Monographs Details: Rudbeckia
Authority: Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Description:Genus Description - Heads radiate, the rays mostly 5–21, neutral, yellow or orange to sometimes anthocyanic, or rarely absent and the heads discoid; invol of subequal or irregularly unequal, green and ± herbaceous, mostly spreading or reflexed bracts in 2–3 series; receptacle enlarged, conic or columnar, chaffy, its bracts partly enfolding the achenes, not spinescent, but sometimes awn-pointed; disk-fls perfect and fertile, narrowed to a ± distinct tube at base; style- branches flattened, with very short and blunt or elongate and acuminate, externally hairy appendage, without well marked stigmatic lines; achenes ± quadrangular, glabrous; pappus a short crown, or none; herbs with alternate, entire to pinnatifid lvs. 16, mainly U.S.