Astrothelium stromatofluorescens
Astrothelium stromatofluorescens is a bark-dwelling lichen in the Trypetheliaceae family. It was described as a new species in 2016 by lichenologists André Aptroot and Marcela Cáceres. The type specimen came from Parque Natural Municipal de Porto Velho in Rondônia, Brazil, where it grows on tree bark in a primary rainforest. The name stromatofluorescens refers to the yellow fluorescence of its pseudostromata under long-wavelength UV light.
The lichen has a smooth, pale ochraceous-green thallus with a thin black edge line. Its small fruiting bodies (ascomata) are 0.2–0.5 mm in diameter and appear in groups of 7–50 inside pseudostromata, which are layered structures mixing fungal and host tissue. Each ascus contains eight hyaline, spindle-shaped spores measuring 20–23 by 7–9 μm, with three transverse septa that create diamond-shaped chambers, and a gelatinous coating up to 6 μm thick.
The pseudostromata contain lichexanthone, the chemical that makes them fluoresce yellow under UV light. A similar species, Astrothelium phlyctaena, has lichexanthone in both the pseudostromata and the thallus.
Astrothelium stromatofluorescens is known from Brazil and Bolivia. Besides the type location in Rondônia, it has also been found in Amazonas (Brazil) and in the Ríos Blanco y Negro Wildlife Reserve in Santa Cruz, Bolivia.
This page was last edited on 3 February 2026, at 13:23 (CET).