Summary:
Clade Heterophyllidia I. Features include 1) a hard fruitbody, often irregular in shape, often remaining partly buried, 2) a subviscid cap that is brown, yellow, red, or rarely greenish, 3) white flesh that changes slightly to brownish in the cap when bruised, 4) white gills that becoming pale yellow to yellow and occasionally bruise brown, 5) a solid, white stem that may discolor pale brown when handled, 6) mild taste and odor, 7) a preference for Abies and for higher elevations, at least in California, 8) a cream to yellow spore deposit, and 9) microscopic characters including warts and ridges often forming a broken to complete reticulum. The description is derived from Thiers(3) except where noted.

Gills:
"adnate to adnexed, free with age, close to subdistant", subgills absent, gills not forking; "white when young, pale yellow to yellow with age, unchanging in color or occasionally staining brown when bruised"

Stem:
4-9.5cm x 2-3cm at top, "equal to clavate", solid; "white, unchanging in color or changing to pale brown when handled"; dry, bald

Odor:
mild, not distinctive

Taste:
mild, not distinctive

Microscopic spores:
spores 7.6-10.5 x 6.5-9 microns, nearly round to suboval to subelliptic, "ornamentation composed of isolated warts with heavy ridges and fine lines often forming a broken to complete reticulum", warts rarely exceeding 0.5 microns high; hymenial cystidia rare to numerous, 51-107 x 7-14 microns, "projecting from the hymenium, sometimes only slightly, fusoid to cylindric with obtuse apices or a narrow, elongated, often strangulated terminal appendage"; cuticle 45-60 microns thick, "epicutis differentiated as a tangled to interwoven layer of hyphae with free hyphal tips, pileocystidia usually present, sometimes rare or absent"

Spore deposit:
cream to yellow

Notes:
DNA from Ben Woo''s WA, OR, and ID collections matched Russula mustelina. It was reported and described from WA previously by Grund(2) and from BC by Roberts, C.(2). It has also been reported from CA (Thiers(3)).

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