230 
A. W. BLIZZARD 
on the under surface of the pileus as shown in Figure 80. In this 
figure, on each side of the sahents, a portion of the paHsade layer is 
shown. Since these structures develop centrifugally the first differen- 
tiation occurs on or near the stipe. Consequently in a tangential 
section the portion to the right or left would be cut obliquely and show 
tissue nearer the margin than that in the center of the section. Thus, 
the palisade layer represents a younger portion of the hymenophore, 
in which salients have not as yet made their appearance. 
The development of the lamellae in width is as has been described 
for the previous species. The subadjacent hyphae by elongation, 
aid in the extension of the salients in width or keep pace with their 
growth. New elements are also added by intercalary growth to the 
palisade layer. Figures 85-89 show in detail the development of a 
gill from the palisade stage of the hymenophore through the first 
evidence of a gill salient to a well-formed lamella. 
Origin of Secondary Lamellae. — As was described for the previous 
species, the salients of the secondary gills appear between the primary 
lamellae on the under surface of the pileus. Those that appear first 
occur near the stem (Fig. 81). Their development is exactly as de- 
scribed for the primary gills. They serve to occupy the spaces 
produced by the divergence of the primary gills as they proceed from 
the stipe. 
Structure of Pileus and Stipe. — The more mature pileus is expanded 
and the hyphae arrange themselves in a radial horizontal direction. 
The trama is composed of hyphal threads that ramify and interlace 
among themselves. The stipe increases in width by branching and 
interstitial growth of the hyphae. In the more mature pileus and 
stem, growth is chiefly by the increase in size of the cellular elements. 
Clitopilus noveboracensis Peck 
Basidiocarp and Stipe Primordia. — The fruit bodies representing 
the primordial stage of the basidiocarp become comparatively large, 
.6 mm. in width and 2 mm. in length, before differentiation of the 
pileus occurs. They are elongate bodies which taper gradually to a 
point at the apex (Fig. 48). The young basidiocarp presents a closely 
interwoven structure composed of slender hyphae averaging about 3^1 
in diameter at the base; toward the apex they are not so stout. The 
general direction of the hyphae is parallel with the direction of the 
growth of the fruit body (Fig. 64). The whole extent of the apical 
