BACKGROUND:Multilamellated zones (MZs) are small areas in the innermost portion of sporopollenin-containing walls of spores of heterosporous lycopsids, where this layer of the sporopollenin wall becomes thicker by splitting into interconnected lamellae. The detection of MZs is difficult, but accumulating information on their occurrence suggests possible evolutionary and taxonomic importance, requiring updating and re-evaluation. SCOPE:The paper reviews the occurrences of MZs in spores of fossil and extant lycopsids (since the Devonian to modern times). The majority of MZ records are ascribed with different degrees of certainty to the isoetalean lineage, but they are also observed in some members of Selaginellales. The only known homosporous plant with MZs is the Early Devonian Leclercqia. As to modern Isoetes and Selaginella, some species of these genera possess MZs, but only in microspores. It is still unclear when megaspores lost MZs and whether this was a single event. The available information is incomplete: ultrastructural characteristics are available for microspores of several taxa of fossil heterosporous lycopsids, but there is a lack of data on their megaspores. CONCLUSIONS:The occurrence of MZs almost exclusively in heterosporous lycopsids and their consistent presence in isoetaleans are begging for phylogenetic interpretation, but their occurrence in some species and absence in other species of the same genera and especially the dearth of relevant information on many heterosporous lycopsids warrant cautious interpretation. The location of MZs only in the vicinity of the haptotypic mark and the fact that they appeared as early as the Devonian and are still present in extant species suggest that they have some function. Although the most widely circulated hypothesis relates them to spore germination, no confirmation has been obtained so far from extant species.

Populus is the most genetically studied woody plant. Its pollen is highly distinctive. The sporoderm development from meiosis to mature pollen grains has not been studied for any Populus species. Here we present a detailed ontogenetic study with dates and durations of all stages of sporoderm development for Populus species growing in the Moscow region. They are one native species (Populus tremula), one introduced species (Populus alba), and two widespread cultivars (Populus x nevensis and Populus x berolinensis). Pollen development of P. alba, P. x nevensis, and P. x berolinensis is two weeks earlier than that of P. tremula. Simultaneous meiosis in Populus takes place in late February-early March. It lasts for about a week. In one month the pollen grains mature. The most rapid are the stages of the tetrad period. Orbicules and a peritapetal membrane have been found in the plasmodial tapetum. A thin and often intermittent two-layered exine is formed along the entire circumference of the pollen grain. A tectum (with nanoechini and perforations), columellae and a thin foot layer form the ectexine. The endexine consists of short, thick lamellae. The formation and maturation of all five layers takes one to two weeks. The two-layered intine is the thickest sporoderm layer. Its development takes two to three weeks. Tubular elements are found in the outer intine, making the intine similar to the aperture membrane. Morphologically, Populus pollen grains are inaperturate in the exine and omniaperturate in the intine.

In flowering plants, reactive oxygen species (ROS) are actively involved in the regulation of sexual reproduction. Here we present the first evidence on the participation of ROS in sexual interactions in coniferous plants. In most gymnosperms, pollen hydrates and germinates in a pollination drop—a special type of ovular secretion. We studied the composition of this liquid for four conifer species from three families for the presence of ROS using the most sensitive method for detecting low concentrations of ROS—EPR (electron paramagnetic resonance) spectroscopy. ROS were present in pollination drops of all the plants studied, however, the composition of ROS was different: in Taxus, Pinus and Picea the main form was O⋅2−, in Thuja it was H2O2, reaching values comparable to stigma exudates of flowering plants. We tested the potential involvement of superoxide in the regulation of spruce pollen germination in vitro and found a strong stimulating effect on both total and bipolar germination efficiency. Thus, we found that conifers are characterized by the presence of ROS in the liquid intended for pollen germination, as well as in flowering plants. Hydrogen peroxide and superoxide radical, apparently represent a variety of ROS-based mechanisms for the regulation of pollen germination in vivo.

Grasses (Poaceae) produce large amounts of pollen and are among the main causes of pollinosis worldwide. Despite their morphological similarity, pollen grains of different grass species may have different allergenicities. Therefore, quantification of the roles of individual species in airborne pollen is an important task. There are very few studies on this topic, and none of them have been conducted in a temperate continental climate. Our study was carried out for three years (2020–2022) in the urban territory of Moscow (Russia) and aimed to understand what grass species contribute the most to the total pollen load of the atmosphere. The comparison of aerobiological and phenological data was based on calculating the phenological index, which is a combination of phenological parameters, pollen productivity of individual species, and their abundance. Our data showed that the decomposition of pollination curves based on the phenological index was sometimes very efficient but not always possible in temperate continental climates. The main reasons for disagreement between aerobiological and phenological data were weather conditions and lawn mowing. Not all grasses were equally important as sources of allergenic pollen. The greatest contribution to the pollen load at the beginning of the season in Moscow was made by Dactylis glomerata, and to a lesser extent by Phleum pratense and Festuca pratensis. These are the most common species, which are widespread throughout Europe. The contribution of minor components is insignificant.

This paper describes a range of Paleozoic and Mesozoic mosses and assesses how far they can be referred to extant taxa at the family, ordinal, or class levels. The present study provides new data on Paleozoic mosses of the order Protosphagnales, re-evaluating affinities of some groups previously thought to be unrelated. The leaf areolation pattern, combined with the leaf costa anatomy, results in the subdivision of Protosphagnales into five separate families: Protosphagnaceae (at least six genera), Polyssaieviaceae (at least three genera), and three monogeneric families: Rhizonigeritaceae, Palaeosphagnaceae, and Servicktiaceae. We urge caution in referring Paleozoic and Early Mesozoic fossil mosses as members of Dicranidae and Bryidae, as they may belong to the extinct moss order Protosphagnales. Additional evidence supports the relation of the Permian genus Arvildia to extant Andreaeopsida. We segregate Late Palaeozoic and Early Mesozoic mosses that are superficially similar to extant members of either Dicranales or Polytrichales, into the artificial informal group of Archaeodicranids, distinguishing them from ecostate Paleozoic and Mesozoic mosses, which are combined here into another artificial informal group, Bryokhutuliinids. The latter includes the genus Bryokhutuliinia, widespread in contemporary Asia, from the Middle Jurassic to the Lower Cretaceous, as well as other superficially similar ecostate plants from different regions worldwide, ranging from the Upper Palaeozoic to the Lower Cretaceous. A list of Paleozoic, Mesozoic, and Eocene moss fossils suitable for age calibration in phylogenetic trees is provided.

MAIN CONCLUSION:Our findings suggest a reconsideration of pollen wall ontogeny process, entailing examination of physical factors, which enable a new understanding of exine developmental processes as self-formation. The pollen wall, the most complex cell wall in plants, is especially interesting as a model of ontogeny in miniature. By a detailed study of each developmental stage of Campanula rapunculoides pollen wall, we aimed to understand the establishment of complex pollen walls and the underlying developmental mechanisms. Other aim was to compare our current observations with studies in other species to reveal the common principles. We also tried to analyse the reasons for commonalities in ontogenies of exines in remote species. TEM, SEM, comparative methods were used in this study. The sequence of events leading to exine emergence from early tetrad stage to maturity is as follows: the appearance of spherical micelles in the periplasmic space and de-mixing of the mixture in periplasm (condensed and depleted layers); appearance of plasma membrane invaginations and columns of spherical micelles inside condensed layer; appearance of rod-like units, pro-tectum and thin foot layer; the appearance of spiral substructure of procolumellae and of dendritic outgrowths on the tops of procolumellae, of vast depleted zone in aperture sites; formation of the endexine lamellae on the base of laminate micelles; gradual twisting of dendritic outgrowths (macromolecule chains) into clubs on the tops of columellae and into spines; final sporopollenin accumulation. Our observations are consistent with the sequence of self-assembling micellar mesophases. Complex organisation of the exine is established through processes of self-assembly operating together with another physical process-phase separation. After genomic determination of the exine building substances, purely physical processes which are not under direct genomic control play an important role after genomic control of constructive substances. The comparison of the underlying mechanisms of exine development in remote species occurred to be general and similar to crystallisation. Our ontogenetic experience has shown the commonality of pollen wall ontogenies in remote species.

Alexey Borisovich Shipunov Alexey Shipunov was an outstanding person in many ways. An accomplished botanist, he was also a programmer and a teacher. One of his many impressive features was his universality. Indeed, he was interested in a vast range of things, and his professional scope accordingly tended to be universal: for example, as a taxonomist, he studied a few groups of plants, but, unlike almost any taxonomist today (and like Linnaeus), he was keenly interested in the global system of life, and had his own opinion about how it should look like. Alexey was born and grew up in Moscow. He graduated from the Department of Higher Plants, Faculty of Biology, Lomonosov Moscow State University, in 1990. In 1998, he defended his candidate of sciences (PhD) thesis on taxonomy of the genera Plantago L. and Psyllium Mill. (Plantaginaceae) in European Russia and adjacent areas. Alexey’s thesis was supervised by Professor Vadim Nikolayevich Tikhomirov, who at that time was the head of the Department of Higher Plants. Having spent some years after his PhD in Moscow with no success in getting a research or teaching position at the University, in 2002–2003, he moved for a year to Kew Gardens, United Kingdom, then briefly returned to his hometown, and finally emigrated to the United States in 2006. He worked first at the university of another, much smaller, Moscow (Idaho), then in Woods Hole, Massachusetts, and then in Minot, North Dakota, where he got his tenure. However, restless as he was, in 2019, Alexey left the USA for a temporary position at Kyoto University, Japan. Kyoto was his last place of residence. During his last few years, he travelled all around Japan, from Hokkaido to Okinawa, but mainly lived in the Old Capital. Alexey dedicated much of his time to education. He was a long-time member of the organising committee of the most informal of Russian biology contests for school students, the School Biology Olympics at Moscow State University. He taught at Moscow South-West High School No. 1543 (1992 – 2006), where he established a system of scientific projects for children of the specialised biology class; both the class and the system survived to this day. Alexey also taught in each of the several universities where he worked. Additionally, he recorded a lot of short educational videos for YouTube, and even during the last evening of his life he was preparing for an online lecture for students of Moscow University. Alexey was also into programming and considerably helped to develop and popularise the R software environment, which is widely used among researchers worldwide. Alexey published a series of manuals on employment of this programming language in biological studies. Alexey travelled across the world to study the flora of all its regions. One of his most impressive accomplishments was the re-discovery (together with his daughter, Ekaterina) of the poorly known plant Haptanthus Goldberg & C. Nelson in Honduras described as recently as in 1989. The plant was known from a few poorly preserved herbarium specimens, and its phylogenetic position and floral morphology remained unclear. Alexey’s re-discovery was instrumental in establishing the actual phylogenetic and structural relationships of this enigmatic and highly endangered monospecific genus. A video of his seminar talk on Haptanthus is available (see https://msu-botany.ru/ seminar-biology-2020/). The list of publications by Alexey provided here (Electronic appendix) and mainly compiled by himself demonstrates the enormous diversity of his scientific interests. He was always interested in any new techniques and ideas and, most importantly, had a unique and extremely broad knowledge of literature and scientific problems. Apart from his books, papers and other traditional publications, Alexey left some web resources, including two highly important and widely used ones: his Manual for the Plants of the World (http://herba.msu.ru/shipunov/school/f/index.htm) and the Flora and Fauna fundamental electronic library (http:// herba.msu.ru/shipunov/school/sch-ru.htm). Alexey Shipunov's materials (http://herba.msu.ru/ shipunov/index-en.htm) include diverse information that will be of continuous use for many teachers and researchers in biology. In particular, they comprise a series of versions of Alexey’s classification of flowering plants. This classification continuously was in the focus of Alexey’s interest. It provides an example of his ability to go against the mainstream. While nearly all the current classifications are illustrated or can be illustrated by cladograms, he continued the tradition of presenting a diagram of taxonomic relationships in the form of a two-dimensional map. This tradition was introduced in the 18th century by Paul Dietrich Giseke (inspired by Carl Linnaeus) and developed in the 20th century by Rolf Dahlgren. Alexey’s choice is related to the fact that, in the time of almost universal dominance of the cladistic concept of monophyly, he continued accepting paraphyletic taxa. In doing this, he followed the views of several major taxonomists of the 20th century, such as Armen Takhtajan, Arthur Cronquist, Rolf Dahlgren, and Robert Thorne. At the same time, he was using, as much as possible, any new pieces of phylogenetic evidence, including, of course, the molecular ones. As a result, Alexey’s system provides a unique opportunity to observe the pure impact of molecular data on angiosperm taxonomy because the classification of the Angiosperm Phylogeny Group incorporated changes made according to the new molecular evidence as well as the cladistic interpretation of the idea of monophyly. Alexey’s diagram of classification (Fig. 2) can be used as a modern analogue of the famous Dahlgrenograms. The Flora and Fauna fundamental electronic library is one of the parts of Alexey’s heritage that will save the memory about him for a long time. In this project, which was upheld without any funding but with the enthusiastic help of numerous colleagues from various cities and countries, Alexey managed to compile an outstanding collection of literature on the biodiversity (and related topics) of the countries of the former Soviet Union. It is difficult to imagine any formally organised programme that has achieved a comparable enormous outcome. Apart from the pure scientific value, this library, and entire life of Alexey, served to save the remains of the Soviet scientific community and to maintain scientific links between experts in natural history from different countries. We will remember Alexey as a lively, bright, and kind person. For example, we will remember his self-ironic story about how he came to the Botanical Congress in Melbourne and rented a car. “I’m driving out of the airport and I see something is wrong; everyone is driving towards me. Oh… In Australia, you drive on the left side of the road.” Alexey died last year: he drowned while swimming in the Pacific Ocean near the coast of the Miyazaki Prefecture, Kyushu Island, Japan. We, his colleagues, lost in him a dear friend and a priceless source of knowledge. We will miss him, and will try to do our best to preserve his heritage.

Grass pollen is one of the leading causes of pollinosis, affecting 10–30% of the world’s population. The allergenicity of pollen from different Poaceae species is not the same and is estimated from moderate to high. Aerobiological monitoring is a standard method that allows one to track and predict the dynamics of allergen concentration in the air. Poaceae is a stenopalynous family, and thus grass pollen can usually be identified only at the family level with optical microscopy. Molecular methods, in particular the DNA barcoding technique, can be used to conduct a more accurate analysis of aerobiological samples containing the DNA of various plant species. This study aimed to test the possibility of using the ITS1 and ITS2 nuclear loci for determining the presence of grass pollen from air samples via metabarcoding and to compare the analysis results with the results of phenological observations. Based on the high-throughput sequencing data, we analyzed the changes in the composition of aerobiological samples taken in the Moscow and Ryazan regions for three years during the period of active flowering of grasses. Ten genera of the Poaceae family were detected in airborne pollen samples. The representation for most of them for ITS1 and ITS2 barcodes was similar. At the same time, in some samples, the presence of specific genera was characterized by only one sequence: either ITS1 or ITS2. Based on the analysis of the abundance of both barcode reads in the samples, the following order could describe the change with time in the dominant species in the air: Poa, Alopecurus, and Arrhenatherum in early mid-June, Lolium, Bromus, Dactylis, and Briza in mid-late June, Phleum, Elymus in late June to early July, and Calamagrostis in early mid-July. In most samples, the number of taxa found via metabarcoding analysis was higher compared to that in the phenological observations. The semi-quantitative analysis of high-throughput sequencing data well reflects the abundance of only major grass species at the flowering stage.

New collections of a Late Paleozoic moss Arvildia allowed us to circumscribe its morphology more precisely than it has been done earlier.Despite of the compression type of the material preservation, it was possible to embed the material from bulk maceration in epon-araldite resin and study it by a series of thin and ultrathin sections with light and transmission electron microscopy.The weakly differentiated leaf costa in the transverse section and thick-walled and strongly bulging leaf cells support possible relationships of Arvildia with Andreaeopsida rather than with Dicranidae, as it was supposed earlier.This study also shows that the cell damage differs in different parts of leaf and therefore such studies of compression highlight some biomechanical properties of moss leaves. РезюмеНовые коллекции верхнепалеозойского мха из рода Arvildia позволили описать его морфологию более точно, чем это было сделано ранее.Несмотря на компрессионный тип сохранности материала, было возможно после объемной мацерации залить его в эпон-аралдитовую смолу, сделать тонкие и ультратонкие срезы и изучить их с помощью световой и электронной трансмиссионной микроскопии.Такие признаки, как слабо дифференцированная на поперечном срезе жилка и клетки с сильно выпуклыми стенками, свидетельствуют скорее в пользу гипотезы о родстве Arvildia с Andreaeopsida, чем с Dicranidae, как предполагалось ранее.Было также показано, что повреждение клеток

Quercus (oaks) is a large and important genus of woody angiosperms occurring in a wide range of environments and often occupying a dominant position in temperate forests of the Northern Hemisphere or being a minor component in some subtropical and tropical forests. A reliable determination of fossil dispersed oak pollen requires combined light, scanning electron (SEM) and transmission electron microscopy (TEM) studies and relevant comparative data on extant oak species. We provide SEM and TEM data on 22 extant Quercus spp., representing all sections of the genus. The main objectives of our study were to clarify the nature of the so-called geniculus, a characteristic equatorial bulge in the exine of the colpus found in many oak species, and to test previous hypotheses about the structural basic units of the exine in Quercus. Our ontogenetic study and oxidative experiment involving several Quercus spp. and one Trigonobalanus sp. resulted in a more accurate interpretation of the nature of the geniculus and exine elements, their different developmental states and, therefore, their more reliable application in the systematics and evolution of the genus Quercus and Fagaceae in general.

Grass pollen is one of the major causes of allergy. Aerobiological monitoring is a necessary element of the complex of anti-allergic measures, but the similar pollen morphology of Poaceae species makes it challenging to discriminate species in airborne pollen mixes, which impairs the quality of aerobiological monitoring. One of the solutions to this problem is the metabarcoding approach employing DNA barcodes for taxonomical identification of species in a mix by high-throughput sequencing of the pollen DNA. A diverse set of 14 grass species of different genera were selected to create a local reference database of nuclear ITS1, ITS2, 5′-ETS, and plastome trnL-F DNA barcodes. Sequences for the database were Sanger sequenced from live field and herbarium specimens and collected from GenBank. New Poaceae-specific primers for 5′-ETS were designed and tested to obtain a 5′-ETS region less than 600 bp long, suitable for high-throughput sequencing. The DNA extraction method for single-species pollen samples and mixes was optimized to increase the yield for amplification and sequencing of pollen DNA. Barcode sequences were analyzed and compared by the barcoding gap and intra- and interspecific distances. Their capability to correctly identify grass pollen was tested on artificial pollen mixes of various complexity. Metabarcoding analysis of the artificial pollen mixes showed that nuclear DNA barcodes ITS1, ITS2, and 5′-ETS proved to be more efficient than the plastome barcode in both amplification from pollen DNA and identification of grass species. Although the metabarcoding results were qualitatively congruent with the actual composition of the pollen mixes in most cases, the quantitative results based on read-counts did not match the actual ratio of pollen grains in the mixes.

We used the enzyme-linked immunosorbent assay (ELISA) to assess the level of endogenous hormones in spruce pollen, and immunolocalization and confocal microscopy to study hormone localization in spruce and tobacco pollen. During pollen activation, the levels of ABA, zeatin, and its riboside significantly decreased. After the initiation of polar growth, the levels of all cytokinins increased sharply; ABA level also increased. In dormant spruce pollen grains, zeatin and ABA were localized uniformly throughout the cytoplasm. Zeatin was not detected in the nuclei, and the antheridial cell showed higher levels than the vegetative cell; ABA signal was detected in the cytoplasm and the nuclei. In germinating pollen, both hormones were detected mainly in plastids. The similar pattern was found in growing pollen tubes; signal from ABA also had a noticeable level in the cytosol of the tube cell, and was weaker in the antheridial cell. Zeatin fluorescence, on the other hand, was more pronounced in the antheridial cell. In non-germinated grains of tobacco, zeatin was localized mainly in organelles. ABA in dormant pollen grains demonstrated uniform localization, including the nuclei and cytoplasm of both cells. After germination, zeatin was accumulated in the plasmalemma or cell wall. ABA signal in the cytoplasm decreased; in the nuclei, it remained high. In growing tubes, the strongest zeatin and ABA signals were observed at the plasma membrane. The differences in ABA and cytokinin localization between species and dynamic changes in their level in spruce pollen highlight the key spatial and temporal parameters of hormonal regulation of gymnosperm pollen germination.

The present study reveals silica in sporoderms of micro- and megaspores of the modern quillwort Isoetes echinospora Durieu and homologizes layers of the sporoderm in spores of this plant. Here, the presence of silica in sporoderms of microspores has been documented for the first time, and observations of megaspore sporoderms were used to test various methods, such as energy dispersive (EDS) and electron energy loss (EELS) spectroscopies. The results elucidate the occurrence of silicon in the quillworts and will influence on the interpretation of their modern and fossil sporoderms.

New observations and an overview of the axillary hair structure in the groups of mosses sister to peristomate ones are provided. Three moss lineages, Takakiopsida, Sphagnopsida, and Andreaeobryopsida are characterized by mucilage release through the apical pore or otherwise apical structures. Axillary hairs of Andreaea however, differ from these lineages and are similar to all other mosses, where mucilage exudes through small temporary breakings along the entire cell wall of its upper cells. Fine structure of axillary hairs is illustrated for Sphagnum, Takakia, Andreaeobryum, and partly for Andreaea and Oedipodium, and general characteristics are given for most orders. A unique arrangement of axillary hairs is found in Sphagnum, where they occasionally appear not only in the leaf axils but also along the leaf base abaxially. Another rare feature of Sphagnum is that its axillary hairs are penetrable for fungi through the apical pore, which was previously known in mosses only for Takakia. A highly specialized structure regulating mucilage release in Takakia is described. Actin filaments and especially tubulin microtubules were found to be outstandingly abundant in axillary hairs of Physcomitrium but not in paraphyses, as seen in its GFP-labelled plants, and this feature may be common in other mosses.

Our aim was to unravel the underlying mechanisms of pollen wall development in Cymbalaria muralis. By determining the sequence of developing substructures with TEM, we intended to compare it with that of other taxa and clarify whether physical processes of self-assembly and phase separation were involved. In parallel, we tried to simulate in vitro the substructures observed in Cymbalaria muralis exine development, using colloidal mixtures, to determine whether purely physical self-assembly processes could replicate them. Exine ontogeny followed the main stages observed in many other species and was initiated by phase separation, resulting in heterogeneity of the homogeneous contents of the periplasmic space around the microspore which is filled with genome-determined substances. At every stage, phase separation and self-assembly come into force, gradually driving the substances through the sequence of mesophases: spherical micelles, columns of spherical micelles, cylindrical micelles arranged in a layer, laminate micelles. The final two of these mesophases define the structure of the columellate ectexine and lamellate endexine respectively. Structures obtained in vitro from colloidal mixtures simulated the developing exine structures. Striking columella-like surface of some abnormal tapetal cells and lamella-like structures in the anther medium confirm the conclusion that pattern generation is a feature of colloidal materials, after genomic control on material contents. Simulation experiments show the high pattern-generating capacity of colloidal interactions.

Seed morphology and ultrastructure of Lotus species from sections Dorycnium (L. dorycnium and L. graecus), Bonjeanea (L. rectus, L. hirsutusand L. strictus) and Lotus (L. corniculatus) have been studied using light and scanning electron microscopy. The seeds of studied species have a conservative structure typical for most Papilionoideae. Seed size, shape and color only partially allow distinguishing species in the studied group. The most morphologically distinguishable seeds are those of members of the polyphyletic section Bonjeanea, with L. rectus having the smallest and L. strictus the largest seeds. Seed size ranges in the species of the section Dorycnium overlap both between the members of the section and with seeds of L. hirsutus (section Bonjeanea). Seed surface ultrastructure around the hilum is very stable among studied species, whereas that on the lateral seed side is more variable. The types of surface sculpture on the lateral seed side do not strongly correlate with taxonomic position of species, but some correlations with eco-geographical patterns can be traced. The type of seed surface micromorphology with inconspicuous primary sculpture and thick secondary cuticular deposits was revealed in taxa, which distribution is connected with the Mediterranean region (L. hirsutus, L. dorycnium subsp. gracilis and partially L. rectus). Foveolate-papillose primary sculpture with thin secondary cuticular deposits is typical for species occurring in milder climate (L. corniculatus, L. strictus, L. graecus). Studied species can be subdivided into two groups by endosperm thickness. We believe that thin endosperm revealed in L. strictus and L. corniculatus may be a trait connected with the acceleration of development when spreading from the Mediterranean to the temperate climatic zone.

Sporoderm development in Andreaeobryum is studied and confirned to be similar to that in Andreaea in having no lamellate structure in the exine. The formation of the outer layers of the spore wall, external to the intine, proceeds by the accumulation of sporopollenin granules originating within the special wall of the sporocyte. Despite the outermost sublayer having a pattern similar to the perine in most mosses, and consequently was earlier reported as perine, it is mostly formed before the initial sporocyte walls disappear, thus questioning significant tapetal contribution. Therefore, we suggest to referring the outer sporoderm layer of Andreaeobryum to exine, whith has however is not originated by means of the tripartite lamellae, as in ferns, lycopods, hornworts, liverworts, and all other mosses excepting Andreaeobryopsida and Andreaeopsida.

Palynomorphological study of propolis and honey from the regions of the North Caucasus and the Lower Volga Russian Federation and Republic of Abkhazia (RA) has been held. Propolis samples have been obtained in Republic of North Ossetia-Alania (RNO-A), in Volgograd and Saratov regions of Russian Federation and RA at 2010 - 2015 years. Honey samples have been obtained in RNO-A and Republic of Ingushetia (RI) at 2015 year. Microscopy, determination of pollen types (PTs) and counting of pollen grains (PGs) carried out in 3-fold repetition on temporary preparations with a cover glass area of 24 x 24 mm under a light microscope. An analysis of the palynological spectra of propolis and honey samples showed the dominance of pollen from plants of the Asteraceae family. Propolis always contained pollen from several PT, a third of the samples of honey were monofloral. An analysis of the occurrence of PT was carried out. All propolis samples aligned according to the degree of contamination. Samples of honey can differ greatly in the wind-pollinated component.