wild rice

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of several aquatic grasses of the genus Zizania of North America and Asia, especially Z. palustris of north-central North America, which is harvested for its edible grain.
• noun The grain of any of these plants,

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Any one of the four species of grasses which form the genus Zizania, which have edible grains and edible stems.
• noun The edible grain (the edible rice) which is harvested from these grasses.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun perennial aquatic grass of North America bearing grain used for food
• noun grains of aquatic grass of North America