Aloe

Aloe also written Aloë, is a genus containing over 500 species of flowering succulent plants. The most widely known species is Aloe vera, or "true aloe", so called because, though probably extinct in the wild, it is cultivated as the standard source of so-called "aloe vera" for assorted pharmaceutical purposes.Other species, such as Aloe ferox, also are cultivated or harvested from the wild for similar applications.The circumscription of the genus has varied widely.Most Aloe species have a rosette of large, thick, fleshy leaves. Aloe flowers are tubular, frequently yellow, orange, pink, or red, and are borne, densely clustered and pendant, at the apex of simple or branched, leafless stems. Many species of Aloe appear to be stemless, with the rosette growing directly at ground level; other varieties may have a branched or unbranched stem from which the fleshy leaves spring. They vary in color from grey to bright-green and are sometimes striped or mottled. Some aloes native to South Africa are tree-like (arborescent). Many genera, such as Lomatophyllum, have been brought into synonymy. Species at one time placed in Aloe, such as Agave americana, have been moved to other genera.The APG III system (2009) places the genus in the family Xanthorrhoeaceae, subfamily Asphodeloideae. In the past, it has been assigned to the family Aloaceae (now included in the Xanthorrhoeaceae) or to a broadly circumscribed family Liliaceae (the lily family). The plant Agave americana, which is sometimes called "American aloe", belongs to the Asparagaceae, a different family.
The APG III system (2009) places the genus in the family Xanthorrhoeaceae, subfamily Asphodeloideae. In the past it has also been assigned to the families Liliaceae and Aloeaceae, as well as the family Asphodelaceae, before this was merged into the Xanthorrhoeaceae.
The genus is native to tropical and southern Africa, Madagascar, Jordan, the Arabian Peninsula, and various islands in the Indian Ocean (Mauritius, Comoros). A few species have also become naturalized in other regions (Mediterranean, India, Australia, North and South America).