General characters

The mosses and moss alies belong to a single division the Bryophyta.

Fig: Moss

Fig: Moss

This division includes the most primitive of the green land plants. Bryophytes are structurally simple in both morphology and anatomy.

Bryophytes are the most simplest and most primitive land plants
Name bryophyte is derived from two words; ‘Bryon’ = moss; ‘phyton’ = plant. At present the phylum Bryophyta includes  ~ 960 genera and ~ 24000 species.

Habitat:

They are cosmopolitan in distribution

Bryophytes are quite uncommon in marine environments

Bryophytes are terrestrial plants but require water at every stages in their life cycle

They grow usually in moist and shady places

They fail to complete its life cycle in the absence of water

Few bryophytes are truly aquatic and underwater forms(example Riccia fluitans)

Peat moss (Sphagnum moss) grown in bogs and marshy areas

Porella is an epiphytic bryophyte that grow on tree trunks

Radulla protensa is an epiphyllous bryophyte grow on the surface of leaves

Tortula desortorum is a xerophytic bryophyte growing in deserts

Bryophytes are fundamentally land plants

The land adaptations of bryophytes are:

Possess root like rhizoids to absorb water from soil

Free surface of epidermis is coated with water proof waxy coating(Cuticle) to prevent water lose and protect against desiccation

They possess stomata like structures for gaseous exchange

Possess multicellular sex organs surrounded by sterile jacket

After fertilization the zygote is left inside the archegonium to provide nutrition for the sporophyte development

Alternation of Generation also provide genetic recombinations and helps in survival

These features helps bryophytes to live in land condition

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