Arnica chamissonis, commonly known as Chamisso arnica, is a perennial herb native to a variety of habitats in western North America, including moist meadows, grassy slopes, and the understory of coniferous forests from sea level to alpine zones. It is particularly prevalent in montane to subalpine regions, extending from Alaska through most of Canada and into the western United States. Chamisso arnica typically reaches up to 30 inches in height and features yellow, daisy-like flowers with a prominent central disk and ray florets, blooming from late spring to early fall. The foliage is bright green, with leaves arranged in pairs along the stems.

Chamisso arnica is valued for its showy yellow flowers and is used in wildflower gardens, naturalized areas, and restoration projects. It is also appreciated for its medicinal properties, as it contains the toxin helenalin, which is used in homeopathic preparations for its anti-inflammatory effects. In cultivation, it prefers full sun to partial shade and requires well-drained soils with consistent moisture. While it is not typically grown in traditional garden settings, its ease of maintenance and tolerance of cold climates make it a suitable choice for naturalistic plantings. Care should be taken when handling this plant, as helenalin can be irritating to the skin and harmful if ingested.CC BY-SA 4.0