Man on horseback

Description

The man-on-horseback is a medium-sized mushroom with a cap 4–10 cm across, yellow-green or yellow-brown, darker in the centre, slimy and often covered with sand. The gills and stem are yellow, the flesh white, with a smell of fresh flour. It has no ring and no volva.

It grows from October to December in pine forests on sandy soil, usually in groups. Only part of the cap protrudes from the litter, because most of the fruiting body develops underground.

Because of poisonings, including fatal ones, the app treats it as poisonous and does not recommend collecting it. Young specimens are sometimes confused with the death cap, so with any greenish mushroom you must check the base of the stem.

Identification features

Cap

Diameter 4–10 cm (descriptions also give 5–15 cm); conical-convex when young, later flat, often wavy. Colour yellow-green or yellow-brown, darker in the centre. Skin bare or finely scaly, greasy (often covered with grains of sand), slimy in the wet, peelable.

Hymenophore (underside of the cap)

Gills from pale yellowish to sulphur-yellow, moderately crowded (descriptions also give: thin, crowded), thin, notched with a tooth, broadly attached at the base.

Stem

Length 3–9 cm (descriptions also give 4–10 cm), thickness up to 3 cm (descriptions also give 1–2 cm), cylindrical, solid; surface first with longitudinal fibres, then smooth, yellow or yellowish-green, turning brownish at the base. No ring and no volva.

Flesh

Firm, brittle, white, not changing colour when cut. Taste sweetish-nutty, smell of freshly ground flour. Do not taste it.

Spore print and spores

Spore print white. Spores ovoid, smooth, colourless, 6–8 × 3.5–5 µm.

Habitat and distribution

Ecology. Terrestrial mycorrhizal fungus, associated with pine in Europe. Grows in pine forests on sandy soil, with a lot of lichens, almost always in groups, sometimes together with the greenish knight (Tricholoma portentosum, also under the name "gąska niekształtna"). The fruiting body develops almost entirely underground.

Distribution. Widespread in Europe and North America, also reported from Japan, Costa Rica and Africa; abundant in, among others, France and central Portugal. In Poland locally frequent; hard to find, because only part of the cap protrudes from the litter. On the Red List of Plants and Fungi of Poland (2006): category I (insufficiently known / of undetermined threat). Not legally protected in Poland (Dz.U. 2014 item 1408); in some countries (Germany, the Netherlands, Slovakia) it is on threatened lists, and where it is threatened, collecting is prohibited. It is on the Polish list of mushrooms permitted for sale (Ministry of Health, item 11), despite being classed as poisonous in the app.

Fruiting. From October to December.

What can it be confused with?

• Tricholoma sulphureum (sulphur knight) — Flesh yellow, gills widely spaced, unpleasant smell of coal gas or carbide; the man-on-horseback has white flesh, more crowded gills and a mealy smell.
• Tricholoma sejunctum (yellow-green knight) — Cap more olive-grey, occurs mainly in deciduous forests.
• Amanita phalloides (death cap) — Deadly poisonous; young specimens in particular are similar. The death cap has a volva at the base of the stem, a ring, free white gills and a taller stem; the knight has neither ring nor volva.
• Tricholoma frondosae, T. auratum, T. aestuans, T. intermedium — Listed as similar; detailed differences: no data.
• Floccularia luteovirens, F. albolanaripes — Listed as similar; 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

• Linnaeus described the species as early as 1753; the epithet equestre means "of horses, equestrian", hence the English name "man on horseback".
• According to legend, medieval French knights reserved this mushroom for themselves and left the peasants the slippery jack (Suillus bovinus); the account is reputed rather than established.
• In 2001–2003 numerous poisonings by the man-on-horseback were recorded in France, including several fatal ones, and since 2009 a poisoning in Poland has also been documented.
• The species is on the Red List of Poland in category I (of undetermined threat), and on the threatened lists in Germany, the Netherlands and Slovakia.