Dicranum Moss

Dicranum spurium is easily recognized by the turgid aspect of the plants with arched, imbricate leaves and with interruptedly foliate stems, i.e., some regions that appear swollen or globose as a result of several growth periods. It is likely to be confused only with 11. D. condensatum (see discussion thereunder).

Plants medium-sized to moderately large, 2–5 cm high, rather robust, dull, yellowish green or yellowish brown, not shiny, in loose to dense tufts. Stems erect, usually branched, rarely simple, often interruptedly foliate, moderately tomentose below. Leaves crowded or loosely imbricate, falcate-secund to crispate when dry, erect-spreading when moist, usually undulate, ovate-lanceolate, 3–5 mm × 0.8–1.2 mm, contracted at base, gradually narrowed above the middle from an ovate base, to a short, broadly acuminate apex; margins plane, entire below, serrulate in the upper 1/3; costa rather stout, percurrent or nearly so, serrate or ridged at back above; upper cells small, rounded quadrate or irregularly quadrate, thick-walled, somewhat porose, often strongly papillose or projecting at back; basal cells elongate, linear-rhomboidal, ca. 80 µm × 14 µm, thick-walled, porose; alar cells weakly differentiated, quadrate or short-rectangular, usually bistratose, brownish, not extending to the costa. Dioicous. Male plants dwarfed. Setae single, pale brownish, 12–24 mm long; capsules oblong-ovoid, 1.7–2.3 mm long, curved, asymmetric, inclined to horizontal, furrowed when dry and empty, strumose at base; stomata present; opercula conic-rostrate; annuli in 2 rows of large cells, revoluble; peristome teeth ca. 0.5 mm long, 2–3 divided to the middle, deep brownish, papillose above, transversally barred below. Spores 20–24 µm in diameter, brownish.

Plants in loose tufts, green to yellowish green or yellowish brown, dull. Stems 2-11 cm, densely tomentose below with reddish brown rhizoids, inter-ruptedly foliate, the leaves crowded in some parts forming swollen, globose regions. Leaves erect-spreading, arched and loosely imbricate with contorted apices when dry, ± undulate to rugose, (2.5-)5-6.5(-9) × 1-1.7 mm, concave below, tubulose above, acute, ovate at base, widest point at or somewhat below middle; margins serrulate to serrate in distal half, plane to involute; laminae 1-stratose or with 2-stratose regions near costa and on margins; costa percurrent to shortly excurrent, ¹/8-¹/4 the width of the leaves at base, serrulate or toothed above on abaxial surface, abaxial ridges absent, with a row of guide cells, two stereid bands extending to apex, adaxial epidermal layer of cells not differentiated, the abaxial layer differentiated; cell walls between lamina cells weakly to strongly bulging; leaf cells strongly papillose above on abaxial surface, sometimes a few papillae on adaxial surface; alar cells 2-stratose, distinctly differentiated, not extending to costa; proximal laminal cells elongate, pitted, (30-)49-68(-101) × (5-)10-11(-15) µm, abruptly shorter in distal half of leaf; distal laminal cells short, not or indistinctly pitted, cell walls irregularly thickened, (7-)11-12(-23) × (5-)7-13(-20) µm. Sexual condition pseudomonoicous; dwarf males on rhizoids of female plants; interior perichaetial leaves abruptly short-acuminate, convolute-sheathing. Seta 1-3 cm, solitary, reddish yellow or brown. Capsule 1.5-2.5 mm, arcuate, inclined to horizontal, contracted below mouth and furrowed when dry, yellowish brown to brown; operculum 1.5-2.5 mm. Spores 16-24 µm.

Distribution: China, Korea, Japan, Russia, Europe, and North America.

Habitat: on peat lands or grasslands.

Bryum spurium (Hedw.) Dickson, Fasc. Pl. Crypt. Brit. 4: 13. 1801. Cecalyphum spurium (Hedw.) P. de Beauv., Prodr. Aetheogam. 51. 1805.