The liverworts are a group of simple plants. Molecular evidence based on mitochondrial DNA suggests strongly that they are the stem group from which mosses, hornworts and all higher plants evolved.p75
Liverworts are usually regarded as Bryophytes, together with mosses and hornworts. Recent taxonomy places them separately in a division called the Marchantiophyta, or even the Antheroceratophyta. However, since the classification is not yet settled, we keep the old terms for convenience.
Liverworts, as the illustration shows, are small plants with flattened bodies, or with flattened stems bearing overlapping scales or leaves.p135
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 spores.
- Willis K.J. and McElwain J.C. 2002. The evolution of plants. Oxford.
- Schofield W.B. 1985. Introduction to Bryology Macmillan, New York. ISBN 0-02-949660-8.