How does fertilization take place in marigolds?

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Marigolds are very popular plants in gardens and are very easy to grow. Some even come back the following year as they self-seed. They keep pests away from the garden due to their pungent aroma. They continually bloom, which adds beauty to a garden even at the end of the season.

This flower contains male organs known as anthers, which produce pollen. Pollen contains sperm cells. The female sex organ is called the pistil, and the top of it is known as the stigma. The pollen grains are transferred from the anther to the top of the pistil (stigma) during pollination.

Agents of pollination include insects, birds, wind, and water. Once a pollen grain lands on the stigma, it sticks there and later forms a pollen tube which germinates downward to the style and finally to the ovary within the pistil. Inside the ovary are ovules. These contain eggs. When one sperm cell in the pollen tube joins to an egg cell in the ovule, a zygote is formed, or fertilized egg. Another sperm cell joins to two polar cells in the ovule to form endosperm—a food supply. This is called a double fertilization. The ovule develops a hardened seed coat and becomes a seed. Therefore, a seed contains the fertilized egg and its food supply. This can be planted to start the next generation.

A person with a small paint brush can pollinate a flower by transferring pollen from one plant's anthers to the top of the pistil of another flower. In this way, they could take two different colored marigolds and see the results of a cross-pollination by collecting the seeds that form and planting them. I have attached a link to a diagram showing the sex organs I have described within the marigold flower. This diagram is of a sunflower, but the same organs are present within marigolds.

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