APG III Classification.pdf

This presentation has intended to offer a bird's eye view of the APG III classification of angiosperms.

1. PLANT SYSTEMATICS
APG III CLASSIFICATION

2. “BEHOLD HER, SINGLE IN THE FIELD”

3. A PRESENTATIONBY
DR. N. SANNIGRAHI, ASSOCIATEPROFESSOR
DEPARTMENT OFBOTANY,
NISTARINICOLLEGE, PURULIA,
D.B. ROAD, PURULIA(W.B) INDIA, 723101

4. PLANT CLASSIFICATION
Untildetailedgeneticevidencebecameavailable,theclassificationof
floweringplantswasbasedontheirmorphology(particularlythatofthe
flower)andtheirbiochemistry(whatkindsofchemicalcompoundthey
containedorproduced).Classificationsystemsweretypicallyproducedby
anindividualbotanistorbyasmallgroup.Theresultwasalargenumberof
suchsystems.Differentsystemsandtheirupdatestendedtobefavoredin
differentcountries;e.g.theEnglersystemincontinentalEurope;the
Bentham&HookersysteminBritain(particularlyinfluentialbecauseitwas
usedbyKew);theTakhtajansystemintheformerSovietUnionand
countrieswithinitssphereofinfluence;andtheCronquistsysteminthe
UnitedStates.TheAngiospermPhylogenyGroup,orAPG,referstoan
informalinternationalgroupofsystematicbotanistswhocametogetherto
trytoestablishaconsensusviewofthetaxonomyoffloweringplants
(angiosperms)thatwouldreflectnewknowledgeabouttheirrelationships
baseduponphylogeneticstudies.
TheTaxonomybeingsyntheticsciencehasbeendevelopedfromtimeto
timebytheadditionofvalueineveryrespect.

5. PLANT CLASSIFICATION
Theysetthemostrecentclassificationoffloweringplantsbasedon
phylogeneticdata-theAngiospermPhylogeneticGroupclassification.Its
fourversions(APGI,APGII,APGIII&APGIV)havebeenpublishedin
1998,2003,2009and2016respectively.Eachversionsupplantsthe
previousversion.Recognitionofmonophyleticgroupbasedonthe
informationreceivedfromvariousdisciplinessuchasgrossmorphology,
anatomy,embryology,palynology,karyology,phytochemistryandmore
stronglyonmoleculardatawithrespecttoDNAsequencesoftwo
chloroplastgenes(atpBandrbcL)andonenucleargene(nuclearribosomal
18sDNA).Themostrecentupdatedversion,APGIV(2016)recognized64
ordersand416families.Ofthese416families,259arerepresentedinIndia.
ThePlantclassificationisverydynamiconewiththepassageoftimeand
moreandmoredatainputfromthedifferentdomainsofknowledgehas
ultimatelymadethejourneymorefascinatingandcolorful.

6. PLANT CLASSIFICATION & APG
Intheearly1990s,thefirstlargeanalysesoffloweringplantsbasedon
DNAsequenceswerepublished.Thesehadbecomepossibleduetomajor
developmentsinDNAsequencingtechnologyandcomputingpowerinthe
late20thcentury.Floweringplantswerethefirstmajorgrouponwhich
largegroupsofscientistscollaboratedincomprehensiveanalysesofthis
type,collectingsequencesforthesamegenes,sothatthedatacouldbe
combined.In1993,alandmarkpaperwithananalysisof500flowering
plantswaspublishedbyMarkChase,andco-authors,theyearafterMark
movedfromtheUniversityofNorthCarolinatoKewalongwithBrigittia
Bremer,KareBremer,WalterS.Judd,DavidJMabberley,PeterFStevens.
Thispaperwasbasedonsequencesofoneofthemajorgenesinvolvedin
photosynthesis,andtheanalysisinvolvedthebotanistsworkingwiththe
computerprogrammersbecausetheprogramhadtoberewrittentoallow
themtoanalyzesuchalargedataset.TheOriginalAPGsystemofPlant
classificationbasedoncladisticsanalysisofDNAsequence.

7. PRINCIPLES OF APG SYSTEM
i.TheprinciplesoftheAPG’sapproachtoclassificationweresetoutinthe
firstpaperof1998andithasremainedunchangedinthesubsequent
revisionslikeAPGII,APGIII&APGIV.Thebasicprinciplesareas
followed:
ii.TheLinnaeansystemofordersandfamiliesshouldberetained.”The
familyiscentralinfloweringplantsystematics”.Anordinalclassification
offamiliesasproposedas“referencetoolofbroadutility”.Ordersare
treatedforteachingandstudyingfamilyrelationship.
iii.Groupsshouldbemonophyletici.e.allhavebeenderivedfromcommon
ancestor.Themainreasonwhyexistingsystemsarerejectedbecausethey
donothavetheproperty,theyarenotphylogenetic.
iv.Abroadapproachistakentodefiningthelimitsofthegroups.Large
ordersareconsideredmoreuseful.Familieswithsinglegenusandorders
havingsinglefamilyarekeptoutside.Itismadesokeepingmonophyly
inview.
v.Namedcladesateusedtofamiliesandorders.Theauthorspointoutthat
itisnotpossibleordesirabletonameallcladesinphylogenetictree;
namingsomecladesparticularlyordersandfamiliesmakeiteasyto
exchangeviewsandenhancediscussion.

8. APG III CLASSIFICATION
TheAPGIIIsystem(2009)ofplantclassificationisthethirdversionofits
kindmostlybasedonmoleculartaxonomyanditwaspublishedafter6and
½yearsofAPGIIplantclassification.MembersoftheLinnaeansocietyput
forthaformalphylogeneticclassificationofalllandplants,compatiblewith
theAPGIII.Thesystemconsistsof45ordersonthetaxonomicrankand14
newones.ThenewlyrecognizedordersareAmborellales,Nymphaeales,
Chloranthales,Petrosaviales,Trochodendrales,Buxales,Vitales,
Zygophyllales,Picramniales,Huerteales.Berberidopsidales,Escalloniales,
BrunialesandParacryphiales.
Thealternative“Bracketfamilies”wereleftoutinAPGIII,becauseits
inclusionintheprevioussystemhadbeenunpopular.
APGIIIrecognizes415families,42fewerthantheprevioussystem.$$of
the55bracketedfamilieswerediscontinuedand18otherfamilieswere
discontinued.

9. APG III CLASSIFICATION
Thedesignationofalternative"bracketedfamilies"wasabandonedinAPG
III,becauseitsinclusionintheprevioussystemhadbeenunpopular.APG
IIIrecognized415families,42fewerthanintheprevioussystem.Forty-
fourofthe55"bracketedfamilies"werediscontinued,and18otherfamilies
werediscontinuedaswell.Thediscontinuedbracketedfamilieswere:
Illiciaceae,Alliaceae,Agapanthaceae,Agavaceae,Aphyllanthaceae,
Hesperocallidaceae,Hyacinthaceae,Laxmanniaceae,Ruscaceae,
Themidaceae,Asphodelaceae,Hemerocallidaceae,Kingdoniaceae,
Fumariaceae,Pteridophyllaceae,Didymelaceae,Tetracentraceae,
Pterostemonaceae,Hypseocharitaceae,Francoaceae,Memecylaceae,
Lepuropetalaceae,Rhoipteleaceae,Medusagynaceae,Quiinaceae,
Malesherbiaceae,Turneraceae,Bretschneideraceae,Diegodendraceae,
Cochlospermaceae,Peganaceae,Tetradiclidaceae,Nyssaceae,
Ternstroemiaceae,Pellicieraceae,Aucubaceae,Donatiaceae,Lobeliaceae,
Desfontainiaceae,Diervillaceae,Dipsacaceae,Linnaeaceae,Morinaceae,
andValerianaceae.Theotherdiscontinuedfamilieswere:Limnocharitaceae,
Luzuriagaceae,Sparganiaceae,Ledocarpaceae,Heteropyxidaceae,
Psiloxylaceae,Oliniaceae,Rhynchocalycaceae,Parnassiaceae,Maesaceae,
Myrsinaceae,Theophrastaceae,Eremosynaceae,Polyosmaceae,
Tribelaceae,Aralidiaceae,Mackinlayaceae,andMelanophyllaceae

10. APG III CLASSIFICATION
20familieswereacceptedintheAPGIIIsystemwhichhadnotbeeninthe
previoussystem,andafewfamiliesweremovedtoadifferentposition.The
newlyrecognizedfamiliesare:Petermanniaceae,Schoepfiaceae,
Limeaceae,Lophiocarpaceae,Montiaceae,Talinaceae,Anacampserotaceae,
Centroplacaceae,Calophyllaceae,Guamatelaceae,Gerrardinaceae,
Dipentodontaceae,Capparidaceae,Cleomaceae, Cytinaceae,
Mitrastemonaceae,Metteniusaceae,Linderniaceae,Thomandersiaceae,and
Quintiniaceae.Thenumberoffamiliesnotplacedinanyorderwasreduced
from39to10.ApodanthaceaeandCynomoriaceaewereplacedamongthe
angiosperms,incertaesedis,thatis,notinanygroupwithinthe
angiosperms.Eightotherfamilieswereplacedincertaesedisinvarious
supra-ordinalgroupswithintheangiosperms.Theunplacedfamilieswere:
Apodanthaceae,Cynomoriaceae,Dasypogonaceae,Sabiaceae,Dilleniaceae,
Icacinaceae,Metteniusaceae,Oncothecaceae,Vahliaceae,and
Boraginaceae.ThecircumscriptionofthefamilyIcacinaceaeremains
especiallydoubtful.Apodytes,Emmotum,Cassinopsis,andafewother
generawereprovisionallyretainedwithinituntilfurtherstudiescan
determinewhethertheyproperlybelongthere.

11. APG III CLASSIFICATION
Threegenera(Gumillea,Nicobariodendron,andPetenaea)wereplaced
withintheangiospermsincertaesedis.GumilleahadbeenunplacedinAPG
II.NicobariodendronandPetenaeawerenewlyaddedtothelist.The
classificationisshownbelowintwoversions.Theshortversiongoestothe
levelofordersandoffamiliesunplacedinanorder.Thedetailedversion
showsallthefamilies.Ordersatthesamelevelintheclassificationare
arrangedalphabetically.Notethatordersmaynotcontainthesamefamilies
asinearlierversionsoftheAPGsystem(APGsystem,APGIIsystem).
Chase&Reveal(2009)gaveaformalclassificationoflandplantsmainly
consideringthealgaeinAPGIII.Tokeepharmonybetweenhierarchical
classificationandAPGsystem,alllandplantswereincludedunder
Equisetopsida.Angiospermaredividedinto15superorders.Alltotal56
ordersarelistedofwhich,twoChloranthalesareunplaced.Furtherseven
familiescouldnotbeaccommodated.

12. APG III CLASSIFICATION

13. MERITS OF THE CLASSIFICATION
i.Thesystemshowsmonophylyoriginingroups,
ii.Thesystemcoversthemultipledatafrommorphology,anatomy,
embryology,phytochemistry&moleculardata.
iii.Groupsnamesuptoordershavebeenassigned,
iv.Traditionaldivisionsoftheangiospermsintomonocotyledonsand
dicotyledonshasnotbeentakenintoaccount.Manymonocotsareputin
betweenprimitiveangiospermsandeudicots.Itcansolvetheproblemof
paraphylyamongmonocotsanddicotsintheearlystages.
v.Anumberofcladogramsintheclassificationshowsgeneralaffinities
betweenthevariousgroupsoforganisms.
vi.Primitivefamiliesareplacedatthebeginningoftheangiosperms.
vii.ThemergerofBudlejaceaeandMyotoraceaewithScrophulariaceaehave
beensupportedfrommorphologicalandmolecularevidencesgivenby
Bremeret.al(2001)andOlmsteadet.al(2001).
viii.Multigeneanalysisandmorphologicaldataarethebasisonwhich
WinteraceaeandCancellaceaearekeptunderthesameorder.

14. MERITS & DEMERITS OF THE CLASSIFICATION
FamilyAgavaceaeincludesgeneralikeHosta,CamassinaandChlorogalum
anditbecomesmorewide.ThisjustificationhasbeensupportedbyJudd
et.al(2002)andThorne.
MonophyleticconceptisreflectedinMalvaceaewherefamilieslike
Tiliaceae,SterculariaceaeandBombaceaeareincludedintheformer.This
inclusionissupportedbymolecularaswellasmorphologicaldata.
AsclepidaceaehasbeenmergedwithApocynaceae.Thisviewissupported
andstrengthenedbyJuddet.al(1994)frommolecularevidence.
TheconceptofbracketedfamiliesinearlierAPGhasbeenremovedinAPG
III.
DEMERITS
Thisclassificationisonlyapplicableuptofamilies.Thissystemisnot
suitableforidentificationofflorainthetruesense.
Thefateofsomeunplacedfamiliesandfewreplacedgeneraisstill
uncertain.
BotanicalnomenclatureCodehasnotbeenassignedtonewgroup.

15. ACKNOWLEDGMENT
Googleforimages,
Differentwebsitesforcontentandenrichment,
TextBookofPlantSystematics-ChittaranjanMohanty
PlantTaxonomybyO.P.Sharma,
Taxonomyofangiosperms-Nayek.
PlantTaxonomy-GurucharanSingh
AtextBookofBotany-Hait,Bhattacharyya&Ghosh
AdvancedPlantTaxonomy-A.K.Mondal.
Disclaimer:Thispresentationhasbeendevelopedtoenrichfreeopensource
ofthestudymaterialsforBiologystudentswithoutanyfinancialissues.

16. THANK YOU FOR YOUR JOURNEY