106 MISSOURI BOTANICAL GARDEN. 
small, white patch on the surface. In two or three days, 
sporophores are thrown up from the prostrate mycelium. 
These bear branching hyphae which form terminally by 
abstriction, simple, continuous chains of conidia. This 
portion of the colony is usually gray to blue green in color, 
varying with the medium. The filaments of the mycelium 
in rich agar media often bear swollen cells, resembling 
chlamydospores in shape (pl. 11, f. 2), but which have 
not been observed to form the thicker wall, characteristic 
of such spores. Under the same condition, the mycelium 
becomes fluffy, and many filaments unite together in 
strands, forming Coremium clusters. The filaments ordi- 
narily measure 3u to 4u in diameter, and contain elongated 
cells. On the other hand, the swollen cells are spherical, 
with a diameter of 4y to 8y. 
Upon older cultures, especially upon wood, there are 
formed rounded tufts or clumps of curled and distorted 
hyphae and filaments, which are either lemon-yellow or 
orange-red in color, varying with the acidity or alkalinity of 
the culture medium. The color is due to the secretion of 
a pigment in the form of granules on the surface of the fil- 
ament, evidently by exudation (pl. 11, f. 3). This pig- 
ment is readily soluble in slightly acid or alkaline water, 
-in hot alcohol, and in some other solvents. It is red when 
alkaline and yellow when acid. The fungus, as a rule, 
when grown artificially, overcomes a moderate amount of 
alkalinity by the formation of an acid, and as a result, 
most cultures assume the lemon-yellow color when old. In 
cultures on wood, especially sapwood, the pigment is car- 
ried into the wood cavities by absorption, thus staining the 
wood. The color, although bright at first, fades as the 
culture grows old and dries out. 
CONIDIA. 
The conidia are borne on conidiophores which vary in 
length from 1004 to 5004, with a diameter of 3p, or slight- 
