Orthotrichum pycnophyllum Schimp.

  • Authority

    Sharp, Aaron J., et al. 1994. The Moss Flora of Mexico. Part Two: Orthotrichales to Polytrichales. Mem. New York Bot. Gard. 69 (2)

  • Family

    Orthotrichaceae

  • Scientific Name

    Orthotrichum pycnophyllum Schimp.

  • Description

    Species Description - Plants 0.8-5 cm high, slender to moderately robust, in loose, dull-green tufts. Stems simple or branched, stiff or flexuose. Leaves loosely erect-spreading when dry, spreading to spreading-recurved when moist, 2.5-4 mm long, lanceolate, gradually acuminate to long-acuminate-cuspidate, often irregularly channeled and undulate at the apex; margins revolute below, becoming plane somewhere in the upper 1/4, often wavy and slightly notched near the apex; costa ending near the apex; upper cells 7-13 µm wide, irregularly rounded, with 1-2 conic papillae per cell; basal cells elongate, nodose, becoming short-rectangular toward the margins. Gonioautoicous. Setae 1—2(—3) mm long; capsules 1.5-2 mm long, immersed to shortly exserted, generally 1/2-3/4 emergent, oblong-ovoid to cylindric, smooth to moderately 8-ribbed, gradually contracted to the seta; exothecial cells ± differentiated; stomata superficial, at or just below the middle of the urn; exostome teeth 16, sometimes irregularly joined in 8 pairs, obscurely and densely papillose, recurved; endostome segments 16, or sometimes 8, stout, 2 cells wide, incurved to erect, sometimes erose, coarsely papillose. Spores 17-32(-35) µm, coarsely papillose. Calyptrae conic-oblong, plicate, smooth, moderately hairy, with a dark beak.

  • Discussion

    Fig. 456

    O. pycnophyllumSchimp. exC. Müll., Syn. Muse. Frond. 1:709.1849.

    O. recurvans Schimp. ex C. Miill., Syn. Muse. Frond. 1: 709. 1849.

    O. lozanoi Card., Rev. Bryol. 36: 107. 1909.

    O. lozanoi var. lutescens Card., Rev. Bryol. 36: 107. 1909.

    O. pycnophyllum var. lutescens (Card.) Grout, N. Amer. Fl. 15A: 10. 1946.

    This is the most common Orthotrichum in Mexico. It is one of the larger species, quite variable but usually identifiable by leaves loosely erect-spreading when dry, with margins mostly recurved; basal cells elongate and nodose; capsules smooth to moderately 8-ribbed with superficial stomata- setae usually less than 2 mm long; capsules usually emergent; and peristome well-developed with 16 recurved exostome teeth and 16 stout, incurved endostome segments.

    Orthotrichum hortoniae has longer, flexuose setae and more regular leaf tips. Both (). aequatoreum and O. sharpii are much smaller, with immersed stomata.

  • Distribution

    On the trunks and branches of trees in moist to xeric forests and shrublands, seemingly most common in Pinus-, Quercus-, and Abies-dominated forests, often associated with Orthotrichum hortoniae, O. aequatoreum, and O. sharpii in mesic sites, also found on shrubs at higher elevations; Chiapas, Chihuahua, Coahuila, Distrito Federal, Durango, Hidalgo, Michoacan, Nuevo Leon, Oaxaca, Puebla, San Luis Potosi, Tamaulipas, Tlaxcala, Veracruz.—Mexico; Guatemala; western Texas, New Mexico, and Arizona.

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