Stinky Knight

Description

The stinky knight is a medium-sized mushroom with a cap 3–8 cm across, sulphur-yellow or olive-yellow, darker in the centre. It has rather thick, widely spaced, bright yellow gills and yellow flesh. The stem is sulphur-yellow with rusty fibrils, with no ring. It is easiest to recognise by its repulsive smell, like coal gas or carbide.

It grows from August to November in deciduous and mixed forests, often under pines and beeches, on the ground among grasses and twigs. In Poland it is fairly common.

It is sometimes confused with the man-on-horseback, but it has yellow flesh, more widely spaced gills and a disgusting smell. Raw, it contains substances that dissolve blood, and once cooked it is inedible because of its unpleasant taste.

Identification features

Cap

Diameter 3–8 cm; conical-convex when young, later flat, with an indistinct small umbo. Margin sharp, surface bare or finely scaly, slimy in the wet. Colour sulphur-yellow, olive-yellow, in places reddish-brown; centre darker, very delicately covered with purple flakes.

Hymenophore (underside of the cap)

Gills bright yellow, rather thick, widely spaced, notched with a tooth (attached or notched according to some descriptions). The widely spaced gills are an important feature distinguishing the species from the man-on-horseback.

Stem

Height 4–10 cm, thickness up to 2 cm, cylindrical or club-shaped; at first solid, later hollow, sulphur-yellow, covered with rusty fibrils, whitish and hairy at the base. No ring.

Flesh

Yellow. Smell unpleasant, like carbide or coal gas (according to some descriptions skatole; also described as sickly, rotten); taste bitter. Do not taste it.

Spore print and spores

Spore print white. Spores fairly large, ovoid, smooth, colourless, 9–12 × 5–7 µm.

Habitat and distribution

Ecology. Terrestrial mycorrhizal fungus; grows on the ground among grasses and fallen twigs in deciduous (especially beech) and mixed forests, often under pines, with no particular soil pH requirements; in North America also under conifers.

Distribution. Europe and North America, also confirmed in China. In Central Europe widespread but scattered; in Poland fairly common. In Turkey it is considered critically endangered. Not legally protected in Poland.

Fruiting. From August to November (descriptions also give: from spring to autumn).

What can it be confused with?

• Tricholoma equestre (man-on-horseback) — White flesh, more crowded gills, mealy smell, sticky cap; the stinky knight has yellow flesh, widely spaced gills and an unpleasant smell of gas. The man-on-horseback is itself classed as poisonous in the app.
• Tricholoma inamoenum — Very similar, also with an unpleasant smell; detailed differences: no data.

Never rely on a single feature. If you are not sure — do not pick it; show the mushroom to a qualified mushroom expert.

Interesting facts

• The smell of the stinky knight, according to some descriptions caused by skatole, has been compared to coal gas, jasmine, hyacinth, lilac and rotting hemp, among others; the English names "gas agaric" and "stinker" come from this smell.
• The species was described as early as 1784 by Jean Baptiste Bulliard, and Paul Kummer moved it to the genus Tricholoma in 1871.
• In Turkey the species is considered critically endangered.