Perennial herb, 20-60 cm high. Stems erect to ascending, simple or branched, glabrous. Leaves alternate, sessile, 10-60 x 0.5-1.5 mm, filiform to linear, acute,. Raceme dense. Bract 1.5-3 mm, linear to  linear-elliptic; pedicel 1-4.5 mm, erect. Calyx lobes 2.5-5 x 0.8-2 mm, elliptic to oblong, acute to obtuse, glabrous or hairy, margins narrowly scarious, white or tinged with reddish purple. Corolla 10-17 mm, yellow with violet nerves, glabrous externally. Spur 3.5-7 mm long. Capsule 3.5-7 mm, subglobose, glabrous. Seeds 2-3 mm, reniform-orbicular, blackish grey, winged, disc smooth.