Cinnamon Webcap

The Cinnamon Webcap is a small, brightly gilled member of the Dermocybe group of Cortinarius, the pigmented webcaps whose fruitbodies carry yellow, orange or red anthraquinones. Where its relatives put that pigment into blood-red or deep orange gills, this species settles on a warm saffron to golden yellow, set below a soft cinnamon-brown cap.

It is a slender, delicate mushroom compared with the bulky Phlegmacium webcaps, and it fruits abundantly in the moss layer of damp conifer forest. The name has historically been applied rather broadly, and several closely related yellow-gilled species, in particular Cortinarius croceus, have been treated as forms of it at different times, so field records vary in their precision.

In common with all webcaps it has a cobwebby cortina in youth and a rusty brown spore deposit that progressively dulls the gill colour.

Cap

2-6 cm across, conical to convex when young, expanding to flat with a distinct low umbo. The surface is dry, matt and finely silky-fibrillose, coloured cinnamon-brown to yellow-brown, sometimes with olive tones, and usually a little darker at the umbo than at the margin.

Gills

Adnate to slightly emarginate, crowded and moderately broad, and bright saffron-yellow to golden orange when fresh, without red tints. Rusty spores dull them to cinnamon and finally rusty brown, but the yellow persists longest at the edges.

Stipe

3-8 cm long and slender, 3-8 mm thick, equal or slightly enlarged below, coloured yellow-olive to ochre-yellow and covered in fine paler yellow fibrils. The yellowish cortina leaves a vague fibrillose zone that catches rust-coloured spores, and yellow mycelium often binds the moss at the base.

Flesh & spore print

Flesh is thin and yellow to yellow-olive throughout, unchanging when cut. The spore print is rusty brown; spores are small, ellipsoid to almond-shaped and finely warted.

This webcap grows in damp coniferous woodland, particularly with Norway spruce and pines, and extends into wet birch woodland and bog margins on acid peaty ground. It is a species of mossy places, fruiting gregariously through Sphagnum, feather mosses and thin needle litter, and often appearing in loose scattered troops of many fruitbodies.

The season is late summer to autumn. It is widespread and common through the boreal and montane forests of Europe, including Scandinavia, the Alps, Scotland and northern England, and occurs across the northern conifer belt of North America and Asia.

Cortinarius cinnamomeus is ectomycorrhizal, forming mantles and Hartig nets on the fine roots of spruce, pine and birch. On the waterlogged, acid, nutrient-poor peats where it is most abundant, the fungal partner substantially improves the host tree's ability to capture nitrogen and phosphorus locked up in slowly decaying organic matter.

Its yellow anthraquinone pigments are shared with several relatives and have made the Dermocybe webcaps a traditional source of natural wool dyes. Ecologically the pigments are thought to discourage invertebrate grazing on the gills, the tissue where spores are produced. The mycelium is perennial, spreading gradually through the moss carpet, and fruiting follows sustained autumn rain.

Cortinarius croceus is extremely close and often treated as a variant: it tends to have a more olive-brown cap and duller ochre-yellow gills, sometimes with a faint reddish flush. Cortinarius semisanguineus shares the olive-tawny cap but has vivid blood-red gills.

Cortinarius malicorius has deeper orange gills and an orange veil zone toward the stipe base, and Cortinarius sanguineus is blood-red throughout. Small tawny Gymnopilus species can look similar but have no cobwebby cortina and a brighter orange spore deposit.