Fragile brittlegill

A small, colourful brittlegill that seems unwilling to settle on any single shade.

Cap

The cap (2-6 cm across) moves freely through lilac, purple, violet, pinkish-red and olive-green, often blending two or three tones at once, with a paler whitish centre and a more saturated margin.

It starts convex and broadens to nearly flat, sometimes dipping slightly at the centre. The surface is smooth, faintly tacky in wet weather, and the skin peels cleanly halfway to the centre - a useful russula check.

Gills

White to very pale cream, crowded, and carry a distinctly serrate (finely saw-toothed) edge: this is the key field mark, best confirmed with a hand lens or strong side-light. Spore print white.

Stem

White, 2-5 cm tall × 0.5-1.2 cm wide, firm when young then hollow, and - like all russulas - genuinely brittle, crumbling cross-wise when broken. No ring, no volva.

Smell & taste

Smell faint. Taste: burning-acrid from first contact, among the most fiercely peppery of any common European russula.

Not life-threatening: R. fragilis causes gastrointestinal poisoning, not organ failure.

Its danger lies in two directions:

1. 1Eating it raw or under-cooked causes unpleasant illness.
2. 2Its variable and sometimes attractive colouring may lead novice foragers to compare it with edible russulas and misjudge it as safe.

Always taste-test russulas individually.

The broader ID risk is that small russulas growing in Amanita habitat may be confused with Amanita buttons; always dig up the full base to check for a volva.

Acrid sesquiterpenoid-related irritant compounds concentrated in the cap cuticle and gills.

The same broad class of irritants responsible for acridity in R. emetica, R. sardonia and related species.

Ingestion of raw or insufficiently cooked material causes gastrointestinal irritation - nausea, vomiting and diarrhoea - beginning within 30 minutes to 2 hours of consumption.

Symptoms are self-limiting and rarely require medical intervention beyond hydration, but can be severe.

No liver, kidney or neurological toxicity is documented.

Russula fragilis is toxic and produces gastrointestinal poisoning from acrid irritant compounds (sesquiterpenoid-related pungency).

It is not lethal, but its intense acridity means even careful cooks risk retaining enough irritant to cause illness.

The genus Russula does not carry amatoxins, orellanin or gyromitrin.

Conservative practice: treat R. fragilis as inedible and leave it.

Like all russulas, R. fragilis is mycorrhizal - it lives intertwined with tree roots, trading mineral uptake for sugars in a partnership that can last as long as the tree itself.

Its preferred partners are beech, oak and hazel in deciduous and mixed woodland, occasionally birch or spruce.

It favours moist, humus-rich, slightly acidic soils in sheltered spots among leaf litter, and turns up from lowland river-terrace woods to montane beech forest across temperate Europe.

Widespread and locally common, but its small size and chameleonic colouring mean it is easy to walk past.

Mid-summer to autumn: mid-July through October in most of central and western Europe.

Peaks in August and September after late-summer rain.

Appears singly or in small scattered groups among leaf litter and mosses on the forest floor - the classic russula fruiting pattern, driven by underground mycelium rather than any surface substrate.

Never clustered on wood.

Flushes after summer and early-autumn rain when soil temperatures are between 9 and 18 degrees C; typical mycorrhizal russula fruiting pattern. Lag from triggering rain to visible fruit-body 5-12 days.

• Russula emetica (Sickener) is very similar, with a red to pink cap, white gills and acrid taste, and is equally inedible; R. emetica typically has a more uniformly red cap and prefers conifers and sphagnum bogs, whereas R. fragilis favours broadleaf trees and shows more lilac-violet tones.
• Russula nobilis (Beechwood sickener) is also red-capped, acrid and associated with beech; all three are equally inedible.
• Some Cortinarius species in shades of violet-lilac can superficially match the colouring of R. fragilis, but Cortinarius has fibrous flesh, a cobweb-like cortina when young and a rusty-brown spore print, while R. fragilis has no cortina, white spores and brittle flesh.

The critical general caution for all small russulas: always excavate the full stem base to confirm there is no volva (bag-like sack), which would indicate a deadly Amanita, particularly Amanita phalloides.