Myriophyllum (
watermilfoil) is a genus of about 69 species of freshwater aquatic plants, with a cosmopolitan distribution. The center of diversity for
Myriophyllum is Australia with 43 recognized species (37 endemic). Its name comes from Latinized Greek, "myrio" meaning "ten thousand", or figuratively "too many to count", and "phyllum" meaning "leaf".
(Wikipedia)