Arecaceae
Ravenea

Ravenea rivularis Jum. & H.Perrier

First published in Ann. Mus. Colon. Marseille, sér. 3, 1: 54 (1913)
This species is accepted
The native range of this species is SW. Madagascar. It is a tree and grows primarily in the seasonally dry tropical biome.

Descriptions

Distribution
S central Madagascar, Mangoky and Onilahy river systems.
Biology
In shallow standing water on riverbanks, swampy valley bottoms, either in deciduous forest or in gallery forest; 350-750 m; gregarious, often forming stands.
General Description
Majestic tree palm. TRUNK 5-22 (30?) m, cylindrical or slightly inflated towards the middle, 36-50 cm diam., near crown 15-18 cm 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 c. 22 cm. LEAVES 16-25, 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 c. 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 c. 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 c. 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 c. 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 c. 2 cm; bracts narrow, 24-35 x 5-7 cm, 52-65 x 6 (inserted at c. 4 cm from the base of the peduncle), 110-130 x 5 (inserted at c. 5 cm), 124-150 x 4.5 cm (inserted at c. 6 cm), abaxially white-scaly; at c. 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.
Conservation
Vulnerable. Some 60 trees seen in two populations; they do not grow in any protected area.
Vernacular
Gora (Sakalava), Bakaly, Vakaka (Bara), Malio (near Manera); majesty palm (in horticulture).
[PW]

IUCN Red List of Threatened Species https://www.iucnredlist.org/species/38677/67737451

Conservation
VU - vulnerable
[IUCN]

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Conservation
Predicted extinction risk: threatened. Confidence: confident
[AERP]

Uses

Use
Seeds collected for export.
[PW]

Sources

  • Angiosperm Extinction Risk Predictions v1

    • Angiosperm Threat Predictions
    • http://creativecommons.org/licenses/by/4.0

  • Herbarium Catalogue Specimens

    • 'The Herbarium Catalogue, Royal Botanic Gardens, Kew. Published on the Internet http://www.kew.org/herbcat [accessed on Day Month Year]'. Please enter the date on which you consulted the system.

  • IUCN Categories

    • IUCN Red List of Threatened Species
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • Kew Backbone Distributions

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0

  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0

  • Palmweb - Palms of the World Online

    • Palmweb 2011. Palmweb: Palms of the World Online. Published on the internet http://www.palmweb.org. Accessed on 21/04/2013
    • Content licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License http://creativecommons.org/licenses/by-nc-sa/3.0