Prostrate or scrambling annual; stems to 2 m long when through other vegetation, rather stout, branched, densely clothed in retrorse, hooked, scabrid hairs on the sharply acute angles. Lvs and stipules in whorls of 5-8, sessile, 10-60 × 2-8 mm (sometimes smaller on exposed prostrate shoots), linear-oblanceolate or narrow-elliptic, often spathulate or obovate on exposed lateral shoots; margins flat or nearly so, densely clothed in retrorse, hooked, scabrid hairs; midrib below and surface generally above ± scabrid; apex shortly awned. Fls (1)-2-(6), in axillary divaricating cymes; peduncles usually > pedicels; whorl of bracts at base of pedicels leaflike and scabrid. Corolla 1-2 mm diam., white or whitish; lobes ovate, ± mucronate. Mericarps 2.5-4 mm diam. (excluding bristles), globose or subglobose (often 1 of the pair smaller or abortive), densely furnished with hooked bristles.