An order of the class Bryopsida in the subclass Bryidae. The order consists of a single genus and species, Bryoxiphium norvegicum, the sword moss. This order is characterized by a swordlike appearance owing to leaves overlapping in two rows. The shiny, rigid leaves are keeled and conduplicate-folded. The apex is long-awned at the stem tip and progressively shorter-pointed downward. The midrib bears at back a low ridge of one to four rows of cells. The leaf cells are smooth and subquadrate within, longer and narrower toward the margins. The plants are dioecious with terminal archegonia. The capsules are immersed and have an operculum but no peristome. The calyptra is cucullate, and the haploid chromosome number 14.