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The main objective of this research was to conduct a comparative pollen morphological analysis of some representatives of the genus Cuscuta in relation to taxonomy. Investigations of 38 species and 1 variation revealed that not only the number, but the colpi length, as well as the exine ornamentation (at the SEM level), can be regarded as a diagnostic feature. For all the taxa studied, the common zonocolpate type of pollen was observed, represented by three variations: I) colpi long; II) colpi of medium length; III) colpi short. In combination with colpi length, variations in the number of colpi were also identified, such as: I) 3(4)-zonocolpate pollen grains with long colpi (in most of the species studied from subgenera Grammica and Cuscuta , as well as in C. monogyna from the subgenus Monogynella ); II) 4(3)-zonocolpate pollen grains, with long colpi ( C. cristata from subgenus Grammica ); III) 3-zonocolpate pollen grains both with long colpi and colpi of medium length ( C. abyssinic a from subgenus Cuscuta and C. africana , C. angulata from subgenus Pachystigma ); IV) 3-zonocolpate pollen grains with colpi of medium length were noted for species from all four subgenera ( C. cassytoides , C. lupuliformis from subgenus Monogynella , C. kotschyana from subgenus Cuscuta , C. nitida from subgenus Pachystigma and C. jalapensis , C. rostrata , C. suaveolens from subgenus Grammica ); V) 3–4- or 4-zonocolpate, with short colpi ( C. lehmanniana and C. gigantea from subgenus Monogynella respectively); VI) 5–6-zonocolpate, with short colpi ( C. reflexa from subgenus Monogynella ). Using SEM, three main types of exine ornamentation were also identified: perforate, foveolate and reticulate. The last type in the vast majority of the cases was presented in combination with echinae (rarely with spines or granules). The data revealed that the presence of the significant similarity of palyno-morphological characteristics in representatives of the subgenera Cuscuta , Pachystigma and Grammica , with the exception of the species Lepidanche adpressa (syn. C. compacta ), makes it difficult to create an identification key at the level of individual subgenera. Pollen features can be most clearly used only to distinguish the subgenus Monoginella , reflecting its certain isolation within the entire Cuscuta genus. The presence of a highly specialized reticulate exine ornamentation in Lepidanche adpressa (syn. C. compacta ), not identified for the pollen of any of the studied taxa of the subgenus Grammica , indicates a significant proximity of this species to the subgenus Monogynella . For the species C. reflexa , the obtained palyno-morphological data are consistent with the previous opinion about the separation of this species, as well as its more advanced position within the genus Cuscuta .

Crocus L. (Iridaceae) is systematically a very problematic genus due to the lack of clear distinctive features, wide range of habitats and the heterogeneity of morphological features. This genus is also highly heterogeneous from a karyological point of view. Apart from the most common spiraperturate pollen grains in Crocus, the authors frequently mentioned a number of other aperture types for individual species (subspecies, variations, etc.), i.e. polyrugoidate, nonaperturate (inaperturate), polyaperturate, with more or less extensive furrows, with short furrows, etc. The purpose of this work is to perform a palyno-morphological analysis of pollen aperture types noted in the genus Crocus. The reason for the study is a significant disagreement among researchers when describing the types of pollen apertures in the genus Crocus. An analysis of the literature, as well as the results of our previous studies, showed that the genus Crocus is characterized by inaperturate (nonaperturate), polyaperturoidate, spiraperturate and net-like pollen apertures. The similar net-like apertures were observed for some representatives of the subgenus Scorpiris Sach of the genus Iris L., in particular, in Iris atropatana Grossh. In our opinion, this aperture type can serve as a link between the genus Crocus and the subgenus Scorpiris of the genus Iris. We suggest, that the spiraperturate pollen type mentioned most often for the representatives of the genus Crocus can be considered the basic type within the genus. On the other hand, formless aperture-like areas are genetically unstable transitory variations, which occurred arbitrarily due to mutations. Finally, “polyrugoidate” (or with net-like apertures) pollen type noted in the literature for C. chrysanthus subsp. punctatus F.Candan et N.Özhatay may be considered to be more advanced in the genus Crocus

The article presents the results of a comparative palyno-morphological analysis of the representatives of the Salsoloideae subfamily (Chenopodiaceae) in South Transcaucasia. Out of 25 species belonging to 13 genera of Salsoloideae subfamily in South Transcaucasia, pollen morphology of 23 species from 12 genera was investigated, as well as an analysis of the pollen characteristics was conducted. Data on five key features of pollen (on LM level) were statistically analyzed including pollen diameter, pore number, pore diameter, exine thickness, and mesoporium width. The results indicated that within the Salsoloideae subfamily of South Transcaucasian flora the first three features may be considered diagnostic. The application of a scanning electron microscope (SEM) has revealed the fourth diagnostic feature of the pollen within the Salsoloideae subfamily, specifically, the number of spinules on the unit surface of the pollen, which enables, in several cases, to conduct intergeneric or interspecific differentiation. Based on the obtained data, typification of pollen within the Salsoloideae subfamily of South Transcaucasia was carried out for the first time. As a result, two morphological types and four subtypes combined in two palynogroups were distinguished. The subdivision into palynogroups is based on differences in the size of pollen grains. Only species Climacoptera crassa with pollen of average sizes (26–33/29 μm in diameter) is included into the monotypic Palynogroup I, all other investigated species with small pollen grains (10–25 (27)/22 μm in diameter) are joined in Palynogroup II. Allocation of species into two different Types of Palynogroup II is based on the presence of a significant difference in the size of small pollen grains of individual species. In particular, species with relatively large pollen grains (> 20 μm in diameter) are included in Type 1, while species with relatively small ones (≤ 20 μm in diameter) are joined in Type 2. And finally, the distribution of species into the subtypes and variations of Palynogroup II is based on differences in pore number and size. The identified key palyno-morphological features made it possible in some cases to specify the taxonomic boundaries, as well as the relationship between taxa within the subfamily Salsoloideae.