Hymenoscyphus fructigenus

What You Should Know

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.

Other names: Acorn Cup Fungus.

Hymenoscyphus fructigenus 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.

Hymenoscyphus fructigenus 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

Sources:

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

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

Photo 3 - Author: Eugene Popov (Creative Commons Attribution 4.0 International)

Photo 4 - Author: Fluff Berger (Creative Commons Attribution-Share Alike 4.0 International)