Hepaticophyta

Hepaticophyta

Liverworts

Barbara Crandall-Stotler, Raymond E. Stotler, and Brian R. Speer *


                         ,===== Jungermanniidae  (leafy liverworts) 
                         |
     ,=Jungermanniopsida=|||||| Metzgeriidae  (simple-thalloid liverworts) 
     |                   |
<<===|                   `===== Calobryales 
     |
     |                 ,======= Sphaerocarpidae 
     `=Marchantiopsida=|
                       `======= Marchantiidae  (complex-thalloid liverworts) 

                           ?=== Protosalvinia

Containing clade(s): Embryophytes

Introduction

Discussion of Phylogenetic Relationships

References

Introduction

There are more than 7000 species of liverworts (Hepaticophyta) alive today, making them a more diverse group than the mammals. Liverworts may be found on every continent and every terrestrial environment on Earth. Despite being such a large and widespread group, liverworts are not familiar to most people. This is in part a result of the diminutive size of most species, and perhaps in part because liverworts do not produce colorful flowers or complex leaves.

Discussion of Phylogenetic Relationships

No detailed and thorough cladistic analysis of basal liverwort relationships has yet been made. Traditional classification schemes divide the liverworts in two fundamental groups which may be distinguished by the development of their antheridia ( ).

The first published studies ( , , , ) assumed each traditional order to be a monophyletic group and scored characters for these orders rather than individual taxa. However, the Metzgeriales is quite likely paraphyletic and the position of Monocleales, consisting solely of the genus Monoclea, is still debated.

Part of the difficulty in performing a morphological analysis is the relative simplicity of liverwort morphology. Few liverwort taxa have complex tissues or complex structural organization, and each major group has a body plan very different from the others. As a result, only fundamental characters of development can be scored across the complete range of liverwort taxa.

References

Grolle, R. 1983. Nomina generica Hepaticarum; references, types 
          and synonymies. Acta Bot. Fennica 121:1-62.
Schuster, R. M. 1992. The Hepaticae and Anthocerotae of North 
          America east of the hundredth meridian, 6 vols.  Field 
          Museum, Chicago.

About this page

Barbara Crandall-Stotler
E-mail: crandall@plant.siu.edu.
Department of Botany, Southern Illinois University, Carbondale, Illinois, USA

Raymond E. Stotler
E-mail: stotler@plant.siu.edu.
Department of Botany, Southern Illinois University, Carbondale, Illinois, USA

Brian R. Speer
E-mail: vespirus@socrates.berkeley.edu.
Museum of Paleontology, University of California, Berkeley, California, USA

Correspondence regarding this page should be directed to Brian R. Speer, at vespirus@socrates.berkeley.edu.

Title Illustrations

From left to right:

Information on the Internet

Hepaticophyta

Liverworts

Table of Contents

Introduction

Discussion of Phylogenetic Relationships

References

About this page

Title Illustrations

Information on the Internet