Pilosocereus

Pilosocereus (from Latin, "hairy cereus") is a genus of cactus native to the Neotropics. Tree cactus is a common name for Pilosocereus species. The genus Pseudopilocereus is a synonym of this genus. For many years, the illegitimate name Pilocereus was used for this genus, although properly a synonym for Cephalocereus. The commonly cultivated Pilosocereus pachycladus (syn. Pilosocereus azureus) is a blue cactus with hairy areoles that emit golden spines. When mature, most species develop a hairy lateral cephalium either white, golden, brown, or golden brown. A noteworthy example of an exception to this rule is that of Pilosocereus pentaedrophorus. Generally, tubular flowers emerge year-round from the hairy cephalium. These flowers emit off-putting smells attracting flies and bats for pollination. Flowers come in white, pink, and purple too. Generally, Pilosocereus flowers are self pollinating, but there may be exceptions. After pollination, globose fruits an inch or bigger form. When ri......read more on Wikipedia.