Serenoa Hook.f., Gen. Pl. 3: 1228 (1883)

Primary tabs

Discussion

Diagnosis

Biology And Ecology

Uses

Description

  • Moderate, clustered, shrubby, armed, pleonanthic, hermaphroditic palm. Stem subterranean or prostrate and surface creeping, or rarely erect, covered with persistent leaf sheaths, axillary buds developing as either inflorescences or vegetative suckers. Leaves induplicate, palmate, marcescent; sheath expanding into a tattered mat of dark brown fibres; petiole flat to slightly rounded adaxially, rounded to angled abaxially, margin armed with numerous small teeth; adaxial hastula conspicuous, ± rounded, membranous, abaxial hastula semicircular, often split, membranous; blade nearly orbicular, regularly divided to below the middle into narrow stiff, shortly bifid, single-fold segments, glabrous except for scattered caducous scales along the ribs, midribs conspicuous abaxially, transverse veinlets conspicuous, rather distant. Inflorescences interfoliar, erect and about equaling the leaves but often hidden by them, curved, branched to 3(–4) orders; peduncle slender, flattened, rather short; prophyll tubular, 2-keeled, with 2 triangular apical lobes; peduncular bract 1 or lacking, tightly sheathing, caducously tomentose; rachis longer than the peduncle; rachis bracts like the peduncular bract but decreasing in size distally; first-order branches with a short 2-keeled prophyll; subsequent bracts small, membranous; rachillae spreading, densely tomentose, bearing spirally arranged, small, irregularly cleft bracts subtending solitary or paired flowers. Flowers with tubular calyx of 3 triangular, slightly imbricate lobes; corolla tubular, split to 2/3 its length into 3 lobes, valvate, inconspicuously grooved adaxially; stamens 6, filaments borne at the mouth of the corolla tube, gradually tapered, not inflexed, anthers erect in bud, elliptic, dorsifixed, somewhat versatile, latrorse; carpels 3, basally distinct, united in the attenuate stylar region to a narrow stigma, ovule anatropous. Pollen ellipsoidal, usually slightly asymmetric; aperture a distal sulcus; ectexine tectate, finely perforate, perforate and micro-channelled, or perforate rugulate, aperture margin slightly finer; infratectum columellate; longest axis 31–44 µm; post-meiotic tetrads tetrahedral or tetragonal, rarely rhomboidal [1/1]. Fruit ellipsoidal to subglobose, dark blue to black at maturity, abortive carpels basal, stigmatic scar apical or subapical; epicarp smooth, mesocarp fleshy without fibres, endocarp thin but somewhat cartilaginous. Seed basally attached with elongate raphe, endosperm homogeneous with a shallow lateral intrusion of seed coat; embryo lateral towards the base opposite the raphe. Germination remote-ligular; eophyll entire, plicate. 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

Fossil record

  • An ‘undoubted’ palmate leaf from the Middle Cretaceous formation at Glen Cove, Long Island, New York State is described as Serenopsis kempii by Hollick (1893), who considers it to be most like Trithrinax, Copernicia, Thrinax or Serenoa. However, Read and Hickey (1972) suggest that it is, “probably a cone of Williamsonia” (not a palm). (The long, thin, slightly sinuous leaflets of the fossil overlap near a poorly preserved central region.) Subfossil petioles and seeds (‘stones’) are reported by Berry (1917) from the Pleistocene of Vero (Florida). Fossil fruits are reported from southern England, Lower Eocene, Serenoa eocenica (Reid and Chandler 1933) and Germany (Geiseltal), Eocene,
    S. carbonaria (Mai 1976). Finely reticulate monosulcate pollen erroneously described as Serenoa has been reported from the Oligocene of the Isle of Wight (UK) by Pallot (1961), and from the Lower Eocene (London Clay) by Khin
    Sein (1961). (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)

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