The embryo is genetically identical to the single parent. For species to maintain its identity and distinctiveness over time, it is necessary for each species to have ways of making sure that it is isolated in some manner from other closely related species. Hybridization can occur when these isolating mechanisms break down. Both interspecific and intergeneric hybrids are known. Unlike animals, hybridization is common in plants.
Sterile hybrids can survive by vegetative growth or apomixis.