Peat swamp forests are swamp forests where waterlogged soils prevent woody debris from fully decomposing, which over time creates a thick layer of acidic peat.

Coniferous swamps are forested wetlands in which the dominant trees are lowland conifers such as northern white cedar. The soil in these swamp areas is typically saturated for most of the growing season and is occasionally inundated by seasonal storms or by winter snow melt. The substrate is usually organic in nature and may contain peat in varying amounts or be composed entirely of muck. The swamp substrate is typically nutrient-rich and neutral to alkaline but can be acidic and nutrient-poor. Coniferous swamps vary in composition, with different species of conifer dominating, and varying amounts of deciduous hardwoods growing within the swamp. A wide diversity of plants is represented within the swamps, with certain species dominating in a variety of microhabitats dependent on factors such as available sunlight (as in cases of trees downed by wind or disease), soil Ph, standing groundwater, and differences of elevation within the swamp such as tussocks and nurse logs.

Peat swamp forests are tropical moist forests where waterlogged soil prevents dead leaves and wood from fully decomposing. Over time, this creates a thick layer of acidic peat. Large areas of these forests are being logged at high rates. Peat swamp forests are typically surrounded by lowland rain forests on better-drained soils, and by brackish or salt-water mangrove forests near the coast. Tropical peatlands, which coexist with swamp forests within the tropical and subtropical moist broadleaf forests biome, store and accumulate vast amounts of carbon as soil organic matter - much more than natural forests contain. Their stability has important implications for climate change; they are among the largest near-surface reserves of terrestrial organic carbon. Tropical peat swamp forests are home to thousands of animals and plants, including many rare and critically endangered species such as the orang-utan and Sumatran tiger, whose habitats are threatened by peatland deforestation.

In usage in the United States, a bayou is a body of water typically found in a flat, low-lying area, and can be either an extremely slow-moving stream or river (often with a poorly defined shoreline), or a marshy lake or wetland. The name "bayou" can also refer to a creek whose current reverses daily due to tides and which contains brackish water highly conducive to fish life and plankton. Bayous are commonly found in the Gulf Coast region of the southern United States, notably the Mississippi River Delta, with the states of Louisiana and Texas being famous for them. A bayou is frequently an anabranch or minor braid of a braided channel that is moving much more slowly than the mainstem, often becoming boggy and stagnant. Though fauna varies by region, many bayous are home to crawfish, certain species of shrimp, other shellfish, catfish, frogs, toads, American alligators, American crocodiles, herons, turtles, spoonbills, snakes, leeches, and many other species.

A bog is a wetland that accumulates peat, a deposit of dead plant material—often mosses, and in a majority of cases, sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, quagmire, and muskeg; alkaline mires are called fens. They are frequently covered in ericaceous shrubs rooted in the sphagnum moss and peat. The gradual accumulation of decayed plant material in a bog functions as a carbon sink. Bogs occur where the water at the ground surface is acidic and low in nutrients. In some cases, the water is derived entirely from precipitation, in which case they are termed ombrotrophic (rain-fed). Water flowing out of bogs has a characteristic brown colour, which comes from dissolved peat tannins. In general, the low fertility and cool climate results in relatively slow plant growth, but decay is even slower owing to the saturated soil. Hence peat accumulates. Large areas of landscape can be covered many metres deep in peat. Bogs have distinctive assemblages of animal, fungal and plant species, and are of high importance for biodiversity, particularly in landscapes that are otherwise settled and farmed.

A marsh is a wetland that is dominated by herbaceous rather than woody plant species. Marshes can often be found at the edges of lakes and streams, where they form a transition between the aquatic and terrestrial ecosystems. They are often dominated by grasses, rushes or reeds. If woody plants are present they tend to be low-growing shrubs. This form of vegetation is what differentiates marshes from other types of wetland such as swamps, which are dominated by trees, and mires, which are wetlands that have accumulated deposits of acidic peat. Marshes provide a habitat for many species of plants, animals, and insects that have adapted to living in flooded conditions. The plants must be able to survive in wet mud with low oxygen levels. Many of these plants therefore have aerenchyma, channels within the stem that allow air to move from the leaves into the rooting zone. Marsh plants also tend to have rhizomes for underground storage and reproduction. Familiar examples include cattails, sedges, papyrus and sawgrass. Aquatic animals, from fish to salamanders, are generally able to live with a low amount of oxygen in the water. Some can obtain oxygen from the air instead, while others can live indefinitely in conditions of low oxygen. Marshes provide habitats for many kinds of invertebrates, fish, amphibians, waterfowl and aquatic mammals. Marshes have extremely high levels of biological production, some of the highest in the world, and therefore are important in supporting fisheries. Marshes also improve water quality by acting as a sink to filter pollutants and sediment from the water that flows through them. Marshes (and other wetlands) are able to absorb water during periods of heavy rainfall and slowly release it into waterways and therefore reduce the magnitude of flooding. The pH in marshes tends to be neutral to alkaline, as opposed to bogs, where peat accumulates under more acid conditions. Saltwater marshes are found around the world in mid to high latitudes, wherever there are sections of protected coastline. They are located close enough to the shoreline that the motion of the tides affects them, and, sporadically, they are covered with water. They flourish where the rate of sediment build-up is greater than the rate at which the land level is sinking. Salt marshes are dominated by specially adapted rooted vegetation, primarily salt-tolerant grasses. Salt marshes are most commonly found in lagoons, estuaries, and on the sheltered side of shingle or sandspit. The currents there carry the fine particles around to the quiet side of the spit and sediment begins to build up. These locations allow the marshes to absorb the excess nutrients from the water running through them before they reach the oceans and estuaries.
Ranging greatly in both size and geographic location, freshwater marshes make up the most common form of wetland in North America.

Wet meadows occur in areas such as shallow lake basins, low-lying depressions, and the land between shallow marshes and upland areas. They also occur on the edges of large lakes and rivers. Wet meadows often have very high plant diversity and high densities of buried seeds. They are regularly flooded but are often dry in the summer.
Vernal pools are a type of marsh found only seasonally in shallow depressions in the land. They can be covered in shallow water, but in the summer and fall, they can be completely dry. In western North America, vernal pools tend to form in open grasslands, whereas in the east they often occur in forested landscapes. Further south, vernal pools form in pine savannas and flatwoods. Many amphibian species depend upon vernal pools for spring breeding; these ponds provide habitat free from fish which eat the eggs and young of amphibians. An example is the endangered gopher frog (Rana sevosa). Similar temporary ponds occur in other world ecosystems, where they may have local names. However, the term vernal pool can be applied to all such temporary pool ecosystems.
Playa lakes are a form of shallow freshwater marsh that occurs in the southern high plains of the United States. Like vernal pools, they are only present at certain times of the year and generally have a circular shape. As the playa dries during the summer, conspicuous plant zonation develops along the shoreline.
Prairie potholes are found in the northern parts of North America as the Prairie Pothole Region. These landscapes were once covered by glaciers, and as a result shallow depressions were formed in great numbers. These depressions fill with water in the spring. They provide important breeding habitats for many species of waterfowl. Some pools only occur seasonally while others retain enough water to be present all year.
Many kinds of marsh occur along the fringes of large rivers. The different types are produced by factors such as water level, nutrients, ice scour, and waves.

A mire or quagmire, sometimes called a peatland, is a wetland terrain without forest cover, dominated by living, peat-forming plants. For botanists and ecologists, the term peatland is a more general term for any terrain dominated by peat to a depth of at least 30 cm (12 in), even if it has been completely drained (i.e., a peatland can be dry, but a mire by definition must be wet). There are two types of mire: bogs and fens. A bog is a landform that due to its location relative to the surrounding landscape obtains most of its water from rainfall (i.e., is ombrotrophic), while a fen is located on a slope, flat, or depression and gets its water from both rainfall and surface water. Also, while a bog is always acidic and nutrient-poor, a fen may be slightly acidic, neutral, or alkaline, and either nutrient-poor or nutrient-rich. A mire is distinguished from a swamp by its lack of a forest canopy; although some bogs may support limited tree or bush growth, mires are dominated by grass and mosses. A mire is distinguished from a marsh by its water nutrients and distribution: marshes are characterized by nutrient-rich stagnant or slow-moving waters while mire waters are located mostly below the soil surface level. A mire is also distinguished from a marsh by its plant life: marsh plants are generally submerged or floating-leaved while those in a mire are not. Relying on rainwater for nutrient input, mires are usually deficient in both nitrogen and phosphorus and may vary widely with regard to nitrogen. The term quagmire is a variant term for mire, the prefix quag- having variously been written as qua-, quab-, quad-, quake-, qual-, quave-, and quaw- in the 16th and 17th centuries, and afterwards the prefixes bob-, gog-, and wag- having also been used in the same way. The relationship among these terms and prefixes is not linguistically clear, though they may all have been an attempt to express the same general idea of shaky, wet, unsteady ground that cannot support the weight of a man or large animal and is therefore dangerous to enter and difficult to leave.

A blackwater river is a type of river with a deep, slow-moving channel flowing through forested swamps or wetlands. As vegetation decays, tannins leach into the water, making a transparent, acidic water that is darkly stained, resembling tea or black coffee. Most major blackwater rivers are in the Amazon Basin and the Southern United States. Some rivers in temperate regions, which drain or flow through areas of dark black loam, are simply black due to the colour of the soil; these rivers are black mud rivers. There are also black mud estuaries. Blackwater rivers are lower in nutrients than whitewater rivers and have ionic concentrations higher than rainwater. The unique conditions lead to flora and fauna that differ both from whitewater and clearwater rivers. Black and white waters differ significantly in their ionic composition. Black waters are more acidic, resulting in an aluminium concentration greater than that of the more neutral white waters. The major difference is the concentrations of sodium, magnesium, calcium and potassium; these are very low in black waters. This has ecological implications. Some animals need more calcium than is available in blackwaters, so for example, snails, which need much calcium to build shells, are not abundant in blackwaters. The lack of dissolved ions in black waters results in a low conductivity, similar to that of rainwater. Black and white waters differ in their planktonic fauna and flora. The black water holds greater numbers of rotifers but fewer crustaceans and mites. These crustaceans are important foods for larval fish. The zones where the two waters mix are attractive to ostracods and young fish. These mixing zones tend to have many animals. Blackwater rivers resemble clearwater rivers in having a low conductivity and relatively low levels of dissolved solids, but clearwater rivers have water that at most only is somewhat acidic (typical pH ~6.5) and very clear with a greenish colour.

Patches of quicksand present a deceptively solid appearance (appearing as undergrowth or open land) that may trap careless characters. A character approaching a patch of quicksand at a normal pace is entitled to a perception check to spot the danger before stepping in, but charging or running characters don’t have a chance to detect a hidden bog before blundering in. A typical patch of quicksand is 20 feet in diameter; the momentum of a charging or running character carries him or her D4 ×2 feet into the quicksand. Characters in quicksand must make a Swim check every round to simply tread water in place, or to move 5 feet in whatever direction is desired. If a trapped character fails this check by 5 or more, he sinks below the surface and begins to drown whenever he can no longer hold his breath.
Characters below the surface of a bog may swim back to the surface with a successful Swim check. Pulling out a character trapped in quicksand can be difficult. A rescuer needs a branch, spear haft, rope, or similar tool that enables him to reach the victim with one end of it. Then he must make a Strength check to successfully pull the victim, and the victim must make a Strength check to hold onto the branch, pole, or rope. If the victim fails to hold on, he must make a Swim check immediately to stay above the surface. If both checks succeed, the victim is pulled 5 feet closer to safety.

Common in moors, hedgerows are tangles of stones, soil, and thorny bushes. Narrow hedgerows function as low walls, and it takes 15 feet of movement to cross them. Wide hedgerows are more than 5 feet tall and take up entire squares. They provide total cover, just as a wall does. It takes 4 squares of movement to move through a square with a wide hedgerow; creatures that succeed on a Climb check need only 2 squares of movement to move through the square.

Some marshes, particularly swamps, have trees just as forests do, usually clustered in small stands. Paths lead across many marshes, winding to avoid bog areas. As in forests, paths allow normal movement and don’t provide the concealment that undergrowth does.

Alligator: Alligators are smaller and less aggressive than crocodiles, and have a broad, round snout. Unlike a crocodile, you can’t see an alligator’s teeth when its mouth is closed. Alligators generally hunt prey at night, occasionally forming loose social groups for this purpose. They are cold-blooded and bask in the sunlight to regulate their internal temperatures.

Bird: a distant ancestral relative of the reptile family. By comparison, a bird is typified by a covering of feathers (that
evolved from scales), a four-chambered heart served by an aortic arch, fully separate systemic and pulmonary circulations, a warm-blooded metabolism, large eggs with hard calcareous shells, forelimbs modified into wings, jaws without teeth, and a breastbone enlarged by a ventral keel for the attachment of the pectoral muscles that control the action of the wings. Common birds that live in or migrate through swamps include the common loon, white pelican, brown pelican, anhinga, great blue heron, great egret, cattle egret, marsh bittern, green heron, snowy egret, little blue heron, tricoloured heron, night heron, white ibis, glossy ibis, wood stork, snow goose, whistling swan, wood duck, mallard duck, mottled duck, turkey vulture, osprey, swallow-tailed kite, bald eagle, harrier, red-shouldered hawk, merlin, peregrine falcon, clamper rail, rail, sora, purple gallinule, moorhen, coot, plover, oystercatcher, stilt, avocet, spotted sandpiper, whimbrel, common snipe, woodcock, laughing gull, tern, mourning dove, black skimmer,
screech owl, barred owl, belted kingfisher, ruby-throated hummingbird, redheaded woodpecker, yellow-bellied sapsucker, flycatcher, blue jay, crow, purple martin, tree swallow, marsh wren, mockingbird, warbler, water thrush, swamp sparrow, and red-winged blackbird.

Fish: A fish is typified by an elongated, somewhat spindle-shaped body terminating in a broad caudal fin and limbs in the form of fins (when present at all). Fish have two-chambered hearts by which blood is sent through the thoracic gills to be oxygenated before passing to the organs and tissues of the body and returning in venous condition to the heart. Fish are usually oviparous, often producing great numbers of eggs which are fertilized in the water after they are laid. Common freshwater fish that live in swamps include the longnose gar, bowfin, common carp, golden shiner, fathead minnow, brown bullhead catfish, channel catfish, grass pickerel, chain pickerel, warmouth, bluegill, largemouth bass, black crappie, and yellow perch.

Frog: a smooth-skinned, web-footed, tailless, agile, leaping amphibian that is largely aquatic, feeding chiefly on insect larvae, small fishes, and other water dwellers. Their eggs are laid in clusters, enclosed in a gelatinous matrix from which hatch tadpoles, the tailed, gilled larvae that later metamorphose into 4-limbed adults without tails or
gills. Toads are frogs that live on land, although they are still amphibious.

Lizard: a reptile closely related to snakes. Lizards are distinctive from snakes in that they have a fused and inseparable lower jaw, a single temporal opening, two pairs of well differentiated functional limbs, external ears, and eyes with moveable lids. All have scaly skin and replaceable teeth that lack true sockets, fused to the ridge or side of the jaw.

Mammal: A mammal nourishes its young with milk, has skin covered mostly in hair, a mandible articulating directly with the squamosal, a chain of small ear bones, a brain with four optic lobes, a muscular diaphragm separating the heart and lungs from the abdominal cavity, only a left aortic arch, and warm blood containing red cells without nuclei (except in the fetus). Common mammals that live in and around swamps include the opossum, yellow bat, brown bat, nine-banded armadillo, swamp rabbit, marsh rabbit, fox squirrel, flying squirrel, beaver, marsh rice rat, golden mouse,
hispid cotton rat, woodrat, common muskrat, black bear, common raccoon, bobcat, wild boar, white-tailed deer, coyote and red fox.

Salamander: a small amphibian that superficially resembles the lizard, but is scaleless and covered with a soft, moist skin. Salamanders are usually semiterrestrial as adults and live in dark, moist places. However, just like frogs they pass through a larval stage during which they breathe by gills. Salamanders feed on small animals, such as worms and insects.

Snake: any of the numerous scaly, limbless reptiles with a very elongated body. The mandibles are connected in front by an elastic ligament so that the mouth is very distensible, the eyes are permanently covered by a transparent membrane, and there is only one lung. Snakes are predaceous, in the habit of killing their prey by constriction or by injection of venom with hollow, grooved fangs, and then swallow the prey whole. Snakes lack the tympanum of the ear, but can hear (and smell animal breath) with its forked tongue. Nodules behind the ear allow detection of infrared light, sometimes called ‘snake vision’. Snakes lay eggs and give live birth, depending on the species. Common
snakes that live in swamps include the ring-necked snake, corn snake, common kingsnake, rat snake, plain-bellied water snake, water snake, coachwhip snake, ribbon snake, garter snake, copperhead snake (poisonous), cottonmouth snake (poisonous), pygmy rattlesnake (poisonous) and timber rattlesnake (poisonous).

Fungi: These plants lack true chlorophyll and have a body made up of single cells or specialized hyphae. They are often saprophytic or parasitic plants, including molds, mildews, rusts, smuts, mushrooms, toadstools, puffballs, and some yeasts, bacteria and slime molds. Common fungi that live in or around swamps are artist’s fungus, chicken mushroom, destroying angel, meadow mushroom, oyster mushroom, pigskin puffball, ravenel’s stinkhorn, shaggy mane, and witch’s butter.