Stem stout, much branched at the base, glabrous, obscurely angled in the thinner branches. Leaves linear-lanceolate, sessile, scabrid on both surfaces, acute or subacute above, rounded below, upwards of 1 in. long, 1 1/2 lin. broad. Flowers solitary or 2 together in small cymes arising singly from the nodes. Calyx-teeth linear, scabrid; the upper 5 lin. long, 1/2 lin. broad, the others 4 lin. long. Corolla-tube 4–5 lin. long, somewhat pubescent outside; upper lip 3 lin., lower 4 lin. long, with 2 yellow marks on the palate. Stamens nearly equal; filaments of the lower pair sparingly hairy. Ovary pubescent. Capsule somewhat pubescent, 4–5 lin. long, containing 35–40 seeds.