Warnstorf's Sphagnum

Sporophytes are uncommon in Sphagnum warnstorfii. This is one of the most minerotrophic species of the flora, is hygrophytic, and has a very broad niche. The most commonly associated vascular plants are Thuja occidentalis, Abies balsamea, and Picea rubens. Bryophytes typically associated with it are S. centrale, S. squarrosum, S. teres, Calliergonella cuspidata, and Campylium stellatum. This species is perhaps most similar to S. bartlettianum, with which it has small range overlap. Sphagnum warnstorfii has a shorter and less sharply pointed stem leaf and the red color with a characteristic bluish caste compared to the crimson red of S. bartlettianum. See also discussion under 81. S. russowii and 86. S. talbotianum.

Plants small or less frequently moderate-sized, slender, capitulum flat-topped and stellate; green or dark purplish red and green, rarely green throughout, often with a distinctive bluish cast when dry. Stems red to green; superficial cortical cells aporose. Stem leaves triangular-lingulate to lingulate, 1.1-1.4 mm, apex broad-rounded to narrowly truncate, border very broad at base (more than 0.3 width); hyaline cells efibrillose, rhombic, mostly 1-septate but can be non-septate. Branches long and tapering, usually strongly 5-ranked. Branch fascicles with 2 spreading and 1-2 pendent branches. Branch leaves ovate-lanceolate, 0.9-1.4 mm, concave, straight, apex involute; hyaline cells on convex surface with very small ringed pores (less than 0.25 cell width) along commissures near apex, changing abruptly to large elliptical pores (0.4 cell width or more) basally, concave surface with large round pores in proximal margins and leaf base. Sexual condition dioicous. Spores 17-26 µm, finely papillose on both surfaces; proximal laesura less than 0.5 spore radius.

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.

Distribution: China, India, Japan, Russia (Siberia and Caucasus), Europe, Greenland, and North America.

Habitat: in bogs and rich fens.

Sphagnum warnstorfianum Du Rietz

Sphagnum warnstorfianum Du Rietz in Sjörs, Svensk. Bot. Tidskr. 38: 405. 1944 [1945], nom. superfl.