Polygonum orientale (≡ Persicaria orientalis; Polygonaceae) in Turkey re-discovered after 73 years and considerations about its status.
Polygonum orientale (≡ Persicaria orientalis; Polygonaceae), a specie native to a wide region from India to Far East Russia and extending to North and South Australia. For this reason, in here, this taxon is recorded as a new alien species for Turkey. The species was first recorded in Turkey in the Marmara region (Sakarya province, Adapazarı district) in 1936. Subsequently, it was found in the Central Anatolia (Ankara province) in 1942, in the Eastern Black Sea Region (Rize province) in 1945, and finally in the South Eastern Anatolia (Urfa province) in 1947. Our finding represent was the first one in the Western Black Sea Region (Düzce province, Kaynaşlı district), 73 years after its last detection. Information about the current distribution and habitats of this species in Turkey, as well as its complete morphological description, were provided.