Dicranum frigidum C. Müller 1859

Dicranum frigidum C. Mull. Bot. Zeit. 17: 219. 1859
Dioicous: male plants minute, 2-3 mm. high, growing in clusters on the tomentum or sometimes on the older leaves of the fertile stems, the 5 or 6 antheridia with few paraphyses: fertile plants in extensive, soft mats, tomentose within, with robust stems up to 18 cm. high: stem-leaves up to 13 mm. long, often more or less undulate, spreading-flexuous, rarely somewhat falcate-secund at the apex of the stem, long-lanceolate, acute, sharply serrate on the margins one half down; costa just above its broadened base about 75 /* wide and one tenth the width of the leaf or less, ending just below the apex, with two sharply serrate ribs on the back above, in cross-section near the middle showing about 5 guide-cells with stereid-bands above and below, the lower band with 2 or 3 larger cells on the dorsal side; alar cells brown, extending half way to the costa, the cells above all elongate, with thickened, pitted walls extending to the apex, the lower cells about 12 p wide and 125 p long or more, the median ones 40-50 fi long; inner perichaetial leaves with a convolute base up to 9 mm. long, more or less costa te, abruptly narrowed to a slender point 2-4 mm. long, serrulate at the apex: setae aggregate, 1-4, dark-red, up to 6 cm. high: capsule cylindric, 3-5 mm. long, curved, nodding or horizontal, scarcely or not furrowed when dry, the exothecal cells with walls uniformly thickened, those on the convex side elongate, those on the incurved side and at the mouth of the capsule nearly square to hexagonal; annulus wanting; lid conic-rostrate, rather shorter than the capsule; peristometeeth reddish-brown, vertically striate, divided more than one half down, the inner plates with prominent articulations 20-25 n apart: spores rough, up to 25 p in diameter.
Type locality: Venezuela.
Distribution: Mexico and southward into South America.