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Dicranum hyperboreum

Comprehensive Description

provided by North American Flora
Dicranum hyperboreum (Gunn.) Smith, Fl. Brit. 1227. 1804
Bryum hyperboreum Gunn. Fl. Norv. 2: 138. 1772. Dicranella cerviculalula Kindb. Ottawa Nat. 5: 195. 1892.
Autoicous: male flower on the stem somewhat below the perichaetium : plants in dark-
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green, compact tufts often blackish within; stems 2-3 cm. high, more or less branching and radiculose: leaves erect-flexuous, somewhat incurved when dry, spreading when moist; lower leaves small, the upper larger, 3-4 mm. long, from an ovate-lanceolate base with incurved blade and not quite entire margins, gradually narrowed to a slightly crenate-serrulate point; costa 65-80 fx wide at the base, about one sixth the width of the leaf-base, often slightly papillose on the back, rather long excurrent; leaf-cells with thickened walls, those in the upper part of the blade rectangular to nearly square, 8-10 n wide by 10-20 p long, the alar cells often not very distinct or sometimes forming a distinct group of larger, colored cells; perichaetial leaves loosely sheathing, the inner 4—5 mm. long, rather gradually narrowed to a not quite entire point scarcely equaling the basal part in length: seta stout, erect, 5-8 mm. high: capsule oblong, furrowed when dry and empty, about 1.5 mm. long by 1 mm. in diameter; exo thecal cells irregular, with unequally thickened walls, the median ones up to 20 fx wide by 80-100 n long, with stomata about 35 fj, by 45 p, in one row near the base of the spore-sac; annulus large, compound; peristome-teeth mostly divided to below the middle, at the base 100-115 ]x wide; lid convex, with an oblique beak, in height rather exceeding its basal diameter: calyptra smooth: spores rough, up to 28 x in diameter.
Type locality: Norway.
Distribution: Greenland and Labrador; Mount Hood, Oregon; also in northern Europe.
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bibliographic citation
Robert Statham Williams. 1913. (BRYALES); DICRANACEAE, LEUCOBRYACEAE. North American flora. vol 15(2). New York Botanical Garden, New York, NY
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