Dicranum arcticum

Dicranum arcticum Schimp. Musci Eur. Novi (3-4:)
Dicranum 3. 1866.
Dicranum Starkii molle Wilson, Bryol. Brit. 74. 1855.
Dicranum molle Wilson (Bryol. Brit. 75, as synonym. 1855); Lindb. Musci Scand. 24. 1879.
Autoicous: plants in extensive, deep tufts, usually dark-brown within and olive-green at the surface; stems without radicles, 6-15 cm. high, mostly simple and erect with leaves straight and spreading, or sometimes curved-secund toward the apex: stem-leaves 5-7 mm. long, subtubulose, from an ovate-lanceolate base gradually narrowed to a subulate point with the leaf-margins entire to distantly crenulate from near the base to the apex; costa excurrent, at the base 40-60 fx wide, about one tenth the width of the leaf-base, in cross-section showing all the cells with walls of uniform thickness but the median row of 4-7 rather larger cells; leafcells, except the alar, linear throughout, with thickened walls more or less pitted in the lower ones, the median about 6 n wide by 40-60 /j, long; alar cells forming a nearly square, reddishbrown, sometimes inflated and auriculate group; inner perichaetial leaves rather shorter than the stem-leaves with leaf-cells broader, costa narrower and leaf above abruptly narrowed to a nearly smooth point scarcely as long as the broadly ovate base: seta brownish, 15 mm., rarely 25 mm. long: capsule 2 mm. long, nodding, curved, mostly distinctly strumose and ribbed when dry; exothecal cells irregularly elongate with unequally thickened walls; stomata at the base of the capsule in mostly one row; peristome-teeth 50-60 /x wide at the base, the outer plates 8-12 n high, vertically striate, the inner plates, one fourth up, 25-30 n high, papillose; annulus of about 3 rows of cells; lid obliquely rostrate: calyptra nearly smooth at the apex: spores roug , 1 6 [i in diameter.
Type locality: Norway. t m
Distribution: Greenland, Labrador, and the Yukon region; also in Europe and Asia.