Continuing with the series of publications on the flora of the province of Soria (Spain) that precedes the review and reedition of the Floristic Catalogue of Soria (SEGURA & al., 2000), 25 taxa are incorporated, corresponding to vascular plants, which had not previously been recorded. A part of them are neophyte species from America or southern Africa that have recently appeared; others are weed, ruderal or road flora of paleotempered origin (Latecircunmediterranean Iranoturanian). All of them provide with an enlargement of their known distribution area, or with an improvement in the knowledge of their means and paths of expansion. The recent creation of big communication infrastructures such as highways or high-speed trains, or the development of a matted net of interregional and international markets of forest or agricultural products, together with climatic change, have facilitated the progress and genetic flux of neophyte or ruderal species between geographically distant areas. In the province of Soria, such arrival of new species that is facilitated by climatic change is more evident in zones of climatic transition of the iberoatlantic area, and between the mesomediterranean and supramediterranean levels.