American pondweed (Potamogeton nodosus Poiret) *file325873* Used with permission from UC Berkeley Digital Library Project.
Brazilian elodea (Egeria densa Planchon) *file325874*. Photo credit: David Spencer.
Brazilian elodea (Egeria densa Planchon) *file325875*. Photo credit: David Spencer.
Cattail (Typha latifolia L.) *file325876* Used with permission from UC Berkeley Digital Library Project.
Common waterweed (Elodea canadensis L.) *file325877* Used with permission from UC Berkeley Digital Library Project.
Coontail (Ceratophyllum demersum) *file325878*
Curly leaved pondweed (Potamogeton crispis L.) *file325879* Used with permission from UC Berkeley Digital Library Project.
Duckweed (Lemna spp) *file325880*. Photo taken by David Spencer.
Eurasian watermilfoil (Myriophyllum spicatum L.) *file325881* Used with permission from USDA Aquatic Research Unit.
Eurasian watermilfoil (Myriophyllum spicatum L.) *file325882* Used with permission from USDA Aquatic Research Unit.
Filamentous algae *file325883*
Filamentous algae *file325884*
Micrograph of filamentous algae (Spirogyra spp.) *file325885* Photo credit: Dr. Morgan Vis, Ohio University. Used with permission.
Micrograph of filamentous algae (Oedogonium gracilis) *file325886* Photo credit: Dr. Morgan Vis, Ohio University. Used with permission.
Horned pondweed (Zannichellia palustris L.) *file325887* Photo supplied by U.S. Fish & Wildlife Service.
Hydrilla (Hydrilla verticillata (L.F.) Royle) *file325888*. Photo credit: Dave Spencer
Hydrilla (Hydrilla verticillata (L.F.) Royle) *file325889*. Photo credit: Dave Spencer
Muskgrass (Chara spp.) *file325890*
Naiads (Najas spp.) *file325891* Photo credit: Mike Naylor [(410) 260-8652 or mnaylor@dnr.state.md.us]
Naiads (Najas spp.) *file325892* Photo credit: Mike Naylor [(410) 260-8652 or mnaylor@dnr.state.md.us]
Parrot's Feather (Myriophyllum aquaticum (Vell. Conc.) Verdc.) *file325893* Photo credit: David Spencer.
Planktonic algae *file325894*. Photo credit: Dave Spencer
Sago pondweed (Potamogeton pectinatus L.) *file325895* Photo credit: David Spencer.
Variable leaved pondweed (Potamogeton gramineus) *file325896* Photo credit: David Spencer.
Waterfern (Azolla filiculoides Lam.) *file325897* Used with permission from UC Berkeley Digital Library Project.
Waterfern (Azolla filiculoides Lam.) *file325898* Used with permission from UC Berkeley Digital Library Project.
Waterfern (Azolla filiculoides Lam.) *file325899* Photo credit: David Spencer
Water hyacinth (Eichhornia crassipes (C. Martius) Solms-Laubach) *file325901* Photo credit: David Spencer.
Watermeal (Wolffia spp.) *file325900*
Water hyacinth (Eichhornia crassipes (C. Martius) Solms-Laubach) *file325902* Photo credit: David Spencer.
Water hyacinth (Eichhornia crassipes (C. Martius) Solms-Laubach) *file325903* Photo credit: David Spencer.
Water penny (Hydrocotyl spp.) *file325904*
Water primrose (Ludwigia peploides (Kunth) Raven) *file325905* Used with permission from UC Berkeley Digital Library Project.
Water primrose (Ludwigia peploides (Kunth) Raven) *file325906* Used with permission from UC Berkeley Digital Library Project.
Widgeon grass (Ruppia spp.) *file325908* Photo supplied by U.S. Fish & Wildlife Service.