Sphagnum cyclophyllum Sullivant & Lesquereux ex A. Gray 1856

Sporophytes are quite rare in Sphagnum cyclophyllum, which grows associated with S. pylaesii, S. perichaetiale, S. portoricense, and S. lescurii. Sphagnum pylaesii is the only other North American Sphagnum that regularly grows unbranched. The latter species not only lacks the typical sect. Subsecunda branch leaf porosity of S. cyclophyllum but is also much more slender. Sphagnum pylaesii is also much more likely to occur submersed, where it occurs in branched forms, something S. cyclophyllum rarely does. See also discussion under 57. S. microcarpum and 61. S. platyphyllum.

Plants low, erect or procumbent, loosely tufted; green or more frequently yellowish, orangish brown-red, reddish brown or dark red; capitulum not developed. Stems brown to black; superficial cortex of 1 (-2) layers of enlarged, thin-walled cells. Stem leaves broadly ovate, 3.5-4 mm, apex rounded and indistinctly toothed; hyaline cells on convex surface with 10-20 small (2.5-7.5 µm) round pores approximately ¹/6 the diameter of the hyaline cells along the commissures, cells on concave surface uniporose in distal end or aporose, sometimes one or a few pores are scattered over the surface of the cells. Branches few, single and short or more commonly none. Branch fascicles, if any, usually only 1 single branch. Branch leaves if any, are usually slightly smaller, 2-3 mm, but otherwise identical to the stem leaves. Sexual condition dioicous. Capsule immersed in perichaetial leaves, pseudopodium extremely short, without pseudostomata. Spores 25-40 µm; coarsely papillose on both surfaces; proximal laesura more than 0.5 the length of the spore

Sphagnum cyclophyllum Sull. & Lesq.; Sull. in A. Gray,
Man. ed. 2. 611. 1856.
Sphagnum microcar pum Wamst. Hedwigia 30: 170. 1891. Sphagnum Alabamae Wamst. Hedwigia 47: 94. 1907.
Plants low, erect or procumbent, green or more or less tinged with brown. Wood-cylinder generally brown; cortical cells of the stem in 1-2 layers, very large and thin-walled, the outer cells quadrilateral, generally longer than wide, often with a pore in the upper end; stem-leaves isophyllous, as branches are usually lacking, or if present mostly single, thick, ascending: leaves oval to ovate, faintly toothed across the rounded apex, the border weak, of 1-2 rows of narrow cells; hyaline cells fibriUose throughout, 10-12 times as long as wide in the central portion, shorter toward the base and apex to 5-6 times, on the inner surface mostly with a few pores in the ends and comers of the cells, 2-5 per cell, on the outer surface with very minute round pores near the commissures, up to 20 or more per cell, sometimes reduced in number or larger in size: chlorophyl-cells in section mostly trapezoidal with broader exposure on the inner surface, the lumen triangular, the walls thin; hyaline cells not convex on the inner surface, very slightly so on the outer, not more than ore eighth to one sixth of the diameter of the cell.
Dioicous. Fruiting branches short; perichaetial leaves large, ovate, with both kinds of cells throughout, the hyaline cells all fibriUose: capsule rather small, dark-brown; pseudopodium short; wall of the capsule with or without pseudostomata : spores yellow, 25-35/1 in diameter, granular-roughened.
Type locality: Alabama.
Distribution: New Jersey to Florida, Alabama, and Louisiana; also in Brazil.

Sphagnum cyclophyllum là một loài rêu trong họ Sphagnaceae. Loài này được Sull. & Lesq. mô tả khoa học đầu tiên năm 1856.