Red Banded Webcap

The Red Banded Webcap is among the easiest webcaps to name in the field, thanks to a feature no other common species matches: a series of vivid cinnabar to brick-red bands wrapped like bracelets around the lower stipe. These are remnants of a coloured outer veil, quite separate from the cobwebby cortina that all Cortinarius species carry between cap margin and stipe when young.

It is a large, solid fungus by webcap standards, with a broad brick-red-brown cap and a swollen stipe base, and it belongs to the group of Cortinarius known as the telamonias, dry-capped species whose flesh is hygrophanous and changes tone as it dries. Among these mostly drab brown species it is a striking exception.

The species is a birch specialist across the northern hemisphere and is one of the most familiar large fungi of boreal and upland birch woodland, often fruiting in numbers where mosses and bilberry carpet the ground.

Cap

Large for the genus at 5-12 cm across, convex to bell-shaped when young and expanding to broadly convex or flat with a low umbo. The surface is dry and radially fibrillose, sometimes finely scaly at the disc, coloured brick-red to reddish tan or warm date-brown, paler and buffer at the margin, where fine whitish veil fibres may hang in young specimens.

Gills

Adnate and moderately broad, fairly well spaced, pale clay to cinnamon-buff at first and darkening through cinnamon to rusty brown as spores ripen. The gill edges stay a little paler and slightly ragged.

Stipe

Stout and imposing, 8-15 cm long, thickening downward to a club-shaped or bulbous base. The ground colour is whitish to pale tan, and around it run two to five conspicuous cinnabar-red to orange-red belts, the remains of a coloured outer veil. Above them the whitish cortina leaves a rust-dusted zone.

Flesh & spore print

Flesh is pale buff to whitish, watery brown in wet weather and paler as it dries, unchanging when cut. The spore print is rusty brown, with almond-shaped, warted spores.

This webcap is tied to birch and is found wherever birch grows on damp, acid, nutrient-poor ground: heathy birch woodland, boggy birch carr, the edges of moorland and the birch fringes of conifer plantations. It fruits singly or in scattered troops among mosses, bilberry and heather, and is common in Sphagnum-rich hollows.

The season is late summer through autumn. It is widespread and often abundant across northern and upland Europe, including Scandinavia, Scotland and northern England, and occurs across the boreal and northern temperate zones of North America wherever birch is present.

Cortinarius armillatus is an ectomycorrhizal symbiont of birch. Its hyphae enclose the tree's fine roots in a mantle and form a Hartig net between the outer cells, exchanging soil-mined phosphorus, nitrogen and water for photosynthetic sugars. Birch on peaty, acid or waterlogged soils relies heavily on such partners, and this species is a mainstay of that community.

The mycelium persists year-round in the humus and moss layer, spreading outward from colonised roots. Fruiting is triggered by autumn rain and cooling temperatures, and the large fruitbodies release enormous quantities of rust-coloured spores that dust the surrounding litter. Discarded and decaying fruitbodies are themselves fed on by fungus gnats, beetle larvae and slugs.

Cortinarius paragaudis is very similar in shape but grows with conifers and has narrower, duller reddish belts on a more slender stipe. Cortinarius triumphans also carries stipe bands, but they are yellow to ochre rather than red, and its cap is viscid and golden-yellow rather than dry and brick-red.

Cortinarius rubellus is a much smaller, slimmer conifer species with a sharply pointed cap and pale yellow rather than red girdles. Large brown Cortinarius of the telamonia group, such as C. bivelus, share the birch habitat and hygrophanous cap but have whitish rather than red veil remnants on the stipe.