Resumen de The alien species of Heracleum (Apiaceae) in the Bulgarian flora revisited

Vladimir Vladimirov, Antoaneta S. Petrova, Zhivko Barzov, Zigmantas Gudžinskas

• The genus Heracleum (Apiaceae) is represented by four native species in the Bulgarian flora. In 2017, an alien species, H. sosnowskyi, was reported for the first time for Bulgaria in Acta Zoologica Bulgarica, Suppl.

  9: 47–51, 2017. However, further studies have revealed that the species was misidentified and the reported plants from Sofia City in fact belong to H. mantegazzianum. In summer 2018, both H. sosnowskyi and H.

  mantegazzianum were found in the Rhodope Mts. The population of the former species comprised a few thousand specimens spread in grasslands, arable land and along three confluent local rivers, whereas the latter species was represented by only a few specimens. The specimens of both alien species outgrew any of the native herbaceous plants and reached a height of over three meters. The article presents the currently known distribution of the two species in the Bulgarian flora and the main distinguishing characters between H. mantegazzianum, H. sosnowskyi and the native Heracleum species. Some data about the populations, local spread and impact of the alien Heracleum species in Bulgaria are provided. The text is illustrated with photographs from the Bulgarian localities. Diploid chromosome number, 2n = 2x = 22, is reported for H.

  sosnowskyi for the first time from a naturalised Bulgarian accession.