Violet Webcap Cortinarius violaceus — a strikingly dark, velvety-capped Cortinarius found across Pacific Northwest forests
The violet webcap is one of the few Pacific Northwest mushrooms that is deep violet to nearly black all over — cap, gills and stem alike. The cap is dry and covered in small upright tufts of hair that give it a rough, velvety look, and the stem often thickens into a swollen, club-shaped base. As in every Cortinarius, a cobwebby cortina rather than a true partial veil covers the young gills, which darken to rusty brown as the spores mature on them (Siegel & Schwarz).
Cortinarius is a huge genus that includes several deadly poisonous species. This page covers identification; see Edibility below for why we don’t recommend eating this one, or any webcap.
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Identification
| Feature | Description |
|---|---|
| Cap | 4–13 cm across, rounded at first and flattening with age. Dry, with small upright tufts of hair that flatten and can crack in dry weather. Deep blackish violet to purple, occasionally brightening toward royal purple or graying slightly as it ages (Siegel & Schwarz). |
| Gills | Notched where they meet the stem, moderately close together at first and more widely spaced with age. Start the same deep violet as the cap, turning grayish purple and then rusty brown once spores mature on them (Siegel & Schwarz). |
| Stem | 1–2.5 cm thick at the top and 6–18 cm long, often club-shaped with a swollen base up to 4 cm across. Dry and fibrous, deep violet with a paler violet sheen that darkens further where handled. A cobwebby cortina covers the young gills and leaves a fibrous band on the stem that collects rusty-brown spores as they mature (Siegel & Schwarz). |
| Flesh | Thick and fibrous, more brittle in the stem. Dark violet to violet-gray, grayer with age, staining a deeper purple when cut — most noticeable in a young stem (Siegel & Schwarz). |
| Spore print | Rusty to reddish brown. |
| Odor & taste | Faintly cedar-like; taste not distinctive (Siegel & Schwarz). |
| KOH | Turns deep blood-red on all parts — a useful chemical check if you carry a KOH test kit (Siegel & Schwarz). |
Deep violet all over, a rough velvety cap, rusty-brown spores
No other common Pacific Northwest mushroom combines this depth of violet-black color, a dry cap roughened by small upright tufts, and a cobwebby cortina that collects rusty-brown spores as it matures (Siegel & Schwarz).
Similar Species
- Violet Leptonia (now placed in Entoloma): Shares the color and rough cap texture but runs smaller, has no cortina, and drops pinkish-buff rather than rusty-brown spores (Siegel & Schwarz).
- Arora notes that among the many violet Cortinarius species in the region, none reaches this one’s near-black depth of color, and its dry, rough cap surface is a further distinguishing feature (Arora).
- Wood blewit (Collybia nuda): Also purple and found in similar duff, but the resemblance stops at color. A spore print settles it: blewits print pinkish-buff, this species rusty brown, and only this species shows a cobwebby cortina when young. See the wood blewit guide for the full comparison.
One Species, or Two?
European mycologists split violet Cortinarius into two subspecies — subsp. violaceus on hardwoods and subsp. hercynicus on spruce — distinguished by spore shape and host tree (Brandrud). Pacific Northwest material hasn’t been sorted the same way: genetic work cited in Mushrooms of Cascadia (Siegel & Schwarz) suggests our larger, conifer-associated mushrooms belong within a broad, variable C. violaceus rather than a distinct species, and MycoMatch says it isn’t entirely clear which population occurs here. Danny Miller’s PNW sites (D. Miller, PNW Pictorial Key; D. Miller, Danny’s DNA Discoveries) also treat the regional violet webcap simply as Cortinarius violaceus, with no separate PNW name in use.
Habitat & Season
This species grows alone, scattered, or in small clusters and pairs, rising from duff, moss, or well-rotted wood. It’s widespread and can be locally common, turning up most often at middle and higher elevations in the Cascades as well as along the coast; look for it from late summer into fall (Siegel & Schwarz). MycoMatch records it under conifers and, less often, in mixed or hardwood stands (Arora). iNaturalist observations from Oregon and Washington run from midsummer through early winter, with a sharp peak in October:
Based on 1,464 research-grade iNaturalist observations from Oregon and Washington
Edibility
We don’t recommend eating this, or any Cortinarius
Mushrooms of Cascadia (Siegel & Schwarz) rates the violet webcap itself as edible, describing the flavor as earthy with a slight bitter, metallic edge, and Arora calls it edible but not choice.
Its genus is the reason to leave it alone anyway. Cortinarius includes species that cause orellanine poisoning — kidney failure that can take one to two weeks to show symptoms, well documented in the deadly webcap, Cortinarius rubellus, which also grows in Pacific Northwest conifer forests (Siegel & Schwarz). Hundreds of Cortinarius species occur here, most poorly known and difficult to separate without a microscope. We treat every species in the genus, including this one, as not worth the risk of a misidentification — the same rule the wood blewit guide gives for any purple mushroom with rusty-brown spores or a cortina.
Sources: Mushrooms of Cascadia (Siegel & Schwarz, 2024); MycoMatch (© Ian Gibson), a compilation of published descriptions through which most other field-guide authors named here are quoted; Danny’s DNA Discoveries and the PNW Pictorial Key (© Danny Miller); iNaturalist observations.