Burke: Arnica latifolia vs. Arnica rydbergii

	Arnica latifolia	Arnica rydbergii
	broad-leaved arnica, mountain arnica, daffodil leopardbane	Rydberg's arnica, subalpine arnica, subalpine leopardbane
Habit	Perennial, 1-6 dm. tall, glandular at least above.	Perennial from short, scaly rhizomes, the stems clustered, 1-3 dm. tall.
Leaves	Broad, long-petiolate basal leaves sometimes on short separate stalks; cauline leaves 2-4 pairs, lance-elliptic or broader, rarely cordate, more or less toothed, 2-14 cm. long and 1-8 cm. wide, the middle ones larger than the lower.	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 1-several; involucre 7-18 mm. high, more or less glandular; pappus white, barbellate.	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	Achenes glabrous, at least toward the base.	Achene densely covered throughout with short, soft hairs

	Arnica latifolia	Arnica rydbergii
Identification notes	The similar Arnica cordifolia has larger heads, frequently solitary; its leaves and achenes are pubescent.
Flowering time	June-August	June-August
Habitat	Common in forest openings and meadows, and open, rocky areas from middle to high elevations in the mountains.	Dry meadows and open slopes at high elevations in the mountains.
Distribution	Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains. [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	Native
Conservation status	Not of concern	Not of concern
Sibling taxa	A. chamissonis, A. cordifolia, A. discoidea, A. fulgens, A. gracilis, A. lanceolata, 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: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria, Turner Photog. 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 rydbergii

broad-leaved arnica, mountain arnica, daffodil leopardbane

Rydberg's arnica, subalpine arnica, subalpine leopardbane

Habit

Perennial, 1-6 dm. tall, glandular at least above.

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

Leaves

Broad, long-petiolate basal leaves sometimes on short separate stalks; cauline leaves 2-4 pairs, lance-elliptic or broader, rarely cordate, more or less toothed, 2-14 cm. long and 1-8 cm. wide, the middle ones larger than the lower.

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 1-several;

involucre 7-18 mm. high, more or less glandular;

pappus white, barbellate.

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

Achenes glabrous, at least toward the base.

Achene densely covered throughout with short, soft hairs