Najas marina

 Subsp intermedia: Sivri superisi; Subsp marina: Dikenli superisi

Dioecious. Plant 10-50 cm ; internodes glabrous to spiny. Leaves 10-25 x 1.5-3.5 mm , spinose-dentate; teeth coarse, 4-10 on each side, occasionally also on abaxial surface of midrib. Sheath to 4 mm, with 0-2 spines on each side; auricles±absent. Flowers solitary; male flowers with spathe, anthers 4-thecous. Fruits 3-5 mm. Fl. 6-7. Lakes, 85-1250 m.

Cosmopolitan except for colder parts of temperate regions.