Dicranum fuscescens

Plants light green to dark brownish green, dull, in loose tufts. Stems 1–6(–18) cm, tomen-tose 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.

Distribution

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File:V27 583-distribution-map.gif, File:V27 583-distribution-map.jpg

North America, Europe, Asia.

Discussion

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

Selected References

None.

Lower Taxa

Dicranum fuscescens var. flexicaule, Dicranum fuscescens var. fuscescens

Key

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