Delicate Peatmoss

This species is similar to Sphagnum cuspidatulum, but it differs in the following features: 1) plants smaller; 2) stem leaves oblong-ligulate; 3) branch leaves broadly ovate to oblong-ovate; and 4) the hyaline cells of branch leaves with pores only at the opposite corners. In contrast, Sphagnum cuspidatulum has the following features: 1) plants larger and stouter; 2) stem leaves triangular; 3) branch leaves ovate-lanceolate; and 4) the hyaline cells of branch leaves with pores at the corners and along commissural rows.

Sporophytes are common in Sphagnum tenellum. The delicate appearance created by the ovate and concave branch leaves as well as the large concave stem leaves make this a usually unmistakeable species.

Plants slender, rather soft, grayish green or yellowish brown, in loose cushions. Stem cortex in 2–3 layers, hyaline cells large, thin-walled, without fibrils and pores; central cylinder yellowish green. Stem leaves 1.0–1.4 mm × 0.5–0.6 mm, relatively large, oblong-ligulate, rounded-obtuse, often lacerate across the apex; borders narrow above, slightly widened near the base; hyaline cells usually not divided, fibrillose in the upper half or nearly to the base, with pores at the upper and lower corners and with ringed pores at the opposite sides along commissural rows on the dorsal surface, with pores at the opposite corners on the ventral surface. Branches in fascicles of 2–4, with 1–2 spreading. Branch leaves 1.0–1.5 mm × 0.5–0.6 mm, broadly ovate to oblong-ovate, concave, secund when dry, blunt and dentate at the apex; hyaline cells narrowly rhomboidal, densely fibrillose, with pores at the upper and lower corners and with ringed pores at the opposite sides along commissural rows on the dorsal surface, with pores at the opposite corners on the ventral surface; green cells in cross section triangular or trapezoidal, exposed on the dorsal surface, enclosed by hyaline cells or slightly exposed on the ventral surface. Dioicous; antheridial branches yellowish brown. Perigonial leaves similar to vegetative branch leaves in size and shape, yellowish brown. Perichaetial leaves large, concave, dentate at the apex; hyaline cells rarely fibrillose, with pores similar to those of stem leaves. Capsules small. Spores yellowish, smooth, ca. 38 µm in diameter.

Plants small, slender and weak-stemmed; pale yellow to golden brown, rarely tinged with red; capitulum not especially distinct. Stems pale green to pale brown; superficial cortex of 2-3 layers of enlarged thin-walled cells. Stem leaves ovate-lingulate; 1-1.3 mm, apex broadly rounded; hyaline cells nonseptate, aporose and fibrillose in at least distal half of leaf. Branches 2-3 spreading and 2 pendent leaves not much elongated at distal end. Branch stems green; cortex enlarged, with conspicuously long-necked retort cells. Branch leaves ovate, 1-1.5 mm; straight; not or weakly undulate or recurved when dry; margins entire; hyaline cells short and wide, convex surface with 1-3 small pores per cell and on concave surface with large round wall thinnings in the cell angles; chlorophyllous cells equilateral-triangular in transverse section, broadly exposed on convex surface and just reaching to well-enclosed on concave surface. Sexual condition monoicous. Spores 27-42 µm; both surfaces smooth, proximal surface with distinct bifurcated Y-mark sculpture surrounded by distinct circular border, distal surface with distinct raised border around margins; proximal laesura usually less than 0.4 spore radius.

Distribution: China, India, Japan, Europe, North America, and North Africa.

Habitat: on wet ground under forests or near streams; also in bogs or on grasslands.

Sphagnum molluscum Bruch, Flora 8: 635. 1825.

Sphagnum cymbifolium var. tenellum Bridel, Musc. Recent. 2(1): 24. 1798; S. molluscum Bruch