Trifolium vesiculosum (Fabaceae) in Ukraine: a new find and historical overview

Trifolium vesiculosum is listed in the current floristic inventories as a species native to Ukraine. In order to clarify the native versus alien status of this taxon, we studied historical and recent literature and herbarium data.We also report here our new record of the species. We found T. vesiculosum in 2020 in Mykolayiv Region (Mykolayiv District, Andriivka village, on the alluvial terrace of the Southern Bug River valley), in a disturbed habitat with predominantly synanthropic and alien species. Previous finds of T. vesiculosum in Ukraine were reported mainly in publications of the 19th century and were based on a few herbarium specimens from the present-day territory of Odesa Region. Due to characteristics of these records, dates and localities of the finds of T. vesiculosum in Ukraine, we have traced its probable introductions during the 19th century in the port of Odesa, on the sand deposits of the Danube River, in the German settlements, and therefore we can confirm the conclusion of Paczoski (1921) who assumed the alien status of the species in Ukraine. Thus, T. vesiculosum is classified as a kenophyte (introduced before 1808). Taking into account the current climatic changes in Ukraine, we emphasize the need for further monitoring of the species, changes in its dispersal strategy, and for registration of its introduction and dispersal pathways.