Opuntia abjecta Opuntia abjecta Opuntia abjecta is a short cactus, perhaps to 15(25) cm tall. It occurs in the Florida Keys and has been conflated with "O. triacantha". Recent work shows that the two taxa are distinct. In addition to morphological and phylogenetic (DNA) differences, "O. triacantha" occurs in Cuba, whereas "O. abjecta" occurs in Florida. Currently It is Listed as critically by the IUCN Red List. "O. abjecta" grows on humus over limestone or even on bare limestone. Cladodes are typically 2.5 cm long by 4–5 cm long. The cladodes do not shatter, but do deattach from each other with some
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