Abstract
The Indochinese Peninsula is a main center of speciation of Capparis, but the taxonomic treatment of the genus is still critical in this area. With regard to Vietnam, a discordant number of species was recorded by different authors during the last century, whereas various new species have been recently described. An updated checklist of the intrageneric taxa occurring in the country is here presented, including a new species from the island of Hon Tre, Khanh Hoa Province. The genus comprises in Vietnam 37 species, 9 subspecies and 3 varieties, all belonging to Capparis sect. Monostichocalyx. The study area, with 10 endemic species, is confirmed as one of the hotspots of the genus. Three lectotypes are also selected. The new species here described and illustrated, C. oxycarpa, is related to C. pranensis, differing in the few-flowered subumbels, narrower sepals, smaller petals, longer filaments and smaller, apiculate fruit; its affinities with related taxa and conservation status are discussed, and data on its ecology and phenology are given.