Here are the 9 parts of a hibiscus flower:
- Corolla
- Calyx
- Female Organs (Pistil)
- Stigma
- Style
- Ovary
- Male Organs (Stamen)
- Anthers
- Filaments
So if you want to learn all about the parts of an hibiscus flower, their names, and their functions, then this article is for you.
Keep reading!
Table of Contents
- #1 Corolla
- #2 Calyx
- #3 Female Organs (Pistil)
- #4 Stigma
- #5 Style
- #6 Ovary
- #7 Male Organs (Stamen)
- #8 Anthers
- #9 Filaments
#1 Corolla
The corolla consists of all the petals in the flower. The petals are usually colored and wrap around the reproductive organs. This is why the corolla is often described as the second whorl.
The petals in the corolla can be either free (a polypetalous corolla) or fused together (a gamopetalous corolla). In the case of the hibiscus, the corolla is gamopetalous.
The corolla of the hibiscus is its most characteristic feature. As the hibiscus starts blooming, the petals start growing.
The petals consist of two components; the limb and the claw. The limb is the upper part of the petal. It’s larger than the claw, which is the basal part of the petal. The claw is slender, almost stalk-like.
There are five colorful petals on the hibiscus. Depending on the species, the petals can be red, blue, purple, or pink.
This is due to water-soluble pigments like carotenoids, anthoxanthin, and anthocyanin. The vibrant colors are essential for flower reproduction, better known as pollination.
There are also nectaries on the petals. These sugar-rich tissues are responsible for drawing the pollinators.
Lastly, the petals are a crucial element in the protection of the floral parts in the hibiscus.
#2 Calyx
The calyx comprises the green structure that appears under the corolla. These green structures resemble the petals and are called sepals.
Similar to the petals, there are five sepals that surround the corolla. The sepals are considered the outermost whorl of the hibiscus. They’re not colorful like the petals. Instead, their color is green like the stem and leaves.
If you look at a sepal under the microscope, you’ll notice it’s much thicker than the leaves. It also shows veins and comprises stomata.
The sepals are intact and present before bud formation. This is to ensure the petals remain protected until maturity. The sepals also protect the petals after the bud blooms.
Once the flower blooms, the calyx starts extending from the base of the flower. The sepals remain intact even after the petals have fallen off.
#3 Female Organs (Pistil)
The female reproductive organs of the hibiscus go by many names. They’re called the pistil, carpel, or gynoecium.
This structure consists of the stigma, the ovary, and the style. The base of the pistil is supported by the thalamus or pedicle. The pistil itself is located at the center of the flower.
#4 Stigma
The stigma is the uppermost structure of the pistil. This is why it’s commonly referred to as the “head of the pistil.” It’s a sticky platform that’s always exposed to the surroundings. It transfers the pollen to the ovary through a long tube called the style.
The stigma is the structure responsible for gathering the pollen. The sticky platform is responsible for trapping the pollen grains and facilitating entry into the ovary.
There’s also a part of the stigma called the transmitting tissue. The transmitting tissue is an extracellular matrix made up of polysaccharides. It helps in the development of the pollen tube.
When the pollen grains germinate, they form a pollen tube and start heading for the ovary.
#5 Style
It’s a filamentous and slender structure that serves as a gateway from the stigma to the ovary. This tube-like structure takes the pollen to the ovary by acting as a transmitting passage.
At the end of the style, the ovary is attached to the thalamus ready to begin the fertilization process.
#6 Ovary
A lot of flowers have several ovaries. However, that’s not the case with hibiscuses. There’s only one ovary in the hibiscus; it’s called the superior ovary because it’s not located above the petals and not below them.
The ovary is where fertilization takes place. The pollen meets with the eggs (ovules) and forms a seed. The ovary, on the other hand, develops into the fruit after double fertilization.
The wall of the ovary turns into the pericarp, which is referred to as the fruit tissue.
#7 Male Organs (Stamen)
The male reproductive organs in the hibiscus are collectively called the stamen. The stamen is responsible for pollen production.
Most flowers have a few stamens but the hibiscus contains hundreds of stamens. The stamen contains two structures: the anthers and the filaments.
#8 Anthers
The anther is a knob-like structure that contains pollen grains (male gametes). There are microstructures within the anther, called microsporangia, that carry the pollen grains.
On the base of the stamens, there are nectaries that offer food for the pollinators.
Under a microscope, you could see that the anther of the hibiscus consists of four chambers and two lobes. The lobes are separated by a connective tissue called the parenchymatous. The chambers are separated by grooves called the strontium.
Finally, there are three layers of cells in each lobe of the anther:
- Inner tapetum. These are pyramid-shaped cells that surround the microsporangium. They help provide nutrients to the sporogenous cells
- Middle layer. Consists of one to three layers of parenchymatous cells
- Outer endothecium. They’re flattened cells that come from the mitosis of the parietal cell
In short, the role of the anther is simple: develop the flower through fertilization.
#9 Filaments
The filaments are long stalks that have the anther on the top. In the hibiscus, the filaments come from the peduncle of the thalamus and surround the style, while the stigma is found above the anthers.
There are multiple anthers sticking out of each filament. In a single hibiscus flower, there are hundreds of filaments holding up several hundred anthers.
The function of the filaments is simple: hold the anther high enough for the pollinators to reach easily. This also makes it easier for the pollen to disperse by the wind.
