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Because the Gulf Coast Lower Cretaceous is dated by ammonites, it has great potential as a reference section for correlating continental sequences such as the Potomac Group and dating events in the rise of angiosperms. Middle Albian terrestrial palynofloras from Oklahoma have been described in detail, but the early Albian interval, represented in the Glen Rose Formation of Texas, is less well known. Samples from two localities on the Paluxy River, which correlate with horizons containing late early Albian ammonites, are dominated by Classopollis and Exesipollenites, but angiosperm pollen is the next most common terrestrial element, and there are several index spore species for Zone II in the Potomac Group. Among the angiosperms, reticulate monosulcates are most common and diverse, but there are also several tricolpate species. Stratigraphically important angiosperms include the Clavatipollenites rotundus group and reticulate tricolpates, which appear in the upper part of Potomac Zone I and the dated earliest Albian of England and Portugal. However, there are also tricolpates with striate-reticulate sculpture, a pollen type that is not known from upper Zone I but appears in the late early Albian of Portugal. This assemblage contrasts with floras from Potomac Zone II and the middle Albian (lower Fredericksburg Group) of Oklahoma, where tricolpates overtook monosulcate angiosperms in species diversity. These results confirm arguments based on the Portuguese section that there is a significant hiatus between Potomac Zones I and II, and that this gap is at least partly late early Albian. The dominance of Classopollis and Exesipollenites and the occurrence of isolated Northern Gondwanan elements (Sergipea, Tucanopollis) suggest that Texas lay in a transition zone between Southern Laurasia and the hotter and drier Northern Gondwana province, but regional studies are needed to disentangle geographic and climatic factors from effects of the lagoonal local environment.
This work presents the first description of a palynological assemblage preserved in sediments deposited in a saline lake (salina) in the Nhecolândia area of the Brazilian Pantanal. Pollen studies from salinas have been underappreciated due to inferred taphonomic issues related to elevated alkalinity. We have found a well-preserved assemblage that allowed the reconstruction of the history of local vegetation. Radiocarbon dating revealed a constant deposition since ∼3760 calibrated years before present (cal yrs BP), and pollen analyses suggested two main phases of vegetation and environmental development. From 3760 to 1510 cal yrs BP, the site was a swamp to shallow lake dominated by cattails (Typha domingensis) and Poaceae. From 1510 cal yrs BP to the present the herbaceous community is enriched with Cyperaceae and Bromeliaceae, and with tree taxa such as the Arecaceae (palm trees), evidencing the local development of a fringe vegetation. These two phases were interpreted as a change from drier to wetter settings, largely in agreement with regional lake and speleothem records, as well as pollen and carbon isotope studies from other locations in central South America during the latest Holocene. Given that salinas are non-floodable and pollen was found to be well preserved, we highlight the potential of palaeopalynology in these environments as a source of palaeoecological information for the Pantanal Basin.
Thirty-five surface sediment samples from three glacial sites – [Chorabari Glacier (Kedarnath), Hamtah and Chhatru glaciers (Lahaul-Spiti)] – situated in the western Himalaya, India, were palynologically analysed to explore the relationship between the modern pollen assemblages and the extant vegetation. The Chorabari Glacier is located in the Greater Himalaya and influenced by the Southwest Summer Monsoon; whereas the Hamtah and Chhatru glaciers are located in the Trans-Himalaya and affected more by the Western Disturbances (winter precipitation). The area around Chorabari Glacier receives abundant rainfall, while the Hamtah and Chhatru glaciers are in a high-altitude cold desert. Palynological studies have revealed an overwhelming dominance of Pinus pollen in all the samples. Though the sampling sites are 2 to 8 km away from the treeline and characterised by herbaceous ground vegetation, the marked predominance of arboreal pollen (especially Pinus) in the sediments stresses the importance of a proper interpretation of modern pollen data, so as to have an appropriate standard for deciphering the pollen–vegetation relationship in the respective study areas.
Actinostachys is a genus of the Schizaeaceae with two species reported from America: A. pennula and A. subtrijuga. The spores of the two species are studied using light microscopy, scanning electron microscopy and transmission electron microscopy. The spores are monolete, the equatorial diameter is 46–84 µm and the polar diameter is 26–50 µm. In A. pennula the ornamentation of the spores is foveolate and in A. subtrijuga it is striate, composed by parallel ridges separated by ornamented grooves. In both species, the exospore is two-layered and it is the wall that constitutes the ornamentation of the spores. The perispore is two-layered and thin with granules, and covers the outer surfaces of the exospore including the foveolae. On the spore surface of both species, abundant spheroids are observed. The ultrastructural analysis reveals that some of them are spherules and others globules. The studied species can be easily identified by their spores analysed with light microscopy even without prior treatment. We recommend that the spore ornamentation be included in dichotomous keys and descriptions of Actinostachys. The sporoderm ultrastructure of the species is described for the first time. The results contribute to the identification of the species and also may be valuable characters for systematic and phylogenetic purposes.
Dispersed spores interpreted as deriving from the earliest land plants have complex configurations (e.g. permanent dyads and permanent tetrads) and are readily distinguished from the more familiar trilete spores that often dominate post-Late Silurian dispersed spore assemblages. These forms occur mainly from the Middle Ordovician to Early Devonian. They were first recognised in 1971, but it was not until 1979 that the process of formal description commenced. In 1984 they were included in a newly created higher taxonomic grouping called ‘cryptospores’, the term reflecting their complex morphology and then the ongoing debate regarding their affinities. Subsequently the exact definition of the term cryptospore has been debated, with some preferring a wide definition encompassing all non-marine palynomorphs produced by algae and early land plants, but others confining inclusion to spores deriving from early embryophytes. Since their recognition, numerous ‘cryptospore’ taxa have been described. However, their complex morphologies are difficult to interpret and numerous taxonomic debates have confused the delineation of genera and their classification into higher ranks. Here we present a key for the identification of ‘cryptospore’ taxa with the aim of clarifying some of this confusion.
This paper presents the results of pollen and spore concentration of yellow drops in the Lucknow environs during the summer of 2014. The yellow spots were procured from the surface of a number of leaves and other objects from three different localities of Lucknow District of Uttar Pradesh. The size and shapes of these spots vary, ranging from linear to circular. Pollen grains recovered in good frequencies chiefly belong to angiosperms, whereas some gymnosperm pollen was also observed in trace frequencies. Other microbiota include fern spores, fungal remains and insect body parts in lower values. The study broadly suggests that palynomorphs recovered from yellow droppings are not fully airborne; rather, they are the types that honey bees gather from crop fields to feed their young. Brassica campestris and Asteroideae are the dominant plant taxa recorded in yellow rain samples. On investigation, it was noticed that yellow drop falling occurred for a few minutes on limited days during the summer of 2014, when the atmosphere experienced optimal temperature conditions with relatively humid environs. The observation also confirms that the yellow spots are nothing but faecal droppings, as suggested by the bee faeces theory which proposed that the origin of yellow rain is a phenomenon of nature. The study, in addition to aiding in understanding yellow rain occurrence, could also be helpful in aerobiological research, especially in examining the allergenicity of various pollen grains/spores in the area of investigation, causing bronchial asthma, hay fever (allergic rhinitis/pollinosis), nasobronchial allergy and other respiratory disorders along with conjunctivitis, contact dermatitis, eczema, food allergies and other health ailments. A multivariate principal component analysis (PCA) was applied to quantified data obtained from pollen frequency analyses of different areas of Lucknow, which clearly revealed a significant group variation in vegetation type on the basis of dispersal and deposition of pollen in yellow spots.
The Adana Basin is one of the major Neogene basins situated in SW Turkey with sedimentary successions providing good records of the paleoenvironmental changes that affected the Mediterranean area. Since a detailed biochronostratigraphic framework has not been properly established in the Adana Basin yet, this study will be the first multidisciplinary approach carried out in this region. In addition, a detailed biozonation based on marine palynomorphs was the first ever documented from the Köpekli Formation deposited during the Miocene (from late Burdigalian to Langhian) and the established biozones were correlated with those of planktonic foraminifera and calcareous nannofossils. According to the first occurrences (FOs) and the last occurrences (LOs) of selected taxa, five biozones (P-1, P-2, P-3, P-4 and P-5) based on dinoflagellate cysts; five biozones (M4a, M4b, M5a, M5b and M6) based on planktonic foraminifera; and two biozones (NN4 and NN5) based on calcareous nannofossils were established in the Miocene Köpekli Formation. In order to achieve a worldwide biostratigraphic perspective based on dinoflagellate cysts, the present biozones were compared with those described from NW Europe (Denmark, Germany, the Netherlands), the East Coast of the US and Egypt. After calibration to the established Turkish foraminifera and nannofossils standard, the palynological analysis shows that the recorded dinoflagellate cysts events (e.g. FO of Labyrinthodinium truncatum, Cerebrocysta poulsenii and Unipontidinium aquaeductus and LO of Palaeocystodinium ventricosum) occurred chronostratigraphically earlier in SE Turkey than in NW Europe and on the East Coast of the US.
Melissopalynology, the analysis of pollen grains present in honey, provides relevant information about the pollen and nectar sources in a region utilised by bees for the production of honey, which is used to determine the geographical and botanical origin of the honey. The present investigation is carried out on 20 winter honey samples collected from urban localities of Allahabad to identify the important source plants of the region. The methodology recommended by the International Commission of Bee Botany was followed. Analysis of 20 honey samples recorded a diversity of 62 pollen types, amongst which 49 pollen types were found to originate from entomophilous/amphiphilous taxa, and 13 from anemophilous taxa. Thirteen honey samples were found to be unifloral while the remaining seven samples were multifloral. Brassica campestris, Ageratum conyzoides, Bombax ceiba and Citrus sp. were the predominant pollen types. Fourteen pollen types were recorded in the secondary frequency class, while 27 and 50 pollen types were found in important minor and minor frequency classes, respectively. With regard to the frequency of occurrence of pollen types in honey samples, Brassica campestris, Ageratum conyzoides and Coriandrum sativum were found to be very frequent pollen types as they were recovered from more than 50% of the honey samples. Findings of the present melissopalynological study suggest Brassica campestris, Ageratum conyzoides, Bombax ceiba, Citrus sp. and Coriandrum sativum are the important source plants of Allahabad.
The pollen morphology of Mourera (Podostemaceae) was analysed with the aim of providing detailed descriptions of pollen for all species of the genus. Pollen grains were obtained from anthers of flower buds, acetolysed, and examined using light and scanning electron microscopy. The pollen grains are monads, small or medium sized, prolate in shape, with a circular or subcircular amb. Pollen grains are tricolpate, and the colpus was variously ornate and has distinctive ornamentation between apertural and non-apertural regions. The exine is thin and microechinate with supratectal spines in all species. In M. fluviatilis, M. monadelpha and M. schwackeana the surface has inconspicuous spines without delimited basis; in M. alcicornis, M. aspera, M. elegans and M. weddelliana, the surface has spines at the apices of ‘mamiloid elements', with a wide base of spines individualised and well defined. Hierarchical cluster analysis (HCA) was used to divide the main pollen taxa into three groups based on pollen morphology. Statistically distinctive taxa were identified using principal component analysis (PCA). Pollen analysis revealed a significant overall correspondence between pollen variations amongst species of Mourera and phylogenetic patterns.
Pollen morphology of 58 species and two subspecies of the genera Agrostemma, Cucubalus, Lychnis and Silene of Chinese Sileneae was studied using scanning electron microscopy. Among them, 50 species and one subspecies were reported for the first time. The results demonstrate that the number of pores and pollen surface ornamentation have important systematic significance. The surface ornamentation can be divided into four types, namely microechinate-perforate, microechinate-punctate, microechinatereticulate and microechinate-punctate-perforate. The palynological characteristics support that (i) Cucubalus and Lychnis should be classified into Silene; (ii) Agrostemma and Silene are sister groups; and (iii) the infrageneric classification of Silene still needs further study.
Simple apertures (3–4-colpate) are known to occur in the pollen grains of Capsella bursa-pastoris of the Brassicaceae. In this study we record the occurrence in this species of composite apertures (3-colporate) at higher frequency, for the first time, in addition to 3-colpate grains from Sikkim Himalaya.
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