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.
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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

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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 +