Burke: Arnica dealbata vs. Arnica rydbergii

	Arnica dealbata	Arnica rydbergii
		Rydberg's arnica, subalpine arnica, subalpine leopardbane
Habit		Perennial from short, scaly rhizomes, the stems clustered, 1-3 dm. tall.
Leaves		Basal leaves petiolate, oblanceolate, 3- to 5-nerved, frequently on separate short shoots; cauline leaves opposite, 3-4 pairs, oblanceolate to lanceolate, 3- to 5-nerved, concentrated on the lower part of the stem, 3-10 cm. long and 5-25 mm. wide.
Flowers		Heads solitary or few, top-shaped; involucre 9-13 mm. high, its bracts pointed, glandular on the back with hairs on the margins; rays about 8, yellow, pistillate, 1-2 cm. long; disk flowers yellow, perfect; pappus white, barbellate.
Fruits		Achene densely covered throughout with short, soft hairs

	Arnica dealbata	Arnica rydbergii
Flowering time		June-August
Habitat		Dry meadows and open slopes at high elevations in the mountains.
Distribution	[WildflowerSearch map] [BONAP county map]	Occurring on both sides of the Cascades crest in Washington; British Columbia to northern California, east to Alberta and Colorado. [WildflowerSearch map] [BONAP county map]
Origin		Native
Conservation status		Not of concern
Sibling taxa	A. chamissonis, A. cordifolia, A. discoidea, A. fulgens, A. gracilis, A. lanceolata, A. latifolia, A. longifolia, A. mollis, A. nevadensis, A. ovata, A. parryi, A. rydbergii, A. sororia	A. chamissonis, A. cordifolia, A. discoidea, A. fulgens, A. gracilis, A. lanceolata, A. latifolia, A. longifolia, A. mollis, A. nevadensis, A. ovata, A. parryi, A. sororia
Web links	Local floras: CA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: BC, OR, WA Local Web sites: Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Arnica dealbata

Arnica rydbergii

Rydberg's arnica, subalpine arnica, subalpine leopardbane

Habit

Perennial from short, scaly rhizomes, the stems clustered, 1-3 dm. tall.

Leaves

Basal leaves petiolate, oblanceolate, 3- to 5-nerved, frequently on separate short shoots;

cauline leaves opposite, 3-4 pairs, oblanceolate to lanceolate, 3- to 5-nerved, concentrated on the lower part of the stem, 3-10 cm. long and 5-25 mm. wide.

Flowers

Heads solitary or few, top-shaped;

involucre 9-13 mm. high, its bracts pointed, glandular on the back with hairs on the margins;

rays about 8, yellow, pistillate, 1-2 cm. long;

disk flowers yellow, perfect;

pappus white, barbellate.

Fruits

Achene densely covered throughout with short, soft hairs