Intelligence, broadly defined

I am reading Mancuso and Viola's book defending the idea that plants are intelligent. (Brilliant Green, Island Press, 2013) Intelligence comes in degrees, even among humans. Plants are able to detect gravity, temperature, humidity, light, chemical gradients, etc. and respond by moving their roots, leaves, stems, flowers, and producing chemicals of various kinds for various purposes dependent upon their current situation and needs.  Like animals they try to survive and reproduce. They satisfy the definition of intelligence I defended in Skeptic, vol. 12, #3, pg 14, 2006. They have a cognitive architecture that is highly distributed. (I defined 5 different levels/kinds of intelligence in my 16 September 2010 blog.) I agree with Mancuso and Viola that if we were to contact space aliens we might need to have had experience with a wide variety of different intelligences.