Genus with roughly 126 annuals, perennials or sub-shrub species which develop slightly woody bases. They have creeping or erect growth habits and some species grow along the ground surface, termed prostrate. Species in this genus are adapted to habitats with dry to arid climates and they are found from Africa, through Arabia to Southeast Asia. Flowers are small and delicate, covered in curved hairs and produced in clusters of up to 15 blooms, coloured white with purple venation. These are around 1-2.5cm long and have modified leaves surrounding them called bracts, these are green-brown in colour and possess purple venation. The petals are unequal and lobed, with the outer lobes notably longer than the inner ones.