Heads radiate or seldom discoid, the rays pistillate and fertile, white or sometimes yellow or anthocyanic; invol bracts ±imbricate in 2-4 series, dry, at least the margins and tips scarious or hyaline, the midrib sometimes greenish; receptacle flat or convex, naked; disk-fls tubular and perfect, the cor with (4)5 lobes; style-branches flattened, truncate, penicillate; achenes subterete or angular, 5-10-ribbed, or those of the rays with 2-3 wing-angles; pappus a short crown, or none; herbs or seldom shrubs with alternate, entire or toothed to occasionally pinnatifid lvs and hemispheric or depressed- hemispheric heads. 100, N. Hemisphere, espec. Old World.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
