Palm is a monocotyledonous plant,yet it increases in girth. Why and how?

(N/A) Although palm is a monocotyledonous plant,it exhibits an increase in girth. This occurs because of the division and expansion of parenchymatous cells within the ground tissue. This repeated division and subsequent enlargement of cells increase the girth of the stem. This specific type of growth is known as $diffused$ $secondary$ $growth$.