Silphium perfoliatum
Syst. Nat. ed. 10, 2: 1232. 1759.
Plants caulescent, 75–300 cm; fibrous rooted. Stems square, glabrous, hispid, or scabrous. Leaves: basal caducous; cauline usually opposite, rarely whorled (in 3s), petiolate or sessile; blades deltate, lanceolate, or ovate, 2–41 × 0.5–24 cm, bases attenuate or truncate (distal connate-perfoliate), margins entire, dentate, or bidentate, apices acuminate to acute, faces scabrous to hispid. Phyllaries 25–37 in 2–3 series, outer appressed, apices acute to acuminate, abaxial faces scabrous or hispid. Ray florets 17–35; corollas yellow. Disc florets 85–150 (–200); corollas yellow. Cypselae 8–12 × 5–9 mm; pappi 0.5–1.5 mm.
Distribution
Ont., Ala., Ark., Conn., Ill., Ind., Iowa, Kans., Ky., La., Mass., Mich., Minn., Miss., Mo., N.C., N.Dak., N.J., N.Y., Nebr., Ohio, Okla., Pa., S.Dak., Tenn., Tex., Va., Vt., W.Va., Wis.
Discussion
Varieties 2 (2 in flora).
Selected References
None.
Key
| 1 | Stems glabrous or sparsely scabrous; peduncles glabrous | Silphium perfoliatum var. connatum |
| 1 | Stems glabrous, hispid, or scabrous; peduncles usually scabrous to hispid | Silphium perfoliatum var. perfoliatum |