Orthotrichum Moss

Orthotrichum laevigatum J. E. Zett. Bull
Soc. Bot. Fr. 9:287. 1862.
Orthotrichum Douglasii Duby, Mem. Soc. Phys. Hist. Nat. Geneve 19: 293. 1868. (Type seen.) Orthotrichum rhabdophorum Venturi; Roll, Bot. Centr. 44: 418. 1890.
Plants dark brownish-green almost to the tips, 5-25 mm. high, more or less branched above, growing rather loose tufts; leaves erect-open when moist, broadly lanceolate to ovatelanceolate, narrowly obtuse, 2-4 mm. long, when young sometimes acute, the margins revolute nearly to the apex; costa stout, mostly dorsal, extending nearly or quite to the apex; upper leaf -cells dense, irregular, rounded, nearly isodiametric, incrassate, papillose (the papillae * simple, bifid, or trifid, strongly salient), 10-12 p in diameter, rarely in two layers above, the basal cells oblong to rectangular, translucent but often somewhat colored, their walls becoming thickened and often somewhat nodose when old, 9-15 fi wide, 2-4 times as long near the costa, the marginal cells shorter, subquadrate; autoicous; antheridial buds axillary; seta reaching 2-4 mm. long; capsules exserted, about one-half to three-fourths the length of the seta, ovoid to oblong-ovoid, cylindric when dry and empty, wrinkled when very old, otherwise smooth or nearly so except at the short or rather long neck ; calyptra hairy, reaching to the mouth of the capsule ; stomata superficial, few, in the lower half of the capsule ; bordering cells shorter but not
* On young leaves the papillae seem very large and prominent, but on most of the older leaves they seem lower and rounded ; in any case the papillae vary greatly on leaves of the same plant. radiating; annulus persistent, with 4-6 rows of small thickwalled cells below it gradually merging into the slightly differentiated (i.e. nearly uniform all around), oblong to rectangular exothecial cells; operculum short-rostrate; peristome-teeth erect * or inclined inward, 16, united in pairs at first, sometimes perforate above, the articulations strongly marked, papillose, the segments varying from well developed to almost lacking; spores 10-15 m in diameter, lightly papillose, maturing in early spring.
Type locality: Near Rodsheim, Norway.
Distribution: On rocks; British Columbia to California and Nevada; Idaho; Wyoming; Utah.