1. Family: Arecaceae Bercht. & J.Presl
    1. Actinorhytis H.Wendl. & Drude

      1. This genus is accepted, and its native range is Papuasia.

    [PW]
    Diagnostic
    Tall solitary tree palm of New Guinea and the Solomon Islands with slender crownshaft, strongly arching leaves and highly branched inflorescence bearing large fruit with deeply ruminate endosperm.
    Biology
    In the wild, it grows in lowland tropical rain forest at altitudes up to about 1000 m above sea level.
    Distribution
    A single species, Actinorhytis calapparia, native to New Guinea and the Solomon Islands, now widespread as an ornamental or ceremonial plant in Southeast Asia.
    Morphology
    Leaf (Tomlinson 1961), root (Seubert 1998a, 1998b) and fruit (Essig et al. 1999).
    General Description
    Tall, solitary, unarmed, pleonanthic, monoecious tree palms. Stem erect, bare, conspicuously marked with leaf scars, with a large mass of roots at the base. Leaves pinnate, arching, neatly abscising; sheaths tubular, forming a long, slender, well-defined crownshaft, bearing scattered caducous scales, the mouth with a short ligule; petiole very short in mature individuals (long in juveniles), adaxially channelled or flattened, abaxially rounded, densely caducously tomentose; rachis conspicuously down-curved toward the tip; leaflets very numerous, close, regularly arranged, single-fold, acute, acuminate or briefly bifid, the margins thickened, adaxially glabrous, abaxially with minute dot-like scales and conspicuous ramenta along the midrib, transverse veinlets obscure. Inflorescences infrafoliar, erect in bud, becoming horizontal or pendulous, branching to 3 orders proximally, to 1 order distally, protandrous; peduncle short, winged at the very base, grossly swollen just above the base in the centre, caducously tomentose; prophyll inserted near the base of the peduncle, tubular, beaked, 2-keeled, entirely enclosing the inflorescence in bud, sparsely scaly, splitting abaxially, deciduous; peduncular bract, inserted just above the prophyll, similar to the prophyll but scarcely 2-winged, deciduous; subsequent bracts low, triangular, inconspicuous; rachis longer than the peduncle, ± elliptic in cross-section, bearing relatively few, large, spirally arranged first-order branches, with conspicuous, bare, proximal portions; rachillae rather stiff, elongate, bearing spirally arranged triads in the proximal 1/2 to 2/3, and paired or solitary staminate flowers distally, or rarely, bearing only staminate flowers; rachilla bracts low, rounded, quite conspicuous, tending to form very shallow pits; floral bracteoles sepal-like. Staminate flowers asymmetrical in bud; sepals 3, distinct, imbricate, ± triangular-tipped, keeled; petals 3, distinct, ± ovate, valvate, ± 2–3 times as long as the sepals; stamens 24–33 or more, exserted at anthesis, filaments slender, elongate, inflexed at the tip, anthers medifixed, narrow oblong, ± versatile, latrorse; pistillode columnar, ± as long as the stamens in bud, shorter when stamens exserted. Pollen ellipsoidal asymmetric, occasionally elongate; aperture a distal sulcus; ectexine tectate, perforate-rugulate, aperture margin similar or slightly finer; infratectum columellate; longest axis 33–50 µm [1/1]. Pistillate flowers globular, at anthesis much larger than the staminate; sepals 3, distinct, imbricate, rounded; petals 3, ±twice as long as the sepals, distinct, broadly imbricate with conspicuous, triangular, valvate tips; staminodes 3, narrow triangular, flattened; gynoecium ovoid to obovoid, unilocular, uniovulate, stigmas 3, large, fleshy, recurved, ovule laterally attached near the apex of the locule, hemianatropous. Fruit very large, ovoid, ± beaked, green turning red at maturity, perianth whorls persistent, stigmatic remains apical; epicarp smooth, mesocarp with thin flesh and abundant anastomosing fibres adhering to the endocarp, endocarp closely adhering to the seed, thin, ± bony. Seed globose, with lateral, longitudinal hilum, endosperm deeply ruminate, with a central, irregular hollow; embryo basal. Germination adjacent-ligular; eophyll bifid. Cytology not studied.
    Vernacular
    Pinang penawar, pinang mawar.
    [PW]
    Use
    Actinorhytis calapparia is widely planted in Southeast Asia and Malesia; it is very decorative, but the main reason for its cultivation by villagers is as a magic or medicinal plant. The seed may also be chewed as a betel substitute.

    Images

    Distribution

    Native to:

    New Guinea, Solomon Is.

    Introduced into:

    Malaya, Sumatera, Thailand

    Actinorhytis H.Wendl. & Drude appears in other Kew resources:

    First published in Linnaea 39: 184 (1875)

    Accepted by

    • Govaerts, R. & Dransfield, J. (2005). World Checklist of Palms: 1-223. The Board of Trustees of the Royal Botanic Gardens, Kew.
    • Govaerts, R. (1995). World Checklist of Seed Plants 1(1, 2): 1-483, 1-529. MIM, Deurne.

    Literature

    Palmweb - Palms of the World Online
    • J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008

    Sources

    Interactive Key to Seed Plants of Malesia and Indo-China
    The Malesian Key Group (2010) Interactive Key to Seed Plants of Malesia and Indo-China (Version 2.0, 28 Jul 2010) The Nationaal Herbarium Nederland Leiden and The Royal Botanic Gardens Kew

    Kew Backbone Distributions
    The International Plant Names Index and World Checklist of Selected Plant Families 2020. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

    Kew Names and Taxonomic Backbone
    The International Plant Names Index and World Checklist of Selected Plant Families 2020. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

    Palmweb - Palms of the World Online
    Palmweb 2011. Palmweb: Palms of the World Online. Published on the internet http://www.palmweb.org. Accessed on 21/04/2013
    Content licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License http://creativecommons.org/licenses/by-nc-sa/3.0