I see where you’re going with the original color scheme, but maybe the green is too saturated for something based in nature, like a mushroom. I like the green of 5 better. Feels a little more natural, like a mushroom. I like the overall design of 5 better. Green evokes certain emotions and associations, like poison, nature, maybe some mystical presence. Then the brown is kind of neutral, but also natural, like mud or dirt. Then the little pops of a more saturated green kind of give a warning, like a brightly colored poisonous animal. Out of all of these, 5 attracts my eye the most.
Have you heard of a color gamut? It might be useful to use in this instance since you’re going for a specific look. Take a look at this video for more info: https://www.youtube.com/watch?v=qfE4E5goEIc
And remember, colors are relative to each other, and changing just one can have a huge impact in the overall design. Check out the Bezold effect, like this: http://www.opticalspy.com/uploads/1/4/4/9/144966/4249055_orig.gif
