Question

Extrastelar secondary growth takes place by

• A. Vascular cambium
• B. Phellogen
• C. Phellem
• D. Phelloderm

Answer 1

Answer: (B)

Phellogen

Intrafascicular cambium (present between xylem and phloem) and interfascicular cambium together form a complete cambium ring called as vascular cambium or just cambium. Vascular cambium exhibits two patterns of division; multiplicative divisions or additive divisions. During secondary growth, rupturing of the epidermal cell and outer cortex by secondary tissues induces the formation of the new protective layer, periderm. Pericycle resumes the meristematic activity and divides to form cork cambium /phellogen. The cork cambium exhibit meristematic activity and produces cork /phellem towards the periphery and phelloderm on inside i.e., extra stellar growth

So, the correct answer is 'Phellogen'