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 bioche ...

-based, system of plant taxonomy that was published in April 2003 by the

Angiosperm Phylogeny Group The Angiosperm Phylogeny Group (APG) is an informal international group of systematic botanists who collaborate to establish a consensus on the taxonomy of flowering plants (angiosperms) that reflects new knowledge about plant relationships disco ...

.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, mo ...

'' 141(4): 399-436. doi: 10.1046/j.1095-8339.2003.t01-1-00158.x It was a revision of the first

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 AP ...

, published in 1998, and was superseded in 2009 by a further revision, the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 Published in 2009, it was superseded in 2016 by a fur ...

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

Full text (HTML)

Full text (PDF)
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 d ...

, five more than the APG system. The new orders were

Austrobaileyales Austrobaileyales is an order of flowering plants consisting of about 100 species of woody plants growing as trees, shrubs and lianas. The best-known species is ''Illicium verum'', commonly known as star anise. The order belongs to the group of ...

Canellales Canellales is the botanical name for an order of flowering plants, one of the four orders of the magnoliids. It is recognized by the most recent classification of flowering plants, the APG IV system. It is defined to contain two families: Canel ...

Gunnerales The Gunnerales are an order of flowering plants. In the APG III system (2009) and APG IV system (2016) it contains two genera: '' Gunnera'' (in family Gunneraceae) and ''Myrothamnus'' (in family Myrothamnaceae). In the Cronquist system (1981), ...

Celastrales The Celastrales are an order of flowering plants found throughout the tropics and subtropics, with only a few species extending far into the temperate regions. The 1200"Lepidobotryaceae", "Parnassiaceae", and "Celastraceae" In: Klaus Kubitzki ( ...

, 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, with ...

, all of which were families unplaced as to order, although contained in supra-ordinal clades, in the APG system. APG II recognized 457

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideal ...

, 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 geometry, the circumscribed circle or circumcircle of a polygon is a circle that passes through all the vertices of the polygon. The center of this circle is called the circumcenter and its radius is called the circumradius. Not every polyg ...

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 term, ...

s between the ranks of

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 differentl ...

and order): *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 t ...

*::

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 dico ...

*::

core 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 dicots ...

*:::

rosids 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 classificatio ...

*::::

eurosids I 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 classificatio ...

*::::

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 classific ...

*:::

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 flowe ...

*::::

euasterids I 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 floweri ...

*::::

euasterids II 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 floweri ...

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 ' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...

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 (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

grade Grade most commonly refers to: * Grade (education), a measurement of a student's performance * Grade, the number of the year a student has reached in a given educational stage * Grade (slope), the steepness of a slope Grade or grading may also ref ...

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 ''Amborella'' is a monotypic genus of understory shrubs or small trees endemic to the main island, Grande Terre, of New Caledonia in the southwest Pacific Ocean. The genus is the only member of the family Amborellaceae and the order Amborellale ...

*::: family

Chloranthaceae Chloranthaceae is a family of flowering plants (angiosperms), the only family in the order Chloranthales. It is not closely related to any other family of flowering plants, and is among the early-diverging lineages in the angiosperms. They are ...

*::: 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 li ...

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

*:: order Ceratophyllales *: clade

*::: 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 an ...

*::: order

Magnoliales The Magnoliales are an order of flowering plants. Classification The Magnoliales include six families: * Annonaceae (custard apple family, over 2000 species of trees, shrubs, and lianas; mostly tropical but some temperate) * Degeneriaceae (two ...

*::: order

Piperales Piperales is an order of flowering plants (4,170 recognized species). It necessarily includes the family Piperaceae but other taxa have been included or disincluded variously over time. Well-known plants which may be included in this order inclu ...

*: clade

*:::: family

Petrosaviaceae Petrosaviaceae is a family of flowering plants belonging to a monotypic order, Petrosaviales. Petrosaviales are monocots, and are grouped within the lilioid monocots. Petrosaviales are a very small order (one family, two genera and four species ...

*::: order

Acorales ''Acorus'' is a genus of monocot flowering plants. This genus was once placed within the family Araceae (aroids), but more recent classifications place it in its own family Acoraceae and order Acorales, of which it is the sole genus of the oldes ...

*::: 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 compri ...

*::: order

Asparagales Asparagales (asparagoid lilies) is an order (biology), order of plants in modern classification systems such as the Angiosperm Phylogeny Group (APG) and the Angiosperm Phylogeny Web. The order takes its name from the type (biology), type family ...

*::: order

Dioscoreales The Dioscoreales are an order of monocotyledonous flowering plants in modern classification systems, such as the Angiosperm Phylogeny Group and the Angiosperm Phylogeny Web. Within the monocots Dioscoreales are grouped in the lilioid monocots ...

*::: order Liliales *::: 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 wh ...

*::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 Dasypogo ...

*:::: order

Commelinales Commelinales is an order of flowering plants. It comprises five families: Commelinaceae, Haemodoraceae, Hanguanaceae, Philydraceae, and Pontederiaceae. All the families combined contain over 885 species in about 70 genera; the majority of sp ...

*:::: order

Poales The Poales are a large order of flowering plants in the monocotyledons, and includes families of plants such as the grasses, bromeliads, and sedges. Sixteen plant families are currently recognized by botanists to be part of Poales. Descriptio ...

*:::: 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 morphological ...

*: clade

*:::: family

Buxaceae The Buxaceae are a small family of six genera and about 123 known species of flowering plants. They are shrubs and small trees, with a cosmopolitan distribution. A seventh genus, sometimes accepted in the past (''Notobuxus''), has been shown ...

_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

*::::: family Aextoxicaceae *::::: family Berberidopsidaceae *::::: family

Dilleniaceae Dilleniaceae is a family of flowering plants with 11 genera and about 430 known species. Such a family has been universally recognized by taxonomists. It is known to gardeners for the genus ''Hibbertia'', which contains many commercially valuabl ...

*:::: order

Caryophyllales Caryophyllales ( ) is a diverse and heterogeneous order of flowering plants that includes the cacti, carnations, amaranths, ice plants, beets, and many carnivorous plants. Many members are succulent, having fleshy stems or leaves. The betalai ...

*:::: order

Santalales The Santalales are an order of flowering plants with a cosmopolitan distribution, but heavily concentrated in tropical and subtropical regions. It derives its name from its type genus ''Santalum'' (sandalwood). Mistletoe is the common name for a ...

*:::: order

Saxifragales The Saxifragales (saxifrages) are an order of flowering plants (Angiosperms). They are an extremely diverse group of plants which include trees, shrubs, perennial herbs, succulent and aquatic plants. The degree of diversity in terms of vege ...

*::: clade

*:::::: family

Aphloiaceae ''Aphloia'' is a genus of flowering plants that contains a single species, ''Aphloia theiformis'', the sole species of the monogeneric family Aphloiaceae. It is a species of evergreen shrubs or small trees occurring in East Africa, Madagasca ...

*:::::: family

Geissolomataceae ''Geissoloma'' is a genus of flowering plants in the monotypic family Geissolomataceae, native to the Cape Province of South Africa. The plants are xerophytic evergreen shrubs and are known to accumulate aluminum Aluminium (aluminum in A ...

*:::::: family Ixerbaceae *:::::: 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 fa ...

*:::::: family

Strasburgeriaceae Strasburgeriaceae is a small family of flowering plants in the order Crossosomatales, only found in New Zealand and New Caledonia. It contains two genera, '' Strasburgeria'' and ''Ixerba''. Both genera have simple, evergreen, alternated leaves, o ...

*:::::: family

Vitaceae The Vitaceae are a family of flowering plants, with 14 genera and around 910 known species, including common plants such as grapevines (''Vitis'' spp.) and Virginia creeper (''Parthenocissus quinquefolia''). The family name is derived from the ge ...

*::::: order

Geraniales Geraniales is a small order of flowering plants, included within the rosid subclade of eudicots. The largest family in the order is Geraniaceae with over 800 species. In addition, the order includes the smaller Francoaceae with about 40 speci ...

*::::: order Myrtales *:::: clade

*::::::: family

Zygophyllaceae Zygophyllaceae is a family of flowering plants that contains the bean-caper and caltrop. The family includes around 285 species in 22 genera. Plants in the family Zygophyllaceae may be trees, shrubs, or herbs. They are often found in dry habit ...

_family_Krameriaceae.html" ;"title="Krameriaceae.html" ;"title=" family Krameriaceae"> family Krameriaceae">Krameriaceae.html" ;"title=" family Krameriaceae"> family Krameriaceae*::::::: family Huaceae *:::::: order

*:::::: order

Cucurbitales The Cucurbitales are an order of flowering plants, included in the rosid group of dicotyledons. This order mostly belongs to tropical areas, with limited presence in subtropical and temperate regions. The order includes shrubs and trees, togethe ...

*:::::: order

Fabales The Fabales are an order (biology), order of flowering plants included in the Rosids, rosid group of the eudicots in the APG II system, Angiosperm Phylogeny Group II classification system. In the APG II circumscription, this order includes the f ...

*:::::: order

Fagales The Fagales are an order of flowering plants, including some of the best-known trees. The order name is derived from genus ''Fagus'', beeches. They belong among the rosid group of dicotyledons. The families and genera currently included are a ...

*:::::: order

Malpighiales The Malpighiales comprise one of the largest orders of flowering plants, containing about 36 families and more than species, about 7.8% of the eudicots. The order is very diverse, containing plants as different as the willow, violet, poinsett ...

*:::::: order

Oxalidales Oxalidales is an order of flowering plants, included within the rosid subgroup of eudicots. Compound leaves are common in Oxalidales and the majority of the species in this order have five or six sepals and petals. The following families are typic ...

*:::::: order

Rosales Rosales () is an order of flowering plants. Peter F. Stevens (2001 onwards). "Rosales". At: Trees At: Angiosperm Phylogeny Website. At: Missouri Botanical Garden Website. (see ''External links'' below) It is sister to a clade consisting of Faga ...

*:::: clade

*::::::: family

Tapisciaceae Tapisciaceae is a family of flowering plants. Until recently it had been abandoned by taxonomists, and it was not recognised in the APG II system of 2003. In the APG III system, however, it has been reinstated to encompass the two genera '' Tapis ...

*:::::: order

Brassicales The Brassicales (or Cruciales) are an order (biology), order of flowering plants, belonging to the eurosids II group of dicotyledons under the APG II system. One character common to many members of the order is the production of glucosinolate (mu ...

*:::::: order

Malvales The Malvales are an order of flowering plants. As circumscribed by APG II-system, the order includes about 6000 species within 9 families. The order is placed in the eurosids II, which are part of the eudicots. The plants are mostly shrubs and ...

*:::::: order

Sapindales Sapindales is an order of flowering plants. Well-known members of Sapindales include citrus; maples, horse-chestnuts, lychees and rambutans; mangos and cashews; frankincense and myrrh; mahogany and neem. The APG III system of 2009 includes it ...

*::: clade

*::::: order

Cornales The Cornales are an order of flowering plants, early diverging among the asterids, containing about 600 species. Plants within the Cornales usually have four-parted flowers, drupaceous fruits, and inferior to half-inferior gynoecia topped with ...

*::::: order

Ericales The Ericales are a large and diverse order of dicotyledons. Species in this order have considerable commercial importance including for Camellia sinensis, tea, persimmon, blueberry, kiwifruit, Brazil nuts, Argania, argan, and azalea. The order i ...

*:::: clade

*::::::: 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 order ...

*::::::: family

Icacinaceae The Icacinaceae, also called the white pear family, are a family of flowering plants,"Icacinaceae" At: Angiosperm Phylogeny Website At: Missouri Botanical Garden Website (see ''External links'' below). consisting of trees, shrubs, and lianas, pri ...

*::::::: family Oncothecaceae *::::::: family Vahliaceae *:::::: order

Garryales The Garryales are a small order of dicotyledons, including only two families and three genera. Description Garryales are woody plants that are either hairless or have very fine hairs. Members of the family Garryaceae are evergreen, whereas thos ...

*:::::: order

Gentianales Gentianales is an order of flowering plants, included within the asterid clade of eudicots. It comprises more than 20,000 species in about 1,200 genera in 5 families. More than 80% of the species in this order belong to the family Rubiaceae. Man ...

*:::::: order

Lamiales The order Lamiales (also known as the mint order) are an order in the asterid group of dicotyledonous flowering plants. It includes about 23,810 species, 1,059 genera, and is divided into about 25 families. These families include Acanthaceae, Bi ...

*:::::: order

Solanales The Solanales are an order of flowering plants, included in the asterid group of dicotyledons. Some older sources used the name Polemoniales for this order. Taxonomy Under the older Cronquist system, the latter three families were placed elsewh ...

*:::: clade

*::::::: family

Bruniaceae Bruniaceae is a family of shrubs native to the cape region of South Africa. They are mostly restricted to the Cape Province, but a small number of species occur in KwaZulu-Natal. Description Species belonging to the Bruniaceae are heath-like s ...

*::::::: 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 The Aquifoliales are an order of flowering plants, including the Aquifoliaceae (holly) family, and also the Helwingiaceae (2-5 species of temperate Asian shrubs) and the Phyllonomaceae (4 species of Central American trees and shrubs). In 2001, t ...

*:::::: order

Asterales Asterales () is an order of dicotyledonous flowering plants that includes the large family Asteraceae (or Compositae) known for composite flowers made of florets, and ten families related to the Asteraceae. While asterids in general are charact ...

*:::::: order

Dipsacales The Dipsacales are an order of flowering plants, included within the asterid group of dicotyledons. In the APG III system of 2009, the order includes only two families, Adoxaceae and a broadly defined Caprifoliaceae. Some well-known members of th ...

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