Thladiantha dubia Bunge

Thladiantha dubia Bunge View in CoL – Fig. 9.

N Cm: Crimea: Simferopol, near Beregovaya Street, 44°55'30.45"N, 34°04'47.11"E, bank of Slavyanka River, 26 Jul 2013, Yevseyenkov (photo: https://www.plantarium.ru/lang/en/page/image/id/199724.html); ibid., floodplain of Slavyanka River before Verkhniy pond, 28 Jul 2013, ruderal vegetation under Salix spp. canopy, Svirin & Yena (CSAU); ibid., near Opytnaya Street, 44°55'36"N, 34°04'49"E, bank of Slavyanka River, 2 Sep 2024, Epikhin (SIMF); ibid., Simferopolskiy district, vicinity of Zhivopisnoye village, 45°01'57"N, 34°10'54"E, wasteland, 6 Jul 2020, Yevseenkov & Svirin (photos: https://www.inaturalist.org/observations/69570466); ibid.,vicinityofZuya, 45°03'00"N, 34°19'33"E, 7Aug2020, Safina (photo: https://www.inaturalist.org/observations /55892034). – Thladiantha dubia , a species of E Asian origin (incl. Russian Far East, Tzvelev 2006; Lu & al. 2011) and sometimes cultivated as an ornamental, is actively naturalized in Europe ( Henning & al. 2017 +). Besides being recorded for Crimea from three localities in the Crimean foothills, this species has been continuously observed since 2013 only in Simferopol, on the narrow floodplain of the Slavyanka River. The area where the species grows has increased from a few square metres to now c. 530 m ². Currently, the population is distributed along the riverbed for c. 80 m. Thladiantha dubia grows here on silt deposits and construction waste, in open seminatural phytocoenoses consisting of Acer negundo L., Salix alba L. and S. cinerea L. with Arctium tomentosum Mill. , Cirsium arvense (L.) Scop., Echinochloa crus-galli (L.) P. Beauv., Persicaria hydropiper (L.) Delarbre, Sium sisaroideum DC. , Solanum nigrum L. and Urtica dioica L. as the herb layer. Plants bloom annually, and there are both male and female individuals in the population. Unlike in other neighbouring regions to the north where T. dubia is known as a strongly invasive species (Vinogradova & al. 2009; Kostruba & al. 2021), its Crimean population is no cause for concern so far. A. V. Yena,

D. V. Epikhin, P. E. Yevseyenkov & S. A. Svirin