LYMAN: STUDIES OF HYMENOMYCETES. 
175 
but become more and more thickly disposed as the production in¬ 
creases. 
Development of conidia .— The several conidia composing one group 
are formed successively in the following manner (pi. 20, fig. 68 a-f): 
a papilla appears on the hypha, and elongates into a tubular projec¬ 
tion which later becomes club-shaped at the extremity. The tubular 
base forms the sterigma, while the enlarged terminal portion develops 
into the spore by continued elongation. As the spore enlarges it 
becomes curved into an allantoid form, and is finally cut off from the 
sterigma by a septum. As the first spore approaches mature size, a 
second sterigma appears at the base of the first, or sometimes from 
its side, and a second spore is formed, to be followed by others succes¬ 
sively. Thus there is rapidly formed a group or tuft of from two to 
many spores, each being borne on a short sterigma, while all are car¬ 
ried on a common elevation from the side of the parent hypha. This 
elevation or conidiophore may be low and dome-shaped, capitate, or 
irregularly shaped (pi. 20, fig. 63-66, 69). In case the mycelium 
bears clamps, the conidiophore frequently arises from the convex 
surface of a clamp connection (pi. 20, fig. 69). Figure 62 (pi. 20) 
represents a young mycelium which has begun the formation of coni¬ 
dia, and in which the majority of the conidiophores have as yet pro¬ 
duced but one spore. One hypha from such a young mycelium 
showing various stages in the development of conidia is shown in 
figure 67 (pi. 20) on a somewhat larger scale. 
The conidia seldom grow submerged in the substratum, but develop 
on aerial hyphae, and especially on those which lie on or just beneath 
the surface; in the latter case the spores project away from the sub¬ 
stratum into the air. Hence it frequently occurs that the conidia are 
all situated on the same side of the hypha (pi. 20, fig. 69). The most 
copious production of conidia is on those hyphae which have spread 
over the moist surface of the cover glass beyond the limits of the hang¬ 
ing drop. If a young conidium becomes submerged before it reaches 
maturity, its development as a spore is frequently arrested, and it 
grows into a vegetative branch. 
Germination of conidia .— During germination the behavior of the 
conidium agrees very closely with that of the basidiospore. It swells 
to twice the original diameter, and two or more guttulae appear which 
were frequently not visible before (pi. 20, fig. 71-73). The mycelium 
also is in no way to be distinguished from that arising from a basidio- 
