Leucothrinax C.Lewis & Zona, Palms (1999+) 52: 87 (2008)Protologue

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Discussion

Diagnosis

Etymology

Description

  • Small to moderate, solitary, unarmed, pleonanthic, hermaphroditic palm. Stem erect, columnar, smooth, grey, obscurely ringed with leaf scars, usually with a basal mass of fibrous roots. Leaves induplicate, palmate; sheath becoming split both opposite the petiole and abaxially to emit the inflorescence, disintegrating into a network of irregular fibres, covered in thick, deciduous tomentum, margins fibrous; petiole long, slender, rounded to shallowly ridged both adaxially and abaxially, densely covered with caduceus white indumentum, margins rather sharp; adaxial hastula prominent, rounded to triangular, densely covered in caducous hairs, abaxial hastula very short, apically membranous and disintegrating; blade fan-shaped, with irregularly folded segments, not held in the same plane, split apically to ca. 1/2 their length or more into lanceolate, pointed and usually bifid segments, glabrous adaxially, abaxially covered in white wax and bearing minute punctiform scales, midrib and marginal ribs conspicuous, transverse veinlets evident. Inflorescences interfoliar, slender, erect to arching, equalling or exceeding the leaves, branched to 2 orders, primary branches pendulous; peduncle moderate, rather slender, round in cross-section; prophyll short, tubular, 2-keeled, pointed, opening distally, tomentose; peduncular bracts several (ca. 3), like the prophyll but lacking keels, overlapping and very closely sheathing the peduncle; rachis longer than the peduncle, slender, tapering, bearing spirally arranged, long, tubular, pointed distally and obliquely open primary bracts subtending first-order branches; first-order branches each with a short to long basal bare portion, bearing a 2-keeled, bifid prophyll and spirally arranged, narrow, triangular bracts subtending rachillae; rachillae slender, rather short, stiff, bearing spirally arranged, small triangular bracts subtending solitary flowers, bracteoles apparently lacking. Flowers ± sessile; perianth a single cupule with 6 lobes or teeth; stamens mostly 6, filaments basally broadly connate in a ring equalling the perianth, free portion very slender, anthers elongate, dorsifixed near the base, emarginate apically, latrorse; gynoecium consisting of 1 carpel, unilocular, uniovulate, ovule basally attached, erect, campylotropous but tilted so that the micropyle faces the upper dorsal wall of the locule, and with a basal aril. Pollen ellipsoidal with slight to obvious asymmetry; aperture a distal sulcus; ectexine tectate, finely perforate, aperture margin similar; infratectum columellate; longest axis 21–31 µm [1/1]. Fruit very small, white at maturity, stigmatic remains apical, perianth persistent; epicarp smooth when fresh, mesocarp thin, endocarp very thin, papery. Seed depressed-globose, smooth, hilum round, impressed, forming a basal intrusion, raphe branches scarcely impressed, endosperm homogeneous; embryo subapical. Germination remote-tubular; eophyll narrow, lanceolate. Cytology: 2n = 36. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)

Anatomy

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