3. Ditrichum difficile (Duby) Fleisch., Musci Fl. Buitenzorg. 1: 300. 1904; Trichostomum difficile Duby in Moritzi, Syst. Zoll. Pfl. Verz. 134. 1846.
Ditrichum flexifolium Hampe, Flora 50: 182. 1867.
Dicranum flexifolium Hook., Musc. Exot. 2: 144. 1819, hom. illeg.
Ditrichum formosicum Nog., J. Jap. Bot. 14: 397. 1938. Type. China: Taiwan, Taihei Shan (Mt.), Noguchi 6647 (holotype NICH).
Plants small to medium-sized, slender, 1.5–2.5 cm high, yellowish green, caespitose or in dense tufts. Stems erect, simple or sparsely branched, somewhat radiculose below. Leaves in several rows, flexuous or contorted above, linear-lanceolate, 4–6 mm long, rather abruptly narrowed from an oblong-ovate, sheathing base to a long, slender or setaceous acumen; margins plane, entire or sometime serrulate above; costa flat, percurrent or shortly excurrent, filling most of the subula; upper cells rectangular, 13–26 µm × 5–6 µm, moderately thick-walled; lower cells becoming elongate, 26–52 µm × 5–6 µm at the shoulder, 39–65 µm × 5–7 µm near the base, sometimes with several rows of linear and pellucid cells at the margins. Dioicous. Perichaetial leaves 7–8 mm long. Setae slender, straight, 3.0–3.5 cm long, reddish brown, twisted above; capsules cylindric or narrower below, suberect, ca. 2 mm long, asymmetric, reddish brown; peristome teeth linear, divided nearly to the base, yellowish brown, coarsely papillose. Calyptrae and spores not seen.
Type. Indonesia: Java, Zollinger 411.
Chinese specimens examined: TAIWAN: Taihei Shan (Mt.), see the type information of Ditrichum formosicum cited above.
Habitat: on soil; Distribution: China, Russia, India, Indonesia, Australia, New Zealand, South America, and South Africa.
Illustrations: C. Gao (ed.) 1994 (Pl. 34, figs. 1–7).