A short-lived herbaceous plant with weak stems growing up to 20 cm tall.Its slender stems are green and hairless or sparsely covered with sticky hairs. Its paired leaves (5-35 mm long and 5-30 mm wide) are kidney-shaped or broadly egg-shaped in outline. Its small white flowers are loosely clustered towards the tips of the branches. Its small capsules (1.5-2.5 mm long) are egg-shaped (i.e. ovoid) and contain a few reddish-brown seeds.