Abstract
Argostemma iriomotense, previously considered a synonym of A. solaniflorum shortly after its publication, is hereby reinstated based on both morphological and molecular evidence. It can be distinguished morphologically from the latter species by its dwarf plant size, stipules measuring less than 2 mm, leaves which are sparsely strigillose along veins or glabrescent adaxially, and brochidodromous secondary veins that are slightly elevated adaxially and slightly grooved abaxially. Through phylogenetic analysis, samples of A. iriomotense collected from its type locality, together with a newly discovered population in southern Taiwan, form a distinct group separate from A. solaniflorum. These findings support the reinstatement of A. iriomotense from A. solaniflorum. A comprehensive description of its morphology, accompanied by relevant photographs, is provided in this study.