|Swauk Forest Discovery Trail, Wenatchee Mountains, Washington|
Arnica cordifolia is a species of arnica in the sunflower family, known by the common name heartleaf arnica. It is native to western North America from Alaska to California to New Mexico, as far east as Ontario and Michigan. It is a plant of many habitat types, including coniferous forests and mountain meadows.
This is a rhizomatous perennial herb producing one or more erect stems reaching a maximum height near half a meter. It has two to four pairs of leaves on the stem, each on a long petiole. The leaves are heart-shaped to arrowhead-shaped and finely toothed along the edges. The inflorescence bears one or more daisylike flower heads lined with white-haired phyllaries and sometimes studded with resin glands. The center of each head contains golden yellow disc florets and a fringe of bright golden ray florets approaching 3 centimeters in maximum length.
The fruit is a hairy achene up to a centimeter long, not counting its off-white pappus. Seeds are dispersed on the wind. An individual plant can live twelve years, surviving periodic wildfire by resprouting from its long, slender rhizome afterward.
- The International Plant Names Index
- Calflora taxon report, University of California, Arnica cordifolia Hook. heart leaved arnica, heartleaf arnica
- Biota of North America Program 2014 state-level distribution map
- Flora of North America Vol. 21 Page 374 Heartleaf arnica, Arnica cordifolia Hooker, Fl. Bor.-Amer. 1: 331. 1834.
- Ecology Fire Ecology
- Media related to Arnica cordifolia at Wikimedia Commons
- Jepson Manual Treatment
- United States Department of Agriculture Plants Profile
- Calphotos Photo gallery, University of California
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