Spotted tricholoma

Description

The spotted tricholoma is a large, stout mushroom with a cap 4–10 cm across, whitish to silvery grey, covered with concentrically arranged dark grey or brown-black scales. The gills are white, sometimes with a greenish tint, and young ones exude clear drops. The stem is thick, white, with no ring, and the flesh is white, with a pleasant, mealy smell and taste.

It grows from August to October in coniferous and deciduous forests, under spruces, firs, beeches and oaks, on calcareous soils, singly or in small groups. In Poland it is fairly rare.

It is easily confused with grey knights, e.g. the grey knight and the charbonnier. A good, pleasant smell and taste are no proof of safety. Do not collect grey knights with a scaly cap unless you are certain of the species.

Identification features

Cap

Diameter 4–10 cm (descriptions also give 5–15 cm); hemispherical or bell-shaped-convex when young, then flattened, with a broad, shallow umbo; margin at first inrolled. Surface whitish to silvery grey, dry, with concentrically arranged grey-brown or black-grey scales, paler towards the margin.

Hymenophore (underside of the cap)

Gills at first white, often with a greenish tint, then pale yellowish, never grey; thick, moderately crowded, notched with a tooth (free according to some descriptions). Young ones exude clear drops on the edge.

Stem

Height 6–12 cm (descriptions also give 3–12 cm), thickness 2–4 cm (descriptions also give 1.5–3 cm), cylindrical or bulging, often thickened at the base. Surface white, ochre in the lower half; at the top often exuding clear drops. The base turns dirty ochre or yellow when damaged. No ring and no volva.

Flesh

White, not changing colour when cut. Taste and smell pleasant, mealy, not very pronounced. Do not taste it: the pleasant taste increases the risk of poisoning.

Spore print and spores

Spore print white. Spores ovoid to oblong, smooth, colourless, non-amyloid: 8–10 × 6–7 µm (descriptions also give 7.5–9.5 × 5–7 µm).

Habitat and distribution

Ecology. Mycorrhizal fungus; grows under spruce, fir, beech or oak, only on calcareous soils (according to some descriptions it prefers higher elevations), singly or in a few specimens, rarely in groups or rings.

Distribution. Europe (more frequent in the south, abundant in the Jura in France), North America, parts of Asia. In Poland fairly rare. Not legally protected in Poland.

Fruiting. From August to October (descriptions also give: summer and autumn).

What can it be confused with?

• Tricholoma scalpturatum (yellowing knight) — Almost deceptively similar; turns yellow with age and when damaged (a process taking several hours).
• Tricholoma terreum (grey knight) — Smaller, darker and less massive, thinner flesh, no mealy smell and no cap scales, smaller spores (5–7.5 × 4–5 µm).
• Tricholoma portentosum (charbonnier) — Similar in size, but the cap is uniformly grey, never scaly.
• Tricholoma atrosquamosum (dark-scaled knight) — Similarly scaly cap, but smaller and darker, with a peppery, fruity or pelargonium smell.
• Tricholoma orirubens (reddening knight) — Cap and flesh slowly turn red when damaged; finer dark scales, pinkish gills, brittle flesh, usually smaller.
• Tricholoma cingulatum (willow knight) — Grows only under willows.
• Tricholoma myomyces, T. argyraceum — T. myomyces is smaller, with a thin fibrous veil when young and smaller spores; T. argyraceum has finer scales, and its gills and damaged areas turn yellow with age.

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 epithet pardinum comes from Latin pardus "leopard", from the spotted pattern of scales on the cap; English names include "tiger tricholoma" and "leopard knight".
• The name "dirty trich" was coined by Gary Lincoff at the request of a publisher who wanted an easier name than the Latin one.
• The name Tricholoma tigrinum was wrongly applied to this species in European guides; the Czechs Herink and Kotlaba proposed the name T. pardalotum in 1967.
• The species can be abundant in warm, rainy years, and in other years disappears or is rare.