Gyroweisia brevicaulis (C. Müll.) Broth., Nat. Pflanzenfam. I(3): 389. 1902. Didymodon brevicaulis (C. Müll.) Fleisch., Musci Frond. Archip. Ind. Exsic. 6: n. 272. 1902, illeg. hom. Trichostomum brevicaule Hampe ex C. Müll., Syn. Musc. Frond. 1: 567. 1849.

Plants tiny, only to 1.5 mm high, in gregarious tufts. Stems simple, very short, rarely branched. Leaves contorted-curved when dry, erectopatent when moist, lanceo-ligulate, rounded-obtuse at the apex; margins entire, plane or somewhat wavy; costa ending below the apex; upper leaf cells rounded-hexagonal, thick-walled, more or less hyaline, mammillose; basal cells irregularly rectangular, larger than the upper cells, thin-walled, hyaline. Dioicous. Perichaetial leaves not much differentiated from stem leaves. Setae straight, ca. 6 mm long; capsules erect to slightly curved, ovoid-cylindrical; annuli weakly differentiated, of 1 row of cells; opercula conic-rostrate, with a short, thick beak; peristome teeth erect, densely papillose. Spores ca. 7 µm in diameter, smooth.

Type. Cuba: D. Poeppig s.n.

Chinese specimens examined: FUJIAN: Xia-ming City, D.-K. Li 10944 (HKAS, SHM). JIANGSU: Jiang-ning Co., M. Zang 15 (HKAS). XIZANG: Cha-yu Co., M.-Z. Wang 12759 (PE). YUNNAN: Kun-ming City, Koponen 37405 (H, HKAS); Lv-chun Co., M. Zang 49 (HKAS).

Habitat: on rocks or thin soil over rocks, sometimes on tree trunks; Distribution: China, Indonesia, Brazil, Honduras, Jamaica, Puerto Rico, Haiti, Cuba, and U.S.A.

Illustrations: C. Gao (ed.) 1996 (Pl. 51, figs. 5–10, as Gyroweisia brevicaulis).