Dicranum groenlandicum Bridel 1819

Dicranum groenlandicum is sometimes not very distinct, often being difficult to separate from its nearest relative, 19. D. elongatum. For distinctions see the discussion under that species.

Plants medium- to large-sized, 3–12 (–15) cm high, yellowish green or brownish green, shiny, in dense tufts. Stems erect, simple or branched, densely tomentose below the middle. Leaves erect, stiff, appressed when dry, erect-spreading when moist, narrowly to ovate-lanceolate, ca. 3.0 mm × 0.6–0.8 mm, gradually to rather quickly narrowed to a subtubulose acumen; margins plane below, slightly involute above, unistratose, nearly entire throughout; costa slender, occupying ca. 1/10 – 1/8 the leaf base width, smooth at back above, percurrent; upper cells rounded rhomboidal, thick-walled, somewhat porose; basal cells elongate, thick-walled, strongly porose; alar cells rounded quadrate, inflated, unistratose, golden brown. Dioicous. Setae slender, ca. 1.5 cm long, yellowish when young, brownish when old; capsules erect or slightly curved when dry, short-cylindric; opercula long-rostrate; annuli in 1–2 rows of large cells; peristome teeth divided to the middle, pale and smooth at tips, vertically striolate below, orange brown. Spores 20–24 µm in diameter, faintly papillose.

Plants in dense tufts, light green, glossy. Stems 4.5-10 cm, tomen-tose throughout with brown to red rhizoids. Leaves erect-spreading, erect-appressed when dry, smooth, (2.5-)3-4(-6.5) × 0.3-0.5 mm, from an ovate-lanceolate base to a tubulose subula, narrowly obtuse at apex, rarely acute, sometimes apical leaves of stems julaceous; margins entire; laminae 1-stratose, occasional 2-stratose regions near costa in proximal part of leaf; costa subpercurrent to percurrent, ¹/10-¹/6 the width of the leaves at base, smooth, abaxial ridges absent, with a row of guide cells, two well developed and thick stereid bands (5-6 cells thick), adaxial epidermal layer of cells not differentiated, the abaxial layer usually with a few cells enlarged; cell walls between lamina cells slightly bulging; leaf cells smooth; alar cells 1- or 2-stratose, well-differentiated, not extending to costa; proximal laminal cells elongate-sinuose, strongly pitted, (36-)54-65(-98) × (2-)5-6(-9) µm; distal laminal cells (11-)17-26(-42) × (2-)5-6(-12) µm. Sexual condition dioicous; male plants as large as females; interior perichaetial leaves abruptly short-acuminate, convolute-sheathing. Seta 1.5-2 cm, solitary, yellow to reddish yellow. Capsule 1.5-2 mm, nearly straight and erect to slightly arcuate, ± striate when dry, yellowish brown; operculum 1-1.7 mm. Spores 14-19 µm.

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

Habitat: on wet soil and rocks or mixed with peat mosses.

Dicranum elongatum Schleich. ex Schwaegr. ssp. groenlandicum (Brid.) Moenk., Laubm. Eur. 210. 1927. Dicranum elongatum var. sphagni T. Jens., Vidensk. Meddel. Dansk Naturhist. Foren. Kjobenhavn 1858(1–4): 58. 1858.