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The Saxifragales are an order of flowering plants. Their closest relatives are a large eudicot group known as the rosids by the definition of rosids given in the APG II classification system. Some authors define the rosids more widely, including Saxifragales as their most basal group. Saxifragales is one of the eight groups that compose the core eudicots. The others are Gunnerales, Dilleniaceae, rosids, Santalales, Berberidopsidales, Caryophyllales, and asterids.〔Peter F. Stevens. 2001 onwards. "Trees". At: Angiosperm Phylogeny Website At: Missouri Botanical Garden Website. (see ''External links'' below).〕 Saxifragales have an extensive fossil record.〔Elizabeth J. Hermsen, María A. Gandolfo, Kevin C. Nixon, and William L. Crepet. 2006. "The impact of extinct taxa on understanding the early evolution of angiosperm clades: An example incorporating fossil reproductive structures of Saxifragales". ''Plant Systematics and Evolution 260:141–169.〕 The extant members are apparently remnants of a formerly diverse and widespread order.〔Klaus Kubitzki. 2007. "Introduction to Saxifragales". pages 15-18. In: Klaus Kubitski (editor). ''The Families and Genera of Vascular Plants'' volume IX. Springer-Verlag: Berlin;Heidelberg, Germany.〕 The Saxifragales order, as it is now understood, is based upon the results of molecular phylogenetic studies of DNA sequences. It is not part of any of the classification systems based on plant morphology. The group is much in need of comparative anatomical study, especially in light of the recent expansion of the family Peridiscaceae to include ''Medusandra'', a genus that before 2009 had usually not been placed in Saxifragales.〔Kenneth J. Wurdack and Charles C. Davis. 2009. "Malpighiales phylogenetics: Gaining ground on one of the most recalcitrant clades in the angiosperm tree of life." ''American Journal of Botany'' 96(8):1551-1570. (see ''External links'' below)〕 The order is divided into suprafamilial groups as shown on the phylogenetic tree below. These groups are informal and are not understood to have any particular taxonomic rank. == Families == Saxifragales contain about 2470 species.〔Shuguang Jian, Pamela S. Soltis, Matthew A. Gitzendanner, Michael J. Moore, Ruiqi Li, Tory A. Hendry, Yin-Long Qiu, Amit Dhingra, Charles D. Bell, and Douglas E. Soltis. 2008. "Resolving an Ancient, Rapid Radiation in Saxifragales". ''Systematic Biology'' 57(1):38-57. (see ''External links'' below).〕 These are distributed into 15 families,〔 or into 12 families if Haloragaceae ''sensu lato'' is recognized as a family consisting of Haloragaceae ''sensu stricto'', ''Penthorum'', ''Tetracarpaea'', and ''Aphanopetalum''.〔 About 95% of the species are in five families: Crassulaceae (1400), Saxifragaceae (500), Grossulariaceae (150 - 200), Haloragaceae (150), and Hamamelidaceae (100). Most of the families are monogeneric. The number of genera in each family is: *Altingiaceae (3), *Aphanopetalaceae (1), *Cercidiphyllaceae (1), *Crassulaceae (34), *Daphniphyllaceae (1), *Grossulariaceae (1), *Haloragaceae (8), *Hamamelidaceae (27), *Iteaceae (2), *Paeoniaceae (1), *Penthoraceae (1), *Peridiscaceae (4), *Pterostemonaceae (1), and *Saxifragaceae (33), *Tetracarpaeaceae (1). :List source : 〔Peter F. Stevens. 2001 onwards. "Saxifragales" At: Angiosperm Phylogeny Website At: Missouri Botanical Garden Website. (see ''External links'' below).〕 Some authors do not recognize ''Choristylis'' as a separate genus from ''Itea''.〔Klaus Kubitzki. 2007. "Iteaceae". pages 202-204. In: Klaus Kubitski (editor). ''The Families and Genera of Vascular Plants'' volume IX. Springer-Verlag: Berlin;Heidelberg, Germany.〕 Similarly, some authors sink ''Liquidambar'' and ''Semiliquidambar'' into ''Altingia''. Thus Altingiaceae and Iteaceae are monogeneric in some classifications. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Saxifragales」の詳細全文を読む スポンサード リンク
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