Annuals, 8–45(–70) cm; not notably aromatic. Stems 1–5+, usually erect, sometimes ascending, simple or branched mostly distally, sometimes proximally (then ascending). Leaf blades 1560(–80) × 5–28 mm. Heads discoid, 1–15+, borne singly or in open, corymbiform arrays. Peduncles 1–56(–90) mm (glabrous or villosulous near heads, bracts 0–3, simple or 1-pinnate). Involucres 3.5–4.5 mm. Phyllaries 25–55+ in 3–4 series, margins erose. Receptacles 4.5–6.6 mm, rounded to obtuse or ± acute. Ray florets 0. Discs ovoid to hemispheric, 5.5–12.5 × 6–14 mm. Disc florets 400–750+; corollasgreenish yellow, 1.2–1.7 mm (sparsely glandular), lobes 4. Cypselae tan to brownish, obtriangular-obconic (angular, abaxial faces rounded, adaxial faces slightly convex), 1–1.5 mm, ribs white (2 abaxial, 2 lateral, each with reddish brown mucilage gland in distal 1/2, glands expanding into lobes, 1 adaxial, usually obscure, sometimes with a gland), faces not glandular; pappi coroniform, lobed (lobes 2, spreading, abaxio-lateral, ± obtuse to rounded). 2n = 18.
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