Ranunculales is an order of flowering plants. Of necessity it contains the family Ranunculaceae, the buttercup family, because the name of the order is based on the name of a genus in that family. Ranunculales belongs to a paraphyletic group known as the basal eudicots. It is the most basal clade in this group; in other words, it is sister to the remaining eudicots.
The Angiosperm Phylogeny Group recognized seven families in Ranunculales in their APG III system, published in 2009. In the preceeding APG II system, they offered the option of three segregate families as shown below.
* order Ranunculales
[+ family Kingdoniaceae ]
[+ family Fumariaceae ]
Note: "+ ..." = optionally separate family (that may be split off from the preceding family).
Under this definition, well-known members of Ranunculales include buttercups, clematis, columbines, delphiniums, and poppies.
The Cronquist system (1981) also recognised the order, but placed it in the subclass Magnoliidae, in class Magnoliopsida [= dicotyledons]. It used this circumscription:
* order Ranunculales
In the Cronquist system, the Papaveraceae and Fumariaceae (including the plants in the optional family Pteridophyllaceae) were treated as a separate order Papaverales, placed in this same subclass Magnoliidae. The Cronquist circumscription of Ranunculales is now known to be polyphyletic. Sabiaceae is in a clade of basal eudicots separate from Ranunculales. Coriariaceae is now placed in the order Cucurbitales.
A phylogeny of Ranunculales was published in 2009, based on molecular phylogenetic analysis of DNA sequences. The authors of this paper revised the subfamilies and tribes of the order.
1. ^ Wei Wang; An-Ming Lu, Yi Ren, Mary E. Endress, and Zhi-Duan Chen (2009). "Phylogeny and Classification of Ranunculales: Evidence from four molecular loci and morphological data". Perspectives in Plant Ecology, Evolution and Systematics 11 (2): 81–110. doi:10.1016/j.ppees.2009.01.001.
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