Palm Crowns Research Articles

Rhynchophorus palmarum

<i>Rhynchophorus palmarum</i>

Bud rot disease of coconut in relation to endemic spots in Kerala state, India

In India bud rot is quite common on the West and East Coast tracts. A random survey on bud rot disease of coconut, caused by Phytophthora palmivora But.l, carried out in Kasaragod, Kannur and Calicut districts of Kerala revealed that, there is correlation between the disease incidence and the location of the palms. The disease incidence was high in the hilly tracts when compared to that of the plains. Studies on the survival of P. palmivora propagules in nature revealed that the pathogen survives in the crown, soil and roots of healthy and diseased palms. However, the percentage of survival was high in the endemic areas-Mandapam (Kasaragod District), Josegiri (Kannur Dist.) and Kuttiadi (Kozhikode Dist.), both in the case of diseased and healthy palms compared to that of areas with lesser disease incidence. The temperature and humidity in the coconut growing tracts of hilly areas of Kasaragod, Kannur and Kozhikode districts are suitable for the survival of the pathogen in the crown during almost all months, resulting in the high frequency of disease incidence during monsoon season and continued infection up to January. Examination of the rain water collected from bud rot affected coconut gardens also indicated that the pathogen surviving in the crown debris can act as a source of inoculum, which spreads to the neighboring palms through rain splashes. Based on the weather data it is possible to predict the bud rot incidence well in advance.

Male aggregation pheromone of date palm fruit stalk borer Oryctes elegans.

Laboratory and field investigations were carried out to characterize the chemical communication system of the date palm fruit stalk borer, Oryctes elegans, and to develop pheromone-based trapping in Eastern Iran. Adults of both sexes feeding on date palm pieces attracted conspecifics, whereas date palm alone was minimally attractive. Males were twice as attractive as females. More beetles were captured at the palm crown than at ground level. Odors from adults feeding on sugarcane were sampled and analyzed by gas chromatography and mass spectrometry. Whereas females did not emit sex specific volatiles, males emitted a blend of 4-methyloctanoic acid (1: major component) and ethyl 4-methyloctanoate (2), occasionally mixed with minor components: 4-methyloctanyl acetate (3), methyl 4-methyloctanoate (4), 4-methyloctanol (5), and nonanyl acetate (6). Electroantennography and field trapping experiments demonstrated that compound 1 is an essential component of the male aggregation pheromone of O. elegans. It was barely attractive by itself but synergistic with fresh date palm odor. It attracted many more beetles than any of compounds 2-6. The addition of one or several of compounds 2-6 to 1 did not improve trap captures. During the course of 2 years, we captured 4000 beetles, with a weekly average of 6.3 beetles/trap, and were able to monitor the seasonal flight of O. elegans. Our results provide the basis for developing mass trapping for control of this pest.

Sampling Rhodnius neglectus in Mauritia flexuosa palm trees: a field study in the Brazilian savanna.

Two sampling methods (manual capture and live-baited adhesive traps) were compared for collecting the bug Rhodnius neglectus Lent (Hemiptera: Reduviidae: Triatominae) from palm trees, Mauritia flexuosa L. (Arecaceae), in the savanna of Brasília DF. R. neglectus was found in 19/50 (38%) of palm trees sampled. The detection rate was much higher by visual inspection and manual capture (18/50=36%) than by our trapping method (5/50=10%), although one tree was found to be positive by trapping but not by manual capture. Bugs collected manually were mostly (146/154=95%) found among the dead organic material in palm crowns. In combination, these sampling techniques are useful for quick detection of triatomine bug infestation in palm trees, especially in areas of high ecological value where the palms should not be cut and dissected, but arboreal Rhodnius are suspected to transmit enzootic Trypanosoma cruzi that might represent a risk of causing human cases of Chagas disease.

Seed dispersal, plant recruitment and spatial distribution of Martius (Arecaceae) in a remnant of Atlantic forest in northeast Brazil

Seed dispersal ecology of Bactris acanthocarpa Mart. (Arecaceae), an Atlantic forest understory palm, was investigated during two years as an attempt to test the following predictions: (i) seeds of Bactris are dispersed by mammals and large-gaped birds; (ii) Bactris benefits from seed dispersal in terms of seed predation avoidance, improvement of seed germination and seedling survival; and (iii) spatial distribution of adults is related to patterns of seed dispersal. The study was conducted at Dois Irmãos Reserve, a 387.4-ha reserve of Atlantic forest in northeastern Brazil (8º S–35º W). Black–rumped agoutis ( Dasyprocta prymnolopha ) and Guianan squirrels ( Sciurus aestuans ) were identified as the seed dispersers/predators, moving seeds short distances (< 4 m from parents) and at low rates (0.04-0.05 diaspore/palm/day). Pyrene burial prevented seed predation by vertebrates and reduced by half seed infestation by Scolytidae beetles. Only buried pyrenes germinated. Pyrene predation was not correlated with distance from conspecific adults. In contrast, early seedling mortality was higher near conspecific adults. Most adults (64%) had their nearest conspecific adult neighbour > 4 m away in contrast to 96% of seedlings that occurred concentrated within 4 m from adults (77% under the palm crowns). Here, we present evidence that spatial distribution of B. acanthocarpa is partly due to low rates of seed removal, short-distance seed dispersal by agoutis and squirrels, and early seedling mortality associated with presence of seedlings under palm crowns.

A review of the importance of spines for pejibaye heart-of-palm production

Commercial plantations of pejibaye ( Bactris gasipaes Kunth, Palmae) are expanding in tropical America to supply the heart-of-palm market. The heart-of-palm is a gourmet vegetable composed of the tender unexpanded leaves in the palm's crown. Both spiny and spineless germplasm is available to growers, but there are no clear data on the superiority of either. Comparisons made among populations, among progenies within populations or among alleles within progenies are of interest for different reasons. In Hawaii, the Yurimaguas population (93% spineless; Pampa Hermosa landrace) is superior in heart-of-palm weight at one site and the Benjamin Constant (BC) population (79% spineless; Putumayo landrace) at another. Within the BC population there is a tendency for spineless plants to be superior in heart weight at one site and spiny to be superior at another. Within BC progenies, spineless plants often have more off-shoots at both sites, but superiority of spineless or spiny in terms of relative growth rates, heart weight and total edible weight depends upon location and seldom exceeds 10%. Although these yield components have low heritabilities there is variation amenable to selection, so that selecting within spineless germplasm should provide gains similar to those for spiny germplasm. Which is better is not a biological question but must be answered based upon comparative costs (management of spiny plants costs marginally to much more) and availability of germplasm at a given location.

Ranging behaviour and habitat utilisation of the Malayan wood rat ( Rattus tiomanicus) in an oil palm plantation in Johore, Malaysia

The ranging behaviour and habitat utilisation of Rattus tiomanicus, a serious pest of plantation crops in Southeast Asia, was studied extensively for the first time using radio-telemetry in an oil palm estate in Johore, Malaysia. Range size calculated by the minimum convex polygon (MCP) method reached an asymptote after between 55 and 70 telemetry fixes for both sexes. MCP estimates of the range sizes of R. tiomanicus males (mean 1696 m 2, SE ± 491.6, n = 6) and females (mean 390 m 2, SE ± 72.3, n = 6) differed significantly ( t = 2.634, P = 0.045). The ranges of perforate females (mean 504 m 2, SE ± 113.3, n = 3) were larger than those of lactating females (mean 275 m 2, SE ± 12.5, n = 3) but the difference was not significant, probably because of the small sizes of the samples. Range sizes, particularly of males, were substantially larger when estimated in this study by radio-telemetry than when examined by previous authors using the capture-mark-recapture procedure. Habitat utilisation was studied by recording the occupancy of the following habitat elements at the time of a fix: burrows, palm crowns, ground vegetation, inter-row frond piles. A total of 49.6% of all radio fixes of rats were made in the frond piles. This element of the oil palm habitat was probably used both as a site for nest construction and for moving around protected, to some extent, from predation. The remaining fixes occurred almost equally among the other three elements, which were used for resting (mainly burrows and tree crowns), feeding (vegetation and tree crowns) and moving about the habitat (vegetation). These observations are discussed in relation to the design of experiments to test rat control measures in oil palm plantings and the practical control of R. tiomanicus in this crop.

Development of a Sampling Method for First Instar Oiketicus kirbyi (Lepidoptera: Psychidae) in Oil Palm Plantations

The current study was conducted to develop a cost-effective and reliable method to estimate population densities of 1st-instar bagworms, Oiketicus kirbyi (Guilding), in Costa Rican oil palm plantations. Total numbers of larvae per tree were correlated with numbers on 80, 160, 240, or all (320-360) folioles of all palm leaves. The r 2 values of these correlations were used to assess the accuracy of population estimates obtained by sampling leaves in different positions within the palm crown or different numbers of folioles per leaf. Larvae were most abundant on apical and subapical folioles of leaves in the upper palm crown. When a limited number of folioles per leaf (80, 160, or 240) was sampled, leaves in the upper crown provided the most accurate estimates of larval densities per tree. Decreasing accuracy of population estimates from upper to lower leaves resulted from increasing variability of larval proportions from upper to lower leaves. Larval populations of 2 other oil palm defoliators, Opsiphanes cassina (Felder), and Stenoma cecropia (Meyrick), are currently assessed by sampling leaf 17. Sampling O. kirbyi larvae on 160 folioles of leaf 17, in the middle palm crown, may represent an acceptable compromise among cost-efficiency, reliability, and simultaneous assessments of several defoliating caterpillars. Reasonably accurate estimates of larval densities per area obtained in this study by sampling 1 palm per hectare should not be interpreted as a general recommendation for sample size, because the effect of population density on optimal sample size per hectare remains yet to be investigated.

Pupation site and emergence time influence the mating success of bagworm females, Oiketicus kirbyi

AbstractIn commercial oil palm plantations in Costa Rica, we tested the hypotheses that pupation site and emergence time affect the mating success of protogynous female bagworms, Oiketicus kirbyi (Guilding) (Lepidoptera: Psychidae). Greater proportions of female than male pupae on upper leaves of oil palms and greater proportions of mated females in the upper rather than lower crown strata support the hypothesis that selection of pupation site by female larvae influences the mating success of adults. Increasing captures of males with increasing trap height further suggest that enhanced mating success of females in tree tops may be attributed either to most effective dissemination of sex pheromone on higher sites, or to males foraging predominantly in the upper strata of oil palms. As the majority of females pupated in the middle rather than upper crown of oil palms, selection of pupation site by females may be affected by additional as yet unknown factors. Emergence of females significantly preceded emergence of males. Increasing proportions of mated females throughout the emergence season probably resulted from an increased ‘availability’ of males. In tropical rainforests with local variations in O. kirbyi developmental time and stage, protogyny may represent an evolutionary strategy that furthers outbreeding.

Leaf Maturity, a Critical Factor in Embryogenesis

The embryogenic capacity of leaf explants was found to be related to their physiological maturity in young palms of Cocos nucifera. Leaf tissues from 12- to 24-month-old palms were embryogenic but the potential was quickly lost with the onset of juvenility. Even in young palms, explants of tender leaves responded differently according to their maturity. Only a particular leaf in a particular state produces embryogenic cells: the leaf whose growth was observed to increase by about 13 times its initial size in 1 month. It may be concluded that a crucial factor(s) determining embryogenesis in vitro is elaborated at a certain physiological stage of maturity of one particular leaf in the crown of a young palm. Furthermore, only a portion of this leaf yields embryogenic explants and its competence is of short duration.

Nidification of the Chestnut Forest-Rail Rallina rubra (Rallidae) in Papua New Guinea and a Review of Rallina Nesting Biology

SummaryFrith, C.B. & Frith, D.W. (1990). Nidification of the Chestnut Forest-Rail Rallina rubra (Rallidae) in Papua New Guinea and a review of Rallina nesting biology. Emu 90, 254–259.Nests, eggs and chicks of the Chestnut Forest-Rail Rallina rubra are described for the first time, from Tari Gap, Southern Highlands Province, Papua New Guinea. The nest is a large globular or domed structure of moss, leaves and ferns with a side entrance, typically placed some 2 m high in a pandanus palm crown (n = 20). The clutch is a single egg, unlike other rail clutches, and the egg is very large, being proportionately greater in mass to the bird than in any other rail so documented. Both sexes incubate but eggs are often left to become cold. Incubation in one nest was at least 34–37 days, being much longer than the incubation period of the only congener or of any other rail known. Nesting biology of Rallina spp. is reviewed.

Tent-roosting by Scotophilus kuhlii (Chiroptera: Vespertilionidae) in the Philippines

A number of bats are known to use modified leaves or 'tents' as daytime roosting sites. This behaviour has been reported for 14 species of phyllostomids in the genera Artibeus, Ectophylla, Mesophylla, Uroderma, and Vampyressa (Brooke 1987, Timm 1987), and two species in the pteropodid genus Cynopterus (Goodwin 1979, Phillips 1924, Sandhu 1984). Here we report tentroosting by the Oriental house bat, Scotophilus kuhlii Leach (= S. temminckii (Horsfield)), in the Philippines. This is the first record of such behaviour for a vespertilionid. On the evening of 20 May 1987, on the campus of Ateneo de Manila University, Quezon City, Luzon Island (140 38' N, 1210 3' E; elev. 50 m) we observed several large microchiropterans emerging from the crown of a fan palm, Livistona rotundifolia (Lam.) Mart. The palm was about 12 m in height, and had approximately 35 mature fronds. It was located at the edge of a grassy lawn at the top of a fairly steep slope. Surrounding vegetation consisted of shrubs and small trees. The crown was in the open and conspicuously higher than most of the surrounding vegetation or buildings. Subsequent examination of the crown with binoculars during the day revealed that many of the older fronds had been modified to form tents (Figure 1). A number of microchiropteran bats were observed roosting under two of the modified fronds. Several other fronds may also have sheltered bats, but were too tightly folded for visual confirmation. Three tents were clearly unoccupied. Fifteen to twenty Scotophilus kuhlii were flushed from one of the

Ants (Hymenoptera: Formicidae) as egg predators of coconut pests, especially in relation to biological control of the coconut caterpillar, Opisina arenosella Walker (Lepidoptera: Xyloryctidae), in Sri Lanka

AbstractA study was made of ants in Sri Lankan coconut plantations, especially of species foraging and nesting in palm crowns. At least 11 species were found nesting in the spadices, and a special study was made of interactions between some likely to be insect egg predators or to interfere with predation. Oecophylla smaragdina (F.) and Paratrechina longicornis (Latreille) were mutually exclusive, but some non-dominant species such as Monomorium spp. commonly nested and foraged in palms occupied by large populations of dominants such as O. smaragdina and Crematogaster sp. Eggs of the coconut pest Opisina arenosella Walker (and of Corcyra cephalonica (Stainton), which were used to simulate the former on palm fronds) were rapidly found and removed by certain ant species, notably M. floricola (Jerdan) and Crematogaster sp. Oecophylla smaragdina and P. longicornis seemed erratic as egg predators. Surveys of ants in areas where Opisina arenosella does, and does not, develop to outbreak populations showed that Monomorium spp. in particular were notably more common in the non-outbreak areas. However, other ants, notably Technomyrmex albipes (F. Smith), were sometimes common in outbreak areas and were seemingly good egg predators. The presence of thriving Oecophylla smaragdina colonies on currently attacked palms shows that this otherwise well-recognized predator has little or no effect on Opisina arenosella. It is concluded that several species of ants which nest in coconut palm crowns probably contribute importantly to the mortality of eggs of O. arenosella and help keep it in its rare endemic state in most places most of the time, even in outbreak areas.

STRANGLER FIG ROOTING HABITS AND NUTRIENT RELATIONS IN THE LLANOS OF VENEZUELA

The strangler figs, Ficus pertusa and F. trigonata, are abundant in the seasonally flooded palm savanna (llanos intermedio) near Calabozo, Venezuela. The most common host tree for the hemiepiphytic figs is the palm Copernicia tectorum; nearly half of the palms support either an epiphytic or a ground‐rooted fig. During their epiphytic stage the figs are rooted behind the palms' marcescent leaf bases. Material trapped behind the leaf bases is higher in organic matter, nitrogen, magnesium, and potassium than soil from the ground near the palms. The suggestion that nutrient availability to epiphytes is high is supported by the observation that concentrations of several nutrients, including N, P, and K, are significantly higher in epiphytic leaves than in tree leaves. Figs retain access to the epiphytic medium by producing upwardly growing (apogeotropic) roots that remain attached in the host palm's crown long after the fig has become firmly rooted in the ground. Although upward growing roots are expected to be more important in nutrient than water uptake, there are no obvious differences in the xylem anatomy of upward and downward growing fig roots. Terrestrial roots of fig trees are generally infected with vesicular‐arbuscular mycorrhizae, but the epiphytic roots of the same individuals are not infected.

Association of coconut foliar spirality with latitude

The leaves of the coconut palm (Cocos nucifera t.) are arranged in five clear spirals. ~11 of which, in a tree, progress either clockwisely (left-handed) or counter-clockwisely (right-handed) (Fig.1). The phyllotaxy of the coconut is alternate and any two consecutive leaves subtend an angle which is approximately equal to the Fibonacci angle (137.5 degrees). Such an arrangement results in the manifestation of foliar spirals. The number of spirals in any palm species is always a Fibonacci number (Davis,1970). The association of phyllotaxy with Fibonacci numbers has received the attention of investigators over a long period (Braun,1831; Church,l920; Richards,l950; Snow,1955; Adler,1974; Mitchison,l977). The schematic representation shown in figure 2 depicts a palm crown bearing 43 leaves. The smaller angle between leaves 1 and 2, or between any two consecutive leaves, is 137.5 degrees. When leaves 1,6,11,16,21,.... (i.e. every fifth leaf) are joined by a smooth curve, a spiral which corresponds to one of the five spirals of a coconut crown, becomes obvious. In this drawing all the five spirals veer counter-clockwisely from the periphery towards the growing point. It may be noted that five right spirals will be discernible in a crown where the spiral formed by consecutive leaves (the genetic spiral) is clockwise. Where the genetic spiral is counter-clockwise, the five spirals progress to the left (Davis,l971). In Fig.2 the eight spirals move clockwisely, opposite to the set of five spirals. These eight spirals represent those seen in the crown of the African oil palm (.Elaeis quineensis, Jaca. 1. Here the direction of the eight spirals and that of the genetic spiral are the same. The numbers 5 and 8 are consecutive terms of the Fibopacci sequence (1,1,2,3,5,8,13,21,34,....). Starting from the single genetic spiral shown in the diagram, it is possible to trace several other sets of spirals such as 2,3,5,8,13,21 and so on. If the terms of the Fibonacci sequence are numbered serially, the sets of spirals representing the odd-numbered terms will appear to progress clockwisely and those representing the even-numbered terms will move counter-clockwisely. Thus, the sets of 5 and 8 spirals veer opposite to each other. For this reason the five spirals of the coconut and its genetic spiral move in opposite directions whereas the eight spirals of the oil palm and its genetic spiral progress in the same direction. Handedness of the coconut, in this communication, refers to the direction of the five foliar spirals.

The rhinoceros beetle project: History and review of the research programme

An account is given of the history and the results achieved by the U.N.D.P./S.P.C. Rhinoceros Beetle Project in the South Pacific. The special features of the rhinoceros beetle coconut palm system are reviewed as they influence and determine the research methods and the possibilities for pest control. The beetles' habit of burrowing into breeding sites and into the coconut palm crown, together with the low value of the crop precludes the use of insecticides for control. Biological control agents must be able to penetrate these living places in order to be successful. The success of the Project is attributed to the discovery and use of a baculovirus. Its success of the Project is attributed to the discovery and use of a baculovirus. Its success in reducing beetle numbers preceded the research on its ecology and safety and also curtailed other research directions. The virus is supported in integrated pest management programmes by the fungus Metarrhizium anisopliae and by plantation sanitation.

A population study of the coconut pest Segestidea uniformis (Willemse) (Orthoptera: Tettigoniidae) on an equatorial island

AbstractA population of the coconut pest Segestidea uniformis (Willemse) was monitored on a small island 2° from the equator in Papua New Guinea between 1973 and 1978. Totals of 54 000 first-instar nymphs were caught on sticky traps on palm trunks and 8750 other nymphs and adults were recovered from the crowns of palms. Generations were completely overlapping, and there was no evidence of seasonality in population fluctuations. The sex ratio was 50:50 in the first six instars, but 90% of seventh instars and 30% of adults were female. Explanations for these variations are given. The population declined from an annual mean of 24 individuals of all ages per palm crown in 1973 to 9 in 1976 and increased again to 29 in 1978. Most post-hatching mortality occurred as first instars climbed from the ground to the crown of palms, probably due to the lizard Gehyra oceanica and rainfall. The number of adults was more sensitive to mortality occurring after the first instars had arrived in the crowns. This mortality appeared to be related to the duration of periods without rainfall, supporting earlier observations that damaging outbreaks of S. uniformis populations do not occur in places which experience a regular dry season. Production of coconuts appeared to be inversely related to the population density of S. uniformis, which did not rise above a level estimated to cause 20% defoliation of the palms during the study. Nut production also seemed to be related to the number of hours of sunshine received in the preceding 12 months. Biological control aimed at nymphs and adults in palm crowns is suggested as an option for controlling S. uniformis which deserves investigation.

Chagas' disease in the Amazon basin III. Ecotopes of ten triatomine bug species (Hemiptera: Reduviidae) from the vicinity of Belém, Pará State, Brazil.

Tracking mammals to their nests or refuges, microhabitat dissection, light traps and surveillance of human dwellings were employed to identify sylvatic triatomine species and their natural ecotopes in the vicinity of Belem, Para State, Brazil. Ten species were found: Rhodnius pictipes, R. robustus, R. paraensis, Panstrongylus lignarius, P. geniculatus, P. rufotuberculatus, Eratyrus timeronatus, Microtriatoma trinidadensis, Belminus herreri and Triatoma rubrofasciata . All species except P. rufotuberculatus (only 1 specimen examined), B. herreri and T. rurofasciata were infected with Trypanosoma cruzi; Triatoma rubrofasciata was infected with Trypanosoma conorrhini . Natural ecotopes were defined principally in terms of specific habitats, such as burrows and hollow logs ( P. geniculatus ), palm crowns ( R. pictipes, R. robustus ), large hollow trees ( E. mucronatus, P. lignarius nymphs), small arboreal cavities ( P. lignarius, R. paraensis ), folded leaves within nests ( M. trinidadensis ), beneath loose tree bark ( B. herreri ), and inside buildings ( T. rubrofasciata ). Only species showed signs of obligate dependence on particular hosts. E. mucronatus was extraordinary in that nymphs fed on invertebrates in nature, as well as on the porcupine Coendou prehensilis . All species except P. geniculatus and M. trinidadensis could be maintained experimentally. R. pictipes and T. rubrofasciata commonly invaded houses, while P. geniculatus and P. lignarius occasionally did so. R. pictipes bugs entering houses were usually heavily infected with T. cruzi . Light-attracted sylvatic R. pictipes , originating from heavily infested mucaja palms ( Acrocomia sclerocarpa ), were considered the primary source locally sporadic and acute suburban cases of Chagas' disease. The incursion of domestic vectors into the Amazon basin from known endemic areas is considered to threaten the region with endemic Chagas' disease. Specific suggestions are given for measures to prevent both new sporadic cases of sylvatic origin and emergent endemic foci.

Rat Damage to Coconuts in Fiji. Part II Efficiency and Economics of Damage Reduction Methods

Abstract The effectiveness and economics of two commonly recommended methods of reducing rat damage to coconuts were examined. Three replicated trials were used to investigate the effectiveness of a 30 cm wide aluminium band placed around the palm trunk 3.5-4.5 m from the ground. On palms only 9–10 m high these bands did not effectively reduce rat damage as senile fronds frequently bridged the bands, providing rats with access to the palm crowns. Bands did prevent damage on tall palms (over 15 m) since no bridging by fronds occurred. A poison trial indicated that rat damage could be almost eliminated in a mature plantation for up to three months following one application of 3 kg/ha warfarin bait. This confirmed work carried out in Jamaica and the Gilbert and Ellice Islands. The cost of control by the two methods was assessed in relation to four copra values and it was concluded, in view of the relatively low levels of rat damage that prevailed, that neither form of control would be worthwhile until the value of copra exceeds F$150 per tonne and in the case of banding would only apply in the limited number of situations where bands are really efficient.

FIBONACCI NUMBERS FOR PALM FOLIAR SPIRALS

SUMMARY The Fibonacci sequence (1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144 …) formulated by the Italian mathematician, Leonardo da Pisa has many interesting mathematical properties. One of these is the fairly constant proportion that works out between any two consecutive stages in the sequence excluding, of course, some lower stages. Such a proportion, spoken of as Golden Proportion, exists in many plant species having alternate phyllotaxis. The foliar arrangement in a few species of palms has been critically studied with a view to understanding the mathematics underlying it. Palms display one, two, three, five, eight, or thirteen foliar spirals, and the spirals in a palm may move clockwisely or counter-clockwisely, each species having both types of palms in almost equal proportions. Areca catechu, Arenga pinnata, Borassus flabellifer, Cocos nucifera, Elaeis guineensis, Phoenix canariensis respectively are examples for the above foliar spiral categories. All these numbers synchronise the Fibonacci Numbers, and no palm is known to have foliar spirals numbering 4, 6, 7, 9, 10, 11 or 12. Exceptional species, however, do not show any clear spirals, but their leaves are arranged vertically in two, three, five or eight rows, the numbers again synchronising the Fibonacci stages. A model has been suggested for the arrangement of leaves in any palm crown in which two consecutive leaves have been shown to subtend 137.5 ° between them, and so this angle makes a proportion of 0.618 with the remaining angle (222.5 °) to complete one full revolution. It is this Golden Proportion that is responsible for palm leaves appearing in spirals. An explanation is offered for the apparent reversed situations in the positions of the flower-bunches in the coconuts (in left- and right-spiralled palms) and in the African oil palm. The drawing was prepared by Mr. S. K. De, the Senior Technical Assistant of the above Institute.