What are mosses?
Most mosses are small, leafy green plants growing on soil, bark or rock. New Zealand mosses range from 1 millimetre to about half a metre tall.
Where do they grow?
Many grow in damp, shady places such as the forest floor. Some thrive best in full light, and grow high on tree branches or in open areas on soil or rocks. Others live where there is standing water, in swamps and bogs. Silvery bryum thrives in the cracks of city footpaths and buildings, along with several other hardy urban mosses.
The moss life cycle has two different plants. One of these plants produces spores, and it is always attached to the other plant, which produces sex cells (eggs and sperms).
- The leafy plant produces sex cells.
- The other is a spore capsule on a stalk. The spores are released, germinate if conditions are right, and grow into a new generation of plants that produce sex cells.
Some mosses can survive years without water. In dry weather, they shut down their metabolism and stop growing. When the rains return, they start up their metabolism and carry on as if nothing happened.
Mosses in New Zealand
New Zealand has about 550 species of mosses. About one-fifth of them are found nowhere else.
There are three different types:
- sphagnum mosses (peat mosses)
- granite mosses
- true mosses.
Sphagnum moss is valuable to the environment and to New Zealand’s economy. It stores carbon that otherwise could be converted to carbon dioxide, which is a greenhouse gas, and prevents it from rising into the atmosphere and worsening global warming. Some sphagnum is harvested from swamps in Westland and Southland and sold overseas, where it is mostly used to grow orchids. Elsewhere in the world, sphagnum moss is used as fuel and packaging.