Freshwater ecosystems include lakes, rivers, ponds, and streams; they all have low salt concentration. Ponds and lakes can vary in size and have limited plant and animal species. Rivers and streams originate in headwaters; you can see different specie as you move from the headwaters to the mouth of the river; light and oxygen are the determining factors. Wetlands are standing water like marshes and swamps; they have a large variety of plant and specie, including reptiles, amphibians, and birds.

American lotus
American lotus, Center for Aquatic and Invasive Plants, University of Florida, Photos and a 2-3 minute video.
http://plants.ifas.ufl.edu/node/10
Blue-green Algae
Blue-green Algae, Florida Department of Environmental Protection, A photo and description.
http://www.dep.state.fl.us/water/bgalgae/
Buttonbush
Buttonbush, Aquaplant @ Texas A&M University, Photo and description.
http://aquaplant.tamu.edu/plant-identification/alp...
Carnivorous Plants / Insectivorous Plants
Carnivorous Plants / Insectivorous Plants, Botanical Society of America, A gallery of photos; click on a photo for more photos and information
http://www.botany.org/Carnivorous_Plants/
Carnivorous Plants vs Herbivorous Insects
Carnivorous Plants vs Herbivorous Insects, YouTube.com, Video length: 01:54.
http://www.youtube.com/watch...
Common Duckweed
Common Duckweed, AcquaPlant, Texas AgriLife Extension Service, Photo and description.
http://aquaplant.tamu.edu/plant-identification/alp...
Coontail
Coontail, Center for Aquatic and Invasive Plants, University of Florida, Text, photos, and a 2-3 minute video.
https://plants.ifas.ufl.edu/plant-directory/cerato...
Cypress Trees
Cypress Trees, University of Southern Indiana, Photos and description; check out those "knees".
http://www.usi.edu/science/biology/twinswamps/cypr...
Diatoms
Diatoms, Kids.Net.Au, Encyclopedic article for younger students.
http://encyclopedia.kids.net.au/page/di/Diatoms
Diatoms: Life History and Ecology
Diatoms: Life History and Ecology, University of California Museum of Paleontology, Text and two images; click to enlarge.
http://www.ucmp.berkeley.edu/chromista/diatoms/dia...
EEK! Eurasian Water-milfoil
Eurasian Water-milfoil, EEK!m Wisconsin Department of Natural Resources, Information for younger students.
http://dnr.wi.gov/org/caer/ce/eek/veg/plants/euras...
Everglades Habitat Images
Everglades Habitat Images, National Park Service, Visit the web site for the photos.
http://www.nps.gov/ever/parknews/evergladeshabitat...
Flowering Plants that Grow on Bogs and Fens
Flowering Plants that Grow on Bogs and Fens, By Andy Fyon, Ontario Wild Flower, Close-up photos with descriptions.
http://www.ontariowildflower.com/bogfen.htm
Macrophytes
Macrophytes, Biology-Online.org, Mostly text with an illustration showing examples of macrophytes.
http://www.biology-online.org/articles/macrophytes...
Nelumbo lutea, the American Lotus
Nelumbo lutea, the American Lotus, Wikipedia.com, Article with photos; click to enlarge.
http://en.wikipedia.org/wiki/Yellow_lotus
Plant Identification
Plant Identification, Aquaplant, Texas AgriLife Extension Service, Department of Wildlife & Fisheries Sciences, Texas A&M University, Here you can identify aquatic plants using alphabetical or
http://aquaplant.tamu.edu/plant-identification/
Sherpa Guides: The Okefenokee Swamp Flora and Fauna
Sherpa Guides: The Okefenokee Swamp Flora and Fauna, By Richard J. Lenz, Photos with descriptions.
http://www.sherpaguides.com/georgia/okefenokee_swa...
The Charms of Duckweed
The Charms of Duckweed, by John W. Cross, Missouri Botanical Garden, A combination of text, illustration, and photos.
http://www.mobot.org/jwcross/duckweed/duckweed.htm
The Value of Riparian Vegetation
The Value of Riparian Vegetation, King County, State of Washington, Text and one photo.
http://www.kingcounty.gov/environment/animalsAndPl...
Water Lily Pictures and Lily Pad Pictures
Water Lily Pictures and Lily Pad Pictures BetterPhoto.com Visit the site for photos.
http://www.betterphoto.com/gallery/dynoGall2.asp.....
What Are The Common Plants, Animals, And Insects In A Swamp?
What Are The Common Plants, Animals, And Insects In A Swamp?, Michigan Environmental Education Curriculum, Wetland Ecosystems, Visit the web site to view the photos.
http://techalive.mtu.edu/meec/module12/Creaturesof...
Willow
Willow, Aquaplant @ Texas A&M University, Photo and description.
http://aquaplant.tamu.edu/plant-identification/alp...