Used in: Environments (2nd edition, FOSS CA), Populations and Ecosystems
Duckweed – Lemna minor
Background. Lemna, also known as duckweed, is a tiny floating green plant that looks superficially like a bunch of diminutive lily pads. An individual plant never gets any larger than a few millimeters, but they can proliferate to cover huge areas of water completely. Ducks are fond of it and do their part to keep waterways open, along with many other animals that find it a good food source. Lemna is a good plant for population studies because of the rate at which it multiplies by division of the fleshy leaves. Lemna is the smallest of the flowering plants, but it rarely blooms. Care of aquatic plants is easy. Keep plenty of water in their container.
What to do when the duckweed arrives. Transfer contents of shipping container to small sieve or dip net. Rinse in dechlorinated or spring water. Introduce duckweed to aquarium where it will float and provide food for other organisms.
What to do with them when the investigations are completed. Maintain the duckweed in an aquarium or share it with another classroom that will conduct the module next. Fish, such as goldfish, will nibble on the duckweed for food. Duckweed should never be released into local ponds unless it was collected there.