Definitions [6]
Definition: Flower
A modified, compressed reproductive shoot of angiosperms bearing sepals, petals, stamens, and carpels, meant for sexual reproduction, is called a flower.
Definition: Whorl
A circular arrangement of floral organs at the same level on the thalamus is called a whorl.
Definition: Thalamus (Receptacle)
The swollen terminal part of the pedicel on which all floral whorls are arranged is called the thalamus or receptacle.
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: Placentation
The pattern of ovule arrangement in the ovary is called placentation.
Key Points
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 Flower
- Flower: A modified shoot and the reproductive unit of angiosperms.
- Structure: Consists of four whorls—calyx, corolla (accessory), androecium, and gynoecium (reproductive).
- Types by sex: Flowers may be unisexual (male/female) or bisexual (both present).
- Symmetry: Actinomorphic (radial), zygomorphic (bilateral), or asymmetric.
- Based on floral parts: Flowers can be trimerous, tetramerous, or pentamerous depending on the number of parts.
- Position of ovary: Hypogynous (superior), perigynous (half inferior), epigynous (inferior).
