Leptomischus hiepii, a new species of Rubiaceae from Vietnam

Leptomischus hiepii, a new species of the tribe Argostemmateae from Son La province, northwestern Vietnam, is described and illustrated. Morphologically it allies to L. wallichii, L. erianthus and L. funingensis by sharing a similar habit, large stipules and similar corolla shape, but it differs by its anisophyllous leaves, 1-flowered inflorescences, homostylous flowers and tubular-campanulate corollas.