Consolea moniliformis

Consolea moniliformis is a species of cactus that is native to the Greater Antilles, on Cuba, Hispaniola (in the Dominican Republic and Haiti), and Puerto Rico (on the islands of Mona, Culebra and Desecheo). The species forms small shrubs, with vividly green falciform pads and is often growing near the coast. On Hispaniola it is often confused with Consolea testudinis-crus a species that forms large tree-like plants with bluish-grey pads, in Puerto Rico it is at times confused with Consolea rubescens....read more on Wikipedia.