Sarcosagium

Sarcosagium is a genus of crustose lichen-forming fungi in the family Thelocarpaceae. Established by the Italian lichenologist Abramo Bartolommeo Massalongo in 1856, it is currently regarded as a monotypic genus containing the single species Sarcosagium campestre. It is characterized by its inconspicuous, often gelatinous thallus and minute, reddish-brown, barrel-shaped apothecia. Its unusual morphology led to its placement in various groups historically, but genomic analyses have situated the genus within the Lichinomycetes, an ancient lineage of symbiotic ascomycetes. Its precise familial classification, however, remains a matter of ongoing discussion.

An ephemeral pioneer species, S. campestre typically colonizes transient or disturbed habitats such as acidic soils, decaying mosses, and urban wasteland across Europe and North America. It shows a high tolerance to heavy metals, frequently appearing on mine spoil heaps and tailings ponds enriched with zinc, lead, and copper. The species exhibits a distinct seasonal phenology, behaving as an autumn ephemerophyte (a species with short-lived fruiting bodies), with apothecia that emerge in late summer and disappear by winter. Because of its small size and preference for neglected anthropogenic sites, it is believed to be more widespread than current records suggest.