36. Orthotrichum rupestre Schleicher ex Schwagrichen, Sp. Musc. Frond. Suppl. 1(2): 27, plate 53 [top]. 1816.
Dorcadion rupestre (Schleicher ex Schwagrichen) Lindberg; Orthotrichum bullatum Müller Hal.; O. californicum Venturi; O. douglasii Duby; O. macfaddenae R. S. Williams; O. rupestre var. globosum (Lesquereux) Grout; O. rupestre var. macfaddenae (R. S. Williams) Grout; O. texanum Sullivant & Lesquereux; O. texanum var. globosum Lesquereux
Plants (1-)3-12.5 cm, . Stem leaves stiff, erect-appressed when dry, narrowly lanceolate to ovate-lanceolate, 2-4.5 mm; margins recurved to narrowly revolute to near apex, entire; apex sharply to slenderly acute; basal laminal cells elongate to rectangular, walls thick, ± nodose; distal cells 6-13 µm, 1-stratose, papillae 1 or 2 per cell, conic and small, or 2-fid and low. Specialized asexual reproduction absent. Sexual condition gonioautoicous. Seta to 1.8 mm. Capsule immersed, emergent, or slightly exserted, usually 1/3 emergent, globose ovate, ovate-oblong, or short-oblong, 1.3-1.8 mm, slightly or distinctly 8-ribbed 1/2 -2/3 length; stomata superficial; peristome single, rarely double; prostome large, conspicuous, or rudimentary; exostome teeth 16, erect or sometimes spreading-recurved when old, smooth, scattered-papillose, or coarsely papillose-granulate; endostome segments absent, or rarely 8, rudimentary, of 1 row of cells, smooth or roughened. Calyptra oblong, smooth, hairy or rarely naked, hairs finely papillose. Spores 13-21 µm.
Non-calcareous boulders and cliff faces in mesic areas of pine, spruce-fir, or aspen forests, base of trees, subalpine shade; low to high elevations (100-3000 m); Greenland; Alta., B.C., N.W.T., Nunavut, Ont., Yukon; Alaska, Ariz., Calif., Colo., Idaho, Mont., Nev., N.Mex., Oreg., S.Dak., Utah, Wash., Wyo.; South America; Europe; e Asia (Japan); n, e Africa; Atlantic Islands (Canary Islands); Pacific Islands (New Zealand); Australia.
In typical form, Orthotrichum rupestre is characterized as much-branched plants in loose tufts with lanceolate leaves, apex narrowly and bluntly acute, basal cells elongate, thick-walled, and nodose, yellowish in older leaves, capsule oblong, emergent, 8-ribbed to mid capsule when old and dry, smooth or slightly 8-ribbed when mature, exostome of 16 erect teeth, coarsely papillose, and calyptra with abundant, spinulose, papillose hairs, some of which extend over the beak.