Annual 2-5 dm, usually simple below and with ascending, racemiform branches above, the pedicels to about 1 cm, or longer in fr; stem sparsely puberulent or scabrous below, otherwise glabrous; lvs narrow, alternate, 1-3 cm, sometimes with a pair of minute dark glands at base; sep 4.5-7 mm, short-awned, all glandular-toothed, deciduous as the fr matures; pet yellow, 10-17 mm; styles 5-9 mm, united to above the middle; fr ovoid, 4-5 mm, dehiscing through the essentially complete, non-ciliate false septa into 5 2-seeded segments, the members of a pair united at base by a triangular cartilaginous plate, the true septa not separating; 2n=30. Prairies and plains; Minn. to Mo. and Tex., w. to Alta., Colo., and N.M. Ours is var. rigidum. (Cathartolinum r.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
