A large, velvety, annual polypore at the bases of conifers that causes a brown cubical butt rot of roots and heartwood. Young fruiting bodies have yellow to orange margins and a yellow to greenish pore surface that bruises dark brown; old ones turn uniformly rusty brown. It is a classic natural dye fungus.
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Mycology is an evolving science: names, classifications and safety information change as research advances. Entries are compiled from cited sources and reviewed, but may be incomplete or out of date — check the sources, and never rely on this library alone to identify or eat a mushroom.
Habitat
Parasitic on roots and heartwood of living conifers (Douglas-fir, pines, spruces, firs, hemlock, larch) and saprobic on their dead wood, causing a brown cubical butt rot that weakens trees and can lead to windthrow. Fruits at or near the tree base or from roots, so it may appear terrestrial; late summer and fall.
Distribution
Widely distributed in Europe, Asia, North America, Central America and Oceania. In the United States it is common on Douglas-fir in the West, white pine in the East and loblolly pine in the South. Wikipedia treats it as introduced in New Zealand, Australia and South Africa.
Characteristics
Cap: 7-30 cm, single or rosette-forming, velvety when young, dry; dark brown to rusty or olive brown with yellow or olive zones, margin bright yellow or orange when young; often incorporates grass, twigs or needles. Pores: decurrent, orange to bright yellow when young, becoming greenish yellow, olive and then brown; bruise dark brown to nearly black; angular to slot-like, 1-3 per mm; tubes 1-7 mm deep. Stem: usually central, 2.5-5 cm long, 2-2.5 cm thick, brown and velvety; sometimes absent. Flesh: pale brown becoming rusty brown, soft when young, later stringy and leathery. Chemical reactions: KOH black, often with a cherry-red intermediate stage. Spore print: whitish to yellowish. Spores: 6-12 x 3-5 µm, ellipsoid, smooth, inamyloid.
