Brachydontium Moss

Description

Plants very small, 1-2 mm high, dull, yellowish brown. Stems erect or ascending, often simple. Leaves erect, in many rows, sometimes flattened and pseudodistichous, not altered when dry, linear-lanceolate, 1.0-1.5(-2) mm long; margins entire, sometimes irregularly serrulate at the shoulders; costa strong, filling most of the subula, excurrent; leaf cells obscure, subquadrate, thick-walled, smooth at shoulders, becoming short-rectangular below, rather laxly oblong-rhomboidal, pale at the insertion. Setae 2.0-2.5 mm long, erect, yellow, twisted above when dry; capsules cylindric, 0.4-0.5 mm long, yellow to pale brown, striate when dry; opercula rostrate, 0.3-0.4 mm long; annuli well developed, compound, 2-3 rows of large cells, deciduous when mature; peristome teeth very short, lanceolate or blunt to truncate, hyaline or pale yellow, faintly to densely papillose or sometimes smooth. Spores 8-12 -m, smooth, pale-yellow.Type. Germany: Weber s.n.Chinese specimen examined: SICHUAN: Mu-li Co., C. Gao s.n. (IFSBH).Habitat: on moist, acid rocks or on sandy soil; Distribution: China, Ukraine, Europe, and North America.The leaves of this species can be confused with those of Ditrichum and Seligeria, but the presence of very small plants, oblong-cylindric and striate capsules, straight rostrate opercula, very short, often papillose peristome teeth, and the presence of large, compound annuli are significant differences.Illustrations: C. Gao (ed.) 1994 (Pl. 45, figs. 11-16).