Microstoma floccosum

What You Should Know

Microstoma floccosum is an inedible species in the cup fungus family Sarcoscyphaceae. It is recognizable by its deep funnel-shaped, scarlet-colored fruit bodies bearing white hairs on the exterior. Found in the United States and Asia, it grows on partially buried sticks and twigs of oak trees. The rim of the cup bears a distinct fringe of white hairs. It is leeches nutrients and energy out of decaying plant or animal matter.

This species prefers decaying hardwood sticks or logs on the forest floor to colonize. It produces its distinctive fruiting bodies in the summertime.

This mushroom is an ascomycete, meaning that its spores are produced inside specialized cells called asci. These are differentiated from basidiomycetes, which produce their spores outside specialized cells called basidia. Basidiomycetes constitute most “fleshy” fungi, including gilled mushrooms and pored mushrooms. Fungi such as yeasts, mildews, and molds are all ascomycetes. However, a few “fleshy” fungi are ascomycetes as well; these include morels, saddle fungi, and cup fungi.

The Latin name tells you a great deal about the mushroom: Microstoma means "small mouth," while floccosum refers to the "floccules" (small flocks, like a flocked Christmas tree) of white fuzzy hairs covering the fruiting bodies.

Other names: Shaggy Scarlet Cup, Pink Fringed Fairy Cup.

Microstoma floccosum Mushroom Identification

1. Ecology

   Saprobic on decaying hardwood sticks and logs (sometimes buried); growing scattered, gregariously, or (more often) in clusters of 3-6; early summer and summer; widely distributed east of the Rocky Mountains.

2. Fruiting Body

   Goblet shaped to cup-shaped, with a stem; to about 1 cm wide and 4 cm high; upper surface bald, bright red; outer surface red, covered with dense white hairs; margin fringed with white hairs that aggregate into pointed bundles; stem 1-3 cm high, 2-5 mm thick, whitish to grayish, densely hairy; flesh thin and reddish.

3. Microscopic Features

   Spores 20-35 x 14-17 µ; smooth; narrowly ellipsoid; when fresh sheathed with a thick hyaline perispore. Asci 8-spored; hyaline in KOH; inamyloid; cylindric. Paraphyses branched and networked, forming meshes and reticulate patterns; sometimes enclosing or encasing asci (and then sometimes creating the impression of asci with apical projections); septate; individual arms generally 1-3 µ wide; hyaline to, en masse, reddish in KOH. Hairs on excipular surface dissolving in KOH mounts to a central fragmented core of thin-walled, septate cells 4-5 µ wide - but in Melzer's reagent clearly visible as long, thick-walled elements up to 1,000 µ long and 20 µ wide.

Microstoma floccosum Look-Alikes

1. Microstoma apiculosporum

   The species from Taiwan has spores with short, sharply pointed tips.

2. Scutellinia scutellata

   Has a shallow red cup, no stalk, and black hairs on only the edge of the cap margin.

3. Sarcoscypha occidentalis

   Has a shape, size, and color that somewhat resemble M. floccosum, but it lacks any surface hairs, and the cup is not as deep.

4. Microstoma protractum

   Similar, but features a less hairy fruiting body and rubbery to gelatinous surfaces; it is found primarily in northern areas, while Microstoma floccosum is widely distributed east of the Rocky Mountains.

Sources:

Photo 1 - Author: Alan Cresswell (Creative Commons Attribution-Share Alike 3.0 Unported)

Photo 2 - Author: Dan Molter (shroomydan) (Creative Commons Attribution-Share Alike 3.0 Unported)

Photo 3 - Author: AJ (j7u) (Creative Commons Attribution-Share Alike 3.0 Unported)

Photo 4 - Author: Dan Molter (shroomydan) (Creative Commons Attribution-Share Alike 3.0 Unported)