Mention two strategies evolved by flowers to prevent self-pollination?
Contrivances favouring cross-pollination In many plants there are devices which completely or partially prevent self-pollination and encourage cross¬pollination. Unisexuality: The flowers are unisexual, i. e. stamens and carpels occur in different flowers. They may be present on the same plant, e.g. in maize or on different plants, e.g. in Papaya. The first condition is called monoecious and second is called dioecious. Dichogamy: When stamens and carpels of bisexual flowers mature at different times, it is called dichogamy. If stamens mature first it is called a protandrous condition, or if carpels mature first it is called protogynous condition.
