Dypsis ambilaensis J.Dransf., Palms Madagascar : 382 (1995)

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Content

Introduction

  • This is a small palm of the undergrowth of white sand forest developed on raised beaches behind the East Coast. It appears superfically to be almost identical to D. forficifolia. Unfortunately, there are no easy ways to identify the two species, without dissecting the flowers and observing the stamens. However, we have noted that the two species appear to be geographically separated. Ambila-Lemaitso, the type locality, is the root of the species name. (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)B
East Coast, Tampina to Ambila- Lemaitso, south of Toamasina. (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A

Discussion

  • This species is superficially very similar to D. forficifolia and can only be separated with certainty if staminate flowers are available. In D. ambilaensis there are three antepetalous stamens and three staminodes (i.e., this species belongs to the previously recognised Dypsis § Trichodypsis) while in D. forficifolia the stamens are antesepalous and there are no staminodes (i.e., this species belongs to Dypsis § Dypsis). So far, D. ambilaensis has been found only in coastal forest on white sands near Ambila-Lemaitso and Tampina, south of Toamasina. It is particularly confusing that D. forficifolia can grow in an apparently identical forest type along the coast further to the north, near Mananara. A few of the staminate flowers on the specimen Dransfield et al. JD6444 appear to have six fertile stamens (see also Dypsis thermarum). (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A

Diagnosis

  • Habitu foliisque D. forficifoliae superficialiter similis sed floribus staminatis triandris staminibus antepetalis staminodiis antesepalis alternantibus differt. (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A

Biology And Ecology

  • Coastal forest on white sands at low elevation. (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A

Conservation

  • Endangered. Known only from the coastal white sand forests south of Toamasina, forests that are of very limited extent and much prone to damage by fire, as well as to development. (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A

Common Name

  • Not recorded. (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A

Uses

  • Not recorded. (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A

Description

  • Slender, clustering undergrowth palmlet, 1-3 m tall. STEMS c. 5-8 mm diam., internodes 7-18 mm long, green when young, densely covered with caducous dark brown to black scales, old internodes ± blackish. LEAVES c. 7-8 in crown; leaf-sheaths 6-8 x 0.9-1.5 cm, striate, sparsely covered with caducous black scales near base, densely covered distally, leaf sheath mouth with 2 triangular, membranous auricles 3-5 x 3-4 mm; leaf c. 25-40 cm long; petiole absent or to 7 x 0.2-0.4 cm; rachis 15-22 cm long, abaxially covered with blackish scales; blade entire bifid, to 22 x 11 cm, the apical lobes to 13 x 5.5 cm, or divided into 2-4 pairs of narrow to broad, ± sigmoid leaflets, the narrowest at the base, the mid-leaf leaflets usually the broadest, leaflets ranging from 7-20 x 0.5-4 cm, the apical pair (or the two lobes in the entire, bifid leaf) shallowly lobed distally, adaxial surface glabrous, abaxial surface with bands of caducous brown scales, numerous punctiform scales and sometimes with long narrow ramenta along main ribs. INFLORESCENCE interfoliar, only slightly exceeding leaves, branching to 2 orders; prophyll 12-25 x 0.4-0.5 cm, bearing sparse to dense laciniate red-brown scales or glabrescent; peduncle 17-25 x 0.2 cm bearing scattered laciniate dark redbrown scales; peduncular bract exceeding the prophyll by c. 2-6 cm, otherwise similar; rachis 9- 26 cm, sparsely to rather densely covered in red-brown laciniate scales; first order branches 10-27, at least about a half of them branching to the second order; rachillae 16-c. 55, slender, 3-5.5 cm, c. 0.7 mm diam., glabrous, bearing triads c. 2-3 mm distant, each subtended by a low rounded rachilla bract, the bract usually with laciniate redbrown hairs to 1 mm long along margin. STAMINATE FLOWERS at anthesis c. 1 mm diam., red, with slight fecal smell; sepals unequal, broad, imbricate, 0.5 x 0.4-0.7 mm; petals rounded triangular, striate, 0.8 x 0.6 mm; stamens 3, antepetalous, filaments connate at the very base, free portion ± triangular, 0.3 x 0.3 mm, anthers didymous, 0.3 x 0.1 mm, staminodes minute, c. 0.1 x 0.1 mm; pistillode a low dome. PISTILLATE FLOWERS globular, c. 1.1 mm diam.; sepals irregularly rounded, imbricate c. 0.5 x 0.5 mm; petals broadly triangular c. 1 x 1 mm, valvate, imbricate only at the base, striate; staminodes 5-6, irregular, c. 0.15 x 0.1 mm; ovary rounded, c. 1 mm diam., stigmas 3, thread-like, c. 0.15-0.2 mm. Immature FRUIT curved; mature fruit somewhat curved, red, 10-15 x 4.5-5 mm, striate when dry. SEED 8 x 3.5 mm; endosperm homogeneous, embryo lateral, c. 2 mm above base. (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A

Materials Examined

  • Toamasina: Tampina, Forest Reserve near railway, Dec. 1938 (fl.), Lam & Meeuse 6040 (L). Ampasimanolotra: Ambila-Lemaitso, forest west of lagoon on white sand, March 1988 (fl.), Dransfield JD6496 (Holotype K; isotype TAN); Nov. 1986 (fl.), Dransfield JD6444 (K, TAN); idem, Feb. 1924 (fl., fr.), Perrier 16039 (P); idem, May 1928 (fl., fr.), Decary 6480 (P). (Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar)A

Bibliography

    A. Dransfield, J. & Beentje, H. 1995: The Palms of Madagascar
    B. World Checklist of Arecaceae