The Flower: Pedicle, Parts of Flower, General Classifications, Practice Problems and FAQs

You all like flowers. They are the ornaments of the plant. Do all flowers look the same? You all have seen broccoli. Is it a flower or vegetable? Do you know the answer? Yes it is a flower but we are using it as a vegetable. 

Some plants like orchids, which produce beautiful flowers, do not need soil to grow as they get all of their nutrients from the air. Some plants, like sunflowers, produce toxic substances which kill other plants around them. Certain carnivorous plants have flowers that eat bugs and small animals! You are surprised now. Poor insects, frogs, and other small creatures are attracted towards the nectar and bright colours of flowers. Why do they need to attract these small creatures then? 

The flower is the reproductive unit in the angiosperms. It is a unique feature of all angiosperms that facilitate sexual reproduction in them. You know plants are also classified into different categories depending on floral attributes. Let’s take a deep dive into the details of floral parts and understand more about them in this article.

Fig: Flower

Table of contents

• Flower
• Pedicel
• Parts of flower
• General classifications of flowers
• Practise Problems
• FAQs

Flower

A flower is a modified shoot where the internodes are condensed and the number of appendages arising from the node are more numerous. 

Pedicel

Flowers are connected to the main stem by a stalk called pedicel. The stalk which connects the single flower to the inflorescence is also called pedicel.

Fig: Pedicel

Classification of flowers based on the presence of pedicel

Flowers are classified into two types based on the presence of pedicel as follows: 

• Pedicellate
• Sessile

Pedicellate

These are the flowers, in which a pedicel is present. Examples include Hibiscus. 

Fig: Pedicellate flower

Sessile

These are the flowers in which the pedicel is absent and flowers are directly borne on the stem. Examples include saffron flowers. 

Fig: Sessile Flower

Parts of flower

A typical flower has four different kinds of whorls arranged successively on the thalamus.

Floral parts other than floral whorls

A flower has the following parts:

• Mother axis
• Thalamus
• Bracts
• Spathe
• Bracteoles

Mother axis

It is considered as the axis on which a flower is borne. 

Thalamus

The swollen part of the flower occurring just above the pedicel is called thalamus. It is also known as a receptacle which bears floral whorls.

Fig: Flower

Bracts

Bracts are green leaf-like structures occurring at the base of the pedicel. They protect the flowers. 

Classification of flowers based on the presence of bracts:

Flowers are classified into two types based on the presence of bracts as follows: 

Spathe

Modified bracts of certain flowers which are usually enlarged and colourful to attract pollinators are called spathe.

Fig: Spathe in Bougainvillaea

Bracteoles

These are two small green leaf-like structures that are present on the pedicel of some flowers. Examples include Delphinium.

Floral whorls

Whorl is a term used for the arrangement of sepals, petals, stamens, or carpels, which radiate from a common point surrounding the stem or stalk. These are modified leaves. A typical flower has four different kinds of whorls as follows:

Calyx 

It is the whorl of sepals. It is normally green colured and protects the flower in bud condition. It is a non essential whorl. 

Corolla 

It is the whorl of petals. It is normally coloured other than green. It is a non essential whorl. They help in attracting the pollinators. 

Androecium 

It is a whorl of stamens or microsporophylls. It is an essential whorl and acts as the male reproductive part of the flower.

Gynoecium 

It is the whorl of pistils or megasporophylls. It is an essential whorl and acts as the female reproductive part of the flower. 

Fig: Floral whorls

Classification of whorls based on their functions

Non-essential whorls

These are not directly involved in sexual reproduction of plants. However, these parts may participate in attracting the pollinators or protecting the reproductive structures. It includes calyx and corolla. 

Essential whorls

These are directly involved in sexual reproduction. They include androecium and gynoecium. 

Classification of flowers based on the number of floral appendages:

A flower has some basic number of floral appendages. This is called isomery. Depending on the number of floral appendages they are of three types as follows:

General classifications of flowers

Flowers are classified into different types based on the following characteristics:

• Based on whorls
• Based on sexuality of flower
• Based on floral symmetry

Classification based on whorls

Based on the presence or absence of floral whorls, flowers can be classified into the following types:

Classification based on sexuality of flower

Based on the presence of male and female reproductive parts, flowers can be classified as follows:

Neuter flower

It is the flower in which both the essential organs like androecium and gynoecium are absent. 

Polygamous plants

In certain plants intersexual, staminate and neutral flowers occur together. These plants are called polygamous plants. 

Classification based on size of the appendages

Flowers can be of two types based on the size, shape, origin and colour of the floral appendages as follows: 

Regular flower

A flower is said to be regular when the floral parts of each whorl are similar in size, shape, origin and colour. Examples include roses. 

Fig: Regular flower 

Irregular flower

A flower is said to be irregular when the floral parts of each whorl are dissimilar in size, origin, shape or colour. Examples include pea flowers. 

Fig: Irregular flower

Classification based on floral symmetry

The arrangement of the different floral parts around the axis of the flower is called floral symmetry. Using this property flowers can be divided into equal halves. Based on the types of symmetry, flowers are classified into the following types:

Fig: Classification based on floral symmetry

Practice Problems

Q1. Radial symmetry is present in which flower?

A. Cassia
B. Brassica
C. Trifolium
D. Pisum

Solution: If a flower is divided into two equal halves by cutting in any plane passing through the centre then it is called radially symmetrical. Examples include Brassica. It is a genus of mustard family. Other examples are Datura and chilli. Hence option b is correct.

Q2. Flowers are zygomorphic in __________________.

A. Mustard
B. Tomato
C. Gulmohur
D. Datura

Solution: Zygomorphicflowers are the flowers that can be cut in only one plane to get equal halves. They are represented as % . Flowers of gulmohur have bilateral symmetry. So, they are called zygomorphic. Hence option c is correct. 

Q3. Select the incorrect statement with respect to the formation of flowers among the following?

A. The axis gets condensed and internodes do not elongate 
B. A specialised reproductive shoot
C. Floral appendages arise from internodes
D. Shoot apical meristem changes to floral meristem

Solution: Shoot has nodes and internodes. Leaves arise from the nodes. The region between nodes is considered an internode. The region in the growing shoot containing meristematic cells is known as the shoot apical meristem. During the process of flower formation, the apical meristem present in the shoot region changes into the floral meristem. When this shoot gets modified into a flower, the various floral appendages like sepals, petals, carpels and stamens, arise from the nodes instead of leaves. The internodes are usually elongated in a shoot but they will not elongate normally during flower formation. In fact, the axis gets condensed. Hence, all the floral appendages seem to arise from a common point. Hence option c is correct. 

Q4. The term perianth is used when ___________________.

A. androecium and calyx are not distinguishable 
B. corolla and gynoecium are not distinguishable
C. androecium and gynoecium are not distinguishable 
D. calyx and corolla are not distinguishable 

Solution: If there is no distinction between calyx and corolla then it is called perianth. Perianth is the collective name of the non-essential floral organ called tepal. Examples include Lilium, tulip etc. Hence option d is correct. 

Q5. What is whorl? Classify it on the basis of their function?
Answer: Whorl is a term used for the arrangement of sepals, petals, stamens, or carpels, which radiate from a common point surrounding the stem or stalk. A typical flower has four different kinds of whorls as follows: 

• Calyx - Whorl of sepals
• Corolla - Whorl of petals
• Androecium - Whorl of stamens
• Gynoecium - Whorl of pistils 

On the basis of function whorl is classified as follows: 

• Non-essential whorls: These are not directly involved in sexual reproduction of plants. However, these parts may participate in attracting the pollinators or protecting the reproductive structures. Examples include calyx and corolla. 
• Essential whorls: These are directly involved in sexual reproduction. Examples include androecium and gynoecium.

Q6. Classify flowers based on their sexuality?
Answer: Based on the presence of male and female reproductive parts, flowers can be classified as unisexual and bisexual. Unisexual flowers have either male reproductive part (androecium) or female reproductive part (gynoecium). Flowers having only androecium are called staminate flowers. Flowers having only gynoecium are called pistillate flowers. Plants bearing unisexual flowers can be monoecious (staminate and pistillate flowers occur in the same plant) or dioecious (unisexual). Examples include papaya, watermelon etc. Bisexual flowers have both the male and female reproductive parts (androecium and gynoecium). Plants bearing bisexual flowers are called monoecious plants. Examples include Hibiscus, pea etc.

Q7.  What are Bracts? Classify the flower based on the presence of bracts?
Answer: Bracts are green leaf-like structures occurring at the base of the pedicel. They protect the flowers. Based on the presence of bracts, flowers are classified as bracteate and ebracteate. Bracteate flowers are those in which bracts are present. It is represented by Br. Examples include tulips. Ebracteate flowers are those in which bracts are absent. It is represented by Ebr. Examples include mustard flowers.

Q8. What is peduncle?
Answer: The stalk of an inflorescence is called a peduncle. It bears many stalks called pedicels bearing flowers. The stalk of a single flower is called a pedicel.

FAQs

Q1. Which is considered as the tallest flower?
Answer: Amorphophallus titanum is considered as the tallest flower. It is present in the rainforests of Sumatra. It is about 3 m tall. 

Q2. Why are some plants considered as nocturnal?
Answer: Many species of plants bloom at night, they are considered as nocturnal. It may be a response to aridity to prevent excessive water loss as flowering is a water-demanding process, or to protect the pollen grain from heat stress. Examples include Epiphyllum oxypetalum or Nishagandhi. 

Q3. What is called a false flower?
Answer: A pseudanthium is considered as an inflorescence that resembles a flower. This word is used for representing other structures of plants that are neither a true flower nor a true inflorescence.

Q4. Which is considered as the first flower on the planet Earth?
Answer: An ancient plant in Liaoning, Archaefructus, had very small and simple flowers. This is considered as the first flowering plant. It lived around 130 million years ago.

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