Definition that contains pond scum
- order zygnemales pond scums; desmids
- order zygnematales pond scums; desmids
- family zygnemataceae pond scums: common freshwater algae forming green slimy masses
- zygnemales pond scums; desmids
- zygnemataceae pond scums: common freshwater algae forming green slimy masses
- zygnematales pond scums; desmids