37. Fissidens osmundoides Hedw., Sp. Musc. Frond. 1801.
Schistophyllum osmundoides (Hedw.) Lindb., Musc. Scand. 13. 1879.
Fissidens taelingensis C. Gao, Fl. Musc. Chinae Bor. Orient. 378. 1977. Type. China: Heilongjiang, Xiao Xing An Ling (Lesser Khingan Mt.), P.-C. Chen & C. Gao 387 (isotype SYS).
Plants small, yellowish green. Leafy stems usually simple, rarely branched, 3.8–6.0 mm long, 1.5–1.8 mm wide; axillary hyaline nodules not developed; central strand differentiated. Leaves in 7–10 pairs; lower leaves more or less loosely arranged, upper leaves densely arranged; middle to upper leaves oblong-ovate to ovate-lanceolate, 1.1–1.3 mm × 0.4–0.5 mm, often mucronate at apex; base of dorsal laminae rounded to wedge-shaped; vaginant laminae 1/2 –2/3 the leaf length, unequal; costa stout, ending 5–6(–9) cells below leaf apex; margins crenulate; cells of extreme apex quadrate to rounded hexagonal, smooth and thick-walled; cells of apical and dorsal laminae quadrate to rounded-hexagonal, 7.0–17.5 µm long, slightly mammillose, thin-walled, rather clear; cells of vaginant laminae hexagonal, smooth, with more clearly demarcated thick walls. Dioicous. Archegonia terminal, 350–430 µm long. Sporophytes not seen.
Type. Sweden: O. Swartz. s.n. (holotype G).
Fissidens osmundoides seems to be quite rare in China, and it is known only from Heilongjiang province in northeastern China. The description given above is based on a sterile isotype of Fissidens taelingensis.
Habitat: on logs; Distribution: China, Japan, Russia (Siberia), Europe, and North America.
Illustrations: Z.-H. Li 1985 (Fig. 19, i–p).