Bamboo and grasses elongate by the activity of
a)	Secondary meristem	b)	Lateral meristem	c)	Apical meristem	d)	Intercalary meristem

(d)

Intercalary meristematic tissues are intercalated in between the permanent tissues. They may be present either at the base of internodes (e.g., grasses, wheat, etc) or at the base of leaf (e.g., Pinus) or at the base of node (e.g., mint). The activity of intercalary meristem also add to the length of plant or its organs.