Horse mushroom or Spotted toughshank

Cap 6-20 cm across; in young mushrooms firmly hemispherical to egg-shaped, the margin often rolled under. Later it becomes convex to flat. Color pure white to cream, with subtle yellowish tints in old mushrooms; spots yellow to ocher when touched. Surface smooth, slightly sticky in wet weather, dry and matte in dry weather. Sometimes with fine fibrous scales in the center.

Cap 5-15 cm across, firm, fleshy, when young convex with an inrolled margin, becoming with age flat-expanded with a slightly wavy margin. Cap skin smooth, dry, matte. Color when young — pure white to cream, with age it becomes covered in characteristic rusty-red spots and marbling, especially in the center and on damaged areas. Old fruiting bodies are cream-ochre overall with reddish streaks.

Gilled hymenophore — gills free, crowded. When young — grayish-white, with a pinkish tinge, becoming with age dark brown, chocolate-blackish. Spore print dark brown.

Gilled hymenophore — the gills are adnate or free, very crowded, thin, whitish to cream, gradually turning reddish when damaged — a diagnostic trait. Spore print pale pink to cream (a typical Rhodocollybia trait).

Stem 6-12 cm tall, 1.5-3 cm thick, thick, fleshy, cylindrical, slightly thickened at the base. Color white to cream. On the upper part — a large membranous double ring with a characteristic "toothed" lower edge (like a cogwheel) — a diagnostic feature of the species.

Stem 5-12 cm tall, 1-2 cm thick, cylindrical, firm, fleshy, thickening toward the base with a "root-like" extension into the substrate. Color white at first, with age covered in the same rusty spots as the cap. Surface smooth or with lengthwise fibers.

Flesh firm, meaty, white; when cut it slowly yellows in the flesh of the cap and upper stem. Does not redden (unlike A. silvaticus). The smell is a distinct anise-almond — a characteristic feature of the species.

Flesh firm, white, marbled. When cut, it slowly (over 10-30 min) turns cream-reddish — oxidation, a characteristic reaction. Smell faintly mushroomy, taste distinctly bitter and astringent — and this is the main reason it's inedible.

Distinctly anise-almond, fruity — the most characteristic diagnostic sign. It comes out when you rub the flesh between your fingers. This smell is one of the most pleasant mushroom experiences in field foraging.

Faint, neutral, mushroomy, nothing distinctive.