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 Species distribution and density. Darker squares represent higher density of members of this family. |
Introduction
Aloe family
A relatively small but widespread family of predominantly succulent herbs with a basal or terminal rosette of leaves; best known for the genus Aloe.
Distribution
Widespread in arid and mesic areas of the temperate to tropical regions of the Old World, with the highest diversity in southern Africa, especially in the northeastern parts.
Number of genera in the world
ca. 12
Number of species in the world
ca. 800
Number of genera in the Flora of southern Africa region
9
Number of species in the Flora of southern Africa region
635
Well-known southern African genera
Aloe, Bulbine, Kniphofia
Growth forms
Perennial herbs, shrubs or small to large trees, also a few geophytes and climbers; mostly with a rosette of succulent leaves.
Habitats
Found from arid plains to the marshy areas of high escarpment mountains.
Flagship species
Aloe dichotoma (quiver tree; kokerboom [A]) is a conspicuous constituent of the vegetation of the arid parts of South Africa (Northern Cape) and Namibia. This tree aloe grows up to 9 m tall and bears beautiful yellow flowers during the winter months. The common name refers to the use of the hollowed-out stems as quivers by San hunters. Large trunks of dead trees are also hollowed out and used as natural fridges. In this tree-poor region, sociable weavers often use the quiver tree as structural support for their communal nests.
Significance of the family
Important as gardens subjects (Aloe, Bulbine, Kniphofia), cut flowers (Kniphofia) or as collector's items (Aloe, Gasteria, Haworthia). Members of the family (especially Aloe species) are known to be used medicinally as a purgative, in the treatment of arthritis, eczema, skin irritations, burns, hypertension and stress. The fleshy part of the Aloe leaf (aloe gel) is used in the cosmetics industry and also forms the basis of health drinks and tonics.
Diagnostic characters
Perennials, often with swollen, tuberous roots with yellow sap. Stems, if present, fibrous and woody rather than succulent; usually with basal rosette of leaves , mostly succulent and often with spiny margins . Inflorescences simple or compound racemes or spikes on long peduncles. Flowers regular, with the perianth in 2 whorls of 3 tepals each, often united into a tube or star-shaped . Stamens 6, in 2 whorls of 3 each, inserted below the ovary. Ovary superior � with 3 locules. Fruit predominantly a dry loculicidal capsule .
Did you know?
The medicinal use of *Aloe vera (probably originating from Arabia) has been recorded from China and India about 2 400 years ago.