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Normally secondary growth is absent in monocots. Monocots live for a short period of time and complete its life cycle. Example:jawar, maize, rice etc., But Dracena shows abnormal secondary growth being a monocot stem. Dracena belongs to Lilliaceae family. Formation of Periderm: During secondary growth few peripheral cells of general cortex becomes active and forms Meristem. This acts as Cork cambium or Phellogen. This cork cambium cuts off Cork tissue or Phellem towards outside and secondary cortex or phelloderm towards inside. By this periderm is formed. Formation of cambium: The inner peripheral cells of general cortex becomes meristemetic and forms cambium. Cambium forms parenchyma cells and xylem elements in its inner side. After a short period of time activity changes. Phloem is formed in such a way that phloem is surrounded by xylem. This type of vascular bundles are called Amphiphloic type. In which phloem is surrounded by xylem. ...

SECONDARY GROWTH IN PLANTS: Increase in width of the plant is considered as secondary growth. Secondary growth is seen in second year of plant growth.  Secondary growth takes place in two steps. They are: 1.Cortical or Extra-stelar growth. 2. Stelar growth CORTICAL OR EXTRA-STELAR GROWTH: Formation of periderm: The cortex of the stem gets modified to meristem and acts as Cork cambium or Phellogen then it continuously divides towards outer side to form Cork tissue or Phellem and divides inner side to form Secondary cortex or Phelloderm The Phellogen, Phellem and Phelloderm together called as Periderm. Thus plants increase in its width. STELAR GROWTH: Formation of Intrafascicular cambium: The cambium which is present between xylem and phloem gets activated(able to divide) and forms Intrafascicular cambium. Formation of Interfascicular cambium: Medullary rays which is present between vascular bundles develops a cambium, that cambium is call...