Book contents
- Frontmatter
- Contents
- Foreword
- Preface
- Acknowledgments
- Part I Introduction to floral diagrams
- Part II Floral diagrams in the major clades
- 4 Systematic significance of floral diagrams
- 5 Basal angiosperms: the ascent of flowers
- 6 Monocots: variation on a trimerous Bauplan
- 7 Early diverging eudicots: a transition between two worlds
- 8 Basal core eudicots: the event of pentamerous flowers
- 9 Caryophyllids: how to reinvent lost petals
- 10 Rosids: the diplostemonous alliance
- 11 Asterids: tubes and pseudanthia
- Part III Conclusions
- References
- Glossary
- Taxonomic index
- Subject index
10 - Rosids: the diplostemonous alliance
Published online by Cambridge University Press: 24 January 2011
- Frontmatter
- Contents
- Foreword
- Preface
- Acknowledgments
- Part I Introduction to floral diagrams
- Part II Floral diagrams in the major clades
- 4 Systematic significance of floral diagrams
- 5 Basal angiosperms: the ascent of flowers
- 6 Monocots: variation on a trimerous Bauplan
- 7 Early diverging eudicots: a transition between two worlds
- 8 Basal core eudicots: the event of pentamerous flowers
- 9 Caryophyllids: how to reinvent lost petals
- 10 Rosids: the diplostemonous alliance
- 11 Asterids: tubes and pseudanthia
- Part III Conclusions
- References
- Glossary
- Taxonomic index
- Subject index
Summary
The rosid clade is a well supported, but the least resolved major clade of core eudicots, containing more than a quarter of all angiosperm species (Schönenberger and von Balthazar,2006). Saxifragales are generally linked with rosids, although support is not high and the order has been associated with caryophyllids (e.g. Soltis et al., 2003). It is clear that Saxifragales represent an ancient early diverging lineage in the core eudicots (Soltis et al., 2005; Magallón, 2007). A recent analysis incorporating a high number of genes has clarified the internal relationships of rosids with the recognition of two main clades, fabids (or Fabidae) and malvids (or Malvidae), and the inclusion of Saxifragales as a basal order and Vitaceae as sister to the rosid clade (Wang et al., 2009). Figure 10.1 represents a phylogenetic tree of the rosids based on Wang et al. (2009).
Saxifragales
Saxifragales sensu APG (2003) comprises an assemblage of highly diverse families (about ten), including core saxifrages and allies and part of the former Hamamelidae of Cronquist (1981) with strongly reduced flowers.
The general flower morphology fits well with the syndrome found in rosids. Flowers tend to be generally pentamerous or tetramerous and share a hypanthium, often with half-inferior ovary. Obdiplostemony is a common feature in families with two whorls of stamens (e.g. Saxifragaceae, Haloragaceae, Crassulaceae: Ronse De Craene and Smets, 1995b). Diplostemony is also reconstructed as the ancestral character state in the Saxifragales by Soltis et al. (2005).
- Type
- Chapter
- Information
- Floral DiagramsAn Aid to Understanding Flower Morphology and Evolution, pp. 193 - 291Publisher: Cambridge University PressPrint publication year: 2010