Trichaptum biforme (Fr. in Klotzch) Ryv. Bracket 1-8cm across, semicircular, fan-shaped, flat; color variable in concentric zones, ochre to dark brown, white to grayish, brownish or black, violet margins; hairy becoming smooth. Tubes 1-l0mm deep. Pores 2-5 per mm, angular, becoming tooth-like; white to brownish with mauve tinge and mauve along the margin. No stem. Flesh 0.5-1.5cm thick; white to yellow. Spores cylindrical, smooth, 5-6.5 x 2-2.5µ. Deposit white. Habitat numerous, single, or overlapping caps on dead stumps of trees of deciduous wood, reducing them to sawdust. Very common. Found widely distributed throughout North America. Season May-December, but often persisting all year. Not edible.