The cacti in the collection (more than 500 species) vary in shape and size: tall columns, round barrels, shrubby and clustering plants and many smaller species with dazzling flowers. Among the larger plants, of particular interest is the "old man cactus" (Cephalocereus senilis), with its stems covered with long white hair, which can grow up to 15 meters high in the wild. Flanking the entrance of the garden is a fence of organ cactus (Pachycereus marginatus) with its columns edged with fine spines, next to a creeping species, (Stenocereus eruca), covered with dagger-like spines, which grows along the ground, rooting as it goes.


Among the larger barrel cacti is the acitrón (Ferocactus histrix), which is used to make cactus candy and is native to the Charco del Ingenio, along with other species that came to the garden as the result of rescue efforts, such as theGolden Barrel (Echinocactus grusonii) with its notable golden crown. Another species, perhaps the largest of all, Echinocactus platyacanthus, has massive stems that can reach up to 2.5 meters in height.

Shrubbier species include a variety of prickly pear cacti and their relatives (genus Opuntia), both natives and guests in the botanical garden. Some have dense spines and others provide pads and fruits that form part of the common diet of local people. The very eye-catching genus Echinocereus, with clustering pads that expand a meter or more across, are covered by a mass of large pink flowers in the spring.


The collection also includes climbing and trailing cacti (Selenicereus sp., Peniocereus serpentinus and several species of the genus Acanthocereus), the majority of which have large, white nocturnal flowers.

Foto Patricia Lagarde, Historias de un Jardín charco del ingenio Ed. Santillana

Among the smaller cacti, the genus mammillaria is outstanding for the diversity of its forms and flowers. More than 180 species are well represented in the collection. This includes larger species such as M. melanocentra, M. compressa, M. magnimamma and M. spinosissima and smaller ones such as M. marcosii, a beautiful plant with colored spines discovered in the garden under the curatorship of Charles Glass, and  Mammillaria plumosa, with its cotton-like spines. Also included are miniatures, which are notable for their spines and flowers, M. albiflora. M. saboae s.p. goldii, and Mammillaria luethyi.


The richness of the collection also includes other genera, with impressive species such as Astrophytum ornatum, with its large speckled stems and A. myriostigma, a squat plant without spines that is covered with tiny woolly spots. More than eight hundred examples of Pelecyphora asseliformis are planted in and around the Conservatory, their low bodies camouflaged in the gravel. These plants were rescued from a road-widening project some years ago.

The genera Coryphantha, Echinocerus and Thelocactus are well represented, as well as Ariocarpus, Obregonia, Epithelantha, Turbinicarpus, Aztekium, etc., including specimens of Geohintonia mexicana, a new genus of Cactaceae recently discovered in the last decade of the 20th century.

    Foto Patricia Lagarde, Historias de un Jardín charco del ingenio Ed. Santillana