What are: (i)Periclinic divisions (ii) Anticlinic divisions ?

In a cylindrical structure like a root or a stem ; when cell division occurs at the right angle to the length of an existing cell / s ; then it is ' Anticlinal division. It adds to the number of existing cells but their rows around that organ ( Root / Stem ) remain the same in number .As above ...... ; when cell division occurs parallel to the length of the existing cell / s then it is 'Periclinal Division '.It results in the increase of the cell numbers as well as the cell rows around that organ ( Root Stem )..In the diagram below = Multiplicative division means anticlinal division And Additive division means Periclinal division .