Lemna
Lemna gibba
Lemna gibba L.
Engl.: fat duckweed.
Lemna minor
Lemna minor L.
Engl.: common duckweed, duckweed.
Bot. syn.: Lenticula minor (L.) Scop.
Lemna trisulca
Lemna trisulca L.
Engl.: star duckweed.
A herbal distance course
Henriette's herbal is one of the oldest and largest herbal medicine sites on the net. It's been online since 1995, and is run by Henriette Kress, a herbalist in Helsinki, Finland.