PAPPUS VARIATION IN NORTH AMERICAN ASTERS. I. DOUBLE, TRIPLE AND QUADRUPLE PAPPUS IN SYMPHYOTRICHUM AND RELATED ASTER GENERA (ASTERACEAE: ASTEREAE)

2005·6.9 MB·English

by  John C Semple

PAPPUSVARIATIONINNORTHAMERICANASTERS.
I.
DOUBLE,TRIPLEANDQUADRUPLEPAPPUSIN
SYMPHYOTRICHUMANDRELATEDASTERGENERA
(ASTERACEAE:ASTEREAE)
JohnC.SempleandJenniferLAHood
DepartmentofBiology
UniversityofWaterloo
Waterloo,Ontario,CANADAN2L3G1
[email protected]
ABSTRACT
Thepappustraitsof84taxaofCanadanthus,Ampdasicr.Psi/ac(is,andSymphyotrichum(subtribe
Symphyotrichinae)and14otherspeciesofasterswereexamined.MostspeciesofSymphyotrichinae
hadapappusconsistingofthreewhorls;1)asecondaryinnerwhorlofafewbristles40-85%the
lengthoitheinnerprimarywhorl,2)aprmiar)'outerwhorlofmanybristleswithtapermgends
about90-95%thelengthoftheinnerprimar\'wliorl,and3)aprimaryinnerwhorlofmanybristles
withveryweaklytostronglyclavateends.Inaddition,alewspeciesofSyniphyotrichumhaveaves-
tigialsecondaryouterwhorlofasingleshortbristleonlyabout10-30%thelengthoftheprimary
innerwhorl.InsomespeciesofSymphyotiichumthesecondaryinnerwhorlwasdifficulttodistin-
guishIromtheprnnaryouterwhorlorpossiblywasabsent.InasmallsampleofspeciesofAster,
Dodiingeria,Eurybia,Eucephalus,Galatdla,Herrickia,lonactis,Odemena,andOreostenima,the
pappuswaseithertripleorquadruple.Theshortsecondaryouterwhorlwaspresentinmostspecies
examinedbutwassometimesreducedtoveryfewbristlesorabsentonsomeIruits.hisoinecases,the
secondaryinnerwhorlofmidlengthtaperingbristleswaspresentinsomeindividualsinaspecies
butnotinothers.Thequadruplepappuswithstronglyclavateinnerbristlesappearstobe
plesiomorphicfortheNorthAmericanCladeofthetribeAstereae.Insinglespeciessamplesof
Cnnitaria,Linosyns,andb'diciathepappusdifferedfromthatolotherspeciesexamined.
RESUMEN
Seexaminaronlascaracteristicasdelosvilanosde84taxadeCanadanthus,Ampdastcr,Ps\lactu,y
Symphyotrichum(subtribuSymphyotrichinae)yotras14especiesdecompuestas.Lamayoriadelas
especiesdeSymphyotrichinaetienenunvilanodetresverticilos;\)unvenicilosecundariointerno
depocassedasconel40-85%delalongituddelverticilointernoprimario,2)unverticiloexterno
primarioconmuchassedasdeextremosestrechadosdeaproximadamenteel90-95%delalongitud
delverticilointernoprimario,y3)unverticilointernoprimariodemuchassedasconextremosdesde
debilmenteafuertementeclavados.Ademas,algunasespeciesdeSymphyotrichumtienenunverticilo
secundarioexternovestigialdeunasolasedaaproximadamentedel10-30%delalongituddelverticilo
internoprimario.EnalgunasespeciesdeSymphj'otrichumelverticilosecundariointernofuedificil
dediferenciardelprimarioexternooposiblementeestabaausente.Enunapequenamuestrade
especiesdeAster,DoeUin^eria,Euryhia,Eucephalus,CalaleUa,Herrickia,lonactis,Odemena,y
Oreostemma,elvilanoeratripleocuadruple.Elverticilosecundarioexternocortoestabapresenteen
lamayoriadelasespeciesexaminadasperoestabareducidoalgunasvecesaunaspocassedasoausente
enalgunosIrutos.Enalgunoscasos,elverticilointernosecundariodesedasdetamanomedianoestaba
presenteenalgunosindi\'iduosdeunaespecieperonoenotros.Elvilanocuadrupleconlassedas
SIDA21(4):2141-2159.2005
2142 BRIT.ORG/SIDA21(4)
interioresluertementeclavadaspareceserplesiomorlicoparaelcladoNorteAmericanoclelatribu
Astereae.F.nunasolamuestradeespeciesdeCnnitaiia,Linosyris,yFeliciaelvilanodifenadelas
otrasespeciesexaminadas.
INTRODUCTION
ThesymphyotrichoidastergeneraCanadanthusNesoin,AmpelastcrNesom,
andSymphyothchumNeeshavelongbeenreportedtohaveasimplepappus
withnon-clavatebristles,eitherasspeciesofAsterL.(e.g.,Gray1884;Fernald
1950;Cronquist1955,1968a,1980,1994)orrecentlyasspeciesofCanadanthus,
Ampelaster,andSymphyotrichum(Nesom1994,2000;Sempleetal.2002).In
contrast,someotherNorthAmericanastershistoricallytreatedattimesinother
generaorinA.sttTsensulatohavebeenreportedtohaveadouble(Eucephalus
Nutt., ScricocarpusNees;Gray 1884;Cronquist 1955)ora triple pappus
{DoellingeriaNees;Cronquist1968,1980;Nesom1994;Sempleetal.2002).The
putativelydoublepappusconsistedofashortwhorlofouterbristlesandamuch
longerwhorlofinnerbristles,whiletheputativelytriplepappushadashort
outerwhorlandtwolonginnerwhorls,theouterslightlyshorterandtapering
andtheinnerbristlesclavate.SpeciesolSolidagoL.historicallywerealsocon-
sideredtohaveasimplepappus(e.g.,Gray1884;Fernald1950;Cronquist1968b,
1980;Nesom2000;Sempleetal.1999).However,1loodandSemple(2003)dem-
onstratedthatnearlyallspeciesolgoldenrodshadadoublepappuswithtwo
primarywhorlsoflongbristles(theoutershorterandtapering,theinnerclav-
ate)andatleastsomespecieshadanadditionalsecondaryouterwhorlofafew
veryshortbristles.Thatis,agenusthoughttohaveasimplepappusinfacthad
atriplepappuslike thatreportedforDocUingeria (synonym: Astersect.
TriplopappusTorr&A.Gray;TorreyandGray1841;Seinpleetal.2002).Our
discoverythatgoldenrodshadadouble(orrarelytriple)pappusraisedthepos-
sibilitythatothergeneraofAstereaethoughttohaveasimplepappusmight
alsobedoubleortriple.Thispaperonpappusvariationisoneinascriesbeing
preparedbythefirstauthor'slabtoreportthefindingsol investigationsof
cypselaetraits,includingpappusvariationintheNorthAmericanGladeofthe
Asteraeae(sensuNoyes&Riesebcrg1999).Thepappuswhodterminologypro-
posedbyHoodandSemple(2003;secondaryouterwhorl,primaryouterwhorl,
andprimaryinnerwhorl)isusedthroughoutthispaperwiththeadditionof
newlabelforafourthwhorlnotseeninSolidago,thesecondaryinnerwhorlof
taperedmidlengthbristles.
MATERIALSANDMHTllOnS
Apreliminarysurveywasundertakentoexamineunderthedissectingmicro-
scopethepappusbristlesofoneortwospecimensofrepresentativespeciesol
thesectionsandsubsectionsolSymphyotrichum.Subsequently,amorerigor-
oussurveywasconductedinvolving80taxaandonehybridofSymphyotrichum
SEMPLEANDHOOD,PAPPUSVARIATIONINNORTHAMERICANSYMPHYOTRICHUM 2143
and4speciesofothergenerainthesubtribeSymphyotrichinaeNesomand14
speciesofotherNorthAmericanandEurasianastergeneralistedinTable1.
Observationsweremadeusingadissectingscope(10-70x)oracompoundlight
microscope(20-400x).Thedegreeoftheclavatenessofbristletipswasdeter-
minedusingthe0-4rankingsdescribedmdetailinHoodandSemple(2003).
Atleastfivedifferentfruitsfromeachspecieswereobservedunderthedissecting
microscopeatamaximumof70X;mostobservationsweremadeat30~40x.
Forthemostpart,observationsweremadeonspecimensintheWATHerbarmm,
butadditionalmaterialonloanfromBRIT,CAN,GH,andNY(Holmgrenetal.
1990)wasalsoexaminedtoexpandthenumberoftaxa.Inadditiontoseveral
methodsusedinevaluatingpappusfeatureslistedbyHoodandSemple(2003),
assessmentofthepresenceorabsenceofanyshortsecondaryouterwhorllin-
eartoscalybristlesandotherpappusfeatureswerealsosystematicallyunder-
taken.Thus,Table1hasfivecolumnsofobservationaldataplusacolumnfor
additionalcomments,whileonlylourcolumnswereincludedbyHoodand
Semple(2003).
Observationsonthecompoundmicroscopeweremadefromslidesprepared
asfollows.Foreachspecies,tworayfloretandtwodiscfloretcypselae(withco-
rollasorwithoutcorollasstillattached)weremountedinCytoseal'''^60(low
viscosity)mountingmediumunderacoverslip.Observationsat100-400Xon
thecompoundmicroscopeweremadesimilarlytotheobservationsunderthe
dissectingscopeat30-70x.Observationsmadeonthetwokindsofscopeswere
comparedandanydiscrepancieswereresolvedbyre-examiningspecimens.
DigitalphotomicrographsweretakenusingaNikonCoolPix990camera
manuallyheldagainsttheocularlensofeitherthedissectingorcompound
microscope.Picturesweretakenofspecimensunderthecompoundlightmi-
croscopewitheitherbelowstageorabovestagelighting.Finaldigitalillustra-
tionsweremadeusingCorelDraw12'*'fromdigitalimageseditedwithCorel
PhotoPaintl2®(CorelCorp.).
RESULTSANDDISCUSSION
ThepappusofthemajorityofspeciesoftheSymphyotrichinaeconsistsofthree
whorls(Figs.1-4):1)asecondaryinnerwdiorlofafewintermediatelength,line,
taperingbristlesusuallyabout50-70%ofthelengthoftheprimaryinnerwhorl,
2)aprimaryouterwhorloftapering,non-clavatebristlesthatweregenerally
5-10%shorterthantheinnerwhorl,and3)aprimaryinnerwhorlofveryweakly
tostronglyclavatetippedbristles.Thephylogeneticallymorebasaltaxaof
theSymphyotrichinaeCanadanthusmodestus(Lindl.)Nesom(Figs.lA-G),
AmpelastercarolinanusiWdlt^)Nesom{¥igsAH-K),andAlmutasterpauciflorus
(Nutt.)Love&Love(Figs.2A-E)arealldiploids(2n=18)withx=9chromo-
somalbasenumber(Brouilletetal.2001a,b;Sempleetal.2002).Thesehavea
triplepappuswithnosecondaryouterwhorlofshortbristlesorscalesobserved.
Table1.PappusvariationinsubtribeSymphyotrichinae:Symp/iyofr/c/7umandrelatedgenera.Civ,degreeofclavatenessofinnerbristles(0=notclavateto4=
stronglyclavate):Civ-Tap,clavatealternatingwithtaperedbristles(primaryinnerandouterwhiorls,y=yes,-notobviouslyso);Lgth,primaryouterbristles
shorterthanprimaryinnerbristles;Ovrlp,degreeofoverlappingofbristlesatbase(0=notobserved;1=slightoverlap;2=definiteoverlap);2"''-Out,evidence
forasecondaryouterwhorlofveryshortscaly-bristles.
Taxon Civ Civ-Tap Lgth Ovrip 2"''-0ut Comments
SYMPHYOTRICHINAENesom
CanadanthusNesom(x=9)
C.modestus 1 y y 2 2"'^innerbristles60%of1°inner
AmpelasterNesom{x-9)
AlmAu,tcaasrGthenriaLnouvse(x=9) 2 y y 2"'^inner,few,50%of1°inner
A.pauclflorus 1 y y 2"=inner50-60%ofrinner
PsilactisA.Gray(x=9,4,3)
Rtenuis{x=4) 1 y y heterocarpic,rayfruitepappose;
2""innerbristle40-60%of1°inner
SymphyotrichumNees
subg.Chapmaniani(Semple)Semple(x=7)
5.chapmanii 2 2""inner,few,50-60%of1°inner;
possible2' outerwhorlbristle,oneseen,
fine,30%ofTinner
subgSymphyotrichumsectSymphyotrichum(x=8)subsect.Symp^yofr/c/ium
seriesSymphyotrichum
S.novi-belgli y n 2"''inner,veryfew,70%ofTinner
5.retroflexum 4 v y 2 y 2""^innerbristles,few,70-8%of1°inner;
possible2"^outerbristle,30%of1°inner, o
onlyseenononefruit 3D
S.robynsianum y n 2^'=inner,few,70-80%of1°inner
seriesPunicei(House)Semple
S.elliottii y 1 n 2""inner,few,70-80%of1°inner
Taxon Civ Civ-Tap Lgth Ovrip 2"''-0ut Comments
SS..ppruenniacnetuhmoides yy 2 I2"™-^^iinnnneerr,bfreiws,li6es0,-f8e0w,%4o0f-17°0i%nnoefr1° ooo
subg.Symphyotrichumsect.Symphyotrichum{x 8)subsect.Occ/c/enf(7/e5(Rydb.)Nesom{Foliacei)
S.chilense 3 y y 1 2"'-Mnner,few,75-80%of1°inner
S.eatonii 2 y y 2"^^inner,few,75-80%of1°inner
5.foliaceum 3 y y 2"'^inner,veryfew,80%of1°inner 5
S.jessicae 2 y y 2"°inner,veryfew,70-80%of1°
S.spathulatum 3 y y 2"-inner,veryfew,70-80%of1°
S.subspicatum 3 y y 2""innerbristlesnotseen
subg.Symphyotrichumsect.Symphyotrichum{x- 8)subsect.Heferop/iy///(Nees)Sennple
seriesCordifolii(G.DoninLoudon)Semple
S.anomalum 1 y 1 n 2""^innerbristles,few,80%ofT
S.ciliolatum y n 2"-^innerbristles,few,70-80%of1°
5.cordifolium 1 y n 2™"^innerbristles,few,70%of1°
5.drummondii 1 y n 2"-^innerbristles,few,70%of1°
S.shorta 1 y 1 n 2"'"innerbristies.few,70%of1°
S.texanum 1 y n 2"=innerbristles,few,70-80%of1°
S.undulatum 2 y n 2"''innerbristles,few,80%of1°
S.iirophyllum y n variablebristlelengths;2"'^innerbristles,
few,60-70%of1°;1°outer85-90%of1°
innerseriesConcinni(Nees)Semple
S./oeve 2 y y 2"''innerbristles,few,70-80%of1°
5.oolentangiense 3 y y 2 2"^^innerbristles,few,70-80%of1°
S.attenuatum y 2"'^innerbristles60-70%ofinner
subg.Symp/iyofr/c/iumsect.Symphyotrichum{x 8)subsect.Dumosi(Torr.&A.Gray)Nesom
S.boreale y 2"''innerbristles,few,60-70%of1°
5.dumosum
var.dumosum 1 2""inner,0-few,70-80%of1°inner
var.Strictior 2 2"'-"'inner,veryfew,70%of1°inner
Table1.(continued)
Taxon Civ Civ-Tap Lgth Ovrip 2"''-0ut Comments
subg.SymphyotrichumsectSymphyotrichum(x=8)subsect.Dumos/(Torr&A.Gray)Nesom(continued!
5.eulae 3 y y n 2"^innerbristlesnotseen
S.lanceolatum
subsp.hesperium 1 y y- o y 2""^innerbristles,few,50-60%of1°;2""^
outbristle,oneseen,10%of1°subsp.
lanceolatum
vvvaaarrr.^/hliniatrnescruietooirclaautluem yyy 11 222"^""'"iiinnnnnneeerrrbbbrrriiissstttllleeesss,,,fffeeewww,,,877000%%ofoof1f°Tr
vaf.latifolium y 2^=innerbristles,few,80%of1°
S.lateriflorum
var.lateriflorum y 2"^innerbn5tles,few,80%of1°
yar.angustlflolium y 2"^^innerbristles,few,80%of1°
S.nahannlense y 1 2^°innerbristles50-70%of1°inner
S.praealturv
vat.angustior 2™'innerbristles,veryfew,70-80%of1°
inner
yar.praealtum 2'=innerbristles,few,80%of1°
5.ontarione
yar.ontarione y 1 n 2""innerbristles,few,40-80%of1°
S.racemosum y n 2"=^innerbristlesnotseen;smallfruit
5.simmondsii y 1 n 2'""innerbristles,few,70%of1°
S.tradescanti y n 2™innerbristles,few,80%of1°
subgSS.ywmeplshhyaotrichumsect.Symphyotrichum{x-- subsect.Porterianiy(Rydb.)Nesom1 n 2"'^innerbristles50-70%of1°inner
S.depauperatum y n 2"innerbristles,0-few,80%of1°
S.parviceps y n 2"=innerbristles,few,60-70%of1°
S.porterI 2 y y n 2"=inner,0-few,60-70%of1°inner
Taxon Civ Civ-Tap Lgth Ovrip 2"''-0ut Comments
3»
S.pvvlaaltor.,sppuriimlnogslueim 22 yy 1 22""^'^-iinnnneerr,b0r-ifsetlwe,s,500--f6ew0,%8o0f%1°of1° OO
5.priceae 2 y 2"'-'inner,veryfew,80%of1°inner
sect.Conyzopsis(Torr.&Gray)Nesom(x=7)
5.ffondosum y 2"''innernotobvious;1°bristlesfineand
ofslightlydifferentlengths
S.ciIlatum y 2"'^innernotobvious;1°bristlesfineand
ofslightlydifferentlengths
S.laurentianum 1 y y 2"-innernotobvious;1°bristlesfineand
ofslightlydifferentlengths
sect,Turbinelli(Rydb.)Semple(x=48derivedfromx=8)
5.turbinellum 1 y y 2"-inner,1-few,70-80%of1°inner
subq.Ascendentes(Rydb.)Sempie(x=13,21)
S.ascendens 3 y y 2"'innerbristles,few,60-70%of1°
S^defoliatum 1 y y 2""'inner,veryfew,80%of1°inner
subg.Virgulus(Raf.)Nesom(x=5,4)sect.Concolores(Torr,&A,Gray)Nesom
S.sericeum 1 y y 2"'^innerbristles,few,60-70%of1°
inner;T'^outerbristle,oneseenonone
fruit,25%of"inner
S.pratense 1 y y 2"'-innerbustles40-80%of1°inner
5.cvoanrc.ocloonrcolor 1 y y n 2"%nnerbristles,few,50-60%ofr
var.divestitum 1 y y n 2"''innerbristles,few,60-80%of1°
S.plumosum 1 y y 1 n 2'"'innerbristles50-80%of1°inner
subg.Wrgu/us(Raf.)Nesom(x=5,4)sect.Grand/f/on(Torr.&,A,Gray)Nesom
subsect.Grandiflori(Torr.&A.Gray)Nesom
S.campestre 3 y y 2"%nnerbristles,few,40-70%ofT
S.fendleri 2 y- y 2"%nnerbristles,few,50-60%ofr
Table1,(continued)
Taxon Civ Civ-Tap Lgth Ovrip 2''"'-0ut Comments
subsect.Grano'i//o/-/(Torr.&A.Gray)Nesom(continued)
S.grandiflorum 2 y y 1 n 2''"-innerbristles,few,60-70%of1°
5.oblongifolium 2 y y n 2"'innerbristles,few,60-80%of1°
S.yukonense 2 y y 1 y singleshort2'"'outerbristleseen;
2""^inner
bristles40-60%vfine;lowerbarbsof
1°bristlesanthocyanotic
subsect.MexicanaeNesom
5.moranense 3 y y 2"^innerbristles,few,50-70%of1°
subg.5V.itrngluilnuesat(uRamf.)Nesom(x=5,4)sect2.Pafenfes(Torry&A.Gray)Nesyom 2"=innerbristles,few,60-70%of1°
subsect.Patentes(Torr.&A.Gray)Nesom
5.patens
vai.patens 3 y y 1 n 2"^-*innerbristles,few,60-80%of1°
yar.patentissimum 3 y y 2 n 2"^innerbristles,few,70-80%of1°
subSS5.e.pcgthe.lo6orrggaicif/oailnyiupum/m7y///(Torr.&A.Gray)Ne3]som yy yy 21 nn 22""'="iinnnneerrbbrriissttlleess,,ffeeww,,5700-%70of%1o°f1°
5.adnatum 2 y y n 2"'^innerbristles,few,50-70%of1°
subg.SW.rwgaiut/eur!s(Raf.)Nesom(x=5,4)sect.1Po/y//gu/;(Semyple&Brouillet)ySempie 1 n 2""^innerbristles,few,50-80%of1°
S5..nXoavmaeet-hanygsltiianeum -- yy 2 nn 22""^=iinnnneerrbbrriissttlleess,,ffeeww,,5500--8700%%ooff11°°
subg.Virgulus(Raf.)Nesom(x=5,4)sect.fr/co/c/e;(Torr.&A.Gray)Nesom
S.encoides o
subsp.encoides 2 y y 1 2"'^innerbristles,few,70-80%of
subsp.ponsum 1 y y 1 2''°innerbristles,few,70-80%of
S.falcatum 2 y y 2""innerbristles,few,70-80%of
"
Table1.(continued)
Taxon Civ Civ-Tap Lgth Ovrip 2"''-0ut Comments
subg.Astropolium(Nutt.)Semple(x=5) oo
S.subulatum
war.subulatum y n notcleariyinthreewhorls;2'""-*inner
bristles,veryfew,70-80%of1°
S.tenuifolium
vaf.tenuifolium 1 y y n 2"'^innerbristlesnearlyaslongas1°outer
bristles,ornotpresent
EXAMPLESOFOTHERASTERGENERAOFTHENORTHAMERICANCLADE
Doellingeriaumbellata
var.umbellata 3 2'"'outerbristles,many10-15%of1°
innerbristles
Bucephalusengelmannii 4 2'"-'outerbristles,few,linear,10-20%of
1°innerbristles;someindividualshave
a2""^innerwhorlofbristles35-75%of
1°innerwhor
Eurybiamacrophylla 2"^outerbristles,veryfew,10-15%of
innerbristles;someindividualshavea
l"-^innerwhorlofbristles50-60%of1°
innerwhorl
Hernckiaglauca y 22'"""'^^oiunnteerrbbrriissttlleess,,fveewr,y5f0e-w8010%-o2f5%r;inner
tonactislinariifolia y 2""outerbristles,many10-20%of1°
innerbristles;someindividualshavea
2'"'innerwhorlofbristles35-75%of1
innerbristles
Odemenareticulata 2"=outerbristles,few,10-20%ofinner
bristles;2"'^innerbristlesfew,40-60%of
1°inner
Table1.(continued)
Taxon Civ Civ-Tap Lgth Ovrip Z'^'^-Out Comments
EXAMPLESOFOTHERASTERGENERAOFTHENORTHAMERICANCLADE(continued]
Oreostemmaalpigenus
ssp.haydeni 3 y y 2 y 2""outerbristles,few,10-15%ofinner
bristles;2'-innerbristles40-60%of1°
innerbristles
EXAMPLESOFBASALGRADEASTERS
Asteramellus y y 2 2™'outerbristlesveryfew,10-30%of1°
inner;2""innerbristlesfew,50-80%of1°
inner
Asterageratoides
suhsp.leiophyllus 1-2 i2'n'n^eoru;t2e"rbirninsetlresbrviesrtlyesfefwe,w2,05-02-56%0%ofo1f°
1°inner
Asterscaber 2i"n"neoru;t2e"rbirninsetrlesb,rifsetwl,es,15fe-w3,54%0-of701%°of
1°inner
Galatellapunctata 2"''outerbristlesveryfew;ca.30%of1°
inner;2"innerbristlesfew,50-60%of
1°inner
Crinitarialinosyris whorlsgradeoutertoinnerandnot
clearlydiscontinuous;2''outerbristles
veryfew,30-40%of1°inner;I'inner
bristles,50-60%of1°inner
Linosyrisvillosa 1? numerousbristle,70plus;whorlsgrade
outertoinner,shortestouterbristles
15%thelengthofthelongestinner; oso
innermostbristlesonlyweaklyclavate
Feliciaamelloides possiblytwowhorls,somebristles
narrowlyclavate,somevariationin
length;noshorttomidlengthbristles