The leaves are single leaf opposite, clustered at the base, linear lanceolate or linear, 3 to 9 cm long and 1 to 4 cm wide. The base of the leaves embraces the stem, and the leaves are entire. The leaves have short villi on both sides, and there are many villi on the leaf margin.
The leaves are oval, 5 to 12 cm long and 2.5 to 4 cm wide. The top of the leaves is gradually sharp, and the base is blunt or sharp.
The flowers are solitary in the axils of the leaves, the petioles are 6 to 24 mm long, the calyx is tubular, green or purple, the petals are 5, white, light pink or light yellow, in strips.
The inflorescence is terminal or axillary. It is composed of 2 to 8 cymes. The Corolla is pink or purplish, 2.5 to 3 cm long.
