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Greenery and Forests would mostly come in the northern section of the map, where real live Washington/North Part of California is IRL.
Even tho it's a desert region, there should be at least one good forest in the game still, and a forest mountain as well, since it's an overall rocky region.
Good candidates for that are: Sunkern, Seedot, Turtwig, Petilil, Skiddo, Morelul
Since there are plenty of desert/Oasis Areas around the region, Plant Pokemon that can survive in that Environment would also be found in those places, Pokemon like: Cacnea, Carvine, Maractus, Exeggcute(Around Cities), Roselia(In cities, with budew in forests), and Tropius. Dhelmise is a nice little Pokemon you can maybe find on a sea route/Swimming in port Cities