Silphium asteriscus

Plants caulescent, 30-200 cm; fibrous rooted. Stems terete, glabrous, hirsute, hispid, or scabrous. Leaves: basal persistent or caducous, petiolate or sessile; cauline alternate, opposite, or whorled, petiolate or sessile; blades simple, lanceolate, falcate, or ovate, 1.5-25 × 0.5-5 cm, bases attenuate to round, margins dentate, serrate, or entire, apices acuminate, acute, or obtuse, faces glabrous, hirsute, hispid, or scabrous. Phyllaries 12-26 in 2-3 series, outer appressed or reflexed, apices acute to acuminate, abaxial faces hispid or scabrous. Ray florets 8-21; corollas yellow. Disc florets 35-150; corollas yellow. Cypselae 6-15 × 4-11 mm; pappi 0-5 mm.

Fibrous-rooted from a short rhizome or caudex, 5-12 dm; herbage sparsely to densely spreading-hispid, or the lvs merely hispid-scabrous, many of the hairs of the stem ca 1 mm or more; stem leafy, the lvs opposite or alternate, coarsely toothed or entire, mostly 6-15 נ1.5-5 cm, (2-)2.5-5 times as long as wide, the lower often rather large and evidently long-petiolate, the others variously sessile or short-petiolate, rounded or tapering at base; heads several or many in a ±leafy-bracteate infl, with mostly ca 8 or ca 13(-21) rays 1.5-3 cm, the disk mostly 1-2 cm wide; 2n=14. Open woods, glades, and clearings; Va. to n. Fla., w. to Mo. and Tex. June-Sept. Our plants, with the stem lacking under- pubescence and with the receptacular bracts blunt and neither densely white-hairy nor glandular-hairy toward the tip, are var. asteriscus.

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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