self-pollination
Most flowers carry both stamens and carpels; however, a few species self-pollinate. These are known as perfect flowers because they contain both types of sex organs Figure 14.25. Biochemical and anatomical barriers to self-pollination promote cross-pollination. Self-pollination is a severe form of inbreeding, and can increase the number of genetic defects in offspring. A plant may have perfect flowers, and thus have both genders in each flower; or, it may have imperfect flowers of both kinds on one plant Figure 14.28 . In each case, such species are called monoecious plants, meaning one house. Some botanists refer to plants with perfect flowers simply as hermaphroditic. Some plants are dioecious, meaning two houses, and have male and female flowers imperfect flowers on different plants. In these species, cross-pollination occurs all the time.