Plants often slender or even filiform, sometimes brittle, often glossy, dark-green to yellow-green, and occasionally glaucous above, brown below. Stems freely branched by subfloral innovation; central strand usually none. Leaves usually broadly grooved along the costa and keeled, ligulate to lanceolate or linear-lanceolate, acute or rarely obtuse to rounded; margins plane or broadly recurved at 1 or both sides in the lower 2/3; costa usually covered ventrally by long-rectangular, smooth cells; upper cells usually irregularly subquadrate to short-rectangular at the margins, wider and short- to long-rectangular or rhombic inward, or sometimes subquadrate and ± homogeneous across the leaf with walls thin, evenly thickened, or ± thickened at corners (and sometimes porose with the middle lamella evident), the papillae usually present and usually low, simple to granulose, not obscuring the lumina, 1-3(-5) per cell, usually not crowded, centered over the lumina to apparently scattered. Dioicous. Perichaetia terminal, with inner bracts scarcely differentiated or broad and sheathing at base. Setae elongate; capsules subcylindric, systylious; operculum obliquely conic; peristome none.