Description: Succulent spinose shrubs; segments cylindrical, ± circular in cross section, tuberculate but not regularly angled or winged.
Leaves ± terete, falling very early. Areoles rounded, filled with brownish woolly hairs; glochids present but usually small and harmless; spines scattered in the areoles, brown, covered with papery sheaths.
Flowers borne at end of branches.
Fruit ± globose, spineless.
Distribution and occurrence: World: 40 species, southern U.S.A. & Mexico. Australia: several species (naturalized).
Text by G. J. Harden
Taxa not yet included in identification key