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Pulvinate Dry Rock Moss - Grimmia pulvinata
Other Names:  Pulvinate Black Rock Moss

Native Species

Global Rank: G4G5
State Rank: SNR

Agency Status
MNPS Threat Rank:

External Links

General Description
Plants: Acrocarpous (Vitt 1988). Grayish green, dull yellow-brown or dark green (Crum 1981), growing in hoary rounded cushions. Stems 1-3 cm, possessing a central strand (FNA 2007).

Leaves: Upright when wet, wavy or bent when dry, lanceolate (FNA 2007) to widely oblong-lanceolate, keeled (Crum 1981), 1-1.7 mm in length, 0.3-0.6 mm in width; margins both usually recurved from base to apex, contracting suddenly to form awn (FNA 2007), smooth; awn hyaline, strongly keeled, varying from short to long, smooth to toothed; costa protruding on surface away from stem, extending into the base of the awn (Crum 1981).

Leaf Cells: Basal laminal cells near costa with thin walls, nearly square to short-rectangular; basal marginal laminal cells similarly shaped with thin to thick walls; medial laminal cells rounded to squarish, slightly wavy with thin walls; distal laminal cells 1-layered, margins 2-layered (FNA 2007).

Diagnostic Characteristics
Pioneer species with nearly worldwide distribution. Easy to recognize rounded cushions with numerous capsules. G. pulvinata’s short-rectangular thin-walled basal cells and rounded small mid leaf cells distinguish it from G. trichophylla (FNA 2007).

Range Comments
Canada: BC, ON; USA: AZ, CA, CO, ID, IN, IA, KS, MD, MI, MS, MO, MT, NV, NM, OK, OR, SD, TX, UT, WA, WY; Mexico; South America (Argentina, Chile, Uruguay); Eurasia; Africa; Pacific Islands (New Zealand); Australia (FNA 2007). In Montana, known from Cascade, Lake, Mineral, Ravalli, and Sanders Counties (Elliott 2016).

Acidic to basic rocks (including old concrete occasionally), even tree trunks. Low to high elevations. Sea level to 9800 feet (FNA 2007).

Reproductive Characteristics
Autoicous. Seta erect and twisted when dry, bow-shaped when wet, 3-6 mm (FNA 2007), longer than the capsules. Capsules usually present, exserted, horizontal to drooping when moist; the urn brownish and ribbed when dry (Flowers 1973).

Gemmae absent (FNA 2007).

  • Literature Cited AboveLegend:   View Online Publication
    • Crum, H.A. and L.E. Anderson. 1981. Mosses of Eastern North America. 2 volumes. Columbia University Press, New York. 1328 pp.
    • Elliott, J.C. and A.K. Pipp. 2018. A Checklist of Montana Mosses (1880-2018). December 20th. Montana Natural Heritage Program, Helena, Montana. 73 pp.
    • Flora of North America Editorial Committee, eds. 2007. Flora of North America North of Mexico. Volume 27. Bryophytes: Mosses, Part 1. Oxford University Press, Inc., NY. xxi + 713 pp.
    • Flowers, S. 1973. Mosses: Utah and the West. Brigham Young University, Provo, Utah. 567 p.
    • Vitt, D. J. Marsh, and R. Bovey. 1988. Mosses, Lichens & Ferns of Northwest North America. Seattle, WA: University of Washington Press. 296 p.
  • Additional ReferencesLegend:   View Online Publication
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    • Lawton, E. 1971. Keys for the Identification of the Mosses on the Pacific Northwest. Reprinted from 'Moss Flora of the Pacific Northwest'. Published as Supplement No. 2 of the Journal of the Hattori Botanical Laboratory. Nichinan, Miyazaki, Japan. 66 pp.
    • Lawton, E. 1971. Moss Flora of the Pacific Northwest. Hattori Botanical Laboratory. Japan: Yamabuki-cho, Shinjuku-ku, Tokyo. 362 pages plus appendices.
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Citation for data on this website:
Pulvinate Dry Rock Moss — Grimmia pulvinata.  Montana Field Guide.  .  Retrieved on , from