1. Drummondia Hook. 木衣藓属 mu yi xian shu
Musci Amer., Brit. N. Amer. 62. 1828.
Plants medium-sized, slender and elongate, dark green to olive-green or black, often in compact mats. Stems creeping, densely branched, with branches erect, simple or dichotomously branched; rhizoids brown. Leaves rigid, crowded, appressed or somewhat curly when dry, erect-spreading when moist, elongate-ovate or oblong-lanceolate, acuminate or slightly obtuse at the apex; margins plane, entire; costae strong, ending near the apex; leaf cells rounded-polygonal nearly throughout, smooth, becoming larger near costae at the base. Autoicous or dioicous. Perichaetial leaves not or only slightly differentiated. Setae elongate; capsules ovoid, exothecial cells thin-walled or thick-walled; opercula conic, with an obliquely rostrate beak; annuli not differentiated; peristome single, short, not splitting, smooth. Calyptrae cucullate, smooth. Spores large, green, ovoid or ellipsoidal, multicellular, smooth or coarsely papillose.