Differences between parenchyma, collenchyma and sclerenchyma

Parenchyma

These are living cells with thin walls.

Cells are uniformly thin.

The cells are loosely packed with large intercellular spaces.

Collenchyma

These are living cells with slightly thick walls.

Cells are elongated.

The cells are irregularly thickened at the corners with very little intercellular spaces.

Sclerenchyma

These are dead cells with thick cell walls.

Cells are long and narrow.

The cells are thickened due to lignin. These are so thick that there is no internal space inside the cell.