Wetlands occur throughout the world and support a wide variety of plants and animals. The major types of wetlands include bogs, fens, marshes, and swamps. Bogs and fens are most common in cold climates and are characterized by extensive deposits of partially decayed plant material called peat. Bogs have highly acidic soils. The soils of fens are not highly acidic.
Mosses are abundant in both bogs and fens.
Marshes and swamps usually lack peat deposits and occur in both warm and cold climates. Marshes are found in the shallow waters of lakes and streams. Cattails, horsetails, bulrushes, and other nonwoody plants are common in marshes. Swamps tend to develop in areas that are not permanently flooded. Trees and shrubs are the most prominent plants in swamps.