Big Blue Pinkgill

The Big Blue Pinkgill is the heavyweight of the blue Entoloma. Where the small Leptonia species are slender and fragile, E. bloxamii is fleshy and solid, with a broad indigo to steel-blue cap and a thick stipe, and it is one of the most sought-after finds of European grassland mycology.

It is a scarce species tied to ancient, unimproved, usually calcareous grassland, and it is red-listed in a number of countries. Recent taxonomic work has split several closely related blue taxa out of the older broad concept of E. bloxamii, including Entoloma madidum and segregates in the bloxamii complex, distinguished mainly on spore size and habitat.

Despite the taxonomic complexity, the field impression is consistent: a substantial mushroom with the build of a Tricholoma, coloured deep blue, sitting in short downland turf.

Cap

The cap is 4-10 cm across, convex then broadly flattened, often with an irregular or wavy margin and sometimes a shallow central depression. Colour is deep steel-blue, indigo or blue-grey when young, fading with age from the centre to buff-brown or ochre-blue. The surface is dry, silky-fibrillose to slightly innately streaked, not viscid.

Gills

Gills are sinuate to adnexed, moderately crowded, thick and rather broad. They begin whitish, sometimes with a faint bluish tinge, then flush pink and finally dull salmon as the spores ripen. Edges are even, not serrated or differently coloured.

Stipe

The stipe is stout, 4-9 cm tall and 1-2.5 cm thick, solid, fibrous, longitudinally striate and blue to blue-grey, often paler and whitish at the base. It lacks a ring, a volva and any basal bulb.

Flesh and spore print

The flesh is firm and white, sometimes bluish under the cap cuticle, without marked colour change when cut. The smell is farinaceous. The spore print is pink, and the spores are angular in outline.

Big Blue Pinkgill occurs in short, unimproved grassland on calcareous or base-rich soils: chalk and limestone downland, old grazed pasture, coastal grassland over shell sand and, occasionally, long-established churchyards and lawns. It grows among mosses in swards with a rich waxcap flora.

Fruiting is from late summer into autumn. The species is thinly distributed across Europe, notably in Britain, and is reported from North America. Populations are small and localised, with only a few fruitbodies appearing at a site in a given year, and it may be absent for several seasons before reappearing in the same spot.

Like other grassland Entoloma, its nutritional strategy is not fully resolved; the species behaves as a member of the waxcap guild, dependent on ancient, unfertilised turf and its intact moss and root layer, whether through saprotrophy in that layer or a biotrophic link with plants.

It is one of the highest-scoring indicator species in grassland fungus surveys precisely because it does not tolerate ploughing, reseeding or nutrient enrichment. The perennial mycelium can occupy the same small area of turf for decades, so a recorded site is worth revisiting even after blank years.

Entoloma madidum and other members of the bloxamii complex are very similar, differing largely in spore dimensions and sometimes in habitat, with woodland-associated segregates recognised by some authors. Field separation is often impractical.

The small blue Leptonia such as Entoloma chalybaeum and Entoloma serrulatum share the blue colouring but are far more slender, with thin hollow stipes and umbilicate scurfy caps, and E. serrulatum has serrated blue-black gill edges. Blue Cortinarius species of woodland have a cobwebby veil, rusty-brown gills at maturity and a rusty spore print, and blue Lepista species such as the Wood Blewit have pinkish-buff spore prints, crowded gills and a woodland litter habitat rather than short downland turf.