Expansion of the alien species <i>Rubus procerus</i> (Rosaceae) along railways of the city of Moscow and Moscow Region

Rubus procerus P.J. Müll. ex Boulay was identified as an alien species actively spreading along railways of Moscow and Moscow Region during the early 2020s. This work provides a morphological description of the species, an account of its diagnostic features, an overview of the known localities within the region, and a discussion of possible pathways of its invasion.