Cal-tube cupulate, with 4(5) lobes, the upper slightly the longer; cor-tube longer than the lips, straight, slightly widened distally, the upper lip straight, very concave, truncate across the narrow summit between the 2 short teeth, the lower lip about equaling the upper, 3-lobed, with 2 low ridges below the sinuses; stamens 4, paired, included, ascending under the upper lip; pollen-sacs acute at base; stigma entire; fr flattened, obliquely ovate, pointed, loculicidal; seeds normally 4, ellipsoid or oblong; hemiparasitic annuals with opposite lvs, the small fls borne in the upper axils. 25, N. Hemisphere.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
