No, not all flowers show an autogamy mode of pollination. Only a few flowers show an autogamy mode of pollination, like cleistogamous flowers. There are a few characteristics that are necessary to show autogamy. Some of them are:There should be a synchronisation between the release of pollen grains and the receptivity of the stigma of the plant so that pollination can occur.The male reproductive part (anther) and the female reproductive part (stigma) should be close to each other so that the pollen can transfer easily.The phenomenon of autogamy is not possible for flowers where the male and female reproductive parts are exposed.