Tortula obtusissima (Müll.Hal.) Mitt.

  • Authority

    Sharp, Aaron J., et al. 1994. The Moss Flora of Mexico. Part One: Sphagnales to Bryales. Mem. New York Bot. Gard. 69 (1): 1-452.

  • Family

    Pottiaceae

  • Scientific Name

    Tortula obtusissima (Müll.Hal.) Mitt.

  • Description

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    Species Description - Plants moderately large, (5-) 10-20 mm high, in dense, yellow-brown, often bluish-green and glaucous, hoary tufts. Leaves clasping at base, infolded, and twisted around the stem when dry, wide-spreading to squarrose when moist, 3-4 mm long, 1-1.5 mm wide, Ungulate to spatulate, keeled, emargin emarginate to retuse (or occasionally truncate or acute); margins revolute in the lower 3/4-7/8, entire, often laxly undulate; costa strong, yellow or brown, often minutely papillose at back (but not serrate because of projecting cell ends), excurrent into a toothed, hyahne hair point (often brown at base) usually longer than the leaf; upper cells 15-23 µm, quadrate to polygonal, thin-walled, pellucid, bulging and bearing 4-7 papillae per cell; basal cells abruptly differentiated, rectangular, 70-90(-100) x 22-40 µm, often with yellow walls, narrowly rectangular at the margins. Autoicous (but perigonia often lacking), apparently sometimes dioicous. Setae 10-15 mm long, red-brown; capsules 3-4.5 mm long, straight or slightly curved, with an abrupt neck, yellowish or reddishbrown; operculum 1.5-2 mm long, reddish-brown; peristome ca. 1.5 mm long, the upper divisions yellow or red, twisted ca. 2 turns, the basal membrane white, 1/3 the total length. Spores 9-16 µm, papillose. Calyptrae 4-5 mm long, yellow.

  • Discussion

    Fig. 257

    T. obtusissima (C. Mull.) Mitt, J. Linn. Soc, Bot. 12: 174. 1869.

    Barbula obtusissima C. Miill., Syn. Muse. Frond. 1: 640. 1849.

    Tortula connectens Card., Rev. Bryol. 36: 87. 1909.

    T. obtusissima var. connectens (Card.) Ther., Smithsonian Misc. Collect. 85(4): 25. 1931.

    Tortula obtusissima, a species of an interesting Mexican-Andean disjunction, has been m u c h confused with T. ruralis, and it seems to belong to that world-wide species complex (see discussion under T. ruralis, below). The large, pellucid leaf cells (about 15-23 µm) contrast with those of T. ruralis (about 8-12 µm), and the back of the costa lacks serrations caused by projecting cell ends. These distinctions hold up under common garden conditions (Mishler, 1985a). With its large cells and tendency toward monoicous sexuality, T. obtusissima m a y prove to be polyploid.

  • Distribution

    Occasional on dry or moist soil and rock, rarely on the bases of trees; Baja California, Chihuahua, Coahuila, Distrito Federal, Durango, Hidalgo, Mexico, Morelos, Nuevo Leon, Oaxaca, Puebla, Queretaro, San Luis Potosi, Tamaulipas, Tlaxcala, Veracruz, Zacatecas.—Mexico; southwestern United States; Peru and Bolivia.

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