Panaeolina

Genus at a glance

Field	Detail
Classification	Genus (sometimes treated within Panaeolus)
Family	Bolbitiaceae
Described species	~10
Spore print	Dark brown to black, with roughened (ornamented) spores
Distribution	Cosmopolitan; common in lawns and grassland
Habitat	Grassy soil, lawns, occasionally dung
Key alkaloids	Trace psilocybin/psilocin reported in some species (debated)

Overview

Panaeolina is a small genus split from Panaeolus on a microscopic character: its spores are ornamented (roughened) rather than smooth. The best-known species, Panaeolina foenisecii — the "mower's mushroom" or "lawn mower's mushroom" — is one of the most common lawn fungi in the temperate world, which is exactly why it matters here. It has long been the subject of debate over whether it contains psilocybin.

Reports are inconsistent: some analyses have found trace psilocybin and psilocin, others none, and the compound serotonin and related indoles complicate the chemistry. Because it is so abundant in lawns where children and pets roam, P. foenisecii is a frequent subject of poison-control calls, usually with little or no effect.

Documented species

Species	Notes	Distribution
P. foenisecii	"Mower's mushroom"; trace/variable psilocybin reported, often none	Cosmopolitan
P. castaneifolia	Reported variable indole content	Temperate

Under-documented & emerging

Panaeolina is a small, under-studied genus whose flagship species has produced contradictory chemical results for decades — a reminder that "psychoactive" is not a binary label but a question of which population, season, and assay. Whether P. foenisecii should be considered a psilocybin mushroom at all remains genuinely unsettled, and the rest of the genus is barely characterised.

How to read this

Educational profile only. Panaeolina foenisecii is an extremely common lawn mushroom of contested and at most marginal activity; it is included here for completeness and because it is so frequently encountered and misidentified.