New record of the seagrass species Halophila major (Zoll.) Miquel in Vietnam: evidence from leaf morphology and ITS analysis

The seagrass (Zoll.) Miquel is reported for the first time from Vietnam. It was found growing with other seagrass species nearshore, 4–6 m deep at Tre Island, Nha Trang Bay. Leaf morphology and phylogenetic analysis based on ribosomal internal transcribed spacer sequences confirmed the identification. There was very little sequence differentiation among samples of collected in Vietnam and other countries in the Western Pacific region. A very low evolutionary divergence among populations was found.