Botanicheskii Zhurnal

Trimonoecious plant populations consist of individuals that have staminate, pistillate, and perfect flowers. Trimonoecy is very rare in angiosperms, and knowledge about it is extremely sparse. Based on literature data and personal research, a list of trimonoecious plants in the world flora has been compiled, which includes 73 species from 44 genera belonging to 29 families and 19 orders of angiosperms. Trimonoecy occurs in 6.9% of families, 0.3% of genera, and 0.025% of species in angiosperms. Trimonoecious species have not been identified in the group of basal angiosperms and magnoliids. The highest proportion of trimonoecious species occurs within the monocots: 20.0% of families, 0.7% of genera, and 0.05% of species, while the vast majority of trimonoecious plants (80.3% of all species) are found among the Superrosids (27 species) and Superasterids (32 species). Five families are particularly noted for having trimonoecious species: Apiaceae (16 species from 2 genera), Amaranthaceae (7 species from 3 genera), Cleomaceae (6 species from 2 genera), Commelinaceae (5 species from 1 genus), and Poaceae (4 species from 4 genera). Slightly less than half of all trimonoecious species belong to five genera: Heracleum L. (13 species), Aneilema R.Br. (5), Cleome L. (5), Amaranthus L. (4), and Lomatium Raf. (3). The relationship and possible correlation of trimonoecy with such biological and ecological characteristics as life form, mode of pollination, perianth color, pericarp consistency, presence of related monoecious taxa, geographical latitude of occurrence, and distribution along floristic phytochorions has been analyzed and is presented herein. The article ultimately discusses the dimensional differences in the perianths of the three flower types, pollen fertility and pollen productivity of perfect and staminate flowers, the location and ratio of perfect, staminate, and pistillate flowers on individuals, as well as the mechanisms of the origin and evolution of trimonoecy in angiosperms.

The study of materials from littoral biotopes of Nalychevo Lake (“Nalychevo” Natural Park, Eastern Kamchatka) using scanning electronic microscopy revealed 164 taxa of diatoms from 57 genera, including new ones to the flora of Russia: Cocconeis pseudothumensis, Cymbopleura acutiformis, Encyonema subminutum, Gomphonema cf. khienticense, and Witkowskia parvapolonica. 15 algae have been identified to the genus only, namely Achnanthidium, Amphora, Caloneis, Cocconeis, Encyonema, Fragilaria, Gomphonema, Navicula, Pinnularia, Placoneis, Planothidium, Sellaphora. The obtained data have significantly expanded taxonomic spectrum of Bacillariophyta in the lake: from 35 to 189 species and varieties, and from 18 to 58 genera. The most taxonomically diverse are the genera Achnanthidium (8 taxa), Navicula (13) and Gomphonema (16). Ecological analysis of the flora of Bacillariophyta from biotopes with agglomerations of Aegagropila colonies of various ages has shown that the vast majority of discovered algae prefer fresh, subalkaline water bodies. According to saprobity index, the surveyed littoral areas of the lake are classified as oligosaprobic with elements of mesosaprobity.

The article presents the diversity of riparian-aquatic communities in the north-western part of Ladoga within the Leningrad Region: 5 groups of associations (Phragmiteta australis, Equiseteta fluviatilis, Glycerieta maximae, Cariceta acutae, Comareta palustris), 14 associations and 5 variants of associations. Four associations (ass. Phragmitetum australis–Glycerietum maximae, ass. Caricetum acutae–Glycerietum maximae, ass. Comaretum palustris–Caricetum cespitosae, ass. Comaretum palustris–Caricetum lasiocarpae) were not previously reported for the skerry region of Ladoga Lake, but were described for other regions of the European part of Russia. Mapping of the riparian-aquatic vegetation was carried out, verification using high-resolution images and field verification of the selected contours allowed reliable deciphering the communities Aquiherbosa, Equiseteta fluviatilis and Phragmiteta australis.

In course of field work in the Okinsky District of Buryatia (July 2023), an expedition team from Moscow State University and Main Botanical Garden of the Russian Academy of Sciences discovered and initially examined rare old-growth sparse spruce forests with moss-lichen (Rhytidium rugosum – Cladonia spp.) bottom layer on lavas in the Zhom-Bolok River valley (Oka Plateau, East Sayan). In July 2024, the 2^nd expedition revisited and explored the forests in the area in more detail. The paper provides the first collected data on these unique communities (including a complete relevé of one of them). The differences between these communities and lichen/moss-lichen spruce forests from other regions of Russia are discussed in details. The plan to investigate these forest communities and to elaborate measures for their protection is envisaged. The spruce moss-lichen woodlands of the Oka Plateau meet both the IUCN Red List of Ecosystems and the Russian regional criteria for rare and endangered ecosystems.