Cypress trees have "knees" that extend from the root system to above the average water level. The functions of these knees are believed to anchor the tree and are possibly a means of respiration when roots are flooded.
Cypress Knees in Swamp
From Steve Nix, About.com
The primary wildlife inhabitants of swamp forests are reptiles, amphibians, fish, birds, raccoons, opposums, wild pigs and invertebrates.
Cypress in swamp near Pearl River Mississippi
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