Plant tissues are divided into two broad categories:

(i) Meristematic tissue: It is further subdivided into apical, lateral, and intercalary meristems.

(ii) Permanent tissue: They are of two types.

(a) Simple permanent tissues include parenchyma, collenchyma, and sclerenchyma.

(b) Complex tissues include xylem and phloem.

Simple Tissue: These tissues are composed structurally and functionally of similar cells.

They are of three types.

(i) Parenchyma: It is widely distributed in plant bodies such as stems, roots, leaves, flowers, and fruits. Its cells are isodiametric and contains live protoplasm. It serves as a food storage and packing tissue. It also stores waste products of plants.

(ii) Collenchyma: The cells of collenchyma are located below the epidermis of dicotyledon stem and petiole. It consists of living cells and is characterised by the deposition of extra cellulose at the corners of the cell. It is a mechanical tissue in young plants. It also provide elasticity to the plant, particularly stem of dicots.

(iii) Sclerenchyma: It consists of dead lignified cell. The sclerenchyma is mainly mechanical and protective in function. It occurs in abundance or in patches in definite layers in stems, roots, veins of leaves, hard covering of seeds, and nuts. It provides mechanical support to the plant.