Euphrosyne ambrosiifolia A. Gray, Smithsonian Contr. Knowl. 3(5): 102. 1852 (as ambrosiaefolia); Cyclachaena ambrosiifolia (A. Gray) Rydberg; Iva ambrosiifolia (A. Gray) A. Gray

Leaves: petioles 5–12(–45) mm; blades 3–5(–9) × 4–5(–8) cm overall, lobes 1–3 mm wide. Peduncles 3–12+ mm. Involucres 2–3+ mm. Phyllaries: outer 5 sparsely strigose or glabrous. Paleae 1–1.5 mm. Functionally staminate florets: corollas 1.5–2 mm. Cypselae 1.4–1.7 mm. 2n = 36.

Flowering Jul–Sep. Disturbed sites (roadsides, washes, etc.), in sandy, gypseous, or calcareous soils; 1000–2000 m; Ariz., N.Mex., Tex.; Mexico (Chihuahua, Coahuila, Durango, Nuevo León, San Luis Potosí, Sonora, Zacatecas).