Triglochin maritima is a species of flowering plant in the arrowgrass family Juncaginaceae.

It is similar to marsh arrowgrass (Triglochin palustris) but has the following differences: it has stolons, is stouter.

However, this is usually when the plant is distressed in drought conditions or due to over harvesting, usually by grazing animals.

There is a common belief that this species has been known to cause losses in cattle, with green leaves being more toxic than dried material, yet sheep and deer graze on the plant, especially in rural seaside areas.

It could be that belief in the plants' toxicity is apocryphal and based on anecdotal evidence.