Euphorbia nutans Lag.

(≡ Chamaesyce nutans (Lag.) Small) – Fig. 2.

A Cm: Crimea: Bakhchysaraiskiy district, Mostovoye, near railway bridge across Kacha river, 44°43'28''N, 33°48'47''E, 100 m on railway tracks and railway embankment, 11 Sep 2021, Kashirina (photo: https://www.inaturalist.org/observations/94675634); ibid., Zheleznodorozhnoye, 44°43'27.90''N, 33°48'46.98''E, 100 m, on edge of railway, 12 Sep 2021, Svirin & Kashirina (YALT); ibid., 12 Sep 2021, Svirin (photo: https://www.inaturalist.org/observations/94826070); ibid., 20 Nov 2022, Kashirina (photo: https://www.inaturalist.org /observations/145647341).

– This species is native to SE North America, Central America, N South America and the Caribbean. As an alien it is widespread in subtropical and warm-temperate regions of the world, especially in the Mediterranean basin, C and SE Europe and W Asia (POWO 2023a). For E Europe, two localities in S Russia are known: in the Lipetsk region and near Volgograd (Geltman 2012b). The region closest to the Crimean localities of Euphorbia nutans is NW Caucasus (Zernov 2006; Geltman 2012a). Presumably the species was recently introduced to Crimea from there by rail. It is known that railroads are one of the main routes of distribution of E. nutans (Geltman 1996; Somlyay 2009), as well as of some other alien species of the genus in Europe (Brandes 1993; Eliáš 2009; Sîrbu & Şuşnia 2018; Májeková & al. 2021). In Crimea, it was in these habitats that E. davidii Subils and E. glyptosperma Engelm. were first discovered a few years ago (Greuter & Raus 2011; Raab-Straube & Raus 2019). Euphorbia nutans differs from the other species of Euphorbia subg. Chamaesyce Raf. that are known in the region by its larger size, erect or ascending main stem, and some more subtle morphological features (Geltman 1996; Pahlevani & Riina 2011; Sîrbu & Şuşnia 2018). In Crimea, it is a casual alien. In 2021–2022 the population included approximately 20 individuals.

E. Kashirina, S. Svirin & L. E. Ryff