Fissidens Moss

The leaf shape of Fissidens pellucidus is variable. In the holotype the leaves are narrow with excurrent costa and the bases of dorsal laminae are wedge-shaped. However, in most Chinese specimens the leaves are broader mostly with percurrent costa (rarely excurrent) and the bases of the dorsal laminae always rounded. This species is closely allied to F. guangdongensis. The distinction between the two species is discussed under the latter.

Varieties 3 (1 in the flora): North America, Mexico, West Indies, Central America, South America, Asia, Africa.

Plants small, growing in loose tufts, usually brownish or reddish brown. Leafy stems simple, 2.4–5.2 mm long, 1.0–2.1 mm wide; axillary hyaline nodules lacking; central strand weakly differentiated. Leaves in 4–12 pairs, lower leaves very small, loosely arranged; upper leaves much larger than the lower leaves, densely arranged, lanceolate, 0.7–1.4 mm × 0.2–0.3 mm, acute to narrowly acute at apex; base of dorsal laminae wedge-shaped to rounded; vaginant laminae 1/2 the leaf length, unequal; costa stout, percurrent to shortly excurrent; margins crenulate to indistinctly serrulate; cells of apical and dorsal laminae quadrate to irregularly hexagonal, 10–24 µm long, thick-walled, transparent, smooth; cells of upper half of vaginant laminae similar to those of apical and dorsal laminae, but narrower toward the base. Polyoicous. Perichaetial leaves differentiated, upper end of vaginant laminae rounded, open to costa, cells at upper end of vaginant laminae elongate, irregularly rhombic, thick-walled. Archegonia 245–390 µm long. Setae 2.5–2.9 mm long, smooth; capsules erect, symmetrical; urns ovoid, 0.4–0.5 mm long; exothecial cells quadrate to broadly oblong, thin-walled with distinctly thickened corners, distinctly mammillose; opercula conic-rostrate, ca. 0.4 mm long; peristome teeth 0.28 mm long, 36 µm wide at base, spirally thickened above, densely covered by minute papillae below.

Distribution: China, Japan, Nepal, India, Sri Lanka, Myanmar, Thailand, Vietnam, Malaysia, Singapore, Indonesia, the Philippines, and South America.

Habitat: on soil.

Fissidens crassinervis Thwait. & Mitt., J. Linn. Soc. Bot. 13: 323. 1873, hom. illeg., non Fissidens crassinervis Sande-Lac., Verh. Kon. Ned. Akad. Wetensch., Afd. Natuurk. 13: 3. Pl. 2: a.1872. Fissidens laxus Sull. & Lesq., Proc. Amer. Acad. Arts Sci. 4: 275. 1859. Type. China: Hong Kong, C. Wright s.n. (holotype FH). Fissidens mittenii Par., Ind. Bryol. 477. 1894.