Meristematic tissue responsible for increase in girth of tree trunk is (a) intercalary meristem (b) lateral meristem (c) phellogen (d) apical meristem.
Option B Lateral meristems are the meristems which are present along the lateral sides of stem and roots. They divide only in radial direction. Intrastelar or vascular cambium ring formed by intrafascicular (also called fascicular) and interfascicular cambium; and cork cambium (phellogen) are examples of this type of meristem. These meristems are responsible for increase in girth of stem and roots.
