SPECIES FACT SHEET
Common Name: Platyhypnidium moss
Scientific Name: Platyhypnidium riparioides
Recent synonym: Eurhynchium riparioides, Rhynchostegium riparioides
Phylum: Bryophyta
Class: Bryopsida
Order: Hypnales
Family: Brachytheciaceae
Technical Description: Shoots to 2 mm wide, prostrate, often curved,
with a glossy or metallic sheen, green, yellowish-green, brownish-green
or copper-colored above, blackening below, 2-15 cm long, irregularly
branched. Leaves 1.4-2.5 x 0.8-2 mm, broadly ovate-lanceolate to nearly
round, spreading, variously plane, concave, infolded, or loosely twisted
near the tip, often oriented somewhat horizontally and giving the shoots
a loosely flattened appearance, leaves sometimes lacerated or stripped off
by stream scour; costa 1/2 to 3/4 the length of the leaf, sometimes
extending nearly to the apex, sometimes forked, often ending in a short
spine or tooth at the tip; apex of leaves rounded; margins plane,
serrulate nearly to base; median leaf cells long and narrow, 40-100 x 4-5
μm. Capsules uncommon. Distinctive characters: (1) Robust matformer in and along streams, (2) leaves broadly rounded with serrulate
margins, (3) metallic green to brownish coppery sheen. Similar species:
Hygrohypnum species occur in the same habitat and may have similar
orbicular leaves, but never have serrulate margins. Other descriptions
and illustrations: Crum 1983: 313; Crum & Anderson 1981: 1072;
Lawton 1971: 302; Sharp et al. 1994: 939; Smith 1978: 603.
Life History: Details for this species are not documented. The
protonema is inconspicuous, forming buds and shoots in the usual
fashion of moss growth and development. Capsules are uncommon, but
fruiting in summer and fall. Most bryophytes in splash zone habitats are
limited to vegetative reproduction, but tend to occur in large monotypic
mats that produce many viable fragments for regeneration.
Range, Distribution, and Abundance: Widespread in Northern
Hemisphere, circumboreal and south to North Africa and northern South
America. In the Pacific Northwest, British Columbia south to California,
east to Montana.
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Documented on: National Forests: Columbia River Gorge NSA, Siuslaw.
BLM Districts: Coos Bay, Eugene.
Widespread but uncommon, probably undercollected.
Habitat Associations: Aquatic to emergent, forming mats on rocks,
wood, or roots of trees in streams or in spray zone of streams and
waterfalls. Partial to full shade. Elevation sea level to about 3000 feet.
Forest types include Pseudotsuga menziesii, Tsuga heterophylla, and
Picea sitchensis associations.
Threats: Road construction, recreational climbing in streambeds
(canyoning or canyoneering) and upstream activities such as logging,
road construction, and dredging that cause excessive siltation could be
detrimental. Water diversion would probably decimate populations. It is
unlikely that grazing has much effect other than possible siltation
problems.
Conservation Considerations: Because Platyhypnidium riparioides is
attached to rocks and other substrates in stream beds, riparian buffers
alone may not adequately protect populations because of sediment
transport within stream channels. Wagner (1997) reported several
populations of Platyhypnidium in stream channels on the Eugene BLM
District, but Goldenberg (2004) could not relocate some of these and
suspected that siltation from nearby logging on private land had buried
them. Control of silt-causing activity upstream may be the only way to
protect this species, and may not be possible where private lands are
interspersed with public lands.
Preparer: John A. Christy
Date Completed: May 2006
Updated by Camille Duncan in February 2010 (Update added Attachment 1:
Photos, to the Species Fact Sheet.)
ATTACHMENTS:
(1) Photos
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References
Crum, H. 1983. Mosses of the Great Lakes Forest. 3rd edition.
University of Michigan Herbarium, Ann Arbor. 417 pp.
_______ & L.E. Anderson. 1981. Mosses of Eastern North America. 2
volumes. Columbia University Press, New York. 1328 pp.
Goldenberg, D. 2004. Sighting form for Platyhypnidium riparioides, Wolf
Creek tributary. Eugene District, Bureau of Land Management.
Lawton, E. 1971. Moss Flora of the Pacific Northwest. Hattori Botanical
Laboratory, Nichinan, Japan. 362 pp.
Montana Natural Heritage Program. 2003. Plant species of concern.
Resource Information System, Montana State Library.
http:// nhp.nris.state.mt.us/plants/reports/2003_PSoC_List.pdf
Oregon Natural Heritage Information Center. 2004. Rare, threatened and
endangered species of Oregon. Oregon Natural Heritage Information
Center, Oregon State University. Portland. 104 pp.
http://oregonstate.edu/ornhic/2004_t&e_book.pdf
Sharp, A.J., H. Crum & P.M. Eckel (eds). 1994. The Moss Flora of Mexico.
2 volumes. Memoirs of the New York Botanical Garden 69: 1-1113.
Smith, A.J.E. 1978. The Moss Flora of Britain and Ireland. Cambridge
University Press, Cambridge. 706 pp.
Wagner, D.H. 1997. Inventory of bryophytes of Wolf Creek Watershed,
Eugene District, Bureau of Land Management, Lane County, Oregon.
Report to Eugene BLM District. Northwest Botanical Institute,
Eugene. 38 pp + appendices.
Washington Natural Heritage Program. 2005. Working list of rare
mosses.
http://www.dnr.wa.gov/nhp/refdesk/lists/ mosses.html
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Attachment 1: Photos
All photos by Dr. Judy Harpel, under contract with the Oregon/Washington Bureau of
Land Management
Whole mount dry
Whole mount wet
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Whole mount with sporophyte
Sporophyte close-up
Stem leaf
Branch leaf
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Stem leaf apex
Branch leaf apex
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Stem leaf alar and basal cells
Branch leaf alar and basal cells
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Stem leaf upper medial cells
Branch leaf upper medial cells
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