SPECIES FACT SHEET
Common Name: Shieldscale liverwort
Scientific Name: Peltolepis quadrata
Division: Hepatophyta
Class: Hepatopsida
Order: Marchantiales
Family: Monosoleniaceae
Technical Description: Plants thalloid. Thallus bright to dark green,
translucent, fleshy but not firm, 3-7 mm wide and 1-2 cm long; margins
usually reddish or purplish, upturned. Dorsal surface of thallus with
pattern of irregular polygons, the pores to the air chambers conspicuous
and stellate but not much bulging or elevated, the epidermal cells with
indistinctly thickened walls at corners (trigones), with or without oil
bodies. Ventral surface of thallus convex. Ventral scales whitish to
purplish, bluntly elongate-triangular (lingulate) scales, not obviously
exposed along the margins. Gemmae none. Stalk of receptacle 5-10 (15)
mm long, pale green to purplish at base, with two linear furrows.
Receptacle (carpocephalum) pale green or purplish, convex, about 3 mm
wide, deeply (4) 5-6 (8) -lobed, the lobes inflated. Sporangia 1 per
receptacle, brown, splitting open irregularly without an operculum.
Distinctive characters: (1) Thallus medium-sized, light green and
somewhat translucent but reddish or purplish along the edges, (2)
thallus margins upturned, purplish, with ventral scales not protruding,
(3) receptacle stalks greenish to purplish at base and with linear furrows,
and (4) carpocephalum deeply lobed, the lobes inflated. Similar species:
Athalamia hyalina has (1) thalli 2-6 mm wide and less than 1.5 cm long,
grayish green (2) thallus margins upturned with ventral scales projecting
conspicuously, (3) receptacle stalks colorless and without furrows, and
(4) carpocephala usually with only four lobes Other descriptions and
illustrations: Evans 1923: 37 [as Peltolepis grandis]; Frye andClark
1937: 54 [as Peltolepis grandis]; Schuster 1992: 115; Schofield 2002:
167.
Life History: Details for Peltolepis quadrata are not documented. In
thalloid liverworts, the protonema is reduced and short-lived.
Carpocephala are somewhat longer-lived in thalloid liverworts than in
leafy liverworts. Because it occurs at high elevations, capsules develop in
late summer. It is probably a poor competitor with vascular plants, and
populations probably disappear with the passage of time.
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Range, Distribution, and Abundance: Interruptedly circumboreal,
where mostly restricted to arctic or alpine areas. South to Europe (absent
from U.K.), Russia, China, Japan. In North America, from Alaska south
to Oregon and the southern Rocky Mountains.
National Forests: documented on Wallowa-Whitman NF (Elkhorn Ridge
and suspected in the Wallowa Mountains); suspected on any National
Forests in Washington with higher-elevation exposures of calcareous or
ultramafic bedrock. BLM Districts: suspected by Vale.
Rare and local throughout much of its range.
Habitat Associations: Forming small mats on moist, exposed to shady
soil or on ledges and crevices in talus slopes and outcrops. Usually a
calciphile but sometimes occurring on igneous rocks (Schuster1992). By
extension, calciphilous bryophytes sometimes also occur on ultramafic
rocks that are also rich in base elements. In the Pacific Northwest
Peltolepis is alpine to subalpine, with a single known site at an elevation
of about 7000 feet (Wagner 1996). Forest types range from Abies
lasiocarpa, Pinus albicaulis, to above timberline.
Threats: Threats may include trail maintenance, plant succession,
commercial quarrying of limestone, and climate change. Although threats
may be low in remote areas and higher elevations, populations of
Peltolepis are small, discontinuous, and subject to local catastrophic
loss. Peltolepis probably does not compete well with vascular plants.
High-elevation habitats are at particular risk for long-term climate
change.
Conservation Considerations: In Oregon and Washington, exposures of
calcareous rock at high elevation are rare (Brooks 1989). Most of these
areas are relatively remote and underexplored bryologically. Conduct
surveys in suitable habitat within known and suspected range, and
manage known sites.
Conservation rankings: Global: G4; National: NNR. Oregon: S1, List 2.
Preparer: John A. Christy
Date Completed: June 2006. Revised May 2007 with edits from Rob Huff, Russ
Holmes, and Daphne Stone.
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Updated in May 2009 by Candace Fallon (Update added Attachment 1, Photos, to the
Species Fact Sheet); updated in August 2011 by Rob Huff, adding Vale BLM as
suspected.
ATTACHMENTS:
(1)
Photos
References
Brooks, H.C. 1989. Limestone deposits in Oregon. Oregon Department of
Geology and Mineral Industries Special Paper 19: 1-72.
Evans, A.W. 1923. Sauteriaceae. North American Flora 14: 35-37 [as
Peltolepis grandis].
Frye, T.C. & L. Clark. 1937. Hepaticae of North America. Volume 1.
University of Washington Publications in Biology 6: 1-162 [as
Peltolepis grandis].
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
Schofield, W.B. 1994. Rare and endangered bryophytes in British
Columbia. Pp. 71-75 in: L.E. Harding & E. McCullen (eds.).
Biodiversity in British Columbia: our changing environment.
Environment Canada, Canadian Wildlife Service. 426 pp.
_______. 2002. Field guide to liverwort genera of Pacific North America.
University of Washington Press, Seattle. 228 pp.
Schuster, R.M. 1992. The Hepaticae and Anthocerotae of North America.
Volume 6. Columbia University Press, New York. 937 pp.
Wagner, D.H. 1996. Inventory of bryophytes of Elkhorn Ridge, WallowaWhitman National Forest, Oregon. Report to USDA Forest Service,
Wallowa-Whitman National Forest. Northwest Botanical Institute. 18
pp.
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Attachment 1 – Photos
All photos by Dr. David Wagner, under contract with the Oregon/Washington Bureau of
Land Management.
Spore tetrad
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Spore and elater
Capsule wall
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