Hypnaceae

Diagnosis: Plants small, pale- to yellow-green. Stems creeping, irregularly branched. Stem and branch leaves similar, erect-spreading, symmetric, lanceolate, 0.3-0.6 mm long, gradually acuminate; margins entire to subserrulate; costa mostly absent; cells linear, straight to subflexuose, smooth, thin-walled, not porose, becoming shorter and short-rectangular in 1-2 rows across the insertion; alar cells few, in basal angles, quadrate to subquadrate. Setae elongate, smooth, orange, 0.5-1 cm long; capsules inclined, ± arcuate, asymmetric, short-cylindric with a fairly conspicuous neck, constricted slightly below the mouth when dry; exostome teeth shouldered, bordered, on the front surface cross-striolate below, coarsely papillose above. Spores finely papillose, 11-14 µm diameter.

Distribution: Central America; Caibbean; Western and Northern South America, Brazil

Ecology: Mostly growing on rotten wood, in humid forests.

Notes: In Isopterygium subbrevisetum the branches arise from leaf axils and therefore pseudoparaphyllia are lacking, in contrast to I. tenerum in which branches arise from pseudoparaphyllia-clad primordia

Basionym: Hypnum subbrevisetum Hampe

Basionym Citation: Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening i Kjøbenhavn ser. 3 6: 165. 1875.

Other Published Figures: W. R. Buck. 1998. Pleurocarpous mosses of the West Indies. Plate 125 (9-16).