4. Sphagnum capillifolium (Ehrh.) Hedw., Fund. Hist. Nat. Musc. Frond. 2: 86. 1782; Sphagnum palustre ssp. capillifolium Ehrh., Hannovr. Mag. 18: 235. 1780.
Sphagnum acutifolium Ehrh. ex Schrad., Spic. Fl. Germ. 58. 1794.
Sphagnum nemoreum Scop., Fl. Carniol., ed. 2, 305. 1772.
Plants variable in size and color, usually green to yellowish brown, somewhat tinged with pinkish color, sometimes distinctly reddish, not shiny when dry, in loosely compact tufts. Stem cortex in 2–4 layers, hyaline cells thin-walled, without fibrils and pores; central cylinder yellowish or light reddish. Stem leaves differentiated in size on the same stem, generally larger in the lower parts and smaller in the upper parts of the stems, 1.0–1.5 mm × 0.4–0.7 mm, oblong-ovate to oblong-isosceles-triangular, upper margins involute to a nearly cucullate apex; borders narrow above, clearly widened below; hyaline cells broad-rhomboidal in the upper parts of leaves, mostly divided, narrow-rhomboidal below, less divided, with large pores on both surfaces. Branches in fascicles of 3–5, with 2–3 spreading. Branch leaves 0.9–1.4 mm × 0.4–0.5 mm, ovate-lanceolate, upper margins involute, with blunt, dentate apex; hyaline cells densely fibrillose, upper cells with pores at ends and at corners, lower cells and marginal cells with large pores on ventral surface, with numerous, ringed, elliptic pores in the upper cells, gradually enlarged in the lower cells on the dorsal surface; green cells in cross section triangular, exposed on the ventral surface. Dioicous or monoicous; branches with antheridia reddish; perigonial leaves short and broad with abruptly narrowed apex. Perichaetial leaves broadly ovate, abruptly involute-concave at the apex. Spores pale-yellowish, smooth or slightly papillose, 20–25 µm in diameter.
Chinese specimens examined: HEILONGJIANG: Da Xing An Ling (Greater Khingan Mt.), C. Gao 150, 13018 (IFSBH, KUN); Xiao Xing An Ling (Lesser Khingan Mt.), S.-E. Liu 8748, 8894 (KUN), D.-Z. Huang 149 (KUN). JILIN: An-tu Co., Koponen 36960 (H, MO); Changbai Shan (Mt.), S.-E. Liu 8814 (IFSBH, KUN), Y.-L. Zhou 767 (IFSBH, KUN), Vitt 34803 (MO); E-mu Co., X.-W. Kong 2255 (KUN). NEI MONGOL: Da Xing An Ling (Greater Khingan Mt.), P.-C. Chen 158 (KUN); C. Gao 3612 (IFSBH, KUN); C.-Q. Lin 1949, 2138 (IFSBH, KUN); H.-F. Xie 26 (KUN); Y.-L. Zhang 81, 85 (IFSBH, KUN); Gen-he Forest Region, H.-F. Xie 12 (KUN). XINJIANG: Altai Shan (Mt.), J.-C. Zhao 1742, 1840 (KUN); Bur-qin Co., B. C. Tan 93-917 (FH, MO). XIZANG: Cawarong, L.-S. Wang 636, 1189 (KUN); Mo-tou Co., Y.-G. Su 1066 (KUN, MO), 5082 (KUN). YUNNAN: Gong Shan (Mt.), D.-C. Zhang 476 (KUN), 643 (KUN, MO); Yang-bi Co., W.-M. Zhu 636 (KUN).
Habitat: in peatland under conifers or Rhododendron brush, on wet humus and the sides of hummocks; Distribution: China, India, Korea, Japan, Russian Far East, Europe, North and South America, and Africa.
This species shows great variation. Numerous varieties have been published under this species complex. A clear distinction among the complex is difficult to make. Several varieties in the complex sometimes show their variation beyond species level. For example, when Warnstorf (1911) described the character of pore formation in Sphagnum capillifolium, he included nearly every type of pore formation found in the genus. In addition, certain authors consider the slender plants with pinkish to reddish color to be within the variation of this species. Thus, a number of species have been mistakenly included under synonymy of this species. A differentiation of the border of stem leaves is, however, a relatively stable feature. This feature is the same as that of Sphagnum girgensohnii and S. russowii. The latter two species differ in having their stem leaves broadly ligulate with flat, truncate leaf apices, while the stem-leaf apex in Sphagnum capillifolium is gradually acute and involute-cucullate.
Illustrations: C. Gao (ed.) 1994 (Pl. 6, figs. 13–17, as Sphagnum nemoreum).