8. Fissidens closteri subsp. kiusiuensis (Sak.) Z. Iwats., J. Jap. Bot. 33:249. 1958; Fissidens kiusiuensis Sak., Bot. Mag. Tokyo 47: 740. 1933.
Plants very small, light green to green, scattered on substrates; protonema not persistent. Leafy stems very short, 0.3–1.3 mm long, 0.2–1.2 mm wide; cortical stem cells more or less large, moderately thick-walled; central strand not differentiated. Leaves small, 1–4 pairs; upper leaves much larger than lower leaves, lanceolate to narrowly lanceolate, acute at apex, 0.3–0.9 mm × 0.1–0.2 mm; vaginant laminae 1/2 – 2/5 the leaf-length, usually open to costa at upper end; the base of dorsal laminae wedge-shaped, not distinctly decurrent; costa strong, usually ceasing several cells below the apex, in cross-section with distinct stereids; margins finely serrulate by projecting cells; cells of apical laminae irregularly quadrate, rectangular to rhomboidal, 13–17(–21) µm long, smooth, thin-walled, cells at upper portions of vaginant laminae rectangular, hyaline, thin-walled, often 50 µm long toward base.
Rhizoautoicous; male stems attached to the base of female stems; antheridia enclosed by perigonial leaves much shorter than perichaetial leaves; archegonia terminal on stems, ca 130 µm 1ong. Setae 1.3–4.0 mm long, smooth; capsules erect, symmetrical; urns ovoid, 0.2–0.5 mm long; opercula conic-rostrate, 0.2–0.4mm long; exothecial cells quadrate, thin-walled, but with distinctly thickened corners, smooth; peristome teeth 0.14–0.16 mm long, 20 µm wide at base, spirally thickened in upper 3/4, minutely papillose below. Calyptrae mitrate, about 0.3 mm long, covering only opercula, distinctly scabrous by a papilla at upper end of each surface cell. Spores 10–15 µm in diameter, smooth.
Type. Japan: Kyushu, Prov. Satsuma, K. Sakurai 1681 (holotype MAK).
Habitat: on soil; 2550 m alt; Distribution: China and Japan.
Chinese specimen examined: XIZANG (Tibet): Lin-zhi (Nyingchi or Pula) Co., Y. G. Su 2169 (HKAS, NICH).
Illustrations: Pl. 75, figs. 1–23.