Introduction to Fungi, Third Edition

194 ZYGOMYCOTA
(i.e. striate) wall inside the thin sporangiolum
wall which clings to it and conforms to its shape,
making it difficult to discern that the spore
wall is distinct (Higham & Cole, 1982). The spore
inside the sporangiolum has no appendages.
Choanephora cucurbitarum is heterothallic. Its
zygosporangia develop from intertwined zygophores
and are held in place between tongs-like
suspensors (Kirk, 1977; Chang et al., 1984). The
zygosporangial wall is thin and may flake off
or fracture to reveal the striate wall of the
enclosed zygospore.
Blakeslea
Blakeslea trispora, which has been isolated from
cowpeas, tobacco and cucumber leaves, forms
two kinds of asexual reproductive structure in
culture: nodding columellate or non-columellate
sporangia with brown, faintly striate spores
which usually bear bristle-like appendages, and
non-columellate sporangiola borne in large
numbers on globose vesicles (Fig. 7.27). The
sporangiola contain 2 5 (typically 3) distinctly
striate, dark brown spores which also have
bristle-like appendages. The production of the
Fig 7.27 Blakeslea trispora.
(a) Sporangiophores with globose
terminal vesicles bearing
sporangiola containing three or
four spores. (b) A dehisced
sporangiolum showing two spores
released from it. Note the striate
wall, the polar spore appendages
and the splitting of the
sporangiolum wall into two halves.
(c) Sporangiophore with a drooping
sporangium. No columella was
observed. (d) Dehisced sporangium
also lacking a columella. Note the
split sporangial wall and the
sporangiospores with striate walls
and polar appendages.