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BLUMEA 42 (1997) 1-106 A skeletalrevision ofNepenthes(Nepenthaceae) Matthew Jebb & Martin Cheek Summary Askeletal world revision ofthegenus ispresentedto accompanya familyaccount forFlora Malesi- ana.82 speciesarerecognised,ofwhich 74occurin theMalesiana region.Sixspecies aredescribed asnew,onespecies israised from infraspecificstatus, andfive species arerestoredfrom synonymy. Manynamesaretypifiedforthe firsttime. Three widespread,orlocally abundanthybrids are also included.Full descriptionsaregivenfornew(6)orrecircumscribed (7)species, andemended descriptions ofspecies aregiven where necessary (9). Critical notes are given for all the species. Little known and excluded species arediscussed. An index toall publishedspecies namesand anindex of exsiccataeis given. Introduction Aworld revisionofNepenthes was lastundertakenbyMacfarlane(1908), andare- gionalrevision fortheFloraMalesianaarea(excluding thePhilippines) wascompleted by Danser(1928). Thepurposeofthispaperis toprovide askeletal revision, cover- ing issues relating to Nepenthes taxonomy whichwouldbe inappropriate in thetext ofFloraMalesiana.For themajorityofspecies, only theoriginal citationandthatin Danser(1928) andlaterpublications is given, sinceDanser's (1928)work provides a thorough and accuratereferencetoallearlierliterature. 74species arerecognised intheregion, andthree naturally occurring hybrids are also coveredfortheFloraaccount. Thehybrids N. x hookerianaLindl.andN.xtri- chocarpa Miq. arefoundin Sumatra,PeninsularMalaysia andBorneo,althoughrare withinpopulations, their widespread distributionnecessitatestheirinclusionin the Flora. By and large otherhybrids are rare and sporadic, withthe exception ofN. xkinabaluensis, whichformsadiscretehybridswarm onMtKinabalu. Six newspecies aredescribed: Nepenthes argentii fromthePhilippines, N.aristo- lochioidesfrom Sumatra, N. danserifrom Waigeo Island(New Guinea), N. diatas from Sumatra, N. lamii fromNew Guinea, and N. murudensisCulham ex Jebb& Cheekfrom Sarawak. Onenew combinationis made;N. macrophylla (Marabini) Jebb&Cheek, formerly asubspecies ofN. edwardsianaLowex Hook.f. Three species synonymised by Danser (1928): N.eustachya Miq.,N. ramispina Ridl., andN. sumatrana (Miq.) Beck, andone synonymised by Macfarlane(1908): N. hispida Beck, arerestored. Nepenthes pectinata Danseris alsorestored.Anum- berofnames arerelegated tosynonymy,andlectotypifications havebeenundertaken wherenecessary. 1) DepartmentofBotany,Trinity College,Dublin 2,Ireland. 2) Herbarium,National BotanicGardens,Glasnevin,Dublin9, Ireland. 3) RoyalBotanicGardens,Kew, Richmond,Surrey, TW93AB, U.K. 2 BLUMEA Vol. 42,No. 1, 1997 LikeDanser werecognise nosubspecies or varieties.Collectionsremain few, with 9species being known fromthetypecollectionalone.Afurther10species are restrictedto single mountains, ormountaingroups,andonly 10oftheremaining taxa extendbeyond asingle island. Eight species ofNepenthes donot occurin theFloraMalesianaregion: Nepenthes madagascariensis Poir. andN.masoalensisSchmid-Hollinger in Madagascar,N.per- villeiBlumeintheSeychelles, andN. distillatoriaL. in Sri Lanka. InNorthernIndia N.khasianaHook.f.and in IndochinaN.anamensisMacfarl.andN. thoreliiLe- comte. Nepenthes vieillardiiHook.f. is foundinNew Caledonia(specimens from NewGuineaformerly placed inthis species are now placed in thenew species N. lamii). PREVIOUS REVISIONS Therehave been three major monographic revisions of the genus.Firstly Joseph Hooker's 1873account inDeCandolle'sProdromus, atwhichtimethegenusnum- bered 33 species. Heplaced the Seychelles species N. pervillei in a monotypic sec- tionAnourosperma. Macfarlanerevised thefamilyforEngler's Pflanzenreich(1908), recognising 58species. Danser's treatmentofthe genusfortheNetherlandsIndies treated51 species foundintheformerDutchEastIndiesandadjoiningareas. Historically, Nepenthes taxonomy hasbothbenefitedandsufferedfromthehorti- cultural desirabilityoftheseplants, andspecies oftenentered herbariaviathegreen- houses ofEurope. Collectorsoftypematerial such as DavidBurke(1880), Charles Curtis (1878-84) and Frederick Burbidge (1877-78) were also collectors oflive plants forMr. HarryVeitchofChelsea, oneoftheforemostgrowersofNepenthes at thattime.Bull Nurseries werealsointhetradeatthetime, andtheircatalogues listan impressive range ofspecies atoutrageousprices. SirHugh Low,who was Rajah JamesBrooke'spersonal secretary atthistime,sent manyplants tohis fatheratthe Clapton nurseriesinLondon. MaxwellMasters andFrederickBurbidge appeartohavebeen regularcorrespon- dentsofSir Joseph Hooker at Kew, soliciting his opinion on specimens they had growing in nurseries.During thisperiod (1881-1890) anumberofspecies and cultivars were published intheGardeners' Chronicle.Thisledto uncritical descriptions, as well as unsatisfactory informationon provenance (N. burkeiMast., N. curtisii Mast,andN. stenophylla Mast,wereall basedon cultivatedmaterialalone). WithoutdoubtDanser's masterfultreatment in 1928remainsthemostthorough, and upto datetreatment ofthe genus.He retained35 species in theformer Dutch EastIndies and adjoining areas, adding 17, to give a then worldtotal of65 species. Hemadeafirstattempt at aphylogenetic treatment,with six informalspecies groups. TAXONOMY SINCE DANSER Littlecollectinghasoccurred sinceDanser'srevision (1928), anditwas not untilthe 1970'sand 80's thatspecialist collectorsbegan publishing newspecies onanadhoc basis. Horticulturalinterestintheseplants hasbeenthemostimportant factorinstim- ulating thisprogress. SinceDanser (1928), 36 namesofspecies, subspecies, and M.Jebb& M.Cheek: Skeletal revision ofNepenthes 3 naturally occurring varieties and hybrids havebeen published (including two further species byDanser); 18oftheseareretainedhere.Anumberofspecies namesremained invalidlypublished fora numberofyears(N. adnataTamin& M.Hottaex Schlauer, N. dentataSh.Kurata,N. globamphora Sh.Kurata&Toyosh. andN. macrovulgaris J.R.Turnbull& A.T.Middleton). In 1984,two setsofcompeting nameswere published forthree Sulawesi species. On the6th February, Kurata (1984a) published N. eymaeandN. rubromaculata(a homonym ofanineteenthcentury hybrid). On the10thFebruary TurnbullandMid- dleton(1984) published N. glabrata (a validnameforN. rubromaculata), N. hamata andN. infundibuliformis (=N. eymae).On the7th March,Kurata(1984b) published N. dentata(=N. hamata). The question ofdates is complicated by thefact thatthe firsttwo publications weresubtitledwiththeclaimthattheywere 'preprinted'. Theac- tualdatesatwhichthesepublications were 'widely' availableis difficultto determine, anditis unclearwhethertheTurnbullandMiddletonpre-publication was infactdis- tributedbeforeeitherofKurata'spublications. Severalregional revisions have appeared, including Kurata'sNepenthes ofMount Kinabalu(1976), Shivas's PitcherPlantsofPeninsularMalaysia& Singapore (1984), Tamin& Hotta's Nepenthes di Sumatera(1986), Jebb'sNepenthes in NewGuinea (1991) andPhillipps &Lamb'sPitcher PlantsofBorneo(1996). JumaatAdam has revised theBorneanspecies, buthis species descriptions are scatteredinthelitera- ture,andnoreviewoftheentireflorahasbeenundertakenexcept intheform ofan ecologicalpaper(Adam etal., 1992). HORTICULTURE AND HYBRIDS Thereare alarge numberofcollectorsand growersof Nepenthes andmanyspecies arenow widely cultivated.Several newslettersandanelectronicbulletinboard(CP, servedby [email protected]) are dedicatedto thecultivationand descrip- tionofcarnivorousplants. Anumberofnew species, as wellas numerous cultivars, have beendescribedinthesenewsletters. Nepenthes cultivationlastreacheda zenith attheendofthe 19thcentury. Pollenandseed exchange is now commonpractice in bothconserving species and developing new hybrids. Theentiregenus is listedunderAppendix IIoftheCITES convention, and two species (N.khasianaandN. rajah) are listedasAppendix Ispecies. Nepenthes rajah andN. clipeata aretheonlyspecies knowntobedirectly endangered by specialist collectors. Over280 hybrid names have been published, 193 involving more thantwo par- ents. 34species are involvedin thesecrosses, although 75%ofthe crosses involve N. rajflesiana and/orN. maxima. Some hybrids havebeengenerated through multi- ple crosses ofuptosix species (Schlauer, 1994). ECOLOGY Nepenthes species occur mostly locally, often sporadically, andthenoften in large numbers. They are found from sea-level to 3,500 m, but most commonly between 1,500 to2,500m. They canbefoundin practically every vegetation type,butespe- 4 BLUMEA —Vol. 42, No. 1, 1997 cially onthin orinfertilesoils (either fromchemistry, waterlogging orlow nutrient levels), where thecanopyis sparseor thin.They occurleastcommonly inclosedfor- est. They are common on whitepodsolic soils, wet peatysoils, orheavily leached volcanic soils, butarealmostentirely absentfromrichalluvialorclay soils. They are commonly encounteredalong riverbanks, on abrupt, open,orrocky ridge tops, and in wet mossy forest. A numberof taxa are restricted to ultrabasic, serpentine soils (N.argentii, N. burbidgeae, N. danseri, N. xkinabaluensis, N. macrovulgaris, N. rajah andN. villosa), whilstothers appearto berestricted to limestonerocks (N.campanulata, N. mapuluensis, andN. northiana). Somespecies are foundin a widerangeofhabitats, and appearto thrivebest in disturbedhabitats(N. mirabilisandN. gracilis). Afewspecies are capableofsurviv- ing in quitedenseshade(N. ampullaria, N. macfarlanei, andN. mirabilis).Mostspe- ciesare shrubby scramblersorclimbersofopenvegetation. Afewspecies regularly grow as epiphytes (N. inermis, N. insignis, N. reinwardtiana,and N. veitchii). HABIT Young Nepenthes plantsproduce theirfirstpitchers whilestillminute, andtheheight ofthesepitchers maybe only2to3 mm.As theplant develops, successive pitchers are larger,andbegin toacquire theirspecific characters. Plantsofall species begin lifeas low rosettes. Thestems are highly condensed andproduce leaveswithstraight tendrilsand incurving, globosepitchers oftenwith prominent, fringed wings. As theplantgrows thestemmaybegin toclimb, produc- ing longer internodesand leavesin which thetendrilis coiledandthepitcher now curves outwardsfrom thetendril, becoming morecylindrical orinfundibulate, and thewingsbecomemuchreducedorabsent. Sideshootsfromthemainstemreiterate thisprocess, initially formingrosettes bearing pitchers ofthe lowertype, andthen pitchers oftheuppertypeonce theshootbegins toelongate (Jebb, 1991).Thesetwo pitcher typesare herereferred toas Upper andLowerpitchers. Danser(1928) distinguished pitchers oftherosette,shortshootandclimbing stem. We considerthatthe distinctionis not always clearcut.Ourdescriptions treatapparentintermediateswhere they havebeenobserved. Nepenthes species can beremarkably polymorphic, bothwithinandbetween indi- vidualsandpopulations. Variationinpitcherstructureand colourationcanbestriking. Sometimesthesedifferencescanberelated tosoil type (Phillipps &Lamb, 1996),although more usually itis lightlevels thatare most significant. The dimorphy ofthe pitchers apparently followsthesamepatterninall species. Relativetothelowerpitch- ers, theupperpitchers becomelonger and narrower and bearreduced wings; inter- nally thewaxy zonebecomesreduced, andthebasalglandular zonecanreachalmost to the level oftheperistome; theperistome is narrower, andoften not as markedly toothed; the spurnearthe baseofthelid becomes smallerand lessbranched. This dimorphy often leads to confusionas to how many species arepresent at a site. Selectionofherbariummaterialmay bestrongly biasedto themost extreme forms. Thustotheinexperienced, youngandmature plants may give the appearanceofbe- longing to quiteseparate species. M.Jebb& M.Cheek: Skeletal revision ofNepenthes 5 A distinctivearchitecture is found inN. ampullaria andN. pectinata, wherethe lowerpitchers are almostglobose, withmuch reduced leafblades, whilethe upper leaveshavelarge blades, andtheupperpitchers are usually not developed, beingre- ducedtoamereswelling atthetendriltip. MORPHOLOGY Venationindicatesthatthespurofthepitcher is thetrue leafapex,the lidbeing the only organtolack amid-rib(Hooker, 1859). Thebladeoftheleafmaybesessile or petiolate to themainstem.Petiolesare often winged, and insome species the leaf base is dccurrentoradnatetothestem.The leavesofclimbing stemstendto bemore petiolate thanthoseoftherosette stemsin allspecies. Atfertilenodes, however, the leaves canbe quiteaberrant,often beingsessileor moreabruptly truncate atthebase than thenorm.In somespecies theleafbladeshows greatvariationinsize ontheone plant; eitherbeing smalleronthe rosetteleaves (N. ampullaria) or larger there(N. maxima). Blademargins are entire, with theexception ofN. mirabilisin whichthe leafblademargin is finely fimbriate, andthenonly inthelowerleaves.Otherspecies mayhavea denseindumentumbelowthemargin.Therelativenumbers, distribution and dominanceofthe longitudinalandpennatenervesis usually characteristicofthe species. Pitchersrange fromalmostglobose orurceolate,to cylindrical, and attheoppo- site extreme to narrowly or broadly infundibulate.Theedge ofthepitcher mouth bears afinelyribbed structure- theperistome. Intransversesection theperistome is moreor less T-shaped, withthearms oftheTcurving downwardsand inwards.On theinneredge oftheperistome thecorrugations mayend in sharply pointed teeth, andbetweeneachoftheseteethlies anectar gland. Theperistome ofsomespecies is much reduced,especially soin theupperpitchers. Inothers thecorrugations ofthe peristome havebecomevastly enlarged and widely spaced, giving theappearanceof flatplates or hooks.Ina few species theinner marginoftheperistome has become elaboratedinto amore complex structure (N. edwardsiana, N. rajah andN. villosa). Theshape and glandulation ofthelidcanbeofgreatdiagnostic value. Somespe- cieshaveoneormoreappendages on themidlineofthelowersurfaceofthelid.The lid glands range in size from less than0.1 mmto 3 mm across, and maybe either shallow depressions or have anarrow rim ora prominent swollenlip around their margin. Nepenthes are dioecious, and only begin flowering once upperpitchers arepro- duced.Theinflorescencerangesfromaraceme of 1-or2-floweredpartial peduncles, to apanicle of3-10-floweredpartial peduncles. Thefemaleinflorescenceis usually shorterandsomewhatmorerobustthanthemale,andinthepaniculate species thepar- tialpeduncles bearsomewhatfewerflowers.Towards theapexofthe inflorescence inall species, thepartial peduncles areinvariably fewer-flowered, andmanyspecies, eventhepaniculate ones, mayhavevariantswithwholly 1-floweredpartial peduncles (racemes). Sometimesinflorescenceswithpartial peduncles entirely 1-and2-flower- edoccur onthesameplant(N. spectabilis). Filiformbracts arepresenton thepartial peduncles ofmanyspecies,butthisfeaturecan again bevariablebetweenpopulations insomespecies, butinotherspecies provides animportant character. 6 BLUMEA—Vol. 42, No. 1, 1997 PHYLOGENETIC CONSIDERATIONS ThenaturalrelationsofNepenthaceaehavebeenmuchcontestedinthepast. Biochem- istryandrbcL genesequencedata(Williams etal., 1994)suggestthatNepenthes has arelationship toPolygonaceae/Plumbaginaceae ontheonehand,andwithDrosera- ceaeontheother. Genesequence workis currently beingconductedattheNewYork BotanicGarden. Allspecies ofNepenthes investigated to date havea chromosomenumberofn= 40; thisis concordantwiththeapparentlack ofbreeding barriers tointerspecific hy- bridisation(Lowrey, 1991).Astudy ofthirteenenzyme systemsrevealedtypical iso- zymeranges fordiploid seedplants, and no duplicated loci were found, which does not supportapolyploid origin forthefamily (Lowrey, 1991). Danser(1928)proposed six groupings ofspecies,each inturn sub-divided into smallergroups. Whilstthereis littleevidenceto supportsomeofhis groupings, oth- ers continuetoappearwholly natural. Comparatively few species havepaniculate inflorescences, and theseappearto form two distinctlineages, with N. madagascariensis, N. masoalensis, N. pervillei andN. distillatoria, forming one groupinthewesternrange ofthegenus,andN. to- moriana,N. danseri,N. neoguineensis andN. paniculata forming asecond eastern group.The remaining two species, N. ampullaria andN. bicalcarata, shownopar- ticularmorphological affinitieswitheitherof thesegroupsor with any otherspecies forthat matter. Nepenthes adnata,N. murudensis, N. reinwardtiana, N. tentaculataandN. hamata all showaffinitiesintheirleaves (adnate tothestem)andpitchers (narrowperistome, flaredorrhomboidalmouth). The last two species appearto beparticularly closely related.Thelittleknown N. campanulata may alsoberelatedtothis group. InSumatramanyofthemontane species appeartosharea commonorigin, species delimitationsareoftenconfinedto oneortwo correlatedcharacters.Nepenthes aristolochioides, N. bongso, N. densifloraandN. ovata shareinfundibuliformpitchers, whileN. diatas, N. singalana andN. spathulata share ventricose-tubularpitchers. Nepenthes gymnamphora ofJavaandN. pectinata ofSumatra are a further pairof species whichappeartobe relatedtothis grouping. Incontrast thespecies fromBor- neoappeartoincluderepresentatives fromdiverseevolutionary lineages. ThePeninsularMalaysian montane species N. gracillima, N. macfarlanei, N. ramispina, and N. sanguinea appearrelatedtothoseofSumatrabutpose certainprob- lems.Whilstreadily distinguishable intheirtypical forms, muchherbariummaterial and somewildpopulations can only be distinguished with difficulty andnot without somereservation(Danser, 1928). Danser's Regiae grouping remainsa good morphological unit,including N. maxi- maandits supposed relatives;N. borneensis, N. boschiana, N. burbidgeae, N. clipeata,N. eymae,N.fusca, N. klossii, N. maxima, N. pilosa, N. rajah, N. stenophylla, N.truncata,andN. veitchii. Besides thesegroups, the species eitherappearisolated, or fall into morphologically similar pairs or threesomes, someofwhich suggest geographical vicariant origins: N. dubiaand N. inermis; N. gymnamphora andN.pectinata’, N. lamiiand N. vieillardii’,N. burkeiandN. ventricosa; N. ephippiata andN. lowii;N. mapulu- M.Jebb& M.Cheek: Skeletal revision ofNepenthes 7 ensisandN.northiana;N. edwardsiana, N.macrophylla andN. villosa; N. hirsuta, N. hispidaandN. macrovulgaris. BIOGEOGRAPHY Ofthe82species ofNepenthes, only 10species havedistributionsgreaterthan asingle island or smallgroupofislands. Of these, N. mirabilishas the largest range, encompassing the range ofallbutsix otherspecies. Danserwas struckby theiso- lationofthewestern species inMadagascar, theSeychelles, SriLankaandtheKhasia Hills,and suggested a Gondwanicoriginofthegenusto account fortheirdistribu- tion, witharelatively recentexpansion intotheMalesiaregion (Danser, 1928). BesidesN. mirabilis, twootherspecies have amoderately broaddistribution; N. ampullaria, foundfromSumatratoNew Guinea, but mysteriously absentfromSula- wesi and the Moluccas; and N. maxima from Sulawesiand theMoluccas to New Guinea. Nepenthes alata is found throughoutthe Philippine islands. Four species havea distinctSunda-shelfdistribution,being foundinSumatra,PeninsularMalaysia and Borneo(N. albomarginata, N. gracilis, N. reinwardtiana, andN. rafflesiana). Nepenthes tentaculatais foundin BorneoandSulawesi,andN. danseriis found in HalmaheraandWaigeo. Species richness appearstobe wellcorrelatedto thehistorically ever-wet cores recognised in theregion (Van Steenis, 1979:fig.4). Thewell leachedvolcanicsoils ofthecentral Sumatranmountainssupporta greatdiversityofspecies (25, ofwhich 17are endemic),andtheseappeartostemfromrelativelyfewancestral groups,forming a swarmofsometimeshardto distinguish species. Borneo,by comparison, has by fartherichest Nepenthes flora(31 species, ofwhich25 areendemic), andthema- jorityofthesetaxaare morphologically quiteisolatedfromoneanother.Thediversity ofsoiltypes maybeanimportant factorintheevolutionofthegenusinBorneo(ultrabasic, limestoneandsandstonesoils). Therelatively depauperate Nepenthes floraofthenorthernPhilippines, Sulawesi, Moluccas, theeastern SundaIslands andtheeastern endofNewGuinea isprobably explained by thepresence ofseasonal droughts intheseregions, as well as thepres- enceofactive volcanoesintherecentpast,andtheconsequently rich soilswhich do not favourNepenthes. NOTES ON IDENTIFYING SPECIES Anumberofspecies haveunique spot characters, whichprovideinstantrecognition. Floweringmaterialmaybeofbenefitinidentifying thepaniculate species (10),but it isofless use forthemajorityofspecies. Thebranching ofthepartial peduncles and presenceofabractcanbe quitevariablewithinaspecies. Thepresence ofangularstems,often withacuteridges, andtheleafinsertionon thestem (whetherpetiolate or sessileand combinedwith amplexicaul or decurrent bases) provide important characters. Leafshape maybesomewhatvariable,butthe numberand distributionofthelongitudinal veinsis usuallycharacteristicofaspecies. Anumberofspecies havepeltate leaftips (N. campanulata, N. clipeata, N. mapulu- 8 BLUMEA —Vol. 42, No. 1, 1997 ensis, N. northianaandN. rajah), although othersare somewhatvariableinthis re- gard,andmayhavesub-peltate tips totheleaves(N. bongso andN. eustachya). Pitchershape is not areliablemeansofdetermining identity ofaspecimen withthe exception ofafewspecies. The developmentofventralwings onthepitcher can like- wisebe variable.The peristomeprovides anumberofusefulcharacters, especially in itssizeandshape, andmostimportantly thenature ofitsinnermargin,whetherentire or toothed.Thedistributionandsize ofglands underthelid can be diagnostic ofa species. Theindumentumcanprovide important characters,by itstype,densityandcolour. MATERIALS AND METHODS A numberofimportant collectionshave not been availableforthisstudy, and we havenot been ableto seethecollectionsatthefollowing herbaria:B(Warburg), CGE (T.Lobb), FI(Beccari), PENN(Macfarlane), PNH(Philippine material), SAN(re- cent Sabahmaterial)andtheherbariumoftheNippon DentalCollege, Fujimi, Tokyo (Shigeo Kuratacollections). Many othercollectionsremaininprivate hands,andthe holotypes ofanumberofrecently published species (N. eymae,N. glabrata andN. hamata) havenotbeendeposited inthe herbariastatedintheirprotologues. For 12 recently describedIndonesiantaxa,notypehasbeendeposited atthe nationalherbar- ium(Bogor). Manyoftheearly collectionsfromAsia,fromwhichspecies were described,were not identifiedbynumbersorexactdatesorlocalities,andinterpretationofseveral types (e.g., thosecollected by Burbidge, FobbandFow) is complicated by thislack ofin- formation.Ininterpreting thesetypeswehavetakencare toensure thatthelocalities and description arecompatible withtheoriginal protologues, aswellas allotherclues relating to handwriting or previous interpretations. Several species were described from cultivatedmaterialaloneand theprovenanceofthese can be very imprecise. Fivenames areregarded as too imperfectly knowntobeincludedasrecognised species, andtheseareplaced inasectiononLittleKnownTaxa.Threenames arereject- ed; theseareeitherbasedon mixedtypesor derivefromhorticulturalsourcesofun- knownprovenance. Thefollowing herbariahave been consulted: BK, BO,DBN, K,KEP, KLU,L, LAE, OXF,P, SAR, SING,SINU, TCD, UPNG,and W. GEOGRAPHICAL KEYS TO THE MALESIAN SPECIES OFNEPENTHES Key to the Sumatranspecies la. Lidwith acurved, hook-likeprocess nearthebase 57.N. ovata b. Lidwithoutacurved,hook-likeprocess nearthebase, atmostaswollenlump 2 2a. Pitchermouthlateral, upperpitchers utriculiform 7.N. aristolochioides b. Pitchermouthapical, pitchers urceolate, tubularor infundibuliform 3 3a. Pitcherwithaprominentrimofwhitehairsimmediately belowperistome 3. N.albomarginata b. Withoutarimofwhitehairs belowtheperistome 4 M.Jebb& M.Cheek: Skeletal revision ofNepenthes 9 4a. Lidnarrow, atleastfourtimesas long as broad 5 b. Lidbroad, less thanthree timesaslong asbroad 7 5a. Pitcherglobose, lidwithoutglands below 4. N.ampullaria b. Pitcherstrikingly infundibulate, widening greatly tothemouth, lidwithglands 6 6a. Peristomelacking 35.N. inermis b. Peristomepresent 21.N. dubia 7a. Stemtriangular andleafbasesdecurrenttotwo ofthese 8 b. Stemroundedor angular, but thenleafbases not decurrent 9 8a. Peristomeinner margin withoutteeth;lidwith numerousminute glands 67. N.reinwardtiana b. Peristomeinnermargin withteeth; lidwith<50 large,rimmedglands 28. N. gracilis 9a. Marginoflowerleavesfimbriate 51. N. mirabilis b. Marginoflowerleavesentire 10 10a. Leafbases decurrentoradnate 11 b. Leafbase amplexicaul or sessile 17 11a. Leafbases not narrowedtoapetiole 12 b. Leaves petiolate 14 12a. Lidglandsminute(<0.15mm),numerous, throughout undersideoflid 1. N.adnata b. Lid glands large(0.3-0.5 mm),few (< 50), nearbase andmidline,or throughout 13 13a. Lidovate;glands nearbaseandalongmidlineonly 60. N.pectinata b. Lidelliptic; glands throughout 80.N.x trichocarpa 14a. Lidoblong-elliptic, apexnotched 34. N.x hookeriana b. Lidroundedorovate,apexrounded 15 15a. Leafbaselong decurrentinto2ridgesrunning almosttonextaxil 74. N.sumatrana b. Leafbase shortly decurrent,attenuate wings to2cm longatmost 16 16a. Lidglands numerous, small (<0.3 mm),throughout centre oflid 72.N.spectabilis b. Lidglands few,large(0.3-0.5 mm), nearmidlineandbase only 60.N. pectinata 17a. Peristomeextendedintoaflattenedneck; lidglandsabsentfromcentreofthelid 64. N. rafflesiana b. Peristomenot extendedintoaneck; glands less numeroustowards margin . 18 18a. Stemsrounded, slender(<3 mm);leaveslessthan 13x2 cm 19 b. Stemsroundedorangular(> 3 mm);leaveslargerthan 13x2cm 20 19a. Axils with conspicuous downyindumentum 77.N.tobaica b. Axils glabrous 50. N.mikei 20a. Lidoblong-elliptic; apextruncate ornotched 34.N. x hookeriana b. Lidroundedtoovate;apexnot notched 21 21a. Innermargin ofperistomeentireor withvery shortteeth <0.3mmlong... 22 b. Inner marginofperistome withprominentteeth, 0.4-10mmlong 24 10 BLUMEA—Vol. 42,No. 1, 1997 22a. Stem angular 68.N.rhombicaulis b. Stemrounded 23 23a. Leafpetiolate 24.N.eustachya b. Leafsessile 50.N.mikei 24a. Stemangular 25 b. Stemrounded 26 25a. Peristomeflattenedtowardsneck andmuchbroaderthere . 71.N.spathulata b. Peristomeofmoreor less even widththroughout 70.N.singalana 26a. Leafbladesoflowerpitchers oftenvery small(<8x2 cm), upperleavesusual- ly muchlarger(20-25 x5 cm), lanceolate,base tapering ... 60.N.pectinata b. Leafbladesoflowerpitchers larger(>10x2 cm),upperleaves similarin size (16x4 cm),obovate, base parallel-sided 27 27a. Upperpitchers distinctly ventricosebelow, tubularabove 28 b. Upper pitchersinfundibuliformor ellipsoid throughout 29 28a. Peristomerigid, somewhatwoody 19.N. diatas b. Peristomepaperyin texture 7. N.singalana 29a. Pitcherarising abruptly in ashortcurvefromthetendriltip 18.N. densiflora b. Pitcherarising verygradually, andinabroadcurvefromthetendriltip 10.N. bongso Key to the Peninsular Malaysian species la. Leafbase distinctlypetiolate 2 b. Leafbase tapering, decurrentoramplexicaul,but neverpetiolate 5 2a. Lid narrow; lacking glands 4.N.ampullaria b. Lidelliptic; withatleastsome glands 3 3a. Lowerleafmargins fimbriate 51.N.mirabilis b. Lowerleafmargins not fimbriate 4 4a. Lid withmanyglands confinedtoedges 64.N. rafflesiana b. Lidwithfew,scattered, prominently rimmedglands 6 5a. Leafbase petiolate;lidovate,apexrounded 80. N.x trichocarpa b. Leafbaseattenuate,not petiolate; lidapexnotched .... 34.N.x hookeriana 6a. Leafbase decurrenttostem 7 b. Leafbaseamplexicaul, butnot decurrent 8 7a. Withawhitecollarbelowtheperistome 3.N.albomarginata b. Lacking awhitecollarbelow theperistome 28.N. gracilis 8a. Lidrounded, cordateatbase,peristomenarrow, rounded, stemrounded .. 9 b. Lidovate,truncate atbase, peristome broader,irregular, stemangular 10 .... 9a. Pitcherspurbranched; lidglands numerous, small (0.2-0.3 mm) 66.N.ramispina b. Pitcherspursimple; lidglands few, large(0.4-0.5 mm) . . 29.N. gracillima 10a. Stem sharply 3-angled,peristome scarcely toothedwithin,lid withouthairsbe- low 69.N.sanguinea b. Stem perceptibly 3-angled, peristome teethlarge nearlid, lid withhairsbelow 42.N. macfarlanei