Definitions [8]
Define the term inflorescence.
- A flower is a modified shoot wherein the shoot apical meristem changes to a floral meristem. Internodes do not elongate and the axis gets condensed.
- The apex produces different kinds of floral appendages laterally at successive nodes instead of leaves. When a shoot tip transforms into a flower, it is always solitary. The arrangement of flowers on the floral axis is termed inflorescence.
Definition: Whorl
A circular arrangement of floral organs at the same level on the thalamus is called a whorl.
Definition: Perianth
When calyx and corolla are not differentiated, the floral envelope is called the perianth.
Definition: Tepals
Individual members of the perianth are called tepals.
Definition: Flower
A modified, compressed reproductive shoot of angiosperms bearing sepals, petals, stamens, and carpels, meant for sexual reproduction, is called a flower.
Definition: Thalamus (Receptacle)
The swollen terminal part of the pedicel on which all floral whorls are arranged is called the thalamus or receptacle.
Define the following:
Seed
Seed is defined as a fertilized mature ovule which possesses an inactive embryo and reserve food for its further development.
Define the following term:
Superior ovary
- Superior ovary Flowers with a superior ovary structure have the gynoecium at the top and the remaining floral components positioned underneath it.
- This arrangement of flowers is referred to as hypogynous. Mustard and brinjal are two examples.
Key Points
Key Points:
| Part of Flower | Whorl Type | Main Components | Function |
|---|---|---|---|
| Calyx | Accessory whorl | Sepals | Protect inner floral parts |
| Corolla | Accessory whorl | Petals | Attract insects for pollination |
| Androecium | Essential whorl | Stamens (filament + anther) | Male reproduction; pollen formation |
| Gynoecium | Essential whorl | Carpels (stigma, style, ovary) | Female reproduction; seed and fruit formation |
Key Points: Types of Flowers
| Basis of Classification | Type | Key Features | Examples |
|---|---|---|---|
| Presence of whorls | Complete | All four whorls present | Hibiscus, Mustard |
| Presence of whorls | Incomplete | One or more whorls absent | Maize, Papaya |
| Essential whorls | Neuter | Androecium and gynoecium absent | Ray florets of sunflower |
| Sex organs | Perfect (Bisexual) | Both androecium and gynoecium present | Hibiscus, Mustard |
| Sex organs | Imperfect (Unisexual) | Either androecium or gynoecium present | Papaya, Cucumber |
| Distribution of sex | Monoecious | Male and female flowers on same plant | Maize, Cucurbits, Coconut |
| Distribution of sex | Dioecious | Male and female flowers on different plants | Papaya, Date palm |
| Distribution of sex | Polygamous | Bisexual and unisexual flowers on same plant | Cotton, Sunflower |
| Position of ovary | Hypogynous | Ovary superior | Mustard, Tomato |
| Position of ovary | Perigynous | Ovary semi-inferior | Rose, Peach, Strawberry |
| Position of ovary | Epigynous | Ovary inferior | Cucumber, Apple |
Key Points: The Seed
- Seed is the fertilised ovule and final product of sexual reproduction in angiosperms.
- It consists of seed coat, cotyledons and embryo axis; food is stored mainly in cotyledons or endosperm.
- Seeds may be albuminous (endosperm present) or non-albuminous (endosperm absent); perisperm may persist in some seeds.
- Dormancy and dehydration help seeds survive adverse conditions and allow long-term storage.
- Seeds ensure dispersal, protection, nourishment of embryo, genetic variation and agricultural sustainability.
Concepts [20]
- Plant Morphology
- The Root
- The Stem
- The Leaf
- The Inflorescence
- Flower
- Flower Symmetry
- Types of Flowers
- The Fruit
- The Seed
- Structure of Dicotyledonous seed vs. Monocotyledonous seed
- Structure of a Dicotyledonous Seed
- Structure of Monocotyledonous Seed
- Semi-technical Description of a Typical Flowering Plant
- Solanaceae
- Malvaceae
- Cruciferae (Brassicaceae)
- Leguminosae
- Compositae
- Graminae
