Ravenea hypoleuca

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Ravenea (rah-vehn-EH-ah)
hypoleuca (hypo-leh-OO-kah)
1707e8.jpg
Floribunda Palms, Hawaii. Photo by Geoff Stein
Scientific Classification
Genus: Ravenea (rah-vehn-EH-ah)
Species:
hypoleuca (hypo-leh-OO-kah)
Synonyms
None set.
Native Continent
Africa
Africa.gif
Morphology
Habit: Solitary
Leaf type: Pinnate
Culture
Survivability index
Common names
None.

Habitat and Distribution

Ravenea hypoleuca is endemic to Madagascar. Known only from Vondrozo forest, southeast Madagascar.
Floribunda Palms, Hawaii. Photo by Geoff Stein
Lowland humid forest, valley bottoms or lower slopes; alt. 550 - 600 m.

Description

Medium-sized solitary, dioecious palm. Trunk 6 - 10 m tall, 15 -20 cm in diam., blackish brown, covered in sheath remnants in the upper part, about 25 cm in cross section. Leaves 16 -20 in the crown, porrect, marcescent, litter-trapping; sheath 60 - 110 x 10 - 15 cm, pale green, covered in thick white tomentum, margins disintegrating and fibrous; petiole 80 - 150 cm long, 3.5- 4 x 1.5- 2.5 cm in cross section, deeply channelled, margins sharp, covered in white to greyish tomentum; rachis 3.5- 4 m long, in midleaf 2.5- 2.8 ? x 1.8 -2.3 cm in cross section, pale green, covered in thick white tomentum especially on the abaxial surface, keeled on the adaxial surface; leaflets stiff, regularly arranged in one plane, dark green, 52 - 58 on each side of the rachis, proximal leaflets 62- 85 ? x 1.5-2.8 cm, median leaflets 102- 116 x 2.4- 2.8 cm, distal leaflets 16-37- 1.2 - 2 cm, leaflets spaced 4 . 6 cm apart, abaxial surface with continuous white tomentum, transverse veinlets sinuous. Inflorescences interfoliar, solitary. Staminate inflorescence erect, branched to 2 orders; peduncle 24 . 30 cm long, about 1.5 - 3 cm in cross section, prophyll not seen, peduncular bracts about 73 cm long, about 14 cm wide, purplish, covered in thick white tomentum; rachis about 48 cm long; rachillae 12 - 20 cm long, about 2 mm in cross section; pedicel 0.6 - 1.2 mm. Flowers not seen. Pistillate inflorescence interfoliar, solitary, erect, branched to 1 order, 20 - 30 cm long, about 2.4 cm in cross section; prophyll and peduncular bracts not seen; rachis 10 - 17 cm long; first order branches 18 - 22; rachillae 28 - 42 cm long, up to 1 cm in cross section at the base; pedicel 3 - 5 mm high. Flowers not seen. Fruits not seen. (M. Rakotoarinivo and J. Dransfield. 2010)/Palmweb. Editing by edric.

Initially this was confused with Ravenea albicans because of the strongly discolorous leaflets but it differs in the presence of continuous brown scales on the leaf rachis, rather than striped and discontinuous, and the inflorescence branched to 2 orders in the staminate plants. Based on incomplete material, the palm is nevertheless distinct and should be searched for in good fertile state and also elsewhere. The species epithet reflects the discolorous leaflets. (M. Rakotoarinivo and J. Dransfield. 2010)/Palmweb.

Culture

Cold Hardiness Zone: 10a

Comments and Curiosities

For many years this palm was incorrectly identified as Ravenea albicans due to the same silver backside to the leaflets that Ravena ablicans displays. This is a dioecious genus.

Conservation: Critically Endangered. Rare species, known only from Vondrozo where fewer than 20 mature individuals have been seen in an Extent of Occurrence of 6.7 km2. Current threats are mostly related to habitat loss and degradation due to timber extraction. (M. Rakotoarinivo and J. Dransfield. 2010)/Palmweb.

This is a tillering palm, it exhibits saxophone style root growth (it has a heel), keep top third of heel above soil elevation!

External Links

References

Phonetic spelling of Latin names by edric.

Special thanks to Geoff Stein, (Palmbob) for his hundreds of photos.

Special thanks to Palmweb.org, Dr. John Dransfield, Dr. Bill Baker & team, for their volumes of information and photos.

Glossary of Palm Terms; Based on the glossary in Dransfield, J., N.W. Uhl, C.B. Asmussen-Lange, W.J. Baker, M.M. Harley & C.E. Lewis. 2008. Genera Palmarum - Evolution and Classification of the Palms. Royal Botanic Gardens, Kew. All images copyright of the artists and photographers (see images for credits).

Rakotoarinivo, M. & Dransfield, J. 2010. New species of Dypsis and Ravenea (Arecaceae) from Madagascar.


Many Special Thanks to Ed Vaile for his long hours of tireless editing and numerous contributions.

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