Sphagnum Mosses (Peat Mosses)

Sphagnum moss with fingers in upper left corner
Scientific Name
Sphagnum spp.
Sphagnaceae (sphagnum or peat mosses)

Sphagnums, or peat mosses, are a large group of shaggy-looking, moisture-loving mosses that range from light green to bright green and often have a pink, purple, red, or brown cast. Missouri has about 18 species in genus Sphagnum. Due to their unusual growth habit, they are neither carpet (pleurocarpous) nor cushion (acrocarpous) mosses.

Sphagnum mosses branch profusely in a spiral about the upright stems. The branches usually spread away from the main stem and curve back on themselves. The branches occur in groups called fascicles and are frequently densely clustered and crowded toward the tip of the stem. Overall, they have a shaggy, unkempt appearance.

As the top portion of a sphagnum moss continues to grow, the lower part dies off, turning from green to tan to dark brown. Accumulations of this material are called peat. In cooler regions, and over thousands of years, the peat builds up and creates deposits; the wetlands associated with these are called peat bogs.

The capsules of sphagnums are spherical, dark brown or black, and have short stalks. They violently expel their spores at distances of up to 4 inches.

Learn more about Missouri’s mosses on their group page.

Other Common Names
Bog Moss

Width: varies with species; colonies of sphagnum mosses can potentially cover large areas in suitable wet locations.

Where To Find

Statewide. Different species may be more or less common in different regions.

Sphagnums are strongly associated with wetlands, wet, seepy rock ledges, seepage areas at springs, moist gullies, and sandy creek banks. Rather acidic, sandy soils and sandstone substrates seem the most common places in our state for sphagnum mosses.

Sphagnums require a very moist, humid habitat. If they are removed from their habitat and dry out, they become very white and enter a period of dormancy.

Sphagnums are a characteristic plant of Missouri’s sinkhole flatwoods and acid seeps natural communities.

Approximately 15 of Missouri’s 18 species in genus Sphagnum are species of conservation concern in our state. This means that they are rare or for some other reason considered at risk of being extirpated from within our state.

Life Cycle

As with other mosses, sphagnums have alternating generations. The plant we usually think of as the moss is the gametophyte generation (it’s a gamete-, or sex-cell-bearing plant). In separate organs, it produces sperm and eggs. When water, even a thin layer of rainwater, is present, the sperm can swim to the eggs and fertilization occurs.

The resulting offspring plant, called a sporophyte (spore-bearing plant), grows out of the female organs of the gametophyte. In sphagnum mosses, the sporophyte takes the form of a black or dark brown, globe-shaped capsule growing from the tip of a short stalk. It obtains nutrients from the gametophyte. When mature, the capsule opens to release spores, which can grow into new gametophyte plants.

Mosses also commonly reproduce asexually when portions of the plant break away, get moved elsewhere, and continue growing as separate plants.

Worldwide, sphagnum moss and peat (the brown, dead biomass of sphagnums) have had incredible importance for humans:

  • People have used highly absorbent peat moss for diapers and crib linings.
  • During World War I, when cotton was in short supply, peat moss was used for bandages. Although more difficult to use, it was more absorbent than cotton and had natural antibiotic qualities that fought infection.
  • When used as a soil amendment, peat or other dried mosses can improve the ability of sandy soils to hold moisture. When added to clay, they lighten the soil, improving aeration and drainage.
  • Probably the most significant economic use of any mosses today is the use of peat moss — from ancient, condensed deposits of peat and other plants that have formed over thousands of years in boglands — for fuel in many parts of the world. Estimated to be a billion-dollar industry, the rate of extraction far exceeds its regeneration; thus, like coal, it is nonrenewable. Since peat is a major global carbon sink (it traps vast amounts of carbon dioxide within its chemical structure underground), burning it and releasing the carbon dioxide back into the atmosphere contributes to climate change. Human-caused climate change is creating many problems both for people and for the environment.
  • Whiskey distillers in Scotland dry their malted barley using peat fires. This gives the resulting liquor a strong smoky flavor that is usually described as peaty.
  • More than 100 mummified human bodies have been found in peat bogs, where the acidic water, low oxygen, and cold temperatures naturally preserved their bodies to a remarkable degree. The oldest of these so-called bog people lived 8,000 years before the time of Christ; most seem to be from the Iron Age.
  • J.R.R. Tolkien fans might recognize images of peat bogs from the Lord of the Rings movies. The filmmakers used footage of Kepler Mire, a peat wetland in New Zealand, to depict Tolkein’s fictional Dead Marshes. Tolkein’s frightful wetlands might have been partly inspired by the then-recent discovery of preserved bog-people bodies in Denmark, as well as by the horrors he witnessed during World War I.

In regions where large amounts of sphagnums have grown for thousands of years and formed peat bogs and peat deposits, it’s hard to exaggerate the importance of these plants in their environment. The availability of peat deposits to be used as fuel has undoubtedly influenced human settlement patterns, which in turn have their own profound effects on the environment.

The presence of peat in a body of water tends to soften and acidify the water, adding tannins that give a brown cast to the clear water, like tea. These aspects of water chemistry determine what kinds of plants and animals can survive in peat bogs and other such places. The types of plants and animals that live in a given place define its natural community. In the same way oaks and hickories define many of Missouri’s woodland communities, sphagnum/peat mosses define the wetlands they dominate.

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Similar Species
About Mosses, Liverworts, and Lichens in Missouri

Mosses, liverworts, hornworts, and lichens seem rather similar, but these organisms are in very different groups. Mosses, liverworts, and hornworts are small, low plants usually found in damp habitats. Unlike more familiar plants, they lack veinlike structures and do not produce flowers or seeds — instead, they produce spores. Meanwhile, lichens are not plants at all: they are a collection of different fungi that have photosynthetic algae living within their tissues.

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