Two new Orchidantha species (Lowiaceae) from Borneo · 1994 at Matang, Sarawak, Borneo, flowering...
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Blumea 62, 2017: 157–162 ISSN (Online) 2212-1676 www.ingentaconnect.com/content/nhn/blumea https://doi.org/10.3767/blumea.2017.62.02.08 RESEARCH ARTICLE INTRODUCTION Lowiaceae (Zingiberales), with a single genus Orchidantha N.E.Br., is a small family of about 21 species restricted to Asia. A more detailed general introduction to Lowiaceae was given in Trần & Leong-Škorničková 2010. Recent work on Lowiaceae has uncovered several new taxa from continental Asia (Trần & Leong-Škorničková 2010, Leong-Škorničková 2014, Leong- Škorničková et al. 2014, Zou et al. 2017) as well as one new species from Borneo (Syauqina et al. 2016). Eight species (and one variety) of the family Lowiaceae are found north of the Isthmus of Kra throughout the Indochinese floristic region and into southernmost China. Five different species occur on the Malay Peninsula and eight species are currently known to be endemic in Borneo. Orchidantha borneensis N.E.Br., the type species of the ge- nus, was the very first Orchidantha described (Brown 1886). The Compagnie Continentale d’Horticulture, Ghent, Belgium, introduced a live plant from Borneo to Europe without precise information of the locality of origin. The type specimen made from this cultivated plant, however, is well-preserved and the description is sufficiently detailed to establish that O. borneen- sis is a small species with light-coloured free and spreading sepals and a dark purple labellum and petals. Unfortunately, Larsen (1998) confused the understanding of the morphology of O. borneensis when he included a photograph by Josef Bogner. This photograph is of a cultivated plant, originally collected in 1994 at Matang, Sarawak, Borneo, flowering at Munich Botani- cal Garden in 1997 (acc. no. 94/1211). We studied pressed her- barium material of this plant (Bogner 2146, AAU (including four additional photographs), M). Due to the larger size of the flowers with white petals and a labellum with pale yellow apex, we have to conclude that this material does not match the type and origi- nal description of O. borneensis. Instead, Bogner’s collection is very similar, if not conspecific, with the recently described O. ranchanensis Syauqina & Meekiong, also from Sarawak. New collections from Matang at the eastern side of Kubah NP (where Bogner collected 94/1211 between the national park headquarters and the Red Bridge, Bogner pers. comm.), and elsewhere in Sarawak are needed to completely understand the morphological variation and distribution of O. ranchanensis as well as establish the likely origin of O. borneensis. Seven species of Orchidantha were subsequently described from Borneo: Larsen (1993), Nagamasu & Sakai (1999), Peder- sen (2001), Syauqina et al. (2016). Most of these are adequately described and illustrated, making identification of any new taxa uncomplicated and all are well localised. Two interesting Orchidantha species, first collected by ADP during fieldwork in Sarawak in 2003, are described and illustrated below as O. micrantha and O. megalantha, respectively. This brings the total number of Bornean species to ten with one species known from Brunei, four species each from Sabah and Sarawak and, as mentioned above, O. borneensis, unlocalised. The descrip- tions of the vegetative characters are based on living plants and dry herbarium specimens, measurements of all flower parts were made from herbarium material preserved in spirit. The style of description follows recent works of Leong-Škorničková cited above, with general plant descriptive terminology follow- ing Beentje (2016). 1. Orchidantha micrantha Škorničk. & A.D.Poulsen, sp. nov. — Fig. 1, 2 Similar to O. borneensis in the small habit and dark purple petals and labellum but differs in the overlapping lateral sepals supporting the labellum from below while the dorsal sepal arches above it (resulting in claw-like appearance of the flower vs sepals spreading), petals with irregularly serrate margin at apex (vs ± entire) and the curved labellum with prominently undulate margin (vs labellum more or less flat without undulate margin). — Type: A.D. Poulsen, H.B. Mathisen, Vilma B. & Jinaidi L. 2943 (holo SAR; iso E, SING), Malaysia, Sarawak, trail between Kubah National Park and Matang Wildlife Centre, N1°36ʹ46.14ʺ E110°10ʹ6.7ʺ, 50 m elevation, 19 Feb. 2014, flowering. Etymology. The epithet refers to the small flowers relative to other species of the genus. Clump-forming herb, up to 0.8 m tall, 7–14 leaves per shoot; juvenile plants as well as adult plants with distinctly petiolate Two new Orchidantha species (Lowiaceae) from Borneo A.D. Poulsen 1 , J. Leong-Škorničková 2 1 Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh EH3 5LR, Scotland; corresponding author e-mail: [email protected]. 2 The Herbarium, Singapore Botanic Gardens, National Parks Board, 1 Cluny Road, Singapore 259569; e-mail: [email protected]. Key words Kubah National Park Kuching Malaysia Matang Mulu National Park Orchidantha borneensis Orchidantha holttumii Sarawak vulnerable Zingiberales Abstract Two new Orchidantha species discovered in Sarawak, O. micrantha and O. megalantha, are described and illustrated. They may well represent the species with the smallest and the largest flowers currently known in the genus and certainly from Borneo. With its small flowers, O. micrantha is similar to O. borneensis to which it is compared. The large-flowered O. megalantha is compared to the morphologically closest species, O. holttumii, from nearby Brunei. The conservation status of both new species is assessed and a key is provided to all Bornean species. Published on 26 September 2017
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© 2017 Naturalis Biodiversity Center
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Blumea 62, 2017: 157–162 ISSN(Online)2212-1676www.ingentaconnect.com/content/nhn/blumea https://doi.org/10.3767/blumea.2017.62.02.08RESEARCH ARTICLE
INTRODUCTION
Lowiaceae (Zingiberales),with a single genusOrchidantha N.E.Br.,isasmallfamilyofabout21speciesrestrictedtoAsia.A more detailed general introduction to Lowiaceae was given in Trần&Leong-Škorničková2010.RecentworkonLowiaceae hasuncoveredseveralnewtaxafromcontinentalAsia(Trần&Leong-Škorničková2010,Leong-Škorničková2014,Leong-Škorničkováetal.2014,Zouetal.2017)aswellasonenewspecies fromBorneo (Syauqina et al. 2016).Eight species(andonevariety)ofthefamilyLowiaceae are found north of the Isthmus of Kra throughout the Indochinese floristic region andintosouthernmostChina.Fivedifferentspeciesoccuronthe Malay Peninsula and eight species are currently known to beendemicinBorneo.Orchidantha borneensis N.E.Br., thetypespeciesof thege-nus, wastheveryfirstOrchidanthadescribed(Brown1886).TheCompagnieContinentaled’Horticulture,Ghent,Belgium,introducedaliveplantfromBorneotoEuropewithoutpreciseinformationofthelocalityoforigin.Thetypespecimenmadefrom this cultivated plant, however, is well-preserved and the descriptionissufficientlydetailedtoestablishthatO. borneen-sis is a small species with light-coloured free and spreading sepalsandadarkpurplelabellumandpetals.Unfortunately,Larsen(1998)confusedtheunderstandingofthemorphologyof O. borneensiswhenheincludedaphotographbyJosefBogner.This photograph is of a cultivated plant, originally collected in 1994atMatang,Sarawak,Borneo,floweringatMunichBotani-calGardenin1997(acc.no.94/1211).Westudiedpressedher-bariummaterialofthisplant(Bogner 2146,AAU(includingfouradditionalphotographs),M).Duetothelargersizeoftheflowerswith white petals and a labellum with pale yellow apex, we have to conclude that this material does not match the type and origi-nal description of O. borneensis.Instead,Bogner’scollectionisverysimilar, ifnotconspecific,withtherecentlydescribedO. ranchanensisSyauqina&Meekiong,alsofromSarawak.
New collections from Matang at the eastern side of Kubah NP (whereBognercollected94/1211betweenthenationalpark headquartersandtheRedBridge,Bognerpers.comm.),and elsewhere in Sarawak are needed to completely understand the morphological variation and distribution of O. ranchanensis as well as establish the likely origin of O. borneensis.Seven species of OrchidanthaweresubsequentlydescribedfromBorneo:Larsen(1993),Nagamasu&Sakai(1999),Peder- sen(2001),Syauqinaetal.(2016).Mostoftheseareadequatelydescribed and illustrated,making identification of any newtaxauncomplicatedandallarewelllocalised.TwointerestingOrchidanthaspecies,firstcollectedbyADPduringfieldworkinSarawak in 2003, aredescribedand illustratedbelowas O. micrantha and O. megalantha,respectively.Thisbringsthetotal number of Bornean species to ten with one species known from Brunei, four species each from Sabah and Sarawak and, as mentioned above, O. borneensis,unlocalised.Thedescrip-tions of the vegetative characters are based on li ving plants and dry herbarium specimens, measurements of all flower parts weremadefromherbariummaterialpreserved inspirit.ThestyleofdescriptionfollowsrecentworksofLeong-Škorničkovácited above, with general plant descriptive terminology follow-ingBeentje(2016).
1. Orchidantha micranthaŠkorničk.&A.D.Poulsen,sp. nov. —Fig.1,2
Similar to O. borneensis in the small habit and dark purple petals and labellum but differs in the overlapping lateral sepals supporting the labellum from below whilethedorsalsepalarchesaboveit(resultinginclaw-likeappearanceoftheflowervssepalsspreading),petalswithirregularlyserratemarginatapex(vs±entire)andthecurvedlabellumwithprominentlyundulatemargin(vslabellummoreorlessflatwithoutundulatemargin).—Type:A.D. Poulsen, H.B. Mathisen, Vilma B. & Jinaidi L. 2943(holoSAR;isoE,SING),Malaysia,Sarawak,trailbetweenKubahNationalParkandMatangWildlifeCentre,N1°36ʹ46.14ʺE110°10ʹ6.7ʺ,50melevation,19Feb.2014,flowering.
Etymology.Theepithetreferstothesmallflowersrelativetootherspeciesofthegenus.
Clump-formingherb,upto0.8mtall,7–14leavespershoot;juvenile plants as well as adult plants with distinctly petiolate
Two new Orchidantha species (Lowiaceae) from BorneoA.D.Poulsen1,J.Leong-Škorničková 2
1 RoyalBotanicGardenEdinburgh,20AInverleithRow,EdinburghEH35LR,Scotland;correspondingauthore-mail:[email protected].
2 TheHerbarium,SingaporeBotanicGardens,NationalParksBoard,1ClunyRoad,Singapore259569;e-mail:[email protected].
Key words
Kubah National ParkKuchingMalaysiaMatangMulu National ParkOrchidantha borneensisOrchidantha holttumiiSarawakvulnerableZingiberales
Abstract Two new Orchidantha species discovered in Sarawak, O. micrantha and O. megalantha, are described andillustrated.TheymaywellrepresentthespecieswiththesmallestandthelargestflowerscurrentlyknowninthegenusandcertainlyfromBorneo.Withitssmallflowers,O. micrantha is similar to O. borneensis to which it is compared.Thelarge-floweredO. megalantha is compared to the morphologically closest species, O. holttumii, from nearbyBrunei.TheconservationstatusofbothnewspeciesisassessedandakeyisprovidedtoallBorneanspecies.
Published on 26 September 2017
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Fig. 1 Orchidantha micranthaŠkorničk.&A.D.Poulsen.a.Habit(inset:openedemptycapsule);b.habit;c.inflorescence;d–e.detailsofflower(a,c:Poulsen et al. 2029;b,d–e:Poulsen et al. 2943).—Photos:AxelDalbergPoulsen.
159A.D.Poulsen&J.Leong-Škorničková : Two new Orchidantha species from Borneo
leaves; leaves to c. 1.2m long, petiole 20–65 cm, laminaunequal, narrowly elliptic, 23–55× 7–11 cm, base asym-metrical, obtuse toattenuate,apexattenuate. Inflorescence on a slender, branched, pale to cream-coloured, burrowing stemwithprominentbractsand/ortheirscars;prophyll trian-gular,two-keeled,c.8mmlong;second bract c.16mmlong,shortlysharplycuspidate; third bractc.22mm long,shortlysharplycuspidate;floral bract appearing above the soil or with the proximal part subterranean, pale green, sometimes tinged ±purpletowardsapex,35mmlong.Flowers emitting a pungent smell;pedicelc.7mmlong;ovary extensionc.27mmlong,whitetopalegreenish;sepals greenish white, narrowly elliptic, shortlysharplycuspidateatapex,glabrous,entire;dorsal sepal c.23mmlong,c.7mmwide;lateral sepals overlapping, often crossingandsupportingthelabellum,c.25mmlong,6–7mmwide;lateral petals overlapping at base covering stamens and style,darkpurple,elliptic,8–8.5mmlong,c.3mmwide,outermargin undulate at the distal half, irregularly serrate at apex with aprominentmucroto1mmlong;labellum ovate to elliptic with raisedmidrib(1–1.5mmwide),c.23mmlong(incl.the1mm
longacuminatetip),c.10mmwide,darkpurplethroughout,withtheverytipfadingtoadirtyorangein2nddayflowers;sides reticulate with vertical lines much more pronounced, marginprominentlyundulatedistally.Stamensc.5mmlong;filaments1.5–2mmlong;anther thecaeintrorse,3–3.5mmlong, longitudinally dehiscent throughout their length.Style c.3.5mmlong;stigma 3.5mmlong,deeply3-lobed,condupli-cate,marginirregularlydenticulate,medianlobec.2mmlong;lateral lobesc.1.5mmlong;viscidiumbluntlyheart-shapedandextendingfromthebasetoabout1/3ofthelaterallobe(pronouncedinsideview);sideoftheheart-shape1.5–2mmlong.Fruita3-locular,loculicidalcapsule,ovoid,narrowingtoabeakatapex,bluntlytrigonous,c.40mmlong(incl.the5–8mmlongbeak),c.15mmdiam(youngfruit27×10mm),darkviolet to almost black externally, straw-coloured with pink-purple shadesinternally,dehiscinglongitudinally;seeds(fromnotfullymaturefruit)c.6×4mm,glabrous,ampulliformwithaseedcoatswellingatbaseforminganeckthatbears2–4arilthreads,arilthreadsupto8–11mmlong,curled,glabrous. Distribution—Sofarknownonlyfromtwolocationsonthewestern side of Kubah National Park near Kuching, distanced withinonekilometrefromeachother. Habitat&Ecology—Kerangasforest,flatareanearriver(Poulsen et al. 2029)andlowdipterocarpforest,onsandysoil(Poulsen et al. 2943).FloweringrecordedinFebruaryandJuly.
Other specimen examined.Malaysia, Sarawak,SungaiRayu,N1°37ʹE110°10ʹ,50melevation,2July2003,floweringandfruiting,A.D. Poulsen, Effendy Supot, Jais & Jugah 2029(AAU,E,L,SAR,SarawakBiodiversityCentre).
Conservation status — Orchidantha micrantha is reported from two populations each of several individuals a few hundred metres apart at the same general habitat within a protected area withnoperceivedthreats.Asthenumberofmatureindividualsis<1000,itmaybeconsidered‘Vulnerable’(VU)D1(IUCNStandardsandPetitionsSubcommittee2017).
Notes—1.InBorneo,thisspeciesismostsimilartoO. bor- neensisduetoitssmallhabit,andsimilarityinsizeandcolour-ing of the flower although the differences in flower structure as outlined in the diagnosis makes the two species unmistake-able.Furtherdifferencesbetweenthetwospecies,basedon
Fig. 3 Orchidantha borneensis N.E.Br.a.Flower;b.detailofstigma,stamensandpetal(alloftheholotypeatK[K000292159]reproducedwithpermissionoftheDirectorandBoardofTrustees,RoyalBotanicGardens,Kew).—Photos:JanaLeong-Škorničková.
Fig. 2 Orchidantha micranthaŠkorničk.&A.D.Poulsen.a.Petals,stamensandstylewithstigma(ventralview);b.petal;c–e.detailofstigmainventral,dorsalandlateralview(all:Poulsen et al. 2943,pickledmaterial).—DrawingbyAxelDalbergPoulsen.
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Fig. 4 Orchidantha megalanthaŠkorničk.&A.D.Poulsen.a.HabitandBiogoMutangholdingafloweratthetypelocality;b.oldflower(frontview);c.freshflower(obliqueview);d.detailofbaseofthelabellum,petalsandstigma;e.oldflower(sideview;notethereflexeddorsalsepal);f.detailoflateralsepalswithcrossedapicessupportingthelabellum(all:Poulsen et al. 2073).—Photos:AxelDalbergPoulsen.
161A.D.Poulsen&J.Leong-Škorničková : Two new Orchidantha species from Borneo
examination of the type specimen of O. borneensis which has twowell-preservedflowers(Fig.3)canbeoutlinedasfollows:Orchidantha micrantha has petals where the margin at apex is irregularlyserrate,anovatetoellipticlabellumc.23× 10 mm with a prominent midrib throughout the entire length, and the margin to the stigma is irregularly denticulate whereas O. borne-ensis in comparison has petals with an entire margin, a linear c.21×3.5mmlabellumwherethemidribisonlyprominentinthelowerhalf,andthestigmamarginlaciniate.Therecentlydescribed O. ranchanensis from Sarawak also has spreading sepals and is therefore easy to distinguish from O. micrantha. 2.IncontinentalAsia,themorphologicallymostsimilarspe-cies would be O. stercoreaH.Đ.Trần&Škorničk.(colourfigureinTrần&Leong-Škorničková2010)andO. laotica K.Larsen(colourfigureinZouetal.2017).Bothspeciesaresmallandhave flowers with a dark labellum in a claw-like arrangement ofpale-colouredsepals.Neitherofthesespecieshasanun-dulate labellummargin. Inaddition,O. laotica has lamellate yellow stripes at the base of the labellum, while the flowers of O. stercorea are larger than those of O. micrantha.
2. Orchidantha megalanthaŠkorničk.&A.D.Poulsen,sp. nov. —Fig.4,5
Similar to O. holttumii in overall habit, the petiolate leaves, and the claw-like arrangement of the petals, but differing in the larger flowers with slightly unequalsepals(vsequal),dorsalsepal14–15×4–4.1cm,lateralsepals15–16 ×3.7–3.9cm(vsc.9×2cm),labellum12.5–13.5×c.4cm(vs7× 2cm)andpurplestigma(vswhite).—Type:A.D. Poulsen & Biogo Mutang 2073(holoSAR;isoAAU,SarawakBiodiversityCentre,SING),Malaysia,Sarawak,MuluNP,shortcut trailbetweenthePenanvillageandGunungMulu,N4°02ʹE114°49ʹ,30melevation,17July2003,flowering.
Etymology.Theepithetreferstothelargeflowersrelativetootherspeciesofthegenus.
Robustclump-formingherb,upto1mtall,c.14–15leavespershoot;juvenileplantsaswellasadultplantswithdistinctlypeti-olateleaves;leaves to1.3mlong(includingpetiole),petioleupto55cm;laminaunequal,elliptic,to75×15.5cm,baseasym-metrical,attenuate,apexnarrowlyattenuate.Inflorescence on a slender, branched, pale to cream-coloured, burrowing stem with prominentbractsand/ortheirscars;prophyll triangular, two-keeled,22–23mmlong,13–14mmwideatbase;second bract 30–42mmlong,c.15mmwideatbase,shortlycuspidate;third bract45–60mmlong,c.20mmwideatbase,shortlycuspidate;
floral bract burrowed in the soil at base, apex appearing above the soil, green with a rich rusty-red tinge apically when exposed aboveground,90–130mmlong,c.32mmwide.Flower smell notrecorded;pedicelc.30mmlong;ovary extensionc.100mm long,cream-whiteatbasetogreen-yellowapically;sepals yel-low-green(dorsalsepalwithaslightrusty-redtingeparticularlytowardsthesides),narrowlyelliptic,cuspidate,glabrous,entire;dorsal sepal140–150mmlong,40–41mmwide(cuspc.3mm); lateral sepals overlapping, often crossing and supporting the la-bellum,150–160mmlong,37–39mmwide,cuspidateatapices(cuspc.5–6mm);lateral petals overlapping at base covering stamens and style, dark purple, irregularly elliptic, cuspidate (cusp3–4mm,recurved),40–42mmlong,11–12mmwide,outermarginundulateatthedistalhalf; labellum elliptic with stronglyraisedmidrib(c.4mmwide),125–135mmlong(includ-inga5–10mmlongacuminatetip),c.40mmwide,darkpurplethroughout but slightly fading towards apex, sides strongly re-ticulate with vertical lines more pronounced, sides and margins oflabellumundulateandinvolutedistally.Stamensc.25mmlong;filaments7–8mmlong,2mmbroad,cream-whitewithslight purple tinge;anther thecae introrse, 14–15mm long,longitudinally dehiscent throughout the length.Style cream-white,c.21mmlong;stigmac.17mmlong,deeply3-lobed,dorsal surface and stigma lobes tinged purple, conduplicate,
Fig. 6 Orchidantha holttumiiK.Larsen.a.Habit;b.flower(ex-situcollectionatSungaiLiang,Brunei).—Photos:MuhdAriffinAbdullahKalat(BRUN).
Fig. 5 Orchidantha megalanthaŠkorničk.&A.D.Poulsen.a.Petals,stamensandstylewithstigma(ventralview);b.petalwithtwostamensattached;c–e.detailofstigmainventral,dorsalandlateralview(all:Poulsen et al. 2073, pickledmaterial).—DrawingbyAxelDalbergPoulsen.
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margin membranous, minutely laciniate, median lobec.11mm long; lateral lobes c. 10mm long;viscidium V-shaped and extendingfromthebasetoabouthalfofthelaterallobe(pro-nouncedinsideview);sideoftheV-shapec.9mmlong. Distribution—Sofarknownonlyfromthetypelocality. Habitat&Ecology—Growingonasandyhillc.300mfromalimestonecliff.FloweringobservedinthefieldinAprilandJuly.
Conservation status — Orchidantha megalantha is reported from one population on a sandy shallow hill with several indi-vidualswithinanationalparkareawithnoperceivedthreats.As the number of mature individuals is < 1 000, it may be con-sidered‘Vulnerable’(VU)D1(IUCNStandardsandPetitionsSubcommittee2017).
Note — Orchidantha megalantha resembles O. holttumii K.Larsen(Fig.6)bytheheightnotexceeding1.5mandthepresenceofpetiolateleavesinbothyoungandadultindividuals.Theshapeoftheflowerisalsosimilar;thetwolateralsepalsoverlapping below the labellum and the dorsal sepal arching over it, resulting in claw-like appearanceof the flower.Theflower of O. megalantha is, however, twice as big as that of O. holttumii, the sepals are bright yellow-green and stigma is purple(comparedtopalegreenishsepalsandwhitestigmainO. holttumii).Sofar,allspeciesofOrchidantha are known to beveryrestrictedintheirdistribution(Sakai&Inoue1999).Thedifferenceinthesizeandcolourationoftheflowerislikelyanadaptationtoaspecificpollinator,mostlikelyadungbeetle,aspreviously reported for other species of Bornean Orchidantha (Sakai&Inoue1999,Pedersen2001).
KEY TO THE BORNEAN SPECIES OF ORCHIDANTHA
1. Lateralsepalsoverlappingandsupportingthelabellum. 21. Lateralsepalsspreading,notsupportingthelabellum. . . 72. Leavesofadultplantsclearlypetiolate . . . . . . . . . . . . . . 32. Leavesofadultplantswithoutpetiole,baseattenuate . . 63. Labellumbroadlyelliptic,shallowlyboat-shaped,darkpurple
at base, gradually changing to warm yellow towards apex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . O. quadricolor
3. Labellummoreorlessinvolutewithprominentlyraisedmidriband more or less undulate margins, plain dark purple . . . 4
4. Flowerssmall:sepalsandlabellumnotexceeding2.5cm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . O. micrantha
4. Flowerslarge:sepalsmorethan9–16cmlongandlabellum7–14cmlong . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.Sepalsc.9cmlong.Labellumc.7cmlong. . O. holttumii5.Sepals14–16cmlong.Labellum12.5–13.5cmlong . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . O. megalantha6.Sepals 73–100× 11–12mm.Petalswhitishwith purple
tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .O. sabahensis6.Sepals57–70×11–14(–18)mm.Petalsplaindarkpurple
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . O. suratii7. Labellumpurplewithyelloworwhitishapex,sometimesalso
withwhitishmidrib(Sarawak) . . . . . . . . . . . . . . . . . . . . . 87. Labellumblackishvioletordarkpurplethroughout. . . . . 98. Lamina70–120×11–15cm.Labellumpurplewithwhitish
apex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . O. inouei8. Lamina 22–40× 6–10 cm. Labellumpurplewith yellow
apex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . O. ranchanensis9.Robustplantto1.5mtall.Labellum97–117×40–45mm,
including to 7 mm long acumen . . . . . . . . . . O. grandiflora9.Smallplantc.0.3mtall.Labellumc.21×3.5mm . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . O. borneensis
AcknowledgementsSarawakBiodiversityCentre(SBC)providedpermitsfor research on Zingiberales inSarawak for the first author in 2003; theForestDepartmentinSarawakgavepermissiontoconducttheresearchin2014.HisfieldworkwaskindlysupportedbyHRHFrederik,CrownPrinceofDenmark.TheresearchofthesecondauthorwassupportedbytheNationalParksBoard,Singapore and by theCzechScienceFoundation,GAČR(GrantNo.P506/14/13541S).WeshouldalsoliketothankthekeepersoftheherbariaofAAU,E,K,KEP,M,P,SAN,SARandSINGforlettingusexamine their collections and sending material on loan, staff at SBC and ForestryResearchCentre,MuluNPandKubahNPinSarawakforlogisticandotherhelp,andMuhdAriffinAbdullahKalat(BRUN)forlettingususehis photographs of O. holttumii.AtMunichBotanicalGarden,wearegratefultoitsdirector,SusanneS.Rennerforinvitingthefirstauthoronaresearchvisit, Josef Bogner for providing locality information of his collection and usefuldiscussions,TillHägeleforcheckingaccessionsinthelivecollectiondatabaseandHajoEsserforprovidingdigitalimagesofherbariumspecimens.Fig.3isreproducedwithpermissionoftheDirectorandBoardofTrustees,RoyalBotanicGardens,Kew.
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