Corolla of Flower

Introduction to Flower

Angiosperms are known for having flowers as their primary reproductive component. The term “flower,” as it is commonly used, refers mainly to reproductive structures that are colourful and distinctive in shape.

Flowers display an endless diversity of combinations in their array of colour, form, size, and anatomical arrangement. They come in various sizes, from tiny petals to large blossoms. While certain plants, like the poppy, tulip, magnolia, and petunia, produce their flowers independently and are generally large and showy, other plants, like asters, snapdragons, and lilacs, produce their flowers in characteristic clusters called inflorescences that are often relatively small. All flowers, regardless of variation, have the same purpose: to enable seed development, which facilitates species reproduction.

Plants reproduce through their flowers. They offer an abundant source of nectar. Flowers play a role in reproduction and serve as a food source for other life forms.

Flowers can either be complete or incomplete. A flower is said to be complete when it has sepals, petals, stamens, and pistils. On the other hand, a flower that lacks one or more of these features is said to be incomplete.

Table of Contents

• Parts of a Flower
• Corolla of Flower
  • Meaning of Corolla
  • Features of Corolla of Flower
  • Variations (Forms) of Corolla
  • Functions of Corolla
• Conclusion
• Frequently Asked Questions (FAQs)

Parts of a Flower

Plants are primarily divided into flowering and non-flowering classes based on whether they have flowers. A flower, a defining feature of flowering plants, is essentially an extension of the shoot used for reproduction.

The four primary components of most flowers are sepals, petals, stamens, and carpels. The female component of the flower is the carpels, while the male component is the stamens. Most flowers are hermaphrodites, meaning they have both male and female components. Others may be male or female and contain one of the two parts.

• Peduncle: The flower’s stalk is known as a peduncle.
• Receptacle: This is the area of the flower where the stalk is attached. It is tiny and is located at the centre of the flower’s base.
• Petals: This layer is located right above the sepal layer. The collection of petals is known as the corolla. Since their primary function is to draw pollinators, such as insects, butterflies, and other creatures, to the flower, they are often brightly coloured.
• Sepals: At the base of the petals, they are tiny, leaf-like components. They constitute the top whorl of the flower. Sepals are collectively referred to as the calyx. The primary purpose of the calyx and its sepals is to safeguard the flower before blooming (in the bud phase).
• Stamens: They are the male components of a flower. The androecium is a collection of many stamens. They are structurally separated into two parts:

1. Filament: The extended, slender portion that connects the anther to the flower is called a filament.
2. Anthers: The stamen’s head is where the pollen is produced, which is then transmitted to the pistil or other female sections of the same or different flower to induce fertilisation.

• Pistil: This constitutes the female components of a flower. The pistil consists of four parts: Style, Stigma, Ovary, and Ovules. The gynoecium is the term for a collection of pistils.

Corolla of Flower

What do you see when you first look at a flowering plant? Is it the flower, the stem, or the leaves? The brightly coloured petals of the flower are the most prominent part of most flowering plants. The corolla is the collective term for the arrangement of petals of flowers, which are frequently placed in a circle around the flower’s centre.

Most flowers include sepals, or little leaf-like structures, on the outside of the corolla that surround the petals before the flower develops. Most flowers have three more circles of structures added to the corolla that make up the entire flower. The first circle of structures inside the corolla is made up of many stamens and other male reproductive elements. The female reproductive part, known as the pistil, is located in a circle at the centre of the flower.

In this article, we will learn the corolla’s meaning, features, variations, and significant functions.

Meaning of Corolla

In plants, the term “corolla” refers to a collection of petals that strongly displays colour and encircles the stamen and carpel, the reproductive organs of a flower. Therefore, corolla or petals refers to the second whorl of a flower, which is internal to the calyx. Corollas can also be gamopetalous (fused) and polypetalous (free), just like the calyx.

Plants have a wide range of corolla shapes and colours. Corolla might be wheel-shaped, bell-shaped, tubular, or styled like a funnel. These corollas draw insects to the flower, and while at the flower, these insects participate in pollination.

Features of Corolla of Flower

• The important function of petals is to keep the vital flower components in their younger state.
• Due to the presence of specific pigments such as water-soluble anthocyanin, anthoxanthin, carotenoids, etc., corolla typically has a vibrant colour.
• The essential oil gives the petals their fragrance.
• Additionally, the petals have organs called nectaries that produce sugar-rich nectar to attract insects.
• Sepaloid has petals that are pale or green in colour. Examples are the Polyalthia and Annona species.
• The petals can occasionally be thicker while often being thin.
• The petal structure consists of two parts: the claw and the limb.
• The claw is the thin, stalk-like basal portion of a petal. All clawless bracts are sessile.
• A limb is the enlarged apex of the petals.
• Petals can have regular or irregular sizes and shapes.
• The corolla can have bilateral or radial symmetry.
• The edges of a petal might be whole, serrated, split, etc., much like a leaf lamina.

Variations (Forms) of Corolla

The following corolla forms are commonly seen, depending on the cohesiveness, shape, etc.

Polypetalous or Dialypetalous:

(a) Regular Forms:

1. Cruciform: In this form, as in the Cruciferae family, such as mustard, the four free clawed petals are arranged in the shape of a cross.
2. Rosaceous: Five petals are sessile (or have tiny claws) and have outward-spreading limbs. Anterior is the odd petal. This can be found in tea and members of the Rosaceae family, such as wild roses (Thea Chinensis). Due to the reasons mentioned, most grown roses have more petals.
3. Caryophyllaceous: This has five free clawed petals with limbs positioned at right angles to the claws, similar to the Caryophyllaceae family, such as the pink flower (Dianthus).

(b)Irregular Forms:

1. Papilionaceous: These five unattached petals resemble a butterfly (papillon = butterfly). The two anterior inferior petals are often more or less connected to form a boat-shaped structure known as the carina or keel. The superior posterior petal is larger than other petals and is known as the vexillum or standard.

The carina is surrounded by two lateral petals known as alae or wings, which are surrounded by the vexillum. This is a trait of the Papilionaceae subfamily, including the pea flower.

Gamopetalous or Sympetalous:

(a) Regular Forms:

1. Tubular: The limbs do not spread, and the corolla tube is essentially cylindrical all the way around. Most Composite plants have tubular centre florets, like the disc florets on sunflowers.
2. Infundibuliform or Funnel-shaped: Datura and several other members of the Convolvulaceae family, including Ipomoea pulchella, have corollas that resemble an inverted cone or funnel.
3. Campanulate or Bell-shaped: Corolla tubes have a bell-shaped base that gradually widens upward. This can be observed in the Physalis plant, various cucurbits, and the Campanulaceae family.
4. Hypocrateriform or Salver-shaped: As observed in Vinca rosea of the Apocynaceae, the corolla tube is long and narrow, with the limb positioned at a right angle.
5. Urceolate or Urn-shaped: Similar to the Kalanchoe pinnata of Crassulaceae, the corolla tube is inflated in the middle and tapers toward the base and apex.
6. Rotate or Wheel-shaped: Here, the tube is shorter than in a hypocrateriform, and the limb is at a right angle to it, as in the Nyctanthes arbor-tristis of the Oleaceae family and the brinjal (Solarium melongena), among other plants.

(b) Irregular Forms:

1. Bilabiate or Labiate or Two-lipped: This irregular corolla is joined in a way that the limb is split into an unequal lower anterior part and an upper posterior part, which is often created by the union of three petal lobes with the mouth left gaping open.

This is a feature of the Labiatae family (like Leucas) and is also present in several related families (e.g., Hygrophila and Adhatoda of Amaranthaceae).

1. Ligulate or Strap-shaped: Five petals come together to produce a narrow tube at the base that divides on one side and flattens like a strap above, as seen in many Compositae, such as the marigold’s ray florets, where it is clear that the union of five petals creates the strap.
2. Personate or Masked: It resembles the bilabiate, but the mouth is closed since the two lips are so close together. The palate is the outward extension of the lower lip that closes the mouth. Both Antirrhinum (snapdragon) and Lindenbergia have this kind of corolla.

Functions of Corolla

Corolla performs three functional activities:

1. Pollination: The flower petals have a vibrant appearance and an aromatic fragrance that attracts everyone’s attention. Bees, birds, and other pollinating creatures thus aid in the fertilisation of flowers.

2. Storage: To draw pollinators, petals serve as storage for sugar-rich nectar.

3. Protection: The male (stamen) and female (carpel) reproductive elements of the flower, which are involved in fertilising the flower to generate fruits, are protected by the whorl of petals.

Conclusion

Thus, the group of petals collectively known as corolla is the most appealing feature of a flower due to its vibrant colours and fragrance. Although it does not directly participate in pollination, it indirectly can attract or deter specific pollinators.

Related Links:

• Write the Difference between Calyx And Corolla
• Longitudinal Section of Flower
• Floral Formula
• Types of Pollination
• Morphology of Flowering Plants
• Sexual Reproduction in Flowering Plants