Solanum rostratum Dunal

8.Solanum rostratumDunal, Hist. Nat. Solanum: 234 (1813). Fig. 10 Type. France. “ In horto Monspeliesi cultum, ” without date, Dunal s. n.. (holotype: MPU). Description. Prickly annual with prostrate or ascending stems up to 150 cm long; prickles basally thickened; indumentum of stellate hairs; leaves green or greyish, pinnatifid with rounded lobes; each cyme of 7–12 flowers; corolla yellow, 25–35 mm in diameter, actinomorphic; one of five anthers longer, 10–14 mm long (all other anthers 6–8 mm long); fruit 9–11 mm in diameter, enclosed in a prickly calyx, dry, irregularly splitting at maturity, sclereidal concretions absent. Taxonomic note. This species has been previously reported as Solanum cornutum auct. non Lam. (Galushko 1980; Poyarkova 1981; Ivanov 2005, 2019; Murtazaliev 2009). Distribution. This species is native to Mexico and the southern states of the USA. It is alien in other parts of North America, Europe, the Caucasus, southern temperate Asia, northern and southern Africa, and Australia (POWO 2025). This drought-tolerant North American species was introduced to Europe (France) in the 1920 s and has since expanded its range to many regions of the world (Ozuzu et al. 2024, with references therein). In Eastern Europe, the species was first collected in Ukraine in 1928. In some regions with arid and semi-arid climates, S. rostratum is an invasive plant, e. g., in deserts and semi-deserts of China (Jian-Xiao and Yimingniyazi 2023; Huang et al. 2024) and many parts of Australia (Purdie et al. 1982). In contrast, it is considered a rare casual alien, e. g., in Uzbekistan (Sennikov et al. 2018; Khassanov et al. 2020). In the forest zone of Europe and North America, S. rostratum is an occasional weed that cannot naturalize in a cold temperate climate (Bassett and Munro 1986; Dzhus 2013). In Russia, the first collection originated from the Republic of Adygea (North Caucasus) in 1924, although Ulianova (1998) specified the first occurrence in 1918, without citing any specimens or references. In European Russia (Fig. 7 D), S. rostratum was mostly found in the southern regions, including the Lower Volga and the plains of the North Caucasus (Poyarkova 1981; Ivanov 2019). The majority of collections date from the 1970 s onward. At the northern limit of its distribution, the species is known from scattered occurrences in Ivanovo Oblast (Borisova 1993, as S. cornutum), Saint Petersburg City (Tzvelev 2000), the Mordovian Republic (Silaeva 2010), and the Udmurt Republic (Baranova and Puzyryov 2012). Ecology. Waste ground, roadsides, and degraded meadows. Residence status. To date, the species is clearly naturalized in semi-desert plains of European Russia (Kalmyk Republic and probably also in the Volga River delta) and adjacent regions of the North Caucasus (Ubushaev et al. 2011). In other areas of Russia, it is a casual alien. Pathways of introduction. Transport – Contaminant: seed contaminant. The species is a grain immigrant in Russia. It was found in waste places at grain-processing factories, at railway stations, and along railways, clearly suggesting its arrival as a grain impurity.