Ambrosia dumosa

(A. Gray) W. W. Payne

J. Arnold Arbor. 45: 422. 1964

Common names: Bursage
Basionyms: Franseria dumosa A. Gray
Treatment appears in FNA Volume 21. Treatment on page 13. Mentioned on page 10, 12.
Shrubs, 10–40(–60+) cm. Stems erect. Leaves mostly alternate; petioles 2–8(–12+) mm; blades (white) ovate to elliptic, 10–25(–45) × 8–15(–30) mm, (1–)2–3-pinnately lobed, abaxial and adaxial faces densely strigillose. Pistillate heads intermixed with staminates (sometimes wanting or staminates sometimes wanting, plants unisexual); florets (1–)2. Staminate heads: peduncles 0–1(–2) mm; involucres shallowly cup-shaped, 3–5 mm diam., ± strigillose; florets 8–15+. Burs: bodies ± globose, 3–5+ mm, pilosulous and/or gland-dotted, spines 12–25+, scattered, ± subulate (± navicular at bases), 2–4 mm, tips straight. 2n = 36, 72, 108, 126.

Phenology: Flowering Mar–May(–Dec).
Habitat: Rocky or sandy washes, benches
Elevation: (-100–)100–1200(–1500) m

Distribution

V21-8-distribution-map.gif

Ariz., Calif., Nev., Utah, Mexico (Baja California, Sonora).

Discussion

References

None.

Lower Taxa

No lower taxa listed.