Orthotrichum tenue Hooker & Greville, Edinburgh J. Sci. 1: 120, plate 5 [lower left]. 1824

Leaves with basal laminal cells bulging, papillose-mammillose. Seta dextrorse, smooth. Capsule 1.3-2 mm; exothecial cells not or slightly differentiated; peristome consisting of low papillose membrane. Calyptra often splitting by one cleft along one rib.

Subspecies 2 (1 in the flora): se United States, Mexico, West Indies, Central America, South America, Asia, s Africa, Pacific Islands (New Zealand), Australia.

Subspecies tenuis is Old World in distribution.