Very tall grass is found on plains and tundra in the map.
It shouldn't be on Tundra. Refer to my excel guide so you can see where features can be placed.
Oasis can't be next to each other, next to river and next to coast. Can't be placed on Hill.
Flood Plains must be on tile bordering river and must be on flat terrain.
Cactus, Tar Pit and Peat Bog must be on flat terrain.
Forest/Ancient Forest are essentially same thing.
Allowed features on terrain (Earth):
Salt Flat - Nothing.
Dunes - Oasis, Flood Plains, River, Desert Outcrop.
Desert - Oasis, Flood Plains, Cactus, Savanna, Tar Pit, Desert Rocks, River.
Scrub - Oasis, Flood Plains, Forest, Cactus, Savanna, Very Tall Grass, Tar Pit, Rainwater Basin, Desert Rocks, River.
Plains - Flood Plains, Forest, Bamboo, Savanna, Very Tall Grass, Tar Pit, Peat Bog, Rainwater Basin, River.
Grassland - Jungle, Forest, Swamp, Bamboo, Savanna, Very Tall Grass, Tar Pit, Peat Bog, Rainwater Basin, River.
Taiga - Forest, Tar Pit, Peat Bog, Rainwater Basin, Polar Rocks, River
Tundra - Tar Pit, Rainwater Basin, Polar Rocks, River.
Permafrost - Polar Rocks, River.
Ice - Tar Pit, Polar Rocks.
Jagged - Tar Pit, Volcano, Polar Rocks, River.
Badland - Tar Pit, Volcano, Desert Rocks, River.
Barren - Tar Pit, Volcano, Dark Rocks, River.
Rocky - Forest, Bamboo, Savanna, Very Tall Grass, Tar Pit, Volcano, Dark rocks, River.
Lush - Jungle, Forest, Swamp, Bamboo, Mangrove, Very Tall Grass, Tar Pit, Rainwater Basin, River
Marsh - Jungle, Forest, Swamp, Bamboo, Mangrove, Very Tall Grass, Tar Pit, Rainwater Basin, River
Muddy - Jungle, Flood Plains. Forest, Swamp, Bamboo, Mangrove, Very Tall Grass, Tar Pit, Rainwater Basin, River.
Water features:
Reef and Coral - Temperate Coasts and Lakes.
Sea Grass - Temperate/Tropical Coasts
Kelp - Temperate/Polar Coasts
Ice - Polar Coasts/Seas/Oceans/Trenches.