Ravenea lakatra (PROTA)

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Plant Resources of Tropical Africa
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Ravenea lakatra (Jum.) Beentje


Protologue: Kew Bull. 49(4): 662 (1994).
Family: Arecaceae (Palmae)

Synonyms

  • Louvelia lakatra Jum. (1927).

Vernacular names

  • Ironwood palm (En).
  • Palmier majestueux (Fr).

Origin and geographic distribution

Ravenea lakatra is endemic to Madagascar, where it occurs in the eastern part of the country between Andasibe and Vangaindrano.

Uses

The young leaves are used for weaving high-quality hats. The palm heart is eaten, and the stems are used as irrigation pipes.

Properties

The weaving material from Ravenea lakatra is popular because of its light colour. All woody parts of the palm are very hard.

Botany

Dioecious, medium-sized palm with solitary trunk 4.5–14 m tall and 13–17 cm in diameter at breast height, with a layer of black fibres in the outer part of the stem, the nodes over the whole length of the trunk set with up to 7 cm long woody leaf sheath base remnants; crown shaft absent. Leaves 8–10 in crown, spirally inserted, pinnately compound, slightly arching; sheath 75–80 cm long, with downward-pointing fibres on the margins, densely white-hairy, with black internal fibres; petiole 80–160 cm long, channelled with very sharp edges, with white or grey hairs but glabrescent; rachis 2.5–3.5 m long, with white or grey hairs but glabrescent; leaflets 87–98 on each side of the rachis, in one plane, stiff, medium green, with sinuous transverse veins connecting the longitudinal veins, basal leaflets up to 102 cm long, median leaflets up to 77 cm long, upper leaflets up to 49 cm long. Inflorescence unisexual, solitary, between the leaves, branching to 1 order; male inflorescence with rachis c. 92 cm long, branches up to 30 cm long; female inflorescence erect, peduncle 82–130 cm long, bracts up to 140 cm long, rachis 44–86 cm long, with 50–70 branches up to 65 cm long, white hairy. Flowers unisexual, 3-merous; male flowers with sepals connate for 1 mm, stamens 6, in 2 series, pistillode short, with rudimentary locules and ovules; female flowers with calyx connate for 2–2.5 mm, staminodes 6, with sterile anthers, gynoecium with 3 unilocular carpels, stigmas 3. Fruit a slightly depressed globose drupe 15–20 mm × 18–21 mm, blackish, with terminal stigmatic remains, 1–3-seeded. Seed 9–10 mm × 5–10 mm, black, with distal acumen 1.5 mm long.

In the Manombo region (south-eastern Madagascar) Ravenea lakatra flowers in July–September, and fruits in October–February.

Ravenea comprises 18 species, of which 15 are endemic to Madagascar and 2 endemic to the Comoros. Ravenea lakatra is easily recognized by the woody ‘steps’ (remains of the leaf sheaths) on the trunk, and within the genus it is the only species with acuminate seeds. The leaves of Ravenea xerophila Jum. (anivona palm), a dioecious palm with a solitary trunk up to 8 m tall, occurring in dry forest in southern Madagascar, are used to weave hats and winnowing baskets. The species is one of the most drought tolerant palms of Madagascar. It is classified as endangered in the IUCN Red list of threatened species, as it occurs in low numbers in only 2 locations, one of which is being destroyed by overgrazing. Outside Madagascar Ravenea xerophila is grown as an ornamental.

Ecology

Ravenea lakatra occurs at 100–850 m altitude in moist lowland forest on slopes or ridge crests.

Management

The harvesting of young leaves for weaving prevents the palms from growing, and in practice most populations are pruned to a perpetually juvenile rosette stage.

Genetic resources

Ravenea lakatra is classified as endangered in the IUCN Red list, as it occurs in low numbers in few locations, several of which are being destroyed rapidly. The population at Mantady consists of pruned rosettes only.

Prospects

As Ravenea lakatra is an endangered species, in-situ and ex-situ conservation activities are of the highest importance. In its current area of distribution exploitation of this species should be made sustainable. Introduction into other locations such as botanical gardens and reforestation sites should be encouraged, and supported by research on appropriate propagation and management practices.

Major references

  • Beentje, H.J., 1994. A monograph of Ravenea (Palmae: Ceroxyloideae). Kew Bulletin 49(4): 623–671.
  • Byg, A. & Balslev, H., 2001. Diversity and use of palms in Zahamena, eastern Madagascar. Biodiversity and Conservation 10(6): 951–970.
  • Dransfield, J. & Beentje, H.J., 1995. The palms of Madagascar. Royal Botanic Gardens, Kew and The International Palm Society, United Kingdom. 475 pp.
  • Rakotomalala, M., 2005. Contribution à l’étude de quelques espèces de palmiers endémiques et menacées de Madagascar en vue de leur conservation : cas de Dypsis mananjaranensis (Becc.) Beentje et Dransfield, Dypsis nauseosa (Jum. et H.Perr.) Beentje et Dransfield, Ravenea julietiae Beentje et Ravenea lakatra (Jum.) Beentje dans la forêt dense humide de Manombo (Farafangana). Mémoire de fin d’études, Département des Eaux et Forêts, Ecole Supérieure des Sciences Agronomiques, Université d’Antananarivo, Antananarivo, Madagascar. 65 pp.

Other references

  • Beentje, H.J., 1994. Ravenea in Madagascar. Principes 38(4): 195–203.
  • Byg, A. & Balslev, H., 2003. Palm heart extraction in Zahamena, eastern Madagascar. Palms 47(1): 37–44.
  • Dransfield, J., 1999. Madagascar as a source of new palm introductions. Acta Horticulturae 486: 21–32.
  • Dransfield, J. & Beentje, H.J., 1998. Ravenea lakatra. In: IUCN. 2010 Red list of threatened species. Version 2010.3. [Internet] http://www.iucnredlist.org. October 2010.
  • Dransfield, J. & Beentje, H.J., 1998. Ravenea xerophila. In: IUCN. 2010 Red list of threatened species. Version 2010.3. [Internet] http://www.iucnredlist.org. October 2010.
  • Jumelle, H., 1945. Palmiers (Palmae). Flore de Madagascar et des Comores (plantes vasculaires), famille 30. Imprimerie Officielle, Tananarive, Madagascar. 180 pp.

Author(s)

  • M. Brink, PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article

Brink, M., 2011. Ravenea lakatra (Jum.) Beentje. [Internet] Record from PROTA4U. Brink, M. & Achigan-Dako, E.G. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. <http://www.prota4u.org/search.asp>.

Accessed 8 March 2020.