Big Sagebrush

Often confused with Artemisia rothrockii, A. spiciformis has been recognized only recently as a widespread, high-elevation sagebrush of late-lying snowfields. Molecular analysis has not yet determined the degree to which this species intergrades with A. cana subsp. viscidula and A. tridentata subsp. vaseyana, the presumed parents of this putative hybrid. Because snow-field sagebrush produces fertile seeds and forms a stable community type, it is treated here as a distinct species.

Shrubs, 30–80 cm (widely branched, gray-tomentose), aromatic; root-sprouting. Stems relatively numerous, brown or grayish green. Leaves ± deciduous (by late summer, turning yellow); blades lanceolate, oblanceolate, or cuneate, 2.5–5.5 × 0.8–1.2+ cm, entire or irregularly 3–6-lobed (lobes to ¹/3 blade lengths, 1.5+ mm wide, rounded or acute; leaves of flowering stems usually smaller, entire), faces ± sericeous or tomentose. Heads (erect) in (leafy) paniculiform arrays 8–15(–25) × 0.5–3(–4) cm. Involucres ovoid or lanceoloid, (2.5–)4–6(–7) mm. Phyllaries lanceolate, sparsely to densely hairy. Florets 8–18(–27); corollas 2.5–3.5, glabrous. Cypselae 1–1.5 mm, glabrous or resinous. 2. = 18, 36, 54, 72.

Artemisia tridentata Nuttall subsp. spiciformis (Osterhout) Kartesz & Gandhi; Seriphidium spiciforme (Osterhout) Y. R. Ling

Artemisia spiciformis Osterhout, Bull. Torrey Club 27: 507 1900.
Artemisia spiciformis longiloba Osterhout, Muhlenbergia 4: 69. 1908.
A shrub, about 5 dm. high; bark grayish; leaves narrowly cuneate or oblanceolate, 2-3.5 cm. long, petioled, irregularly 3-5-toothed at the apex, or sometimes 3-fid with toothed diisions, cinerous-canescent ; heads comparatively few in a racemose inflorescence; involucre turbinate, 5-6 mm. high, 3-4 mm. broad; bracts about 15, imbricate in 4 series, somewhat floccose, one or two of the outer more or less foliaceous, lanceolate, acute, the rest ovate, acute, half as long as the innermost; inner bracts elliptic, scarious with a green midrib, obtuse or acutish; flowers about 12; corollas trumpet-shaped, nearly glabrous, fully 3 mm. long; style slightly exserted; achenes about 2 mm. long.
Type locality: North Park, Colorado. Distribution: Colorado and Utah.