Botanicheskii Zhurnal

Western Siberia is a fire-hazardous territory of Russia due to a wide distribution of mires including drained ones. Investigation of processes of the vegetation cover restoration after fires is the target of current interest. This paper provides an assessment of qualitative and quantitative parameters of post-fire restoration of the plant cover in the 6th–9th year of succession in ombrotrophic bogs of taiga and forest-tundra in Western Siberia: the species composition, coverage and aboveground biomass of various plant components.The study was carried out in three mire massifs. Two mires (Bakchar and Ust-Bakchar) are oligotrophic Sphagnum-dominated bogs located in the southern taiga subzone within the Tomsk Region. The third mire (Pangody) is a lichen-dominated palsa complex with Sphagnum hollows located in the forest-tundra in the Yamalo-Nenets Autonomous Region. The bogs in the southern taiga were drained in the 1980s, and as a result, vegetation and soil properties have transformed in Ust-Bakchar mire but not in Bakchar mire. Five pyrogenic sites in Bakchar mire and two sites in each of the the other two bogs were selected for the study. An undisturbed control site was chosen in each bog as well. The species composition, coverage and the stock of aboveground biomass were studied. The biomass was evaluated by mowing in certain plots.We found out that after 6–9 years of succession, the species diversity of vascular plants has increased and that of mosses and lichens has decreased in pyrogenic sites in comparison with undisturbed ones. The exceptions were the hollows in forest-tundra where the diversity of Sphagnum mosses has increased. Vegetation was recovered due to typical bog species. When the peat deposit burned almost down to the mineral bed, the highest diversity of vascular plants and the appearance of the species not typical of the palsa were observed. Restoration of the moss carpet occurred due to the colonization of peat by species of the genera Polytrichum and Sphagnum in subequal shares. The hollows in the forest-tundra were the exception. There, Sphagnum mosses prevailed and Warnstorfia fluitans also settled. Within one bog, the restoration of the plant cover occurred unevenly due to the pyrogenic transformation of the microrelief and the appearance of habitats with different soil moisture conditions. The coverage and phytomass of the herb-subshrub layer were restored most quickly. Moss colonization was slower, and lichen colonization was minimal. Therefore, on the palsa in the forest-tundra, the total stock of living phytomass was five times lower than in the control undisturbed sites. The total plant stock in other bogs was close to that on the control undisturbed sites or lower no more than twice.

Gynodioecy in the herbaceous polycarpic plant, Lomelosia songarica, from Tajikistan was identified and is described here for the first time. Three populations were studied in 2022. The plants produce flowers of two types, bisexual and pistillate, occurring on individuals of three different variants: hermaphrodite (bisexual flowers only), female (pistillate flowers only), and gynomonoecious (bisexual and pistillate flowers). The marginal flowers in floral units are irregular (transversely zygomorphic), the median ones are almost regular (actinomorphic). Two types of bisexual flowers have been identified, differing in the degree of androecium development: 1) all four stamens are fertile and produce viable pollen; 2) partially androsterile, i.e., one, two, or three stamens are sterile due to incompletely developed pollen, in this case the anthers remain closed. In pistillate flowers, rudiments of the androecium are preserved, represented by staminodes which produce no pollen. Bisexual flowers are larger than pistillate ones by most of the studied parameters. There are two types of L. songarica populations: monomorphic (consisting only of hermaphrodite individuals) and heteromorphic (gynodioecious). In the gynodioecious population, the frequency of hermaphrodite, female and gynomonoecious individuals was subequal (33.3%). The article addresses the adaptive significance of the gynomonoecious individuals of this species serving as an alternative to strictly female individuals in light of the presence of exclusively cross-pollination due to strict intra- and interfloral protandry and synchronicity of flowering of the floral units within synflorescences.

The first record of the green alga Capsosiphon fulvescens for the Leningrad Region and the Russian waters of the Gulf of Finland is reported. Description, illustrations of the morphology and anatomy of this species are provided; its distribution and growth conditions are discussed. The appearance of this pollution-resistant species may be an indicator of increased water eutrophication.

The information is given on 3 species of the genus Acer L. new to the flora of Sakhalin Island: A. pseudoplatanus L., A. saccharinum L., A. tataricum L. The localities of the newly found species are listed, brief data on their geographical distribution and growing conditions are presented.