Class 11 : Biology (In English) – Lesson 5. Morphology of Flowering Plants
EXPLANATION & SUMMARY
🌿✨ Introduction
🪴 Morphology deals with the external form, shape, and structure of organisms.
In flowering plants (angiosperms), it focuses on the visible organs — root, stem, leaf, flower, fruit, and seed 🌸.
🧠 It helps botanists and learners in identification, classification, and understanding adaptive features that enable survival in diverse environments 🌍.
💡 Concept:
Morphology → outer features
Anatomy → internal tissues
🌱 This chapter systematically explores each organ, its structure, functions, and modifications.
🌱 Root
🧬 Definition
The root is the descending, non-green part of the plant axis that grows towards gravity (positive geotropism) and towards water (positive hydrotropism). It provides anchorage, absorption, conduction, and sometimes storage.
🧭 Types of Root Systems
🌾 Tap Root System
➤ Develops from the radicle of the embryo
➤ Has one main root with lateral branches
➤ Typical of dicots (e.g., 🌸 mustard)
🍀 Fibrous Root System
➤ Arises from the base of the stem
➤ All roots are similar-sized
➤ Found in monocots (e.g., 🌾 wheat)
🌿 Adventitious Root System
➤ Originates from stem or leaves
➤ Examples: 🪴 Maize – prop roots; 🪻 Sweet potato – tuberous roots
🧪 Regions of a Young Root
🔹 Root cap – covers and protects apex
🔹 Region of cell division – meristematic cells
🔹 Region of elongation – cells enlarge, increasing length
🔹 Region of maturation – root hairs appear; absorb water 💧
🌿 Modifications of Roots
💡 Purpose: Adaptations for storage, support, respiration, or special roles 🌍
🧺 Storage Roots
🥕 Conical – carrot ⚪ Napiform – turnip 🔶 Fusiform – radish
🪵 Support Roots
🪴 Prop roots – banyan (hang like pillars)
🪜 Stilt roots – maize, sugarcane (from lower nodes)
💨 Respiratory Roots
🌾 Pneumatophores in mangroves (e.g., Rhizophora); grow upward for oxygen exchange 🫧
🌸 Special Modifications
🌱 Climbing roots – betel (adhesion)
🍀 Epiphytic roots – Vanda (velamen absorbs moisture)
☀️ Photosynthetic roots – Tinospora
✏️ Note: Each modification reflects ecological adaptation 🌎.
🌿 Stem
🧠 Definition
The stem is the ascending axis bearing branches, leaves, flowers, and fruits, conducting water, minerals, and food through vascular tissues 🍃.
⚙️ Functions
⚡ Support aerial parts
💧 Conduction via xylem (up) & phloem (down)
🌱 Photosynthesis in green stems
🧺 Storage of food in some species
🌾 Propagation by vegetative means
🌾 Stem Modifications
🧺 Underground (Perennation + Storage)
🥔 Tuber – potato
🧅 Bulb – onion
🌿 Rhizome – ginger
🍠 Corm – colocasia
🌱 Subaerial (Vegetative Propagation)
🌿 Runner – grass 🌸 Stolon – jasmine
💧 Sucker – mint 🌼 Offset – water hyacinth
🌳 Aerial (Modifications Above Ground)
🌀 Tendrils – climbing (grapevine)
🗡️ Thorns – defense (bougainvillea)
🍀 Phylloclade – flattened, photosynthetic stem (Opuntia)
💡 Concept: Modified stems ensure survival, defense, reproduction, and water conservation.
🍃 Leaf
🌱 Definition
The leaf is a green, flattened lateral organ borne on the stem at nodes; primary site of photosynthesis, transpiration, and gas exchange 🍀.
📖 Parts
🌿 Leaf base – may form a pulvinus (legumes)
🧵 Petiole – stalk linking leaf to stem
🍃 Lamina – flat blade performing photosynthesis
🧭 Venation
🟢 Reticulate – dicots (net-like)
🟡 Parallel – monocots (lines run side by side)
🌸 Phyllotaxy
➤ Alternate – one leaf/node (sunflower)
➤ Opposite – two leaves/node (calotropis)
➤ Whorled – three + leaves/node (alstonia)
🌿 Leaf Modifications
🎯 Tendrils – pea (climbing)
🛡️ Spines – cactus (defense)
🧺 Fleshy leaves – onion (storage)
🪰 Insectivorous leaves – pitcher plant, Venus flytrap
✏️ Note: Modifications reveal adaptations for protection, nutrition, or water storage.
🌸 Flower
🧬 Definition
The flower is the reproductive organ, a modified shoot responsible for sexual reproduction.
🌺 Four Whorls (on thalamus)
🟢 Calyx – sepals, protect bud
🔴 Corolla – petals, attract pollinators
🟣 Androecium – stamens, male part
🟡 Gynoecium – carpels, female part
🧠 Symmetry
🌀 Actinomorphic – radial (mustard)
↔️ Zygomorphic – bilateral (pea)
🧭 Ovary Position
🍃 Superior – hypogynous (mustard)
🌼 Half-inferior – perigynous (rose)
🍏 Inferior – epigynous (guava)
🪻 Aestivation
🌸 Valvate – edges touch, no overlap
🌺 Twisted – overlap one side
🌼 Imbricate – irregular overlap
🐝 Vexillary – pea family (standard, wings, keel)
💡 Concept: Floral structure is crucial for taxonomy and pollination biology.
🍈 Fruit
🌿 Definition
A fruit develops from the ovary after fertilization 🍎; encloses and protects seeds.
Sometimes develops without fertilization → parthenocarpic (banana).
🧬 Types
🍎 True – ovary only (mango)
🍏 False – ovary + other parts (apple)
🍓 Aggregate – many ovaries, one flower (strawberry)
🍍 Composite – whole inflorescence (pineapple)
✏️ Note: Fruits aid in seed dispersal by wind, water, or animals.
🌾 Seed
🧠 Definition
Seed = mature ovule with embryo, cotyledon(s), seed coat; ensures species continuity.
🌿 Dicot Seed (Bean)
🧅 Two cotyledons storing food
🌿 Embryo → plumule + radicle
🧠 Non-endospermic
🌾 Monocot Seed (Maize)
🌾 One cotyledon (scutellum)
🍬 Endosperm supplies food
🌱 Embryo with plumule and radicle
💡 Concept: Seed structure reflects germination strategy and nutrient storage.
🌍 Why This Lesson Matters
🌿 Forms basis of plant taxonomy & identification
🧬 Explains organ adaptations for environment
🧠 Essential for NEET / JEE Biology concepts
⚡ Links form → function; aids agricultural innovation 🌾
📝 Quick Recap
🌱 Root – tap, fibrous, adventitious; modified for storage, support, respiration
🪴 Stem – conducts, supports; underground, subaerial, aerial modifications
🍃 Leaf – photosynthesis; varied venation & phyllotaxy; adaptations
🌸 Flower – four whorls; symmetry, ovary position, aestivation types
🍈 Fruit – true, false, aggregate, composite; dispersal unit
🌾 Seed – dicot vs monocot; ensures propagation
📘 Summary
Morphology studies external parts of angiosperms—root, stem, leaf, flower, fruit, and seed—each specialized for survival and reproduction.
Roots absorb and anchor; stems support, transport, and modify for storage or defense; leaves photosynthesize and adapt to environment; flowers enable sexual reproduction; fruits protect and disperse seeds; seeds ensure continuity.
Understanding these structures assists in classification, agriculture, horticulture, and ecology, and builds a strong base for higher biological studies.
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QUESTIONS FROM TEXTBOOK
🔵 Question 1. How is a pinnately compound leaf different from a palmately compound leaf?
🟢 Answer:
🌿 In a pinnately compound leaf, the leaflets are arranged along both sides of a common axis (rachis), resembling a feather.
➡️ Example: Neem (Azadirachta indica).
🌸 In a palmately compound leaf, the leaflets are attached at a single point at the tip of the petiole, like fingers on a palm.
➡️ Example: Silk cotton (Bombax).
✔️ Key Difference: Arrangement of leaflets — along rachis (pinnate) vs. single point (palmate).
🔵 Question 2. Explain with suitable examples the different types of phyllotaxy.
🟢 Answer:
🧬 Phyllotaxy is the pattern of arrangement of leaves on the stem or branch to provide optimum light exposure.
There are three main types:
🌿 Alternate phyllotaxy:
➡️ A single leaf arises at each node in alternate manner.
➡️ Example: China rose (Hibiscus), mustard.
🌸 Opposite phyllotaxy:
➡️ A pair of leaves arise opposite to each other at each node.
➡️ Example: Calotropis, guava.
🍃 Whorled phyllotaxy:
➡️ More than two leaves arise in a whorl at a node.
➡️ Example: Alstonia.
✔️ Purpose: Maximizes photosynthesis by minimizing overlap.
🔵 Question 3. Define the following terms:
🟢 Answer:
(a) 🌼 Aestivation: The mode of arrangement of sepals or petals in a floral bud before it opens.
➡️ Example: Valvate, twisted, imbricate, vexillary.
(b) 🧫 Placentation: The arrangement of ovules within the ovary.
➡️ Types: Marginal, axile, parietal, free central, basal.
(c) 🌸 Actinomorphic: When a flower can be divided into two equal halves by any vertical plane passing through the centre.
➡️ Example: Mustard.
(d) 🌼 Zygomorphic: When a flower can be divided into two equal halves only by one particular vertical plane.
➡️ Example: Pea.
(e) ⚗️ Superior ovary: Ovary is placed above the other floral parts; flower is hypogynous.
➡️ Example: Mustard.
(f) 🧪 Perigynous flower: Ovary is situated in the centre, and other floral parts are at the rim of the thalamus at same level.
➡️ Example: Peach.
(g) 🌿 Epipetalous stamen: Stamens are attached to petals.
➡️ Example: Brinjal.
🔵 Question 4. Differentiate between:
🟢 Answer:
(a) 🌸 Racemose and Cymose Inflorescence:
Feature Racemose Cymose
Growth Main axis shows indefinite growth Main axis shows definite growth
Flowers Older flowers at base, younger towards apex Older flowers at apex, younger towards base
Example Mustard Jasmine
(b) 🌿 Apocarpous and Syncarpous Ovary:
Feature Apocarpous Syncarpous
Carpels Free Fused
Example Michelia Hibiscus
🔵 Question 5. Draw the labelled diagram of the following:
(i) Gram seed
(ii) V.S. of maize seed
🟢 Answer:
✏️ (i) Gram Seed: Describe diagram — shows seed coat, micropyle, hilum, cotyledons, embryo.
✏️ (ii) V.S. of Maize Seed: Shows endosperm, scutellum, embryo, coleoptile, coleorhiza.
💡 diagrams are not drawn — describe them clearly as above.
🔵 Question 6. Take one flower of the family Solanaceae and write its semi-technical description. Also draw their floral diagram.
🟢 Answer:
🌸 Example: Datura
Habit: Herb
Root: Taproot
Stem: Erect, branched
Leaves: Alternate, simple
Inflorescence: Solitary, axillary
Flower: Bisexual, actinomorphic
Calyx: 5, united (gamosepalous)
Corolla: 5, united (gamopetalous), funnel-shaped
Androecium: 5 stamens, epipetalous
Gynoecium: Bicarpellary, syncarpous, superior ovary, axile placentation
Fruit: Capsule
Seed: Endospermic
💡 Floral formula: ⚥ K(5) C(5) A5 G(2)
📜 Floral diagram: Central ovary with five united petals and sepals, stamens alternate with petals.
🔵 Question 7. Describe the various types of placentations found in flowering plants.
🟢 Answer:
🧫 Placentation refers to the arrangement of ovules within the ovary. Types:
🌿 Marginal: Ovules attached along margin of ovary. → Pea
🌸 Axile: Ovules on central axis with septa. → Lemon
🌾 Parietal: Ovules on inner wall of ovary. → Mustard
🧬 Free Central: Ovules on central axis, no septa. → Dianthus
⚗️ Basal: Single ovule at base. → Sunflower
🔵 Question 8. What is a flower? Describe the parts of a typical angiosperm flower.
🟢 Answer:
🌸 Flower is the reproductive unit of angiosperms meant for sexual reproduction.
🧠 Parts:
Calyx (Sepals): Outer whorl, protective.
Corolla (Petals): Attractive, aids pollination.
Androecium (Stamens): Male reproductive part.
Gynoecium (Carpels): Female reproductive part with stigma, style, ovary.
✔️ Function: Produces gametes and facilitates fertilization.
🔵 Question 9. Define the term inflorescence. Explain the basis for the different types of inflorescence in flowering plants.
🟢 Answer:
🌿 Inflorescence is the arrangement of flowers on the floral axis.
🧬 Basis of classification:
➡️ Determinate or Indeterminate growth of main axis.
🌸 Types:
Racemose: Main axis grows continuously; younger flowers at top.
Cymose: Main axis ends in a flower; limited growth.
🔵 Question 10. Describe the arrangement of floral members in relation to their insertion on thalamus.
🟢 Answer:
🧠 Arrangement is based on position of ovary:
🌿 Hypogynous: Ovary superior; other parts below. → Mustard
🌸 Perigynous: Ovary in centre, other parts on rim. → Peach
🧬 Epigynous: Ovary inferior; other parts above. → Guava
✔️ Significance: Helps identify flower type and ovary position.
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OTHER IMPORTANT QUESTIONS FOR EXAMS
(CBSE MODEL QUESTIONS PAPER)
ESPECIALLY MADE FROM THIS LESSON ONLY
🔴 Question 1:
Which among the following is an underground modification of stem?
🔴1️⃣ Carrot 🥕
🟢2️⃣ Sweet potato 🍠
🟡3️⃣ Potato 🥔
🔵4️⃣ Turnip
🟢 Answer: 3️⃣ Potato 🥔
🔴 Question 2:
Which of the following is a tap root modification for storage?
🔴1️⃣ Carrot 🥕
🟢2️⃣ Sweet potato 🍠
🟡3️⃣ Maize 🌾
🔵4️⃣ Grass
🟢 Answer: 1️⃣ Carrot 🥕
🔴 Question 3:
Which part of the plant performs photosynthesis in Opuntia 🌵?
🔴1️⃣ Stem
🟢2️⃣ Leaves
🟡3️⃣ Root
🔵4️⃣ Flowers 🌸
🟢 Answer: 1️⃣ Stem
🔴 Question 4:
In Cuscuta, the type of root present is:
🔴1️⃣ Tap root
🟢2️⃣ Adventitious root
🟡3️⃣ Haustorial root
🔵4️⃣ Respiratory root
🟡 Answer: 3️⃣ Haustorial root
🔴 Question 5:
Which of the following plants show prop roots?
🔴1️⃣ Maize 🌾
🟢2️⃣ Banyan tree 🌳
🟡3️⃣ Sugarcane
🔵4️⃣ Coconut 🌴
🟢 Answer: 2️⃣ Banyan tree 🌳
🔴 Question 6:
Leaves arranged alternately on stem are seen in:
🔴1️⃣ China rose 🌸
🟢2️⃣ Calotropis
🟡3️⃣ Alstonia
🔵4️⃣ Guava 🍈
🟢 Answer: 1️⃣ China rose 🌸
🔴 Question 7:
The pattern of veins and veinlets in a leaf is called:
🔴1️⃣ Venation
🟢2️⃣ Phyllotaxy
🟡3️⃣ Aestivation
🔵4️⃣ Vernation
🟢 Answer: 1️⃣ Venation
🔴 Question 8:
Parallel venation is the characteristic feature of:
🔴1️⃣ Dicot plants 🌻
🟢2️⃣ Monocot plants 🌾
🟡3️⃣ Gymnosperms 🌲
🔵4️⃣ Bryophytes
🟢 Answer: 2️⃣ Monocot plants 🌾
🔴 Question 9:
In pea plant 🌿, the leaf modification is:
🔴1️⃣ Spines
🟢2️⃣ Tendrils
🟡3️⃣ Pitcher
🔵4️⃣ Hooks
🟢 Answer: 2️⃣ Tendrils
🔴 Question 10:
Which among the following is an underground stem for vegetative propagation?
🔴1️⃣ Ginger
🟢2️⃣ Carrot 🥕
🟡3️⃣ Sweet potato 🍠
🔵4️⃣ Turnip
🟢 Answer: 1️⃣ Ginger
🔴 Question 11:
What is phyllotaxy? Mention its types.
🟢 Answer:
Phyllotaxy — arrangement of leaves on stem or branch for maximum sunlight 🌞.
Types:
1️⃣ Alternate: One leaf per node (e.g. China rose 🌸).
2️⃣ Opposite: Two leaves per node opposite each other (e.g. Calotropis).
3️⃣ Whorled: More than two leaves per node (e.g. Alstonia).
🔴 Question 12:
Define aestivation and give its types.
🟢 Answer:
Aestivation — arrangement of sepals or petals in floral bud 🌸 before opening.
Types:
1️⃣ Valvate: Margins do not overlap (e.g. Calotropis).
2️⃣ Twisted: Each petal overlaps the next (e.g. China rose 🌺).
3️⃣ Imbricate: Irregular overlapping (e.g. Cassia).
4️⃣ Vexillary: Largest petal covers others (e.g. Pea flower 🌼).
🔴 Question 13:
Describe the modifications of tap root for storage with examples.
🟢 Answer:
Tap roots store food and become fleshy.
Types:
1️⃣ Conical: Cone-shaped; broad at base, tapering at tip — Carrot 🥕.
2️⃣ Napiform: Spherical with narrow apex — Turnip, Beetroot.
3️⃣ Fusiform: Swollen in middle, tapering at both ends — Radish.
Function: Stores reserve food and helps in survival during adverse conditions.
🔴 Question 14:
What are modifications of adventitious roots? Give examples.
🟢 Answer:
1️⃣ Storage: Thick and fleshy roots storing food — Sweet potato 🍠.
2️⃣ Support:
• Prop roots: Hang from branches and provide support — Banyan tree 🌳.
• Stilt roots: Arise from lower nodes for support — Maize 🌾, Sugarcane.
3️⃣ Special functions:
• Respiratory roots: For gas exchange — Rhizophora.
• Sucking roots: Absorb nutrients from host — Cuscuta.
• Epiphytic roots: Absorb moisture — Orchid.
🔴 Question 15:
Write about stem modifications for different functions.
🟢 Answer:
1️⃣ Storage: Stores food and nutrients:
• Rhizome: Ginger
• Tuber: Potato 🥔
• Corm: Colocasia
• Bulb: Onion 🧅
2️⃣ Support:
• Stem tendrils for climbing — Cucumber, Pumpkin.
3️⃣ Protection:
• Thorns — Bougainvillea.
4️⃣ Photosynthesis:
• Phylloclade — Opuntia 🌵.
🔴 Question 16:
Describe leaf modifications and their functions.
🟢 Answer:
1️⃣ Tendrils: Climbing — Pea 🌿.
2️⃣ Spines: Protection — Cactus 🌵.
3️⃣ Storage leaves: Store food/water — Onion 🧅.
4️⃣ Pitcher leaves: Trap insects — Nepenthes.
5️⃣ Phyllode: Petiole performs photosynthesis — Acacia.
💡 Leaf modifications adapt plants to special habitats and functions.
🔴 Question 17:
Explain phyllotaxy and its types with examples.
🟢 Answer:
Definition: Arrangement of leaves on stem or branch.
Types:
1️⃣ Alternate: One leaf per node — China rose 🌸.
2️⃣ Opposite: Two leaves per node opposite each other — Calotropis.
3️⃣ Whorled: More than two leaves per node — Alstonia.
Function: Ensures maximum sunlight exposure 🌞.
🔴 Question 18:
What is venation? Explain its types.
🟢 Answer:
Definition: Arrangement of veins and veinlets in leaf lamina 🍃.
Types:
1️⃣ Reticulate venation: Veins form network — Dicot leaves (e.g. Pea 🌿).
2️⃣ Parallel venation: Veins run parallel — Monocot leaves (e.g. Maize 🌾).
Significance: Helps in conduction and mechanical support to leaf.
🔴 Question 19:
Describe the types of placentation with examples.
🟢 Answer:
Definition: Arrangement of ovules within ovary.
Types:
1️⃣ Marginal: Along margin — Pea 🌿.
2️⃣ Axile: On central axis — Lemon 🍋, Hibiscus 🌺.
3️⃣ Parietal: On inner wall — Mustard.
4️⃣ Free central: Around central column — Dianthus.
5️⃣ Basal: Single ovule at base — Sunflower 🌻.
🔴 Question 20:
Define aestivation and describe its types.
🟢 Answer:
Definition: Arrangement of sepals or petals in floral bud before it opens 🌸.
Types:
1️⃣ Valvate: Margins don’t overlap — Calotropis.
2️⃣ Twisted: Each petal overlaps the next — China rose 🌺.
3️⃣ Imbricate: Irregular overlapping — Cassia.
4️⃣ Vexillary (Papilionaceous): One large standard covers others — Pea 🌿.
🔴 Question 21:
What are the main parts of a typical flower?
🟢 Answer:
1️⃣ Calyx: Outer whorl, green sepals, protection.
2️⃣ Corolla: Coloured petals, attract pollinators 🐝.
3️⃣ Androecium: Male whorl; stamens produce pollen.
4️⃣ Gynoecium: Female whorl; carpels contain ovary, style, stigma.
After fertilization: ovary → fruit, ovules → seeds.
🔴 Question 22:
Explain different types of inflorescence.
🟢 Answer:
1️⃣ Racemose: Main axis grows indefinitely; acropetal flowering.
• Types: Raceme, Spike, Umbel, Head.
• Example: Mustard, Sunflower 🌻.
2️⃣ Cymose: Main axis ends in flower; basipetal order.
• Example: Jasmine.
3️⃣ Special types: Cyathium (Euphorbia), Hypanthodium (Ficus 🌳).
🔴 Question 23:
Describe the structure of a typical flower 🌸 with its parts and functions.
🟢 Answer:
A flower is a reproductive organ of angiosperms, borne on thalamus.
Main parts:
1️⃣ Calyx:
• Outermost whorl; green sepals protect bud.
2️⃣ Corolla:
• Coloured petals; attract pollinators 🐝.
3️⃣ Androecium:
• Male reproductive whorl; stamens produce pollen grains.
4️⃣ Gynoecium:
• Female reproductive part; carpels with ovary, style, stigma.
Function:
✅ Reproduction by formation of gametes.
✅ After fertilization, ovary forms fruit 🍎, ovules form seeds 🌱.
🔴 Question 24:
Explain the types of fruits 🍎 with suitable examples.
🟢 Answer:
Definition: A fruit is a ripened ovary formed after fertilization.
Types:
1️⃣ Simple fruit: From single ovary of one flower — Mango 🥭, Tomato 🍅.
2️⃣ Aggregate fruit: From multiple ovaries of a single flower — Strawberry 🍓.
3️⃣ Multiple (Composite) fruit: From inflorescence — Pineapple 🍍.
Pericarp: Differentiated into epicarp, mesocarp, endocarp.
Function: Protection and seed dispersal.
🔴 Question 25:
Describe the structure of a dicot seed 🌱 with labelled parts.
🟢 Answer:
Example: Bean seed.
Parts:
1️⃣ Seed coat:
• Outer testa, inner tegmen — protection.
2️⃣ Embryo:
• Plumule (future shoot), radicle (future root), and two cotyledons.
3️⃣ Hilum: Scar where seed attached to fruit.
4️⃣ Micropyle: Tiny pore for water entry.
Feature: Two cotyledons store food.
Type: Non-endospermic (food in cotyledons).
🔴 Question 26:
Explain structure of a monocot seed 🌾 with an example.
🟢 Answer:
Example: Maize seed 🌽.
Parts:
1️⃣ Seed coat fused with fruit wall.
2️⃣ Endosperm: Large, stores food.
3️⃣ Embryo:
• Single cotyledon (scutellum).
• Plumule covered by coleoptile, radicle by coleorhiza.
Type: Endospermic seed.
Function: Nutrition and protection of embryo.
🔴 Question 27:
Write a note on flower symmetry and sexuality in flowers 🌸.
🟢 Answer:
Symmetry:
1️⃣ Actinomorphic: Radial symmetry — Mustard, Datura.
2️⃣ Zygomorphic: Bilateral symmetry — Pea 🌿, Gulmohar.
3️⃣ Asymmetrical: No symmetry — Canna.
Sexuality:
1️⃣ Bisexual: Both stamens and carpels — Hibiscus 🌺.
2️⃣ Unisexual: Either stamens or carpels — Papaya, Maize 🌾.
Function: Helps in pollination type and classification.
🔴 Question 28:
Describe the structure and types of floral symmetry and aestivation.
🟢 Answer:
Floral symmetry:
1️⃣ Actinomorphic: Radial — Mustard.
2️⃣ Zygomorphic: Bilateral — Pea 🌿.
3️⃣ Asymmetrical: No symmetry — Canna.
Aestivation: Arrangement of petals/sepals in floral bud.
• Valvate: Calotropis
• Twisted: China rose 🌺
• Imbricate: Cassia
• Vexillary: Pea 🌿
These are key characters in floral formula and taxonomy.
🔴 Question 29:
What is a floral formula? Explain symbols used with example.
🟢 Answer:
Definition: Symbolic representation of flower structure.
Symbols:
⚫ ⚥ → Bisexual
⚫ ♂ / ♀ → Unisexual
⚫ ⊕ → Actinomorphic
⚫ % → Zygomorphic
⚫ K → Calyx
⚫ C → Corolla
⚫ A → Androecium
⚫ G → Gynoecium
Example: Pea 🌿
🔹 Floral formula: % ⚥ K(5) C1+2+(2) A(9)+1 G1
Shows number and fusion of floral parts.
🔴 Question 30:
Discuss pollination types and their significance.
🟢 Answer:
Pollination: Transfer of pollen from anther to stigma.
Types:
1️⃣ Self-pollination (Autogamy): Same flower — Pea 🌿.
2️⃣ Geitonogamy: Different flowers on same plant — Maize 🌾.
3️⃣ Cross-pollination (Xenogamy): Different plants — Papaya.
Agents: Wind 🌬️, Water 💧, Insects 🐝, Birds 🕊️.
Significance:
✔️ Genetic variation
✔️ Evolution
✔️ Seed and fruit formation
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