Stems annual, suberect, under a foot high, slender, striated, slightly pilose. Stipules small, lanceolate acuminate. Petioles an inch long, subglabrous; leaflets 3, central one linear-lanceolate, 1–1 1/2 in. long, 2 lines broad, narrowed gradually from near the base to the apex, the petiolule very short, lateral ones equal-sided, under surface thinly adpressed grey-silky. Flowers 2–4, on peduncles which exceed the petioles. Bracts small, linear. Pedicels a line long; bracteoles blunt and very minute. Calyx campanulate, 2 lines deep, subglabrous, the teeth lanceolate, reaching half down, the upper two connate. Corolla rose-red, more than twice as long as the calyx; keel truncate. Pod terete, 1 1/2 in. long, 2 lines thick, densely ferruginous-bristly, 6–8-seeded.
