Leptodontium pungens (Mitt.) Kindb., Enum. Bryin. Exot. 63. 1888.
Didymodon pungens Mitt., J. Linn. Soc., Bot. 7: 150. 1864. Trichostomum pungens (Mitt.) Par., Ind. Bryol. 1329. 1898. Protologue: Cameroon. Cameroon Mtn, on rocks alt. 10,000 ft, Dec. 1862, Mann (NY).
Leptodontium acutifolium Mitt., J. Linn. Soc., Bot. 12: 51. 1869. Didymodon acutifolius (Mitt.) Jaeg., Ber. Thätigk. St. Gallischen Naturwiss. Ges. 1871-1872: 361. 1873. Protologue: Guatemala. Volcán de Fuego, Godman et Salvin. Ecuador. Andes Quitenses, Chimborazo et Cayambe, Jameson. Ecuador. Pangor et Carguairazo (procerius) ad rupes (10,000-11,000 ped), Spruce, n. 29. Lectotype (Zander 1972): Guatemala, Volcán de Fuego: Godman & Salvin, s.n. (NY).
Plants medium-sized in loose tufts, yellowish brown, 2–4 cm high. Stems red, erect or laxly ascending, hyalodermis present, sparsely radiculose. Leaves erect to erect-spreading, twisted to contorted when dry, spreading-recurved to squarrose-recurved when wet, lanceolate to ovate-lanceolate, 2.5–3 mm long, keeled above, erect-sheathing at base, not decurrent; apices acuminate; margins recurved in lower 1/2–2/3, dentate in upper 1/3; costa percurrent to subpercurrent, semicircular, with 2 ventral and 2–3 dorsal layers of stereid cells; upper leaf cells quadrate to subrectangular, or oblate, thick-walled with rounded corners, 5–10 x 3.7–10 μm, pluripapillose, papillae multifid, scattered, basal cells long-rectangular, thin- or firm-walled, 32–65 x 2.5–5 μm, often laterally thickened and porose pluripapillose, papillae simple, alar cells differentiated in small groups of yellow-red, short-rectangular, porose cells. Dioicous. Sporophytes not known in Central America, description based on South American plants. Setae straight, 10–13 mm long, yellow-brown. Capsules erect, cylindrical, 1.5–2 mm long, smooth to rugose when dry; exothecial cells short-rectangular; stomata at base of urn; opercula obliquely conic-rostrate, 0.7–1 mm long; peristome teeth linear, irregularly divided in upper 1/2–2/3, yellow-brown, smooth to indistinctly striate, preperistome sometimes present. Spores 12–17.5 μm, densely papillose. Calyptra not seen.