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Montana Field Guides

Bird's-claw Beard Moss - Barbula unguiculata
Other Names:  Prickly Beard Moss

Native Species

Global Rank: G5
State Rank: SNR

Agency Status
MNPS Threat Rank:

External Links

General Description
Plants: Growing in open to compact tufts, green to deep green (Lawton 1971), brown or a little dark below (Flowers 1973). Stems 10-20 mm; possessing a central strand (FNA 2007).

Leaves: Imbricate or slightly spreading and frequently twisted and bent when dry, spreading when wet, a little concave and sheathing the stem slightly, from widely lance-shaped to long and strap-shaped, 1-2.5 mm in length, margins turned back and down in the lower half or so; apex just short of obtuse to rounded; costa extending beyond the apex to form an abrupt point, short to long, seldom lacking, the dorsal face sprinkled with papillae (FNA 2007).

Leaf Cells: Lamina 1-layered; upper laminal cells square (FNA 2007) and multi-papillose on both faces (Crum and Anderson et al. 1981); basal laminal cells rectangular, 3-5:1, broader than the distal cells; costa with hydroids present (FNA 2007), papillose on the dorsal surface (Crum and Anderson et al. 1981).

Capsules ripen mostly from winter into the first part of spring, and other times of the year infrequently (FNA 2007).

Diagnostic Characteristics
Characteristics of this species separating it from B. convoluta include its lack of specialized vegetative reproduction, margins recurved in the lower 1/2-2/3, an excurrent costa, and a russet-colored seta. B. convoluta (sometimes) produces large tubers, has typically flat margins, a costa usually subpercurrent, and a yellow seta (FNA 2007).

Range Comments
North American Range

Widespread throughout Canada and the USA, common in Eastern North America; present but rare in the Arctic, Mexico, and other tropical areas (FNA 2007). Known in Montana from Carter, Cascade, Choteau, Flathead, Madison, Park, Ravalli, and Roosevelt Counties (Elliott 2016).

Usually calcareous; soil and walls (Elliott 2016), in lawns and along roads. Elevation: 165-8860 feet (FNA 2007).

Reproductive Characteristics
Dioicous. Perichaetial leaves slightly larger than but otherwise similar to the vegetative leaves (Lawton 1971). Seta russet, 10-25 mm in length (FNA 2007). Capsule erect (Smith 1980), the urn 10-25 mm in length; peristome long and spiraled (FNA 2007), reddish-orange (Crum and Anderson et al. 1981). Specialized vegetative reproduction lacking (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). Updated 3 January, 2020. 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.
    • Lawton, E. 1971. Moss Flora of the Pacific Northwest. Hattori Botanical Laboratory. Japan: Yamabuki-cho, Shinjuku-ku, Tokyo. 362 pages plus appendices.
    • Smith, A.J.E. 1980. The Moss Flora of Britain and Ireland. Cambridge University Press, Cambridge. 705 pp.
    • 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.
    • 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:
Bird's-claw Beard Moss — Barbula unguiculata.  Montana Field Guide.  .  Retrieved on , from