First spontaneous occurrence of Centaurea macrocephala (Asteraceae) in Poland.
Centaurea macrocephala Muss. Puschk. ex Willd. (Asteraceae) is a perennial herb native to the Caucasus, Iran and Turkey. It has been introduced as an ornamental plant to Northern, Western and Central Europe, North America and New Zealand. In its primary range, the species occurs in glades of the upper montane zone, tallherb vegetation and subalpine meadows. On secondary habitats, it occurs mainly in abandoned gardens, ruderal habitat, meadows and grassy clearings. In Poland,C. macrocephala is treated as a cultivated species and its naturalisation has not been confirmed so far. In this paper, we report a first spontaneous occurrence of the species in Poland. It was found in July 2018 in south Poland (Korzecko near Chęciny), growing on the secondary grassland near the bottom of an abandoned dolomite quarry. Most likely, the diaspores of C. macrocephala were introduced to the quarry with garden waste. The locality is mapped using the ATPOL cartogram method, photographic documentation of the species and phytosociological relevé documenting the floristic composition and plant cover of its habitat are provided. The species seems to be in an early stage of naturalisation; however, based on our own field observations we suggest that it should currently be classified as a casual alien species in Poland.