Rudbeckia hirta L.

  • Authority

    Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

  • Family


  • Scientific Name

    Rudbeckia hirta L.

  • Description

    Species Description - Biennial or short-lived perennial 3–10 dm, ± hispid or hirsute throughout; lvs variable, the lower mostly oblanceolate to elliptic and long-petiolate, the others lance-linear to oblong or ovate, mostly sessile; heads mostly long-pedunculate, the hemispheric or ovoid disk 12–20 mm wide, dark purple or brown (yellow); invol bracts copiously hirsute or hispid, sometimes much elongate; rays 8–21, orange or orange-yellow, sometimes darker or marked with purple at base, 2–4 cm; receptacular bracts acute, ± hispid or hispidulous near the tip; style-appendages elongate, subulate; pappus none; 2n=38. Various habitats; Nf. to Fla., w. to B.C. and Mex. June–Oct. Var. hirta occurs mostly in relatively undisturbed habitats in the mts. from Pa. to Ga. and Ala., and sparingly n. to Me. and w. to Ill.; it has coarsely toothed lvs, the basal ones with the blade 2.5–7 cm wide and about twice as long, the cauline ones lance-ovate to ovate or pandurate. Var. pulcherrima Farw. (R. serotina) is widespread especially in disturbed habitats; it has entire or finely toothed lvs, the basal ones with lanceolate or oblanceolate blade 1–2.5(–5) cm wide and (3–)4–5 times as long, the cauline ones spatulate or oblanceolate to broadly linear.

  • Common Names

    black-eyed Susan