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BRACKET FUNGI - CONTINUED Polyporus squamosus (commonly known as "Dryad's Saddle") forms large, thin, polypore brackets up to 50 cm across. Quite often these brackets are produced in clusters on stumps or dying branches of deciduous trees such as elms, beech and sycamore. They cause an intense white-rot of the wood. However, unlike the hard, woody polypores, the brackets of P. squamosus are produced annually (in spring or summer) and last for only a few weeks before they decay and are replaced by a new flush of fruitbodies in the next season. The brackets are relatively thin (about 3 cm) and have a tough, rubbery consistency, with pores on the underside. The tops of the brackets are covered with concentric zones of dark scales. See Figs 1 and 2 below.
Fig 7. Polyporus squamosus brackets about 30 cm wide, growing from the base of a sycamore stump. [© Jim Deacon]
Fig 8. Polyporus squamosus brackets on a decaying sycamore tree. [© Jim Deacon] Coriolus versicolor is another very common species, frequently found on the wood of deciduous trees. The brackets are quite small - usually 5-6 cm across - but are produced in abundance and often occur in multiple layers on decaying wood (Figs. 3-5 below). When first produced, the brackets have a felty upper surface but they lose this with age and become leathery, about 2-3 mm thick. They are concentrically zoned, with different colours ranging from brown to grey, but usually with a white or cream margin. C. versicolor is a variable fungus that causes an intense white rot. It is also notable because it can grow at very low nitrogen levels, and possibly benefits from the growth of associated nitrogen-fixing bacteria.
Fig 9. Coriolus versicolor, the "Many-zoned Polypore" This fungus is one of the most common and important causes of decay of deciduous trees. It causes an intense white rot. [© Jim Deacon]
Fig 10. A dark grey variant of Coriolus versicolor. [© Jim Deacon]
Fig 11. Coriolus versicolor fruitbodies growing out of a bowling pin. [Note: this image has been colour-enhanced because the original image was taken in poor light] [© Jim Deacon]
Fig 12. Ganoderma lucidum fruitbodies growing from a block of compressed sawdust and woodchips. This fungus is rare in Britain, but relatively common in tropical and subtropical regions. For example, it causes a serious root-rot of pine trees in South Africa. The fruitbodies are richly laquered, with shiny black stipes. [© Jim Deacon] |
