Common Stump Brittlestem

Conservation Status

IUCN Red List

not listed

NatureServe

NNR - Unranked

Minnesota

not listed

Description

Common Stump Brittlestem is a small, common, gilled mushroom. It occurs in Europe, Japan, and North America. In the United States it occurs east of the Great Plains and west of the Rocky Mountains. It is found from late summer through fall usually in dense tufts or large dense clusters. It usually appears at the base of hardwood stumps, and this is the source of its common name. It sometimes appears on logs or on woody debris. When appearing to grow on the ground it is attached to buried wood. It obtains its nutrients from dead wood (saprobic).

When it first appears, the cap is cone-shaped to hemispherical and dark reddish-brown. The upper surface is smooth, hairless, and moist. The tissue is dark and more or less transparent when moist, becoming paler and opaque as it dries out (hygrophanous). The margins are curved inward. A belt of white tissue, remnants of the partial veil, clings to the margins. As it ages, the color fades and the cap spreads out. Mature caps are broadly convex to nearly flat and usually ¾″ to 2″ (2 to 5 cm) in diameter, sometimes up to 2¾″ (7 cm) in diameter. They sometimes break as adjacent mushrooms expand. There is often persistent veil tissue hanging from the margins that discolors dark brown with maturing spores. As it dries out, the color fades to a pale honey-yellow to buff or tan, and the margin splits radial-wise along the gill margins, giving them a distinct starburst or flower-like appearance

The gills are brittle, closely spaced to crowded, and broadly attached to the stalk. They are whitish to pale brown at first, becoming brown as the spores mature. Between the main gills there are short gills that do not extend to the stalk.

The stalk is white, smooth, hollow, very fragile, 1¼″ to 4″ (3 to 10 cm) long, and ⅛″ to ⅜″ (4 to 9 mm) thick, the same thickness from top to bottom. It turns brown where bruised, and it often discolors brown near the base, darkened by falling spores. There is no ring, but there is occasionally an obscure zone of fibers where the partial veil was attached.

The flesh is thin, fragile, and brownish. It is edible when cooked but the taste is bitter. It should be avoided due to its similarity in appearance to many mushrooms whose edibility is not known, and to the deadly poisonous Funeral Bell (Galerina marginata).

The spore print is dark brown.

Similar Species

Psathyrella is a large genus of about 400 species. Many are small to medium-sized, have a convex to flat cap that is some shade of brown, and have a fragile white or pale stem. Common Stump Brittlestem is distinguished from similar Psathyrella species by its growth in clumps, usually at the base of hardwood stumps; the hygrophanous brown cap; the veil fragments on the margins of the cap that often persist and discolor dark brown with maturing spores; and the white fragile stalk.

Habitat and Hosts

Hardwoods

Ecology

Season

Late summer through fall

Distribution

Sources

24, 30, 77, 83.

Biodiversity occurrence data published by: Minnesota Biodiversity Atlas (accessed through the Minnesota Biodiversity Atlas Portal, bellatlas.umn.edu. Accessed 9/30/2026).

Psathyrella piluliformis (Bull.) P.D. Orton in Bánki, O., Roskov, Y., Döring, M., Ower, G., Hernández Robles, D. R., Plata Corredor, C. A., Stjernegaard Jeppesen, T., Örn, A., Pape, T., Hobern, D., Garnett, S., Little, H., DeWalt, R. E., Miller, J., Orrell, T., Aalbu, R., Abbott, J., Abreu, C., Acero P, A., et al. (2026). Catalogue of Life (2026-08-26 XR). Catalogue of Life Foundation, Amsterdam, Netherlands. https://doi.org/10.48580/dgyy9

Mycology Collections Portal (MyCoPortal) https://www.mycoportal.org/portal/collections/index.php). Accessed 9/30/2026.