Classification of bryophytes:
Bryophytes are classified into three classes as follows:
- Hepaticae (Liverworts)
- Anthoceratae (Hornworts)
- Musci (Mosses)
1. Hepaticae (Liverworts):
- These are the lower form of bryophytes as they are simpler in structures than mosses.
- They are the plants closely related to the ancestor that moved to land, and, hence terrestrial habitat.
- Sporophyte is very simple and short-lived.
Clockwise from top left: Riccia, Marchantia, Pellia and Porella.
2. Anthoceratae (Hornworts):
- These are plants that have colonised various habitats on land, although they are never far from a source of moisture.
- The gametophyte of these plants have an undifferentiated thallus, their rhizoids are unicellular and unbranched.
- Protonemal stage (the first stage that directly develops from the spore) is absent.
- The sporophyte is differentiated into foot and capsule only.
Antheroceros and Notothylas
3. Musci (Mosses):
- These are the bryophytes that live in a variety of environments.
- These are higher forms of bryophytes in which the gametophytes are differentiated into stems, leaf and root-like parts.
- Protonemal stage is present.
- Sporophytes are differentiated into foot, seta, and capsule.
Sphagnum, Funaria and Polytrichum
Economic importance of Mosses
1. Environmental uses:
- They prevent soil erosion by reducing the impact of falling rain.
- They help in recycling the nutrients.
- They act as a rock builder.
2. Peat formation:
Peat which is a valuable fuel like coal. It is obtained from Sphagnum (Hence, known as Peat Moss)
3. In seedbeds and nursery:
Sphagnum has the capability of high water absorption. Hence, it is used by the gardeners in nursery, in seedbeds and in greenhouses.
4. As food:
Some of the mosses serve as food materials for herbaceous mammals, birds and other mammals.