SPECIES FACT SHEET
Common Name: Tundra thread-moss, tundra pohlia moss
Scientific Name: Pohlia tundrae
Division: Bryophyta
Class: Bryopsida
Order: Bryales
Family: Bryaceae
Technical Description: Plants glossy, compact, 2-5 (15) mm tall, green
above and red to black below, branched or unbranched. Leaves (0.6) 0.8-1.1 (1.4) mm long, (0.2) 0.3-0.4 (0.5)mm wide, narrowly to broadly
lanceolate, erect to spreading when dry, erect spreading when wet, acute
at the tips, not keeled, decurrent or not decurrent in dwarf plants;
margins plane to reflexed when dry, plane when wet, without
differentiated cells, the margins subentire to strongly toothed in the
upper 1/2-1/3; costa ending below the apex or percurrent; leaf cells
rectangular or rhombic, sometimes vermicular, thin-walled, basal cells
rectangular or rhombic, quadrate where attached to the stem.
Propagulae (gemmae) obconic, whitish to reddish brown, produced in
abundant and conspicuous clusters in uppermost leaf axils, more than
300 μm long, narrowly cylindrical at base with 2-6 well-developed bladelike (laminate) leaf primordia. Seta 1-1.5 cm long, orange to orange-red.
Capsule nodding, short to elongated and pear-shaped (pyriform), with a
neck Distinctive characters: (1) short stems, (2) leaves glossy when dry,
and (3) large propagulae. Similar species: Pohlia drummondii (1)
produces fewer propagulae but more capsules than P. tundrae, (2) its
stems and propagulae are typically red. Sterile specimens of these two
species may be impossible to separate without propagulae. Pohlia
proligera (1) is very glossy and (2) its propagulae are vermicular, looking
like masses of tomentum and lacking laminate leaf primordia. Pohlia
camptotrachela and P. annotina are not glossy. Other descriptions and
illustrations: Shaw 1981a: 65; Shaw 1981b: 47; Shaw 1982: 264.
Life History: Details for Pohlia tundrae are not documented. The
protonema is inconspicuous, forming buds and shoots in the usual
fashion of moss growth and development. Plants are often sterile but
propagulae are abundant (Shaw 1981a). In these cases dispersal is
limited to vegetative propagation via the propagulae, and gene flow may
be limited.
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Range, Distribution, and Abundance: Alaska, British Columbia,
Washington, Oregon, California, Idaho, Montana and south in the Rocky
Mountains to Arizona, disjunct in Austria (Hill et al. 2006).
National Forests: documented from Mt. Hood NF (Shaw 1981a, 1981b);
suspected on all forests in Oregon and Washington with subalpine to
alpine habitats. Documented from Mt. Rainier National Park (Shaw
1981a). BLM Districts: none documented or suspected because of lack of
habitat.
Reportedly common in alpine areas (Shaw 1981a) but seldom collected in
the Pacific Northwest. Probably undercollected.
Habitat Associations: Forming dense, compact sods 2-3 mm tall or
mixed with other mosses on wet acid soil (pH 5.0-6.0; Shaw 1981a) or
along snowmelt streamlets in subalpine and alpine habitats. Less
frequently on road and trail banks below the tree line, where usually
mixed with other mosses. Elevations range from 6000-8000 feet.
Sometimes
abundant.
Plant
associations
include
Phyllodoce
empetriformis and Cassiope mertensiana heath, and Pinus albicaulis,
Tsuga mertensiana, Abies lasiocarpa, and possibly Abies amabilis
associations. Associated bryophytes may include Pohlia drummondii,
Pohlia camptotrachela, Pohlia ludwigii, Bartramia ithyphylla, Conostomum
tetragonum, and Gymnomitrion.
Threats: Habitats in the Pacific Northwest are usually remote and visited
by few people. Rock climbing, trail construction or maintenance and
hiking may impact Pohlia tundrae locally but not over large areas of
subalpine and alpine habitat. However, air pollution and climate change
are serious long-term threats. Species growing on peaks and ridgetops
are subject to accumulation of aerosols from cloud interception. Longterm air quality monitoring could identify possible threats and impacts.
Pohlia tundrae is one of a suite of bryophytes restricted to alpine and
subalpine habitats in the Pacific Northwest, and populations south of the
Canadian border may be at risk because of rising temperatures and loss
of alpine habitat.
Conservation Considerations: Revisit known localities and monitor the
status of the populations. Search for new populations on federal lands.
Protection of known sites from recreational activities, particularly alpine
hiking and rock climbing, will minimize risk to populations.
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Conservation rankings: Global: G2G3; National: NNR. British Columbia:
S1S3, Blue List; California: S2.3, List 2; Oregon: S1, List 3; Washington:
NNR.
Preparer: John A. Christy
Date Completed: June 2007
Revised by Candace Fallon, February 2011
(Revision only adds Attachment 1, Photos)
ATTACHMENTS:
(1)
Photos
References
Hill, M.O., N. Bell, M.A. Bruggeman-Nannenga, M. Brugués, M.J. Cano,
J. Enroth, K.I. Flatberg, J.-P. Frahm, M.T. Gallego, R. Garilleti, J.
Guerra, L. Hedenäs, D.T. Holyoak, J. Hyvönen, M.S. Ignatov, F. Lara,
V. Mazimpaka, J. Muñoz & L. Söderström. 2006. An annotated
checklist of the mosses of Europe and Macaronesia. Journal of
Bryology 28: 198-267.
Norris, D.H. & J.R. Shevock. 2004. Contributions toward a bryoflora of
California: I. A specimen-based catalogue of mosses. Madroño 51: 1131.
Oregon Natural Heritage Information Center. 2007. Rare, threatened and
endangered species of Oregon. Oregon Natural Heritage Information
Center, Oregon State University. Portland. 100 pp.
http://oregonstate.edu/ornhic/2007_t&e_book.pdf
Shaw, A.J. 1981a. Pohlia andrewsii and P. tundrae, two new arctic-alpine
propaguliferous species from North America. Bryologist 84: 65-74.
_______. 1981b. A taxonomic revision of the propaguliferous species of
Pohlia (Musci) in North America. Journal of the Hattori Botanical
Laboratory 50: 1-81.
Shaw, J. 1982. Pohlia Hedw. (Musci) in North and Central America and
the West Indies. Contributions From the University of. Michigan
Herbarium 15: 219-295.
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Attachment 1 – Photos
All photos by J. Harpel, under contract with the Oregon/Washington Bureau of Land
Management.
Alar and basal cells
Upper medial cells
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Leaf
Perigonum
Leaf apex
Whole mount wet
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