Lysimachia iniki is a woody shrub, in the Primulaceae (primrose) family, with pendulous branches 30 to 150 cm (11.8 to 59 in) long that are green and densely hirsute. Leaves are alternate, obovate to orbicular, 1 to 10 mm (0.1 to 0.4 in) apart, sessile (without a stalk), cupped upward, 3.5 to 5.4 cm (1.4 to 2.2 in) long, 2.5 to 4.2 cm (1.0 to 1.7 in) wide, and with a rounded tip that becomes abruptly acuminate (tapered concavely). Secondary and tertiary veins of the leaves are prominent and allow light to shine through them. Flowers are 6 to 7 borne solitary in the leaf axils, shaped like a funnel, with petals white at the tip and dark red at the base. Capsules are globose, 6 to 7 mm (0.24 to 0.28 in) long, and seeds are dark brown and irregularly shaped.