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 readily between species. This can make classification difficult, yielding a reticulate phylogeny where different species come together in hybridization. Also, not all species listed here may actually belong in this genus, meaning that "Opuntia" is not a monophyletic group. "Opuntia" also has a tendency for polyploidy. The ancestral diploid state was 2n=22, but many species are hexaploid (6n = 66) or octaploid (8n = 88). Chollas, now recognized to belong to the distinct genus "Cylindropuntia", are distinguished by having cylindrical, rather than flattened, stem segments with large barbed spines. The stem joints of several species, notably the jumping cholla ("Cylindropuntia