6. Racomitrium canescens (Hedw.) Brid. 砂藓 sha xian
Muscol. Recent. Suppl. 4: 78. 1819. Grimmia ericoides (Hedw.) Brid. var. canescens (Hedw.) Lindb., Musci Scand. 29. 1879. Grimmia canescens (Hedw.) C. Müll., Syn. Musc. Frond. 1: 807. 1849, hom. illeg. Trichostomum canescens Hedw., Sp. Musc. Frond. 111. 1801. Type. Europe.
Plants robust, up to 7–8 cm long, green or yellowish green above, brownish below, in dense or loose tufts. Stems ascending, sparsely and irregularly branched; central strand absent. Leaves imbricately appressed when dry, erect-spreading when moist, suddenly narrowed from a broadly ovate base to a shortly lanceolate apex, 2.2–2.4 mm × 0.8–1.0 mm, keeled above, with papillose, dentate, relatively long hyaline hair-points; margins recurved on both sides; costa relatively short, ca. 2/3–3/4 the leaf length, often forked at tips; upper and median leaf cells rounded-quadrate to short-rectangular, 7–11 µm × 7–9 µm, sinuosely thick-walled, coarsely papillose, unistratose at margins; basal cells rectangular to elongate-rectangular, 18–46 µm × 5–9 µm, densely papillose, strongly sinuosely thick-walled; alar cells distinctly differentiated, consisting of 10–15 inflated, quadrate to short-rectangular cells, 10–29 µm × 9–23 µm, thin-walled. Perichaetial leaves smaller than stem leaves. Setae dark brownish, erect, ca. 15 mm long; capsules oblong-ovoid to cylindrical, erect, reddish brown, ca. 1.5–2.0 mm long; peristome teeth linear, reddish brown, divided to the base, densely papillose. Spores not seen.