Assertion: european water chestnut | /r/AtLocation | the u.s.
Facets:
value: from eastern europe
type: LOCATION
value: in the 1920s
type: TEMPORAL
Source sentences:
text: The European water chestnut (Trapa natans) is an invasive, partially submerged aquatic plant that was introduced to the U.S. in the 1920s from Eastern Europe.