Low Sphagnum Moss

This species is characterized by having very crowded, stout and blunt branches, very small stem leaves that are about 1/8 – 1/6 of the length of branch leaves, and by the green cells of branch leaves centrally located.

Sphagnum compactum is usually easily recognized by its combination of golden brown color and involute, cucullate branch leaves. Sphagnum strictum is paler and usually strongly squarrose.

Plants stout in dense or compact tufts, grayish to yellowish green or tinged with pinkish red. Stem cortex in 2–3 layers, hyaline cells large, thin-walled, without fibrils, with a single pore; central cylinder yellowish brown. Stem leaves 0.50–0.55 mm × 0.6 mm, triangular-ligulate, with rounded, involute, often lacerate apices; borders clearly widened at leaf base, occupying about 1/6 leaf width; hyaline cells rhomboidal, not divided, without fibrils, with pores only on the ventral surface. Branches short, stout, and crowded in fascicles of 4–6 with 2–3 spreading. Branch leaves 1.6–2.6 mm × 0.8–1.6 mm, broadly ovate, several times larger than stem leaves, concave with involute-concave apex; borders indistinct, sometimes denticulate along margins; hyaline cells densely fibrillose, with numerous pseudopores, 2–3 pores at the corners of each cell on the ventral surface, few to numerous rather larger pores at the ends on the dorsal surface; green cells in cross section small, narrowly oval to elliptic, centrally located or slightly widened toward the dorsal surface, enclosed by hyaline cells on both surfaces. Monoicous. Perigonial leaves not differentiated. Perichaetial leaves broadly ovate to oblong ovate, subsecund, concave. Spores yellowish brown, 32–35 µm in diameter.

Plants moderate to large-sized, dense and compact, pale green, brownish white, golden brown to variegated golden brown, can be reddish in rocky seep habitats; forms small, tufted compact cushions. Stems brown. Stem leaves small, 0.3-0.7 mm, triangular-lingulate with broad rounded apex, Branches short, crowded, and unranked. Branch fascicles 4-6 branches per fascicle, 2-3 spreading and 2-3 pendent, but plants frequently unbranched in young clones. Branch leaves large, 1.4-3 mm, semi-squarrose to squarrose, ovate and abruptly involute in distal portion, appearing cucullate with toothed apex, usually no more than 6 teeth; hyaline cells with 5 or more ringed, round to elliptical pores on convex surface, numerous pseudopores on concave surface with 3-ringed corner pores occurring in 3s at adjacent cell angles; chlorophyllous cells elliptic in transverse section, entirely included by hyaline cells, slightly nearer to convex surface. Sexual condition monoicous. Capsule with abundant pseudostomata. Spores 25-35 µm; finely papillose on proximal surface, coarsely papillose on distal surface with raised Y-mark sculpture; proximal laesura short, 0.3-0.5 spore radius.

Distribution: China, Southeast Asia, Russian Far East, Europe, North America, North Africa, and Australia.

Habitat: on moist ground under forests or on rocks with dripping water in high mountains.

Sphagnum compactum var. imbricatum Warnst., Bot. Gaz. 15: 226. 1890.

Sphagnum compactum var. imbricatum Warnstorf; S. rigidum (Nees & Hornschuch) Schimper

Sphagnum compactum DC. Fl. Fr. 2 : 443. 1805
sphagnum rigidum Schimp. M6m. Sphaig. 72. 1857.
Plants short and compact, rarely taller and somewhat robust, dirty-white, especially when dry, or sometimes with a brownish tinge or partly or entirely green. Wood-cylinder brown; cortical ceUs of the stem in 2-3 layers, large, with thin walls, without fibrils, the outer cells quadrilateral to pentagonal, sometimes longer than wide, without pores: stem-leaves minute, concave, short-Iingulate to triangular-Ungulate, sometimes more or less lacerate at the apex; hyaline cells without fibrils or divisions, on the inner surface with a membrane-gap in the upper end of each cell, small and rounded or toward the apex of the leaf irregular in shape and often occupying a large part of the cell, the membrane of the outer surface without pores, hut with longitudinal membrane-pleats, the cell-waUs pitted, especially in the narrow cells of the margin: branches short, compactly arranged in close fascicles of 4 or 5, 2 stronger, spreading or ascending, rigid, the others pendent; their cortical cells in a single layer, without fibrils, the apex of each cell produced outwardly inio a slight neck which ends in a pore : branchleaves imbricate to strongly squarrose, large, ovate-hastate, slightly denticulate on the edge, involute, ending in a truncate toothed apex; hyaline cells strongly fibrillose, irregularly hexagonal-rhomboidal, 6-8 times as long as wide at the base, shorter above to twice as long as wide in the apex, on the inner surface with ringed pores in the cell-angles, generally then in threes in adjacent comers, commonly 3 in each cell, on the outer surface with very numerous large rounded pores near the commissures, mostly included within a larger fibrilring, 4-8 per cell besides many such fibril-rings without perforation (pseudopores) ; chlorophylcells in section elliptic, central or nearer the outer surface, entirely included; inner walls of hyaline cells smooth; hyaline cells not at all or very slightly convex on the outer surface, more so on the irmer where up to one fifth of the diameter of the cell ; resorption-furrow present.
Monoicous and often fruiting. Antheridia few on undifferentiated pendent or spreading branches. Fruiting branches erect with few large subsecund perichaetial leaves, the latter ovate-lanceolate, long-acuminate, the tip consisting entirely of narrow cells with pitted walls, which type of cells is continued downward in a narrow border, the rest of the leaf composed of chlorophyl-cells and hyaline cells with fibrils and pores much as in ordinary branch-leaves, the non-fibrillose cells sometimes showing a membrane-gap in the center of the inner surface ; chlorophyl-cells nearer the outer surface, where sometimes slightly exposed ; resorption-furrow lacking: capsule small on a slender pedicel, brown: spores brown-yellow, 24-28 /x in diameter, slightly granular-roughened.
Type locality: France.
Distribution: Greenland; Labrador southward to Florida and Alabama; Illinois; Vancouver Island to Alaska; also in Europe and Asia.

Sphagnum compactum, the compact bogmoss, is a species of moss belonging to the family Sphagnaceae.

It has cosmopolitan distribution.