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A Ptychostomum Moss - Ptychostomum cernuum
Other Names:  Bryum uliginosum

Native Species

Global Rank: G3G5
State Rank: SNR

Agency Status
MNPS Threat Rank:

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General Description
Plants: Acrocarpous. Growing in large, loose to crowded patches (FNA 2014) or clumps (Lawton 1971) of upright shoots, green, occasionally with yellow tones. Stems 5-30 mm in height (FNA 2014), sometimes forked (Lawton 1971), with fertile branches that have leaves dense at the top of the stem (comose) (FNA 2014).

Leaves: Somewhat openly spaced (Crum & Anderson et al. 1981) to densely so, strongly twisted and curved to contracted when dry, upright to spreading somewhat when wet, green or sometimes with yellow tones, 1-4 mm in length, lance-shaped, tending toward egg-shaped, plane, steadily becoming larger with height on the stem, green at the base, the leaf tip acuminate; margins smooth to minutely toothed apically (Lawton 1971), rolled back and downward below, flat above, bordered; costa extending to the leaf tip or slightly beyond to form a robust awn (FNA 2014).

Leaf Cells: Border of 2-3 cell rows, parts of the proximal border 2-layered; lower laminal cells long and quadrangular, 3-5:1; medial and upper cells fine-walled, diamond-shaped to 6-sided, 3-4:1 (FNA 2014).

Fruit ripens in summer (FNA 2014).

Diagnostic Characteristics
Compared to the similar Bryum turbinatum, B. uliginosum is autoicous rather than dioicous, smaller, and with leaves more slenderly lance-shaped and somewhat ovate. The leaves of B. turbinatum are wide and more ovate (FNA 2014).

B. uliginosum is closely related to Bryum pallens, but B. uliginosum is autoicous rather than dioicous (FNA 2014).

Range Comments
North American Range

Canada: YT to NL; USA: ND to NE, e to NY and PA, also CO and NM (FNA 2014). Known in Montana from Cascade, Flathead, Glacier, Lincoln, and Meagher Counties (Elliott 2016).

Wet soil or humus in stone fissures, near springs (Crum & Anderson et al. 1981), bogs (Lawton 1971), stream banks. Elevation: 0-9840 feet (FNA 2014).

Reproductive Characteristics
Autoicous. Seta 20-40 mm tall (FNA 2014), sometimes up to 70 mm (Crum & Anderson et al. 1981), ochre to brown. Capsule mostly 4-6 mm in length, pear- to club-shaped, the shape varying greatly (FNA 2014) but generally long and slim (Crum & Anderson et al. 1981), level to drooping nearly 45 degrees (subcernuous); capsule neck narrowing, nearly the length of the remaining capsule (Lawton 1971), slender; peristome not fully developed; exostome dentitions mostly entirely yellow, seldom transparent above, without pores near the basal mid-line; endostome divisions with egg-shaped openings; cilia not present or scarcely developed (FNA 2014).

No specialized vegetative reproduction present (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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    • Flowers, S. 1973. Mosses: Utah and the West. Brigham Young University, Provo, Utah. 567 p.
    • 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.
    • Vitt, D. J. Marsh, and R. Bovey. 1988. Mosses, Lichens & Ferns of Northwest North America. Seattle, WA: University of Washington Press. 296 p.
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Citation for data on this website:
A Ptychostomum Moss — Ptychostomum cernuum.  Montana Field Guide.  .  Retrieved on , from