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Placentation Types in Angiosperms: Marginal, Axile, Parietal, Basal and Free-Central

Biology · Sexual Reproduction in Flowering Plants · NEET

Placentation is the way ovules are arranged inside the ovary. The five NEET types with fixed examples are: Marginal (pea), Axile (tomato, lemon, china rose), Parietal (Argemone, mustard), Basal (sunflower, marigold) and Free-central (Dianthus, Primrose). Memory hook: "My Aunt Prepares Basil Fresh" = Marginal, Axile, Parietal, Basal, Free-central.
Five Types of Placentation (ovary cross-sections)MarginalPeaAxile (septa)TomatoParietal (wall)MustardBasalSunflowerFree-centralDianthusAxile has septa; free-central has a central column but NO septa
Cross-sections of the ovary showing the five NEET placentation types with their standard examples. Axile has septa dividing chambers, while free-central has a central column but no septa.

Your doubts, answered

What is the difference between axile and free-central placentation?

Both have ovules attached to a central axis, so students mix them up. The key difference is the septa (walls). In AXILE placentation the ovary is divided into chambers by septa, and ovules are borne on the central axis where the septa meet (example: tomato, lemon, china rose). In FREE-CENTRAL placentation the septa are ABSENT, so the ovary is one chamber and ovules sit on a free central column (example: Dianthus, Primrose). Rule: axile = central axis WITH septa; free-central = central column WITHOUT septa.

Why is mustard parietal and not axile placentation?

Mustard (and Argemone) has a one-chambered ovary at first. A false septum (replum) later forms and makes it look two-chambered, but the ovules develop on the ovary WALL (the inner surface), not on a central axis. Ovules on the wall = parietal placentation. This false-septum trick is a common NEET trap, so remember mustard and Argemone as parietal examples.

Which placentation is found in pea?

Pea (Fabaceae) shows MARGINAL placentation. The ovary has a single chamber and the placenta forms a ridge along the ventral suture (one side). The ovules are borne on this ridge in two rows. Marginal placentation goes with a monocarpellary ovary. NEET often pairs 'pea = marginal placentation' in match-the-column questions.

What is basal placentation and its example?

In BASAL placentation the placenta develops at the BASE (bottom) of the ovary and usually a single ovule is attached to it. Examples: sunflower and marigold (family Asteraceae/Compositae). Remember: basal = base + usually one ovule. Do not confuse it with free-central, where many ovules sit on a central column.

Is tomato placentation axile or parietal?

Tomato is AXILE placentation. The ovary is multi-chambered (multilocular) with septa, and the ovules are attached to the central axis where the septa meet. Other axile examples are lemon (Citrus), china rose (Hibiscus) and onion (Liliaceae). If you see a chambered ovary with a central axis, it is axile.

⚠️ The NEET trap
✗ Mustard and Argemone are two-chambered, so they must be axile placentation.
✓ Mustard and Argemone are PARIETAL. The ovary starts one-chambered and becomes falsely two-chambered by a false septum (replum), but ovules stay on the ovary wall, not on a central axis. Wall = parietal.
🧠 A false septum does NOT make it axile. Ask: are ovules on the WALL or on the AXIS? Mustard = wall = parietal.

Real NEET questions

NEET 2024

Match List I with List II. List I: A. Rose, B. Pea, C. Cotton, D. Mango List II: I. Twisted aestivation, II. Perigynous flower, III. Drupe, IV. Marginal placentation Choose the correct answer from the options given below.

A · A-I, B-II, C-III, D-IV
B · A-IV, B-III, C-II, D-I
C · A-II, B-III, C-IV, D-I
D · A-II, B-IV, C-I, D-III ✓
Solution: Rose is a perigynous flower (II); Pea shows marginal placentation (IV); Cotton shows twisted aestivation (I); Mango is a drupe (III). So A-II, B-IV, C-I, D-III. This question directly tests that Pea = marginal placentation.
ReNEET 2026

Match List-I with List-II: List-I: A. Marginal placentation, B. Axile placentation, C. Parietal placentation, D. Free central placentation List-II: I. Argemone, II. Tomato, III. Primrose, IV. Pea Choose the correct answer from the options given below:

A · A-II, B-IV, C-I, D-III
B · A-IV, B-II, C-III, D-I
C · A-IV, B-III, C-I, D-II
D · A-IV, B-II, C-I, D-III ✓
Solution: Marginal - Pea (IV); Axile - Tomato (II); Parietal - Argemone (I); Free-central - Primrose (III). So A-IV, B-II, C-I, D-III. This is a pure placentation-example matching question, so keep the five standard examples memorised.

Solved Sexual Reproduction in Flowering Plants NEET PYQs

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Frequently asked

What are the five types of placentation in NEET?

Marginal, Axile, Parietal, Basal and Free-central. NCERT also names 'central', but the five above with fixed examples are what NEET tests.

What is placentation in simple words?

Placentation is the arrangement of ovules on the placenta inside the ovary of a flower. The placenta is the tissue to which ovules are attached.

Which placentation has ovules on the ovary wall?

Parietal placentation. Ovules are borne on the inner wall of the ovary, as in Argemone and mustard.

What is the difference between marginal and basal placentation?

Marginal has a single chamber with ovules on a ridge along one side (ventral suture) in two rows, like pea. Basal has the placenta at the base of the ovary with usually one ovule, like sunflower.

Which placentation shows septa in the ovary?

Axile placentation shows septa dividing the ovary into chambers, with ovules on the central axis. Free-central looks similar but has NO septa.

Related concepts:
Pistil: Stigma, Style, Ovary and Types of GynoeciumStructure of the Ovule: Funicle, Micropyle, NucellusMegasporogenesis and the Functional MegasporeFruit Development: True Fruits vs False FruitsAlternation of Generations in Angiosperms
Practise Biology for NEET:
Biology MCQs (free, chapter-wise)Sexual Reproduction in Flowering Plants PYQs