Book contents
- Frontmatter
- Contents
- Contributors
- Preface
- 1 Introduction: islands and plants
- 2 The reproductive biology of island plants
- 3 Spatial methodologies in historical biogeography of islands
- 4 Origin and evolution of Hawaiian endemics: new patterns revealed by molecular phylogenetic studies
- 5 Origins and evolution of Galapagos endemic vascular plants
- 6 The plants of the Caribbean islands: a review of the biogeography, diversity and conservation of a storm-battered biodiversity hotspot
- 7 The biogeography of Madagascar palms
- 8 Evolution and biogeography of the flora of the Socotra archipelago (Yemen)
- 9 Biogeography and conservation of the flora of New Caledonia
- 10 Phytogeography and relationships of the Pitcairn Islands flora
- 11 Chromosomes and evolution in New Zealand endemic angiosperms and gymnosperms
- 12 Jesters, red queens, boomerangs and surfers: a molecular outlook on the diversity of the Canarian endemic flora
- 13 Endemism and evolution in Macaronesian and Mediterranean Limonium taxa
- 14 Dispersal, diversity and evolution of the Macaronesian cryptogamic floras
- 15 Invasive alien species and islands
- 16 Ecology, demography and conservation in the Galapagos Islands flora
- 17 New directions and challenges for the conservation of the flora of Madagascar
- 18 Climate change and island floras
- 19 Conservation status of endemic plants on Isla del Coco, Costa Rica: applying IUCN Red List criteria on a small island
- 20 Botanic gardens and the conservation of island floras
- 21 The hazardous future of island floras
- Index
- References
11 - Chromosomes and evolution in New Zealand endemic angiosperms and gymnosperms
Published online by Cambridge University Press: 07 October 2011
- Frontmatter
- Contents
- Contributors
- Preface
- 1 Introduction: islands and plants
- 2 The reproductive biology of island plants
- 3 Spatial methodologies in historical biogeography of islands
- 4 Origin and evolution of Hawaiian endemics: new patterns revealed by molecular phylogenetic studies
- 5 Origins and evolution of Galapagos endemic vascular plants
- 6 The plants of the Caribbean islands: a review of the biogeography, diversity and conservation of a storm-battered biodiversity hotspot
- 7 The biogeography of Madagascar palms
- 8 Evolution and biogeography of the flora of the Socotra archipelago (Yemen)
- 9 Biogeography and conservation of the flora of New Caledonia
- 10 Phytogeography and relationships of the Pitcairn Islands flora
- 11 Chromosomes and evolution in New Zealand endemic angiosperms and gymnosperms
- 12 Jesters, red queens, boomerangs and surfers: a molecular outlook on the diversity of the Canarian endemic flora
- 13 Endemism and evolution in Macaronesian and Mediterranean Limonium taxa
- 14 Dispersal, diversity and evolution of the Macaronesian cryptogamic floras
- 15 Invasive alien species and islands
- 16 Ecology, demography and conservation in the Galapagos Islands flora
- 17 New directions and challenges for the conservation of the flora of Madagascar
- 18 Climate change and island floras
- 19 Conservation status of endemic plants on Isla del Coco, Costa Rica: applying IUCN Red List criteria on a small island
- 20 Botanic gardens and the conservation of island floras
- 21 The hazardous future of island floras
- Index
- References
Summary
The New Zealand flora, like that of many other oceanic islands, is unique in several ways. It has a high level of endemicity (de Lange et al., 2006) but this is largely at the species level, with approximately 82% (1944/2357) of taxa being endemic. However, only 65 of the 446 indigenous genera are regarded as endemic and there was only one endemic family, the Ixerbaceae, represented by the monogeneric Ixerba brexioides (Fig. 11.1a.b), a small woody tree of northern New Zealand forests, but the family has now been merged with the Strasburgiaceae (APG, 2009). The vascular flora is also remarkably small for an archipelago the size of New Zealand (263 830 km2), in comparison, the much smaller Fijian archipelago (18 235 km2) has an indigenous spermatophyte flora of 1318 taxa in 137 families and 490 genera (Smith, 1996) and, while complete statistics are not available, the even smaller Hawaiian archipelago (16 626 km2) has an indigenous flowering plant flora of c.956 species in 87 families and 216 genera (Wagner et al., 1990). So what makes New Zealand’s flora so unusual? Perhaps the answer lies not so much in the size of the flora and its perceived diversity but rather in the problem of species and generic delimitation. Many New Zealand genera, most notably those that are species rich, either have poorly defined generic boundaries, e.g. Celmisia, Raoulia (Allan, 1961; Ward, 1997; Cross et al., 2002; Smissen et al., 2004), or hybridise readily, especially in situations of prolonged disturbance, e.g. Chionochloa, Coprosma, Epilobium and Kunzea (Oliver, 1935; Connor, 1967; Raven & Raven, 1976; Wichman et al., 2002; de Lange et al., 2005). Hybridism is a feature of the New Zealand flora and it occurs at both the species and genus level to varying degrees but at sufficient frequency to ensure that the existence of hybrids has caused difficulties with traditional taxonomic attempts to classify the flora (Morgan-Richards et al., 2009). This recognition of hybridism in the New Zealand flora is not a recent discovery; indeed, early New Zealand botanical writings indicate an awareness of hybrids as early as the mid 1860s and it was certainly postulated as both a driver for speciation and a feature of the indigenous flora by pioneering botanists such as Leonard Cockayne and Harry Allan (Cockayne, 1923, 1929; Allan, 1924; Cockayne & Allan, 1934). Although the prevalence of widespread hybridism has been questioned (Allan, 1961; Hair, 1966; Connor, 1985), its significance has come in for re-evaluation (Morgan-Richards et al., 2009), especially with the advent of DNA-based methods when many examples have been confirmed (Molloy & Dawson, 1998; Lockhart et al., 2001; Wichman et al., 2002; Gardner et al., 2004; Murray et al., 2004; de Lange et al., 2008).
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- The Biology of Island Floras , pp. 265 - 283Publisher: Cambridge University PressPrint publication year: 2011
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