A new species of Capparis (Capparaceae) from Bac Kan Province, Vietnam (Effectively published online: 17 October 2025)

Capparis rupicola (Capparaceae), a new species from limestone cliffs of the Bac Kan Province, northern Vietnam, is described and illustrated. The new species is a shrub characterized by pendulous branches, glabrous twigs with cataphylls at the base, wanting or vestigial stipular thorns, coriaceous, obovate leaves, serial flowers in supra-axillary rows, glabrous sepals and petals, and an ellipsoid, ribbed ovary with a knob-shaped stigma. The habit, as well as the ecological adaptations to rocky habitats, appear peculiar if compared to other species of Capparis known from south eastern Asia. The new species is related to C. micracantha subsp. micracantha, a taxon widespread from India eastwards to Indonesia and the Philippines, which is a small tree or an erect shrub, rarely a climber, differing in the twigs pubescent or puberulous, stipular thorns well developed, serial flowers in higher number, pedicels pubescent, sepals pubescent at the margins and shorter filaments. The affinities of the new species with related taxa are discussed and a key is provided for all the species of Capparis with serial flowers reported from Vietnam. The conservation status is provisionally assessed as Vulnerable (VU D2).