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MORE IMAGES FROM CHAPTER
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Fig 10.8 Diagrammatic representation of some coprophilous fungi. (a) Pilaira anomala (Zygomycota): the sporangiophore elongates to several centimetres at maturity and the spores ‘flop’ onto the surrounding vegetation. (b) Mucor racemosus (Zygomycota) with no special method of spore release. (c) Pilobolus (Zygomycota); see also (h) and (i). (d) Ascobolus sp. (Ascomycota); the tips of the mature asci project from the apothecium and are phototropic, shooting the ascospores towards a light source. (e) Sordaria sp. (Ascomycota); the neck of the perithecium is phototropic and the mature asci elongate up the neck to discharge the ascospores. (f) Coprinus sp. (Basidiomycota). (g) Sphaerobolus sp. (Basidiomycota); the large spore mass is shot from the cup-shaped fruitbody when the layers of this separate and the inner layer suddenly inverts. (h, i) Pilobolus, showing how the terminal vesicle of the sporangiophore acts as a lens to focus light and orientate the sporangiophore, and showing also the mechanism of sporangium discharge (see also Fig. 10.7). [© Jim Deacon]
Fig 10.9a Dutch elm disease caused by Ophiostoma ulmi and O. novo-ulmi. The image shows two mature trees in late spring. Both trees are dying from a heavy infection by fungus. [© Jim Deacon]
Fig 10.9b. The same two trees as in Figure 10.9a, but photographed 3 months later. The trees are nearly dead and were felled later in the growing season. [© Jim Deacon]
Fig 10.9c Underside of the bark of a dead elm tree, showing (arrowhead) the hole where an adult female bark tunnelled into the bark and deposited eggs along the length of the tunnel. When the eggs hatched the new beetle larvae produced radiating galleries, which increased in size as the larvae grew. [© Jim Deacon]
Fig 10.9c: Section of a branch from a dying elm tree, showing a ring of blocked, discoloured xylem vessels from a non-lethal attack in a previous growth season. [© Jim Deacon]
Fig 10.10 Dutch elm disease. (a) Diagram of an intact coremium. (b) Sexual stage of Ophiostoma – a long-necked cleistothecium (closed fruitbody) containing oval asci each containing 8 ascospores. The asci break down at maturity and the ascospores are extruded in mulicage at the tip. (c, d) Beetle brood gallery in the inner bark of a diseased tree. The adult female beetle deposits eggs along the gallery, then the emerging beetle larvae eat out a series of lateral galleries ending in chambers. The fungus sporulates in these chambers and contaminates the beetles that emerge in spring. [© Jim Deacon]
Fig. 10.11. Appendaged spores of estuarine and marine environments. (a) Ascospore of Pleospora with mucilaginous appendages (stippled), about 400 µm. (b) Ascospore of Halosphaeria with chitinous wall appendages (25 µm). (c) Conidium of Zalerion (25 µm). (d) Ascospore of Corollospora with membraneous appendages (70 µm). (e) Ascospore of Lulworthia with terminal mucilaginous pouches (60 µm). (f) Ascospore of Ceriosporiopsis with mucilaginous appendages (stippled) (40 µm). [© Jim Deacon] |
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