It has studied the distribution, the type of expansion and the habitat of the alocthonous species Achillea filipendulina Lam. (iran-turanian element) during-a period of six years (1992-1997) fn the central area of the Iberian Peninsula, This species is in a clear expansion process colonizing border of roadfas, railways and gardens. Its introduction was made in several times in a independent form. The habitat in its origin region does not coincide with the central one. The present distribution do justify its inclusion in the spanish flora.