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Western Wetland Flora

Field Office Guide to Plant Species

Streambank Arnica
Arnica amplexicaulis Nutt.

JPG -- Species Photo JPG -- Distribution Map

Family: Composite (Compositae)
Flowering: July-August
Field Marks: This species has 5-12 pairs of opposite, toothed leaves on the stem and pointed bracts subtending the flower heads.
Habitat: Along streams, moist woods.
Habit: Perennial herb with much branched rhizomes.
Stems: Upright, usually unbranched, up to 2 1/2 feet tall, usually glandular-hairy, sometimes more or less smooth.
Leaves: Opposite, simple, with 5-12 pairs on the stem, lanceolate to narrowly ovate, up to 4 1/2 inches long, pointed or somewhat rounded at the tip, rounded at the base, toothed, glandular-hairy or nearly smooth.
Flowers: Crowded into heads up to 2 inches across, consisting of 8-14 pale yellow rays and a yellow disk; each head subtended by narrow pointed bracts 1/2-3/4 inch long.
Sepals: 0.
Petals: 5, some of them united to form rays 1/2-1 inch long, others united to form tubular flowers in a central disk.
Stamens: 5.
Pistils: Ovary inferior, hairy.
Fruits: Achenes sparsely hairy, with a tuft of tawny-colored soft bristles at the tip.

Return to Species List -- Group 7
Next Species -- Leafy Arnica (Arnica chamissonis)

U.S. Department of the Interior | U.S. Geological Survey
URL: http://www.npwrc.usgs.gov/resource/plants/florawe/species/7/arniampl.htm
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Page Last Modified: Saturday, 02-Feb-2013 06:26:53 EST
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