SPECIES FACT SHEET
Common Name: Braided frostwort, pointy whiteworm
Scientific Name: Gymnomitrion concinnatum
Division: Hepatophyta
Class: Hepatopsida
Order: Jungermanniales
Family: Gymnomitriaceae
Technical Description: Plants linear, 0.3-0.5 mm wide and 12-20 mm
long, widening slightly near the tips like a club, yellowish-brown to dull
greenish-white, forming densely-packed mats. Leaves erect, tightly
imbricate, arranged along stem in two opposite ranks resembling braids,
shallowly bilobed, the lobe tips sharply acute, the margins whitishtransparent (hyaline). When viewed under high magnification, the cuticle
is minutely papillose. Distinctive characters: (1) minute size, (2)
densely-packed linear shoots with leaves in two ranks, and (3) pale
yellowish-brown color except for a whitish fringe on some of the leaves.
Similar species: Some of the smaller species of Marsupella are similar to
Gymnomitrion but they are usually very dark brown to blackish and very
rarely have bleached margins on the leaves. Gymnomitrion obtusum has
(1) rounded leaf tips, (2) a pure pale green color, (3) better developed
hyaline margins around the leaf tips, and (4) smooth cuticles. Other
descriptions and illustrations: Frye & Clark 1943: p. 214; Mueller
1957: 796; Schuster 1974: 135; Smith 1990: 164; Christy and Wagner
1996: V-20; Paton 1999: 329; Doyle and Stotler 2006: 156; Bosanquet
2007.
Life History: Details for Gymnomitrion are not documented. In leafy
liverworts, the protonema is reduced and short-lived. Capsules are also
short-lived, produced on delicate transparent stems that collapse after
the capsules open, usually within a week of maturity. Capsules usually
develop in early summer, depending on elevation.
Range, Distribution, and Abundance: Circumboreal and bipolar, in
both eastern and western North America. In the Pacific Northwest,
known from British Columbia, Montana (Hong 2002), Washington,
Oregon, and California (Doyle and Stotler 2006).
National Forests: documented from the Mt. Hood NF, the Columbia River
Gorge NSA, and the Mt. Baker-Snoqualmie NF. Documented from
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Olympic National Park (Hong et al. 1989; Hutten et al. 2005). BLM
Districts: none documented.
Rare in the Pacific Northwest, probably undercollected.
Habitat Associations: On peaty soil of cliffs and rock outcrops, full
exposure or shaded. Little information is available on associated vascular
or bryophyte vegetation. In California it has been found between 375 and
6,000 feet elevation (Doyle and Stotler 2006), but in Oregon and
Washington it has only been found in subalpine parkland areas in Tsuga
mertensiana and Abies lasiocarpa associations.
Threats: Little is known about threats to Gymnomitrion concinnatum in
the Pacific Northwest. Sites where it is known in Oregon and Washington
indicate an affinity for mountainous areas that are still poorly explored,
so that its frequency and abundance across the landscape are not easily
assessed.
Conservation Considerations: Revisit known localities and monitor the
status of the populations. Search for new populations on federal lands.
Conservation rankings: Global: G5; National: NNR. California: SNR;
Oregon: S1, List 2. Washington has not yet compiled a working list of
rare liverworts.
Preparers: John A. Christy and David H. Wagner
Date Completed: June 2007
Updated in May 2009 by Candace Fallon (Update added Attachment 1, Photos, to the
Species Fact Sheet).
Edits: Rob Huff, November 2009
ATTACHMENTS:
(1)
Photos
2
References
Bosanquet, S. 2007. Gymnomitrion concinnatum. In: British mosses and
liverworts, a field guide. Provisional Publication, British Bryological
Society.
http://www.bryosoft.co.uk/fieldguide/accounts/liverworts/Gymnomi
trion concinnatum_PT.pdf
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.
Doyle, W.T. & R.E. Stotler. 2006. Contributions toward a bryoflora of
California III. Keys and annotated species catalogue for liverworts and
hornworts. Madroño 53: 89-197.
Frye, T.C. & L. Clark. 1943. Hepaticae of North America. Vol. 2.
University of Washington Publications in Biology 6: 163-336.
Hong, W.S. 2002. A key to the Hepaticae of Montana. Northwest Science
76: 271-285.
_______ K. Flander, D. Stockton & D. Trexler. 1989. An annotated
checklist of the liverworts and hornworts of Olympic National Park,
Washington. Evansia 6: 33-52. 1989.
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.
Mueller, K. 1957. Die Lebermoose Europas. Part 2. in Rabenhorst's
Kryptogamen Flora, Vol. 6, 3rd edition. Leipzig.
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
Paton, J.A. 1999. The liverwort flora of the British Isles. Harley Books,
Colchester, U.K. 626 pp.
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Schuster, R.M. 1974. The Hepaticae and Anthocerotae of North America.
Vol. 3. Columbia University Press, New York. 880 pp.
Smith, A.J.E. 1990. The Liverworts of Britain and Ireland. Cambridge
University Press, Cambridge. 362 pp.
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Attachment 1 – Photos
All photos by Dr. David Wagner, under contract with the Oregon/Washington Bureau of
Land Management.
General aspect
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Leaf
Leaf lobe tip
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Midleaf cells
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