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| Proteales | |
|---|---|
 | |
| Protea cynaroides | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Order: | Proteales Juss.exBercht. &J.Presl[1] |
| Families | |
| Synonyms | |
synonymy
| |
Proteales is anorder offlowering plants consisting of three (or four) families. The Proteales have been recognized by almost all taxonomists.
The representatives of the Proteales can be very different from each other due to their very early divergence. They possess seeds with little or noendosperm.The ovules are often atropic.[clarify]
The oldest fossils of Proteales are of thenelumbonaceous genusNotocyamus from theBarremian stage of theEarly Cretaceous ofBrazil,[2] 126–121Ma (million years ago). According tomolecular clock calculations, the lineage that led to Proteales split from other plants about 128 Ma[3] or 125 Ma.[4]
Within the classification system ofRolf Dahlgren, the Proteales were in thesuperorder Proteiflorae, also called Proteanae; TheAPG II system (of 2003) also recognizes this order, placing it in the cladeEudicots, with the following circumscription:
with "+ ..." = optionally separate family (that may be split off from the preceding family).
TheAPG III system of 2009 followed this same approach, but favored the narrower circumscription of the three families, firmly recognizing three families in Proteales: Nelumbonaceae, Platanaceae, and Proteaceae.[1] TheAngiosperm Phylogeny Website, however, suggests the addition ofSabiaceae, which the APG III system did not place in any order in the eudicots, would be sensible.[5]
TheAPG IV system of 2016 added familySabiaceae to the order.[6]
Well-known members of the Proteales include theproteas of South Africa, thebanksia andmacadamia of Australia, theplanetree, and thesacred lotus. The origins of the order are clearly ancient, with evidence of diversification in the mid-Cretaceous, roughly over 100 million years ago. Of notable interest is the family's modern distribution; the Proteaceae is predominantly a Southern Hemisphere family, while the Platanaceae and Nelumbonaceae are Northern Hemisphere plants.
The currentAPG IV classification represents a slight change from theAPG I system of 1998, which firmly did accept family Platanaceae as being separate from the order. Under APG IV, this is the current circumscription of the order:
TheCronquist system of 1981 recognized such an order and placed it in subclassRosidae in classMagnoliopsida [=dicotyledons]. It used this circumscription:
TheDahlgren system andThorne system (1992) recognized such an order and placed it in superorderProteanae in subclassMagnoliidae [=dicotyledons]. TheEngler system, in itsupdate of 1964, also recognized this order and placed it in subclassArchichlamydeae of classDicotyledoneae. TheWettstein system, last revised in 1935, recognized this order and placed it in theMonochlamydeae in subclassChoripetalae of classDicotyledones. These systems used the following circumscription:
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