ホテイアオイ
Pleuston are the organisms that live in the thin surface layer existing at the air–water interface of a body of water as their habitat. Examples include some cyanobacteria, some gastropods, the ferns "Azolla" and "Salvinia", and the seed plants "Lemna", "Wolffia", "Pistia", "Eichhornia crassipes" and "Hydrocharis". Some fungi and fungi-like protists may be also found.