Morphology of Flowering Plants — Class 11 Biology NCERT Solutions (Free)
Free step-by-step NCERT solutions for Class 11 Biology chapter "Morphology of Flowering Plants" — 8 important questions with detailed answers for CBSE board exam preparation.
TL;DR: Free step-by-step NCERT solutions for Class 11 Biology chapter "Morphology of Flowering Plants" — 8 important questions with detailed answers for CBSE…
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
NCERT Solutions for Class 11 Biology — Morphology of Flowering Plants. Step-by-step answers to all 8 textbook questions from this chapter, written for CBSE board preparation and free to use.
Morphology of Flowering Plants — All 8 Questions Solved
Q1. Define a root and state its primary functions.
A root is an underground vegetative organ that typically grows downward (positive geotropism). Primary functions:
1. Absorption of water and mineral nutrients from soil.
2. Anchoring the plant firmly in soil.
3. Storage of food reserves (in some plants like carrots).
4. Synthesis of plant hormones like cytokinins and abscisic acid.
Q2. Distinguish between taproot and fibrous root systems with examples.
Taproot system:
- One main primary root with lateral branches (secondary and tertiary roots).
- Deep penetration into soil; reaches deeper soil layers and water sources.
- Examples: Dicots like bean, pea, carrot, neem.
Fibrous root system:
- Numerous roots of similar size arising from the base of the stem.
- Shallow, spreading root system covering large soil surface area.
- Better for absorbing moisture from upper soil layers.
- Examples: Monocots like wheat, rice, maize, grass.
Q3. What are root hairs and what is their role?
Root hairs are unicellular, thin-walled extensions of epidermal cells (trichoblasts) near the root tip. They are temporary structures, usually living for a few days to weeks.
Role:
1. Dramatically increase surface area for absorption (up to 15 times more than root without hairs).
2. Absorb water and mineral nutrients from soil solution through osmosis and active transport.
3. Penetrate soil pores and establish intimate contact with soil particles.
4. The cytoplasm-rich cells are metabolically active, aiding in active nutrient uptake.
Q4. Describe the external morphology of a typical leaf including petiole, lamina, and veins.
External morphology of a typical leaf:
1. Petiole (leaf stalk): The stalk connecting leaf blade to stem; conducts water and nutrients; may have a pulvinus (joint) enabling leaf movement.
2. Lamina (leaf blade): The flattened green photosynthetic portion, typically oval or lanceolate in shape.
3. Base: The region where petiole attaches to lamina; may be cuneate, cordate, or sagittate.
4. Apex: The tip of the lamina; may be acute, obtuse, or emarginate.
5. Margin: The edge of the lamina; may be entire (smooth), serrate (toothed), or lobed.
6. Veins (vascular bundles): Networks of vascular tissue visible on leaf surface. Patterns include:
- Pinnate: Main vein with lateral branches (dicots).
- Parallel: Multiple veins running parallel (monocots).
7. Midrib: The central primary vein running from base to apex.
Q5. What is a compound leaf? How does it differ from a simple leaf?
A compound leaf is a leaf blade divided into multiple separate leaflets, each with its own petiolule (small stalk), all arising from a common petiole.
Differences from simple leaf:
Simple leaf:
- Blade is continuous, not divided into separate leaflets.
- Abscission layer (where leaf detaches) is only at the petiole base.
- Examples: Mango, guava.
Compound leaf:
- Blade divided into distinct leaflets arranged pinnately or palmately.
- Abscission layers present at both petiole and petiolule bases.
- Examples: Neem (pinnate), Horse chestnut (palmate).
Significance: Compound leaves reduce wind damage and allow better penetration of light to lower leaves.
Q6. Describe the modifications of stem and give examples (5-mark answer).
Modifications of stem are adaptations for different functions—storage, protection, photosynthesis, and support:
1. Underground modifications:
a) Rhizome: Horizontal underground stem; produces roots and aerial shoots at nodes. Example: Ginger, turmeric, banana.
b) Bulb: Underground stem with fleshy leaves storing food. Example: Onion, garlic, lily.
c) Corm: Compact underground stem swollen with stored food. Example: Colocasia, crocus.
d) Tuber: Swollen underground stem tip storing starch. Example: Potato.
2. Aerial modifications:
a) Runner: Horizontal above-ground stem rooting at nodes. Example: Strawberry.
b) Tendril: Slender, coiling stem for climbing. Example: Grape, passion fruit.
c) Spine/Thorn: Pointed modified stem for protection. Example: Citrus (thorn), Euphorbia (spine).
d) Phyllode: Flattened green stem functioning as leaf. Example: Acacia.
3. Photosynthetic modifications:
- Cladode: Flattened green stem resembling leaf. Example: Ruscus.
All modifications show adaptation to specific environmental or functional requirements.
Q7. Define venation and compare pinnate and palmate venation patterns.
Venation is the arrangement of veins (vascular bundles) in a leaf blade, visible on the leaf surface.
Pinnate venation:
- One main central vein (midrib) running from leaf base to apex.
- Lateral veins branch obliquely from midrib on both sides, resembling a feather (pinna).
- Further branching creates a network of smaller veins.
- Characteristic of dicots.
- Examples: Mango, rose, sunflower.
Palmate venation:
- Multiple primary veins of equal size radiating from the petiole base like fingers of a palm.
- No single dominant midrib.
- Veins spread out in a fan-like pattern.
- Characteristic of some dicots.
- Examples: Maple, horse chestnut, okra.
Parallel venation (for comparison):
- Multiple veins of similar size running parallel to each other from leaf base to apex.
- No net-like branching.
- Characteristic of monocots.
- Examples: Wheat, rice, grass, banana.
Q8. Describe different types of leaf arrangements (phyllotaxy) on a stem.
Phyllotaxy is the arrangement of leaves on a stem.
Main types:
1. Alternate (Alternate phyllotaxy):
- Leaves arise singly at each node, arranged alternately on opposite sides of the stem.
- One leaf per node.
- Examples: Sunflower, castor, cotton.
2. Opposite:
- Two leaves arise at each node on opposite sides of the stem, one facing the other.
- Leaves form pairs at successive nodes.
- Examples: Mint, tulsi, Calotropis.
3. Whorled:
- Three or more leaves arise at the same node around the stem.
- Arranged in a circle at each node.
- Examples: Nerium (4 leaves), Alstonia (whorled).
Significance of phyllotaxy:
1. Exposes maximum leaf surface to sunlight, minimizing mutual shading.
2. Allows optimal penetration of light and rain to lower parts of plant.
3. Is characteristic of plant species, aiding in identification and classification.
Morphology of Flowering Plants — Practice MCQs with Answers
Attempt these 20 multiple-choice questions after working through the solutions above. Each carries the correct option and the reasoning behind it, so a wrong answer tells you which idea to revisit.
MCQ 1. Which of the following is an example of a tap root modified for storage?
- A. Sweet potato
- B. Carrot
- C. Dahlia
- D. Asparagus
Answer: B. Carrot — Carrot is a classic example of a conical tap root modified for food storage. Sweet potato and Dahlia have adventitious roots modified for storage, while Asparagus has fasciculated adventitious roots.
MCQ 2. Thorns in Bougainvillea and tendrils in Cucurbita are examples of modifications of which plant part?
- A. Root
- B. Leaf
- C. Stem
- D. Flower
Answer: C. Stem — Thorns and tendrils in these plants are modifications of the axillary bud, which develops into a stem structure for protection (thorns) or support (tendrils).
MCQ 3. Which type of venation is characteristic of dicotyledonous plants?
- A. Parallel venation
- B. Reticulate venation
- C. Both parallel and reticulate venation
- D. Absence of venation
Answer: B. Reticulate venation — Dicotyledonous plants typically exhibit reticulate venation, where veins form a network. Monocotyledonous plants generally have parallel venation.
MCQ 4. In which type of phyllotaxy do more than two leaves arise at each node and form a whorl?
- A. Alternate
- B. Opposite
- C. Whorled
- D. Spiral
Answer: C. Whorled — Whorled phyllotaxy is characterized by the arrangement where more than two leaves arise at a node and form a whorl, as seen in Alstonia and Nerium.
MCQ 5. A racemose inflorescence is characterized by:
- A. Limited growth of the main axis and terminal flower
- B. Unlimited growth of the main axis and lateral flowers
- C. Flowers developing in a basipetal succession
- D. Main axis terminating in a flower
Answer: B. Unlimited growth of the main axis and lateral flowers — In racemose inflorescence, the main axis continues to grow indefinitely, and flowers are borne laterally in an acropetal succession, meaning younger flowers are at the apex.
MCQ 6. When a flower can be divided into two equal radial halves in any radial plane passing through the centre, it is said to be:
- A. Zygomorphic
- B. Actinomorphic
- C. Asymmetric
- D. Hypogynous
Answer: B. Actinomorphic — Actinomorphic (radial symmetry) describes a flower that can be divided into two equal halves by any radial plane passing through the centre, like a star. Zygomorphic flowers have bilateral symmetry.
MCQ 7. In a flower, if the gynoecium is situated in the centre and other parts of the flower are located on the rim of the thalamus almost at the same level, the ovary is said to be:
- A. Superior
- B. Inferior
- C. Half inferior
- D. Hypogynous
Answer: C. Half inferior — This describes a perigynous flower, where the ovary is half inferior. The other floral parts are at the rim of the thalamus at the same level as the ovary.
MCQ 8. Which type of aestivation is observed in the petals of pea and bean flowers, where the largest petal (standard) overlaps the two lateral petals (wings), which in turn overlap the two smallest anterior petals (keel)?
- A. Valvate
- B. Twisted
- C. Imbricate
- D. Vexillary
Answer: D. Vexillary — This specific arrangement is called vexillary aestivation, characteristic of Fabaceae members like pea and bean. It is a specialized form of imbricate aestivation.
MCQ 9. In which type of placentation does the ovules develop on the inner wall of the ovary or on peripheral part?
- A. Marginal
- B. Axile
- C. Parietal
- D. Free central
Answer: C. Parietal — Parietal placentation is found in unilocular ovaries where ovules develop on the inner wall or peripheral part, as seen in mustard and Argemone.
MCQ 10. A fruit developed from a monocarpellary superior ovary, typically with a hard and stony endocarp, is called a:
- A. Berry
- B. Pome
- C. Drupe
- D. Capsule
Answer: C. Drupe — A drupe is a simple fleshy fruit derived from a monocarpellary superior ovary, characterized by a fleshy mesocarp and a hard, stony endocarp (e.g., mango, coconut).
MCQ 11. Which of the following is an example of an endospermic (albuminous) seed?
- A. Gram
- B. Pea
- C. Bean
- D. Castor
Answer: D. Castor — Castor is an endospermic (albuminous) seed, meaning it retains a part of the endosperm as food storage. Gram, pea, and bean are non-endospermic (exalbuminous) seeds.
MCQ 12. Pneumatophores are modified roots that help in respiration and are found in:
- A. Banyan trees
- B. Mangrove plants
- C. Sweet potato
- D. Maize
Answer: B. Mangrove plants — Pneumatophores are specialized roots that grow vertically upwards from the marshy soil to obtain oxygen for respiration, characteristic of mangrove plants like Rhizophora.
MCQ 13. In Bougainvillea, the brightly colored structures that appear like petals are actually modified leaves called:
- A. Sepals
- B. Stamens
- C. Bracts
- D. Tendrils
Answer: C. Bracts — The colorful structures surrounding the actual small flowers in Bougainvillea are bracts, which are modified leaves functioning to attract pollinators.
MCQ 14. Identify the correct match for leaf modification:
- A. Pitcher plant - Stem tendril
- B. Opuntia - Photosynthetic stem
- C. Pea - Leaf spine
- D. Australian Acacia - Phyllode
Answer: D. Australian Acacia - Phyllode — In Australian Acacia, the petiole expands, becomes green, and synthesizes food, functioning as a leaf. This modified petiole is called a phyllode.
MCQ 15. A cyme inflorescence is characterized by:
- A. Flowers arranged in an acropetal manner
- B. Indefinite growth of the main axis
- C. The main axis terminating in a flower
- D. Older flowers located at the base
Answer: C. The main axis terminating in a flower — In cymose inflorescence, the main axis terminates in a flower, hence its growth is limited. Flowers are borne in a basipetal order.
MCQ 16. The floral formula K(5)C(5)A5G(2) represents a flower with:
- A. Five free sepals, five fused petals, five free stamens, two fused carpels
- B. Five fused sepals, five free petals, five free stamens, two fused carpels
- C. Five fused sepals, five fused petals, five free stamens, two free carpels
- D. Five free sepals, five free petals, five fused stamens, two free carpels
Answer: B. Five fused sepals, five free petals, five free stamens, two fused carpels — Parentheses around a number indicate fusion. So, K(5) means five fused sepals, C(5) means five fused petals, A5 means five free stamens, and G(2) means two fused carpels.
MCQ 17. Which of the following describes the position of the ovary in mustard and china rose?
- A. Inferior
- B. Superior
- C. Half inferior
- D. Partially inferior
Answer: B. Superior — Mustard and china rose have hypogynous flowers, where the ovary is superior and the other floral parts are situated below it.
MCQ 18. The floral formula for the family Fabaceae is:
- A. % ⚥ K(5) C1+2+(2) A(9)+1 G1
- B. ⊕ ⚥ K(5) C(5) A5 G(2)
- C. Br ⚥ P3+3 A3+3 G(3)
- D. % ⚥ K(5) C5 A(10) G(1)
Answer: A. % ⚥ K(5) C1+2+(2) A(9)+1 G1 — The floral formula % ⚥ K(5) C1+2+(2) A(9)+1 G1 correctly represents Fabaceae with zygomorphic, bisexual flowers, five fused sepals, papilionaceous corolla (one standard, two wings, two fused keel petals), diadelphous stamens (9 fused, 1 free), and a monocarpellary, superior ovary.
MCQ 19. The fruit type characteristic of the family Solanaceae is typically a:
- A. Pod
- B. Drupe
- C. Berry or capsule
- D. Pome
Answer: C. Berry or capsule — Fruits in the Solanaceae family are typically a berry (e.g., tomato, brinjal) or a capsule (e.g., Datura, Petunia).
MCQ 20. Which plant family is characterized by a perianth (P) and trimerous flowers?
- A. Fabaceae
- B. Solanaceae
- C. Liliaceae
- D. Brassicaceae
Answer: C. Liliaceae — Liliaceae is a monocot family known for its trimerous flowers (floral parts in multiples of three) and a distinct perianth (undifferentiated calyx and corolla).
How to Use These Solutions
Attempt each question yourself first and only then compare with the worked answer. Marks in the CBSE board exam are awarded for the METHOD as much as the final result, so reproduce the steps rather than memorising the last line. Where a solution states a law, a formula or a definition, learn that wording — examiners look for it.
Related practice for this chapter: chapter MCQs, previous-year questions, revision notes and sample papers.