This is the first study of exine ultrastructure to be performed in five endemic Mexican Mimosa taxa (M. pringlei var. pringlei, M. calcicola, M. spirocarpa, M. caerulea and M. sousae), one occurring in Mexico and Central America (M. occidentalis), one widely distributed throughout the neotropics (M. setosa var. paludosa), and two in South America (M. irrigua and M. daleoides). Mimosa pollen grains are associated in polyads (12 grains), octads and tetrads. Polyads and octads in members of the basal clade of Mimosa phylogeny (sect. Mimadenia) evince the affinity of Mimosa with Piptadenia. Octads are retained in sect. Batocaulon and tetrads are evolved in this section. More recent clades (sect. Habbasia, Mimosa and Calothamnos) only show tetrads varying in size and shape. Polyads show greater variation in the exine layers, with a bistratified granular structure. Octads display a columellar-granular infratectal structure while tetrads in sect. Mimosa exhibit a less variable exine with a granular infratectal structure.

Modern pollen–vegetation studies are crucial for the calibration and interpretation of fossil pollen assemblages. In eastern India, knowledge regarding the relationship between pollen deposition and the modern-day vegetation is required to make use of fossil pollen data, which is still scant. To fill this gap, the present study deals with the pollen analysis of 20 surface sediment samples from the Sajnekhali Island Wildlife Sanctuary, Sundarbans, India. The palynological results show that 20 genera in 18 families are identified, of which 16 major pollen taxa are recorded under mangrove and its associate groups. To understand potential drivers changing pollen abundance in the surface samples, a detrended correspondence analysis (DCA) is conducted to typify the environmental gradients among samples. The DCA of the modern pollen assemblages reveals the taxa defining the environmental gradient from inland to the margin of the island. The primary gradient appears to be the salinity tolerance of mangroves from near the water margin to the less salt-tolerant taxa. Axis 1 describes 62.5% of the variance in the dataset. The secondary axis appears to describe the gradient in subtaxa away from the mangrove. Axis 2 describes 4.5% of the variance in the dataset. Rhizophora mucronata, Avicennia marina, Sonneratia apetala, Excoecaria agallocha, Heritiera fomes, Bruguiera gymnorrhiza, Xylocarpus granatum and Nypa fruticans are recorded as the dominant pollen taxa that follow a salinity gradient. All modern pollen rain appears compatible with the actual floristics of the area. Thus, the present study indicates that the mangrove environment is well represented in the pollen record and displays close linkages between pollen composition and native parent plants in the area. This pollen dataset fills an information gap and is useful in understanding and interpreting the palaeoecology and palaeoenvironment of tropical marshes of similar environments.

Palynological studies in central Amazonia are scarce, especially those concerned with resolving the age of sedimentary deposits. A recent opportunity allowed the stratigraphical and palynological study of a sedimentary unit below the Negro River's current channel. Age was constrained by the basal occurrence of Alnipollenites verus, and the top occurrence of Grimsdalea magnaclavata and Paleosantalaceaepites cingulatus, as late Pliocene to early Pleistocene. Here, we provide additional details on the palynostratigraphy and biodiversity of this deposit. Samples yielded 95 palynomorphs that included 58 pollen and 26 spore species, of which we identified botanical affinities with 26 angiosperm, one gymnosperm and four pteridophyte families. Twenty-five new taxa are erected, from which we recognise five angiosperm genera, namely Pacourina/Vernonia (Asteraceae), Myrsine? (Myrsinaceae), Symmeria (Polygonaceae), Faramea (Rubiaceae) and Schefflera (Araliaceae), plus a possible Marcgraviaceae pollen. These taxa, along with the majority of the recovered assemblage, are indicative of Amazonian lowland floras.

In this study, the pollen morphology of 22 Turkish taxa (12 of which are endemic) of the taxonomically complex genus Thlaspi L. sensu lato was studied with light microscopy (LM) and scanning electron microscopy (SEM). We found that the pollen of Thlaspi are usually bilateral symmetric and anisopolar. They are prolate, subprolate, perprolate or spheroidal, with the polar axis ranging from 14.13 to 28.36 µm and equatorial axis from 8.75 to 19.48 µm. Pollen are usually tricolpate, but some of them are 1–2- or 4-colpate. The ornamentation of pollen of the examined taxa is usually micro or macro reticulate, and rarely foveolate. The exine thickness ranges from 1.59 to 2.75 µm, and the intine thickness from 0.54 to 0.94 µm. As a result of this study, some of the pollen characters such as the sizes of pollen and colpus, ornamentation of exine, apocolpidium, and shape and diameter of amb are found to be significant morphological characters for taxonomic use.

Honey samples from stingless bees (tribe Meliponini) were analyzed in three Sataré Mawé indigenous communities located along the edges of the Maruá River in the state of Amazonas, Brazil. Twenty-nine pollen types were identified for the Scaptotrigona nigrohirta colonies from the Ilha Michilis community, 43 for the Scaptotrigona sp. colonies and 39 for the Melipona seminigra colonies from the Nova Esperança community, and 34 for the M. seminigra colonies from the Monte Horeb community. Regarding the presence or absence of different pollen types in the samples, from the 65 pollen types identified, five were exclusive for the Scaptotrigona sp. from Nova Esperança, five for M. seminigra from Monte Horeb, six for S. nigrohirta from Ilha Michilis, and 13 for M. seminigra from Nova Esperança. Of the main pollen types identified (n = 22), the Miconia type had the highest proportion and was the only type shared by the bees from the three communities. The present study provides a list of important plants to be included in bee pastures for the studied bees in the Amazon, with the aim of developing stingless beekeeping as a subsistence activity in indigenous communities.

The palynological investigation of 30 outcrop samples from seven sites in and near the Qattara Depression, north Western Desert, Egypt, has yielded six samples from three sites containing poorly to well-preserved assemblages including dinoflagellate cysts, freshwater algae, acritarchs, pollen and spores. The sites have not been dated previously, but dinoflagellate cyst evidence reveals an early or middle Rupelian (Early Oligocene) age for one sample (overlapping ranges of Tuberculodinium vancampoae and Phthanoperidinium comatum) and early Rupelian or older (occurrence of Lentinia serrata) for another, establishing time equivalence with the Upper Eocene–Oligocene Dabaa Formation. The palynological assemblages reflect fluctuating conditions on the southern margin of the Tethys/Paratethys Ocean, with the frequent co-occurrence of Homotryblium floripes, Pediastrum and Botryococcus reflecting restricted and probably lagoonal marine environments influenced by seasonal river inflow. Despite low global sea levels during the Early Oligocene, marine conditions evidently extended as far south as the southern Qattara Depression. Outcrops in the north Western Desert are typically deeply weathered and barren of palynomorphs, this being the first report of dinoflagellate cysts from surface sections of the Qattara Depression and its surroundings.

The morphological diversity of pollen brings important information on the taxonomy of plants present in past and current ecosystems. Regarding the rich biodiversity and the large number of endemic plant species on the island of Madagascar, pollen reference collections are still scarce for this part of the world. The main objective of this study was to conduct a preliminary investigation of pollen morphology of flowering plants visited by honeybees in a tropical rainforest of the south-east part of Madagascar during 2014 to 2015 (Ranomafana National Park – Fianarantsoa). Samples of 135 species belonging to 105 genera and 52 families were processed, employing the standard acetolysis method. Pollen reference slides of these melliferous plants were mounted. These pollen grains were then photographed and measured using light microscopy. The 135 collected species include 54 trees, 47 shrubs, 21 herbs, 12 lianas and one epiphyte, among which 85 taxa are endemic, 46 indigenous and four exotic. Pollen morphological characteristics of 106 species (85% endemic) are described here for the first time. Since these endemic plant taxa have co-evolved with the endemic honeybee of Madagascar, Apis mellifera unicolor, the implications of the pollen grain morphology for plant–pollinator co-evolution are discussed.

The scolecodonts (polychaete jaws) are a significant group of dispersed palynomorphs in Palaeozoic rocks. The growing literature considering the taxonomy of fossil jaw-bearing polychaetes presents some debates on their systematics and has generally limited their role in biostratigraphy. This contribution is the first record that focuses on the scolecodonts from the Devonian (Eifelian) subsurface succession in the Western Desert of Egypt and their biostratigraphic significance. The jaw apparatuses of four different polychaete families are examined and documented from the Devonian of Faghour-1X borehole. The identified families are Paulinitidae, Kielanoprionidae, Polychaetaspidae and Mochtyellidae. Four genera are identified: Kettnerites, Oblongiprion, Oenonites and Mochtyella. The scolecodont associations are compared with coeval associations of the same age from other Gondwanan, Baltic and Laurentian areas to assess their palaeogeographic distribution and biostratigraphic importance.

Bignoniaceae Juss. are widely distributed in tropical and subtropical regions. Most of their Neotropical species have a climbing habit, which makes the family one of the most ecologically important in the Americas. This study of pollen morphology from 23 Bignoniaceae species in Brazilian forest fragments aimed to investigate new pollen characteristics of the family by light and scanning electron microscopy, which can assist in delimitating Bignoniaceae species and taxonomy. Another aim of the study was to analyze the evolution of the family's pollen characteristics. The pollen grains were acetolyzed, measured and photographed. We describe the pollen grains based on qualitative data, and quantitative data were analyzed using descriptive and multivariate statistics. Based on the qualitative data, an ancestral reconstruction of pollen morphology characteristics was performed for the taxa analyzed. We used the pollen data to understand the relationships established by previous phylogenies. The pollen grains are monads or tetrads, apolar or isopolar, and medium to large, with circular, subcircular to subtriangular amb; oblate to oblate-spheroidal; inaperturate, 6-colpate, (7)-8-(9)-colpate or 3-colporate with short or long colpi that are narrow, wide or very wide and with or without margo; lalongate endoapertures sometimes not evident; and psilate perforate, microreticulate or reticulate exine, homoor heterobrochate, with simpli or duplicolumellate muri. This result confirms Bignoniaceae as a eurypalynous family, and it allows the identification of pollen morphological characteristics shared by genera and species studied.