36. Sphagnum riparium Ångstr., Öfvers. Förh. Kongl. Svenska Vetensk.-Akad. 21: 198. 1864.
Sphagnum intermedium var. riparium (Ångstr.) Braithw., Monthly Microscop. J. 13: 62. 1875. Sphagnum intermedium Hoffm. ssp. riparium (Ångstr.) Lindb., Musci Scand. 12. 1879.
Plants grayish or yellowish green, in loose tufts. Stem cortex in 2–3 layers, hyaline cells thin-walled, without fibrils and pores; central cylinder not much differentiated from cortical layers, pale yellowish green. Stem leaves 0.9–1.3 mm × 1.0–1.1 mm, triangular-ligulate or broadly ligulate, cucullate-concave, lacerate at the apex; borders rather wide on both sides, clearly widened near the base, ca. 1/3 the leaf width; hyaline cells rarely divided in the upper half, often divided in the lower half. Branches in fascicles of 4–5, with 2–3 spreading. Branch leaves 0.8–1.2 mm × 0.5–0.8 mm, ovate-lanceolate; margins strongly involute in the upper half, truncate, denticulate at the apex; hyaline cells fibrillose, with pores at the opposite ends of upper cells on the ventral surface, often with large, central pores on the dorsal surface; green cells in cross section triangular, exposed on the dorsal surface, enclosed by hyaline cells on the ventral surface. Dioicous; antheridial branches brownish. Perigonial leaves narrow at base, broader upward, abruptly pointed at the apex, borders wide. Perichaetial leaves large, elliptic, cells not dimorphous, sometimes with green cells only, hyaline cells without fibrils and pores. Sporophytes not seen.
Type. Sweden: Uppland.
Chinese specimens examined: HEILONGJIANG: Da Xing An Ling (Greater Khingan Mt.), C. Gao 12770 (IFSBH, KUN, MO), 12776, 12778, 12783, 12830 (IFSBH, KUN).
Habitat: usually in open bogs, or on wet ground under coniferous forests; Distribution: China, Japan, Russian Far East and Siberia, Europe, and North America.
Illustrations: C. Gao (ed.) 1994 (Pl. 18, figs. 1–3).