15. Racomitrium joseph-hookeri Frisvoll 霍氏砂藓 huo-shi sha xian
Gunneria 59: 197. 1988. Type. Sikkim: J. D. Hooker 322.
Plants medium-sized, up to 3.5–4.0 cm long, yellowish green above, dark brown or blackish below, in loose tufts. Stems creeping or ascending, irregularly or subpinnately branched; central strand absent. Leaves imbricately appressed when dry, erect-spreading when moist, narrowly ovate-lanceolate to lanceolate, keeled above, 2.4–2.9 mm long, hyaline hair-points smooth, not dentate, somewhat flexuous, short to long; margins recurved on both sides, up to 1/2 the leaf length on one side, shortly recurved on the other side; costa thick at base, percurrent; upper leaf cells bistratose at margins, rectangular to elongate-rectangular, 11–35 µm × 5–9 µm, sinuosely thick-walled, with pseudopappillae (bulging cell walls), obscure; median cells similar to the upper cells; basal cells rectangular to elongate-rectangular, 30–50 µm × 8–9 µm, sinuosely thick-walled, bulging; alar cells not differentiated, consisting of only a row of 4–7, rounded rectangular cells, with straight and somewhat thick walls. Sporophytes not seen.