Cal membranous, reticulate-veiny, shallowly 4-lobed, more deeply cleft above and below than on the sides, in fr strongly accrescent and becoming suborbicular; cor very irregular, the upper lip very concave, with a lateral lobe-appendage on each side near the summit, the lower lip 3-lobed, the throat with 2 longitudinal ridges; stamens 4, paired, ascending under the upper lip; stigma capitate; fr flat, suborbicular, loculicidal; seeds large, flat, narrowly winged; hemiparasitic annuals with opposite, sessile or subsessile, serrate, pinnately veined lvs and rather small yellow fls sessile or subsessile in the axils of the uppermost or bracteal lvs, forming a secund leafy spike. 2-several, temperate Eurasia and N. Amer.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
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