Ambrosia confertiflora
in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 526. 1836.
Perennials, 20–80 (–150+) cm. Stems erect. Leaves mostly alternate; petioles 10–35 mm; blades lanceolate to ovate, 40–85 (–150) × 20–35 (–55) mm overall, laciniately 2–4-pinnately lobed (lobes ± lanceolate); bases cuneate to truncate, ultimate margins entire, abaxial and adaxial faces strigillose to sericeous (often grayish) and glanddotted. Pistillate heads clustered, proximal to staminates; florets 1 (–2). Staminate heads: peduncles 0.5–2 mm; involucres cupshaped, 1.5–3+ mm diam., strigillose; florets 5–20+. Burs: bodies pyramidal to pyriform, 1–2 mm, strigillose to pilosulous, spines (1–) 5–12+, mostly distal, stoutly conic to subulate, 0.5–1 mm, tips uncinate. 2n = 72, 108.
Phenology: Flowering (May–)Sep–Dec.
Habitat: Waste places, disturbed sites
Elevation: 10–2000 m
Distribution
Ariz., Calif., Colo., Kans., N.Mex., Okla., Tenn., Tex., Utah, Mexico
Discussion
Selected References
None.
Lower Taxa
"strigillose" is not a number. "pilosulous" is not a number.