The taxonomic complex Centaurea stoebe s. l. (Asteraceae) in the flora of Ukraine

Nowadays, many biological terms receive new interpretations, especially the concept of species. The species is the main structural unit of living things. It emerges, develops, and, when living conditions change either disappear or transforms into other species. There is no clear and unified definition of species. The achievements of contemporary molecular genetic studies indicate that the majority of microorganisms exist mainly not in a free-floating condition, but in formed associations or consortia. Microbial interactions occur by transferring molecular and genetic information, and various mechanisms such as secondary metabolites, siderophores, quorum-sensing system, biofilm formation, and cell transduction signals can be involved in this exchange. Therefore, for a deeper understanding of the concept of "species" in biology, it is necessary to take into account not only morphological and physiological criteria, but also to consider species from the viewpoint of systems biology, and to bear in mind factors of horizontal gene transfer. Therefore, the concept of "species" can be considered in a broader context, in particular within ecosystems with all assimilation relations.