Burke: Arnica ovata vs. Arnica discoidea

	Arnica ovata	Arnica discoidea
	sticky arnica, sticky-leaf arnica	rayless arnica, rayless leopardbane
Habit	Perennial from a freely rooting rhizome, the stems solitary or tufted, 1.5-4 dm. tall.	Perennial from long rhizomes, the stems mostly solitary, 2-5 dm. tall, glandular-puberulent and more or less long-hairy.
Leaves	Cauline leaves 3-4 pairs, mostly sessile, ovate to deltoid or elliptic, irregularly toothed, the middle ones the largest, with blades 4-8 cm. long and 2-6 cm. wide.	Long-petiolate, deltoid or sub-cordate basal leaves commonly on separate short shoots; cauline leaves 2-4 pairs, reduced upward, petiolate, ovate, 4-8 cm. long and 1.5-5 cm. wide, irregularly toothed, with long, soft hairs on both sides, pale beneath.
Flowers	Heads generally several, narrow, with few disk flowers; involucre 10-14 mm. high with pointed bracts, covered with stalked glands; rays about 8 or about 13, 1.5-2 cm. long; pappus straw-colored, sub-plumose.	Heads usually several, rayless; involucre 11-13 mm. high, with hairs and stalked glands throughout.
Fruits	Achene.

	Arnica ovata	Arnica discoidea
Identification notes		The similar rayless Arnica parryi has narrower leaves and the heads are nodding in bud.
Flowering time	July-September	June-August
Habitat	Rocky places from middle elevations to the subalpine and alpine.	Forest openings from middle elevations to the subalpine.
Distribution	Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to Montana and Utah. [WildflowerSearch map] [BONAP county map]	Occurring in the Cascades Mountains of Klickitat and Skamania counties in Washington; Washington to California, east to Nevada. [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. latifolia, A. longifolia, A. mollis, A. nevadensis, A. parryi, A. rydbergii, A. sororia	A. chamissonis, A. cordifolia, A. fulgens, A. gracilis, A. lanceolata, A. latifolia, A. longifolia, A. mollis, A. nevadensis, A. ovata, A. parryi, A. rydbergii, A. sororia
Web links	Local floras: BC, CA, OR, WA 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: CA, OR, WA 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

Arnica ovata

Arnica discoidea

sticky arnica, sticky-leaf arnica

rayless arnica, rayless leopardbane

Habit

Perennial from a freely rooting rhizome, the stems solitary or tufted, 1.5-4 dm. tall.

Perennial from long rhizomes, the stems mostly solitary, 2-5 dm. tall, glandular-puberulent and more or less long-hairy.

Leaves

Cauline leaves 3-4 pairs, mostly sessile, ovate to deltoid or elliptic, irregularly toothed, the middle ones the largest, with blades 4-8 cm. long and 2-6 cm. wide.

Long-petiolate, deltoid or sub-cordate basal leaves commonly on separate short shoots;

cauline leaves 2-4 pairs, reduced upward, petiolate, ovate, 4-8 cm. long and 1.5-5 cm. wide, irregularly toothed, with long, soft hairs on both sides, pale beneath.

Flowers

Heads generally several, narrow, with few disk flowers;

involucre 10-14 mm. high with pointed bracts, covered with stalked glands;

rays about 8 or about 13, 1.5-2 cm. long;

pappus straw-colored, sub-plumose.

Heads usually several, rayless;

involucre 11-13 mm. high, with hairs and stalked glands throughout.

Fruits

Achene.