330 
GERTRUDE E. DOUGLAS 
CORTINARIUS LILACINUS 
(Figs. 51-62) 
The sub-genus Inoloma, to which C. lilacinus belongs, is charac- 
terized by the presence of a large bulbous base to the stem, a feature 
which in some species becomes extremely well developed. Before 
there is any external sign of differentiation, a good-sized tubercle is 
formed (4X5 mm.), within which certain changes are taking place. 
Figure 51 represents a median section of such a tubercle. The tissue 
is very nearly homogeneous in character, with the exception of a 
somewhat more dense, deeply staining region within, broadly conical 
in form, the primordium of the stem. The next later stage (figs. 52, 
53) exhibits a considerable advancement in development. The whole 
of the lower part of the tubercle has become very dense and compact. 
Above, the hemispherical pileus primordium is marked off from that 
of the stem by the deeply staining hymenophore fundament. The 
fibers in the pileus region are similar to those in the stem, are very 
closely massed together and assume a generally radial arrangement. 
At the margin, however, they turn strongly downward and here form 
the hymenophore primordium (figs. 52, 61). Extending over the 
surface of the pileus and to the sides of the tubercle, is the blematogen, 
a still rather indefinite region (fig. 52). The gills are formed in the 
manner described for the other species. An annular cavity appears 
at about the time of, or just prior to, the formation of the palisade 
layer (figs. 56, 57), which is very quickly followed by the formation 
of the young gills. The palisade cells take the stain less easily than 
the subadjacent tissue and thus the subadjacent region stands out 
in sharp contrast. As in C. anfractus, the latter represents a new 
area of active growth. It remains as a thin stratum between the gills 
but when it reaches them, it curves downward and growing very 
actively forms the greater part of the trama. 
On the surface of the fruit body, no definite cortex is formed. 
Although the pileus and the blematogen becomes consolidated, in 
the older stages the boundary between the two regions becomes very 
distinct, owing to the difference in the character of the tissues (fig. 62). 
The outer layers appear to rub off, as the plant pushes up through the 
soil, so that a duplex character to the veil is here not apparent. The 
cortina is made up of the blematogen and the partial veil, to which 
new elements are added by marginal pileus growth. Practically no 
