Silphium compositum

Plants scapiform, 50-250 cm; taprooted. Stems terete, glabrous (sometimes glaucous). Leaves: basal persistent, petiolate; cauline alternate, petiolate or sessile; blades cordate, deltate, elliptic, hastate, ovate, reniform, or sagittate, 2-35 × 0.5-52 cm, sometimes (proximal) pinnately or palmately lobed, bases oblique, truncate, attenuate, cordate, sagittate, or hastate, ultimate margins toothed, apices acute, faces glabrous, hispid, or scabrous. Phyllaries 11-18 in 2-3 series, outer appressed to reflexed, apices obtuse to cuspidate, abaxial faces sparsely scabrous. Ray florets 6-12; corollas yellow. Disc florets 20-85; corollas yellow. Cypselae 6-12 × 4-10 mm; pappi 1-4 mm. 2n = 14.

Flowering summer-early fall. Open, pine and oak forests, sandy soils, fields, roadsides, meadows; 0-1600 m; Ala., Fla., Ga., N.C., S.C., Tenn., Va., W.Va.

Much like no. 8 [Silphium terebinthinaceum Jacq.], but with smaller and often more numerous heads, the disk 0.8-1.5 cm wide, the invol 6-11 mm, the rays 5-10, 1-2 cm; lvs often wider than long, variously merely toothed to deeply pinnatifid or palmatifid and again lobed or cleft; 2n=14. Dry, often sandy places, esp. in pine woods; Va. to Fla., w. to Tenn. and Ala. June-Sept. (S. lapsuum; S. orae; S. reniforme; S. venosum)

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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