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.

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.

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, Wallowa-Whitman National Forest, Oregon. Report to USDA Forest Service, Wallowa-Whitman National Forest. Northwest Botanical Institute. 18 pp.

Attachment 1 – Photos

All photos by Dr. David Wagner, under contract with the Oregon/Washington Bureau of Land Management.

Spore tetrad

Spore and elater

Capsule wall

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