45. Sphagnum warnstorfii Russ., Sitzungsber. Naturf.-Ges. Dorpat. 8: 315. 1888.
Sphagnum warnstorfianum Du Rietz in Sjörs, Svensk. Bot. Tidskr. 38: 405. 1944 , nom. superfl.
Plants slender, often erect, sometimes soft, bright to dull green or yellowish green, tinged with pink or reddish brown spots, in compact tufts. Stem cortex in 2–4(–5) layers, hyaline cells thin-walled, without fibrils or pores, sometimes with a single pore; central cylinder reddish purple, rarely green or colorless, distinctly differentiated from cortical layers. Stem leaves 0.7–1.3 mm × 0.5–0.8 mm, ligulate or triangular-ligulate, gradually narrowed to a rounded, dentate apex; borders narrow above, suddenly widened in the lower half, ca. 1/3 – 2/5 the leaf width at base; hyaline cells rhomboidal, mostly divided, without fibrils and pores, or with the traces of fibrils in the upper cells. Branches in fascicles of 3–5, with 2–3 spreading. Branch leaves 0.9–1.2 mm × 0.4–0.5 mm, clearly in 5 rows, ovate-lanceolate, gradually acuminate; margins involute; hyaline cells fibrillose, with large, rounded pores along commissural rows on the ventral surface, with small, rounded, ringed pores in the upper half on the dorsal surface; green cells in cross section triangular to trapezoidal, exposed more broadly on the dorsal surface, slightly exposed or enclosed by hyaline cells on the ventral surface. Dioicous; antheridial branches reddish, with club tips; perigonial leaves shorter and broader than vegetative branch leaves. Spores dark yellowish, papillose, 22–25 µm in diameter.
Chinese specimens examined: HEILONGJIANG: Da Xing An Ling (Greater Khingan Mt.), C. Gao 12755 (IFSBH, KUN, MO). JILIN: Chang-bai Mt., Yuan Chi, Vitt 34801, 34808 (ALTA, MO).
Habitat: in bogs and rich fens; Distribution: China, India, Japan, Russia (Siberia and Caucasus), Europe, Greenland, and North America.
Illustrations: C. Gao (ed.) 1994 (Pl. 19, figs. 1–6, as Sphagnum warnstorfianum).