Question

Name the three main classes of Bryophytes

Answer 1

Hint: Bryophytes ate the first land plants. It is believed that they originated from the aquatic plants and they come on land through water as they are having many similar characteristics to aquatic plants.The main plant body of bryophytes is haploid (gametophytic) on which the sex organs are formed. The new daughter plant body formed is diploid (sporophytic).

Complete step by step answer:
Bryophytes are divided into three main classes -
-Hepaticopsida
-Anthocerotopsida
-Bryopsida
Hepaticopsida are also called liverworts as their main plant body is liver-like. In liver worts , asexual reproduction is performed by formation of specialized structures called gemmae (multicellular asexual buds developed on cup like structures)
Anthocerotopsida are also called Hornworts . Their main plant body is thallus like. The basal part of the hornworts body is having an actively dividing tissue called meristem due to which it grows like the horn of the animal.
Bryopsida are also called Mosses . The plant body of mosses are made of stem like , root like and leaf like structures. Vegetative reproduction in mosses is by fragmentation and budding in the secondary protonema . During sexual reproduction sex organs are produced at the apex of leafy shoots.
The common examples are -
-Hepaticopsida / Liverworts - Marchantia , Riccia etc.
Anthocerotopsida / Hornworts - Anthoceros , Notothylas etc.
Bryopsida / Mosses - funaria , sphagnum etc.

Note:
Protonema is a multicellular filamentous structure formed after the germination of spores in bryophytes. Then the formation of bud takes place on protonema (budding).
In bryophytes the sporophyte (daughter plant body) is dependent on the gametophyte (main plant body). This is a unique character of bryophytes.
The sporophyte of Riccia is the simplest among all the bryophytes.
The sporophyte of anthocerotopsida and mosses is not completely dependent on the gametophyte.
A fossil fuel can be obtained from sphagnum (also called peat moss).