Hymenoscyphus fructigenus

Description

Hymenoscyphus fructigenus is a tiny cup fungus with caps maxing out at 4 mm. Growing in clusters on beechnuts, hickory shells, and acorns. It is often found fruiting alongside Mycena luteopallens a tiny gilled mushroom that seems enormous by comparison, since a single hickory shell can hold dozens of specimens of Hymenoscyphus fructigenus.

Common names: Acorn Cup Fungus.

Mushroom Identification

1. Fruiting Bodies

   1 - 2 (5) mm, disc-shaped, slightly depressed, on the stalk, with age with raised, wavy edge, white, whitish, creamy, pale yellowish. The hymenial layer is smooth, white, cream, or pale yellow, located on the inner surface.

2. Stem

   0.5 - 5 mm high, 0.1 - 0.3 mm in diameter, cylindrical, narrowed down, uneven, finely pubescent, whitish or yellowish, at the base with a reddish tinge.

3. Asci

   100-120 * 9-10 microns, club-shaped. Spores 20 * 5 microns.

4. Flesh

   The flesh is thin, light, and odorless.

Synonyms

1. Leptostroma virgultorum var. fructigenum (Bull.) Rehm

2. Peziza fructigena Bull., 1785

3. Peziza virgultorum var. fructicola Wallr., 1833

4. Helotium fructigenum (Bull.) P. Karst., 1871

5. Phialea fructigena (Bull.) Gillet, 1881

6. Helotium virgultorum var. fructigenum (Bull.) Rehm, 1893

7. Ciboria fructigena (Bull.) Killerm., 1935

Photo sources:

Photo 1 - Author: Fluff Berger (CC BY-SA 4.0)

Photo 2 - Author: bjoerns (CC BY-SA 4.0)

Photo 3 - Author: Eugene Popov (CC BY-SA 4.0)

Photo 4 - Author: Fluff Berger (CC BY-SA 4.0)