The tissue responsible for the active vertical and horizontal growth in plants is called
Meristematic tissue
Meristematic tissues are composed of actively dividing cells and are found in the growing regions of the plant. According to their position in the plant, meristems are grouped as apical, lateral and intercalary.
Apical meristems: These are situated at the growing tip of stems and roots.
Lateral meristems: These are found beneath the bark and in vascular bundles of dicot roots and stems.
Intercalary meristems: They are located at the base of leaves or internodes.