Stout, to 1.5 m, glabrous below and at base of the rays, usually scaberulous below the umbellets; lower lvs 1-3 dm, the upper much reduced, with broad sheathing petioles; lfls lanceolate to oblong, 3-8 cm, acuminate, coarsely toothed, the margin minutely ciliate and not differentiated; umbels 6-15 cm wide; rays 13-25, the outer spreading but not decurved; fr oblong- elliptic, 4-7 mm, cordate at base, glabrous, the lateral ribs prominently winged; oil-tubes few; seed adherent to the pericarp; 2n=22. Mt. woods; Pa. to N.C. and Tenn. July-Sept. (A. curtisii)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.