Barrel Medic, Snail Medic, Caltrop Medic
Introduced annual forb, prostrate or ascending with branches to 50cm long. Leaves alternating along the stems, compound, with 3 leaflets, each 0.6-2.5cm long, 5-20mm wide, flat, upper surface sparsely hairy, lower surface hairy, edges toothed, and with blunt tips. Flowers yellow, pea-shaped, with 5 petals, 2 almost joined together. Flowers in clusters of 1-4, the stalks arising from the bases of the leaves. Burr sparsely hairy, with many straight to curved spines.
Description (as Medicago truncatulata var. truncatulata) (page 405) and line drawing of burr (Fig. 51i page 403) in G.M. Cunningham, WE Mulham, PL Milthorpe and J H Leigh (1981 and later printings) Plants of Western New South Wales