Nenga H.Wendl. & Drude, Linnaea 39: 182 (1875)

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Discussion

Diagnosis

Biology And Ecology

Description

  • Moderate, solitary or clustered, acaulescent or erect, unarmed, pleonanthic, monoecious palms. Stem slender, short, rarely exceeding 5 m in height with short or elongate internodes and conspicuous leaf scars, stilt roots frequent. Leaves pinnate; sheaths usually forming a well-defined crownshaft with leaves neatly abscising, or leaves marcescent and crownshaft poorly developed (Nenga gajah); petiole usually well developed, flattened or grooved adaxially, rounded or angled abaxially; leaflets with 1–several folds, linear to sigmoid, acute or acuminate, the terminal pair obscurely lobed, lobes corresponding to the folds, the adaxial ribs often bearing ramenta on the under surface, transverse veinlets obscure. Inflorescence infrafoliar or interfoliar (N. gajah), erect or pendulous, branching to 1 order, rarely to 2 orders or unbranched, protandrous; peduncle short in species with infrafoliar inflorescences, long where inflorescences interfoliar (N. gajah); prophyll thin, membranous, enclosing the inflorescence in bud, splitting and falling at anthesis or thick, almost woody, persistent, eventually rotting; peduncular bracts incomplete, small, triangular; rachillae bearing spirally arranged minute bracts subtending triads proximally, solitary or paired staminate flowers distally, or triads confined to central rachilla and lateral rachillae with staminate flowers only, flowers not or only slightly sunken in the rachillae; floral bracteoles minute. Staminate flowers fleshy, sessile; sepals 3, connate at the very base, shorter than, almost as long as, or far exceeding the corolla; corolla with slightly stalk-like base or not, with 3 long, valvate lobes; stamens 6, borne at the base of the corolla lobes, filaments short, anthers oblong to linear, latrorse; pistillode absent. Pollen grains ellipsoidal to spheroidal, bi-symmetric; aperture a distal sulcus, short or same length as long axis; ectexine semi-tectate, coarsely reticulate, muri of reticulum may be spinulose, aperture margin similar; infratectum columellate; longest axis ranging from 37–72 µm [4/5]. Pistillate flowers sessile, globular; sepals 3, distinct, imbricate; petals 3, distinct, imbricate; staminodes absent or minute; gynoecium globose or columnar, uniloculate, uniovulate, style lacking, stigmas 3, massive, fleshy, divergent, ovule laterally attached, form unknown. Fruiting rachillae usually not differing greatly in colour from flowering ones. Fruit ovoid to obpyriform, dull to brightly coloured, stigmatic remains apical; epicarp smooth, dull or shiny, mesocarp thin, fleshy, sweet, endocarp composed of longitudinal fibres adhering to the seed, becoming free at both ends (N. pumila) or at one end only, the fibres enclosing a solid parenchymatous mass of varying size distal to the seed. Seed with longitudinal hilum and raphe branches anastomosing, endosperm deeply ruminate; embryo basal. Germination adjacent-ligular; eophyll bifid. Cytology not studied. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)

Fossil record

Relationships

Bibliography

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