Rickenella fibula

Description
Mushroom Identification
Look-Alikes
Synonyms

Description

Rickenella fibula or Omphalina fibula is a species of fungus belonging to the genus Rickenella. It is orange to yellow and occurs among moss. The cap is quite small, with a diameter usually less than 1 centimetre (3⁄8 in). The stipe is relatively long. It has little odor or taste, and is regarded as nonpoisonous but it has no culinary value. It can be found across North America.

According to molecular analysis, the species is more closely related to certain polypores and crust fungi than other gilled mushrooms.

This mushroom doesn't contain any hallucinogenic substance.

Common names: Orange Moss Agaric, Orange Nail Fungus, Orange Mosscap.

Mushroom Identification

Ecology

Probably saprobic but involved in some sort of mutualism with moss; growing alone, scattered, or gregariously in moss beds; spring through fall, or overwinter in warm climates; widely distributed in North America.
Cap

2–10 mm across; blocky or squarish at first, becoming convex, then broadly convex, with or without a shallow central depression; tacky when fresh but soon dry; bald or, with a hand lens, very finely hairy; the margin translucent-lined by maturity; orange with a whitish margin when fresh and young; soon fading to yellowish-orange overall, with a darker orange center.
Gills

Running deeply down the stem; distant or nearly so; short-gills in several tiers; creamy or very pale orange.
Stem

5–45 mm long; 0.5–1.5 mm thick; equal; dry; bald; colored like the cap; basal mycelium white.
Flesh

Insubstantial; pale.
Odor and Taste

Not distinctive
Chemical Reactions

KOH negative on cap surface.
Spore Print

White.
Microscopic Features

Spores 3–4 x 1.5–2.5 µm; ellipsoid; smooth; hyaline and 1- to 3-guttulate in KOH; inamyloid. Cheilocystidia and pleurocystidia 25–40 x 5–7.5 µm; fusiform with tapered or subcapitate apices; thin-walled; hyaline in KOH; smooth. Pileipellis a tightly packed cutis with numerous pileocystidia 50–100 x 7.5–12.5 µm, fusiform with wide bases and tapered, subcapitate, or capitate apices, thin-walled, smooth, hyaline in KOH.

Look-Alikes

The fact that the gills run deeply down the stem will separate Rickenella fibula from most marasmioid and mycenoid contenders — and the penchant for moss will help to separate it from Xeromphalina kauffmanii and Xeromphalina campanella, which grow in dense clusters (often numbering in the hundreds) on deadwood. Also compare Rickenella fibula with Cantharellus minor and Hygrocybe cantharellus, which are usually a bit larger than Rickenella fibula. Rickenella swartzii also very similar.