Viscid Violet Cort Identification Guide

First Impression and Setting

Viscid Violet Cort is a summer mushroom of eastern North American hardwood forest, and what registers first is a purple cap with a wet shine. On a humid July morning in an oak wood, the caps look varnished, and rain or dew beads on them. Pick one up and your fingers stick slightly, which is the character the name is built on.

The habitat is broadleaf woodland, above all with oak, and often on slopes, along path banks and in leaf litter under mixed hardwoods. It appears from early summer into early autumn, earlier in the year than most of the big autumn webcaps, and usually in small scattered groups rather than singly.

The second thing to notice is that the purple is not uniform. Mature caps almost always develop pale yellowish, whitish or buff spots, blotches and radial streaks, particularly toward the centre, so the cap reads as violet fading and breaking up rather than solid purple.

Reading the Cap

Caps are three to eight centimetres across, convex at first, then broadly convex to flat, sometimes with a low broad hump.

Texture is decisive. The surface carries a distinct layer of gluten and is slimy or sticky in any damp weather, drying to a shiny, slightly tacky varnish in a dry spell. Litter and small debris stick to it. There is no felting, no scurf and no upturned fibrils.

Colour begins a fairly bright violet to purple, sometimes with a bluish cast at the margin, and fades unevenly with age and sun toward lilac-buff. The yellowish or whitish spotting develops as it fades and is one of the most useful field marks. Peel the cap edge with a thumbnail: the gluten strips as a thin, transparent skin.

The Gills

Gills are attached to the stem with a notch, moderately close, and moderately broad.

Colour sequence matters. They begin pale violet or lilac, distinctly paler than the cap and much paler than the near-black gills of the dry violet webcap. As the spores mature they turn a dull cinnamon then rusty brown, often keeping a faint violet tint on the edges longest. On a mature specimen the gills are essentially rust-coloured with a lilac ghost at the margin.

The change in gill colour with age is one reason people fail to match a find to a photograph. Always look for the youngest specimen in the group before judging gill colour.

The Veil

On young buttons, look for the cortina: a fine, silky, cobweb-like veil of pale violet threads bridging the cap margin and the stem. It is delicate and vanishes quickly once the cap expands.

What remains is a faint fibrillose zone on the upper stem, and because falling spores lodge in it, that zone soon becomes rust-brown. On this species there is also a glutinous universal veil, so the stem can carry sticky, slightly slimy bands or a smeared, viscid coating that dries to thin shiny patches. Confirming that the mushroom had a cobweb veil, not a membranous ring, is the step that places it in Cortinarius.

The Stipe, Base and Flesh

Stems are four to ten centimetres tall and up to about a centimetre and a half thick, more or less equal but usually swelling into a club-shaped base.

The surface is whitish to pale violet, often more strongly violet toward the apex, and is viscid or sticky when fresh from the glutinous veil, particularly in the lower half. It is smooth rather than fibrillose-woolly.

Dig the base out carefully. There is no volva, no rim and no sac; you should find a club-shaped foot in litter with pale mycelial threads attached.

Slice the mushroom lengthways. The flesh is white to pale lilac, thickest in the cap centre, and usually shows the most violet in the stem apex and just under the cap skin. It does not change colour appreciably on cutting, and there is no latex. The smell is faint and unhelpful.

Taking a Spore Print

Cut the stem flush, place the cap gill-side down on white paper, cover it and leave it several hours. The print is rust-brown to cinnamon-brown, the standard Cortinarius result, and it is the character that rules out lookalikes with pale prints.

Under the microscope, spores are ellipsoid to almond-shaped and roughly warted, in the region of eight to twelve by five to seven micrometres. Spore measurements are the practical route to separating this species from its very close relative described below, so it is worth recording them if you have a scope.

Substrate and Season

Fruit bodies grow from soil and leaf litter in hardwood forest, never from wood, and the fungus lives in mycorrhizal partnership with tree roots, with oak the most frequent partner. The season is early summer through early autumn in the eastern United States and adjacent Canada, driven by warm humid rain. Note the trees overhead as part of the record; a find under pure conifer would point elsewhere.

Separating It from the Look-Alikes

Cortinarius iodeoides is the closest relative and is essentially identical in the field, with the same slimy purple cap and yellow spotting. Separation rests on microscopy, where its spores average slightly smaller. Field records are often best given as the iodes group.

Violet Webcap, Cortinarius violaceus, is much darker, a solid blackish-violet, with a dry, matte, scurfy cap covered in fine upturned fibrils, deep purple-black young gills, and a stouter club-shaped violet stem. Wet fingers versus dry felt is the quickest test.

Cortinarius salor and similar viscid violet species in the same broad group share the slimy cap but differ in shades and in the extent of pale spotting; several are separated on microscopy.

Amethyst Deceiver, Laccaria amethystina, is dry, smaller, with thick widely spaced gills, no veil, and a white spore print.

Wood Blewit, Clitocybe nuda, is fleshier, with a smooth moist rather than glutinous cap, crowded lilac gills, no cobweb veil, and a pinkish-buff print.

Young purple Russula species can have a shiny cap but have brittle, crumbly flesh that snaps like chalk, no veil, and pale cream to white prints.

A Field Checklist

Sticky or slimy violet cap developing yellowish spots and streaks; pale violet gills maturing rusty; cobweb veil leaving a rust-stained zone; viscid whitish-violet club-based stem; white to lilac unchanging flesh; rust-brown spore print; soil under oaks in summer.