ree2l

Principes, S6(21, 1992, pp. 79-83

Besides the cultivated and sometimesnaturalized betel palm, Areca catechu L.,two species of the genus Areca were wttfrecently known from Peninsular Malaysia.The diminutive A. ridleyana, origirrralTyidentified as A. furcata Becc. by Ridley(1907), with its slender stems, irregularlydivided leaf-blades and short sparselybranched inflorescences bearins multista-minate flowers is easily distinguished; itoccurs sporadically from Terengganu southto Johor. The other species, A. triandraRoxb. ex Buch. Ham., is widespread,occurring elsewhere in Burma, Thailand,Indochina, Sumatra, Java and Borneo; itis highly polymorphic but easily separatedfrom other species by the presence of threerather than six stamens in the staminateflowers. In Peninsular Malaysia it is con-venient to recognize two main types withinthe complex; there is a robust clusteringtaxon, usually referred to as A. triandra,and a small single-stemmed taxon conve-niently referred ro as A. latiloba Ridley.A. latiloba is also present in Sumatra andJava and possibly in South Thailand. l.tnontana Ridley, based on a collectionmade by Burn-Murdoch from SemangkokPass, is a synonym of A. latiloba, whichdeserves further research as broad andnarrow leaflet forms have been observed.

In Sumatra, A. ridleyana is absent, butA. triandra is widespread, both robustclustering and small solitary forms occur-ring. The presence of another wild speciesof Areca in Sumatra was established whenone of us (JD) collected a small solitary

DRANSFIELD AND CHONG.KEAT: NEW SPECIES OF ARECA

A New Species of Areca fromPeninsular MalaYsia and Sumatra

JoHN DnuvsFrELD AND Lnr Cuonc-KrerRoyal Botanic Gardens, Keu, Richmond, Surrey TV/g SAE, U.K. and

215 Jalan Macalister, 1O45O Penang, Malaysia

species o{ Areca at Bohorok, Langkat inNorth Sumatra, an area with strong flo-ristic affinities with Peninsular Malaysia.This taxon was remarkable for its litter-trapping habit and tardily abscissing leaveswith inflorescences bursting through therotting leaf sheaths (Fig. 2). The inflores-cences were also striking in their thick stiffpurple rachillae.In 1977 JD collected whatwas apparenlly the same taxon growing inthe coastal mountains of north Terengganuin Peninsular Malaysia, an area rich inpalm novelties (see Dransfield L978, 1982;Mogea l9B4). A collection made by Cock-burn, also in the Terengganu hills, wasfound among the undetermined palms atKepong and collections made in EndauRompin by Wong Khoon Meng, duringthe Malayan Nature Society's Endau-Rompin Expedition, also appear to fit thissame taxon. Independently during 1990Lim Chong-Keat and his colleagues fromthe Penang Botanical Gardens under thebotanical project called Palm SearchMalaysia located fine examples in UpperPerak, and repeatedly monitored a colonyunder predation by elephants. They col-lected extensive specimens now lodged atthe Forest Research Institute Malaysia(KEP) and Kew (K).

Although there is variation betweenpopulations in Peninsular Malaysia andSumatra, there is also great variation withinpopulations and we thus consider them allto be conspecific. At the time of confirmingthe joint publication of the new species,the demise on 7 December 1990 of Tunku

r9921

Abdul Rahman Putra al-haj, the first PrimeMinister of Malaysia, gave point to ourspontaneous intent to honor him and theideals he promoted; we have named thepalm Areca tunku.

Areca tunku J. Dransf. & Lim Chong-Keat sp. nov. (Figs. l-4).

Ad sectionem Arecellam H. A. Wendl.& Drude pertinens, a ceteris speciebusSumatranis vel Malayanis Arecae petiolocarenti et rachillis crassis purpureis benedistincta; A. jugahpunya J. Dransf. et A.ahmadii J. Dransf. speciebus borneensi-bus affinis sed a A. jugahpunya inflores-centia rachillis paucioribus minoribus petalisfloris masculi non connatis et a A. ahrnadiihabitu caulescenti et inflorescentia infra-foliacea pedunculo brevi distincta. Typus:Peninsular Malaysia, Terengganu,,I.DJansf.eld et al. IDSL7B (holotypus K;isotypus KEP).

Solitary, unarmed, monoecious palm to2.5 m tall. Stem often stilt-rooted at thebase, dull green when young, becomingpale brown, 2-6 cm diam., internodes 2-3 cm, nodal scars ca. 0.5 cm wide. Crowncomposed of ca. 8 leaves, these sometimestardily abscissing, the whole crown tendingio trap leaf litter. Crownshaft to 13-25cm long, 3-7 cm diam., often partiallyobscured by the marcescent leaf sheaths.Leaf variably dissected; leaf sheaths l3-20 cm long, dull green to brown, oftentinged purple, drying pale brown, striate,bearing thin pale brown scalesi petioleabsent to very short, not exceeding 5 cmlong; rachis to I m long, adaxially chan-nelled near the base, abaxially rounded orangled, pale brownish green, sometimestinged purple; blade irregularly dissected,leaflets adaxially dark shiny green, slightlypaler abaxially, usually borne close

DRANSFIELD AND CHONG-KEAT: NEW SPECIES OF ARECA B I

2. Areca tunltu in flower, Upper Perak. Photo byC.-K. Lilu.

together, 5-24 on each side of the rachis,varying from narrow to broad, 22-65 x0.7-10 cm, composed of l-6 folds, acu-minate and somewhat sigmoid except forthe terminal shallowlyJobed pair, mainveins bearing minute brown punctiformscales. Inflorescence sometimes burstinethrough marcescent sheaths. erect, 8.5:22 cm, almost always branching to I orderonly, very rarely the basalmost branchbearing a branch of the second order, allaxes cream-colored, turning yellowishorange, greenish or deep purple; prophyll8-22 x 2.5-4 cm, ancipitous, elliptic-lanceolate, winged throughout, creamybrown to pale green, tinged with carminepurple, becoming striate on drfng, bearingbands of scattered pale brown scales;

F

1. Arecatunku. A, leaf t ip x/s;B, leal sheath x%;C,basalport ionof lealx7t ; D, inf lorescence x?4;E,staminate flower in vortical section x2; F, pistillate flower in vertical section x2; G, infructescence xTti H,

fruit in vertical section xTt. Dram by M. M. Watt frorn Dransfield JD51Z8.

82 P R I N C I P E S [Vor. 36

3. Inflorescence of Areca tunku, Upper Perak. 4. Frrlirt of Areca tunku, Uppet Perak. Photos by C.-K.Lim.

peduncle 20-30 x 7-10 x 5 mm gla-brous, bearing an inconspicuous, incom-plete, low ridgeJike peduncular bract ca.I mm high, just above the prophyll scar;rachis to 7 cm long; rachillae 6-12, verystiff and stout. borne in two neat rows oneither side ofthe rachis, congested at first,later often widely spreading, 5- I 2 x 0.2-0.4 cm, sometimes slightly curved, bearingflowers only along one side (the distal side);triads borne only at the very base of therachillae, l-6 per rachilla, rarely absent,distally the rachillae bearing paired or sol-itary staminate flowerso the flowers cream-colored or greenish tinged, often markedlycontrasting with the purplish rachillae. Sta-minate flowers terete, ca. 4-10 x 1.5-2mm; calyx cup-shaped, sometimes stronglyexplanate, to 0.75 mm high, three-lobed,the lobes triangular to I x I mm; petals3, distinct, 4.5-10 x L.5-2.5, abaxiallyslightly striate; stamens 6, filaments 0.75-

1.5 mm, anthers 2.5-5.5 x I mm, api-cally and basally sagittate; pollen mono-sulcate with finely punctate tectate exine;pistillode minute. Pistillate flowers atanthesis cream-colored, borne on enlargedrachillae; buds varying greatly in sizedepending on stage of development, justbefore anthesis to 19 x 9 mm; sepals 3,strongly imbricate, irregularly ovate l0 x9 mm; petals 3, basally strongly imbricatel0 x 9 mm, with triangular valvate tipsto 5 x 5 mm; staminodes 3, irregularlydentiform to strap-shaped; ovary ovoid 14x 4 mm, stigmas 3, strongly adpressed inbud, expanding and becoming reflexed atanthesis, white, fleshy, triangular ca. 5 x5 mm. Fruit borne on the enlarged, darkbrown or blackened rachillae, up to about12 fruits developing on a single inflores-cenee; mature fruit 3-4.5 x 1.5-3 cm,dull purplish green to brown, with black-ened stigmatic remains borne on a white-

re92l

ringed beak to 12 x 6 mm; epicarp smooth,becoming striate on dryng; mesocarp thin,pale, inner fibers of mesocarp broad, black,conspicuous, closely adhering to the endo-carp; endocarp thin, closely adhering tothe seed. Seed to 25 x l5 mm; endospermdeeply ruminate, embryo basal. Seedlingleaf bifid (Fis. l).

Distribution: Sumatra (Sumatera Utara)and Peninsular Malavsia.

S p ecim,ens Examin ed : PENINSULARMALAYSIA. Terengganu: Besut , UluSungei Kemia, alt. 530 m. CockburnFRIB2l2 (KEP); Besut. Ulu Setiu ForestReserve, alt. 500 m, Dransfeld et al.JD5I78 (holotype K: isotype KEP), alt.5O m, Dransf.eld et al. JD5 I 69 (K, KEP);Ulu Nerus Forest Reserve. alt. 200 m.Dransf.eld et al. JD65I I (K, KEP). Johor:Labis Forest Reserve. lf

-ong Khoon Meng

FRI 32485 (KEP). Perak: Upper Perak,Belum Forest Reserve. alt. 800 m. LimChong-Keat et aL.90 069. 90 , '524,90/

542 (K, KEP).SUMATRA. Sumatera L tara: Langkat,

Bohorok, Bukit Lar.'ang. alt. 500 m,Dransf.eld et al. JD3ll+ (BO), JD3l45(BO), JD3l70 (BO), JD3263 (BO, K) .

In Peninsular Malavsia -lreca tunku rsa palm of hill dipterocarp forest: in Suma-tra it occurs in similar habitats. The NorthSumatran population seems to consist ofplants at the small end of the range ofvariation. Within populations in Tereng-ganu, the range of variation is consider-able, making suspect anv separation of theSumatran plants on the basi-. of size alone.

The uniseriate staminate florrers (Fig.l) suggest that Areca tunku is a memberof Wendland and Drude's section Arecellain Furtado's sense (Furtado 1933). Theswollen frequently purplish rachillae (Figs.1,4) seem to suggest a relationship withAreca jugahpunya J. Dransf. and A.ahrnadii J. Dransf. (Dransfield 1984), twoBornean species, However, these two spe-cies are immediately distinguishable by their

DRANSFIELD AND CHONG-KEAT: NEW SPECIES OF ARECA

acaulescent habit; furthermore A. ahma-dii has interfoliar inflorescences with verylong peduncles and slender, less stronglybeaked fruit, while A. jugahpunya is amuch more massive palm, with a shortpeduncle as in A. tunku, but with muchlarger inflorescences with many (20)rachillae and large staminate flowers withpetals connate for half their length. Thepeduncle form and colors of the inflores-cence make A. tunku especially distinctiveand striking.

Acknowledgments

We should like to thank Saw Leng Guanof Forest Research Institute Malaysia andMohd Noor Jamalul Lail and Ismail Ahmadof Penang Botanical Gardens for their helpand encouragement in the herbarium andfield. Dato' Mohd. Darus bin Hj. Mahmud,the Director General, Forestry Depart-ment, Malaysia, Dato' Ismail bin Awang,Director, Perak State Forestry Depart-ment and Joseph Anthony, District ForestOfficer, Gerik, Perak all helped LCK andhis colleagues in providing encouragementand access to Belum Forest Reserve. MaryMillar Watt prepared the drawing.

LtrsneruRn Crrnl

DRANSFIELD, J. 1978. Systematic notes on Malayanrattans. Malays. Forester 4l(4): 325-345.

1982. Pinanga cleistantha, a new spe-cies with hidden flowers. Principes 26: 126-129.

1984. The genus Areca (Palmae: Are-coideae) in Borneo. Kew Bull. 39: I-22.

FURTADo, C. X. 1933. The limits of the genusAreca L. and its sections. Feddes Repertorium33:217 239.

Mocne, J. P. 1984. Three new species of Salacca(Palmae) from the Malay Peninsula. Fed. Muse-ums Journ. 29: I-19.

RIDLEY, H. N. 1907. Materials for a flora of theMalayan Peninsula. Part 2. Methodist Publish-ing House, Singapore.