Laccosperma secundiflorum
Laccosperma (lah-koh-SPEHR-mah) secundiflorum (seh-koon-dih-FLOHR-uhm) | |||||||
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Kumba-Nguti Road, Cameroon. Photo by Dr. John Dransfield, Royal Botanic Gardens, Kew/Palmweb. | |||||||
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Contents
Habitat and Distribution
Benin, Cabinda, Cameroon, Central African Republic, Gabon, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Niger, Nigeria, Senegal, Sierra Leone, Togo, and Zaire. This species is distributed from Senegal to Cameroon south to Democratic Republic of Congo. Laccosperma secundiflorum is a species of high forest, and is commonly found under a forest canopy.Laccosperma secundiflorum occurs up to 1050 m altitude in high forest, rarely in secondary forest. It is particularly abundant in seasonally inundated and swampy areas. It grows well in poorly drained waterlogged soils in areas where the average annual rainfall is below 1600 mm. In areas with an average annual rainfall over 1750 mm, however, it prefers well-drained locations. The species prefers gaps in dense high forest, and it benefits from a certain amount of forest disturbance. The rootstock is easily killed by fire and it will not regenerate in areas that have been burnt several times in the past.
Description
Clustered moderate to robust palm, climbing to 25-50 m. Stems without sheaths 20-25 mm in diameter; with 30-35 mm; internodes 18-35 cm long. Leaf sheath dark green, lightly striate, moderately to sparsely armed with black-tipped finely triangular, upward-pointing or spreading spines; sheaths on upper portion of stem more sparsely armed; sparse black indumentum present on mature sheaths; ocrea 25-35 cm long, dry, often tattering, gradually tapering at the apex, dark tan coloured without, shiny dark brown to dull maroon within, armed as the sheath, spines concentrated at apex. Leaves up to 3.5 m long; petiole 30-60 cm long, 1.5-1.8 cm wide, commonly at 45-60° angle to the sheath, light to mid-green to straw coloured often with scattered brown indumentum below, abaxially rounded, adaxially concave, becoming flattened, somewhat rectangular in cross section distally, armed along the margins with inequidistant black-tipped spines up to 1.8 cm long, angular, spreading in many directions; rachis up to 1.2-1.5m long, hexagonal in cross section proximally becoming trapezoid then rounded in cross section distally, armed as the petiole, spines becoming increasingly short and more sparse distally; cirrus up to 1.5-1.8m long, armed on the underside with inequidistant, reflexed, black-tipped spines, with sparse brown indumentum below; leaflets composed of 2-4-folds, 25-40 on each side of the rachis, equidistant, often variable in width, arching from the rachis, not strictly pendulous, sigmoid, elongate, leaflet apex very finely acuminate with tip often breaking off, 35-45 cm long × 3-8 cm broad at the widest point, concolorous or somewhat discolorous with a darker green adaxial surface, leaflet margin armed with fine to robust, 1-2 mm-long, forward-facing, equidistant black-tipped spines, 1,2 or 3 costulate, each vein armed as the leaflet margin; acanthophylls, up to 4 cm long. Inflorescences, numbering 6-10, produced simulataneously in the distal 1-1.8 m portion of stem; peduncle 15-20 cm long; prophyll 8-10 cm; rachis branches 25-35 cm long, perpendicular to the main axis; rachis bracts 2.5-3 cm long, decreasing distally, dry, often tattering, tapering to form an elongate acutely triangular lobe on the abaxial side, closely adpressed to the bract above, covered with a dense brown indumetum; rachillae 15-25 cm long, pendulous, densely covered with imbricate bracts ca.7 mm long, dry and triangular at apex, each with a wide opening and a 1.5 mm-long apiculum. Flowers at anthesis 1-1.2 cm × 3.0-3.5 mm; calyx 5-5.5 mm long, excluding angular 3 mm-long stalk, 3-3.5 mm wide, dark tan coloured, tubular in the basal 1.5-2 mm, with 3 longitudinally-striate or mottled rounded to bluntly triangular lobes ± 4.5 mm × 3 mm; corolla tubular in the basal 1 mm only, with 3 valvate lobes, white or pale cream, longitudinally striate or mottled, ± 9 mm × 2 mm with a bluntly acuminate tip; stamen filaments dark brown, 4 mm × 1 mm, united into a 2 mm-long basal tube; anthers 3 mm × 1 mm; ovary ca.1 mm in diameter, stigma up to 5 mm long. Fruit ovoid, 1.8-2 cm × 1.3-1.5 cm, with 18-22 vertical rows of scales. Seed smooth, ovoid, 1-1.2 cm long, 0.8-1.2 cm wide, 0.5-0.7 mm deep, lightly flattened on one side. (T.C.H Sunderland, A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae) in Phytotaxa 51. 2012)/Palmweb. Editing by edric.
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A number of species of the large diameter members of the genus Laccosperma were described in the early part of the 20th century by Beccari (1910) and de Wildemann (1916), and later by Burret (1942). Although Burret, in particular, was prone to applying very narrow typological species concepts (see Henderson 1999), he has been proven to be somewhat accurate in the majority of his species accounts within this genus and Oncocalamus. Despite this, and obvious morphological discontinuities within this complex, evident both from herbarium material and field observations, many of the species described both by Burret and Beccari were never recognised. One of the major reasons for this is the fact that in their original paper in which Mann & Wendland (1864) re-described Laccosperma secundiflorum (syn. Calamus secundiflorus), the account was accompanied by an illustration by Fitch, probably based on Mann's field sketches, that showed the growth habit of a number of African palms, including that of L. secundiflorum. However, with its conspicuously pendant, and distinctively linear leaflets, the rattan palm labelled in the account as "L. secundiflorum" bears little resemblance to the species of Palisot de Beauvois, nor indeed to the original collections of Mann the account cites. The taxon drawn is undoubtedly a species described later by Burret (1942) as L. robustum. This confusion seems to have given credence to the oft-mentioned claim of many of the subsequent floristic studies that L. secundiflorum is a highly polymorphic taxon both within and between populations. As such, these floristic studies continued to group all of the large-diameter species of Laccosperma into a single species complex: L. secundiflorum(Drude 1895, Wright 1902, Unwin 1920, Dalziel 1937, Renier 1948, Robyns & Tournay 1955, Irvine 1961, Russell 1968, Letouzey 1978, Dransfield 1986, Berhaut 1988, Morakinyo 1995). However, field workers began to note that there were in fact at least two species of large-diameter Laccosperma in West and Central Africa. The morphological differences between taxa are obvious, particularly as these species are often sympatric. Paul Tuley, who was working in Nigeria in the 1950's-60's, wrote to Tom Russell at Kew, who was then preparing an account of the Palmae for the revision of the Flora of West Tropical Africa. Tuley suggested to Russell that there might be at least two "forms" within the L. secundiflorum complex with "one [form] having dropping segments and the other with rigid segments that are held horizontally". Tuley was quite clearly describing, in the first instance, the pendant leaflet habit of L. robustum. However, Russell discounts his observations, and states that ?all the flowering material at Kew, including collections of Tuley, are referrable to Ancistrophyllum secundiflorum? Russell (1968). In addition, Chapin, a botanist active in the then Belgian Congo makes the distinction between the true L. secundiflorumand "the one with pendant leaflets that grows in swamps" (Chapin 613, herb. BR!) (author's translation from the French). A brief discussion of this is also reported by Prance et al. (2000). Tuley (1995) went some way in distinguishing between the taxa, in describing L. acutiflorum and L. secundiflorum as separate species, but no doubt a lack of adequate voucher material hindered the preparation of a full account of this group. However, since then, further field-work and examination of herbarium material has confirmed that this ?taxon? is composed of three distinct species: Laccosperma secundiflorum, L. robustum and L.acutiflorum. (T.C.H Sunderland, A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae) in Phytotaxa 51. 2012)/Palmweb. |
Culture
Laccosperma secundiflorum can be propagated with seed or vegetatively using rhizomes or suckers. Seed propagation is more common since it is difficult to gather large quantities of suckers or rhizomes due to their bulkiness. However, seed germination is slow and seed mortality high. In trials in Cameroon emergence took as long as 100 days, with a germination rate of only 19%. This may be due to the seed having a relatively robust seed coat, which impedes imbibition, causing a dormancy that can delay germination for 9–12 months. In trials in Cameroon, the average time from planting to shoot emergence was 74 days for suckers and 84 days for rhizomes. In a trial in Côte d’Ivoire shoots emerged from suckers 35–56 days after planting, but shoots did not develop from rhizomes. In-vitro propagation using axillary bud and apical meristem explants has proven possible, but for mass propagation the reliability and efficiency of the protocol need to be improved. Cold Hardiness Zone: 10b. (PROTA4U)
Comments and Curiosities
Etymology: From the Latin; refers to the inflorescence structure with hermaphrodite flowers in pairs.
Uses: The whole stems are mainly used for furniture framework, but also for binding and for walking sticks, baskets, fish-traps, suspension bridges and drumsticks. Thinner stems are used as rope. Split stems with the pith scraped out are used for basketry, fish-traps and as tying material. In Cote d’Ivoire the split stems are used in the fabrication of traditional drums by securing the goat-skin onto a wooden frame. Potential uses of the stem include the production of particle board and briquettes from waste material from furniture making. The leaves have been used as a thatching material in Sierra Leone, Ghana and Nigeria. The apical bud (palm heart) is eaten, sometimes even raw. The young shoots are eaten boiled and fried as a vegetable. The soft pith of young shoots is also eaten. Sap from the stem is potable. In Côte d’Ivoire women eat the boiled apical bud with the leaves of Caesalpinia bonduc (L.) Roxb. for the treatment of sterility-provoking stomach-ache. The soft pith of young shoots and a tea made from the young shoots are used against worms. In Cameroon an infusion of the leaves is taken against stomach-ache and dysmenorrhoea, the young shoots are a remedy against fever and dysentery and the sap is a vermifuge. In Cameroon and Congo the fresh stem is part of a preparation externally applied on dermatoses.
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Production and international trade: Laccosperma secundiflorum is important both at subsistence level and for commercial utilisation. Its unit of trade is the ‘packet’. A packet of Laccosperma secundiflorum represents twenty stems, with each stem being 3–4 m long. The international rattan trade dates back as far as the 1920's, when Ghana supplied a significant proportion to the UK market. Some raw cane has been recently exported from Ghana and Nigeria to Korea. Currently, the international trade in rattan is worth about US$ 6.5 billion a year, but the international trade is dominated by South-East Asian countries. (PROTA4U) Properties: The stem is reddish brown and is of light to medium weight with a density of 400–600 kg/m³ when oven-dry. It is valued because of its strength, durability, bending ability and aesthetic value. At 12% moisture content stems from Nigeria had a modulus of rupture of 91 N/mm² and a modulus of elasticity of 11,100 N/mm². It is common to see cracks on the stem surface. These cracks, which are areas of insipient structural failure, are attributed to different drying rates of the core and the outer portions. Furthermore, radial swelling and shrinking is higher than longitudinal swelling and shrinking, which may cause stresses within the cane leading to cracks and warping. The stems are susceptible to discoloration by fungi, while beetles may make holes. The most common cause of staining are blue stain fungi. It is estimated that about 20% of harvested canes become stained if not treated. Fungal invasion can occur within one day of cutting. Staining can be controlled by spraying or soaking in preservative solution, but prophylactic treatment is seldom applied within 24 hours as required because of difficulties posed by harvesting procedures, storage and transport. Through intensive marketing, furniture in various colours has become fashionable. However, heavily stained material cannot be used for furniture since its bending strength is reduced; it is often utilized for baskets and other perishable products, or even as fuel. Poles can also be discoloured by surface moulds if transported or stored under humid conditions. Unlike blue stain, this discoloration is only superficial and can be wiped off. Nevertheless, the surface shine is reduced. At moisture levels of more than 20%, decay fungi can also attack the stem. Such infections are often noticed only at a later stage, when the fruit bodies appear, and they can cause serious structural degradation of rattan in service. Air-dried samples of the stems in Nigeria were recorded to contain per 100 g: water 15.8 g, energy 1359 kJ (325 kcal), protein 2.9 g, fat 0.8 g, carbohydrate 79.4 g, ash 1.0 g, Ca 212 mg, Mg 35 mg. (PROTA4U) Diseases and pests: Laccosperma secundiflorum is susceptible to attacks by fungi and insects due to its high starch content. Defects resulting from these attacks can result in severe losses. (PROTA4U) Laccosperma secundiflorum is harvested exclusively from the wild. Usually cutting of all the stems within a clump prevents juvenile ones from growing successfully, since their survival depends on the mature stems in the middle of the clumps. To ensure sustainability, only mature stems should be removed and adequate light should be made available to the juvenile ones to ensure vigorous regeneration. Where some level of management of wild Laccosperma secundiflorum is implemented, the cut stems are almost totally removed to deliberately allow adequate light penetration for regeneration of the clump. The same clump can then be harvested again 3–5 years later. Some clumps are known to have been harvested more than 4 times. In on-farm trials in Ghana, Nigeria and Cameroon high post planting mortalities were recorded, which were attributed to neglect and predation by rodents. However, the growth rates reported in established plantings in West Africa were encouraging, which indicates that, once past the establishment phase, Laccosperma secundiflorum can be grown in a relatively short cropping cycle. (PROTA4U) Harvesting: From each rattan clump, harvesters tend to cut only the mature canes; young stems are often left and can be harvested during a later visit. The stems selected are those with no lower leaves, and often only the lower 6 m (2 lengths of cane) are harvested. This is because living nodes form a considerable obstruction when the cane is split. So, the remaining 30 m of each mature stem is left in the canopy, and previously harvested rattan clumps are often marked by the presence of many dry stems in the canopy. The major disadvantage of this harvesting procedure is that, with the top sections of the cut stems remaining in place, there is little light penetration to the clump. This often means that the rhizome will not regenerate, and the clump often dies. In some communities improved harvesting is practiced, mainly with the aim of encouraging regeneration after harvest. In this case, the main part of the cut stems is removed from the canopy to allow sufficient light to reach the rhizome. Harvesting of rattans is often an unpleasant and dangerous occupation with dead branches being dislodged from the canopy, as well as ants and wasps being disturbed. (PROTA4U) |
External Links
References
Phonetic spelling of Latin names by edric.
Special thanks to Geoff Stein, (Palmbob) for his hundreds of photos.
Special thanks to Palmweb.org, Dr. John Dransfield, Dr. Bill Baker & team, for their volumes of information and photos.
Glossary of Palm Terms; Based on the glossary in Dransfield, J., N.W. Uhl, C.B. Asmussen-Lange, W.J. Baker, M.M. Harley & C.E. Lewis. 2008. Genera Palmarum - Evolution and Classification of the Palms. Royal Botanic Gardens, Kew. All images copyright of the artists and photographers (see images for credits).
T.C.H Sunderland, A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae) in Phytotaxa 51. 2012
Many Special Thanks to Ed Vaile for his long hours of tireless editing and numerous contributions.