Orania tabubilensis A.P.Keim & J.Dransf.

Keim, A.P. & Dransfield, J. 2012. Kew Bulletin 67: 127. https://doi.org/10.1007/s12225-012-9356-6

Vernacular

lai (Sorong, Matbat language).

Morphology General Habit

Small palm

Morphology Trunk

Trunk c. 5 m tall, c. 10 cm diam. (DBH)

Morphology Reproductive morphology Inflorescences

Inflorescence spreading, branching to 2 orders, c. 180 cm long; prophyll c. 52 cm long, distinctly pointed, woody, stiff when dry; peduncle c. 60 cm long, densely covered with red-brown tomentum; peduncular bract apparently one, woody, persistent; rachis c. 120 cm long, densely covered with red-brown tomentum, number of first order branches 25, rachillae rather thick, c. 20 – 50 cm long, slightly zigzag, bearing 42 – 102 flower clusters, bearing triads up to 10 – 25 cm from base-triads arranged in the proximal half part, the basal c. 1 – 1.5 cm devoid of flowers, triads c. 1.5 – 2 cm distant, rachilla densely covered with red-brown tomentum

Morphology Reproductive morphology Flowers

Pistillate flowers with calyx of 3 minute sepals, 1.5 – 2 mm long; corolla with 3 free petals, c. 2 – 2.5 mm long, 2 mm wide; staminodes 6, c. 0.5 – 1 mm long; gynoecium dark-brown, c. 2 mm long, 2 mm wide, stigma of 3 elongate lobes, 0.5 mm long Staminate flowers with calyx of 3 united sepals, c. 1 mm long; corolla with 3 free petals, c. 6 mm long, 1 – 1.5 mm wide; stamens 6, filaments free, dark-brown, c. 0.5 – 0.75 mm long, anthers elongate-lanceolate, pale creamy yellow, always free, c. 4 mm long; pistillode absent

Morphology Reproductive morphology Fruits

Fruit globose, juvenile, c. 2 cm diam., stigmatic remains sub-basal-Embryo placed below middle line of seed

Morphology Leaves

Eophyll unknown Leaves 8 in crown, arranged distichously, c. 380 cm long, leaf-sheath c. 160 cm long, 18 cm wide near base, adaxial surface glabrous, abaxial surface with dense red-brown tomentum covering, margin disintegrating into fibres, fibres straight; petiole covered with red-brown tomentum, c. 10 – 11 cm long, c. 1.5 – 2 cm diam.; rachis c. 210 cm long, densely covered with red-brown tomentum, c. 1.5 – 2 cm diam.; leaflets elongate-lanceolate, arranged in more than one plane, absent in centre of rachis, c. 35 on either side, c. 90 cm long, 4 – 4.5 cm wide each, distance between 2 leaflets c. 7 cm in near middle part of rachis; adaxial surface glabrous, midrib robust with slight red-brown tomentum covering, other ribs slender; abaxial surface glabrous with slight red-brown tomentum covering on margins, midrib less robust than adaxial surface, other ribs slender

Distribution

This species possesses an amazingly wide disjunct distribution. In Papua this species is found in Sorong, the most western tip of the Bird’s Head area. In Papua New Guinea the species is found in an area close to a road from Tabubil to Ok Tedi copper mine, 8.5 km N of Tabubil, c. 2 km NW of Finalbin, North Fly Distr., Western Province, Papua New Guinea. Map 6.

Ecology

In Sorong, Papua this species is found in the lowland forest at altitude about 10 m above sea level. On the contrary, in Papua New Guinea it is found in montane hill forest on limestone soil at about 1000 m above sea level.

Conservation

Vulnerable (VU D2). Although known only from two collections, the palm occurs in some abundance in montane forest on rocky limestone slopes unlikely to be used for agriculture.

Note

From Tabubil, the type locality. Prior to this study, Orania archboldiana was the only species in the genus known to have its leaflets arranged in more than one plane (Essig 1980), but that species has spirally arranged leaves. A recently collected specimen from Sorong (R. A. Maturbongs RAM 705) with distichous leaves and irregularly arranged leaflets seems also to belong in O. tabubilensis, despite the astonishingly wide disjunction and difference in habitat preference. The distichous leaf arrangement immediately distinguishes this species from the other species that possesses the same leaflet arrangement, O. deflexa. For a complete list of differences with O. archboldiana and O. deflexa, see Table 12.

Use

Unknown.