Mt. Shasta Arnica

Plants 20–50 cm. Stems branched (prominently ribbed, strongly stipitate-glandular; caudices woody). Leaves 5–10 pairs (main stems, 2–6 pairs on branches; basal withered by flowering), cauline; sessile; blades obovate-oblong to ovate-oblong, (1–)2–4(–5) × 1–3 cm, margins ± entire, apices acute, faces sparsely to densely pilose, densely stipitate-glandular. Heads 10–20. Involucres narrowly turbinate. Phyllaries 10–20, broadly lanceolate (stipitate-glandular). Ray florets 0. Disc florets 10–30; corollas cream; anthers yellow. Cypselae dark gray, 4.5–6.5 mm, stipitate-glandular; pappi usually white, rarely tawny, bristles barbellate to subplumose. 2n = 38.

Chrysopsis shastensis Jepson; Raillardella paniculata Greene

Arnica viscosa A. Gray, Proc. Am. Acad. 13: 374. 1878
Raillardella paniculata Greene, Erythea 3: 48. 1895.
Rootstock short; stem leafy, 3-5 dm. high, branched above, sulcate, glandular-hirsute; leaves small, the lower scale-like, those higher up 1-3 cm. long, sessile, oblong-ovate, entire, acute, rather thick, densely glandularor viscid-hirsute; heads solitary at the end of the leafy branches; involucre turbinate, rarely 1 cm. high and fully as broad, glandular-hirsute; bracts 1 1-15, lanceolate, acuminate; ray-flowers wanting; disk-corollas ochroleucous, the tube 2 mm. long, the throat 4 mm. long, and the lobes about 1 mm. long; achenes 5 mm. long, sulcate, glabrous or sparingly hirsute; pappus-bristles straw-colored, 5 mm. long, short-plumose.
Type locality: Mount Shasta, California. w
Distribution: Northern California and southern Oregon.

Arnica viscosa is an uncommon North American species of flowering plant in the family Asteraceae, known by the common name Mount Shasta arnica (not to be confused with the Shasta County arnica, A. venosa).