Wetland
A bog.
swamp
Fen
Fen. As in Fenway Park being on the road that is the way to the fen.
Swamp?
jamestown
That is a swamp
The Everglades
I am not sure of the answer but it is not a delta since a delta need not be marshy and the question asks about marshy land.
It is an area of marshy wetland formed by the thick growth of a plant (a moss) called "Sphagnum".
Because a cactus can't grow in clayey soil and there is a lot of water in the marshes, the cactus does not need a lot of water
fens