THE LAMELLAE IN COPRINUS MICACEUS 
349 
stercorarius and rests on the surface of a compact layer of hyphae 
which covers the agar. The mycehal layer covering the agar consists 
of a dense plectenchyma of septate hyphae, the walls of which are 
gelatinous and stain heavily. The hyphae in contact with the agar 
are abundantly branched and extend down into it forming a very 
loose network. These hyphae have thin cell walls and a fine granular 
protoplasm with nuclei easily differentiated in staining. The ap- 
pearance of these young buttons suggests that they originate by the 
upgrowth of numerous hyphae from the mycelium covering the agar. 
That portion of the core of the button nearest the substratum is very 
compact and the hyphae here appear to be more abundantly branched. 
The upper portion of the button consists of a loose, well aerated 
structure of more or less intertwined hyphae. The hemispherical 
pads, shown by Strasburger (1884) as marking the presence of the 
so-called protoplasmic pit connections between hyphal cells are con- 
spicuous. The nuclei in all of these cells are well differentiated by 
Flemming's triple stain. The nucleoles are ruby red while the chro- 
matin is blue. 
The surface of the button consists of a fairly well marked zone of 
rather straight radial hyphae which arise from the outer cells of the 
mass. Near the substratum these radial hyphae are short and almost 
horizontal, at the apex of the button they are vertical. These hyphae 
branch and make a rather uniform peripheral layer over the central 
region. Each hyphal filament (fig. 2) in the layer is about six to 
eight cells long and one or two of the outer or terminal cells are slightly 
larger and spherical or oval in shape and their walls are thick and 
gelatinous. Bref eld's (1877) account of the peripheral layer of the 
young carpophore of Coprinus stercorarius applies perfectly to that of 
Coprinus micaceus. 
PiLEUS PrIMORDIUM 
A little above the central region of the button and just below the 
peripheral layer an accelerated growth of intertwining hyphae results 
in the formation of a denser mass which is the beginning of the pileus. 
The hyphae forming this mass are narrow, much branched and with 
dense easily stained cytoplasm. This pileus primordium can be dis- 
tinguished before the sections are stained by its density as contrasted 
with the looser middle portion below and the thick walled cells of the 
peripheral layers. It is very small at first but apparently by the rapid 
growth and branching of its hyphae it broadens out and soon suggests 
