A pollen grain landing on the stigma is not fertilisation yet. It still has to germinate a pollen tube that grows down through the style to the ovary, carrying two sperm cells for the double fertilisation characteristic of flowering plants: one forms the embryo, the other the endosperm that feeds it, and only then does the ovule become a seed. Wind-pollinated flowers pay a different price: they give up showy petals and nectar and must instead release enormous quantities of light pollen. And once the bees vanish from the garden, both the fertilisation rate and the seed count fall to almost nothing.
A pollen grain landing on the stigma is not fertilisation yet. It still has to germinate a pollen tube that grows down through the style to the ovary, carrying two sperm cells for the double fertilisation characteristic of flowering plants: one forms the embryo, the other the endosperm that feeds it, and only then does the ovule become a seed. Wind-pollinated flowers pay a different price: they give up showy petals and nectar and must instead release enormous quantities of light pollen. And once the bees vanish from the garden, both the fertilisation rate and the seed count fall to almost nothing.
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