in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 592. 1836.
Subshrubs or shrubs [trees], to 100(–200)[–500+] cm. Stems erect, branched from bases or ± throughout. Leaves cauline; alternate; petiolate [nearly sessile]; blades pinnately nerved, mostly elliptic to lance-oblong or ovate, bases rounded to cuneate, margins entire [toothed], faces glabrous or ± scabrellous, usually gland-dotted and vernicose. Heads discoid or radiate, borne ± singly or in ± spiciform arrays. Involucres campanulate to hemispheric, 4–20 mm diam. Phyllaries persistent, 12–40 in 2–4+ series (subequal or unequal, outer longer). Receptacles flat to conic-ovoid, paleate (paleae conduplicate, cartilaginous to scarious). Ray florets 0 or [5–]13–21, either neuter, or styliferous and sterile; corollas yellow. Disc florets 10–50[–150], bisexual, fertile; corollas yellow, tubes much shorter than cylindric-funnelform throats, lobes 5, ± deltate. Cypselae ± compressed or flattened [subterete], oblong to oblanceolate (not winged, ± sericeous); pappi persistent or tardily falling, of 2 subulate scales. x = 9.
sw United States, Mexico, Central America, South America.
Species ca. 30 (2 in the flora).