Simple permanent tissue with thin-walled living cells is parenchyma. Parenchyma cells with abundant air cavities in between are called aerenchyma. Air cavities filled up with gases help the aquatic plants in floating. Water hyacinth is an example that has spongy petioles which enclose a lot of air in its aerenchyma. Air makes the plant lighter than water so that it is able to float on the surface of the water.

Simple permanent tissue with thin-walled living cells is parenchyma. Parenchyma consists of relatively unspecified, large and thin-walled cells that are made up of cellulose. The parenchyma cells are rounded or isodiametric. It encloses a dense cytoplasm that contains a small nucleus and surrounds a large central vacuole. Intercellular spaces are abundant.

Simple permanent tissue walls of whose cells are unevenly thickened by additional cellulose deposition are called collenchyma. Collenchyma cells have no intercellular spaces between them. They have a distinct nucleus and dense cytoplasm.

Xylem and Phloem are the two types of complex tissues, also called conducting tissues or vascular tissues, and together they form vascular bundles. The complex permanent tissue associated with the conduction of water and mineral salts in vascular plants is called the xylem. Xylem is a complex tissue as it consists of different types of cells, both living and non-living, namely-Tracheid, Trachea or Xylem vessels, Xylem parenchyma or Wood parenchyma and Xylem fibre or Wood fibre.