Ambrosia cordifolia |
Ambrosia chenopodiifolia |
|
---|---|---|
heartleaf bursage, Tucson bur ragweed, Tucson burr ragweed |
San Diego bur ragweed, San Diego bur-sage, San Diego burr ragweed |
|
Habit | Shrubs, 30–50+ cm. | Shrubs, 30–80+ cm. |
Stems | erect. |
erect. |
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 5–20 mm; blades ovate to rounded-deltate, 20–35(–50) × 18–30(–45) mm, bases broadly cuneate to ± truncate, margins toothed, abaxial faces ± densely tomentulose (between veins), adaxial faces sparsely tomentulose, glabrescent. |
Staminate heads | peduncles 0–1 mm; involucres cup-shaped, 2–3(–5) mm diam., strigillose; florets 8–30+. |
peduncles 0–3 mm; involucres ± cup-shaped, 3–5 mm diam., tomentulose; florets 12–20+. |
Pistillate heads | clustered, proximal to staminates; florets (1–)2. |
clustered, proximal to staminates; florets 2(–3). |
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 obconic to fusiform, 4–6 mm, tomentulose (little, if at all, stipitate-glandular), spines 15–20+, scattered or on distal 1/2, ± subulate (the proximal basally flattened), 2–3 mm, tips usually uncinate, sometimes straight. |
2n | = 72. |
|
Ambrosia cordifolia |
Ambrosia chenopodiifolia |
|
Phenology | Flowering Mar–Apr. | Flowering Mar–Apr. |
Habitat | Sandy washes, benches | Clays or sandy soils, among lava rocks |
Elevation | 700–1200 m (2300–3900 ft) | 50–200 m (200–700 ft) |
Distribution |
AZ; Mexico (Sinaloa, Sonora)
|
CA; Mexico (Baja California, Baja California Sur)
|
Source | FNA vol. 21, p. 14. | FNA vol. 21, p. 14. |
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Ambrosiinae > Ambrosia | Asteraceae > tribe Heliantheae > subtribe Ambrosiinae > Ambrosia |
Sibling taxa | ||
Synonyms | Franseria cordifolia | Franseria chenopodiifolia |
Name authority | (A. Gray) W. W. Payne: J. Arnold Arbor. 45: 421. (1964) | (Bentham) W. W. Payne: J. Arnold Arbor. 45: 419. (1964) |
Web links |