Ravenea julietiae

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Ravenea (rah-vehn-EH-ah)
julietiae (jool-ee-eh-TEE-eh)
P1010055Raveneajulietiaephil.jpg
Madagascar. Photo by Phil Arrowsmith.
Scientific Classification
Genus: Ravenea (rah-vehn-EH-ah)
Species:
julietiae (jool-ee-eh-TEE-eh)
Synonyms
None set.
Native Continent
Africa
Africa.gif
Morphology
Habit: Solitary
Leaf type: Pinnate
Culture
Survivability index
Common names
Sindro madiniky (Betsimisaraka, Antanambe); Saroroira (Betsimisaraka, Ampasimanolotra); Vakapasy, Anive, Anivona (Tanala/Antaisaka).

Habitat and Distribution

Endemic to Madagascar. Endemic to east Madagascar occurring between Vangaindrano and Mananara Avaratra.
Masoala Peninsula, Madagascar. Dr. Romer Rabarijaona (curator), Kew, Madagascar Conservation Centre, giving scale. Photo by Dr. William J. Baker, Royal Botanics Garden, Kew.
Moist lowland forest; on slight to steep mid slopes; 50-900 m.

Description

Graceful medium-sized palm. TRUNK 3-10 m high, 10-15 cm in diam., diameter near crown about 7 cm; basal boss to 15 cm high, 40 cm across; internodes 6-12 cm (near crown 2 cm), nodal scars about 1 cm, bark brown-grey; wood very hard, with black fibres just below the bark; base of crown bulbous, about 15 cm across. LEAVES 9-23 in the crown, gracefully arching; sheath 40-80 x 12-16 cm, pale green, the base abaxially with white to pale brown tomentum; petiole 30-80 cm long, proximally 3.5-6 x 2.2-4 cm across, distally 2.5-4 x 1.4-3.5 cm, deeply channelled with sharp edges, glabrescent or with a few scattered scales; rachis 1.1-2.8 m, channelled or flat for some 40 cm, keeled for the rest, green with white scattered scales, in mid-leaf 1.7-2 cm wide; leaflets stiff or with the distal part of the leaflet pendulous, the leaflets on opposite sides of the rachis at an angle of nearly 180° to each other, 34-48 on each side of the rachis, the proximal 58-110 x 1.3-3.7 cm, median 47-90 x 3.3-5.2 cm (interval 4 cm), distal 10-26 x 1.2-2.3 cm, ramenta apparently none, but in young leaves sparse large ramenta over entire length of midrib. STAMINATE INFLORESCENCE interfoliar, only known dead, multiple in 5s-7s, the individual inflorescences up to 90 cm, branched to 2 orders; peduncle 38-47 cm, distally about 5 x 3 mm across; prophyll not seen; peduncular bracts unknown, except for one found on the ground, 84 cm long; rachis 46-55 cm, distally zigzag, with about 26 branched and 5 unbranched branches; rachillae 3.5-17 cm, distally sinuous. PISTILLATE INFLORESCENCE interfoliar, solitary, erect, spreading in fruit, 250-400 cm, branched to 1 order; peduncle 145-305 cm, proximally 2-2.2 x 1.3-1.8 cm across, distally 1.5 x 1 cm across, green with silvery-brown indument; prophyll 15-20 x 5 cm; peduncular bracts 22-36 cm (inserted at 2-6 cm from the base of the peduncle), 37-114 cm (inserted at about 13 cm), 185-225 cm (inserted at about 19 cm), 240-280 cm (inserted at 25-115 cm); rachis 28-70 cm long; rachillae 29-34 in number, 20 (distally) -49 (proximally) cm, 2.5-4 mm across in fruit; pedicels 1-8 mm; flowers unknown. FRUIT colour unknown, ellipsoid, 22-27 x 17-20 mm and with lateral beak in younger stage, one-seeded. SEED ovoid or ellipsoid, black, 19-20 x 14-17 mm; seedcoat black, 0.2 mm thick. GERMINATION remote; eophyll bifid. (J. Dransfield and H. Beentje. 1995)/Palmweb. Editing by edric.

The staminate trees seem to have more leaves than the pistillate, with ranges from 21-23 (staminate) and 11-19 (pistillate). Male trees also seem to have longer petioles, 60-80 cm rather than 30-50 cm. The species is distinguished from other species with solitary pistillate, but multiple staminate inflorescences, by its extraordinarily long pistillate inflorescences, its large black seeds, and the dimensions of its leaflets. It is the only Ravenea species apart from R. louvelii in which remote germination has been observed, rather than the usual adjacentligular germination. (J. Dransfield and H. Beentje. 1995)/Palmweb.

Culture

Cold Hardiness Zone: 10a

Comments and Curiosities

This is a dioecious genus.

A graceful palm of lowland forest. The female inflorescences are unique in that they are longer than the leaves, but the male trees are quite like R. sambiranensis. The species is named for HB's wife Juliet, who first pointed it out in the field.

Conservation: Endangered. Ravenea julietiae is known from six widely separated sites (locations) in the east of Madagascar but the number of individuals is always low at each locality and the whole population of this species is estimated to consist of about 80 mature trees. The extent of occurrence is over 34,000 km² but the area of occupancy is quite restricted at 112 km². There is continuing decline in the quality and extant of the habitat and in mature individuals due to the impacts of harvesting. The species therefore meets the requirements for a Vulnerable listing under criterion B2 and D1.Numbers are very low (less than 80 trees seen). Both southern localities (where the bulk of the population occurs) are being destroyed rapidly. The main threats to this species are habitat loss through clearance for shifting agriculture and logging and felling of the palm for its trunk which is used as construction material. (Rakotoarinivo, M. & Dransfield, J. 2012)

Uses: The trunks are used in house construction, and hollowed trunks are used for irrigation pipes.

A rare palm from only a few localities along the east coast of Madagascar, where it grows in lowland rainforests. It produces a fairly slender trunk, topped by a crown of keeled and distinctly arching leaves. Similar to Ravenea sambiranensis, it is distinguished by its long inflorescences and much larger fruits. (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!



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).

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.

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