Cork is formed from (a) cork cambium (phellogen) (b) vascular cambium (c) phloem (d) xylem
Option A In hypodermis or outer cortical cells, a layer becomes meristematic which is known as cork cambium or phellogen. This phellogen also cuts off cells both on its outer side and inner side. The cells cut off on outer side are phellem or cork cells and cells cut off on inner side are phelloderm or secondary cortex. The phellem or cork cells are dead and have deposition of a fatty substance called suberin (i.e., cork cells are suberized). Suberin is impervious to water and thus cork cells are buoyant (i.e., float on water). Phellem, phellogen and phelloderm collectively constitute periderm.