Dyers Mazegill (Phaeolus schweinitzii) is to be found only with conifers, so it is quite common in the New Forest due to the many enclosures of these trees.
The Douglas firs that grow alongside the Ornamental Drive near Rhinefield House, Brockenhurst is always a good place to see it.
It is a bracket or shelf fungus, but can sometimes grow vertically direct from a tree root, when it will form a circular shape of tiered fruiting bodies fused together. It is parasitic on conifers and will cause brown cubical rot.
The time of active growth, however, is in the autumn when the fruiting bodies have a bright yellow growing edge to the bracket or, if very immature and erupting from a root, they may be circular and soft, starting as a large, bright yellow lump. The large semi-circular, or fan shaped, brackets may be up to 3 cm across, the yellowish brown velvety or hairy top is concentrically grooved with depressed dark brown centre. The actively growing margin will be quite bright shades of yellow and brown and is comparatively soft. The underside has elongated, irregular, maze like pores that are yellow, but bruise brown and then whole underside becoming brown with age.
The name Dyers Mazegill is an old one, from when this fungus was used in dying yarn in shades of yellow, orange or brown, which depended on the age of the fruit body. Natural dyes were used until 1856 when coal-tar dyes were invented, followed by synthetic dyes in the early 2 th century. Dyers Mazegill could also be used as a mordant to bind the fibres in the dying process. The underside of the fungus in those times could have been mistakenly referred to as ‘gills’ instead of pores, because of their elongated appearance.