Clades:
Hypnodendrales,
Bryidae,
Bryanae,
Bryophyta,
Plants.
Genera: Powellia, Powelliopsis, Racopilum, Timokoponenia.
Genera: 2; ± species 70.
Region: nearly worldwide, primarily tropical and subtropical regions.
BotanyMoss: medium-sized; in creeping mats, dark green.
Stems: short-to-elongate, subpinnate or irregularly branched; branches spreading, short, densely tomentose proximally; axillary hairs of 5 cells, basal-cell short, brownish.
Leaves: usually dimorphic, in 4 rows; twisted-contorted when dry, spreading-erect when moist; lateral leaves in 2 rows, larger; dorsal leaves in 2 rows, usually much smaller; oblong-ovate, ovate-acuminate; margins toothed distally, unbordered; apex broadly acute, sometimes rounded; costa single; medial laminal cells quadrate to rhomboidal, smooth.
Sexual condition: dioicous or monoicous, autoicous or synoicous; perigonia gemmiform, leaves small, apex long-awned; perichaetial leaves differentiated.
Capsule: exserted, curved, sometimes straight; operculum beaked or rostrate; peristome double; exostome cross-striolate proximally, slender and papillose distally; endostome basal membrane high, papillose, cilia present or absent; seta single or rarely 2 per perichaetium, elongate, smooth; calyptra cucullate or rarely mitrate, hairs usually few-to-many, long, delicate.
Spores: smooth, seldom rough.