Figure 2.13 Salt balance in mangrove trees. (a) The roots of mangrove trees are frequently submerged in saltwater at high tide. These trees are from Palau, an island in the South Pacific. (b) Specialized salt glands in the leaves of the button mangrove (Conocarpus recta) excrete a salty solution. As the solution evaporates, it leaves behind salt crystals on the outer surface of the leaves.

Photos by (a) Reinhard Dirscherl/Alamy, and (b) Ulf Mehlig.