Alisma lanceolatum

Alisma lanceolatum With., Bot. Arr. Brit. Pl. ed. 3 2: 362 1796. (syn: Alisma plantago-aquatica f. aquaticum Gluck; Alisma plantago-aquatica var. lanceolatum (With.) Lej.; Alisma plantago-aquatica f. pumilum Gluck; Alisma plantago-aquatica var. stenophyllum Asch. & Graebn.; Alisma plantago-aquatica f. stenophyllum (Asch. & Graebn.) Buchenau; Alisma plantago-aquatica f. terrestris Gluck; Alisma stenophyllum Sam.; Alisma subcordatum var. stenophyllum (Asch. & Graebn.) Lunell);

lanceleaf water plantain, Narrow leaved water plantain;

Macaronesia, NW. Africa, Europe to China (as per WCSP)

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.^[2] 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.^[3]^[4]^[5]^[6]

It is found in mud and in fresh waters.

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.^[7]

(from Wikipedia on 8.1.16)