ABSTRACT
The paper provides an identification key and an annotated list of all six species of the genus Ridsdalea J.T.Pereira & K.M.Wong (Rubiaceae, Gardenieae) recorded in the flora of Vietnam, along with data on their valid names, synonyms, types, and distribution. A new species, R.backanensis, discovered in the limestone area of Bac Kan Province (northern Vietnam), is described and illustrated. Detailed data on its characters, ecology, distribution, phenology, preliminary IUCN conservation status, and taxonomical notes are given. The newly discovered species is potentially interesting for cultivation as an ornamental tree that may be effectively used in garden and urban green architecture.
ABSTRACT
Raphiocarpustaygiangensis, a new species of Gesneriaceae family discovered in Tay Giang District, Quang Nam Province, Central Vietnam, is here described and illustrated. The new species is diagnosed by the combination of its stem up to 2 m long, sericeous hairs on young stem, leaf petiole and adaxial mid-vein, sparsely and minutely serrate leaf margin, axillary inflorescence spreading along stem, sparsely long gland-tipped hairs on peduncle, pedicel, calyx, outside corolla and pistil, calyx 5-disparted from base, purplish white flower with purple stripes inside corolla tube, and dish-shaped stigma formed by 2 semi-orbicular lobes horizontally expanding. Distinct features of the new species and its morphologically closest congener, Rhaphiocarpusaxillaris, are compared and discussed. The conservation status of the described species is estimated as Vulnerable (VU D2) according to the IUCN Red List Criteria.
