Muscol. Hibern. Spic., 60, plate 5, fig. 1. 1804,.
Plants light green to dark brownish green, dull, in loose tufts. Stems 1–6 (–18) cm, tomentose to scarcely tomentose with white or reddish-brown rhizoids. Leaves falcate-secund, often strongly so, sometimes somewhat sparse, distal leaves curled, proximal leaves with flexuose apices, slightly to strongly curled and crisped when dry, smooth, (3–) 4–7 (–10) × 0.6–1 mm, concave below, keeled above, from a lanceolate base to a gradually narrowed, fine, keeled subula; margins entire proximally, serrulate to strongly serrate in the distal half, sometimes nearly entire throughout; laminae 1-stratose and usually 2-stratose above on one or both margins, rarely some 2-stratose regions near costa; costa excurrent, 1/6–1/4 the width of the leaves at base, strong, terete, papillose to spinose distally on abaxial surface, occasionally almost smooth, sometimes extending to costa, abaxial ridges absent, with a row of guide cells, 2 well-developed stereid bands extending to distal part of leaf, adaxial epidermal layer of cells not differentiated, abaxial epidermal layer differentiated; cell-walls between lamina cells slightly bulging; leaf cells smooth to slightly papillose below on abaxial surface, papillose to spinose prorate above on abaxial surface; alar cells 2-stratose, strongly differentiated, sometimes extending to costa; proximal laminal cells elongate, pitted, (19–) 43–62 (–93) × (2–) 6–8 (–12) µm; distal laminal cells irregularly rounded, elliptic, short-rectangular to quadrate, not pitted, (7–) 9–23 (–36) × (4–) 8–12 (–14) µm. Sexual condition dioicous; male plants as large as females, growing intermixed, or in separate patches; interior perichaetial leaves abruptly short-acuminate, convolute-sheathing. Seta 1–3.5 cm, solitary, yellow, reddish yellow or brown. Capsule 1–3 mm, arcuate, inclined to horizontal, strumose, strongly furrowed when dry, somewhat contracted below mouth, dark-brown to reddish-brown; operculum 1–2 mm. Spores 14–24 µm.
North America, Europe, Asia
Varieties ca. 7 (2 in the flora).
l. Plants small, stems 1–6(–10) cm, usually densely foliate; leaf margins serrulate to strongly serrate in distal half; costa papillose to spinose distally on abaxial surface; distal laminal cells short-rectangular to quadrate, mostly 18–23 µm long; seta mostly shorter than 2.5 cm
15a. Dicranum fuscescens var. fuscescens
|1||Plants small, stems 1-6(-10) cm, usually densely foliate; leaf margins serrulate to strongly serrate in distal half; costa papillose to spinose distally on abaxial surface; distal laminal cells short-rectangular to quadrate, mostly 18-23 µm long; seta mostly shorter than 2.5 cm||Dicranum fuscescens var. fuscescens|
|1||Plants large, stems 8-18 cm, sparsely foliate; leaf margins nearly entire; costa almost smooth on abaxial surface; distal laminal cells irregularly rounded, elliptic or short- rectangular, mostly 9-19 µm long; seta usually 2.5 cm long or more||Dicranum fuscescens var. flexicaule|