The taxonomy of Grateloupia sensu lato from South America is still to be fully resolved. Based on the phylogeny of the rbc L and female reproductive structures, we described a new genus, Neorubra, to contain two Peruvian species previously known as Grateloupia denticulata and Prionitis decipiens. Neorubra was characterised by having fivecelled carpogonial branches and four-celled auxiliary-cell branches, fusion of carpogonia and hypogynous cells that formed the basal cell or third cell of the carpogonial branch, a markedly elongated auxiliary-cell fusion cell and pericarps that were well developed on the basal side. Based on the carpogonial and auxiliary-cell ampullae and the formation of secondary connecting filaments, we transferred Grateloupia lancifolia to the genus Phyllymenia.