Nowadays, there are 667 exotic species (PDF) referenced in continental Portugal*, which belong to 124 families, corresponding to approximately 18% of the native flora (Almeida & Freitas 2006, 2012). The great majority of the exotic species are Angiospermic (642 species, which represents 96,3% of the total); in a lower number there are the Gymnosperm’s, with 14 species (2,1% of the total) and the Pteridophyte’s with 11 species (summing 1,6% of the total). The most represented families are, in decreasing order: Asteraceae (Compositae) with 71 species, Fabaceae (Leguminosae) with 64 species, Poaceae (Gramineae) with 52 species, Solanaceae (29 species) and Rosaceae (28 species). * the authors include in this number the exotic species that are more or less naturalized. They don’t include many of the species that are found exclusively in gardens.