Mexico has the largest number of cacti species on the planet, as well as an enormous diversity of species from other succulent families, with their strange shapes and surprising colors. Little known and scarcely valued, many of them are species in danger of extinction, due to changes in land use, urban expansion and illegal extraction and trafficking.

A primary mission of the Botanical Garden is the conservation of these species. So it has integrated a collection of Mexican succulents belonging to different families. The promoter of this task was the outstanding cactologist Charles Glass, curator of the Botanical Garden until his death in 1998. His initiative has been complemented in subsequent years by other scholars and lovers of Mexican succulent flora.

Most of the botanical collection is made up of specimens collected in various regions of Mexico, belonging to succulent families, such as cacti and agaves, among others, with special attention to our semi-desert region, that is, the north of the state of Guanajuato and areas adjacent.

This extensive work has implied links with rural communities as well as scientific institutions, and a close relationship with the federal environmental agency (SEMARNAT), which has granted the Botanical Garden legal custody of the collection under the category of Management Unit for Wildlife Conservation (UMA).

El Charco's botanical collection represents the biodiversity at risk of the country and the region. It is permanently studied in the Science Unit of the Garden and exhibited in the Conservatory of Mexican Plants and other areas of the reserve. It also forms the genetic basis for propagation in El Charco's nursery, whose specimens are for sale at the reception of the Garden.