Ravenea dransfieldii Beentje

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

Conservation

Vulnerable. Population numbers are low at every site. The Ifanadiana population is under threat of destruction.

Vernacular

Anivo (Betsimisaraka-Masoala); Ovotsarorona (Betsimisaraka-Betampona); Lakatra (for stam.) and Lakabolavo (for pist.) (Tanala).

General Description

Medium-sized palm, the trunk 4-7 m, DBH 10.5- 18 cm (diameter near crown 9.5-15 cm); bark pale brown, scars 2.5-6 cm, internodes 4-7 cm; wood black, extremely hard; wounds in bark bleed watery fluid. Base of crown bulbous, 24 cm across. Leaves 11 - 17 in crown, porrect, straight, held on edge in distal half; sheaths open, 45-63 x 15-20 cm, pale or bright green, covered in white or brown tomentum, glabrescent, the margins with reflexed fibre spines; petiole absent; rachis 330-435 cm long, 4.3-13 x 1.2 -6 cm across proximally, 2-2. 8 x 1-1.2 cm in the middle part, here either deeply canaliculate or with a keel c. 5 mm wide, green with scattered brown scales; leaflets dark green, 70-84 on each side of the rachis, the lowermost reflexed or pendulous (and grouped in 3), the rein margin with almost woody dentiform excrescences; other leaflets in one plane or slightly pendulous, pale or dark green, leathery, ramenta lacking, the proximal (65) 95- 120 x 1.3-4.7 cm (and once with the proximal 2 pairs distant by 30 cm from the more distal pairs), median 72-100 x 3-5 cm (interval 3-4 cm), distal 11-37 x 0.5-3 cm, the top pair connate for 1/5, the rachis continuing past the distal pair for > 1 cm; ramenta very few or none; small sinuous transverse veinlets visible in dried material. Staminate inflorescence solitary, erect, c. 126 cm, branched to 2 orders with erect rachillae; peduncle 44-66 cm long, distally 0.5-2.5 x 0.5-1.25 cm; prophyll unknown; peduncular bracts about 42 cm, 52 -66 x 9 cm, 97 - 140 cm, 100- 139 x 8 cm; non-tubular peduncular bract 4.7 – 7. 9 x 0.1 -0.8 cm; rachis 30-50 cm with 1-6 branched and c. 50 unbranched first order branches; rachillae 18-35 cm long, c. 1.3 mm across; pedicels 1.5-3 mm; bracteole 2.3-2.8 mm, connate for 0-1 mm; flowers foetid or sickly scented, cream-coloured becoming grey- brown, becoming hot at anthesis, not abscising but becoming marcescent; petals very quickly deliquescing, leaving included fibres; calyx connate for 1.8-3 mm, 2.3-2.6 mm across, free lobes triangular, acute, 0.8- 1. 7 x 0.8- 1.2 mm; petals free, narrowly ovate, acute, 4.5-6.5 x 1. 5- 2.5 mm; anthers 3 – 3.3 x 1- 1.3 mm, the filaments 0.2 mm (anther inserted 0.5 mm up the petal when antepetalous) to 0.6- 1.6 mm (antesepalous); pistillode 0.3-0.7 x 0.3-0.5 mm. Pistillate inflorescence solitary, interfoliar, branching to one order, erect, largely obscured by the leafsheaths; peduncle c. 26 cm long, proximally 3 x 1. 4 cm, distally 2.5-2.8 x 1. 3 cm across' prophyll 28 x 9 cm, white, membranous; peduncular bracts almost fleshy, pale cream-coloured when fresh, becoming brown, the proximal small (36.5-49 x 3.7-6.5 cm), pubescent externally, glabrous internally, the upper two large, (43 +)-72, (58 +)-74 cm; rachis c. 18 cm long, the rachillae many, tightly packed, appressed-erect, 9- 5-27 cm long, 1.5 - 2 mm across; pedicels 1.5 - 8 mm, with an 80% connate bracteole of 1.5-3.5 mm long; bracteoles 15 x 0.5 cm; flowers foetid or sickly-scented, cream-coloured becoming grey-brown, becoming hot at anthesis, not abcising but becoming marcescent; petals very quickly deliquescing, leaving included fibres; calyx connate for 1 mm, 1 - 5 mm across, free lobes 1-1. 5 x 1.3 mm; petals 4.2-8.5 x 2.3-3.2 mm, c. 1 mm thick; ovary 3.5-4.2 x 2.3-3 mm; staminodes six, 1.5 mm long. Fruit orange (fide Humbert), ovoid or ellipsoid, 15-20 x 12-15 mm, one-seeded; stigmatic remains subbasal; seed ellipsoid, 15 x 10 mm, seed coat black, 0.2 mm thick, with outer sclerified pericarp-like black layer.

Distribution

E Madagascar: between Marojejy Mts. and Ifanadiana.

Biology

Moist forest, on slight to steep slope or hill crest; 425-1700 m. POLLINATION. Flowers visited by beetles (fide Dransfield).