Ambrosia tomentosa

Nuttall

Gen. N. Amer. Pl. 2: 186. 1818

Endemic
Synonyms: Franseria discolor Nuttall Franseria tomentosa (Nuttall) A. Nelson
Treatment appears in FNA Volume 21. Treatment on page 17. Mentioned on page 11.

Perennials, 10–30+ cm. Stems erect. Leaves mostly alternate; petioles 8–25(–35+) mm; blades elliptic to lance-elliptic, 50–80(–180+) × 12–20(–50+) mm overall, (1–)2(–3)-pinnately lobed (lobes ± deltate), bases cuneate, ultimate margins with ± deltate teeth, abaxial faces densely finely scabrellous (silvery gray), adaxial faces strigillose. Pistillate heads clustered, proximal to staminates; florets (1–)2. Staminate heads: peduncles 2–9 mm; involucres saucer-shaped (with black nerves), 3–6+ mm diam., strigillose; florets 25–40+. Burs: bodies ± pyriform, somewhat flattened, 1.5–2.5(–4) mm, finely scabrellous, spines (1–)8–12+, scattered, stoutly conic, 0.5–1+ mm, tips straight.


Phenology: Flowering Jun–Sep.
Habitat: Seasonally wet clays or sands, disturbed sites
Elevation: (200–)1200–2100 m

Distribution

V21-19-distribution-map.gif

Ariz., Colo., Idaho, Ill., Iowa, Kans., Mo., Mont., Nebr., N.Mex., N.Dak., S.Dak., Tex., Utah, Wis., Wyo.

Discussion

Selected References

None.

Lower Taxa

None.

... more about "Ambrosia tomentosa"
John L. Strother +
Nuttall +
Ariz. +, Colo. +, Idaho +, Ill. +, Iowa +, Kans. +, Mo. +, Mont. +, Nebr. +, N.Mex. +, N.Dak. +, S.Dak. +, Tex. +, Utah +, Wis. +  and Wyo. +
(200–)1200–2100 m +
Seasonally wet clays or sands, disturbed sites +
Flowering Jun–Sep. +
Gen. N. Amer. Pl. +
Franseria discolor +  and Franseria tomentosa +
Ambrosia tomentosa +
Ambrosia +
species +