sex organ
groups of angiosperms: the monocots and the eudicots. Seed food reserves are stored outside the embryo, in the form of complex carbohydrates, lipids or proteins. The cotyledons serve as conduits to transmit the broken-down food reserves from their storage site inside the seed to the developing embryo. The seed consists of a toughened layer of integuments forming the coat, the endosperm with food reserves, and at the center, the well-protected embryo. Most flowers are monoecious or bisexual, which means that they carry both stamens and carpels; only a few species selfpollinate. Monoecious flowers are also known as perfect flowers because they contain both types of sex organs Figure 26.14 . Both anatomical and environmental barriers promote cross-pollination mediated by a physical agent wind or water , or an animal, such as an insect or bird. Cross-pollination increases genetic diversity in a species.