Liverwort

botanical division containing terrestrial plants without stomata
A liverwort, Lunularia cruciata
Marchantia polymorpha, with different sex sporophytes.

The liverworts are a group of simple plants. Scientists believe that liverworts were the first bryophyte to evolve. They believe that mosses, hornworts, and more complex plants then evolved from liverworts. Scientists decided this from mitochondrial DNA.[1]p75

Liverworts are usually placed in the bryophytes, a group of plants without tissue to conduct water. This group also includes with mosses and hornworts. Recent taxonomy gave them their own division called the Marchantiophyta. However, since the classification is not yet settled, we use the old terms.

Liverworts, as the picture shows, are small plants with flattened bodies, or with flattened stems bearing overlapping scales.[2]p135

ReproductionEdit

Liverworts have a gametophyte-dominant life cycle. This is a type of alternation of generations similar to that of mosses. Cells in a typical liverwort plant are haploid for most of its life cycle. Their stalked sporophytes (diploid) are very short-lived, withering away soon after releasing the spores.

ReferencesEdit

  1. Willis K.J. and McElwain J.C. 2002. The evolution of plants. Oxford.
  2. Schofield W.B. 1985. Introduction to Bryology Macmillan, New York. ISBN 0-02-949660-8.