海韭菜（Triglochin maritima}）是水麦冬科植物。

海韭菜的须根肥厚，茎比较短；基生线形的叶子，下部为半圆柱状，基部扩大成鞘，边缘为膜质；顶生总状花序，密布紫绿色小花；卵形果实，具有纵沟，果实成熟后自下而上开裂成6瓣，每瓣内部有一个细长的种子。

Triglochin maritima is a species of flowering plant in the arrowgrass family Juncaginaceae. It is found in brackish marshes, freshwater marshes, wet sandy beaches, fens, damp grassland and bogs. It has a circumboreal distribution, occurring throughout the northern Northern Hemisphere. In the British Isles it is common on the coast, but very rare inland.