Wood Blewit Identification Guide

First Impression and Setting

Wood Blewit is a mushroom of the tail end of the season. You find it in November and December, sometimes into a mild January, when almost everything else in the woods has collapsed. The setting is deep leaf litter: beech and oak mast under a hedgerow, drifts of needles at the edge of a spruce plantation, a bank of rotting bramble clippings, or the cooling shoulder of a garden compost heap. The fruit bodies come up in troops, arcs and full rings, and they push litter aside as they rise, so each cap wears a collar of stuck leaves. The first impression is of a solid, fleshy, faintly violet mushroom with a rolled edge, sitting low and stout in the leaves.

Reading the Cap

The cap is 5 to 15 cm across, convex at first with a strongly inrolled margin, expanding to nearly flat and often developing a broad low hump and a wavy, irregular outline. The surface is smooth, bald and slightly greasy when damp, never scaly or fibrous. Colour is where beginners go wrong. A young, fresh specimen is a clear lilac to bluish-violet all over; but this species is hygrophanous, meaning it loses water and colour as it ages and dries, so the cap fades from the centre outward through pinkish-lilac to tan, buff and finally a dull brownish grey with only a violet rim left. Never reject a candidate because its cap is brown — check the gills and stipe instead, which hold their colour far longer.

Reading the Gills

Turn the cap over. The gills are crowded, fairly narrow, and clearly notched where they meet the stipe: they run in toward the centre, then step abruptly upward in a small concave scoop, an attachment described as sinuate or emarginate. They are not decurrent, so they do not run down the stipe. Colour is bright lilac in youth, fading to pale violet, then buff-pink and eventually a dingy pinkish-tan or brownish shade in old specimens. Now perform the separability test that defines the genus: slide a thumbnail sideways under the gills near the margin. In Lepista the whole gill layer peels away from the cap flesh cleanly, like a sheet lifting off. Few other litter agarics do this.

Stipe, Base and Flesh

The stipe is 4 to 10 cm long and 1 to 2.5 cm thick, solid, stout, and often thicker toward the base. Its surface is longitudinally fibrillose and coloured lilac to violaceous, usually more strongly and more persistently than the cap; on faded specimens the stipe is your best remaining colour evidence. There is no ring and no veil remnant of any kind — an important negative. The base is swollen to slightly bulbous and clothed in a mat of lilac to whitish mycelium that binds leaves and soil into a firm plug; lift the mushroom rather than snapping it so you can see this. Slice the fruit body lengthwise: the flesh is thick, firm, pale lilac to whitish, and shows no dramatic colour change, at most a slow brownish discolouration in the stipe base after some minutes. The odour is sweetly perfumed and faintly floral, quite unlike the earthy smell of the litter around it.

Taking and Reading the Spore Print

The spore print is the character that closes the identification, and it is subtle enough that technique matters. Choose a fully expanded cap whose gills have started to lose their brightest violet. Cut the stipe off flush with the gills, set the cap gills-down on a sheet that is half white and half black, cover it with a bowl or upturned glass to stop draughts, and leave it four to six hours or overnight in a cool room. Lepista nuda drops a pale pinkish-buff print — a dirty, washed-out pink that on white paper can look almost cream until you tilt the sheet to the light or scrape the deposit into a small heap with a blade. Piling the powder concentrates the colour and removes any doubt. Under a microscope the spores are small ellipsoids with a finely roughened, minutely warted surface, which is what dulls the pink.

Substrate and Season

This is a litter saprotroph, not a wood or root associate. It decomposes fallen leaves, needles, twigs and garden debris, and it thrives in nutrient-rich, disturbed situations: hedge bottoms, shelterbelts, park shrubberies, conifer plantations, compost. It fruits late, typically from October through December in temperate regions, and it tolerates the first frosts better than almost any other fleshy agaric, often reviving after a freeze. Ring and arc formation is common where the mycelium has spread outward through a uniform leaf bed for years.

Separating the Look-alikes on Morphology Alone

The webcaps, genus Cortinarius, contain many violet species and are the serious confusion. Two structural checks settle it. First, look for the cortina: young webcaps have a cobwebby veil of fine fibres stretched from cap margin to stipe, and even in maturity its remains leave a faint fibrillose ring zone on the stipe, often stained rusty. Second, look at old gills and any dusting on the stipe or on caps below — Cortinarius spores are rust-brown, so mature gills take on a distinct rusty cast and a print is unmistakably brown. Lepista nuda has a bare stipe with no veil zone and a pale pink print.

Laccaria amethystina is deep purple throughout but far smaller and more slender, with thick, waxy-looking, widely spaced gills that are broadly attached, a fibrous twisted stipe, and a white spore print.

Lepista sordida is essentially a smaller, thinner-fleshed version with a more strongly hygrophanous, more pinkish-lilac cap; it favours grassy and disturbed ground. Lepista saeva, the Field Blewit, has a plainly greyish-brown cap with the violet confined to the stipe, and grows in pasture rather than woodland litter.

Mycena pura and its relatives are small, fragile and slender, with a translucent-striate cap margin, a hollow stipe and a white spore print.

Entoloma species can produce a pink print, but their gills turn a clear salmon pink, they lack any lilac tone, and their spores are angular in outline rather than warty ellipsoids.

A Working Checklist

Late autumn to early winter; deep leaf litter or compost; stout convex-to-flat cap fading from lilac to tan; crowded notched gills that peel cleanly from the cap flesh; lilac fibrillose stipe with a swollen mycelial base and no ring or cobweb zone; sweet perfumed odour; pale pinkish-buff spore print. Note that older books place this species in Clitocybe, so it also appears as Clitocybe nuda.