We enjoy the beauty of flowers without considering how hard they work during their short lifespan. Flowers have two major responsibilities: reproducing plant life and providing food for pollinators. If flowers slacked on either of those responsibilities, the plant kingdom would be in serious trouble.
The structure and parts of a flower enable it to complete the tasks of reproduction and pollen manufacturing with extraordinary efficiency. The plant kingdom is in safe hands (so are we) because flowers are on the job day and night.
Let’s examine the structure and parts of a flower to discover how these beautiful creations reproduce and keep the insect population so well fed.
Four Main Parts
Most flowers have four main parts: sepals, petals, stamens, and carpels.
They are the small, leaf-like parts growing at the base of the petals. They form the outermost whorl of the flower and are the first visible portion of the flower that you see as it forms on the stem. The main function of the sepals is to protect the flower while it’s in the bud stage before it blossoms.
They are the part of a flower everyone knows about – it’s the colored part of the flower and usually the main reason we buy a particular flower. The petal layer lies just above the sepal layer and their main function is to attract pollinators, like bees, birds, insects, and butterflies to the flower. The shape, size, and color of the petals will attract different pollinators to the flower to increase the chances of pollination so the plant can reproduce.
They are the male parts of a flower and are structurally divided into two parts.:
a–The anthers, which is the head of the stamen and located in the center of a flower. This flower part is typically yellow and they are two pollen-filled sacs waiting for pollinators to land on them. Anthers are responsible for producing the pollen which is transferred to the pistil or female parts of the same or another flower to bring about fertilization.
b– The filament, which is the long and slender part that attaches the anther to the flower.
Pistils (aka as carpels)
They are the female parts of a flower and are structurally divided into four parts:
a– The style is a long slender stalk that holds the stigma. When pollen reaches the stigma, the style starts to become hollow and forms a tube called the pollen tube. It takes the pollen to the ovaries to enable fertilization.
b– The stigma is found at the tip of the style and it forms the head of the pistil. The stigma contains a sticky substance. It can catch pollen grains from different pollinators as they land on the flower or as the pollen is dispersed by the wind. The sticky stigma has the responsibility of beginning the fertilization process.
c– The ovary forms the base of the pistil and it holds one or eggs, called ovules, of the flower.
d– The ovules are the egg cells of a flower. When pollination with compatible pollen occurs and reaches the ovary, it will fuse with the ovules to create seeds. After fertilization, the ovule becomes the seed and the ovary becomes the fruit.
Both Male and Female
Most flowers are hermaphrodite and contain both male and female parts. Others may contain one of the two parts and may be male or female.
This is why certain plant varieties must have a male and female to reproduce, bear fruit, and/or produce flowers, while other plants can take care of business all by themselves.
Flowers with all-male or all-female parts are called ‘imperfect’ and include common garden plants like cucumbers, melons, and pumpkin.
Flowers that have both male and female parts are called ‘perfect’ and include dandelions, lilies, and roses.
We have discussed the reproductive structure of flowers. While the main objective of all plant life is to reproduce, it not the only part of a flower. Flowers need a supportive stem and that is called the peduncle. The peduncle, also referred to as the flower stem, is usually green or a neutral color which prevents the pollinators from being distracted by the pollen-rich blooms.
Peduncles usually have no leaves but may have nodes or bracts. Its responsibility is to support the flower and keep it attached to the main plant stalk.
This is the part of the flower located where the peduncle and flower bloom meet. This flower part used to be called the ‘thalamus’ (Thalamiflorae) but has undergone a name change in recent years.
The receptacle is the thickened part of a stem. It’s where the flower organs grow from and is located at the base of the bloom. The receptacle is responsible for keeping the flower in an upright position to attract the pollinators. It also holds all the floral parts together.
In certain food-producing plants, like apples, strawberries, mayhaws, and pears, the receptacle develops into an edible part of the fruit.
When pollen from one flower fertilizes the ovule of another flower, it’s called cross-pollination. This is how we have such a variety of flowers that come in all shapes, sizes, colors, fragrances.
Self-fertilization occurs when pollen from the same flower fertilizes the plant. This leads to inbreeding, plant deformation, and a reduction in diversity among the flowers.
Plant breeders often assist plants in the pollination process. This is to ensure healthy cross-pollination for the survival of strong plant structure and food and floral production.
If you missed Part 2 of 11, “The Systematic Way Plants are Classified”, click here.