They are printed from light to dark. Here's the base light yellow green then the second dark green.
Then the third run is printed in red.
Here's the final four color print with the black detail plate added of a laurel sumac seedling. I ripped the specimen out by the roots where it popped up in my front yard.
Here's a final four pass print of leaves and baby acorn buds from a Valley oak, my personal favorite tree of all time.