The flower is the most colorful part of the plants. We find flowers only in angiosperms, the most evolved plants in the kingdom Plantae. Most flowers have four types of structures:
- We are the androecium
- Pistil or gynoecium
When a flower has all these structures, they are said to be complete flowers, for example lilies. In contrast, flowers such as begonia, which do not have petals, or other flowers that do not have any parts, are called incomplete flowers.
|Parts of the flower||Characteristics||Functions|
|Separate it||Modified leaves
Separated or united
|Protect the cocoon|
|Petals||Plans and purposes
Separated or united
|We are the androecium||Present in male flowers||Produce pollen|
|Pistil or gynoecium||Present in female flowers||Produce eggs|
Sepals are modified leaves that surround and close the other parts of the flower as they mature. It is located in the lower and outer part of the flower and together they form what we know as the calyx of the flower.
In general, the sepals are green, thick and waxy. When it has a different color, it is known as a petaloid, for example, the sage cord of Jesus (Salvia leucantha) which has purple sepals.
Its function is to protect the flower bud from the attack of bacteria, fungi and insects. In addition, it keeps moisture inside the cocoon.
The sepals can be:
- Dialyspal: the sepals are separated, as in the sunflower and the rose.
- Gamosépal: the sepals are fused, as in the case of calendula and sage.
The petals are the most striking part of the flower. Together they form the corolla of the flower and the sepals and petals together form the perianth.
The function of the petals is to attract the correct pollinator. This is why they use different strategies, such as the flowers that open at night to say goodbye to fragrances that attract nocturnal animals.
The petals are characterized by being flat and thin. In addition, they may contain pigments that give it its characteristic colors. These pigments can also absorb ultraviolet light, which insects can distinguish.
Not all flowers have petals. Some are wind-pollinated, such as corn and wheat, so no petals develop, as it would be a waste of plant energy.
The petals can be:
- Gametal: the petals appear fused, as in the flowers of the climbing Ipomoea and the pumpkin.
- Dialipeta’l: the petals are separated, as in daisy and magnolia.
The stamens are the androecium or male reproductive organ of the flower. They consist of a filament, which is inserted above the corolla of petals, and a structure called the anther.
The anther is where the pollen is produced. It is composed of diploid cells, inside which are the microsporocytes, which then divide by meiosis to produce four microspores. Microspores will give rise to pollen.
Pollen can travel through the air or be carried by pollinators from flower to flower. This is such a sturdy structure that it can be used to determine the species of plants that existed thousands of years ago.
Dehiscence is the process by which anthers open to release pollen.
The pistil or gynoecium is the female reproductive organ of the flower. They are also known as carpel and are located in the center of it. The pistils have three main parts:
- Stigma: which captures pollen grains.
- Style: support of the stigma that keeps it at a certain height.
- Ovaries: where megaspores occur. Inside the ovary is the placenta, where the eggs are located. An egg develops into a seed after it has been fertilized and the ovary is transformed into fruit.
Male and female flowers
Some plants have female organs in one flower and male organs in another. This is the case with the pumpkin plant.
You may also be interested in:
Mauseth, JD (2016). Botany-An introduction to plant biology, 6th ed. Jones & Bartlett Learning. Burlington, MA.
Salvat, J. (director). (1987). Flower. Saved Encyclopedia of Science and Technology (volume 6, pp.1350-1353). Barcelona, Spain.