Dypsis Noronha ex Mart., Hist. Nat. Palm. 3: 180 (1838)

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Content

Distribution

Map uses TDWG level 3 distributions (https://github.com/tdwg/wgsrpd)
Comoros present (World Checklist of Arecaceae)B
Madagascar present (World Checklist of Arecaceae)B
Tanzania present (World Checklist of Arecaceae)B
Approximately 140 species confined to Madagascar, the Comores and the island of Pemba off the coast of Tanzania. At least 20 more are currently undescribed. (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Discussion

  • This is an astonishingly variable genus. Dransfield and Beentje (1995b) found the circumscription of the genera Chrysalidocarpus, Neophloga, Phloga, Vonitra, Antongilia and Neodypsis to be based on highly unreliable characters, and decided to sink them all into the single genus Dypsis. It may well be that after a rigorous phylogeny is produced based on both molecular and morphological characters, the circumscription of groups within Dypsis at the generic level may be possible and desirable.
    (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Diagnosis

  • A complex and highly variable genus of pinnate-leaved palms that has radiated spectacularly in Madagascar and Comores, with an outlier on Pemba off the coast of Tanzania; the genus includes towering forest giants, bottle palms, litter-trappers, stemless palms, some of the most slender of all palms, and even two climbing members; all have fruit with basal stigmatic remains. (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Biology And Ecology

  • The genus displays an extraordinary range of ecological adaptations, occurring from sea level to over 2200 min the mountains, from rain forest to forest transitional with spiny xeromorphic scrub. Many species are palms of the forest canopy whereas others are among the smallest of all palms. Dypsis crinita is a rheophyte, at least as a juvenile, while D.aquatilis grows in relatively deep water, paralleling the remarkable Ravenea musicalis that grows in a nearby river system. (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Common Name

  • For local names and uses see Dransfield and Beentje (1995b). (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Etymology

  • Derivation obscure. (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Uses

  • For local names and uses see Dransfield and Beentje (1995b). (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Description

  • Very small to very large unarmed pleonanthic monoecious palms. Stems solitary or clustered, very short, subterranean, creeping-rhizomatous, erect, in one species climbing, sometimes branched aerially by apparent dichotomy. Leaves pinnate or pinnately ribbed, neatly abscising or marcescent; sheath tubular, rarely almost open, usually forming a well-defined crownshaft, sometimes fibrous, in a few species with abundant pendulous piassava, sheath surface variously scaly and/or waxy or glabrous, auricles sometimes present; petiole absent or short to long, variously glabrous, scaly or hairy; blade entire, entire-bifid, or divided into single or multi-fold reduplicate leaflets, regularly or irregularly arranged, sometimes fanned within groups to produce a plumose appearance, leaflets usually entire, rarely praemorse, very rarely discolourous, often with abundant minute punctiform scales on both surfaces and ramenta along the main rib abaxially. Inflorescences mostly interfoliar, more rarely infrafoliar, spicate or branched to 1–4 orders, apparently protrandrous (?always); peduncle usually elongate, basal branches not sharply divaricate; prophyll often borne above the base of the peduncle; peduncular bract usually conspicuous, exserted and caducous; rachillae variously glabrous or scaly and hairy; rachilla bracts low, generally inconspicuous, sometimes conspicuous; flowers borne in triads of a central pistillate flower and two lateral staminate flowers, triads superficial or slightly sunken in shallow pits. Staminate flowers symmetrical, ± rounded to bullet-shaped, sometimes very small; sepals imbricate; petals valvate, basally briefly connate; stamens 3 (antesepalous or antepetalous) or 6 (very rarely 1, 4 or 5 as monstrosities), 3 staminodes sometimes present, these either antesepalous or antepetalous, very rarely adnate to the pistillode; pistillode present or absent. Pollen ellipsoidal, elongate ellipsoidal, pyriform or oblate triangular, with slight or obvious asymmetry; aperture usually a distal sulcus, occasionally a trichotomosulcus; ectexine usually tectate, occasionally semi-tectate, perforate, perforate and micro-channelled, perforate-rugulate, reticulate,muri of reticulum occasionally coarsely granular (rarely granularcrotonoid) or spinulose, aperture margin similar or slightly finer;infratectum columellate; less frequently ectexine intectate with coarselygranular structures, sometimes coalesced into larger elements with orwithout spinulae, aperture margin similar; longest axis 17–65 µm; post-meiotic tetrads usually tetrahedral, rarely tetragonal or rhomboidal[30/140]. Pistillate flowers about the same size as the staminate; sepalsrounded, broadly imbricate; petals imbricate with triangular valvate tips;staminodes usually present, minute, tooth-like, usually 3 or 6 at one sideof the ovary; pistil pseudomonomerous, often strongly asymmetrical(especially in smaller species), stigmas 3, apical, sometimes eccentric,ovule form unknown. Fruit borne with persistent calyx and corolla,spherical, ellipsoid, fusiform or rarely curved, stigmatic remains basal,often obscured by perianth; epicarp often brightly coloured or jet blackor rarely dull green or brown; mesocarp thin, fleshy or fibrous; endocarpusually thin, fibrous. Seed closely adhering to the endocarp, endospermhomogeneous, sometimes deeply pentrated by regular grooves, orweakly to strongly ruminate; embryo subbasal. Germination adjacentligular; eophyll bifid or pinnate. Cytology: 2n = 32, 34. (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Anatomy

  • Leaf (Achilli 1913, Tomlinson 1961), root (Seubert 1998a, 1998b) and floral (Rudall et al. 2003). (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Fossil record

  • From the Palaeocene-Lower Eocene, Deccan Intertrappean of India (Madhya Pradesh) (although the age span of these volcanic deposits is controversial, see Chapter 5) a petrified palm stem, Palmoxylon ghuguensis, is compared with Chrysalidocarpus (= Dypsis) (Ambwani and Prakash 1983). The affinity of the fossil is inconclusive. Small monosulcate grains, Palmaemargosulcites insulatus, from palm flower compression fossils, recovered from the Middle Eocene oil shales of Messel, Germany, are compared with pollen of Dictyocaryum and Dypsis (Harley 1997). (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Relationships

  • Dypsis has never been resolved as monophyletic in any study (Lewis and Doyle 2002, Baker et al. in prep.). A wide range of relationships have been recovered between Dypsis, Marojejya, Masoala and Lemurophoenix (and sometimes other Areceae), but these remain poorly supported (Lewis 2002, Lewis and Doyle 2002, Loo et al. 2006, Norup et al. 2006, Baker et al. in review, in prep.). Further data are required to facilitate a revision of the limits of Dypsis. (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Taxonomic accounts

  • Dransfield and Beentje (1995b). (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Bibliography

    A. Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms
    B. World Checklist of Arecaceae