[marcosdumay]

Averaging the florests do not mean much.

As I've said, there are big areas of rain-florest in Brazil that rarely see less than 38°C during the day. There are also big areas of savanna that stay around that temperature for half a year (the half that rains). The fact that there are also cooler areas does nothing to explain how plants survive on those both.

I do think it's quite likely that plants keep leaves bellow the environment temperature, I'd just like somebody that knows it to confirm it or not.