Russula firmula

Species typical of conifers, especially Picea, with a hemispherical to applanate pileus with a depressed center, 3 to 7 cm in diameter, grey to brownish with abundant violaceous tints; dark yellow spore print; whitish, crumbly stipe; apple-like odor and moderately acrid taste.

Cuticle formed by cylindrical hyphae, densely interwoven, 3 to 5 µm wide, branched, with terminal hyphae acting as dermatocystidia or pileocystidia, cylindrical to clavate, 4 to 9 µm wide, with abundant granular content inside, septate with simple septa.

Cheilocystidia predominantly fusiform, sometimes with a small apical appendage, 50 to 90 µm long and 7 to 10 µm wide.

Pleurocystidia of very similar morphology, 65 to 95 µm long and 9 to 12 µm wide; both cheilocystidia and pleurocystidia contain abundant blackish-grey granular content inside.

Spores spherical to subglobose, with warts up to 1 µm high, 6.5 to 9 µm long, 6 to 7.5 µm wide, ornamented with numerous coarse, scattered, isolated warts that do not coalesce to form ridges.