Big Blue Pinkgill Identification Guide

The moment you find one

A Big Blue Pinkgill is almost never a woodland find. The setting is short, hungry turf: an old churchyard, a sheep-cropped down, an ancient lawn, a dune slack, a mossy pasture that has never seen a plough or a bag of fertiliser. These are the same swards that produce waxcaps, earthtongues and clavarioid corals, and the Big Blue Pinkgill belongs to that same guild of grassland specialists.

What stops you is the colour. Deep indigo, steel-blue or blue-grey is genuinely rare in a fleshy agaric, and from several paces away the impression is of something solid and heavy sitting low in the grass rather than a slender toadstool perched on it. Handle it and that impression is confirmed: it is thick-fleshed, firm and surprisingly weighty for its size.

Reading the cap

The cap runs roughly 5 to 12 cm across, occasionally larger. It starts strongly convex, sometimes almost bun-shaped with the margin rolled tightly under, and slowly flattens, often keeping a broad low umbo at the centre. The surface is dry to slightly greasy in wet weather, matt or faintly silky, and typically shows fine radial fibrils or streaking when you catch it in low light.

Colour is the trap. Fresh young caps are convincingly blue-violet or slate-blue. As they age the blue drains away from the centre outwards, passing through grey-blue to dull ochre-brown or straw, so a mature cap may show only a blue tinge at the margin, and a very old one may show none at all. Older caps can also crack into fine areolate patches at the disc. If you find several fruitbodies, always read the youngest for colour and the oldest for shape.

Gills, and the pink that gives the group its name

Turn the cap over. The gills are fairly crowded, moderately deep, and attached in a sinuate (notched) way, sometimes with a tiny decurrent tooth running onto the stem. When young they are white, pale grey or faintly blue-tinged along the edge. As the spores ripen they flush a clear salmon or dusty pink, and that flush is the entire diagnosis of the genus, so give young material time or find an older cap alongside it.

The gill edge is usually even, occasionally minutely uneven under a lens. The gill trama is fragile and the blades break easily against a thumbnail. There is no cobwebby veil between margin and stem at any stage, and no film of tissue ever bridged the gap.

The stipe and base

The stem is stout for the size of the cap: 4 to 10 cm tall and often 1 to 2.5 cm thick, cylindrical or slightly thickened downwards, sometimes flattened or grooved. Its ground colour repeats the cap in a paler key, blue-grey to lilac-grey, overlaid with silky white longitudinal fibres that make it look streaky and silvered. The apex is usually palest.

Dig, do not pull. At the base you should find white mycelial down binding soil and moss, but nothing more structured. There is no ring, no ring zone, no sheath and no bag-like volva. If any of those are present you are not in Entoloma.

Flesh and cut surfaces

Slice the fruitbody from cap to base. The flesh is white, firm and thick, often with a thin blue-tinged layer immediately under the cap cuticle. It does not blue, redden, blacken or exude anything when cut, and bruising the gills produces no dramatic reaction, which is itself a useful negative character. The smell is farinaceous, that mealy note between fresh flour and cut cucumber, strongest when the flesh is crushed between the fingers.

Taking and reading a spore print

This species repays a print because pink is easy to imagine and hard to be sure of on the gills alone. Cut a mature cap free of its stem, lay it gill side down on white paper or, better, half on white card and half on clear glass, cover with a cup to stop draughts, and leave it for four to eight hours somewhere still.

Read the print in daylight. Scrape the deposit into a low ridge with a knife edge before judging it, because a thin dusting always looks paler and duller than the true colour. Entoloma gives a definite salmon or brownish pink, quite unlike the pale flesh-buff of a blewit. Under a microscope the spores are angular in outline, with five to eight straight facets, and that heterodiametric angularity is the family signature.

Substrate and season

The Big Blue Pinkgill fruits from late summer into late autumn, roughly August to November, with a peak after the first substantial autumn rains. It grows on the ground in nutrient-poor, moss-rich, closely grazed or mown grassland, most often over chalk, limestone or other base-rich soils, and occasionally in open woodland margins on the same geology. It appears singly, in twos and threes, or in loose arcs, and it tends to reappear in the same square metre year after year, so a mapped site is worth revisiting.

It is one of the classic indicators of grassland that has been undisturbed for a very long time. Ploughing, reseeding and fertiliser all remove it, and it does not colonise improved leys.

Separating it from the look-alikes

Wood Blewit (Lepista nuda). The commonest confusion. The blewit is lilac to violet-brown rather than blue, the colour runs through gills and stem as well as cap, the cap is smoother and more hygrophanous, and it lives in leaf litter and compost heaps in woodland rather than in old turf. Decisively, its spore print is a pale pinkish buff, much weaker than the salmon of a pinkgill, and its spores are finely warted ellipsoids rather than angular.

Blue Cortinarius, for example C. caerulescens. Young fruitbodies carry a cobwebby cortina from cap margin to stem, and traces of it usually remain as a rusty-dusted band on the stipe. The gills go rust-brown, the print is rusty ochre, and the base is often a marginate bulb. Habitat is woodland, typically with beech on chalk.

Small blue pinkgills such as Entoloma chalybaeum, E. serrulatum and E. nitidum. These share the pink print but are altogether slighter: caps under 4 cm, thin-fleshed, often fibrillose-scurfy and much darker blue-black, with slender hollow stems. E. serrulatum has a dark-dotted, finely toothed gill edge visible with a lens. Bulk of flesh is the quickest separator.

Blue-grey Tricholoma and Clitocybe species. White spore print, and either sinuate gills with no pink flush or strongly decurrent gills. A print settles it in an afternoon.

Within the Big Blue Pinkgill complex itself. Several closely similar taxa have been split out, differing in the depth of blue on the stipe, whether the cap fades to ochre or to grey, and in microscopic detail. Record cap colour of the youngest specimen, stipe colour, and substrate geology in your notes so a determination can be revisited later.

Field checklist

Stout blue to blue-grey cap fading ochre; sinuate crowded gills turning salmon; fibrillose blue-grey stem with silky white streaks; white unchanging flesh; mealy smell; no ring and no volva; salmon pink spore print; old unimproved grassland in autumn.