A magnificent and luxurious structure of 1788, it houses collections of great importance. It covers a surface of about 16.000 square meters. 

The Hortus Generalis features many exotic plants, while the Hortus Siculus shows the spontaneous Sicilian species. A humid hot greenhouse is used to reproduce the seed of the palm tree and to cultivate exotic plants. Aquatic plants are cultivated in three big circular pits. You can count about 2000 species among which fifty species of palm-trees sometimes of huge dimensions.

The Herbarium is situated in a neoclassical building in the centre of the Botanical Garden. As you enter the forecourt you can see the gardens. It is a structure designed for the collection and maintenance of dried plants. Together with the Botanical Garden, which is a system for the preservation of living plants, the Herbarium is the final accomplishment of the botanical gardens. There are historical and recent collections for a total amount of 150.000 species, from Sicily and all over the world, which are distributed in 80 show-cases.