42. Artemisia palmeri A. Gray, Proc. Amer. Acad. Arts. 11: 79. 1876.
Artemisiastrum palmeri (A. Gray) Rydberg
Subshrubs, 100–350 cm, mildly aromatic. Stems usually 1–15, erect, brown, simple (wandlike, brittle, bases woody), glabrous. Leaves cauline (petiolate), bicolor (gray-green and dark green); blades broadly lanceolate, 3.5–12(–15) × 0.2–10 cm, relatively deeply and coarsely pinnately lobed (lobes 3–7+), faces canescent (abaxial) or glabrous or sparsely hairy (adaxial). Heads (erect or nodding, peduncles relatively slender) in open, paniculiform arrays, 15–40 × 3–10 cm (widely branched). Involucres globose, 2.5–3.5 × 2–5 mm. Phyllaries (pale green to stramineous) broadly ovate, glabrous or sparsely hairy (receptacles paleate). Florets: pistillate 0; bisexual 8–30; corollas pale yellow, 1.5–2.2 mm, resinous-glandular (style branches exsert, truncate, erose). Cypselae (light brown, shiny) ellipsoid, 1–1.2 mm, (4-angled), glabrous or glandular. 2n = 18.
Flowering early–mid summer. Ravines, coastal areas, sandy soils; of conservation concern; 100–300 m; Calif.; Mexico (Baja California).
Artemisia palmeri is known only from drainages near the coast, from northeast of San Diego to just south of Ensenada. Most of its habitat has been destroyed by urban development. It is of particular interest because of its paleate receptacles, an anomalous trait that confounds our understanding of its evolutionary relationship to other species of Artemisia.