| Ravenea (rah-vehn-EH-ah) |
Mt. Warning Caldera, Nth. NSW, Australia. Photo by Pete.
Habitat and DistributionNorth West, East and South East Madagascar, from Manongarivo to Marojejy, and south to Andohahela.
Widespread in the forests of the central and eastern escarpment of Madagascar occurring from Taolagnaro to Daraina (eol.org)
A majestic palm. TRUNK 12-30 m high, columnar or slightly ventricose, 20-60 cm. in diam. at breast height, increasing to 75 cm, decreasing to 16-40 cm near crown; base bulbous, 15-50 cm high, 47-100 cm across, with surface roots to 30 cm long, 6-12 mm across, with minute adventituous side roots; outer wood hard, heartwood white and soft; leaf scars obscure, 3-7 cm; internodes 7-25 cm (near crown 4-5 cm); bark pale brown, pale reddish or grey, closely fissured to smooth. Distal part of trunk usually with remnants of sheaths. Wood extremely hard on the outside, due to many black fibres; heartwood soft, white. LEAVES 11-25 in the crown, spiral, porrect, held in shuttlecock, straight or nearly so, often held on edge in the distal part of the leaf; leaflets stiff or curved downwards in the proximal part of the leaf; sheath grading smoothly into the petiole, ligules present or absent, about (38-) 50-112 cm, 16-45 cm wide, bulbous or not, abaxially densely white- to grey-brown tomentose, later glabrescent, adaxially pale orange, with some stiff reflexed marginal fibres 1.5-2.5 mm across; petiole 17-134 cm, proximally 8-17 x 2-4 cm, distally 3.8-8 x 1.3-4.5 cm, channelled with sharp edges or slightly convex adaxially, convex abaxially, thickly grey-brown tomentose, glabrescent; rachis 2.2-4 m, in mid-leaf 1-4.7 cm high, 1.7-3.3 cm wide, medially sharply keeled or flat (on same tree!), abaxially with grey indument but quickly glabrescent; leaflets regular, in one plane or those at opposite sides of the rachis at a slight (up to 120°) upwards angle, dark green, (40-) 50-105 on each side of the rachis, the proximal (19-) 45-120 x 1-4 cm, median 60-126 x 2.5-7.5 cm (interval 2-5 cm), distal 13-46 x 0.3-3.5 cm, top pair often connate for up to 5 cm, ramenta large, many in young leaves, a few proximal ones in older leaves, deciduous, 1-6 main veins. STAMINATE INFLORESCENCE solitary, erect, interfoliar or infrafoliar among dead leaf bases, branching to 2 (-3 in Humbert 6232) orders; peduncle 50-60 cm, proximally 2.8-3.3 x 2.5 cm, distally 2.2-2.8 x 1.3-2 cm, densely pubescent; prophyll 13-47 cm; 1st peduncular bract 18-77 R AVENEA x 8 cm (inserted at 3-11 cm from the base of the peduncle), 2nd (39-) 109-160 x 10 cm (inserted at 5 cm), 3rd 166-209 x 15.5 cm (inserted at 13 cm), 4th 175-209 cm (inserted at ?), all bracts abaxially with thick pale or red-brown tomentum; non-tubular peduncular bract about 19 x 1 cm; rachis 84-131 cm long, proximally pubescent, distally glabrous, yellowish; proximal rachis bract 4-19 x 0.8-2.4 cm; rachillae many (in the lowland population with 60-140 branched and 39 unbranched first order branches), distally densely packed, porrect, straw-yellow, straight or distally sinuous, (5-) 10-47 cm, 1.5-2 mm across; pedicels quite closely set, 0.2-3 mm long; bracteoles 0.7-1 mm long; calyx with connate part 0.8-1.8 mm long and 1.4-2.2 mm across, and free sepals 0.9-1.5 mm long and 1.2-1.8 mm wide, triangular, acute; petals ovate, acute, 1.4-5 x 1.2-2.2 mm, not connate or very briefly connate by the filaments; filaments of all 6 stamens equal, 0.5-1 mm, not or only slightly attached to the petals; anthers 1.5-2.8 x 0.7-1.3 mm; pistillode 0.6-0.8 mm. PISTILLATE INFLORESCENCE interfoliar, solitary, erect, spreading or pendulous in fruit, all axes orange in fruit, branched to 1 order (to 2 orders in Beentje 4600); peduncle 45-100 cm, proximally 3-4.5 x 2.3-2.5 cm, distally 1.2-3.5 x 0.9-2.8 cm, pale green, proximally densely grey-white pubescent, distally glabrescent; prophyll 16-22 x 9-10 cm; peduncular bracts 21-40 x 9 cm (inserted at 5-20 cm from the base of the peduncle), 50-70 x 5-6 cm (inserted at 10-24 cm), 90-120 x 5-6 cm (inserted at about 27 cm), 70-150 x 5-6 cm (inserted at 30-70 cm), all grey-brown tomentose abaxially; rachis 55-80 cm, with 45-100 spreading or reflexed rachillae; proximal rachis bract about 32 x 2.2 cm; rachillae pale waxy green to orange (in fruit), 9-81 cm, 3-4 mm across, distally sinuous, proximally with bulbous bases, 1.2-2.4 x 1.2-1.8 cm, glabrous; pedicels 1-28 mm; bracteole 0.7-1.2 x 0.5-0.6 mm, connate for 0.8-6 mm; calyx connate for 0.8-2.2 mm, 2-3.5 mm across, free lobes 1.5-2.2 x 1.4-2.5 mm; petals (1.6) 4-4.2 x 1.8-2.4 mm; staminodes 0.8 mm; ovary about 3.5 mm. FRUIT orange, obovoid to ovoid-globose, 10-18 x 8-15 mm; usually one-seeded, then stigmatic remains subbasal; occasionally 2-3-seeded, then stigmatic remains terminal. SEED red-brown, hard, 9-16 x 6-13 mm; seedcoat brown, 0.2 mm thick. EOPHYLL bifid. (J. Dransfield and H. Beentje. 1995)/Palmweb. Editing by edric.
Large palm with trunk (6–)12–30 m tall, 20–60 cm in diameter at breast height, base bulbous, 50–100 cm across. Leaves 11–25 in crown, pinnately compound; sheath grading smoothly into the petiole; petiole up to 135 cm long, channelled with sharp edges, thickly grey-brown tomentose; rachis up to 4 m long; leaflets (40–)50–105 on each side of the rachis, stiff, dark green, median leaflets 60–125 cm × 5.5–7.5 cm at intervals of 2–5 cm, top pair often connate for up to 5 cm. Inflorescence unisexual, solitary; male inflorescence branching to 2 orders, peduncle 50–60 cm long, bracts 6, rachis 85–130 cm long, yellowish, with 60–140 branches up to 50 cm long, straw-yellow; female inflorescence spreading or pendulous in fruit, branched to 1 order, peduncle 45–100 cm long, bracts 6, rachis 55–80 cm long, with 45–100 branches up to 80 cm long, waxy green to orange when in fruit. Fruit an orange, obovoid to ovoid-globose drupe 1–2 cm × 1–1.5 cm, 1 (–3)-seeded. Seed 9–16 mm × 6–13 mm, red-brown, hard. (PROTA)
A population found near Sahasinaka growing in the open, may flower when trunks are as short as 6-8 m, but the only other differences with the rest of the populations are the cylindrical trunks, the rather long and wide leaflets (up to 7.5 cm wide, rather than up to 6 cm wide) and the rather long staminate rachillae, and the large seed (13-16 x 11-13 mm, rather than 9-13 x 6-11 mm). The more typical form of R. robustior was seen to grow in the same forest patch, and we feel uncertain about the taxonomic status of the form, which looks different, has a different local name, but in herbarium specimens is almost indistinguishable from typical robustior. Beentje 4686 from the Anjanaharibe Mts. is quite similar to the Sahasinaka population, and also grows in the open. (J. Dransfield and H. Beentje. 1995)/Palmweb.
"Ravenea krociana and robustior are very very similar and sometimes wrongly tagged in Botanic gardens etc, the stand out difference is that Robustiors leaflets are "thinner" and having grown/growing both Krokiana is a faster grower than Robustior." (Pete)
Comments and Curiosities
This is a dioecious genus.
Formerly used to make salt from the ash of the trunk, bitter and not much liked; young leaves used to make brooms; outer wood used for floor- One of the most majestic of Madagascar palms, with boards, tables and house walls. its slightly ventricose trunk reaching into the canopy. In the the Flora (Jumelle & Perrier 1945) this species was considered to occur in only two sites; our investigations and collecting have shown that it is in fact quite wide-spread, occurring from sea-level up to the mountains. (J. Dransfield and H. Beentje. 1995) /Palmweb.
Conservation: Near Threatened. Though widespread, the species is not common, and the continued cutting for palm-heart and construction wood might move it to the Vulnerable category in the near future. Protected populations are the ones in the Ranomafana National Park, Marojejy and Manongarivo Reserve and at Analamazaotra, though trees of this species are still being cut within the Reserves. (J. Dransfield and H. Beentje. 1995)/Palmweb.
Widespread between Andohahela to Daraina with a very large extent of occurrence and area of occupancy, although the latter (2,200 km²) is close to meeting the threshold for the Vulnerable category. The species is known from a large number of locations (26) and the population is not severely fragmented. Individuals are rarely common and the population size is estimated to comprise about 1,000 mature individuals. There is continuing decline in the quality and extent of habitat and decline in number of mature individuals due to the continuous harvesting of plants for their palm hearts and stems. Based on this information, this species is listed as Near Threatened as it almost qualifies for a threatened listing under criterion B2ab(iii,v). (Rakotoarinivo, M. & Dransfield, J. 2012.)
Management: Ravenea robustior is reported as being cultivated in Madagascar but no further details are known. Seeds, collected from the wild, are offered on the international market for ornamental purposes. The seeds do not seem to be recalcitrant. There are about 1700 seeds per kg and germination takes 1–3 months. (PROTA), edric.
Genetic resources and breeding: The continued cutting for palm heart and construction wood might endanger Ravenea robustior in the near future, although some protected populations exist in nature reserves. Ravenea albicans is ranked ‘endangered’ with only two known locations; Ravenea dransfieldii and Ravenea sambiranensis are both ranked ‘vulnerable’. (PROTA)
Prospects: Ravenea robustior is an important source of food (with high nutritional value) and other useful plant parts for the local population. In view of the increasing scarcity of this palm and the long life cycle, it is important to extend planting activities. Seed should be collected from various provenances for safekeeping of the genetic diversity. (PROTA)
Uses: Palm-heart eaten (though the Chef de Poste at Analamazaotra informs us the palm-heart is rather bitter, and not much liked); formerly used to make salt from the ash of the trunk (fide Perrier); young leaves used to make brooms; outer wood used for floorboards, tables and house walls. (J. Dransfield and H. Beentje. 1995)/Palmweb.
In Madagascar the palm heart of three other Ravenea species is eaten. Ravenea dransfieldii has a bitter palm heart, but it is eaten although some believe it to be poisonous; the leaf fibres are used in hat making. Ravenea sambiranensis has a slightly bitter palm heart, which is eaten cooked with manioc; the fruits are also consumed and the outer wood is suitable for making planks for floorboards. The palm heart of Ravenea albicans is also eaten. The young terminal bud (palm heart) of Ravenea robustior is eaten as a vegetable, but some consider it too bitter. The palms are said to be large enough to feed a whole village. It is reported that the ‘pith’, the central soft part of the trunk, can be eaten as well. Young leaves are used for making brooms, and fully developed leaves are used for thatching. The outer wood is used for making floorboards, tables, house walls; it is said to be termite resistant. In former days salt was extracted from the ash of the trunk pith. Ravenea robustior is also a specialty ornamental. (PROTA)
Properties: There is no specific information on the composition of the palm heart of Ravenea robustior, but probably it is comparable to that of palm heart in general which contains per 100 g raw edible portion: water 69.5 g, energy 481 kJ (115 kcal), protein 2.7 g, fat 0.2 g, carbohydrate 25.6 g, fibre 1.5 g, Ca 18 mg, Mg 10 mg, P 140 mg, Fe 1.7 mg, vitamin A 68 IU, thiamin 0.05 mg, riboflavin 0.18 mg, niacin 0.9 mg, folate 24 mg, ascorbic acid 8 mg (USDA, 2002). The wood is extremely hard on the outside, due to many black fibres. The heartwood is soft and white. (PROTA)
A tall and striking palm from the humid east of Madagascar where it grows in humid forests at low and high elevations. Its stocky trunk can reach 30 m (98 ft.) tall and supports a large, shuttlecock-like crown. In its native habitat it is widespread but by no means common, and endangered through cutting for palm heart and building materials. Still rare in cultivation, R. robustior will adapt to mild subtropical and tropical climates. (RPS.com)
This is a tillering palm, it exhibits saxophone style root growth (it has a heel), keep top third of heel above soil elevation!
- Glossary of Palm Terms
- MODERN BOTANICAL LATIN
- "Just To Be Clear"
- Ravenea robustior specimen Map
- THE SAXOPHONE STYLE ROOT GROWTH (HEEL)
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).
Dransfield, J. & Beentje, H. 1995. The Palms of Madagascar. Royal Botanic Gardens, Kew and The International Palm Society.
Many Special Thanks to Ed Vaile for his long hours of tireless editing and numerous contributions.