Ravenea xerophila
Ravenea (rah-vehn-EH-ah) xerophila (zehr-oh-FILL-ah) | |||||||
---|---|---|---|---|---|---|---|
Madagascar. Photo by ally | |||||||
Scientific Classification | |||||||
| |||||||
Synonyms | |||||||
| |||||||
Native Continent | |||||||
| |||||||
Morphology | |||||||
| |||||||
Culture | |||||||
| |||||||
Survivability index | |||||||
| |||||||
Common names | |||||||
|
Contents
Habitat and Distribution
Endemic to South Madagascar, between Ampanihy and the Ampingaratra Mts. Occurs in dry spiny Didiereaceae/Euphorbia bush or dry low forest, on laterite or gneiss. May grow in groups. Recorded at low elevations from 100 up to 700 m.Description
Solitary medium-sized palm. TRUNK 1.5-8 m high, 13-30 cm in diam., widened at the very base; distal half of trunk (or in smaller trees the entire trunk) covered in densely packed sheath remnants; near crown about 10 cm in diam.; bark brown; internodes 2.5-8 cm; nodal scars 0.5-1 cm, occasionally with tattered sheath remnants appearing as threads; wood hard; trunk sometimes producing a yellow latex-like substance when slashed. LEAVES (11-) 18-22 per crown, glaucous, gracefully arching, with stiff segments, the old leaves marcescent; sheath 36-55 x 13-20 cm, white- to dark brown tomentose, the tomentum quickly deciduous, the distal part waxy-white; petiole 22-60 cm long, proximally 2.8-6 x 2.0-3.5 cm, distally 1.4-3.0 x 1.4-2 cm, slightly channelled adaxially, with rather sharp edges, proximally red-brown tomentose, distally glabrous and yellow or with whitish bloom when dry, abaxially strongly convex; rachis 1-2.1 m long, in mid-leaf 0.9-2 x 0.8-1.6 cm, pale green with white bloom; leaflets pale green, stiff, coriaceous, the leaflets on opposite sides of the rachis at an angle of less than 90° with each other, slightly glaucous, acuminate, 47-55 on each side of the rachis, regular, coriaceous, glaucous, the proximal ones 33-110 x 0.3-1.5 cm, median 43-64 (94) x 1.3-2.4 cm (interval 3.5-4 cm), distal 11-44 x 0.3-1.3 cm, secondary veins very visible, tertiary veins indistinct, ramenta red-brown or grey, elongate, 1-2 (-3) near the base of lower leaflets, to large patches of dense ramenta in the proximal third of the midrib, upper 12 pairs without ramenta.read more |
---|
STAMINATE INFLORESCENCE solitary, 55-58 cm, branched to 1 order; peduncle 15-19 (or more) cm, distally 5 x 3 mm across; prophyll not seen; peduncular bracts seen 31 cm, 41-62 cm, 44-62 cm; rachis 29-40 cm, with c. 100 branches; rachillae 1.5-7.5 cm, 0.6-1 mm across; pedicels c. 0.2 mm long, 0.7 mm across, with a 1-1.3 mm bracteole. STAMINATE FLOWERS with the calyx connate for 0.3 mm, free lobes 1.9 x 0.3 mm; petals 6-7 x 2.4-2.5 mm, connate by the fila-mental callus of the antesepalous stamens; stamens in 2 series, the antesepalous ones with a filamentous callus 0.6 x 0.4 mm, anthers 2 0.9 mm; antepetalous ones adnate to the petals for about 1.1 mm, with no free filament, anthers 1.9-2 x 0.9 mm. PISTILLATE INFLORESCENCE solitary, 60-80 (or more) cm, branched to 1 order; peduncle 36-40 cm, proximally 8-13 mm across, 6-13 x 3-9 mm across distally, usually with whitish bloom, occasionally puberulous, glabrescent; prophyll not seen; peduncular bracts white to brown- pubescent, (in bud 15, 21, 20-32 x 1 cm, 31-40 x 1 cm), densely white-tomentose, more brown distally, the most distal one inserted at 21 cm from the base of the peduncle; rachis 20-35 cm long; rachillae porrect, 22-41 in number, 5-33 cm long, 1-2.2 mm across, with slightly bulbous base, proximally 4-7 x 2-5 mm, sinuous, more distally zigzag, with spaced flowers; pedicels 0.5-8 mm long. PISTILLATE FLOWERS with the calyx connate for 0.9-1.2 mm, with free lobes 1-1.3 mm; petals 4-6 x 1.5 mm, narrowly triangular, acute; staminodes 1.7 mm; ovary broadly ovoid to conical, 2 mm. FRUIT 15-22 x 17-27 mm, yellowish, 1-, 2- or 3-seeded, 20-26 mm across in 1seeded fruit, lobed in the more-seeded ones and then 22-23 x 22-34 mm; stigmatic remains subapical to lateral; endocarp slightly sclerified, loose and rather thin. SEED 16-18 x 12-18 mm, globose, hemispherical or in the shape of a third of a sphere, yellow-brown, with white endosperm with small central lacuna. (J. Dransfield and H. Beentje. 1995)/Palmweb. Editing by edric.
The Humbert collections are from a different habitat than the other collections (i.e. dry forest) and, in some instances, have larger leaflets, longer rachillae and smaller fruits. The protologue mentions an epi- phytic orchid found associated with this palm; HB believes the same orchid grows in the population he visited, where it seemed restricted to the leaf sheaths of this palm. It is probably a species of Cymbidiella (D. Du Puy, pers. comm.) |
Culture
Full sun, and very well drained. Does seem to be able to take quite a lot of water, as long as the drainage is good. Quite a slow grower.
This plant develops a very vigorous root system of fleshy white roots, wher it stores up water for dry times.
Comments and Curiosities
read more |
---|
This is a dioecious genus. One of the rarest Ravenea species. This would probably be an excellent species for cultivation, as it grows in very dry sites, and is an extraordinarily beautiful palm. The Latin name means "dry-loving". (J. Dransfield and H. Beentje. 1995). Conservation: It is classified as The IUCN Red List of Threatened Species 2012: Vulnerable. Endemic palm of the sub-arid zone between Ampanihy and the west of Andohahela, this species is known from four scattered sites where about 450 trees are estimated in total. The species has an extent of occurrence of 17,191 km² and an area of occupancy of 676 km². The habitat is decreasing following habitat conversion (charcoal production and livestock) and is threatened by the increasing frequency of fires in this area. The species meets the requirements for listing as Vulnerable. The dry habitat is rapidly being cleared for the production of charcoal, the extent and quality of the habitat is also impacted by the increasing frequency of fires and browsing by nomadic livestock. The dry habitat is rapidly being cleared for the production of charcoal, the extent and quality of the habitat is also impacted by the increasing frequency of fires and browsing by nomadic livestock. Protected in Andohahela. (Rakotoarinivo, M. & Dransfield, J. 2012.) Uses: Local people collect the palm’s leaflets by hand in order to weave mats, trays, and baskets. The leaves of Ravenea xerophila Jum. (anivona palm), a dioecious palm with a solitary trunk up to 8 m tall, occurring in dry forest in southern Madagascar, are used to weave hats and winnowing baskets. The species is one of the most drought tolerant palms of Madagascar. It is classified as The IUCN Red List of Threatened Species 2012:, as it occurs in low numbers in only 2 locations, one of which is being destroyed by overgrazing. Outside Madagascar Ravenea xerophila is grown as an ornamental. I have two 10 year old seedlings... one in the artic lawn where temps were probably pretty low (27 F is the lowest I recorded, but this seedling is near a Trachycarpus latisectus that was defoliated, and a Trachycarpus martianus that was scorched significantlly)... one leaf did fold in on itself. Later this leaf was lost, as was one other. This plant has had frost on it 4x now this winter with no damage at all, but temps were not even 32F those nights. There was no frost at all this night. Turns out, from how things did in neighboring yards and from what little actual data was taken near me, that the edge of my yard may have gotten down to 24 F... this palm is in the lowest spot at that edge. Got more frost a month later and still looks great. This is my vote for the hardiest of all the Raveneas! (Geoff Stein) One of the strangest of all palms, this species from the arid regions of S-Madagascar develops a large, water-storing root system. With its grey, V-shaped and recurving leaves it has some resemblance to species of Butia. John Dransfield and Henk Beentje in their comprehensive “The Palms of Madagascar” write: “One of the rarest Ravenea species. This would probably be an excellent species for cultivation, as it grows in very dry sites, and is an extraordinarily beautiful palm. The latin name means ‘dry-loving.’” In a well drained soil it will grow in warm temperate as well as in tropical regions. (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
- Glossary of Palm Terms
- MODERN BOTANICAL LATIN
- "Just To Be Clear"
- 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).
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.