Gymnema phuquocense (Apocynaceae, Asclepiadoideae), a new species from Vietnam

A new species of <i>Gymnema</i> from Vietnam - <i>G.phuquocense</i> - is described, illustrated, and compared with the similar <i>G.yunnanense</i>. <i>Gymnemaphuquocense</i> differs from <i>G.yunnanense</i> by the length of peduncle (3-4 mm vs. 10-13 mm), hairs on corolla lobe margin (absent vs. present), shape of seed (broadly ovate vs. ovate-oblong), shape of scale with 2 prominent longitudinal ridges on corolla tube (lanceolate vs. linear), and length of seeds (9-10 mm vs. 13-15 mm). A diagnostic key of the <i>Gymnema</i> species in Vietnam is also provided.