Ambrosia hispida Pursh

Perennials, 10–50(–80+) cm. Stems prostrate or decumbent. Leaves mostly opposite; petioles 5–25 mm; blades rounded-deltate to ovate or elliptic, 20–35+ × 10–30+ mm, 2–3-pinnately lobed, bases cuneate, ultimate margins entire or toothed, abaxial and adaxial faces strigillose. Pistillate heads clustered, proximal to staminates; florets 1. Staminate heads: peduncles 1–2 mm; involucres obliquely cup-shaped, 2–3+ mm diam., strigillose; florets 5–20+. Burs: bodies ± pyriform, 1–2 mm, ± strigillose, spines or tubercles 0–5+, near middles or distal, stoutly conic, 0.1–0.5+ mm, tips straight. 2n = 104.