Introduction to Fungi, Third Edition

210 ZYGOMYCOTA
Fig 7.39 Conidiobolus
coronatus. (a) Conidiophore
with attached primary
conidium. Note the columella
which protrudes into the body
of the conidium. (b) Apex of
conidiophore and conidium
after discharge by eversion of
the columella from inside the
spore. (c) Primary conidium
germinating by repetition to
produce a secondary conidium
of similar type. (d) Conidium
germinating directly, forming
several germ tubes.
(e) Conidium germinating to
produce a villose secondary
conidium. (f) Conidia
germinating to produce
numerous secondary
microconidia which are
discharged by columellar
eversion.
maturity each microconidium is supported on a
two-ply columella and projected by the eversion
mechanism. In older cultures, primary conidia
may form short conidiophores terminating in
pear-shaped spiny-walled (villose) conidia, which
are also projected by columellar eversion. The
precise conditions under which spiny conidia are
formed are not known. They have been interpreted
as resting spores, and they germinate to
form a coarse septate mycelium. The possession of
both microconidia and villose conidia is a
combination unique to C. coronatus. Another
type of resting spore may develop from ungerminated
primary conidia which swell and form 2 3