Syst. Biol. 51(3):389–409, 2002 DOI: 10.1080/10635150290069869 Classication of Apocynaceaes.l. According to a NewApproach CombiningLinnaean and Phylogenetic T axonomy BENGT SENNBLAD1 AND BIRGITTA BREMER Department of SystematicBotany, Evolutionary Biology Center (EBC),Uppsala University, Norbyv.18D, SE-752 36 Uppsala,Sweden Abstract.— Anew approachto anomenclatural system,including elements fromboth Linnaean and phylogenetic nomenclature, is proposed. It is compatible with the existing Linnaeansystem, includ- ing“ standardnames” corresponding to principal andsecondary ranks, and uses avariantof the denitions fromthe Phylocode system.A new infrafamilial classication, usingthis nomenclatural approach,of the Apocynaceae s.l.(i.e., including the Asclepiadaceae) basedmainly on analysesof rbcL and ndhFdatais discussed. Twenty-one tribes andfour ranklesstaxa are de ned. [Apocynaceae s.l.; classication; Linnaeannomenclature; ndhF;nomenclature; phylogenetic nomenclature; phylogeny; rbcL.] Discussionabout different nomenclature The Phylocode systemaims at explicitly systemsin recent literaturehas been in- binding namesto speci c clades;the name tense (e.g., de Queirozand Gauthier ,1992, of ataxonis tightly coupled toa specic 1994;Schander andThollesson, 1995; Bryant, clade(or a specic ancestor)through a def- 1996,1997; de Queiroz,1996, 1997a; Liden inition.Three different kinds of denitions andOxelman, 1996; Reveal, 1996; Cantino (node-based, stem-based,and apomorphy- et al.,1997; Liden et al.,1997; Moore, 1998; based;e.g., de Queirozand Gauthier, 1992; Schander,1998; Sereno, 1999).A new nomen- Cantinoand de Queiroz,2000) have been claturesystem, termed the Phylocode or proposed.Because the Phylocode system phylogenetic taxonomy(de Queirozand abandonsranks, it is (with itspresent de- Gauthier,1992;Cantino and de Queiroz, scription)incompatible with the Linnaean 2000)has been proposed,challenging the system. traditionallyused “Linnaeansystem” (e.g., Bothsystems have certain advantages Greuter et al.,1994). Applications of phyloge- asa communicationtool in biology:The netic taxonomyto plantsystematics include, Linnaeansystem has a morestable set of forexample, classications of the Lamiaceae namesin use (but the exactcircumscrip- (Cantinoet al.,1997), Ericaceae (Kron, 1997), tionsof their correspondingtaxa may vary), Malvaceae(Baum et al.,1998), and Scrophu- whereasthe phylogenetic systemprovides lariaceae(Olmstead et al.,2001). moreexact de nitions, thus reducing in- In the Linnaeansystem, nomenclature stabilitycaused by subjective changesin andclassi cation (circumscription) are not taxoncircumscriptions (e.g., splittersand stronglycoupled. Namedtaxa are xed lumpers). In addition,the principal ranksof totwo reference points:the type (type the Linnaeansystem provide universalstan- genus/species or,in the caseof species, type dardnames that are important, for example, specimen) andthe rank;the only mandatory fortextbooks, databases, and oras. rankis genus (Greuter et al.,1994; in prac- Weproposea compromiseapproach that tice,further ranksare often treatedas manda- combinesthe advantagesof the twosystems. tory).An exactcircumscription of the taxon Itis compatible with the systempresently in isnot required; the only restrictionis that a use—the Linnaeansystem— in using asys- taxoncannot include anothertaxon with the temof hierarchicstandard names (compare sameor higher rank.Nevertheless, a listof in- with“ primaryranks” in the Linnaeansys- cluded taxais often addedin classications tem) andtypes, but italso adopts a variantof oftaxa above species level. the denitions from the phylogenetic system toreduce the impactof subjective changes 1 Currentaf liation andaddress for correspondence: in circumscriptions.Because the mainaim StockholmBioinformatics Center/Center forGenomics withthe present studyis to present anew andEvolution, KarolinskaInstitute, SCFAB,SE-106 91 tribalclassi cation of the angiospermfam- Stockholm,Sweden; E-mail: [email protected] ily Apocynaceaes.l., we will mainlyconcern 389 390 SYSTEMATICBIOLOGY VOL. 51 ourselveswith family/ tribal-level plantclas- Sennblad andBremer, 1996; Civeyrel et al., sication. Likewise, ouruse ofthe termthe 1998;Potgieter and Albert, 2001),three Linnaeansystem mainly refers tothe In- tribeswere monogeneric,and the mono- ternationalCode of Botanical Nomenclature phyly of one tribe hasnot been evalu- (ICBN; Greuter et al.,1994). W ewill not ated.The studyof Sennblad et al.(1998) discussspecies-level nomenclature,nor that wasaimed mainly at the tribe Wrightieae of extincttaxa (see, e.g.,de Queirozand (Apocynoideae) sensu Leeuwenberg (1994a) Gauthier,1992;Eriksson et al.,1998; Mishler , but alsoincluded representativesof the other 1999). tribesof the Apocynoideae,as well asof the The Apocynaceaes.l. belong tothe or- Asclepiadaceae.Sennblad et al.showed that der Gentianalesand have a mainlypantrop- none ofthe described tribeswithin the Apoc- ical/subtropicaldistribution, with a few ynoideae ismonophyletic and suggested temperaterepresentatives. The family com- areclassication of the Wrightieae sensu prisesmany well-known ornamentalssuch Leeuwenberg (1994a)into the Wrightieae,the as Nerium (oleander) and Hoya (wax ower). Nerieae, andthe Malouetieae. The plantsare typically laticiferous and pro- The infrafamilialclassi cation of Ascle- duce variousalkaloids and cardenolides, piadaceaeproposed by Brown(1810) when someof whichhave medical properties. The describing the family hasbeen followed mostwell-known example is Catharanthus by mostsubsequent authors(Liede and (roseperiwinkle), which containsvinblas- Albers, 1994)and comprises three subfam- tine andvincristine, compounds now used ilies, of which the Periplocoideae andSe- worldwideto treatchildhood leukemia. camonoideaeare monotribal and the As- The family Asclepiadaceaewas segregated clepiadoideae usually comprise ve tribes. fromthe Apocynaceaes.l. by Brown(1810). An exception fromthis traditional view is Although someauthors have questioned this the classication of Swarupanandanet al. separation(e.g., Demeter,1922;Safwat, 1962; (1996),which reduced the number of tribes Judd et al.,1994; Struwe et al.,1994), most ofthe Asclepiadoideaeto twoand included classications subsequent tothat of Brown the Secamonoideaeas a thirdtribe in the havefollowed his “ two-family”treatment. Asclepiadoideae.Furthermore, a revisionof Molecularstudies of the Apocynaceaes.l. the Periplocoideae by Venter andV erhoeven (Sennblad andBremer, 1996; Civeyrel et al., (1997)recognizes three tribesin thissubfam- 1998;Potgieter and Albert, 2001)have indi- ily.The monophyly of the Asclepiadaceae catedthat the Asclepiadaceaeform a sub- isuncertain; in the studyof Sennblad and cladeof the Apocynaceaes.str .,thusrender- Bremer (1996),however ,the subfamily ing the Apocynaceaes.str .nonmonophyletic. Periplocoideae,itself monophyletic,did not These studiesalso indicated major problems forma monophyleticgroup withthe other withthe infrafamilialclassi cation in the two twosubfamilies (sensu Liede andAlbers, families.A detaileddiscussion of different 1994),whereas in the studyof Civeyrel classications of the Apocynaceaes.str .and et al.(1998) the three subfamilies didform a the Asclepiadaceaeis given in Sennblad and monophyleticgroup. The studyof Civeyrel Bremer (1996),and only ashortreview will et al.(1998) also indicated that the tradi- be given here, concentratingon the mostre- tionalSecamonoideae is monophyletic with centclassi cations and results from molecu- apositionas sister to Asclepiadoideae (see larstudies. alsoSennblad andBremer ,1996;Potgieter Since the classication of Schumann andAlbert, 2001).The traditionalAsclepi- (1895),the Apocynaceaehave tradition- adoideaereceive goodsupport (Sennblad allybeen divided intotwo subfamilies, the andBremer ,1996;Civeyrel et al.,1998; Plumerioideae andthe Apocynoideae,and Potgieterand Albert, 2001).Of the tribes approximatelyinto 12 tribes and 27 sub- of the Asclepiadoideaein the classication tribes(Pichon, 1948a,b,c,1950; Leeuwenberg, of Liede andAlbers (1994),Asclepiadeae 1994a).The studiesby Sennblad andBremer andMarsdenieae have been shownto be (1996)and Endress et al.(1996) showed that nonmonophyletic. boththe Plumerioideae andApocynoideae The ndings ofthe molecularstudies indi- arenonmonophyletic. Four of the tribes catedabove and also from a previous version ofthe Plumerioideae havebeen shownto of thispaper (included in the Ph.D. thesis be nonmonophyletic(Endress et al.,1996; ofB.S.,1997; see alsoSennblad andBremer , 2002 SENNBLADAND BREMER—CLAS SIFICATIONOFAPOCYNACEAE 391 2000)were summarizedand developed fur- TABLE 1.Classi cation of the Apocynaceae s.l.and therby use of morphologyin the mostre- samplingof taxa.Classi cation areaccording to Endress centclassi cation of the Apocynaceaes.l. by andBruyns (2000). Endressand Bruyns (2000).The ve tradi- RAUVOLFIOIDEAE tionalsubfamilies were kept, but 19newly Alstonieae Melodineae recircumscribedtribes were alsorecognized Alstonia R.Br. Craspidospermum A.DC. (see Table 1). Aspidosperma Mart. Diplorhynchus Ficalho et Zucc. et Hiern However,the resultsof the present study Vallesia Ruiz Melodinus J.R. Forst. indicatethat although the classication of et Pav. et G. Forst. Endressand Bruyns (2000)are a majorad- Vinceae Hunterieae vancein makingthe classication congru- Catharanthus G. Don Picralima Pierre ent withcurrent best estimates of phylogeny , Kopsia Blume Pleiocarpa Benth. Ochrosia Juss. Plumerieae problematiccases still need revision.Fur- Rauvola L. Allamanda L. thermore,for