A wetland tyro may find himself wondering whether he is standing in a marsh or a swamp. Looking down will not solve the problem—his feet will be wet in either case. But if he surveys the area and finds it composed primarily of grasses, rushes, reeds, and cattails, he can be confident it is a marsh he inhabits—swamps are dominated by trees. If he dips a finger in the water and raises it to his lips, he will know if he is in a coastal salt marsh, whose hay is much prized by gardeners for mulch. In general terms, marshes are likely to be found in the North and called swamps in the South, with ciénega the preferred term for marsh throughout parts of the West. Fresh or saline, tropical or temperate, marshes are crucial and fecund habitat, having lent their name to species as diverse as the marsh hawk and marsh marigold. As the author Bern Keating writes, “Poets who know no better rhapsodize about the peace of nature, but a well-populated marsh is a cacophony.”

Bill McKibben