A rare plant in a few of our western counties. Our only reports are from Jasper and Vigo Counties. I have collected it in Benton, Newton and Spencer Counties. It is a typical prairie plant and is usually found in such a habitat. My Spencer County specimen, however, was found among large post oaks in a low, flat, post oak, pin oak, and swamp white oak flat about 4 miles northwest of Chrisney. This area is a low, flat woods about a half mile wide on the east side of Little Pigeon Creek. The soil is a hard, white, slightly acid clay in which are found several plants distinctly southwestern in their distribution.
Stems 6-15 dm, sparingly branched; lvs ovate-oblong, the lower to 2 dm, thrice pinnately compound, with narrowly oblong ultimate segments; upper lvs once or twice compound with linear segments 1-3 cm, the uppermost lvs often simple; rays 7-14; pet white; fr broadly ovate to suborbicular, 3-5 mm; 2n=40. Moist prairies and open woods; Mo., se. Kans., and n. Ark. to Ill., O., Ky., Tenn., and Ala. May, June. (Eulophus a.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.