Lysimachia maxima, a member of the Primulaceae (primrose) family, is a sprawling shrub with reddish brown bark. The leaves, borne in groups of three along the stems, are oval with the broadest portion at the tip of the leaves. The leaves are 3.8 to 8 cm (1.5 to 3 in) long and 1.8 to 5 cm (0.7 to 2 in) wide. The upper surface of the leaves has a few scattered hairs when young and the lower surface is sparsely covered with long, soft, rusty hairs when young. The corolla is purplish-yellow, bell-shaped, and about 10 to 12 mm (0.4 to 0.5 in) long.