THE DEVELOPMENT OF CORTINARIUS PHOLIDEUS 525 
broad salient, by branching, forms two salients, each of which there- 
after develops into a lamella in the usual way. This probably illus- 
trates the method of origin of the dichotomous or forked lamellae 
characteristic for Cantharellus and certain species of Russula. 
Figures 35-37 illustrate a condition due to the strongly inrolled 
margin of the pileus. Figure 35 is of a section tangential to the pileus 
margin. In the center a lamella appears with a cavity on either side. 
Figures 36 and 37, respectively, nearer the stem, show the same con- 
dition; the lamellae appear as bars continuous from the upper to the 
lower part of the pileus, with separate cavities between them. The 
gills, however, have not become continuous with the tissue below by 
growing down and uniting with it. This tissue belongs to the hymeno- 
phore of what is morphologically the under surface of the pileus. The 
inrolling of the margin of the latter, however, has reversed the posi- 
tion of the hymenophore. The presence of the salients of secondary 
lamellae on this lower surface serves to make this more clear. The at- 
tachment of the gills below, as well as above, represents their point 
of origin. The sections are not cut perpendicular to these points, but 
are tangential to the "backs" of the lamellae; their direction of growth 
is not in the plane of the section, but at right angles to it. The spaces 
between the lamellae are extensions of the general annular cavity 
nearer the stem. 
The Blematogen 
Before any internal differentiation takes place the young basidio- 
carp is completely enveloped by a universal veil or blematogen. The 
hyphae composing this outer layer are differentiated from the other 
elements of the fruit-body by the fact that their cells are short and 
enlarged, the outer ones being dead, with thick brown walls and 
scanty content. The direction of these hyphae is outward and up- 
ward. They diverge at the ends, forming a loose structure easily 
rubbed off during growth or in the manipulation of the fruit-bodies 
preparatory to study. 
The blematogen has a very striking appearance at about the time 
of the formation of the hymenophore primordium (fig. 10). The 
large hyphae stand straight out from the pileus surface, their clear 
yellow-brown walls, which do not stain at all, contrasting sharply with 
the deeply stained and closely interwoven elements of the pileus. At 
this same time the weft of hyphae between the pileus and blematogen. 
