Duckweed, Lemna minor is a tiny pond plant that is fast growing especially when nutrient levels are high. The worlds smallest known flowering plant though its not very visible to the naked eye. Excellent nutrition for koi and turtles. Carried often from one body of water to another on backs and feet of ducks; hence the name Duckweed. Sold in large half pound portions. Note, other companies only offer cup sized portions. Native and present in most of the United States. Zone 4.