The first records of two alien woody species, Cornus alternifolia and Cornus amomum, in Lithuania

Two native species from North America, Cornus alternifolia and Cornus amomum (Cornaceae) have escaped from cultivation in Lithuania and are recorded as new alien species. Cornus alternifolia was found in an alluvial forest habitat in Vilnius, occupying an area of ca. 0.49 ha. The population consists of about 900 individuals of which ca. 100 were growing to 1-3.5 m high, though fruiting individuals were not found. Cornus amomum is recorded from the Siauliai district, on the banks of a water reservoir in a shrub-dominated habitat. The population consists of four mature individuals with fruits and several young individuals grown from seeds. Cornus alternifolia has already been reported to have escaped in Slovakia; Cornus amomum is reported for Lithuania as an escaped plant for the first time in Europe. Both species occupy habitats analogous to their native range and are dispersed mainly by birds. Their naturalization, spread and invasion to natural habitats of temperate regions of Europe is probable. Therefore, the spread of these species should be monitored, and rapid response measures, if deemed necessary, should be taken