The girth of stem increases due to (a) apical meristem (b) lateral meristem (c) intercalary meristem (d) vertical meristem
(b) lateral meristem The girth of the stem is increased due to Lateral meristem. Apical meristems are found on the apices / growing parts of a plant such as tips of shoots, roots, etc. Intercalary meristems are located in internodes, the base of the grass and between leaves. They are found beneath the bark (called cork cambium) and in vascular bundles of dicot roots and stems (called vascular cambium) as thin layers. This increase in the diameter and girth of the plant is called secondary growth. The apical meristem is situated at the growing tip of stems, roots and also at the apices of the leaf. They bring about elongation, i.e., an increase in the height (primary growth) of the plant. Intercalary meristem is located at the base of the leaf and internode and produces an increase in the length of an organ.
