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Montana Field Guides

Western Torncap Moss - Bucklandiella occidentalis
Other Names:  A Torncap Moss, Racomitrium occidentale

Status Under Review
Native Species

Global Rank: G4G5
State Rank: SNR

Agency Status
MNPS Threat Rank:

External Links

General Description
Plants: Growing in open, upright clumps or turfs, olivaceous above, brown below. Stems upright, spreading to ca 45 degrees, or creeping, 2-4 cm, sometimes reaching 8 cm, few-branched; central strand not present (FNA 2007).

Leaves: Upright and flat against the stem when dry, spreading to ca 45 degrees when wet, 2.2-3.8 mm in length, 0.5-0.8 mm in width, a little bowed to straight; margins undulate, curved back and downward up to 3/4 the leaf length on both sides; costa reaching the apex, the dorsal surface strongly rounded and with a dorsal, slightly off-center, longitudinal channel interrupting the convexity; hair-pointed, the awns 0.3-0.8 mm in length, finely and sharply toothed, not decurrent, round in X-section (FNA 2007).

Leaf Cells: Costa in X-section with the boundary outline noticeably asymmetric, from 3-5 cell-layers thick proximally, transitioning to 2-3 layers above, with 2-5 dorsal cells proximally, transitioning to 2-3 above; margins of 2 cell layers above in 1 or 2 (occasionally more) rows, sometimes with patches having 3-4 cell layers; laminal cells 1-layered with lengths of 2-layers here and there, smooth; middle and upper cells square to oblong, frequently becoming wider than long at the leaf edges; basal laminal cells long and narrow, wavy, minutely knobbed, and with spiraled thickenings near the attachment; alar cells only a little modified (FNA 2007).

Diagnostic Characteristics
The asymmetric costa with its winged appearance in X-section is unique in the genus (FNA 2007).

Range Comments
Endemic to North America. BC s to CA (FNA 2007). Known in Montana from Flathead County (Elliott 2016).

Dry to somewhat wet stones and bluffs; acidophile. Elevation: 0-5250 feet (FNA 2007).

Reproductive Characteristics
Seta 1-3 in a perichaetium, twisted clockwise above, 4-7 mm in length, somewhat ochre. Capsule 1-3 mm in length, a little creased when dry, shiny to dull brown; beak of operculum sometimes tilted; peristome dentitions papillose, lance-shaped, perforated or occasionally ruptured above into 2 lobes, brown (FNA 2007).

  • 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.
  • 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.
    • Lawton, E. 1971. Moss Flora of the Pacific Northwest. Hattori Botanical Laboratory. Japan: Yamabuki-cho, Shinjuku-ku, Tokyo. 362 pages plus appendices.
    • Malcolm, B., N. Malcolm, J. Shevock, and D. Norris. 2009. California Mosses. Nelson, New Zealand: Micro-Optics Press. 430 pp.
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Western Torncap Moss — Bucklandiella occidentalis.  Montana Field Guide.  .  Retrieved on , from