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PROFILES OF FUNGI: ASCOMYCOTA - THE CUP FUNGI AND SPORE-SHOOTERS The Ascomycota is the single largest group of fungi, but most of its members are microscopic or contribute to lichen symbioses (Chapter 13) and are discussed elsewhere in this book. Here we will focus on some of the common, larger saprotrophic species, including those often found on decaying wood. These fungi are quite diverse in morphology, ranging from brittle, saucer-shaped fruiting bodies of 2-3 cm diameter, to gelatinous masses or stag-horn structures. Some resemble members of the Basidiomycota, and the only way to distinguish them is to look for the asci and ascospores under a microscope. One such fungus is Neobulgaria pura (Figs 1 and 2) which has a rubbery, gelatinous consistency and is quite commonly found on fallen logs of beech trees from early summer to early winter in damp woodland habitats. In the immature stage (Fig. 1) the margin of the fruitbody is inrolled, but then the fruitbody expands into a funnel shape (Fig. 2).
Fig. 1. Immature stage of Neobulgaria pura, with inrolled margins.
Fig. 2. Fruitbodies of Neobulgaria pura (or a similar species) in its expanded, funnel-shaped stage, about 2 - 3 cm diameter. Ascospores are released from the upper surface of the mature fruitbody. Another gelatinous species, often found growing on rotting beech logs is Ascocoryne sarcoides (Fig. 3). This fungus produces large numbers of purple- to red-coloured fruitbodies, less than 1 cm high. They are convoluted or turban-shaped and follow the grain of the wood.
Fig. 3. Cluster of purple-coloured fruitbodies of Ascocoryne sarcoides (Ascomycota) growing on a rotting beech log. Each of the convoluted or turban-like fruitbodies is less than 1 cm high. Another fungus commonly found on decaying beech logs is Hypoxylon fragiforme (Figs 4 and 5). It produces large numbers of hemispherical fruiting bodies, each about 1 cm diameter. The fruitbodies are initially salmon-pink in colour, but darken to brick red as they mature and finally blacken.
Fig. 4. Part of a large cluster of fruitbodies of Hypoxylon fragiforme at the brick-red stage on a rotting beech branch.
Fig. 5. Hypoxylon fragiforme fruitbodies ranging from 0.2 to 1 cm diameter on a beech log. Ascospores are released from the surface of the mature fruitbodies. Nectria cinnabarina, commonly known as the "Coral Spot Fungus", is another common species, often seen as cinnabar-red or salmon-pink coloured pustules on fallen twigs (Figs 6 and 7). This fungus can produce either perithecia, which release ascospores, or conidia.
Fig. 6. Pustules of Nectria cinnabarina growing on a wet, fallen twig (the twig is 2 cm diameter).
Fig. 7. Dried pustules of Nectria cinnabarina, the Coral spot fungus, shown at about twice life size. |
