Silphium brachiatum

Plants caulescent, 65-200 cm; fibrous rooted. Stems terete, glabrous. Leaves: basal caducous; cauline opposite, petiolate; blades lanceolate, hastate, ovate, or sagittate, 1-24 × 0.5-18 cm, bases cuneate, or round (distal), or cordate, truncate, hastate, or sagittate (proximal), margins coarsely dentate or entire, apices acuminate to acute, faces sparsely hirsute, hispid, or scabrous. Phyllaries 11-15 in 2-3 series, outer reflexed or appressed, apices acute, abaxial faces scabrous. Ray florets 7-9; corollas yellow. Disc florets 20-40; corollas yellow. Cypselae 7-8 × 5-6 mm; pappi 0.5-1 mm. 2n = 14.

Flowering late summer-fall. Open forests, calcareous soils, roadcuts; 200-600 m; Ala., Ga., Tenn.

Fibrous-rooted from a short rhizome or caudex; stem 10-15 dm, glabrous and glaucous; lvs opposite, narrowly ovate to triangular, coarsely toothed, mostly 13-25 נ5-10 cm, scabrous above, scabrous or hispid beneath, truncate or broadly rounded at base, or the lower cordate, on petioles 1.5-4.5 cm; heads rather numerous on slender peduncles in an open infl, relatively small, the disk ca 1 cm wide, with 4-6(-8) rays 1-1.5 cm; invol bracts glabrous except the ciliate margins; 2n=14. Woods in the Cumberland Plateau region; Ky. and Tenn. to Ala. and Ga. July-Sept.

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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