What is "echinodorus"

Echinodorus (burhead or Amazon sword plant) is a genus of plants in the family Alismataceae and distributed in the Western Hemisphere from the central United States to Argentina. Its scientific name is derived from Ancient Greek echius – rough husk, and doros – leathern bottle, alluding to ovaries, which in some species are armed with persistent styles, forming prickly head of fruit. Some of the species are commonly cultivated in artificial aquatic habitats.