Cortinarius mucosus

Description

Cortinarius mucosu is a medium to large agaric with a hat that is yellowish-brown and very slimy. It has cinnamon or rust-colored gills, a stout white stem with a ring zone, and a slightly swollen base. It grows on soil, usually in small groups or singly, in birch and conifer forests, nearly always on dryish acidic soil. This species is most often found in association with two-needle pines, with which it forms mycorrhizas.

This mushroom is generally regarded as 'suspect' and may contain dangerous toxins; it should not be gathered for eating. Some reddish Cortinarius species with which the Girdled Webcap could be confused contain the toxin orellanine, which if eaten destroys human kidneys and liver.

Common names: Slimy Cortinarius, Orange Webcap.

Mushroom Identification

1. Ecology

   Mycorrhizal with pines (especially, but not exclusively, with 2- and 3-needled pines) and with other conifers; growing alone, scattered, or gregariously; late summer and fall; apparently widely distributed in North America.

2. Cap

   4-12 cm; convex, becoming broadly convex or nearly flat; slimy when fresh; bald; brownish orange, fading to orangish or yellowish with age.

3. Gills

   Attached to the stem; close or nearly crowded; creamy at first, becoming cinnamon to rusty brown.

4. Stem

   4-10 cm long; up to about 2.5 cm thick; more or less equal; white; covered with a glutinous slime veil when fresh and young, but eventually more or less dry; often with rusty fibrils or a ring zone.

5. Flesh

   Whitish.

6. Odor and Taste

   Not distinctive.

7. Chemical Reactions

   KOH blackish-red on cap surface.

8. Spore Print

   Rusty brown.

9. Microscopic Features

   Spores 11-17 x 5-7.5 µ; amygdaliform; moderately to strongly verrucose. Pleuro- and cheilocystidia absent; marginal cells occasional. Pileipellis an ixocutis of clamped, ochraceous elements.

10. Similar Species

    Cortinarius collinitus is similar, but the stipe is girdled with white to orangish brown scales.

History

When French mycologist Jean Baptiste Francois (Pierre) Bulliard described this webcap in 1792 he gave it the binomial scientific name Agaricus mucosus. It was the Flemish botanist Jean Jacques Kickx (1842 - 1887) who, in 1867, transferred this species to the genus Cortinarius, thus establishing its currently accepted scientific name Cortinarius mucosus.

Synonyms of Cortinarius mucosus include Agaricus mucosus Bull., Agaricus collinitus ß mucosus (Bull.) Fr., and

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.

Just as you might expect, the specific epithet mucosus refers to the slimy coating that covers the cap and stem of this webcap mushroom.

Photo sources:

Photo 1 - Author: Jon W. Thompson (CC BY-SA 3.0)

Photo 2 - Author: Jon W. Thompson (CC BY-SA 3.0)

Photo 3 - Author: Chewy Chomp (chewy_chomp) (CC BY-SA 3.0)