Alva Noe writes today about plant behaviour and that plants exhibit a form of intelligence.  He ponders if they can have minds without brains.  

I recommend he read Alfred North Whitehead's Modes of Thought and then some other work on minds and bodies in process thought.  Maybe I should send him a copy of my dissertation?  

For process philosophers, plants do not have minds, but all actual occassions (the fundamental unites of actuality, the ontos on) experience subjectively and the more complex the system the more complex the subjective experience.  This metaphysical view explains the behaviour of plants.