In a nutshell, language is not very well color managed. If we painted well lighted foliage with true primary green, it would look way to cool to most people, or like it was in deep shadows. Another interesting case is the way the Japanese relate blue and green in language use. But there's a lot of yellow out there in the world, and that's the color that goes fastest on my Canon printer. Watch the RGB values as you run the Arrow across those "green" leaves.