Describe Meristems term in diversity of life?

Plant development goes through a stage known as primary growth, which produces what is referred to as the "primary plant body." A primary plant body is the type of body that herbaceous plants have--one whose green, above ground parts die after the growing season. Young woody plants that arise during germination of the seed and before they develop woody tissues and mature are also considered to be primary plant bodies.

The typical primary plant body consists of 3 basic kinds of tissue: the vascular tissue, whose function is to transport substances throughout the plant, the epidermal tissue, whose function is to protect the interior tissues, and the so-called ground tissue, with 3 different functions: photosynthesis, storage and support. All of these tissues are constantly being added to the plant by special dividing cells, which accounts for the plant's increase in height, root penetration into the ground, as well as expansion in girth. The plant's fast growth rate does not really allow for a lot of time to build specialized structures, so these cells are functional at an early stage in their lives.

Plants grow--that is--they add new cells from special meristematic tissues that divide and produce new cells. There are 3 different types of fundamental meristematic tissues found in vascular plants: the procambium, the protoderm, and the ground meristem. Procambium produces the cells that eventually develop and mature into vascular tissue is called xylem and phloem; the protoderm tissue gives rise to the epidermis; and the ground tissue is known as parenchyma, collenchyma, and sclerenchyma.