A marsh herb. Stems: slender, much branched. Leaves: obtuse to acute, curved inward at the apex, broadly cordate and clasping at the base. Flowers: small, spicate, green or rarely reddish. Fruit: drupelets, obliquely obovoid, obscurely three-carinate on the back, the face curved outwardly towards the top.

This Pondweed, which flourishes in lakes and streams, frequently flowers and fruits under water; its large leaves, heart-shaped at the base, being practically all submerged.

Potamogeton filiformis, or Filiform Pondweed, has numerous very narrow leaves, and flowers which grow in tiny whorls near the top of the slender stems.