Cortinarius torvus

What You Should Know

In the difficult Cortinarius group of fungi Cortinarius torvus is one of the easier species to identify with reasonable confidence from its macroscopic characters - in particular, the whitish stocking-like structure left by the universal veil clinging to the lower part of the swollen stem; however, to be quite certain you need to see young and mature specimens and to assess spore size, ornamentation and other microscopic characters.

Cortinarius torvus – a northern, beech-maple associate that appears in the fall, and a more southerly, oak-associated species with a more unpleasant odor, appearing in spring and summer.

Other names: Stocking Webcap.

Cortinarius torvus Mushroom Identification

1. Ecology

   Mycorrhizal with hardwoods, including beech and both red and white oaks; growing scattered to gregariously; spring, summer, and fall; probably widely distributed in eastern North America.

2. Cap

   3-8 cm; convex or irregular at first, becoming broadly convex, broadly bell-shaped, or nearly flat; dry; very finely silky or, in age, nearly bald; quite variable in color but generally lilac brown when young, fading markedly as it dries out to grayish lilac (often reminiscent of Lactarius argillaceifolius) or silvery-and eventually to a wishy-washy tan; the margin inrolled well into maturity.

3. Gills

   Attached to the stem; nearly distant; brownish purple when young, becoming rusty brown; covered by a whitish cortina when young.

4. Stem

   4-10 cm long; up to 1.5 cm thick at the apex; tapering to a club-shaped, swollen base; dry; pale purple above when fresh and young but later silvery to whitish or faintly brownish; sheathed or "booted" from the base with whitish to lilac gray veil material that often terminates in a folded-over, fragile ring.

5. Flesh

   Whitish, or with purple to gray shades in the stem.

6. Odor

   Strong and sickly sweet.

7. Chemical Reactions

   KOH negative to gray on cap; grayish to gray on flesh.

8. Spore Print

   Rusty brown.

9. Microscopic Features

   Spores 8-11.5 x 4.5-6 µ; ellipsoid, with a narrowed apicular end; weakly to moderately verrucose. Cheilo- and pleurocystidia absent, but subclavate, septate marginal cells present on gill edges. Pileipellis a cutis of hyaline to brownish, occasionally encrusted elements.

Cortinarius torvus Taxonomy and Etymology

Swedish mycologist Elias Magnus Fries described this webcap mushroom in Systema Mycologicum in 1921, giving it the scientific name Agaricus torvus. Later, in his Epicrisis Systematis Mycologici of 1838, Fries transferred the Stocking Webcap to the genus Cortinarius, establishing its currently accepted scientific name gave it the scientific binomial name Cortinarius torvus.

Synonyms of Cortinarius torvus include Agaricus torvus Fr.

The vast genus Cortinarius is subdivided by many authorities into subgenera, and Cortinarius torvus belongs to the subgenus Telemonia.

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.

The specific epithet torvus is a Latin word meaning 'staring, keen, piercing, wild, stern, fierce, grim or savage (esp. in look or expression)', which may not be too far from this webcap's grim colors or its stern look.

Sources:

Photo 1 - Author: Strobilomyces (Creative Commons Attribution-Share Alike 4.0 International)

Photo 2 - Author: Strobilomyces (Creative Commons Attribution-Share Alike 4.0 International)

Photo 3 - Author: Strobilomyces (Creative Commons Attribution-Share Alike 4.0 International)

Photo 4 - Author: Jerzy Opioła (Creative Commons Attribution-Share Alike 4.0 International)

Photo 5 - Author: Jerzy Opioła (Creative Commons Attribution-Share Alike 4.0 International)