A genus of low-lying, small, bushy shrubs found in deserts and arid regions. They have fleshy, opposite leaves, mostly bifoliate, or occasionally with several pairs of leaflets, and often with spiny stipules. The stems are fleshy. The flowers are solitary or paired, terminal, and yellow or white in colour, with a red or purple spot at the base of the petal. There are 4 or 5 overlapping sepals and the same number of petals, which are usually overlapping and clawed. There are twice the number of stamens, held in whorls. The ovary is superior, with 4 or 5 locules, and a simple style with a very small stigma. The fruit is a capsule, angled along the locule partitions, or winged. There are 80 species, found in tropical and subtropical regions of the Old World, and in Australia.
Subjects: Plant Sciences and Forestry.