The Flower

Mention if the following statements are true (T) or false (F)

1. Flowers can be complete or incomplete.
2. A flower typically has six floral whorls.
3. Bracts are usually green, but sometimes large and colourful.
4. Nasturtium has nectaries.
5. Stamens and carpels are the male and female parts.
6. The prefix "gamo-" is used whenever any of the floral whorls are fused.
7. Stigma may be simple or divided into two or more lobes.
8. Papaya is monoecious plant.

Answer

1. True
2. False
   Corrected statement — A flower typically has four floral Whorls.
3. True
4. True
5. True
6. True
7. True
8. False
   Corrected statement — Papaya is dioecious plant.

Bougainvillea flower has

1. Large sepals
2. Large nectary
3. Large colourful petals
4. Large colourful bracts

Answer

Large colourful bracts

Reason — In Bougainvillea, the flower arises in the axil of bracts, which become colourful.
Sepals are usually small, green, leaf-like structures. A nectary is the part that produces nectar to attract pollinators. Bougainvillea does have nectary. Bougainvillea’s actual petals are small and inconspicuous, not large or brightly colored.

A flower is said to be complete when:

1. It has the corolla and calyx
2. It has the corolla and gynoecium
3. It has the androecium and gynoecium
4. It has all the four whorls

Answer

It has all the four whorls

Reason — A flower with all the four whorls present, is known as complete flower.
Having corolla and calyx only, means missing reproductive parts. Having corolla and gynoecium only, means missing calyx and androecium. Having androecium and gynoecium only, means only reproductive parts, missing outer whorls.

The part of the flower that gives rise to the fruit is

1. Sepals
2. Petals
3. Ovary
4. Stamens

Answer

Ovary

Reason — Ovary is the swollen basal portion of the gynoecium that develop into fruit.
Sepals protect the flower bud, do not form fruit. Petals attract pollinators. Stamens are male reproductive part which produce pollen.

The part of the flower that gives rise to the seed is

1. Ovary
2. Placenta
3. Ovule
4. Pollen grain

Answer

Ovule

Reason — Ovule grows to form seed.
Ovary forms the fruit, not the seed. Placenta holds the ovules inside the ovary. Pollen grain contains male gametes but does not become the seed.

The essential whorls of the flower are the

1. Calyx and Corolla
2. Stamen and ovary
3. Calyx and epicalyx
4. Androecium and gynoecium

Answer

Androecium and gynoecium

Reason — The essential whorls of the flower are those that are directly concerned with reproduction. Androecium and gynoecium are the male and female reproductive parts of the flower, respectively.
Calyx and Corolla are accessory (non-essential) whorls. Stamen and ovary are parts of the essential whorls, not the whorls themselves. Epicalyx are non-essential structures.

Floral stalk is technically termed as :

1. Petiole
2. Peduncle
3. Pedicel
4. Funicle

Answer

Pedicel

Reason — Stalk of flower is called Pedicel.
Petiole is stalk of a leaf. Peduncle is main stalk of an inflorescence or a solitary flower (not individual flower stalk). Funicle is stalk attaching ovule to placenta inside the ovary.

Which part of the pistil serves as the landing place for pollen grains?

1. Style
2. Ovary
3. Stigma
4. Ovules

Answer

Stigma

Reason — Stigma is the top most portion of carpel that receives pollen grains.
Style connects stigma to ovary; does not receive pollen. Ovary contains ovules; site of fertilization and seed formation. Ovules develop into seeds after fertilization.

Perianth is the collective term for a group of:

1. Sepals
2. Tepals
3. Bracts
4. Petals

Answer

Tepals

Reason — In some cases, the sepals and petals look very similar and cannot be differentiated from one another. They are called tepals and collectively known as perianth.
Sepals is only one whorl, not the whole perianth. Bracts modified leaves, not part of perianth. Petals only corolla, not the entire perianth.

The condition of androecium, when, all the stamens are free from each other is termed as :

1. Polyadelphous
2. Polysepalous
3. Polyandrous
4. Polypetalous

Answer

Polyandrous

Reason — When the stamens are free, such condition is called Polyandrous.
In Polyadelphous, stamens are fused into more than two groups. In Polysepalous, sepals are free from each other. In Polypetalous, petals are free from each other.

The flower which contains both stamens and carpels is called as:

1. Unisexual
2. Pistillate
3. Staminate
4. Hermaphrodite

Answer

Hermaphrodite

Reason — The flower which contains both stamens and carpels is called a bisexual or hermaphrodite flower.
Unisexual flower has either stamens or carpels, not both. Pistillate flower is a female flower. So, carpels are present in it but stamens are absent. Staminate flower is a male flower. So, stamens are present but carpels are absent in it.

Soumya tried to match the floral whorls with their constituting units.
She tabulated the pairs as follows:

Identify P and Q

1. P — Petals, Q — Carpels
2. P — Tepals, Q — Stamens
3. P — Sepals, Q — Petals
4. P — Carpels, Q — Stamens

Answer

P — Tepals, Q — Stamens

Reason — When calyx and corolla are indistinguishable, they are known as tepals. Group of tepals is known as perianth. Group of stamen is known as androecium.
Carpels belong to gynoecium, not perianth. Petals belong to the corolla.

A biology teacher asked her students to give two examples of dioecious plants.

Ishan said: Maize and Palm.
Aashish said: Pumpkin and Papaya.
Palak said: Palm and Papaya.
Payal said: Pumpkin and Maize.

Who was correct?

1. Ishan
2. Aashish
3. Palak
4. Payal

Answer

Palak

Reason — Dioecious plants have male and female flowers on separate plants. Palm and Papaya are examples of dioecious plants.
Maize and Pumpkin are examples of monoecious plants where male and female flowers grow on the same plant.

The arrangement and distribution of flowers on a specialized branch of the plant is known as inflorescence.

(1) All flowering plants have the same type of inflorescence.

(2) Flowers always arise from the apical bud only.

(3) Flowers may arise from the axillary buds or terminal buds.

(4) Flowers may reach at the same level making a cluster.

Which of the above statements about inflorescence are incorrect ?

1. (1) and (2)
2. (2) and (3)
3. (3) and (4)
4. (1) and (4)

Answer

(1) and (2)

Reason — Flowering plants have different types of inflorescence. Flowers do not always arise from the apical bud; they can also arise from axillary buds.
Flowers may arise from the axillary buds or terminal buds depending on the plant type. Flowers appear at almost the same height forming a cluster.

Match the parts in column A with the flowers or parts of flower in column B.

Answer

Given alongside is the structure of the female reproductive part of a flower. Read the information given alongside and fill in the blanks :

Gynoecium is the innermost whorl of a flower which is made up of carpels. Its main function is production of female gametes that develop into seeds after the process of fertilization.

The terminal knob-like part of the pistil is (a) ............... which is covered with hairs or with glandular papillae. (b) ............... is the tubular slender stalk which connects the uppermost part to the lowest part of the pistil. Ovary is the swollen basal portion composed of one or many (c) ............... fused together. Ovary contains one or more rounded bodies, the (d) ............... which are attached to the wall of the ovary with (e) ............... .

Answer

The terminal knob-like part of the pistil is Stigma which is covered with hairs or with glandular papillae. Style is the tubular slender stalk which connects the uppermost part to the lowest part of the pistil. Ovary is the swollen basal portion composed of one or many Carpels fused together. Ovary contains one or more rounded bodies, the Ovules which are attached to the wall of the ovary with Placenta.

Given below is the generalized structure of a bisexual flower showing its various parts. Match the structures marked (a) to (e) with their correct functions:
Example: (f)-6: Bears all the floral whorls.

Answer

Name

1. Four whorls of the flower
2. Two types of unisexual flowers
3. Two main parts of a Stamen
4. Three main parts of a Pistil
5. Three types of stamens on the basis of their cohesion.

Answer

1. Calyx, Corolla, Androecium, Gynoecium
2. Staminate flowers, Pistillate flowers
3. Anther and Filament
4. Stigma, Style, Ovary
5. Monadelphous, Diadelphous, Polyadelphous

Give two examples of each :

1. Monoecious plants
2. Dioecious plants
3. Imperfect flowers
4. Bisexual flowers

Answer

1. Maize, Cucumber
2. Palm, Papaya
3. Palm, Papaya
4. Hibiscus, Rose

Fill in the blanks with suitable words :

1. The floral parts are borne on the ............... in four whorls.
2. The collective name of petals is ............... .
3. ............... and corolla are accessory whorls of the flower.
4. ............... attaches the ovules to the wall of the ovary.
5. The sweet fragrant liquid of flowers is termed as ............... .

Answer

1. The floral parts are borne on the thalamus in four whorls.
2. The collective name of petals is corolla .
3. Calyx and corolla are accessory whorls of the flower.
4. Placenta attaches the ovules to the wall of the ovary.
5. The sweet fragrant liquid of flowers is termed as nectar.

Note the relationship between the first two words and suggest a suitable word/words for the blank place.

1. Sepals : Calyx :: Petals : ...............
2. Stamens : ............... :: Pistil : Gynoecium
3. Petals : Polypetalous :: Stamens : ...............
4. Green petals : Sepaloid :: Coloured sepals : ...............
5. Pollen grains : Anther :: Ovules : ...............

Answer

1. Corolla
2. Androecium
3. Polyandrous
4. Petaloid
5. Ovary

Name the type of the androecium found in

1. China rose
2. Bombax
3. Pea

Answer

1. China rose — The type of androecium found is Monadelphous.
2. Bombax — The type of androecium found is Polyadelphous.
3. Pea — The type of androecium found is Diadelphous.

Explain briefly the following terms:

1. Incomplete flower
2. Staminate flower
3. Pistillate flower
4. Bisexual flower

Answer

1. Incomplete flower — A flower is said to be an incomplete flower if one or more sets of floral whorls are missing. E.g. American Elm.

2. Staminate flower — A unisexual flower which contains only the stamens is called the male or staminate flower. E.g. Eastern Cottonwood.

3. Pistillate flower — A flower which contains only the carpels is called the female or pistillate flower. E.g. Date Palm.

4. Bisexual flower — A flower which contains both stamens and carpels is called a bisexual or hermaphrodite flower. E.g. Rose.

What is the difference between:

(a) Flower and inflorescence?

(b) Petals and petaloid tepals?

Answer

(a) Difference between flower and inflorescence:

(b) Difference between petals and petaloid tepals:

Define the terms:

1. Flower
2. Inflorescence
3. Placentation
4. Bract
5. Epicalyx

Answer

1. Flower is specialized shoot in which the leaves are modified into floral structures.
2. Inflorescence is the mode of arrangement of flowers on the axis of a plant.
3. The manner of attachment of ovules to the wall of the ovary is called Placentation.
4. When a flower arises in the axil of a leaf-like structure, this structure is called Bract.
5. An additional whorl around the calyx of a flower is called Epicalyx.

Where are the following structure/parts located and what are their functions?

1. Placenta
2. Thalamus
3. Anther
4. Stigma

Answer

1. Placenta:
   Location — Cushion or swollen region in the ovary.
   Function — Attaches the ovules to the wall of the ovary.

2. Thalamus:
   Location — Tip of the flower stalk.
   Function — Bears all the parts of the flower.

3. Anther:
   Location — Part of the stamen.
   Function — Produces male gametes or pollen grains.

4. Stigma:
   Location — Terminal knob like part of the pistil.
   Function — Serves as the landing place for pollen grains during pollination.

Distinguish between the following pairs

(a) Monoecious and Dioecious plants

(b) Perfect and Imperfect flowers

(c) Unisexual and Bisexual flowers

(d) Essential and Non-essential whorls of a flower

(e) Polyandrous and Polyadelphous stamens

Answer

(a) Difference between Monoecious and Dioecious plants:

(b) Difference between Perfect and Imperfect flowers:

(c) Difference between Unisexual and Bisexual flowers:

(d) Difference between Essential and Non-essential whorls of a flower:

(e) Difference between Polyandrous and Polyadelphous stamens:

Why are the following described as stated :

(a) The androecium of pea flower is diadelphous.

(b) Ray flowers of sunflower as neuters.

(c) Salvia sepals as petaloid.

Answer

(a) It is because the filaments of anthers are united in two bundles. Nine out of ten stamens in a pea plant form a staminal tube. The tenth is free.

(b) Ray florets of sunflower are described as neuters because both male and female reproductive structures are lacking.

(c) Sepals of the salvia are petaloid as 3 sepals are red in colour and united as petals. Therefore, they are not differentiated from the petals.

What are bracts? State their function.

Answer

When a flower arises in the axil of a leaf like structure, this structure is known as bract. It may be green like leaves or at times they are coloured.

The function of bracts is to protect the flower during its development and maturation. They may cover the flower bud, providing a shield against physical damage, excessive light, or harsh weather conditions. Colourful bracts can help attract pollinators to the flower.

Explain the terms Monadelphous, Diadelphous and Polyadelphous using suitable diagrams. In each case name a flower possessing such an androecium.

Answer

1. Monadelphous — Stamens are united in one group by their filaments. Only anthers are free. E.g. China Rose.

2. Diadelphous — The filaments are united in two bundles. E.g. Pea.

3. Polyadelphous — The filaments are united in several groups. E.g. Bombax.

The figure given alongside represents generalised arrangement of the different parts of a bisexual flower. Name the parts numbered 1-10.

Answer

The parts labelled from 1 to 10 are as follows:

1. Anther
2. Filament
3. Ovule
4. Placenta
5. Stigma
6. Style
7. Ovary
8. Petal
9. Sepal
10. Receptacle / Thalamus

Given alongside are two figures (A & B) of a certain part of a flower. Study the figures carefully and answer the following questions:

(a) Which major organ of a flower does the figure A represent? What is the collective term for this organ?

(b) Are the contents of the pollen sacs in B, male or female?

(c) Can you state how the contents of the pollen sacs would come out?

Answer

(a) Figure A represents stamen. Stamens collectively form Androecium.

(b) Contents of the pollen sacs in B, are male gametes.

(c) The contents of the pollen sacs would come out through agents like air, wind, insects leading to pollination in flowers.

The figures (A, B, C and D) give below represent different kind of androecium. Name the kind of androecium (A, B, C and D) and give one example of a flower having each.

Answer

• A → Polyandrous. e.g. Petunia.
• B → Monadelphous. e.g. China Rose.
• C → Diadelphous. e.g. Pea.
• D → Polyadelphous. e.g. Bombax.

Draw a neat diagram of male (♂) and female (♀) reproductive organs of a flower.

(a) Label two important parts of the male reproductive organ.

(b) Label four important parts of the female reproductive organ.

(c) Write the collective name/whorl of each reproductive organ.

(d) Name the unicellular, sexual structures produced in each.

(e) Name the parts of the female reproductive organ that develop into a fruit and seed respectively.

Answer

Below is the labelled diagram of male (♂) and female (♀) reproductive organs of a flower:

(c) The collective name of male reproductive organs is Androecium and female reproductive organs is Gynoecium.

(d) Pollen grains are produced in male reproductive organs and Ovules are produced in female reproductive organs.

(e) Ovary develops into fruit and Ovules develop into seeds, respectively.

Draw either an entire flower or a part of it showing the following conditions :

(a) Polysepalous calyx

(b) Gamosepalous calyx

(c) Polypetalous corolla

(d) Gamopetalous corolla

(e) Bracteate flower

Answer

(a) Polysepalous calyx

(b) Gamosepalous calyx

(c) Polypetalous corolla

(d) Gamopetalous corolla

(e) Bracteate flower

Assertion (A): All the flowers of angiospermic plants are complete or perfect.

Reason (R): Angiospermic flowers can be either unisexual or bisexual.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

A is false but R is true.

Reason — Not all flowers of angiosperms are complete or perfect. A complete flower has all the four floral whorls — calyx, corolla, androecium and gynoecium. A perfect flower is bisexual, that is, it possesses both androecium and gynoecium. In angiosperms, some flowers are unisexual, such as those of papaya and maize, and therefore they are not perfect. Some flowers may also lack one or more whorls and are thus incomplete. Hence, Assertion (A) is false.

The Reason (R) is true because angiospermic flowers may be either unisexual or bisexual.

Therefore, A is false but R is true is the correct option.

Assertion (A): Dioecious plants bear unisexual flowers on different plants.

Reason (R): Dioecious plants bear staminate and pistillate flowers on the same plant at different locations.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

A is true but R is false.

Reason — In dioecious plants, the male and female unisexual flowers are borne on different plants. Therefore, A is true.
R is false because staminate and pistillate flowers occurring on the same plant at different positions is a characteristic of monoecious plants, not dioecious plants.

Therefore, A is true but R is false is the correct option.

Assertion (A): The kind of androecium in which the stamens are united in one group by their filaments is termed as Monadelphous.

Reason (R): Monadelphous stamens are found in Pea and Bombax flowers.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

A is True and R is False.

Reason — A is True because when stamens are united by their filaments into one bundle, it is called a monadelphous condition.
R is False as Pea has diadelphous stamens (united into two bundles). Bombax has polyadelphous stamens (united into more than two bundles).

Therefore, A is true but R is false is the correct option.

Assertion (A): Calyx is the outermost whorl of the flower.

Reason (R): Calyx is the whorl of sepals which protects the young flower bud. Calyx, when green, also performs photosynthesis.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

Both A and R are true but R is not the correct explanation of A.

Reason — The calyx is the outermost whorl of a flower, so A is true.
R is also true because the calyx consists of sepals, which protect the young flower bud and may also perform photosynthesis when green.
However, this does not explain why the calyx is the outermost whorl of the flower.

Therefore, Both A and R are true but R is not the correct explanation of A is the correct option.

Assertion (A): Calyx and corolla are considered as non-essential (or accessory) parts of a flower because they do not participate in the process of reproduction.

Reason (R): Calyx and corolla are not useless. They protect the reproductive parts of the flower. Corolla attracts insects for pollination which is the first step of reproduction.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

Both A and R are true and R is the correct explanation of A.

Reason — A is true as calyx and corolla are called non-essential or accessory floral parts because they do not directly take part in reproduction (unlike androecium and gynoecium).
R is true as the calyx protects the flower bud and corolla attracts insects for pollination, which aids reproduction.

Therefore, Both A and R are true and R is the correct explanation of A is the correct option.

Nidhi is a girl who loves to visit gardens and observe flowers. She used to categorize the flowers on the basis of their size, presence/absence of petiole, colour of the petals, etc. She observed the flowers of Bougainvillea and noticed thatok the actual flowers are dull and small, white in colour but are protected by some other colourful structures.

(a) Are these colourful structures epipetals ? Explain.

(b) Define the above structure.

(c) Mention 3 colours of the above structure which can be seen in Bougainvillea.

(d) Why do these structures become colourful ? Write their important role.

(e) If any other part of the flower becomes colourful like petals, what technical term can be used for it?

Answer

(a) No, these colourful structures are not epipetals. They are bracts. The term epipetalous refers to stamens that are attached to petals, whereas in Bougainvillea the coloured structures are modified leaf-like parts surrounding the flower.

(b) Bracts are modified leaf-like structures present at the base of a flower or inflorescence. They may sometimes become brightly coloured.

(c) Three colours seen in Bougainvillea bracts are:

1. Pink
2. Purple
3. Red

(d) These structures become colourful due to the presence of pigments such as anthocyanins. Their important role is to attract insects and other pollinators for pollination, since the actual flowers are small and inconspicuous.

(e) If any other part of the flower becomes petal-like or colourful, the technical term is petaloid.