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CABI Book Chapter

Cycad classification: concepts and recommendations.

Book cover for Cycad classification: concepts and recommendations.

Description

This book presents the current state of our knowledge of the systematics of the approximately 300 species of cycads. It has been developed from 15 papers presented at the conference in Miami. Guidelines are presented for the designation of species, species boundaries and species groupings, thus clarifying what has been a confused area of research. Two appendices are included in this volume. The fi...

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Chapter 3 (Page no: 23)

Character evolution, species recognition and classification concepts in the Cycadaceae.

A number of systems of infrageneric classification of the family Cycadaceae have been presented by different authors. No two systems have been the same in structure or species recognition, and some have been strikingly discordant. Phylogenetic analysis of combined morphological and molecular datasets has yielded a cladogram with good resolution and support on many deeper branches. Plotting characters used by different authors in developing infrageneric systems of classification allows an independent assessment of the value of these characters and of the systems of classification derived from them. No classification system presented to date is wholly concordant with the results of the phylogenetic studies, and a number of characters previously heavily relied upon in defining groups are shown to be highly plastic. In particular, the recently described segregate genus Epicycas is shown to be polyphyletic, as are the four subgenera of Cycas erected by the same authors. The analysis supports the recognition of a single genus with five sections, although a number of taxa are insufficiently known to be clearly placed. Species recognition and species concepts are discussed.

Other chapters from this book

Chapter: 1 (Page no: 1) 'We Hold these Truths ...'. Author(s): Walters, T. Osborne, R. Decker, D.
Chapter: 2 (Page no: 13) Saving ghosts? The implications of taxonomic uncertainty and shifting infrageneric concepts in the cycadales for red listing and conservation planning. Author(s): Donaldson, J.
Chapter: 4 (Page no: 45) Morphological characters useful in determining species boundaries in Cycas (Cycadaceae). Author(s): Lindström, A.
Chapter: 5 (Page no: 57) Comments on Cycas, Dyerocycas and Epicycas (Cycadaceae). Author(s): Chen ChiaJui Hill, K. D. Stevenson, D. W.
Chapter: 6 (Page no: 69) Classification concepts in Encephalartos (Zamiaceae). Author(s): Vorster, P.
Chapter: 7 (Page no: 85) Classification concepts in Macrozamia (Zamiaceae) from Eastern Australia. Author(s): Forster, P. I.
Chapter: 8 (Page no: 95) Classification concepts in Ceratozamia (Zamiaceae). Author(s): Whitelock, L. M.
Chapter: 9 (Page no: 109) Relationships and phytogeography in Ceratozamia (Zamiaceae). Author(s): Vovides, A. P. Pérez-Farrera, M. A. González, D. Avendaño, S.
Chapter: 10 (Page no: 127) A morphometric analysis of the Ceratozamia norstogii complex (Zamiaceae). Author(s): Pérez-Farrera, M. A. Vovides, A. P. Hernández-Sandoval, L. González, D. Martínez, M.
Chapter: 11 (Page no: 137) Hypotheses on the relationship between biogeography and speciation in Dioon (Zamiaceae). Author(s): Gregory, T. J. Chemnick, J.
Chapter: 12 (Page no: 149) Molecular phylogeny of Zamia (Zamiaceae). Author(s): Caputo, P. Cozzolino, S. Luca, P. de Moretti, A. Stevenson, D. W.
Chapter: 13 (Page no: 159) Systematics of Meso-American Zamia (Zamiaceae). Author(s): Schutzman, B.
Chapter: 14 (Page no: 173) Zamiaceae of Bolivia, Ecuador and Peru. Author(s): Stevenson, D. W.
Chapter: 15 (Page no: 195) In search of the true tree: guidelines for classification. Author(s): Osborne, R. Walters, T.

Chapter details

  • Author Affiliation
  • Royal Botanic Gardens, Mrs Macquaries Road, Sydney 2000, Australia.
  • Year of Publication
  • 2004
  • ISBN
  • 9780851997414
  • Record Number
  • 20043021927