RECOGNITION OF PHRAGMITES AU STRAUS SUBSP. AMERICANUS (POACEAE: ARUNDINOIDEAE) IN NORTH AMERICA: EVIDENCE FROM MORPHOLOGICAL AND GENETIC ANALYSES

2004·3.9 MB·English

by  Kristin Saltonstall

RECOGNITIONOFPERAGMITESAUSTRAUSSUBSP.
AMERICANUS(POACEAE:ARUNDINOIDEAE)
INNORTHAMERICA:EVIDENCEFROMMORPHOLOGICAL
ANDGENETICANALYSES
KristinSaltonstall PaulM.PetersonandRobertJ.Soreng
HornPointLaboratory DepartmentofBotany
UniversityofMarylandCenter NationalMuseumofNaturalIHistory
forEnvironmentalScience SmithsonianInstitution
POBox775 Washington,DistrictofColumbia(DC)20013-7012,U.S.A.
Cambridge,Maryland21613,U.S.A. [email protected]
[email protected] [email protected]
ABSTRACT
AnewnativesubspeciesofPhragmitesaustralissubsp.americanusSaltonstall,P.M.Peterson&Soreng
ci3s.a0dn-e6sl.ci5rnimebaemgde.slToonhfge,P.nuaepupwstesrrauglbislspuembceyisehs5a.vc5ia-nn11gb.0ecamsdemupcaroloauntsge,dlelfaefrmosmmhaetashteh8s.i,0n-tl1ri3og.ud5luemcsemdI.aOl-onfnd.g7,GmualnmfdCblooyansgpt,osNlsooerwsetsrhmgAglmcuehmrleios--
roplastDNAhaplotypesofA-H,S,Z,AA.ThenewsubspeciesisclearlydistmguishedinaPCAanalysis
andwhenbivariateplotsofthemorphologicalfeaturesarecompared.Additionalworkisneededto
morphologicallydistinguishtheintroducedfromGulfCoastlineages.Phragmitesberlandieriis
lectotypified.Akeyanddistributionmapstothethreelineagesareincluded.
RESUMEN
SedescribeunanuevasubespecienativaPhragmitesaustralissubsp.americanusSaltonstall,RM.
Peterson&rSoreng.LanuevasubespeciepuedesepararsedelosImajesintroducidosenlaGulfCoast
d3.e0N-6o.r5tmemA,megrfiucmaadsesPu.paeursitorraelsisdpeo5r.5t-e1n1e,r0vmaimnalsoncga,dluceamsa,sldiegu8l.a0s-1d3e.51.m0-m1,.7ymmpo,rgtleunemrahsampfleortiioproessddeel
DNAplastidialA-H,S,Z,AA.Lanuevasubespeciequedaclaramentediferenciadaenunanalisisde
PCAycuandosecomparangraficosbivanantesdelascaracteristicasmorfologicas.Senecesitatrabajo
adicionalparadiferenciarmorfologicamenteloslinajesintroducidosdelaGulfCoast.Selectotipifica
Phragmitesberlandieri.Seincluyenunaclaveymapasdedistribuciondelostreslinajes,
PhragmitesAdans.isacosmopolitangenusfoundthroughouttheworldandis
currentlyplacedinthetribeArundmeaewithArundoL.,HakonechloaMakino
exHonda,andMoliniaSchrank,thelatterthreegeneraallintroducedinNorth
America(Sorengetal.2004;Zuloagaetal.2003).Phragmitesisanerectperen-
nialgrass,2-5mtall,thatcanformdensestands.Anumberofspecies,subspe-
cies,andvarietieshavehistoricallybeendescribedinthegenusPhragmitesand
todayfourspeciesarerecognized:P.australisiC^Y.)Trin.exSteud.,Pkarka(Retz.)
Trin.exSteud.,PmauritianusKunth,andP.japonicusSteud.Alltemperatesub-
speciesandvarietiesarenowincludedunderthedesignationPaustralis(Clay-
ton1968).UsingfivespecimenscollectedinTexasandMexico,Fournier(1877)
SIDA21(2):683-692.2004
684 BRIT.ORG/SIDA21(2)
distinguishedaNorthAmericanPhragmitcsCPberlfliic/icriE.Fourn.)fromthat
foundelsewhereintheworld.Basedonmeasurementsofglumesfrom28Euro-
peanspecimensandmanyNorthAmericanspecimens,Fernald(1932)sup-
portedthisdistinctionofaNorthAmericanvariety,Pcommunisvar.hcrlandicri
(E.Fourn.)Fernald.
RecentgeneticstudiesindicatethatthreegeneticlineagesofPhrci\!^mitc^
arefoundinNorthAmerica(Saltonstall2002,2003a,bJ. Alineageendemicto
NorthAmericaisfoundacrossmuchofCanadaandintheUnitedStates,from
NewEnglandandtheMid-AtlanticstatesacrosstothePacrficcoastandinto
thesouthwest(Fig.la).Regionalstructuringcanbefoundwithinthisnative
lineage,witheastcoast,midwestern,andwesternpopuhttionsshowingdiffer-
entchloroplastDNAhaplotypes(A-H,S,Z,AA,Saltonstall2003a).Another
hneageisfoundinthesouthernUnitedStatesfromFloridaacrosstotheGulf
ofCalifornia,andthislineageisalsofoundinCentralAmericaandinAsia(Fig.
lb).ItischaracterizedbychloroplasthaplotypeI(hereafterreferredtoasthe
GulfCoastlineage).Athirdlineage,chloroplasthaplotypeM,isFurAsianm
originandwaslikelyintroducedtoNorthAmericasinceEuropeancoloniza-
tion. Itis[oundacrossthecontinent,bothinareaswherePhragmilc^washis-
toricallypresentandalsoinplaces(suchasthesoutheastern US)where
PhragmitcsIsnotnativetotheflora(Fig.Ic;Saltonstall2002).Today,thisintro-
ducedlineageisthemostcommontypeofPhragmitcsmNorthAmericaand
canbefoundinavarietyofhabitatsincludingbothbrackishandfreshwater
marshes,mlandfens,alongthebanksofriversandlakes,andalongroadsides.
Withtherecognitionthatbothnativeandintroducedpopulationsof
Phragmitcsmaybepresent,manystateandregionalmanagementauthorities
arenowrevisingtheirPhragmitcsmanagementstrategicswithagoalofpre-
servingnativepopulationswhilecontrollingintroducedones.Thishasalso
encouragedNaturallieritageprogramstoconsiderlistingnativePhragmitcs
asarareorthreatenedplantinanumberofstates.However,theappropriatelevel
oftaxonomicclassificationofthedifferentlineageshasnotyetbeenclarified.
Anumberofqualitativecharactershavebeensuggestedfordistinguishing
thenativeandintroducedlineagesincludingculmcolor,culmtexture,andad-
herenceofleafsheathstoculms(Blossey2002).Whilethesecharactersappear
tobecorrelatedwithecologicalcharacteristics,theyareproblematicinthat
theyaresubjecttoobserverjudgmentandmayrequireobservationatdifferent
timesoltheyearAlthoughgenetictestingcanprovidedclinitiveinformation
astothelineageofapopulation,quantitati\'cmeasurementsofmorphological
featuresmayprovideameansofconfirmingorigininconjunctionwithquali-
tativecharacteristics.RobichaudandCatling(2003)performedsuchananaly-
sisusingPhragmitcsspecimetiscollectedinsouthernOntarioandfoundsig-
nificantdifferencesmthelengthofthelowerglumebetweenthenativeand
SALTONSTALLETAL.,RECOGNITIONOFPHRAGMITESAUSTRALISSUBSP.AMERICANUS 685
a. b.
c.
rK."r^
Fig.1.Distributionofa)Native,b)GulfCoast,andt)introducedlineagesof/'/jragm/fesflosfra/winNorthAmerica.Sources
ofdistributioninformationincludeCatlingetal.2004,COMREED1999,Saltonstall2002.
introducedpopulationlineages.However,thatstudywaslimitedbyitsgeo-
graphicscope.Thisstudyquantifiesdifferencesinsizeseenintheligules,lower
andupperglumes,andlemmasofnative,introduced,andGulfCoastpopula-
tionsofPhragmitesfromNorthAmerica.Weformallyrecognizethenativelin-
eagethatoccursintheUSAandCanadaasP.australissubsp.americanus
Saltonstall,P.M.Peterson&Soreng.
'AlthoughnotdocumentedacrosstheGulfCoastexceptforintheMississippiriverdelta(Saltonstall2002),
introducedPhragmitesmayalreadyhaveinvadedtheseregionsandcertainlyhasthepotentialtospreadinto
them.ThedistributionofintroducedP/irogm/resisnotknownsouthoftheU.S.borderandthusisnotincluded
inthisfigure.
686 BRIT.ORG/SIDA21(2)
METHODS
Thegeneticlineageofspecimenswasdeterminedpriortotakingmorphologi-
calmeasurements.DNAextractionsweredoneusingaCTABextractionproto-
col(Doyle&Dickson1987).Lineageswereidentifiedeitherbysequencingtwo
noncodingchloroplastgeneregions,trnr(UGU)-trnL(UAA)5'andrhcL-psal,
todeterminethechloroplastDNAhaplotype(Saltonstall2002)orusingan
RFLPdiagnosticassayontheabovementionedchloroplastregionsthatdistin-
guishesthethreeNorthAmericanPhragmiteslineages(Sahonstall2003c).
LigulesweremeasuredusingaNikonPZ500dissectingmicroscopefitted
witha0.1-10mmmicrometer.Allsampleswereobtainedfromlivepopulations
in1999-2003throughouttherangeofPhragmitesinNorthAmerica.Several
leafbladespersamplewereinitiallyobservedtoseeiftherewasvariationin
theligulelengths.Sincenowithin-plantorwithin-populationvariationwas
detectedonlyoneleafbladewasexaminedforthemajorityofspecimens.Ligule
lengthwascalculatedbymeasuringtheligule(boththemembraneanditshairy
margin)atthecenteroftheleafbladetothenearest0.05mm.
Measurementsoflowerandupperglumesandlemmasweretakenfroma
singleinflorescenceperclone.TenglumesandtenlemmasweremeasuredIrom
eachspecimen.Sampleswereobtainedfromlivepopulationsduring1999-2003
orfromherbariumspecimensandcoverthegeographicrangeofallPhragmites
lineagesinNorthAmerica.Measurementsweremadetothenearest0.5mm
usingarulerFromeachspecimen,tenspikeletsshowingvisiblerachillahairs
wereselectedfromthemiddlepartoftheinflorescence.Upperandlowerglume
andlemmalengthsweremeasuredfromthearticulatedbasetothetip.Acom-
pletedatasetofthemorphologicalcharactersusedinthisstudyisavailable
fromKSuponrequest.
DatawereanalyzedusingthePROCMIXEDproceduremSAS8.2.Tukey's
comparisonswereusedtodistinguishsignificantdifferencesbetweenpopula-
tiontypes.Sincethemajorityofsamplesmeasuredforligulelengthweredif-
ferentfromthosemeasuredforglumeandlemmalengths,thedatawereran-
domizedandtreatedasgroupsrepresentingvariationwithmeachofthethree
geneticlineages.Bivariatecomparisonswereplottedtoillustratethesediffer-
encesbetweenlineages.APrincipalComponentsAnalysis(PCA)wasperformed
usingPC-ORD(Version4,McCune&Mefford1999)usmgacorrelationmatrix
ofstandardizeddataforthevariables.
RESULTSANDDISCUSSION
Themorphologicalcharactersmeasuredinthisstudyclearlydistinguishna-
tivefromintroducedandGulfCoastPhragmiteslineages.Thismirrorsthedis-
tinctivenessseenatthegeneticlevelbetweenthelineages,whereallnativeNorth
Americanhaplotypessharedfiveuniquemutationsnotseeninanyotherhaplo-
types(Saltonstall2002).Nativespecimenshavelongerligules,glumes,andlem-
SALTONSTALLETAL.,RECOGNITIONOFPHRAGMITESAUSTRALISSUBSP.AMERICANUS 687
Table1.Meanvaluesandtheirsignificancelevelforiigule,glunneandlemmalengthsbyPhragmites
lineages:Native(N),Introduced(I),andGulfCoast(GC).
Structure PopulationType Samplesize Mean±SE(mm) SignificantDifference(p<0.01)
Ligule Native 28 1.26±0.04 l,GC
Introduced 20 0.69±0.03 N
GulfCoast 14 0.57±0.04 N
Lowerglume Native 28 4.6+0.1 l,GC
Introduced 17 3.4+0.1 N,GC
GulfCoast 15 3.9+0.1 N,l
Upperglume Native 28 7.3±0.2 l,GC
Introduced 17 5.8±0.2 N
GulfCoast 15 6.3+0.1 N
Lemma Native 28 11.1+0.2 l,GC
Non-Native 17 9.2+0.2 N
GulfCoast 15 10.1±0.2 N
masthanbothintroducedandGulfCoastspecimens(Table1;Ligule—F2,59=120.21;
Lowerglume-F2,57=37.59;Upperglume-F2,57=2L01;Lemma-F2,58=17.07;
p<0.0001forallcomparisons).Ofthefourcharactersmeasured,theliguleis
themostdefinitiveinseparatingthenativefromtheothertwolineages(Fig.
2a-c).Thelengthofthelowerglumeisalsoagoodwayofdistinguishingnative
fromintroducedspecimens,althoughsomeoverlapisseen(Fig.2d).
TheGulfCoastlineage,althoughsignificantlydifferentfromothersatsev-
eralmeasurements,isintermediatebetweentheothertwotypeswhencom-
paringthesefourcharacters(Table1,Fig.2a-d).Thusatthistime,itremains
difficulttodistinguishmorphologicallyanditappearsprematuretoconclude
thatthislineageisadifferentspecies(Jonesetal.1997).Itappearsmoresimilar
tointroducedthannativePhragmitesforallmorphologicalmeasurements,in
additiontobeinggeneticallymorecloselyrelatedtotheintroducedhaplotype
Mthanthenativehaplotypes(Saltonstall2002,2003a).Additionalcharacters
thatdistinguishthislineagemorphologicallyhaveyettobeidentified.Although
notverifiedquantitatively,theleafinternodedistanceoftheGulfCoastplants
appearstobeshorterthanboththeintroducedandnativelineages(Saltonstall
pers.obs.).ThesyntypeofP.herlandieri(J.l.BerlandierH46,US-82049exP)
wasincludedinourmorphologicalsurveyandfallswithintheGulfCoastlin-
eage.Fernald(1932)didnotindicateifheusedoneofthesyntypesdesignated
byFournier(1877)inhisstudyClearlyFernaldwasreferringtothenativelin-
eageinhisstudysincethelowerglumesrangefrom4-6mmlongandtheupper
glumesrangefrom6-8.5mmlong.Toavoidconfusioninthefuture,particu-
larlyifonechoosestousethenameP.herlandieritoincludetheGulfCoast
hneage,weformallylectotypifyP.herlandieriE.Fourn.,Bull.Soc.Bot.France
Fig,2a) b)
0.5 1 1.5
Ligule(mm)
c) d)
14 10
^^re10182 OoOoOr',AAA^^1A^^A^A. «SE ^,^^¥^^AA
_Ij 4^ «a o6ogu^fr""
3
4-
05 1 15 2 3 4 5
Ligule(mm) Lowerglume(mm)
Fig.2.BivariatecomparisonsofmorphologicaldataforNative{ ),Introduced()andGulfCoast(O)Phragmitesindividuals.
1
SALTONSTALLETAL.,RECOGNITIONOFPHRAGMITESAUSTRALISSUBSRAMERICANUS 689
Table2.Eigenvectorloadingsfortheprincipalcomponents(PC).Relativeeigenvalues,percentof
variance,andcumulativepercentofvariancearealsolisted.
PCI PC2 PCS PC4
Ligule -0.4030 0.8859 0.2293 -0.0143
Lowerglume -0.5285 0.0584 -0.7301 -0.4292
Upperglume -0.5489 0.2219 -0.0574 0.8038
Lemma -0.5069 0.4032 0.641 -0.4116
Eigenvalue 2.996 0.636 0.267 0.101
%ofvariance 74.904 15.905 6.676 2.515
Cumulative%ofvariance 74.904 90.809 97.485 100.000
24:178.1877.TypeU.S.A.Tf.xas:Laredo,1828,J.LBerlandierM'^6(lectotype:P;
isoi.ECTOTYPE,thelargespecimenonthesheetthatincludesaculmwithacom-
pleteinllorescence:LJS-82049exW!).
ThePCAconfirmedandenhancedtheabovementionedresultsfurther.The
firsttwoPCsaccountedfor90.8%ofthetotalvariationinthedata(Table2,Fig.
3).Thefirstaxisaloneaccountsfor74.9%ofthetotalvarianceandhasnegative
loadingsforthemajorityofNativespecimensandpositiveonesforintroduced
andGulfCoastspecimens.ThusmorenegativevaluesalongPCIindicatelarger
morphologicalstructures(Fig.2),asseeninthenativespecimens.
AnalysisofnuclearmicrosatelliteDNA indicatesthatthereislittleevi-
denceforhybridizationbetweenthenativeandintroducedlineagessincealle-
lesconsidereddiagnosticforeachofthetwolineagetypeswererarelyfoundin
thealternativelineage.Further,thisnuclearDNAdatasetstronglysupportsthe
geneticdifferentiationseeninthechloroplastDNAbetweenthenativeandin-
troducedlineages(Saltonstall200.3b).AlthoughPhragmiteshasbeensaidto
beself-mcompatible(Gustaffson&Simak1963),littleisknownaboutthemat-
ingsystemofthisgenusanditisnotknownifhybridsbetweenpopulation
typescanoccur.Themorphologicaldataclearlysupportseparationofthena-
tivelineagefromthemtroduced/GulfCoastlineages.Wehavedemonstrated
thatthenativelineagehasmorphologicalfeatures(longerligules,glumes,and
lemmas)anduniquegeneticmutationsthatdifferentiateitfromtheintroduced/
GulfCoastlineages.Wechosetorecognizethenativelineageformallyas
Pharagmitesaustralissubsp.amehcanus.Thefollowingkeyusingmorphologi-
calandgenotypefeaturesisgiventoseparatethesethreelineages.
KEYTOTHELINEAGESOFPHRAGMlThSAUSTRALISINNORTH AMERICA
1. mLimgulelsong1;.0l-1em.7mmasm8.l0o-n1g;3.l5owmemrgllounmg;esle3af.0s-h6i.e5atmhsmcaldonugc;ouupspweirthglaugmee;scu5l.m5-s1e1x.-0
posedinthewinter,smoothandshiny;rarelyoccursinamonoculture;chloroplast
DNAhaplotypesA-H,5,Z,AA(seeSaltonstall2002,2003a) P.australissubsp.americanus
(Nativelineage)
690 BRIT.ORG/SIDA21(2)
Fig.3.PrincipalcomponentsanalysisofmorphologicaldataforPhragmitesaustralis:Native( ),Introduced()and
GulfCoast(O)individuals.
1. Lmimgulelsong0;.4l-e0.m9mamsm7.l5o-n1g2;.0lomwemrglolnugm;elsea2f.s5h-e5.a0thmsmnotlocnag;duucpopuesrwgiltuhmaegse;4.c5u-l7m.s5
notexposedinthewinter,smoothandshinyorridgedandnotshiny;oftenoccurs
a2.saCumlomnsocsulmtouorteh;cahnldorsohpilnays;tsDoNutAhehranplCoatlyipfeorsniIao,rAMr.izona,NewMexico,Texasto
Florida,throughoutMexicoandCentralAmerica;chloroplastDNAhaplotypeI
Pausfra//svar.berlandieri(E.Fourn.)C.F.Reed(GulfCoastlineage)
2.Culmsridgedandnotshiny;southernCanadafromBritishColumbiatoQuebec
souththroughouttheContinentalUnitedStates;chloroplastDNAhaplotypeM
. ^_^_ Pou5fra//s(Introducedlineage)
Phragmites australissubsp.americanusSaltonstall,P.M.Peterson&Soreng,
Subsp.nov.Type:U.S.A.Montan.'\.FergusCo.:nearthemouthofDogCreek,12Sep1883,
FrankLamsonScnhncr378(iiOLOTYPi;:US-B24621!).
iAnfP'elnroargi)b?iuis(f3c.J0U-,6s.(5rtimlim(Calvo.n)gTinsn,.gexluSmtieusd.suvpaegnionaricbaudsuc5a.5c-1u1m.0ametmate,lloingguilsi,sl1e.0m-m1a.7timbmuslo8n.0g-i1s3..g5lummims
longis,recedit.
SALTONSTALLETAL.,RECOGNITIONOFPHRAGMITESAUSTRALISSUBSP.AMERICANUS 691
Plantsusuallydonotoccurasamonoculture.Culmsexposedinthewinter,
smoothandshiny,sometimespurplishatthenodesandinternodes.Leafsheaths
caducouswithage;ligules1.0-1.7mmmmlong.Spikeletlowerglumes3.0-6.5
mmlong,upperglumes5.5-11.0mmlong;lemmas8.0-13.5mmlong.
Distribution—(¥ig.la).Thissubspeciesisknowntooccurmsouthwestern
NorthwestTerritorieseastandsouthtoCalifornia,Arizona,NewMexico,and
easttonorthernTexas,Oklahoma,northernArkansas,WestVirginiaandNorth
Carolina,andnorthtoNewfoundlandandQuebec.
Specimensexamined(mcludedinthegeneticandmorphologicaldatasets):CANADA.BRITISH
COLUMBIA:OsoyorsLakeJ.Grants.n.(US-2432752).UNITEDSTATES.COLORADO:LaSalle.PA.
RMeyrdrbielrlg&25E1.1N.(WUSi-l9c0o8x14022)9.(UISO-W9A0.80F9a4y)e.ttIeNDCIo.A:NAB..FFiunlkto5n92Co(.U:SW-23of04R6o8c)h.esIteDrA,HCO.:C.SBt.eAanmt3h0o0n1y0,(EU.SD-.
1062053).KANSAS.PottawatomieCo.:J.B.S.Norton922(US-353717).MAINE:I^ikeAnagunticook,
HarfordJ.CParlin2022(US-908068).MICHIGAN.AlleganCo.:KalamazooRivernearDouglas,W.F.
Wright125CUS-430189).MINNESOTA:LakeMellissa,H.LBolley879(US-908078).MONTANA:banks
oftheMissouriRiver,F,LScribner378(US-153245).NORTHDAKOTA.HansonCo.:Leeds,J.Lunell
s2.0n.79(8U4S)-.89N8E85W3)J;ERNSEEBYR:ASNKeAw.DTuhrohmama.sWC.o.M:.SVaanndSHiiclklkssn.en.ar(UPSl-2u4m4m2e2r6),FoNrdE,WPAM.ERXyIdCbOe:rgB1r6e31mo(nUdSs-
RanchnearRoswell,j.D.Tinsky12(US-739106).NEVADA.NyeCo.:AmargosaDrainageBasin,j.C
Beatley9123(US-2876499).OKLAHOMA:EofWoodward,H.E.Runyan1030(1722877).OREGON:
KlammothCo.,KlammothLake,F.l.Applegate813(US-273602).SOUTHDAKOTA:Canning,D.
Gri//i(h.sJ0,5(US-9O8O84).UTAH:RabbitValley,L.F.Ward534(US453247).WASHINGTON.Okanogan
Co.:BanksoftheOkanoganRiver,A.D.E.Elmer519(US-352294).WYOMING.FremontCo.:Musk-
RatCreek,L.O.Gooding519(US-899997).
ACKNOWLEDGMENTS
WethankSusanPenningtonforhelpwiththeliteraturecitedandspecimen
citations,DanNicolsonandAlainTouwaideforcorrectingtheLatindiagnosis;
andBerndBlossey,J.K.Wipffandananonymousreviewerfortheircomments
onthemanuscript.ThisisContribution3787fromtheUniversityofMaryland
CenterforEnvironmentalSciences.
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