Apomixis in flowering plants exists in two forms:
- gametophytic apomixis
- adventitious (or nucellar) embryony
Adventitious or nucellar embryony occurs in some citrus seeds. Male apomixis also occurs in rare cases, such as the Saharan Cypress where the genetic material of the embryo are derived from pollen. It was also observed to occur in some animals such as water fleas.