ENDEMIC VASCULAR PLANTS OF THE INTERIOR HIGHLANDS, U.S.A

2005·4.7 MB·English

by  Douglas Zollner

ENDEMICVASCULARPLANTSOFTHEINTERIOR
HIGHLANDS,U.S.A.
DouglasZollner MichaelH.MacRoberts
TheNatureConservancy BogResearch
601NorthUniversity 740Columbia
LittleRock.Arl<ansas72205,USA. Shreveport,Louisiana71104,U.S.A.
Barbara R.MacRoberts DouglasLadd
Herbarium,MuseumofLifeSciences TheNatureConservancy
LouisianaStateUniv-Shreveport 2800S.Brentwood
Shreveport,Louisiana71115,U.S.A. St.Louis,Missouri63144,U.S.A.
ABSTRACT
Weevaluatethe36cndemievascularplatitsoftheInteriorHighlancisolArkansas,Illinois,Kansas,
Missouri,andOklahoma.Mostoftheendemicfloraoftheregionareherbaceousperennials,although
nearlyaquarteroftheendemicplanttaxaareannuals.AnanalysisofthecommunityaiIiliationsof
theregion'sendemic1lorarevealsthatmostendemictaxaareassociatedwithgladehabitatsmain-
tainedb)'edaphicconditionsandfire.Riparianhabitatsandlire-maintained]iine-oakwoodlands
areotherliabitatassociationswithsignilicantendemicIlora.TheOuachitaMountainsregionolthe
InteriorHighlandscontainsadisproportionaterepresentationoltheendemictaxarelativetoitsarea,
althoughthereisalsoasmallercohortofendemicsrestrictedtotheOzarkportionoltheInterior
Highlands.
Khywords:InteriorIlighlands.endemicIlora,biogeography,biodiversit)',Ozarks,Ouachitas,Arkan-
sas,Illinois,Kansas,Missouri,Oklahoma
RESUMEN
Hemosevaluadolas36plantasvascularesendemicasdelasInteriorIlighlandsdeArkansas,Illinois,
Kansas,Missouri,yOklahoma.Lamayorpartedelafloraendemicadelaregionsonherbaceasperennes,
auncjuccasilacuartapartedclasplantasendemicassontaxaanuales.Unanalisisdelasprelerencias
delascomunidadesdelailoraendemicadelaregi6nrevelaquelamayoriadelosta.xaendcmicosestan
asociadosconhabitatspantanososquesemantienenporlascondicionesedaiicasyeltuego,Los
habitatsripariosybosc|uesde|iino-roblemantenidosporelfuegosonlosotroshabitatsconelementos
defloraendemicasignificativos.LaregiondelasMontanasdeOuachitadelInteriorHighlands
contieneunarepresentaciondesproporcionadadetaxaendemicosdeestaarea,aunquehaytambien
unapequenacohortedeendemismosrestringidosalapartedeOzarkdelasInteriorHighlands.
INTRODUCTION
Listsofendemictaxaarevaluabletoolsfordefiningtheuniquenessandcon-
servationsignificanceofbiogeographicregions(Takhtajan1986)andinestab-
lishingbiodiversity"hotspots"forconservationpriorities(Diamondetal.1997;
Rickettsetal.1999;Myersetal,2000;Stemetal.2000;Estill&Cruzan2001).
Fewbiogeographicregions,however,havedetailedendemicvascularplantlists.
SIDA21(3):1781-179L2005
1782 BRIT.ORG/SIDA21(3)
Forexample,onlyrecentlyhaveendemicplantlistsbeendevelopedfortheAt-
lanticandGulfCoastalPlainandtheWestGulfCoastalPlain(Sorrie&Weakley
2001;MacRobertsetal.2002).
TheInteriorHighlandsphysiographicregionhasbeenrelativelywell-de-
scribedphysicallyandbiotically(Fenneman1938;Foti1974;Nelson1985;Thorn
&Wilson1980;Bryantetal.1993;NighandSchroeder2002;Skeenetal.1993;
Foti&Bukenhofer1998;Delcourt&Delcourt2000).Theregionhasanexten-
sivebotanicalliterature,includingIlorasandatlases(Steyermark1963;Peck&
Peck1988;Smith1988,1994;Taylor«&rTaylor1989;Pecketal.2001;Yatskievych
1999),butithasnocomprehensivelistolendemicvascularplants,andmost
botanicalinformationiscompartmentalizedbystate.
AsshowninFigure1,theInteriorHighlandsarecomprisedoftheOzarks,
Ouachitas,andArkansasValleysections,andincludesignificantportionsolAr-
kansas,Missouri,andOklahoma,alongwithminorareasofIllinoisandKansas.
Thisregionhaslongbeenrecognizedasageologically,physiographically,eco-
logically,andculturallydistinctregionofNorthAmerica,andconstitutesthe
onlyhighlandsinmidcontinentalNorthAmerica.TheOuachitaMountainsare
east-westtrendingfold-beltrangesofintenselydeformedsandstone,shale,and
chert(Miser1929).Thenorthernrangesarelonghogbackridgesotsandstone
separatedbybroadvalleys.Thesouthernrangesaresharpridgesofnovaculite
separatedbynarrow,stonyvalleys(Croncis1930).TheArkansasValleyisabroad
alluvialplainwithisolatedmountainsthatgenerallyseparatestheOuachita
MountainsfromtheOzarkPlateau.Structurally,theOzarkPlateauisadomethat
hasbeenslowlyupliftedanderoded,resultinginhighlevelsoftopographic,geo-
logic,edaphic,andhydrologicdiversity.Bedrockgeologyincludesexposuresof
PrecambrianigneousrockssurroundedbyalternatingzonesofPaleozoicsand-
stoneandcarbonatesedimentaryrocks(NighandSchroeder2002).Boththe
OuachitaandOzarkportionsofthehighlandsarccharacterizedbyrugged,dis-
secteduplandswithabundantexposedrocksandhighlyvariablesoildepths.
ThispaperenumeratestheendemicvascularplantsoftheInteriorHigh-
lands,alongwithmtormationabouteachspecies,itsplantcommunityaffilia-
tionsandtheecologicalprocessesthatmaintainthesespecies.Thesedatacan
beusedtofocusactivitiesonthehabitats,ecologicalsystems,andecological
processregimesingreatestneedofconservationaction.Gladeisusedhereto
mean,openherbaceous-dominatedhabitatswithsparsetreeandshrubcover,
shallowsoils,andabundantexposedrock.
MHTHODS
Forthisstudy,ataxonisconsideredtobeendemicifitsrangeessentiallydoes
notextendoutsidetheInteriorHighlands.Hybridtaxaareexcludedfromthis
list.NomenclaturegenerallyfollowsKartesz(1999).
Wesearchedallavailablesourcesofinformation,includingextensivecon-
ZOLLNERETAL,ENDEMICPLANTSOFTHEINTERIORHIGHLANDS 1783
sultationwithknowledgeableexperts,todetermineglobalrangesofspeciesin
thevascularfloraofArkansas,Illinois,Kansas,Missouri,andOklahoma.This
includedgeneralreferencessuchasKartesz(1999),Krai(1983),Mohlenbrock
(2002),RobisonandAllen(1995),Smith(1988),Steyermark(1963),Taylorand
Taylor(1989),Yatskievych(1999),FloraofNorthAmericaEditorialCommittee
(1993-),andmorespecificpapers(e.g.Tucker1974;Weckman2002).Alsoin-
cludedwerevariouslistsofspeciesofconcernkeptbytheArkansas,Illinois,
Kansas,Missouri,andOklahomaNaturalHeritageprogramsandtheOzark,
Ouachita,MarkTwain,andShawneeNationalForests^.
Oncethepreliminarylistwascompiled,weinvestigatedmanyofthesame
sourcesandadditionalecologicalreferencestodeterminetheplantcommunity
affiliation(s)ofeachspeciesthroughouttheInteriorHighlands.Thisdetermi-
nationinvolveddevelopingageneralplantcommunitylistfortheInteriorHigh-
landsandassigningeachtaxontothemostappropriateplantcommunity.We
usedTheNatureConservancy'sclassificationattheecologicalsystemlevel
(Comneretal.2003),makingecologicalsystemconceptuallyanalogoustoplant
communityasappliedhere.Sometaxawerecharacteristicallyaffiliatedwith
twoormoreecologicalsystems.EcologicalsystemsoftheInteriorHighlands
arelistedinTable2.
RESULTS
Includedbelow(Table1)isanannotatedlistofthe36vasculartaxaendemicto
theInteriorHighlands,arrangedalphabeticallybyfamilyandgenus.Foreach
taxon,oneormorecharacteristicplantcommunitytypesareindicatedinbrack-
etsaftertheplantname,usingthenumbersdesignatedforeachcommunityin
Table2.Foreachspeciesinthislist,wealsoindicatethefamily,physiognomic
profile,distributionpatternwithintheInteriorHighlands-Ozarks(Oz),
Ouachitas(Ou),orboth-andadditionalrelevantinformationandcomments
whereapplicable.TheArkansasValleyisincludedintheOuachitasection.
DISCUSSION
Weidentifiedatotalof36endemicvasculartaxawithintheInteriorHighlands;
therearenoendemicfamiliesorgenera.Thereare24endemicspecies,and12
'inadditiontothetaxatreatedinthispaper,sixspeciesofCrataegus(Rosaceae),CcamllensisSarg.,C.
harveyanaSatg.,C.lanuginosaSafg.datebrosaSarg.,Ciuc/oSarg.,andCAhermopegaeaPalmer,arerecognizedby
Kartesz(1999)asbeingendemictotheregionandotherpotentiallyendemichawthornshavebeenproposed
{e.g.C^ouachitensisPalmer)butSmith(1994)doesnotrecognizethem.EventhoughendemismishighinCrataegus,
wehaveleftthiscomplexandincompletelyunderstoodgenusoffthelist.TherearereportsofHamamelisvernalis
Sarg.(Hammamelidaceae)fromsoutheasternTexasbyCorrellandJohnston(1970),Vines(1977).Nixon(1985),
Joneset.al.,(1997),andTurneretal.(2003),althoughFloraofNorthAmerica(1997)statesthatthisspeciesis
endemictotheInteriorHighlands.Consequently,wehaveomittedHamamelisvernalisfromthistreatment.A
revisionofthegenusTallnum(Portulacaceae)currentlyunderwaymayresultintheadditionoftwoendemic
speciestotheInteriorHighlandsflora.
1784 BRIT.ORG/SIDA21(3)
FiG.I.MapoftheInteriorHighlandsPhysiographicRegion.
endemicsubspeciesorvarietiesofmorewidelydistributedspecies.Mostofthe
endemicplanttaxaintheInteriorHighlandsareontheArkansas,llhnois,Kansas,
Missouri,and/orOklahomaNaturalHeritageprograms"speciesofconcern"lists.
Most158%)of theendemicvascularplantsoftheInteriorhighlandsare
perennialforbs;thisparallelsthephysiognomyoltheoverallvascularfloraof
theregion,aswellastheccoregionsol midcontinentalNorthAmerica.Only
threeendemictaxa(,8%)arcwoody,andthereisasingleendemiclern.Although
onlynineendemictaxa[15%)areannuals,thisisahigherproportionofannu-
alsthaninthetotalnativevascularfloraol theregion,andislikelyreflective
oftheharshconditionsthatcharacterizegladeenvironments,whichharbora
disproportionatecomponentol annualspeciesascomparedtootherhabitats
intheregion.
ZOLLNERETAL.,ENDEMICPLANTSOFTHEINTERIORHIGHLANDS 1785
Table1.EndemicvascularfloraoftheIrTteriorhighlandswithcommunityassociationsinbrackets
(seeTable2),0u=OuachitaMountains,Oz=OzarkPlateau,both=bothsections.
APOCYNACEAE CYPERACEAE
Amsofiiahubrichtii\Noods.[]2]both;perennial Corex/afebracteafaWaterfall[5,6,12]Ou;peren-
forb nialsedge
ASTERACEAE FABACEAE
ichinaceaparadoxa\/a(.paradoxa(J.B.S.Norton) AmorpliaouachitensisWWbuf[12]both;shrub
Britt,[7]Oz;perennialforb FAGACEAE
LiatrAis.Gsrqauyan|8o]sOau(;L.)peMriecnhnxi.avlarf,orrbo;mpcceinrtfearToofrrd,is&- QuerOcuu;satcreerei;folailat(hPoaulmgehr)lHoensgs&thSotouygnhotfft[o1,1b3e]
torfitbhuteioOnuaicnhtihteaNMovoaucnutlaiitnes.Upliftsubsection cQl.ossheulmyarrdeiliat,erdetcoe,notrreevseeanrcchonisnpdeicciaftiecswtihtaht
PolyOmun;iaacnonsusaaltotfoernbs;iskAn.oB.wPnitotnmlaynf&rVo.mBatthees[N1o4-] athrilsiatnasxaonna(isWimloliraemscl2o0s0e3ly|TahffeilgilaotebdalwiptohpuQ-.
vMaocuunltiatienUsp.liftsubsectionoftheOuachita lationislessthan600individuals.
So//c/ogoouoc/7/tens/sC.&J.Taylor[6]Ou;peren- HYDROPHYLLACEAE
nialforb;centerofdistributionintheNova- HydrophyllunibrowneiKrai&Bates[12]Ou;pe-
culiteUpliftsubsectionoftheOuachita rennialforb;centerofdistributioninthe
Mountains. NovaculiteUpliftsubsectionoftheOuachita
l/tYnon/a/effermonn/Engelm.exA.Gray[12]Ou; Mountains.
perennialforb LAMIACEAE
BRASSICACEAE Monarda fistulosa ssp. fistulosa L. var.
Cardamineangustata0£Sc\-\u\z\tSi[.ouachitano stipitatoglandulosa,comb.nov.ined.[6,8]
E.B.Smith[4,5]Ou;perennialforb;known both;perennialforb;thistaxonhasappar-
onlyfrorntheNovaculiteUpliftsubsection entlynotbeenvalidlypublishedatthevari-
oftheOuachitaMountains. etallevel,althoughWaterfall(1970)firstde-
!esquerellafillformisRollins[7]Oz;winterannua scribeditatthespecieslevel,whichwas
forb;restrictedtolimestoneglades,almost conceptuallyendorsedbySmith(1988).
totallywithintheSpringfieldPlainsubsec- ScutellariabushiiBritt.[7]Oz;perennialforb;re-
tionoftheOzarks. strictedtodolomiteglades,withthemajor-
StreptanthusmoculatusNutt.ssp.obtusifolius ityoftheworld'spopulationinthedrainages
(Hook.)Rollins[8]Ou;annualforb oftheCurrent,ElevenPoint,andWhiterivers.
StreptanthussquamiformisGoodman[6]Ou; LILIACEAE
annualforb;knownonlyfromtheNovaculite NemastylisnuttalliiPickering[7]Oz;perennial
UpliftsubsectionoftheOuachitaMountains. forb
CAPRIFOLIACEAE POACEAE
ViburnumozarkenseAshe[5,12,14]both;shrub ElymusglaucusBuckleyssp.mackenzii(Bush)
COMMELINACEAE J.J.N.Campbell[7,8]both;perennialforb
TradescantialongipesE.5.Anderson&Woods. PTERIDACEAE
[4,6]both;perennialforb;althoughknown PellaeaglabellaMett.exKuhnssp.missouriensis
fromboththeOuachitasandOzarks,this (Gastony)Windham[14]Oz;fern;thisisthe
speciesISespeciallycharacteristicinacidic di-ploid,sexualvarietyofawide-ranging
woodlandsondissecteduplandsintheCur- species.Exceptforthespores,itismorpho-
rentRiverdrainage,andrelativelyrareelse- logicallyindistinguishablefromtheapomic-
whereintheInteriorHighlands. ticssp.glabella(Wagneretal.1965).
Tradescantiaozarl<anaE.5.Anderson&Woods.
[4,5,14]both;perennialforb
1786 BRIT.ORG/SIDA21(3)
Table1.continued
RANUNCULACEAE SaxifragapalmefiBush[12]both;perennialforb
DelphiniumnewtonianumDM.Moore[4,5] SaxifmgavirginiensisMichx.var.subintegra
both;perennialforb Goodman[1,1.3]both;perennialforb
DelphiniumtreleaseiBushexK.C.Davis[7]Oz; SCROPHULARIACEAE
perennialforb AgalinisnuttalliiShinners[17[Ou;annualforb
RUBIACEAE PenstemoncobaeaNutt.vai.purpureusPennell
GaliumarkansanumA.Gtayvdt.arkansanum[6,8] [7]Oz;perennialforb;althoughthetypical
both;perennialforb varietyisawiderangingspeciesoftheprai-
GaliumarkansanumA.Grayyar.pubiflorumE.B, riebiome.thisvarietyisrestrictedtoglades
Smith[6,8]Ou;perennialforb;morphologi- oncarbonatebedrockintheInteriorHigh-
cally,thistaxonappearscloselyrelatedtothe lands.
parentvarietyandneedsfurthergenetic VALERIANACEAE
eUpvlailfutastiuobns.ecKtnioonwnofotnhleyOfuraocmhitthaeMNoouvnatcauilnist.e Valebrioatnhe;llaanlnounagliffloorrab(Torr.&A.Gray)Walp.[1]
HousOtuo;nipaeroeunancihalitfaonrab;(cEe.nB.teSrmiotfhd)isTterrrieblulti[o6n,8i]n Valebrioatnhe;llaannnuutatalllfioirb(Torr.&A.Gray)Walp.[1,8]
tchhietaNoMvoaucnutlaiitensU.pliftsubsectionoftheOua- VVaalleerriiaanneellllaapozaolrmkeadnaDyDaylal[1[,71]2]boOtuh;;aannnnuuaallffoorrbb;
SAXIFRAGACEAE centerofdistributionintheNovaculiteUp-
HeucheravillosaMichx.var.cj/tonsona(Rydberg) liftsubsectionoftheOuachitaMountains.
E.B.Smith[12,14]both;perennialforb
TheOuachitaMountainscomprise25%oi thetotalareaol theInterior
Highlands,butsupport81%oltheendemictaxaoftheInteriorHighlands.Four-
teentaxa,representing39%oitheregionsendemicplants,arefoundonlyin
theOuachitaMountains.Fifteentaxa(42%)arefoundinboththeOuachitaand
Ozarkregions,whileseventaxaQ9%))arerestrictedtotheOzarkPlateau.Also
signilicantisthat25%ol theendemicInteriorITighlandslloraisassociated
withtheNovaculiteL)j:)liltsubsectionoltheOuachitas.Thisgeologicsubstrate
withitsglades,woodlands,andstreamcom]olexcsisanecologicalhotspotlor
endemismwithintheInteriorHighlands.
Morethanhalf(58%)oftheendeinicspeciesintheInteriorHighlandsare
associatedwithgladehabitats(acidic,calcareous,novaculite).Asdefinedby
NelsonandLadd(1982),gladesareopenhabitatswithstronglithologiccontrol
thataredominatedbyacharacteristicherbaceousvegetation,withsparsetree
andshrubcover,shallowsoils,andoftenwithabundantexposedrock.These
exposedxericorhydroxcnchabitatshaveextremeenvironmentalparameters
includinglong,usuallyannualdroughtperiodsinthegrowingseason,limited
waterretentionintheshallowsoils,andintensesolarheating.Manygladesare
alsosaturatedthroughmuchofthedormantseason,withfrequentfreeze-thaw
cyclesandassociatedsoilupheavals.Droughtandliremaintainmostgladesin
anearlytreelessstate.
Thelilehistoriesoftheendemicplantsassociatedwithgladesshowdiverse
ZOLLNERETAL.,ENDEMICPLANTSOFTHEINTERIORHIGHLANDS 1787
TABLt2.Characteristicplantcommunityaffiliationsof36endemicInteriorHighlandvascularplants.
NumbersinthepercentcolumnrefertothepercentofInteriorHighlandsendemictaxaoccurring
inthishabitattype.AIIhabitattypeslisted.
CommunityComplex Number Percent
CentralInteriorHighlandsDryAcidicGladeandBarrens 5 14
OuachitaMontaneOakForest
Ozark-OuachitaDryOakWoodland
Ozark-OuachitaDry-MesicOakForest 4 11
Ozark-OuachitaMesicHardwoodForest 5 14
Ozark-OuachitaShortleafPine-OakWoodland 8 22
CentralInteriorHighlandsCalcareousGladeandBarrens 8 22
OuachitaNovaculiteGladeandWoodland 8 22
ArkansasValleyPrairieandWoodlands
CentralInteriorHighlandsandAppalachianSinkholeand
[RepressionPond
OuachitaForestedSeep
12 Ozark-OuachitaRiparian 9 25
13 CentralInteriorAcidicCliffsandTalus 2 6
14CentralInteriorCalcareousCliffsandTalus 5 14
15,Ozark-OuachitaFen
16,North-CentralMaple-BasswoodForest
17 South-CentralInteriorLargeFloodplain 1 3
SoutheasternGreatPlainsTallgrassPrairie
evolutionarytraitsthatallowforsurvivalinthesehabitats,butwhichpresum-
ablyconfernocompetitiveadvantagesinsurroundmgwoodedhabitat.Forex-
ample,Echinaceaparadoxavar.paradoxaandLiatrissquarrosavar.compacta
areshade-intolerant,long-livedperennialswitheitherdeeprootsorwater-hold-
ingsubterraneantissuesandgrowinopenhabitats.TheValerianellaspecies
arevernalannualsthatquicklycoiupletetheirlifecyclesinthespringwhen
conditionsarerelativelycoolandwet;theyareusuallyassociatedwiththose
areasof thegladehabitatthatremainseasonallysaturatedduetowater
seepage.Speciesdistributionsmayalsobecontrolledbyanaffinitytoparticu-
larsubstrateswithspecificlithologicalcharacteristicandmineralavailability.
Forexample,Scutellariahushiiisfoundonlyondolomite;thesegladesarechar-
acterizedbyhighlevelsofsolublecationssuchasmagnesiumandcalcium.
Twenty-eightpercentoftheendemicfloraoccurinriparianhabitats.Three
(Amsoniahubrichtii,Vernonialettermannii,Valerianellapalmeri)oftheten
endemicspeciesfoundinriparianareasareassociatedwithglade-likehabitat
structures,i.e.rocky,openhabitatsalongephemeralorintermittentstreams.
Thesehabitatsarexero-hydric,andmaintainedbyflashystreamflowsandsoil
conditionsthatmakethemseasonallyxericandnearlytreeless.
Wefoundthat22%oftheendemicspeciesarecharacteristicallyassoci-
1788 BRIT.ORG/SIDA21(3)
atcdwithdrypine-oakandoakwoodUmds.ThesepUmtcommunitiesarercki-
rix'clyopen,withsparsetomoderatetreecover,adiverseandwell-developed
herbaceousunderstorywithaprominentgraminiodcomponent,andarehi-
tivelyIrequent(ireregime.Theendemicspeciesassociatedwithwoodlandhabi-
tatsappeartobeintolerantofbothextremeexposureanddeepshade.Solidago
ouachitensis,\ovexample,appearstorequirefilteredsunlightbutisnotfound
inclosedcanopylorestsorthemoreexposedgladehabitats.Woodlandplant
communitiesaremaintained inanopencondition bylireandintermittent
droughthutha\'cpre\'ailingen\'ironmcntalconditionsrelativelylessextreme
anddynamicthantheexposedglades.
AcrosstheInteriorHighlandsregionglades,openwoodlands,andinter-
mittentstreamsformlandscapecomplexesthatarecloselyassociatedonthe
landscape.Theseplantcc~immunitycomplexesarcmaintainedinanopenor
treelessconditionbydrought,fire,andflood.Morethan80%oftheendemic
tloraoltheInteriorHighlandsoccurintheselandscapecomplexes.
Thelistofendemicspresentedmthispaperwillchangeasnewinforma-
tionbecomesax-ailableonplantcommunityassociationsandspeciesdistribu-
tions,andasnewtaxaarediscoveredandothersrelegatedtosynonymy.Hovv-
e\'er,itisnowpossibletocomparetheInteriorHighlandsregionwithadjacent
regionsthatarephysiographicallydifferent.Forexample,the36endemicvas-
culartaxaol theInteriorHighlandsrepresentperhaps2%ofthenativeflora,
butexhibitnopatternsofendemismatorabovethegenuslevel.Infact,the
InteriorHighlandsforallofitsphysiographicuniqueness,includingage,long-
termisolationiromitsmoiety—theAppalachianRegion—anditsreputationas
a"well-knownrefugium"(Meyerf997)showssurprisingly littlefloristic
uniquityIromsurroundingregions.Bycomparison,theWestGulfCoastalPlain
withvirttiallynoreliefandnoantiquity,hasaboutfOOendemictaxa(about
threepercentofitsflora)ofwhichthreeareabovethespecieslevel(MacRoberts
etal.2002).Itisnotknownw^hetherthissamepatternandlevelofendemism
occursamongotherorganismalgroups,buttherearesuggestionsthatendemism
ratesmaybehigherthanamongthevascularflora.Forexample,thereare24
endemiccraylishtaxaintheOzarks(TheNatureConservancy2003);thisrepre-
sentsmorethansevenpercentofNorthAmericanCrayfishdiversityPrelimi-
narydata(Harris&Ladd2003)indicatethattheOzarkregionischaracterized
byanunusuallyhighlevelolundescribedlichentaxa,includingatleasttwonew
genera,hutcurrentdatagapsprecludedetermininglevelsofendemism.
ACKNOWl.HDGMl-NTS
Appreciationisextendedtoseveralpeoplewhocontributedinformationorcom-
mentstothisproject:TheoWitsell,ArkansasNaturalFleritageCommission,
Kaushik Mysorekar,TheNatureConservancy,Phil Hyatt,USForestService,
JulianCampbell,TheNatureConservancy,AlanWeakley,UniversityofNorth
ZOLLNERETAL,ENDEMICPLANTSOFTHEINTERIORHIGHLANDS 1789
CarolinaBotanicalGarden-Herbarium,ScottSimon,TheNatureConservancy,
RobEvans, NatureServe, Ayn Shilsky,The Nature Conservancy,George
Yatskievych,MissouriBotanicalGarden,andRonLance,ChimneyRock.We
alsothankGaryTucker,StariaVanderpool,andtwoanonymousreviewsfor
suggestionsinimprovingthemanuscript.
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