Menthol brittlegill or Blackening brittlegill

Cap 6-15 cm across; in young mushrooms hemispherical to flat with an inrolled margin, later becoming funnel-shaped. Color pure white when young, turning gray, ash-gray, then blackish with age. Surface smooth, slightly sticky in wet weather.

Cap 8-20 cm across; in young mushrooms hemispherical to flat with an inrolled margin, later becoming funnel-shaped. Color white when young, turning dirty gray, ash-gray, then blackish to anthracite black with age. The cap darkens when pressed — unevenly in young specimens. Surface smooth, slightly sticky in wet weather.

Gilled hymenophore — the gills are attached to the stem, moderately crowded (unlike R. nigricans, where they are distant). In young mushrooms — whitish, when damaged they blacken with no red stage. Spore print white.

Gilled hymenophore — the gills are attached to the stem, distant and thick, typical of the genus Russula. In young mushrooms — whitish, when damaged they redden to brownish-black, darkening with age to gray, then black. Spore print white.

Stem 3-7 cm tall, 1.5-3 cm thick, thick, cylindrical. Color white when young, gray to blackish with age. Surface smooth. No ring.

Stem 4-8 cm tall, 2-4 cm thick, thick, fleshy, cylindrical, relatively short. Color white when young, turning gray, then blackish with age. Surface smooth. No ring.

Flesh firm, fleshy, white when young. When cut, it blackens IMMEDIATELY to gray-black, with no red stage — the key difference from R. nigricans. Faint, pleasant mushroomy smell.

Flesh firm, fleshy, white when young. When cut, a two-phase reaction slowly unfolds (over 5-10 min): first it reddens to wine-red or bright carmine, then after a few more minutes it blackens to anthracite black. This is the classic diagnostic feature of the species. Faint mushroomy smell.

Faint, pleasant, mushroomy, with no distinctive notes.

Faint, pleasant, mushroomy, with no distinctive notes.