istle with spiny hairs. In two or three days
abruptly swollen branches, of a club shape, will make their appearance
on the threads both in the air and in the fluid. Sometimes these
branches are prolonged into an equal number of sporangia-bearing
threads, but most frequently they divide first at their swollen
summits into numerous branches, of which usually one, sometimes two
or three, develop into sporangia-bearing threads, while the rest are
short, pointed, and form a tuft of rootlets. Sometimes these rootlets
reduce themselves to one or more rounded protuberances towards the
base of the sporangia-bearing threads.

[Illustration: FIG. 93.--Zygospores of _Mucor phycomyces_. (Van Tieghem.)]

There are often also a certain number of the branches which had
acquired a clavate shape, and do not erect themselves above the
surface, instead of producing a fertile thread, which would seem to
have been their first intention, become abruptly attenuated, and are
merely prolonged into a mycelial filament. Although in other species
chlamydospores are formed in such places on the mycelium, nothing of
the kind has been traced in this species, more than here indicated.
Occasionally, when germination is arrested prematurely, certain
portions of the hyphae, in which the protoplasm maintains its vitality,
become partitioned off. This may be interpreted as a tendency towards
the formation of chlamydospores, but there is no condensation of
protoplasm, or investiture with a special membrane. Later on this
isolated protoplasm is gradually altered, separating into somewhat
regular ovoid or fusiform granules, which have, to a certain extent,
the appearance of spores in an ascus, but they seem to be incapable of
germination.

Another method of reproduction, not uncommon in _Mucorini_, is
described by Van Tieghem in this species. Conjugating threads on the
substratum by degrees elaborate zygospores, but these, contrary to
the mode in other species, are surrounded by curious branched
processes which emanate from the arcuate cells on either side of the
newly-developed zygospore. This system of reproduction is again
noticed more in detail in the chapter on polymorphism.

M. de Seynes has given the details of his examination of the sporidia
of _Morchella esculenta_ during germination.[O] A number of these
sporidia, placed in water in the morning, presented, at nine o'clock
of the same evening, a sprout from one of the extremities, measuring
half