Thanks everyone for your kind comments. I have been struggling with how to depict deserets and swamps and think I might keep the subtle discolouration I have used here for areas of aridity. The swamps however are completely different. I created an area mixing one of Ramah's tree brushes in with his dead looking tree brush to try and hint at a swamp but I can't say as I am really satisfied with the result. Perhaps I should create more of these areas to fill in some of the blank spots. And I think I will add some more lakes and rivers and crop out some of the ocean.

Thanks again everyone!