Barbula orizabensis C. Müll., Linnaea 38: 638. 1874
Protologue: Mexico. Mexico, ad muros humidos umbrosos urbis Orizaba: C. Mohr aug. 1857; in iisdem locis prius Liebmann et Freder. Müller.
Plants small to medium-sized, dull, yellow-green above, brown below, in tufts, 10–30 mm high. Stems red, erect, irregularly branched, sclerodermis and central strand present; rhizoids sparsely distributed at base of stems, smooth to roughened. Axillary hairs 6–7 cells long, all cells hyaline. Leaves 1.5–2.0 mm long, ligulate, ovate-lanceolate, or triangular-lanceolate, crowded to widely spaced on stems, erect-incurved and spirally twisted around the stem when dry, erect-spreading to spreading when wet, deeply grooved ventrally along the costa; apices obtuse to broadly acute, often emarginate, stoutly mucronate; lamina unistratose; margins entire, at times slightly denticulate at extreme apex, revolute to near the apex; costa short-excurrent, papillose at back on upper ventral and dorsal surfaces, surface ventral cells of costa quadrate to short-rectangular, guide cells and two stereid stereid bands well-developed, ventral and dorsal surface layers enlarged; upper cells quadrate or oblate, 4–8 μm, firm-walled, densely pluripapillose, basal cells rectangular to long-rectangular, firm-walled, pluripapillose, 14–28 x 6 μm, extreme basal cells enlarged, 16–40 x 8 μm, firm-walled, at times weakly porose, alar cells not differentiated. Dense clusters of obovate, clavate or globose, stalked, multicellular propagula often in leaf axils. Dioicous. Perichaetia and perigonia terminal; perichaetial leaves neither sheathing nor strongly differentiated. Setae 1 per perichaetia, smooth, 15–20 mm long, red. Capsules long-cylindrical, erect, 2–4 mm long, smooth; exothecial cells short- to long-rectangular, firm-walled; stomata in neck; opercula erect, long-rostrate, 0.7–1.0 mm long; annuli well-developed; peristome red-orange, basal membrane high, teeth spirally twisted, to 1.0 mm long, densely spiculose. Spores 6–10 μm, smooth or lightly papillose. Calyptrae not seen.