Orania ravaka Beentje, Palms Madagascar : 119 (1995)

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Content

Introduction

The name 'ravaka' is the Malagasy for ornament, jewel; this is a particularly elegant tree, rather like O. trispatha, but with a more slender trunk. (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A

Distribution

Map uses TDWG level 3 distributions (https://github.com/tdwg/wgsrpd)

Madagascar present (World Checklist of Arecaceae)C

NE Madagascar. (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A

Madagascar, mostly in the eastern part of the island facing the Indian Ocean and on the north coast. Dransfield & Beentje (1995) reported the presence of the species on Île Sainte Marie, an island just off the northeast coast of mainland Madagascar, but no specimen has been collected so far. (A.P. Keim & Dransfield, J. 2012: A monograph of the genus Orania (Arecaceae: Oranieae). – Kew Bulletin 67: 127-190)B

Habitat

Varying from lowland up to rather highland tropical rainforest from about 80 up to 550 m above sea level. (A.P. Keim & Dransfield, J. 2012: A monograph of the genus Orania (Arecaceae: Oranieae). – Kew Bulletin 67: 127-190)B

Discussion

Differs from the other Madagascar species in the inflorescence branched to 2 orders, and from the other distichous species by the fewer leaflets which are smaller (with red-brown rather than grey ramenta), and the longer, more slender inflorescence. (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A
Orania ravaka is the most recently recognised species from the genus Orania in Madagascar (see Dransfield & Beentje 1995). (A.P. Keim & Dransfield, J. 2012: A monograph of the genus Orania (Arecaceae: Oranieae). – Kew Bulletin 67: 127-190)B

Diagnosis

Palma disticha foliolis ramentas castaneas infra ferentis a ceteris speciebus Madagascariensibus inflorescentia in 2 ordines ramificanti et a O. trispatha foliolis paucioribus minoribus et inflorescentia longiore graciliore differt. (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A

Biology And Ecology

Lowland rain forest; ridge crests and valley bottoms; 200-550 m. (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A

Conservation

Vulnerable. Known only from three sites, but with fairly large population numbers, though outside the protected area; total number estimated at 500. (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A
Vulnerable (VU D1, D2) (M. Rakotoarinivo pers. comm.). Orania ravaka has a restricted distribution in Madagascar and an estimated population size of fewer than 800 individuals with an extent of occurrence of 8913 km2 and area of occupancy 220 km2. Some of its localities are within protected areas. (A.P. Keim & Dransfield, J. 2012: A monograph of the genus Orania (Arecaceae: Oranieae). – Kew Bulletin 67: 127-190)B

Etymology

Jewel in Malagasy language of Betsimisaraka dialect. (A.P. Keim & Dransfield, J. 2012: A monograph of the genus Orania (Arecaceae: Oranieae). – Kew Bulletin 67: 127-190)B

Common Name

Sindro (Betsimisaraka); Vapakafotsy (Tsimihety). (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A
Menavozona (Hiaraka), sindro (Sahavary), vapaka fotsy (Betsimisaraka). (A.P. Keim & Dransfield, J. 2012: A monograph of the genus Orania (Arecaceae: Oranieae). – Kew Bulletin 67: 127-190)B

Uses

Not recorded. (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A
Leaves are used for house thatching and trunk for housing. No information about the use of fruits. (A.P. Keim & Dransfield, J. 2012: A monograph of the genus Orania (Arecaceae: Oranieae). – Kew Bulletin 67: 127-190)B

Description

Solitary palm. TRUNK 10-15 m tall, 9-20 cm diam.; diameter just below crown < 10 cm; internodes 2.5-5 cm long, pale brown or grey-brown; nodal scars obscure; basal boss c. 35 cm diam., with surface roots. LEAVES 6-8 in the crown, distichous; sheath open, 35 cm long, with marginal fibres; apparent petiole 30 cm long, channelled; sheath and apparent petiole combined 65-94 cm long, with patches of dense red-brown or grey scales and wax, distally c. 1.3 x 0.9-1 cm diam.; rachis 1.2-1.8 m long, in mid-leaf 1-2 cm wide, densely scaly, with scattered scales or glabrous; leaflets 33-44 on each side of the rachis, regular, stiff, those on opposite sides of the rachis at an angle of c. 90 with each other, strongly discolorous and much paler abaxially, the proximal 36-87 x 0.4-2.4 cm, the median 47-77.5 x 2.5-4.8 cm (interval 3.5-4.5 cm), the distal 18-45 x 0.4-2.8 cm, distal pair hardly connate, apices obliquely praemorse, main veins 3-5, midrib (and occasionally on other major veins as well) with large red-brown ramenta to 15 mm, with scattered red small scales, with visible sinuous transverse veinlets. INFLORESCENCE interfoliar, branching to 2 orders, spreading, protandrous; peduncle curved, 42-60 cm long, distally 12-18 x 5-12 mm diam., rusty-tomentose; prophyll borne 2.5-13 cm above the base of the peduncle, 16-32 cm long, 3.5-6 cm wide, with patches of red-brown scales; peduncular bract(s) one or two (in the same population), deciduous, inserted at 6.5-14 cm and 16 cm from the base of the peduncle, 43-63.5 cm long, 7-9 cm diam., inflated, beaked; rachis with c. 13 first order branches, these proximally to 17 x 8 mm diam.; rachillae cream at anthesis, 7-40 cm long, 2-4 mm diam., zigzag, with rusty scales; triads distant. STAMINATE FLOWERS cream, not scented; sepals 1.5-2.4 x 2.2-2.8 mm; petals 8-13 x 4-6 mm; stamens 22-27, the filaments 0.7-2.5 mm (connate for up to 0.5 mm) with a bulbous base to 1 mm diam., anthers basifixed, slightly sagittate, equal or slightly unequal, 6.3-7.6 x 1.2-1.3 mm; pistillode not seen. PISTILLATE FLOWERS greenish, with sepals 1-4.5 x 4-5.5 mm; petals 10-15 x 9-11 mm; staminodes 9-12, thread-like; ovary globose, 10-11 mm diam., with c. 1 mm long papillose stigmas. FRUIT yellow or pale brown, slightly obovoid or globose, 4-6 cm diam., with sub-basal stigmatic remains. SEED depressed globose, 2.5-3.8 cm high, 3.2-4.2 cm diam., with fibrous surface; endosperm homogeneous; cotyledonary stalk up to 50 cm long and 6 mm diam. (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A
Large palm. Trunk c. 10 - 20 m tall, grossly swollen at base, c. 10 - 20 cm diam. (dbh), internodes 2.5 - 5 cm, greyish brown, obscurely ringed with scars, bark pale brown. Leaves 6 - 8 in the crown - some old individuals with 9 - 13, distichously arranged, densely covered with red-brown tomentum, c. 2.5 - 4.5 m long; leaf-sheath about 21.5 - 35 cm long, 8.5 - 11 cm wide, margins disintegrating into fibres, in some individuals rarely, adaxial surface with thin red-brown tomentum, wax present, abaxial surface with dense red-brown tomentum and creamy white indumentum, sometimes with greyish white indumentum; petiole c. 30 - 94 cm long, c. 1.7 - 2 cm diam. in the middle, margins disintegrating into fibres; rachis about 198 - 321 cmlong, c. 2 cm diam. in the middle; leaflets elongatelanceolate, regularly arranged leaflets held in one plane, c. 33 - 44 on each side of rachis, leaflets c. 5.5 - 7 cm distant, in the proximal c. 3 cm, c. 50 - 74 cm long, 4 - 5 cm wide, adaxial surface glabrous with white substance scattered, thin red-brown tomentum on basal part and midrib, greyish white indumentums on midrib, midrib robust, other ribs thick, abaxial surface with dense white indumentum and thin redbrown tomentum, midrib robust, other ribs thick; ramenta present, mainly on midrib, sparsely on other ribs, red-brown or dark brown, conspicuous, c. 1 cm long. Inflorescence spreading, c. 100 cm long, branching to 2 orders, robust; prophyll hard, persistent, margins adaxially disintegrating into fibres, c. 26.5 - 32 cm long, 3.5 - 8 cm wide, adaxial surface glabrous, abaxial surface deeply covered with red-brown tomentum; peduncle curved, c. 60 cm long, with dense red-brown tomentum, wax present; peduncular bract one or two, woody, c. 45 - 62 cm long, 9 cm wide, adaxial surface glabrous, abaxial surface deeply covered with redbrown tomentum; rachis c. 40 cm; first order branches 13, c. 4 - 9 cm long each, rachilla bracts minute, in some individuals conspicuous, c. 1.5 cm long, 0.8 cm wide; rachillae robust, c. 26 - 40 cm long each, bearing 54 - 78 flower clusters, triads arranged in the proximal 1=5 part, the basal c. 2.5 - 3.5 cm devoid of flowers, triads c. 1.5 - 3 cm distant, rachilla glabrous, number of triads in rachilla 1 - 3. Staminate flowers with calyx of 3 united minute sepals; corolla creamy white, with 3 free petals, c. 9 - 15 mm long, 3 - 5 mm wide; stamens 16 - 23, filaments free, dark brown, c. 1.25 - 1.5 mm long, anthers elongate-lanceolate, c. 5 - 6 mm long, free, pistillode unknown. Pistillate flowers with calyx of 3 united sepals, 4 mm long; corolla creamy white, with 3 free petals, 10 × 8 mm; staminodes c. 20, c. 3 mm long, uniform; gynoecium c. 8.5 - 9 mm long, 4 mm wide, pale brown, stigma with 3 elongate lobes. Fruit globose or bilobed, c. 4 - 4.5 cm diam., in an individual said to have c. 6 - 8 × 4 cm (Du Puy 152), dull olive green when young, yellowish green when mature, stigmatic remains sub-basal; epicarp smooth, thin, c. 0.7 - 0.8 mm; mesocarp fibrous, c. 2 mm thick; endocarp hard, thinner than epicarp; testa light brown, thinner than endocarp, attached to endosperm; endosperm, creamy white, with c. 3 cm diam., with a hollow inside, c. 8 mm diam. Embryo placed below middle line of seed. Eophyll bifid. (A.P. Keim & Dransfield, J. 2012: A monograph of the genus Orania (Arecaceae: Oranieae). – Kew Bulletin 67: 127-190)B

Materials Examined

Maroantsetra: Hiaraka, Oct. 1986 (fl.), Dransfield et al. JD6376 (K, P, TAN); Sahavary, Oct. 1986 (fl., fr.), Dransfield et al. JD6401 (Holotype K; isotypes P, TAN); idem, Feb. 1988 (y.fr.), Dransfield et al. JD6458 (K, TAN); idem, April 1989 (fr.), Du Puy & Du Puy MB 161 (K, TAN). Mananara Avaratra: Antanambe, Oct. 1991 (fl., fr.), Beentje & Andriampaniry 4466 (BH, K, MO, P, TAN). (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A
Maroantsetra: Masoala Peninsula, west coast, Hiaraka, 11 Oct. 1986, J. Dransfield JD 6376 (K!, TAN); Andranofotsy river, Sahavary, hill E of Andilampananina village, 23 Oct. 1986, J. Dransfield JD 6401 (K! holotype, TAN); Andranofotsy, Sahavary, hill E of village, 11 Feb. 1988, J. Dransfield JD 6458 (K!, TAN); Masoala Peninsula, c. 6 km of village Hiaraka, 21 April 1989, Du Puy 152 (K!, P, TAN); Sahavary, April 1989, Du Puy & Du Puy MB 161 (K!, TAN). Toamasina: Mananara Biosphere Reserve, 10 - 12 km W of Antanambe, 8 Oct. 1991, H. Beentje 4466 (K!, MO, P, TAN); Soanierana-Ivongo, Ambatovaky Resv., 11 Nov. 1999, J. Dransfield JD 7731 (K!, MO, P, TAN); Maroansetra, Makira, Andranomenahely, 14 May 2007, Rakotoarinivo et al. RMJ 338 (K!, MO, P, TAN). (A.P. Keim & Dransfield, J. 2012: A monograph of the genus Orania (Arecaceae: Oranieae). – Kew Bulletin 67: 127-190)B

Bibliography

A. Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar

B. A.P. Keim & Dransfield, J. 2012: A monograph of the genus Orania (Arecaceae: Oranieae). – Kew Bulletin 67: 127-190

C. World Checklist of Arecaceae

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