Livistona halongensis T.H.Nguyen & Kiew, Gard. Bull. Singapore 52: 198 (2000)

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Distribution

Map uses TDWG level 3 distributions (http://www.nhm.ac.uk/hosted_sites/tdwg/geogrphy.html)
Vietnampresent (World Checklist of Arecaceae)B
Vietnam. Islands in Ha Long Bay. (Dowe, J.L., A taxonomic account of Livistona R.Br. (Arecaceae))A

Habitat

  • Confined to limestone islands, in soil-filled crevices on rocky limestone substrate, sometimes gregarious, 100-300 m alt. Flowers May-Jun; fruits July. (Dowe, J.L., A taxonomic account of Livistona R.Br. (Arecaceae))A

Discussion

  • Livistona halongensis was described by Nguyen and Kiew (2000) from limestone islands in Ha Long Bay, Gulf of Tonkin, Vietnam, based on Nguyen Tien Hiep NTH 2630. This is the only Livistona known to be restricted to limestone. It was previously mentioned by Yang (1996) as an ?unidentified species of Livistona? from Cat Ba Is.Livistona halongensis is a smallish sub-canopy palm to 10 m tall; leaves are small and regularly segmented; segment apices are rigid to semi-pendulous, and with a bifurcate cleft to 40% of the segment length; the inflorescence is unbranched, extending vertically above the crown by about 1 m, and with up to 7 partial inflorescences; bracts are tightly tubular; flowers are cream-yellow; fruit are globose, to 12 mm diam., and glossy dark green at maturity. (Dowe, J.L., A taxonomic account of Livistona R.Br. (Arecaceae))A

Conservation

  • Lower risk, conservation dependent. (Dowe, J.L., A taxonomic account of Livistona R.Br. (Arecaceae))A

Description

  • Hermaphroditic palm. Trunk to 10 m tall, ca 20 cm dbh, leaf scars conspicuous, internodes narrow. Leaves ca 40 in a ± globose crown; petiole 125-130 cm long, ca 2 cm wide at the base, ca 1.5 cm wide distally, adaxially flat, green with a light yellow band along the margin, margin with irregularly spaced triangular hooked dull orange spines along entire length but more aggregated proximally; leaf-base fibrous, appendage triangular,rich brown, fibrous, distally tattered into ribbons; hastula papery, to 2.5 cm high; lamina costapalmate, regularly segmented, circular, 75-80 cm long, undulate, adaxially dark green, abaxially lighter green; mid-leaf segments ca 4 cm wide where the segments diverge; lamina divided for 42-73% of its length, with 45-64 segments, depth of apical cleft ca. 40% of the segment length, apical lobes rigid to semi-pendulous; parallel veins 11-13 each side of midrib; transverse veins thinner than parallel veins; basal part of outer segment with a 2 cm long row of fine teeth on the margin. Inflorescences unbranched at the base, ca 340 cm long, erect, projecting vertically above the crown and extending well beyond the limit of the crown, branched to 3 orders; partial inflorescences 6-7, longest to 95 cm; peduncle ca 160 cm long, 2 cm diam.; prophyll to 33 cm long, basally 5 cm wide, distally to 3 cm wide; peduncular bracts 5, each ca 50 cm long, tightly tubular, thick, leathery-fibrous; rachis bracts ca 27 cm long, otherwise similar topeduncular bracts; rachillae 1.0-1.5 mm diam., cream, velvety tomentose. Flowers in pairs on pedicel ca 0.3 mm long, ovoid in bud, pale creamyellow; sepals basally fused with lobes ca 1 mm long, glabrous; petals ca 2 mm long; stamens ca 1 mm long, subulate, staminal tube rich brown, filament very short; anthers white, ca 0.3 mm long; carpel obovoid, deeply ridged, dark reddish brown, ca 1 mm long; style pale brown, ca 0.3 mm long; stigma minute. Fruit globose, 10-12 mm diam., epicarp smooth, glossy dark green; mesocarp leathery; endocarp crustaceous, brittle, ca 0.75 mm thick; endosperm intruded by seed coat to ca halfway through; pedicel 2-5 mm long. Eophyll not seen. (Dowe, J.L., A taxonomic account of Livistona R.Br. (Arecaceae))A

Materials Examined

  • Specimens examined: VIETNAM: Quang Ninh Prov., Ha Long Bay, Nguyen, Averyanov & Nguyen NTH2630 (HN holotype, SING); Quang Ninh Prov., Ha Long Bay, 15 Jul 1999, Nguyen & Kiew s.n. (HN); Ha Long Bay, 11 Apr 2000, Nguyen & Kiew s.n. (HN); Hai Phong Prov., Cat Ba NP, limestone hill, ca 300 m alt., Nguyen Tien Hiep NTH 4853 (HN). (Dowe, J.L., A taxonomic account of Livistona R.Br. (Arecaceae))A

Bibliography

A. Dowe, J.L., A taxonomic account of Livistona R.Br. (Arecaceae)
B. World Checklist of Arecaceae