 

 too, the connection of the margin of 

 the pileus with the stem is still shown, 

 and forms the veil. This kind of a 

 veil is a marginal veil. 



The stem is hollow even at this 

 young stage, and a slender cord of 

 mycelium extends down the center of 

 the tube thus formed, as is shown in 

 the sections. 



The plants are nearly all white 

 when full grown. The brown scales, 

 so close together on the buttons, are 

 widely separated except at the top or 

 center of the pileus, wherethey remain 

 close together and form a broad cap. 

 A study of the different stages, 

 which appear from the button stage 

 to the mature plant, reveals the cause 

 of this change in color and the wide 

 separation of the dark brown scales. 

 The threads of the outer layer of the 

 pileus, and especially those in the 

 brown patches seen on the buttons, 

 soon cease to grow, though they are 

 firmly entangled with the inner layers. 

 Now the threads underneath and all 

 through the plant, in the gills and in 

 the upper part of the stem, grow and 

 elongate rapidly. This pulls on the 

 outer layer, tearing it in the first place 

 into small patches, and causing them 

 later to be more widely separated on 

 the mature plant. Some of these 

 scales remain quite large, while others 

 are torn up into quite small tufts. 



FiGUKK 34. — Coprinus comatus 

 (natural size). This one entirely 

 white, none of the scales IMack 

 tipped. 



