| Arnica sororia | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Asterids |
| Order: | Asterales |
| Family: | Asteraceae |
| Genus: | Arnica |
| Species: | A. sororia |
| Binomial name | |
| Arnica sororia | |
Arnica sororia is a North American species of flowering plant known by the common name twin arnica. [1] It is native to Western Canada (British Columbia, Alberta, Saskatchewan) and the Western United States (Washington, Oregon, California, Nevada, Utah, Idaho, Montana, Wyoming, South Dakota). [2] It grows in grasslands and in conifer forests, [3] as well as the sagebrush steppe. [4]
Arnica sororia is a rhizomatous perennial herb producing one or more hairy, glandular stems 10 to 50 centimeters (4 to 19+1⁄2 in) tall. There are a few to several pairs of broadly lance-shaped leaves along the stem, [4] the lower ones borne on petioles. Leaves may reach up to 14 cm long. [5]
The inflorescence consists of a daisy-like flower head, rarely more than one per stem. [4] These are lined with phyllaries coated in glandular hairs. The flower head has a center of glandular yellow disc florets and a fringe of yellow ray florets. The fruit is an achene a few millimeters long with a white pappus. [5]
