Vol 109, No 5 (2024)

Similarities and differences between Monanthes anagensis and M. muralis were revealed as a result of the study of their anther development and structure. The similarities: 4-locular isobilateral (on transverse section) anther with a 4-rayed connective; it does not fuse with the filament in the basal part, and the connective is visible only in the middle part; and in the upper and lower parts of the anther, the microsporangia of each theca are fused with their lateral surfaces; the microsporangium wall on the distal side is formed according to the centrifugal type; simultaneous microsporogenesis, tetrahedral tetrads of microspores, 2-celled pollen grains; tannins accumulate in the epidermal cells on the distal side of the microsporangium wall; parietal tapetum (amoeboid tapetum as a variation). Differences: length of anther zones; initial stages of microsporangium formation; the structure of the formed microsporangium wall: four (M. anagensis) or five (M. muralis) layers of cells, with the species differing in the number of middle layers; the process of specialization of endothecium cells, namely in M. muralis the cells increase in radial direction after the stage of prophase I of meiosis, while in M. anagensis after the stage of microspore tetrads; destruction of cell walls in the tapetum occurs at the stage of microspore tetrads in M. anagensis, and of single microspores in M. muralis.

Based on the complex of characteristics of the anther structure and development, the studied species of the genus Monanthes show the greatest similarity with members of the genera Aeonium and Sedum. The data obtained are not in conflict with cladistic constructs. The studied species Aeonium balsamiferum and A. ciliatum, as well as Monanthes anagensis and M. muralis belong to the same Aeonium clade, taking an intermediate position between the Telephium (Sedum kamtschaticum) and Acre (S. palmeri) clades.

The purpose of this report is to reveal features of structural organization of 12 species of trees of the temperate zone, which constitute the first layer of phytocenoses, from the standpoint of the concept of C. Edelin (1991). The structural organization of the studied species is based on the principle of hierarchic construction of the crown, i.e. the subordination of lateral skeletal axes to the main axis, the trunk. In flowering plants, sympodial growth is widespread, in one of its variants there are prerequisites for the appearance of elements of polyarchic organization in the crown – two equivalent axes forming a fork, which sometimes leads to a bifurcation of the trunk. Subsequent differentiation of the fork axes into the leading and subordinate can lead to the formation of branches that exceed the branches of the hierarchic organization in terms of durability and power. The appearance of elements of a polyarchic organization is less determinate than of the elements of a hierarchic one. Among the studied species, the forks appear less often in Picea abies, and more often in Salix alba and S. pentandra. In shade-tolerant species under low light conditions, the inclusion of elements of a polyarchic organization in a hierarchic structure underlies the formation of an umbellate crown, and in open space in all species, except Picea abies, it allows forming more spreading crown. No correlation was revealed between the structural organization of the studied species and their role in the successional system, as well as between their longevity and shade resistance.

The data on new records of Chrysococcus furcatus vegetative cells and stomatocysts obtained using scanning electron microscopy (SEM) are presented. The species has been recorded for the first time in the Urals; three habitats were discovered during extensive multiyear sampling. The originality of the research lies in the study of the environmental conditions of cell growth and mass formation of stomatocysts in natural waterbodies, as well as in obtaining information on the increase in silicon content in mature stomatocysts using energy-dispersive X-ray spectroscopy. In the Southern Ural population, the morphotypes of stomatocysts with an obconical long collar of varying length are found. Some specimens had a single needle-like spine bifurcating when mature, located on or very close to the posterior pole. A new form with multiple needle-like spines located on the posterior pole of stomatocyst has been discovered. The rest of the cyst body was ornamented with conical scabrae. Descriptions are illustrated with electron micrographs. The obtained results supplement the information on the algal flora of Russia and can be used in environmental monitoring of waterbodies and paleoreconstructions.

The article provides data on two plant species and one hybrid, all from the family Lamiaceae, new to the flora of Sakhalin Island, collected by us in 2023: Melissa officinalis L., Mentha × piperita L. and Origanum vulgare L. The revealed species are ergasiophygophytes and colonophytes. Melissa officinalis and O. vulgare are also new genera to the flora of the island.