Resurrection of Drypetesnienkui (Putranjivaceae), endemic to Hainan, China

Drypetesnienkui (Putranjivaceae), described from Hainan, China, has long been treated as a synonym of D.indica. Both species belong to a distinctive group of Asian species characterized by perulate buds that give rise to shoots bearing flowers or inflorescences proximally and leaves distally, 2–3-carpellate ovaries, and elongate styles. However, D.nienkui fundamentally differs from D.indica in inflorescence architecture and fruiting pedicel length; these or other characters also distinguish D.nienkui from the remaining species in this group. Drypetesnienkui therefore deserves recognition as a distinct species endemic to Hainan. An expanded description of the species is provided along with a key to the related species.