(Anastatica hierochuntica), plant that is the only species of the genus Anastatica, of the mustard family (Brassicaceae), native to western Asia. The small, gray plant curls its branches and seedpods inward in the dry season, forming a ball that opens only when moistened. In this form, it can be stored for years and is often sold as a curiosity. The ball rolls with the wind like a tumbleweed, dispersing seeds as it goes. When moistened, it spreads into a fernlike plant as much as 30 cm (1 foot) wide and bears minute, white flowers.