Brothera leana C. Müller 1900

This species often produces abundant clusters of brood bodies in axils of the upper leaves and appears to have grayish sheen, which is easily recognized in the fields.

Brothera leana is easily identified by clusters of brood leaves always present in the comal tufts. Campylopus fragilis has a similar appearance, but it has a different transverse section of the costa, with dorsal instead of median stereids. Furthermore, the ranges of the two species in North America do not overlap.

Plants small, 3–8 mm high, green or yellowish green with grayish sheen, in dense, compact tufts. Stems radiculose at the base, with many small, spindle-shaped brood bodies clustered in axils of the upper leaves. Leaves linear-lanceolate, 3.0–3.6 mm long, gradually narrowed from a short, tubulose base, subtubulose above; margins entire or slightly serrulate at the tips; costa broad, filling 1/3 – ½ or more of the leaf base width and nearly all of the subula; laminal cells thin-walled, rectangular above, marginal cells somewhat elongate, laxer at the base; alar cells not clearly differentiated. Setae ca. 8 mm long, reddish brown; capsules reddish brown, ca. 1.0 mm long, 0.5 mm in diameter, without stomata. Spores 10–15 µm in diameter, pale yellowish, mostly smooth.

Leaves 2-3 mm; margins entire; costa 155-180 µm wide; basal laminal cells 19-55 × 4-19 µm, narrower at margins; distal laminal cells 24-55 × 3-7 µm. Specialized asexual reproduction by clusters of spindle-shaped brood leaves in the comal tufts. Sporophytes not found in North America.

Distribution: China, India, Korea, Japan, Russia (Siberia), and North America.

Habitat: on tree bases or rotten wood, and rarely on rocks.

Leucophanes leanum Sullivant, Musc. Allegh., 41. 1846; Campylopus leanus (Sullivant) Sullivant & Lesquereux; Leucobryum leanum (Sullivant) Kindberg; Syrrhopodon leanus (Sullivant) Lesquereux & James

Brothera leana (SulL) C. Mull. Gen. Muse. 259. 1901
Leucophanes? Leanum Sull. Musci Allegh. 172. 1845. Campylopus Leanus Sull. in A. Gray, Man. ed. 2, 619. 1856. Leucobryum Leanum Kindb. Eur. & N. Am. Bryin. 176. 1897. Brothera Ankerkronae C. Mull. Gen. Muse. 258. 1901.
Dioicous: fertile plants densely tufted, rather light-green, glossy, with mostly unbranched, more or less radiculose stems scarcely 1 cm. high, uniformly foliate with erectspreading, lanceolate-subulate leaves, 3-3.5 mm. long on the upper part of the stem, with a subtubulose point entire except at the very apex, and often bearing in the axils of the upper leaves numerous, nearly linear, pale, deciduous, rudimentary leaflets 0.5 to nearly 1 mm. long; costa filling most of the upper part of the leaf, one third or more the width of the leaf belqw, in cross-section near the middle showing large outer cells on the under side of the costa similar to the outer cells of the upper side with some smaller more or less disconnected median cells mostly in one row, not forming a distinct stereid-band ; cells of the leaf-blade pale, thin-walled, rectangular, narrow at the margin, broader and often lax within, the alar group pale, fragile, often scarcely distinct from those of the blade; perichaetial leaves very similar to the upper stem-leaves: seta up to 7 mm. long, smooth, erect, somewhat sinuous and twisted: capsule oblong to elliptic, 1-1.3 mm. long, without stomata, smooth above, slightly rugose at the base, the exothecal cells narrow, elongate, with thick, somewhat flexuous walls ; annulus large, of two rows of cells; peris tometeeth inserted below the mouth, divided to near the base into two subulate, indistinctly articulate, densely papillose forks; lid with a long, erect beak: calyptra large, cucullate, ciliate at the base: spores nearly smooth, 10-12 fi in diameter. (Description of fruit mostly from a Japanese specimen.)
Type locality: Ohio.
Distribution: Pennsylvania; Ohio; Minnesota; Mexico; also in Japan, the Amur region of Siberia, and the Himalaya region.

Brothera leana là một loài Rêu trong họ Dicranaceae. Loài này được (Sull.) Müll. Hal. mô tả khoa học đầu tiên năm 1900.

白氏藓（学名：Brothera leana），又名白叶藓，为曲尾藓科白叶藓属下的一个种。