Spirodela oligorrhiza (Dotted Duckweed) : MaltaWildPlants.com - the online Flora of the Maltese Islands.
Genus: Spirodela (duck-meal): Go Botany
ファイル:Spirodela polyrhiza sl5.jpg - Wikipedia
Plants | Free Full-Text | Strategies for Intraspecific Genotyping of Duckweed: Comparison of Five Orthogonal Methods Applied to the Giant Duckweed Spirodela polyrhiza