Anatomy of Flowering Plants — BIOLOGY STD 11 Science — Question

Phelloderm, phellogen and phellem together constitute the periderm. Periderm is protective in function. Dicot stems produce cork cambium or phellogen in the outer cortical cells. Phellogen cells divide on both the outer side as well as the inner side to form secondary tissues. The secondary tissue produced on the inner side of the phellogen is called secondary cortex or phelloderm. On the outer side phellogen produces cork or phellem.