350 MICHAEL LEVINE 
the outlines of the future cap {fig. 3) as shown by Fayod (1889) in a, 
number of agarics. Its development is very regular and results in a 
hemispherical mass of compact narrow interwoven hyphae. At the 
same time there is a vertical elongation of the carpophore primordium. 
In the region immediately below the young pileus this vertical growth 
leads to the formation of parallel strands of hyphae which become the 
stipe. The cells of the hyphae in this portion of the carpophore appear 
to have grown especially in their vertical diameters. Their cytoplasm 
is not dense but is evenly distributed and stains very faintly in com- 
parison with that of the hyphae in the young pileus. In the basal 
portion of the young carpophore the hyphae are more or less twisted 
upon each other and their cells are much shorter. Their cytoplasm 
is somewhat denser and the nuclei can be more easily differentiated. 
Figure 6 shows the appearance of the hyphae whicfi lie in the mycelium 
and in the lower portion of the carpophore. These cells are long, 
and their walls are thick and gelatinous. Their cytoplasm contains 
large and irregularly scattered vacuoles. The nuclei show clear ruby 
stained nucleoles and finely granular chromatin. The formation of 
the hemispherical pileus primordium as Fayod has pointed out divides 
the young carpophore into three distinct regions, the peripheral layer, 
the' pileus primordium and the tissue which will subsequently form 
the stipe. 
The Hymenium 
In a slightly older stage we find the beginning of the differentiation 
of the hymenium. The development of the hymenial elements seems 
to begin at or near the lower surface of the densely interwoven mass 
of hyphae which is to develop into the pileus. The whole carpophore 
is still oval in outline. There is as yet no indication of narrowing to 
form a stipe. In vertical section the first indication of the developing 
gills consists of two dense areas symmetrically placed to the right and 
left above the center of the carpophore as has been so frequently shown 
in recent papers. They are distinctly endogenous in origin and lie 
about one quarter of the distance from the surface to the center of the 
carpophore. Careful study shows that the hyphal cells in these 
regions are forming downwardly arched ridges of densely staining 
palisade cells. These palisade cells it may be noted arise in quite a 
different fashion than that described by Fischer (1909) for Armil- 
laria mucida Schrad. and Beer (191 1) for Clitocyhe laccatus. These 
authors hold that the hymenium is formed by an inward exten- 
