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A Dry Rock Moss - Grimmia trichophylla
Other Names:  A black Rock Moss

Native Species

Global Rank: G5?
State Rank: SNR

Agency Status
MNPS Threat Rank:

External Links

General Description
Plant: Dense to loose patches. Yellow-green to dark green. Stems 2.0-4.0 cm tall. Stem’s central strand present.

Leaf: Loosely appressed on stem. When dry, leaves slightly twisted. When moist, leaf and stem make less than a 25 degree angle (erectopatent). Lanceolate to oblong-lanceolate, 2.0-3.5 x 0.3-0.4 mm, tapers to an acute apex, and sharply keeled. Awn variable: short to long, smooth to denticulate, and conspicuously or not flattened at base; some leaves may not have awns. One or both margins recurved. Costa ends before apex, is firm, and projects on abaxial surface (strongly keeled).

Leaf Cells: Basal laminal cells near costa are long-rectangular (rarely short-rectangular), somewhat knobby (nodulose), and thick-walled. Basal laminal cells near margin are short- to long-rectangular and thick-walled transversely. Median laminal cells are quadrate to short-rectangular, somewhat sinuose, and thick-walled. X-S: distal laminal cells are 1-layered, but sometimes with 2-layered ridges. Costa X-S: distally angular (keeled) or smooth in outline.

Diagnostic Characteristics
Species can often be confused with G. muehlenbeckii, G. lisae, and G. austrofunalis. G. trichophylla’s thick-walled, long-rectangular basal cells and quadrate to short-rectangular medial laminal cells distinguish it from G. pulvinata (FNA 2007).

Range Comments
Central Mexico; western North America; South America; Europe; Asia; Africa; Australia and New Zealand (Sharp et al. 1994). Canada: BC; USA: AZ, CA, CO, ID, ME, MO, MT, NV, OK, OR, SD, UT, VT, WA, WY; Mexico; Eurasia; Pacific Islands (Hawaii); Australia (FNA 2007). In Montana, known from Flathead, Gallatin, Lake, Lincoln, Missoula, and Sanders Counties (Elliott 2016).

Dry, acidic rock. Low to high elevations (650 – 3,300 feet) in North America. Damp and shaded, or otherwise less favorable sites, may produce short awns and leaves.

Reproductive Characteristics
Dioicous. Seta is 2.0-4.0 mm tall, arcuate, and symmetrically attached to base of capsule. Capsules are occasionally found, exserted, yellow-green to straw-colored, oblong-ovoid.

Gemmae sometimes present as clusters in the upper leaf axils.

  • Literature Cited AboveLegend:   View Online Publication
    • Elliot, J.C., and A.K. Pipp. 2018. A Checklist of Montana Mosses (1880-2018). December 5. 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.
    • Sharp, A. J., H. A. Crum, and P. M. Eckel. 1994. The Moss Flora of Mexico. Memoirs of the New York Botanical Garden, Volume 69. Bronx, NY: New York Botanical Garden. 2 volumes, viii + 1113 pp.
  • 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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A Dry Rock Moss — Grimmia trichophylla.  Montana Field Guide.  .  Retrieved on , from