name = Asterales
Sunflower, "Helianthus annuus"
image_width = 300px
divisio = Magnoliophyta
ordo = Asterales Lindl. (1833)
subdivision_ranks = Families
Campanulaceae(incl. Lobeliaceae) - Bellflowers
The order is cosmopolitic, and includes mostly herbaceous species, although a small number of trees ("Lobelia") and shrubs is also present.
The Asterales can be characterized on the morphological and molecular level. Synapomorphies include the
oligosaccharide inulinas the nutrients storage, and the stamens are usually aggregated densely around the style or even are fused into a tube around it. The last property is probably associated with the plunger (or secondary) pollination, which is common among the families of the order.
The Asterales include about eleven families, the largest of which are
Asteraceae, with about 25,000 species, and Campanulaceae, with about 2,000 species. The remaining families count together for less than 500 species. The two large families are cosmopolitic with center of mass in the northern hemisphere, and the smaller ones are usually confined to Australia and the adjacent areas, or sometimes South America.
Cronquist system, Asteraceaewas the only family in the group, but newer systems (e. g. APG II) have expanded it.
Evolution and biogeography
The Asterales order probably originated in the
Cretaceouson the supercontinent Gondwana, in the area which is now Australia and Asia. Although most extant species are herbaceous, the examination of the basal families in the order suggests that the common ancestor of the order was an arborescent plant.
Fossil evidence of the Asterales is rare and belongs to rather recent epochs, so the precise estimation of the order's age is quite difficult. An
Oligocenepollen is known for Asteraceae and Goodeniaceae, and seeds from Oligocene and Mioceneare known for Menyanthaceae and Campanulaceae respectively.
(Bremer and Gustafsson, 1997)
The Asteraceae include some species grown for food, including
sunflower("Helianthus annuus"), lettuce("Lactuca sativa") and chicory("Cichorium"). Many spices and medicinal herbs are also present.
Of horticultural importance are the Asteraceae (e. g.
chrysanthemum) and Campanulaceae.
* K. Bremer, M. H. G. Gustafsson (1997). East Gondwana ancestry of the sunflower alliance of families. "Proceedings of the National Academy of Sciences U.S.A." 94, 9188-9190. (Available online: [http://www.pnas.org/cgi/content/abstract/94/17/9188 Abstract] | [http://www.pnas.org/cgi/content/full/94/17/9188 Full text (HTML)] | [http://www.pnas.org/cgi/reprint/94/17/9188.pdf Full text (PDF)] )
* W. S. Judd, C. S. Campbell, E. A. Kellogg, P. F. Stevens, M. J. Donoghue (2002). "Plant Systematics: A Phylogenetic Approach, 2nd edition." pp. 476-486 (Asterales). Sinauer Associates, Sunderland, Massachusetts. ISBN 0-87893-403-0.
* J. Lindley (1833). "Nixus Plantarum", 20. Londini.
* Smissen, R. D. (December 2002). Asterales (Sunflower). In: "Nature Encyclopedia of Life Sciences". Nature Publishing Group, London. (Available online: [http://dx.doi.org/10.1038/npg.els.0003736 DOI] | [http://www.els.net/ ELS site] )
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