Ganoderma

by Michael Kuo
Ganoderma lucidum is one of the most beautiful mushrooms in the world, if you ask me. When very young its varnished surface is Chinese red, bright yellow, and white (see the bottom illustrations). Later the white and yellow shades disappear, but the resulting varnished, reddish to reddish brown surface is still quite beautiful and distinctive. While Ganoderma lucidum is annual and does not actually grow more each year like some perennial polypores, its fruiting body is quite tough and can last for months.
Ganoderma tsugae is virtually identical; see the comments below for help separating look-alikes.
Description:
Ecology: Parasitic on living hardwoods (especially oaks) and saprobic on the deadwood of hardwoods; causing a white butt and root rot; growing alone or gregariously, usually near the base of the tree; annual; widely distributed east of the Rocky Mountains, and occasionally recorded in the western states.
Cap: 2-30 cm; at 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.
Pore Surface: Whitish, becoming dingy brownish in age; usually bruising brown; with 4-7 tiny (nearly invisible to the naked eye) circular pores per mm; tubes to 2 cm deep.
Stem: Sometimes absent, but more commonly present; 3-14 cm long; up to 3 cm thick; twisted; equal or irregular; varnished and colored like the cap; often distinctively angled away from one side of the cap.
Flesh: Brownish; fairly soft when young, but soon tough.
Spore Print: Brown.
Chemical Reactions: KOH black or blackish on all surfaces.
Microscopic Features: Spores 9-12 x 5.5-8 µ; more or less elliptical, sometimes with a truncated end; appearing smooth at lower magnifications; under oil immersion appearing double-walled, with a row of "pillars" between the walls. Setae and cystidia absent. Hyphal system dimitic.
REFERENCES: (Curtis, 1781) Karsten, 1881. (Fries, 1821; Saccardo, 1912; Overholts, 1953; Arora, 1986; Gilbertson & Ryvarden, 1986; Lincoff, 1992; Metzler & Metzler, 1992; Horn, Kay & Abel, 1993; Barron, 1999; McNeil, 2006; Kuo, 2007; Binion et al., 2008.) Herb. Kuo 04299504, 09040301.
Ganoderma resinaceum is a synonym, according to some authors.
Ganoderma tsugae is found on conifer wood--especially on hemlock--and has paler flesh; otherwise it is virtually indistinguishable from Ganoderma lucidum. Ganoderma oregonense is a conifer lover of the Pacific Northwest and New Mexico; it has larger spores (10-16 x 7.5-9 µ) and a much larger fruiting body (up to one meter across!). Ganoderma curtisii, known from Massachusetts to Nebraska, grows on hardwoods and has a cap that is described as "entirely ochraceous when young, or partly ochraceous and partly dull red in mature plants" (Overholts, p. 213).