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AMERICAN JOURNAL OF BOTANY 
[Vol. 9. 
hyphae immediately above. This in turn is followed by another broad, 
densely staining area, and this is succeeded by two other layers also staining 
deeply but not so wide. The significance of these regions is not clear, but 
it appears that by differentiation of the tissue between the couche piUoglne 
and the light-staining tissue above it, the reproductive tissue is formed. 
Figures 64 and 65 show a median longitudinal section of the pilear region 
in which differentiation has set in and a number of poroid gills have been 
formed. The tramal elements shown in the enlargement (fig. 65) take the 
stain heavily, but the palisade cells are too faint to register an impression 
on the photographic plate. Such appearances as this suggest the possible 
origin of the gilled fungi from a poroid type. 
COPRINUS EPHEMERUS AND C. STERCORARIUS 
The young carpophores of Coprinus ephemerus and C. stercorarius 
generally appear at the margin of the agar culture and seem to arise from 
a comparatively stout rhizomorph-like strand of hyphae. Very often a 
small piece of agar containing hyphae of C. ephemerus and C. stercorarius 
transferred to another culture medium produced small greyish sclerotia, as 
shown by Brefeld (1877). Mycelial growth then continues, radiating from 
the inoculum to the margin of the agar where the carpophores are formed. 
Not uncommonly, small carpophores arranged in a radial series arise from 
a rhizomorph close to the sclerotium, as shown in figure 66 (PI. XXXII). 
Subsequently minute carpophores arise all over the agar, as shown in 
figures 67 and 68. Young carpophores were fixed in Flemming's weak 
solution diluted to one quarter strength. The earliest stages in the devel- 
opment of C. ephemerus resemble in the main the stages described for 
C. micaceus (Levine, 1914). The young, undifferentiated button, less than 
.1 mm. in diameter, consists of a very much entangled mass of hyphae. 
The carpophore stains uniformly, although the enveloping outer hyphae 
end in large globose cells having thick walls. These cells very often stain 
heavily with the gentian violet of the triple stain. The primordium of the 
pileus does not stain differentially as readily as does that of C. micaceus, 
and consequently it is not easily recognized at first. The primordium of 
the hymenium, however, takes the stain heavily and is the first structure 
to be noticed in the differentiation of the carpophore. It consists of a 
horizontal series of palisade pockets and appears in the upper third of the 
young button; in longitudinal median section it appears, as it has been 
often described for other species of agarics, as two densely stained areas to 
the right and left of a median vertical line. In C. stercorarius (fig. 85, 
PI. XXXV), the young, undifferentiated carpophore consists of a weft of 
mycelium in which strands of parallel hyphae can be traced for a consider- 
able distance, the entire mass forming a more or less ovoid body and so 
differing from the corresponding stage of C. ephemerus and C. micaceus. 
In this species, also, one may notice that the terminal cells of the hyphae 
