Streptopogon cavifolius Mitt., J. Linn. Soc., Bot. 12: 180. 1869.
Protologue: Ecuador. Andes Quitenses, Baños ad pedem montis Tunguragua, in ramulis praecipue malvacearum suffruticosarum, etiam in monte Guayrapata (6000–10,000 ped.), Spruce n. 140 (G, NY).
Plants small, scattered or gregarious, brownish to reddish green, corticolous. Stems 5–10 mm high, irregularly branched, central strand absent, cortical cells thin-walled, hyaline, uniform throughout; rhizoids densely clustered at base of stem. Leaves 2–2.5 mm long, oblong to narrowly spathulate, sheathing at base, concave, evenly spaced, appressed, contorted when dry, erect-spreading when wet; apices obtusely rounded, cucullate; margins entire, incurved above; costa narrow, subpercurrent to percurrent, ventral surface cells rectangular, smooth on both surfaces, guide cells and single (dorsal) stereid band well-developed, enlarged ventral epidermal cells absent, guide cells ventrally exposed; upper cells hexagonal to rhomboidal, 24–48 x 10–20 μm, thin-walled, somewhat bulging, smooth on both sides, longer near the costa, shorter near the margin, basal cells rectangular, thin-walled, smooth, 34–80 x 8–20 μm, those near the margin shorter and firmer walled, alar cells not differentiated. Asexually reproducing by clavate or cylindrical, multicellular, smooth gemmae borne singly on apical leaf surface. Dioicous. Sporophytes rare, not known from Central America, description based on South American plants. Setae 2 mm long, yellow. Capsules cylindrical, erect, 3.3 mm long, smooth, yellowish brown; opercula rostrate; peristome teeth filamentous. Spores not seen. Calyptrae mitrate.