Annual herb, erect with spreading to ascending branches, up to 60 cm high; indumentum of curved hairs only. Leaves ± sessile, linear, 10–70 mm long, 0.5–2.5 (–4.0) mm wide; apex acute, mucro c. 0.2 mm long. Inflorescence supra-axillary or rarely leaf-opposed, a raceme to 200 mm long, exceeding the leaves. Pedicel to 4.5 mm long. Alae sometimes perpendicular, mostly deflexed becoming reflexed in fruit (position), herbaceous, lanceolate, narrowly elliptic and oblanceolate, often dimidiate to falcate, 4.3–6.3 mm long, 1.0–2.6 mm wide, with minute appressed hairs. Corolla purple; floral appendages spathulate; upper petal claw 1 mm wide. Stamens terminate at stigma, monadelphous; staminal flap