Cortinarius anthracinus

Description

Cortinarius anthracinus is a very rare inedible fungus, being a mycorrhizal symbiont (it forms mycorrhizae on the roots of trees). The cap is purplish-brown to dark. Grows from the plains to the mountains on sour, sandy, and moist soil, solitary or in small groups, in deciduous and mixed forests with a predilection for beeches, birches, or oaks, occasionally under pines between the muscles.

It is one of the easier species to identify with reasonable confidence from its macroscopic characters; however, to be quite certain you need to see young and mature specimens and assess spore size and ornamentation.

Cortinarius anthracinus is not toxic and could be ingested. But due to its small size and fragility, it is not suitable for consumption. Furthermore, the species being rare, it should be spared and left in place.

Common names: Uncommon Webcap.

Mushroom Identification

1. Cap

   The hygrophanous caps of Cortinarius anthracinus range from purplish-brown to almost black. Young caps are convex to conical, becoming flat with a distinct umbo and reaching 1 to 3cm in diameter when fully mature.

2. Gills

   Adnate or slightly decurrent, moderately spaced; at first pale purple, maturing cinnamon brown.

3. Stem

   The fibrous pale stem is pale purple and silkily fibrillose; in young fruitbodies, there is a slight violaceous flush towards the apex; cottony velar remains adhere to the stem most noticeably towards the base; 3-5mm in diameter and 3-5.5cm long.

4. Spores

   Broadly ellipsoidal or slightly amygdaloid; minutely to moderately verrucose (with a roughened surface), 8-10 x 5-6µm; dextrinoid.

5. Spore Print

   Rust-brown.

6. Odor

   Odor is not distinctive.

7. Habitat

   Mycorrhizal, in broadleaf and mixed woodland, often with birches.

8. Season

   August to November.

History

Swedish mycologist Elias Magnus Fries described this little webcap in his Epicrisis Systematis Mycologici of 1838 and gave it the scientific binomial name Cortinarius anthracinus by which it is generally referred to today.

The vast genus Cortinarius is subdivided by many authorities into subgenera, and Cortinarius anthracinus 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 anthracinus comes from the Greek anthrákinos meaning colored like ruby gemstone.

Synonyms

1. Cortinarius sanguineus var. anthracinus Fr., 1838

2. Dermocybe anthracina (Fr.) Ricken, 1915

3. Cortinarius purpureobadius P. Karst.

4. Cortinarius subanthracinus Rob. Henry

5. Dermocybe subanthracina (Rob. Henry) M.M. Moser.

Photo sources:

Photo 1 - Author: warren_cardimona (CC BY-NC 4.0)

Photo 2 - Author: marcofloriani (CC BY-NC 4.0)

Photo 3 - Author: fredojusto (CC BY-NC 4.0)

Photo 4 - Author: noah_siegel (Attribution-NonCommercial-ShareAlike 4.0 International)