2. Sphagnum angustifolium (C. Jens. ex Russ.) C. Jens., Bih. Kongl. Svenska Vetensk.-Akad. Handl. 16. 3(9): 46. 1891; Sphagnum recurvum ssp. angustifolium C. Jens. ex Russ., Sitzungsber. Naturf.-Ges. Dorpat 9: 112. 1890.
Plants small, green to yellowish brown; capitula often small, not distinct radiate. Stem cortex in 1 layer, sometimes not well developed, hyaline cells lacking fibrils; central cylinder yellowish green. Stem leaves 0.5–0.8 mm × 0.5–0.7 mm, flat, nearly equilateral-triangular, slightly dentate or erose at a broadly acute apex; borders differentiated, slightly widened at the base; hyaline cells lacking fibrils, only divided at leaf base, generally without pores. Branch leaves ca. 1.1–1.4 mm × 0.3–0.4 mm, lanceolate, crowded and imbricate, spirally arranged when moist, not or only slightly undulate when dry, dentate and truncate at the apex; green cells in cross section triangular, exposed on the dorsal surface, slightly reaching the ventral surface; hyaline cells with large pores at
the upper ends and a few small pores at the corners and along commissures on the dorsal surface, those from pendent branch leaves with numerous pores on the ventral surface. Dioicous. Sporophytes not seen.
Chinese specimens examined: HEILONGJIANG: Hong Xing, Vitt 34886 (ALTA, MO, mixed with Sphagnum magellanicum). JILIN: Changbai Shan (Mt.), Yuan Chi (lake), Vitt 34806 (ALTA, MO).
Habitat: in peatland under open forests; Distribution: China, Korea, Japan, Russian Far East, Europe, and North America.
Illustrations: Crum 1984 (Fig. 23, d–f, as Sphagnum recurvum var. tenue).