Abstract:A new species of Gracilariopsis, Gp. nhatrangensis sp. nov. Le et Lin, is described from Vietnam. Gracilariopsis nhatrangensis is unique in consisting of 1-15 main axes arising from a discoid holdfast and the main axes bearing numerous, racemose branchlets. The molecular analysis based on the rbcL gene of the species of Gracilariopsis sourced worldwide with the chorda-type spermatangial conceptacles supports the
proposal of this new species.