Gray's Feverfew

Biennials (sometimes flowering first year or persisting), 10–30(–60+) cm. Leaf blades ovate or rounded-deltate to elliptic, 30–80(–120+) × 10–20(–40+) mm, usually ± pinnately or sub-bipinnately lobed, ultimate margins entire, faces strigillose, usually also with erect hairs 1–2 mm and gland-dotted. Heads disciform or obscurely radiate, borne in open, ± paniculiform arrays. Peduncles 2–8(–12+) mm. Phyllaries: outer 5 lance-ovate to elliptic, 2.5–3+ mm, inner 5 ± orbiculate, 3–3.5 mm. Pistillate florets 5; corolla laminae 0 or ± coroniform, 0.1–0.5 mm. Disc florets 20–30+. Cypselae ± obovoid, 2–3 mm; pappus-like enations 2, ± erect, deltate to ovate, 0.5–1 mm (sometimes a third, subulate spur near apex adaxially). 2n = 36, 68, 72.

Parthenium confertum var. divaricatum Rollins; P. confertum var. lyratum (A. Gray) Rollins; P. confertum var. microcephalum Rollins