A Revision of Brachylophon Oliv. (Malpighiaceae) Based on Morphology, Phylogenetics, and Palynology Reveals a New Species Endemic to Thailand

Abstract

We present a taxonomic revision of Brachylophon (Malpighiaceae) in Thailand, Southeast Asia, based on herbarium collections and a field trip conducted in 2024. Two previously accepted species, B. anatomosans Craib and B. curtisii Oliv., are reported, alongside the new species, B. sirindhorniae Chaisongkram & Ruchis., described and illustrated for the first time. The new species is characterized by having white petals, pedicels 2–5 mm long; filaments 1.5–2.5 mm long; and mericarp 6–7 mm long. A detailed description, illustrations, and a comparison with closely related species are provided to aid in its identification. The discovery of this new species highlights the ongoing need for further exploration and taxonomic study of the genus in Southeast Asia to fully understand its diversity and distribution.