Ambrosia eriocentra

(A. Gray) W. W. Payne

J. Arnold Arbor. 45: 423. 1964.

Basionym: Franseria eriocentra A. Gray Proc. Amer. Acad. Arts 7: 355. 1868
Treatment appears in FNA Volume 21. Treatment on page 13. Mentioned on page 10, 11.

Shrubs, 30–80(–120+) cm. Stems erect. Leaves mostly alternate; petioles 0–2 mm; blades (± white abaxially) elliptic, lance-linear, or rhombic, 10–40(–60) × 5–15(–40) mm, bases ± cuneate, margins irregularly toothed to ± laciniate, abaxial faces densely strigillose, adaxial faces tomentulose and pilosulous. Pistillate heads clustered, proximal to staminates; florets 1. Staminate heads: peduncles 0–0.5 mm; involucres saucer-shaped to shallowly cup-shaped, 4–8+ mm diam., tomentulose and/or pilose; florets 12–25+. Burs: bodies obconic to fusiform, 3–5+ mm, densely villous and stipitate-glandular, spines 12–20+, scattered or mostly distal, ± subulate, 3–4 mm, tips straight. 2n = 36.

Phenology: Flowering Apr–May(–Jul).
Habitat: Sandy and gravelly washes
Elevation: 700–1700 m



Ariz., Calif., Nev., Utah.


Selected References


Lower Taxa