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
11 - Asterids: tubes and pseudanthia
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
Asterids are subdivided into two main groupings: basal asterids (a grade) consisting of Cornales and Ericales, and euasterids (with Lamiids and Campanulids) (Figs. 11.1, 11.2; e.g. Judd and Olmstead, 2004). Spichiger et al. (2002) distinguished between archaic asterids, superior hypogynous asterids and superior epigynous asterids.
Characters common in a majority of taxa of asterids are sympetaly with adnate stamens (stamen-petal tube), unitegmic, tenuinucellate ovules, cellular endosperm formation, terminal endosperm haustoria, pollen that is released at the trinucleate stage, and the presence of iridoids (e.g. Judd and Olmstead, 2004; Soltis et al., 2005). Apart from sympetaly, the other characters cannot be used in floral diagrams.
Most taxa share the development of a ring primordium in early stages of development (Erbar, 1991) indicating a generalized syndrome of petal development (see p. 34).
Core asterids (euasterids) share sympetaly, a bicarpellate gynoecium and haplostemony, while the basal orders Cornales and Ericales are much more variable with a basically diplostemonous androecium.
Basal asterids: Cornales, Ericales
Cornales
The basalmost order of asterids (Fig. 11.2) contains six to seven families, with three main families Hydrangeaceae, Cornaceae and Loasaceae. All share small sepals, an inferior ovary, epigynous disc nectary, and often drupaceous fruits (Soltis et al., 2005). Soltis et al. (2005) argued that the half-inferior ovary of Hydrangeaceae evolved from epigyny common in the clade. Most Cornales have free petals, with the evolution of a corolla tube in a few Loasaceae.
- Type
- Chapter
- Information
- Floral DiagramsAn Aid to Understanding Flower Morphology and Evolution, pp. 292 - 348Publisher: Cambridge University PressPrint publication year: 2010