Laccosperma Drude, Bot. Zeitung (Berlin) 35: 632 (1877)

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Number of Taxa

  • 6 species

Discussion

  • Very rarely in Laccosperma, triads of hermaphroditicflowers are present and bract arrangement indicates asympodial nature for the triad and the dyad. (J. Dransfield, N. Uhl, C. Asmussen, W.J. Baker, M. Harley and C. Lewis. 2008)
  • The provision of a satisfactory taxonomy of this genus has been hindered by a paucity of adequate fertile material and inadequate field observations to date. Despite a number of species being described, very few species names have been applied. Most notable is the fact that the name L. secundiflorumhas been far too widely applied to three morphologically distinct species of large-diameter Laccosperma. This is an understandable mistake to make, especially as the flowers and fruits of all these species show a remarkable similarity, although there are some morphological differences (fide Beccari 1910). In the field, however, where these species are often sympatric, they are easily distinguished from each other. (T.C.H Sunderland. 2012)

Biology And Ecology

Common Name

Etymology

Diagnosis

Description

  • Clustered, spiny, high-climbing, hapaxanthic, hermaphroditic, rattan palms. Stem sometimes branching aerially, eventually becoming bare, with long internodes, circular in cross-section, sucker shoots apparently axillary. Leaf pinnate with a cirrus; sheath strictly tubular, variously armed with scattered spines and abundant caducous indumentum; ocrea conspicuous, split opposite the leaf, scarcely sheathing, sometimes slightly inflated with inrolled edges and ant-infested, unarmed or armed like the sheath; knee absent; petiole present, usually armed with scattered or grouped spines abaxially and along margins, and frequently indumentose, rarely unarmed; rachis armed like the petiole; cirrus armed with reflexed spines and bearing neat pairs of reflexed acanthophylls; leaflets few to very numerous, 1–4-fold, entire, linear to sigmoid, regularly or irregularly arranged, often fiercely armed with short spines along the margins and the main ribs, midribs prominent adaxially, transverse veinlets conspicuous or inconspicuous. Inflorescences produced simultaneously in the axils of the most distal few frequently reduced leaves, branched to 1 order; peduncle enclosed within the leaf sheath and emerging from its mouth or bursting through the sheath, not adnate to the internode, ± hemispherical in cross-section; prophyll strictly tubular, 2-keeled, enclosed within the leaf sheath; peduncular bracts 1–3; rachis longer than the peduncle; rachis bracts distichous, strictly tubular with a triangular limb, without spines, sparsely indumentose, becoming tattered, each subtending a pendulous or spreading rachilla; rachilla prophyll tubular, 2-keeled, included within the subtending bract, rachilla bracts distichous, tubular with apiculate, triangular limb, striate, sparsely indumentose, the margin sometimes ciliate, each, except sometimes for the basal 1–2, subtending a flower cluster. Flowers very rarely borne in triads, usually in dyads, sometimes solitary towards the tips of the rachillae, the flower cluster bearing a tubular 2-keeled prophyll and 0, 1, or 2, 2-keeled bracteoles (depending on the number of flowers); calyx slightly to strongly stalk-like at the base, often bent at right angles, incompletely divided distally into 3 triangular striate lobes; corolla tubular at the very base, divided above into 3 oblong, narrow, triangular, valvate lobes; stamens 6, borne at the very base of the corolla, filaments distinct, much swollen, angular, scarcely narrowed at the connective, anthers medifixed, oblong, latrorse; gynoecium tricarpellate, triovulate, ovary covered with scales, those at the base of the style minute, spine-like, style elongate, 3-angled, stigma minute, pyramidal, ovules basally attached, anatropous. Pollen ellipsoidal, bi-symmetric; aperture a distal sulcus; ectexine tectate, finely to coarsely perforate, or rugulate-reticulate, aperture margin finer; infratectum columellate; longest axis 37–75 µm [4/5]. Fruit 1-seeded (?always), tipped with the base of the style, the rest of the style usually breaking off early in fruit development, the perianth whorls persistent; epicarp covered in vertical rows of reflexed scales with fringed margins, mesocarp fleshy and sweet at maturity, endocarp not differentiated. Seed attached subbasally at one side, ovoid and laterally flattened, or rounded and deeply scalloped, with a very shallow to very deep lateral pit, seed coat apparently sometimes fleshy, endosperm homogeneous; embryo lateral, opposite the pit. Germination adjacent-ligular; eophyll bifid. Cytology not studied. (J. Dransfield, N. Uhl, C. Asmussen, W.J. Baker, M. Harley and C. Lewis. 2008)
  • Clustered, spiny, understorey to high climbing, hapaxanthic, hermaphroditic rattan palms. Stems, circular in cross section, rarely oval, with medium to long internodes; sucker shoots axillary. Leaf pinnate, with cirrus; sheath strictly tubular, sparsely to profusely armed with fine scattered spines, sometimes becoming bare; ocrea conspicuous, split opposite the petiole, scarcely sheathing, rarely inflated with inrolled edges or reflexed and tattering, armed as the sheath; knee absent; petiole short to long, much shorter in the reduced leaves subtending the inflorescences, usually armed with inequidistant angular spines along margins, never unarmed; rachis armed as the petiole; cirrus armed with reflexed prickle-like spines and bearing neat pairs of reflexed acanthophylls; leaflets few to very numerous, 1-4 fold, entire, linear to sigmoid, regularly or irregularly arranged, often fiercely armed with short to long spines along the margins and the main ribs, midribs prominent adaxially, transverse veinlets conspicuous or inconspicuous; acanthophylls alternate proximally, sub-opposite to opposite distally. Inflorescences produced simultaneously in the axils of the most distal few, frequently reduced leaves, branched to 1-order; peduncle enclosed within the leaf sheath and emerging from its mouth, ± hemispherical in cross section; prophyll strictly tubular, 2-keeled, enclosed within the subtending leaf sheath; peduncular bracts 1-3; rachis longer than the peduncle; rachis bract distichous, strictly tubular with a triangular limb, without spines, sparsely to profusely indumentose, becoming tattered at apex, each subtending a pendulous or spreading rachilla; rachilla prophyll tubular, 2-keeled, included within the subtending bract, rachilla bracts distichous, tubular with apiculate triangular limb, striate, sparsely indumentose, the margin sometime ciliate, each, except for the basal 1-2, subtending a flower cluster. Flowers usually in dyads, rarely in triads, sometimes solitary towards the tip of the rachillae, the flower cluster bearing a 2-keeled prophyll and 0, 1 or 2, 2-keeled bracteoles (depending on the number of flowers); calyx slightly to strongly stalk-like at the base, often bent at right angles, incompletely divided distally into 3-triangular striate lobes; corolla tubular at the very base, divided above into 3 oblong , narrow, triangular, valvate lobes; stamens 6, epipetalous, filaments distinct, much swollen, angular, scarcely narrowed at the connective; anthers medifixed, oblong, latrorse, pollen elliptic, monosulcate with finely reticulate, tectate exine; gynoecium tricarpellate, triovulate, ovary covered with scales, those at the base of the style minute, spine-like, style elongate, 3-angled, stigma minute, pyramidal, ovules basally attached, anatropous. Fruit baccate, 1-sometimes 2-seeded, tipped with the base of the style, the remainder of the style usually breaking off in early fruit development, calyx and corolla persistent at base; epicarp covered in vertical rows of reflexed scales with fringed margins, mesocarp white, fleshy and sweet at maturity, endocarp not differentiated. Seed attached sub-basally at one side, ovoid and laterally flattened, or rounded and deeply scalloped, with a very shallow to deep, lateral pit, seed coat fleshy, endosperm homogenous; embryo lateral, opposite the depression or pit. Germination adjacent-ligular; eophyll bifid. (T.C.H Sunderland. 2012)

Relationships

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.
  • Sunderland, T.C.H2012. A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae).