(a) Cleistogamous flowers are those which do not open at all and pollen from other plants cannot land on the stigma of these flowers . Thus , in such plants cross pollination cannot occur and only autogamy occurs. Therefore , cleistogamy ensures autogamy .
(b) Cleistogamy has this advantages that the plant can propagate itself under unfavourable conditions and disadvantage is the self pollination occurs which reduces the chances of variation and evolution of genetically superiors progeny.
