What is a flower?
The word comes from the Latin name of the Italian goddess of flowers, Flora. It can also form the Middle English word flour. The scientific definition of it is given as: A flower is a reproductive part found in plants that has the function of helping in the process of reproduction in plants. Flowers have got a mechanism that plays a vital role in the union of sperm and egg. Apart from assisting in the process of reproduction, it is also a symbol of romance and acts as a source for many animals.
What is pollination?
Pollination is the movement of pollen from the anthers to the stigma. Usually, a flowering plant depends on external factors such as wind, water, and especially insects, but animals such as birds and bats can also be employed. The process of pollination only takes place when the flower is fully developed and expanded and such a period is called anthesis. Flowers have different designs to attract animals or insects for the process of pollination. The different types of pollination are as follows:
- Self-pollination
- Cross-pollination
Self-pollination: It occurs when the pollen from the anther is deposited on the stigma of the same flower or another flower on the same plant. It appears when the carpel and stamen mature at the same time. It is a simple process and does not require much from the plant. But it is not a desirable process and has many disadvantages. In fact, plants have developed many mechanisms to avoid it.
Cross-pollination: It is the transfer of pollen from the anther of one flower to the stigma of another flower on a different individual of the same species. It is an excellent process and has a lot of benefits.
Parts of a flower:
A flower mainly has 4 different parts. These are as follows:
- Sepals
- Petals
- Stamens
- Carpal
Sepals: These are leaf-like structures that protect the flower in the bud stage and they may be of different colors depending on the plant. In some plants, they evolve into bracts. The plants that do not have petals are more colored to attract pollinators. The outer whorl of sepals is called the calyx.
Petals: It is considered an essential part of a flower because it is very colorful and has a lovely smell. Its primary function is to attract pollinators for the process of pollination. The outer whorl of petals is called corolla and calyx and corolla together make up perianth.
Stamens: It is the male part of a flower. Each stamen has a tubular filament with another sac at the top. The function of the anther is to produce pollen grains. The pollen grain contains a vegetative cell and a generative cell. The vegetative cell forms the pollen tube and the generative cell fertilizes the female egg.
Carpel: It is the female part of the flower and has a base called the ovary, which contains female reproductive cells called ovules. It also includes a tube called style, which opens up on the surface, which is called stigma.
Types of flowers:
There are many types of flowers based on the presence or absence of specific characteristics. Details about them are given below:
- Incomplete flower:
When any of the four whorls are absent in flower, then it is said to be incomplete. Examples include:
- Polyanthus (calyx absent).
- Beta (corolla absent).
- Cucurbita male flower (gynoecium absent).
- Female flower (androecium absent).
- Bisexual or Hermaphrodite flower:
When the flower contains both female and male parts in it, it is called a bisexual flower. Examples include Hibiscus (China rose) Brassica (mustard).
- Unisexual or Diclinous flower:
When either of the male or the female reproductive organ is absent, those kinds of flowers are said to be Unisexual or Diclinous. Examples include staminate and pistillate flowers of Cucurbita (gourd).
- Regular or Actinomorphic flower: When a flower contains all the members (viz., sepals, petals, stamens, carpels) in equal size and shape and equidistant from each other, these types of flowers are regular flowers. Examples include Hibiscus (China rose); Datura.
- Irregular or Zygomorphic flower: A flower is said to be irregular when the floral members vary in their size and shape. Examples include Pisum sativum (pea).
- Monochlamydeous flower: When calyx or corolla is absent from the flower, such a type of flower is called a Monochlamydeous flower. Examples include polyanthus (tuberose).
- Nude flower: The types of flowers are said to be naked because neither calyx nor corolla is present, for example Male flowers within the cyathium.
Difference between staminate and pistillate flowers:
Staminate flower:
Staminate flowers are type of unisex flowers. These flowers only have male reproductive parts of the flower, stamen. Hence these flowers are also known as androecious flowers. Staminate flowers completely lack female reproductive parts, carpels. Thus technically these flowers can only undergo cross pollination. but when a pistillate flower is present on the same plant, these can even undergo self pollination.
Pistillate flower:
Pistillate flowers are also unisex flowers like that of staminate flowers. but unlike staminate flowers these do have functionally active carpel, that is female reproductive parts of the flower. Pistillate flowers lack stamen. thus like staminate flowers, these will undergo self pollination when the staminate flower is present on the same plant.
Here one can easily differentiate between staminate flower and pistillate flower.
Staminate Flowers | Pistillate Flowers |
|
|
| 2. They have active petals. |
3. They have pollen grains. |
|
| 4. Example: squash. |
Conclusion:
This article will get to know what a flower is, its function, and parts of a flower. We also got to know about the process of pollination and its types. Lastly, we will get to know the types of flowers, and the difference between staminate and pistillate flowers.
Also see:
- Difference between karyokinesis and cytokinesis
- Difference between biochemical oxygen demand and chemical oxygen demand
- Difference between absolute poverty and relative poverty
- Difference between meristematic tissue and permanent tissue
- Difference between random sampling and non-random sampling
- Difference between vegetative cell and generative cell
- Difference between parenchyma and collenchyma cells
- Difference between kwashiorkor and marasmus