Opuntia aurantiaca

O. aurantiaca is an inconspicuous, perennial succulent shrublet which seldom exceeds 0.5 m in height in open pasture but can reach up to 2 m when supported in vegetation. Plants consist of one to 100 or more spiny, sausage-like, fleshy segments or joints (also known as cladodes). These are 50 to 200 mm long (but may be longer when growing under shade) and 10 to 30 mm wide. Young segments are bright green and flattened whereas older joints are often cylindrical with a corky surface. Segments covered by soil may lose thorns and resemble an underground tuber. If above-ground parts die, or are removed, plants may grow from these underground segments. Green segments take on the function of true leaves that are only present on newly formed segments and fall away within a few months. During periods of drought, or when exposed to direct sunlight, segments take on a more reddish to purplish colour. Joints are easily detached from the parent plant and in wet conditions quickly take root when in contact with the soil surface. Flowers are bright yellow (not orange as is suggested by the species name). Fruit are initially green but are red to purple and club-shaped with age. Each fruit may contain several sterile seeds. Fruit can also take root, in a similar way to segments, when falling to the ground. Reproduction of this cactus is entirely vegetative. Sharp spines arise in groups from areoles, which also contain minute thorns or glochids. Long spines have minute, backward-directed barbs at their extremities. These can hook onto passing objects, mainly animals, facilitating dispersal of isolated joints.