Dypsis rakotonasoloi Rakotoarin., Palms (1999+). 53(3): 143 (2009)

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Distribution

Map uses TDWG level 3 distributions (https://github.com/tdwg/wgsrpd)
Madagascar native (Palms (1999+). 53: 136 (2009))B
Northeast Madagascar, known from a single locality in the eastern central part of the Makira protected area. (Rakotoarinivo, M., Trudgen, M.S. & Baker, W.J. 2009: The Palms of the Makira Protected Area, Madagascar. – Palms; Journal of the International Palm Society 53(3): 125-146)A

Habitat

  • Primary rain forest, on ridge tops, ca. 900 m. (Rakotoarinivo, M., Trudgen, M.S. & Baker, W.J. 2009: The Palms of the Makira Protected Area, Madagascar. – Palms; Journal of the International Palm Society 53(3): 125-146)A

Discussion

  • As with D. brittiana,, we have only one collection of this species and certain key features such as the nature of the stamens are not known. Nevertheless, it clearly matches no known species and so is here described as new. The species that it most closely resembles appears to be D. fasciculata, but it is an altogether smaller plant and the inflorescence is branched to one order only. We suggest that it belongs to Dypsis Group 15 of Dransfield and Beentje (1995). (Rakotoarinivo, M., Trudgen, M.S. & Baker, W.J. 2009: The Palms of the Makira Protected Area, Madagascar. – Palms; Journal of the International Palm Society 53(3): 125-146)A

Diagnosis

  • D. fasciculatae similis sed habitu minore inflorescentia in 1 ordinem ramificanti differt. (Rakotoarinivo, M., Trudgen, M.S. & Baker, W.J. 2009: The Palms of the Makira Protected Area, Madagascar. – Palms; Journal of the International Palm Society 53(3): 125-146)A

Conservation

  • Critically Endangered [CR (B1a)] (provisional assessment). The justification for this threat category is the same as for D. brittiana (Rakotoarinivo, M., Trudgen, M.S. & Baker, W.J. 2009: The Palms of the Makira Protected Area, Madagascar. – Palms; Journal of the International Palm Society 53(3): 125-146)A

Etymology

  • Dypsis rakotonasoloi is named for Franck Rakotonasolo, botanist at PBZT, who has collaborated with Kew botanists on many adventurous botanical expeditions in Madagascar, providing invaluable logistical support as well as great scientific expertise. Franck discovered this new species with Kew's Adam Britt during their 2005 expedition to Makira. (Rakotoarinivo, M., Trudgen, M.S. & Baker, W.J. 2009: The Palms of the Makira Protected Area, Madagascar. – Palms; Journal of the International Palm Society 53(3): 125-146)A

Description

  • Slender palm. Stems to 2 m, 6-10 mm diam., internodes pale green, more than 1 cm long, scattered black punctiform scales near the crown, nodal scars ca. 1 mm wide. Leaves 5 in the crown, porrect, pinnate; sheath 9-11.5 cm long, open in distal 2.5-3 cm, pale green, densely to sparsely covered with black punctiform scales, auricles ca. 1 mm long; petiole 8-11 cm long, ca. 2 mm wide, scaly, deeply channeled in the adaxial surface; rachis 30-34 cm long, minutely to densely scaly on all surfaces; leaflets 10-14 in each side of the rachis, in group of 2-5 but distal leaflets regular, groups 3-7 cm apart, proximal leaflets 9-11 × 0.5-1.3 cm, median leaflets 11-16 × 1.4-2 cm, distal leaflets 15-17 × 2.8-3.3 cm and multifold, apices unequally acuminate to 3 cm long, main veins 3-5, minute black punctiform on the abaxial surface near the insertion. Inflorescence interfoliar, branched to 1 order; peduncle ca. 30 cm long, distally 1.5-2 mm diam., scaly; prophyll not seen (hidden among the leaf sheath); peduncular bract inserted at ca. 9 cm from the base of the peduncle, ca. 16 × 0.6 cm, pale brown, with few scattered punctiform scales, open in distal 1.7 cm; rachis ca. 6 cm, densely scaly, with ca. 7 branches; rachillae 20-23 cm long, ca. 0.8 mm wide, scaly, triads 0.2-0.5 mm apart. Staminate flowers not seen. Pistillate flowers sepals 0.8-0.9 × 1.1-1.2 mm, triangular, margins ragged, imbricate, minutely scaly; petals ellipsoid, 1.9-2 × 1.6-1.7 mm, striate, valvate; pistil ca. 1.2 × 1.6 mm, stigma ca. 0.3 mm high. Fruit not seen. (Rakotoarinivo, M., Trudgen, M.S. & Baker, W.J. 2009: The Palms of the Makira Protected Area, Madagascar. – Palms; Journal of the International Palm Society 53(3): 125-146)A

Materials Examined

  • Madagascar, Toamasina, Maroantsetra, Makira protected area, Ambinanitelo: Tsaramain-Andro, March 2005, Britt & Rakotonasolo 209 (holotype K, isotype TAN). (Rakotoarinivo, M., Trudgen, M.S. & Baker, W.J. 2009: The Palms of the Makira Protected Area, Madagascar. – Palms; Journal of the International Palm Society 53(3): 125-146)A

Bibliography

    A. Rakotoarinivo, M., Trudgen, M.S. & Baker, W.J. 2009: The Palms of the Makira Protected Area, Madagascar. – Palms; Journal of the International Palm Society 53(3): 125-146
    B. Palms (1999+). 53: 136 (2009)