The botanical origin and seasonal variation of pollen collected by Tetragonisca weyrauchi were studied by means of palynology (pollen identification). The study was carried out between August 2016 and July 2017 with a hive introduced in a house garden in an urban area (09° 56′ 38.7″ S; 67° 52′ 42.9″ W) near the campus of the Federal University of Acre (UFAC). In total, we identified 87 pollen types from 31 botanical families, with the most representative ones being: Alismataceae, Amaranthaceae, Arecaceae, Boraginaceae, Cyperaceae, Euphorbiaceae, Fabaceae and Urticaceae, all displaying percentages above 10%. The pollen types Alternanthera (Amaranthaceae), Cecropia (Urticaceae) and Cordia sellowiana (Boraginaceae) obtained relative abundances above 90% and are therefore considered events of temporary specialization. The lowest diversity and evenness values were found for July (H′ = 0.127; J′ = 0.071) and August (H′ = 0.070; J′ = 0.043), and the highest values for October (H′ = 2.025; J′ = 0.715) and April (H′ = 1.941; J′ = 0.611), thus not suggesting relationships with the rainy (November–April) or dry (May–October) periods. Furthermore, there was no preference by the bees for morphological characteristics of the pollen such as size, exine texture or aperture number. However, the most representative grains are among the small and medium size, reinforcing the hypothesis that this bee species prefers small flowers available in dense inflorescences.

The genus Castanea, divided into seven extant species of trees worldwide, includes the American chestnut, C. dentata. This once common North American tree has been nearly eliminated from the landscape due to the appearance of chestnut blight early in the Twentieth Century. Castanea has a long history as a component of palynological assemblages, though megafossil paleobotanical remains are quite rare. The distributions of what are believed to be Castanea pollen as they have been derived from coastal plain and near-shore sediments dating back to the Neogene of the coastal plain of the southeastern US are discussed. The abundances of Castanea pollen in microfossil preparations are carefully considered relative to the concept of ‘pollen sum’ and while it appears that the trees were quite abundant as components of coastal woodlands during the Neogene, the actual number of pollen we found in samples is quite low. American chestnut trees continued to be important into the late Pleistocene and through the time when humans first occupied both coastal and inland areas of the southeastern US.

Apiculture is an important economic activity in Mexico, and deforestation, extensive agriculture, and other types of land use threaten sustainable honey production. This study aimed to determine the floral resources used by Apis mellifera for honey production, in vegetation types with different disturbance degrees in Southern Yucatan Peninsula, Quintana Roo state. A total of 24 honey samples, from eight apiaries, were collected during the months of the highest honey production in the region (February to May 2022). Standard acetolysis technique was applied for melissopalynological analysis. A total of 68 pollen types were identified. Our results suggest that the disturbance degree of the vegetation does not affect the pollen diversity and honey composition, mainly because the available floral resources remain similar. Viguiera dentata (Asteraceae) was the most abundant (>45%) herbaceous species in honey samples of February and March. Piscidia piscipula (Fabaceae) and Haematoxylum campechianum (Fabaceae) in samples of March (16%-45%), and P. piscipula in April (>45%). Spondias mombin (Anacardiaceae), Bursera simaruba (Burseraceae), and Metopium brownie (Anacardiaceae) were the most abundant (16%-45%) arboreal species found in samples of May. Although our results can be used to develop conservation strategies looking for sustainable honey production, further studies should focus on vegetation with a better conservation state, during longer time periods, and during periods with fewer resources available for honeybees.

Due to extensive introduction and breeding, the taxonomic relationships of Lonicera L. are unclear. Alternative scientific methods are needed to explore the classification of these new Lonicera. In this paper, the pollen morphology characteristics, karyotype features, and floral and fruit pigment components of 13 taxa of Lonicera were analyzed by means of scanning electron microscopy, karyotype analysis, High Performance Liquid Chromatography Mass Spectrometry (HPLC-MS) and Gas Chromatography-Mass Spectrometry (GC-MS). The 13 representatives of Lonicera were divided into groups of four, three, three and three taxa through the analysis of pollen morphology characteristics, karyotype features, floral composition and fruit pigment composition, respectively. Lonicera ruprechtiana and Lonicera tatarica always clustered together. Five hybrids, including Lonicera korolkow × Lonicera maackii and Lonicera korolkow × Lonicera tatarica No. 8 can generally be clustered with their parents. These results indicate that the analysis of pollen morphology characteristics, karyotype features, and floral and fruit pigment composition has value and significance for the study of systematic classification and relationships, and the conclusions of this study partially support morphological taxonomy.

The morphological characteristics of pollen grains of Linum species in Mexico have not previously been evaluated in quantitative terms. This study reports statistical values of pollen characteristics – polar axis, equatorial axis, shape, polar area, exine thickness, sexine thickness, nexine thickness, and height and diameter of ornamental pollen elements – of 11 of the 13 endemic species accepted to date and for which material was available: L. cruciata, L. flagellare, L. lasiocarpum, L. longipes, L. mexicanum, L. modestum, L. orizabae, L. pringlei, L. rzedowskii, L. scabrellum, and L. tenellum. The detailed light and scanning electron microscopy study revealed that the pollen is prolate-spheroidal to subprolate, tricolpate and with semitectate exine sculptured with bacula, clavae, gemmae or spines whose height and diameter follow a homogeneous, intermediate, or heterogeneous pattern. The principal component analysis found that five characters, namely the height of the ornamental elements, sexine thickness, exine thickness, diameter of ornamental elements, and nexine thickness, explained the highest percentage of the variance between species. The cluster and discriminant analyses classified some of the species into three groups and differentiated three of them according to their morphology. The difficulty in distinguishing some species through a conventional approach was solved conveniently using palynological traits since the ornamentation pattern of pollen grains was unique and because grains of various species were statistically different, thus representing a tool for identifying Linum species.

The main purpose of this study is the palynological characterization of Doronicum L. taxa that occur naturally in Turkey. In this context, the pollen morphology of 11 species and one subspecies of Doronicum was researched in detail by light microscopy and scanning electron microscopy (SEM). Furthermore, principal component analysis (PCA) and hierarchical cluster analysis (HCA) were carried out to identify closely related species and palynological characters that could potentially be used to distinguish the studied taxa. Pollen grains were found to be isopolar monad and tricolporate. Pollen were prolate-spheroidal in shape, with a circular amb. SEM showed the exine ornamentation was echinate-perforate. Differences in the bases and ends of the spines were observed; therefore, pollen grains were categorized based on spine morphology. Three components of the studied palynological characteristics were determined with PCA. The PCA results explained 78.79% of the variation, and polar diameter, equatorial diameter, diameter in polar view, exine thickness, intine thickness, pore length, colpus width, and spine length were found to be the most valuable palynological characteristics for discrimination of the Doronicum taxa. The HCA dendrogram also revealed three main clusters. This study is helpful for understanding the relationships among the taxa of Doronicum and provides insight for future taxonomic research.

Based on molecular phylogenetic and morphological studies, the new genera Sedobassia Freitag & G. Kadereit and Spirobassia Freitag & G. Kadereit were described in the tribe Camphorosmeae (Chenopodiaceae/Amaranthaceae sensu APG IV). Palynomorphological peculiarities are often used in taxonomy as additional diagnostic features. Pollen grains from 26 herbarium specimens belonging to 13 taxa of Bassia, Sedobassia, Spirobassia and Neokochia genera in Eurasia and North America were acetolyzed and studied using both light microscopy and scanning electron microscopy. Dry pollen grains were also studied. The structure of the columellae of pollen grains was analyzed for the first time in the current study. The aim of this research was to provide data on their pollen characteristics and to evaluate the taxonomic value of these data for generic and species-specific identification. The pollen grains are pantoporate, spheroidal in shape, circular in outline, slightly undulate, undulate or straight on the edges; and medium- or small-sized. Pores are circular, with distinct or indistinct margins. Exine sculpture is nanoechinate; tectum psilate or psilate-perforate. Pore membranes with nanoechini. Taxonomic relevance of the most important characters of pollen grains is discussed (pollen diameter, pore number, pore diameter, distance between pores and between pore centers, pollen diameter(C)/distance between pore centers(D) value, nanoechini density, presence/absence of perforations, structure of columellae, number of nanoechini on pore membranes). Pollen morphology proved to be an important additional source of information for species-specific identification. This study provides new data and analyzes the morphological features of pollen grains of Bassia (in the currently accepted circumscription), palynomorphological similarities, and differences between taxa of the genera Bassia, Sedobassia, Spirobassia, and Neokochia.

The Upper Triassic–Lower Jurassic succession in the Danish Basin is penetrated by many deep wells that were drilled during former hydrocarbon exploration campaigns, but it is today targeted for geothermal energy and storage of CO₂. The Stenlille salt dome on Sjælland sandstones of the Gassum Formation, sealed by the overlying Fjerritslev Formation mudstones, has been used for decades as a seasonal storage for natural gas. With its comprehensive dataset of seismics, geophysical well logs and conventional core data from 20 wells, the Stenlille succession serves as a model for other salt domes currently being evaluated as potential CO₂ storage sites in the basin. Over the last decade the cored Triassic–Jurassic boundary succession has contributed to the understanding of environmental and palynological events during the end-Triassic mass extinction. Core, sidewall core and cutting samples from several of the closely situated Stenlille wells are here used to establish a high-resolution palynostratigraphic zonation scheme covering the entire Rhaetian to Sinemurian succession by integrating new analyses with previously published data. The palynological dataset has allowed the recognition of nine formally described spore-pollen zones, of which eight are new, while two previously described dinoflagellate cyst zones are subdivided into three informal subzones each. The palynological zonation is integrated with a sequence stratigraphic framework and will form the basis for the dating of future well sections in the Danish Basin and other basins and for correlation to outcrops. The large palynological dataset further shows that the vegetation around the Danish Basin was remarkably stable during the early to middle Rhaetian, but that events related to the emplacement of the Central Atlantic Magmatic Province accelerated ecosystem changes for c. 175 ky in the late Rhaetian and earliest Hettangian, including ∼25 ky of successional recovery before the terrestrial ecosystem had again stabilised.

Calea comprises 157 species that occur in the Neotropics. The genus is organized into eight subgenera and 18 sections. Calea sect. Meyeria consists of eight species occurring exclusively in south-central Brazil. In this study, pollen grains from these eight species were sampled from herborized flower buds in pre-anthesis. Pollen samples were acetolyzed, measured, and photographed under a light microscope. Unacetolyzed pollen grains were examined under a scanning electron microscope. The results were used to characterize pollen morphology and construct a palynotaxonomic key for Calea sect. Meyeria. The analyzed pollen grains were monads, isopolar, usually medium-sized, oblate spheroidal, tricolporate, with lalongate endoaperture, the sexine echinate and thicker than the nexine, and six spines in the apocolpium region. The eight species have very similar pollen grains, but some characters are informative for this section, namely pollen size, polar area, sexine ornamentation, and endoaperture characteristics. Despite the similarity of the pollen grains, palynological analysis was able to contribute to the delimitation of Calea species, providing new information for species distinction within Calea sect. Meyeria.

Rutaceae (Sapindales) is represented by approximately 2040 species and 150–170 genera. Conchocarpus is the genus with the highest number of species and is circumscribed by a combination of character states, making it a polymorphic group. A recent study proposed a new genus, Dryades, formed by species formerly positioned in Conchocarpus. This study aims to describe the pollen morphology of Dryades species, comparing it with the palynology of phylogenetically related species, to present data that can characterize the species of Dryades. We analyzed the pollen grains of Dryades species and eight species of the genera Andreadoxa, Angostura, Erythrochiton, Galipea, Rauia and Conchocarpus. The pollen grains were acetolyzed, measured, described qualitatively, and analyzed quantitatively. Illustrations using light microscopy (LM) and scanning electron microscopy (SEM) are presented. Multivariate analysis was performed. The pollen grains are monads, isopolar, medium to very large in size, with subcircular to subtriangular amb, and oblate-spheroidal to prolate shape. The apertures are 3- or 5-colporate, varying in size (very small to very large colpi). The endoapertures are usually lalongate, rarely circular. The pollen grains analyzed are microreticulate, reticulate, macroreticulate, reticulate-baculate, baculate or verrucate-baculate. Both qualitative and quantitative characteristics of pollen grains proved to be important in distinguishing genera and grouping species within genera (in particular, the number of apertures, the length of the ectoaperture, the exine ornamentation and the size of the pollen grains). Dryades species show similarities in pollen morphology to species of related genera such as Andreodoxa, Galipea and especially Rauia. The shape of pollen grains and the number of apertures in Dryades are distinct from those found in Conchocarpus macrophyllus. The pollen data observed in this study confirm the pollen diversity of Rutaceae.

The early Cambrian Buen Formation (North Greenland) hosts an exceptionally rich fossil biota that has contributed significantly to our knowledge of early metazoans, yet the fossil remains of primary producers from this deposit have received less attention. Here we examine the palynological component of the Buen Formation, with a focus on acritarchs and filamentous microfossils. Our analysis revealed the presence of 49 form taxa, 15 of which are described for the first time in the Buen Formation. These include large elements of presumably benthic origin, together with cyst-like acritarchs. Comasphaeridium longispinosum Vidal 1993 is renamed Comasphaeridium? brillesensis nom. nov., and Comasphaeridium densispinosum Vidal 1993 is reassigned to a new genus, Pearisphaeridium, becoming Pearisphaeridium densispinosum comb. nov. The diagnoses of Pearisphaeridium densispinosum (Vidal 1993) comb. nov. and Skiagia pura Moczydłowska 1988 are emended. Further, careful analysis of disparity in the recovered assemblage has revealed the presence of numerous transitional morphologies among the recorded acritarch form taxa. Though some of these transitional forms likely represent biologically meaningful entities (e.g. life cycle stages, ecophenotypes), others appear to have been artificially generated by taphonomic processes. Accounting for taphonomic factors and other sources of morphological variation has curtailed diversity down to 30 acritarch morphotypes, ten of which represent distinct abundance peaks broadly corresponding to acritarch genera. This analysis illustrates how population-based studies of early Cambrian acritarchs can help to discern the different factors that impinge on acritarch morphology, detect instances of taxonomic inflation, and refine our measures of diversity at the base of early Palaeozoic food webs.

Cymatiosphaera hymenosynypha Morbey 1975, previously recorded from the Rhaetian Westbury Formation in the United Kingdom, occurs in Triassic–Jurassic boundary strata from Denmark. From the present study it is clear that this small, finely reticulate, ellipsoidal, two-layered palynomorph is not a prasinophyte, but a dinoflagellate cyst with a combination apical/intercalary archaeopyle (type tAtI) which involves three apical plates plus one intercalary plate. This cavate cyst is morphologically similar but not identical to Valvaeodinium hanneae Piasecki 2001 from the uppermost Bathonian to lower Callovian of East Greenland, and it is therefore here transferred to Valvaeodinium, as Valvaeodinium hymenosynypha (Morbey) Lindström comb. nov. The appearance of Valvaeodinium hymenosynypha in Rhaetian strata in the Danish Basin suggests that the lineage of cavate Valvaeodinium cysts originated in the Late Triassic alongside a chorate species of the genus. Valvaeodinium hymenosynypha seems to have survived just barely past the end-Triassic mass extinction as it is also present in the earliest Hettangian.