Bryophyta

Bryophyta, the division of green plants, refers to embryophytes which in literal terms is land plants, especially the non-vascular ones. This division includes –

  • Mosses – class Bryopsida
  • Liverworts – class Marchantiopsida
  • Hornworts – class Anthocerotopsida

The only prime feature of a bryophyte is that it does not have true vascular tissue. Some do have specialized tissues which is used to transport water but are not considered to be a true vascular tissue due to the lack of lignin.

Bryophytes are believed to evolve from charophytes and are considered to have been the first true plants ever evolved.

Bryophyta

Characteristics of Bryophytes

  • Plants in this category do not have roots but have crude stems and leaves.
  • They have “rhizoids” instead of roots which helps the plant to anchor to surface.
  • These roots or rhizoids do not absorb nutrients like other usual plant roots.
  • Mosses release spores from their leaves which travels by water and make new mosses in new locations.
  • Water is very essential for mosses to grow and spread. They can entirely dry out and survive. When in contact with water, they again revive and continue growing.

Life cycle of Bryophytes are like all the other land plants (embryophytes) with alternation of generations. A haploid gametophyte cell contains a fixed number of unpaired chromosomes. It gives rise to diploid sporophyte, which however contains twice the number of paired chromosomes. Diploid zygotes formed by the fusion of haploid sperm and eggs produced by gametophytes. Diploid zygotes grows into a sporophyte.

Sporophytes’ characteristics of the three groups of bryophytes

Liverworts

Mosses

Hornworts

Capsule form

Simple

Differentiated (operculum, peristome)

Elongated

Columella

Absent

Present

Present

Dehiscence

Longitudinal or irregular

Transverse

Longitudinal

Dispersion of spores

Elaters

Peristome teeth

Pseudo-elaters

Growth

Defined

Defined

Continuous

Maturation of spores

Simultaneous

Simultaneous

Graduate

Persistence

Ephemeral

Persistent

Persistent

Seta

Present

Present

Absent

Stomata

Absent

Present

Present

Structure

Small, without chlorophyll

Large, with chlorophyll

Large, with chlorophyll

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