Sickener Identification Guide

The first impression

The Sickener is a fungus of wet ground. You find it in soggy conifer woodland, along the edges of sphagnum bogs, in peaty hollows under pine and spruce, and in the mossy seepages of upland plantations - places where your boots sink slightly and the moss is saturated. Against that green and rust-brown background the cap is startling: a pure scarlet or cherry-red disc, glossy with wet, perched on a chalk-white stalk. The fruit bodies are usually single or in loose scattered groups rather than dense troops, and they look fragile, which they are. Pick one carelessly and the stalk shatters. That brittleness, together with the pure white gills and stalk under a vividly red cap, defines the search image.

Reading the cap

The cap is 3-10 cm across, convex at first, then flattening and often becoming shallowly depressed at the centre. The colour is a bright, saturated scarlet to blood-red or cherry-red, though rain, sun and age all wash it out - it is very common to find caps that have faded to rose-pink, salmon, or even to irregular white patches where the pigment has leached away entirely, especially at the centre and along the margin. The surface is smooth, sticky when moist and shining when dry. Two structural characters matter more than colour. First, the cuticle peels: grip the edge of the skin and it strips away almost to the centre of the cap in a single sheet, revealing pinkish-tinted flesh underneath. Second, the margin becomes strongly grooved with age - short, sharp, tuberculate striations that mark out the positions of the gills below, extending inward a centimetre or more on a mature cap.

The gills

The gills are pure white and stay white, at most acquiring the faintest cream tint in old age. They are rather broad, relatively well spaced compared with many brittlegills, adnexed to almost free at the stalk, and equal in length with few forks. Their edges are entire and concolorous. Run a fingertip across them: they crumble in brittle flakes rather than folding, the essential test that puts a mushroom into the brittlegill genus. Held up to the light, the gill faces have a slightly greasy, translucent look when the fruit body is fresh and wet.

Stalk, base and flesh

The stipe is 4-9 cm long and 1-2 cm thick, white throughout, dry, cylindrical or slightly clavate and widening downward, with a finely wrinkled or minutely ribbed surface. There is no ring and no sac or volva at the base, and the base is not rooting; the stalk simply ends bluntly in the moss with a few white mycelial threads. Snap it in half rather than cutting: it breaks cleanly and audibly, like a stick of chalk, and the interior is spongy and chambered rather than solidly fibrous. In cross section the flesh is white and unchanging, with a distinct pink or reddish zone immediately beneath the cap cuticle - visible if you slice the cap vertically through the skin. Older stalks may yellow or grey slightly as they decay, but there is no rapid bruising reaction of any kind. The odour is faint, sometimes described as slightly fruity or coconut-like when the flesh is crushed.

Taking a spore print

Spore print colour is critical in this genus, because red-capped brittlegills are separated in large part by the exact shade of their deposit. Cut a mature cap free, set it gills-down on pure white paper, cover it and leave it several hours. Scrape the deposit into a thick heap with a blade and read it in daylight against the white background. The Sickener drops a white to very pale cream print, at the palest end of the scale. Microscopically the spores are broadly ellipsoid and ornamented with prominent warts joined by fine lines into a partial network, and the ornamentation stains blue-black in Melzer's reagent.

Substrate, partners and season

This is a root-partner species of conifers, and it is closely bound to wet, acidic, peaty ground. Its classic setting is sphagnum under spruce and pine, but it also appears in damp needle litter in conifer plantations and in boggy mixed woodland where conifers are present. It is not a wood-rotter and will not be found on stumps or logs, though it frequently grows out of deep moss on rotting buried timber. The season runs from midsummer to late autumn across the boreal and temperate north, with the best flushes after heavy sustained rain. Habitat is a real identification character here: a bright red brittlegill from dry beech leaf litter is a different species.

Separating the look-alikes

Russula mairei, the beech brittlegill, is the closest match in colour. It grows with beech on dry, often chalky ground, is smaller and noticeably firmer in the flesh, its cuticle peels only a short way in from the margin rather than to the centre, and its gills are more crowded and often take on a faint blue-green tinge in age.

Russula betularum is a birch and bog species, similar in shape but much paler - a washed pink or rose over a whitish ground - and slighter throughout.

Russula silvicola and its allies grow with both hardwoods and conifers, have shorter stalks, a cuticle that peels only partway, and drop a cream rather than white print.

Russula sanguinaria grows with pine on sandy soil, and is separated at a glance by its stalk, which is flushed rose or red rather than pure white, and by a cuticle that will not peel.

Russula rosea has a hard, matte, almost powdery cap surface, very firm flesh and a cuticle that resists peeling entirely.

Russula paludosa shares the bog habitat but is larger and more robust, its cap orange-red and typically paler toward the centre, and it drops a deeper cream to ochre print.

Amanita muscaria is red-capped and grows in the same woods, but has white warty patches on the cap, a ring on the stalk, a bulbous base ringed with tissue, and tough fibrous flesh that does not shatter.

Waxcaps and Mycena species with red caps are elastic and pliant, bending rather than snapping.

Field checklist

Wet acid conifer ground or sphagnum; scarlet cap fading and peeling almost fully; grooved margin in age; broad white gills; brittle white stalk with no ring; pink zone under the cuticle; white to palest cream spore print. That set defines Russula emetica.