Dypsis andilamenensis

Dypsis (DIP-sis) andilamenensis (ahn-dil-ah-men-NEN-sis)
Madagascar. Photo by Dr. John Dransfield, Royal Botanic Gardens, Kew/Palmweb.
Scientific Classification
Genus: Dypsis (DIP-sis) Species: andilamenensis (ahn-dil-ah-men-NEN-sis)
Synonyms
None set.
Native Continent
Africa
Morphology
Habit: Clustering Leaf type: Pinnate
Culture
Survivability index
Common names
None.

Habitat and Distribution

Dypsis andilamenensis is endemic to Madagascar.

Andilamena, Madagascar. Photo by Dr. Mijoro Rakotoarinivo/Kew.

Known from a single site in the centre of Madagascar, Andilamena area. Montane forest, with rather open canopy; alt. 750-800 m.

Description

Clustering, climbing palm. Stems to 15 -20 m long, 1.2 - 1.5 cm in diam., flexible, proximally ridged and cracked vertically with lenticels, internodes 20 -25 cm long, bright green near the crown. Leaves 6 -8 in the crown, marcescent; sheath 25 -36 cm long, not forming a crownshaft, pale green, densely covered with white wax, scales scattered in the distal part, auricles to about 3 mm high; petiole absent; rachis 1.2 -1.4 m long, 4- 6 mm wide at the base, tapering to 1 mm distally, triangular but slightly concave on the adaxial face of the proximal part, minutely scaly; leaflets 18 -22 on each side of the rachis, irregularly arranged, dark green to yellowish, coriaceous, lanceolate, pendulous, twisted at the base, inserted at the rachis with a woody pulvinus, basal leaflets grouped in 2s, median arranged singly but irregularly and the distal ones in pairs, proximal leaflets 9- 14 x 1.1- 2.4 cm, median leaflets 17 -21 x 2.8- 3 cm, distal leaflets 6- 9 x 1.4-1.8 cm, leaflet tip 3-10 cm long, leaflet surface glabrous. Inflorescences interfoliar, pendulous, branched to 1 or 2 orders; peduncle 43 - 82 cm long, 0.3 - 1 cm wide at the base, densely covered in red brown tomentum; prophyll inserted 12- 16 cm above the base of peduncle, 19 -28 x 0.7- 1.2 cm, glabrous or minutely scaly, 2-keeled, split to 1 . 2.6 cm in the distal part; peduncular bract deciduous, inserted at 25 . 31 cm from the peduncle base, 24.5-44 ?x 2.6-3.8 cm, with few scattered scales, with a beak about 0.5 cm long; rachis 18- 42 cm, densely covered in red brown indumentum, up to 5 first order branches branched and 10-12 unbranched; rachillae spreading and pendulous, 10- 26 cm long, about 1.5 mm in diam., glabrous to densely scaly. Staminate flowers sepals 0.8- 1.5x 1.1- 1.6 mm, imbricate, unequal, disintegrating at the margins, ciliolate; petals 2.1-2.2x 1.5 -1.6 mm, valvate, striate; stamens 6, biseriate but differing less than 0.2 mm in height, filaments 0.8-1 mm, anthers about 1.1-1.4 mm, medifixed, pistillode minute, 0.6 mm. Pistillate flowers with sepals 1.4-1.5 ?x 1.2-1.5 mm, imbricate, ciliolate; petals 1.8- 2x 0.9 -1.3 mm, valvate, striate; gynoecium about 1.1 x 0.7 mm, ovoid. Fruit ellipsoid, 7.2-8.8 x 3.8-5.1 mm, yellowish, mesocarp fleshy, endocarp fibrous. Seed ellipsoid, acute at the apex, 7.5 - 8.4 x 3.6 -4.2 mm, endosperm deeply ruminate. (M. Rakotoarinivo and J. Dransfield. 2010)/Palmweb. Editing by edric.

In the field this species was mistaken for Dypsis scandens, the only other climbing palm known from Madagascar, but in the herbarium, differences soon became obvious. The ruminate endosperm, (homogeneous in D. scandens) immediately recalled D. nodifera, at the time the only other non-arborescent species in the genus, with ruminate endosperm. Furthermore, the inflorescences of D. andilamenensis are much more robust, and the whole plant dries deep brown rather than paler greenish brown. The species epithet is based on the locality. (M. Rakotoarinivo and J. Dransfield. 2010)/Palmweb.

Culture

Cold Hardiness Zone: 10a

Comments and Curiosities

Conservation: Critically Endangered [CR (B2a+b (iii)]. Known only from a single location where the Extent of Occurrence is estimated to be 4.3 km2. This species is quite abundant in the field but its habitat is not protected and is being cleared. Deforestation and illegal mining for rubies are the threats to Dypsis andilamenensis. (M. Rakotoarinivo and J. Dransfield. 2010)/Palmweb.