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APG system, published in 1998, and was superseded in 2009 by a further revision, the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 Published in 2009, it was superseded in 2016 by a fu ...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". ''
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. (Available online
AbstractFull 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 ...
, 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
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 ...
, 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 ...
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 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
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 ...
*::: 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
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 ...
*:::: 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
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 ...
*::::: 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
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 ...
*:::: 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
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 ...
*::::: 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
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 ...
*::::::: family
Tapisciaceae
*:::::: order
Brassicales
*:::::: order
Malvales
*:::::: order
Sapindales
*::: clade
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 ...
*::::: 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