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Montana Field Guides

A Plagiobryum Moss - Plagiobryum demissum

Status Under Review
Native Species

Global Rank: G3G5
State Rank: SU

Agency Status
MNPS Threat Rank:

External Links

General Description
Plants: Acrocarpous, growing in crowded turfs or cushions of erect shoots, red to russet-colored (FNA 2014) or green with red tones (Lawton 1971). Stems 3-12 mm in height; new, sterile branches forming at the base of matured sex organs (innovations), short, possessing a central strand (FNA 2014).

Leaves of Innovations: Upright to spreading about 45 degrees when dry, spreading more when moist, lance-shaped with ovate tendencies, sometimes egg-shaped (fertile branches with leaves plainly lance-shaped), larger near the top of the stem, flat or slightly cupped (FNA 2014), 1-2.5 mm in length (Lawton 1971), narrowing to an acute leaf tip; leaf tip curved back and downward somewhat; margins smooth (FNA 2014), curved back and down in the distal leaves; costa red (Lawton 1971), disappearing in the apex to extending beyond it (FNA 2014).

Leaf Cells: Lower laminal cells 3-5:1; medial laminal cells rectangular to diamond-shaped, or 6-sided and slender; margins unbordered and 1 cell-layer thick; cells of the alar region similar to adjacent cells; costa in X-section with ventral cells in 1 or 2 rows and a well-developed dorsal stereid band, lacking guide cells (FNA 2014).

Fruit ripens the last part of summer into autumn (FNA 2014).

Diagnostic Characteristics
Infertile plants are almost impossible to tell from small Bryum species that have reddish coloration. In fertile plants, the drooping capsule bulging near its distal end combined with the reddish-colored gametophyte distinguishes this species (FNA 2014).

Range Comments
North American Range

AK to NU, BC and AB, CO and NL (FNA 2014). Known in Montana from Glacier National Park (Elliott & Pipp, 2016).

Soil and stone of mountainous areas (Lawton 1971), wet, basic stone of bluffs. Elevation: 0-1780 feet (FNA 2014).

Reproductive Characteristics
Dioicous. Perigonia gemmiform. Seta swan-necked (FNA 2014), 5-10 mm in height, ochre (Lawton 1971). Capsule drooping, swollen near the distal end (gibbous), 2-5 mm in length, the neck about 1/2 to slightly longer than the length of the theca; endostome segments often more than two times the length of the exostome sections (FNA 2014), frequently joined together near the top (Lawton 1971), slender, the perforations narrow, the cilia scarcely developed (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.
    • 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
    Do you know of a citation we're missing?
    • 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.
    • Smith, A.J.E. 1980. The Moss Flora of Britain and Ireland. Cambridge University Press, Cambridge. 705 pp.
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Citation for data on this website:
A Plagiobryum Moss — Plagiobryum demissum.  Montana Field Guide.  .  Retrieved on , from