Arnica genus --- Aster subfamily 3.1
Aster 3.1 (Genus A to F) -- Aster 3.2 (Genus G to O) -- Aster 3.3 (Genus P to R) -- Aster 3.4 (Genus S to Z)
Chamisso arnica (Arnica chamissonis) -- in July -- Rollins Pass Road, Gilpin County, CO
Chamisso arnica (Arnica chamissonis) -- in August -- Kilpecker Road, Red Feather Lakes Area, Larimer County, CO
heartleaf arnica (Arnica cordifolia) -- in May -- Lory State Park, CO
foothills arnica (Arnica fulgens) -- in May -- South Valley Loop Trail, Lory State Park, CO
foothills arnica (Arnica fulgens) -- in May -- Mesa Trail, South Mesa Trailhead, Boulder County, CO
foothills arnica (Arnica fulgens) -- in July -- Buffalo Pass Road, Jackson County, CO
smallhead arnica (Arnica graciis) -- in August -- Mount Zirkel Wilderness, Jackson County, CO
broadleaf arnica (Arnica latifolia) -- in August -- Michigan Ditch Trail, Colorado State Forest State Park, CO
broadleaf arnica (Arnica latifolia) -- in June -- Bridal Veil Falls Trail, RMNP, CO
broadleaf arnica (Arnica latifolia) -- in June -- Ohio Pass Road, Gunnison County, CO
hairy arnica (Arnica mollis) -- in July -- Old Fall River Road, Rocky Mountain National Park, CO
hairy arnica (Arnica mollis) -- in July -- Wheeler Peak Campground, Great Basin National Park, NV
hairy arnica (Arnica mollis) -- in July -- Montgomery Pass Road, Jackson County, CO
hairy arnica (Arnica mollis) -- in August -- Snowy Range, Medicine Bow National Forest, WY
hairy arnica (Arnica mollis) -- in July -- Rollins Pass Road, Gilpin County, CO
Rydberg's arnica (Arnica rydbergii) -- in July -- Vedauwoo Recreation Area, near Laramie, WY
twin arnica (Arnica sororia) -- in June -- Glacier National Park, MT