The
Angiosperm Phylogeny Group recognized seven families in Ranunculales in their
APG III system,
published in 2009. In the preceding
APG II system, they offered the option of three
segregate families as shown below. • order Ranunculales • : family
Berberidaceae • : family
Circaeasteraceae • :: [+ family
Kingdoniaceae ] • : family
Eupteleaceae • : family
Lardizabalaceae • : family
Menispermaceae • : family
Papaveraceae • :: [+ family
Fumariaceae ] • :: [+ family
Pteridophyllaceae ] • : family
Ranunculaceae 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. 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. This is reflected in the subsequent revision of the APG, APG IV (2016). The analysis revealed that the order consisted of three
clades, Eupteleaceae, Papaveraceae and a third clade, considered to be the "core" Ranuculales, consisting of the remaining five families. The phylogeny of the families is shown in the
cladogram. }} }} }}
Evolution The fossil form
Leefructus, described in 2011, has been recognized as a member of this order.
Leefructus mirus shows fully developed leaves; stem and flower that are very similar in structure to those of the modern
buttercups. The fossil is dated to 125
Mya (
million years old) and it not only proves that Ranunculales is an ancient group of
eudicots but demonstrates that the whole
angiosperm clade may be older than expected. The structure of the plant and its age may lead to a new approach regarding the field that studies the evolution of
flowering plants. The fact that
Leefructus shows a well-developed structure similar to modern ranunculids suggests that this group of eudicots may have developed earlier than the age of the fossil. Another fossil has been described with the name
Teixeiraea, also from the
Cretaceous of
Portugal. The genus
Atli from the
Late Cretaceous of Canada appears to have had a
liana-like growth habit. According to
molecular clock calculations, the lineage that led to Ranunculales split from other plants about 132
Mya or 140 Mya. ==History==