The APG II system (Angiosperm Phylogeny Group II system) of plant classification is the second, now obsolete, version of a modern, mostly

molecular A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bio ...

-based, system of plant taxonomy that was published in April 2003 by the Angiosperm Phylogeny Group.Angiosperm Phylogeny Group (2003)
An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II.
''

Botanical Journal of the Linnean Society The ''Botanical Journal of the Linnean Society'' is a scientific journal publishing original papers relating to the taxonomy of all plant groups and fungi, including anatomy, biosystematics, cytology, ecology, ethnobotany, electron microscopy ...

'' 141(4): 399-436. doi: 10.1046/j.1095-8339.2003.t01-1-00158.x It was a revision of the first APG system, published in 1998, and was superseded in 2009 by a further revision, the

APG III system The APG III system of flowering plant classification is the third version of a modern, mostly molecular-based, system of plant taxonomy being developed by the Angiosperm Phylogeny Group (APG). Published in 2009, it was superseded in 2016 by a fu ...

History

APG II was published as: *Angiosperm Phylogeny Group (2003). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II". ''

'' 141(4): 399-436. (Available online
Abstract

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doi: 10.1046/j.1095-8339.2003.t01-1-00158.x) Each of the APG systems represents the broad consensus of a number of systematic

botanist Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek wo ...

s, united in the APG, working at several institutions worldwide. The APG II system recognized 45

orders Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...

, five more than the APG system. The new orders were Austrobaileyales, Canellales, Gunnerales, Celastrales, and

Crossosomatales The Crossosomatales are an order, first recognized as such by APG II. They are flowering plants included within the Rosid eudicots. Description Species assigned to the Crossosomatales have in common flowers that are positioned solitarily, wit ...

, all of which were families unplaced as to order, although contained in supra-ordinal clades, in the APG system. APG II recognized 457 families, five fewer than the APG system. Thirty-nine of the APG II families were not placed in any order, but 36 of the 39 were placed in a supra-ordinal clade within the angiosperms. Fifty-five of the families came to be known as "bracketed families". They were optional segregates of families that could be circumscribed in a larger sense. The APG II system was influential and was adopted in whole or in part (sometimes with modifications) in a number of references. It was superseded 6½ years later by the

, published in October 2009.

Groups

Main groups in the system (all unranked

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English ter ...

s between the

ranks Rank is the relative position, value, worth, complexity, power, importance, authority, level, etc. of a person or object within a ranking, such as: Level or position in a hierarchical organization * Academic rank * Diplomatic rank * Hierarchy * H ...

class Class or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used differently ...

and

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...

): *angiosperms : *:

magnoliids Magnoliids (or Magnoliidae or Magnolianae) are a clade of flowering plants. With more than 10,000 species, including magnolias, nutmeg, bay laurel, cinnamon, avocado, black pepper, tulip tree and many others, it is the third-largest group of a ...

monocots Monocotyledons (), commonly referred to as monocots, ( Lilianae '' sensu'' Chase & Reveal) are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain only one embryonic leaf, or cotyledon. They constitute one of ...

*::

commelinids In plant taxonomy, commelinids (originally commelinoids) (plural, not capitalised) is a clade of flowering plants within the monocots, distinguished by having cell walls containing ferulic acid. The commelinids are the only clade that the APG I ...

eudicots The eudicots, Eudicotidae, or eudicotyledons are a clade of flowering plants mainly characterized by having two seed leaves upon germination. The term derives from Dicotyledons. Traditionally they were called tricolpates or non-magnoliid dicot ...

*:: core eudicots *::: rosids *:::: eurosids I *::::

eurosids II The rosids are members of a large clade ( monophyletic group) of flowering plants, containing about 70,000 species, more than a quarter of all angiosperms. The clade is divided into 16 to 20 orders, depending upon circumscription and classifica ...

*:::

asterids In the APG IV system (2016) for the classification of flowering plants, the name asterids denotes a clade (a monophyletic group). Asterids is the largest group of flowering plants, with more than 80,000 species, about a third of the total fl ...

*:::: euasterids I *:::: euasterids II Shown below is the classification in full detail, except for the fifteen genera and three families that were unplaced in APG II. The unplaced

taxa In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

were listed at the end of the appendix in a section entitled "Taxa of Uncertain Position". Under some of the clades are listed the families that were placed incertae sedis in that clade. Thirty-six families were so placed. This means that their relationship to other members of the clade is not known. *

paraphyletic In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In ...

grade

basal angiosperms The basal angiosperms are the flowering plants which diverged from the lineage leading to most flowering plants. In particular, the most basal angiosperms were called the ANITA grade, which is made up of ''Amborella'' (a single species of shrub f ...

*::: family Amborellaceae *::: family Chloranthaceae *::: family

Nymphaeaceae Nymphaeaceae () is a family of flowering plants, commonly called water lilies. They live as rhizomatous aquatic herbs in temperate and tropical climates around the world. The family contains nine genera with about 70 known species. Water ...

_family_Cabombaceae.html" ;"title="Cabombaceae.html" ;"title=" family Cabombaceae"> family Cabombaceae">Cabombaceae.html" ;"title=" family Cabombaceae"> family Cabombaceae*:: order Austrobaileyales *:: order Ceratophyllales *: clade

*::: order Canellales *::: order

Laurales The Laurales are an order of flowering plants. They are magnoliids, related to the Magnoliales. The order includes about 2500-2800 species from 85-90 genera, which comprise seven families of trees and shrubs. Most of the species are tropical ...

*::: order Magnoliales *::: order Piperales *: clade

*:::: family Petrosaviaceae *::: order Acorales *::: order

Alismatales The Alismatales (alismatids) are an order of flowering plants including about 4,500 species. Plants assigned to this order are mostly tropical or aquatic. Some grow in fresh water, some in marine habitats. Description The Alismatales compr ...

*::: order Asparagales *::: order Dioscoreales *::: order

Liliales Liliales is an order of monocotyledonous flowering plants in the Angiosperm Phylogeny Group and Angiosperm Phylogeny Web system, within the lilioid monocots. This order of necessity includes the family Liliaceae. The APG III system (2009) places ...

*::: order

Pandanales Pandanales, the pandans or screw-pines, is an order of flowering plants placed in the monocot clade in the Angiosperm Phylogeny Group and Angiosperm Phylogeny Web systems. Within the monocots Pandanales are grouped in the lilioid monocots where ...

*::clade

*::::: family

Dasypogonaceae Dasypogonaceae is a family of flowering plants, one that has not been commonly recognized by taxonomists; the plants it contains were usually included in the family Xanthorrhoeaceae. If valid, Dasypogonaceae includes four genera with 16 species ...

*:::: order

Arecales Arecales is an order of flowering plants. The order has been widely recognised only for the past few decades; until then, the accepted name for the order including these plants was Principes. Taxonomy The APG IV system of 2016 places Dasypogon ...

*:::: order Commelinales *:::: order Poales *:::: order

Zingiberales The Zingiberales are flowering plants forming one of four orders in the commelinids clade of monocots, together with its sister order, Commelinales. The order includes 68 genera and 2,600 species. Zingiberales are a unique though morphologi ...

*: clade

*:::: family Buxaceae _family_Didymelaceae.html" ;"title="Didymelaceae.html" ;"title=" family Didymelaceae"> family Didymelaceae">Didymelaceae.html" ;"title=" family Didymelaceae"> family Didymelaceae*:::: family Sabiaceae *:::: family Trochodendraceae [+ family Tetracentraceae] *::: order Proteales *::: order Ranunculales *:: clade core eudicots *::::: family Aextoxicaceae *::::: family Berberidopsidaceae *::::: family Dilleniaceae *:::: order Gunnerales *:::: order Caryophyllales *:::: order Santalales *:::: order Saxifragales *::: clade rosids *:::::: family Aphloiaceae *:::::: family Geissolomataceae *:::::: family

Ixerbaceae ''Ixerba brexioides'', the sole species in the genus ''Ixerba'', is a bushy tree with thick, narrow, serrated, dark green leaves and panicles of white flowers with a green heart. The fruit is a green capsule that splits open to reveal the black s ...

*:::::: family

Picramniaceae Picramniaceae is a small, mainly neotropical family of four genera '' Aenigmanu'', ''Alvaradoa'', ''Nothotalisia'' and ''Picramnia''. The family is the only member of the order Picramniales. Members of the family were formerly placed in the fami ...

*:::::: family Strasburgeriaceae *:::::: family Vitaceae *::::: order

*::::: order Geraniales *::::: order

Myrtales The Myrtales are an order of flowering plants placed as a sister to the eurosids II clade as of the publishing of the ''Eucalyptus grandis'' genome in June 2014. The APG III system of classification for angiosperms still places it within the e ...

*:::: clade eurosids I *::::::: family Zygophyllaceae _family_Krameriaceae.html" ;"title="Krameriaceae.html" ;"title=" family Krameriaceae"> family Krameriaceae">Krameriaceae.html" ;"title=" family Krameriaceae"> family Krameriaceae*::::::: family Huaceae *:::::: order Celastrales *:::::: order Cucurbitales *:::::: order Fabales *:::::: order Fagales *:::::: order Malpighiales *:::::: order Oxalidales *:::::: order Rosales *:::: clade

*::::::: family Tapisciaceae *:::::: order Brassicales *:::::: order Malvales *:::::: order Sapindales *::: clade

*::::: order Cornales *::::: order Ericales *:::: clade euasterids I *::::::: family

Boraginaceae Boraginaceae, the borage or forget-me-not family, includes about 2,000 species of shrubs, trees and herbs in 146, to 156 genera with a worldwide distribution. The APG IV system from 2016 classifies the Boraginaceae as single family of the ...

*::::::: family Icacinaceae *::::::: family Oncothecaceae *::::::: family Vahliaceae *:::::: order Garryales *:::::: order Gentianales *:::::: order Lamiales *:::::: order Solanales *:::: clade euasterids II *::::::: family Bruniaceae *::::::: family

Columelliaceae Columelliaceae is a family of trees and shrubs native to the Andes of South America. In the APG II taxonomy it is placed in the order Lamiales, but a 2008 study suggested that the family is sister to the Bruniaceae, and the Angiosperm Phylogen ...

_family_Desfontainiaceae.html" ;"title="Desfontainiaceae.html" ;"title=" family Desfontainiaceae"> family Desfontainiaceae">Desfontainiaceae.html" ;"title=" family Desfontainiaceae"> family Desfontainiaceae*::::::: family Eremosynaceae *::::::: family Escalloniaceae *::::::: family Paracryphiaceae *::::::: family Polyosmaceae *::::::: family Sphenostemonaceae *::::::: family Tribelaceae *:::::: order Apiales *:::::: order Aquifoliales *:::::: order Asterales *:::::: order Dipsacales Note: "+ ..." = optionally separate family, that may be split off from the preceding family.

References

{{List of systems of plant taxonomy APG 02 * 2003 in science 2003 introductions Angiosperm Phylogeny Group