Perennials, 20-80 cm tall, glabrous except for inflorescences. Stems erect, often apically branched. Leaves usually numerous and alternate, rarely basal ones whorled, rarely all in whorls of 4; leaf blade linear, 2-8 X 0.2-1.5 cm, veins 1(-3). Inflorescences racemose, flowers crowded, axis elongating in fruit; axis and pedicels glabrous to densely with short glandular hairs; bracts linear to narrowly lanceolate, longer than pedicel. Pedicel 2-8 mm. Calyx glabrous or inside sparsely glandular hairy; lobes lanceolate to ovate-lanceolate. Corolla yellow, 1-1.5 cm (excluding spur); spur 1-1.5 cm, slightly curved; lateral lower lip lobes ovate-orbicular, 3-4 mm wide, middle lobe ligular; upper lip longer than lower lip, lobes ca. 2 mm, ovate. Capsule ovoid-globose. Seeds disclike, margin broadly winged, center verrucose when mature. Fl. Jun-Sep.