Pinanga rupestris J.Dransf.

First published in Kew Bull. 46: 693 (1991)
This species is accepted
The native range of this species is Borneo (Sarawak). It is a shrub and grows primarily in the wet tropical biome.


habitatione egregia verosimiliter affinis P. rivulari Becc. inflorescentia spiciformi sepalis floris pistillati connatis et ramificatione internodiali sed lamina angusta integra breve bifida statim distinguibilis.
This remarkable little 'pinang' is found only on the great sandstone cliffs and boulders of Bako National Park.
General Description
Diminutive clustering palmlet, erect or more usually pendulous from crevices in sandstone rock faces. Stems rarely exceeding 60 cm long, usually much less, c. 4-6 mm diam., conspicuously marked with nodal scars, inter- nodes 1-3 cm, surface with scattered brown scales, stem base producing aerial roots and dense clusters of sucker shoots, the stem also frequently producing bulbil-like shoots from the middle of the distal internodes. Crown of about 6 leaves, the sheaths forming an elongate crownshaft; leaf sheaths c. 80 x 7 mm, striate on drying, covered in scattered dull brown scales, distally with a rapidly disintegrating laciniate ocrea to 16 mm; petiole of leaves of mature stems c. 8-17 cm, c. 3 mm diam., ± triangular in cross section, bearing scattered scales when fresh; blade dull brown or greenish brown when dry, narrow, entire, bifid, to 50 cm long, gradually widening from the base to 6 cm near the tip, usually shorter and narrower, split to 7.5 cm, the two halves with c. 6 shallow lobes to 7 mm deep; adaxial surface minutely punctate, abaxial surface bearing inconspicuous thin grey indumentum. Inflorescence unbranched, pendulous, 6 cm long; prophyll c. 6 x 1.4 cm; peduncle very short, not exceeding c. 7 mm; rachilla surface hairy; triads strictly distichous, borne in a plane radial to the stem, each subtended by a low rachilla bract to 1 mm high. Staminate flowers ± triangular ovate in outline, laterally flattened or curved by close packing; calyx irregularly 3-lobed, the lobes 1-2 mm high; petals cream-coloured, fleshy, irregular, two c. 6.5 x 3 mm, the third c. 6.5 x 4.5 mm; stamens 7-8, filaments c. 1 x 0.2 mm, anthers c. 2 x 0.6 mm, with broad connectives. Pollen grains monosulcate, ellipsoid in apertural view; long axis (31-)33.3(-36) µ/m, short axis (24 -)26.2(-30) µ/m, wall thickness c. 2 ,im; sulcus membrane not observed, sulcus somewhat longer than long axis; exine intectate, clavate, the larger clavae interspersed with smaller diameter, shorter clavae, clavae not modified at sulcus margin. Pistillate flower very low; calyx tubular, ± striate, c. 0.8 mm high, very shallowly 3-lobed; petals imbricate, ovate, c. 0.8 mm long, the margins sparsely ciliate; staminodes lacking; ovary c. 0.8 mm diam., tipped with an irregularly lobed stigma. Fruit not known.
It is by no means abundant, but is very distinctive. No fruits have been found although dead inflorescences can be seen on herbarium specimens and in the field. How the palm is dispersed to crevices in vertical cliffs is a mystery.


  • Herbarium Catalogue Specimens

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  • Kew Backbone Distributions

    • The International Plant Names Index and World Checklist of Vascular Plants 2023. Published on the Internet at and
    • © Copyright 2022 World Checklist of Vascular Plants.
  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2023. Published on the Internet at and
    • © Copyright 2022 International Plant Names Index and World Checklist of Vascular Plants.
  • Palmweb - Palms of the World Online

    • Palmweb 2011. Palmweb: Palms of the World Online. Published on the internet Accessed on 21/04/2013
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