Tephrocactus is a small genus of 5 species native to Argentina. They are often combined in with the Opuntias, but are different in how they are jointed. The stems grow in very distinct segments, but unlike the flat-pads found on the genus Opuntia, the segments of Tephrocactus are round. Spines may be long, dense and needle-like, or thin and papery, or even absent. They can be short cylinders, egg shaped, or even spherical.
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Name Derivation: From the Greek tephros (ash-colored) and cactus
Tephrocactus is in the family Cactaceae.