The floating or emergent leaves have blades up to 10 centimeters long by 4 wide and lance-shaped to heart-shaped.

Each flower has tiny green sepals and white or pink petals a few millimeters long.

[5] A pathogenic fungus, Rhynchosporium alismatis, was discovered on the plant, and it has become an option for biological control as a mycoherbicide.

The fungus causes chlorosis and necrosis of the leaves on the mature plant and stunting of immature individuals.

[4] The fungus can kill seedlings, and if it infects the inflorescence of the weed it can reduce seed weight and viability.