Ganoderma sessile is a laccate (varnished) annual polypore of eastern North America, usually lacking a stem. For many years it was included in G. lucidum in North America; DNA studies show G. lucidum is not native there and that G. sessile is a distinct species. It is saprobic and sometimes parasitic on hardwoods, causing a white rot.
Not a food mushroom: tough and corky. The sources reviewed give no species-specific edibility or toxicity data. Laccate Ganoderma are traditionally prepared as teas or extracts rather than eaten, and products sold as reishi may contain this species.
Never eat a wild mushroom based on a web page — confirm with an expert.
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 Entries are compiled from cited sources and reviewed, but may be incomplete or out of date — check the sources, and never rely on this library alone to identify or eat a mushroom.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
On trunks, root flares, stumps and logs of living or dead hardwoods; annual, fruiting spring through fall.
Distribution
Eastern North America; common in practically every US state east of the Rocky Mountains. Originally described from New York.
Characteristics
Cap: 3-30 cm across; semicircular to irregularly kidney-shaped; surface lacquered, brownish red to reddish brown, sometimes with paler tan, orange or yellowish zones, darkening and wrinkling with age. Pores: Whitish to pale brownish, becoming medium to dark brown, bruising darker brown; 2-4 per mm; tubes to 7 mm. Stem: Usually absent; when present lateral and stubby, to 5 x 2 cm, varnished. Flesh: Tough, pale tan to pale brown, with concentric growth zones but no melanoid bands. Chemical reactions: KOH black. Spore print: Reddish brown. Spores: 8.5-14 x 5.5-8 um, ellipsoid, truncate, double-walled. Key features: Varnished red-brown cap, usually stemless; large spores; growth zones without melanoid bands.
