Stem to 1 m, branched above, pubescent around the upper nodes with minute stiffish hairs; basal and principal cauline lvs twice pinnate or ternate- pinnate, the lfls ovate to lanceolate, serrate to incised; umbels commonly 3-6 cm wide, at anthesis scarcely surpassing the lvs, the 8-16 rays subequal; fls pale yellow or cream-color; bractlets linear, acute, 1-4 mm; fr glabrous, ellipsoid, 4-6 mm, the lateral and some of the dorsal and intermediate ribs broadly winged; 2n=22. Woods and prairies; N.Y. and Ont. to Minn., s. to Fla. and Okla. May, June.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.