Ravenea sambiranensis
Ravenea (rah-vehn-EH-ah) sambirinensis (sam-bihr-ih-NEN-sis) | |||||||
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Photo by Christophe Jardinier. | |||||||
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Morphology | |||||||
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Culture | |||||||
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Survivability index | |||||||
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Contents
Habitat and Distribution
North West, West and East Madagascar, Manongarivo to Marojejy and down the East coast to Vangaindrano; outlier in Bemaraha area. Littoral forest on white sand, dense moist forest or dry montane forests, steep slopes, hill crests or on almost level ground; in the West in remnant riverine forest; 1-2000 m. POLLINATION AND DISPERSAL. Flowers visited by bees and small flying beetles (pers. obs.); fruit eaten by Madagascar Blue Pigeon, and defecated seeds germinating well (as did seed from fallen fruit)Description
Slender tall palm. TRUNK 2-30 m. high, 5-29 cm. in diam. (near crown 5-10 cm); basal boss 25-40 cm high, 32-50 cm across, with surface roots; internodes 2-13 (-18) cm (near crown 1-4 cm), nodal scars faint or clear, 2-4 cm; rarely with; sheath remnants present below the living crown; bark soft, pale grey or brown; outer wood with very hard black fibres; heartwood soft, white. Base of crown bulbous, 18-40 cm across. LEAVES 10-28 in the crown, porrect, arching to strongly arching; sheath 12-70 x 10-20 cm, whitish or brown-tomentose externally, in young leaves entire and fibrous, rupturing opposite the petiole when ageing and then the margins with hard fibres; petiole 13.5-76 cm, proximally 1.3-7 x 0.6-4 cm across, convex and white- or brown-grey-pubescent abaxially, slightly convex, flat or concave with sharp edges adaxially, distally 0.9-3 x 0.5-1.6 cm, glabrescent, dull green; rachis 0.6-2.5 m long, in mid-leaf 1.2-3.4 x 1-1.7 cm across, convex and white- to red- or grey-brown-tomentose to puberulous abaxially, glabrescent, adaxially in the proximal part with a channelled keel, more distally with a flattened keel 4-5.5 mm wide, more distal becoming angular and sharp; leaflets rigid, lanceolate, oblique, straight, acute, sometimes pendulous in their distal 1/3 (rarely in one plane), dark green, arcuate, the tips somewhat bent over, 35-67 on each side of the rachis, the proximal 20-78 x 0.2-3.3 cm, median 40-100 x 1.3-4 cm (interval 3.5-5 cm), distal 6-63 x 0.3-2.7 cm, the top pair sometimes connate for up to 2 cm, abaxially on the midrib (and sometimes on the veins) with rather many small ramenta in young leaves-none, or only basal ones in older leaves, main veins 2-7. STAMINATE INFLORESCENCE interfoliar, multiple in 5s-9s, the central ones maturing before the outer ones, erect; individual inflorescences 30-117 cm, branched to 1 or 2 orders; common prophyll membranous, 2.5-23 x 5-12 cm, rounded, tattering, densely tomentose abaxially, glabrous adaxially; peduncle 25-74 cm, 5-9 mm across proximally, distally 3-7 mm across, green, grey-brown tomentose to glabrescent; peduncular bracts respectively 7-35 x 3.2 cm (inserted at 0-0.4 cm from the base of the peduncle), 20-60 x 2-2.2 cm (inserted at 1-2 cm), 56-125 (inserted at about 3 cm), 68-125 x 5.3 cm (inserted at about 7 cm), all white- to grey-brown-tomentose abaxially, adaxially cream, smooth and glabrous; non-tubular peduncular bract 1.5-3.7 x 0.4-0.6 cm, but in Beentje 4501 a non-tubular peduncular bract inserted at 53 cm, 25 x 1.7 cm, membranous, adnate to the peduncle for 21 cm; rachis 20-54 cm, cream, densely pubescent proximally but glabrescent or with flaking patches, with 12-65 branched and 7-38 non-branched first order branches; proximal rachis bract 1.3-20 x 0.6 cm; first order branches at base 3-4 x 2 mm, with 3-6 rachillae; rachillae porrect, 3-23 cm, 1-1.5 mm across, sinuous, cream, with dense flowers above a 2 cm bare base; pedicels 0-1 mm; bracteole 0.7-1.8 x 0.5-0.8 mm, narrowly triangular, acute.read more |
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STAMINATE FLOWERS custard-yellow, scarcely to sweetly scented; calyx with connate part 0.5-1.5 x 1.3-1.8 mm, free sepals 0.9-2.5 x 0.7-1.6 mm, ovate, acute; petals free, 1.8-5 (-6.1) x 2-3 mm, broadly ovate, acute, cream to bright custard yellow; anthers equal, 1-3.7 x 0.8-1.6 mm, filaments equal, 0.3-1.5 mm; ovary rudiment 0.4-2 x 0.3-1 mm. PISTILLATE INFLORESCENCE interfoliar, solitary, erect, 70-175 x about 30 cm, branched to 1 order, with green axes turning orange in fruit; peduncle 29-93 cm, proximally 1.2-5 x 0.6-3 cm across, distally 0.9-2.3 x 0.5-1.5 cm, white- to brown-pubescent, glabrescent; prophyll 5-22 x 9 cm, rounded, tattering, white-pubescent; peduncular bracts 7-34 cm (inserted at 1-4 cm from the base of the peduncle), 23-90 x 4.5 cm (inserted at 2-10 cm), 53-153 cm (inserted at 7-18 cm), 55-155 cm (inserted at 12-43 cm), glabrous and chestnut-brown adaxially, silvery-white pubescent abaxially; non-tubular peduncular bract inserted at 10 cm below rachis, 6-28 x 0.6-0.7 cm; rachis bracts 10-16 x 1.5-2 mm; rachis 14-60 cm, with 28-77 porrect rachillae; rachillae green to pale yellow, 5-50 cm, 1.5-2.5 mm across, with bulbous base 3.5-13 x 3-4 mm and 2 cm bare part, the distal part sinuous; bracteole 1.5-2.8 x 0.6-2 mm, narrowly triangular, acuminate; pedicels 0.3-6 x 1.3 mm (maximum dimensions in fruit only) long. PISTILLATE FLOWERS quite dense, very fragrant, sticky; calyx connate for 0.6-2 mm, 1.3-2.5 mm across, the lobes 0.6-2.6 x 1-2.4 mm, ovate to triangular and acute to acuminate; petals 2.2-5 (-10, Du Puy 807) 1.5-2.3 mm long, (broadly) ovate and acuminate, pale or bright yellow; staminodes c. 1.3 x 0.3 mm; ovary 2.2-3.2 mm high, 1.3-1.8 mm across. FRUIT orange to coral-red, ovoid to oblong, rounded at the apex, 10-12 x 9-10 mm, one-seeded, with lateral stigmatic remains; in Birkinshaw 136 sometimes 2- or 3-lobed (but all fruits in this collection are without seed - though they are orange in colour); fruit often with a high percentage of abortive seed. SEED brown, 7-8 x 5-7.5 mm. EOPHYLL bifid. (J. Dransfield and H. Beentje. 1995) Editing by edric.
There were several problems to be solved around this taxon. The types of R. sambiranensis and R. amara are quite distinct, but with material HB found in the Manongarivo Mountains the distinctions blurred; only the length of the leaf rachis and the number of leaflets is less in the plants from higher altitudes, but all other characters fall within the normal range of variation. Tree size may vary from 6 m (diam. 10 cm) in montane populations, to 25 m (diam. 30 cm) in moist lowland forest. Populations from riverine forest in the dry western Bongolava and the Bemaraha Tsingy, more than 700 km from the main population, show no differences from typical R. sambiranensis. Montane populations from Marojejy differ slightly in a longer petiole, a higher number of leaflets, a longer rachis of the staminate inflorescence; but not enough to warrant distinction even at varietal level. Eastern populations from coastal white sand forest (remnants), as well as from poor soils more inland, differ slightly in the more arching leaves and the slightly longer anthers; all differences are at one end of a range rather than absolute, and therefore we are treating this species as a variable one, rather than distinguishing geographically based subspecies with very minor morphological differences. Beentje et al. 4625 has a hastula-like structure on the leaf rachis. (J. Dransfield and H. Beentje. 1995) |
Culture
Slow growing. Cold Hardiness: USDA zones: 9b
Comments and Curiosities
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This is a dioecious genus. An elegant palm, rather like R. madagascariensis but with curved (rather than straight) leaves. The trees stay small on white sand on the East Coast and in populations on high mountains, but grow to canopy size in high forest on Nosy Be. The name sambiranensis comes from the Sambirano River in NW Madagascar, in which region the species was first found. (J. Dransfield and H. Beentje. 1995). Conservation: Least Concern. Widespread and common in the humid forest between Taolagnaro and Manongarivo, at least 2000 individuals are estimated for all the distribution range. Although there are localized threats in parts of the range, the species is fairly tolerant of this as it sometimes persists in disturbed areas. Given the extensive range, relatively large and increasing population and lack of significant threats this species is listed as Least Concern. Common in lowland humid forest of Madagascar, at least two thousands individuals are estimated for all Madagascar and the population is thought to be increasing. Grows in littoral forest on white sand, in dense moist forest or dry montane forests, on steep slopes, hill crests or on almost level ground; in the west in remnant riverine forest. Has a wide altitudinal range occurring from near sea level up to 2,000 m. Given the huge range of this species there is localized habitat loss through clearance for shifting agriculture and logging in some places, but this does not pose a significant threat. Found in almost all of the eastern protected areas in Madagascar. The species appears to be very tolerant of disturbance. There is also widespread utilization of the species, but this also does not appear to pose a threat. (Rakotoarinivo, M. & Dransfield, J. 2012.) Uses: Outer wood used for floorboards; young palm-heart cooked with manioc and eaten, but slightly bitter (hence Mafahely, which means a little bit bitter). This is a tillering palm, it exhibits saxophone style root growth (it has a heel), keep top third of heel above soil elevation! |
- IMAGE GALLERY
External Links
- Glossary of Palm Terms
- MODERN BOTANICAL LATIN
- "Just To Be Clear"
- http://www.youtube.com/watch?v=ai52JsU5pvg
- THE SAXOPHONE STYLE ROOT GROWTH (HEEL)
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).
J. Dransfield & H. Beentje, The Palms of Madagascar. 1995. The Palms of Madagascar. Royal Botanic Gardens, Kew and The International Palm Society.
Rakotoarinivo, M. & Dransfield, J. 2012.
Many Special Thanks to Ed Vaile for his long hours of tireless editing and numerous contributions.