Pollen morphology of 15 species of the genus Lactuca L. (s. lat.) of the tribe Cichorieae from the Hindukush, Western Himalayan and Karakorum Ranges was studied using light microscopy and scanning electron microscopy. The pollen morphology of six speciesm viz. L. erostrata Bano & Qaiser, L. glaucifolia Boiss., L. persica Boiss., L. crambifolia (Bunge) Boiss., L. chitralensis (Tuisl.) Ghafoor, Qaiser & Roohi Bano and L. picridiformis Boiss., was never studied before. Pollen were found to be isopolar, spheroidal to oblate-spheroidal, elliptic to rarely circular in equatorial view, hexagonal in polar view, trizonocolporate and echinolophate with 15 lacunae. Morphometric analysis of the pollen characters was conducted using agglomerative cluster analysis with Euclidean distance and Ward's method to compute the dissimilarity matrix, and a dendogram was prepared. Two pollen types, based primarily on the diameter of the polar and equatorial axes of the pollen grain, were recognized. Keys to the pollen types, subtypes and species are provided. The present palynological findings are to a great extent in agreement with the results of recent phylogenetic studies based on molecular evidence. Moreover, both the pollen types are well correlated with the general morphology of the investigated species of the genus Lactuca L. (s. lat) and provide additional micromorphological characters for the delimitation of the species.

The upper Palaeozoic basins of central-western Argentina include continuous fossiliferous successions spanning the Carboniferous-Permian interval. The palynostratigraphic biozones comprise Late Mississippian, Pennsylvanian and Cisuralian assemblages. Recently, new palynofloras of the La Veteada Formation were referred to the Lopingian (late Permian). However, they are characterized by spores and tetrads of Lundbladispora spp. and Densoisporites spp., pollen grains of Lunatisporites pellucidus, L. noviaulensis and Protohaploxypinus samoilovichii, and the alga Syndesmorion stellatum, that distinguish the post-Permian recovery floras worldwide. A new uranium-lead chemical abrasion-isotope dilution-thermal ionization mass spectrometry (U-Pb CA-ID-TIMS) age confirms the Olenekian age of this stratigraphic unit and allows the identification of the first Early Triassic palynofloras in this region of western Gondwana. Comparison and correlation with similar assemblages from the southern and northern hemispheres supports the Early Triassic turnover with an increase of lycopsid cavate spores associated with some diagnostic species of taeniate and non-taeniate bisaccate pollen.

This article is the first contribution to the characterization of monofloral honeys from the Dry and Humid Chaco that combines palynological and physicochemical parameters. The study focuses on the most represented honeys. Physicochemical parameters such as color, electrical conductivity, moisture, acidity and pH were analyzed for a total of 116 honeys classified as monofloral by pollen analysis. All the parameters considered were within the accepted range. Color and electrical conductivity were the most distinctive features, as stressed by multivariate (cluster analysis (CA) and principal component analysis (PCA)) and correlation analysis. The darkest honeys (i.e. black, dark amber and amber) were those from Tessaria integrifolia, Schinopsis balansae, S. lorentzii and Baccharis–Eupatorium-type pollen, and the lightest honeys (i.e. light amber and extra light amber) were those from Cynophalla retusa, Eugenia uniflora, Copernicia alba, Prosopis alba and Helianthus annuus. Mean values for electrical conductivity ranged from 0.4 to 0.8mS cm^–1, with the highest values detected in the darkest honeys, which are mainly produced in the Dry Chaco. The intense color of these honeys also suggests the presence of antioxidants. Thus, the color, electrical conductivity and antioxidant properties are important factors for future research to consider, to obtain a reliable authentication of the botanical and geographical features of these honeys.

Pollen and spores were recovered from the Paleocene Fort Union Formation and Paleocene–Eocene Willwood Formation of the Bighorn Basin (BHB), northwestern Wyoming, USA. In many local stratigraphic sections in the BHB, the base of the Eocene has been identified by the characteristic negative carbon isotope excursion (CIE) that marks the beginning of the Paleocene–Eocene Thermal Maximum (PETM). The palynotaxa from outcrop samples were examined using light microscopy (LM) and scanning electron microscopy (SEM). Seven new species are formally described (Tricolpites vegrandis, Rousea spatium, Striatricolporites astutus, Striatopollis calidarius, Friedrichipollis geminus, Retistephanocolporites modicrassus and Retistephanocolporites pergrandis). The temporal and geographic distributions of many of these palynotaxa suggest that hotter and more seasonally dry climates facilitated their northward range shifts during the PETM from the tropics or subtropics of the USA. For the temperate palynotaxa, the hotter and seasonally dry conditions resulted in local extirpation. A reevaluation of the palynostratigraphic schemes established for the Paleocene–Eocene boundary confirms that the first appearance of Platycarya platycaryoides denotes the Paleocene–Eocene boundary in the Rocky Mountains region. A new Striatopollis calidarius Subzone, associated with early Wasatchian (Wa) Wa-0 and Wa-R faunas, is also recognized for CIE body localities in the BHB.

Monogeneric clusters of five acritarch genera (Adara, Cymatiosphaera, Eliasum, Synsphaeridium and Timofeevia) were discovered in palynological residues obtained from fine-grained siliciclastic samples from the middle Cambrian (Miaolingian) Jince Formation of the Příbram–Jince Basin (Czech Republic). The clusters consist of two to more than 100 individual specimens and lack a common pattern of organisation. Acritarchs within clusters fall within a similar size range, regardless of generic affinity. Proposed mechanisms for the formation of these acritarch clusters are discussed: for the Jince Formation clusters, aggregation within algal blooms or primary colonial behaviour are the most plausible explanations. In addition, a summary of reports of acritarch clusters from lower Palaeozoic strata is included: clusters of a variety of acritarch genera have been documented from rocks of early Cambrian to Late Devonian age.

Middle Miocene (Serravallian; upper Badenian–lower Sarmatian) strata recovered in 10 cored boreholes (83 samples) from Bad Deutsch-Altenburg, Vienna Basin, Austria, were analysed palynologically for the first time. The strata belong to the Rabensburg Formation of the Baden Group. The lateral distribution of the boreholes in reference to a Mesozoic ridge makes this area interesting for studying various aspects such as distribution of deposits, stratigraphy and palaeoenvironmental reconstruction. A diverse and well-preserved in situ dinoflagellate cyst association has been identified. Middle Miocene age-diagnostic species including Cannosphaeropsis passio, Cerebrocysta poulsenii, Habibacysta tectata, Labyrinthodinium truncatum, Operculodinium? borgerholtense and Unipontidinium aquaeductum are recorded. Their occurrences allow correlation with dinoflagellate cyst biozonations on a regional scale. Based on the identified dinoflagellate cysts and by correlation with calcareous nannoplankton and ostracods, from the same set of samples, a Serravallian age – corresponding to a late Badenian and early Sarmatian age (regional Paratethys stages) – is confirmed. Reworked (Cretaceous and Paleogene) dinoflagellate cyst assemblages, also well preserved, were recorded abundantly from boreholes HA 521 and HA 573 (south-west of the Mesozoic ridge). In accordance with ostracods, the Badenian–Sarmatian boundary can be traced in the upper part of borehole HA 66 based on an abrupt change in the dinoflagellate cyst assemblages. The upper Badenian strata were deposited in a coastal to inner shelf environment with terrigenous (siliceous sand and clay) and carbonate sediments. The recorded dinoflagellate cysts reflect marine, tropical to warm-temperate climatic conditions. The composition of the recorded dinoflagellate cyst assemblages is very close to that of the Middle Miocene assemblages of the Mediterranean, indicating water exchanges between the Central Paratethys and the Mediterranean during the late Badenian (early Serravallian).

Campomanesia is a well-delimited Neotropical genus of Myrtaceae, but some of its species have a poorly understood circumscription. Pollen morphology can provide characters to clarify the relationships among such taxa. Here, we analyze the pollen grains of 16 species of Campomanesia using light and scanning electron microscopy. Heat map and multivariate regression tree analyses were performed aiming to detect differences among species based on pollen morphology. Pollen grains of the studied taxa are isopolar monads that are oblate or, less often, suboblate, 3(4)-colporate, syncolporate or parasyncolporate, with a triangular or quandrangular amb. The exine ornamentation varies among rugulate-granulate, granulate, rugulate and rugulate-espiculate. Fastigium is present in 14 species, and a costa is present in three species. The heat map and regression tree analyses based on 16 character states of pollen morphology were able to distinguish all species of Campomanesia studied here. Some species differ from all the other species, such as Campomanesia guaviroba due to its exclusively rugulate exine. Amb, shape and exine ornamentation were distinctive characters, as previously reported for other genera of Myrtaceae. However, the presence of fastigium also proved to be an informative pollen character for species distinction in Campomanesia. Based on the sample of this study, we can state that Campomanesia is a eurypalynous genus within Myrtaceae.

During the warm middle Eocene (ca 45 Ma), the Napartulik area (also called ‘the Geodetic Hills’), Axel Heiberg Island, northern Canada (Nunavut), was vegetated with mixed broad-leaved deciduous angiosperm and evergreen conifer forests over extensive floodplain and forested wetland habitats. Massive organic rich sedimentary successions and encapsulated in-situ tree trunks suggest these forests were drowned by frequent flooding events. The sedimentary layers contain sub-fossil amber that was produced by representatives of the Pinaceae such as Pseudolarix. The amber offered an opportunity to investigate aerial plankton and thus the chance to discover microfossils, which could provide evidence of biotic interactions associated with, or the cause of, the forest die-offs. Fifty-four amber samples were subjected to a solvent treatment for microfossil extraction followed by light microscopy, resulting in the discovery of several hundred microfossils. Unexpectedly, one-quarter of the microfossils were diatoms, which may predominantly have lived on the tree bark. Fungal spores were rare, and the pollen grains found corroborated earlier findings in litter or coal. The records of fungal spores and arthropod remains were insignificant and could, therefore, not substantially have been contributing to the forest die-offs. More resin analyses from the complete sedimentary profile would be needed to get a clearer picture of putative forest pests and prevailing environmental conditions

The ecosystem services offered by honey-producing bees are highly significant for the fertilization of flowers to produce fruits and seeds. The pollen found on bees and in honeycombs and honey represents the type of vegetation visited by the bees. The pollen diversity of honeycombs built by four honey-producing bees of the west coast and Western Ghats of India was evaluated to identify the floral sources. A spectrum of 54 pollen types (belonging to 52 genera in 34 families) was identified on the west coast, while 94 pollen types (belonging to 73 genera in 41 families) were identified in the Western Ghats. The results show that the bees of the four species on the west coast visited a limited number of plant species to gather nectar but included a higher quantity of total pollen of specific plant species. In the Western Ghats, the same species of bees visited more plant species but obtained lower quantities of pollen of specific plant species. This study shows that the honey-producing bees of the west coast and the Western Ghats prefer multifloral nectar for the production of honey. Floral resources for honey-producing bees are more diverse in the Western Ghats than on the west coast of India. Such differences might influence the quality (physical and nutraceutical) of honey produced by the bees in different geographic regions.

Pollen morphology of 12 species, representing genera of the tribes Brassiceae, Conringieae, Isatideae and Plagiolobeae were studied using light microscopy (LM) and scanning electron microscopy (SEM). The results demonstrated that the polar diameter, pollen exine ornamentation, mesocolpium width, and exine thickness have important systematic significance. Pollen grains in these genera were tricolpate and their shapes varied from prolate to perprolate, with the polar axis length ranging from 30.28 to 41.05 µm and the equatorial axis length ranging from 17.21 to 23.36 µm. However, fine details can be used to distinguish pollen grains of the different species within the genera. The exine ornamentation varied among genera within the tribes and among species within the same genus. Three pollen types are distinguished based on lumen size. All the studied tribes' pollen were heterogeneous, with reticulate, microreticulate (Conringia orientalis, Plagioloba derakii), or macroreticulate (Moricandia sinaica) ornamentation. The exine thickness ranged from 0.75 to 2.60 µm. Pollen characteristics support: (i) two distinct pollen types (viz. Conringia austriaca and Iljinskaea planisiliqua types) in all four tribes; (ii) the similarity of the pollen shape between tribes Isatideae and Brassiceae; (iii) the transfer of P. crenulata from Zuvanda to Plagioloba, and of I. planisiliqua from Conringia to Iljinskaea. Plagioloba clavata displays great variation in pollen morphological characters and needs to be further studied. A key to the species of the genera was also provided.

The Tacaná volcano in southern Mexico, is one of the most important areas for conservation in the Mesoamerican biodiversity hotspot. Yet, traditional floristic inventories in the area have been limited by access to remote zones along its 4000m elevation gradient. To achieve an accurate view of vegetation structure and spatial dynamics, we sampled moss pollsters from elevation locations along the entire Tacaná elevation gradient. We observed a strong correlation between pollen spectra and elevation variations, reflecting general vegetation patterns. Main vegetation types along the elevation gradient included tropical rain forest (from 500 to 1500 m), with relative high abundance of Moraceae, Ficus, Alchornea, Fabaceae and Bombacaceae. Montane rain forests were distributed from 2000 to 2500m, and pollen spectra were dominated by Alnus, Clethra, Cyathea, Quercus, Alchornea, Ilex and Bombacaceae. Temperate forests were located at elevations ranging from 2800 to 3000m, in association with Pinus-Alnus forests. Pinus forests were recorded at highest elevations from 3000 to 4000m. In addition, relative humidity was the main factor determining elevation distribution and vegetation change in the area. We argue that up-climbing warm winds favor the distribution of tropical taxa towards higher elevations, thus allowing landscape plant connectivity. Biogeographic and local/regional factors –likely volcanism activity- might govern temperature fluctuations and immediate and long-term effects of the climatic distribution on the associated flora and on biodiversity as a whole.

The floral resources used by Apis mellifera as pollen source include those present in natural forests like the Yungas as well as forested areas. The aim of this work was to determine the main pollen resources harvested by A. mellifera and their variation during the honey production season. Forty pollen load samples were randomly collected from apiaries located in four sites (Tilquiza, El Fuerte, Los Alisos and Los Toldos) in spring and summer between 2011 and 2017. Sampling was conducted using pollen traps and the samples were subjected to conventional melissopalynological techniques. Pollen sources were identified using palynological atlases and compared with the reference palynotheca. A total of 70 pollen types distributed in 39 botanical families were identified, with the following families having the highest index of family importance (IF): Asteraceae (23.9), Fabaceae (19), Myrtaceae (12.8), Poaceae (8.3), Euphorbiaceae (8.2) and Vitaceae (4.3). The main resources used were: Mimosa, Eupatorium, Blepharocalyx salicifolius, Baccharis and Sebastiania. A pollen diagram was used to analyze the different pollen resources used throughout the study seasons. Species foraged in spring included B. salicifolius, Anadenanthera colubrina, Parapiptadenia excelsa and Sebastiania and those foraged in summer included Mimosa, Viguiera, Type Cissus and species of the family Poaceae; all of these species are native to the forest. The present results contribute to the knowledge of polliniferous species of the Yungas and evidence the importance of this bee as flower visitor in the forest.

Monosulcate pollen grains are an important component of the Mesozoic palynofloras around the world. These type of grains are produced by several groups of plants and because of the morphological similarities among them, their taxonomic determination is difficult. Currently, there is scarce information about morphological differences of monosulcate pollen grains and this makes their botanical affinity in fossil specimens challenging. In this work, we analyzed statistically the morphological features of monosulcate fossil pollen grains recovered from six palynological assemblages from the Lower Cretaceous Lagarcito Formation of central-western Argentina. We used our own fossil dataset and data from the description of monosulcate pollen grains published from Cretaceous cycadalean in situ male cones from Patagonia. Furthermore, morphological variables from selected living species were added to support the analysis. According to our results, two main groups with clear morphological features were characterized among fossils. The use of an extant dataset allowed us to support the exine sculpture as an important variable when characterizing fossil pollen grains. Finally, our fossil dataset showed similarities with the in-situ pollen grains from the cycadalean cone species Androstrobus munku and Androstrobus patagonicus. This work is the first attempt to identify different morphological types among fossil monosulcate pollen grains recovered from the Lagarcito Formation of central-western Argentina. Our results will contribute to elucidate morphological variations in fossil pollen grains and may improve future taxonomic studies.