AbstractA new species,Nanobryum thorsbornei, is described from northern Queensland, Australia, and compared withN. dummeri, an African species to which it seems most closely allied. They both have a remarkable persistent protonema which is partly pseudothallose but the leaves of the Australian species are trilobate, a feature lacking in the African species. The relationship ofNanabryumwithFissidens, particularlyF. gladiolus, is discussed.