228 
A. W. BLIZZARD 
same thread and slightly larger, which tends to give a clavate appear- 
ance to the threads. The cells are rich in protoplasm and present an 
appearance of active growth. 
Hymenophore Primordmm. — The lamellae make their first appear- 
ance as folds of the level palisade layer. These folds are the rudiments 
of the lamellae themselves. They appear on the surface at or near the 
apex of the stipe, Figure 36, and by progressive growth extend out 
and upward on what is the morphological underside of the pileus. By 
downward growth of hyphae subadjacent to these folds, the trama of 
the lamellae is formed (Figs. 45-46). These tramal threads are dif- 
ferentiated from the other elements of the hymenophore by the fact 
that they do not stain so deeply. These threads branch and furnish 
new elements by which the lamellae grow in thickness and at the same 
time by apical and intercalary growth the lamellae increase in width 
(Fig. 47); 
The tissue of the pileus and stipe subadjacent to the hymenophore 
is peculiar because of extraordinary large interhyphal spaces, due to 
the extension exerted by the pressure from interstitial growth and 
enlargement of the elements of the hymenophore. 
The lamellae develop in length in a radial centrifugal direction, 
following that of the palisade layer. They are decurrent from the 
beginning, since the hymenophore has formed around the upper lateral 
surface of the stipe (Figs. 36-40). At the base of the older ones, 
other lamellae sometimes branch ofl", developing in a manner described 
for the primary gills (Fig. 37). These form the forked lamellae some- 
times present in this species. Secondary lamellae also arise between 
the diverging primary gills, filling the spaces between them. 
Clitocybe cerussata Fries 
Basidiocarp and Stipe Primordia. — The youngest basidiocarps of 
this species which were collected measure .5 mm. in diameter and 
2 mm. in length (Fig. 70). They are composed of slender intei lacing 
hyphae, measuring 3.a in diameter, which form a close interwoven 
tissue. Their general direction is longitudinal, converging at the 
apex (Fig. 83). This homogeneous structure is the primordium of 
basidiocarp and stipe. 
By continued growth of this primordial tissue the stipe fundament 
is finally difTerentiated by the formation of the pileus primordium which 
is marked ofif by the divergence of the apical hyphae. As the stipe 
