Mertensia Roth

Herbs perennial, glabrous or pubescent, with thin rhizomes. Basal leaves usually withering early, ovate; stem leaves alternate. Cymes terminal, several flowered, becoming racemelike, ebracteate. Flowers pedicellate. Calyx 5-cleft or 5-parted, shorter than corolla tube; lobes lanceolate to ovate, not changing much in fruit. Corolla funnelform, usually sky blue or blue; throat with transverse folds or scalelike appendages; lobes spreading, ovate to oblong or semiorbicular, apex obtuse. Stamens inserted between appendages or slightly below; filaments short, filiform or ligulate; anthers oblong to ovate, longer than filaments, exserted. Ovary 4-parted. Style filiform, exserted from corolla. Gynobase conical. Nutlets tetrahedral, glabrous; adaxially sharp, sometimes nearly winged on keel; abaxially convex, wrinkled, tuberculate, rarely narrowly winged along margin; attachment scar at base adaxially.