[Wikipedia] Origin & Invasiveness: Water pennywort is an aquatic plant, native to the Americas. Due to its popularity as a pond plant, and subsequent escape into rivers, it has established as an invasive alien species in parts of Europe, Australia, Africa and Japan.[1][2][3] It was one of five aquatic plants which were banned from sale in the UK from April 2014, and was the first prohibition of its kind there.[4] On the other hand, it is in decline in parts of its range in the United States.[5] (link added by Mary Ann Machi)
Calflora:
Information on California plants for education, research and conservation,
with data contributed by
public and private institutions and individuals.
[web application]. 2025.The Calflora Database
[a non-profit organization].Available:
https://www.calflora.org/(Accessed: 03/29/2025).
