Dicranum Moss

Plants medium-sized to moderately large, 2–5 cm high, dull green to brownish or dark brown, not or only slightly shiny, in dense tufts. Stems erect or ascending, simple or branched from the base, densely tomentose below. Leaves usually crispate when dry, falcate-secund, or flexuose to erect-spreading when moist, narrowly lanceolate, 4–7 mm long, gradually narrowed to a slender, somewhat keeled acumen; margins plane, entire below, serrulate to double-toothed above the middle part of leaves; costa stout, occupying ca. 1/6 – ¼ the leaf base width, shortly excurrent, often serrulate at back in the upper half; upper cells subquadrate to short-rectangular, 8–12 µm wide, moderately thick-walled, smooth or occasionally projecting on the leaf dorsal surface; basal cells rectangular, thick-walled, more or less pitted; alar cells clearly inflated, brownish, thin-walled, occasionally bistratose, not extending to the costa. Dioicous. Male plants normal. Perichaetial leaves high convolute-sheathing, abruptly subulate. Setae single, 1.2–2.5 cm long, yellowish brown to reddish brown, twisted when dry; capsules inclined to horizontal, short-cylindric, 1.7–3.0 mm long, curved, asymmetric, often somewhat strumose and furrowed when dry; opercula obliquely long-rostrate, nearly as long as the urns; annuli in 2 rows of large cells; stomata few; peristome teeth ca. 0.5 mm long, irregularly 2–3 divided to the middle, reddish brown, papillose above, vertically striolate below. Spores 15–20 µm in diameter.

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

Habitat: on bases of trees, rotten logs, or rocks.

Dicranum scoparium (Hedw.) var. fuscescens (Turn.) Weber & Mohr, Bot. Taschenb. 174. 1807. Dicranodon scoparium (Hedw.) var. fuscescens (Turn.) Béhéré, Muscol. Rothom. 29. 1826. Dicranum congestum ssp. fuscescens (Turn.) Amann, Fl. Mouss. Suisse 2: 56. 1919. Dicranum congestum Brid., Muscol. Recent. Suppl. 1: 76. 1806. Dicranum fuscescens ssp. congestum (Brid.) Kindb., Bih. Kongl. Svenska Vetensk.-Akad. Handl. 7(9): 93. 1883. Dicranum fuscescens var. congestum (Brid.) Husn., Muscol. Gall. 34. 1884.