Genera : 50 - 56
Species: 3000 +/-
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Economic Uses: Used widely as a source of timber and gum arabic, as well as ornamentals and animal fodder.
Defining Features of Interest: Sometimes catagorized as a subfamily of the Fabaceae along with the Caesalpiniaceae. The family also has nitrogen - fixing bacteria associated with the root nodules that is common to the Fabaceae.
Fossil Evidence: Fossil pollen from the middle and upper Eocene.
Floral Features : Actinomorphic and perfect (rarely unisexual). Flowers small, but in showy inflorescences of heads, spikes or racemes. Hypogynous (rarely perigynous). Stamens are often brightly colored and exerted far beyond the perianth.
Fruit and Seed Features: Fruit a legume or loment. Seeds with a hard coat and little or no endosperm. Placentation is marginal.
Vegetative Features : Habit as shrubs or trees (rarely as herbs). Leaves are bipinnately compound and alternate (rarely opposite). A group of cells which dictate the orientation of the leaves termed a 'pulvinus' is located at the basal end of the petiole.