* Cereus

About 40 species (Caribbean and South America), of which one, Cereus jamacaru (Queen of the night, Tree cactus; locally referred to incorrectly as Cereus peruvianus), is naturalised in southern Africa (in bushveld of Limpopo, Mpumalanga, Gauteng and North-West). It is a declared Category 1 invader plant in South Africa.

* Echinopsis

About 60 species (South America), of which one, Echinopsis spachiana, has become an invasive species in the Eastern Cape and is a declared Category 1 invasive plant in South Africa.

* Harrisia

About 20 species (Caribbean and South America), of which one, Harrisia martinii, has become naturalised in KwaZulu-Natal.  

* Hylocereus

About 18 species (tropical America), of which one, Night-blooming cereus Hylocereus undatus, has become an invasive species in KwaZulu-Natal and Eastern Cape.  

* Opuntia

About 240 species (North and South America), of which about 14 species are naturalised in southern Africa, many of them troublesome invasive species.  Most, if not all, of these species naturalised from garden escapees and in addition there are about a further 24 species that are cultivated in southern Africa as well as numerous garden varieities.

* Pereskia

Twenty species (Central and South America), of which one, the Barbados gooseberry Pereskia aculeata, has become a serious invasive species in the coastal forests of KwaZulu-Natal. It is a declared Category 1 invasive plant in South Africa. There are also an additional four species that are cultivated in southern Africa.

Rhipsalis

About 50 species (Africa, Asia, America), of which one, Rhipsalis baccifera, is indigenous in southern Africa (KwaZulu-Natal and Eastern Cape).  Four other species, originating from South America, are cultivated in southern Africa.

Acanthocereus

Cultivated species: Acanthocereus pentagonus, native from the USA through to Venezuela.

Aporocactus

Cultivated species: Rat's tail Aporocactus flagelliformis and Aporocactus martianus, both native to Mexico.

Ariocarpus

Six species are cultivated in southern Africa.

Astrophytum

Cultivated species: Astrophytum asterias (native to Texas and Mexico), Astrophytum capricorne, Astrophytum myriostigma and Astrophytum ornatum (latter three all native to Mexico).

Aztekium

Cultivated species: Aztekium ritteri (native to Mexico).

Cephalocereus

Cultivated species: Old man cactus Cephalocereus senilis, native to Mexico.

Cleistocactus

Cultivated species: Cleistocactus samaipatanus (native to Bolivia), Cleistocactus sepium (native to Ecuador), and Cleistocactus winteri (native to Bolivia).

Echinocereus

Cultivated species: Echinocereus scheerii (native to Mexico) and Echinocereus viridiflorus (native to central USA).

Echinopsis

Sixteen species are cultivated in southern Africa.

Epiphyllum

Cultivated species: Epiphyllum ackermannii (native to Mexico), Epiphyllum oxypetalum (native to Mexico and Guatamala) and Epiphyllum thomasianum (native to Costa Rica).

Epithelantha

Cultivated species: Epithelantha micromeris (native to SW USA and Mexico).

Eulychnia

Cultivated species: Eulychnia acida, native to Chile.

Ferocactus

Cultivated species: Ferocactus histrix (native to Mexico).

Gymnocalycium

Eighteen species are cultivated in southern Africa.

Hatiora

Cultivated species: Hatiora gaertneri and Hatiora rosea (both native to Brazil).

Lepismium

Cultivated species: Lepismium houlletianum (native to Brazil).

Leuchtenbergia

Cultivated species: Leuchtenbergia principis (native to Mexico).

Lophophora

Cultivated species: Mescal or Peyote Lophophora williamsii, native to Texas and Mexico.

Mammillaria

Twenty-four species are cultivated in southern Africa.

Melocactus

Seven species are cultivated in southern Africa.

Peniocereus

Cultivated species: Peniocereus serpentinus (native to Mexico).

Pterocactus

Cultivated species: Pterocactus fischeri (SW USA and Mexico) and Pterocactus tuberosus (Argentina).

Rebutia

Four species are cultivated in southern Africa.

Schlumbergera

Cultivated species: Christmas cactus Schlumbergera x buckleyi.

Selenicereus

Cultivated species: Night-flowering cactus Selenicereus grandiflorus (from tropical America) and Selenicereus macdonaldiae  (from Honduras, South America)

Stenocactus

Cultivated species: Stenocactus zacatecasensis (native to Mexico).