Licuala Wurmb, Verh. Batav. Genootsch. Kunsten 2: 469 (1780)

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Number of Taxa

  • 162 species

Discussion

  • Easily recognizable by the wedge-shaped marginally reduplicate segments of the leaves of most species. Those with undivided leaves (Licuala grandis and L. orbicularis) are unlikely to be confused with other palms. The species examined differ from other coryphoid palms in having large transverse fibre-sclereids in the mesophyll of the leaf; in some epidermal characters, they resemble Pholidocarpus, Livistona and Johannesteijsmannia. (J. Dransfield, N. Uhl, C. Asmussen, W.J. Baker, M. Harley and C. Lewis. 2008)

Biology And Ecology

  • The species are mostly plants of the forest undergrowth; some are gregarious and lend a distinctive appearance to certain forest types, others are very local and occur as scattered individuals. A few species, e.g., L. calciphila, are strict calcicoles; L. spinosa, the most widespread species, occurs in forest on the landward fringe of mangrove and L. paludosa is common in peat swamp forest. A remarkable feature of some Bornean forest types is the abundance of Licuala spp. that grow sympatrically. (J. Dransfield, N. Uhl, C. Asmussen, W.J. Baker, M. Harley and C. Lewis. 2008)

Etymology

Diagnosis

  • Very small to moderate, solitary or clustered, hermaphroditic or dioecious fan palms of Southeast Asia to the western Pacific and Australia, usually immediately recognisable by the leaf being divided along the abaxial folds all the way to the petiole into wedge-shaped segments; there are a few species with undivided leaves. (J. Dransfield, N. Uhl, C. Asmussen, W.J. Baker, M. Harley and C. Lewis. 2008)

Description

  • Very small to moderate, solitary or clustered, acaulescent to shrubby, rarely tree-like, armed or unarmed, pleonanthic, hermaphroditic (very rarely dioecious) palms. Stem very short and subterranean, creeping or erect, ringed with close leaf scars, partly obscured by remains of leaf sheaths, sometimes bearing short bulbil-like shoots at the nodes. Leaves palmate, marcescent; leaf sheath disintegrating into a weft of fibres, the margin sometimes remaining as a broad, ligule-like ribbon or tongue; petiole adaxially channelled near the base, rounded or channelled distally, abaxially rounded or angled, armed along margins with close sharp teeth or triangular spines, or unarmed, caducous indumentum often abundant; adaxial hastula well developed, usually triangular, abaxial hastula absent; blade entire or split variously along the abaxial ribs to the very base to produce single to multiple-fold, wedge-shaped reduplicate segments, these in turn with very short splits along the abaxial folds and slightly longer splits along adaxial folds, the central segment usually entire, sometimes bifid, sometimes borne on a stalk-like extension, the ribs often with caducous indumentum, transverse veinlets usually conspicuous. Inflorescences interfoliar, much shorter to much longer than the leaves, very varied in aspect and degree of branching, from spicate to branched to 3 orders; peduncle short to very long, bearing a basal, 2-keeled tubular prophyll, and 0–5 or more, similar, tubular, closely sheathing or inflated, glabrous or tomentose, peduncular bracts; rachis bracts subtending usually distant, first-order branches adnate to the inflorescence axis above the bract mouth; subsequent orders of bracts minute; first-order branches spicate or branched further; rachillae few to ca. 30 or more, crowded or spreading, glabrous to variously scaly or hairy, bearing spirally arranged, distant or very crowded flowers. Flowers solitary or in groups of 2–3, sessile or borne on short to long spurs, each subtended by a minute triangular bract; calyx sometimes stalk-like at the base, tubular, truncate, irregularly splitting, or with 3 neat triangular lobes, glabrous or variously hairy; corolla usually considerably exceeding the calyx, tubular at the base, divided into 3 rather thick, triangular, valvate lobes, glabrous to variously hairy, usually marked near the tip on the adaxial face with the impressions of the anthers; stamens 6, epipetalous, the filaments distinct, somewhat flattened, or united into a conspicuous tube tipped with 6 equal, short to moderate teeth bearing erect or pendulous anthers, or androecial ring 3-lobed, 3 anthers borne on short distinct filaments, 3 borne at the sinuses between the lobes, anthers rounded or oblong, very small to moderate, latrorse; gynoecium tricarpellate, glabrous or variously hairy, carpels wedge-shaped, distinct in the ovarian region, united distally in a long, slender columnar style tipped with a minute dot-like stigma, ovules basally attached, anatropous. Pollen ellipsoidal, usually bisymmetric; aperture an extended distal sulcus; ectexine tectate, psilate, scabrate, perforate, perforate-rugulate, foveolate or finely reticulate, aperture margin slightly finer or similar; infratectum columellate; longest axis 28–50 µm; post-meiotic tetrads tetragonal or decussate [32/134]. Fruit globose, ovoid, narrow, straight, spindle-shaped or curved, perianth whorls usually persistent, 1–3 discrete carpels developing, abortive carpels frequently carried with the stigmatic remains at the tip of the fertile carpel, otherwise remaining at the base; epicarp frequently brightly coloured, dull or shining, rarely corky-warted, mesocarp fleshy, somewhat fibrous, thin to thick, endocarp thin, crustaceous. Seed basally attached, endosperm homogeneous or rarely ruminate, penetrated by a smooth or greatly lobed intrusion of seed coat, in species with spindle-shaped fruit the intrusion running ± the length of the seed in the middle; embryo lateral. Germination remote-tubular; eophyll strap-shaped, plicate, ± truncate and minutely lobed at the apex. Cytology: 2n = 28. (J. Dransfield, N. Uhl, C. Asmussen, W.J. Baker, M. Harley and C. Lewis. 2008)

Anatomy

Relationships

  • Preliminary analyses show that Licuala is monophyletic (Look 2007). Uhl et al. (1995) place the genus as sister to Johannesteijsmannia. Baker et al. (in review) and Asmussen et al. (2006) found low support for a sister relationship between Licuala and a clade comprising Johannesteijsmannia, Pholidocarpus and Pritchardiopsis. (J. Dransfield, N. Uhl, C. Asmussen, W.J. Baker, M. Harley and C. Lewis. 2008)

Taxonomic accounts

Fossil record

  • From the Indian Deccan Intertrappean (although the age span of these volcanic deposits is controversial, see Chapter 5), Ambwani (1983) reports palm wood, Palmoxylon shahpuraensis, from Madhya Pradesh. He considers it comparable to a number of species of Licuala, although wood identifications to genus should always be viewed with caution. Silicified fruits, Palmocarpon coryphoidium, which, “come very close to some species of Pritchardia and Licuala specially [sic] the latter” (Shete and Kulkarni 1985) are reported from the Deccan Intertrappean of Maharashtra. Again, the generic affinity of these fossil fruits remains doubtful. (J. Dransfield, N. Uhl, C. Asmussen, W.J. Baker, M. Harley and C. Lewis. 2008)

Uses

  • Leaves of some species are used for thatching and for making sleeping mats. The sword leaf of some may be used for wrapping food before or after cooking. Smaller stems are used for walking sticks and larger ones as palisades in building. Many species are highly decorative but appear generally to be slow growing. Pith and stem apices are edible. (J. Dransfield, N. Uhl, C. Asmussen, W.J. Baker, M. Harley and C. Lewis. 2008)

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.