15. Fissidens flabellulusThwait. & Mitt. 扇叶凤尾藓 shan-ye feng-wei xian
J. Linn. Soc. Bot. 13: 324. 1873. Type. Sri Lanka (Ins. Ceylon), Thwaites 142 (isotype? NY).
Plants small to very small. Leafy stems 0.7–1.4 mm long, 0.6.–1.2 mm wide, simple to rarely branched, densely foliated; central strand lacking; axillary hyaline nodules more or less differentiated. Leaves in 2‑7 pairs; upper leaves lanceolate to narrowly lanceolate, 0.7–1.2 mm × 0.1‑0.3 mm, acute to narrowly acute at apex, wedge-shaped at base of dorsal laminae; vaginant laminae about 1¤2 – 1¤3 the leaf length; costa stout, percurrent to shortly excurrent, often dividing laminae unequally, dorsal side often wider than ventral side at middle of leaves; margins of vaginant laminae more or less distinctly serrate by projecting laminal cells; cells of apical laminae quadrate to hexagonal, 10–17(–19) µm long, slightly mammillose to almost smooth, walls clear, moderately thick-walled; cells at upper part of vaginant laminae similar to those of apical laminae. Rhizoautoicous or autoicous; male inflorescence often terminal on stems; archegonia terminal on stems, 160–170 µm long. Setae 1.6–3.5 mm long; capsules ovoid to shortly cylindrical, erect and symmetrical; urns 0.3–0.5 mm long; exothecial cells quadrate, thin-walled with weakly thickened corners; opercula long conical to rostrate, 0.3–0.4 mm long. Calyptrae campanulate, ca 0.4 mm long, smooth. Spores 11–14 µm in diameter, almost smooth.