Question
Draw a well-labelled diagram of a typical bisexual flower and name all the floral parts. Briefly state the function of each part.
(NCERT Class 12, Chapter 2 — Sexual Reproduction in Flowering Plants)
Solution — Step by Step
A typical flower has four concentric whorls attached to the receptacle: calyx → corolla → androecium → gynoecium, from outside to inside. This order is fixed — you will never see petals outside sepals in a normal flower.
Draw 5 leaf-like green structures at the base: these are sepals (collectively = calyx). Their job is to protect the bud before it opens. Inside them, draw 5 coloured, broad structures: these are petals (collectively = corolla). Petals attract pollinators — bright colour = insect pollination signal.
The stamen is the male reproductive unit. Each stamen has two parts:
- Filament — the stalk (draw a thin line)
- Anther — bilobed structure at the tip (draw a figure-8 shape on top of the filament)
The anther contains pollen sacs where pollen grains are produced. Label both parts clearly — examiners check for this.
Place the pistil at the centre. It has three parts stacked vertically:
- Stigma — sticky top surface where pollen lands
- Style — the tube connecting stigma to ovary
- Ovary — swollen base containing ovules (future seeds)
Draw a slightly swollen oval at the base, a thin neck above it, and a flattened/lobed top. Inside the ovary, show 1–2 small circles — these are the ovules.
Your complete diagram should have 8 labels minimum: sepal, petal, filament, anther, stigma, style, ovary, ovule. Add receptacle (the thickened end of the flower stalk) and peduncle (flower stalk) for full marks in NEET.
Why This Works
The flower is essentially a reproductive shortcut machine. The outer whorls (calyx + corolla) are non-reproductive but critical for protection and attraction. The inner two whorls — androecium and gynoecium — are the actual reproductive organs.
Pollen from the anther must reach the stigma (pollination), then travel down the style into the ovary to fertilise the ovule (fertilisation). The structural arrangement — tall filament, sticky stigma — is designed specifically to make this transfer efficient.
For NEET, think of the pistil as a building: stigma = roof (landing pad), style = elevator shaft, ovary = ground floor (where fertilisation happens). This analogy holds for every diagram question.
Alternative Method — Functional Grouping
Instead of memorising by whorls, group parts by function:
| Function | Part |
|---|---|
| Protection | Sepal |
| Attraction | Petal |
| Pollen production | Anther (on filament) |
| Pollen reception | Stigma |
| Pollen transport to ovule | Style |
| Seed formation | Ovary + Ovule |
This table also doubles as a quick revision tool two days before the exam.
Common Mistake
Most students draw the stigma as a single dot and forget the style entirely, connecting stigma directly to the ovary. The style is a distinct structure and carries marks separately. In NEET 2023, a 1-mark question specifically asked to name “the part of pistil through which the pollen tube grows” — the answer is the style, not the stigma.
For the anther, always draw it as bilobed (two lobes side by side, like the number 8 on its side). A single oval anther will cost you marks in board practicals. Each lobe contains two pollen sacs — so one anther = 4 pollen sacs total. This “4 microsporangia” fact is a direct NEET PYQ point.
Diagram Checklist Before You Submit
Before moving on in the exam, run this quick check:
- Receptacle and peduncle labelled at base
- At least 3 sepals and 3 petals visible
- Filament clearly distinct from anther
- Anther drawn as bilobed
- Stigma, style, and ovary all labelled as separate parts
- At least one ovule shown inside ovary
- All label lines are straight (use a ruler)
A diagram with all 8 core labels and clean lines will consistently score full marks in both CBSE boards and NEET.