A revision of the North American lichen genus Ahtiana.

In English The formerly monotypic genus Ahtiana (type species: A. sphaerosporella (Müll. Arg.) Goward is shown to include two additional species, A. aurescens (Tuck.) Thell & Randl. and A. pallidula (Riddle) Goward & Thell. All three species are endemic to North America, and are characterized by their greenish yellow upper surface, globose ascospores, and caperatic acid in the medulla. The habitat ecology of these lichens is very specialized. Ahtiana is presumably most closely related to Tuckneraria Randl. & Thell and other cetrarioid genera having globose ascospores.