LYMAN: STUDIES OF HYMENOMYCETES. 
179 
The first appearance of the conidiophore is a hypha of large size, 
with dense, refractive contents, which usually grows away from the 
substratum into the air, although in liquid media it is not infrequently 
submerged; this hypha becomes capitate by a terminal enlargement. 
When the capitulum has attained about three quarters the mature size, 
the sterigmata appear as minute papillae which rapidly elongate into 
tubular projections. Each sterigma becomes capitate and develops a 
spore at its apex, by whose enlargement the sterigma is reduced to 
about two thirds the original length. This entire process from the 
first appearance of the sterigmata to the full development of the 
spores requires from one and one half to two hours. Successive 
stages in the process are shown in figures 87 to 91 (pi. 21). 
Branching and 'proliferation of conidiopliores. — The older vege¬ 
tative hyphae in drop cultures soon lose their cell contents; but many 
of the conidiopliores remain filled with dense, refractive protoplasm 
even after spore formation is complete. This protoplasm may be very 
limited in extent, being confined to the capitulum and to the part of 
the conidiophore immediately below it (pi. 21, fig. 95), but yet it is the 
center of active, vigorous growth; on account of it, the conidiophore 
branches and rebranches repeatedly, the branches occasionally grow¬ 
ing into vegetative hyphae of considerable length, but usually soon 
producing secondary capitula. Moreover, proliferations through the 
capitulum occur which at once produce secondary capitula in almost 
all cases, and these proliferate in turn, thus forming Arthrobotrytis- 
like fructifications (pi. 21, fig. 92-95; pi. 22, fig. 96-97). The results 
of such growth are very striking in old drop cultures, for although the 
vegetative mycelium may have nearly or quite lost its protoplasm so 
that the empty hypha walls are barely visible, these points of vigorous 
growth are very prominent in the form of complex, tree-like systems 
which may have arisen through repeated branching and proliferation 
of a single conidiophore. Proliferation appears to be a perfectly 
normal process, since it occurs in all cultures, although its greatest 
development is seen in rather attenuated decoctions where the vege¬ 
tative growth is less luxuriant. 
The similarity existing between this imperfect form of Corticium 
effuscatum and that which Brefeld discovered in Polyporus annosus 
has already been referred to. The writer has been so fortunate as to 
secure fresh material of Polyporus annosus and has grown it in pure 
cultures, confirming in all essential particulars the observations of 
Brefeld. The most apparent differences between these conidia and 
