Panaeolus papilionaceus

Description

Panaeolus papilionaceus is a "coprophilous" mushroom, which is a nice way of saying it grows on, um, dung (primarily that of horses and cows) or in soil that has been enriched with equine or bovine blessings. Aside from the habitat, identifying features include the black spore print; the gills, which are mottled gray and black; the tiny white partial veil fragments that hang like little teeth from the edge of the cap; the absence of a ring on the stem.

Until recently, this species was a part of a confusing group of mushrooms that included Panaeolus campanulatus, P. sphrinctrinus and P. retirugis. However, work by Gerhardt (1996) indicates the latter are conspecific, P. papilionaceous being the oldest valid name. Another dung inhabiting Panaeolus that may be encountered in our area is P. semiovatus a relatively large species that has a smooth, pale-colored cap and an annulus.

This mushroom is widely distributed in North America in Spring, Summer, and Fall and through the winter in warmer climates.

Common names: Agaricus Calosus, Panaeolus Campanulatus, Panaeolus Retirugis, Panaeolus Sphinctrinus, Petticoat Mottlegill.

Mushroom Identification

1. Pileus

   Cap 1.5-4.0 cm broad, obtusely conic, becoming bell-shaped; margin at first slightly incurved, then decurved, decorated with white veil fragments, the latter sometimes obscure in age; surface smooth, dry, subviscid in moist weather, olive-brown to gray-brown, occasionally yellowish-brown to reddish-brown at the disc; flesh grayish to buff-brown, thin; odor mild.

2. Lamellae

   Gills adnate to adnexed, sometimes seceding, close, broad, pale grey, the faces mottled darker from maturing spores, edges pallid; in age blackish overall.

3. Stipe

   Stipe 6-12 cm long, 2-4 mm thick, slender, fragile, hollow, more or less equal but sometimes slightly enlarged at the apex and base; surface striate above, otherwise pruinose (at least when young), gray-brown, darker where handled; partial veil fibrillose-membranous, white, evanescent, leaving fragments on the pileal margin.

4. Spores

   Spores 12-17 x 7-10 µm, elliptical, smooth, with an apical pore; spore print black.

5. Habitat

   Fruiting singly or in small groups on cow/horse manure and in pastures; fruiting spring and fall.

6. Edibility

   Not recommended; probably not toxic, but related species may be mildly hallucinogenic.

Photo sources:

Photo 1 - Author: Alan Rockefeller (CC BY-SA 4.0)

Photo 2 - Author: Copyright ©2011 Alan Rockefeller (CC BY-SA 3.0)

Photo 3 - Author: Diego Delso (1974–) (CC BY-SA 4.0)

Photo 4 - Author: Björn S... (CC BY-SA 2.0)