Heads radiate, the rays 7–12, pistillate and fertile; invol bracts strongly imbricate, glutinous, shining, with stramineous base and abrupt green tip; receptacle flattish or convex, alveolate and sometimes also pubescent; disk-fls 10–50, functionally staminate, without an ovary, the style-branches short, slender, short-hairy, not stigmatic; achenes clavate, hairy; pappus of the disk-fls of 5(–8) long, white, spatulate scales united to half-length, that of the rays a minute, toothed crown or several short, ± concrescent scales; taprooted, glabrous annuals with alternate, narrow, entire, punctate lvs and numerous small yellow heads in a ± flat-topped infl. 2, N. Amer.
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