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River Conecap Moss - Leptodictyum riparium
Other Names:  Amblystegium riparium

Native Species

Global Rank: G5
State Rank: SNR

Agency Status
MNPS Threat Rank:

External Links

General Description
Plants: Pleurocarpous, growing in uncrowded, rambling mats (FNA 2014), occasionally floating (Lawton 1971), sometimes glossy when dry (Crum and Anderson et al. 1918), pale green to ochre. Stems 6-20 cm in length, freely branched (FNA 2014), the branches typically short and creeping (Crum and Anderson et al. 1981), possessing a weak central strand; paraphyllia lacking; rhizoids borne on the stem or dorsal costa at the attachment, nonpapillose (FNA 2014).

Leaves: A little bent and twisted when dry, upright to spreading widely, not pointing toward one side of the stem, sometimes seeming 2-ranked, frequently connected to the stem somewhat diagonally, not pleated, 2.5-6 mm in length (FNA 2014), 0.5-1.2 mm in width (Lawton 1971), somewhat rectangular to lance-shaped, narrowing to a short, wide acumen, slowly tapering to form a long acumen, or somewhere inbetween; base not extending down the stem; margins borderless, flat, smooth; costa solitary, extending over half to 75% of the leaf length. Stem and branch leaves similar (FNA 2014).

Leaf Cells: Distal cells diamond-shaped and short to very slender, to 15:1 (Crum and Anderson et al. 1981); medial laminal cells very slender; marginal cells 1 cell-layer thick (FNA 2014), the lower marginal cells somewhat oblong and from short to long (Crum and Anderson et al, 1981); alar cells oblong, inflated with fine-walls, differing from adjacent cells, the transition gradual (FNA 2014).

Diagnostic Characteristics
The variability of this species is considerable, and has given rise to other species, forms, and varieties (Crum and Anderson et al. 1981).

Range Comments
North American Range

Canada: Occurring in all territories and provinces: USA: AK and almost all continental states; Mexico (FNA 2014). Known in Montana from Flathead, Glacier, Granite, Lake, Meagher, Missoula, Lake, and Powder River Counties (Elliott and Pipp 2016).

Observations in Montana Natural Heritage Program Database
Number of Observations: 10

(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 places (Lawton 1971) on rotting wood, humus, the bottoms of trees, leaf mold, twig/branch litter in swamps, occasionally underwater where water is running or still (but not saline), in limestone springs (Crum and Anderson et al. 1981). Occurring from low elevations to about 9840 feet (Lawton 1971).

Reproductive Characteristics
Autoicous. Seta solitary, pale- to deep-brown. Capsule bowed (FNA 2014), nodding, and constricted below the opening when dry, or seldom short and wide without the constriction (Lawton 1971), 2.2-2.5 mm in length, russet or somewhat brown; exostome teeth with a border; endostome processes thread-like and transparent; cilia knobby. Calyptra hairless (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.
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Citation for data on this website:
River Conecap Moss — Leptodictyum riparium.  Montana Field Guide.  .  Retrieved on , from