Haploid plants develop from anther culture either directly or indirectly through a callus phase.
Direct androgenesis mimics zygotic embryogenesis; however, neither a suspensor nor an endosperm
is present. At the globular stage of development, most of the embryos are released from the pollen
cell wall (exine). They continue to develop, and after 4 to 8 weeks, the cotyledons unfold and
plantlets emerge from the anthers. Direct androgenesis is primarily found among members of the
tobacco (Solanaceae) and mustard (Cruciferae) families.