Grimmia milleri sp. nov. (Grimmiaceae) from northeastern North America and the status of Grimmia afroincurva

A new moss species, Grimmia milleri Hastings & Greven, is described from the mountainous parts of northeastern North America from the Adirondacks, New York to Maine. It has a unique combination of characters that in part otherwise defines two unrelated species of Grimmia, G. donniana and G. incurva. It is autoicous, with straight setae and smooth capsules like G. donniana, but the leaves are contorted and linear-lanceolate like G. incurva. Grimmia milleri is compared with G. afroincurva. The latter species is taken out of synonymy with G. incurva and G. fuscolutea and recognized here as a valid species.