Trithrinax Mart., Hist. Nat. Palm. 2: 149 (1837)

Primary tabs

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Number of Taxa

  • 4 species

Discussion

Biology And Ecology

Common Name

Etymology

Diagnosis

Description

  • Moderate, solitary or sometimes clustering, armed, pleonanthic, hermaphroditic palms. Stem erect, clothed with persistent, fibrous, sometimes spiny leaf sheaths, eventually becoming bare, rough, and longitudinally striate. Leaves induplicate, palmate, marcescent; sheath tubular, drying into a fibrous, often ± woody network, the upper fibres becoming stout rigid spines; petiole adaxially shallowly channelled or rounded, abaxially rounded, the margins entire, sharp; adaxial hastula triangular or deltoid usually with a definite point, abaxial hastula similar, often smaller; blade fan-shaped to nearly circular, not or only slightly costapalmate, nearly regularly divided beyond the middle (Trithrinax biflabellata divided centrally, almost to the base) into numerous single-fold, stiff segments with shallowly to deeply bifid, apiculate to sharp tips, adaxially glabrous, abaxially lightly waxy and tomentose, midribs more prominent abaxially, other veins numerous, small, transverse veinlets not evident. Inflorescences solitary, interfoliar, rather short to moderate, robust, curved, creamy-white when young, branched to 3 orders; peduncle short; prophyll and 2(–3) peduncular bracts similar, inflated, tubular at base, expanded and split along one side, slightly keeled dorsally toward the apex, with short solid tips, glabrous or densely but irregularly tomentose; rachis longer than the peduncle; rachis bracts like peduncular bracts but becoming smaller, absent distally, each subtending a first-order branch; first-order branches adnate to the rachis and often to the tubular base of the next higher bract, stout, curved, bearing chartaceous, small, triangular bracts subtending rachillae; rachillae spirally arranged, ± equal in length, much shorter than first-order branches, bearing small elongate triangular bracts each subtending a flower. Flowers spirally arranged, solitary on short stalks, slightly asymmetrical; sepals 3, very shortly united basally, ovate; petals 3, ± twice as long as the sepals, ovate, imbricate, fleshy, acute; stamens 6, exserted, filaments distinct, twice as long as the petals, slender, tapering, anthers linear oblong, versatile, latrorse; carpels 3, distinct, ovarian part obovoid, attenuate to a tubular, short to long, erect or recurved style with apical stigma, ovule basal, hemianatropous, with aril. Pollen grains ellipsoidal, with slight to obvious asymmetry; aperture a distal sulcus; ectexine tectate, finely perforate, perforate and micro-channelled, or perforate-rugulate, aperture margin slightly finer or psilate; infratectum columellate; longest axis 25–45 µm [2/3]. Fruit 1-seeded, white, globose, stigmatic scar apical, abortive carpels basal; epicarp smooth, mesocarp fleshy, endocarp thin, papery. Seed becoming free, globose, hilum circular, basal with ascending branches, endosperm homogeneous with deeply intruded seed coat below the raphe; embryo lateral, opposite the raphe. Germination remote-tubular (Chavez 2003); eophyll simple. Cytology: 2n = 36. (J. Dransfield, N. Uhl, C. Asmussen, W.J. Baker, M. Harley and C. Lewis. 2008)

Anatomy

Relationships

Taxonomic accounts

Fossil record

Uses

Bibliography

  • Dransfield, J. , Uhl, N. , Asmussen, C. , Baker, W.J. , Harley, M. & Lewis, C. 2008. Genera Palmarum. The evolution and classification of palms. Kew Publishing, Royal Botanic Gardens Kew.