Northern Prairie Wildlife Research Center
Western Wetland Flora
Field Office Guide to Plant Species
Arnica amplexicaulis Nutt.
- 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.
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