Heliantheae Cass.
Annual or perennial herbs or shrubs, not usually strongly scented, lacking latex. Lvs usually opposite, at least below, sometimes alternate. Involucral bracts in 1-few rows, at least the outer usually foliaceous. Receptacle usually with scales, rarely without. Capitula usually ⚥, rarely unisexual, sometimes homomorphic-discoid but usually heteromorphic with 1 row of ligulate ray florets and numerous actinomorphic disc florets. Anthers not tailed. Style branches each with 2 stigmatic lines. Achenes homomorphic or heteromorphic, with 0-10 ribs or 0-4 wings, terete or compressed; pappus of scales or awns (sometimes barbed), or reduced to a corona or 0.
Key
209 genera, c. 2500 spp., cosmopolitan, but mostly N., C. and northern S. America.
The Heliantheae is one of the largest and most diverse tribes in the Asteraceae. The treatment provided here follows Stuessy, T. F., in Heywood et al. (op. cit.). Stuessy accepted the dismemberment of polyphyletic Helenieae, given tribal status in many previous works; he included within the Heliantheae the subtribes Bahiinae and Gaillardiinae from the Helenieae.
Many Heliantheae are grown for their showy capitula and have established in the wild as escapes from cultivation. Other genera provide cosmopolitan weeds with barbed or spinous frs for dispersal. Characters of the involucral bracts and achenes are important in identification.
