Fissidens intromarginatulus Bartr., Rev. Bryol. Lichénol. 23: 242. 1954.

Plants small, yellowish green, gregarious, with fertile and sterile stems mixed in the same patch. Leafy stems simple or branched, 2.3–5.0 mm long, 1.4–1.5 mm wide; axillary hyaline nodules not or only weakly differentiated; central strand not differentiated. Leaves in 7–20 pairs, the lowest leaves small, loosely arranged, the remainder much larger, more or less densely arranged, almost of constant size; middle to upper leaves oblong-lanceolate, 0.2–0.8 mm × 0.2–0.3 mm, acute to broadly acute at apex; base of dorsal laminae of fertile leaves usually wedge-shaped, rounded to wedge-shaped in sterile ones; vaginant laminae 3/5–2/3 the leaf length, equal to slightly unequal; costa light yellow, percurrent to slightly excurrent, with protruding rhombic cells; margins nearly entire; cells of apical and dorsal laminae quadrate to rounded-hexagonal, 7–8 µm long, obscure, pluripapillose, thin-walled; cells of vaginant laminae similar to, but larger than, those of apical and dorsal laminae, smooth and with thick walls toward the base near costa; limbidia usually found only on lower half of vaginant laminae of upper and perichaetial leaves, composed of 2–6 rows of cells, 1 cell thick, becoming shorter and the outermost layer changing into a row of quadrate to rectangular, papillose cells; limbidia of sterile stem leaves often weak or lacking. Autoicous. Male inflorescences terminal on main stems, rarely on short lateral branches. Archegonia 250–260 µm long. Perichaetial leaves differentiated, lanceolate; vaginant laminae with upper parts open to costa and with stronger limbidia. Setae 2.0–2.5 mm long, smooth, geniculate at base; capsules symmetrical, erect; urns cylindrical, 0.4–0.5 mm long; exothecial cells quadrate, thin-walled with distinctly thickened corners; peristome teeth ca. 0.2 mm long, 32 µm wide at the base; opercula rostrate, ca. 0.4 mm long. Calyptrae mitrate, ca. 0.3 mm long. Spores 11–12 µm in diameter.

Type. Sri Lanka (Ceylon): König s.n.

Chinese specimens examined: GUANGDONG: Guang-zhou City, P.-J. Lin 1224, 71692 (IBSC, SYS); Lofu Shan (Mt.), Magill et al. 8115 (MO); Shan-tou City, P.-J. Lin 3401 (IBSC, SYS). GUANGXI: Shang-si Co., 1974 Team 1903 (IBSC, SYS). HAINAN: Ba-wang-ling (Mt.), 1974 Team 3083 (IBSC, SYS); Diao-luo Shan (Mt.), 1974 Team 2765 (IBSC, SYS); Jian-feng-ling (Mt.), P.-C. Chen et al. 766c (IBSC, SYS); Ling-shui Co., Z.-H. Li 3561 (IBSC, SYS). TAIWAN: Nan-tou Co., Koponen 17586 (H); Ping-tung Co., Z.-Y. Wang 466 (NICH). YUNNAN: Cang-yuan, S.-M. Yu 80–1993 (H, HKAS); Jing-hong Co., Redfearn et al. 33736 (MO); Meng-la Co., Magill et al. 7663 (MO); Teng-chong Co., X.-J. Li 80–590 (H, HKAS); Xi-shuang-ban-na, X.-J. Li 3158 (HKAS, SYS), Redfearn et al. 33735 (MO).

Habitat: on soil, rarely on rocks; Distribution: China, Nepal, India, Sri Lanka, Thailand, Vietnam, Malaysia, Indonesia, the Philippines, and New Zealand.

Fissidens ceylonensis is closely related to F. hollianus. The distinctions between the two species are discussed under F. hollianus. In some Chinese specimens of Fissidens ceylonensis the limbidia on the vaginant laminae of fertile stems are very weak or sometimes lacking, causing confusion with other species.

Illustrations: Z.-H. Li 1985 (Fig. 12, i–u).