Ferlums

Ferlums are a group of bioluminescent fungi in the order Agaricales. They are found in temperate forests in the Northern Hemisphere and are characterized by small to medium fruiting bodies that emit a greenish glow in darkness. The genus comprises several species with varying cap shapes and spore characteristics.

Fruit bodies typically have convex to flattened caps 2–6 cm across, color ranges from brown to ochre; gills are adnate to decurrent; the stem is slender, 3–8 cm tall. The most distinctive feature is bioluminescence, more intense on the edge of the cap and on the base of the stem, influenced by humidity and temperature. Spore prints are pale cream.

Ferlums grow on decaying hardwood and conifer logs, often in mixed stands. They are saprotrophic, contributing to wood decay, though some observations note associations with certain tree species. Their glow is hypothesized to deter nocturnal predators or attract insects that aid in spore dispersal, but the exact function remains under study.

They are identified primarily in Europe and North America, with reports in parts of Asia. Taxonomic placement places them in the class Agaricomycetes, with ongoing revision as molecular data accumulate.

Ferlums have attracted interest for their bioluminescence and potential bioindication properties. Research has focused on the biochemical pathways of light emission and the ecological role of glow. Edibility is not consistently assessed; several species are considered inedible due to texture or potential irritation.