Pyrenulaceae

The Pyrenulaceae are a family of mostly lichen-forming fungi in the order Pyrenulales, though a few members are secondarily non-lichenized. They form thin crusts on bark and, less often, on rock, and partner with species from the green algal genus Trentepohlia. The family is characterized by flask-shaped fruiting bodies (perithecia) that typically open through a pore, and by ascospores whose internal walls form distinctive rounded to diamond-shaped chambers. The number of accepted genera varies among sources—recent phylogenetic treatments have sampled about 13, while broader taxonomic outlines list up to 16—and the Catalogue of Life includes around 395 described species as of 2026, with modelling estimates suggesting a true total of roughly 440 worldwide. Under current circumscription, the family is dominated by Pyrenula, which accounts for about two-thirds of the known species. The family was established by Gottlob Ludwig Rabenhorst in 1870, and its generic boundaries have been substantially revised since, most recently through molecular phylogenetic studies that have shown several traditionally recognized genera to be nested within Pyrenula.

Together with Graphidaceae and Trypetheliaceae, Pyrenulaceae form one of the three most species-rich tropical microlichen families. They are found mainly in humid tropical forests, where they typically grow on smooth, shaded bark in lowland to lower montane settings. Although a few species extend into temperate regions, diversity is overwhelmingly tropical. Recent revisionary work suggests that many apparently widespread species are actually complexes of narrower taxa, and that documented species richness is still rising quickly.