Dawsoniidae

A subclass of the true mosses (Bryopsida) largely limited to the South Pacific. The subclass consists of a single genus, Dawsonia, of nine species. The plants are coarse and rigid in loose dark green or brownish tufts. They are simple or occasionally forked, grow erect from a procumbent base, and sometimes achieve a height of 26 in. (65 cm), much more than any other mosses. The stems may have a central strand of homogeneous fiberlike cells or both xylemlike and phloemlike cells. The leaves are long-linear or long-lanceolate from a relatively short, oblong-sheathing base. The limb, which may be as long as 1.6 in. (40 mm), is concave-tubulose and spreading or flat and spirally twisted when dry. It is coarsely toothed at the margins and at back. The inflorescences are dioecious and terminal. Male plants repeatedly form new growth through the perigonial bud. See also Bryophyta; Bryopsida; Polytrichidae.