Light micrograph of a North American aquatic plant (Elodea canadensis) leaf cells containing chloroplasts. The tiny green discs within the cells are c

Light micrograph of a North American aquatic plant (Elodea canadensis) leaf cells containing chloroplasts. The tiny green discs within the cells are chloroplasts. Chloroplasts contain the green pigment chlorophyll necessary for photosynthesis. Elodea , often called water weed or pond weed (American water weed), is a fresh water aquatic plant that can be an invasive species (noxious weed). The American water weed lives below the water surface with the exception of small white flowers that bloom at the surface. Elodea is an important part of lake ecosystems. It provides a good habitat for many aquatic invertebrates, young fish and amphibians. Elodea is also used in laboratory experiments and as aquarium vegetation. Magnification: x100 when shortest axis printed at 25 millimetres.