Blue Edge Pinkgill
Entoloma serrulatum
Also called saw-gilled leptonia, blue-edge entoloma, serrated pinkgill
A small dark blue-black grassland pinkgill whose pale gills carry a finely serrated blue-black edge visible with a hand lens.
Overview
The Blue Edge Pinkgill is a small member of Entoloma section Leptonia, the group of slender, often blue or violet pinkgills of old grassland and heath. It is dark, almost inky in colour when fresh, and stands out against green moss and turf.
Its defining feature is microscopic in scale but visible in the field with a hand lens: the gill edges are finely toothed or saw-like and coloured a distinct blue-black, standing out sharply against the paler grey-pink gill faces. This character, reflected in the epithet serrulatum, separates it from its blue relatives.
Like other Leptonia of unimproved turf, it appears in autumn in grasslands that also support waxcaps, earthtongues and other slow-colonising fungi, and it is used as an indicator species in survey work.
How to identify it
Cap
The cap is 1-4 cm across, convex then flattened and usually distinctly depressed or umbilicate at the centre. The colour is dark blue-black, blackish-blue or steely blue-grey, fading with age towards brownish-grey. The surface is dry and minutely scurfy or fibrillose-scaly, especially at the disc, and often faintly striate at the margin when moist.
Gills
Gills are adnate to slightly emarginate, moderately spaced, and pale grey to whitish before flushing pink as the spores ripen. The critical character is the edge: finely serrated and stained dark blue to blue-black, giving a two-tone effect that a hand lens shows clearly.
Stipe
The stipe is 2-6 cm tall, slender, cylindrical, hollow, smooth to finely fibrillose and steely blue to blue-black, often paler and greyer near the apex, with a white-downy base. There is no ring or volva.
Flesh and spore print
The flesh is thin, bluish-grey to greyish, with no marked colour change on cutting and no distinctive smell. The spore print is pink, and the spores are angular in the usual Entoloma pattern.
Where and when it grows
Blue Edge Pinkgill fruits in short, unimproved grassland, mossy turf, heathy pasture and occasionally in damp grassy woodland edges and dune grassland. It shows a preference for acidic to neutral, moss-rich, nutrient-poor swards and is frequently found in the same fields as waxcaps.
The season runs from late summer into autumn. It is widespread but local across Europe and is also recorded from North America. Fruitbodies usually appear singly or in scattered small groups among moss, and their dark colours make them easy to miss against wet turf.
Ecological role
The species is a grassland fungus of long-established turf. As with other Leptonia, its precise nutritional mode is debated, with evidence for saprotrophic activity in the moss and root layer alongside indications of a closer relationship with living plants or bryophytes. Practically, it behaves like the waxcap guild, requiring undisturbed, unfertilised ground.
Mycelium persists for many years and fruits in autumn flushes after rain. Because the species disappears from improved grassland, it contributes to grassland quality scores in fungal survey protocols in several European countries.
Similar species
Entoloma chalybaeum is the nearest relative, with similarly dark blue caps and stipes, but its gill edges are concolorous with the faces rather than serrated and blue-black. A hand lens on a fresh gill edge is the quickest way to separate them.
Entoloma corvinum has a blue-black fibrillose cap but a white or whitish stipe base and paler gill edges, while Entoloma incanum is olive-brown capped with a bright green stipe and a mouse-like smell. Blue Mycena and Marasmius species are white-spored, and dark grassland Inocybe have rusty-brown spore prints and radially fibrous caps, so a pink print rules them out.