An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III

TLDR

Recent phylogenetic studies have clarified the placement of many previously unplaced families, leading to the recognition of several new orders such as Amborellales, Berberidopsidales, Bruniales, Buxales, Chloranthales, Escalloniales, Huerteales, Nymphaeales, Paracryphiales, Petrosaviales, Picramniales, Trochodendrales, Vitales, and Zygophyllales. The authors abandoned the use of bracketed families and retained broader circumscriptions for families such as Amaryllidaceae, Asparagaceae, and Xanthorrhoeaceae within Asparagales, Passifloraceae within Malpighiales, Primulaceae within Ericales, and other smaller families. The updated APG III classification incorporates many previously unplaced genera and families into orders, reducing unplaced taxa, and introduces newly segregated families for genera formerly assigned to other APG families, such as Petermanniaceae, Calophyllaceae, Capparaceae, Cleomaceae, and several others.

Abstract

A revised and updated classification for the families of flowering plants is provided. Many recent studies have yielded increasingly detailed evidence for the positions of formerly unplaced families, resulting in a number of newly adopted orders, including Amborellales, Berberidopsidales, Bruniales, Buxales, Chloranthales, Escalloniales, Huerteales, Nymphaeales, Paracryphiales, Petrosaviales, Picramniales, Trochodendrales, Vitales and Zygophyllales. A number of previously unplaced genera and families are included here in orders, greatly reducing the number of unplaced taxa; these include Hydatellaceae (Nymphaeales), Haptanthaceae (Buxales), Peridiscaceae (Saxifragales), Huaceae (Oxalidales), Centroplacaceae and Rafflesiaceae (both Malpighiales), Aphloiaceae, Geissolomataceae and Strasburgeriaceae (all Crossosomatales), Picramniaceae (Picramniales), Dipentodontaceae and Gerrardinaceae (both Huerteales), Cytinaceae (Malvales), Balanophoraceae (Santalales), Mitrastemonaceae (Ericales) and Boraginaceae (now at least known to be a member of lamiid clade). Newly segregated families for genera previously understood to be in other APG-recognized families include Petermanniaceae (Liliales), Calophyllaceae (Malpighiales), Capparaceae and Cleomaceae (both Brassicales), Schoepfiaceae (Santalales), Anacampserotaceae, Limeaceae, Lophiocarpaceae, Montiaceae and Talinaceae (all Caryophyllales) and Linderniaceae and Thomandersiaceae (both Lamiales). Use of bracketed families is abandoned because of its unpopularity, and in most cases the broader circumscriptions are retained; these include Amaryllidaceae, Asparagaceace and Xanthorrheaceae (all Asparagales), Passifloraceae (Malpighiales), Primulaceae (Ericales) and several other smaller families. Separate papers in this same volume deal with a new linear order for APG, subfamilial names that can be used for more accurate communication in Amaryllidaceae s.l., Asparagaceace s.l. and Xanthorrheaceae s.l. (all Asparagales) and a formal supraordinal classification for the flowering plants.