Striga

Annual or rarely perennial herbs, hemiparasitic or holoparasitic on roots, sometimes drying dark, usually scabrid; stems simple or branched, rarely tufted, erect, sometimes rigid, usually quadrangular, often ridged. Leaves opposite or upper ones alternate, sessile or subsessile, usually erect, often scale-like especially near stem base, sometimes throughout, otherwise usually narrow, entire, rarely dentate, usually scabrid. Flowers solitary in axils of upper leaves or bracts, spicate, sometimes dense and/or elongating in fruit. Bracts leaf-like or reduced; bracteoles 2. Calyx tubular, 5-cleft or 5-dentate, 5-15-ribbed; tube cylindrical to campanulate; lobes sometimes unequal, usually erect, sometimes with membranous margins. Corolla tubular, usually bilabiate and glandular, 5(4)-lobed; tube narrowly cylindrical, rather sharply bent at or above middle and often dilated there, mouth small, bearded; limb expanded; upper lip erect or recurved, entire (lobes fused), emarginate or bifid, interior in bud; lower lip 3-lobed, usually longer than upper one, spreading. Stamens 4, didynamous, arising in upper part of corolla tube, included; filaments linear, short, sometimes shorter than the unithecate, basifixed, erect anthers. Nectary present at base of ovary. Ovary bilocular, elongated, ellipsoid or ovate; ovules many; style linear or terete, included, usually persistent; stigma somewhat thickened or clavate, sometimes bifid. Fruit a cylindrical or subovoid, loculicidal capsule, enclosed in calyx. Seeds minute, obovoid or oblong, with prominent encircling ridges; testa reticulate, membranous. x = 10 (11, 12) (high polyploidy).