Reproduction is one of the most important functions of all living beings. Understanding plant reproduction is of fundamental practical importance for improving the utility of the plant. Angiosperms (flowering plants) form the largest division in the plant kingdom comprising about 250,000 species. Angiosperms are incredibly diverse in size and form ranging from species of Eucalyptus trees well over 100 meters tall to some duckweeds that are barely 1 millimeter in diameter. Other forms include epiphytic vines, succulent cacti, non-photosynthetic parasites and insectivorous plants. These are also major food source for animals and humans, as well as major economic source for the production of various commercial products. Flowers are the reproductive structures of Angiosperms. The function of a flower is to produce reproductive cells in a plant such as eggs and pollens which produce seeds, the dormant young plant of the next generation. The seeds of the plants contain embryo and endosperm. Embryo gives rise to young plant called seedling where as the endosperm provides nourishment to the developing embryo. The embryo and endosperm of a seed can be formed in two ways, by normal sexual reproduction (amphimixis) or by asexual reproduction (apomixis).
