Lepidocaryum Mart., Hist. Nat. Palm. 2: 49 (1824)

Primary tabs

http://media.e-taxonomy.eu/palmae/photos/palm_tc_110826_9.jpg

Distribution

Map uses TDWG level 3 distributions (http://www.nhm.ac.uk/hosted_sites/tdwg/geogrphy.html)

One species with three varieties, distributed in the wetter parts of Colombia, Peru, Venezuela, Guyana and Brazil. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

Discussion

Diagnosis

Description

  • Slender, clustered, unarmed, pleonanthic, dioecious, undergrowth palms. Stem erect, colonial by slender rhizomes, partly obscured by marcescent leaf sheaths above, becoming bare basally, with rather short internodes and inconspicuous nodal scars. Leaves small, reduplicately palmate; sheath splitting opposite the petiole, frequently covered with very dense, caducous tomentum; petiole conspicuous, ± rounded in cross-section except at the base where channelled adaxially; hastulae mostly absent, a low crest sometimes present adaxially; blade flabellate or ± orbicular with a very short costa, divided along a few abaxial folds to the insertion into few broad or narrow single-fold or compound, spathulate, acuminate segments, tips sometimes bristly, blade surfaces similar in colour, midribs more prominent abaxially, transverse veinlets conspicuous, rather distant and somewhat sinuous; young leaves sometimes reddish-tinged. Inflorescences solitary, interfoliar, the staminate and pistillate superficially similar, branched to 2 orders; prophyll tubular, closely sheathing, 2-keeled, with 2 short triangular lobes; peduncle elongate, bearing several (ca. 6) closely sheathing tubular bracts with short triangular limbs; rachis longer than the peduncle; rachis bracts like the peduncular, but tending to split at the tip, each subtending a first-order branch; first-order branches few, rather short, bearing a basal, tubular, 2-keeled prophyll and sometimes 1 empty tubular bract, and distichously arranged, tubular, triangular-tipped bracts, each subtending a rachilla; staminate rachilla short, becoming recurved, with a basal, membranous, striate, 2-keeled prophyll and few (up to 12) distichous, membranous, apiculate, cup-shaped bracts, each, including sometimes the prophyll, subtending a solitary staminate flower bearing a 2-keeled bracteole, or a pair of staminate flowers enclosed within a 2-keeled, explanate bracteole, one of the pair bearing a second bracteole; pistillate rachilla usually very short, sometimes scarcely exserted from the subtending bract, bearing a basal, membranous, 2-keeled, striate prophyll and few (up to ca. 8) distichous, membranous, cup-like, apiculate bracts, each, including sometimes the prophyll, subtending a solitary pistillate flower, bearing a 2-keeled bracteole and a minute, ovate, flattened second bracteole. Staminate flowers symmetrical; calyx tubular, briefly 3-lobed, ± striate; petals much exceeding the calyx, basally connate, the tips valvate; stamens 6, borne at the very base of the petals, filaments thick, fleshy, ± angled, the anthers small, basifixed, latrorse; pistillode minute or short, columnar. Pollen ellipsoidal, bi-symmetric; aperture a distal sulcus; ectexine intectate, surface very finely granular, interspersed with bottle-shaped spines set in, and loosely connected to, cavities in a wide foot layer, bulging noticeably inward beneath each spine, the inner face of the foot layer clearly lamellate, aperture margin similar; longest axis 28–41 µm [1/1]. Pistillate flowers larger than the staminate; calyx tubular, 3-lobed, splitting somewhat irregularly after fertilization; corolla much exceeding the calyx, tubular in basal ca. 1/3, with 3 elongate, valvate lobes; staminodes 6, adnate to the base of the corolla lobes, the filaments somewhat angled, the empty anthers minute; gynoecium incompletely trilocular, triovulate, ± rounded, covered in vertical rows of reflexed scales, style conical, briefly 3-lobed, ovule anatropous, ?basally attached. Fruit rounded or oblong, usually 1-seeded, with apical stigmatic remains; epicarp covered in vertical rows of reflexed reddish-brown scales, mesocarp thin, endocarp not differentiated. Seed attached near the base at one side, with a shallow furrow along the raphe, testa ?fleshy, endosperm homogeneous; embryo lateral. Germination adjacent-ligular; eophyll bifid. Cytology: 2n = 30. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

Fossil record

  • Monosulcate spiny pollen grains resembling those of Lepidocaryum gracile (‘or Nuphar luteum’) are described from the Upper Cretaceous (Senonian) of Gabon (Boltenhagen 1967). The size of the grains (28–41 µm) is more comparable to Lepidocaryum pollen than to pollen of N. luteum (>45 µm). Furthermore, unlike Lepidocaryum, Nuphar is associated with cold or cool climates; Salard-Cheboldaeff (1978, 1981) associated Echimonocolpites rarispinosus (44–45 µm long axis) from the Lower Eocene of Cameroon with Lepidocaryum, although this is an uncertain comparison. The pollen grains of Mauritia, although similar morphologically, are much larger (54–65 µm) than those of Lepidocaryum. Neither Lepidocaryum nor Mauritia are present in the African continent today, although Mauritia has a notable pollen fossil record in Africa. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

Relationships

Use Record

Uses