Palynology

Alternanthera (Amaranthaceae) is a diverse genus largely restricted to the American Tropics that belongs to the alternantheroid
clade containing C4 and C3–C4 intermediate species. This research focuses on the study of pollen characters by studying
13 species, representatives of the two major clades and subclades of Alternanthera. General palynological comparisons were
conducted with light microscopy (LM), scanning electron microscopy (SEM) and with confocal laser scanning microscopy
(CLSM) for exine ultrastructure. Twenty-five characters were measured and described for Alternanthera and among these,
14 pollen characters were used to discriminate pollen groups using cluster analysis and canonical analysis of principal
coordinates (CAP). Pollen form and ornamentation, pores number, spines length, number of ektexinous bodies and
nanospines on the ektexinous bodies on pore membranes, arrangement of nanopores and spines on structural elements,
and metareticula form were taxonomically important and therefore used to construct the first palynological key to the
alternantheroid clade species. Our study indicates that the seemingly subtle morphological variation of pollen is useful for
recognising three main pollen types within Alternanthera. The much needed palynological terminology for describing the
mesoporium in the metareticulate pollen of Amaranthaceae is provided.

Pollen analysis of six honey samples of Apis dorsata collected from Varanasi district has been carried out. Altogether, 37 pollen types were identified. Two honey samples were unifloral and four were multifloral in nature. Brassica campestris and Ageratum conyzoides were the predominant pollen types in unifloral honeys. In multifloral honey Brassica campestris, Ageratum conyzoides, Callistemon citrinus, Parthenium hysterophorus, Holoptelea integrifolia and Lathyrus aphaca were the secondary pollen types. In total honey samples Brassica campestris, Ageratum conyzoides, Callistemon citrinus, Coriandrum sativum, Eucalyptus globulus, Carica papaya, Citrus sp., Crotalaria juncea and Poaceae were very frequent in occurrence. Majority of pollen grains recovered from honey samples belonged to entomophilous taxa (54.05%) and amphiphilous taxa (32.48%) while 13.15% pollen were from anemophilous taxa. Present study suggests that Brassica campestris, Ageratum conyzoides, Callistemon citrinus and Coriandrum sativum can be regarded as the major bee source plants of the region.

Present day vegetation patterns in Northwestern Europe are the result of the interaction between the abiotic landscape , human interference, climate and vegetation. Often, palaeovegetation reconstructions are only based on pa-lynological data. When reconstructing past vegetation patterns, the abiotic landscape and archeological data can provide additional and very useful information. Especially, in geomorphological dynamic and heterogeneous areas these data can be used to reconstruct vegetation patterns in between palynological data points. In the Netherlands numerous detailed palaeogeographical maps and a rich archaeological record are available. To use these data for a regional vegetation reconstruction a new interpretative method was developed which reconstructs the distribution of past vegetation communities on the basis of the reconstructed geomorphology. The method is applicable in all regions where there is sufficient information about the abiotic landscape and its development, archaeology and a good coverage of palynological data. The method was applied in a heterogenous Weichselian coversand region, Twente, in the eastern part of the Netherlands and in the dynamic Holocene Rhine-Meuse delta in the central part of the Netherlands. The method is both applicable to visualize long-term vegetation dynamics as short term shifts.

Although Cretaceous fossils (coal excluded) from Victoria, Australia, were first reported in the 1850s, it was not until the 1950s that detailed studies of these fossils were undertaken. Numerous fossil localities have been identified in Victoria since the 1960s, including the Koonwarra Fossil Bed (Strzelecki Group) near Leongatha, the Dinosaur Cove and Eric the Red West sites (Otway Group) at Cape Otway, and the Flat Rocks site
(Strzelecki Group) near Cape Paterson. Systematic exploration over the past five decades has resulted in the collection of thousands of fossils representing various plants, invertebrates and vertebrates. Some of the best-preserved and most diverse Hauterivian–Barremian floral assemblages in Australia derive from outcrops of the lower Strzelecki Group in the Gippsland Basin. The slightly younger Koonwarra Fossil Bed (Aptian) is a Konservat-Lagerstätte that also preserves abundant plants, including one of the oldest known flowers. In addition, insects, crustaceans (including the only syncaridans known from Australia between the Triassic and the present), arachnids (including Australia’s only known opilione), the stratigraphically youngest xiphosurans from Australia, bryozoans, unionoid molluscs and a rich assemblage of actinopterygian fish are known from the Koonwarra Fossil Bed. The oldest known—and only Mesozoic—fossil feathers from the Australian continent constitute the only evidence for tetrapods at Koonwarra. By contrast, the Barremian–Aptian-aged deposits at the Flat Rocks site, and the Aptian–Albian-aged strata at the Dinosaur Cove and Eric the Red West sites, are all dominated by tetrapod fossils, with actinopterygians and dipnoans relatively rare. Small ornithopod (=basal neornithischian) dinosaurs are numerically common, known from four partial skeletons and a multitude of isolated bones. Aquatic meiolaniform turtles constitute another prominent faunal element, represented by numerous isolated bones and articulated carapaces and plastrons. More
than 50 specimens—mostly lower jaws—evince a high diversity of mammals, including monotremes, a multituberculate and several enigmatic ausktribosphenids. Relatively minor components of these fossil assemblages are diverse theropods (including birds), rare ankylosaurs and ceratopsians, pterosaurs, non-marine plesiosaurs and a lepidosaur. In the older strata of the upper Strzelecki Group, temnospondyl amphibians—the youngest known worldwide—are a conspicuous component of the fauna, whereas crocodylomorphs appear to be present only in up-sequence deposits of the Otway Group. Invertebrates are uncommon, although decapod crustaceans and unionoid bivalves have been described. Collectively, the Early Cretaceous biota of Victoria provides insights into a unique Mesozoic high-latitude palaeoenvironment and elucidates both palaeoclimatic and palaeobiogeographic changes throughout more than 25 million years of geological time.