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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...

Chapter 6 (Page no: 69)

Classification concepts in Encephalartos (Zamiaceae).

Much progress has been made towards recognizing and circumscribing species of Encephalartos, and currently 65 species plus two subspecies are recognized. Some of the characteristics used for circumscription of species could be used to construct a phylogenetic tree, but others have merely diagnostic value. When constructing a phylogenetic tree, it is essential to keep in mind basic biological principles concerning reproductive behaviour, isolation and geographical distribution, because the first two especially are key factors in evolution. The following evidence is available for phylogenetic reconstruction: vegetative morphology, morphology of reproductive structures, pollen morphology, leaflet anatomy, chromosome number and morphology, chemical characteristics, isoenzyme profiles, DNA analyses and geographical information.

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: 3 (Page no: 23) Character evolution, species recognition and classification concepts in the Cycadaceae. Author(s): Hill, K. D.
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: 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
  • Botany Department, University of Stellenbosch, Private Bag X1, Matieland 7602, Stellenbosch, South Africa.
  • Year of Publication
  • 2004
  • ISBN
  • 0851997414
  • Record Number
  • 20043021930