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

Primary tabs

http://media.e-taxonomy.eu/palmae/photos/palm_tc_65524_4.jpg

Distribution

Map uses TDWG level 3 distributions (http://www.nhm.ac.uk/hosted_sites/tdwg/geogrphy.html)
Comorospresent (World Checklist of Arecaceae )B
Madagascarpresent (World Checklist of Arecaceae )B
Tanzaniapresent (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. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

Discussion

Diagnosis

Biology And Ecology

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

Anatomy

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

Relationships