| Ravenea (rah-vehn-EH-ah) |
Habitat and DistributionEndemic to South central Madagascar, Mangoky and Onilahy river systems.
DescriptionMajestic palm. TRUNK 5-22 (30?) m high, cylindrical or slightly inflated towards the middle, 36-50 cm in diam., near crown 15-18 cm in diam.; internodes 4-10 cm; wood with tough black fibre layer in the outer part; inner wood soft; bark pale brown-grey (not white, as Fl. Madagascar states!); diameter of base of crown about 22 cm. LEAVES 16-25 in the crown, porrect to pendulous, slightly arching, held on edge in the distal half of the leaf; sheath 30-50 x 15-16 cm, green and proximally with cottony white or grey-brown indument; margins ragged and fibrous; petiole 6-20 cm long, 4-4.5 x 1.5-1.6 cm across, adaxially flat with slightly sharp edges, white-waxy and -scaly; rachis green, white and scaly when young, 1.2-1.7 m long, 1-1.7 cm wide towards the middle, abaxially almost flat or slightly convex, densely pubescent to glabrescent, adaxially flat in the proximal half, more distally keeled with flat top and with the keel almost as wide as the rachis; leaflets regular, in one plane, stiff to pendulous, attenuate, green to slightly yellow, slightly waxy, 70-73 on each side of the rachis, the proximal 20-55 x 0.5-1.7 cm, the median 52-64 x 1.5-3.2 cm (interval about 2 cm), the distal 16-42 x 0.4-1.9 cm, especially abaxially with the veins bearing minute whitish scales, also with a few large brown or grey ramenta on midrib abaxially.
|STAMINATE INFLORESCENCE multiple in 5s-7s (Fl. Mad. says solitary), erect, branched to 2 orders, 86-90 cm; peduncle 32-45 cm, green, proximally 0.9-1.1 cm across and densely pubescent, distally about 0.8 cm across and glabrescent, slightly flattened; prophyll not known; peduncular bracts (based on one collection, cut just above base) 18 cm, 85 cm, 88 cm, 71 cm (the last inserted at 13 cm from the base of the peduncle), abaxially short-pubescent; non-tubular peduncular bract at 15-30 cm from the base, membranous, 35-41 x 2 cm; rachis bracts about 6 x 0.2 cm at the base of the rachis; rachis 52- 89 cm, slightly pubescent; branches 60-100, dense; rachillae 3-21 cm long, sinuous in the distal part; bracteole about 0.7 x 0.4 mm; pedicel 0.5-1 mm long. STAMINATE FLOWERS with the calyx connate for 0.5-0.7 mm, 0.6-1 mm across, free lobes 1.2-1.3 x 0.7-0.8 mm, triangular, acute; petals 3.5-5.8 mm, ovate, acute; filaments 0.4 (epipetalous, adnate for 0.3- 0.4 mm)-0.8 (free) mm; anthers 3.1-3.4 x 1.2-1.5 mm; pistillode 0.5 x 0.6 mm. FLOWERS with slight resinous smell. PISTILLATE INFLORESCENCES solitary, erect or spreading, branched to 1 order, 130-150 cm long; peduncle 40-60 cm, proximally 4 x 2.5 cm across, distally 1.2-2.2 x 1-1.8 cm across, green, white-scaly; prophyll 13-16 cm long, adnate for about 2 cm; bracts narrow, 24-35 x 5-7 cm, 52-65 x 6 (inserted at about 4 cm from the base of the peduncle), 110-130 x 5 (inserted at about 5 cm), 124-150 x 4.5 cm (inserted at about 6 cm), abaxially white-scaly; at about 60 cm from the base with a non-tubular peduncular bract about 20 x 0.7 cm; proximal rachis bract 6-15 x 0.3 cm; rachis 50-72 cm, with 125-146 densely packed reflexed rachillae; rachillae 10-32 cm, 1.5 (-2.5 in fruit) mm across, with bulbous base, proximally 3.5 mm across, green with white bloom; pedicel 1-4 mm long. PISTILLATE FLOWER with the calyx connate for 1-1.3 mm, free lobes 1-1.3 x 1.3 mm, triangular, acute; petals ovate/triangular, acute, 3-3.5 x 2.5 mm; staminodes 6, short; ovary ovoid-conical, slightly shorter than the petals. FRUITS bright red, globose to slightly ellipsoid, 7.5-9 x 7-8.5 mm, 1-seeded, with bitter pulp; stigmatic remains subapical to lateral. SEED 5.5-6 x 5.5 mm. SEEDLING with 2 scale leaves and a bifid eophyll. (J. Dransfield and H. Beentje. 1995)/Palmweb. Editing by edric.
The protologue mentions two populations, at Imaloto at the foot of the Isalo and at the Matitina R. near the sea (E Madagascar); the first one must have been the Perrier collection chosen as lectotype (which has staminate and pistillate flowers, as well as young fruit, just as in the protologue); the second one is only cited as Perrier s.n. in the Flore de Madagascar, a specimen which we have not seen; this might be an early collection of R. musicalis, the only eastern species looking vaguely like R. rivularis. HB has searched for palms at the site indicated, but failed to find a single (wild) one; older people did not know of any native palms, nor did they recognize the local name given (Akoraka in the Tanala language). Jumelle (1927b) mentions populations seen on Makay sandstone, in the Mangoky basin; the Flore de Madagascar adds the Sakeny R. valley (Menabe) and Madiovalo, just West of Ambato-Boeni, near the mouth of the Betsiboka R.; and the Bongolava (without mentioning which one; the name just means long plateau and there are several). The first three sites are indicated on the map by question marks. We consider the Madiovalo and Bongolava ones as unlikely; possibly these refer to riverside trees of R. sambiranensis, which has been collected in such a habitat on the (Miandrivazo) Bongolava. (J. Dransfield and H. Beentje. 1995)/Palmweb.
Majesty Palms will grow well outside in Southern California under certain conditions.
First, LOTS of water. And, any conditions that help same. Clay soil is much better than sand, or silt, because clay holds water. R. rivularis like to be waterlogged, since their habitat is along riverbeds.
Make sure to give space to a palm that will produce a trunk a foot and a half (18" or .5 m) across, up to 100 feet (eventually) 33. m tall. A great lawn palm. A great palm in a boggy spot where the land has been raped, and drainage is not so good.
"This is one of the most commonly sold 'house palms' nowadays, and the sad thing is it performs terribly as one. It is a great outdoor plant, though in the continental US it's a bit hard to keep from yellowing at the tips, especially if planted in full sun. It is a relatively fast palm for Southern California, and grows faster the more heat and water it gets. It eventually grows to 50' or more in the US, but in Madagascar, it's home, it can get up to nearly 100'. As the name suggests, it grows along rivers and loves to have its roots constantly moist. The only major dangers to this palm are cold (can't handle temps below the mid 20sF) and snails LOVE it, and will quickly shred the leaves to bits. Watering the crown, particulaly in the cooler months of the year, and especially the cool months to warm month period, is risky (though rain water seems to be OK... tap water is the problem). Rot/bud damage is very common in this species, at it is in many of the non-crownshafted feather-leaf palms, from tap water on the crowns ANY time of the year... but mostly in late winter/spring, as the palm starts to grow again... so if you plant this palm in your lawn, try to avoid having the sprinkler hit the crown. It is nearly impossible to overwater the roots of this plant (unless maybe planted in a very heavy clay soil)... but the crown is very sensitive to being 'overwatered'. I can't tell you how often i see this happen around southern California (and happened to several of my own palms)... live and learn." (Geoff Stein)
Comments and Curiosities
This is a dioecious genus.
An aptly named species, since it only grows along riverbanks. It has recently become very popular in cultivation, and when well-watered grows at an impressive speed. The species can be admired from the main road Ihosy-Tulear, in a large stand at Ilkaka village near the Isalo National Park. (J. Dransfield and H. Beentje. 1995)/Palmweb.
Conservation: Vulnerable in habitat. Some 60 trees seen in two populations; they do not grow in any protected area. (J. Dransfield and H. Beentje. 1995)/Palmweb.
Uses: Seeds collected for export. This is one of the most sought after Madagascan palm species in international horticulture. Seed is harvested from the wild for trade.
Date Assessed: 2010-12-17. ♦ Estimated area of occupancy (AOO) - km2: 144 ♦ Number of Locations: 4 ♦ Lower elevation limit (metres): 300 ♦ Upper elevation limit (metres): 1000
Conservation Actions: The species is listed on CITES Appendix II. The subpopulation at Isalo is on the margin of the national park and those in Analavelona occur in a taboo area. Monitoring of the harvesting is required and possible additional enforcement of the controls. (Rakotoarinivo, M. & Dransfield, J. 2012.)
One of the most popular potted plants on Earth. Fast from seed to a couple meters tall.
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"
- 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.