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Morphology of Flowering Plants – Class 11 Biology notes, important questions and MCQs

NCERT Class 11 Biology, chapter 5. Notes, key terms, important questions with answers and MCQs.

Chapter overview

Morphology studies the external form of plants: root, stem, leaf, inflorescence, flower, fruit and seed, and their modifications.

Vegetative parts

Roots: tap root (dicots), fibrous (monocots), adventitious; modifications for storage (carrot), support (prop roots of banyan) and respiration (pneumatophores).
Stems: nodes and internodes; modifications include tubers (potato), rhizomes (ginger), tendrils, thorns.
Leaves: venation reticulate (dicots) or parallel (monocots); phyllotaxy alternate, opposite, whorled.

Reproductive parts

Inflorescence: racemose (main axis keeps growing) and cymose (main axis ends in a flower).
Flower parts: calyx, corolla, androecium, gynoecium; ovary superior (hypogynous) or inferior (epigynous); placentation types.
Fruits develop from the ovary; seeds: dicot (two cotyledons) and monocot (one cotyledon, scutellum).

Key terms

Placentation: arrangement of ovules within the ovary
Inflorescence: arrangement of flowers on the floral axis
Aestivation: arrangement of sepals or petals in a flower bud relative to each other (valvate, twisted, imbricate, vexillary)

Important questions with answers

What is the difference between a tap root and an adventitious root?2 marks

A tap root develops from the radicle and has a main root with branches (mustard). Adventitious roots arise from parts other than the radicle, such as stem nodes (banyan prop roots, grass).

Describe three types of placentation with one example each.3 marks

Marginal: ovules on a ridge along one side of a single-chambered ovary (pea). Axile: ovules on a central axis in a multi-chambered ovary (china rose, tomato, lemon). Parietal: ovules on the inner wall of a one-chambered ovary (mustard, Argemone). (Also free central – Dianthus; basal – sunflower.)

Describe the floral characters of the family Fabaceae and write its floral formula and two economic uses.5 marks

Fabaceae (pea family): leaves pinnately compound with pulvinus; flowers bisexual and zygomorphic. Calyx: 5 sepals, gamosepalous. Corolla: 5 petals, papilionaceous — one large standard (vexillum), two wings (alae) and two fused keel petals (carina), vexillary aestivation. Androecium: 10 stamens, diadelphous (9 + 1). Gynoecium: superior, monocarpellary, unilocular ovary with marginal placentation. Fruit: legume (pod). Floral formula: % ⚥ K₍₅₎ C₁₊₂₊₍₂₎ A₍₉₎₊₁ G₁. Uses: pulses (gram, arhar, soybean) and edible oil (groundnut, soybean); also dyes (indigo), fodder and ornamentals (lupin, sweet pea).

Quick revision

Dicots: tap root, reticulate venation.
Monocots: fibrous root, parallel venation.
Potato is a modified stem.

Exam tips

Potato is a stem (has eyes = nodes); sweet potato is a root.
Practise floral formulae of key families: Fabaceae, Solanaceae and Liliaceae — they are asked often.

Practice MCQs

Potato is a modified
1. root
2. fruit
3. leaf
4. stem
Show answer
Answer: (d) stem. Has nodes (eyes).
Monocot leaves usually have
1. reticulate venation
2. net veins
3. no veins
4. parallel venation
Show answer
Answer: (d) parallel venation. Parallel.
Prop roots are found in
1. carrot
2. banyan
3. radish
4. mangrove only
Show answer
Answer: (b) banyan. Support.
In a hypogynous flower, the ovary is
1. superior
2. inferior
3. half-inferior
4. absent
Show answer
Answer: (a) superior. Other parts below it.
The edible part of a mango is the
1. epicarp
2. seed
3. endocarp
4. mesocarp
Show answer
Answer: (d) mesocarp. Fleshy middle layer.
Pneumatophores help in
1. respiration
2. storage
3. support
4. climbing
Show answer
Answer: (a) respiration. Mangroves.
Sweet potato is a modified
1. stem
2. root
3. leaf
4. bud
Show answer
Answer: (b) root. Adventitious root.
Vexillary aestivation is characteristic of
1. Solanaceae
2. Brassicaceae
3. Liliaceae
4. Fabaceae (pea)
Show answer
Answer: (d) Fabaceae (pea). Standard, wings, keel.

All chapters of Class 11 Biology

Written by Kundali IQ from standard, well-established facts to help with revision. This is not an official NCERT publication; always read your textbook too.