Loxococcus H.Wendl. & Drude, Linnaea 39: 185 (1875)

Primary tabs

Placement status: taxon unplaced
https://media.e-taxonomy.eu/palmae/photos/palm_tc_115242_8.jpg

Distribution

Map uses TDWG level 3 distributions (https://github.com/tdwg/wgsrpd)
Sri Lanka present (World Checklist of Arecaceae)B
One species in Sri Lanka. (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Discussion

  • Loxococcus is a rather poorly known genus. Thoughhandsome, it seems to be in only a few collections. (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Diagnosis

  • Moderate solitary pinnate-leaved palm from rain forest in Sri Lanka, with conspicuous crownshaft, praemorse leaflets and asymmetrical staminate flowers with 12 stamens; the seed is deeply ruminate. (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Biology And Ecology

  • On cliffs, rocks and steep slopes in humid rain forest at altitudes of 300–1600 m. (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Common Name

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

Etymology

  • Loxos — slanting, kokkos — seed, referring to the oblique development of fruit and seed. (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Uses

  • Seed is rarely used as asubstitute for betel. (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Description

  • Moderate, solitary, unarmed, pleonanthic, monoecious palm. Stem erect, rather slender, conspicuously ringed with leaf scars, sometimes slightly swollen at the base. Leaves stiff, pinnate, neatly abscising; sheaths forming a well-defined crownshaft, bearing sparse scales; petiole usually very short, adaxially channelled, abaxially rounded, sparsely scaly; rachis adaxially becoming angled distally, abaxially rounded; leaflets mostly single-fold except for the terminal pair and, rarely, the basal pair, regularly arranged, generally rather stiff and coriaceous, linear, close, the apices praemorse, truncate or oblique, glabrous adaxially, abaxially paler with very thin, white, caducous indumentum and conspicuous ramenta along the midrib near the base, midrib prominent, transverse veinlets not visible. Inflorescences infrafoliar, rather short, stiff, spreading, branching to 2 orders basally, to 1 order distally, apparently protandrous; peduncle short, the base bulbous and with 2 clasping wings; prophyll borne just above the base of the peduncle, narrow, ovate, beaked, laterally 2-keeled, entirely enclosing the inflorescence until leaf fall, then splitting longitudinally, bearing abundant, scattered scales; peduncular bract borne just above the prophyll, much shorter than the prophyll, lanceolate, acuminate, apparently not completely sheathing the inflorescence, incompletely encircling the peduncle, scaly as the prophyll; 1 or 2 small, triangular, acuminate, open, peduncular bracts sometimes present; rachis stiffly projecting upward, much longer than the peduncle, bearing spirally arranged small, triangular, acuminate bracts subtending branches and rachillae; rachillae rather flexuous, short, stout, deep crimson at anthesis, glabrous, bearing spirally arranged, very small, low, triangular bracts subtending flower groups, flowers borne in triads for 1/2–3/4 the rachilla length, with solitary or paired staminate flowers distally; floral bracteoles minute. Staminate flowers somewhat asymmetrical, ± fleshy; sepals 3, distinct, imbricate, broadly triangular, keeled, the margins minutely toothed; petals 3, elongate, unequal, briefly connate basally, valvate, tips triangular; stamens 12, filaments short, slender, distinct, anthers ± sagittate at the base, elongate, latrorse; pistillode ± conical, domed, or 3-angled with 3 short slender appendages (?vestigial stamens). Pollen ellipsoidal asymmetric; aperture a distal sulcus; ectexine tectate, psilate-perforate, aperture margin similar; infratectum columellate; longest axis ranging from 40–44 µm [1/1]. Pistillate flowers ± globular; sepals 3, distinct, imbricate, short, broad, keeled; petals 3, distinct, imbricate, the tips minutely valvate at anthesis, about twice as long as sepals; staminodal ring low, membranous, with ca. 9, irregular, triangular lobes; gynoecium unilocular, uniovulate, spherical, stigmas 3, reflexed apically, ovule laterally attached, form unknown. Fruit reddish-brown at maturity, ± spherical with a short, broad, slightly eccentric beak tipped with the stigmatic remains, perianth whorls persistent; epicarp smooth, mesocarp thin with numerous longitudinal, pale fibres, becoming free basally after disintegration of epicarp, endocarp thin, not adhering to the seed. Seed globose, basally and laterally attached with a ± circular, basal, slender, lateral hilum running ± the length of the seed, endosperm deeply ruminate; embryo basal. Germination and eophyll not recorded. Cytology: 2n = 32. (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Anatomy

  • Fruit (Essig andYoung 1979). (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Fossil record

  • No generic records found. (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Relationships

  • It is striking that this Indian Ocean palm resolvesas sister to the western Pacific clade with moderate support (Looet al. 2006, Baker et al. in prep.). Loxococcus has also been poorlysupported as sister to Hydriastele (Baker et al. in review). (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Taxonomic accounts

  • Beccari and Pichi-Sermolli (1955). (Dransfield, J., Uhl, N., Asmussen, C., Baker, W.J., Harley, M. & Lewis, C. 2008: Genera Palmarum. The evolution and classification of palms)A

Bibliography

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