The genus Didymocarpus Wall. comprises about 180 species, mainly distributed Southeast Asia, there were 3 Didymocarpus species recorded in Vietnam. During the study of specimens of Gesneriaceae collected in Vietnam, we found species Didymocarpus kerrii Craib in Ba Vi National Park, Vietnam. Didymocarpus kerrii is herbs, have or near stemless. Leaves basal or opposite if have stem. leaf blade near round or broadly elliptic, ca. 1-4.5 x 1-4 cm, papery, pubescent in 2 surfaces especially gladuland hair in abaxial surface, and then glabrous, margins serrate, lateral veins 5-6 pairs
petiole 0.5-5 cm long. Inflorescences cymes, multi-flower
peduncle with puberulent, and then glarous
Calyx connate into campanulate, 5 mm long, 2 lips. Corolla 20 mm long, outer glabrous, 2 lips: adaxial lip 2 lobes
abaxial lip 3 lobes, longer than adaxial lip, round apex. Stamens 2, coherent at the anther
Filament 2 mm long, adnate in middle of corolla, glabrous
ovary 10 mm long, glabrous
style 3-4 mm long
stigma head. Capsule line, straight, ca. 3-4 cm long, glabrous. Seeds unappendaged. This species is closed to D. pulcher but differs from the later by having corolla outcr glabrous
leaf blade near round or broadlly elliptic, ca. 1-4,5 x 1-4 cm. Voucher specimens were collectcd in Ba Vi National Park, Hanoi and deposited in the Herbarium of the Institute of Ecology and Biological Resources, Hanoi, Vietnam (HN).