Biatora alnetorum (Ramalinaceae, Lecanorales), a new lichen species from western North America

Biatora alnetorum S. Ekman & Tønsberg, a lichenised ascomycete in the family Ramalinaceae (Lecanorales, Lecanoromycetes), is described as new to science. It is distinct from other species of Biatora in the combination of mainly three-septate ascospores, a crustose thallus forming distinctly delimited soralia that develop by disintegration of convex pustules and the production of atranorin in the thallus and apothecia. The species is known from the Pacific Northwest of North America, where it inhabits the smooth bark of Alnus alnobetula subsp. sinuata and A. rubra. Biatora alnetorum is also a new host for the lichenicolous ascomycete Sclerococcum toensbergii Diederich.