APG system

The APG system (Angiosperm Phylogeny Group system) of plant classification is the first version of a modern, mostly molecular-based, system of plant taxonomy. Published in 1998 by the Angiosperm Phylogeny Group, it was replaced by the improved APG II in 2003, APG III system in 2009 and APG IV system in 2016.

History
The original APG system is unusual in being based, not on total evidence, but on the cladistic analysis of the DNA sequences of three genes, two chloroplast genes and one gene coding for ribosomes. Although based on molecular evidence only, its constituent groups prove to be supported by other evidence as well, for example pollen morphology supports the split between the eudicots and the rest of the former dicotyledons.

The system is rather controversial in its decisions at the family level, splitting a number of long-established families and submerging some other families. It also is unusual in not using botanical names above the level of order, that is, an order is the highest rank that will have a formal botanical name in this system. Higher groups are defined only as clades, with names such as monocots, eudicots, rosids, asterids.

The APG system was superseded in 2003 by a revision, the APG II system, in 2009 by a next revision, the APG III system, and then in 2016 by a further revision, the APG IV system.

Groups
The main groups in the system (all unranked clades) are:


 * angiosperms :
 * monocots
 * commelinoids
 * eudicots
 * core eudicots
 * rosids
 * eurosids I
 * eurosids II
 * asterids
 * euasterids I
 * euasterids II

The APG system recognises 462 families and 40 orders: these are assigned as follows. In the beginning of each listing some families or orders that are not placed in a further clade:


 * clade angiosperms
 * family Amborellaceae
 * family Austrobaileyaceae
 * family Canellaceae
 * family Chloranthaceae
 * family Hydnoraceae
 * family Illiciaceae
 * family Nymphaeaceae [+ family Cabombaceae]
 * family Rafflesiaceae
 * family Schisandraceae
 * family Trimeniaceae
 * family Winteraceae
 * order Ceratophyllales
 * family Ceratophyllaceae
 * order Laurales
 * family Atherospermataceae
 * family Calycanthaceae
 * family Gomortegaceae
 * family Hernandiaceae
 * family Lauraceae
 * family Monimiaceae
 * family Siparunaceae
 * order Magnoliales
 * family Annonaceae
 * family Degeneriaceae
 * family Eupomatiaceae
 * family Himantandraceae
 * family Magnoliaceae
 * family Myristicaceae
 * order Piperales
 * family Aristolochiaceae
 * family Lactoridaceae
 * family Piperaceae
 * family Saururaceae
 * clade monocots
 * family Corsiaceae
 * family Japonoliriaceae
 * family Nartheciaceae
 * family Petrosaviaceae
 * family Triuridaceae
 * order Acorales
 * family Acoraceae
 * order Alismatales
 * family Alismataceae
 * family Aponogetonaceae
 * family Araceae
 * family Butomaceae
 * family Cymodoceaceae
 * family Hydrocharitaceae
 * family Juncaginaceae
 * family Limnocharitaceae
 * family Posidoniaceae
 * family Potamogetonaceae
 * family Ruppiaceae
 * family Scheuchzeriaceae
 * family Tofieldiaceae
 * family Zosteraceae
 * order Asparagales
 * family Agapanthaceae
 * family Agavaceae
 * family Alliaceae
 * family Amaryllidaceae
 * family Anemarrhenaceae
 * family Anthericaceae
 * family Aphyllanthaceae
 * family Asparagaceae
 * family Asphodelaceae
 * family Asteliaceae
 * family Behniaceae
 * family Blandfordiaceae
 * family Boryaceae
 * family Convallariaceae
 * family Doryanthaceae
 * family Hemerocallidaceae
 * family Herreriaceae
 * family Hesperocallidaceae
 * family Hyacinthaceae
 * family Hypoxidaceae
 * family Iridaceae
 * family Ixioliriaceae
 * family Lanariaceae
 * family Laxmanniaceae
 * family Orchidaceae
 * family Tecophilaeaceae
 * family Themidaceae
 * family Xanthorrhoeaceae
 * family Xeronemataceae
 * order Dioscoreales
 * family Burmanniaceae
 * family Dioscoreaceae
 * family Taccaceae
 * family Thismiaceae
 * family Trichopodaceae
 * order Liliales
 * family Alstroemeriaceae
 * family Campynemataceae
 * family Colchicaceae
 * family Liliaceae
 * family Luzuriagaceae
 * family Melanthiaceae
 * family Philesiaceae
 * family Ripogonaceae
 * family Smilacaceae
 * order Pandanales
 * family Cyclanthaceae
 * family Pandanaceae
 * family Stemonaceae
 * family Velloziaceae
 * clade commelinoids
 * family Abolbodaceae
 * family Bromeliaceae
 * family Dasypogonaceae
 * family Hanguanaceae
 * family Mayacaceae
 * family Rapateaceae
 * order Arecales
 * family Arecaceae
 * order Commelinales
 * family Commelinaceae
 * family Haemodoraceae
 * family Philydraceae
 * family Pontederiaceae
 * order Poales
 * family Anarthriaceae
 * family Centrolepidaceae
 * family Cyperaceae
 * family Ecdeiocoleaceae
 * family Eriocaulaceae
 * family Flagellariaceae
 * family Hydatellaceae
 * family Joinvilleaceae
 * family Juncaceae
 * family Poaceae
 * family Prioniaceae
 * family Restionaceae
 * family Sparganiaceae
 * family Thurniaceae
 * family Typhaceae
 * family Xyridaceae
 * order Zingiberales
 * family Cannaceae
 * family Costaceae
 * family Heliconiaceae
 * family Lowiaceae
 * family Marantaceae
 * family Musaceae
 * family Strelitziaceae
 * family Zingiberaceae
 * clade eudicots
 * family Buxaceae
 * family Didymelaceae
 * family Sabiaceae
 * family Trochodendraceae [+ family Tetracentraceae]
 * order Proteales
 * family Nelumbonaceae
 * family Platanaceae
 * family Proteaceae
 * order Ranunculales
 * family Berberidaceae
 * family Circaeasteraceae [+ family Kingdoniaceae]
 * family Eupteleaceae
 * family Lardizabalaceae
 * family Menispermaceae
 * family Papaveraceae [+ family Fumariaceae and family Pteridophyllaceae]
 * family Ranunculaceae
 * clade core eudicots
 * family Aextoxicaceae
 * family Berberidopsidaceae
 * family Dilleniaceae
 * family Gunneraceae
 * family Myrothamnaceae
 * family Vitaceae
 * order Caryophyllales
 * family Achatocarpaceae
 * family Aizoaceae
 * family Amaranthaceae
 * family Ancistrocladaceae
 * family Asteropeiaceae
 * family Basellaceae
 * family Cactaceae
 * family Caryophyllaceae
 * family Didiereaceae
 * family Dioncophyllaceae
 * family Droseraceae
 * family Drosophyllaceae
 * family Frankeniaceae
 * family Molluginaceae
 * family Nepenthaceae
 * family Nyctaginaceae
 * family Physenaceae
 * family Phytolaccaceae
 * family Plumbaginaceae
 * family Polygonaceae
 * family Portulacaceae
 * family Rhabdodendraceae
 * family Sarcobataceae
 * family Simmondsiaceae
 * family Stegnospermataceae
 * family Tamaricaceae
 * order Santalales
 * family Olacaceae
 * family Opiliaceae
 * family Loranthaceae
 * family Misodendraceae
 * family Santalaceae
 * order Saxifragales
 * family Altingiaceae
 * family Cercidiphyllaceae
 * family Crassulaceae
 * family Daphniphyllaceae
 * family Grossulariaceae
 * family Haloragaceae
 * family Hamamelidaceae
 * family Iteaceae
 * family Paeoniaceae
 * family Penthoraceae
 * family Pterostemonaceae
 * family Saxifragaceae
 * family Tetracarpaeaceae
 * clade rosids
 * family Aphloiaceae
 * family Crossosomataceae
 * family Ixerbaceae
 * family Krameriaceae
 * family Picramniaceae
 * family Podostemaceae
 * family Stachyuraceae
 * family Staphyleaceae
 * family Tristichaceae
 * family Zygophyllaceae
 * order Geraniales
 * family Francoaceae
 * family Geraniaceae [+ family Hypseocharitaceae]
 * family Greyiaceae
 * family Ledocarpaceae
 * family Melianthaceae
 * family Vivianiaceae
 * clade eurosids I
 * family Celastraceae
 * family Huaceae
 * family Parnassiaceae [+ family Lepuropetalaceae]
 * family Stackhousiaceae
 * order Cucurbitales
 * family Anisophylleaceae
 * family Begoniaceae
 * family Coriariaceae
 * family Corynocarpaceae
 * family Cucurbitaceae
 * family Datiscaceae
 * family Tetramelaceae
 * order Fabales
 * family Fabaceae
 * family Polygalaceae
 * family Quillajaceae
 * family Surianaceae
 * order Fagales
 * family Betulaceae
 * family Casuarinaceae
 * family Fagaceae
 * family Juglandaceae
 * family Myricaceae
 * family Nothofagaceae
 * family Rhoipteleaceae
 * family Ticodendraceae
 * order Malpighiales
 * family Achariaceae
 * family Balanopaceae
 * family Caryocaraceae
 * family Chrysobalanaceae
 * family Clusiaceae
 * family Dichapetalaceae
 * family Erythroxylaceae
 * family Euphorbiaceae
 * family Euphroniaceae
 * family Flacourtiaceae
 * family Goupiaceae
 * family Hugoniaceae
 * family Humiriaceae
 * family Irvingiaceae
 * family Ixonanthaceae
 * family Lacistemaceae
 * family Linaceae
 * family Malesherbiaceae
 * family Malpighiaceae
 * family Medusagynaceae
 * family Ochnaceae
 * family Pandaceae
 * family Passifloraceae
 * family Putranjivaceae
 * family Quiinaceae
 * family Rhizophoraceae
 * family Salicaceae
 * family Scyphostegiaceae
 * family Trigoniaceae
 * family Turneraceae
 * family Violaceae
 * order Oxalidales
 * family Cephalotaceae
 * family Connaraceae
 * family Cunoniaceae
 * family Elaeocarpaceae
 * family Oxalidaceae
 * family Tremandraceae
 * order Rosales
 * family Barbeyaceae
 * family Cannabaceae
 * family Cecropiaceae
 * family Celtidaceae
 * family Dirachmaceae
 * family Elaeagnaceae
 * family Moraceae
 * family Rhamnaceae
 * family Rosaceae
 * family Ulmaceae
 * family Urticaceae
 * clade eurosids II
 * family Tapisciaceae
 * order Brassicales
 * family Akaniaceae [+ family Bretschneideraceae]
 * family Bataceae
 * family Brassicaceae
 * family Caricaceae
 * family Emblingiaceae
 * family Gyrostemonaceae
 * family Koeberliniaceae
 * family Limnanthaceae
 * family Moringaceae
 * family Pentadiplandraceae
 * family Resedaceae
 * family Salvadoraceae
 * family Setchellanthaceae
 * family Tovariaceae
 * family Tropaeolaceae
 * order Malvales
 * family Bixaceae [+ family Diegodendraceae]
 * family Cistaceae
 * family Cochlospermaceae
 * family Dipterocarpaceae
 * family Malvaceae
 * family Muntingiaceae
 * family Neuradaceae
 * family Sarcolaenaceae
 * family Sphaerosepalaceae
 * family Thymelaeaceae
 * order Myrtales
 * family Alzateaceae
 * family Combretaceae
 * family Crypteroniaceae
 * family Heteropyxidaceae
 * family Lythraceae
 * family Melastomataceae
 * family Memecylaceae
 * family Myrtaceae
 * family Oliniaceae
 * family Onagraceae
 * family Penaeaceae
 * family Psiloxylaceae
 * family Rhynchocalycaceae
 * family Vochysiaceae
 * order Sapindales
 * family Anacardiaceae
 * family Biebersteiniaceae
 * family Burseraceae
 * family Kirkiaceae
 * family Meliaceae
 * family Nitrariaceae [+ family Peganaceae]
 * family Rutaceae
 * family Sapindaceae
 * family Simaroubaceae
 * clade asterids
 * order Cornales
 * family Cornaceae [+ family Nyssaceae]
 * family Grubbiaceae
 * family Hydrangeaceae
 * family Hydrostachyaceae
 * family Loasaceae
 * order Ericales
 * family Actinidiaceae
 * family Balsaminaceae
 * family Clethraceae
 * family Cyrillaceae
 * family Diapensiaceae
 * family Ebenaceae
 * family Ericaceae
 * family Fouquieriaceae
 * family Halesiaceae
 * family Lecythidaceae
 * family Marcgraviaceae
 * family Myrsinaceae
 * family Pellicieraceae
 * family Polemoniaceae
 * family Primulaceae
 * family Roridulaceae
 * family Sapotaceae
 * family Sarraceniaceae
 * family Styracaceae
 * family Symplocaceae
 * family Ternstroemiaceae
 * family Tetrameristaceae
 * family Theaceae
 * family Theophrastaceae
 * clade euasterids I
 * family Boraginaceae
 * family Plocospermataceae
 * family Vahliaceae
 * order Garryales
 * family Aucubaceae
 * family Eucommiaceae
 * family Garryaceae
 * family Oncothecaceae
 * order Gentianales
 * family Apocynaceae
 * family Gelsemiaceae
 * family Gentianaceae
 * family Loganiaceae
 * family Rubiaceae
 * order Lamiales
 * family Acanthaceae
 * family Avicenniaceae
 * family Bignoniaceae
 * family Buddlejaceae
 * family Byblidaceae
 * family Cyclocheilaceae
 * family Gesneriaceae
 * family Lamiaceae
 * family Lentibulariaceae
 * family Myoporaceae
 * family Oleaceae
 * family Orobanchaceae
 * family Paulowniaceae
 * family Pedaliaceae [+ family Martyniaceae]
 * family Phrymaceae
 * family Plantaginaceae
 * family Schlegeliaceae
 * family Scrophulariaceae
 * family Stilbaceae
 * family Tetrachondraceae
 * family Verbenaceae
 * order Solanales
 * family Convolvulaceae
 * family Hydroleaceae
 * family Montiniaceae
 * family Solanaceae
 * family Sphenocleaceae
 * clade euasterids II
 * family Adoxaceae
 * family Bruniaceae
 * family Carlemanniaceae
 * family Columelliaceae [+ family Desfontainiaceae]
 * family Eremosynaceae
 * family Escalloniaceae
 * family Icacinaceae
 * family Polyosmaceae
 * family Sphenostemonaceae
 * family Tribelaceae
 * order Apiales
 * family Apiaceae
 * family Araliaceae
 * family Aralidiaceae
 * family Griseliniaceae
 * family Melanophyllaceae
 * family Pittosporaceae
 * family Torricelliaceae
 * order Aquifoliales
 * family Aquifoliaceae
 * family Helwingiaceae
 * family Phyllonomaceae
 * order Asterales
 * family Alseuosmiaceae
 * family Argophyllaceae
 * family Asteraceae
 * family Calyceraceae
 * family Campanulaceae [+ family Lobeliaceae]
 * family Carpodetaceae
 * family Donatiaceae
 * family Goodeniaceae
 * family Menyanthaceae
 * family Pentaphragmataceae
 * family Phellinaceae
 * family Rousseaceae
 * family Stylidiaceae
 * order Dipsacales
 * family Caprifoliaceae
 * family Diervillaceae
 * family Dipsacaceae
 * family Linnaeaceae
 * family Morinaceae
 * family Valerianaceae

Note: "+ ..." = optional seggregrate family, that may be split off from the preceding family.


 * Families of uncertain position
 * family Balanophoraceae
 * family Bonnetiaceae
 * family Cardiopteridaceae
 * family Ctenolophonaceae
 * family Cynomoriaceae
 * family Cytinaceae
 * family Dipentodontaceae
 * family Elatinaceae
 * family Geissolomataceae
 * family Hoplestigmataceae
 * family Kaliphoraceae
 * family Lepidobotryaceae
 * family Lissocarpaceae
 * family Lophopyxidaceae
 * family Medusandraceae
 * family Metteniusaceae
 * family Mitrastemonaceae
 * family Paracryphiaceae
 * family Pentaphylacaceae
 * family Peridiscaceae
 * family Plagiopteraceae
 * family Pottingeriaceae
 * family Sladeniaceae
 * family Strasburgeriaceae
 * family Tepuianthaceae