Is there a taxonomic pattern to plant invasions?

Alien floras of 26 regions distributed over the globe and covering a variety of habitats were analysed to assess the role of plant families and higher taxonomic units. Alien species were recorded in 164 families. The highest concentration of families containing aliens was recorded in Caryophyllidae (namely Caryophyllales) and Asteridae. The largest families (Gramineae, Compositae. Leguminosae, Cruciferae) contribute most to the total number of alien species in local Boras. In relative terms, i.e. related to the species pool available as potential invaders, the best invaders belong to Papaveraceae, Chenopodiaceae, Amaranthaceae, Cruciferae, Polygonaceae and Gramineae. Some families depend largely on deliberate introductions of crops and ornamental species, while the representation of others is enhanced when only accidental introductions are considered. The adventive distribution of families, i.e. the regions into which their members tend to invade, reflects their natural distribution. Particular families tend to invade in the regions with conditions similar to those from their native area. The most successful families possess specific features that could be attributed to their invasiveness. However. there is no simple morphological, physiological or ecological character that could be generally related to the invasiveness of the family.