violet-toothed polypore

Growing to 1–7.5 centimetres (1⁄2–3 in) in width, it is initially violet before fading into zones of white to brown, retaining violet at the margin for a time.

Similar species. It is sometimes confused with Trichaptum abietinum, which grows almost exclusively on conifers, as do T. byssogenum and T. fuscoviolaceum. Skeletocutis lilacina is also similar.

T.biforme is a saprobe that decomposes hardwood stumps and logs. Widely distributed, it occurs on at least 65 tree hosts. It rarely grows on conifers, but has been recorded from pine (Pinus) deadwood. T.biforme was once recorded in association with the little-known pleasing fungus beetle Haematochiton elateroides, but it is suspected that the beetles were not feeding on this tough and leathery fungus, but simply hibernating in the dead log on which it grew.