16. Sphagnum jensenii H. Lindb., Acta Soc. Fauna Fl. Fenn. 18(3): 13. 1899.
Plants rather stout, 10–15 cm high, whitish green, capitula often brown, in compact tufts. Stem cortex in 1–2 layers, hyaline cells relatively thick-walled, poorly differentiated from inner cortical layers (4–5 layers) and central cylinder; central cylinder yellowish. Stem leaves 0.8–1.0 mm long, triangular to triangular-ligulate, nearly as long as wide, rounded truncate, dentate at the apex; borders narrow above, slightly widened below; hyaline cells linear-rhomboidal, rarely divided, without fibrils and pores, or rarely with fibrils and pseudopores on both surfaces in the upper cells. Branches in fascicles of 4, with 2 spreading, ca. 1.5–2.0 cm long. Branch leaves 2.2–2.4 mm × 0.5–0.9 mm, imbricate, sometimes secund, narrowly ovate-lanceolate, twice as long as stem leaves, gradually narrowed to a blunt and dentate apex; margins bordered by 2–3 rows of linear cells, entire, involute; hyaline cells linear-rhomboidal, densely fibrillose, with medium-sized, ringed pores on the ventral surface, with small, rounded, unringed pores in commissural rows on the dorsal surface; green cells in cross section triangular, exposed on the dorsal surface, enclosed by convex hyaline cells on the ventral surface. Dioicous; antheridial branches brownish. Perichaetial leaves ovate, broadly bordered. Spores pale yellowish, smooth, ca. 30 µm in diameter.
Type. Russia (formerly Finland).
Chinese specimens examined: HEILONGJIANG: Hong Xing, H.-F. Xie 5, 18 (KUN); Shuangzihe, C. Gao 146 (IFSBH, KUN); Wu Ying, Y.-C. Zhu 6317 (KUN, MO); Xiao Xing An Ling (Lesser Khingan Mt.), P.-C. Chen & C. Gao 149 (IFSBH, MO); Yichun City, S.-E. Liu 7940 (IFSBH, MO). JILIN: An-tu Co., T. Koponen 36946 (IFSBH, MO); Changbai Shan (Mt.), C. Gao 7337 (IFSBH, KUN), S.-E. Liu 1772 (KUN). LIAONING: Changbai Shan (Mt.), K.-C. Lang 1, 47 (KUN, PE). NEI MONGOL: Wufeng Shan (Mt.), C. Gao 800 (IFSBH, KUN). SICHUAN: Xiao-jing Co., J.-S. Zhao 363 (KUN). YUNNAN: Gong-shan Co., M. Zang 572 (KUN, MO).
Habitat: in peatland under coniferous forests or on wet rocks near streams; Disribution. China, Japan, Central Asia, Russian Far East, Europe, and North America.
This species is characterized by having slender, brownish plants with small stem leaves and elongate branch leaves (twice as long as stem leaves), and by having linear-rhomboidal hyaline cells of branch leaves with commissural pores on both surfaces.
Illustrations: C. Gao (ed.) 1994 (Pl. 6, figs. 1–9).