Opuntia robusta in length. Yellow, sessile flowers with a fleshy base are produced on the edges of the upper stem segments. These are followed by barrel-shaped fleshy fruits which are pink or purple and up to long. The species was first formally described in 1837 in "Enumeratio Diagnostica Cactearum hucusque Cognitarum". It has naturalised in the states of South Australia, New South Wales, Queensland and Victoria in Australia. Opuntia robusta Opuntia robusta, the wheel cactus, nopal tapon, or camuesa, is a species of cactus in the Cactaceae family. It is native and endemic to central and northern Mexico to within 100 miles
Opuntia arenaria strongly deflexed and much shorter. Overall, plants (clumps) of cladodes may be 20–30 cm across and about 4–8 cm tall. Fruits are small, about 2.5 cm. Opuntia arenaria Opuntia arenaria was considered a variety of "O. polyacantha" by many botanists, and is still treated that way in the Flora of North America. However, "O. arenaria" is diploid and "O. polyacantha" is tetraploid. It was described by Engelmann in 1856. "Opuntia arenaria" can grow in soil that is essentially pure sand. It has rhizomes up to 1.5 m long that give rise to above ground shoots with small cladodes that are