Annual to short-lived much-branched herbaceous perennial; semi-erect, mostly 30-75 cm (rarely -1.4 m), sometimes prostrate . Stems fine, green, differing from S. humilis in having only fine white hairs down one side, but no bristles as in S. humilis . Leaves trifoliolate, the central leaflet from 16-26 mm long and 3-6 mm wide, acute. Inflorescence an axillary or terminal oblong spike, to 20 mm long, with 8-14 yellow papilionaceous flowers with standard 4-5 mm wide. 2-segmented pod, both segments usually fertile; the upper segment 6-7 mm long (including recurved beak or hook 3-4 mm long), and the lower segment 3.5 mm long. A distinct type (a tetraploid) with shorter beak on the pod occurs in southern Florida. Seeds tan to dark maroon, mottled, 2-2.5 mm long, unsymmetrically kidney-shaped. 270,000 seeds-in-pod and 450,000 dehulled seeds/kg.