Fig. 68. Mucor, habit and detail of sporangium before and after dehiscence.
Fig. 69. Rhizopus, habit.
Fig. 70. Thamnidium elegans, habit and detail of sporangioles.
Fig. 71. Absidia, habit.
Fig. 72. Mortierella, habit and sporangiophore tip after sporangial dehiscence.
Fig. 73. Helicostylum, sporangioles.
Fig. 74. Chaetocladium, sporangioles.
Fig. 75. Pilaira, sporangiophores before and after elongation, and sporangium.
Fig. 76. Pilobolus, sporangiophore.
Fig. 77. Syncephalis, habit, sporangiophore and merosporangia.
Fig. 78. Piptocephalis, habit and detail of final branch with head cell and merosporangia.
Fig. 79. Oedocephalum, habit and sporing head.
Fig. 80. Rhopalomyces, sporing head.
Fig. 81. Syncephalastrum, habit and detail of merosporangium.
Fig. 82. Coemansia, habit, sporoclade with sporangia and sporangium with spore inside.
Fig. 83. Kickxella, habit and sporoclade.
Fig. 84. Cunninghamella, habit and fertile head.
Fig. 85. Mycotypha (l) and Ostracoderma (r) conidiophores.
Fig. 86. Ballocephala, habit of sporangiophores growing from parasitised tardigrade, sporangiophore and sporangia.
9(6) | Sporangia often with pigmented walls, yellowish when young, finally grey or black, with well marked columella left after spore dispersal. Individual sporangiophores observable with unaided eye, up to 20mm long. | |||||||||||||
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(N.B. Zygorhynchus would key out with Mucor. It is more often isolated from soil, and is distinguished from Mucor by the presence of zygospores with unequal suspensors) | ||||||||||||||
- | Sporangia white, without a columella, readily becoming a spore droplet. Sporangiophores delicate, often only 200-400µm long. Fine, white, garlic-smelling mycelium often present. | |||||||||||||
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10(5) | Sporangioles formed at the final tips of a densely dichotomous system of branchlets, originating some distance below a terminal sporangium (which may be absent in young specimens). Sporangioles up to 25µm diam., with up to 6 spores. Spores 8-12 × 6-8µm. | |||||||||||||
Thamnidium elegans (fig. 70) | ||||||||||||||
- | Sporangioles either at the curved tips of slender branches, or clustered in groups about halfway along tapering branches which radiate from the sporangiophore below the sporangium; the branch tips of the latter give the fertile portion of the sporangiophore a bristly appearance. | |||||||||||||
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11(1) | Spores formed in chains. | 12 | ||||||||||||
- | Spores formed singly. | 14 |
12(11) | Sporangiophores regularly and repeatedly dichotomously branched. Chains of 2-10 spores produced in small groups, which may be wet or dry, on deciduous heads, 4-15µm diam. Parasitic on other fungi, mostly other Mucorales. | |||||||||||||||||||
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- | Sporangiophores simple or irregularly branched. | 13 | ||||||||||||||||||
13(12) | A large conspicuous fungus, macroscopically Mucor-like, mycelium coarse. Sporangiophores with a distinct terminal swelling with crowded spore chains. Spores usually 5-10 in a chain, globose to ovoid, 2-8 × 4-6µm. | |||||||||||||||||||
Syncephalastrum racemosum (fig. 81) | ||||||||||||||||||||
- | Sporangiophores less conspicuous, 100-1000µm high, with a 'holdfast' at the base attaching the sporangiophore to the substrate. Mycelium very fine. Parasitic on other Mucorales. | |||||||||||||||||||
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(N.B. Oedocephalum spp. (fig. 79), the anamorphic states of many dung fungi (esp. Ascobolaceae and Pezizaceae), Rhopalomyces (fig. 80), and some Aspergillus spp. are superficially similar to Syncephalis at first sight). | ||||||||||||||||||||
14(11) | Sporangia containing a single closely fitting elongated spore, produced in serried ranks on one side of a boat-shaped branch (sporoclade). | 15 | ||||||||||||||||||
- | Single-spored sporangia ('spores') globose, produced singly or if in groups not on sporoclades. | 16 |
15(14) | Sporoclades lateral. Sporangiophores usually yellowish. (No parasitism has been demonstrated, but in culture grows much better in the presence of the white, garlic-smelling Mortierella spp.). | ||||||||||
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- | Sporoclades produced in a terminal verticil. Sporangiophores shining white. | ||||||||||
Kickxella alabastrina (fig. 83) | |||||||||||
16(14) | Spores produced in clusters below the apex of the final branches of a compound, often trifid, branching system which is given a bristly appearance by the projecting tips. Superficially similar to Thamnidium or Helicostylum. Capable of parasitising, and growing much better in association with, other Mucorales. | ||||||||||
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- | 'Spores' not produced in subterminal clusters, but terminally on lateral vesicles, or over the surface of swollen fertile regions of the sporangiophore. | 17 | |||||||||
17(16) | Sporangiophores up to 250µm high. Lateral vesicles numerous, each producing a single 'spore', which is projected when mature. Parasitic on tardigiades. | ||||||||||
Ballocephala (fig. 86) | |||||||||||
- | Sporangiophores visible with the unaided eye. Spores produced on swollen parts of the sporangiophore. | 18 | |||||||||
18(17) | Sporangiophores branched, with more or less globose terminal fertile regions. Spores dry and powdery, yellowish or pinkish in mass. | ||||||||||
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- | Sporangiophores unbranched, fertile portion 200-300 × 15-20µm. Fertile region terminal only, cylindrical. Spores smooth, greyish in mass, 2-4µm diam. | ||||||||||
Mycotypha microspora (fig. 85) | |||||||||||
(N.B. Ostracoderma epigea (fig. 85), the anamorph of Peziza astracoderma, which occurs on paper and sometimes dung and highly organic substrates, was originally described as Mycotypha dichotoma. The fertile regions are cylindrical but multiple as the result of several close dichotomous divisions at the base of the fertile portion). |
Notes
There are few reports of Ascozonus, apart from A. woolhopensis. Observed spore sizes of A. woolhopensis suggest that measurement of Renny's (1874) illustrations of spores leads to values which are too large (19-20 × 6-6.5µm). Those in parentheses are what they might be, based on the discrepancy between observed values for A. woolhopensis and Renny's illustration.