What You Should Know
Panaeolus fimicola (syn. Panaeolis Ater) is a widespread mostly inedible but not poisonous mushroom, which sometimes contains small amounts of the hallucinogen psilocybin.
It is hard to imagine a duller mushroom, but this very dark mottlegill somehow manages to make itself conspicuous on lawns after rain. The dark-brown caps sometimes almost black fade with age, covering a huge range of shades of brown.
Panaeolus fimicola Mushroom Identification
(1)1.5- 3.5(4) cm, Campanulate then convex to plane, obtuse, dingy gray to blackish, often with reddish or hazel tones, hygrophanous, pallid grey to yellowish when dry, smooth, with a narrow brown marginal band, slightly striate at the margin when moist. Flesh thin and grayish.
Adnate, close to crowded, at first gray-olivacous, becoming mottled and darkening to black with age, edges remaining whitish.
(4)6 - 8(10) cm x 1 - 2(3) mm, equal, slender, slightly enlarging at the base, hollow, fragile, dingy white to clay, becoming brownish towards the base in age, smooth, white-pruinose at the apex, obsoletely slightly silky-striate, ring absent. The flesh is dirty ochraceous-buff; fragile.
Spores Blackish gray. 10.8 - 14.2 X 6.9-9.5, ellipsoid or lemon-shaped, basidia 4 spored. Gill edge cystidia fusiform, typically with long necks, gill face cystidia absent.
In the spring or during the rainy seasons.
Habitat and Distribution
Panaeolus fimicola can be found growing in soil or dung, fertilized lawns and other grassy places, late spring to mid-fall. Widespread across the Americas, as well as Europe and Africa; common.
Growth habit - solitary to scattered.
Slight bruising at some of the specimens at the base.
Panaeolus fimicola Look-Alikes
The Dung Roundhead, has a transient ring and leaves a brown spore print.
The Brown Mottlegill, is a paler brown when wet and dries out from the cap center to become creamy-beige.
Panaeolus fimicola Taxonomy and Etymology
In 1788 a British mycologist, James Bolton, first described this species scientifically and gave it the (invalid) name Agaricus varius. It was the great Christiaan Hendrik Persoon who established its first valid species name (its basionym) in his milestone publication of 1801, naming it Agaricus fimicola.
Nearly three-quarters of a century later, in 1874, the currently accepted scientific name Panaeolus fimicola came about when French mycologist Claude-Casimir Gillet (1806 - 1896) transferred this species to the genus Panaeolus.
Synonyms of Panaeolus fimicola include Agaricus varius Bolton, Agaricus fimicola Pers., Prunulus varius (Bolton) Gray, Panaeolus fimicola var. ater J. E. Lange, Panaeolus obliquoporus Bon, and Panaeolus ater (J. E. Lange) Kühner & Romagn. ex Bon.
There is no consensus about the correct taxonomic position of fungi in the genera Panaeolus and Panaeolina, which some authorities include in the family Strophariaceae and others in the Bolbitiaceae.
Panaeolus, the genus name of this mushroom, means variegated and is a reference to the mottled or variegated coloring of the gills. The specific epithet fimicola comes from the Latin noun fimum, meaning dung, and the Latin verb colo, to inhabit - hence it means living on dung. These little brown mushrooms do often inhabit dung-enriched grassland, but they can also appear on lawns that have not been dolloped with dung.
Photo 1 - Author: Jerzy Opioła (Creative Commons Attribution-Share Alike 3.0 Unported)
Photo 2 - Author: Don Johnson (Creative Commons Attribution-Share Alike 3.0 Unported)
Photo 3 - Author: Jerzy Opioła (Creative Commons Attribution-Share Alike 3.0 Unported)
Photo 4 - Author: Jerzy Opioła (Creative Commons Attribution-Share Alike 3.0 Unported)