Fls 5-merous, subsessile in dense, globose, head-like clusters; cal-lobes triangular-ovate, acute, generally a little shorter than the short-cylindric cor; cor- lobes triangular, 1-1.5 mm, shorter than the tube, acute, spreading; stigma slender, appearing as a continuation of its style, the two together longer than the ovary; fr globose, 1.5 mm, cupped by the withered cor, circumscissile near the base; seeds 4, scarcely 1 mm; 2n=14. Native of Europe, intr. throughout much of the U.S., parasitic chiefly on legumes.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.