Asclepias speciosa in Lithuania
Within the EPPO region, several non-native Asclepias (Apocynaceae) species have been recorded including Asclepias curassavica, A. incarnata and A. syriaca. The latter species is the most widespread species and listed as a species of Union concern (Regulation (EU) 1143/2014). In Lithuania, A. syriaca has been reported to occur in several localities in the south of the country. A survey was conducted to evaluate the distribution of the species, the habitats where the species is present and the potential impact of the species. In addition, herbarium specimens were assessed. During one survey in the district of Alytus, it was evident that plants there showed significant morphological differences compared to A. syriaca at other sites in Lithuania, even though herbarium specimens from the district of Alytus had been identified plants as A. syriaca. Further evaluation showed that the herbarium specimens had been misidentified and the species was A. speciosa. Further herbarium studies showed that A. speciosa was first collected in Lithuania in 1962 in the Žuvintas mire (Alytus district) and a number of additional misidentifications has occurred in recent years.In the south of Lithuania, A. speciosa flowers abundantly in the studied population in the village of Liepakojai, however, there were no developed fruits in September 2018 and thus the colony survives and expands by vegetative renewal, spreading by long rhizomes. The authors note that A. speciosa can be considered as naturalized in Lithuania and this is the first record of its occurrence in Europe. It is likely that the species was introduced into Lithuania as an ornamental species around the end of the 19th century. It is possible that further populations of the species occur within Europe and may be misidentified as A. syriaca. Therefore, further surveys should be conducted to assess its distribution.
Sources
Gudžinskas Z, Petrulaitis L, Žalneravičius E (2019) Asclepias speciosa (Apocynaceae, Asclepiadoideae): a rare or unrecognized alien species in Europe? PhytoKeys 131, 29-41