From the anchoring roots deep in the soil to the delicate petals of a flower, the external form of a plant reveals its blueprint for survival and reproduction. To truly appreciate the incredible diversity within the plant kingdom, Chapter 5 of Class 11 Biology, “Morphology of Flowering Plants,” guides students through the fascinating architecture of angiosperms, from their basic parts to their complex modifications. It explains how plants are identified and understood based on the form and features of the root, stem, leaf, inflorescence, flower, fruit, and seed, and introduces key plant families like Fabaceae, Solanaceae, and Liliaceae. This chapter is part of the comprehensive NCERT Solutions Class 11 Biology series, which covers all chapters in detail.
The NCERT Solutions for Morphology of Flowering Plants provided here offer clear, step-by-step answers to all textbook questions. These well-explained solutions make intricate topics like the modification of roots for support and storage, the different types of placentation in the ovary, and the various patterns of aestivation in flowers easier to grasp, helping students build strong conceptual understanding. They also improve answer-writing skills and support effective preparation for Class 11 exams as well as competitive exams like NEET.
NCERT Solutions for Class 11 Biology Chapter 5- All Exercise Questions
Q.
What is meant by modification of root? What type of modification of root is found in the:
(a) Banyan tree
(b) Turnip
(c) Mangrove trees
Q.
Justify the following statements on the basis of external features:
(i) Underground parts of a plant are not always roots.
(ii) Flower is a modified shoot.
Q.
How is a pinnately compound leaf different from a palmately compound leaf?
Q.
Explain with suitable examples the different types of phyllotaxy.
Q.
Define the following terms:
(a) aestivation
(b) placentation
(c) actinomorphic
(d) zygomorphic
(e) superior ovary
(f) perigynous flower
(g) epipetalous stamen
Q.
Differentiate between
(a) Racemose and cymose inflorescence
(b) Fibrous root and adventitious root
(c) Apocarpous and syncarpous ovary
Q.
Draw the labelled diagram of the following:
(i) gram seed
(ii) V.S. of maize seed
Q.
Describe modifications of stem with suitable examples.
Q.
Take one flower each of the families Fabaceae and Solanaceae and write its semi-technical description. Also draw their floral diagram after studying them.
Q.
Describe the various types of placentations found in flowering plants.
Q.
What is a flower? Describe the parts of a typical angiosperm flower.
Q.
How do the various leaf modifications help plants?
Q.
Define the term inflorescence. Explain the basis for the different types of inflorescence in flowering plants.
Q.
Write the floral formula of a actinomorphic, bisexual, hypogynous flower with five united sepals, five free petals, five free stamens and two united carpels with superior ovary and axile placentation.
Q.
Describe the arrangement of floral members in relation to their insertion on thalamus.
NCERT Solutions for Class 11 Biology Chapter 5 - Morphology of Flowering Plants
Class 11 Chapter 5 Biology Questions & Answers – The Living World
Q.1 What is meant by modification of root? What type of modification of root is found in the:
(a) Banyan tree
(b) Turnip
(c) Mangrove trees
Solution: The root performs two major functions in a plant:
- Absorption of nutrients and water from the soil for proper growth of the plants, and
- Providing mechanical support to plant by anchoring it tightly with the soil
However, in some cases, depending on the environmental conditions and physiological needs of the plants, the roots get modified to perform the functions apart from the ones mentioned above. This change in the root structure and function is known as root modification. The types of root modification in different plants/trees are listed below:
| S.No. |
Plants/trees with root modification |
Purpose of modification |
| (a) |
Banyan tree |
Support: In a banyan tree, the prop roots arise from aerial branches and provide support to the plant. |
| (b) |
Turnip |
Storage: In turnip, the roots get swollen and function as a storage organ. |
| (c) |
Mangrove tree |
Respiration: In mangrove trees which grow in marshy areas, the roots get modified to pneumatophores that help in gaseous exchange. |
Q.2Justify the following statements on the basis of external features:
(i) Underground parts of a plant are not always roots.
(ii) Flower is a modified shoot.
Solution:
(i) Underground parts of a plant are not always roots.
During the course of evolution, plants modified their external morphologies according to the environmental conditions of their ecological niches for better adaptability. There are several examples where the stem, which is generally the aerial part of a plant, gets modified in a way that it remains under the soil. Such stem modifications can easily be recognized by the presence of nodes and internodes on them. The main reason for such modifications is to protect the plant from unfavourable environmental conditions. For example, the underground part of ginger, turmeric, zaminkand, and Colocasia all have distinct node and internodes, thus they are stem modifications. Similarly, in banana, pineapple and Chrysanthemum, the stem remains underground and grows beneath the soil. In case of onion and garlic, the leaves remain underground, become fleshy, and store food. Therefore, from the above examples, it is clear that underground parts of plants are not always roots as both stem and leaves in some cases have modified themselves to grow beneath the ground.
(ii) A flower is a modified shoot.
During the flowering season, the apical shoot meristem gets transformed to floral meristem. The close anatomical study of a flower reveals the presence of nodes and internodes. The main axis gets highly condensed and the internodes do not undergo further elongation. From the apex, instead of leaves, various floral appendages such as calyx, corolla, androecium and gynoecium arise. Thus, it can be said that a flower is a modified shoot.
Q.3 How is a pinnately compound leaf different from a palmately compound leaf?
Solution:
| Pinnately compound leaf |
Palmately compound leaf |
| It is a compound leaf where leaflets are arranged like bird’s feathers on a common axis, called the rachis.
Example: Neem |
In this type of leaf, the leaflets are attached at a common point, that is, they radiate out from the tip of petiole.
Example: Silk cotton |
Q.4 Explain with suitable examples the different types of phyllotaxy.
Solution: The term phyllotaxy originated from the Greek words ‘phyllon’ which stands for “leaf” and “taxis” which stands for arrangement. Thus, the pattern of arrangement or organization of leaves on a branch or stem is called phyllotaxy.
Broadly, phyllotaxy is of three types:
(i) Alternate: When each node of the axis bears a single leaf, it is called alternate phyllotaxy. Example: China rose, mustard and sunflower plants.
(ii) Opposite: When each node of the axis bears a pair of leaf facing in the opposite direction, it is called opposite phyllotaxy. Example: Calotropis and guava plants.
(iii) Whorled: When more than two leaves arise from each node, it is called whorled phyllotaxy. Example: Alstonia.
Q.5 Define the following terms:A
(a) aestivation, (b) placentation
(c) actinomorphic, (d) zygomorphic
(e) superior ovary, (f) perigynous flower
(g) epipetalous stamen
Solution: (a) Aestivation: The positional arrangement of sepals or petals in the floral bud with respect to other sepals or petals in the same whorl is called aestivation. The four different types of aestivation are twisted, valvate, imbricate and vexillary.
(b) Placentation: The arrangement of ovules in the ovary is called placentation. Depending on the pattern of arrangement, placentation is categorized into different types, namely marginal, parietal, axile, basal, central and free central.
(c) Actinomorphic: The flowers that can be divided into equal halves in any of the radial plane passing through the centre of the flower are called actinomorphic. Thus, these flowers show radial symmetry. Example: flowers of chilli and Datura are actinomorphic.
(d) Zygomorphic: The flowers that can be divided into two equal halves only in one particular vertical plane are called zygomorphic. These flowers show bilateral symmetry. Example: flowers of Gulmohar, bean and Cassia are zygomorphic.
(e) Superior ovary: The flowers in which the gynoecium is present at the highest position, that is, above calyx, corolla and androecium, the ovary in such flowers is called the superior ovary. Example: mustard, china rose and brinjal.
(f) Perigynous flower: The flower in which the ovary (gynoecium) is located at the centre of the thalamus while other floral appendages are located at the rim of the thalamus, such flower is called perigynous flower. Example: plum, rose, and peach.
(g) Epipetalous stamen: When the stamen is connected to the petals of a flower, it is known as the epipetalous stamen. Example: Brinjal
Q.6 Differentiate between
(a) Racemose and cymose inflorescence
(b) Fibrous root and adventitious root
(c) Apocarpous and syncarpous ovary
Solution: (a)Racemose and cymose inflorescence
|
Racemose inflorescence |
Cymose inflorescence |
| 1. |
The main floral axis shows unlimited growth and the terminal flower is not formed. |
The main axis has limited growth and terminates in a flower. |
| 2. |
The inflorescence follows an acropetal order, where the flowers start maturing from the bottom of influorescence axis. |
The inflorescence follows basipetal succession and the flower at the top of axis matures first. |
(b) Fibrous root and adventitious root
|
Fibrous root |
Adventitious root |
| 1. |
When the roots arise from the base of stem by replacing the primary root, it is called fibrous root. |
When the roots arise from any part of the plant other than radicle, it is called adventitious root. They may arise from stem or leaves. |
| 2. |
These are generally short and very dense and are usually found in monocot plants. Example: maize. |
These may be very large and strong. Example: prop root of the banyan tree. |
(c) Apocarpous and syncarpous ovary
|
Apocarpous ovary |
Syncarpous ovary |
| 1. |
An apocarpous ovary is an ovary in which the carpels are free and not fused with each other. |
When a gynoecium has many carpels that are fused into a single structure, it is called the syncarpous ovary. |
| 2. |
Example: Lotus and rose. |
Example: Mustard and tomato. |
Q.7 Draw the labelled diagram of the following:
(i) gram seed, (ii) V.S. of maize seed
(ii) Vertical section (V.S.) of maize seed
Q.8 Describe modifications of stem with suitable examples.
Solution: The stem is the aerial part of a plant which originates from the plumule of the embryo and bear branches, leaves, flowers and fruits. In certain cases, it gets modified into tendrils, thorns, fleshy, or flattened structures.
The main functions of stem are as follows:
(i) It forms an axis to support the lateral branches, flower and fruits.
(ii) It conducts water and nutrients through vascular tissue.
(iii) It bears leaves.
Apart from the above-mentioned functions, the stems sometimes get structurally modified to perform the following specialized functions:
(i) Storage: In the case of potato, zaminkand, Colocasia, ginger, and turmeric the stem gets modified to form an underground structure that protects the plant from unfavourable conditions and also acts as a storage organ.
(ii) Support: In some creepers such as cucumber, pumpkin and watermelon, the stem gets modified to form a slender and spirally coiled structure, called tendril, that coils around the wall or rope and helps the plant in climbing up.
(iii) Protection: In Bougainvillea and Citrus plants, the axillary bud of stem gets modified to a straight and pointed woody structure called a thorn, which protects the plants from being eaten up by herbivorous animals.
(iv) Photosynthesis: In arid regions, to prevent high water loss through transpiration, plants modify their stem into a flattened or fleshy cylindrical structure. These structures have chlorophyll and perform photosynthesis. Examples: Opuntia and Euphorbia.
(v) Vegetative propagation: In plants like grasses and strawberry, the underground stem spreads to new niche and develops into new plants. In mint and jasmine, the lateral branches after growing for certain length, arch down to the ground and form a new plant. In some aquatic plants like Pistia and Eichhornia, each node bears the rosette of leaves and tuft of roots, which give rise to a new plant once it gets detached from the parent plant.
Q.9 Take one flower each of the families Fabaceae and Solanaceae and write its semi-technical description. Also draw their floral diagram after studying them.
Solution:
|
Fabaceae |
Solanaceae |
| Name of Plant |
Pea plant (Pisum sativum) |
Makoi plant (Solanum nigrum) |
| Vegetative Characters |
Herbaceous climber |
Annual herb |
| Root |
Contains root nodules |
Tap root without nodules |
| Stem |
Erect, branched, solid, possesses tendrils |
Herbaceous, erect, smooth and branched |
| Leaves |
Alternate, pinnately compound, reticulate venation, pulvinate base, terminal leaflet modifies into tendrils |
Alternate, simple, estipulate with reticulate venation |
| Inflorescence |
Racemose |
Cymose |
| Flower |
Bisexual, zygomorphic |
Bisexual, actinomorphic |
| Calyx |
Five sepals, gamosepalous; imbricate aestivation |
Five sepals, united, persistent; valvate aestivation |
| Corolla |
Five petals, polypetalous, vexillary aestivation |
Five petals, united, valvate aestivation |
| Androecium |
Ten stamens, diadelphous, anther dithecous |
Five epipetalous stamens |
| Gynoecium |
Superior ovary, mono carpellary, unilocular with many ovules, single style |
Bicarpellary, syncarpous, superior ovary, bilocular, swollen placenta with many ovules. |
| Fruits |
Legume |
Berry |
| Seeds |
Several, non-endospermic |
Many, endospermic |
| Floral diagram
|
|
|
Q.10 Describe the various types of placentations found in flowering plants.
Solution: The arrangement of ovules in the ovary is called placentation. Depending on the mode of arrangement, placentation is of following types:
- Marginal placentation: It is observed in the flowers where gynoecium is monocarpellary, apocarpous and unilocular as in pea. At the ventral surface of the ovary, a ridge is formed by the placenta and ovules are borne in the ridge.
- Axile placentation: It is observed when gynoecium is multicarpellary, syncarpous and multilocular. Here, the placenta is axial and ovules are attached to it in the multilocular ovary. Example: China rose, tomato and lemon.
- Parietal placentation: It is observed when gynoecium is multicarpellary, syncarpous and unilocular. Here, ovules develop on the periphery of the ovary. Example: mustard and Argemone.
- Free central placentation: In this, the gynoecium is multicarpellary, syncarpous and unilocular and the ovules are borne on the central axis without any septa. Example: Dianthus and Primrose.
- Basal placentation: In this, the gynoecium is unilocular with placenta developing at the base of the ovary and single ovule attaches to it. Example: Sunflower and marigold.
Q.11 What is a flower? Describe the parts of a typical angiosperm flower.
Solution: The reproductive unit of the angiosperm plant, bearing male or female or both reproductive parts that are responsible for sexual reproduction is called flower. A flower is a modified stem with a highly condensed axis.
A typical angiosperm flower consists of four whorls, namely calyx, corolla, androecium and gynoecium. The flower, having all these four whorls, is known as a complete flower. The complete flower is a bisexual flower as both male and female gamete forming organs are present in it. The various parts of a typical angiosperm flower are described below:
(i) Calyx: It is the outermost whorl of the flower. It consists of individual units called sepals. Generally, sepals are green in colour. Its main function is to protect the bud of the plant from adverse environmental conditions. If the sepals are free, it is called polysepalous but sometimes sepals are fused giving rise to the gamosepalous condition.
(ii) Corolla: Next to calyx is corolla, which consists of individual petals. Petals are beautiful coloured structures that play a key role in attracting insects to increase the chances of pollination.
(iii) Androecium: The male gamete producing part of the plant is called androecium. Its individual units are called the stamen. An individual stamen consists of filament and anther.
(iv) Gynoecium: It is the female reproductive organ of a plant. It consists of carpels. Each carpel is made up of three parts, namely; ovary, style and stigma.
Q.12 How do the various leaf modifications help plants?
Solution: Leaves are the photosynthetic sites of the plant; however, in some cases, they get modified to provide support, protection, storage or nutrients to the plants.
- Support: In case of plants like pea, the leaves get converted to a spiral structure called tendrils that help the plant to climb up on the support structure like a wall.
- Protection: In cactus, the leaves get reduced to spines to protect the plant from animals as well as to reduce water loss through stomata.
- Storage: The fleshy underground leaves of garlic and onion help in the storage of food and ensure the survival of plant under unfavourable conditions.
- Nutrients: In the carnivorous plants such as venus-fly trap that grows in the nitrogen-deficient soil, the leaves get modified into a pitcher to capture the insect and thus provide required nutrients to the plant.
Q.13 Define the term inflorescence. Explain the basis for the different types of inflorescence in flowering plants.
Solution: The arrangement of flowers on the floral axis is called inflorescence.
During the flowering season of a fully developed plant, the apical meristem gives rise to floral meristem which in turn develops the floral axis. Floral axis contains laterally developed flowers. On the basis of the type of growth of the floral axis, the inflorescence is of two types:
(i) Cymose inflorescence or determinate inflorescence: When the main axis terminates in a flower, it is known as cymose inflorescence. This type of inflorescence limits the growth.
(ii) Racemose or indeterminate inflorescence: When the main axis keeps on growing without terminating in a flower bud, it is known as racemose inflorescence.
Q.14 Write the floral formula of an actinomorphic, bisexual, hypogynous flower with five united sepals, five free petals, five free stamens and two united carpels with superior ovary and axile placentation.
Solution:
| Terms |
Symbol used in the floral formula
|
|
Actinomorphic
|
|
|
Bisexual
|
|
|
Five united sepals
|
K(5)
|
|
Five free petals
|
C5
|
|
Five free stamens
|
A5
|
|
Two united carpels with superior ovary and axile placentation
|
G(2)
|
Q.15 Describe the arrangement of floral members in relation to their insertion on thalamus.
Solution: The floral appendages are arranged on the thalamus. On the basis of the location of the ovary with respect to other floral appendages (calyx, corolla and androecium), the flower can be broadly classified into three categories:
(a) Hypogynous flower: In some plants like mustard, china rose and brinjal, gynoecium occupies the highest position compared to calyx, corolla and androecium. Such flowers are called hypogynous flowers. Here, the ovary is located at the uppermost part of the thalamus. Such an ovary is called the superior ovary.
(b) Perigynous flower: In the flowers like rose, the gynoecium is at the centre of the thalamus and other floral whorls are at the rim of the thalamus with ovary situated at the same level. Such flowers are called perigynous flowers.
(c) Epigynous flower: In the flowers like guava, the margin of thalamus completely covers the ovary and other floral whorls arise above the ovary. Such flowers are called epigynous flowers.
More Resources of NCERT Solutions for Class 11 Biology
NCERT Solutions for Class 11 Biology Chapter 5 – FAQs
Q1. How can I tell if an underground part is a root or a modified stem?This is one of the most common confusions! Look for these key features:Modified Stems have:Clear nodes and internodes (visible as rings or lines on the surface)
- Buds or scale leaves present at nodes (like “eyes” on potato)
- May have adventitious roots arising from nodes
- Internal structure resembles aerial stem, not root
- Examples: Potato (tuber), ginger (rhizome), turmeric (rhizome), onion (bulb)
Roots have:
- No nodes or internodes
- Root cap at the tip
- Root hairs for absorption
- No buds or scale leaves
- Examples: Carrot, radish, sweet potato (all are modified roots for storage)
Quick Tip: If you can see “eyes” or nodes, it’s a stem! Underground stems like potato tubers have eyes (buds at nodes), while roots like carrots don’t.
Q2. What’s the difference between the different types of placentation, and how do I remember them?
Placentation is the arrangement of ovules inside the ovary. Here are the main types with easy memory tricks:
| Type |
Where are ovules? |
Example |
Memory Trick |
| Type |
Where are ovules? |
Ovary type |
Example |
|
|
|
|
| Marginal |
On ridge along ventral suture in two rows |
Monocarpellary, unilocular |
Pea, beans |
| Axile |
On central axis where carpel margins meet |
Multicarpellary, syncarpous, multilocular |
Tomato, lemon, China rose, lily |
| Parietal |
On inner ovary wall or periphery |
Syncarpous, unilocular (may have false septum) |
Mustard, cucumber, Argemone |
| Free Central |
On central axis without septa |
Syncarpous, unilocular, no septa |
Dianthus, Primrose |
| Basal |
At the base, typically single ovule |
Unilocular |
Sunflower, marigold |
Study Tip: Draw cross-sections! Visual memory works best for placentation. Always draw and label the ovary position and ovule arrangement.
Q3. What are the key differences between Hypogynous, Perigynous, and Epigynous flowers?
These terms describe the position of the ovary relative to other flower parts. Think of it as “where does the ovary sit?”
| Feature |
Hypogynous |
Perigynous |
Epigynous |
| Meaning |
“Below the ovary” |
“Around the ovary” |
“Upon the ovary” |
| Ovary position |
Superior (above other parts) |
Half inferior (at same level) |
Inferior (below other parts, enclosed by thalamus) |
| Thalamus/receptacle |
Convex or flat |
Flattened or slightly concave (cup-shaped) |
Completely encloses ovary |
| Other floral parts |
Inserted below the ovary |
Inserted around ovary at rim of thalamus |
Inserted above the ovary |
| Examples |
Mustard, China rose, brinjal |
Rose, peach, plum |
Guava, cucumber, apple, sunflower |
Memory Trick:
- Hypo (like hypodermic = below skin) = parts below ovary
- Peri (like perimeter = around) = parts around ovary
- Epi (like epidermis = upon skin) = parts upon ovary
Visual Tip: In hypogynous, the ovary sits on top like a crown . In epigynous, the ovary is buried at the base and other parts sit on top of it.
Q4. How do I write and understand floral formulas?
A floral formula is like a shorthand code for describing a flower. Here’s how to decode it:
Symbols Used:
- ⚲ = Actinomorphic (radial symmetry)
- % = Zygomorphic (bilateral symmetry)
- ⚥ = Bisexual
- ♂ = Male flower
- ♀ = Female flower
- K = Calyx (sepals)
- C = Corolla (petals)
- A = Androecium (stamens)
- G = Gynoecium (carpels)
- ( ) = Fused/united parts
- Numbers = Number of parts
- G̅ (line above) = Inferior ovary
- G (line below) = Superior ovary
Example 1: Mustard
⚲ ⚥ K4 C4 A2+4 G(2)
Reading: Actinomorphic, bisexual flower with 4 sepals, 4 petals, 6 stamens (2+4 arrangement), 2 fused carpels with superior ovary
Example 2: Pea (Fabaceae)
% ⚥ K(5) C5 A(9)+1 G1
Reading: Zygomorphic, bisexual flower with 5 fused sepals, 5 free petals, 10 stamens (9 fused + 1 free = diadelphous), 1 carpel with superior ovary
Practice Tip:
- Start from outside to inside: Calyx → Corolla → Androecium → Gynoecium
- Look for brackets (fusion)
- Check ovary position (line position on G)
- Practice with common families: Fabaceae, Solanaceae, Liliaceae
Common Exam Question: Write floral formula for a given flower description or draw the flower from a given formula!