Having been developed during the great age of exploration, between the second half of the 19th century and the first decades of the 20th century the gardens became an important point of reference for the bigger botanical gardens of Northern Europe. Because of Palermo's favourable climate, they transferred a good number of unknown, poorly classified and exotic tropical species there. In this context, the relationship between the Berlin Botanic Garden, under the stewardship of Adolf Engler, and those of the originating areas of the new world proved to be extremely important.