Materials to the list of invasive species of Orenburg region flora. Message 1
“Black books” and lists of invasive plants play a large role in the information on danger of biological invasions (invasion of alien plant species into ecosystems or animals causing undesirable biological transformation). A preliminary list of invasive plant species of the Orenburg region was published by the authors before. The present article submits the addition to the list. The article provides the data on more than 100 localities and also on biological features and types of habitats and distribution of 13 invasive plant species: Bromus tectorum, Centaurea diffusa, Cuscuta campestris, Echinocystis lobata, Elaeagnus angustifolia, Helianthus lenticularis, Hordeum jubatum, Iva xanthiifolia, Lepidium draba, Rhaponticum repens, Sisymbrium altissimum, S. volgense and Xanthium albinum in the territory of the Orenburg region from which 5 species belong to the first hazard class, 2 - to the second, and 6 to the third. Such species as Bromus tectorum, Centaurea diffusa and Sisymbrium altissimum are included into the black list of the Orenburg region for the first time.