FlickrLickr
Monochoria
Monochoria vaginalis

Monochoria (Monochoria vaginalis) is an invasive plant. It is a native of Tropical Asia.

Monochoria vaginalis is an attached aquatic annual or perennial herb with emersed leaves, to 50 cm tall. It is a serious weed of rice fields in much of eastern and southeastern Asia. Dense colonies in shallow water may considerably reduce yields.
Summaries of State Plant Protection Laws and Regulations
Florida   Illinois   Indiana