Racomitrium subsecundum (Hook. & Grev. in Hook.) Mitt. & Wils., Kew J. Bot. 9: 324. 1857.
Trichostomum subsecundum Hook. & Grev. in Hook., Icon. Pl. 1: 17. 1836. Grimmia subsecunda (Hook. & Grev. in Hook.) Mitt., J. Proc. Linn. Soc., Bot. Suppl. 1: 45. 1859. Protologue: not indicated. Lectotype (Frisvoll 1988): H. 2716 (BM, NY).
Racomitrium cylindricum Schimp. ex Besch., Mém. Soc. Sci. Nat. Cherbourg 16: 184. 1872. Protologue: Mexico. In monte Orizabensi (Liebmann), in silva della Desierta Vieja (Bourgeau).
Racomitrium fragile Ren. & Card., Rev. Bryol. 36: 106. 1909. Protologue: Guatemala: Pico de Fuego (leg. R. Guérin; herb. F. Renauld).
Plants medium-sized to robust in loose tufts, olive‑green to yellow-green. Stems erect, fasciculate branched, 2–3(–5) cm high; rhizoids sparse. Leaves erect‑spreading to erect‑falcate when dry, spreading to falcate when wet, 2–3 mm long, lanceolate to ovate‑lanceolate, long-decurrent; apices long-acuminate, hair‑points long, short, or absent; margins uniseriate throughout or uniseriate below, irregularly bistratose above, recurved from 1/2–3/4 or plane; costa broad, percurrent or ending just below the leaf apex, dorsally flat in lower half, with 4–8 ventral surface cells; laminae unistratose, cells smooth or pseudopapillose; upper cells 14–35 μm, rectangular, thick‑walled, basal cells 25–80 μm long, elongate, long-rectangular, basal margins with 2–6 enlarged, hyaline, esinuose cells, alar cells reddish orange, enlarged, inflated, and bulging. Dioicous. Sporophytes not seen in Central America. Setae 6–14 mm long. Capsules 1.7–3.5 mm long, ovoid, oblong, or narrowly oblong-cylindric; peristome teeth linear, highly papillose, 530–610 μm, basal membrane absent. Spores 12–14 μm (Frisvoll 1988).
20. Racomitrium subsecundum (Hook. & Grev.) Mitt. 偏叶砂藓 pian-ye sha xian Hooker’s J. Bot. Kew Gard. Misc. 9: 324. 1897. Grimmia subsecunda (Hook. & Grev.) Mitt., J. Proc. Linn. Soc., Bot., Suppl. 1: 45. 1859. Trichostomum subsecundum Hook. & Grev. in Hook., Icon. Pl. 1: 17, f. 5. 1836. Type. Locality not indicated, H. 2716 (lectotype BM, by Frisvoll 1988, not seen). Racomitrium javanicum Dozy & Molk. in Zoll., Syst. Verz. 32. 1855. Racomitrium javanicum var. incanum Broth., Symb. Sin. 4: 466. 1929. Type. China: Sichuan, Ningyuen, Handel-Mazzetti 1446 (lectotype H, designated by Frisvoll 1988; isolectotype BM). Racomitrium javanicum var. molle Broth. ex Herz., Hedwigia 50: 127. 1910. Racomitrium javanicum var. muticum Broth. in Herz., Hedwigia 50: 127. 1910, nom. nud. Plants large to rather robust, up to 7–8 cm long, yellowish green or brownish green above, brownish or dark brown below, in loose tufts. Stems creeping or ascending, usually irregularly, sometimes subpinnately branched; central strand absent. Leaves imbricately appressed when dry, erect-spreading when moist, clearly secund, 2.6–4.0 mm long, ovate-lanceolate to oblong-lanceolate, keeled above, with hyaline hair-points, the hair-points often flexuous, variable in length, dentate or nearly smooth; margins recurved on one side up to 1/2–3/4 the leaf length, nearly plane or slightly recurved on the other side, unistratose in cross section; costa thick at base, slender upward, percurrent or nearly so; upper and median leaf cells rectangular, 10–23 µm × 3–6 µm, sinuosely thick-walled, smooth; basal cells narrowly rectangular or linear, 23–50 µm × 5–7 µm, sinuosely thick-walled, smooth; alar cells differentiated, usually reddish brown, auriculate, consisting of 2–4 rows of enlarged, thin-walled, rectangular or subquadrate cells. Perichaetial leaves similar to upper stem leaves, but without hyaline hair-points. Setae erect, reddish brown, 10–12 mm long, often twisted above; capsules erect, oblong-ovoid to cylindrical, reddish brown, 2.0–2.7 mm long; opercula long-rostrate; annuli well developed, consisting of 2–3 rows of thick-walled cells; peristome teeth linear, reddish brown, divided to the base, densely papillose. Calyptrae cucullate. Spores small, ca. 12 µm in diameter.
