Polytrichum commune Hedw.

  • 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

    Polytrichaceae

  • Scientific Name

    Polytrichum commune Hedw.

  • Description

    Species Description - Medium-sized to robust plants, in tufts. Stems simple, 3-4(-25) cm tall, densely leafy above, bracteate below. Leaves erect-spreading with recurved tips when dry, wide-spreading to broadly recurved when moist; sheath oblong to elliptic, the margin entire, hyaline above; limb subulate, ending in a short, rough point, toothed at back near the tip, marginal portion of lamina erect, 6-7 cells wide, studded with reflexed, unicellular teeth; lamellae finely crenulate in profile, 6-8 cells high, with marginal cells in section retuse to bilobed, smooth, 16-22 µm wide; sheath cells elongate-rectangular to linear, 10-13 µm wide, 70-90 µm long. Dioicous. Perigonial leaves broad, forming a conspicuous rosette. Perichaetial leaves longer, with a greatly reduced limb, hyaline-margined. Setae stout, golden-brown, 7 cm long; capsules inclined to horizontal, cuboidal, sharply 4-angled, red-orange, glaucous when fresh; apophysis sharply delimited by a deep groove; exothecial cells bulging-mammillose, pitted; operculum umbonate, with a short beak; peristome teeth 64, single, with a vertical keel at back, pale; epiphragm delicate, with dependent mammilliform processes at the margin alternating with the teeth. Spores 5-8 µm, smooth, greenish. Calyptra hairy, covering the entire capsule.

  • Discussion

    Fig. 795

    P. commune [L.] Hedw., Sp. Muse. 88. 1801.

    In Africa the section Polytrichum is represented by a bewildering array of forms, but tropical America has few of the relatives of P. commune. Polytrichum ericoides Hampe, of Colombia, is distinguished by leaves with an obtuse, awnless apex and crowded marginal teeth; P. angustifolium Mitt., with toothed leaves but lamellae like those of P. juniperinum, occurs in Brazil.

  • Distribution

    Hidalgo and Oaxaca.—Mexico; North America; Eurasia; Australia and New Zealand.

    New Zealand Australia Oceania| Europe| Asia| North America| Mexico North America|