Sphagnum is a
genus of approximately 120
species of
mosses, commonly known as
peat moss. Accumulations of
Sphagnum can store water, since both living and dead plants can hold large quantities of water inside their cells; plants may hold 16–26 times as much water as their dry weight, depending on the species. The empty cells help retain water in drier conditions. Hence, as sphagnum moss grows, it can slowly spread into drier conditions, forming larger
mires, both raised
bogs and
blanket bogs. These
peat accumulations then provide habitat for a wide array of peatland plants, including sedges and
ericaceous shrubs, as well as orchids and carnivorous plants.
Sphagnum and the
peat formed from it do not decay readily because of the
phenolic compounds embedded in the moss's
cell walls. In addition, bogs, like all wetlands, develop anaerobic soil conditions, which produces slower
anaerobic decay rather than aerobic microbial action. Peat moss can also acidify its surroundings by taking up
cations, such as
calcium and
magnesium, and releasing
hydrogen ions. Under the right conditions, peat can accumulate to a depth of many meters. Different species of
Sphagnum have different tolerance limits for flooding and pH, so any one peatland may have a number of different
Sphagnum species.
