microscopic algae star duckweed or lemna trisulca or schur or ivy-leaved duckweed

algae aquatic araceae biology blade bluish botanical botany budding cover develop dirt duckweed ecology flora flower freshwater garden green illustration isolated lake leaf lemna monocot nature ovary plant pond reddish reservoir river root shur small species stalk star summer sunlight surface swamp thallus trisulca underwater vegetative vein water weed yellowish