238 
Mycologia 
A little later, slight anastomosing elevations of the hymenial 
primordium appear. These are formed by a differential down- 
ward growth of the hyphae in these regions (Fig. 8). As the 
hyphae forming these elevations grow downward, they turn out 
horizontally on both sides to form the hymenium in the pores. 
The hymenium stains deeply while the central part or trama takes 
comparatively little stain. The trama is a pseudoparenchymous 
tissue. After it has grown down for some distance, the trama 
begins to broaden by a diametrical growth of the hyphae, which 
also become loosely associated. For this last reason, the pores of 
the mature carpophores can be easily torn apart or separated from 
the trama of the pileus. The subhymenium appears later, made 
up of an interwoven mass of hyphae tightly crowded together. 
The number of basidia is increased by the branching of the hyphae 
at the clamp connections in the subhymenium. The hymenium 
lines the pores only. The mouths of the pores are sterile. Fig- 
ures 9 and io show vertical and transverse sections of the pores, 
respectively. 
To sum up the development of the carpophore of Ceriomyces 
Zelleri Murrill, there is a homogenous mass of tissue which is 
differentiated simultaneously into pileus and stipe by a cleavage 
plane which gives rise to an annular furrow. The hymenium is 
formed in the roof of this furrow and is exogenous in its origin. 
Ceriomyces Zelleri is gymnocarpic because there is no marginal 
veil. 
University of Washington, 
Seattle, Washington. 
Explanation of Plates CXL and CXLI 
Photomicrographs by Homer O. Blair 
Figure i. A small undifferentiated carpophore of Ceriomyces Zelleri. 
X 30. 
Figure 2. The first differentiation in the carpophore, showing deeply stain- 
ing ring in the periphery. X 20. 
Figure 3. A portion of the palisaded cortex of an older pileus with the ex- 
current hyphie tufted. X 250. 
Figures 4, 5. The cleavage plane in different stages of cleavage. X 12.5. 
Figure 6. A portion of the cleavage plane shown in figure 5 much enlarged. 
X 230. 
