Distribution and invasiveness of Xanthium species in the territory of Bosnia and Herzegovina

Xanthium species are native to America, although it has been shown that reintroduction has occurred between the Old and the New World. Owing to the selective colonization of certain genotypes, these species are adapted to different habitats and have so far successfully colonized a vast number of habitats in many countries. Although Xanthium species can be used for medicinal purposes (extracts of X. strumarium have been used for cancer treatment, because they inhibit the development of cancer cells and are also used for treating inflammatory diseases), due to its toxicity (high amounts of carboxyatractyloside) and wide distribution in agricultural, ruderal and coastal areas, in most countries they are characterized as invasive weed species. These species invade many different crops, such as maize, wheat, soybean, potato, sunflower, tomatoes, tobacco, rape, orchards and vineyard, and can sometimes also be found in grain crops, when full tillering fails to occur. Nomenclature and identification of the plant material follows modern systematic principles according to Kiraly (2009) and the Plant List (2019). The distribution of the identified species is presented on UTM (Universal Transverse Mercator) maps. The distribution of the studied species was presented with the digital elevation model (Digital Elevation Model, DEM) of B&H with a resolution of 20x20 m in a 10x10 km grid. Quantitative representation of Xanthium species was done by a modified Braun Blanquet (1965) model. This work represents a detailed study of the distribution of Xanthium species in the territory of Bosnia and Herzegovina (B&H). In the study are, morphological determination has confirmed the presence of two species: X. spinosum and X. orientale. Within the species X. orientale, two subspecies were identified: X. orientale L. subsp. italicum (Moretti) Greuter and X. orientale L. subsp. riparium (Čelak.) Greuter.. Based on the results of the distribution and number of identified species, it can be concluded that in the studied area X. orientale subsp. italicum is a widespread weed species . Even though X. orientale subsp. riparium was found on only one location, due to the occurrence of cross-polination between subspecies, and even species, it can be said that the species X. orientale has an invasive character. Considering that the presence of X. spinosum was ascertained only in the southern parts of B&H, it can be characterized as a harmful weed species which is not in expansion.