A Haircap Moss - Pogonatum urnigerum
MNPS Threat Rank
Plants: Acrocarpous (Vitt 1988), growing in open clumps of upright shoots, sometimes sprinkled amongst other moss species, green, sometimes with a bluish bloom, in time turning brown. Stems 20-50 mm in height, regularly branching from just beneath terminal reproductive organs, often tree-like (FNA 2007), possessing a central strand (Lawton 1971).
Leaves: Upright, pressed near to the stem, and a little curved up and inward when dry, spreading broadly with the ends curved back and down when damp, dense and overlapping in the upper part of stems and branches, 2.5-6 mm in length, the sheathing base transparent and smooth along the edges and steadily tapering to or suddenly constricted at the limb (blade), the joint between sheath and limb distinct, the limb lance-shaped, widely to very slenderly so, weakly cupped, dentate from near the hinge to the leaf tip or nearly smooth; costa reaching or barely surpassing the apex, sometimes with a few teeth dorsally near the tip; lamellae green, covering most of the costa and lamina (FNA 2007).
Leaf Cells: Sheath-limb hinge consisting of thick-walled cells that reach up the limb margin slightly; lamellae 30-46, 4-7 cells in height, smooth along the top margin in side view, the uppermost lamellar cells large and heavily covered with papillae, in X-section wider than tall, the lumen somewhat pentagonal with the corners rounded; sheath cells short and quadrangular, becoming nearly isodiametric closer to the hinge; dorsal-facing cells nearly isodiametric with thick walls (FNA 2007)
Polytrichastrum alpinum, with its similar gametophyte, lacks the bluish bloom seen in P. urnigerum (Crum & Anderson et al., 1981).
North American Range
AK to NS and NL (except MB), WA and OR to MT, also CO, WI, VT and NH, TN (FNA 2007). Known in Montana from Flathead, Glacier, Lake, Lincoln, Mineral, and Stillwater Counties (Elliott & Pipp, 2016).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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(Observations spanning multiple months or years are excluded from time charts)
Disturbed, coarsely-textured soil along streams or road margins, fissures of bluffs or stones, areas of lingering snow. From medium elevations (FNA 2007) ranging to about 6560 feet (Lawton 1971).
Dioicous. Perigonium cup-like (Lawton 1971). Seta smooth, usually solitary in a perichaetium, 10-40 mm in height. Capsule upright or tilted, pale brown to russet, in time turning very dark; 2-3 mm in length; peristome with 32 russet teeth with transparent edges (FNA 2007). Calyptra draping like a hood (Lawton 1971), covered with thickly matted hairs, shielding most or all of the capsule (FNA 2007).
- 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.
- 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.
- Lawton, E. 1971. Moss Flora of the Pacific Northwest. Hattori Botanical Laboratory. Japan: Yamabuki-cho, Shinjuku-ku, Tokyo. 362 pages plus appendices.
- Vitt, D. J. Marsh, and R. Bovey. 1988. Mosses, Lichens & Ferns of Northwest North America. Seattle, WA: University of Washington Press. 296 p.
- Additional ReferencesLegend: View Online Publication
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- 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.
- Smith, A.J.E. 1980. The Moss Flora of Britain and Ireland. Cambridge University Press, Cambridge. 705 pp.