Frank Brothers Solutions for ICSE Class 9 Biology Chapter 7 Flowers

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Answer 1 :
A flower is the reproductive unit in angiosperms. It is a modified shoot in which internodes are shortened and leaves are modified into floral structure. Flower is meant for sexual reproduction.
A typical flower has four different kinds of whorls arranged successively on the swollen parts of a flower stalk. Flower stalk consists of the stalk called pedicel and the swollen upper part called thalamus bearing the floral leaves.
The different floral whorls are calyx, corolla, androecium and gynoecium. Calyx and corolla are accessory whorls, while androecium and gynoecium are reproductive whorls.
Calyx - The calyx is the outermost whorl of the flower and its members are called sepals. Generally, sepals are green, leaf like and protect the inner whorls of the flower in bud stage. They are also involved in producing food by photosynthesis. The calyx may be gamosepalous (sepals united) or polysepalous (sepals free).
Corolla - It is the second whorl composed of floral leaves called petals. Petals are usually brightly coloured to attract insects for pollination. Petals also protect the inner whorls. Like calyx, corolla may be also free (gamopetalous) or united (polypetalous). The shape and colour of corolla vary greatly in plants.
Androecium - It is the third whorl and is the male reproductive whorl of a flower. Androecium is composed of one or more stamens. Each stamen consists of three parts:
1. Filament - It is the lower stalk of the stamen.
2. Anther - Filament bears a bilobed fertile structure called anther at its distal end. Each lobe contains two pollen sacs. The pollen grains are produced in pollen-sacs.
3. Connective - Filament of the stamen is extended in between the two anther lobes called connective.
Gynoecium - It is the innermost whorl and the female reproductive part of the flower. Gynoecium is made up of one or more carpels. A carpel consists of three parts namely stigma, style and ovary.
Ovary is the swollen basal part containing ovules. Each ovary bears one or more ovules attached to a flattened, cushion-like structure called placenta.
Style is the elongated thread like structure attached to the apex of the ovary. It connects the ovary to the stigma.
The stigma is situated at the tip of the style and is the receptive surface for pollen grains.
A flower is essentially the part of the plant that helps it make more plants. They turn into fruits and seeds after they are successfully pollinated.
Teacher's Tip: Remember the sequence of whorls from outside to inside using the acronym C-C-A-G (Calyx, Corolla, Androecium, Gynoecium).
Exam Tip: Always mention both the common name and the technical name of whorl members (like petals for corolla) to get full marks.

Answer 2 :
(a) Inflorescence - The arrangement of flowers on the floral axis is called inflorescence.
Function - Inflorescence facilitates the best arrangement and display of flowers on a branch without any sort of overcrowding. It also facilitates pollination via a prominent visual display and more efficient pollen uptake and deposition.
(b) Gynoecium - It is the innermost whorl of the flower bearing the female reproductive parts.
Function - The ovary of gynoecium produces ovules which bear the female gamete.
(c) Placentation - The manner in which placenta and ovules are arranged inside the ovary wall is known as placentation.
Function - Placentation helps in the best arrangement of ovules within the ovary. Placentation also helps in plant classification.
(d) Incomplete flower - A flower lacking one whorl out of the four whorls is said to be incomplete flower.
Function - An incomplete flower contains either male or female reproductive organs.
(e) Perianth - When the calyx and corolla are not distinct in a flower (eg. - lily), the whorl is collectively called perianth.
Function - The members of perianth, called tepals are usually brightly coloured and bear scent. This attracts insects which aids in pollination. They also protect the flower in bud condition.
These biological terms describe how different parts of a plant are organized to ensure survival. Understanding these structures helps us identify different plant families and how they reproduce.
Teacher's Tip: Think of a "Perianth" as a "combined coat" where you cannot tell the green sepals apart from the colorful petals.
Exam Tip: When defining incomplete flowers, always provide an example like a unisexual flower to illustrate your point.

Answer 3 :
Based on the position of calyx, corolla and androecium in respect to the ovary on thalamus, there are three floral whorl conditions. These are:
(i) Hypogyny - In this flower, the ovary occupies the highest position on the thalamus, while the petals, sepals and stamens are separately inserted below the ovary. The ovary in such flowers is said to be superior. E.g., mustard and china rose.
(ii) Perigyny - In this condition, the margin of the thalamus grows upwards to form a cup-shaped structure called calyx tube enclosing the ovary. The ovary here is said to be half inferior. E.g., plum and rose
(iii) Epigyny - In this flower, the margin of thalamus grows upwards enclosing the ovary completely and getting fused with it. The other parts of the flower are above the ovary. Hence, the ovary is said to be inferior. E.g. Sunflower, flowers of cucumber.
These terms describe where the "seed-making" part of the flower sits compared to the petals and sepals. It is like describing if a person is sitting on a chair, in a bucket, or under a table.
Teacher's Tip: Focus on the word "Hypo" (below) and "Epi" (above) to remember if the other parts are below or above the ovary.
Exam Tip: Draw simple line diagrams showing the ovary position relative to other whorls for these three types to score full marks.

Answer 4:
The flower is the reproductive unit in the angiosperms and is meant for sexual reproduction. Flowers produce seeds from which new plants grow in future. So the main function of flower is to perpetuate the species.
There are six different types of flowers. These are complete, incomplete, bisexual, unisexual, actinomorphic and zygomorphic.
The flower acts as the biological factory for producing the next generation of plants. Every part of it is designed to either protect the developing seed or attract helpers like bees.
Teacher's Tip: Remember that "perpetuate" simply means to keep the family line going forever.
Exam Tip: Mention that the primary goal of any flower is the production of seeds when asked about its function.

Answer 5:
(a) Calyx
It is the outermost whorl of flower.
Its members are called sepals.
Sepals of calyx protect the inner whorls of the flower in bud stage.
Corolla
It is the second whorl of flower.
Its members are called petals.
Petals are usually brightly coloured to attract insects for pollination; they also protect the inner whorls.
(b) Inflorescence
It refers to the arrangement of flowers on the floral axis.
Inflorescence is of two types - Racemose and cymose.
Flower
Flower is a modified shoot in which internodes are shortened and leaves are modified into floral structure.
Flowers are of six types - complete, incomplete, bisexual, unisexual, actinomorphic and zygomorphic.
(c) Androecium
It is the third whorl of a flower.
It is the male reproductive part of a flower.
Androecium is composed of one or more stamens.
Each stamen consists of filament, anther and a connective.
Androecium produces the male gametes.
Gynoecium
It is the innermost whorl of a flower and the female reproductive part of the flower.
It is the female reproductive part of the flower.
Gynoecium is made up of one or more carpels.
A carpel consists of three parts namely stigma, style and ovary.
Gynoecium produces the female gametes.
(d) Hypogyny
In this flower, the ovary occupies the highest position on the thalamus.
Here, the petals, sepals and stamens are separately inserted below the ovary.
The ovary in such flowers is said to be superior.
E.g. - mustard and china rose.
Perigyny
In this condition, the margin of the thalamus grows upwards to form a cup-shaped structure called calyx tube enclosing the ovary.
Here, other parts of the flower are located on the rim of the thalamus almost at the same level as the ovary.
The ovary here is said to be half inferior.
E.g., plum and rose.
(e) Complete flower
A flower having all four whorls is said to be a complete flower.
Eg. - Cotton
Incomplete flower
A flower lacking one whorl out of the four whorls is said to be an incomplete flower.
Eg. - Cucurbits
These comparisons help us understand the specific roles each part plays and how flowers vary in structure. By looking at these differences, we can better classify plants into different groups.
Teacher's Tip: When studying differences, always look for the main identifying feature like "outermost" vs "innermost".
Exam Tip: Use a T-chart format for distinction questions to make your answer clear and easy for the teacher to grade.

Answer 6:
In certain flowers like tomato and brinjal, the calyx remains attached even after the formation of the fruit and does not wither away. Such calyx is called persistent calyx.
Usually, flower parts fall off once the fruit starts growing, but some plants keep their "green hat" for protection. This is a special adaptation that helps protect the developing fruit from pests.
Teacher's Tip: Think of the green leafy part on top of a tomato; that is the persistent calyx!
Exam Tip: Mention "tomato" or "brinjal" as specific examples whenever you define persistent calyx.

Answer 7:
Calyx is the outermost whorl of a flower which is composed of sepals. Generally these sepals are green, leaf like and protect the inner whorls of the flower in bud condition. They are also involved in producing food by photosynthesis.
The calyx acts as a protective shield for the delicate parts of the flower before it blooms. Since they are green, they also help the plant by making food through sunlight.
Teacher's Tip: Remember that sepals look like tiny leaves because they are modified leaves.
Exam Tip: Do not forget to mention the role of photosynthesis when listing the functions of the calyx.

Answer 8:
There are 4 whorls present in a typical flower.
Whorls - Components
Calyx - Sepals
Corolla - Petals
Androecium - Stamens (anther, filament and connective)
Gynoecium - Carpels (stigma, style and ovary)
Each whorl has a specific component that carries out its unique function. This organized structure ensures that the flower can successfully produce seeds.
Teacher's Tip: Visualize the flower from the outside moving inward to remember the order of these whorls.
Exam Tip: If asked to list whorls, always include their corresponding components in brackets for a complete answer.

Answer 9:
Corolla is the second whorl composed of floral leaves called petals. Petals are usually brightly coloured to attract insects for pollination. Petals also protect the inner whorls. The shape and colour of corolla vary greatly in plants.
The corolla is the most visible part of the flower, designed to catch the eye of pollinators like bees and birds. Without these bright colors, many plants would struggle to reproduce.
Teacher's Tip: Think of the corolla as the "billboard" of the flower, advertising to insects.
Exam Tip: Be sure to state that attraction for pollination is the primary function of the corolla.

Answer 10:
The androecium and gynoecium are the essential parts of a flower because they are involved in sexual reproduction. Androecium is the male reproductive organ of a flower and is involved in producing male gametes. Gynoecium is the female reproductive part of the flower and produces the female gametes.
The non-essential or accessory parts of flowers are the calyx and corolla since they do not directly participate in the process of sexual reproduction leading to the development of seed. Sepals of calyx are green, leaf like and protect the inner whorls of the flower in bud stage. They are also involved in producing food by photosynthesis. Petals of corolla are usually brightly coloured to attract insects for pollination; they also protect the inner whorls.
Essential parts are like the "parents" of the future seed, while accessory parts are like the "house and decorations." Both are important, but only the essential parts actually create the new life.
Teacher's Tip: Remember "Essential" means "must-have" for making seeds, while "Accessory" means "helpful but not the main part".
Exam Tip: Clearly distinguish between essential and non-essential parts by using the term 'direct participation in reproduction'.

Answer 11:
In hypogynous flower, the ovary occupies the highest position on the thalamus, while the petals, sepals and stamens are separately inserted below the ovary. The ovary in such flowers is said to be superior. E.g., mustard and china rose.
In perigynous flower, the margin of the thalamus grows upwards to form a cup-shaped structure called calyx tube enclosing the ovary. The ovary here is said to be half inferior. E.g., plum and rose.
In epigynous flower, the margin of thalamus grows upward enclosing the ovary completely and getting fused with it. The other parts of the flower are above the ovary. Hence, the ovary is said to be inferior. E.g. Sunflower, flowers of cucumber.
The position of the ovary is a key feature used by scientists to identify different plant species. It also affects how the fruit eventually develops from the flower.
Teacher's Tip: Imagine the ovary as a queen; in hypogyny, she is on a high throne, while in epigyny, she is protected inside a chamber.
Exam Tip: Use the terms 'superior' and 'inferior' correctly when describing these flower types to show technical knowledge.

Answer 12:
(a)
Inflorescence
It refers to the arrangement of flowers on the floral axis.
Inflorescence is of two types - Racemose and cymose.
Flower
Flower is a modified shoot in which internodes are shortened and leaves are modified into floral structure.
Flowers are of six types - complete, incomplete, bisexual, unisexual, actinomorphic and zygomorphic.
(b)
Racemose inflorescence
Here oldest flower is at the base while the youngest flower is at the apex.
Here the main axis continues to grow.
Cymose inflorescence
Here oldest flower is in the centre and youngest flower towards the periphery.
Here, the main axis terminates in a flower, hence it is limited in growth.
(c)
Marginal placentation
There is a single placenta.
The single placenta develops along the junction of the two fused margins.
Eg. - Pea
Parietal placentation
Two or more placenta are present.
The ovary is unilocular and has two or more longitudinal placenta.
E.g. $Argemone$
(d)
Ray florets
They are arranged on the rim of the receptacle.
These florets may be sterile or fertile.
They are zygomorphic.
Disc florets
They are grouped in the centre.
These florets are bisexual.
They are actinomorphic.
Comparing these features helps us understand the incredible variety in how plants grow and produce flowers. Each pattern is a strategy for the plant to best interact with its environment and pollinators.
Teacher's Tip: In Racemose, think "Race" - the tip keeps racing upwards! In Cymose, it stops at a flower.
Exam Tip: When comparing inflorescence types, always mention the direction of growth of the main axis.

Answer 13:
(a) Androecium - It is the third whorl and is the male reproductive organ of a flower. Androecium is composed of one or more stamens. Each stamen consists of three parts: Filament, Anther and Connective. The pollen grains are produced in pollen-sacs on the anthers.
(b) Gynoecium - It is the innermost whorl and is the female reproductive part of the flower. Gynoecium is made up of one or more carpels. A carpel consists of three parts namely stigma, style and ovary. Ovary is the swollen basal part containing ovules.
(c) Calyx - The calyx is the outermost whorl of the flower and its members are called sepals. Generally, sepals are green, leaf like and protect the inner whorls of the flower in bud stage. They are also involved in producing food by photosynthesis. The calyx may be gamosepalous (sepals united) or polysepalous (sepals free).
(d) Corolla - It is the second whorl composed of floral leaves called petals. Petals are usually brightly coloured to attract insects for pollination. Petals also protect the inner whorls. Like calyx, corolla may be also free (gamopetalous) or united (polypetalous).
Each whorl has a vital role in the lifecycle of a flower, from protection and feeding to attraction and reproduction. Learning these parts helps us appreciate the complexity of even the smallest flower.
Teacher's Tip: Stamens (men) are male parts, and Carpels (sounds like 'car-pull') are female parts.
Exam Tip: Use the term 'gamosepalous' and 'polysepalous' specifically for the calyx to demonstrate advanced vocabulary.

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Answer 14:
(a) Datura
(b) Cotton
(c) Cotton
(d) Sunflower
(e) Tomato
(f) Mulberry
These examples show how different plants exhibit various floral characteristics we have studied. Knowing these specific plants helps ground our theoretical knowledge in real-world examples.
Teacher's Tip: Try to find these plants in a local garden to see these features for yourself.
Exam Tip: Memorize at least two examples for each floral type to be safe in the exam.

Answer 15:
(i) (b) condensed stem
(ii) (b) jointed calyx
(iii) (c) thalamus
(iv) (a) reniform
(v) (c) capitulum
These multiple-choice answers clarify the scientific classification of various flower parts and arrangements. They highlight the precision needed when identifying plant structures.
Teacher's Tip: "Reniform" means kidney-shaped, which is a common shape for some flower parts.
Exam Tip: Read all options carefully before choosing, as some terms might sound similar but have very different meanings.