''Mycena crocea'', commonly known as the walnut mycena, is a species of mushroom in the family

Mycenaceae The Mycenaceae are a family of fungi in the order Agaricales. According to the ''Dictionary of the Fungi'' (10th edition, 2008), the family contains 10 genera and 705 species. This is one of several families that were separated from the Tricholom ...

. The small mushroom has a bright yellow, conical to broadly convex cap up to in diameter. The

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

is tough and thin, up to tall, bright yellow at the top becoming progressively orange towards the base. The gills are adnate, subdistant, and yellowish, becoming lighter in age; and the spore print is white. This mushroom is saprobic and found exclusively on hickory nuts and walnuts in eastern North America. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''crocea'' refers to the orange color. The mushroom is commonly known as the "walnut mycena" and was previously and commonly misidentified as ''Mycena luteopallens''.

Description

The cap is vivid yellow, conical to broadly convex cap and up to in diameter. When young the cap tends to be conical or bell-shaped becoming plane or flat at maturity. The margin is striated. The surface is moist, glabrous, and somewhat hygrophanous. The flesh is thin, pallid, and yellowish. Odor and taste are not distinctive. The gills have an adnate attachment and are a pale yellowish color. They are subdistantly spaced. The sturdy

is long by thick. The stipe is central, equal (i.e., roughly equal in thickness at the top and bottom), and dark orange to yellowish. The species is regarded as nonpoisonous, but is not necessarily edible.

Microscopic characteristics

The

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

s are 7–9 x 4–5 µm, smooth, and elliptical, and weakly amyloid to inamyloid. Pleurocystidia and cheilocystidia are present

Similar species

Mycena strobilinoides ''Mycena strobilinoides'', commonly known as the scarlet fairy helmet, is a species of agaric fungus in the family Mycenaceae. It is found in North America, where it fruits scattered or in dense groups on needle beds and moss. The mushroom is mo ...

'' is similar to ''M. crocea'', but is found in needle beds under conifers. '' Atheniella adonis'' has a fragile stem and a more reddish-pink coloration.

Habitat and distribution

''Mycena crocea'' are found exclusively on hickory nuts and walnuts in eastern North America. It was first described as ''Marasmius nucicola'' in 1925 but that name could not be used in ''Mycena''.

References

{{Taxonbar, from=Q5244920 crocea Fungi described in 1991 Fungi of North America Taxa named by Rudolf Arnold Maas Geesteranus