BIOL 1902 Lecture Notes - Lecture 20: Silene Latifolia, Sequential Hermaphroditism, Pollen Tube
19 Apr 2016
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Document Summary
The pollen lands on the stigma and then the stigma develops. To avoid self pollination there has to be a chemical agreement where they make sure they can mix before the pollen tube grows. Sometimes there is a partial agreement but then the pollen tube dies because the pollen is native to that specific plant. Hermaphroditic flowers can also be called perfect flowers because they have both sexes. The female flowers up on the top of the tree because the pollen is carried by wind, and if the male was on top then its own pollen would fall on itself. Separation through time, the sexes can change from one to the other. (jeweled flower) once the flowers pollen has been taken the male part falls off. In spiral flowers the lower flowers open first and are functionally male with pollen blocking the nectar. Once that pollen is removed the flower becomes functionally female.
