|Naming and discovery|
Cylindropuntia (chollas) is a genus of cacti in the Opuntioideae subfamily. They were formerly treated as a subgenus to Opuntia, but were removed because of their cylindrical stems, and the presence of papery epidermal sheaths on the spines. A few species of mat or clump opuntoid cacti are now placed in the Grusonia.
There are 42 known species in the Cylindropuntia genus, found in the US, Mexico, and parts of South America.