Secondary tissues in a dicot stem are produced by

Options

A. phellogen
B. vascular cambium
C. apical meristems
D. axillary meristems

Explanation

Secondary vascular tissues , i.e., secondary xylem and pholem are formed by the vascular cambium . It is produced by two types of meristems , fascicular or intrafascicular and interfascicular cambium . Intrafascicular cambium is a primary meristem which occurs as strips in vascular bundles .
It divides to form secondary phloem on outer side and secondary xylem on the inner side .
Interfascicular cambium arises secondarily from the cells of medullary rays.
Phellogen or cork cambium is produced in the outer cortical cells of dicot stems . It is helpful in increasing the girth . Apical meristems are present at the tips of stem , root and their branches . They are responsible for increase in length of the plant . Axillary meristem is found in axillary buds . These cells are left behind from shoot apical meristem during the formation of leaves and elongation of stems .