Plants annual or perennial, bristly or pubescent. Roots frequently containing purple dye. Stems erect or prostrate. Leaves alternate. Cymes bracteate. Flowers often heterostylous. Calyx 5-parted to base, slightly enlarged, base sometimes hardened. Corolla funnelform, usually with hairs outside; tube straight or slightly curved; throat unappendaged; limb usually shorter than tube; lobes spreading. Ovary 4-lobed. Style 2-or 4-branched, each branch terminated with 1 stigma. Gynobase flat. Long-styled flowers with included stamens inserted at middle of corolla tube; style long, slightly exserted. Short-styled flowers with stamens inserted at throat; style shorter, reaching to middle of corolla tube. Nutlets oblique-ovate, tuberculate, adaxially flat or slightly concave; attachment scar at base.
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