The circumscription of Plagiomnium used here follows Koponen (1968) which restricts the genus to those species of Mnium sensu lato having plagiotropic stolons, macro‑ and micronemata, a Bryum‑type stem epidermis, and unistratose bordered, singly toothed leaves (rarely entire on the stolon leaves). Plagiomnium with 24 species in 5 sections (T. Koponen 1968, 1981) is found throughout the world; the greatest concentration of Plagiomnium species is in Asia. Koponen (1979) treated the genus for Central and South America.