Bidens Frondosa Research Articles

Modelling rice competition with Leptochloa fusca, Bidens frondosa and Ammannia coccinea in transplanted rice cultivation

AbstractA 2‐year field experiment was conducted in Daejeon, South Korea, to investigate changes in the growth parameters of rice plants during the growth and model the rice yield loss as affected by the competition with Leptochloa fusca, Bidens frondosa and Ammannia coccinea under transplanted rice cultivation. Compared with B. frondosa and A. coccinea, L. fusca significantly reduced the number of tillers at the early growth stage, resulting in more reduction in the number of panicles and other yield components such as the number of spikelets, ripened grain ratio and the ultimate rice yield at the later growth stage. Among the components, the panicle number was the most negatively and positively correlated with weed density and rice yield, respectively. Cousens' rectangular hyperbola model predicted that weed competitiveness value represented by parameter β was 0.0337 and 0.0572 for L. fusca, 0.0124 and 0.0165 for B. frondosa and 0.0059 to 0.0061 for A. coccinea in 20.8 and 15.2 hill m−2 rice densities, respectively, indicating the competition effect of L. fusca on rice yield was greater than that of B. frondosa and A. coccinea. Weed densities corresponding to a 50% reduction in the rice yield were 27 and 18 for L. fusca, 81 and 61 for B. frondosa and 169–164 for A. coccinea in 20.8 and 15.2 hill m−2 rice densities, respectively. Weeds are more competitive in low‐density rice plots, leading to greater yield loss. In addition, the economic thresholds (ET) are positively correlated with rice densities and negatively correlated with weed competitiveness. Although low‐density rice transplanting may offer economic benefits during cultivation, optimal rice density and weed control strategies are important for securing a high yield. Therefore, the model and findings could be applied to decision‐making systems in rice farming where weed interference is present.

Адвентивный компонент банка семян некоторых лесных сообществ островов реки Волги

The paper presents the results of studying the adventive component of the seed bank of the Oak Mane Island of the Volga River Valley in the vicinity of the city of Saratov. Seeds of 12 species of adventitious plants were registered in the seed bank of the studied forest communities. All identified seeds belong to plant species belonging to one department of Magnoliophyta, 8 families and 12 genera. The Asteraceae family plays a leading role in the taxonomic spectrum of adventitious seed bank species (42%). Mesophytic mesotrophic (63.6%) heliophytic grouping of plants dominates in relation to ecological regimes. Mostly there are species of North American origin (60%). Herbaceous annuals (33% of species) and trees (34%) play a significant role. A significant impact on the composition of seed banks was caused by the unintentional entry of seeds of plants that are “refugees from culture” into this territory. Most adventitious plants, represented by both vegetating individuals and seeds, have penetrated into natural cenoses, and in some cases even partially transformed their structure, which is due to their reproductive potential and ability to compete with representatives of the native flora of natural habitats. In the studied area, foci of the concentration of seeds of drift plants in different communities were revealed, in continuous placement (Acer negundo, Bidens frondosa and Populus alba), disjunctive (Fraxinus pennsylvanica, Parthenocissus quinquefolia, Echinocystis lobáta, Impatiens glandulifera), sporadic – Ambrosia trifida, Artemisia sieversiana, Crataegus sanguinea, Inula caspica and Ulmus pumila. An increase in the number of adventitious species presented in the seed bank was recorded, but the number of seeds decreased.

Comparative study of morphological and anatomical features of Bidens L. Species

Introduction. Determining closely related impure species when confirming the authenticity of medicinal plant raw materials (mprms) is a very difficult and controversial task, especially for crushed and powdered mprms. One of such objects is the three-part beggarticks, which is prone to polymorphism and occupies the same area with the nodding beggarticks, the Spanish needles and the devil's beggarticks. Objective: to conduct a comparative pharmacognostic analysis of species of the genus Bidens L., which can be collected together with the pharmacopoeial species – three-part beggarticks. Material and methods. The objects of study were dried herbs of three-part beggarticks (Bidens tripartita L.), nodding beggarticks (Bidens cernua L.), Spanish needles (Bidens bipinnata L.), and devil's beggarticks (Bidens frondosa L.), collected in the Moscow region in 2020–2021. In this work, we studied the anatomical and morphological structure of leaves, as the most preferred part from a diagnostic point of view. The study of anatomical and morphological characteristics was carried out in accordance with the General Pharmacopoeial Monograph of the Russian Federation State Pharmacopoeia XIV 1.5.1.0003.15 “Leaves”. Results. A comparative description of the anatomical-diagnostic external and microscopic characteristics of the Bidens leaves has been obtained. Bidens tripartita and Bidens frondosa are higher than others. In contrast to the impure species, the Bidens tripartita has the largest deeply trifid, irregular serrated leaves, more pronounced tortuosity of the epidermal cells of the upper side of the leaf, multicellular thin-walled caterpillar-like and simple thick-walled hairs are combined, and the secretory canals in the mesophyll located along the vein. Conclusion. Among the studied Bidens species, each has characteristic features of its morphological and anatomical structure. These specific features can be used to establish the authenticity of the mprms and distinguish it from impure Bidens species, which require further research.

Arbuscular mycorrhiza increases the facilitation between adult plant and seedling but root‐knot nematode inhibits it

AbstractSoil biotic and abiotic factors can affect the interaction between invasive and native species. However, it is not yet clear how arbuscular mycorrhizal (AM) symbiosis affects the interaction between adult invasive plants and neighboring seedlings. We used an invasive weed (Bidens frondosa) to test the hypothesis that adult invasive plants facilitate the growth of neighboring seedlings through AM symbiosis, and this facilitation can be inhibited by the biological stress of root‐knot nematode infection. The results showed that the height and total biomass of seedlings near the adult plant increased, indicating that the belowground effects mediated by AM symbiosis played a facilitative role. The positive growth response to resource allocation between adult plant and neighboring seedlings through mycorrhizal connection was inhibited when adult plants were infected by root‐knot nematode. Only the total biomass and root–shoot ratio of adult plants were increased, while seedling growth performance did not change. Our results supported the hypothesis that adult invasive plants can facilitate their neighboring seedlings growth through AM symbiosis and the benefits vary with biotic stress on adult plant. These findings provided important evidence to explain the role of AM symbiosis in plant invasion.

Phytotoxic and Cytotoxic Effects, Antioxidant Potentials, and Phytochemical Constituents of Stevia rebaudiana Leaves.

Stevia (Stevia rebaudiana), recognized for its low-calorie, sugar-free attributes, and various health benefits, has potential applications beyond human consumption, particularly in agriculture. This study explored the potential uses of Stevia in both agricultural and healthcare contexts by examining its plant-inhibitory, cytotoxic, and antioxidant effects. The methanolic extract of Stevia leaves was fractionated into hexane, ethyl acetate, chloroform, and water fractions. These fractions were then subjected to the bioassay analyses above and underwent identification of their chemical constituents. The results indicated that the ethyl acetate fraction demonstrated significant inhibitory effects on weed germination and growth of Beggars tick (Bidens frondosa) (100% inhibition at 1000 ppm of dose). This fraction also exhibited the highest antioxidant activity, total phenolic, and total flavonoid contents (IC50 DPPH = 18.67 μg/mL, 103.50 mg GAE/g fraction, and 410.16 mg QE/g fraction, respectively). In contrast, the chloroform fraction showed the highest cytotoxic effect (LC50 = 700.01 ppm) in the brine shrimp (Artemia salina) mortality evaluation. Pearson's correlation analysis revealed a positive correlation among plant inhibitory effects, antioxidant potentials, and phenolic/flavonoid contents of Stevia. FTIR spectra confirmed the presence of phenols and nonpolar components in the ethyl acetate and chloroform fractions. In addition, GC-MS analysis successfully identified Stevia's key constituents, including tetracontane, hexadecane, hexadecanoic acid, methyl ester in the ethyl acetate fraction, and spiro [4.5] decan-7-one and 6-hydroxy-4,4,7a-trimethyl-5,6,7,7a-tetrahydrobenzofuran-2(4H)-one in the chloroform fraction. This study underscores the potential of S. rebaudiana as a source of natural antioxidants and herbicides, offering valuable insights into its diverse applications in agriculture.

First report of cucumber mosaic virus infecting Bidens frondosa (devil’s beggarticks) in Korea

First report of cucumber mosaic virus infecting Bidens frondosa (devil’s beggarticks) in Korea

Моніторингові обстеження флори ділянки русла річки Турія в м. Ковель по вулиці Сагайдачного

In 2021, the project of reconstruction of the Turia riverbed in the area of Sahaidachnoy Street in the city of Kovel, Volyn Region, in the area of the bridge crossing, was launched. In order to timely identify, prevent and eliminate the negative consequences of the impact of planned activities on the phytodiversity of the Turia River, post-project monitoring was carried out every quarter, which allowed to objectively assess the impact of the performed works on the plant cover. Studies have shown the recovery of typical aquatic and coastal aquatic vegetation in the area of activity. Among aquatic plants Nuphar lutea (L.) Smith., Myriophyllum spicatum L., Potamogeton crispus L., Lemna minor L. Species Salvinia natans(L.) All are typical. recovered on the territory of the planned activity in shallow backwaters near the banks of the river with a projective coverage of 20-40%. Above and below the research site, the species shows high phytocenotic activity with a projective cover of 40-100%. Of the coastal water plants, typical are Butomus umbellatus L., Lycopus europaeus L., Glyceria maxima (C.Hartm.) Holmb, Lythrum salicaria L., Typha latifolia L., Rumexhydrolapathum Huds., Ranunculus sceleratus L., Myosotis scorpioides L, Mentha aquatica L., Bidens frondosa L., Iris pseudacorus L. The groups of Salvinieta natantis formation, Salvinietum natantis purum and Salvinietum (natantis) lemnosum (minoris) associations included in the Green Book of Ukraine were revealed; Nuphareta luteae formation group Nupharetum (luteae) salviniosum (natantis) association. The work carried out on the improvement of the banks of the Turia River had a positive effect on the spread of weeds, a lawn was created, and highly decorative cultivars of maple and willow were planted as solitaires.
 The study of the territory of the Turia River above and below the planned activity proved the dominance of ruderal biotopes of perennial grasses with the dominance of anthropophytes, among which there are species with high phytocenotic activity. Their presence may have threatening consequences for the existence of the already reconstructed part of the Turia River bed. Among them, species dangerous to human health: Heracleum sosnowski Manden. and Ambrosia artemisiifolia L.

New findings of adventive plants in the Tomsk Region

The article contains new data on localities of new and rare adventive plants in the Tomsk Region. Hypochaeris radicata L. is not only a new species but a representative of a new genus for the flora of Siberia; Geranium pusillum L. is reported here for the first time for the Tomsk Region and constitutes the first record within the forest zone of Siberia; for 4 rare adventive species (Bidens frondosa L., Impatiens parviflora DC., Cynoglossum officinale L., Hesperis pycnotricha Borbás et Degen), new localities were noted, indicating their further distribution in the southern regions of the Tomsk Region and extending the distribution range of the species.

Findings of new and rare species of vascular plants in mires of the Urals and the Trans-Urals

The materials of the article contain data on the findings of 30 species of vascular plants from the territory of the Urals and the Trans-Urals. Among them, there are two new species for this territory, one for the Sverdlovsk Region – Phragmites altissimus, and one for the Kurgan Region – Rhinanthus songaricus. The second finding of the alien species Bidens frondosa for the Kurgan Region is reported. An information about the new locality of Liparis loeselii, which is included in the Red Data Book of the Russian Federation, is presented as well, along with the data about the findings of 26 other rare species of vascular plants in the mires of the South Ural region, listed in the Red Data Books of the region. The article makes important additions to the knowledge of the distribution of protected vascular plant species in the study region.

Morphological and Micromorphological Investigations of Bidens frondosa L. from Flora of Krasnodar Region, Russia

Complex morphological and micromorphological studies have been made about bootjack bur (Bidens frondosa) growing on the territory of the Krasnodar region. The lamina is of dorsoventral type. The conduction system has fasciations, three closed collateral bundles, are present near the vein. The leaf is of amphistomatic type, stomatic apparats are present in a small amount. Anticlinical walls of the main cells of the epidermis are strongly flexuose. The lower epidermis if compared to the upper one has a large number of stomatic apparatus of anisocytic type. The trichomes are leggy, represented by multicellular hairs of different shapes and lengths. Micromorphological capabilities of bootjack bur’s transverse section of the caulis and leafstalk have been studied. Received micromorphological data is a fragment of complex pharmacognostic studies of the Bidens kind. For acquiring the anti-allergic medication in the future, it is necessary to make pharma-technological studies and come up with the necessary medical form in the shape of thick extract and also make pharmacological studies in acquiring this medical form.

Impact of European Beaver (Castor fiber L.) on Vegetation Diversity in Protected Area River Valleys

The aim of the study was to evaluate the impact of European beaver (Castor fiber L.) on vegetation diversity and the expansion of non-native plant species in areas surrounding watercourses in Polesie National Park, Poland. The investigation was carried out within six watercourses inhabited by beavers and four comparison watercourses where beaver were absent. European beaver living in the park had a small excursion range, reaching a maximum distance of 25 m from the watercourse so that effects on vegetation diversity were limited to the immediate vicinity of the watercourse. Beaver significantly influenced diversity of the tall tree and forest floor vegetation, while it did not significantly modify the diversity of the low tree and shrub layer. Five alien plant species were documented. The alien species most strongly associated with beaver activity was devil’s beggartick (Bidens frondosa L.), which occurred in the immediate vicinity of beaver dams. Other alien species most benefiting from the presence of beaver were giant goldenrod (Solidago gigantea Aiton) and black cherry (Prunus serotina Ehrh.). Our study confirmed hypotheses found in literature according to which beaver activities that reduce the proportion of native species can promote the expansion of plant alien species.

Флора водоемов и водотоков Саратовской области: история изучения и современное состояние

Water plants and coastal riparian plants are an integral part of the habitat forming component of water ecosystems in Saratov region. This article gives a review of long-term research of flora in many water reservoirs and water streams of the Saratov region. The analysis of literature in its historical aspect showed that the degree of scientific knowledge about water flora in the Saratov region is still insufficient despite multiple research projects conducted at the end of the 20th and beginning of the 21st centuries. At the moment some research is being conducted concerning the inventory and monitoring of flora and plants in the water reservoirs and water streams of the Saratov region. In this work a complete list of water plants and coastal riparian plants is represented. The flora of water vascular plants contains 103 types (including hybrids) of 54 species, 32 plant families and 3 plant divisions. The leading plant families are Potamogetonaceae, Cyperaceae, Typhaceae and Poaceae. The most widespread species are Potamogeton represented by 18 types and 3 hybrids (13 % of all flora). Multi-species are Typha, Carex, Scirpus and Lemna. To identify the proportion of water species in flora of water streams and water reservoirs, the hydrofitness index IHg was used. It showed that the most diverse water flora exist in the Volgograd water reservoir and lakes. In ponds and oxbow lakes coastal plants play an essential role which can be explained by fluctuations in the levels of these water bodies. In water reservoirs and streams of the Saratov region the most highly active ones are Phragmites australis Potamogeton pectinatus, Typha angustifolia, Nuphar lutea, Sparganium erectum. The percentage of active types makes up only 5 % of all water flora. Among registered vascular plants 30 types are included in the Red Book of endangered species of the Saratov region. In the researched flora 9 invasive species were detected, such as Bidens frondosa, Elodea canadensis, Zizania latifolia, Typha laxmannii, Acorus calamus, Hydrilla verticillata, Vallisneria spiralis, Lemna gibba, Lemna minuta.

Environmental Preferences of an Invasive Plant Species, Bidens frondosa (Asteraceae), in European Russia and Western Siberia

To identify habitat conditions, indirect ordination methods on the basis of environmental scales are used widely in Europe. However, many alien plants are absent from those scales. Bidens frondosa (Asteraceae) is an invasive alien species distributed widely in Europe. It is becoming a significant part of natural plant communities, sometimes forming monospecific stands. This study aimed to empirically determine environmental factor values using analysis of the flora accompanying B. frondosa in 22 regions of European Russia collected in a 34-year time span. In European Russia, Tsyganov environmental scales are widely used for such analyses. We determined intervals of values for each environmental factor according to Tsyganov environmental scales, namely thermoclimatic scale (TM: 7.3–9.4), climate continentality (KN: 6.0–9.4), climate aridity/humidity (OM: 6.1–8.6), cryoclimatic scale (CR: 5.3–8.8), soil moisture (HD: 9.9–17.6), scale of the soil salt regimen (TR: 5.1–10.7), soil nitrogen availability (NT: 4.4–8.5), soil pH (RC: 4.8–8.8), habitat shading (LC: 2.0–4.5), and soil-moisture variability (FH: 0.7–5.9). These data on environmental factor values can be further used in ordination analyses of plant communities where B. frondosa appears in the subzone of coniferous-deciduous forests of Eastern Europe. Results of this study demonstrate the ecological preferences of this species and can be used to determine conditions of habitats invaded by B. frondosa.

Annual and biennial invasive species in the flora of Ivanovo

The paper analyzes invasive plant species in a large regional center of European Russia the city of Ivanovo. Based on the conducted research (by 2022) a group of 25 annual and biennial invasive plant species were identified in Ivanovo, which belong to 10 families and 19 genera. The authors have established ecopopological features of successfully naturalized of these species within the city limits, as well as their association with certain natural and anthropogenic ecotopes. 4 most active species (Bidens frondosa, Heraculum sosnowsky, Impatiens glandulifera, I. parviflora) are classified as transformers. They form dense monodominant thickets in various parts of the city, successfully compete and displace species of native flora. The largest number of species occurs in ecotopes, which are characterized by a simplified structure and lability. 17 species are in the composition of natural ecotopes, and the most vulnerable among them are water bodies and riparian communities. Among the anthropogenic ecotopes, habitats (24 species), roadsides (20 species) and wastelands (19 species) are more actively populated by invasive annual and biennial species. The problems of control and management of the spread of invasive species, including a large group of annual and biennial plants, should be solved comprehensively, within the framework of general economic and social urban programs based on scientific monitoring data.

The first checklist of alien vascular plants of Kyrgyzstan, with new records and critical evaluation of earlier data. Contribution 2.

BackgroundWe continue the inventory of alien vascular plants of Kyrgyzstan, with emphasis on the time and pathways of introduction of the species and their current status in the territory. Each taxon is discussed in the context of plant invasions in Central Asia. This work is a further development of the preliminary checklist of alien plants of Kyrgyzstan, which was compiled for the Global Register of Introduced and Invasive Species in 2018.New informationThis contribution includes all alien species of Kyrgyzstan belonging to Solanaceae and Asphodelaceae and one species of Asteraceae. Physalisphiladelphicus (syn. P.ixocarpa) is reported for the first time from Central Asia, as new to Kazakhstan, Kyrgyzstan and Uzbekistan, thus marking a recent invasion with a variety of imported grain and seed material. The old records of P.ixocarpa from Uzbekistan are based on misidentified specimens of P.angulata. Physalisangulata is an old cotton immigrant in Central Asia, whose invasion started in the 1920s; it is excluded from the alien flora of Kyrgyzstan as registered in error on the basis of cultivated plants. Alkekengiofficinarum is an archaeophyte of the Neolithic period in Central Asia, formerly used for food, now strongly declining and largely casual in Kyrgyzstan. The only historical record of Physalisviscosa from Uzbekistan was based on a technical error and belongs to A.officinarum. Daturastramonium and Hyoscyamusniger were introduced as medicinal plants during the period of the Arabic invasion of Central Asia, by the 11th century. Daturainnoxia is a newly recorded casual alien, recently escaped from ornamental cultivation. Nicandraphysalodes is a casual alien, which was cultivated by Russian colonists in the early 20th century for culinary use and is currently used in ornamental cultivation. Hemerocallisfulva was a remnant of historical cultivation in the former Khanate of Buxoro, and its formerly established colonies are presumably extinct in the wild. Bidensfrondosa was seemingly introduced with contaminated forage and seed of American origin during the late Soviet period and started to spread in the period of independence; its invasion in the former USSR is analysed.

Relationship between alien plant invasion and landscape matrix in the water-level fluctuating zone of the Three Gorges Reservoir, China.

Invasive process of alien species is affected by not only the invaded habitats, but also the surrounding landscape matrix. Understanding the effects of landscape matrix on alien species is of great significance for controlling invasive alien species. We surveyed plant communities along the water-level fluctuating zone (WLFZ) of the Three Gorges Reservoir. Invasive status of alien plant species was evaluated. Totally 10 spatial scales of the surrounding landscape matrix in the scope of 2000 m (including WLFZ) were classified, and 14 landscape indices were applied to analyze the landscape matrix composition and configuration. Using the principal component analysis and correlation analysis, the effects of landscape matrix on the alien invasive plant species and associated scale effect were tested. Results showed that a total of 42 alien invasive plant species were found in the WLFZ, belonging to 17 families and 36 genera. Fuling was a dividing place to differentiate invasive species distribution. The number of the alien invasive species between Fuling and the Three Gorges Dam was found more than that between Fuling and Jiangjin. For the all scales (within 2000 m). The higher the landscape matrix fragmentation was, the more difficult the alien species invading. The higher landscape connectivity was, the easier the alien species invading. The effects of landscape matrix composition and configuration on the invasive plant diversity at large scales (1200-2000 m) was more significant than those at small scales (200-1000 m), in which landscape matrix composition and configuration at 1200-1400 m showed the strongest effect, demonstrating a significant spatial scale effect. Different invasive plant species showed the scale effects of landscape matrix composition and configuration. At all scales, Xanthium strumarium and Bidens frondosa showed weak correlations with landscape indices, but Bidens tripartita and Erigeron canadensis showed strong correlations. Landscape matrix was closely related to invasive plant species, and demonstrated a significant scale effect. The alien invasive plant species could be traced to the landscape matrix at large scales. Grassland and forest patches at the small scales could be used as the 'stepping stone' for the alien species transiting before they arrived at the WLFZ. In order to control alien plants in the WLFZ, land-use management and optimization should be strengthened at different scales of landscape matrix on the basis of enhancement of habitat management. A diversified comprehensive control for alien species should thus be taken into account.

Distribution Strategies of Vascular Plants at the Reclaimed Lands at the Saemangum Sea Dike

The distribution of plant communities in the reclaimed land of the southwestern coasts of South Korea, along with the environmental or plant factors, was studied through canonical correspondence analysis (CCA) and the competitor (C), stress tolerator (S), and ruderal (R) (CSR) ecological strategies. The coastal reclaimed land plants were classified into three plant-factor groups in the CCA biplot diagram. Axis1 was correlated with LS, SLA, CH, and FS. Axis 2 was correlated with LDMC, FP, and LDW. The reclaimed landplants were classified into three soil-factor groups in the CCA biplot diagram. First, the group factor was correlated with SAND. Second, the group factor was distributed according to T-N and TOC. Third, the group factor was distributed according to Salinity content. To clarify the relative significance of competition, stress, and disturbance in the distribution process of plant communities, the CSR distribution model was adopted. Sixteen of the 19 species were allocated to the factors related to the ruderals strategies such as R/CR and CR including R/CSR, SR/CSR, and CR/CSR, and SC strategies. They displayed ruderal and competition adaptation strategies reflecting the ecological environment. Seven species showed R/CR (ruderal/competitor-ruderal) strategies; Aeschno meneindica, Chenopodium album var. centrorubrum, Lolium perenne, Lotus corniculatus var. japonicus, Phragmites communis, Portulaca oleracea, and Soncous brachyotus and 6 species showed CR (competitor-ruderal) strategies; Bidens frondosa, Echinochloa crus-galli, Echino chloaoryzicola, Erigeron canadensis, Fimbristy lislongispica and Setaria viridis. The three species with R-related strategies were Artemisia princeps, Lolium perenne, and Trifolium repens. The distribution patterns of the CCA diagrams and CSR triangles may provide a useful scientific basis for protecting and restoring reclaimed lands and their valuable ecosystem services, from the increasing disturbances.

The current status of the plant invasions in Belarus

Abstract This article provides a review of the current status of plant invasions in Belarus. As a result of this research into the alien flora between 2008 and 2020 a list of 52 invasive plant species that threaten biodiversity, human health, and economic has been compiled. About 300 taxa of non-native plants are currently classified as potentially invasive. The list of invasive plant species has been proposed in this article in accordance with trends in the invasive processes is the basis for the monitoring and management of plant invasions in Belarus. The preliminary data from the previous field seasons showed a significant increase in the population abundance and distribution of Swida alba, Rudbeckia laciniata and Artemisia abrotanum. Enrichment of the flora occurs due to the introduction of aggressive plants. Hybridization between native and alien plant species leads to the appearance of hybrids, which often have an invasive potential, and can invade not only disturbed habitats but also natural plant communities. The invasive properties, expansion, and aggressive behavior of these invasive plants of the alien flora of Belarus has led to significant, often irreversible, changes in the natural vegetation and vegetation cover. Invasive species such as Solidago canadensis, S. gigantea, Echynocystis lobata, Impatiens glandulifera are marked by rapid expansion over past decades, and Heracleum sosnowskyi, Solidago canadensis, S. gigantea, Echinocystis lobata, Impatiens parviflora, Acer negundo, Robinia pseudoacacia, Bidens frondosa, have invaded more recently.

BIDENS FRONDOSA (ASTERACEAE), A NEW ALIEN INVASIVE PLANT SPECIES IN THE KURGAN REGION (RUSSIA)

The annual weed Bidens frondosa L. (Asteraceae) has been registered for the first time in the Kurgan Region in 2020 during research on the riverine vegetation of the southwestern part of Western Siberia. This invasive species was found in ten locations along the Iset River banks in the Kurgan Region. We have postulated that the Sverdlovsk Region serves as a source for the B. frondosa invasion into the Kurgan Region along the River Iset. Despite a single short-term field survey, B. frondosa was found in several sites. In the Kurgan Region, this invasive species is characterized by low population density in all plots. Since B. frondosa populations are characterized by much higher density in other regions of European Russia, an increase in the number of locations and density of populations is expected in the Kurgan Region in the future.

NEW DATA ON THE DISTRIBUTION OF RARE AND PROTECTED SPECIES OF VASCULAR PLANTS IN THE LENINGRAD REGION AND SAINT PETERSBURG

New information is given on the habitats, distribution, population status and dynamics of 9 rare vascular plant species. The material was collected through floristic surveys carried out by the author in the Leningrad Region and St. Petersburg, mainly in 2018-2020. One of the species ( Dactylorhiza baltica ) is listed in the Red Data Book of the Russian Federation, three species ( Alisma gramineum, A. juzepczukii, Persicaria mitis ) are red-listed in Saint Petersburg, and two species ( Carex arenaria, Viola persicifolia ) are red-listed in the Leningrad Region. Most of the rare species records were made in the Zapadnyi Kotlin Nature Reserve. In addition, the article presents new information on rare alien species - Ambrosia artemisiifolia, Bidens frondosa, and Erigeron annuus . The invasive status of Bidens frondosa and the dynamics of its distribution in the region are discussed.