Re: Why does moss grow?

Why moss grows is a question that scientists do not try to answer. One possible
answer is that moss grows because growth is a characteristic of living organisms. 

Moss is a photosynthetic plant so requires light for growth. It also requires
water and temperatures that are not too cold and not too hot. For example, moss
would not grow when it was dark, its environment was very dry and when
temperatures were below freezing. lack of water is often a major limiting factor
for moss growth. Nonweather factors can be important in moss growth, especially
the supply of essential mineral nutrients.

Aquatic moss growth rates seem to have been studied more than nonaquatic mosses,
probably because they have steadier growth rates because of their constant water
supply. Some aquatic Arctic mosses only grow 1 cm per year because of their
short growing season. Shoots of an aquatic moss (Rhynchostegium riparioidesin)
grew 3.3 to 7.3 cm per year in Northern England. It even grew slightly in the
winter. In Denmark, some aquatic mosses grow up to 25 cm per year.

Moss is a fascinating group of plants that is often very different from the seed
plants that people are more familiar with. In comparison to seed plants, such as
trees, flowers and shrubs,

1. Mosses are often very tolerant of drying out.
2. Mosses do produce seeds, they reproduce by spores.
3. Mosses have no roots to absorb water and mineral nutrients from the soil.
4. Mosses have no vascular tissues (xylem and phloem) that internally transport
water, mineral nutrients and organic compounds.
5. Mosses are considered pioneer plants because they can grow on bare rocks.
They help to form soil.

Other interesting moss facts,
1. Moss gardens are popular, especially in Japan
2. Moss is often considered a weed when it grows in lawns and on roofs.
3. Peat moss is an important source of fuel in Europe and is widely used in
potting soils and as a  soil amendment for gardening in the United States.

References


Amazing Arctic Moss


Cultivation of Mosses


KELLY, M. G. & WHITTON, B. A. 1987. Growth rate of the aquatic moss
Rhynchostegium riparioidesin Northern England.
Freshwater Biology 18 (3), 461-468.


Tenna Riis and Kaj Sand-Jensen 1997. Growth Reconstruction and Photosynthesis of
Aquatic Mosses: Influence of Light, Temperature and Carbon Dioxide at Depth.
Journal of Ecology 85: 359-372.