Elodea canadensis Canadian Waterweed

A submerged, aquatic perennial with tongue-shaped leaves arranged in whorls of 3. It is a native of North America which was introduced as an aquarium escape and first recorded wild in Britain in 1842. Since then it has undergone a rapid spread in slow-moving, mesotrophic or eutrophic waters such as canals. It is dioecious but all plants in Britain are females and it has spread purely by vegetative means. In recent decades it has undergone a general decline in Britain which has been concommitant with the range expansion of other aquatic neophytes, particularly Nuttall's Waterweed (Elodea nuttallii) which has replaced it in many areas. It has a scattered distribution in West Glamorgan, mostly occurring in canals, but it has become less common in the last 50 years.

Neophyte