Arrange in increasing power of osmotic pressure $$\rightarrow$$ Xerophytes, mesophytes, hydrophytes & halophytes.
Osmotic pressure is the minimum pressure which needs to be applied to a solution to prevent the inward flow of its pure solvent across a semipermeable membrane. It is also defined as the measure of the tendency of a solution to take in pure solvent (which belongs to the solution under discussion) by osmosis. So you should know that the plant which is in the high need for water has the lowest osmotic pressure. So the arrangement of the plants according to their increasing osmotic pressure will be;