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| Pollination |
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| Pollination is defined as the transference of pollen grains from the anther of a flower to the stigma of the same flower or another flower belonging to the same species. Two types of pollinations have been broadly recognised. |
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| fig. 27.65: Pollination |
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| 1. Self- pollination (Autogamy), |
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| 2. Cross pollination (Allogamy) |
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| Self pollination or Autogamy: Self pollination is defined as the transference of pollen grains from the anther to the stigma of the same flower. It takes place in bisexual flowers only. |
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| Geitonogamy: The transfer of pollen grains from anthers to the stigma of another flower borne on the same plant is called geitonogamy. |
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| Xenogamy: The pollination between two flowers on different plants of or the same species is called xenogamy. |
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| fig. 27.66: Pollination |
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| Adaptations in flowers favouring self pollination |
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| There are two important adaptations in flowers favouring self pollination. |
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| a. Homogamy: When the anther and the stigma of a bisexual flower mature at the same time, self pollination is very easily achieved. e.g. Mirabilis, jalapa. |
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| b. Cleistogamy: In few flowering plants like Commelina bengalensis, Arachis hypogaea and in some species of Viola, the bisexual flowers never open. They are called cleistogamous flowers. Within the closed petals, stamens come in contact with the pistil and self pollination is brought about. Flowers that open are chasmogamout. |
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