Armillaria mellea (Vahl. ex Fr.) Kummer syn. Clitocybe mellea (Vahl. ex Fr.) Ricken Hallimasch, Armillaire couleur de miel, Tęte de meduse, Honey Fungus or Boot-lace Fungus Cap 3–12cm across, very variable, convex then flattened and centrally depressed or wavy, yellow ochre, tawny, to dark brown, often with an olivaceous tinge, covered in darker fibrillose scales especially at the centre. Stem 60–150×5–15mm, often tapering towards the base, yellowish becoming reddish-brown at the base, initially with a thick whitish to yellow cottony ring. Flesh white. Taste astringent, smell strong. Gills white at first then yellowish becoming pinkish-brown and often darker spotted with age. Spore print pale cream. Spores elliptic, 8–9 x 5–6µ. Habitat in dense clusters on or around trunks or stumps of deciduous and coniferous trees and Hazel. Season summer to early winter. Very common. Edible when cooked but should only be eaten in small amounts as some forms are known to cause stomach upsets. Distribution, America and Europe.
The fungus spreads by long black cords called rhizomorphs resembling bootlaces which can be found beneath the bark of infected trees, on roots or in the soil where they can travel large distances to infect other trees. This is one of the most dangerous parasites of trees, causing an intensive white rot and ultimately death; there is no cure and the fungus is responsible for large losses of timber each year.