Cortinarius alboviolaceus
Description
Cortinarius alboviolaceus is a basidiomycete mushroom of the genus Cortinarius native to Europe and North America. It is sometimes considered edible, but not recommended, but conflicting accounts indicate that it may be poisonous. It is a medium-sized species with a broadly umbonate silky fibrillose cap that is silvery bluish to bluish-white at first then develops yellowish tones and often becomes grayish white.
For a distinctive species, Cortinarius alboviolaceus can take some nerve to identify due to the wide variability within the species. It can vary in size, color, thickness of veil, viscidity, and even cap texture. In Europe, it occurs in hardwood forests, but in the PNW it is common in our conifer forests. It is often gregarious or scattered. It may be confused with Cortinarius camphoratus but that can be differentiated by the strong odor of rotting potato and different purple tones.
Some Cortinarius species contain the toxin orellanine, which if eaten destroys human kidneys and liver.
Common names: Silvery-violet Cortinarius, Pearly Webcap.
Mushroom Identification
Ecology
Mycorrhizal with hardwoods, especially birch; growing alone or gregariously; summer and fall; widely distributed in North America.
Cap
3-7 cm; convex to bell-shaped, becoming broadly bell-shaped or flat, with a broad central bump; dry; satiny; pale purplish at first, but covered with whitish veil material, becoming silvery or whitish lilac.
Gills
Attached to the stem; close; pale purplish at first, becoming cinnamon to rusty brown; covered by a white cortina when young.
Stem
5-9 cm long; up to about 1 cm thick at the apex; usually swollen at the base or club-shaped; dry; silky; pale lilac, especially near the apex; with whitish to silvery fibers that may trap mature spores and thus develop rusty colors; basally "booted" or sheathed with white veil material.
Flesh
Whitish or pale lilac.
Odor
Not distinctive, or very faintly radishlike.
Spore Print
Rusty brown.
Microscopic Features
Spores 7.5-9. 5 x 5-6 µ; ellipsoid; very slightly roughened (appearing almost smooth). Pleuro- and cheilocystidia absent. Pileipellis a cutis.
Similar Species
Cortinarius malachius has a slightly scaly cap. It is associated with conifers, as are Cortinarius camphoratus and Cortinarius traganus, which are noted for their penetrating smells; the former reminiscent of half-rotten potatoes, the latter sweet and sticky.
History
When in 1801 Christiaan Hendrik Persoon described this webcap he gave it the name Agaricus alboviolaceus. It was the great Swedish mycologist Elias Magnus Fries who, in 1838, transferred this species to the genus Cortinarius, whereupon it acquired its currently-accepted scientific name Cortinarius alboviolaceus.
Agaricus alboviolaceus Pers., is thus a synonym of Cortinarius alboviolaceus.
The generic name Cortinarius is a reference to the partial veil or cortina (meaning a curtain) that covers the gills when caps are immature. In the genus Cortinarius most species produce partial veils in the form of a fine web of radial fibers connecting the stem to the rim of the cap rather than a solid membrane.
The specific epithet alboviolaceus come from the prefix albo- meaning white and violaceus indicating that it is tinted or flushed with violet.
Photo sources:
Photo 1 - Author: Jerzy Opioła (CC BY-SA 4.0)
Photo 2 - Author: Jerzy Opioła (CC BY-SA 3.0)
Photo 3 - Author: Jerzy Opioła (CC BY-SA 4.0)
Photo 4 - Author: Ron Pastorino (Ronpast) (CC BY-SA 3.0)