I have found this rare species on the dry, sandy spill bank of the Kankakee River west of the Teft Bridge in Jasper County, on a wooded ridge in Harrison County, in the Princeton fine sand in an open black and white oak woods 4 miles south of Vincennes, and on a slight rise in a post and pin oak woods in the "flats" about 4 miles northwest of Chrisney in Spencer County. It has also been collected in Lawrence County by Kriebel and in Porter County by Nieuwland.
Weedy annual; stems much branched, to 7 dm, minutely glandular- hairy, especially upwards; lvs 1.5-6 נ0.5-2.5 cm, oblong to elliptic or ovate, with ±evident lateral veins; pedicels 3-5 mm; cal 3-5 mm, 5-9 mm in fr, becoming inverted at maturity so that the 3 long teeth are lowermost; cor-tube about equaling the cal, the lobes 3-6 mm; filaments finally to 15 mm; nutlets glabrous, 1.5-3 mm; 2n=38. Dry soil, upland or sandy woods, and old fields; Me. to Mich. and Mo., s. to Fla. and Tex. Aug., Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.