Bryostigma

Bryostigma is a genus of fungi of uncertain familial placement in the order Arthoniales. The genus is characterised by its thin, patchy growth that either partially embeds into its growing surface or forms an irregular, granular surface, with distinctive red or blue iodine staining of its hyphae and very small fruiting bodies. Most Bryostigma species are parasitic (lichenicolous), growing on other lichens, though a few species like B. lapidicola grow independently on stone or moss. While the genus was initially established with a single species growing on moss, it was significantly expanded in 2020 when several species were transferred from the related genus Arthonia based on DNA analysis, though this taxonomic reclassification has been subject to some scientific dispute. As of 2024, the genus includes seventeen species – thirteen parasitic and four independent lichen species.