Dypsis vonitrandambo Rakotoarin. & J.Dransf., Kew Bull. 65(2): 288 (2010)

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Distribution

Northeast Madagascar, known only from Sahamalaza, on the eastern side of the Masoala Peninsula. (M. Rakotoarinivo & Dransfield, J. 2010: New species of Dypsis and Ravenea (Arecaceae) from Madagascar. – Kew Bulletin 65: 279-303)A

Habitat

  • Lowland forest on granite, valley bottom, streamside; 25 m. (M. Rakotoarinivo & Dransfield, J. 2010: New species of Dypsis and Ravenea (Arecaceae) from Madagascar. – Kew Bulletin 65: 279-303)A

Discussion

  • This species belongs to the ??Vonitra? group (Group 16 of Dransfield & Beentje 1995) where the species tend to be very finely differentiated (see Dransfield & Beentje 1995). It is close to Dypsis pusilla but differs by having fewer but strikingly broader leaflets on the rachis, and much more robust inflorescences that bear fewer rachillae. D. pusilla is confined to lowland forest around the Bay of Antongil, from the west coast of the Masoala Peninsula to Antanambe, whereas D. vonitrandambo is restricted to the eastern side of the Masoala Peninsula. The species epithet is based on the vernacular name. (M. Rakotoarinivo & Dransfield, J. 2010: New species of Dypsis and Ravenea (Arecaceae) from Madagascar. – Kew Bulletin 65: 279-303)A

Diagnosis

  • D. pusillae Beentje similis sed foliolis late lanceolatis vice linearibus et inflorescentia robustiore rachillis paucioribus differt (M. Rakotoarinivo & Dransfield, J. 2010: New species of Dypsis and Ravenea (Arecaceae) from Madagascar. – Kew Bulletin 65: 279-303)A

Conservation

  • Vulnerable [VU (D2)], restricted to the eastern part of the Masoala Peninsula and known only from an area less than 10 km2, within the boundary of the National Park. (M. Rakotoarinivo & Dransfield, J. 2010: New species of Dypsis and Ravenea (Arecaceae) from Madagascar. – Kew Bulletin 65: 279-303)A

Description

  • Solitary palm. Trunk to 1 m high, c. 5 cm diam., entirely covered by persistent fibres (piassava) about 5 cm, the fibres large, short, not pendulous; trunk supported by stilt roots to 50 cm above ground. Leaves 7- 10 in the crown; sheaths up to 20 cm long with fibrous margins, not forming a crownshaft; petiole 60- 100 cm long, densely rusty-scaly, adaxially channelled with sharp edges, abaxially ridged; rachis 70 . 90 cm long, in mid-leaf 5.7x 4 mm diam., scaly, strongly keeled; emerging leaflets deep reddish brown, soon becoming green; leaflets regularly arranged, c. 9 on each side of the rachis, bright green, leaflets broad, lanceolate, the proximal 50- 55x 3-3.2 cm, the median 72- 80x 5.5- 7 cm, the distal 12- 27x 1.5- 7 cm, main veins 3 -6, punctiform scales present on the margins and at the leaflet insertion, apices attenuate. Inflorescence interfoliar, erect, emerging from among the fibrous mass of piassava, branched to 1 order; peduncle 65- 80 cm long, proximally 5- 6x 3- 5 mm diam., distally 2- 5x 1.5- 4 mm diam., green, with few scattered reddish scales distally; prophyll not seen; peduncular bract inserted at 25- 40 cm from the base, 30- 45 cm long, pale brown with many patches of dense reddish scales, persistent, with an apical beak 2 . 2.5 cm; rachis 5 . 8 cm long, scaly, with 13-18 branches; rachillae 11-22 cm long, 1 . 2 mm diam., densely scaly, triads distant. Staminate flowers with sepals 0.6- 1 x 0.8 -1.2 mm, asymmetrical; petals 1.4- 1.8 x 0.6- 0.8 mm; stamens 6, biseriate; 3 antesepalous sessile, 3 antepetalous with filaments 0.6 . 0.8 mm long; anthers c. 0.1 x 0.2 mm; pistillode 0.9- 1 x 0.5- 0.7 mm. Pistillate flowers with sepals 0.6-0.8x 0.8- 1 mm, asymmetrical; petals 1.2- 1.4 x 1- 1.2 mm; gynoecium c. 1.2 x 0.6 mm. Fruits young,black, obovoid, c. 6 x 5 mm. (M. Rakotoarinivo & Dransfield, J. 2010: New species of Dypsis and Ravenea (Arecaceae) from Madagascar. – Kew Bulletin 65: 279-303)A

Materials Examined

  • MADAGASCAR. Antsiranana, Antalaha: Masoala Peninsula, Sahamalaza, Iketra, Tanany Rabepierre, 15º45'S, 50 º 12'E, 15 Nov. 1996, J. Dransfield et al. JD 7631 (holotype K!; isotype TAN!). (M. Rakotoarinivo & Dransfield, J. 2010: New species of Dypsis and Ravenea (Arecaceae) from Madagascar. – Kew Bulletin 65: 279-303)A

Bibliography

    A. M. Rakotoarinivo & Dransfield, J. 2010: New species of Dypsis and Ravenea (Arecaceae) from Madagascar. – Kew Bulletin 65: 279-303