| Ravenea (rah-vehn-EH-ah) |
Habitat, Madagascar. Photo by Phil Arrowsmith.
Habitat and DistributionSouth Madagascar, only known from one site. At 0.5-2.5 m depth in flowing water;
Ravenea musicalis is a single-stemmed, evergreen palm tree growing up to 8 metres tall. The unbranched stem can be 30 - 40cm in diameter, it is topped by a crown of 14 - 16 leaves that can be up to 1.8 metres long. (Ken Fern)
Small to medium-sized ventricose palm growing in 0.5-2.5 m deep water. TRUNK 2.5-8 m high, ventricose with base (at water level) to 50 cm across, (above water) 30-40 cm in diam., near the crown about 11 cm across, internodes here 0.5 cm, nodal scars 0.5 cm; bark pale brown, soft, with internodes 1-2 cm; wood soft, cream-coloured, fibrous, without hard fibres. LEAVES 14-16 in the crown, porrect to spreading, arching, held on edge in distal half, with stiff or arching leaflets; sheath 36-41 x 13-20 cm, adaxially orange, abaxially proximally orange, distally green, with thin grey tomentum; fibres few; petiole 15-19 cm long, proximally 3.5-5 x 1.5 across, distally 2.2-2.3 x 0.5-0.6 cm across, glabrous, keeled; rachis 1.3-1.8 m, in mid-leaf 1-1.5 cm across, with little abaxial tomentum; leaflets in one plane, stiff, 59-63 on each side of the rachis, the proximal 36-47 x 0.5-1.5 cm, median 42-53 x 1.6-2.4 cm (interval 2-2.5 cm), distal 10-30 x 0.4-1.3 cm, ramenta none or few, large, basal on midrib and outer main veins, main veins 4. STAMINATE INFLORESCENCE multiple in 5s, the individual inflorescences to 115 cm, branched to 1 order, pendulous in later stage; peduncle 36-38 cm, proximally c. 1 cm across, distally 0.6-0.7 cm across; prophyll 29-30 cm; peduncular bracts 38 cm, 64 cm (inserted at about 2 cm from the base of the peduncle), 84 cm (inserted at about 5 cm), 80 cm (inserted at about 10 cm); rachis about 54 cm, with many dense rachillae; rachillae 7-24 cm, 1-1.5 mm across; flower scars distant. STAMINATE FLOWERS unknown. PISTILLATE INFLORESCENCE solitary, spreading, 105-125 cm, branched to 1 order, the axes green; peduncle 48-52 cm, proximally 3-5 x 2-2.5 cm, distally 2-3 x 1.3-2 cm; prophyll about 10 x 4 cm; peduncular bracts 20-24 cm (inserted at 0 -2.5 cm from the base of the peduncle), 49-52 cm (inserted at 3-3.5 cm), 82-83 cm (inserted at 4-9 cm), 100-103 cm (inserted at 10-24 cm); rachis 39-55 cm, with 58-68 branches; rachillae 9-42 cm, the proximal spreading, the distal porrect, the base proximally flat, 0.6-1.5 x 1 cm, in fruit 3 -3.5 mm across; pedicels c. 0.5 mm. PISTILLATE FLOWERS with the calyx connate for 1 mm, 1.5 mm wide, free lobes 1.7-2.6 x 1.6-2 mm, ovate, acute; petals in fruit only present as fibre remnants, about 2.5 mm long. FRUIT orange, 17-23 x 14-19 mm, one-seeded; stigmatic remnants subapical to lateral. SEED brown, 10-14 mm across, hard, seedcoat black, 0.2 mm thick. SEEDLING with 3-4 scale leaves, the first small, the second, third and fourth to 9 cm long and with curving tips; eophyll pinnate. (J. Dransfield and H. Beentje. 1995)/Palmweb. Editing by edric.
Differs from all other species of Ravenea in its habitat and habit, its extraordinary floating fruit with its spongy mesocarp, splitting at the slightest provocation and then exposing the already germinating seed, the number of its scale leaves on the seedling, and the lack of hard fibres in the outer wood. (J. Dransfield and H. Beentje. 1995)/Palmweb.
"Seeds are hard to come by, and the plant is very difficult to grow, with few plants surviving past the small seedling stage. It needs non-stagnant water, and is very cold sensitive." (Phil Arrowsmith)
"This is one of the few palms that needs to grow in water. Its seeds fall into streams where they germinate and palms remain totally submerged as seedlings until they finally are large enough to pop their crowns out of the water. Madagascan native. Many have tried this in So Cal in their ponds... no luck so far. (Geoff Stein)
Comments and Curiosities
This is a dioecious genus.
Uses: The trunks are sometimes felled for local use to make canoes.
The only true Madagascar water palm, and possibly the only palm in the world of which the seeds sprout under water; fruit and seed are adapted to dispersal by water. The fruits float, but open at the slightest bump; the liberated seed has already sprouted within the fruit, so that when it sinks to the river bottom it can quickly establish itself. The curved scale leaves might even help it to catch onto protuberances, so it would not be washed away easily. The name refers to the musical sound caused by seeds of various sizes dropping from various heights into the river. (J. Dransfield and H. Beentje. 1995)/Palmweb.
Etymology: When the Kew collector climbed one of them to obtain specimens, many fruits fell into the water, making a musical sound. This was why the botanist gave it the scientific name, musicalis.
Conservation: IUCN Red List - Critically Endangered. Endemic to one river to the north of Taolagnaro. Individuals are known from one unprotected locality. The extent of occurrence and area of occupancy are both less than 4 km². The species is relatively abundant with a population of about 450 trees. Plants and seed are harvested for the horticultural trade. Trunks are sometimes felled to make temporary canoes, and there is clearance of the vegetation along the river, which decreases the area of occupancy. Rejuvenation at this site looks good, but as an aquatic species this is very vulnerable to habitat changes. The site is not in a protected area. Urgent conservation action is required for this species. (Rakotoarinivo, M. & Dransfield, J. 2012.)
This species is one of the few palms in the world known to germinate under water, and is adapted to this unusual habitat. The middle layer of the fruit coat is spongy, an adaptation that allows these fruits to float. The seed will germinate within the fruit so that when the fruit splits open (after the slightest bump), it can sink to the river bottom and quickly become established. Unusually, the scale-like leaves produced by the seedling are hook-like and it is thought that these assist the seedling in anchoring itself to the river bottom. (eol.org)
Discovered and described by Henk Beentje in S-Madagascar as recently as 1993, this palm caused a sensation in the palm world as being the only truly aquatic palm. Ravenea musicalis starts its life submerged in shallow flowing water and eventually produces a thick gray trunk topped by an open crown of lax, elegantly arching, pinnate leaves. The problem with collecting the seeds in the past seemed to be that they start germinating while still in the fruit and would rot very soon after collection if uncleaned. (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"
- New aquatic palm by Dr. Henk Beentje, Royal Botanic Gardens, Kew
- 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.