Ludwigia longifolia (Onagraceae), an alien herb newly invaded to Japan.
Ludwigia longifolia (DC.) H. Hara, an annual or perennial onagraceous herb native to Brazil and northern Argentina is reported first as naturalized in Tateyama, Chiba Pref., Japan. The plant is established in the habitat since 2013, and may naturalize widely in wet habitats of Japan in future. It has already naturalized widely in the East Coast of Australia from the 1990's.