Rhizomatous. Stems usually much less than 1 m. Leaves either all submerged or submerged and floating. Floating leaves without a joint at point of attachment of petiole and lamina; petiole 3-6 cm; lamina 3-6 cm, narrowly elliptic to ovate-elliptic or ovate, obtuse at apex and base, green, opaque, ± dull. Submerged leaves translucent, ± sessile, lanceolate or lanceolate-oblong, to 70 x 3-10 mm, acute to acuminate, margin ±minutely denticulate. Stipules to 4 cm, herbaceous. Peduncles 4-6 cm, thickened upwards. Spikes c. 3 cm. Fruitlets 2-3 mm, roundish. Fl. 5-7. Lakes, rivers, c. l00-1970 m.
Much of Europe , Caucasia, N.W. Iran, W. Pakistan, Siberia, N. America.