Structure of a plant [reproduction]

Pollination is the transfer of pollen from an anther to a stigma.

Cross-pollination is the transfer of pollen from the anther of one plant to the stigma of another plant.

Self pollination is the transfer of pollen from the anther to the stigma of the same plant.

Sepals: Strong modified leaves that wrap around the flower as it is developing and forming.
Petals: Modified colourful leaves that are typically found on insect pollinated plants as they attract insects. They vary in size and colour.
Stamens: Consist of the anther and the filament.
Anthers: Male part of the plant where the male gametes, pollen are produced through meiosis.
Filament: This is the stalk that supports the anthers and holds them up. They are typically longer and grow out of the plant in wind pollinated plants.
Stigma: This is the female part of the plant. It produces a two chemical substances which enable pollen to stick to it. It also contains a hormone which enables the pollen to release an enzyme which can allow it to digest part of the style and form a tube down to the ovary of the plant. It has a large surface area in wind pollinated plants.
Style: The style is the large stalk that supports the stigma. It is longer in wind pollinated plants so that it is more accessible and easier for the pollen to stick to it.
Ovary: This is where the ovules are found.
Nectaries: Can be located anywhere on a plant yet they provide glucose to insects in insect pollinated plants who need it for respiration.

Insect pollinated:

1. Large petals
2. Nectaries
3. Powerful scents

Wind pollinated:

1. Stigma with large surface area.
2. Stamens typically stick out of the plant.

Sometimes it is beneficial for the male parts of the flower to develop prior to the female parts. Self-pollination is prevented and the flower will have to do cross pollination. This results in more genetic variation in the species hence a greater chance of it surviving.

An advantage of self-pollination: less energy is required as no petals or nectaries have to be created.