Tahina J.Dransf. & Rakotoarin.
  • Bot. J. Linn. Soc. 156: 81 (2008) 


Notes: Distribution: Madagascar

General Description

Massive, solitary, unarmed, hapaxanthic, hermaphroditic, tree palms. Stem erect, rather distantly ringed with leaf scars. Leaves induplicate, costapalmate, marcescent in immature individuals, tending to abscise under their own weight in trunked individuals; sheath with a conspicuous triangular cleft below the petiole, the margins tending to erode into broad lobes; petiole massive, long, covered with white wax, adaxially deeply channelled, abaxially rounded, margins smooth, adaxial hastula well developed, abaxial hastula a hard low rather irregular crest at the base of the lamina; blade divided to ca.1/2 its radius into multi-fold segments, these in turn more shallowly divided into single-fold segments, themselves shallowly divided along the abaxial folds, main abaxial ribs of blade very conspicuous, very crowded at the base of the blade, some much more robust than others, the less robust ribs tending to be inserted in a more adaxial position compared with the robust ribs; segments with prominent longitudinal veins and abundant irregularly arranged transverse veinlets, glabrous, the undersurface of the blade with thin white wax. Inflorescences above the leaves, subtended by reduced, scale like leaves, forming a massive, compound inflorescence-like structure; individual inflorescences branched to the third order, branches ending as rachillae; prophyll of inflorescences and first order branches 2-keeled, this case distal to the first and second flowers a few empty tubular bracts. Flowers borne on short stalks; distal to this, the flower with a stalk formed by the base of the calyx and the receptacle; calyx tubular basally, with 3 low, triangular lobes; petals ± boat-shaped, basally imbricate, the margins usually inrolled, apically somewhat cucullate, strongly reflexed at anthesis and with a glandular swelling at the base of each lobe; stamens 6, filaments terete, tapering from a fleshy base; anthers elongate, basifixed, introrse; gynoecium tricarpellate, syncarpous, triovulate, ovarypyramidal, angled and grooved, style short, slightly 3-grooved, stigma scarcely differentiated, ovule basally attached, anatropous. Pollen ellipsoidal, bi-symmetric or slightly asymmetric; aperture a distal sulcus; ectexine tectate, coarsely perforate-rugulate, aperture margin slightly finer; infratectum columellate; longest axis 25–55 µm; post-meiotic tetrads tetrahedral. [1/1]. Fruit ellipsoid, single-seeded with apical stigmatic remains; epicarp smooth, mesocarp fleshy and ± fibrous, endocarp scarcely distinguishable, membranous. Seed globose, with basal hilum, and deep grooves corresponding to the rapheal bundles, endosperm strongly ruminate without a central hollow; embryo subbasal. Germination remote-ligular; eophyll palmate. Cytology unknown.

Diagnostic Description

Spectacular massive solitary hapaxanthic hermaphroditic fan palm of north-western Madagascar, with huge leaves and unarmed petioles with a distinctive triangular cleft at the base of the petiole, and huge suprafoliar compound inflorescences.

Morphology

Not studied.

Biology

It grows at low elevation on seasonally flooded soils at the foot of a karst limestone outcrop; there are 91 individuals of varying size and a few hundred 1-leaf seedlings originating from the 2007 fruiting known. When in flower, the immense compound terminal inflorescence appears to go through three successive waves of anthesis. Nectar production is so copious that the entire inflorescence appears coated with honey, attracting large numbers of bees, wasps and flies. Greater Vasa Parrots (Coracopsis vasa) attack the young fruit (N. and X. Metz, pers. comm.). Nothing is known of fruit dispersal.

Distribution

Tahina spectabilis is known from a single locality in north-western Madagascar.

Uses

No local uses have been recorded.

Common Names

Dimaka, a name also applied to Borassus, Bismarckia and Dypsis decipiens.

Distribution Map

 
  • Native distribution
Found in
  • Africa Western Indian Ocean Madagascar

  Bibliography

  • 1 Dransfield, J., Uhl, N.W., Asmussen, C.B., Baker, W.J., Harley. M.M. & Lewis, C.E. (2008). Genera Palmarum; The evolution and classification of Palms: 1-732. Kew Publishing, Royal Botanic Gardens, Kew.
  • 2 J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008

 Information From

Palmweb - Palms of the World Online
http://www.palmweb.org
Palmweb 2011. Palmweb: Palms of the World Online. Published on the internet http://www.palmweb.org. Accessed on 21/04/2013
  • A Content licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License
  • B http://creativecommons.org/publicdomain/zero/1.0
eMonocot
http://e-monocot.org
eMonocot. (2010, 1st November). Retrieved Wednesday, 8th February, 2012, from http://e-monocot.org.
  • C Content licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License
World Checklist of Selected Plant Families
http://apps.kew.org/wcsp/
WCSP 2014. 'World Checklist of Selected Plant Families. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; http://apps.kew.org/wcsp/ Retrieved 2011 onwards
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