Ambrosia cordifolia |
Ambrosia chamissonis |
|
---|---|---|
heartleaf bursage, Tucson bur ragweed, Tucson burr ragweed |
beach bur, beach bur-sage, cutleaf beach bur, silver beachweed, silver bur-ragweed, silver burr ragweed, silver burweed |
|
Habit | Shrubs, 30–50+ cm. | Perennials, 50–150(–350+) cm. |
Stems | erect. |
prostrate or decumbent. |
Leaves | mostly alternate; petioles 3–35 mm; blades deltate to rounded-deltate, 10–35(–80) × 10–30(–70) mm, bases cordate to truncate, margins coarsely toothed, abaxial faces densely puberulent (including veins), adaxial faces strigillose to scabrellous and gland-dotted. |
mostly alternate; petioles 15–30(–45+) mm; blades rounded-deltate to ovate or obovate, 20–45(–70+) × 10–25(–50+) mm overall, not lobed or 1–2(–3)-pinnately lobed, bases cuneate, ultimate margins entire or toothed, abaxial and adaxial faces strigillose to sericeous. |
Staminate heads | peduncles 0–1 mm; involucres cup-shaped, 2–3(–5) mm diam., strigillose; florets 8–30+. |
peduncles 0.5–2 mm; involucres shallowly cup-shaped, 4–6+ mm diam., strigillose; florets 8–25(–50). |
Pistillate heads | clustered, proximal to staminates; florets (1–)2. |
clustered, proximal to staminates; florets 1. |
Burs | bodies ± globose to fusiform, 3–4+ mm, tomentulose and stipitate-glandular, spines 8–20+, scattered, ± subulate (basally navicular), 1–2 mm, tips straight or uncinate. |
bodies fusiform to ± pyriform, 4–7+ mm, ± strigillose to pilosulous, spines 8–16+, scattered, stoutly conic or flattened- to triquetrous-subulate, 0.5–1.5+ mm, tips straight. |
2n | = 36. |
|
Ambrosia cordifolia |
Ambrosia chamissonis |
|
Phenology | Flowering Mar–Apr. | Flowering Apr–Nov. |
Habitat | Sandy washes, benches | Sandy beaches and strand |
Elevation | 700–1200 m (2300–3900 ft) | 0–10 m (0–0 ft) |
Distribution |
AZ; Mexico (Sinaloa, Sonora)
|
AK; CA; OR; WA; BC; Mexico (Baja California)
|
Source | FNA vol. 21, p. 14. | FNA vol. 21, p. 16. |
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Ambrosiinae > Ambrosia | Asteraceae > tribe Heliantheae > subtribe Ambrosiinae > Ambrosia |
Sibling taxa | ||
Synonyms | Franseria cordifolia | Franseria chamissonis, Franseria chamissonis subsp. bipinnatisecta, A. chamissonis var. bipinnatisecta |
Name authority | (A. Gray) W. W. Payne: J. Arnold Arbor. 45: 421. (1964) | (Lessing) Greene: Man. Bot. San Francisco, 188. (1894) |
Web links |
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