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Characterizing the shape of pollen is crucial for plant breeding, taxonomy, and conservation, and studies on pollen viability can help breeding initiatives. This study examined the male fertility and pollen morphology of six Cucurbitaceae species with potential for both economic and nutritional benefit. Pollen grains were acetolyzed for morphological study, and a light compound microscope and an LEICA digital microscope were used to determine the exine stratification as well as other characteristics of pollen grains. The Cucurbitaceae family is eurypalynous, as evidenced by the noticeable differences in pollen physical characteristics between species. The shapes of pollen might be oblate, sub-oblate, or oblate-spheroidal. Pollen viability percentage was determined by using different staining methods- Acetocarmine test, Lugol’s test and Aniline blue test respectively. M. dioica, or spiny gourd, had the highest pollen viability percentage (94.4%), while L. acutangula, or Chinese okra, had the lowest percentage (80.83%) when it was fresh. Using Lugol's test, six Cucurbitaceae species' pollen grains were found to be starchy by nature. In Lugol's test, M. dioica showed the highest percentage of pollen viability, whereas M. charantia showed the lowest percentage of pollen viability following the anthesis of the flowers (at fresh). Species identification relies heavily on pollen morphology, particularly in this diverse family where many species exist. High viability rates encourage seed production and fertilization, which are necessary for effective hybrid development and conservation. [ABSTRACT FROM AUTHOR]

The pollen morphology of 63 species, one subspecies and six varieties of 11 genera in the family Liliaceae was studied in detail using light microscopy (LM) and scanning electron microscopy (SEM). Among them, 22 species and one variety are reported for the first time. Ten pollen characteristics (shape in polar view, ends in polar view, width of colpus, depth of colpus, length of colpus, colpus costa, colpus membranes, type of surface ornamentation, muri, lumina) were selected for cluster analysis of the genera Gagea and Lloydia and for cluster analysis and principal component analysis of the genera Lilium and Nomocharis. The results show that the polar view, colpus morphology and surface ornamentation of pollen grains have important systematic significance. The surface ornamentation of pollen grains in this study can be divided into five types, namely gemmate, reticulate, rugulate, rugulate-perforate and verrucate. In combination with the results of previous research, our results suggest that (i) Clintonia and Streptopus should be included in the family Liliaceae; (ii) Fritillaria and Lilium should be considered independent genera; (iii) Lloydia should belong to Gagea; and (iv) Nomocharis should be merged into Lilium. But our results do not support dividing Lilium into seven sections. [ABSTRACT FROM AUTHOR]

Palynology, a prominent field in plant systematics and biodiversity studies, plays a vital role in identifying and determining the plant species present in a specific region. The current study was performed to evaluate the micromorphological traits of pollen from flora of Lesser Himalaya. Pollen microstructural variations aid in the identification of species belonging to specific botanical families and various geographic habitats. Flowers of 24 selected species categorized into 16 families were collected, preserved and then acetolysis protocol followed. Pollen was examined under a light and scanning microscopy (LM and SEM) for palynomorph description. The palynomorphs characteristics such as size, shape, exine surface, and aperture orientation, were examined. Status of these plants show that herbs are being dominant (11 species), while shrubs (7 species), climbers (3 species), bulbous plants (2 species), small tree, sedge, weed (1 species each). Pollen shape determined in equatorial view were; spheroidal, sub-prolate, oblate-spheroidal, prolate, spherical and sub-oblate. The variations were seen among pollen types; tricolpate, tricolporate and polyporate in most of the species. Exine stratification was observed mostly scabrate while echinate, cristate-reticulate, granulate, punctate, rugulate-perforate, striate-rugulate, verrucate, cristate-foveolate was visualized in each different species. Palynomorph apertural patterns were observed sunken, furrowed, slightly bulged, scabrate, granulate, slit like, and perforate. The largest polar diameter was measured in Hymenocallis littoralis (138.6 µm) whereas smallest in Parthenium hysterophorus (14.70 µm). Equatorial distance was calculated maximum for Cascabela thevetia (110.1 µm) and minimum for Hibiscus rosa-sinensis (1.7 µm). P/E ratio was calculated largest in Hymenocallis littoralis (1.8) and lowest in Duranta erecta (0.89). The palynomorphs taxonomic characters investigated can be helpful in species level identification and provide a baseline to conduct more systematic research with respect to specific plant families and genera. [ABSTRACT FROM AUTHOR]

The morphology of 75 different pollen grains from 67 species of genus Solanum L., two species of genus Cyphomandra Sendt., and six species of genus Lycianthes (Dunal) Hassl. was studied using light microscopy and scanning electron microscopy. Among them, the pollen of 66 species is described for the first time. Our results suggest that the sexine ornamention of Solanum, Cyphomandra and Lycianthes is extremely similar, but the apertures of genus Solanum and Cyphomandra are not syncolpate while those of genus Lycianthes are syncolpate. Overall, we argued that the Solanum species studied demonstrated sufficient pollinic heterogeneity in their shapes, aperture feature and sexine ornamentation to enable their palynological characterisation and support the point of view that the genus Cyphomandra should be merged into Solanum, but Lycianthes should be an independent genus from the aspect of palynology. [ABSTRACT FROM AUTHOR]

Morphological observations on pollen grains of Alvaradoa subovata Cronquist (Simaroubaceae) and Roupala brasiliensis Klotzch (Proteaceae) obtained from TEM complement previous studies of Xifreda & Sanso (1998). With the aim of giving details of the morphology and accuracy to the descriptive terminology, exine stratification is described and new observations on pollen grains obtained from SEM are added. [ABSTRACT FROM AUTHOR]

This study provides pollen data for 38 representative taxa belonging to all nine genera in the current classification of the tribe Spiraeeae (Rosaceae) including the monotypic Korean endemic genusPentactina, and considers the distribution of orbicules for the first time. Pollen morphology and wall stratification were investigated using light, scanning electron and transmission electron microscopy. Spiraeeae pollen grains are small to medium in size (P = 6.9–34.0 μm,E = 7.1–28.0 μm), oblate to prolate in shape (P/E = 0.66–1.48) and tri-colporate. Spiraeeae pollen is generally characterised by striate sexine ornamentation, but four ornamentation types are recognised based on the length and direction of the ridge patterns. The observed variation in sexine ornamentation is particularly valuable at the generic level. The exine stratification of the representative Spiraeeae studied is similar and characterised by unbranched columellae and a continuous endexine. Orbicules are present in three genera of the tribe (Luetkea,SibiraeaandXerospiraea). Orbicule distribution patterns indicate that the absence of orbicules is a synapomorphic condition of the more derived clade, comprisingPentactina+Petrophytum+Kelseya+Spiraea. [ABSTRACT FROM PUBLISHER]

Palynology, a prominent field in plant systematics and biodiversity studies, plays a vital role in identifying and determining the plant species present in a specific region. The current study was performed to evaluate the micromorphological traits of pollen from flora of Lesser Himalaya. Pollen microstructural variations aid in the identification of species belonging to specific botanical families and various geographic habitats. Flowers of 24 selected species categorized into 16 families were collected, preserved and then acetolysis protocol followed. Pollen was examined under a light and scanning microscopy (LM and SEM) for palynomorph description. The palynomorphs characteristics such as size, shape, exine surface, and aperture orientation, were examined. Status of these plants show that herbs are being dominant (11 species), while shrubs (7 species), climbers (3 species), bulbous plants (2 species), small tree, sedge, weed (1 species each). Pollen shape determined in equatorial view were; spheroidal, sub-prolate, oblate-spheroidal, prolate, spherical and sub-oblate. The variations were seen among pollen types; tricolpate, tricolporate and polyporate in most of the species. Exine stratification was observed mostly scabrate while echinate, cristate-reticulate, granulate, punctate, rugulate-perforate, striate-rugulate, verrucate, cristate-foveolate was visualized in each different species. Palynomorph apertural patterns were observed sunken, furrowed, slightly bulged, scabrate, granulate, slit like, and perforate. The largest polar diameter was measured in Hymenocallis littoralis (138.6 µm) whereas smallest in Parthenium hysterophorus (14.70 µm). Equatorial distance was calculated maximum for Cascabela thevetia (110.1 µm) and minimum for Hibiscus rosa-sinensis (1.7 µm). P/E ratio was calculated largest in Hymenocallis littoralis (1.8) and lowest in Duranta erecta (0.89). The palynomorphs taxonomic characters investigated can be helpful in species level identification and provide a baseline to conduct more systematic research with respect to specific plant families and genera.

This study aimed to examine the pollen and pollinia morpho-structure of 18 horticultural Apocynaceous species. Advanced light and scanning electron microscopy (LM and SEM) were used to elaborate on and examine the systematic importance of pollen and pollinia micromorphology. Pollen grains were first acetolysed, which was followed by visualisation of their sculpturing features. The quantified data were subjected to statistical tools to elucidate dendrogram clustering and principal component analysis to reveal pollen/pollinia morphotypes. The size of pollen is variable, ranging from 113.45 μm in Cascabela thevetia to 23.4 μm in Alstonia scholaris. The study revealed tetrad, tetraporate, and tricolporate grains. Sculpturing (exine ornamentation) varies from reticulate perforate to reticulate. Pollinum shape was observed to be narrow oblong, obovate, orbicular, and reniform. Reticulate-psilate sculptural features were prominent among pollinia surfaces. Based on examination, it was ascertained that the minimum exine thickness in Periploca aphylla was 4.9 μm, whereas the corresponding number in Cryptolepis dubia was 1.35 μm. Taxonomic identification keys were constructed separately based on pollen/pollinia characters to identify the Apocynaceous taxa. In the presented study, seven pollen shapes were observed: from oblate to per prolate. The findings confirm that morphopollinic traits differ amongst genera of Apocynaceous species. However, these features can be used to distinguish the Apocynaceous taxa. The results show that structural characteristics of pollen and pollinia can help accurately identify Apocynaceous species. [ABSTRACT FROM AUTHOR]

Scanning microscopic imaging has become a valuable research tool in micromorphology with improved techniques playing an important role in analysing the ultrastructure of leaf specimens. The foliar epidermal anatomy of 25 selected poisonous plants with special emphasis on stomata and trichomes was reported using microscopic techniques, for instance, light micrographs (LMs) and scanning micrographs (SEMs). This study aimed to investigate micromorphologies of studied species that are helpful for the identification of poisonous plants. Plants were collected, pressed, dried, identified and then analysed for microscopic study. For making microscopic slides, 1 or 2 leaves were taken in a test tube and dipped in 30% nitric acid and 70% lactic acid for few minutes, and then placed on petri plates for separating the epidermis. Numerous quantitative and qualitative foliar anatomical features of adaxial and abaxial surfaces, including epidermal cell shapes, stomata size, subsidiary cell size, the pattern of the anticlinal wall, the morphology of the stomatal complex and trichome diversity, were examined. A small number of the considered species had anomocytic and anisocytic stomata; a few species had paracytic stomata, for instance, Ricinus communis, Euphorbia royleana, Buxus pilosula and Sorghum halepense; and only Ipomoea carnea had cyclocytic stomata in the studied taxa. The epidermal cells of the analysed species were irregular, while some exhibited polygonal, wavy, tetragonal and elongated cell morphologies. Overall, this study emphasises the significance of foliar micromorphology analysis as a valuable resource for identifying potentially poisonous plants and demonstrates its contribution to maintaining public welfare, thereby benefitting public health and safety. [ABSTRACT FROM AUTHOR]

The present study was carried out to investigate the pollen morphology of eight taxa of Tephrosia, namely T. falciformis. T. purpurea subsp. leptostachya, T. purpurea subsp. purpurea, T. subtriflora, T. strigosa, T. uniflora subsp. petrosa, T. villosa and T. wallichii occurring in Indian Thar desert. Safranin-stained and acetolysed pollen grains were used to describe their morphology. The pollen characters investigated include pollen size, shape, polarity, symmetry, aperture type and exine ornamentation. The pollen grains are monads, small (10-25 µm) to medium (25-50 µm), isopolar and radially symmetrical; they are smallest in T. strigosa and biggest in T. purpurea subsp. leptostachya. The exine ornamentation varies from reticulate, micro-reticulate, rugulate-reticulate and foveolate to foveolate-reticulate. A taxonomic key is provided based-on pollen to discriminate Tephrosia taxa investigated. [ABSTRACT FROM AUTHOR]

Pollen morphology of a total of 25 species ofErica(23 species) and its closely related generaCalluna(monotypic) andDaboecia(monotypic) was examined by means of light and scanning electron microscopy (SEM), or SEM alone. The pollen tetrads ofE. multifloraandE. trimerassp.keniensis, and monads ofE. barbigeroidesandE. recurvifolia, were examined with transmission electron microscopy to study the exine stratification. The quantitative features ofEricapollen have varied widely. However, the exine sculpture ofEricapollen is often characterised by the presence of numerous minute granules as secondary sculpture.Callunapollen is characterised by irregular tetrads and perforated septum, and theDaboeciapollen tetrads by larger values of theD/d,P/Eand 2f/Dratios. TheP/Eratio and exine architecture showed distinct differences betweenEricamonads and tetrads. Among theEricaspecies having pollen tetrads, two distinctly different palynomorphological groups could be identified based on the 2f/Dratio. Two distinct groups could also be differentiated on the basis of theL/Pratio within theEricaspecies producing monads. Palynological characters, therefore, might be featured as a useful tool to clarify infrageneric classification system for the large genusErica. [ABSTRACT FROM PUBLISHER]

The pollen grains of 38 species and one variety of 17 genera in the family Solanaceae were studied using light microscopy (LM) and scanning electron microscopy (SEM). Among them, the pollen morphology of 13 species was described for the first time. Our results suggested that the exine ornamentation of pollen grains could be divided into 11 types, made up of three types (cerebroid, granulate-perforate-punctate and rugulate-perforate) which were observed for the first time in Solanaceae, and other normal types (granulate, granulate-perforate, punctate, reticulate, rugulate, rugulate-striate, spinulose-perforate, striate). In addition, the studied species have pollen grains that differ in size, shape, equatorial view, polar view, aperture features and exine ornamentation, confirming that Solanaceae is a eurypalynous family. Furthermore, the intergeneric and intrageneric relationships of Solanaceae were explored. These results could provide a palynological basis for classification and systematic study of Solanaceae. [ABSTRACT FROM AUTHOR]

The pollen morphology of subtribe Menthinae sensu Harley et al. [In: The families and genera of vascular plants VII. Flowering plants·dicotyledons: Lamiales (except Acanthaceae including Avicenniaceae). Springer, Berlin, pp 167–275, ] and two genera of uncertain subtribal affinities ( Heterolamium and Melissa) are documented in order to complete our palynological overview of the tribe Mentheae. Menthinae pollen is small to medium in size (13–43 μm), oblate to prolate in shape and mostly hexacolpate (sometimes pentacolpate). Perforate, microreticulate or bireticulate exine ornamentation types were observed. The exine ornamentation of Menthinae is systematically highly informative particularly at generic level. The exine stratification in all taxa studied is characterized by unbranched columellae. Orbicules are consistently absent in Menthinae. Our palynological data are interpreted in a phylogenetic context at tribal level in order to assess the systematic value of pollen characters and to evaluate the existing molecular phylogenies for this group. Pollen morphology suggests Heterolamium as a close relative of subtribe Nepetinae and supports the molecular affinity of Melissa to subtribe Salviinae. [ABSTRACT FROM AUTHOR]

The structure of the pollen of 42 species of Pseuduvaria (Annonaceae) is described. The pollen is consistently inaperturate, isopolar and radially symmetrical. Four basic patterns of exine sculpturing are identified: rugulate, verrucate, scabrate and psilate. The exine stratification of one representative species, P. macrocarpa , is shown to be entirely ectexinal. The ectexine consists of a discontinuous outer tectal layer, a columellar infratectal layer, and an inner lamellar foliated foot layer; the intine is very thin and fibrillar. The pollen is invariably released as acalymmate tetrads, in which the tectum is absent from the proximal walls. The individual pollen grains within the tetrads are connected by crosswall cohesion, involving both exine and intine; this form of cohesion has not hitherto been reported in the Annonaceae. In addition, pollen grains of neighbouring tetrads are connected in two different ways, viz. short exine connections and non-sporopollenin pollen-connecting threads. Neither of these cohesion mechanisms has previously been reported for the genus. The function of the various forms of cohesion between pollen grains and tetrads in Pseuduvaria is discussed as a mechanism to enhance the efficiency of pollination by enabling the fertilization of multiple ovules following a single pollinator visit. © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 69-78. [ABSTRACT FROM AUTHOR]

Reinvestigates the pollen characters of Amborella trichopoda. Pollen morphology; Comparison of pollen characters with those of other basalmost angiosperms; Exine stratification; Pollen wall in the nonapertural area; Pollen wall close to and in the apertural area; Aperture location and configuration.

Due to the diverse and rich taxa, Asteraceae needs to explore from the untouched area. In this study, the pollen study was intended to assess the taxonomic value for Asteraceous taxa growing on the Sikaram Mountain Pak‐Afghan border. Both microscopic techniques (LM and SEM) play a significant role in the identification and classification of herbaceous species of Asteraceae for their taxonomic and systematic implication. Pollen was observed and measured for the 15 species of Asteraceae. For investigated taxa 15 pollen characters with size, shape, polar view, pollen type, aperture orientation, and exine sculpturing in the eurypalynous pollen. Consequently, the pollen grains are usually Tricolporate, triangular to circular in polar view, while, the shape of pollen varies from subulate, oblate, and prolate along with prolate to spheroidal whereas, sculpturing also varies from Scabrate to micro reticulate, echino‐perforate, Scabrate to echinate, echinate to granulate and echinate were observed. Similarly, among the quantitative data minimum values of polar and equatorial were 15.8 ± 0.74 μm in Filago pyramidata and 17.85 ± 0.39 μm in Heteropappus altaicus was measured respectively, while; the length of the spine with the least value of 2.45 ± 0.31 μm in Hertia intermedia and highest with 7.55 ± 0.31 μm was observed in Cirsium wallichii. The Exine thickness is a minimum of 1.70 ± 0.35 μm in Launaea nudicaulis and a maximum of 5.65 ± 3.59 μm in Cirssium vulgare. In addition, the highest pollen fertility (87%) in Centaurea iberica while the highest pollen sterility (32%) was recorded in Cirsium verutum. Furthermore, clustering via UPGMA, PCA, and PCoA analysis was performed for the separation of closely related taxa. It is concluded from this research work that palynological study has a crucial role in taxonomic, pure, and applied sciences. This study can be further authenticated and improved by a Phylogenetic study based on chloroplast DNA analysis & whole genome sequencing. Research Highlights: Pollen ultrastructure among 15 Asteraceous taxa.Micromorphological attributes measured via LM and SEM.Exine sculpture elements patterns provide accurate identification.Taxonomic keys were developed for its systematics implications. [ABSTRACT FROM AUTHOR]

Southern Patagonia contains several Eocene fossiliferous deposits that have only been superficially explored and studied. One of these corresponds to the La Marcelina Formation with outcrops in the south-western slope of the Deseado Massif, Santa Cruz Province, Argentina. No detailed palynological studies have been performed so far in this unit. Here we estimate the age, palaeoenvironment, and climatic conditions based on the analysis of terrestrially derived spores, algae cysts, and pollen grains. The recovered association supports an Eocene age and concurs with a mixed flora, including Gondwanan and Neotropical elements, dominated by Podocarpaceae, Nothofagaceae, and Proteaceae, and that probably developed under a temperate and humid climate. Overall, these results expand our understanding of the composition of Eocene floras from the highest latitudes of South America, as well as provide new evidence of past paleoclimates for the area. [ABSTRACT FROM AUTHOR]

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Serra dos Carajás harbors a unique open plant community in Amazonia, known as canga vegetation, with several endemic species coexisting with the potential threat of large-scale iron ore mining. In this sense, Convolvulaceae occur in a wide variety of canga geoenvironments with multiple flower visitors, but the scarcity of data on its pollen morphology prevents the correct association between Convolvulaceae species with floral visitors, as well as the precise identification of their habitats throughout the Quaternary. Therefore, this study aims to contribute to the taxonomic knowledge and refinement of the identification of insect-plant networks of endangered plants, including Ipomoea cavalcantei. Pollen grains were examined by light and scanning electron microscopy (LM and SEM, respectively), and the morphological parameters obtained were statistically analyzed using principal component analysis. Therefore, all species were differentiated based on aperture types and exine ornamentation. The set of morphological characters indicated that echinae morphology, easily identified under LM, was effective for the identification of Ipomoea species. This work represents the first robust pollen database for a precise identification at the species level of Convolvulaceae from southeastern Amazonian cangas. [ABSTRACT FROM AUTHOR]

Coussareeae is a neotropical tribe with a complex taxonomic history. Several authors considered it very close to the tribe Psychotrieae owing to similarities in their morphological characteristics, such as solitary ovules. The tribe Coussareeae constitutes the largest basal clade of the subfamily Rubioideae, and most of its genera are well represented in Brazil. The tribe is resolved into three suprageneric clades, including the Coccocypselum and Coussarea-Faramea clades, whose representatives are found in Brazil. This study aimed to ascertain whether pollen attributes corroborate the currently proposed phylogeny and systematics of the tribe. For this, pollen grains of 33 species belonging to the Coccocypselum and Coussarea-Faramea clades were analyzed. Specimens were obtained from herbaria, treated by the acetolysis method, measured, photographed, and described using light and scanning electron microscopy. Morphological analysis showed that pollen grains were medium (25–50 µm) or large (50–100 µm) in size; isopolar or apolar; 2-porate, 3-porate, or 3-colporate; and oblate spheroidal, suboblate, prolate spheroidal, or subprolate. Ornamentation varied among clade representatives. Multivariate analysis of quantitative data revealed that pollen diameter, apocolpium side, pore diameter, colpus length, and endoaperture width were the most significant characters. It can be seen from the results that the studied clades are formed by palynologically distinct genera in terms of polarity, aperture type, and ornamentation. Palynology confirms the proposed taxonomic classification. [ABSTRACT FROM AUTHOR]

In this study, detailed light microscopy (LM) and scanning-electron microscopy (SEM) analyses of pollen grains belonging to 11 taxa of genera Grammosciadium, Vinogradovia and Caropodium were performed. The pollen is radially symmetrical and generally isopolar with the exception of Grammosciadium macrodan ssp. nezaketiae where 65% of the grains have asymmetrical appearance. All the taxa are tricolporate. Ectoapertures are discontinuous (colpus length: 14.7 ± 0.8 and colpus width: 21.20 ± 2.28) with narrow and acute at the ends extending to the subpolar region. Endoapertures are in the mid-section of the ectoapertures, which is lolangate, prolate-spheroidal in Grammosciadium scabridum, while lalongate, ellipsoidal, oblate or suboblate in the other taxa. Pollen shape is triangular and semi-triangular in polar-view. Pollen outline in equatorial view is subrectangular-straight in G. scabridum and Caropodium platycarpum, however, those were subrectangular and slightly constricted in equatorial region in all others. Based on the P/E ratio, it is prolate in G. macrodon ssp. macrodon while it is perprolate in the other taxa. Ornamentation variation (i.e. psilate, psilate-perforate, psilate-rugulate, rugulate and rugulate-perforate) was observed around the apertural, equatorial and polar regions. This character has been found as taxonomically important for the studied taxa. [ABSTRACT FROM AUTHOR]

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 re-evaluation 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. [ABSTRACT FROM AUTHOR]

The article discusses the evolution and development of pollen wall patterns. Topics discussed include the specialized outer cell wall of pollen grains, known as the exine and is composed of highly resistant polymer sporopollenin, exhibits enormous organizational diversity; sequence of genes expressed during microsporogenesis to the interactions between gene products; and pollen wall mimics that are generated by the biophysical process of self-assembly.

The legume genus Parkia R.Br. has a pantropical distribution and centre of diversity in the Amazon. The molecular phylogeny of the group indicates a Neotropical origin in the Amazon biome during the Miocene, and habitat reconstruction points to terra firme (unflooded) forests. We examined recently described fossil pollen from the Miocene Solimões Formation in western Brazilian Amazonia attributed to this genus. Aiming to establish an infra-generic affinity, comparisons were performed between fossil pollen of Parkiidites marileae Leite and pollen from extant Parkia species using morphological characters and multivariate analyses. Parkiidites marileae is characterised by large and globose polyads, the polyads are composed of 16 monads, and the monads have a verrucate ornamentation. Analyses suggest two well-defined groups, a non-NLR (nearest living relative) group composed of P. decussata, P. gigantocarpa, P. velutina, P. panurensis, P. platycephala, P. pendula, P. multijuga, and P. ulei; and a NLR group composed of P. cachimboensis, P. discolor, P. igneiflora, P. lutea, and P. nitida. All species of the NLR group belong to the same clade, with a molecular age estimated at ∼12.8 million years, which is virtually the same age as interpreted for the first occurrence of P. marileae in the Solimões Formation. The late Middle to Late Miocene in western Amazonia was a time of gradual change from vast wetlands to more river-dominated landscapes that favoured unflooded forests where Parkia diversified and is distributed today. [ABSTRACT FROM AUTHOR]

Rauvolfia belongs to the family Apocynaceae and encompasses herbs or shrubs with leaves in whorls of three or four. It is an endangered plant of the tropics and subtropics. We present a preliminary study and analysis of the morphological details of the pollen of two extant species of Rauvolfia (R. serpentina (L.) Benth. ex Kurz and R. tetraphylla L.) from the Ganga Plain using light microscopy (LM), confocal laser scanning microscopy (CLSM) and field emission scanning electron microscopy (FESEM). The critical point drying method (CPD) was adopted to test the pollen size difference from the conventional acetolysis method (ACE). The pollen morphology of R. tetraphylla differs from that of R. serpentina in several specific traits. Its pollen grain is 3-colporate; it is oblate to oblate-spheroidal; sexine is punctate to obscure and mostly as thick as nexine; and a distinct thickening is present around the ectocolpi. The study shows that R. serpentina can be distinguished from R. tetraphylla by its pollen shape, size, sexine ornamentation (particularly the presence and absence of punctae/perforations in the mesocolpial region) and length of the ectocolpi thickening. The pollen shape and aperture number are more or less common features in Rauvolfia spp., but the presence and absence of a punctate pattern at the mesocolpial position marks the primary difference between the two species. The t-test was applied to determine the statistical significance of pollen morphological data of both species. This study provides a source of information for systematic and conservation purposes and provides a baseline to facilitate palynological studies of past vegetation and palaeoenvironments. [ABSTRACT FROM AUTHOR]