Pileus: 5.5 - 11 cm broad; convex when young, becoming planar and finally depressed at maturity; margins inrolled at first, becoming straight and even, finally uplifted, at times eroded, striate; surface dry to viscid, smooth, unpolished when weather is dry, but can be polished, peeling readily till disc; colour variable, ranges from olive yellow to dark green to reddish brown; olive, violet brown, dark ruby, dark to greyish green on disc, paler or with yellow tones towards margins; context 0.3 - 1.0 cm at junction of stipe, fleshy to spongy, colour white to brownish grey, slowly bruising red then finally black; taste mild; odour indistinct to variously described as wine-like, fermenting-like.
Stipe: 4.0 - 11.0 cm long X 2.0 - 3.5 cm wide at apex, 1.5 - 3.0 cm wide at base, tapering downward or equal; surface dry, unpolished, fibrous, often with grooves or striations; colour white bruising red at first then black; context solid, spongy, with a thick rind, white to pallid, then yellow, bruising grey black at times without turning red first. Turning red with application of PDAB.
these forests, this species can be confused with R. aeruginea,
or R. xerampelina. R. occidentalis is separated from
these 2 species because R. occidentalis turns red then
black when bruised while the other 2 species do not. R. aeruginea
does not show any colour changes, while R. xerampelina may
show some yellow to yellow brown when bruised. Tissue of R. occidentalis
will turn bright red with PDAB,
in the other species it will not .
Arora, D. 1986. Mushrooms Demystified. Ten Speed Press. Berkeley, Ca. pp 958.