Impatiens capensis is an annual plant native to eastern North America that is currently spreading across Europe. In Poland, due to this plant’s rapid spread in the secondary range and high competitiveness in relation to native species, it is considered a locally invasive species. The microstructure of seeds is an important tool for solving various taxonomic problems and also provides data useful for determining the impact of various environmental factors on the phenotypic variability of species. This issue is particularly important in regard to invasive species which occupy a wide range of habitats in the invaded range. There are few reports on seed size and thus far no descriptions of the seed ultrastructure of I. capensis in the analyzed literature. We present new data on the seed morphology of I. capensis growing in different habitats and conditions in the secondary range of the species. The studied populations differed significantly in each of the investigated traits (seed length, width, circumference, area, roundness, and mass). Our findings showed that anthropogenic disturbances in habitats and some soil parameters (presence of carbonates, potassium, loose sand, and moisture) were statistically significant with various seed sizes and morphology in the studied populations of I. capensis. Moreover, our studies showed maximum seed length (5.74 mm) and width (3.21 mm) exceeding those values given in the available literature. For the first time, we also provide a detailed SEM study of the ultrastructure of the seed coat of I. capensis. There are two types of epidermal cells on the seeds: (a) between the ribs (elongated with straight anticlinal walls, slightly concave outer periclinal walls, and micropapillate secondary sculpture on the edges with anticyclic walls), and (b) on the ribs (isodiametric cells with straight anticlinal walls and concave outer periclinal walls). Unlike the variability of size and weight of seeds, the coat ornamentation has turned out to be a steady feature within the studied secondary range of I. capensis.

The study of the semiochemicals produced by the flowers of Impatiens spp. is an important topic that may explain the reason for the rapid expansion of some species in this genus. Impatiens L. belongs to the Balsaminaceae family, which includes several species considered to be invasive plants in Europe. This study aimed to characterize the phytochemistry of four naturally occurring plant species in Poland, including three invasive alien taxa (Impatiens parviflora, I. glandulifera, and I. capensis) and one native species (I. noli-tangere). Gas chromatographic techniques were used to assess phytochemical profiles of chemical attractant cues in their pollination biology. We detected differences in the scent profiles of the investigated species. All the examined Impatiens species produce various alcohols, i.e., heptacosanol, octacosanol, aldehydes (e.g., octadecanal, eicosanal, etc.), and fatty acids, as well as long-chain hydrocarbons such as dodecane, tricosane, petacosane, hexacosane, and farnesene. Impatiens parviflora, I. glandulifera, and I. capensis produce geraniol and linalool, which attract members of the Apidae family, including bumblebees and honeybees. Impatiens parviflora also produces linalool-derived monoterpenes (linalool oxide and 8-hydroxylinalool), which are a strong attractant for Diptera; this may clarify why the species is mainly visited and pollinated by syrphid flies. A list of insect visitors to the Impatiens species under study can be found in the article.

We conducted a literature review on the taxonomic importance of seed micromorphology in the genus Impatiens Riv. ex L. (Balsaminaceae), focusing on studies using scanning electron microscopy (SEM). Of 47 sources, SEM descriptions were available for more than 180 species, revealing significant gaps in micromorphological data within the genus. Our work provides a consolidated resource on Impatiens taxonomy and highlights the need for further SEM studies to improve species identification and phylogenetic analysis.

The riparian tall herb fringe communities of the order Convolvuletalia sepium represent an integral part of the natural vegetation in river valleys. The major objective of this study was to assess the relationships between the diversity and variability of these communities and various environmental factors. The survey was conducted in northwestern Poland, along 101 randomly selected 1–2-km long sections of 24 rivers and the Szczecin Lagoon. Samples were collected in 2008–2013 in all types of tall herb fringe vegetation found in the surveyed river sections. Data collected included hydrogeomorphic variables, soil parameters, potential and actual vegetation, and dominant land use form. A total of 24 vegetation units were documented, based on 300 sample plots (relevés). Tall herb fringe communities occurring in valleys of large rivers (Senecionetum fluviatilis, Fallopio-Cucubaletum bacciferi, Achilleo salicifoliae-Cuscutetum lupuliformis, Convolvulo sepium-Cuscutetum europaeae typicum and chaerophylletosum bulbosi subass. nov., Rubus caesius community, Solidago gigantea community) exhibited floristic and ecological differences in comparison with plant communities from small rivers (Eupatorietum cannabini typicum, aegopodietosum and cardaminetosum amarae subass. nov., Epilobio hirsuti-Convolvuletum sepium, Soncho palustris-Archangelicetum litoralis, Convolvulo sepium-Cuscutetum europaeae aegopodietosum, Urtico-Convolvuletum sepium typicum and aegopodietosum, Urtica dioica community, Galeopsis speciosa community, Rubus idaeus community). This finding fully justified their division into two alliances: the Senecionion fluviatilis and the Archangelicion litoralis, respectively. Significant differences between the tall herb fringe communities associated with large rivers and the plant communities occurring along small rivers included plant species richness, moss layer cover, contribution of river corridor plants, level of invasion, influence of adjacent plant communities on the floristic composition, relative elevation and distance away from the riverbed, degree of shading, proportions of all grain size fractions, soil pH, contents of organic matter, humus, organic carbon, total nitrogen, bioavailable phosphorus, potassium, magnesium, and calcium in the soil. The differences in environmental characteristics of individual plant communities were significant as well; they showed that most vegetation units were well defined. The variables that best discriminated between riparian tall herb fringe communities included the natural potential vegetation unit Salici-Populetum, headwater seeps, soil pH, sample elevation above the river water level, river size, flooding, degree of shading, soil moisture, K2O and CaO contents, and C/N ratio. The integration of the main riparian gradients (longitudinal, lateral, vertical) and patch perspective (e.g., natural potential vegetation units, and land use forms) significantly improved the comprehensive riparian vegetation patterns, because these two perspectives underpin different processes shaping the vegetation. This study contributed significantly to the knowledge of riparian tall herb fringe communities. Two subassociations are described here for the first time, whereas six others have not been previously reported from Poland. The data summarized in the synoptic table indicated that the species diagnostic for individual plant communities should be revised at the supra-regional scale. Some syntaxonomic issues were also determined. The inclusion of the order Convolvuletalia sepium to the class Epilobietea angustifolii resolved the problem of classifying the community dominated by Eupatorium cannabinum, a species showing two ecological optima: one in riparian tall herb communities and the other in natural gaps of the tree stands and clearings of fertile alder carrs and riparian woodlands. This also resolved the problem of classifying the communities dominated by Galeopsis speciosa and Rubus idaeus, intermediate between riparian tall herb and clearing communities. The results of this study may serve as a reference for management of the vegetation in river valleys and promote their conservation. They may also be essential for any future syntaxonomic revision of riparian tall herb fringe communities at a larger geographical extent.

The protocols for in situ hybridization (ISH) techniques can vary considerably; however, they usually include denaturation and hybridization steps. Denaturing compounds are used to reduce denaturation and hybridization temperature, which keeps the proper morphology of the preparation. Formamide is the most commonly used reagent in in situ hybridization to lower the melting temperature. The substitution of toxic formamide for a non-toxic ethylene carbonate at 20 % and 50 % concentration in the hybridization mixture helped obtain a high quality in situ hybridization result with two sequences characteristic for rye, JNK, and Bilby. The results after hybridization, with a duration of 90 min and 16 h, were identical when formamide or ethylene carbonate were used in the mixture. In addition, the toxic formamide was eliminated from the post-hybridization steps and specific hybridization signals for both probes were still obtained.