They are actually from a mostly round grunge brush. I used 2 shades of green with the "Use Color from Gradient" then I just wriggle them a bit to fill them in so they aren't full of holes. I touch them up flipping between my two colors so the overall image has the right look. (so one side isn't all yellowish and the other green). Use the curves to get the color a little better. I then Duplicate the layer and use a 'find/edge', colorize the result, merge it down (this creates the leaf like texture. I use my eraser to break things up and add some trails where I want (I used a brush called 'inner space' I think which has a lot of holes in it). The green grass/moss flooring was a by product which I liked.

I will attempt this again and track my steps better. I had created one set I didn't like and blew away a bunch of layers before I created this so sorry if I'm a bit vague on what exactly I used. I promise to do better next time