Taxonomy
Opuntioideae is a subfamily of the big family Cactaceae. In Plant theory 1 Cactaceae was not split in Subfamilies and placed in Subphase 4 in Portulacales.
In Plant theory 2 Cactaceae is split in 4 Subfamilies and Opuntioideae is placed in Subphase 6. The inclusing of Pereskioideae and Maihuenioideae is tentative.
Botany
Globose, solitary, erect, non-ribbed, caespitose, tubercled cactus; stems distinctly segmented,prickly pear growth form; areoles with abundant, painful glochids in addition to normal spines, retrorsely barbed; glochids and spines share the same ontogeny, but glochids remain unsclerified at the base and therefore break off easily.
Pereskioideae: with leaves.
Austrocylindropuntieae: terete stemmed.
Opuntieae: flat stemmed.
Subfamilies
Pereskioideae: Leuenbergeria, Pereskia.
Maihuenioideae: Maihuenia.
Opuntioideae
Austrocylindropuntieae: Austrocylindropuntia,Cumulopuntia, Punotia.
Cylindropuntieae: Corynopuntia, Cylindropuntia,Grusonia, Micropuntia, Pereskiopsis, Quiabentia
Opuntieae: Brasiliopuntia, Consolea, Miqueliopuntia, Nopalea, Opuntia, Salmonopuntia, Tacinga, Tunilla
Pterocacteae: Pterocactus.
Tephrocacteae: Maihueniopsis, Puna, Tephrocactus.