Some bogs are totally overgrown and some consist of open water surrounded by floating vegetation. Acid-tolerant plants found in and around bogs include woody plants such as labrador tea, poison sumac, tamarack, and black spruce. Many species of orchids prefer bog habitats, as do insect-eating sundews and pitcher plants. Bogs are usually only found in the northern part of Michigan. Fens are similar to bogs except that the soils are more alkaline because they result from water passing through calcareous deposits.
Fens have a higher plant diversity than bogs due to higher nutrient levels.
Fens can be found in the southern part of Michigan. The amount of water can fluctuate seasonally or from year to year. They are dominated by soft-stemmed emergent plants such as cattails and rushes. In Michigan, marshes can be found at the edge of some rivers and lakes, in lowlands and depressions, and in swales between sand dunes. The soil is saturated throughout the growing season.