Date Waxcap Identification Guide

The setting matters as much as the mushroom

The Date Waxcap is a grassland species and a fussy one. Look in short, unimproved, species-rich turf that has never seen a plough or a nitrogen bag: old churchyards, ancient pasture on chalk or limestone, coastal cliff-top swards, dune grassland, upland hay meadows and long-established lawns. It is typically found alongside the wider waxcap community, so if you are already seeing scarlet and parrot waxcaps, earthtongues, coral fungi and pinkgills, you are in the right kind of ground.

Season is autumn, mainly late September into November, and the fruiting is brief. In most regions this is an uncommon species, and single finds of a handful of fruit bodies are the norm.

First impression

What catches the eye is a small dark cone standing proud of a very short sward, the shape almost architectural: a neat pointed tent of a cap on a slim upright stipe. From above the colour reads as date-brown to dark chestnut, occasionally almost blackish over the very centre. Against green turf that dark cone is surprisingly conspicuous once you have your eye in, and the shape alone narrows the field to a small group of conical waxcaps and a few pinkgills.

Then you turn one over, and the identification effectively resolves: the gills are a clean, bright yellow.

Reading the cap

Caps are roughly 2 to 6 centimetres across, occasionally to 8. They begin sharply conical, expand to broadly conical or bell-shaped, and retain an acute, well-defined umbo even in age. The margin often splits radially as the cap expands, and may lift or become irregular in old specimens.

Colour is a warm dark brown: date, chestnut or bistre over the disc, fading gradually to ochre-brown or tawny towards the rim. The surface is dry to faintly greasy in wet weather, never slimy or glutinous, and it is distinctly radially fibrillose, with fine silky innate fibres running from the umbo to the margin that give the cap a streaked look under a lens.

The critical negative character is that this cap does not blacken. Handle it, bruise it, leave it in the collecting box overnight, come back the next day: it stays brown. A whole group of similarly shaped waxcaps do exactly the opposite.

Gills

Here is the diagnostic contrast. The gills are pale to bright lemon-yellow or buttery yellow, sometimes with a slightly paler edge, and they sit under a dark brown cap. That colour clash is what the species is known for.

Structurally they are typical of the family: thick, broad, ventricose, widely spaced with lamellulae between, and adnexed to almost free at the stipe. They feel waxy or greasy when rubbed between finger and thumb and tend to smear or crumble rather than tear cleanly, which is the classic waxcap texture test. Some collections show faint interveining between the gills near the stipe.

Stipe, flesh and any colour change

The stipe runs about 4 to 10 centimetres long and half a centimetre to a little over a centimetre thick, cylindrical, often compressed or grooved lengthwise and sometimes twisted. It is dry, longitudinally fibrous, pale yellow to lemon-yellow along most of its length and whitish at the extreme base. There is no ring and no volva, and the interior becomes hollow with age.

Cut a fruit body in half. The flesh is thin, pale yellow in the stipe and yellowish to brownish immediately beneath the cap cuticle. Nothing dramatic happens: no reddening, no greying, and above all no blackening on the cut surface or at the bruised margin. The smell is faint and hard to characterise.

Taking a spore print

Waxcaps are brittle and their caps are conical, which makes a flat print awkward. The trick is to cut the stipe flush and rest the cap gills-down on white card supported by a small ring of rolled paper so the umbo does not tip it. Cover with a glass and leave it four to six hours somewhere cool and still. Hygrocybe caps dry out quickly, so a scrap of damp tissue under the cover helps.

The print is white. Under a lens the spores are smooth, thin-walled and ellipsoid. A white print rules out the pinkgills, which are the most plausible confusion by silhouette.

Substrate and ecology

This is a terrestrial grassland fungus, never on wood, and it grows in short turf with little litter and low nutrient status, usually where moss is present. Waxcaps as a group are now understood to be biotrophic, living in intimate association with grassland plants and mosses rather than simply rotting dead grass, which explains why they colonise so slowly and why they vanish from fertilised or reseeded ground. Their presence is used as an index of long-undisturbed grassland, and the Date Waxcap is regarded as one of the more demanding members of that community.

Separating it from look-alikes

The blackening waxcaps of the Hygrocybe conica group are the main confusion and the easiest to eliminate. They share the pointed conical cap, but their caps are scarlet, orange, olive-flushed or yellow rather than date-brown, and every part of them turns coal-black with age or handling, usually beginning at the margin and the stipe base. Old specimens are entirely black and unmistakable. H. spadicea stays brown throughout. The dune form, H. conicoides, behaves the same way but with orange-red tones and a habitat on fixed dunes.

Hygrocybe ovina is dark greyish-brown and might catch you at a glance, but its gills are grey-brown rather than yellow, its flesh reddens on cutting and it blackens in age.

Neohygrocybe nitrata and N. ingrata are dull grey-brown, with pale greyish gills, reddening flesh in ingrata and a strong nitrous smell, and never show the bright yellow gill colour.

Cuphophyllus colemannianus and its relatives have dull brownish caps but are convex rather than sharply conical, with strongly decurrent gills running well down the stipe.

Pinkgills, Entoloma species, include several dark conical grassland mushrooms, and some are genuinely similar in profile. Their gills develop a salmon-pink flush as the spores ripen and their spore print is pink, which settles it in a few hours.

Fibrecaps, Inocybe species, also produce brown radially fibrillose conical caps in grassy places, but their fibrils are coarser and often split the cap into shaggy strips, the gills are clay to dull brown rather than yellow, and the print is brown.

Finally, the bright conical waxcaps such as H. acutoconica have the right shape and yellow gills but a yellow to orange cap, not a dark brown one.

Field summary

Ancient short turf, autumn, sharply conical date-brown silky-streaked cap that refuses to blacken, thick widely spaced bright yellow waxy gills, yellow fibrous stipe, white spore print.