46 
GERTRUDE E. DOUGLAS 
to the base of the fruit body, where growth is less active, the tissue 
becomes more and more loose, the hyphae broad (6 ijl), and almost 
unstained. Completely covering the young button is a thin, deeply 
stained layer, made up of large, thick-walled hyphae, in a more or 
less complete state of disorganization. This is evidently not a proto- 
blem, such as is present in Agaricus compestris (3) and probably in 
certain species of Cortinarius (15), but appears to be formed as in the 
case of Mycena suhalcalina by a transformation of the tissue on the out- 
side of the fruit body by substances in the substratum, though which 
it has pushed its way. As the plant grows older, this outer stratum 
of dead elements is exfoliated. 
The Primordia of Pileus, Stipe a?id Hymenophore. — When the fruit 
body has reached the stage of figure 83, a sharp constriction has formed 
below the free end by the branching and epinastic growth of the 
hyphae. As in the preceding species, this groove marks the division 
between the primordia of the stem and pileus. The whole fruit 
body has increased considerably in size, partly on account of the 
spreading out and loosening of the tissue and partly because of the 
addition of new elements. On the top of the pileus fundament the 
ends of the radial fibers break off in small mats or tufts, while just 
beneath the strongly curved margin and extending for a short distance 
down the stem is now distinguishable the primordium of the hymeno- 
phore (figs. 85, 86). This region, contrary to the condition in the 
preceding species, does not take the stain readily. It appears on 
closer examination to be composed of blunt hyphae with a somewhat 
irregular direction, but showing a marked tendency to turn downward 
perpendicularly to the pileus or outward from the stem. 
The Palisade Layer. — These hymenophore elements increase very 
rapidly by branching and at the same time become considerably 
broader, so that a very compact palisade layer results (figs. 85, 86 
and 98). It still is very resistant to the stain, but is easily distinguish- 
able from the looser pileus and stem tissues adjacent to it. 
The Development of the Gills. — The method of development of the 
gill salients is precisely the same as described in the preceding species 
in this paper and in the case of the previously mentioned endogenous 
forms. Figures 87-90 represent serial sections from the youngest 
fruit body which shows traces of these folds. They are protected in 
their development by the strongly inrolled pileus margin, which 
causes the apparent gill cavity in figures 89 and 90. 
i 
