Formation of seeds without fertilization is called apomixis. It leads to clonal reproduction in which all offsprings are by and large genetically identical to the parent. The egg contains a full complement of genes and does not need to fuse with a sperm to produce a zygote. Apomixis provides for the perpetuation of traits favourable to individual survival but eliminates the longer-term evolutionary advantage of biparental inheritance. In asteraceae, various genera and individual species of the order asterales are known to reproduce by apomixis (the setting of seeds without fertilization), either completely or in addition to normal sexual means. In poaceae about 35 genera produce seeds without fertilization. On the other hand, parthenocarpy is development of fruits without fertilization. The fruit resembles a normally produced fruit but is seedless, e.g. pineapple, banana, cucumber, grape, orange, grapefruit etc.