Fissidens involutus Wilson ex Mitten 1859

This species is characterized by its leaves with a paler region composed of smooth and thick-walled cells at the apex and the differentiation of a row of rectangular, smooth, hyaline cells along both sides of the costa.

Plants medium-sized to large, yellowish to brownish. Leafy stems rigid, simple or branched, 10–50 mm long, 2.0–5.0 mm wide; axillary hyaline nodules not or only weakly differentiated; central strand slightly differentiated. Leaves in 16–25 pairs, with inrolled apices even when moist; lower leaves often decayed; middle to upper leaves lanceolate, 1.3–4.0 mm × 0.3–1.0 mm, acute at apex; base of dorsal laminae rounded; vaginant laminae more or less unequal, 1/2 –3/5 the leaf length; costa stout, brownish red, percurrent, a row of cells on both sides of the costa rectangular, smooth and pellucid; margins finely serrulate or crenulate; cells at apex smooth, thick-walled, forming a paler region; cells of apical and dorsal laminae quadrate to rounded-hexagonal, 3.5–7.0 µm long, thin-walled, markedly mammillose and obscure; cells of vaginant laminae similar to those of apical and dorsal laminae, but much larger, smooth, with thicker walls toward the base near costa. Dioicous. Archegonia terminal on main stems, 568–610 µm long. Perichaetial leaves indistinctly differentiated, slightly narrower and shorter than stem leaves. Sporophytes not seen.

Distribution: China, Japan, Nepal, India, Myanmar, Thailand, Vietnam, and the Philippines.

Habitat: mostly on moist rocks, rarely on sandy soil.

Fissidens involutus Wils. in Hooker’s J. Bot. Kew Gard. Misc. 9: 294. 1857, nom. nud. Fissidens irrigatus Broth., Sitzungsber. Kaiserl. Akad. Wiss. Math.-Naturwiss. Cl. 133: 559. 1924. Type. China: Sichuan (Setschwan), Handel-Mazzetti 1895 (holotype H-BR). Fissidens plagiochiloides Besch., J. Bot. (Morat). 12: 293. 1898. Type. China: Yunnan, Tsang chen, Delavay 1872 (holotype PC; isotypes FI, H-BR). Fissidens subinteger Broth., Symb. Sin. 4: 10. 1929. Type. China: Hunan, Handel-Mazzetti 12216 (holotype H-BR).

Fissidens involutus là một loài Rêu trong họ Fissidentaceae. Loài này được Wilson ex Mitt. mô tả khoa học đầu tiên năm 1859.