A casual alien plant new to Mediterranean Europe: Ceiba speciosa (Malvaceae) in the suburban area of Palermo (NW Sicily, Italy)

The abiotic and biotic characteristics of the first sites where floss silk tree behaves as a casual alien plant in the Mediterranean Europe are described. The species was probably first planted in botanical gardens of southern France few decades before mid XIX century. It was introduced in Palermo in 1896, a city which appears to match very well its climatic requirements. According to the available information on its biology and ecology in both its original and secondary range, the floss silk tree should not become an invasive alien plant in the Mediterranean. Nevertheless, several gaps need to be filled in order to increase our understanding of future trends of Ceiba speciosa in southern Europe, in particular, the eventual role of pollinators and seed dispersers outside the species’ natural range.