THE DEVELOPMENT OF CORTINARIUS PHOLIDEUS 529 
7. The lamellae originate as downward-growing folds of the level 
palisade zone, through. the influence of lateral pressure in the palisade, 
and, more particularly, by downward growth of hyphae from the hy- 
menophore in radial, regularly spaced areas. Their differentiation is 
centrifugal, from the stem toward the pileus margin. The first folds 
or ridges in the hymenophore are the salients of the lamellae them- 
selves. The gill trama is formed by the downward growth of hyphae 
from the hymenophore into the gill salient, and increases by inter- 
stitial growth. 
8. The cortina is the silky veil stretching over the gills, attached on 
the one hand to the surface of the pileus margin and on the other to 
the stem. It is composed of the hyphae of the inner layer of the blema- 
togen, together with fragments of the ground tissue below the hymeno- 
phore. It is covered externally by remnants of the outer layer of the 
blematogen, as indicated by the dark patches that may be attached to 
its outer surface. 
Botanical Department, 
Cornell University. 
LITERATURE CITED 
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