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Class 9 SELINA Solutions Biology Chapter 4 - The Flower

The Flower Exercise Ex. 1

Solution A

1. (d) large colourful bracts

2. (d) It has all the four whorls.

3. (c) Ovary

4. (c) Ovule

5. (d) Androecium and gynoecium

Solution B.1

Column A 

Column B 

(a) Polyadelphous

(i) Bombax

(b) Pollen grains

(ii) Pollen sac

(c) Free petals

(iii) Polypetalous

(d) Non-essential

(iv) Calyx, corolla

(e) Sweet fragrant fluid

(v) Nectar

 

Solution C.1

(a) Incomplete flower - If one or more sets of floral structures are missing, the flower is called incomplete flower. E.g. American elm. 

(b) Staminate flower - A unisexual flower which contains only the stamens, i.e., male parts of a flower is called male or staminate flower. E.g. Eastern cottonwood. 

(c) Pistillate flower - A flower which contains only the carpels, i.e., female parts of a flower is called female or pistillate flower. E.g. Date palm.

(d) Bisexual flower - A flower which contains both stamens and carpels is called bisexual or hermaphrodite flower. E.g. Hibiscus.

Solution C.2

(a) Flower and Inflorescence

 

Flower

Inflorescence

Flower is a specialized shoot in which the leaves are modified into floral structures.

Inflorescence is the mode of arrangement of flowers on the axis of the plant.

 

(b) Petals and Petaloid sepals

 

Petals

Petaloid sepals

Petals are non-essential parts of a flower which help in protection of reproductive parts and make the flower attractive for pollination.

Undifferentiated petals and sepals together form the perianth. When perianth is non-green, it is called a petaloid.

 

(c) Polyandrous and polyadelphous androecium

Polyandrous androecium

Polyadelphous androecium

In polyandrous androecium, filaments of the stamens are free.

In polyadelphous androecium, filaments of the stamens are united in several groups.



Solution C.3

(a) Placenta:

Location: Cushion or swollen region in the ovary

Function: Gives origin to ovules

(b) Thalamus:

Location: Tip of the flower stalk

Function: Bears all the parts of the flower

(c) Anther:

Location: Part of the stamen

Function: Produces male gametes or pollen grains

(d) Stigma:

Location: Terminal knob-like part

Function: Serves as the landing place for pollen grains during pollination

Solution D.1

Types of androecium in flowers:

1.  Polyandrous: When the stamens of a flower are free, the condition is called polyandrous.

2.  Monadelphous: When the filaments of anthers in a flower are fused into one group, the condition is called monadelphous.

3.  Diadelphous: When the filaments of anthers in a flower are fused into two groups, the condition is called diadelphous.

4.  Polyadelphous: When the filaments of anthers in a flower are fused into more than two groups, the condition is called polyadelphous. 

Solution D.2

(a) China rose: Monadelphous

(b) Bombax: Polyadelphous

(c) Pea: Diadelphous 

Solution E.1

(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.

Solution E. 2

When a flower arises in the axil of a leaf-like structure, this structure is known as bract. Because bracts are large and brightly coloured structures, they are often mistaken for petals. This helps to attract insects for pollination.

Solution E. 3

 

Condition of androecium Explanation Example of flower
Monadelphous Filaments of the anthers in a flower are fused into one group Hibiscus
Diadelphous  Filaments of the anthers in a flower are fused into two groups Pea
Polyadelphous Filaments of the anthers in a flower are fused into more than two groups Bombax
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