N. Vietnam, Prov. Quang Binh, about 60 km to NW from Dong Hoi city. In shallow slightly salted water of Gianh river near ocean coast. Sea grass with leaves up to 20 cm lg. Abundant at 0.1-1 m depths. VH 4570 14.05.1997 International Botanical Expedition of the U.S.A. National Geographic Society (grant No 5803-96)