Phellogen (Cork Cambium)

Phellogen, more commonly called the cork cambium, is the secondary lateral meristem responsible for producing the entire periderm. Unlike the vascular cambium, which is built of two distinct cell types (fusiform and ray initials), the cork cambium is comprised of a single, homogeneous population of meristematic cells. It can arise from several different starting tissues depending on the species and organ - the epidermis, the cortex, the phloem, or the pericycle (an extrastelar origin, i.e., arising outside the stele) - and once established, its cells divide periclinally, producing neat, radially arranged files of daughter cells on both faces. The daughter cells cut off toward the outer side differentiate into phellem (cork); the daughter cells cut off toward the inner side differentiate …