Define the following terms:
$(i)$ Dorsiventral leaf
$(ii)$ Periderm

(N/A) $(i)$ In a dicot leaf,the mesophyll tissue is differentiated into palisade parenchyma and spongy parenchyma,which are located towards the upper and lower epidermis,respectively. Due to this differentiation,it is called a dorsiventral leaf.
$(ii)$ The phellogen (cork cambium),phellem (cork),and phelloderm (secondary cortex) are collectively known as the periderm.