Aquatic plants are really interesting, and vintage story lacks them which is sad to me. Some could be used as food other as pure ornamental plants or even fibers so lets begin:
Lotus- This one is my favourite that will be on this list. Sacred lotus would be found in subtropical or tropical biomes while american lotus would be found in temperate biomes and subtropical biomes both would grow in ponds and lakes in their biomes. This plant could be used as food because of tubers (which would function same as reed tubers) and seeds. Lotus would grow faster in warmer shallow water but would have more chances to survive winter in deeper water which wouldnt freeze (American lotus would be more hardy). Thats it for this plant
Water lilies- They would be found in lakes and ponds. European water lily would be found in temperate biomes while blue lotus (not true lotus) would be found in tropical biomes. Raw water lily bulbs would be toxic, after roasting they would turn edible (water lily tuber would function same as reed tuber though these belonging to blue lotus would die in winter while these belonging to european water lily would survive).
Flowering rush- Last one for today. This plant would be found in temperate biomes in shallow water close or on shore. Flowering rush has rhizomes that can be used to plant to it in shallow water and are edible even raw. It can survive winter in shallow water on its own. Bees also love it. Thats all
I hope you like my idea though it is probaly bad
