Placentation Types: Marginal, Axile, Parietal, Basal, Free Central
Biology · Morphology of Flowering Plants · NEET
Placentation is the arrangement of ovules inside the ovary. The five NCERT types are: marginal (pea), axile (china rose, tomato, lemon), parietal (mustard, Argemone), basal (sunflower, marigold) and free-central (Dianthus, Primrose). Memory hook: "My Aunt Puts Basil Freely" = Marginal, Axile, Parietal, Basal, Free-central.
Ovary cross-sections: marginal (ridge on one side, pea), axile (ovules on central axis with septa, china rose), parietal (ovules on inner wall, mustard), basal (single ovule at base, sunflower) and free-central (central axis, no septa, Dianthus).
Your doubts, answered
What is placentation in simple words?
Placentation is just where and how the ovules sit inside the ovary. The placenta is the cushion-like tissue that holds the ovules. NEET asks you to match each pattern to its plant example, so learn the type WITH its example, not alone.
What is the difference between axile and free-central placentation?
Both have ovules on a central axis, so students mix them up. In AXILE the ovary is multilocular (many chambers) and septa (walls) ARE present, so ovules sit on the central axis where the walls meet (china rose, tomato, lemon). In FREE-CENTRAL the septa are ABSENT, so the central axis stands free in one chamber and carries the ovules (Dianthus, Primrose). One word decides it: septa present = axile, septa absent = free-central.
Which placentation is found in pea?
Pea shows MARGINAL placentation. The ovary has one carpel, and the placenta forms a ridge along the ventral suture. The ovules are borne in two rows on this ridge. This is a very common NEET match (Pea to Marginal).
What is the difference between parietal and axile placentation?
In PARIETAL the ovary is one-chambered and ovules develop on the inner wall or peripheral part (mustard, Argemone); it may look two-chambered only because of a FALSE septum. In AXILE the ovary is truly multilocular with real septa and ovules on the central axis (china rose, tomato, lemon). Inner wall = parietal, central axis = axile.
Which placentation has a single ovule?
BASAL placentation. The placenta develops at the BASE of the ovary and a single ovule is attached to it. Examples are sunflower and marigold (family Asteraceae). If a question says one ovule at the base, it is basal.
Free-central placentation is found in which plant?
Dianthus and Primrose (NCERT examples). NEET 2016 Phase 2 asked exactly this, with the answer Dianthus. Remember: ovules on a free central axis with NO septa.
⚠️ The NEET trap ✗ China rose has parietal placentation because its ovules look like they are on the wall. ✓ China rose has AXILE placentation. Its ovary is multilocular with real septa and the ovules sit on the central axis where the walls meet. Parietal examples are mustard and Argemone (one-chambered ovary, ovules on the inner wall). 🧠 Trap word is the EXAMPLE, not the type. Lock the pairs: china rose/tomato/lemon = axile; mustard/Argemone = parietal. NEET keeps swapping these two.
Real NEET questions
2019
Placentation in which ovules develop on the inner wall of the ovary or in peripheral part, is
A · Basal
B · Axile
C · Parietal ✓
D · Free central
Solution: In parietal placentation the ovules develop on the inner wall of the ovary or its peripheral part. The ovary is one-chambered but may look two-chambered due to a false septum, as in mustard and Argemone. NCERT Ch 5, p.65.
2023
Axile placentation is observed in
A · Mustard, Cucumber and Primrose
B · China rose, Beans and Lupin
C · Tomato, Dianthus and Pea
D · China rose, Petunia and Lemon ✓
Solution: Axile placentation has the placenta axial with ovules on it in a multilocular ovary: china rose, tomato and lemon; Petunia (Solanaceae) is also axile. Distractors mix parietal (mustard), marginal (beans, pea) and free-central (Dianthus, Primrose). NCERT Ch 5, p.65.
2016
Free-central placentation is found in
A · Dianthus ✓
B · Argemone
C · Brassica
D · Citrus
Solution: In free-central placentation ovules are on a central axis and septa are absent, as in Dianthus and Primrose. Argemone is parietal, Brassica (mustard) is parietal, Citrus is axile. Answer: Dianthus. NCERT Ch 5, p.65.
Solved Morphology of Flowering Plants NEET PYQs
Try the real previous-year questions from this chapter — each with the answer and a full solution.
How many types of placentation are there in NCERT?
NCERT lists five main types for NEET: marginal, axile, parietal, basal and free-central. (The text also mentions 'central' but the exam-important set is these five.)
What is the easiest way to remember placentation examples?
Learn fixed pairs: Marginal-Pea, Axile-China rose/Tomato/Lemon, Parietal-Mustard/Argemone, Basal-Sunflower/Marigold, Free-central-Dianthus/Primrose. NEET matching questions use exactly these pairs.
Is placentation part of the ovary or the ovule?
Placentation describes the arrangement of ovules INSIDE the ovary. The placenta is a cushion of ovary tissue that holds the ovules; it belongs to the gynoecium.
Why is placentation important for NEET?
NEET asks direct one-liners and List-I to List-II matching almost every year (2016, 2019, 2023, 2024). Correct type-to-example pairing gives easy marks, so it is high-yield for the exam.
Which family shows basal placentation?
Asteraceae (Compositae) shows basal placentation, seen in sunflower and marigold, with a single ovule at the base of the ovary.
