Small-leaved Burr Medic, Plain Trefoil
Introduced annual forb, to 50cm tall or sprawling. Leaves alternating along the stems, compound, composed of 3 leaflets, each 0.2-1.2cm long, 2-13mm wide, flat, usually hairless on the upper surface, hairy below, margins toothed towards the tip, tips blunt with a small point. Flowers often small (less than 3mm across), pea-shaped, yellow, with 5 petals, 2 almost joined together. Flowers single or in pairs, the stalks arising at the bases of the leaves. Burrs hairy becoming sparsely hairy, with many hooked spines.
Description and photo (pages 403-404) and line drawing of burr (Fig. 51g page 403) in G.M. Cunningham, WE Mulham, PL Milthorpe and J H Leigh (1981 and later printings) Plants of Western New South Wales