Sphaeromeria ruthiae

Walter Fertig, Rare Plants of Zion National Park (2010)

Non-technical Description: Ruth’s chicken-sage is a low, aromatic subshrub with stems 30-70 cm long from a persistent woody base.  Leaves and twigs are gray to silvery from dense and closely appressed pubescence.  Lower stem leaves are up to 9 cm long and deeply 3-lobed or pinnately 5 lobed.  Middle and upper leaves are progressively smaller, narrower, and oval to linear with entire margins.  Flower heads are short-stalked and clustered in a leafy terminal panicle that is longer than wide.  Involucres are 4-4.5 mm long with 3-4 rows of silvery-pubescent bracts.  Ray flowers are absent.  Disk flowers are yellow and 1.8-2 mm long.  Achenes are glabrous to glandular and lack a pappus.  Flowering July-September.

Similar Species: Artemisia ludoviciana usually has longer stems, more finely divided leaves, and a more elongate inflorescence of numerous, spreading branches.

Habitat: Crevices of nearly vertical Navajo Sandstone cliff faces and ledges, often in partially to deeply shaded canyons at 4400-6550 ft (1340-2000 m). Some populations in Zion National Park occur on masonry surfaces and retaining walls (such as the switchbacks of Walter’s Wiggles).

Comments: Named in honor of Ruth Nelson, author of a popular wildflower guide to Zion NP and widow of Aven Nelson, pioneer taxonomist of Wyoming and western North America. Recent systematic research suggests that this species nests within the genus Artemisia.

Author: Walter Fertig, ASU Herbarium, 18 November 2013

Subshrubs, 30-60(-70) cm (aromatic). Stems erect to ± decumbent at bases, tomentose. Leaves mostly cauline; blades (20-90 mm) 1-pinnately lobed to 3-fid (proximal) or entire (distal), faces tomentose-canescent and gland-dotted. Heads (8-)10-30(-60) in paniculiform arrays (longer than wide). Involucres 4-4.5(-5) mm. Phyllaries 12-16, densely tomentose. Cypselae 1.5-2 mm (obscurely 10-ribbed, apices with thickened rims, faces gland-dotted).

Flowering Sep. Crevices in sandstone cliffs; 1900-2000 m; Utah.