Lateral Meristem: Vascular Cambium and Cork Cambium
Biology · Anatomy of Flowering Plants · NEET
A lateral meristem is a dividing tissue that sits along the SIDES of a root or stem. There are two: the vascular cambium (makes new xylem and phloem) and the cork cambium or phellogen (makes cork/bark). They add GIRTH (thickness), so this is called secondary growth. Memory hook: "Lateral = wideR" — lateral meristems make a dicot stem WIDER, not taller.
In a dicot stem, the vascular cambium ring makes secondary xylem inward and secondary phloem outward, while the cork cambium near the surface makes protective cork. Both are lateral meristems that increase girth.
Your doubts, answered
Is vascular cambium a lateral meristem?
Yes. Vascular cambium lies along the sides of the stem/root between xylem and phloem, so it is a lateral meristem. It has two parts: fascicular (intrafascicular) cambium inside the vascular bundle, and interfascicular cambium formed between bundles. Both add girth, not height.
What is the difference between vascular cambium and cork cambium?
Vascular cambium is deeper inside and makes secondary xylem (inside) and secondary phloem (outside). Cork cambium (phellogen) is nearer the surface and makes cork/phellem (outside, dead) and secondary cortex/phelloderm (inside, living). Vascular cambium adds conducting tissue; cork cambium adds a protective bark.
Which meristem is responsible for secondary growth?
Lateral meristems. Both the vascular cambium and the cork cambium are lateral meristems, and their divisions increase the girth of the plant. This thickening is called secondary growth and happens in dicot stems and roots, not in monocots.
Is cork cambium the same as phellogen?
Yes, they are two names for the same tissue. Phellogen = cork cambium. It cuts off cork (phellem, dead, suberised) on the outer side and secondary cortex (phelloderm, living) on the inner side.
Does lateral meristem increase length or girth?
Girth only. Lateral meristems make the plant thicker (wider). Length increase comes from apical meristems (tips) and intercalary meristems (base of internodes), not from lateral meristems.
Is intercalary meristem a lateral meristem?
No. Intercalary meristem is a primary meristem left behind at the base of internodes/leaves and it adds LENGTH. Only vascular cambium and cork cambium are lateral meristems. This exact mix-up was tested in NEET 2023.
⚠️ The NEET trap ✗ Picking axillary buds or intercalary meristem as a lateral meristem when asked to list them. ✓ Only fascicular vascular cambium, interfascicular cambium and cork cambium are lateral meristems (NEET 2023 answer: B, C, D only). 🧠 Lateral = along the SIDES + adds GIRTH. Axillary buds come from the apical region; intercalary meristem adds length. Neither is lateral.
Real NEET questions
NEET 2023
Consider the following plant tissues. Identify the lateral meristems among the above. (A) Axillary buds (B) Fascicular vascular cambium (C) Interfascicular cambium (D) Cork cambium (E) Intercalary meristem
A · (A), (B), (C) and (E) only
B · (A), (B), (D) and (E) only
C · (A), (C) and (D) only
D · (B), (C) and (D) only ✓
Solution: Lateral meristems lie along the sides of roots and stems and cause secondary growth (increase in girth). These are the fascicular (intrafascicular) vascular cambium, the interfascicular cambium and the cork cambium (phellogen) — so (B), (C) and (D). Axillary buds arise from the shoot apical region, and intercalary meristem is a primary meristem at the base of internodes/leaves that adds length. Hence the answer is (D).
NEET 2019
In the dicot root the vascular cambium originates from:
A · Tissue located below the phloem bundles and a portion of pericycle tissue above protoxylem. ✓
B · Cortical region.
C · Parenchyma between endodermis and pericycle.
D · Intrafascicular and interfascicular tissue in a ring.
Solution: In a dicot root the vascular cambium is completely secondary in origin. It first appears as strips of conjunctive parenchyma just below (internal to) the phloem, then pericycle cells above the protoxylem also become meristematic and join them to complete a wavy cambial ring. So the answer is (A). Option (D) describes the dicot STEM cambium, not the root.
Solved Anatomy of Flowering Plants NEET PYQs
Try the real previous-year questions from this chapter — each with the answer and a full solution.
The vascular cambium and the cork cambium (phellogen). Both lie along the sides of the axis and add girth.
What does vascular cambium produce?
Secondary xylem toward the inside and secondary phloem toward the outside. Usually more xylem is made than phloem, so the wood layer is thicker.
What does cork cambium produce?
Cork (phellem, dead and suberised) toward the outside and secondary cortex (phelloderm, living) toward the inside. Together with the cork cambium these form the periderm.
Why is secondary growth absent in monocots?
Monocot vascular bundles are closed — they have no cambium between xylem and phloem. Without a vascular cambium there is no lateral meristem to add girth, so most monocots do not show typical secondary growth. This is a common NEET point.
What is the difference between fascicular and interfascicular cambium?
Fascicular (intrafascicular) cambium is the strip of cambium already present inside a vascular bundle. Interfascicular cambium forms fresh from medullary ray cells between the bundles. Together they make a complete cambial ring in the dicot stem.
