Chamisso Arnica, Leafy Arnica, Leafy Leopardbane, Meadow Arnica, Narrowleaf Arnica, Silvery Arnica: Arnica chamissonis (Synonyms: Arnica chamissonis ssp. chamissonis, Arnica chamissonis ssp. foliosa, Arnica chamissonis ssp. incana, Arnica chamissonis var. andina, Arnica chamissonis var. chamissonis, Arnica chamissonis var. foliosa, Arnica chamissonis var. incana, Arnica chamissonis var. interior, Arnica chamissonis var. maguirei)
Heart-leaf Arnica, Heart-leaf Leopardbane: Arnica cordifolia (Synonyms: Arnica cordifolia var. cordifolia, Arnica cordifolia var. pumila) - Stem leaves generally number 2-3 pairs, the blades toothed and heart-shaped. Flower heads have a yellow central disc surrounded by 8 to 12 yellow ray flowers. Tips of ray flowers pointed.
Rayless Arnica, Rayless Leopardbane: Arnica discoidea (Synonyms: Arnica discoidea var. eradiata, Arnica grayi, Arnica parviflora, Arnica parviflora ssp. alata, Arnica parviflora ssp. parviflora) - Stem leaves number 2-4 pairs. The blades are ovate to somewhat heart-shaped, measuring 4-8 cm long and 1.5-5 cm wide. Flower heads entirely discoid, the rays lacking.
Sticky Arnica, Sticky-leaf Arnica: Arnica diversifolia (Synonym: Arnica xdiversifolia, Arnica ovata)
Foothill Arnica, Hillside Arnica, Orange Arnica, Shining Leopardbane: Arnica fulgens - Stem leaves number 2-4 pairs, the narrow blades about 3-10 times longer than wide. Flower heads broad with 10-23 rays (each 1.5-2.5 cm long).
Clasping Arnica, Columbia Gorge Arnica, Streambank Arnica, Streambank Leopardbane: Arnica lanceolata ssp. prima (Synonyms: Arnica amplexicaulis, Arnica amplexicaulis ssp. amplexicaulis, Arnica amplexicaulis var. amplexicaulis, Arnica amplexicaulis var. piperi, Arnica amplexifolia ssp. prima) - Stem leaves number 5-12. Leaves generally toothed. Flower heads have a yellow central disc surrounded by 8 to 14 yellow ray flowers. Leaves narrow to broad, measuring up to 6 cm wide.
Broadleaf Arnica, Broad-leaved Arnica, Daffodil Leopardbane, Mountain Arnica: Arnica latifolia (Synonym: Arnica latifolia var. latifolia) - Stem leaves number 2-4 pairs, the broad leaves about 1.5-2 times longer than wide (up to 8 cm wide). The lower leaves are rarely heart-shaped. A showy wildflower with opposite, hear-shaped to lance-shaped leaves. The stem and basal leaves are similar in size. The flower heads are yellow, with both rays and disk flowers.
Hairy Arnica, Cordilleran Arnica, Cordilleran Leoparbane: Arnica mollis - Uncommon in the Columbia River Gorge. Typically found in higher elevations meadows outside the Gorge.
Rydberg's Arnica, Subalpine Arnica: Arnica rydgergii - Uncommon in the Columbia River Gorge or perhaps just outside this area. Stem leaves number 2-4 pairs, the narrow blades about 3-10 times longer than wide. Flower heads small with 7-10 rays (each 1-2 cm long).
Bunch Arnica, Foothills Arnica, Twin Arnica, Twin Leopardbane: Arnica sororia (Synonym: Arnica fulgens var. sororia) - Probably not occurring in the Columbia River Gorge or located around its eastern periphery.