Silphium integrifolium

Plants caulescent, 40-200 cm; fibrous rooted. Stems terete to slightly square, sparsely scabrous or glabrous (sometimes glaucous). Leaves: basal caducous; cauline opposite, sessile; blades lanceolate to ovate, 2-23 × 0.1-11 cm, bases round to caudate, margins finely serrate or entire, apices acute to acuminate, faces hispid, scabrous, or glabrous. Phyllaries 17-37 in 2-3 series, outer appressed, apices acute to acuminate, abaxial faces glabrous, hispid, pilose, or scabrous, sometimes stipitate-glandular. Ray florets 12-36; corollas yellow. Disc florets 70-225; corollas yellow. Cypselae 9-14 × 6-10 mm; pappi 1-4 mm.

Fibrous-rooted from a short rhizome or caudex; stems 5-15 dm; lvs firm, mostly opposite, seldom ternate or alternate, entire or toothed, ovate or lance- ovate to elliptic, mostly 7-15 נ2-6.5 cm, 2-4 times as long as wide, scabrous above, sessile and often clasping; heads relatively large and many-fld, with mostly 16-35 (commonly ca 21 or 34) rays 2-5 cm, the disk mostly 1.5-2.5 cm wide; 2n=14. Prairies and roadsides, less often in open woods; s. Mich. to Neb., s. to Ala., Miss., and Tex. 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.

©The New York Botanical Garden. All rights reserved. Used by permission.