(i) Due to more activity of certain portions of phellogen, the phellem cells are cut off very rapidly and hence, these cells are loosely arranged with a lot of intercellular spaces. These loosely arranged cells are called complementary cells and loosely arranged areas in the periderm are called lenticels.
(ii) The number of lenticels formed in a stem is variable.
(iii) Lenticels help in
(a) gas exchange. (b) lenticular transpiration and explain.