Cacti have a thick, waxy layer on the epidermis - this reduces water loss by evaporation because the layer is waterproof
Cacti also close their stomata at the hottest times of the day when transpiration rates are the highest.
They have spines instead of leaves - this reduces the surface area for water loss.
Marram grass adaptations
Has stomata that are sunk in pits, so they're sheltered from the wind. This traps moist air in the pits and helps to slow transpiration down by lowering the water potential gradient.
Has a layer of 'hairs' on the epidermis - this also traps moist air round the stomata, which reduces the water potential gradient between the leaf and the air, slowing transpiration down.
In hot or windy conditions they roll their leaves - again this traps moist air, slowing down transpiration. It also reduces the exposed surface area for losing water and protects the stomata from wind.
Has a thick, waxy layer on the epidermis to reduce water loss by evaporation.
