Orthotrichum Moss

Orthotrichum pumilum Dicks. PI. Crypt. Brit
4:5. 1801.
Orthotrichum affine /3 pumilum Hook. & Tayl. Muse. Brit. 74. 1818.
Orthotrichum infiexum C. Mull. Syn. 1: 690. 1849.
Orthotrichum Schimperi Hammar, Monogr. Orthotr. Ulot. Suec. 9. 1852.
Orthotrichum fallax Schimp. Syn. 264. 1860.
Orthotrichum brachytrichum Schimp.; Lesq. & James, Proc. Am. Acad. 14: 140. 1879.
Orthotrichum fallax var. truncatulum Aust. Bull. Torrey Club 6: 344. 1879.
Plants in short, close, dark green tufts, 1 cm. or less high; leaves imbricate when dry, not contorted, broadly to narrowly oblong-lanceolate, acute to narrowly obtuse, often apiculate with usually a single subhyaline cell at the apex, ± 2 mm. long, the margins revolute nearly to the apex; costa ending below the apex; upper leaf-cells larger and less dense than in most species, the walls thinner, slightly collenchymatous, 12-16 u in diameter, irregularly roundedhpvao-rmfll nanillose with low Daoillae. the basal cells smooth, oblong-rectangular near the costa to quadrate on the margins; autoicous; seta about 0.5 mm. long, together with the broad neck of the capsule sheathed in the ochrea; capsules usually light-colored, immersed or slightlyemergent, 1.5 mm. or less long, oblong to oblong-ovoid, abruptly narrowed to the seta, when dry 8-ribbed and contracted below the mouth; calyptra strongly plicate, naked or usually with a few very short hairs near the apex; exothecial cells differentiated; stomata immersed, the guard cells sometimes nearly covered by the surrounding cells, sometimes nearly all visible, both forms on one capsule; annulus present; peristome double, the 16 teeth usually united in pairs, finely papillose, refiexed when dry, rarely perforate above, the segments 8, linear, shorter than the teeth of 2 rows of cells at the base, easily broken; spores maturing in spring.
Type locality: Europe.
Distribution : On the bark of trees ; southeastern Canada and the eastern United States, south to Tennessee, west to Idaho and Utah; Europe; Canary Islands; Asia.