From The Art and Popular Culture Encyclopedia
Dracaena (romanized form of the Ancient Greek δράκαινα - drakaina, "female dragon") is a genus of about 40 species of trees and succulent shrubs classified in the family Ruscaceae in the APG II system, or, according to some treatments, separated (sometimes with Cordyline) into a family of their own, Dracaenaceae or in the Agavaceae. The majority of the species are native in Africa, with a few in southern Asia and one in tropical Central America. The segregate genus Pleomele is now generally included in Dracaena. The genus Sanseviera is closely related, and has recently been synonymized under Dracaena in the Kubitzki system.
Dracaena have a secondary thickening meristem in their trunk. This monocotyledonous secondary thickening meristem is quite different from the thickening meristem found in dicotyledonous plants and is termed Dracaenoid thickening by some authors. This character is shared with other members of the Agavaceae and Xanthorrhoeaceae among other related families.