What is "stratiotes aloides"

Water soldier \Wa"ter sol`dier\ (Bot.) An aquatic European plant ( Stratiotes aloides) with bayonet-shaped leaves.

Statiotes aloides, commonly known as the water soldiers or water pineapple, is a submerged aquatic plant native to Europe and northwestern Asia. In Britain it was once common in East Anglia and still is in many places, particularly wet ditches and healthy ponds.It is the only species in the genus Stratiotes.