Cortinarius rubellus Identification Guide

The Setting and the First Glance

Cortinarius rubellus is a fungus of damp, mossy, acidic conifer forest, and the setting does half the identification for you. Picture deep spruce or pine woodland where the ground is a continuous carpet of feather moss and bilberry, with sphagnum in the wetter hollows and boggy margins. It fruits from soil among the moss, often with only the cap and the top of the stipe showing while the lower half is buried in the moss layer. Because of that, the first impression is of a small, sharply conical, rusty-orange cone standing above green moss, sometimes singly, sometimes as a scattered troop across several square metres. The proportions are noticeably elegant: this is a tall, slim fungus rather than a squat one, and the stipe is often longer than you expect once you tease it out of the moss. Always extract it whole. Pulling the cap off and leaving the stipe base behind loses the best characters.

Reading the Cap

The cap measures 3 to 8 centimetres across. It starts as a distinctly conical or bluntly bell-shaped button and expands only partly, so that even mature caps keep an obvious raised centre. That centre is the key: a sharp, narrow, sometimes almost nipple-like umbo, quite different from the low dome of related species. The margin is inrolled at first and often stays slightly downturned, and it may be finely fringed with pale veil fibres in young material. The surface is dry at all times, matt and finely matted-fibrillose, breaking into small appressed scales or fibrillose streaks towards the disc so that it looks minutely tousled under a lens. Colour is a warm foxy orange-brown to rusty red-brown, usually a little darker and more saturated in the centre and fading slightly outwards. It does not become sticky when wet, and it does not develop the pale drying zones of a hygrophanous cap.

The Gills and the Cobwebby Veil

Underneath, the gills are thick, broad, and clearly spaced apart, attached adnately to notched at the stipe. Count them and you will find comparatively few for the size of the cap. Their colour begins pale ochre to clay or dull saffron and matures to a strong rusty cinnamon as spores accumulate, sometimes with a slightly paler even edge. Young specimens show a pale cobwebby cortina stretched between cap margin and stipe like a fine spider web. This is the genus signature. It never forms a membranous skirt. Instead it collapses and leaves scattered fibrils on the stipe, and where spores catch in them a rusty band appears. Check the upper stipe for that rusty fibrillose staining even when the cortina itself has vanished.

Stipe, Girdles and Base

The stipe is the character that seals the identification. It is 5 to 12 centimetres long, sometimes more when drawn up through moss, and only 0.5 to 1.5 centimetres thick, cylindrical or tapering slightly downwards and occasionally with a slightly swollen base. The ground colour is paler than the cap, ochre-yellow to pale tawny with a silky sheen. Over that ground colour lie one to several distinct girdles: irregular transverse belts or chevrons of yellow to bright ochre veil fibres, wrapping the stipe like fading bands on a rope. They may be sharp and clean or partly smeared, but they are almost always detectable, and they are yellow rather than white or red. There is no volva, no marginate bulb and no membranous ring. The base is often clothed in yellowish mycelium binding moss and needles.

Flesh and Colour Change

Slice a fruiting body from cap centre to stipe base. The flesh is pale yellowish to ochre-yellow, thin in the cap and more fibrous in the stipe, and it is essentially unchanging. There is no blue, green or red reaction on cutting, and only a slow, dull rust-brown darkening of exposed or handled surfaces after some time. The smell is weak, a little earthy or faintly radish-like, and never strongly floral, mealy or aromatic. The absence of a sharp colour change is itself informative, since several superficially similar orange woodland fungi bruise conspicuously.

Taking a Spore Print

Select a fully open cap that is still firm, cut the stipe flush with the gills, and lay the cap gills-down on white paper with a slip of dark card underneath one half. Cover with a glass or bowl and leave it in a still, room-temperature spot for six to twelve hours. Expect a heavy rust-brown to cinnamon deposit, warm and bright rather than dull chocolate or greyish. That colour, combined with the cortina, is what confirms the genus Cortinarius. Microscopically the spores are broadly ellipsoid to almond-shaped, 8 to 12 by 6.5 to 8.5 micrometres, and covered in coarse warts.

Substrate and Season

This species is ectomycorrhizal with conifers, above all Norway spruce and pine, and it favours damp acidic soils rich in moss and organic matter. It is characteristic of northern and montane forests and appears in upland conifer plantations further south. Fruiting runs from late summer into late autumn, peaking after sustained wet weather. It is a soil-dweller, so a fruiting body apparently arising from a rotten log almost always turns out to be rooted in the soil or moss beneath it. Association with bilberry, sphagnum and dense feather moss is a strong contextual clue.

Separating the Closest Look-alikes

Cortinarius orellanus shares the foxy colouring but grows with broadleaved trees, is stockier and broader in proportion, has a low broad umbo instead of a sharp point, and has a stipe that lacks crisp yellow belts.

Cortinarius armillatus is much larger and more robust, grows with birch, and carries several vivid brick-red to orange-red girdles on a stout stipe. Red bands rather than yellow ones, and a bigger, duller, more brown cap, distinguish it easily.

Cortinarius gentilis is smaller and slimmer with a thin stipe bearing yellow veil bands, but its cap is darker date-brown with a narrower umbo and its gills are relatively narrower and more crowded.

Cortinarius limonius has a brighter, more lemon-yellow to orange cap and yellower flesh, with a less pronounced pointed umbo and weaker banding.

Cortinarius cinnamomeus has bright saffron to blood-orange gills contrasting with an olive-brown cap and a thin unbanded yellow stipe.

Galerina and Gymnopilus species can look similar in colour, but Galerina species are typically hygrophanous with striate margins and grow on moss or rotten wood, while Gymnopilus species grow directly from wood and have brighter yellow flesh.

Field Checklist

• Sharp conical umbo persisting on the expanded cap
• Dry, matted-fibrillose, foxy orange-brown surface
• Thick, distant gills ripening rusty cinnamon
• Slender stipe with distinct yellow to ochre transverse girdles
• Cobwebby cortina and a rust-dusted fibrillose zone, no true ring
• Rust-brown spore print
• Moss and bilberry under spruce or pine, late summer to late autumn