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FNA | Family List | FNA Vol. 27 | Sphagnaceae | Sphagnum

1d. Sphagnum sect. Squarrosa (Russow) Schimper, Syn. Musc. Eur. ed. 2. 835. 1876.

Sphagnum [unranked] Squarrosa Russow, Beitr. Torfm., 33. 1865

Plants moderate-sized to robust, with distinct capitulum; green,yellowish brown. Stems green to dark reddish brown, superficial cortex of 2-4 layers of efibrillose, non-ornamented, enlarged, thin-walled, aporose, rectangular cells. Stem leaves ovate, ovate-lingulate to lingulate; with broad, fringed apex; little or no border along margins or base; hyaline cells rhomboid, efibrillose, non-ornamented, aporose, usually nonseptate, with resorption gaps on exterior surface. Branches strongly dimorphic, pendent branches thinner but about same length as spreading branches. Branch stems green, with cortex surrounded by 1-2 layers of efibrillose, non-ornamented, enlarged, thin-walled cells, some cells apically porose with inconspicuous necks. Branch leaves strongly squarrose or spreading, ovate, ovate-hastate or ovate-lanceolate, margins entire, apex involute and smooth; hyaline cells fibrillose; with large, round pores at cell ends and along commissures, sometimes with faint papillae on interior walls; chlorophyllous cells ovate-triangular, elliptical to ovate-elliptical in transverse section, more broadly exposed on convex surface, end walls not thickened. Sexual condition monoicous or dioicous. Capsule 2 mm or more, with scattered pseudomata. Spores less than 30 µm, both surfaces smooth to finely papillose; proximal laesura more than 0.5 spore radius.

Species 4 (4 in the flora): North America, Eurasia, Pacific Islands (New Zealand).

1 Branch leaves markedly truncate; chlorophyll cells ovate-triangular in transverse section, with the widest part at or near the convex surface.   19 Sphagnum tundrae
+ Branch leaves not truncate; chlorophyll cells elliptical to elliptical-ovate with the broadest part typically some distance from the convex surface   (2)
2 (1) Branch leaves strongly squarrose (terete in tundra forms), large (1.9-3 mm); hyaline cells of branch leaves with ringed elliptic pores on concave surface and unringed pores on convex surface; stem leaves 1/2-2/3 as long as branch leaves (1.1-1.9 mm)   17 Sphagnum squarrosum
+ Branch leaves imbricate (squarrose in shade forms), moderate in size (1-1.5 mm); hyaline cells of branch leaves with unringed pores on concave and convex surfaces; stem leaves as long or longer than branch leaves (1-1.7 mm)   (3)
3 (2) Branch leaf hyaline cells near leaf base on convex surface mostly aporose and on concave surface with large, faint pores; 1-2 hanging branches.   16 Sphagnum mirum
+ Branch leaf hyaline cells near leaf base on convex surface with large, round pores and on concave surface mostly aporose; 2-3 hanging branches.   18 Sphagnum teres

Lower Taxa


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