There were 8 species of the genus Asarum previously recorded in Vietnam, this paper reported Asarum yunnanense T. Sugaw., Ogisu and C.Y. Cheng as a species newly recorded for the flora of Vietnam. This species was collected from Na Hang Nature reserve, Tuyen Quang province. Asarum yunnanense is characterized by the following features: herbs, rhizomes vertical, height 20-30 cm, 3-5 mm in diam., internodes 2-3 cm. Leaves paired, 1-2
petiole 7-12 cm, villous
leaf blade adaxially deep geen with white speckles on veins, cordate-ovate, 9-11 x 16-18 cm, abaxial surface glabrous or pubescent on veins, adaxial surface sparsely hispid, base cordate, apex acute
cataphylls not seen. Peduncle declinate, 3.5 cm. Calyx slightly zygomorphic, purplish, campanulate
sepals connate beyond attachment to ovary, abaxially pilose, adaxially dark red pubescent
tube obconic
lobes spreading, triangular-orbicular. Stamens 12
filaments 0.3 mm, shoter than anthers
anthers 3 mm
connectives 0.8 mm, extended beyond anthers, subcylindric. Ovary inferior. Styles connate, short and thick, apex 6-cleft
stigmas white
stigmas terminal, radiating downward, decurrent. F1. Nov-Dec.