Vol 108, No 4 (2023)

Based on geobotanical studies conducted in the summer of 1989 in the western part of the Chukchi Highlands, it was found that the number of moss species varies depending on the altitude, slope exposure and angle. Taking into account samples of different volumes for different parameters, the following dependencies were revealed: the largest number of species (35) was noted in the altutude range of 250–300 m, the smallest (14) – for the altutudes above 400 m; the slopes of the northern exposure are characterized by the largest number of species (22), the south-eastern and north-western ones – by the smallest number (18); a decreasing tendency in the number of species manifests itself with an increase in the slope angle: on gentle slopes (up to 5°) there are 37 species, while on steep ones (more than 25°) their number decreases to 23. Based on the position of the species optimum on the scale of soil moisture, 7 groups of species were distinguished: xerotopes, mesoxerotopes, xeromesotopes, mesotopes, hygromesotopes, mesohygrotopes, hygrotopes. The total percent cover value of mosses varies differently on the slopes of different exposures (on gravelly-fine-stony substrates): on the northern slopes it increases to an altitude of 400 m, then decreases sharply; on the south-western slopes it only increases to an altitude of 450 m, on all the other slopes it monotonously decreases from an altitude of 230–250 m to 370–600 m. At different altitude levels, the maximum of the total percent cover value of mosses is also related to the slope exposure: in the lower altitude range, it is confined to the south-eastern slopes, in the medium altitudes, it shifts to the north-eastern slopes, and in the uppermost range to the south-western ones. With an increase in the slope steepness, the total percent cover value of mosses decreases on the slopes of all exposures, with the greatest intensity being on the eastern slopes.

The structure of needle mesophyll and the forms of assimilative cells in the genus Larix species are discussed on the example of L. gmelini var. gmelini, L. decidua, L. kaempferi and L. sibirica. Needle samples were fixed in the Gammalund’s mixture. The study of the mesophyll was carried out on transverse, paradermal and radial sections of the middle part of the needles using a light microscope. To clarify the shape of chlorenchyma cells, macerated preparations were used. It is shown that the needle mesophyll in Larix species mainly consists of large cells of complex shape, which touch their convex parts or ends to form a well-developed system of intercellular spaces, which may comtribute to intense gas exchange. Different variants of flat folded, flat cellular and more complicated folded-cellular assimilative cells are described. The flat folded cells are characterized by a variety of lobed configurations on transverse sections and elongated oval projections on radial sections. The flat cellular cells are found on needle longitudinal sections of and consist of cellular links facing both perpendicular (cellular cells of the first group) and parallel (cellular cells of the second group) to the leaf surface. The folded-cellular cells combine transverse folded contours and longitudinal cellular outlines. In the needle mesophyll of the studied Larix species, weak differentiation into palisade and spongy parenchyma is observed; the cells of the middle part (median cells) are additionally distinguished between them. The palisade tissue is formed mainly by cellular cells of the first group, the spongy tissue by cellular cells of the second group. The median cells are located on both sides of the vascular bundle along a large needle radius; they can be either flat and slightly folded, or folded-cellular. The studied Larix species are similar in th esize of assimilative cells and the structure of the needle mesophyll; the main differences between them are related to the features of cell dissection both in transverse and longitudinal directions.

The genus Mesenteriophyllum, described by T.A. Sistel in Kyrgyzstan and known in Australia and Antarctica, is revealed on the Taimyr Peninsula. The new species Mesenteriophyllum sixtelae with a transversely wavy thallus is described there. Morphologically similar plants were found in Central Siberia. The genus Kotchumdeckia is distinguished there, differing from Mesenteriophyllum by a flat thallus and a broad flattened marginal border. The newly described species Mesenteriophyllum sixtelae, Kotchumdeckia borutchinkinae, K. clavata, and K. parallela differ in the shape of the thallus. These plants belong to Phaeophyta. There are some Phaeophyta thalli overgrown with Cyanobionta.

New data on distribution of 8 vascular plant species in Northern Koryakia (mainland part of Kamchatka Territory) is presented. Five native species (Bryanthus gmelinii D. Don, Cassiope lycopodioides (Pall.) D. Don, Listera cordata (L.) R. Br., Lonicera chamissoi Bunge ex P. Kir., Saxifraga tolmiei Torr. et Gray) and 3 alien species (Galium mollugo L., Leucanthemum vulgare Lam., Linaria vulgaris Mill.) are new to the mainland of the Kamchatka Territory.

The discovery of Viola reischenbachiana Jord. ex Boreau in the Kaluga Region is reported. The species is for the first time reliably indicated for the Central Russia. Its morphological differences are discussed. The occurrence in isolation from the main area is apparently due to the drift during the deployment of German troops on the territory of the Kaluga Region.

Wall charts and posters depicting plant structure and evolutionary relationships as phylogenetic trees have been important teaching tools for many decades. With the development of digital technologies, new approaches to the traditional concept have become possible. The article briefly discusses the history, development and significance of the “Plant Phylogeny Posters” project. This project is a joint work of a growing team of more than 200 specialists from more than 50 nations from all around the world. The portfolio currently consists of nearly 600 posters in 54 poster titles and in 45 languages (as of early 2023). All posters are freely available on the Internet and are regularly updated.

Information about the All-Russian scientific seminar devoted to the age structure of plant populations and the analysis of ontogenetic spectra is provided. The seminar was held on February 20, 2023 in Moscow. More than 50 people from 17 educational and scientific institutions took part in the seminar.