Spotted milk thistle (Silybum marianum (L.) Gaertn., Magnoliophyta, Asteraceae) in south Karelia (Prionezhsky district)

In 2024, on the outskirts of the village of Shuya (Prionezhsky district of the Republic of Karelia) in the ruderal habitat (61,886184° N, 34,258252° E), a massive growth of the medicinal and ornamental plant milk thistle (Silybum marianum (L.) Gaertn., Asteraceae) was discovered. Single specimens of milk thistle were found here in previous (2022-2023) years. This species has not been recorded for the flora of the republic, and its discovery deserves attention from the point of view of the dynamics of the regional flora. The height of generative plants reached 1,7 meters, the weight of 1000 seeds in the upper inflorescences was 20,9-31,0 g, in the lower ones - (5,1-6,2) g, the number of fruits per plant was 601-909. In terms of the number of fruits in the upper inflorescences and their weight, “Karelian” plants are slightly inferior to those of the more southern regions of Russia. Differences are manifested in the ripening of fruits: in northern conditions, fruits fully ripen only in the uppermost inflorescences, the first in time of formation. In the lower inflorescences, full fruit ripening does not occur, the weight of the fruit is much less.The stability of the spotted milk thistle population in the habitat will depend on the safety of seeds during the winter and the success of seed renewal in subsequent years.