Photo © Robert K. Moseley
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Lomatogonium rotatum (L.) Fries ex Fern.

Marsh felwort

Gentianaceae (Gentian family)

General Description: A glabrous annual or biennial herb with branched or unbranched stems 10-25 cm tall. Leaves are opposite, entire, and scattered on the stem; the lower ones spoon-shaped, the others more lance-shaped, and up to about 3 cm long. Flowers are white to bluish and borne singly at the top of branches or the upper leaf axils. The corolla is flat in outline, with 5 ovate, sharp pointed petals between 5-15 mm long, each one having a basal pair of distinctive, scale-like, fringed appendages. Sepals are conspicuous, linear, and usually exceed the corolla. The fruit is an oblong capsule with numerous small seeds.

Illustration.

Field Identification Tips: Marsh felwort can be recognized by its hairless habit, scattered pairs of opposite leaves, flat, white to bluish flowers borne on slender pedicels in the upper leaf axils, and leaf-like sepals usually longer than the petals. The restrictive habitat for this species in Idaho is another tip.

Phenology: Flowers August and September.

Photo © Robert K. Moseley
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Similar Species: Marsh felwort is sufficiently distinct that it should not be confused with other members of the gentian family found in Idaho.

Habitat: In Idaho, it occurs in spring-fed, alkaline, sometimes hummocky, meadows, fens, and streamside areas in the montane zone. Associated species include Potentilla fruticulosa, Salix spp., Juncus balticus, Carex simulata, C. aquatilis, C. nebrascensis, and Primula alcalina.

Global Distribution: Circumpolar; in western North America from Alaska south to Alberta and in the Rocky Mountains from Idaho and Montana south to New Mexico. In eastern North America from Hudson Bay, south to Maine. Also in Greenland, Iceland, northern Europe and Siberia.

Idaho Distribution: Upper reaches of intermountain valley bottoms and tributaries in Custer and Lemhi counties in the east-central part of the state.

References:

Famous, N. C., and C. S. Campbell. 1985. Lomatogonium rotatum. In: The Nature Conservancy Element Stewardship Abstract [Data base]. Boston, MA: The Nature Conservancy, Eastern Regional Office.

Montana Natural Heritage Program. Montana rare plant field guide. Available at: http://nhp.nris.state.mt.us.