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An Orthotrichum Moss - Orthotrichum pumilum

Native Species

Global Rank: G5
State Rank: SNR

Agency Status
MNPS Threat Rank:

External Links

General Description
Plants: Acrocarpous, growing in loose clumps of upright shoots (FNA 2014) or occasionally scattered, deep green (Lawton 1971). Stems sometimes reaching 5 mm in height (FNA 2014).

Leaves: Straight and lightly imbricate when dry, spreading, sometimes broadly, when damp, 1.8-2.8 mm in length, lance-shaped and sometimes with ovate tendencies, tapering to the narrowly acute (seldom more broadly-angled) and typically apiculate leaf tip (FNA 2014), the tip occasionally toothed (Crum and Anderson et al. 1981); leaf edges smooth, rolled back nearly to the leaf apex (FNA 2014); costa not reaching the leaf tip (Lawton 1971).

Leaf Cells: Upper laminal cells chlorophyllous (Crum and Anderson et al. 1981), somewhat round and isodiametric, smooth or with 1 or 2 small, cone-shaped papillae over each lumen; lower laminal cells oblong, transitioning to square at the leaf edge, the walls fine and without knobs (FNA 2014).

Range Comments
North American Range

Canada: AB to ON; USA: WA, CA, ID to AZ, MT, CO, NM, ND to TX, MN to MO, MI to WV and to the coastal states east of them, also AL, TN and SC (FNA 2014). Known in Montana from Cascade, Fallon, Flathead, Glacier, Powder River, and Ravalli Counties (Elliott and Pipp 2016).

Observations in Montana Natural Heritage Program Database
Number of Observations: 6

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Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Tree trunks and stone fissures (Lawton 1971). Occurring from lowlands to about 3280 feet in elevation (FNA 2014).

Reproductive Characteristics
Autoicous. Seta twisted, about 0.5 mm tall. Capsule about 1.5 mm in length, hidden amongst the perichaetial bracts to partially emerged (about 75%), with 8 prominent longitudinal ribs, occasionally contracted below the opening when dry; stomata sunken and sometimes partially obscured by adjacent cells; exostome of 8 teeth, seldom divided into 16, bending back and downward, with small papillae; endostome processes 8 (FNA 2014), smooth (Crum and Anderson et al. 1981), typically not as tall as the teeth, each of 1 or 2 cell rows (Lawton 1971). Calyptra cone-shaped, sheltering the full length of the capsule, with the smooth hairs sparse or seldom absent (FNA 2014).

Vegetative reproduction sometimes occurring from gemmae borne on leaves (FNA 2014).

  • 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). Updated 3 January, 2020. Montana Natural Heritage Program, Helena, Montana. 73 pp.
    • Flora of North America Editorial Committee, eds. 2014. Flora of North America North of Mexico. Volume 28. Bryophytes: Mosses, Part 2. Oxford University Press, Inc., NY. xxi + 702 pp.
    • Lawton, E. 1971. Moss Flora of the Pacific Northwest. Hattori Botanical Laboratory. Japan: Yamabuki-cho, Shinjuku-ku, Tokyo. 362 pages plus appendices.
  • 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.
    • Malcolm, B., N. Malcolm, J. Shevock, and D. Norris. 2009. California Mosses. Nelson, New Zealand: Micro-Optics Press. 430 pp.
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Citation for data on this website:
An Orthotrichum Moss — Orthotrichum pumilum.  Montana Field Guide.  .  Retrieved on , from