Do drought-hardened

plants suffer from fever? In a recent article by David Beerling and colleagues1, an increase in stomatal density accompanying the development of large planate leaves is discussed as an adaptation to the increasing interception of solar radiation. A concomitant increase in transpiration was predicted to represent an essential requirement for maintaining cool and viable leaf temperatures. Stomata represent diffusion resistances for CO2 and water vapour. However, plants are capable o