The Flower - Questions & Answers

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

(i) Flowers can be complete or incomplete.
T

(ii) A flower typically has six floral whorls.
F

(iii) Bracts are usually green, but sometimes large and colourful.
T

(iv) Nasturtium has nectaries.
T

(v) Stamens and carpels are the male and female parts.
T

(vi) The prefix "gamo-" is used whenever any of the floral whorls are fused.
T

(vii) Stigma may be simple or divided into two or more lobes.
T

(viii) Papaya is monoecious plant.
F

1. Choose the correct answer from the options given below :

(i) Bougainvillea flower has :
(a) Large sepals (b) Large nectary (c) Large colourful petals (d) Large colourful bracts
(d) Large colourful bracts

(ii) A flower is said to be complete when :
(a) It has the corolla and calyx (b) It has the corolla and gynoecium (c) It has the androecium and gynoecium (d) It has all the four whorls.
(d) It has all the four whorls.

(iii) The part of the flower that gives rise to the fruit is
(a) Sepals (b) Petals (c) Ovary (d) Stamens
(c) Ovary

(iv) The part of the flower that gives rise to the seed is
(a) Ovary (b) Placenta (c) Ovule (d) Pollen grain
(c) Ovule

(v) The essential whorls of a flower are the
(a) Calyx and corolla (b) Stamen and ovary (c) Calyx and epicalyx (d) Androecium and gynoecium
(d) Androecium and gynoecium

(vi) Floral stalk is technically termed as :
(a) Petiole (b) Peduncle (c) Pedicel (d) Funicle
(c) Pedicel

(vii) Which part of the pistil serves as the landing place for pollen grains ?
(a) Style (b) Ovary (c) Stigma (d) Ovules
(c) Stigma

(viii) Perianth is the collective term for a group of :
(a) Sepals (b) Tepals (c) Bracts (d) Petals
(b) Tepals

(ix) The condition of androecium, when all the stamens are free from each other is termed as :
(a) Polyadelphous (b) Polysepalous (c) Polyandrous (d) Polypetalous
(c) Polyandrous

(x) The flower which contains both stamens and carpels is called as :
(a) Unisexual (b) Pistillate (c) Staminate (d) Hermaphrodite
(d) Hermaphrodite

(xi) Soumya tried to match the floral whorls with their constituting units. She tabulated the pairs as follows :
Unit (P) - Floral whorl (Perianth)
Unit (Q) - Floral whorl (Androecium)
Identify P and Q :
(a) P — Petals Q — Carpels
(b) P — Tepals Q — Stamens
(c) P — Sepals Q — Petals
(d) P — Carpels Q — Stamens
(b) P — Tepals Q — Stamens

(xii) 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 ?
(a) Ishan (b) Aashish (c) Palak (d) Payal
(c) Palak

(xiii) 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 ?
(a) (1) and (2) (b) (2) and (3) (c) (3) and (4) (d) (1) and (4)
(a) (1) and (2)

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

Column A
(a) Polyadelphous
(b) Pollen grains
(c) Free petals
(d) Non-essential
(e) Sweet fragrant liquid
Column B
(i) Polypetalous
(ii) Calyx, corolla
(iii) Nectar
(iv) Bombax
(v) Pollen sac
(a) - (iv) Bombax
(b) - (v) Pollen sac
(c) - (i) Polypetalous
(d) - (ii) Calyx, corolla
(e) - (iii) Nectar

2. Given alongside is the structure of the female reproductive part of a flower. Read the information given below 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) stigma which is covered with hairs or with glandular papillae. (b) 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 (c) carpels fused together. Ovary contains one or more rounded bodies, the (d) ovules which are attached to the wall of the ovary with (e) placenta.

3. 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 :

Functions:
1. Attracts insects for pollination.
2. Protects the inner whorls of the flower.
3. Produces pollen grains.
4. Develops into the fruit.
5. Landing place for pollen grains.
6. Bears all the floral whorls.
(a) (Petal) - 1. Attracts insects for pollination.
(b) (Sepal) - 2. Protects the inner whorls of the flower.
(c) (Receptacle) - 6. Bears all the floral whorls.
(d) (Anther) - 3. Produces pollen grains.
(e) (Ovary) - 4. Develops into the fruit.

4. Name :

(a) Four whorls of the flower
Calyx, Corolla, Androecium, and Gynoecium

(b) Two types of unisexual flowers
Staminate (male) flowers and Pistillate (female) flowers

(c) Two main parts of a Stamen
Filament and Anther

(d) Three main parts of a Pistil
Stigma, Style, and Ovary

(e) Three types of stamens on the basis of their cohesion.
Monadelphous, Diadelphous, and Polyadelphous

5. Give two examples of each :

(a) Monoecious plants
Maize and Cucumber (or Pumpkin)

(b) Dioecious plants
Palm and Papaya

(c) Imperfect flowers
Papaya and Palm

(d) Bisexual flowers
Hibiscus and Rose (or Lily)

6. Fill in the blanks with suitable words :

(a) The floral parts are borne on the thalamus (or receptacle) in four whorls.

(b) The collective name of petals is corolla.

(c) Calyx and corolla are accessory whorls of the flower.

(d) Placenta attaches the ovules to the wall of the ovary.

(e) The sweet fragrant liquid of flowers is termed as nectar.

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

(a) Sepals : Calyx :: Petals : Corolla

(b) Stamens : Androecium :: Pistil : Gynoecium

(c) Petals : Polypetalous :: Stamens : Polyandrous

(d) Green petals : Sepaloid :: Coloured sepals : Petaloid

(e) Pollen grains : Anther :: Ovules : Ovary

8. Name the type of androecium found in

(a) China rose
Monadelphous

(b) Bombax
Polyadelphous

(c) Pea
Diadelphous

1. Explain briefly the following terms :

(a) Incomplete flower
A flower in which one or more sets of the floral whorls are missing.

(b) Staminate flower
A unisexual flower which contains only the stamens (male reproductive parts).

(c) Pistillate flower
A unisexual flower which contains only the carpels (female reproductive parts).

(d) Bisexual flower
A flower which contains both stamens and carpels (hermaphrodite).

2. What is the difference between :

(a) Flower and inflorescence ?
A flower is a specialized shoot representing the reproductive organ of a plant, whereas inflorescence is the mode of arrangement of flowers on the axis of a plant.

(b) Petals and petaloid tepals ?
Petals are the individual units of the corolla (the second whorl). Petaloid tepals are non-green, coloured individual units of the perianth, found when sepals and petals look similar and cannot be differentiated.

3. Define the terms :

(a) Flower
A specialized shoot in which the leaves are modified into floral structures, acting as the reproductive organ in flowering plants.

(b) Inflorescence
The mode of arrangement of flowers on the axis of a plant.

(c) Placentation
The manner in which the ovules are arranged or attached to the wall of the ovary.

(d) Bract
A leaf-like structure in the axil of which a flower arises.

(e) Epicalyx
A second series of sepals situated outside the primary calyx, commonly found in flowers like Hibiscus.

4. Where are the following structures/parts located and what are their functions ?

(a) Placenta
Located inside the ovary. Function: It is the tissue that attaches the ovules to the wall of the ovary.

(b) Thalamus
Located at the enlarged tip of the flower stalk (pedicel). Function: It bears all the floral parts/whorls of the flower.

(c) Anther
Located at the tip (extremity) of the filament of a stamen. Function: It contains pollen sacs that produce and liberate pollen grains.

(d) Stigma
Located at the uppermost, terminal knob-like part of the pistil/carpel. Function: It serves as the landing place for pollen during pollination.

1. Distinguish between the following pairs :

(a) Monoecious and Dioecious plants
In monoecious plants, male and female flowers grow on the same plant (e.g., maize). In dioecious plants, male and female flowers grow on completely different plants (e.g., palm, papaya).

(b) Perfect and Imperfect flowers
A perfect (complete) flower contains all four floral whorls. An imperfect (incomplete) flower has one or more sets of floral whorls missing.

(c) Unisexual and Bisexual flowers
A unisexual flower has only one reproductive part (either stamens or carpels). A bisexual flower has both male and female reproductive parts (stamens and carpels).

(d) Essential and Non-essential whorls of a flower
Essential whorls (androecium and gynoecium) are directly concerned with reproduction. Non-essential whorls (calyx and corolla) do not directly participate in reproduction but protect the inner parts and attract pollinators.

(e) Polyandrous and Polyadelphous stamens
In a polyandrous condition, the stamens are completely free from each other. In a polyadelphous condition, the filaments of the stamens are united into several distinct groups (e.g., Bombax).

2. Why are the following described as stated :

(a) The androecium of pea flower is diadelphous
Because its ten stamens have their filaments united into two distinct bundles (nine stamens form a staminal tube while one remains free).

(b) Ray florets of sunflower as neuters
Because both male and female reproductive organs are lacking or sterile in these flowers.

(c) Salvia sepals as petaloid
Because the sepals in such flowers are non-green and brightly coloured like petals, helping in attracting insects.

3. What are bracts ? State their function.
Bracts are leaf-like structures in the axil of which a flower arises. Their main function is to protect the flower bud, and when they are large and colourful (as in Bougainvillea), they help attract insects for pollination.

4. Explain the terms Monadelphous, Diadelphous and Polyadelphous using suitable diagrams. In each case name a flower possessing such an androecium.
Monadelphous: The stamens are united in one single group by their filaments, with only the anthers free (e.g., China rose).
Diadelphous: The filaments are united into two bundles (e.g., Pea).
Polyadelphous: The filaments are united into several groups (e.g., Bombax).
(Students should draw the respective diagrams from their textbook illustrating these filament groupings.)

1. The figure given below represents generalised arrangement of the different parts of a bisexual flower. Name the parts numbered 1-10.
1. Stigma
2. Style
3. Ovary
4. Receptacle (Thalamus)
5. Anther
6. Filament
7. Petal (Corolla)
8. Sepal (Calyx)
9. Ovule
10. Pedicel (Stalk)

2. Given below 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?
Figure A represents a Stamen. The collective term for this organ is Androecium.

(b) Are the contents of the pollen sacs in B male or female ?
Male (they contain pollen grains which represent the male gametes).

(c) Can you state how the contents of the pollen sacs would come out ?
When fully matured, the pollen sacs rupture (burst open) to liberate the powdery pollen grains.

3. The figures (A, B, C and D) given below represent different kinds of androecium. Name the kinds of androecium (A, B, C and D) and give one example of a flower having each.
A: Polyandrous (Free stamens) - Example: Petunia
B: Monadelphous (One group) - Example: China rose
C: Diadelphous (Two groups) - Example: Pea
D: Polyadelphous (Several groups) - Example: Bombax

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

(a) Label two important parts of the male reproductive organ.
(Self-drawing exercise. Labels should be: Anther and Filament).

(b) Label four important parts of the female reproductive organ.
(Self-drawing exercise. Labels should be: Stigma, Style, Ovary, and Ovule).

(c) Write the collective name/whorl of each reproductive organ.
Male: Androecium. Female: Gynoecium (or Pistil).

(d) Name the unicellular, sexual structures produced in each.
Male: Pollen grains (producing male gametes). Female: Egg cell (inside the ovule).

(e) Name the parts of the female reproductive organ that develop into a fruit and seed respectively.
The ovary develops into the fruit, and the ovules develop into seeds.

5. 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
(Self-drawing exercise. Students should refer to textbook illustrations for these variations.)

(Choose the answer based on the codes given below.)
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

(i) Assertion (A) : All the flowers of angiospermic plants are complete or perfect.
Reason (R) : Angiospermic flowers can be either unisexual or bisexual.
(d) A is false but R is true.

(ii) 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.
(c) A is true but R is false.

(iii) 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.
(c) A is true but R is false.

(iv) 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.
(b) Both A and R are true but R is not the correct explanation of A.

(v) Assertion (A) : Calyx and corolla are considered as non-essential (or accessory) parts of a flower because they do not participate directly 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.
(b) Both A and R are true but R is not the correct explanation of A.

1. 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 that 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.
No, they are not epipetals. These large, colourful structures are actually bracts (leaf-like structures) which are easily mistaken for petals.

(b) Define the above structure.
A bract is a leaf-like structure in the axil of which a flower arises.

(c) Mention 3 colours of the above structure which can be seen in Bougainvillea.
Red, pink, and orange (or purple/white).

(d) Why do these structures become colourful ? Write their important role.
They become colourful to attract insects for cross-pollination. This is especially important because the actual flowers of Bougainvillea are very small and visually dull.

(e) If any other part of the flower becomes colourful like petals, what technical term can be used for it ?
Petaloid (for example, petaloid sepals or petaloid perianth).