21. Dicranum nipponense Besch. 东亚曲尾藓 dong-ya qu-wei xian
Ann. Sci. Nat., Bot. sér. 7, 17: 332. 1893. Type. Japan.
Dicranum rufescens Schimp. ex Paris, Index Bryol. (ed. 2) 2: 56. 1904, hom. illeg.
Plants medium-sized to moderately large, 2–5 cm high, deep green or yellowish green, somewhat shiny, in compact tufts. Stems erect, simple or branched, loosely foliate. Leaves appressed when dry, erect-spreading or falcate-secund at the tip of stems when moist, oblong-lanceolate, ca. 7 mm long, rather gradually narrowed from the upper 1/3, shortly acute to acuminate, somewhat keeled; margins plane, coarsely serrate in the upper 1/3, single-toothed; costa slender, subpercurrent, rarely shortly excurrent, usually ridged in 2–3(–4) rows at back nearly throughout; upper cells elongate, rhomboidal, 5–7 times as long as broad, incrassate; basal cells more elongate and broader, 120–150 µm × 16–22 µm, not particularly thick-walled, porose; alar cells rectangular, inflated, 45–80 µm × 35–40 µm, uni- or bistratose, pale yellowish brown. Dioicous. Perichaetial leaves high convolute-sheathing at base, abruptly narrowed to a short subula. Setae single, straight, 2–4 cm long, reddish brown; capsules cylindric, curved, inclined or horizontal, tapered at neck, urns ca. 3.6 mm × 1 mm, brownish; stomata present; opercula long-rostrate, 2.5–4.0 mm long; annuli none; peristome teeth 0.7 mm long, divided to the middle or lower, often perforated nearly to the base, papillose above, vertically striolate below, yellowish brown or reddish brown. Calyptrae cucullate, 5–6 mm long. Spores 16–22 µm in diameter, faintly papillose.