Pollen Analysis (pollen + analysis)

Distribution by Scientific Domains


Selected Abstracts


Palynological, physico-chemical and colour characterization of Moroccan honeys: I. River red gum (Eucalyptus camaldulensis Dehnh) honey

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 4 2003
Anass Terrab
Summary The melissopalynological, physico-chemical and colour characteristics of Eucalyptus honeys from Morocco were studied. It is generally accepted that a minimum content of 70% of Eucalyptus pollen is necessary to classify an Eucalyptus honey as unifloral. Twenty-eight physico-chemical and five colour parameters were measured, including the content of sugars and minerals, proline, water content, pH, acidity, hydroxymethylfurfural, diastase activity, ash, electrical conductivity, colour coordinates (L*, a*, b*), chroma (C*ab) and hue angle (hab). Pollen analysis was included, and samples contained a mean of six pollen types (range 2,12). The majority of the samples (75%) contained more than 90%Eucalyptus pollen. The presence of Quercus, Plantago and Thymelaea pollen allows the differentiation of these honeys from those with a different geographical origin. Physico-chemical analysis showed that there was a low percentage of sucrose ( = 0.01%) and trisaccharides. Mineral analysis showed a low percentage of Mg ( = 25.99 ppm) and K ( = 205 ppm), while electrical conductivity ( = 721 ,S cm,1) and diastase activity ( = 39.05 °Gothe) showed medium-high values. The colour parameters lightness (L*) and chroma (C*ab) showed relatively low values. [source]


Nectar and Pollen Sources for Honeybee (Apis cerana cerana Fabr.) in Qinglan Mangrove Area, Hainan Island, China

JOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 11 2006
Yi-Feng Yao
Abstract In the present study, nectar and pollen sources for honeybee (Apis cerana cerana Fabr.) were studied in Qinglan mangrove area, Hainan Island, China, based on microscopic analysis of honey and pollen load (corbicular and gut contents) from honeybees collected in October and November 2004. Qualitative and quantitative melittopalynological analysis of the natural honey sample showed that the honey is of unifloral type with Mimosa pudica L. (Mimosaceae) as the predominant (89.14%) source of nectar and pollen for A. cerana cerana in October. Members of Araceae are an important minor (3%-15%) pollen type, whereas those of Arecaceae are a minor (<3%) pollen type. Pollen grains of Nypa fruticans Wurmb., Rhizophora spp., Excoecaria agallocha L., Lumnitzera spp., Bruguiera spp., Kandelia candel Druce, and Ceriops tagal (Perr.) C. B. Rob. are among the notable mangrove taxa growing in Qinglan mangrove area recorded as minor taxa in the honey. The absolute pollen count (i.e. the number of pollen grains/10 g honey sample) suggests that the honey belongs to Group V (>1 000 000). Pollen analysis from the corbicular and gut contents of A. cerana cerana revealed the highest representation (95.60%) of members of Sonneratia spp. (Sonneratiaceae), followed by Bruguiera spp. (Rhizophoraceae), Euphorbiaceae, Poaceae, Fabaceae, Arecaceae, Araceae, Anacardiaceae, and Rubiaceae. Of these plants, those belonging to Sonneratia plants are the most important nectar and pollen sources for A. cerana cerana and are frequently foraged and pollinated by these bees in November. (Managing editor: Ya-Qin Han) [source]


Seasonality of modern pollen and sediment deposition in an estuarine context: the Severn Estuary Levels, southwest England,

JOURNAL OF QUATERNARY SCIENCE, Issue 3 2008
J. R. L. Allen
Abstract Recent sedimentological and palynological research on subfossil Holocene banded sediments from the Severn Estuary Levels suggested seasonality of deposition, registered by variations in mineral grain-size and pollen assemblages between different parts of the bands. Here we provide data that strengthen this interpretation from sampling of modern sediments and pollen deposition on an active mudflat and saltmarsh on the margin of the Severn Estuary, and comparison with a vegetation survey and contemporary records of climate, river and tidal regimes. The results of grain-size analysis indicate deposition of comparatively coarse-grained silts during the relatively cool and windy conditions of winter and comparatively fine-grained sediments during relatively warm and calm summer months. Pollen analysis demonstrates the significance of long-term storage of pollen grains and fern spores in the estuarine waterbody, superimposed on which seasonal variations in pollen inputs from local and regional vegetation remain detectable. Copyright © 2007 John Wiley & Sons, Ltd. [source]


Late Weichselian pollen stratigraphy, clay varve chronology and palaeomagnetic secular variations in Lake Bolmen, Småland, south Sweden

BOREAS, Issue 3 2001
JONAS ISING
Pollen analysis, glacial varve chronology and palaeomagnetic measurements were carried out on Late Weichselian lake sediments from southwestern Smaland, south Sweden. The sequence is correlated to the GRIP event stratigraphy, expressed in calendar years BP, and covers the period from the deglaciation at c. 14 400 to 11 300 calendar years BP. The series encompasses c. 930 varves and has been connected to the local varve chronology. Varve thickness increases markedly after the Older Dryas stadial, which indicates an accelerated deglaciation and melting of dead ice. The pollen diagram displays the vegetation development from the deglaciation at c. 14 400 calendar years BP to the transition to the Holocene. The vegetation succession starts with an arctic pioneer vegetation at the deglaciation, changes to a more stable tundra environment and displays a development which concurs with the traditional lateglacial pollen stratigraphy for southern Sweden. A palaeo-magnetic secular variation curve is presented displaying two westerly declination swings at 14200-13800 and 12 800-11 600 calendar years BP, respectively. The upper one can be recognized from other palaeomagnetic stratigraphies from southern Sweden and Estonia. [source]


A multi-proxy study of Holocene lake development, lake settlement and vegetation history in central Ireland,

JOURNAL OF QUATERNARY SCIENCE, Issue 2 2005
K. A. Selby
Abstract Stratigraphical investigations, geomorphological mapping, and diatom, plant macrofossil and pollen analyses were undertaken in and around two lakes in central Ireland to establish correlations between changes in lake conditions and catchment vegetation throughout the Holocene. Similar investigations of an adjacent mire reveal early Holocene changes in lake level and area. The palaeoecological data show high correlations related to variations in lake depth and area, catchment vegetation type, organic inputs and trophic status. Catchment-scale deforestation is gradual and occurs through the Bronze and the Iron Ages, and the construction of a crannog in the early Medieval period (seventh century AD) appears to be associated with a widespread increase in deforestation and mixed agriculture in the catchment. Both pollen and plant macrofossils suggest that one of the crannogs was used for crop storage in addition to domestic and any other activities. In the early to middle Holocene similarities in the proxy-data appear to be climatically driven through changing lake levels and areal extent whereas the later Holocene record is clearly dominated by anthropogenic changes within the catchment and the construction of crannogs in the lakes. The advantages of combining multi-proxy indicators of lake hydroecology with the vegetation record are illustrated. Copyright © 2005 John Wiley & Sons, Ltd. [source]


Little ice age alluvial fan development in Langedalen, western Norway

GEOGRAFISKA ANNALER SERIES A: PHYSICAL GEOGRAPHY, Issue 4 2001
Simon G. Lewis
This paper reports a preliminary investigation of the sedimentary succession in two alluvial fans in western Norway. Sedimentological information is supplemented by palaeoecological data from pollen analysis and the age of the sequence is constrained by six radiocarbon age estimates on woody fragments and peat. These data suggest that significant accumulation of fan sediments took place after AD 1637,1685. Before this, the fluvial landscape and the adjacent slopes may have been more stable with the development of Betula, Salix and Alnus woodland on the valley floor and sides. Although there is no indication of gradual climatic deterioration in the vegetation record from these sites, the radiocarbon chronology suggests that enhanced fan development was coincident with the climatic change associated with the ,Little Ice Age'. This was probably a response to glacier expansion and increased discharge and sediment supply to the alluvial fans from outlets of the Jostedalsbreen ice cap on the southern side of Langedalen. Initial response to climate change in this setting was therefore enhanced geomorphic activity and instability of the valley-side slopes. [source]


From ice age to modern: a record of landscape change in an Andean cloud forest

JOURNAL OF BIOGEOGRAPHY, Issue 9 2010
B. G. Valencia
Abstract Aim, To investigate the palaeoecological changes associated with the last ice age, subsequent deglaciation and human occupation of the central Andes. Location, Lake Pacucha, Peruvian Andes (13°36,26, S, 73°19,42, W; 3095 m elevation). Methods, Vegetation assemblages were reconstructed for the last 24 cal. kyr bp (thousand calibrated 14C years before present), based on pollen analysis of sediments from Lake Pacucha. An age model was established using 14C accelerator mass spectrometry dates on bulk sediment. Fossil pollen and sedimentological analyses followed standard methodologies. Results, Puna brava replaced the Andean forest at the elevation of Lake Pacucha at the Last Glacial Maximum (LGM). Deglaciation proceeded rapidly after 16 cal. kyr bp, and near-modern vegetation was established by c. 14 cal. kyr bp. The deglacial was marked by the range expansion of forest taxa as grassland taxa receded in importance. The mid-Holocene was marked by a lowered lake level but relatively unchanged vegetation. Quinoa and maize pollen were found in the latter half of the Holocene. Main conclusions, Temperatures were about 7,8 °C colder than present at this site during the LGM. The pattern of vegetation change was suggestive of microrefugial expansion rather than simple upslope migration. The mid-Holocene droughts were interrupted by rainfall events sufficiently frequent to allow vegetation to survive largely unchanged, despite lowering of the lake level. Human activity at the lake included a 5500-year history of quinoa cultivation and 3000 years of maize cultivation. [source]


The ,oriental' component of the Balkan flora: evidence of presence on the Thracian Plain during the Weichselian late-glacial

JOURNAL OF BIOGEOGRAPHY, Issue 5 2008
E. K. Magyari
Abstract Aim, To obtain palaeobotanical evidence enabling evaluation of the viability of the hypothesis that the ,oriental' element of the Balkan flora reached south-east Europe from Turkey prior to the Holocene, probably via the Thracian Plain during a late Quaternary glacial stage but no later than the late Weichselian. Location, Ezero wetland, northern Thracian Plain, Bulgaria. Methods, We undertook analyses of pollen and microspores, plant macrofossils, wood fragments and molluscs recovered from sediments deposited in the Ezero wetland during the late Weichselian and Weichselian late-glacial. Sediment chronology was determined using radiocarbon age estimates. Results, Six metres of sediments were recovered from the basin, of which the lower 3 m, extending from c. 15,450 cal yr bp to the early Allerød, was analysed. A major hiatus occurred after c. 13,900 cal yr bp, the overlying sediments being of late Holocene age. Palaeobotanical evidence indicates predominantly open vegetation during the Weichselian late-glacial, although macrofossil remains of woody taxa demonstrate the local presence of patches of wooded steppe and gallery forest. Changes in the composition of the steppe vegetation, and in the nature of the sediments deposited in the basin, indicate changes in climatic conditions, especially in the hydrological regime and in the moisture available to vegetation. After an initially relatively moister phase, the final centuries of the late Weichselian were drier, as was a short interval that may correlate with the Older Dryas. Moister conditions characterize intervals corresponding to the Bølling and Allerød sub-units of the Weichselian late-glacial interstadial. Although the pollen evidence is thus consistent with that from previous studies of this period in south-east Europe and south-west Asia, indicating predominantly open steppe vegetation, the macrofossil evidence indicates the persistent local presence of woody taxa. The woody taxa recorded include Celtis tournefortii -type and Juniperus cf. J. excelsa, two taxa today characteristic of the wooded steppes of Anatolia and members of the ,oriental' element of the southern Balkan flora, as well as Rosaceae Subfams. Maloideae and Prunoideae, Alnus and Fraxinus. Main conclusions, The late Weichselian vegetation of the northern Thracian Plain included patches of wooded steppe that supported members of the ,oriental' element of the modern Balkan flora. The presence of such taxa renders viable the hypothesis that they could have reached south-east Europe from Turkey via the Thracian Plain during glacial times. Such hypotheses in historical biogeography can be evaluated critically using the evidence obtained from plant macrofossil analyses in combination with that from pollen analysis. [source]


A reconstruction of the history of a Holocene sand dune on Great Barrier Island, northern New Zealand, using pollen and phytolith analyses

JOURNAL OF BIOGEOGRAPHY, Issue 6 2000
M. Horrocks
Abstract Aim, To reconstruct the history of a Holocene sand dune using pollen and phytolith analyses, and to identify the strengths, weaknesses and compatibility of these two methods in the interpretation of Quaternary coastal environments. Location, Great Barrier Island, northern New Zealand. Methods, Pollen and phytolith analyses were carried out on a sequence through a Holocene sand dune containing a palaeosol. Results, Phytoliths were present throughout the sequence. Grass phytoliths increased at the expense of tree phytoliths following fire disturbance. Pollen (and spores) was preserved only in the palaeosol part of the profile. Pteridium fern spores increased at the expense of tall tree pollen following the fire disturbance. Main conclusions, Lack of phytolith production by many species and problems of taxonomic specificity in many others restricts the usefulness of phytolith analysis to defining only broad vegetation types. In New Zealand, gymnosperms are invisible in the phytolith record and ferns are extremely under-represented. In contrast, pollen analysis usually provides a great deal of information regarding the composition of a particular vegetation type. The loss of microscopic charcoal fragments during the phytolith extraction process is a disadvantage in the reconstruction of environments where fires have occurred. The greater durability of phytoliths compared with pollen means that phytoliths may be found in sediments where pollen has not been preserved. The phytolith record may also provide evidence of wetter environments that are not apparent in the pollen record. Unlike grass pollen, which is widely dispersed and therefore blurs the spatial record, the presence of grass phytoliths in sediments indicates a local source. The simultaneous application of both methods potentially provides a powerful tool in ecological interpretation and the reconstruction of Quaternary coastal environments. [source]


Fresh insights into long-term changes in flora, vegetation, land use and soil erosion in the karstic environment of the Burren, western Ireland

JOURNAL OF ECOLOGY, Issue 5 2009
Ingo Feeser
Summary 1. ,The study focuses on species-rich, upland, heathy vegetation with arctic-alpine floristic affinities and Sesleria grasslands in the karstic Burren region, western Ireland. The investigations aimed at reconstructing the long-term development of these high conservation-value communities and the role of farming in their formation and long-term survival. 2. ,The methods used included pollen analysis and 14C-dating of short monoliths and investigation of grykes (fissures in karstic limestone) for evidence of soil erosion. Special attention was paid to fossil, coprophilous fungal spores as indicators of local grazing. The strong local character of the pollen records facilitated identification of inter-site differences as well as regional patterns. It is shown that open pine woodland characterized the Cappanawalla uplands between c. 1500 BC and 500 BC. It is proposed that such woodlands, with floristic affinities to Scandinavian open pine woodlands on calcareous soils, provided a suitable environment for the present-day, open heath vegetation with species such as Dryas octopetala, Arctostaphylos uva-ursi, Geranium sanguineum and Empetrum nigrum. 3. ,Burning of vegetation as a management tool was important in the uplands over most of the last two millennia. Firing seems to have ceased with the onset of more intensive grazing regimes in the 18th century. 4. ,Synthesis. Upland palaeoarchives, derived from shallow peaty deposits, show that the upland Burren supported mainly plagioclimax Corylus -dominated woody vegetation and grasslands from c. 1500 BC (beginning of present record), until possibly as late as the 17th century AD. In the uplands of the north-western Burren, open, species-rich pinewoods with hazel dominated. The northern-arctic elements in the present-day upland flora survived clearances, involving initially Pinus sylvestris (c. 500 BC) and subsequently Corylus avellana (c. AD 1600). Colluvial material retrieved from grykes supports the idea of considerable soil loss occurring as late as the first and early 2nd millennium AD. The investigations highlight the potential of upland palaeoarchives, consisting of short sequences, for elucidating vegetation and land-use dynamics in karstic environments such as the Burren. [source]


APPLICATION OF WLF AND ARRHENIUS KINETICS TO RHEOLOGY OF SELECTED DARK-COLORED HONEY

JOURNAL OF FOOD PROCESS ENGINEERING, Issue 5 2001
KAMAL I.M. AL-MALAH
ABSTRACT The rheological properties of Common Black Horehound, Globe Thistle, and Squill types of dark-colored Jordanian honey were examined. The types of honey used were identified via assessing the source of nectar using pollen analysis (Melissopalynology). The apparent viscosity, ,, was measured as a function of the shear rate, ,. In addition, the apparent viscosity was measured, at constant shear rate (6.12 s,1), as a function of shearing time. Newton's law of viscosity (i.e., ,=,,) was found to adequately (R2, 0.99) describe the flow behavior of honey samples. The apparent viscosity was found to decrease with temperature, and the temperature dependence of viscosity was contrasted versus both Arrhenius model (,=,oeEa/RT) and WLF model (,/,G= 10 (C1(T,T)/C2+(T,TG))). Although Arrhenius kinetics may fit the viscosity versus temperature data for the examined types of honey, nevertheless, it gives a relatively high value of activation energy that is quite comparable with, if not even larger than, that of a typical chemical reaction. On the other hand, WLF-model was found to adequately describe the data while at the same time it gives quite reasonable values of both TG and ,G, which are in agreement with those cited in literature. [source]


Bacterial ancient DNA as an indicator of human presence in the past: its correlation with palynological and archaeological data,

JOURNAL OF QUATERNARY SCIENCE, Issue 4 2009
Jacek Madeja
Abstract Palynological investigation is one of the most important tools for reconstructing past vegetation. Some plants have proved to be relatively sensitive indicators of human activity, but most of them are not specific. In this paper we propose a method which can be used for the verification of phases of anthropogenic impact on vegetation distinguished in pollen diagrams. In this work we adopted the existing molecular methods for tracking bacterial ancient DNA of Bifidobacterium and Bacteroides-Prevotella (known as human- and cow-specific genetic markers) in palynologically and archaeologically associated sediments. This method can be helpful in determining local human presence, especially in those time periods when pollen analysis has not always been very discriminating (Palaeolithic, Mesolithic) and at sites without archaeological evidence. Copyright © 2008 John Wiley & Sons, Ltd. [source]


Colour characteristics of honeys as influenced by pollen grain content: a multivariate study

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 4 2004
Anass Terrab
Abstract A chromatic analysis by tristimulus colorimetry and a pollen analysis (pollen grains contained in each honey sample, considering their volume and geometrical shape) were carried out on 33 Eucalyptus unifloral honeys; the colour of the pollen grains was also considered. Multiple linear regression (MLR) and partial least squares regression (PLSR) were used to establish equations relating the chromatic variables to the pollen data, ie number and morphology of the pollen grains, thus allowing the prediction of the ultimate colour from the botanical characteristics. The results obtained show that lightness (L*) is significantly (p < 0.05) related to the pollen type Olea europaea; on the other hand, the variable that better relates to the chroma is the Zea mays pollen type. Copyright © 2004 Society of Chemical Industry [source]


A long-term record of Quercus decline, logging and fires in a southern Swedish Fagus - Picea forest

JOURNAL OF VEGETATION SCIENCE, Issue 6 2002
Mats Niklasson
Tutin et al. (1964,1976) Abstract. We reconstructed forest development and disturbance events (fire and logging) during the last 1000 yr with tree-ring data, pollen and charcoal analysis from a semi-natural Fagus sylvatica-Picea abies forest (ca. 1 km2) in the hemiboreal zone. According to pollen analysis, Quercus robur together with Pinus sylvestris was abundant in the forest until the turn of the 18th/19th centuries when these species disappeared completely (Quercus) or nearly completely (Pinus) and were replaced by Fagus and Picea. The disappearance of Quercus was corroborated by the remarkable discovery of a single Quercus stump that had been cut in the 18th century and had become overgrown and preserved by a very old Picea. In total 11 fires were dated from 1555 to 1748 from fire scars in several Pinus stumps cut 100 - 200 yr ago. Since the last fire in 1748, no Quercus or Pinus have regenerated in the core of the reserve apart from single pines in neighbouring managed forest (80 yr ago). During the period of documented fires Fagus was protected from fires in a refuge made up of large boulders. Picea colonized the region at the time when the fires ceased 250 yr ago. We hypothesize that most of the fires were probably of human origin because of their patchiness and high frequency compared to the natural background levels of lightning ignitions in the region. On a 300-yr time scale, logging and fire suppression seem to strongly overshadow the effect of climate change on forest composition and dynamics. [source]


A multi-dating approach applied to proglacial sediments attributed to the Most Extensive Glaciation of the Swiss Alps

BOREAS, Issue 3 2010
ANDREAS DEHNERT
Dehnert, A., Preusser, F., Kramers, J. D., Akçar, N., Kubik, P. W., Reber, R. & Schlüchter, C. 2010: A multi-dating approach applied to proglacial sediments attributed to the Most Extensive Glaciation of the Swiss Alps. Boreas, Vol. 39, pp. 620,632. 10.1111/j.1502-3885.2010.00146.x. ISSN 0300-9483. The number and the timing of Quaternary glaciations of the Alps are poorly constrained and, in particular, the age of the Most Extensive Glaciation (MEG) in Switzerland remains controversial. This ice advance has previously been tentatively correlated with the Riss Glaciation of the classical alpine stratigraphy and with Marine Isotope Stage (MIS) 6 (186,127 ka). An alternative interpretation, based on pollen analysis and stratigraphic correlations, places the MEG further back in the Quaternary, with an age equivalent to MIS 12 (474,427 ka), or even older. To re-evaluate this issue in the Swiss glaciation history, a multi-dating approach was applied to proglacial deltaic ,Höhenschotter' deposits in locations outside the ice extent of the Last Glacial Maximum. Results of U/Th and luminescence dating suggest a correlation of the investigated deposits with MIS 6 and hence with the Riss Glaciation. Cosmogenic burial dating suffered from large measurement uncertainties and unusually high 26Al/10Be ratios and did not provide robust age estimates. [source]


Intriguing climatic shifts in a 90 kyr old lake record from northern Russia

BOREAS, Issue 1 2008
MONA HENRIKSEN
A 22 m long sediment core from Lake Yamozero on the Timan Ridge in northern Russia has provided evidence of intriguing climatic shifts during the last glacial cycle. An overall shallowing of the lake is reflected in the lower part of the cores, where pollen indicates a transition from glacial steppe vegetation to interstadial shrub-tundra. These beds are capped by a well-defined layer of compact clay deposited in relatively deep water, where pollen shows surrounding spruce forests and warmer-than-present summer temperatures. The most conservative interpretation is that this unit represents the last interglacial period. However, a series of Optical Stimulated Luminescence (OSL) dates suggests that it corresponds with the Early Weichselian Odderade interstadial (MIS 5a). This would imply that the Odderade interstadial was just as warm as a normal interglacial in this continental part of northern Europe. If correct, then pollen analysis, as a correlation tool, is less straightforward and the definition of an interglacial is more complex than previously thought. We discuss the validity and possible systematic errors of the OSL dates on which this age model is based, but conclude they really indicate a MIS 5a age for the warm period. Above the clay is an unconformity, most likely reflecting a period of subaerial exposure implying dry conditions. Deposition of silt under fluctuating cold climates in the Middle Weichselian continued until a second gap in the record at c. 40 kyr BP. The lake basin started to fill up again around 18 kyr BP. [source]


Cytogenetics of species of Chamaecrista (Leguminosae , Caesalpinioideae) native to southern Brazil

BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2006
ELAINE BIONDO
Chromosome numbers, karyotypes, meiotic behaviour and pollen analysis are presented for species of Chamaecrista Moench (Leguminosae, Caesalpinioideae, Cassieae) native to southern Brazil: C. nictitans ssp. patellaria, C. nictitans ssp. disadena, C. repens, C. rotundifolia, C. flexuosa, C. vestita and C. desvauxii. Meiotic behaviour is reported for the first time for all the taxa and was very regular; only bivalents were formed at diakinesis and metaphase I, chromosome disjunction and segregation were regular at anaphases I and II, meiotic indexes were over 99% and pollen fertility was over 92%. Pollen grains were subprolate in C. flexuosa and C. vestita and prolate,spheroidal in the other taxa. Karyotypes were symmetrical in all six species and the data are original, except for C. nictitans ssp. patellaria. Chromosome number is presented for the first time for C. repens (2n = 16) and has been confirmed for the other taxa: 2n = 14 for C. desvauxii, 2n = 32 for the tetraploid C. nictitans ssp. patellaria and C. nictitans ssp. disadena, and 2n = 16 for the other species. These two basic numbers found in the genus, x = 7 and x = 8, point to chromosome evolution by dysploidy, which has also been accompanied by polyploidy. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society, 2006, 150, 429,439. [source]