Taxonomic clarifications of Homalomena hainanensis and Schismatoglottis hainanensis, with floristic notes on the Araceae family in Hainan Island

Summary Homalomena hainanensis H.Li and Schismatoglottis hainanensis H.Li, two historically enigmatic aroid names published from Hainan Island, have long presented taxonomic ambiguity due to unclear protologues and poorly preserved type materials. Through careful examinations of the types and new materials from recent fieldwork, the identities of both names are clarified with new interpretations. Homalomena hainanensis is epitypified here, with the recently published H. perplexa K.Z.Hein, Vuang, Bao & V.S.Dang placed in synonymy, and Schismatoglottis hainanensis is shown to be conspecific with the Central Vietnamese S. cadierei Buchet & Gagnep. ex S.Y.Wong & P.C.Boyce. We also confirm the occurrence of Anadendrum chlorospathum V.D.Nguyen, Đinh & P.C.Boyce in Hainan for the first time, resolving a long history of misidentification. These taxonomic clarifications, together with literature and herbarium records, reveal an Indochina–Hainan disjunct distribution for these three species and highlight the tropical, low-endemism aroid flora of Hainan, whose close affinity with that of Vietnam supports a continental origin and suggests geologically recent eustatic floristic exchanges.