Collybia tuberosa

Collybia tuberosa
Collybia tuberosa with sclerotia
Scientific classification
Domain: Eukaryota
Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Clitocybaceae
Genus: Collybia
Species:
C. tuberosa
Binomial name
Collybia tuberosa
(Bull.) P.Kumm. (1871)
Synonyms

Agaricus tuberosus Bull. (1786)
Agaricus amanitae subsp. tuberosus (Bull.) Pers. (1800)
Gymnopus tuberosus Gray (1821)
Marasmius sclerotipes Bres. (1881)
Chamaeceras sclerotipes (Bres.) Kuntze (1898)
Collybia sclerotipes (Bres.) S.Ito (1950)
Microcollybia tuberosa (Bull.) Lennox (1979)

Collybia tuberosa
Gills on hymenium
Cap is convex or flat
Hymenium is adnate
Stipe is bare
Spore print is white
Ecology is saprotrophic
Edibility is inedible

Collybia tuberosa, commonly known as the lentil shanklet or the appleseed coincap, is a species of fungus in the family Tricholomataceae, and the type species of the genus Collybia.

The fungus produces small whitish fruit bodies with caps up to 1 cm (0.4 in) wide held by thin stems up to 5 cm (2.0 in) long. On the underside of the cap are closely spaced white gills that are broadly attached to the stem. At the base of the stem, embedded in the substrate is a small reddish-brown sclerotium that somewhat resembles an apple seed. The appearance of the sclerotium distinguishes it from the other two species of Collybia, which are otherwise very similar in overall appearance.

Like the two other members of its genus, C. tuberosa lives on the decomposing remains of other fleshy mushrooms. It is found in Europe, North America, and Japan, growing in dense clusters on species of Lactarius and Russula, boletes, hydnums, and polypores.

A 2023 chemical analysis found that this mushroom contains 49 mg/kg of the mycotoxin muscarine.