"Both growth and differentiation in higher plants are ‘open’" Comment.

In higher plants, when growth occurs new cells are always being added to the plant body by the activity of the meristem. Such a type of growth is referred to as open form of growth. Even differentiation in plants is open because cells or tissues arising out of the same meristem have different structures at maturity. The final structure at maturity of a cell / tissue is determined by the location of the cell within.