Common Name: Hummock haircap, Slender haircap, Narrow-leaved haircap
Scientific Name: Polytrichum strictum
Recent synonyms: Polytrichum juniperinum var. affine
Technical Description: Plants erect, 1-10 (20) cm tall, mostly unbranched, stems between the leaves densely covered with whitish to light brown wooly tomentum. Leaves (2) 4-6 (8) mm long, awl-shaped, green, bluish-green to reddish brown with reddish-brown tips, stiffly appressed when dry, erect-spreading when moist, the upper (adaxial) side of the leaves covered with parallel ranks of tissue (lamellae) 5-8 cells tall extending from leaf base to apex. Leaf margins entire, membranous, transparent (hyaline), folded inward and covering the lamellae. Setae brown, 2-4 (6) cm long. Capsules brown, 2-3 (5) mm long, square in cross-section. Peristome membranous like the head of a drum, not composed of teeth. Distinctive characters: Polytrichum strictum is the only Polytrichum growing on Sphagnum hummocks that has overlapping leaf margins that hide the lamellae. The overlapping leaf margins can be seen with a hand lens as a fine line running down the center of the adaxial leaf surface. Similar species: Polytrichum juniperinum looks very similar to P. strictum but (1) lacks the whitish wooly tomentum on the stem and (2) grows only on dry, exposed mineral soil or sand. Polytrichum commune sometimes grows on Sphagnum hummocks in the Pacific Northwest but its leaves are toothed and do not have infolded margins, so the lamellae are plainly visible. Other descriptions and illustrations: Frye 1910: 325; Frye 1937: 127; Lawton 1971: 42; Crum and Anderson 1981: 1272; Ireland 1982: 683; Vitt et al. 1988: 57; Christy and Wagner 1996: VII-52; Merrill 2007: 139.
Life History: Details for Polytrichum strictum are not documented. The protonema is inconspicuous, forming buds and shoots in the usual fashion of moss growth and development.
Range, Distribution, and Abundance: Circumboreal and bipolar. In the Pacific Northwest, known from British Columbia, Alberta, Montana, Washington, Oregon, and California (Norris and Shevock 2004).
National Forests: none documented; suspected on forests in the region with suitable bog or fen habitat. Documented from Olympic National Park (Hutten et al. 2005). BLM Districts: none documented; suspected on the Salem and Coos Bay districts.
Rare in Oregon and Washington but a common component of boreal bogs and fens. Because Polytrichum strictum is conspicuous, it is unlikely that it has been overlooked in bogs and fens in the Pacific Northwest if these habitats have been well inventoried bryologically.
Habitat Associations: Plants scattered individually or forming loose turfs on organic soils, particularly on top of Sphagnum hummocks, in coastal and montane bogs and fens. Tops of hummocks receive the most intense insolation and are the most nutrient-poor sites in these habitats. Associated species include Vaccinium oxycoccos, Ledum glandulosum, Carex, the mosses Sphagnum, Pohlia sphagnicola, and Aulacomnium palustre. Associated vascular plants may be stunted because of poor nutrient status.
Threats: Over the last century, fen habitats have been impacted by grazing, water diversion, water impoundment, drainage projects, road construction, commercial harvest of peat and sphagnum moss, and succession in the absence of fire. Changes in water regime, nutrient inputs, and succession lead to the disappearance of fen communities and species. Federal and state regulations prohibit building new roads in wetlands, but dust from nearby roads can alter pH in fens and smother small plants such as bryophytes. Livestock trample and destroy bryophyte cover. Commercial collecting of peat depletes bryophyte diversity in fens, although some species require periodic disturbance. Many peatlands are converting to forest in the absence of fire and few new peatlands are forming. Scientific collecting can also deplete populations of rare mosses such as Polytrichum strictum.
Conservation Considerations: Revisit known localities to reconfirm presence of populations, and conduct searches for new populations. At known sites or in potential habitat, manage peatlands to maintain hydrology, peat formation processes, and fen species composition.
Conservation rankings: Global: G4; National: NNR. California: SNR; Montana: SNR; Oregon: S1, List 2; Washington: S2, Working List.
Preparer: John A. Christy
Date Completed: June 2007
Updated by: Rob Huff
Date Completed: August 2011
Update removed Eugene BLM as suspected for this species; lack of habitat.
Christy, J.A. & D.H. Wagner. 1996. Guide for the identification of rare, threatened or sensitive bryophytes in the range of the northern spotted owl, western Washington, western Oregon and northwestern California. USDI Bureau of Land Management, Oregon-Washington State Office, Portland. 222 pp.
Crum, H. & L.E. Anderson. 1981. Mosses of Eastern North America. 2 volumes. Columbia University Press, New York. 1328 pp.
Frye, T.C. 1910. The Polytrichaceae of western North America. Proceedings of the Washington Academy of Sciences 12: 271-328.
_______. 1937. Family Polytrichaceae. Pp. 99-128 in: Grout, A.J. Moss Flora of North America North of Mexico. Volume 1. Published by the author. Newfane, Vermont.
Hutten, M., A. Woodward & K. Hutten. 2005. Inventory of the mosses, liverworts, hornworts, and lichens of Olympic National Park, Washington: species list. U.S. Geological Survey, Scientific Investigations Report 2005-5240. 78 pp.
Ireland, R.R. 1982. Moss Flora of the Maritime Provinces. National Museum of Natural Sciences, Publications in Botany. 13: 1-738. National Museum of Natural Sciences, Ottawa.
Lawton, E. 1971. Moss Flora of the Pacific Northwest. Hattori Botanical Laboratory, Nichinan, Japan. 362 pp.
Merrill, G.L.S. 2007. Polytrichum. Pp. 133-140 in: Flora of North America Editorial Committee. Flora of North America north of Mexico. Volume 27. Oxford University Press, New York. 713 pp.
Norris, D.H. & J.R. Shevock. 2004a. Contributions toward a bryoflora of California: I. A specimen-based catalogue of mosses. Madroño 51: 1-131.
Oregon Natural Heritage Information Center. 2007. Rare, threatened and endangered species of Oregon. Oregon Natural Heritage Information Center, Oregon State University. Portland. 100 pp.
Vitt, D.H., J.E. Marsh & R.B. Bovey. 1988. Mosses, Lichens & Ferns of Northwest North America. University of Washington Press, Seattle. 296 pp.
Washington Natural Heritage Program. 2005. Working list of mosses. Washington Department of Natural Resources, Olympia.