It is found in mud and in fresh waters.In England and Wales it is occasionally locally found, in Ireland it is rare, and Scotland it is very rare.This species is a weed of rice fields in many areas, including New South Wales and California.Alisma lanceolatum is a species of aquatic plant in the water plantain family known by the common names lanceleaf water plantain and narrow-leaved water plantain. It is widespread across Europe, North Africa and temperate Asia. It is naturalized in Australia, New Zealand, Oregon, California and British Columbia. It is considered a noxious weed in some places.
This is a perennial herb growing from a caudex in the water or mud. It produces lance-shaped leaves 12 to 20 centimeters long and 4 wide on long petioles; leaves which remain submerged in water are smaller and less prominently veined. The inflorescence is mostly erect and up to half a meter tall.
It is a wide array of small pink-petalled flowers, which open in the morning, from June until August. The fruit is a tiny achene up to 2 or 3 millimeters long clustered into an aggregate fruit of about 20 units.
The water plantain Alisma plantago-aquatica has acute leaf tips not tapering to a stalk.