Abstract
Argostemma sawmlianae (Rubiaceae), a new species from Mizoram, Northeast India, within the Indo-Burma hotspot, is described and illustrated. The species is compared with its allied species A. courtallense and A. sarmentosum, from which it differs by a set of distinctive morphological characters that include a pair of larger sessile leaves (11.5-18.5 cm long), longer peduncle (4-6.5 cm long), more flowers per cyme (8-33) and campanulate corolla with falcate lobes, reflexed and prominently rolled backward. The molecular analyses based on matK (cpDNA) and ITS2 (nrDNA) sequences support the morphological evidences confirming A. sawmlianae as a distinct new species. The newly discovered species is provisionally categorized as Critically Endangered (CR) in accordance with the IUCN Red List Categories and Criteria (IUCN 2024) based on available data.