Fissidens serratus C. Müller 1847

Varieties 2 (1 in the flora): North America, Mexico, West Indies, Central America, South America, Asia, Africa, Pacific Islands.

Plants small, growing in loose tufts. Leafy stems simple, 0.5–1.7 mm long, 0.5–1.7 mm wide; axillary hyaline nodules indistinct; central strand not differentiated. Leaves in 2–5 pairs, densely arranged, upper leaves lanceolate, 0.5–0.7 mm × 0.1–0.2 mm, obtuse to acute at apex; base of dorsal laminae rounded to wedge-shaped, or ending a little above the base; vaginant laminae ca. 1/2 the leaf length, unequal; costa stout, light yellow, ending a few cells below leaf apex, often dividing leaf unequally; margins of apical laminae finely serrulate, those of vaginant laminae irregularly sharply serrulate; cells of apical laminae quadrate to hexagonal, slightly thick-walled, 8–11 µm long with a distinct central papilla; cells of upper part of vaginant laminae similar to those of apical laminae, becoming larger at middle part, smooth, rectangular, up to 18 µm long toward base. Rhizautoicous. Archegonia terminal, 140–200 µm long. Sporophytes not seen.

Distribution: China, Japan, Indonesia, the Philippines, Australia, Africa, Caribbean, and throughout the Americas.

Habitat: on tree trunks.

Fissidens papillosus Sande-Lac., Verh. Kon. Ned. Akad. Wetensch., Afd. Natuurk., Tweede Sect. 13: 1, pl. 1A. 1872.

Fissidens serratus is a species of moss belonging to the family Fissidentaceae.

A study in tropical Ecuador found that Fissidens serratus was typically not found in urban environments, suggesting that the species is sensitive to anthropogenic effects such as the presence of wastewater and heavy metal pollution. Contrarily, the closely related Fissidens elegans was frequently found in urban environments but not in more pristine nearby forests.