The reishi mushroom is Saprobic; growing alone or in groups on decaying hardwood logs and stumps (rarely on conifers); annual; widely distributed but more common in eastern North America. The cap is 2-20 cm, first irregularly knobby or elongated, but by maturity more or less fan-shaped; with a shiny, varnished surface often roughly arranged into lumpy "zones"; red to reddish brown when mature; when young often with zones of bright yellow and white toward the margin. The Pore Surface is white, becoming dingy and brownish in age; usually bruising brown with 4-7 tiny (nearly invisible to the naked eye) circular pores per mm; tubes get to 2 cm deep. The stem sometimes absent, but more commonly present; is 3-14 cm long, and up to 3 cm thick, it is twisted and equal or irregular, it is varnished and colored like the cap but often distinctively angled away from one side of the cap. The flesh is a brownish yet fairly soft when young, but soon toughens.
Ganoderma lucidum (MushroomExpert.Com), http://www.mushroomexpert.com/ganoderma_lucidum.html (accessed January 24, 2017).