Origin and identification
Areces-Mallea described the subspecies in 2001 from the coastal terrace of Little Cayman and the eastern limestone rise of Cayman Brac. The author compared living plants with Caribbean taxa and herbarium material. Cayman plants differ from C. spinosissima in their smooth segment surface, without a strong network of depressions, and a much shorter pedicel-like part at the pericarpel base. [Areces-Mallea 2001]
The description includes upright shrubs 1.5–2.5 m tall. The trunk is distinct and unsegmented, branching mainly near the apex. Typical lateral segments are 20–40 cm long and 6–10 cm wide, with a broader range of variation given in the protologue. Their surface is dull green. Armature and areole elevation change with growth age. [Areces-Mallea 2001, p. 101–103]
Spines and flowers
Trunk areoles were described as containing 6–15 stiff, sharply piercing spines. The nominate subspecies has more numerous, more flexible spines in comparison. In the Cayman subspecies, the flower is shortly bell-shaped and orange-red, and the pericarpel distinctly armed. Comparing flower and adult-trunk traits is more reliable than identification based solely on spine number on a young cutting. [Areces-Mallea 2001]
Mistaken Cayman identifications as C. spinosissima occurred in material from the first collection in 1938 onwards. They do not demonstrate that the Jamaican species' name is a synonym of subsp. caymanensis. Search and the name table retain the distinction between a synonym and an identification error. [Areces-Mallea 2001]
Wynik cytometrii
In the 2007 study, nuclear DNA content indicated 8x. The source table leaves the 2n field blank because it gives no chromosome count for this sample. This is a cytometric estimate of ploidy. It has not been copied as a direct finding of 2n = 88. [Negrón-Ortiz 2007, tab. 1, p. 1363]