Angiosperm Phylogeny Group (APG) system
As molecular data from different plants become available and as powerful tools of data handling developed, it became possible to apply cladistic concepts to plant classification. This has lead to development of APG classifications by collaborative efforts of an international group of dedicated systematic botanists of ‘Angiosperm Phylogeny Group’,who published different APG classifications (APGI,APGII,APG III and APGIV) from time to time the most recent one being APGIV. APG III was published in 2009 in the Botanical Journal of the Linnean Society. In APG classifications families are grouped into putative monophyletic orders under a small number of informal monophyletic higher groups: magnoliids, monocots, commelinoids, eudicots, core eudicots, rosids, eurosids I, eurosids II, asterids, euasterids I and euasterids II. Under these informal groups there are also listed a number of families without assignment to order.
The Angiosperm Phylogeny Group, or APG, refers to an informal international group of systematic botanists who came together to try to establish a consensus view of the taxonomy of flowering plants (angiosperms) that would reflect new knowledge about their relationships based upon phylogenetic studies.
APG III system
Traditionally, the flowering plants were divided into two groups, dicotyledon (plural dicotyledons) and monocotyledon (plural monocotyledons). Recent studies, as by the APG, show that the monocots form a monophyletic group (clade) but that the dicots do not (they are paraphyletic). Nevertheless, the majority of dicot species do form a monophyletic group, called the eudicots or tricolpates. Of the remaining dicot species, most belong to a third major clade known as the Magnoliidae, containing about 9,000 species. The rest include a paraphyletic grouping of primitive species known collectively as the basal angiosperms, plus the families Ceratophyllaceae and Chloranthaceae. APG III system contains 415 families and 59 orders; 10 families are not placed in an order and two families (Apodanthaceae and Cynomoriaceae) are left entirely outside the classification.
The classification is shown below up to the level of orders and of families unplaced in an order. Orders at the same level in the classification are arranged alphabetically. Further detail on relationships can be seen in the phylogenetic tree below.
APGIII Classification
Bhairab Ganguly College|RKG April 2020 | 1 ∙ clade angiosperms
§ order Amborellales
§ order Nymphaeales
§ order Austrobaileyales
§ order Chloranthales
o clade magnoliids
§ order Canellales
§ order Laurales
§ order Magnoliales
§ order Piperales
o clade monocots
§ order Acorales
§ order Alismatales
§ order Asparagales
§ order Dioscoreales
§ order Liliales
§ order Pandanales
§ order Petrosaviales
§ clade commelinids
∙ family Dasypogonaceae -- unplaced in an order
§ order Arecales
§ order Commelinales
§ order Poales
§ order Zingiberales
o probable sister of eudicots
§ order Ceratophyllales
o clade eudicots
Bhairab Ganguly College|RKG April 2020 | 2 ∙ family Sabiaceae -- unplaced in an order
§ order Buxales
§ order Proteales
§ order Ranunculales
§ order Trochodendrales
§ clade core eudicots
∙ family Dilleniaceae -- unplaced in an order
§ order Gunnerales
§ order Saxifragales
∙ clade rosids
§ order Vitales
o clade fabids (eurosids I)
§ order Celastrales
§ order Cucurbitales
§ order Fabales
§ order Fagales
§ order Malpighiales
§ order Oxalidales
§ order Rosales
§ order Zygophyllales
o clade malvids (eurosids II)
§ order Brassicales
§ order Crossosomatales
§ order Geraniales
§ order Huerteales
§ order Malvales
§ order Myrtales
§ order Picramniales
Bhairab Ganguly College|RKG April 2020 | 3 § order Sapindales
§ (back to core eudicots)
§ order Berberidopsidales
§ order Caryophyllales
§ order Santalales
o clade asrerids
∙ order Cornales
∙ order Ericales
o clade lamiids (euasterids I)
∙ family Boraginaceae -- unplaced in an order
∙ family Vahliaceae -- unplaced in an order
∙ family Icacinaceae -- unplaced in an order
∙ family Metteniusaceae -- unplaced in an order
∙ family Oncothecaceae -- unplaced in an order
§ order Garryales
§ order Gentianales
§ order Lamiales
§ order Solanales
o clade campanulids (euasterids II)
§ order Apiales
§ order Aquifoliales
§ order Asterales
§ order Bruniales
§ order Dipsacales
§ order Escalloniales
§ order Paracryphiales
References
Bhairab Ganguly College|RKG April 2020 | 4 ∙ Angiosperm Phylogeny Group (2009), "An update of the Angiosperm Phylogeny Group classification for the ∙ orders and families of flowering plants: APG III", Botanical Journal of the Linnean Society 161 (2): 105– ∙ 121. ∙ As easy as APG III - Scientists revise the system of classifying flowering plants, The Linnean Society of ∙ London, 2009-10-08. ∙ Chase, Mark W. & Reveal, James L. (2009), "A phylogenetic classification of the land plants to accompany ∙ APG III", Botanical Journal of the Linnean Society 161 (2): 122–127. ∙ Chase, M.W.; Reveal, J.L. & Fay, M.F. (2009), "A subfamilial classification for the expanded asparagalean ∙ families Amaryllidaceae, Asparagaceae and Xanthorrhoeaceae", Botanical Journal of the Linnean Society ∙ 161 (2): 132–136.
Bhairab Ganguly College|RKG April 2020 | 5 Interrelationships of the APG III orders and some families. Newly-recognized-for-APG orders are denoted (†). Some eudicot families not yet classified to order are not shown. Bhairab Ganguly College|RKG April 2020 | 6