Silphium perfoliatum L.
Family: Asteraceae
cup plant,  more...
Silphium perfoliatum image

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.

Stems 1-2.5 m, square; lvs or their petiolar bases connate- perfoliate, the blade deltoid to ovate, coarsely toothed, to 3 נ1.5 dm; heads in an open infl, the disk 1.5-2.5 cm wide; invol 12-25 mm, its bracts elliptic or ovate, subequal or the outer longer, rays 1.5-4 cm; 2n=14. Woods and low ground; s. Ont. to N.D., s. to N.C., Miss., La., and Okla., and intr. into N. Engl. July-Sept. Two vars.

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

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Silphium perfoliatum image
Silphium perfoliatum image
Silphium perfoliatum image
John Hilty  
Silphium perfoliatum image
John Hilty  
Silphium perfoliatum image
John Hilty  
Silphium perfoliatum image
Silphium perfoliatum image
Silphium perfoliatum image
Steve Hurst