37. Artemisia ludoviciana Nuttall, Gen. N. Amer. Pl. 2: 143. 1818.
Silver wormwood, white or silver sage
Artemisia vulgaris Linnaeus var. ludoviciana (Nuttall) Kuntze
Perennials, 20–80 (rarely to 120 in desert washes) cm, aromatic (rhizomatous). Stems relatively few to relatively numerous, erect, gray-green, simple or widely branched, hairy. Leaves cauline, uniformly gray-green, green, or white, or bicolor (white and green); blades linear to broadly elliptic, 1.5–11 × 0.5–4 cm, entire or lobed to relatively deeply pinnatifid, faces hairy. Heads (erect to nodding, peduncles 0 or 2–5 mm) in congested to open (widely branched) arrays. Involucres campanulate or turbinate, (1–)2–4(–5) × 2–5(–8) mm. Phyllaries (gray-green), lanceolate to ovate or obovate (margins narrowly hyaline), densely tomentose. Florets: pistillate 5–12; bisexual 6–45; corollas yellow, sometimes red-tinged, 1.5–2.8 mm, glabrous. Cypselae ellipsoid ca. 0.5 mm, (obscurely nerved) glabrous. 2n = 18, 36, 54.
Subspecies ca. 7 (6 in the flora): North America, Mexico.