Entoloma hochstetteri Identification Guide

The Encounter

You find this species while walking slowly through damp native forest, usually with your eyes on the ground rather than the canopy. The setting is characteristic: deep leaf litter under southern beech or mixed podocarp and broadleaf forest, mossy banks along a track, the shaded cut face beside a walking route, or the sodden hollow between buttress roots. Rain has fallen recently, the litter is soft and the moss is swollen.

And then something is blue. Not blue-grey, not lilac, not steely — an indigo to sky-blue cone standing 4 to 7 cm high on a stalk of the same colour. No other detail is needed for the initial hit, because there is nothing else at that size and in that setting with that pigment. The colour comes from azulene-type compounds in the tissue and is at its most intense in young, fresh fruitbodies; a mushroom that has stood for several days fades toward dull green-blue, grey-blue or an olive cast, which is where beginners start to go wrong.

Fruitbodies occur singly, scattered or in small loose groups. They are slight, thin-fleshed and easily knocked over, so approach carefully and photograph the intact cluster before touching anything.

Reading the Cap

The cap is 1 to 4 cm across, and its shape is a genuine character. It begins conical, then expands to broadly conical or bell-shaped, and it retains a distinct pointed or sharply raised umbo at the centre almost throughout its life. It rarely flattens completely.

The surface is dry, not viscid, and it is radially fibrillose: under a hand lens you see fine silky fibres running from the umbo out to the margin, giving a streaked appearance and sometimes a faintly striate edge over the gills. The blue is deepest over the umbo and slightly paler toward the margin, and the fibrils often read as darker lines against a lighter ground.

The margin is thin, even and slightly incurved when young, becoming straight and sometimes minutely split with age. There is no veil, no ring zone and no fragments hanging from the edge at any stage.

Gills and the Colour Clock

The gills are the most informative part of this mushroom, because they change over time and the change tells you the genus.

In a young fruitbody the gills are pale bluish, blue-grey or nearly the cap colour, narrowly attached to the stalk — adnexed, sometimes with a small notch — moderately spaced, fairly broad and ventricose, with several tiers of short gills. As the spores mature, a pink to salmon or dull flesh-coloured wash spreads through them from the face outward, so that a mature cap has gills that are pink-and-blue in combination, and an old one has gills that are almost entirely salmon-brown with only a blue tint left along the edge.

That progression from blue to pink is not a curiosity; it is the visible arrival of the spore mass, and it is the single best confirmation that you are in Entoloma rather than in one of the small blue genera that keep white gills forever.

Stipe, Base and Flesh

The stalk is 3 to 7 cm long and 3 to 8 mm thick, equal or tapering slightly upward, hollow, and fragile. It is blue like the cap, sometimes a fraction paler, and its surface is longitudinally fibrous-striate: fine vertical fibres and sometimes shallow grooves, occasionally with a faint silvery sheen.

Excavate the base rather than pulling. At the foot you should find a small pad of white to bluish-white mycelium binding litter fragments and moss. There is no volva, no bulb, no sac and no ring anywhere on the stalk. The stalk splits lengthwise easily and cleanly, which is worth doing to confirm it is hollow rather than stuffed.

The flesh is very thin and pale bluish, whitish where thinnest. Cut a cap and a stalk and watch for two minutes: there is no bruising reaction, no colour change at the cut and no latex. Old fruitbodies fade overall rather than staining in a specific colour. The odour is faint and unremarkable, sometimes very slightly mealy.

The Spore Print and the Angular Spores

This is the step that converts a good guess into an identification. Cut a mature cap from its stalk, place it gills down on white paper, cover it with a glass or bowl to keep the humidity up, and leave it two to six hours. Because the fruitbody is small and thin it can dry out and stop dropping, so a humid chamber matters more here than with a fleshy mushroom.

The deposit is pink: a salmon, flesh-pink or pinkish-brown film. Against white paper the tone reads clearly. A white print, a rust-brown print or a purple-brown print all take you out of Entoloma immediately.

Under a microscope the spores are the clinching character for the genus. They are not smooth ellipsoids but distinctly angular, showing four to six flat facets and sharp corners in profile, roughly 10 to 12 by 7 to 9 micrometres, colourless individually and pink in mass. Angular spores plus a pink print is the definition of the genus, and no look-alike shares it.

Habitat, Forest Type and Season

The species is best known from New Zealand, on both main islands, in native forest, with morphologically similar collections reported from parts of Asia. It fruits from soil and deep leaf litter in shaded, humid native forest, notably under southern beech and in mixed podocarp and broadleaf stands, and it is characteristically found on mossy banks, damp track edges and gullies where moisture is retained.

The season is broadly summer through autumn in the Southern Hemisphere, from around November into June, with the best fruiting following sustained rain. Whether it is a litter saprotroph or forms a partnership with native tree roots is still not fully resolved, so record the trees around it: the association data is genuinely useful.

It does not grow on wood. A blue mushroom sitting on a fallen log with a disc-shaped attachment is something else, which brings us to the look-alikes.

Separating It From the Blue Look-alikes

Mycena interrupta is the classic confusion in the same forests. It is smaller, up to about 2 cm, with a hemispherical rather than conical cap that is viscid and translucent-striate, gills that are whitish or very pale blue and stay pale, a very thin stem attached to the substrate by a small flat basal disc, and a white spore print. Decisively, it grows on dead wood, mosses and bark, not from soil.

Blue and violet Cortinarius species are fleshier, have a cobwebby cortina between cap margin and stalk in youth, often show rusty fibres on the stalk where the cortina has collapsed, mature with rust-brown gills, and give a rust-brown spore print.

Waxcaps in Gliophorus and Hygrocybe can be blue-green in the same forests, but their caps and gills are viscid and waxy-thick, the gills are usually decurrent or broadly attached, and the print is white.

Other Southern Hemisphere blue Entoloma species genuinely exist. Separate them on stature, on how sharply pointed the umbo is, on gill attachment, and ultimately on spore dimensions; a pink print and angular spores tell you the genus but not the species.

Lilac and violet Lepista species are stockier, have flat or depressed caps rather than pointed cones, and produce smooth spores and a much paler pinkish print.