300 



STUDIES OF AMERICAN FUNGI. 



growth. The convex pileus usually becomes plane or expanded as it 

 grows. If the convexity is greater it is said to be campanulate (Fig. 

 245), conical hemispherical, etc., terms which need no explanation. 

 The pileus is umhilicate when it has an abrupt, sharp depression at 

 the center (Fig. 241), infundibuliform when the margin is much 

 higher than the center, so that the cap resembles a funnel (Fig. 244), 



Figure 241. Figure 242. Figure 243. 



FlciURE 241. Omphalia campanella, pileus umbilicate, gills decurrent. 

 Figure 242. Lepiota procera, pileus convex, umbonate ; annulus free, movable; 



gills free. 

 Figure 243. Agaricus campestris, pileus convex, gills free. 



and depressed when the center is less, or irregularly, sunken. When 

 the center of the pileus is raised in the form of a boss or knob it is 

 umbonate (Fig. 242). The umbo may have the form of a sharp ele- 

 vation at the center, or it may be rounded or obtuse, occupying a 

 larger part of the disc. When it is irregular or indistinct the pileus 

 is said to be gibbous (Fig. 246). 



The gills. The gills or lamellce are thin blades on the under side 



