Pileus: 8 - 10 cm broad; convex at first becoming planar to shallowly depressed and finally deeply depressed at maturity; margins inrolled at first then incurved and finally straight and occasionally arched, even when young but cracking to eroded when mature; surface dry to viscid when wet, usually glabrous, but at times velvet-like especially on disc, unpolished, not peeling; colour pallid at first, becoming mottled with light brown colours, then brownish grey to brown, finally black; context 1 - 2 cm at junction of stipe, firm, white at first, becoming red and then dark brown to black when bruised; taste mild; odour indistinct.
Lamellae: Ascending at first, then horizontal and finally decurrent, distantly spaced, thick and waxy, edges even but becoming black when bruised, broad, forking towards stipe; colour white becoming grey black with age; 1 lamellulae.
Stipe: 4 - 8 cm long X 2.5 - 3.5 cm wide, equal to tapering downwards, dry, glabrous, unpolished, white to pallid at first and at the apex, darkening to grey black when bruised, yellowish to light brown at the base; context solid, spongy, white at first, then red and finally black when bruised.
Comments: This species is one of the few Russula species in these forests with regular lamellulae. It is easily recognized by its wide and distant gills and the colour changes that proceeds from pallid to red to black when injured.
Arora, D. 1986. Mushrooms Demystified. Ten Speed Press. Berkeley, Ca. pp 958.
Thiers, H.D. 1997. The Agaricales (gilled fungi) of California. 10. Russulaceae I. Russula. Mad River Press. Eureka Ca. pp 158.