Areca vestiaria Giseke Species Incertae Sedis:

TAXONOMIC TREATMENT A RECA L. S P . P L .: 1189 1753. T YPE : A RECA CATECHU L. Mischophloeus Scheff., Ann. Jard. Bot. Boitenzorg 1: 115, 134 1876. Gigliolia Becc., Malesia 1: 171 1877. Pichisermollia H.C. Monteiro, Rodriguesia 28: 195 1976. Description: Solitary or clustering, very small to moderate, acaulescent to erect, unarmed, pleonanthic, monoecious palms. S TEM slender to moderate, occasionally stilt-rooted, internodes very short to elongate, leaf scars often conspicuous. L EAVES undivided and pinnately ribbed, with or without an apical notch, or pinnate; sheaths forming a well defined crownshaft with leaves neatly abscising, or rarely crownshaft not well developed when leaves marcescent or sheaths partly open; petiole present or absent, adaxially channelled or rounded, abaxially rounded, glabrous or variously indumentose; leaflets regularly or irregularly arranged, 1–several fold, acute, acuminate or lobed, the lobes corresponding to folds, the apical pair almost always lobed, held in one plane except to one species A. mandacanii in different planes, very rarely A. insignis with basal auricles reflexed across the rachis, blade variously scaly or hairly, transverse veinlets obscure. I NFLORESCENCE erect or pendulous, mostly infrafoliar, rarely interfoliar in acaulescence species with marcescent leaf sheaths e.g. A. jugahpunya, branched to 3 orders basally, very rarely spicate, protandrous or very rarely recorded as protogynous; peduncle very short to long; prophyll thin, membranous, enclosing the inflorescence in the bud, quickly splitting and falling, other bracts very inconspicuous; rachis shorter or longer than the peduncle; rachillae glabrous or variously indumentose; rachilla bracts minute; triads confined to the proximal part of the main axis, or to the proximal part of each order of branching, or rarely to a subdistal part of main axis only; rachillae otherwise bearing solitary or paired staminate flowers arranged spirally, distichously, or in 2 approximate rows on one side of the rachilla, the rachilla tips sometimes devoid of the flowers. S TAMINATE FLOWERS frequently minute, sessile, or with a stalk formed from the receptacle; calyx with 3 distinct, slightly imbricate, triangular sepals or cupular with triangular lobes, corolla with 3 triangular, valvate petals, rarely briefly connate at the base, much longer than the sepals; stamens free or briefly epipetalous, 3, 6, 9, or up to 30 or more, filaments short to elongate, anthers linear or sinuous, sometimes very irregular, lartrorse or rarely opening by apical pores; pollen elliptic or circular, monosulcate with the sulcus short to extensive, trichotomosulcate, monoporate ulcerate, or triporate, with perforate, foveolate, or finely to coarsely reticulate tectate or intectate exine; pistilode present and conspicuous as trifid coloum as long as the stamens, or minute, or often absent. P ISTILLATE FLOWERS sessile, usually much larger than the staminate, ± globular; sepals 3, distinct, imbricate; petals similar to sepals, 3, distinct, sometimes valvate at the very tip, otherwise imbricate; staminodes 3–9 or absent; gynoecium unilocular, uniovulate, globose to ovoid, stigma 3, fleshy, triangular, ± reflexed at anthesis, ovule anatropous, basally attached. R ACHILLA distal to pistillate flowers drying after anthesis, portions bearing fruits sometimes becoming brightly coloured. F RUITS globose, ovoid, or spindle-shaped, often brightly coloured, rarely dull brown or green, stigmatic remains apical; epicarp smooth, shiny or dull, mesocarp thin to moderately thick, fleshy or fibrous, endocarp composed of robust longitudinal fibers, usually closely appressed to the seed, becoming free at the basal end or not. S EED conforming to the fruit shape or slightly hollowed at the base, with basal hilum and raphe branches anastomosing, endosperm deeply ruminate; embryo basal. G ERMINATION adjacent–ligular; eophyll bifid or rarely entire with minute apical cleft. C ITOLOGY 2n = 32. Distribution: India and south China, through Malesia to New Guinea and the Solomon Islands. Number of species: 41 species. I NFRAGENERIC CLASSIFICATION OF THE GENUS A RECA K EY TO S UBGENUS OF A RECA 1. Staminate flowers uniseriate, or distichous andor alternate; sepals free or sometimes connected; stamens 3–6…………………………………………....….Subgenus Areca 1. Staminate flowers all or small portions spirally arranged; sepals united; stamens 6– more………………………………………………………….Subgenus Beccarioareca The infrageneric classification is mainly based on the result of the molecular phylogenetic analysis of the genus Areca using two low-copy nuclear genes – PRK and RPB2 Heatubun et al. in prep.. The consensus tree from the combined analysis showed that the genus Areca is monophyletic and comprises two lineages with strong support in both Bayesian and Parsimony analysis. Two lineages represent the two subgenera, but the groups clades do not correspond with the previous sections proposed by Furtado 1933. This result has taxonomic consequences; we recognise only two subgenera to accommodate the two lineages evolutionary lines within the genus and without any sections. After optimization the morphological characters to the phylogenetic tree, only two characters – staminate flower arrangement spiral and secund or distichous, and sepals of staminate flowers free and united – support the topology of the tree. These characters are used here as diagnostic characters to define two subgenera in Areca – subgenus Areca and Beccarioareca.

I. Subgenus Areca

Blumeoareca Furtado, Repert. Spec. Nov. Regni. Veg. 36: 225 1933. Type species: A. catechu L.

1. A

RECA AHMADII J. D RANSF . Areca ahmadii

J. Dransf., Kew Bull. 39: 4 1984.

Type: B ORNEO , Sarawak, 1 st Division, Semengoh Forest Reserve, i.1980, Lai Shak Teck S 38946 holotype: K; isotypes: BH, BO, KEP, L, SAR. Distribution: Borneo Sarawak.

2. A

RECA BAKERI H EATUBUN SP . NOV . F IG .1. Type: B ORNEO , Sarawak, cultivated in the Semengoh Forest Arboretum, 42 m, 22.iv.1996, Baker et al. 716 holotype: K; isotypes: KEP, SING, SAR. Diagnosis: Ad subgenerum Arecam, a ceteris speciebus Borneensibus habitu acaule– caespitoso, petiolis longis 100–105 cm, inflorescentia erecta rigida, floribus staminatis distichiss, floribus foemineis singulariter dispositis distincta. Description: Undergrowth palmlet densely clustered with c. 20 stems in a clump to 1 m high tall, unarmed. S TEM subterranean to very short −1 cm, c. 2 diam.; internodes very close 0.5 −1 cm long, not conspicuous, covered by marcescent leaf sheaths. L EAVES 4 −6 in crown, litter trapping, pinnate, 140 −200 cm long excluding petiole; sheath tubular, 20 −31 cm long and 3−4 cm wide, smooth, not fibrous, yellowish green; crownshaft well defined, up to 40 cm long and up to 4 cm diam.; petiole 100 −105 cm long, channelled adaxially, rounded abaxially; rachis ascending but not arching, with adaxial longitudinal ridge, rounded abaxially; blade with slightly irregularly arranged leaflets, 7 −8 broad on each side; leaflets near petiole c. 52 × 6.4 −14 cm, with 7−9 folds, sigmoid, the middle leaflets 57 −59 × 4.5−10 cm, with 5−9 folds, slightly sigmoid and the terminal leaflets c. 42 × 11 cm, with up to 10 −11 folds, slightly sigmoid, tips pointed except for the terminal slightly oblique-lobed, papery, darker adaxially than abaxially. I NFLORESCENCE infrafoliar, erect, bursting out among marcescent sheaths, 20 −26 cm long and 4.5−12.5 cm wide, protandrous, branching to 1 order; peduncle 6 −10 cm long, pale yellowish green; prophyll not available; rachis yellowish green; rachis bracts caducous; rachillae 11 −13, 8.5 −14 cm long and 3.5−5.6 mm wide, very stiff and stout, flattened, pale green, elongate. S TAMINATE FLOWERS small, triangular, c. 6.2 × 3.1 mm, asymmetric; sepals 3, low; petals 3, triangular, small, striate; stamens 6, small, anthers shorter than the filaments; filaments slender, elongate; pistilode c. 2.5 × 1.0 mm, pointed. P ISTILLATE FLOWERS larger than the staminate, triangular, borne on the enlarged rachillae, only one flower on each rachillae, buds varying greatly in size depending on stage of development, c. 17 mm long and 8 mm wide in late anthesis; sepals 3, strongly imbricate, c. 7 × 7 mm, triangular, asymmetrical, striate; petals 3, imbricate, triangular, c. 12.5 × 6.5 mm, striate; gynoecium c. 10.5 mm long and 4 mm wide at the base; stigma c. 8 mm long, pointed with 3 lobes, split 8 mm to the base; style c. 1.5 mm long; staminodes c. 6, irregularly dentiform, 0.5 −1 × 0.25−0.5 mm. F RUITS elongate, sickled-shaped, 6.0 −6.5 × 1.3−1.45 cm in young fruits, beak 1.4 −1.5 mm; epicarp smooth, shiny, dark green young, mature fruits and seed not known; endosperm sparsely ruminate. Distribution and Ecology: Only known from very limited collections from 4 th Division of Sarawak in Northern Borneo and from the plant cultivated in Semengoh Forest Arboretum