A skeletal revision of Nepenthes (Nepenthaceae)

106 Pages·1997·8.8 MB·English

by  Jebb, Matthew

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 descrip-
tions 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 culti-
vars 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 spe-
cies. 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 col-
lectors.
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. vil-
losa), 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) distin-
guished 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),al-
though 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 aris-
tolochioides, 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. ra-
mispina, 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. clipe-
ata,N. eymae,N.fusca, N. klossii, N. maxima, N. pilosa, N. rajah, N. stenophyl-
la, N.truncata,andN. veitchii.
Besides thesegroups, the species eitherappearisolated, or fall into morphologi-
cally 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 asin-
gle 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,form-
ing a swarmofsometimeshardto distinguish species. Borneo,by comparison, has
by fartherichest Nepenthes flora(31 species, ofwhich25 areendemic), andthema-
jorityofthesetaxaare morphologically quiteisolatedfromoneanother.Thediversity
ofsoiltypes maybeanimportant factorintheevolutionofthegenusinBorneo(ultra-
basic, 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 spe-
cies, 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 through-
out 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