Pine cone cactus
Common names: Pine cone cactus, Paper-spine cholla (English)
Segmented, succulent shrublet up to 30 cm high. Stem segments pine-cone shaped, loosely attached to each other and falling easily, with scattered areoles carrying glochids (fine, barbed bristles). Flowers white to slightly pinkish, up to 5 cm long. Fruits almost spherical, dry-walled, brown, up to 15 mm long, opening irregularly to release winged seeds.
Pine cone cactus invades dry watercourses, drainage lines and disturbed sites around human habitation. It spreads from gardens quickly and easily, because the stem segments fall off readily and roll around, rooting where they come to rest.