Chapter 5: Morphology of Flowering Plants – Study Modules with Revision Notes
CBSE Class 11 Biology Study Module – Morphology of Flowering Plants (Chapter 5) | NCERT-Based Revision Notes
Course & Examination Details
Course: CBSE Class 11 Biology
Unit: Unit II – Structural Organisation in Animals and Plants
Chapter: Chapter 5 – Morphology of Flowering Plants
Prescribed By: CBSE Board (NCERT Syllabus)
Assessment Focus:
- Diagrams and labelling
- Botanical terminology
- Identification of plant parts
- Floral formula and floral diagrams
Chapter Overview
The study of Morphology of Flowering Plants deals with the external structure of angiosperms and helps students understand how different plant parts are adapted for specific functions. This chapter forms the foundation for taxonomy, plant physiology, ecology, and practical botany, making it extremely important for both school examinations and competitive biology exams.
The chapter primarily focuses on:
- Vegetative parts (root, stem, leaf)
- Reproductive structures (flower, fruit, seed)
- Inflorescence patterns
- Floral formula and floral diagrams
SECTION 1: Root
Definition
The root is the underground part of the plant axis that develops from the radicle of the embryo.
Functions of Root
- Anchorage of the plant
- Absorption of water and minerals
- Storage of food (in some plants)
- Synthesis of plant growth regulators
- Vegetative propagation (in certain species)
Types of Root Systems
1. Tap Root System
- Develops from the radicle
- Consists of one main root with lateral branches
- Common in dicot plants
Examples: Mustard, pea
Modification – Storage Tap Roots
- Conical (Carrot)
- Fusiform (Radish)
- Napiform (Turnip)
2. Fibrous Root System
- Radicle is short-lived
- Numerous roots arise from the base of the stem
- Common in monocots
Examples: Wheat, rice, grasses
3. Adventitious Roots
- Arise from stem or leaves
- Seen in climbers and plants with special adaptations
Examples: Banyan (prop roots), Maize (stilt roots)
Modifications of Roots
- For storage: Sweet potato
- For respiration: Pneumatophores (mangroves)
- For support: Prop roots, stilt roots
- For parasitism: Haustorial roots (Cuscuta)
SECTION 2: Stem
Definition
The stem is the ascending part of the plant axis, bearing branches, leaves, flowers, and fruits.
Functions of Stem
- Support to aerial parts
- Conduction of water, minerals, and food
- Storage of food
- Vegetative propagation
- Photosynthesis (in some plants)
Types of Stem Based on Growth
- Aerial stem: Common above-ground stem
- Subaerial stem: Runner, stolon, sucker
- Underground stem: Rhizome, tuber, bulb, corm
Modifications of Stem
1. Underground Stem Modifications
- Rhizome: Ginger
- Tuber: Potato (eyes are nodes)
- Bulb: Onion
- Corm: Colocasia
Functions: Storage, perennation, vegetative propagation
2. Aerial Stem Modifications
- Tendrils: Support (cucurbits)
- Thorns: Protection (Bougainvillea)
- Phylloclade: Photosynthesis (Opuntia)
3. Subaerial Stem Modifications
- Runner: Lawn grass
- Stolon: Strawberry
- Sucker: Mint
- Offset: Pistia
SECTION 3: Leaf
Definition
A leaf is a lateral, flattened structure borne on the stem, mainly responsible for photosynthesis.
Parts of a Leaf
- Leaf base
- Petiole
- Lamina (leaf blade)
Venation
- Reticulate venation: Dicots
- Parallel venation: Monocots
Types of Leaves
1. Simple Leaf
- Single lamina
- Incisions do not reach midrib
Example: Mango
2. Compound Leaf
- Lamina divided into leaflets
Types:
- Pinnately compound (Neem)
- Palmately compound (Silk cotton)
Phyllotaxy (Arrangement of Leaves)
- Alternate: Sunflower
- Opposite: Calotropis
- Whorled: Alstonia
Modifications of Leaves
- Tendrils: Pea
- Spines: Cactus
- Storage leaves: Onion
- Insectivorous leaves: Pitcher plant
SECTION 4: Inflorescence
Definition
Inflorescence refers to the arrangement of flowers on the floral axis.
Types of Inflorescence
1. Racemose Inflorescence
- Main axis continues to grow
- Flowers arranged in acropetal succession
Examples: Mustard, radish
2. Cymose Inflorescence
- Main axis terminates in a flower
- Flowers arranged in basipetal succession
Examples: Jasmine, bougainvillea
Special Types of Inflorescence
- Cyathium: Euphorbia
- Hypanthodium: Ficus
- Verticillaster: Ocimum
SECTION 5: Flower
Definition
The flower is the reproductive part of angiosperms, meant for sexual reproduction.
Parts of a Typical Flower
- Calyx (Sepals)
- Corolla (Petals)
- Androecium (Stamens)
- Gynoecium (Carpels)
Based on Sexuality
- Bisexual: Mustard
- Unisexual: Papaya
Based on Symmetry
- Actinomorphic: Radial symmetry
- Zygomorphic: Bilateral symmetry
- Asymmetric: No symmetry
Based on Ovary Position
- Hypogynous: Superior ovary
- Perigynous: Half-inferior ovary
- Epigynous: Inferior ovary
SECTION 6: Fruit
Definition
A fruit develops from the ovary after fertilisation.
Types of Fruits
1. Simple Fruits
- Dry fruits: Legume, capsule
- Fleshy fruits: Berry, drupe
2. Aggregate Fruits
- Develop from multicarpellary apocarpous ovary
- Example: Strawberry
3. Multiple Fruits
- Develop from inflorescence
- Example: Pineapple
Functions of Fruit
- Protection of seeds
- Seed dispersal
SECTION 7: Seed
Definition
A seed is a fertilised ovule containing an embryo.
Structure of Seed
- Seed coat
- Embryo
- Endosperm (in some seeds)
Types of Seeds
- Albuminous: Endosperm present (Maize)
- Exalbuminous: Endosperm absent (Pea)
Functions of Seed
- Propagation
- Storage of food
- Perennation
SECTION 8: Floral Formula and Floral Diagrams
Floral Formula
A symbolic representation showing:
- Symmetry
- Sex
- Number of floral parts
- Fusion of parts
- Ovary position
Common Symbols Used
- ⊕ : Actinomorphic
- ⚥ : Bisexual
- K, C, A, G : Calyx, Corolla, Androecium, Gynoecium
- Overline/underline: Ovary position
Floral Diagram
A diagrammatic representation showing:
- Arrangement of floral parts
- Position of ovary
- Number and fusion of parts
REVISION NOTES – QUICK RECAP
- Morphology studies external structure
- Root types help in identification of monocots and dicots
- Stem modifications are key exam favourites
- Leaf venation is a classification tool
- Inflorescence type helps in plant family identification
- Flower structure is central to taxonomy
- Fruit type depends on ovary nature
- Floral formula saves time in diagram-based questions
Exam-Oriented Tip
This chapter is highly scoring if terminology is precise and diagrams are well-labelled. Most CBSE questions are direct NCERT-based, making line-by-line preparation extremely effective.