There are 150 to 300 species of sphagnum moss, also called sphagnum peat moss and peat moss. Sphagnum moss is a living moss. Peat moss is dead sphagnum moss. Sphagnum mosses are ordinarily found in bogs and swamps in cold wet areas of Northern Europe, Canada, the Pacific Northwest and other northern states. These useful mosses can hold up to 20 times their dry weight in water, which is why they are often used to amend soil, as an ingredient in potting mixes, and as a medium in hydroponic growing systems.
Sphagnum moss, which likes cold water, comes together in thick mats in swampy bogs. It has leaves on its stems and on its slender branches. The leaves contain both living cells and dead cells that absorb water, becoming thick and swollen in the process. The leaves are clear, reddish, green or yellowish and are shaped like spears or cups. Sphagnum moss takes in water through the dead cells on its leaves and stems. It has no roots or flowers. Although it gets food through photosynthesis, the moss gets most of its nutrients from the water, in the process crowding out other species.
Sphagnum moss produces capsules filled with spores. When they're dry, the capsules burst, spreading the spores. The moss can also grow from pieces broken off larger plants. The water held by sphagnum moss can't drain, so the plant creates its own habitat. The moss on top is alive. The moss underneath, peat moss, is dead. A mat of sphagnum moss and the underlying sphagnum peat moss can get thick enough to support the weight of a moose.
Capacity to Absorb
Sphagnum moss absorbs moisture from the atmosphere as well as the bog where it lives. It contains a delicate system of capillary tubes. These minute tubes and the spaces around them create a kind of fine sponge. The moss quickly absorbs water and retains it. If it is squeezed dry, the plant takes in more water. The spaces around the tubes help the moss to float, thus keeping the surface facing the sun, necessary for photosynthesis.
From Sphagnum to Coal
The dead peat moss beneath the living sphagnum moss eventually settles and decays, becoming peat. This peat forms thick layers, losing its moisture. It eventually becomes lignite, a soft, brown fuel often used to power electrical generators. The lignite later becomes soft, black bituminous coal, commonly mined in the United States. Even lower and harder to extract is anthracite, a hard coal that burns with little smoke.
Uses of Sphagnum
The extraordinary ability of sphagnum moss to absorb fluids made it useful historically as a surgical dressing. Sphagnum moss is commonly used to line hanging baskets. It is used to hold cuttings and bulbs. It is wrapped around the roots of trees and plants being transported. It is also used for the propagation of orchids, as a medium for hydroponic solutions, and as bedding for reptiles and worms.