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A Boat Moss - Hygrohypnum molle
Other Names:  A Hygrohypnum Moss

Native Species

Global Rank: G4G5
State Rank: SNR

Agency Status
MNPS Threat Rank:

External Links

General Description
Plants: Pleurocarpous, growing in mats (Lawton 1971), soft (FNA 2014) or seldom rigid, slightly glossy (Crum and Anderson et al. 1981), green or olivaceous (FNA 2014), turning brown with age (Lawton 1971). Stems typically 20-30 mm, seldom (Crum and Anderson et al. 1981) reaching 100 mm, freely branching, with leaves intact along the lower part of the stem, possessing a central strand; hyalodermis and paraphyllia lacking (FNA 2014).

Leaves: Overlapping lightly, straight (FNA 2014), never curved in sickle-like fashion (Lawton 1971), although tip twisted in juvenile branch leaves when dry, otherwise similar dry or damp (FNA 2014), the upper part of the leaf spreading a little to broadly (Crum and Anderson et al. 1981), slightly to very concave, 0.8-2 mm in length, 0.6-1.3 mm in width, not pleated, widely egg-shaped, seldom nearly circular, narrowing slowly to an acute, dull apex (FNA 2014); the base extending a little down the stem (Crum and Anderson et al. 1981); leaf edges flat (FNA 2014) or a little bit curved back and downward proximally (Lawton 1971), smooth, a little wavy to finely-toothed above, particularly in the apex; costa typically paired with one arm extending halfway up the leaf or slightly further (FNA 2014).

Leaf Cells: Apical and medial cells very slender and bending or wavy to somewhat diamond-shaped; cells along margin seldom attaining 60 micrometers, not forming a border; alar cells short and oblong to square or oddly shaped, the alar area barely or not distinct from adjacent regions (FNA 2014).

Range Comments
North American Range

AK, BC to CA, CO (FNA 2014). Known in Montana from Cascade, Fergus, Flathead, Glacier, and Park Counties (Elliott and Pipp 2016).

Observations in Montana Natural Heritage Program Database
Number of Observations: 4

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Wet acidic stones in or close to mountain watercourses and seepy places (Elliott and Pipp 2016). Elevations ranging from 1970 to 10,830 feet (FNA 2014).

Reproductive Characteristics
Autoicous. Exterior perichaetial leaves spreading about 90 degrees , the costa absent; interior perichaetial leaves sometimes reaching 4 mm in length, strongly pleated, the costa weak (Lawton 1971), the leaf edges edges flat and toothed, the cells of the leaf tip papillose from overlapping cell ends. Seta 6-15 mm tall, russet to deep purplish-red or somewhat orange (FNA 2014). Capsule bowed, the theca sometimes reaching 2.3 mm in length, contracted below the opening when dry (Lawton 1971); exostome teeth brown (Crum and Anderson et al. 1981); endostome cilia scarcely developed (Lawton 1971).

  • 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.
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Citation for data on this website:
A Boat Moss — Hygrohypnum molle.  Montana Field Guide.  .  Retrieved on , from