In revising Myrtaceae Blume correctly concluded in 1849 that Psidium rubrum Lour, from Indo-China could not belong to that neotropical genus. He erected a new genus Macropsidium Bl., to accommodate it, adding at the same time the description of a second new species from the Moluccas. It is desirable to select one of these two syntypes as the lectotype of the genus. I have chosen the one described by Loureiro, which procedure deserves the merit of saving also the generic name Octamyrtus Diels (Bot. Jahrb. 57, 1922, 373) to which I believe Blume’s second species belongs. This leads to the following formal nomenclatural and taxonomic disposition.