17. Rudbeckia grandiflora (Sweet) C. C. Gmelin ex de Candolle in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 556. 1836.
Largeflower or rough coneflower
Centrocarpha grandiflora Sweet, Brit. Fl. Gard., ser. 2, 1: plate 87. 1831
Perennials, to 120 cm (roots fibrous, caudices often woody). Stems proximally glabrous or sparsely hairy (hairs spreading), distally strigose (hairs ascending). Leaves: blades elliptic, lanceolate, or ovate (± conduplicate, not lobed), bases cuneate to rounded, margins entire or remotely serrate, apices acute, faces strigose, abaxially gland-dotted; basal petiolate, 10–35 × 2–11 cm; cauline petiolate (proximal) to nearly sessile (distal), 4–30 × 1.5–9 cm. Heads mostly borne singly. Phyllaries to 15 mm (strigose and gland-dotted). Receptacles hemispheric to ovoid; paleae 5–6.5 mm, (apical margins glabrous) acuminate-cuspidate, awn-tipped, abaxial tips sparsely strigose. Ray florets 12–25; laminae elliptic to obovate (reflexed), 20–50 × 5–10 mm, abaxially hairy and gland-dotted. Discs 10–30 × 15–25 mm. Disc florets 200–800+; corollas greenish yellow basally and in lobes, otherwise maroon, 3.5–5 mm; style branches ca. 1.8 mm, apices obtuse. Cypselae 2–3 mm; pappi coroniform, to 0.5 mm.
Varieties 2 (2 in the flora): mostly c, e, and s United States.