pondweed

noun7

1. •
   Any of several plants that grow in ponds or similar aquatic conditions.
2. •
   Potamogeton, a diverse and worldwide genus
3. •
   Elodea, found in North America
4. •
   Azolla, of cosmopolitan distribution

   • If you have ever had a pond you will know Azolla, a.k.a. pondweed, duckweed fern or fairy moss. — 2018
5. •
   Aponogeton, in Africa, Asia and Australasia
6. •
   opposite-leaved pondweed, Groenlandia densa, only plant of its genus, found chiefly in the Mediterranean region.
7. •
   Charales, an order of green algae