Arrhenia epichysium

Description

Arrhenia epichysium is a species of agaric fungus in the family Hygrophoraceae. The fruit body has small brown to dark gray caps. The cap color changes from light gray to tan when it is dry. Gills are narrow and thin, placed together closely, and decurrently attached to the stipe. The spores are smooth and ellipsoid, measuring 6–7.5 μm. It is found in Asia, Europe, and North America.

Additionally, as suggested by the genus name, it is a lichenized fungus, i.e. forms a symbiotic relationship with an alga. Evidence of this association can sometimes be seen as clumps of algae at the base of the stipe.

Clitocybe epichysium and Omphalina epichysium are synonyms

Mushroom Identification

1. Ecology

   Possibly saprobic but involved in some sort of mutualism with moss; growing alone, gregariously, or in clusters on the deadwood of hardwoods and conifers; spring through fall; widely distributed in North America.

2. Cap

   1.5-5 cm across; planoconvex at first, becoming centrally depressed or vase-shaped; fairly smooth; the margin inrolled at first and later lined, often nearly to the center; blackish to dark grayish brown, fading markedly as it dries out and eventually pale grayish brown.

3. Gills

   Running down the stem; close or nearly distant; pale gray.

4. Stem

   Up to 3 cm long and 3 mm thick; more or less equal; dry; smooth or minutely hairy; colored like the cap but not fading as quickly.

5. Flesh

   Insubstantial; watery grayish.

6. Odor and Taste

   Not distinctive.

7. Spore Print

   White.

8. Microscopic Features

   Spores 7-9 x 4-5 µ; smooth; elliptical; inamyloid. Cystidia absent. Clamp connections are present.

Photo sources:

Photo 1 - Author: Holger Krisp (CC BY 3.0)

Photo 2 - Author: Holger Krisp (CC BY 3.0)

Photo 3 - Author: Garrett Taylor (Public Domain)