- Name also: Seaside Arrowgrass, Shore Arrowgrass, Common Arrowgrass
- Family: Arrowgrass Family – Juncaginaceae
- Growing form: Perennial, often tufted herb. Rootstock short, stout, erect–ascending. With short runners.
- Height: 30–70 cm (12–28 in.). Stem unbranched, approx. 2 mm (0.08 in.) thick, base thickened, surrounded by leaf remains.
- Flower: Regular (actinomorphic), 3–4 mm (0.12–0.16 in.) wide. Tepals 6, like sepals, dark. Stamens 6. Pistils 6. Inflorescence a long, dense raceme, flower-stalks short, ascending oblique.
- Leaves: With basal rosette, stalkless, erect. Blade linear, semi-cylindrical, 1–3 mm (0.04–0.12 in.) wide, fleshy.
- Fruit: Widely egg-shaped, 2.5–6 mm (0.1–0.24 in.) long, 6-sectioned schizocarp.
- Habitat: Seashore meadows, stony places, often by the waterline, also on fens.
- Flowering time: June–July.
While the docks (Rumex spp.) have a bitterly refreshing taste of oxalic acid, arrowgrasses are clearly salty. Sea Arrow-grass is also evidently pleasing to cattle because it is always eaten first on seaside meadows. On the shores of the North Sea people have used sea arrow-grass as a nutritional food in the same way as spinach, and the slightly odd whiff of chlorine that it gives off disappears when it is boiled. It is easy to get a taste of sea arrow-grass on the shores of the Baltic because it is one of Finland’s most common seashore plants on both sides of the tide line. Its typical habitats are usually affected by the movements of the ice as the remains of shoots are cut by the ice during the winter. New shoots are produced by the plant the following summer. Sea arrow-grass doesn’t grow in all the shore areas however and the species is becoming rarer as the salt-content in the sea decreases. The soil must usually have a few milligrams of salt for the plant to be able to sprout and grow. On the other hand, sea arrow-grass can also be found inland – in the rich eutrophic fens of Kuusamo.