Dracaena (plant)
Dracaena () is a genus of about 120 species of trees and succulent shrubs. The formerly accepted genera "Pleomele" and "Sansevieria" are now included in "Dracaena". In the APG IV classification system, it is placed in the family Asparagaceae, subfamily Nolinoideae (formerly the family Ruscaceae). It has also formerly been separated (sometimes with "Cordyline") into the family Dracaenaceae or placed in the Agavaceae (now Agavoideae). The name "dracaena" is derived from the romanized form of the Ancient Greek – "drakaina", "female dragon". The majority of the species are native to Africa, southern Asia through to northern Australia, with two species  in tropical Central America. Description. Species of "Dracaena" have a secondary thickening meristem in their trunk, termed Dracaenoid thickening by some authors, which is quite different from the thickening meristem found in dicotyledonous plants. This characteristic is shared with members of the Agavoideae and Xanthorrhoeoideae among other members of the Asparagales. "Dracaena" species can be classified in two growth types: treelike dracaenas ("Dracaena fragrans", "Dracaena draco", "Dracaena cinnabari"), which have aboveground stems that branch from nodes after flowering, or if the growth tip is severed, and rhizomatous dracaenas ("Dracaena trifasciata", "Dracaena angolensis"), which have underground rhizomes and leaves on the  surface (ranging from straplike to cylindrical). Many species of "Dracaena" are kept as houseplants due to tolerance of lower light and sparse watering. Species. "Plants of the World Online" currently includes: Uses. Ornamental. Some shrubby species, such as "D. fragrans", "D. surculosa", "D. marginata", and "D. sanderiana", are popular as houseplants. Many of these are toxic to pets, though not humans, according to the ASPCA among others. Rooted stem cuttings of "D. sanderiana" are sold as "lucky bamboo", although only superficially resembling true bamboos. Dracaena houseplants like humidity and moderate watering. They can tolerate periods of drought but the tips  of the leaves may turn brown. Leaves at the base will naturally yellow and drop off, leaving growth at the top and a bare stem. Dracaena are vulnerable to mealybugs and scale insects. Other. A naturally occurring bright red resin, dragon's blood, is collected from "D. draco" and, in ancient times, from "D. cinnabari". Modern dragon's blood is however more likely to be from the unrelated "Daemonorops" rattan palms. It also has social functions in marking graves, sacred sites and farm plots in many African societies