Eighteen native taxa and two introduced species of Thunbergia (Acanthaceae), representative for Southeast Asia, were characterized using pollen morphology. Light microscopy (LM) and scanning electron microscopy (SEM) were used to describe micromorphological pollen characters for species differentiation and then used in combination using principal coordinate analysis (PCoA) for classification and inferring evolutionary relationships. A key to species based on pollen morphology was constructed. Pollen is apolar and isopolar, monads and spheroidal or rarely convex triangular (T. colpifera) in shape. Apertures are syncolpate (spirapaturate), or rarely pericolpate (T. amphaii), or tricolpate (T. colpifera). Exine ornamentation is granulate, fossulate, fossulate with granulate, fossulate with micro-echinate, rugulate, micro-rugulate, clavate-like with fossulate or clavate-like with rugulate. Micro-rugulate ornamentation (T. coccinea) is described here for the first time in Thunbergia from Southeast Asia. We demonstrate that pollen morphology is useful for species identification and assessing the complex relationships of taxa in the T. fragrans complex group using multivariate analyses. According to pollen morphology, flower form and pollinators, we infer that T. colpifera is more primitive than the woody climber group (T. coccinea, T. grandiflora, T. hossei, T. laurifolia, T. lutea and T. papilionacea) and that the T. fragrans complex group is more derived within the genus.
The Gorgo a Cerbara section, located in the Umbria-Marche Apennines (Italy), represents a key stratigraphic reference section for the Lower Cretaceous (Barremian-Aptian transition) within the Tethyan domain. This 33.06 m thick succession spans the upper Maiolica and lower Marne a Fucoidi formations and includes the Selli Level, the sedimentary expression of the early Aptian Oceanic Anoxic Event 1a (OAE1a). A 6 m thick interval comprising the uppermost Maiolica and lowermost Marne a Fucoidi formations, including the Selli Level, was analyzed for its palynological content. The recovered assemblages are dominated by terrestrial miospores with subordinate marine elements (dinoflagellate cysts and acritarchs). The upper Maiolica Formation yielded abundant Druggidium deflandrei, Cassiculosphaeridia reticulata, and Pterodinium spp., alongside the first occurrence of Odontochitina operculata and the acritarch Pinocchiodinium erbae. The angiosperm pollen Afropollis cf. jardinus was identified below and within the Selli Level, indicating its earliest Aptian distribution. Palynological recovery sharply decreases in the overlying Marne a Fucoidi Formation, with sparse, poorly preserved dinoflagellate cysts and spores. Comparison with coeval Tethyan sections (Angles, La B & eacute;doule, Cismon, R & iacute;o Argos) reveals close similarity in palynological composition and key biostratigraphic events. The last occurrence of D. deflandrei near the top of magnetochron M0r and the first occurrence of O. operculata define the Barremian-Aptian boundary interval. The appearance of Afropollis cf. jardinus in the uppermost Maiolica Formation marks one of the earliest records of angiosperms in the Tethyan realm. Overall, the integrated palynological data refine the biostratigraphic framework of the Gorgo a Cerbara section, improving its chronostratigraphic calibration and reinforcing its status as a regional reference for the late Barremian-early Aptian transition across the Umbria-Marche Basin.
This study presents the first detailed palynological characterization of Hesperis sivasica, a recently described species from T & uuml;rkiye. To place the new species within its taxonomic context, pollen features were also analyzed for three closely related taxa: H. bottae, H. kotschyi, and H. thyrsoidea. These comparative species were selected based on morphological similarities and phylogenetic proximity indicated by previous ITS sequence analyses, with H. kotschyi representing the morphologically closest species and H. thyrsoidea and H. bottae representing its closest phylogenetic relatives. Both qualitative and quantitative pollen characters were examined using light microscopy (LM) and scanning electron microscopy (SEM). Multivariate cluster analysis was performed to assess the taxonomic closeness of H. sivasica relative to the other species. The results indicate that while all taxa share common Brassicaceae pollen features; tricolpate apertures and reticulate ornamentation, subtle differences in pollen shape, lumen size, and exine microstructure allow differentiation among them. H. sivasica is most closely related to H. kotschyi, followed by H. bottae and H. thyrsoidea shows the greatest divergence, reflecting both morphological and phylogenetic patterns. This study underscores the importance of integrated LM and SEM palynological analyses in resolving fine-scale taxonomic relationships and supporting systematic placement of new species.
This study provides the first comprehensive comparative palynological assessment of Turkish Clinopodium taxa. Despite the recognized diagnostic value of palynological traits in Lamiaceae, their contribution to infrageneric classification in Clinopodium has not been comprehensively evaluated for the Turkish taxa. Three taxa treated in Davis's Flora of Turkey - (Clinopodium umbrosum (M.Bieb.) K.Koch., C. vulgare subsp. arundanum (Boiss.) Nyman, and C. vulgare subsp. vulgare L.) - were comparatively analyzed with the recently described Turkish endemic C. hakkaricum Dirmenci and F & imath;rat. Both qualitative (pollen shape, exine ornamentation, aperture type, and lumen morphology) and quantitative (polar and equatorial axes, colpus length and width, exine and intine thickness) pollen parameters were evaluated by light and scanning electron microscopy. All examined taxa possess hexacolpate apertures, although considerable variability in pollen shape was observed (oblate, oblate-spheroidal, perprolate, prolate, prolate-spheroidal, subprolate). Lumen morphology was generally irregular. Based on quantitative data, C. hakkaricum typically exhibited the maximum quantitative values (polar axis: 41.24 +/- 4.18 & micro;m; equatorial axis: 44.17 +/- 5.31 & micro;m; intine thickness: 0.62 +/- 0.19 & micro;m; colpus length: 29.47 +/- 3.99 & micro;m; colpus latitude: 0.85 +/- 0.53 & micro;m), whereas C. vulgare subsp. arundanum displayed the minimum values (polar axis: 26.53 +/- 6.09 & micro;m; equatorial axis: 20.66 +/- 2.90 & micro;m; colpus length: 19.26 +/- 8.06 & micro;m). The cluster analysis based on principal component analysis (PCA) revealed a clear separation of the studied Clinopodium taxa into two major groups, indicating substantial morphological divergence among them. The clustering pattern also suggests that C. umbrosum and C. vulgare subsp. vulgare are more closely related to each other than to the other taxa, while C. vulgare subsp. arundanum represents the most divergent taxon. Among the analyzed traits, quantitative parameters (particularly polar and equatorial axis lengths and colpus metrics) accounted for the highest proportion of variance in the PCA and displayed the strongest discriminatory power.
The pollen morphology of 17 taxa belonging to the genus Atriplex L. was investigated using light and scanning electron microscopy in order to document palynological characters, assess their taxonomic utility, and contribute to the delimitation of taxa within the genus in T & uuml;rkiye. Pollen grains of Atriplex taxa are radially symmetrical, isopolar, pantopolyporate and spheroidal. Ornamentation is scabrate with conical tectal spinules. Pores are circular in shape, semi-sunken in structure. In some species of the genus Atriplex, polyploidy and hybridization contribute to heteromorphic pollen morphological features. Cluster analysis largely overlapped with the sectional grouping of the Atriplex taxa studied, and principal component analysis (PCA) identified the following key characteristics as the most valuable variables for separating the examined taxa: spinule length, spinule width, pollen diameter, pore number, and operculum number.
Local pollen represents a crucial paleoecological approach for monitoring the historical legacy of eastern Mexico's tropical montane cloud forests (TMCF), which are often shrouded in cloud or mist, although few studies have explored this area. This paper presents a taxonomic selection of local indicators from 48 sites across 12 altitudinal gradients in three forest patches subjected to varying tree cover loss, collected from moss polsters. Using Principal Component Analysis, we identified three zones based on their levels of disturbance, with the goal of determining traits of pollen grains and floral phenology that influence habitat differentiation. Then, we identified four potential categories to evaluate historical legacies (anthropogenic pressures): (a) habitat-specialist tree taxa, (b) specialized entomophilous taxa, (c) anemophilous pollen with a short dispersal range, and (d) disturbance taxa. Our results suggest that genera such as Bejaria, Clethra, Fagus, Juniperus, Magnolia, Zanthoxylum, Zea mays, and five plant families are significant for these paleoenvironments. Following the literature, we discuss the implications of our pollen indicators in evaluating different ecological thresholds, such as ecological resilience and the loss of functional diversity. For these purposes, some traits and attributes of pollen systematics and floral phenology are crucial to long-term habitat persistence. We conclude that our local indicators for persistent montane forests can be added to other studies concerning the ecological continuity of the TMCF.
Fossil fruits, seeds and wood are documented from the Nut Beds of the middle Eocene Clarno Formation (central Oregon, USA) but little is known about the palynoflora. Here, we perform a pollen survey of three sites (Red Gap, White Cliffs Jr. and Nut Beds) using light microscopy. We used scanning electron microscopy to obtain better taxonomic resolution for pollen grains from each site and performed a probability-based Bioclimatic Analysis to obtain paleoclimate estimates. Overall, we identified 1 lycopod, 5 fern, 4 conifer, 1 cycad, 1 Ephedra, 65 angiosperms, 54 pollen or spores of unknown affinity, 2 fungal structures, and 1 additional non-pollen palynomorph taxon. Red Gap had the highest species richness (S = 53) followed by Nut Beds (S = 29) and White Cliffs Jr. (S = 27). While unidentifiable pollen grains were a notable percentage of palynomorphs from each site ranging between 9% and 25.6% of an assemblage, Betulaceae and Juglandaceae were also common. Onagraceae is now recognized from the Nut Beds where no macrofossils had been recorded before. Bioclimatic Analysis revealed a mean annual temperature (MAT) of 12.4-14.1 degrees C and mean annual precipitation (MAP) of 955-1072 mm. The climatic estimates for the Nut Beds (12.4 degrees C and 955 mm) are likely underestimates of both temperature and precipitation because an analysis of combined macro- and microfossils yields a MAT of 18.5 degrees C and MAP of 1276 mm. This discrepancy may be explained by few grains being assigned to modern taxa and/or mesothermal plants tending to be more zoophilous and less likely to get preserved in the microfossil record. The Nut Beds are interpreted as a lacustrine delta due to the large amounts of dispersed cuticle, whereas White Cliffs Jr. and Red Gap are interpreted as stream-fed lake deposits. The results highlight differences in biodiversity between each locality and differences in preservational bias among different plant organs.
Diverse and rich assemblages composed of spores and organic-walled microphytoplankton are reported from 15 subsurface samples of the SM-4 well in the Llanos Orientales Basin, Colombia. The palynoflora includes 32 species of spores, 23 acritarchs and nine prasinophyte phycomata, along with nine species of chitinozoans and indeterminate scolecodonts. These are the first Late Devonian palynological assemblages to be described and illustrated in detail from Colombia. Based on global stratigraphic ranges, a Frasnian-Famennian age is proposed for the studied succession, although diagnostic late Famennian species are notably absent. Teichertospora torquata and Hystricosporites multifurcatus first occurrences allow for the assignment of the uppermost samples to the Famennian, while the presence of Ancyrospora spp., Evittia geometrica, Puteoscortum limai, Samarisporites triangulatus and Verrucosisporites bulliferus characterizes the Frasnian. Chitinozoans and acritarchs confirm a Frasnian age for most of the analyzed samples, enabling correlation with assemblages described in Brazilian basins. It is suggested that the assemblages are approximately time-equivalent to the Teichertospora torquata-Auroraspora pseudocrista (late Frasnian-late middle Famennian) and Verrucosisporites bulliferus-Geminospora piliformis (early middle Frasnian) Brazilian zones. The uppermost strata in the studied section were deposited in shoreline marine environments, while below 822.9 m, microplankton diversity indicates a transition from nearshore to offshore conditions.
The subtribe Cyclolejeuneinae (Lejeuneaceae) comprises the genera Bromeliophila, Cyclolejeunea, and Prionolejeunea. Morphological, biogeographical, and ecological evidence do not align with the well-established phylogenetic pattern of the group, particularly regarding the position of Bromeliophila. A detailed investigation of sporophyte morphology is therefore essential to clarify these still unresolved relationships. In this study, we examined the sporophytic generation using morphological and palynological approaches. Specimens were obtained through field collections and herbarium loans. The sporophyte was analyzed using light and electron microscopy, while the spores were also studied using standard palynological techniques. Our results reveal that sporophyte structure is closely linked to ecological and biogeographical patterns, reflecting evolutionary adaptations within the subtribe. Variation in key characters, such as seta length, spore size, and the number of elaters and elateroids, correlates with differences in habitat and dispersal strategy. Bromeliophila, characterized by a long seta, stipitate perianth, and large spores, shows traits consistent with rheophytic and epiphyllous habits, suggesting short-distance, animal- or water-mediated dispersal. In contrast, Prionolejeunea, with numerous elaters and small to medium spores, is adapted for wind dispersal, while Cyclolejeunea maintains a broad distribution through vegetative propagation and medium spores. These findings indicate that diversification within Cyclolejeuneinae involves evolutionary trade-offs between spore morphology and dispersal strategy, reflecting adaptations to contrasting microhabitats. The observed variation in ornamentation and elater features underscores the taxonomic and ecological significance of sporophyte morphology as a key component for understanding evolutionary trajectories in Cyclolejeuneinae and, more broadly, bryophyte evolution.
Pollen and non-pollen palynomorph data from the Isle of Mull, Inner Hebrides, Scotland, are presented from the site of Loch an t'Suidhe, a small lake on the Ross of Mull peninsula. The aim was to determine the palaeoecological record associated with early to mid-Holocene environmental change. A core was extracted from the infilled peaty margins at the southern end of the loch with an 8 cm diameter Russian-type corer. Pollen, spore, non-pollen palynomorph, microscopic charcoal and loss-on-ignition data derive from the basal part of the core. Six radiocarbon dates contribute to core chronology. Dates are calibrated using the IntCal20 calibration curve with age-depth modelling via Clam software. Palynomorph data are produced using Tilia and TGView software. The profile covers the Holocene period from an estimated 10,890-5470 calendar years BP. The data enable comparisons to be made with undated palynological profiles already available from the Isle of Mull, enhancing opportunities to explain early to mid-Holocene environmental change - which would cover the Mesolithic and early Neolithic archaeological periods - in the Inner Hebrides and beyond.
