Ans: Dichogamy is maturation of androecium and gynoecium of a bisexual flower at different periods. It is of two types known as Protandry and Protogyny. Protandry: Androecium attains maturity earlier than gynoecium. It is most common type of dichogamy. Ex: Gossypium, Helianthus, Clerodendron. Protogyny: Gynoecium attains maturity earlier than androecium. Ex: Solanum, Colchicum