Current State and Distribution of Alien Weedy Cardamine occulta Hornem. (Brassicaceae) in European Russia

Abstract

Cardamine occulta Hornem. (Brassicaceae), an East Asian weedy bittercress, have introduced globally in recent years. First record of this neophyte species in European Russia was made in 2003. According to current data C. occulta was found in nine regions: Leningrad Oblast, Moscow Oblast, Saratov Oblast, Vologda Oblast, Yaroslavl Oblast, the Republic of Karelia, the Udmurt Republic, the city of Moscow and the city of Saint Petersburg. All known populations of C. occulta occupied predominantly man-made habitats. Currently, the species is considered to be a casual or naturalized alien plant. Uncontrollable transfer of the weed along with ornamental plants might lead to its successful spread across the European Russia. Distribution history of the species, as well as a potential for further spread in European Russia are briefly discussed. The main diagnostic morphological features are presented in comparison with those for allied C. hirsuta L. and C. flexuosa With.