Goatcheese Webcap Identification Guide

The first impression

You meet Goatcheese Webcap in old, mossy conifer forest - spruce above all, on acid ground, with bilberry and feather moss carpeting the floor and very little direct light reaching it. Autumn, after rain. The fruitbodies push up through moss in scattered groups, and what stops you is the colour: a soft, chalky violet-blue, more pastel than purple, with a silky sheen that catches low light like brushed silk.

The second thing that reaches you is the smell, and it usually arrives before you have finished kneeling. It is strong, penetrating and unmistakably unpleasant to most noses - stale goat cheese is the standard comparison, with rotten potatoes, sweaty leather or a hot animal shed as alternatives. It lingers on the fingers and it fills a collecting basket. In a genus where most species are hard to name in the field, this combination of pale lilac colours with a powerful odour narrows things down immediately.

Working through the cap

Measure and feel before you record colour, because the colour changes fast. The cap is 4-10 cm across, hemispherical then convex, finally almost flat with a broad low umbo, and the margin is inrolled and often ragged with veil fibres in youth.

The surface is dry, never slimy or greasy. Under a lens it is finely silky-fibrillose, with radiating pale fibres over a violet ground, and older caps develop a slightly matted or minutely felty look. Colour begins as a clear pale violet-blue and then ages from the centre outward through greyish lilac to buff, clay and dull ochre, so a mature troop can show a full gradient from lilac buttons to almost brown veterans. Judge the species on the youngest specimens present.

Gills, veil and the spore-bearing surface

Underneath, the young gills are the same soft bluish lilac as the cap, moderately spaced, adnate to notched, with slightly uneven edges. They do not keep that colour. As spores ripen they run through clay-buff and cinnamon to a full rusty brown, and by the time the cap has faded to ochre the gills are already rust-coloured.

Check for the cortina on a button. Fine pale silky threads run from the cap margin to the stem, and when they collapse they leave a faint fibrillose zone that becomes stained rusty by falling spores. That web is the genus character. Never confuse it with a true membranous ring - it is more like the remains of a spider web dusted with rust.

The stipe and its base

The stem is 6-12 cm long and 1-2 cm thick, distinctly club-shaped, thickening downward into a swollen but rounded base. Importantly the base is not sharply rimmed or marginate - there is no abrupt shelf around it, just a gradual bulb. It is dry and silky, the same pale lilac as the cap when fresh, and it is usually wrapped with whitish veil fibrils that can form a few vague bands before fading to ochre.

Extract it fully. Spruce litter and moss hide a surprising amount of stem, and the shape of the base is one of the features you will need.

Flesh and internal colour - the decisive cut

Split a fruitbody lengthwise with one clean stroke. This is the single most useful test for this species and it takes two seconds.

The flesh of Goatcheese Webcap is whitish to pale bluish-violet, strongest in the stem apex and just under the cap surface, becoming paler and more washed-out with age. It does not develop a rich brown, saffron or rusty marbling in the stem interior. There is no latex, and cut surfaces do not blue, redden or blacken in any obvious way. Hold the split fruitbody to your nose at this point - the odour is at its most concentrated from freshly exposed flesh.

Spore print technique

Remove a mature cap, set it gills-down on white paper or a slide, cover it with a bowl and leave it four to twelve hours somewhere cool and still. The deposit is rusty brown. Gather it into a thick pad with a blade before assessing the colour; thin deposits mislead.

Under magnification the spores are elliptical to almond-shaped and covered in low warts, roughly 8-10 x 5-6 micrometres. Rusty print, warted spores and a cortina together confirm Cortinarius, at which point the field characters carry the species.

Habitat and season

Strictly mycorrhizal with conifers, especially Norway spruce and occasionally pine, on acid, often nutrient-poor and mossy soils. It likes mature stands with a deep moss layer, and it fruits from late summer to late autumn. It grows from the ground, never from wood. In broadleaved woodland with no conifer present, look elsewhere for your lilac mushroom.

Separating the look-alikes on structure alone

Several pale lilac webcaps grow in the same forests, and the cut stem plus the odour settles almost all of them.

• Cortinarius traganus is the critical comparison. It shares the dry silky lilac cap, the club-shaped base and conifer habitat, but when you split it the stem flesh is a distinct saffron to rusty brown, often marbled, and the smell is quite different - fruity and acetylene-like, often compared with overripe pears. Pale flesh plus goat cheese odour equals camphoratus; brown-marbled flesh plus a fruity smell equals traganus.
• Cortinarius alboviolaceus is paler still, silvery-white with only a wash of lilac, has whitish flesh, a mild or faint smell, and grows with broadleaves, especially birch and beech.
• Cortinarius malachius and its relatives are thinner-fleshed with a more scurfy cap surface and lack the strong odour.
• Cortinarius anomalus is smaller, greyish-lilac only at the cap edge and stem apex, and characteristically shows distinct ochre-yellow veil girdles on the stem.
• Lepista nuda can look superficially similar in colour but has no cortina, keeps its lilac gills far longer, has a fibrous non-bulbous stem, and drops a pale pinkish-buff print rather than a rusty one.
• Laccaria amethystina is smaller, deeply and uniformly violet, with thick widely spaced gills that stay violet and a white spore print, and it lacks any cobwebby veil.

Field checklist

Pale violet-blue dry silky cap fading ochre; lilac gills turning rusty; cobwebby veil with rusty staining; club-shaped, non-marginate swollen base; pale bluish-white flesh with no brown marbling; strong penetrating goat-cheese odour; mossy spruce forest on acid soil in autumn; rusty warted spore print. Confirm the cut flesh and the smell together and the identification is secure.