Contrary Webcap Identification Guide

The Moment of Recognition

The Contrary Webcap tends to announce itself in a mature spruce forest on limey ground, in the second half of autumn, when the moss is soaked and the light under the canopy is flat and green. What you see first is a troop of chunky, solid mushrooms with caps the colour of apricot jam or warm ochre-orange, sitting low over the moss on obviously thick, white, club-footed stems. The contrast between a warm-toned cap and a chalk-white stipe is visible from several metres away, and it is the first hint that you are not looking at one of the endless dull brown webcaps.

Pick one, turn it over, and the species earns its English name. Under an orange cap you find gills of a clear violet, blue-lilac or amethyst tone. Nothing about the top of the mushroom prepares you for the colour underneath, and that deliberate mismatch is the single most memorable field character of the species.

Getting to the Genus First

Before chasing the species, settle the genus, because it removes hundreds of candidates. Cortinarius fruit bodies carry a cortina: a veil of fine silky threads, like a scrap of spider web, stretched from the cap margin to the stipe in young buttons. As the cap expands the cortina tears and collapses onto the stipe, where it forms a faint fibrillose zone rather than a proper ring. Within a day or two, rust-brown spores settle onto that zone and stain it a distinct rusty band - so on a mature specimen you look for a rusty girdle on an otherwise white stem, not for a membranous ring.

Find a young button in the troop if you can. On Cortinarius varius the cortina is white and copious, and its remnants often hang as fine fibrils from the cap margin as well.

Reading the Cap

A full-grown cap is 4 to 12 centimetres across, sometimes larger on rich ground. It starts strongly convex, almost hemispherical, and flattens out with a broad low umbo and a margin that becomes wavy and often slightly irregular in age. The margin is inrolled and rather thick when young, which contributes to the stocky overall impression.

The surface is viscid to glutinous in wet weather and takes on a varnished shine as it dries. Because of that slime layer, mature caps almost always collect a mosaic of stuck-on spruce needles, moss fragments and litter, and part of the field routine is wiping the cap clean with a thumb to see the real colour. Underneath the debris the colour is ochre-orange, warm tawny, apricot or clay-orange, generally deeper at the centre and paler, sometimes almost buff-cream, at the margin. The cap skin peels partway from the margin. There are no scales, no felt and no obvious fibrils - the pellicle is smooth.

The Gills, Stage by Stage

Gill colour changes through the life of the fruit body, so you must judge it against age. In an unopened or barely opened button the gills are a saturated blue-violet to lilac, and this is the diagnostic phase. As the cap flattens, clay and cinnamon tones invade the violet as the spores mature, and by the time the cap is fully flat the violet has usually gone entirely, leaving warm rust-cinnamon gills with perhaps a lilac ghost at the extreme edge or in the deepest recesses near the stipe.

Structurally the gills are crowded, fairly narrow, and emarginate - notched where they meet the stipe, with a short tooth running down it. Gill edges are minutely uneven and often stay a shade paler than the faces. If every mushroom in your troop is fully expanded and rusty, dig for a small button before concluding the gills were never violet.

Stipe, Base and Flesh

The stipe is 5 to 10 centimetres tall and 1 to 2.5 centimetres thick at the apex, solid and firm right through, dry, and pure white or with the faintest cream tinge. The base swells into a club - a smooth, evenly thickened clavate foot up to 3 or 4 centimetres wide - but crucially it is a rounded club, not a bulb with an abrupt rim or a marginate flange around the top. That distinction does a great deal of work in this genus.

Slice the whole fruit body lengthways. The flesh is white, thick and firm in the cap, white through the stipe, and it does not change appreciably on exposure to air. There may be a very faint violet blush at the extreme apex of the stipe in young specimens, but the body of the flesh stays white rather than turning yellow, lilac or purple. Odour is faint and unremarkable. If your fruit body has yellow flesh, lilac flesh, or flesh that discolours strongly when cut, you are in a different Phlegmacium.

Taking a Spore Print

Cut the cap free, set it gills down on white paper under a cup, and leave it four to six hours. The deposit is a strong rust-brown to ochre-brown - unmistakable and easy to read on white. In the field the same information is available for free: look for rusty dusting on the cortina zone and on the caps of neighbouring specimens lower in the troop.

Under the microscope the spores are almond-shaped to lemon-shaped, coarsely warted, and roughly 10 to 14 by 6 to 8 micrometres. A drop of strong alkali on the cap skin turns it reddish-brown to purplish-red, a useful confirmatory bench test if you keep reagents.

Substrate, Partner Trees and Season

Cortinarius varius is mycorrhizal - it forms root partnerships with trees and cannot be grown on wood or litter. Its principal partner is Norway spruce, with fir a frequent alternative, and it strongly prefers calcareous or at least base-rich soils, so think chalk and limestone spruce plantations, montane forest and alkaline sandy woods rather than acid peaty ground. Fruiting runs from late summer into late autumn, peaking in October across much of temperate Europe.

It usually appears gregariously, in loose troops, arcs or partial rings through moss and needle litter, and a productive patch will fruit year after year once you have found it.

Separating It From the Other Big Webcaps

Work through the near neighbours on structure alone.

Cortinarius multiformis and Cortinarius allutus share the stocky build, viscid ochre or honey cap and pale stipe, but their young gills are whitish to pale clay and never violet, and their bulbs tend to be more abruptly rimmed.

The Cortinarius calochrous and Cortinarius dibaphus groups do have violet young gills, but they carry a marginate bulb - a flattened bulb with a distinct rim or gutter running round its upper edge - and their flesh is usually tinted yellow or lilac rather than pure white. Cap tones there run more yellow-ochre or olive.

Cortinarius caerulescens has a blue to violet cap as well as violet gills, so the contrast that defines the Contrary Webcap is absent. Cortinarius largus is lilac in both cap and gills and grows with broadleaf trees. Cortinarius cumatilis has a whitish to pale lilac viscid cap but whitish gills.

Cortinarius traganus can look superficially similar in a mossy conifer wood, but its cap is dry and silky-fibrillose rather than viscid, the whole fruit body is washed lilac, and its flesh is marbled ochre-brown with a pungent smell.

Finally, do not be diverted by boletes or by Tricholoma species with orange-brown caps: the rust-brown print and the cobweb veil settle the matter.

The Short Version

Stocky build, viscid ochre-orange cap, violet gills in youth turning rusty, solid dry white clavate stipe with a rusty cortina zone, white unchanging flesh, rust-brown print, spruce on limey ground in autumn. Get a button and a mature cap into the same hand and the species reads itself.