SPECIES FACT SHEET
Common Name: Polia moss, sparse hummock moss, nodding bog moss
Scientific Name: Pohlia sphagnicola
Division: Bryophyta
Class: Bryopsida
Order: Bryales
Family: Bryaceae
Technical Description: Plants erect, mostly unbranched, 1-3 cm long,
with dark reddish-brown stems showing between the leaves. Leaves 1-1.5
mm long, dark green, narrow, straight and appressed or contorted, entire
or weakly serrulate near apex. Dioicous, with only archegonia on plants
bearing capsules. Capsules 3-5 mm long, pendant, brown, on brown
setae to 3 cm. Distinctive characters: (1) Small, stiff-looking
unbranched shoots among packed heads of Sphagnum, especially S.
fuscum and S. capillifolium, (2) on top of Sphagnum hummocks, with (3)
small, scattered pendant capsules on long threadlike setae and (4) only
archegonia present on fertile plants. Similar species: Pohlia nutans, a
common species on rotting wood and duff of moist to dry forests,
especially at middle to higher elevations, sometimes occurs on top of
Sphagnum hummocks in both coastal and montane fens. The two species
are impossible to tell apart without fertile plants. P. nutans is has (1)
both antheridia and archegonia present on the same plant but in
different locations on the plant (paroicous), (2) longer leaf cells, and (3)
serrate leaves. Some bryologists think that P. sphagnicola is only a poorly
developed form of P. nutans, but Shaw (1982) demonstrated that the
differences between the two species are consistent. Other descriptions
and illustrations: Andrews 1935: 194; Nyholm 1958: 207; Crum and
Anderson 1981: 532; Shaw 1982: 225; Ireland 1982: 292; Christy and
Wagner 1996: VII-47.
Life History: Details for Pohlia sphagnicola are not documented. The
protonema is inconspicuous, forming buds and shoots in usual fashion
of moss growth and development.
Range, Distribution, and Abundance: Circumboreal. In the Pacific
Northwest, known from British Columbia, Washington and Oregon.
National Forests: none documented; suspected on all forests in the
region with suitable fen habitat. BLM Districts: none documented;
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suspected on the Salem and Coos Bay districts. Documented from the
Neskowin Marsh unit of the Nestucca Bay National Wildlife Refuge.
Rare throughout its range and much less common than P. nutans.
Confusion with P. nutans may cause P. sphagnicola to be either
undercollected or over-reported.
Habitat Associations: Occurring as individual shoots or small clusters
of shoots among the tightly-packed heads of Sphagnum fuscum and
Sphagnum capillifolium, on top of 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
moss Aulacomnium palustre, and the liverwort Mylia anomala. 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 Pohlia sphagnicola.
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: G2G3; National: NNR. British Columbia:
S2S3, Blue List; Oregon: S1, List 2; Washington: S1, Working List.
Preparer: John A. Christy
Date Completed: June 2007
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Revised by Lara Drizd, December 2012
(Revision only adds Attachment 1, Photos).
ATTACHMENTS:
(1)
Photos
References
Andrews, A.L. 1935. Family Bryaceae. Pp. 184-210 in: Grout, A.J. Moss
Flora of North America North of Mexico. Volume 2. Published by the
author. Newfane, Vermont.
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.
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.
Nyholm, E. 1954-1969. Illustrated Moss Flora of Fennoscandia. Volume
2. Musci. CWK Gleerup, Lund, and Natural Science Research Council,
Stockholm. 799 pp.
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, J. 1982. Pohlia Hedw. (Musci) in North and Central America and
the West Indies. Contributions From the University of. Michigan
Herbarium 15: 219-295.
Washington Natural Heritage Program. 2005. Working list of mosses.
Washington Department of Natural Resources, Olympia.
http://www.stage.dnr.wa.gov/nhp/refdesk/lists/mosses.html
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Attachment 1 – Photos
All photos by J. Harpel, under contract with the Oregon/Washington Bureau of Land
Management.
Whole dry mount
Whole wet mount
Whole dry mount
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Wet capsule
Dry capsule
Peristome teeth
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Leaf
Whole leaf
Alar and basal cells
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Stomata
Exothecial cells
Upper medial cells
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