Taxonomic revision of the genus Amaranthus (Amaranthaceae) in Bosnia and Herzegovina

A taxonomic revision of the genus Amaranthus (Amaranthaceae) in Bosnia and Herzegovina is here presented. Field surveys were carried out during the period 1997–2020. Collected exsiccata are kept at the Herbaria RO and SARA. Both European and American herbaria, as well as extensive literature were analized. Fourteen non-hybrid taxa are recognized as spontaneous; a further species, A. tricolor, is currently known as cultivated only. Two taxa (A. blitum var. blitum and A. graecizans subsp. sylvestris) are native, whereas the other ones are to be considered aliens, mostly neophytes native to the Americas. Four taxa (A. baileyanus, A. blitoides var. blitoides, A. emarginatus subsp. emarginatus, and A. emarginatus subsp. pseudogracilis) resulted as new for the flora of Bosnia and Herzegovina. Data about nomenclature (accepted names, main synonyms, and types), morphology, chromosome number, chorology (for native taxa) or alien status (for exotic taxa), occurrence in Bosnia and Herzegovina, ecology (preferential habitat, phenology, elevation), and taxonomic annotations are provided for each taxon, as well as original photos were prepared. A diagnostic key is proposed.