Rhizomatous shrubs, subshrubs, or perennial herbs semiparasitic on the roots of a wide array of flowering plants. Leaves alternate, simple or trifoliolate, estipulate, entire, variously vestitured. Flowers axillary and single or in botryoid panicles, bisexual, zygomorphic, hypogynous with 5(4) purple, pink, or yellow showy, imbricate sepals and 5(4) petals, the 2 abaxial of which are reduced to glandular, lipid-secreting structures and the remaining 3(2) small and forming a flag inserted adaxially above the ovary. Stamens 4(3), 4-locular, curved, with stout filaments usually united basally, and anthers dehiscing by terminal pores; ovary superior, unilocular; carpels 2 but appearing singular due to the early abortion of one carpel; style stout, curved; stigma recessed; ovules 2, pendulous from the top of the ovary, anatropous, bitegmic. Fruits globose, nut-like, spiny capsules with the thin pericarp splitting irregularly, 1-seeded; seed large, lacking endosperm; cotyledons orbicular, ventrally flattened.One genus with 18 species, primarily in warm arid and semiarid areas of North, Central, and South America, and sporadically in the West Indies.