Beyond hallucinations: the pharmacological and ecological significance of Panaeolus foenisecii

Panaeolus foenisecii (Pers.) R. Maire, commonly known as the brown hay or lawnmower’s mushroom, is a small saprotrophic species common in temperate regions of Europe and North America, colonizing nutrient-rich lawns, meadows, and parklands. Although it belongs to a genus that includes psychoactive mushrooms, recent studies classify it as non-hallucinogenic. Morphologically, it is characterized by a hygrophanous brown cap, mottled dark gills, and ellipsoid warty spores, making it a distinctive yet often overlooked member of urban and rural grassland ecosystems. As a litter-decomposing fungus, Panaeolus foenisecii contributes to nutrient recycling and soil fertility and may act as a bioindicator sensitive to soil pH, composition, and moisture. Chemical analyses have identified serotonin and 5-hydroxytryptophan among its metabolites, compounds associated with antioxidant and anti-inflammatory activity. Their concentrations vary with environmental factors such as temperature, rainfall, and soil mineral content, indicating ecophysiological plasticity. Toxicological data show only mild and transient gastrointestinal symptoms after accidental ingestion in humans or animals, suggesting minimal health risk. Despite lacking culinary or recreational use, the occurrence of bioactive indole derivatives underscores its potential ecological and pharmacological relevance. Panaeolus foenisecii illustrates the ecological and biochemical diversity within the Panaeolus genus and highlights the need for further investigation of non-hallucinogenic species. Its metabolic profile and environmental sensitivity make it a valuable model for studying fungal adaptation and the ecological significance of indole-based metabolites.