Quick Summary
Reproductive morphology covers the structure of flowers, types of inflorescences, the arrangement of floral organs, pollination, fertilisation, and the development of fruits and seeds. The flower is the reproductive unit of angiosperms. This chapter requires diagram knowledge along with terminology.
The Flower — Structure
A flower is a modified shoot for sexual reproduction.
Whorls of a flower (outside to inside): 1. Calyx — Sepals (protect the bud) 2. Corolla — Petals (attract pollinators) 3. Androecium — Stamens (male: filament + anther) 4. Gynoecium — Pistil (female: stigma + style + ovary)
Key Terms
| Term | Meaning |
|---|---|
| Complete flower | All four whorls present |
| Incomplete flower | One or more whorls absent |
| Bisexual (perfect) | Both androecium and gynoecium |
| Unisexual | Only one of the two (staminate or pistillate) |
| Actinomorphic | Radial symmetry (rose, mustard) |
| Zygomorphic | Bilateral symmetry (pea, bean) |
| Hypogynous | Ovary superior (mustard, brinjal) |
| Perigynous | Ovary half-inferior (rose, plum) |
| Epigynous | Ovary inferior (guava, cucumber) |
Inflorescence — Types
An inflorescence is the arrangement of flowers on the floral axis.
Racemose (Indefinite)
| Type | Description | Example |
|---|---|---|
| Raceme | Pedicellate flowers on elongated axis | Mustard, radish |
| Spike | Sessile flowers on elongated axis | Wheat, Adhatoda |
| Catkin | Spike with unisexual flowers | Mulberry |
| Corymb | All flowers at same level (unequal pedicels) | Candytuft |
| Umbel | All flowers from one point | Coriander, carrot |
| Capitulum (head) | Sessile florets on flat receptacle | Sunflower |
| Spadix | Fleshy spike with spathe | Banana, Colocasia |
Cymose (Definite)
| Type | Description | Example |
|---|---|---|
| Monochasial | One branch below terminal flower | Heliotropium (helicoid) |
| Dichasial | Two branches | Jasmine, Stellaria |
| Polychasial | Many branches | Calotropis |
Aestivation
Arrangement of sepals or petals in the bud.
| Type | Description | Example |
|---|---|---|
| Valvate | Edge to edge, no overlap | Calotropis |
| Twisted | One edge overlaps next | Cotton, Hibiscus |
| Imbricate | Some overlap, some covered | Cassia, Gulmohar |
| Vexillary (descending imbricate) | Large posterior petal outermost | Pea, bean |
Placentation
Arrangement of ovules in the ovary.
| Type | Ovules attached to | Example |
|---|---|---|
| Marginal | Ventral suture | Pea |
| Axile | Central axis in multilocular ovary | Lemon, tomato |
| Parietal | Inner wall of unilocular ovary | Mustard, Argemone |
| Free central | Central axis, no septa | Dianthus, Primrose |
| Basal | Base of single ovule | Sunflower, marigold |
| Superficial | All surfaces of septa | Water lily |
Fruit and Seed
True fruit: Develops from ovary only (mango, tomato, pea). False fruit (pseudocarp): Includes parts other than ovary (apple — thalamus, cashew — pedicel).
Types of Fruits
| Type | Description | Example |
|---|---|---|
| Berry | Fleshy, many seeds | Tomato, banana, grape |
| Drupe | Fleshy with hard endocarp | Mango, coconut, plum |
| Pome | Fleshy thalamus | Apple, pear |
| Legume (pod) | Dry, dehiscent, monocarpellary | Pea, bean |
| Capsule | Dry, dehiscent, multicarpellary | Cotton, Datura |
| Caryopsis | Pericarp fused with seed coat | Wheat, maize, rice |
| Nut | Dry, indehiscent, hard pericarp | Cashew (true nut), Litchi |
Important Questions
One Mark
- Define aestivation.
- What type of placentation is found in pea?
- Name the type of inflorescence in sunflower.
- What is a pseudocarp? Give one example.
Short Answer (3 marks)
- Distinguish between racemose and cymose inflorescence with one example each.
- What is placentation? Describe marginal and axile placentation with examples.
- Draw the floral diagram of Fabaceae (pea family) and write its floral formula.
Long Answer (5 marks)
- Describe the different types of placentation with diagrams.
- Classify fruits into simple, aggregate, and composite. Give examples and distinguish between true and false fruits.
Common Mistakes
- Confusing floral symmetry: actinomorphic = radial (rose), zygomorphic = bilateral (pea) — not the other way.
- Racemose vs cymose: racemose opens from base upward (acropetal); cymose from apex downward (basipetal).
- Apple: many students say it is a true fruit — it is a FALSE fruit (thalamus is edible, not ovary wall).
- Coconut: the edible white part is endosperm (seed); the hard shell is endocarp (drupe).
Board Exam Tips
- Placentation types with diagrams are a standard 5-mark question — know all six with examples.
- Inflorescence types table (racemose vs cymose) appears as a 3-mark comparison question.
- Floral formula and floral diagram for Solanaceae (brinjal), Fabaceae (pea), and Liliaceae (lily) are board staples.
- NEET: False fruits, types of ovary position (hypogynous/perigynous/epigynous), and aestivation types appear often.
Frequently Asked Questions
Calyx (sepals), Corolla (petals), Androecium (stamens — male), Gynoecium (pistil — female). A flower with all four whorls is complete; one lacking any is incomplete. A flower with both stamens and pistil is bisexual (perfect).