Opuntia aurantiaca

Name and classification

Opuntia aurantiaca Lindl.
Family Cactaceae

Common names

jointed prickly-pear

Disseminule

stem segments

Description

A low-growing succulent usually less than 30 cm tall; narrow stems grayish or dark green to purple, with brownish spines to 3 cm long; flowers yellow, fruits red with purple mottling.

Distribution

native to Argentina, Paraguay, and Uruguay

naturalized in Australia and South Africa

Habitat

warm-temperate and subtropical, sub-humid to semi-arid; along streams, grazing lands

General information

Opuntia aurantiaca, a sterile hybrid, does not produce viable seed. Segments of the cactus break off, and reproduction is by dispersal of these spiny segments. The segments are dispersed by wind, attachment to animal hides and tires, or are carried by water. Another major means of dispersal is by humans, who use the plant as an ornamental and discard it in garbage. Segments that come to rest on soil form new roots from areoles on the segment's lower surface, and new stem segments from areoles on its upper surface. Dense stands of entangled spiny stems form an impenetrable barrier and harbor pests such as rabbits. Opuntia aurantiaca has become a serious pest in Australia and is one of the worst weeds in South Africa.

photo: © S. Navie

photo: © S. Navie

photo: © S. Navie

photo: © S. Navie

photo: © S. Navie

photo: © S. Navie

photo: © H.G. Zimmermann

photo: © H.G. Zimmermann