A Mat Moss - Brachythecium acutum
MNPS Threat Rank
Plants: Pleurocarpous (Vitt 1988). Growing in open to crowded mats, yellow to brown. Stems prostrate, in X-section round or sometimes somewhat flattened, to 7 cm in length; possessing a central strand. Branches also round or moderately flattened, to 8 mm in length (FNA 2014).
Leaves: Stem leaves upright to spreading somewhat, lightly imbricate to a little distantly spaced, widely to slenderly egg-shaped and deltoid, widest near the leaf base, 2-2.8 mm in length, ca 1 mm in width, not cupped, folded longitudinally or not; margins flat or sometimes curved back and under above, nearly smooth to regularly and extremely finely toothed; apex narrowing to a long, slender point or occasionally with a short, abrupt point; costa extending between half and 3/4 the leaf length, lacking an abaxial spine. Branch leaf edges frequently curved back and downward proximally, typically fewer-toothed than the stem leaves (FNA 2014).
Leaf Cells: Stem leaf laminal cells thin and elongate, with or without pores; basal cells arranged in several rows; alar cells just shy of square or a bit lengthened, little to moderately differentiated. Branch leaves with only a few alar cells (frequently concealed by the margins) or with basal cells not differentiated (FNA 2014).
North American Range
Canada: YT, NU, BC, SK to QC, NL; USA: AK, CA, ID and UT e to ND, SD, and NE, IA, MO, IL e to DE and NY, ME (FNA 2014). In Montana, known from Dawson, Flathead, Gallatin, Lake, Lewis and Clark, Madison, and Missoula Counties (Elliott 2016).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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Map Help and Descriptions
(Observations spanning multiple months or years are excluded from time charts)
Rotten wood and humus (Elliott 2016), wet soil, fens. Elevation: 0-3280 feet (FNA 2014).
Autoicous. Seta russet, 20-40 mm. Capsule russet, tilted to level, faintly bowed, 1.5-2 cm in length (FNA 2014).
- Literature Cited AboveLegend: View Online Publication
- 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.
- 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.